Breeding semi-dwarf varieties to improve lodging resistance has been proven to be enormously successful in increasing grain yield since the advent of the ＂green revolution.＂ However, the breeding of the majority of ...Breeding semi-dwarf varieties to improve lodging resistance has been proven to be enormously successful in increasing grain yield since the advent of the ＂green revolution.＂ However, the breeding of the majority of semi-dwarf rice varieties in Asia has been dependent mainly on genetic introduction of the mutant alleles of SD1, which encodes a gibberellin （GA） 20-oxidase, OsGA20ox2, for catalyzing GA biosynthesis. Here, we report a new rice lodging-resistance gene, Shortened Basal lnternodes （SBI）, which encodes a gibberellin 2- oxidase and specifically controls the elongation of culm basal internodes through deactivating GA activity. SBI is predominantly expressed in culm basal internodes. Genetic analyses indicate that SBI is a semidominant gene affecting rice height and lodging resistance. SBI allelic variants display different activities and are associated with the height of rice varieties. Breeding with higher activity of the SBI allele generates new rice varieties with improved lodging resistance and increased yield. The discovery of the SB! provides a desirable gene resource for producing semi-dwarf rice phenotypes and offers an effective strategy for breeding rice varieties with enhanced lodging resistance and high yield.展开更多
The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic...The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic variation associated with vegetation restoration and further to explore the role of soil microbiology in vegetation restoration mechanism of degraded karst regions,we measured microbial biomass C and basal respiration in soils during vegetation restoration in Zhenfeng County of southwestern Guizhou Province,China.The community level physiological profiles(CLPP) of the soil microbial community to were estimated determine if vegetation changes were accompanied by changes in functioning of soil microbial communities.The results showed that soil microbial biomass C and microbial quotient(microbial biomass C/organic C) tended to increase with vegetation restoration,being in the order arboreal community stage > shrubby community stage > herbaceous community stage > bare land stage.Similar trend was found in the change of basal respiration(BR).The metabolic quotient(the ratio of basal respiration to microbial biomass,qCO 2) decreased with vegetation restoration,and remained at a constantly low level in the arboreal community stage.Analyses of the CLPP data indicated that vegetation restoration tended to result in higher average well color development,substrate richness,and functional diversity.Average utilization of specific substrate guilds was highest in the arboreal community stage.Principle component analysis of the CLPP data further indicated that the arboreal community stage was distinctly different from the other three stages.In conclusion,vegetation restoration improved soil microbial biomass C,respiration,and utilization of carbon sources,and decreased qCO 2,thus creating better soil conditions,which in turn could promote the restoration of vegetation on degraded karst regions.展开更多
The effect of paleo-Pacific subduction on the geological evolution of the western Pacific and continental China is likely complex. Nevertheless, our analysis of the distribution of Mesozoic granitoids in the eastern c...The effect of paleo-Pacific subduction on the geological evolution of the western Pacific and continental China is likely complex. Nevertheless, our analysis of the distribution of Mesozoic granitoids in the eastern continental China in space and time has led us to an interesting conclusion： The basement of the continental shelf beneath East and South China Seas may actually be of exotic origin geologically unrelated to the continental lithosphere of eastern China. By accepting the notion that the Jurassic- Cretaceous granitoids in the region are genetically associated with western Pacific subduction and the concept that subduction may cease to continue only if the trench is being jammed, then the termination of the granitoid magmatism throughout the vast region at -88±2 Ma manifests the likelihood of ＂sudden＂, or shortly beforehand （- 100 Ma）, trench jam of the Mesozoic western Pacific subduction. Trench jam happens if the incoming ＂plate＂ or portion of the plate contains a sizeable mass that is too buoyant to subduct. The best candidate for such a buoyant and unsubductable mass is either an oceanic plateau or a micro-continent. We hypothesize that the basement of the Chinese continental shelf represents such an exotic, buoyant and unsubductable mass, rather than seaward extension of the continental lithosphere of eastern China. The locus of the jammed trench （i.e., the suture） is predictably located on the shelf in the vicinity of, and parallel to, the arc-curved coastal line of the southeast continental China. It is not straightforward to locate the locus in the northern section of the East China Sea shelf because of the more recent （〈20 Ma） tectonic re-organization associated with the opening of the Sea of Japan. We predict that the trench jam at - 100 Ma led to the re-orientation of the Pacific plate motion in the course of NNW direction as inferred from the age-progressive Emperor Seamount Chain of Hawaiian hotspot origin （its oldest unsubdued Meiji and Detroit seamounts are -82 M展开更多
This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005...This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance （CRF1） and polymer materials （CRF3） increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer （RSF1）. Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.展开更多
Objective： To investigate brain activity patterns during acupuncture in stroke patients, and to compare the result with normal subjects using functional magnetic resonance imaging （fMRI）. Methods： A total of 11 st...Objective： To investigate brain activity patterns during acupuncture in stroke patients, and to compare the result with normal subjects using functional magnetic resonance imaging （fMRI）. Methods： A total of 11 stroke patients with motor weakness and 10 healthy subjects were studied, fMRI was performed during acupuncture on the left side at points Quchi （Llll） and Zusanli （ST36）. Data were analyzed using statistical parametric maps of brain activation induced by acupuncture stimulation. Results： The results showed that stimulation of both LI11 and ST36 produced significantly different brain activation patterns between the two groups. The normal group showed a greater overall activation than the stroke group. In the normal group, parts of the frontal lobe, parietal lobe, sub-lobar, cerebellum and midbrain regions were activated by acupuncture at the left LI11. On the other hand, only the right side of the inferior parietal Iobule region was activated in the stroke patients. When the left ST36 was stimulated in the normal group, both sides of the frontal lobe, parietal lobe, temporal lobe, and sub-lobar, and the left side of occipital lobe, and the right side of cerebellum and midbrain regions were activated. For the same stimulation in the stroke group, only both sides of the inferior parietal Iobule and cerebellum regions were activated （P〈0.05, cluster level）. Deactivation pattern was not noted during any acupuncture stimulation in both groups. Conclusion： Brain signal activations during the same acupuncture were different between the healthy and the stroke patients, and the effects showed a correlation of different acupuncture points.展开更多
Background There is still a paucity of data on hepatitis B virus （HBV） subgenotype prevalence in North China based on sequencing of large-size samples. In addition, whether HBV genotypes impact drug-resistance-assoc...Background There is still a paucity of data on hepatitis B virus （HBV） subgenotype prevalence in North China based on sequencing of large-size samples. In addition, whether HBV genotypes impact drug-resistance-associated and HBV e antigen （HBeAg）-Ioss-associated mutations in patients with chronic hepatitis B （CHB） is still under investigation. This study aimed to disclose clinical prevalence of HBV genotypes/subgenotypes in North China and the clinical implications of HBV genotype classification in respect to HBeAg loss and drug-resistant occurrence. Methods Sera were collected from 1301 nucleos（t）ide analog-experienced CHB patients. Viral DNA was extracted and used as template for HBV genome amplification by nested PCR. DNA sequencing was performed for the analysis of HBV genotypes/subgenotypes, drug-resistance-associated mutations in polymerase gene and HBeAg-loss-associated mutations in precore/basal core promoter （BCP） regions. Results HBV/B, HBV/C, and HBV/D were detected in 190 （14.6%）, 1096 （84.2%）, and 15 （1.2%） patients, respectively. HBV/B2 （182/190）, HBV/C2 （1069/1096）, and HBV/D1 （12/15） were predominant subgenotypes within individual genotypes. By contrast, C2 prevalence is relatively lower in Beijing area （77.2%） than in other north areas （84.9%-87.4%）. HBV/C-infected patients had an older age and a lower serum albumin level but similar HBV DNA and alanine aminotransferase （ALT） levels compared to HBV/B-infected patients. HBV/C infection had a higher incidence of lamivudine-resistant mutations rtM2041N （44.9% vs. 30.2%, P 〈0.01） and BCP mutations A1762T＋G1764A （65.8% vs. 40.0%, P〈0.01） compared with HBV/B infection. Conclusions C2 is the most prevalent HBV subgenotype followed by B2 in CHB patients in North China; and HBV genotype prevalence is influenced by immigrant population. HBV/C infection is likely to have longer disease duration and severer liver functional impairment and might be more susceptible to develop lamivudine res展开更多
The Hepatitis B Virus(HBV) has a worldwide distribu-tion and is endemic in many populations. It is constantly evolving and 10 genotypic strains have been identified with varying prevalences in different geographic reg...The Hepatitis B Virus(HBV) has a worldwide distribu-tion and is endemic in many populations. It is constantly evolving and 10 genotypic strains have been identified with varying prevalences in different geographic regions. Numerous stable mutations in the core gene and in the su-rface gene of the HBV have also been identified in untreated HBV populations. The genotypes and viral variants have been associated with certain clinical featu-res of HBV related liver disease and Hepatocellu-lar carcinoma. For example Genotype C is associated withlater hepatitis B e antigen(HBe Ag) seroconversion, and more advanced liver disease. Genotype A is associated with a greater risk of progression to chronicity in adu-lt acqu-ired HBV infections. Genotype D is particu-larly associated with the precore mu-tation and HBe Ag negative chronic hepatitis B(CHB). The genotypes prevalent in parts of West Africa, Central and Sou-th America, E, F and H respectively, are less well stu-died. Viral variants especially the Basal Core Promotor mutation is associated with increased risk of fibrosis and cancer of the liver. Althou-gh not cu-rrently part of rou-tine clinical care, evalu-ation of genotype and viral variants may provide u-sefu-l adju-nctive information in predicting risk abou-t liver related morbidity in patients with CHB.展开更多
Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have i...Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.展开更多
It is believed that the degeneration of cholinergic cells in the nucleus basalis of Meynert (NBM) and the loss of cortical cholinergic innervation (cause dementia) of Alzheimer’s disease (AD).~1 (Currently available)...It is believed that the degeneration of cholinergic cells in the nucleus basalis of Meynert (NBM) and the loss of cortical cholinergic innervation (cause dementia) of Alzheimer’s disease (AD).~1 (Currently available) therapeutic interventions are mainly aimed at alleviating the cholinergic deficits. Unfortunately, these strategies do not prevent the disease, but instead offer limited symptomatic improvement.~2 A recent study demonstrated that transplantation of in vitro expanded neural stem cells (NSCs) in an animal model of Parkinson’s disease (PD) resulted in functional recovery of the animals to some extent,~2 suggesting that such neural precursors might offer a useful future therapy for AD. In this study, we tried to find whether mouse embryonic stem (ES) cell derived cholinergic NSCs grafted in the prefrontal and parietal cortex have effects on the disruption of spatial memory following development of lesion in NBM.展开更多
Triple-negative breast cancer(TNBC) is defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2(EGFR2). Most TNBC has a basal-like m...Triple-negative breast cancer(TNBC) is defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2(EGFR2). Most TNBC has a basal-like molecular phenotype by gene expression profiling and shares clinical and pathological features with hereditary BRCA1 related breast cancers. This review evaluates the activity of available chemotherapy and targeted agents in TNBC. A systematic review of PubM ed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with chemotherapy and targeted agents. Our review identified TNBC studies of chemotherapy and targeted agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth and survival pathways. TNBC is sensitive to taxanes and anthracyclins. Platinum agents are effective in TNBC patients with BRCA1 mutation, either alone or in combination with poly adenosine diphosphate polymerase 1 inhibitors. Combinations of ixabepilone and capecitabine have added to progression-free survival(PFS) without survival benefit in metastatic TNBC. Antiangiogenic agents, tyrosine kinase inhibitors and EGFR inhibitorsin combination with chemotherapy produced only modest gains in PFS and had little impact on survival. TNBC subgroups respond differentially to specific targeted agents. In future, the treatment needs to be tailored for a specific patient, depending on the molecular characteristics of their malignancy. TNBC being a chemosensitive entity, combination with targeted agents have not produced substantial improvements in outcomes. Appropriate patient selection with rationale combinations of targeted agents is needed for success.展开更多
Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine （Pinus tabulaeformis） plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling...Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine （Pinus tabulaeformis） plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling region in the middle of Loess Plateau, China. The results indicated that plantation age and season affected soil microbial and enzymatic parameters significantly. Soil organic C, total N, microbial biomass C, microbial quotient, basal respiration, dehydrogenase, N-α-benzoyl-L-argininamide （BAA）-protease, urease and β-glucosidase increased quickly and tended to be highest at PF21 （21-year plantation）, thereafter they remained nearly at a constant level, whereas the metabolic quotient （qCO2） showed an initial increase and then decreased gradually. Measures of these soil properties showed significant seasonal fluctuations except for organic C and total N, which were found to be relatively stable throughout the study period, and the seasonal distributions were autumn 〉 spring 〉 summer 〉 winter for microbial biomass C, microbial quotient, dehydrogenase, and β-glucosidase; autumn 〉 summer 〉 spring 〉 winter for BAA-protease and urease; and summer 〉 autumn 〉 spring 〉 winter for basal respiration and qCO2. Significant season x age interaction was observed for biomass C, basal respiration, dehydrogenase and BAA-protease.展开更多
Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N ...Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.展开更多
能量消耗有多种,如静息能量消耗(resting energy expenditure,REE)、基础能量消耗(basal energy expenditure,BEE)、每日静息能量消耗(resting daily energy expenditure,RDEE)、每日总能量消耗(total daily energy expenditure,TDEE)等。
Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tong...Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tongren in Guizhou Province, Shan- grao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province contained high REE contents in phos- phorites, especially those from Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province. Among them, the highest REE contents reached up to 1361.59×10^-6 and P205 contents up to 29.45%. In contrast, phosphorites from Kaiyang, Qingzhen and Zhenyuan in Guizhou Province had relatively low total REE con- tents and low P205 contents, with the lowest total REE content of 53.19× 10^-6, and the lowest P205 content of 0.07%. REE contents exhibited a positive correlation with phosphorous contents, indicating a close genetic relationship between REE and phosphorous ele- ment. The main reason was the difference of the sedimentary environments and the contents of phosphorous and REE in deep water mass formed in upwelling currents, at an upper slope facies （Slu） in reducing condition due to relatively closed sedimentary environ- ment. It was very difficult for the upswelling phosphorous and REE to deposit, massive phosphorous deposits were hard to be formed. At a deep water ramp facies （DRa） in the ascending process of currents, phosphorus and REE underwent differentiation rather than sedimentation. Consequently, the contents of P205 sediments and REE were low. At a shallow water ramp facies （including shoals and tidal flats） （SRa）, with active seawater circulation and phosphatic supplement, sunny weather, high nutrition and rapid growth of algae, were benefitial for the physical enrichment of carbonate sediments. Therefore, massive phosphorite deposits were easy to be tbrmed with abundant REE minerals, and finally turned into high REE beating phosphorous deposits展开更多
Mg and its alloys have continued to attract interest for several structural and super-sensitive applications because of their light weight and good combination of engineering properties.However for some of these appli...Mg and its alloys have continued to attract interest for several structural and super-sensitive applications because of their light weight and good combination of engineering properties.However for some of these applications,high plastic deformability is required to achieve desired component shapes and configurations;unfortunately,Mg and its alloys have low formability.Scientifically,the plastic behaviour of Mg and its alloys ranks among the most complex and difficult to reconcile in metallic material systems.But basically,the HCP crystal structure coupled with low stacking fault energies(SFE)are largely linked to the poor ductility exhibited by Mg alloys.These innate material characteristics have regrettably limited wide spread applicability of Mg and its alloys.Several research efforts aimed at exploring processing strategies to make these alloys more amenable for high formability–mediated engineering use have been reported and still ongoing.This paper reviews the structural metallurgy of Mg alloys and its influence on mechanical behaviour,specifically,plasticity characteristics.It also concisely presents various processing routes(Alloying,Traditional Forming and Severe Plastic Deformation(SPD))which have been explored to enhance plastic deformability in Mg and its alloys.Grain refinement and homogenising of phases,reducing CRSS between slip modes,twinning suppression to activate non-basal slip,and weakening and randomisation of the basal texture were observed as the formability enhancing strategies explored in the reviewed processes.While identifying the limitations of these strategies,further areas to be explored for enhancing plasticity of Mg alloys are highlighted.展开更多
Land use changes are known to alter soil organic carbon （SOC） and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and mic...Land use changes are known to alter soil organic carbon （SOC） and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and microbial properties in the Changbai Moun- tains of Northeast China is meager. Soil carbon content, microbial biomass carbon （MBC）, basal respiration and soil carbon mineraliza- tion were studied in five selected types of land use： natural old-growth broad-leaved Korean pine mixed forest （NF）; spruce plantation （SP） established following clear-cutting of NF; cropland （CL）; ginseng farmland （GF） previously under NF; and a five-year Mongolian oak young forest （YF） reforested on an abandoned GF, in the Changbai Mountains of Northeast China in 2011. Results showed that SOC content was significantly lower in SP, CL, GF, and YF than in NF. MBC ranged from 304.4 mg/kg in CL to 1350.3 mg/kg in NF, which was significantly higher in the soil of NF than any soil of the other four land use types. The SOC and MBC contents were higher in SP soil than in CL, GF, and YF soils, yielding a significant difference between SP and CL. The value of basal respiration was also higher in NF than in SP, CL, GF, and YF. Simultaneously, higher values of the metabolic quotient were detected in CL, GF, and YF soils, indicat- ing low substrate utilization of the soil microbial community compared with that in NF and SP soil. The values of cumulative mineral- ized carbon and potentially mineralized carbon （Co） in NF were significantly higher than those in CL and GF, while no significant dif- ference was observed between NF and SP. In addition, YF had higher values of Co and C mineralization rate compared with GF. The results indicate that conversion from NF into agricultural land （CL and GF） uses and plantation may lead to a reduction in soil nutrients （SOC and MBC） and substrate utilization efficiency of the microbial community. By contrast, soils below SP were more conducive to the preservation 展开更多
Segmented taper equation was selected to model stem profile of Dahurian larch （Larix gmelinii Rupr.）. The data were based on stem analysis of 74 trees from Dailing Forest Bureau in Heilongjiang Province, Northeaster...Segmented taper equation was selected to model stem profile of Dahurian larch （Larix gmelinii Rupr.）. The data were based on stem analysis of 74 trees from Dailing Forest Bureau in Heilongjiang Province, Northeastern China. Two taper equations with crown ratio and stand basal area were derived from the Max and Burkhart’s （1976） taper equation. Three taper equations were evaluated： （1） the original equation, （2） the original equation with crown ratio, and （3） the original equation with basal area. SAS NLIN and SYSNLIN procedures were used to fit taper equations. Fit statistics and cross-validation were used to evaluate the accuracy and precision of these models. Parameter estimates showed that the original equation with inclusion of crown ratio and basal area variables provided significantly different parameter estimates with lower standard errors. Overall fit statistics indicated that the root mean square error （RMSE） for diameter outside and inside bark decreased respectively by 10% and 7% in the original model with crown ratio and by 12% and 7.2% in the original model with basal area. Cross-validation further confirmed that the original equation with inclusion of crown ratio and basal area variables provided more accurate predictions at the lower section （relative heights, 10%） and upper section （relative heights, 50%） for both outside and inside bark diameters.展开更多
The core promoter(CP) of the viral genome plays an important role for hepatitis B virus(HBV) replication as it directs initiation of transcription for the synthesis of both the precore and pregenomic(pg) RNAs. The CP ...The core promoter(CP) of the viral genome plays an important role for hepatitis B virus(HBV) replication as it directs initiation of transcription for the synthesis of both the precore and pregenomic(pg) RNAs. The CP consists of the upper regulatory region and the basa core promoter(BCP). The CP overlaps with the 3'-end of the X open reading frames and the 5'-end of the precore region,and contains cis-acting elements that can independently direct transcription of the precore mRNA and pgRNA. Its transcription regulation is under strict control of viral and cellular factors. Even though this regulatory region exhibits high sequence conservation,when variations appear,they may contribute to the persistence of HBV within the host,leading to chronic infection and cirrhosis,and eventually,hepatocellular carcinoma. Among CP sequence variations,those occurring at BCP may dysregulate viral gene expression with emphasis in the hepatitis B e antigen,and contribute to disease progression. In this review these molecular aspects and pathologic topics of core promoter are deeply evaluated.展开更多
The purpose of this study is to characterize the re-epithelialization of wound healing in canine prostatic urethra and to evaluate the effect of this re-epithelialization way after two-micron laser resection of the pr...The purpose of this study is to characterize the re-epithelialization of wound healing in canine prostatic urethra and to evaluate the effect of this re-epithelialization way after two-micron laser resection of the prostate （TmLRP）. TmLRP and partial bladder neck mucosa were performed in 15 healthy adult male crossbred canines. Wound specimens were harvested at 3 days, and 1, 2, 3, and 4 weeks after operation, respectively. The histopathologic characteristics were observed by hematoxylin and eosin staining. The expression of cytokeratin 14 （CK14）, CK5, CK18, synaptophysin （Syn）, chromogranin A （CgA）, uroplakin, transforming growth factor-β1 （TGF-β1）, and TGF-β type Ⅱ receptor in prostatic urethra wound were examined by immunohistochemistry and real-time polymerase chain reaction, respectively. Van Gieson staining was performed to determine the expression of collagen fibers in prostatic urethra and bladder neck would. The results showed that the re-epithelialization of the prostatic urethra resulted from the mobilization of proliferating epithelial cells from residual prostate tissue under the wound. The proliferating cells expressed CK14, CK5, but not CK18, Syn, and CgA and re-epithelialize expressed uroplakin since 3 weeks. There were enhanced TGF-β1 and TGF-β type Ⅱ receptor expression in proliferating cells and regenerated cells, which correlated with specific phases of re-epithelialization. Compared with the re-epithelialization of the bladder neck, re-epithelialization of canine prostatic urethra was faster, and the expression of collagen fibers was relatively low. In conclusion, re-epithelialization in canine prostatic urethra resulted from prostate basal cells after TmLRP and this re-epithelialization way may represent the ideal healing method from anatomic repair to functional recovery after injury.展开更多
Background: Due to advances in high-frequency ultrasound technology, it is easier to detect fine structures of skin lesions. The aim of this study was to examine the ultrasonographic features and use recurrence risk s...Background: Due to advances in high-frequency ultrasound technology, it is easier to detect fine structures of skin lesions. The aim of this study was to examine the ultrasonographic features and use recurrence risk stratification to assess the diagnostic performance of pre-operative ultrasound examination of basal cell carcinoma (BCC). Methods: This was a retrospective study. Forty-six BCC lesions underwent pre-operative ultrasound examination using 50- and 20- MHz probes. Ultrasonographic shape, margin, internal echoes, hyper-echoic spots, posterior echoes, and depth of the lesion were evaluated and correlated with the risk of recurrence based on histological features. Results: Forty-two patients had 46 skin lesions in total. The high-risk (n = 6) and low-risk (n = 40) groups exhibited considerable overlap in the ultrasonographic manifestations and no significant difference in margin (χ^2 = 3.231, P = 0.072), internal echo (χ^2 = 1.592, P = 0.207), or posterior echo (P = 0.169). However, high-risk BCCs tended to be irregular in shape than low-risk lesions (χ^2 = 4.313, P = 0.038). Both types presented hyper-echoic spots (χ^2 = 1.850, P = 0.174). Additionally, 78% of low-risk lesions were confined to the dermis (31/40), and 100% of high-risk lesions infiltrated into the sub-cutaneous tissue, resulting in a significant difference between the two groups (χ^2 = 10.951, P = 0.001). Ultrasound detected sub-clinical lesions in five patients. Conclusions: High-frequency ultrasound can provide important information for pre-operative evaluation of risk in BCC foci and reveal hidden lesions. The technique may play a crucial role in guiding therapeutic options for BCC.展开更多
基金This work was supported by the Chinese Academy of Sciences （CEMPS2016009 XDA08020203）, the Ministry of Science and Technology of China （2013CB127002 2016YFD0102102）, and the National Natural Science Foundation of China （31571635）.
文摘Breeding semi-dwarf varieties to improve lodging resistance has been proven to be enormously successful in increasing grain yield since the advent of the ＂green revolution.＂ However, the breeding of the majority of semi-dwarf rice varieties in Asia has been dependent mainly on genetic introduction of the mutant alleles of SD1, which encodes a gibberellin （GA） 20-oxidase, OsGA20ox2, for catalyzing GA biosynthesis. Here, we report a new rice lodging-resistance gene, Shortened Basal lnternodes （SBI）, which encodes a gibberellin 2- oxidase and specifically controls the elongation of culm basal internodes through deactivating GA activity. SBI is predominantly expressed in culm basal internodes. Genetic analyses indicate that SBI is a semidominant gene affecting rice height and lodging resistance. SBI allelic variants display different activities and are associated with the height of rice varieties. Breeding with higher activity of the SBI allele generates new rice varieties with improved lodging resistance and increased yield. The discovery of the SB! provides a desirable gene resource for producing semi-dwarf rice phenotypes and offers an effective strategy for breeding rice varieties with enhanced lodging resistance and high yield.
基金Supported by the National Basic Research Program (973 Program) of China (No. 2006CB403206)the Key Project in the NationalScience & Technology Pillar Program in the Eleventh Five-year Plan Period of China (Nos. 2006BAC01A09 and 2006BAD03A1006)National Natural Science Foundation of China (No. 30872076)
文摘The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic variation associated with vegetation restoration and further to explore the role of soil microbiology in vegetation restoration mechanism of degraded karst regions,we measured microbial biomass C and basal respiration in soils during vegetation restoration in Zhenfeng County of southwestern Guizhou Province,China.The community level physiological profiles(CLPP) of the soil microbial community to were estimated determine if vegetation changes were accompanied by changes in functioning of soil microbial communities.The results showed that soil microbial biomass C and microbial quotient(microbial biomass C/organic C) tended to increase with vegetation restoration,being in the order arboreal community stage > shrubby community stage > herbaceous community stage > bare land stage.Similar trend was found in the change of basal respiration(BR).The metabolic quotient(the ratio of basal respiration to microbial biomass,qCO 2) decreased with vegetation restoration,and remained at a constantly low level in the arboreal community stage.Analyses of the CLPP data indicated that vegetation restoration tended to result in higher average well color development,substrate richness,and functional diversity.Average utilization of specific substrate guilds was highest in the arboreal community stage.Principle component analysis of the CLPP data further indicated that the arboreal community stage was distinctly different from the other three stages.In conclusion,vegetation restoration improved soil microbial biomass C,respiration,and utilization of carbon sources,and decreased qCO 2,thus creating better soil conditions,which in turn could promote the restoration of vegetation on degraded karst regions.
基金supported by the National Natural Science Foundation of China(41130314,91014003)Chinese Academy of Sciences Innovation(Y42217101L),grants from Regional and Local Authorities(Shandong Province and City of Qingdao)+1 种基金supported by National Oceanography Laboratory in Qingdaosupported by the National Natural Science Foundation of China(NSFC)
文摘The effect of paleo-Pacific subduction on the geological evolution of the western Pacific and continental China is likely complex. Nevertheless, our analysis of the distribution of Mesozoic granitoids in the eastern continental China in space and time has led us to an interesting conclusion： The basement of the continental shelf beneath East and South China Seas may actually be of exotic origin geologically unrelated to the continental lithosphere of eastern China. By accepting the notion that the Jurassic- Cretaceous granitoids in the region are genetically associated with western Pacific subduction and the concept that subduction may cease to continue only if the trench is being jammed, then the termination of the granitoid magmatism throughout the vast region at -88±2 Ma manifests the likelihood of ＂sudden＂, or shortly beforehand （- 100 Ma）, trench jam of the Mesozoic western Pacific subduction. Trench jam happens if the incoming ＂plate＂ or portion of the plate contains a sizeable mass that is too buoyant to subduct. The best candidate for such a buoyant and unsubductable mass is either an oceanic plateau or a micro-continent. We hypothesize that the basement of the Chinese continental shelf represents such an exotic, buoyant and unsubductable mass, rather than seaward extension of the continental lithosphere of eastern China. The locus of the jammed trench （i.e., the suture） is predictably located on the shelf in the vicinity of, and parallel to, the arc-curved coastal line of the southeast continental China. It is not straightforward to locate the locus in the northern section of the East China Sea shelf because of the more recent （〈20 Ma） tectonic re-organization associated with the opening of the Sea of Japan. We predict that the trench jam at - 100 Ma led to the re-orientation of the Pacific plate motion in the course of NNW direction as inferred from the age-progressive Emperor Seamount Chain of Hawaiian hotspot origin （its oldest unsubdued Meiji and Detroit seamounts are -82 M
文摘This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance （CRF1） and polymer materials （CRF3） increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer （RSF1）. Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.
文摘Objective： To investigate brain activity patterns during acupuncture in stroke patients, and to compare the result with normal subjects using functional magnetic resonance imaging （fMRI）. Methods： A total of 11 stroke patients with motor weakness and 10 healthy subjects were studied, fMRI was performed during acupuncture on the left side at points Quchi （Llll） and Zusanli （ST36）. Data were analyzed using statistical parametric maps of brain activation induced by acupuncture stimulation. Results： The results showed that stimulation of both LI11 and ST36 produced significantly different brain activation patterns between the two groups. The normal group showed a greater overall activation than the stroke group. In the normal group, parts of the frontal lobe, parietal lobe, sub-lobar, cerebellum and midbrain regions were activated by acupuncture at the left LI11. On the other hand, only the right side of the inferior parietal Iobule region was activated in the stroke patients. When the left ST36 was stimulated in the normal group, both sides of the frontal lobe, parietal lobe, temporal lobe, and sub-lobar, and the left side of occipital lobe, and the right side of cerebellum and midbrain regions were activated. For the same stimulation in the stroke group, only both sides of the inferior parietal Iobule and cerebellum regions were activated （P〈0.05, cluster level）. Deactivation pattern was not noted during any acupuncture stimulation in both groups. Conclusion： Brain signal activations during the same acupuncture were different between the healthy and the stroke patients, and the effects showed a correlation of different acupuncture points.
基金This work was supported by the grants from the Beijing Natural Science Foundation （No. 7091006）, the National Key Basic Research Developing Project （No. 2007CB512803）, and the National 11th Five-Year Special Grand Project for Infectious Diseases （No. 2008ZX10002-011 and No. 2009ZX10004-314）. Conflict of interests： None.
文摘Background There is still a paucity of data on hepatitis B virus （HBV） subgenotype prevalence in North China based on sequencing of large-size samples. In addition, whether HBV genotypes impact drug-resistance-associated and HBV e antigen （HBeAg）-Ioss-associated mutations in patients with chronic hepatitis B （CHB） is still under investigation. This study aimed to disclose clinical prevalence of HBV genotypes/subgenotypes in North China and the clinical implications of HBV genotype classification in respect to HBeAg loss and drug-resistant occurrence. Methods Sera were collected from 1301 nucleos（t）ide analog-experienced CHB patients. Viral DNA was extracted and used as template for HBV genome amplification by nested PCR. DNA sequencing was performed for the analysis of HBV genotypes/subgenotypes, drug-resistance-associated mutations in polymerase gene and HBeAg-loss-associated mutations in precore/basal core promoter （BCP） regions. Results HBV/B, HBV/C, and HBV/D were detected in 190 （14.6%）, 1096 （84.2%）, and 15 （1.2%） patients, respectively. HBV/B2 （182/190）, HBV/C2 （1069/1096）, and HBV/D1 （12/15） were predominant subgenotypes within individual genotypes. By contrast, C2 prevalence is relatively lower in Beijing area （77.2%） than in other north areas （84.9%-87.4%）. HBV/C-infected patients had an older age and a lower serum albumin level but similar HBV DNA and alanine aminotransferase （ALT） levels compared to HBV/B-infected patients. HBV/C infection had a higher incidence of lamivudine-resistant mutations rtM2041N （44.9% vs. 30.2%, P 〈0.01） and BCP mutations A1762T＋G1764A （65.8% vs. 40.0%, P〈0.01） compared with HBV/B infection. Conclusions C2 is the most prevalent HBV subgenotype followed by B2 in CHB patients in North China; and HBV genotype prevalence is influenced by immigrant population. HBV/C infection is likely to have longer disease duration and severer liver functional impairment and might be more susceptible to develop lamivudine res
文摘The Hepatitis B Virus(HBV) has a worldwide distribu-tion and is endemic in many populations. It is constantly evolving and 10 genotypic strains have been identified with varying prevalences in different geographic regions. Numerous stable mutations in the core gene and in the su-rface gene of the HBV have also been identified in untreated HBV populations. The genotypes and viral variants have been associated with certain clinical featu-res of HBV related liver disease and Hepatocellu-lar carcinoma. For example Genotype C is associated withlater hepatitis B e antigen(HBe Ag) seroconversion, and more advanced liver disease. Genotype A is associated with a greater risk of progression to chronicity in adu-lt acqu-ired HBV infections. Genotype D is particu-larly associated with the precore mu-tation and HBe Ag negative chronic hepatitis B(CHB). The genotypes prevalent in parts of West Africa, Central and Sou-th America, E, F and H respectively, are less well stu-died. Viral variants especially the Basal Core Promotor mutation is associated with increased risk of fibrosis and cancer of the liver. Althou-gh not cu-rrently part of rou-tine clinical care, evalu-ation of genotype and viral variants may provide u-sefu-l adju-nctive information in predicting risk abou-t liver related morbidity in patients with CHB.
文摘Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.
文摘It is believed that the degeneration of cholinergic cells in the nucleus basalis of Meynert (NBM) and the loss of cortical cholinergic innervation (cause dementia) of Alzheimer’s disease (AD).~1 (Currently available) therapeutic interventions are mainly aimed at alleviating the cholinergic deficits. Unfortunately, these strategies do not prevent the disease, but instead offer limited symptomatic improvement.~2 A recent study demonstrated that transplantation of in vitro expanded neural stem cells (NSCs) in an animal model of Parkinson’s disease (PD) resulted in functional recovery of the animals to some extent,~2 suggesting that such neural precursors might offer a useful future therapy for AD. In this study, we tried to find whether mouse embryonic stem (ES) cell derived cholinergic NSCs grafted in the prefrontal and parietal cortex have effects on the disruption of spatial memory following development of lesion in NBM.
文摘Triple-negative breast cancer(TNBC) is defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2(EGFR2). Most TNBC has a basal-like molecular phenotype by gene expression profiling and shares clinical and pathological features with hereditary BRCA1 related breast cancers. This review evaluates the activity of available chemotherapy and targeted agents in TNBC. A systematic review of PubM ed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with chemotherapy and targeted agents. Our review identified TNBC studies of chemotherapy and targeted agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth and survival pathways. TNBC is sensitive to taxanes and anthracyclins. Platinum agents are effective in TNBC patients with BRCA1 mutation, either alone or in combination with poly adenosine diphosphate polymerase 1 inhibitors. Combinations of ixabepilone and capecitabine have added to progression-free survival(PFS) without survival benefit in metastatic TNBC. Antiangiogenic agents, tyrosine kinase inhibitors and EGFR inhibitorsin combination with chemotherapy produced only modest gains in PFS and had little impact on survival. TNBC subgroups respond differentially to specific targeted agents. In future, the treatment needs to be tailored for a specific patient, depending on the molecular characteristics of their malignancy. TNBC being a chemosensitive entity, combination with targeted agents have not produced substantial improvements in outcomes. Appropriate patient selection with rationale combinations of targeted agents is needed for success.
基金Supported by the National Natural Science Foundation of China (Nos. 41171154 and 41021091)the National KeyTechnologies R&D Program of China (Nos. 2011BAK12B05 and 2011BAK12B08)+2 种基金the Program for New Century ExcellentTalents in University (No. NECT-09-0449)the Discipline Innovation S&T Program in Higher Learning Institutions(111 Program)the Ministry of Education & the State Administration of Foreign Experts Affairs, China (No. B06026)
文摘Successional and seasonal effects on soil microbial and enzymatic properties were studied in Chinese pine （Pinus tabulaeformis） plantations in an age sequence of 3-, 7-, 13-, 21- and 28-year-old in northern Ziwuling region in the middle of Loess Plateau, China. The results indicated that plantation age and season affected soil microbial and enzymatic parameters significantly. Soil organic C, total N, microbial biomass C, microbial quotient, basal respiration, dehydrogenase, N-α-benzoyl-L-argininamide （BAA）-protease, urease and β-glucosidase increased quickly and tended to be highest at PF21 （21-year plantation）, thereafter they remained nearly at a constant level, whereas the metabolic quotient （qCO2） showed an initial increase and then decreased gradually. Measures of these soil properties showed significant seasonal fluctuations except for organic C and total N, which were found to be relatively stable throughout the study period, and the seasonal distributions were autumn 〉 spring 〉 summer 〉 winter for microbial biomass C, microbial quotient, dehydrogenase, and β-glucosidase; autumn 〉 summer 〉 spring 〉 winter for BAA-protease and urease; and summer 〉 autumn 〉 spring 〉 winter for basal respiration and qCO2. Significant season x age interaction was observed for biomass C, basal respiration, dehydrogenase and BAA-protease.
基金financial support from theNational Natural Science Foundation of China (31471443, 31501262)the Fundamental Research Funds for the Central Universities, China (KJQN201632)the Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University
文摘Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.
文摘能量消耗有多种,如静息能量消耗(resting energy expenditure,REE)、基础能量消耗(basal energy expenditure,BEE)、每日静息能量消耗(resting daily energy expenditure,RDEE)、每日总能量消耗(total daily energy expenditure,TDEE)等。
基金Project supported by National Natural Science Foundation of China(50164001)the State Programs of Science and Technology Development funded by The Ministry of Science and Technology of China(2007BAB08B03)+3 种基金the Outstanding Scientific and Technological Talents Fund of Guizhou Province(2009008)the Graduates Innovation Fund of Guizhou University(2010009)the Youth Fund of Guizhou University(2009070)the Youth Fund of College of Resources and Environmental Engineering,Guizhou University(ZHY0901)
文摘Analysis on P205 and REE （rare earth elements） in basal Cambrian phosphorites from the Yangtze Region, showed that the phosphorites from Bailongtan in Yunnan Province, Zhijin, Jinsha, Xishui, Zunyi, Tianzhu and Tongren in Guizhou Province, Shan- grao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province contained high REE contents in phos- phorites, especially those from Tianzhu and Tongren in Guizhou Province, Shangrao in Jiangxi Province, Jiangshan in Zhejiang Province and Nanjing in Jiangsu Province. Among them, the highest REE contents reached up to 1361.59×10^-6 and P205 contents up to 29.45%. In contrast, phosphorites from Kaiyang, Qingzhen and Zhenyuan in Guizhou Province had relatively low total REE con- tents and low P205 contents, with the lowest total REE content of 53.19× 10^-6, and the lowest P205 content of 0.07%. REE contents exhibited a positive correlation with phosphorous contents, indicating a close genetic relationship between REE and phosphorous ele- ment. The main reason was the difference of the sedimentary environments and the contents of phosphorous and REE in deep water mass formed in upwelling currents, at an upper slope facies （Slu） in reducing condition due to relatively closed sedimentary environ- ment. It was very difficult for the upswelling phosphorous and REE to deposit, massive phosphorous deposits were hard to be formed. At a deep water ramp facies （DRa） in the ascending process of currents, phosphorus and REE underwent differentiation rather than sedimentation. Consequently, the contents of P205 sediments and REE were low. At a shallow water ramp facies （including shoals and tidal flats） （SRa）, with active seawater circulation and phosphatic supplement, sunny weather, high nutrition and rapid growth of algae, were benefitial for the physical enrichment of carbonate sediments. Therefore, massive phosphorite deposits were easy to be tbrmed with abundant REE minerals, and finally turned into high REE beating phosphorous deposits
文摘Mg and its alloys have continued to attract interest for several structural and super-sensitive applications because of their light weight and good combination of engineering properties.However for some of these applications,high plastic deformability is required to achieve desired component shapes and configurations;unfortunately,Mg and its alloys have low formability.Scientifically,the plastic behaviour of Mg and its alloys ranks among the most complex and difficult to reconcile in metallic material systems.But basically,the HCP crystal structure coupled with low stacking fault energies(SFE)are largely linked to the poor ductility exhibited by Mg alloys.These innate material characteristics have regrettably limited wide spread applicability of Mg and its alloys.Several research efforts aimed at exploring processing strategies to make these alloys more amenable for high formability–mediated engineering use have been reported and still ongoing.This paper reviews the structural metallurgy of Mg alloys and its influence on mechanical behaviour,specifically,plasticity characteristics.It also concisely presents various processing routes(Alloying,Traditional Forming and Severe Plastic Deformation(SPD))which have been explored to enhance plastic deformability in Mg and its alloys.Grain refinement and homogenising of phases,reducing CRSS between slip modes,twinning suppression to activate non-basal slip,and weakening and randomisation of the basal texture were observed as the formability enhancing strategies explored in the reviewed processes.While identifying the limitations of these strategies,further areas to be explored for enhancing plasticity of Mg alloys are highlighted.
基金Under the auspices of National Key Technology Research and Development Program of China(No.2012BAD22B04)CFERN&GENE Award Funds on Ecological PaperNational Natural Science Foundation of China(No.30900208)
文摘Land use changes are known to alter soil organic carbon （SOC） and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and microbial properties in the Changbai Moun- tains of Northeast China is meager. Soil carbon content, microbial biomass carbon （MBC）, basal respiration and soil carbon mineraliza- tion were studied in five selected types of land use： natural old-growth broad-leaved Korean pine mixed forest （NF）; spruce plantation （SP） established following clear-cutting of NF; cropland （CL）; ginseng farmland （GF） previously under NF; and a five-year Mongolian oak young forest （YF） reforested on an abandoned GF, in the Changbai Mountains of Northeast China in 2011. Results showed that SOC content was significantly lower in SP, CL, GF, and YF than in NF. MBC ranged from 304.4 mg/kg in CL to 1350.3 mg/kg in NF, which was significantly higher in the soil of NF than any soil of the other four land use types. The SOC and MBC contents were higher in SP soil than in CL, GF, and YF soils, yielding a significant difference between SP and CL. The value of basal respiration was also higher in NF than in SP, CL, GF, and YF. Simultaneously, higher values of the metabolic quotient were detected in CL, GF, and YF soils, indicat- ing low substrate utilization of the soil microbial community compared with that in NF and SP soil. The values of cumulative mineral- ized carbon and potentially mineralized carbon （Co） in NF were significantly higher than those in CL and GF, while no significant dif- ference was observed between NF and SP. In addition, YF had higher values of Co and C mineralization rate compared with GF. The results indicate that conversion from NF into agricultural land （CL and GF） uses and plantation may lead to a reduction in soil nutrients （SOC and MBC） and substrate utilization efficiency of the microbial community. By contrast, soils below SP were more conducive to the preservation
基金This study was supported by the National Natural Science Foundation of China(30972363)Special Fund for For-estry-Scientific Research in the Public Interest(201004026)+2 种基金China Postdoctoral Science Foundation(200902362,20100471014)the Fun-damental Research Funds for the Central Universities(DL10CA06)SRF for ROCS,SEM.
文摘Segmented taper equation was selected to model stem profile of Dahurian larch （Larix gmelinii Rupr.）. The data were based on stem analysis of 74 trees from Dailing Forest Bureau in Heilongjiang Province, Northeastern China. Two taper equations with crown ratio and stand basal area were derived from the Max and Burkhart’s （1976） taper equation. Three taper equations were evaluated： （1） the original equation, （2） the original equation with crown ratio, and （3） the original equation with basal area. SAS NLIN and SYSNLIN procedures were used to fit taper equations. Fit statistics and cross-validation were used to evaluate the accuracy and precision of these models. Parameter estimates showed that the original equation with inclusion of crown ratio and basal area variables provided significantly different parameter estimates with lower standard errors. Overall fit statistics indicated that the root mean square error （RMSE） for diameter outside and inside bark decreased respectively by 10% and 7% in the original model with crown ratio and by 12% and 7.2% in the original model with basal area. Cross-validation further confirmed that the original equation with inclusion of crown ratio and basal area variables provided more accurate predictions at the lower section （relative heights, 10%） and upper section （relative heights, 50%） for both outside and inside bark diameters.
文摘The core promoter(CP) of the viral genome plays an important role for hepatitis B virus(HBV) replication as it directs initiation of transcription for the synthesis of both the precore and pregenomic(pg) RNAs. The CP consists of the upper regulatory region and the basa core promoter(BCP). The CP overlaps with the 3'-end of the X open reading frames and the 5'-end of the precore region,and contains cis-acting elements that can independently direct transcription of the precore mRNA and pgRNA. Its transcription regulation is under strict control of viral and cellular factors. Even though this regulatory region exhibits high sequence conservation,when variations appear,they may contribute to the persistence of HBV within the host,leading to chronic infection and cirrhosis,and eventually,hepatocellular carcinoma. Among CP sequence variations,those occurring at BCP may dysregulate viral gene expression with emphasis in the hepatitis B e antigen,and contribute to disease progression. In this review these molecular aspects and pathologic topics of core promoter are deeply evaluated.
文摘The purpose of this study is to characterize the re-epithelialization of wound healing in canine prostatic urethra and to evaluate the effect of this re-epithelialization way after two-micron laser resection of the prostate （TmLRP）. TmLRP and partial bladder neck mucosa were performed in 15 healthy adult male crossbred canines. Wound specimens were harvested at 3 days, and 1, 2, 3, and 4 weeks after operation, respectively. The histopathologic characteristics were observed by hematoxylin and eosin staining. The expression of cytokeratin 14 （CK14）, CK5, CK18, synaptophysin （Syn）, chromogranin A （CgA）, uroplakin, transforming growth factor-β1 （TGF-β1）, and TGF-β type Ⅱ receptor in prostatic urethra wound were examined by immunohistochemistry and real-time polymerase chain reaction, respectively. Van Gieson staining was performed to determine the expression of collagen fibers in prostatic urethra and bladder neck would. The results showed that the re-epithelialization of the prostatic urethra resulted from the mobilization of proliferating epithelial cells from residual prostate tissue under the wound. The proliferating cells expressed CK14, CK5, but not CK18, Syn, and CgA and re-epithelialize expressed uroplakin since 3 weeks. There were enhanced TGF-β1 and TGF-β type Ⅱ receptor expression in proliferating cells and regenerated cells, which correlated with specific phases of re-epithelialization. Compared with the re-epithelialization of the bladder neck, re-epithelialization of canine prostatic urethra was faster, and the expression of collagen fibers was relatively low. In conclusion, re-epithelialization in canine prostatic urethra resulted from prostate basal cells after TmLRP and this re-epithelialization way may represent the ideal healing method from anatomic repair to functional recovery after injury.
文摘Background: Due to advances in high-frequency ultrasound technology, it is easier to detect fine structures of skin lesions. The aim of this study was to examine the ultrasonographic features and use recurrence risk stratification to assess the diagnostic performance of pre-operative ultrasound examination of basal cell carcinoma (BCC). Methods: This was a retrospective study. Forty-six BCC lesions underwent pre-operative ultrasound examination using 50- and 20- MHz probes. Ultrasonographic shape, margin, internal echoes, hyper-echoic spots, posterior echoes, and depth of the lesion were evaluated and correlated with the risk of recurrence based on histological features. Results: Forty-two patients had 46 skin lesions in total. The high-risk (n = 6) and low-risk (n = 40) groups exhibited considerable overlap in the ultrasonographic manifestations and no significant difference in margin (χ^2 = 3.231, P = 0.072), internal echo (χ^2 = 1.592, P = 0.207), or posterior echo (P = 0.169). However, high-risk BCCs tended to be irregular in shape than low-risk lesions (χ^2 = 4.313, P = 0.038). Both types presented hyper-echoic spots (χ^2 = 1.850, P = 0.174). Additionally, 78% of low-risk lesions were confined to the dermis (31/40), and 100% of high-risk lesions infiltrated into the sub-cutaneous tissue, resulting in a significant difference between the two groups (χ^2 = 10.951, P = 0.001). Ultrasound detected sub-clinical lesions in five patients. Conclusions: High-frequency ultrasound can provide important information for pre-operative evaluation of risk in BCC foci and reveal hidden lesions. The technique may play a crucial role in guiding therapeutic options for BCC.
