AIM: To investigate the expression of NDRG2 and mutation of the entire coding region of NDRG2 in human liver and pancreatic cancers, and to further discuss the possible causes of NDRG2 distinct expression patterns.MET...AIM: To investigate the expression of NDRG2 and mutation of the entire coding region of NDRG2 in human liver and pancreatic cancers, and to further discuss the possible causes of NDRG2 distinct expression patterns.METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze the expression of NDRG2 mRNA in 37 fresh cancer specimens (including 8 cases of pancreatic cancer and 29 cases of liver cancer) and adjacent normal tissues collected from clinical operation. In addition,mutation analysis of the whole coding region of NDRG2 in these cancers was examined by polymerase chain reactionsingle strand conformational polymorphism (PCR-SSCP).RESULTS: Compared with adjacent normal tissues, the expression levels of NDRG2 mRNA in corresponding cancer tissues reduced significantly (pancreatic cancer: 0.680±0.112 vs 2.089±0.214, P<0.01) (liver cancer: 0.894±0.098 vs 1.345±0.177, P<0.05). Using PCR-SSCP, the mutation of the whole coding region of NDRG2 was not found in those cancer tissues where the expression of NDRG2 mRNA reduced markedly.CONCLUSION: NDRG2 gene might express differently between normal tissues and cancer tissues, and might play an important role in the development of pancreatic cancer and liver cancer. Low expression of NDRG2 might be unrelated to the mutation of coding region of NDRG2.展开更多
To study the inhibitory effect of Huqi San （Qi- protecting powder） on rat prehepatocarcinoma induced by diethylinitrosamine （DEN） by analyzing the mutational activation of c-fos proto-oncogene and over-expression ...To study the inhibitory effect of Huqi San （Qi- protecting powder） on rat prehepatocarcinoma induced by diethylinitrosamine （DEN） by analyzing the mutational activation of c-fos proto-oncogene and over-expression of c-jun and c-myc oncogenes. METHODS： A Solt-Farber two-step test model of prehepatocarcinoma was induced in rats by DEN and 2-acetylaminofluorene （AAF） to investigate the modifying effects of Huqi San on the expression of c-jun, c-fos and c-myc in DEN-mediated hepatocarcinogenesis. Huqi San was made of eight medicinal herbs containing glycoprival granules, in which each milliliter contains 0.38 g crude drugs. T-glutamy-transpeptidase-isoenzyme （T-GTase） was determined with histochemical methods. Level of 8-hydroxydeoxyguanosine （OHdG） formed in liver and c-jun, c-fos and c-myc proto-oncogenes were detected by immunohistochemical methods. RESULTS： The level of 8-OHdG, a mark of oxidative DNA damage, was significantly decreased in the liver of rats with prehepatocarcinoma induced by DEN who received 8 g/kg body weight or 4 g/kg body weight Huqi San before （1 wk） and after DEN exposure （4 wk）. Huqi San- treated rats showed a significant decrease in number of T-GT positive foci （P 〈 0.001, prevention group： 4.96-0.72 vs 29.46-2.17; large dose therapeutic group： 7.53-0.88 vs 29.46-2.17）. On the other hand, significant changes in expression of c-jun, c-fos and c-myc were found in Huqi San-treated rats. CONCLUSION： Activation of c-jun, c-fos and c-myc plays a crucial role in the pathogenesis of liver cancer.Huqi San can inhibit the over-expression of c-jun, c-fos and c-myc oncogenes and liver preneolastic lesions induced by DEN.展开更多
Dear Editor,RNA knockdown in vivo carries significant potential for dis-ease modeling and therapies.Despite the emerging approaches of CRISPR/Cas9-mediated permanent knock out of targeted genes,strategies targeting RN...Dear Editor,RNA knockdown in vivo carries significant potential for dis-ease modeling and therapies.Despite the emerging approaches of CRISPR/Cas9-mediated permanent knock out of targeted genes,strategies targeting RNA for disruption are advantageous in the treatment of acquired metabolic disorders when permanent modification of genome DNA is not appropriate,and RNA virus infection diseases when pathogenic DNA is not available(such as SARS-Cov-2 and MERS infections).展开更多
Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)rema...Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)remains unclear.Here,we performed a genome-wide association study and linkage mapping to dissect the genetic basis of seed dormancy in rice.Our findings suggest that Seed Dormancy4(Sdr4),a central modulator of seed dormancy,integrates the abscisic acid and gibberellic acid signaling pathways at the transcriptional level.Haplotype analysis revealed that three Sdr4 alleles in rice cultivars already existed in ancestral Oryza rufipogon accessions.Furthermore,like the semi-dwarf 1(SD1)and Rc loci,Sdr4 underwent selection during the domestication and improvement of Asian cultivated rice.The distribution frequency of the Sdr4-n allele in different locations in Asia is negatively associated with local annual temperature and precipitation.Finally,we developed functional molecular markers for Sdr4,SD1,and Rc for use in molecular breeding.Our results provide clues about the molecular basis of Sdr4-regulated seed dormancy.Moreover,these findings provide guidance for utilizing the favorable alleles of Sdr4 and Rc to synergistically boost PHS resistance,yield,and quality in modern rice varieties.展开更多
A high performance liquid chromatography-ultraviolet(HPLC-UV)fingerprint method for the overall chemical analysis of edible mushrooms was established based on Auricularia heimuer for the first time,and then applied to...A high performance liquid chromatography-ultraviolet(HPLC-UV)fingerprint method for the overall chemical analysis of edible mushrooms was established based on Auricularia heimuer for the first time,and then applied to analyze 60 batches of A.heimuer,Auricularia cornea.Auricularia cornea*Yu Muer’and TremeUa fuciformis.A total of 9 characteristic peaks of A.heimuer.11 characteristic peaks of A.cornea,6 characteristic peaks of A.cornea‘Yu Muer’,and 9 characteristic peaks of I fuciformis were designated.Then,a combinatory analysis,including similarity evaluation,hierarchical cluster analysis and principal component analysis,revealed the chemical consistency and difference between samples from the same and different species.The HPLC fingerprint method established in this paper could be used to characterize the components of A.heimuer,A.cornea,A.cornea‘Yu Muer’,and T.fuciformis and discriminate the 4 edible mushrooms effectively in combination with pattern recognition analysis.展开更多
Postoperative tumor recurrence remains a predominant cause of treatment failure. In this study, we developed an in situ injectable hydrogel, termed MPB-NO@DOX + ATRA gel, which was locally formed within the tumor rese...Postoperative tumor recurrence remains a predominant cause of treatment failure. In this study, we developed an in situ injectable hydrogel, termed MPB-NO@DOX + ATRA gel, which was locally formed within the tumor resection cavity. The MPB-NO@DOX + ATRA gel was fabricated by mixing a thrombin solution, a fibrinogen solution containing all-trans retinoic acid (ATRA), and a Mn/NO-based immune nano-activator termed MPB-NO@DOX. ATRA promoted the differentiation of cancer stem cells, inhibited cancer cell migration, and affected the polarization of tumor-associated macrophages. The outer MnO2 shell disintegrated due to its reaction with glutathione and hydrogen peroxide in the cytoplasm to release Mn2+ and produce O2, resulting in the release of doxorubicin (DOX). The released DOX entered the nucleus and destroyed DNA, and the fragmented DNA cooperated with Mn2+ to activate the cGAS-STING pathway and stimulate an anti-tumor immune response. In addition, when MPB-NO@DOX was exposed to 808 nm laser irradiation, the Fe-NO bond was broken to release NO, which downregulated the expression of PD-L1 on the surface of tumor cells and reversed the immunosuppressive tumor microenvironment. In conclusion, the MPB-NO@DOX + ATRA gel exhibited excellent anti-tumor efficacy. The results of this study demonstrated the great potential of in situ injectable hydrogels in preventing postoperative tumor recurrence.展开更多
Mahjong,a complex game with hidden information and sparse rewards,poses significant challenges.Existing Mahjong AIs require substantial hardware resources and extensive datasets to enhance AI capabilities.The authors ...Mahjong,a complex game with hidden information and sparse rewards,poses significant challenges.Existing Mahjong AIs require substantial hardware resources and extensive datasets to enhance AI capabilities.The authors propose a transformer‐based Mahjong AI(Tjong)via hierarchical decision‐making.By utilising self‐attention mechanisms,Tjong effectively captures tile patterns and game dynamics,and it decouples the decision pro-cess into two distinct stages:action decision and tile decision.This design reduces de-cision complexity considerably.Additionally,a fan backward technique is proposed to address the sparse rewards by allocating reversed rewards for actions based on winning hands.Tjong consists of 15M parameters and is trained using approximately 0.5 M data over 7 days of supervised learning on a single server with 2 GPUs.The action decision achieved an accuracy of 94.63%,while the claim decision attained 98.55%and the discard decision reached 81.51%.In a tournament format,Tjong outperformed AIs(CNN,MLP,RNN,ResNet,VIT),achieving scores up to 230%higher than its opponents.Further-more,after 3 days of reinforcement learning training,it ranked within the top 1%on the leaderboard on the Botzone platform.展开更多
The game of Tibetan Go faces the scarcity of expert knowledge and research literature.Therefore,we study the zero learning model of Tibetan Go under limited computing power resources and propose a novel scaleinvariant...The game of Tibetan Go faces the scarcity of expert knowledge and research literature.Therefore,we study the zero learning model of Tibetan Go under limited computing power resources and propose a novel scaleinvariant U-Net style two-headed output lightweight network TibetanGoTinyNet.The lightweight convolutional neural networks and capsule structure are applied to the encoder and decoder of TibetanGoTinyNet to reduce computational burden and achieve better feature extraction results.Several autonomous self-attention mechanisms are integrated into TibetanGoTinyNet to capture the Tibetan Go board’s spatial and global information and select important channels.The training data are generated entirely from self-play games.TibetanGoTinyNet achieves 62%–78%winning rate against other four U-Net style models including Res-UNet,Res-UNet Attention,Ghost-UNet,and Ghost Capsule-UNet.It also achieves 75%winning rate in the ablation experiments on the attention mechanism with embedded positional information.The model saves about 33%of the training time with 45%–50%winning rate for different Monte–Carlo tree search(MCTS)simulation counts when migrated from 9×9 to 11×11 boards.Code for our model is available at https://github.com/paulzyy/TibetanGoTinyNet.展开更多
To tackle the problem of aquatic environment pollution,a vision-based autonomous underwater garbage cleaning robot has been developed in our laboratory.We propose a garbage detection method based on a modified YOLOv4,...To tackle the problem of aquatic environment pollution,a vision-based autonomous underwater garbage cleaning robot has been developed in our laboratory.We propose a garbage detection method based on a modified YOLOv4,allowing high-speed and high-precision object detection.Specifically,the YOLOv4 algorithm is chosen as a basic neural network framework to perform object detection.With the purpose of further improvement on the detection accuracy,YOLOv4 is transformed into a four-scale detection method.To improve the detection speed,model pruning is applied to the new model.By virtue of the improved detection methods,the robot can collect garbage autonomously.The detection speed is up to 66.67 frames/s with a mean average precision(mAP)of 95.099%,and experimental results demonstrate that both the detection speed and the accuracy of the improved YOLOv4 are excellent.展开更多
Plasmonic catalysis is emerging as a dynamic field in heterogeneous catalysis and holds great promise for the efficient utilization of solar energy.Central to the development of plasmonic catalysis is the design of ef...Plasmonic catalysis is emerging as a dynamic field in heterogeneous catalysis and holds great promise for the efficient utilization of solar energy.Central to the development of plasmonic catalysis is the design of efficient plasmonic nanocatalysts.In this report,plasmonic gap nanostructures(PGNs)on the basis of Au@poly(o-phenylenediamine)(POPD)@Pd sandwich nanostructures are synthesized as plasmonic nanocatalysts by an in-situ reduction synthetic strategy,which allows for the precise engineering of the POPD gap size between plasmonic Au and catalytic Pd components.The introduction of conducting POPD nanogap in PGNs not only effectively enhances their light harvesting capability,but also provides an effective charge transfer channel for harnessing the photogenerated hot charge carriers.In this respect,distinct gap-dependent performances in plasmon-enhanced electrocatalysis of ethanol oxidation reactions(EOR)are demonstrated with the PGN nanocatalysts and over 2.5 folds of enhancement can be achieved.A volcano plot is derived to describe the relationship between the catalytic activities and gap size of the PGN nanocatalysts,which is well explained by the interplay of their light harvesting and charge transport capabilities.These results highlight the importance of gap engineering in PGNs for plasmonic catalysis and offer the promise of developing efficient plasmonic nanocatalysts for other heterogeneous catalytic reactions.展开更多
AIM: To investigate the characteristics of the progression of islet β cell function in Chinese latent autoimmune diabetes in adult (LADA) patients with glutamic acid decarboxylase antibody (GAD-Ab) positivity, and to...AIM: To investigate the characteristics of the progression of islet β cell function in Chinese latent autoimmune diabetes in adult (LADA) patients with glutamic acid decarboxylase antibody (GAD-Ab) positivity, and to explore the prognostic factors for β cell function. METHODS: Forty-five LADA patients with GAD-Ab positivity screened from phenotypic type 2 diabetic (T2DM) patients and 45 T2DM patients without GAD-Ab matched as controls were followed-up every 6 mo. Sixteen patients in LADA1 and T2DM1 groups respectively have been followed-up for 6 years, while 29 patients in LADA2 and T2DM2 groups respectively for only 1.5 years. GAD-Ab was determined by radioligand assay, and C-peptides (CP) by radioimmune assay.RESULTS: The percentage of patients whose fasting CP(FCP) decreased more than 50% compared with thebaseline reached to 25.0% at 1.5th year in LADA1 group, and FCP level decreased (395.8±71.5 vs 572.8±72.3 pmol/L, P＜0.05) at 2.5th year and continuously went down to the end of follow-up. No significant changes of the above parameters were found in T2DM1 group. The average decreased percentages of FCP per year in LADA and T2DM patients were 15.8% (4.0-91.0%) and 5.2% (-3.5 to 35.5%, P= 0.000) respectively. The index of GAD-Ab was negatively correlated with the FCP in LADA patients (rs= -0.483, P = 0.000). The decreased percentage of FCP per year in LADA patients were correlated with GAD-Ab index, body mass index (BMI) and age at onset (rs = 0.408, -0.301 and -0.523 respectively, P＜0.05). Moreover, GAD-Ab wasthe only risk factor for predicting βcell failure in LADA patients (B = 1.455, EXP (B) = 4.283, P = 0.023). CONCLUSION: The decreasing rate of islet β cell function in LADA, being highly heterogeneous, is three times that of T2DM patients. The titer of GAD-Ab is an important predictor for the progression of islet β cell function, and age at onset and BMI could also act as the predictors.展开更多
Nonalcoholic fatty liver disease(NAFLD)is a prevalent medical condition with an ever-growing trend.Although multiple intracellular mechanisms are involved,endoplasmic reticulum(ER)stress has been demonstrated to play ...Nonalcoholic fatty liver disease(NAFLD)is a prevalent medical condition with an ever-growing trend.Although multiple intracellular mechanisms are involved,endoplasmic reticulum(ER)stress has been demonstrated to play a significant role in the genesis and progression.Most of the research supports the advantages of exercise for NAFLD.However,little is known about the molecular mechanism(s)that underpin the effectiveness of exercise training in NAFLD.This study aimed to identify how aerobic exercise affected hepatic ER stress in a mouse NAFLD model.In this study,the mice were fed either a standard diet(SD)or a high-fat diet(HFD)for 17 weeks.HFD mice were trained on a treadmill during the last eight weeks.All animals were tested for serum levels of biochemical assays,protein expression,and gene expression.The hematoxylin and eosin,Oil red O,and immunohistochemistry staining were also performed.The results indicated that a high-fat diet generated NAFLD,with serum lipid disruption and hepatic function impairment,and increased GRP78 and ATF6 expressions.However,aerobic training reversed the majority of these alterations.It is concluded that NAFLD appears to be associated with hepatic ER stress response,and aerobic exercise mitigates NAFLD via lowering ER stress proteins GRP78 and ATF6.展开更多
The various advantages of organic polymer monoliths, including relatively simple preparation processes,abundant monomer availability, and a wide application range of pH, have attracted the attention of chromatographer...The various advantages of organic polymer monoliths, including relatively simple preparation processes,abundant monomer availability, and a wide application range of pH, have attracted the attention of chromatographers. Organic polymer monoliths prepared by traditional methods only have macropores and mesopores, and micropores of less than 50 nm are not commonly available. These typical monoliths are suitable for the separation of biological macromolecules such as proteins and nucleic acids, but their ability to separate small molecular compounds is poor. In recent years, researchers have successfully modified polymer monoliths to achieve uniform compact pore structures. In particular, microporous materials with pores of 50 nm or less that can provide a large enough surface area are the key to the separation of small molecules. In this review, preparation methods of polymer monoliths for high-performance liquid chromatography, including ultra-high cross-linking technology, post-surface modification, and the addition of nanomaterials, are discussed. Modified monolithic columns have been used successfully to separate small molecules with obvious improvements in column efficiency.展开更多
Introduction:Oral fluids(OFs)have been broadly used as non-invasive samples for evaluating protective IgG antibodies from natural infection or vaccination,especially in pediatric populations.Methods:Paired OF and seru...Introduction:Oral fluids(OFs)have been broadly used as non-invasive samples for evaluating protective IgG antibodies from natural infection or vaccination,especially in pediatric populations.Methods:Paired OF and serum were collected from both individuals who received a booster dose of the inactive coronavirus disease 2019(COVID-19)vaccine as well as those who did not have a history of COVID-19 vaccination and infection(as the control group).The total human IgG antibody(HIgG)content was evaluated as a marker of OF sampling quality.An in-house adapted magnetic particle-based chemiluminescence immunoassay was used for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)IgG antibody detection in the OF.The SARS-CoV-2 IgG antibody in the serum samples was detected using a commercial immunoassay.Results:In total,579 paired OF and serum samples were collected.An additional 172 OF samples were collected from preschool children.The results indicated that the HIgG concentration in qualified OF samples should be higher than 0.3μg/mL.Compared to the serum assay,the in-house OF immunoassay for detecting IgG antibodies against SARS-CoV-2 had 95.06%accuracy,95.03%sensitivity,and 100%specificity.Conclusions:Overall,the in-house immunoassay for detecting SARS-CoV-2 IgG antibodies in OF showed high potential for application towards serological surveillance and immunization effect assessment after large-scale,inactive COVID-19 vaccination in China.展开更多
Seeds establish dormancy to delay germination until the arrival of a favorable growing season.In this study,we identify a fate switch comprised of the MKK3–MPK7 kinase cascade and the ethylene response factor ERF4 th...Seeds establish dormancy to delay germination until the arrival of a favorable growing season.In this study,we identify a fate switch comprised of the MKK3–MPK7 kinase cascade and the ethylene response factor ERF4 that is responsible for the seed state transition from dormancy to germination.We show that dormancy-breaking factors activate the MKK3–MPK7 module,which affects the expression of some a-EXPANSIN(EXPA)genes to control seed dormancy.Furthermore,we identify a direct downstream substrate of this module,ERF4,which suppresses the expression of these EXPAs by directly binding to the GCC boxes in their exon regions.The activated MKK3–MPK7 module phosphorylates ERF4,leading to its rapid degradation and thereby releasing its inhibitory effect on the expression of these EXPAs.Collectively,our work identifies a signaling chain consisting of protein phosphorylation,degradation,and gene transcription,by which the germination promoters within the embryo sense and are activated by germination signals from ambient conditions.展开更多
Developing efficient and stable electrocatalyst to hydrogen evolution reaction adaptable for electrolytes with different p H is a big challenge.In this work,a hierarchically structured ternary nanohybrid composed of f...Developing efficient and stable electrocatalyst to hydrogen evolution reaction adaptable for electrolytes with different p H is a big challenge.In this work,a hierarchically structured ternary nanohybrid composed of flower-like Ru nanoparticles,rigid macrocyclic cucurbit[6]uril(CB[6])and carboxylated multiwalled carbon nanotubes(MWCNTs)was successfully prepared by chemical wet method.Benefited by the structural merits of flower-like Ru nanoparticles exposed abundant active sites supported by the MWCNTs holding superior mass transport and electrons transfer ability as well as the existence of CB[6],the obtained catalyst exhibited outstanding HER activities with overpotentials of 27,37 and 70 m V at-10 m A/cm^(2) in alkaline,acidic,and neutral electrolytes,respectively.Under the same electrocatalytic operation conditions,the HER performance is comparable or superior to commercial Pt/C catalyst(47,27and 49 m V).Besides,chronopotentiometric and accelerated stability test also revealed its extraordinary stability,which could be further employed for electrocatalytic procedure in a broad pH range.展开更多
The unique hierarchical nitrogen-doped carbon nanocages(h NCNC) are used as a new support to homogeneously immobilize spinel Co Fe_2O_4 nanoparticles by a facile solvothermal method. The so-constructed hierarchical Co...The unique hierarchical nitrogen-doped carbon nanocages(h NCNC) are used as a new support to homogeneously immobilize spinel Co Fe_2O_4 nanoparticles by a facile solvothermal method. The so-constructed hierarchical Co Fe_2O_4/h NCNC catalyst exhibits a high oxygen reduction activity with an onset potential of0.966 V and half-wave potential of 0.819 V versus reversible hydrogen electrode, far superior to the corresponding 0.846 and 0.742 V for its counterpart of Co Fe_2O_4/h CNC with undoped hierarchical carbon nanocages(h CNC) as the support, which locates at the top level for spinel-based catalysts to date.Consequently, the Co Fe_2O_4/h NCNC displays the superior performance to the Co Fe_2O_4/h CNC, when used as the cathode catalysts in the home-made Al-air batteries. X-ray photoelectron spectroscopy characterizations reveal the more charge transfer from Co Fe_2O_4 to h NCNC than to h CNC, indicating the stronger interaction between Co Fe_2O_4 and h NCNC due to the nitrogen participation. The enhanced interaction and hierarchical morphology favor the high dispersion and modification of electronic states for the active species as well as the mass transport during the oxygen reduction process, which plays a significant role in boosting the electrocatalytic performances. In addition, we noticed the high sensitivity of O 1 s spectrum to the particle size and chemical environment for spinel oxides, which is used as an indicator to understand the evolution of ORR activities for all the Co Fe_2O_4-related contrast catalysts. Accordingly,the well-defined structure-performance relationship is demonstrated by the combination of experimental characterizations with theoretical calculations. This study provides a promising strategy to develop efficient, inexpensive and durable oxygen reduction electrocatalysts by tuning the interaction between spinel metal oxides and the carbon-based supports.展开更多
Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes,which could bring a new revolution for information technology.However,the rational design of such molecules remains ...Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes,which could bring a new revolution for information technology.However,the rational design of such molecules remains challenging.Here two rigid adamantanol ligand based dysprosium(III)complexes([Dy(1-AdO)_(2)(py)_(5)]BPh_(4)-1 and[Dy(2-AdO)_(2)(py)_(5)]BPh_(4)-2)with pentagonal-bipyramidal coordination geometry and local D5h symmetry were successfully prepared,which display excellent single-molecule magnet(SMM)behavior(U_(eff)≈1835 K,T_(B)_(ZFC)≈24 K,T_(B)^(100s)≈17 K and T_(B)^(H)=23 K for 1;U_(eff)≈1756 K,T_(B)^(ZFC)≈20 K,T_(B)^(100s)≈16 K and T_(B)^(H)=23 K for 2)due to the much weakened vibration in low energy regimes.Remarkably,the large energy barriers and high blocking temperatures for these two complexes in solid states are well preserved in solution.This is never observed in previous studies of SMMs,indicating that the adamantanol is rigid and can be introduced to make the composed molecules stable enough to maintain the solid state magnetic property in solution.展开更多
As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in thi...As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments.展开更多
基金Supported by the National Natural Science Foundation of China,No.30370315,No.30171044 and Medical and pharmaceutical Research Fund of PLA,No.01MA185
文摘AIM: To investigate the expression of NDRG2 and mutation of the entire coding region of NDRG2 in human liver and pancreatic cancers, and to further discuss the possible causes of NDRG2 distinct expression patterns.METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze the expression of NDRG2 mRNA in 37 fresh cancer specimens (including 8 cases of pancreatic cancer and 29 cases of liver cancer) and adjacent normal tissues collected from clinical operation. In addition,mutation analysis of the whole coding region of NDRG2 in these cancers was examined by polymerase chain reactionsingle strand conformational polymorphism (PCR-SSCP).RESULTS: Compared with adjacent normal tissues, the expression levels of NDRG2 mRNA in corresponding cancer tissues reduced significantly (pancreatic cancer: 0.680±0.112 vs 2.089±0.214, P<0.01) (liver cancer: 0.894±0.098 vs 1.345±0.177, P<0.05). Using PCR-SSCP, the mutation of the whole coding region of NDRG2 was not found in those cancer tissues where the expression of NDRG2 mRNA reduced markedly.CONCLUSION: NDRG2 gene might express differently between normal tissues and cancer tissues, and might play an important role in the development of pancreatic cancer and liver cancer. Low expression of NDRG2 might be unrelated to the mutation of coding region of NDRG2.
基金Supported by The Chinese Medicine Technology Item of Peking City (No.JJ2005-10)Beijing Municipal Commission of Education (No. M200610025003)
文摘To study the inhibitory effect of Huqi San （Qi- protecting powder） on rat prehepatocarcinoma induced by diethylinitrosamine （DEN） by analyzing the mutational activation of c-fos proto-oncogene and over-expression of c-jun and c-myc oncogenes. METHODS： A Solt-Farber two-step test model of prehepatocarcinoma was induced in rats by DEN and 2-acetylaminofluorene （AAF） to investigate the modifying effects of Huqi San on the expression of c-jun, c-fos and c-myc in DEN-mediated hepatocarcinogenesis. Huqi San was made of eight medicinal herbs containing glycoprival granules, in which each milliliter contains 0.38 g crude drugs. T-glutamy-transpeptidase-isoenzyme （T-GTase） was determined with histochemical methods. Level of 8-hydroxydeoxyguanosine （OHdG） formed in liver and c-jun, c-fos and c-myc proto-oncogenes were detected by immunohistochemical methods. RESULTS： The level of 8-OHdG, a mark of oxidative DNA damage, was significantly decreased in the liver of rats with prehepatocarcinoma induced by DEN who received 8 g/kg body weight or 4 g/kg body weight Huqi San before （1 wk） and after DEN exposure （4 wk）. Huqi San- treated rats showed a significant decrease in number of T-GT positive foci （P 〈 0.001, prevention group： 4.96-0.72 vs 29.46-2.17; large dose therapeutic group： 7.53-0.88 vs 29.46-2.17）. On the other hand, significant changes in expression of c-jun, c-fos and c-myc were found in Huqi San-treated rats. CONCLUSION： Activation of c-jun, c-fos and c-myc plays a crucial role in the pathogenesis of liver cancer.Huqi San can inhibit the over-expression of c-jun, c-fos and c-myc oncogenes and liver preneolastic lesions induced by DEN.
文摘Dear Editor,RNA knockdown in vivo carries significant potential for dis-ease modeling and therapies.Despite the emerging approaches of CRISPR/Cas9-mediated permanent knock out of targeted genes,strategies targeting RNA for disruption are advantageous in the treatment of acquired metabolic disorders when permanent modification of genome DNA is not appropriate,and RNA virus infection diseases when pathogenic DNA is not available(such as SARS-Cov-2 and MERS infections).
基金supported by the National Natural Science Foundation of China (32001612)the Science, Technology and Innovation Commission of Shenzhen Municipality (JCYJ20180306173702268 and KCXFZ20201221173203009)+2 种基金Key-Area Research and Development Program of Guangdong Province (2021B0707010006)Dapeng New District Science and Technology Program (KJYF202101-09 and RCTD20180102)Guangdong Basic and Applied Basic Research Foundation (2019A1515110966)
文摘Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)remains unclear.Here,we performed a genome-wide association study and linkage mapping to dissect the genetic basis of seed dormancy in rice.Our findings suggest that Seed Dormancy4(Sdr4),a central modulator of seed dormancy,integrates the abscisic acid and gibberellic acid signaling pathways at the transcriptional level.Haplotype analysis revealed that three Sdr4 alleles in rice cultivars already existed in ancestral Oryza rufipogon accessions.Furthermore,like the semi-dwarf 1(SD1)and Rc loci,Sdr4 underwent selection during the domestication and improvement of Asian cultivated rice.The distribution frequency of the Sdr4-n allele in different locations in Asia is negatively associated with local annual temperature and precipitation.Finally,we developed functional molecular markers for Sdr4,SD1,and Rc for use in molecular breeding.Our results provide clues about the molecular basis of Sdr4-regulated seed dormancy.Moreover,these findings provide guidance for utilizing the favorable alleles of Sdr4 and Rc to synergistically boost PHS resistance,yield,and quality in modern rice varieties.
基金This publication was financially supported by the National Key R&D Program of China(2018YFD0400202 and 2018YFD0400200).
文摘A high performance liquid chromatography-ultraviolet(HPLC-UV)fingerprint method for the overall chemical analysis of edible mushrooms was established based on Auricularia heimuer for the first time,and then applied to analyze 60 batches of A.heimuer,Auricularia cornea.Auricularia cornea*Yu Muer’and TremeUa fuciformis.A total of 9 characteristic peaks of A.heimuer.11 characteristic peaks of A.cornea,6 characteristic peaks of A.cornea‘Yu Muer’,and 9 characteristic peaks of I fuciformis were designated.Then,a combinatory analysis,including similarity evaluation,hierarchical cluster analysis and principal component analysis,revealed the chemical consistency and difference between samples from the same and different species.The HPLC fingerprint method established in this paper could be used to characterize the components of A.heimuer,A.cornea,A.cornea‘Yu Muer’,and T.fuciformis and discriminate the 4 edible mushrooms effectively in combination with pattern recognition analysis.
基金supported by the National Natural Science Foundation of China(No.82003298)the Scientiffc and Technological Project of Henan Province(No.232102310392)+5 种基金the Key Research and Development Projects of Henan Province(No.222102310453,212102311025)Postdoctoral Research Grant in Henan Province(No.201901025)the Key Research Project of Henan Higher Education Institutions(No.18A350003)Open Fund of Key Laboratory of Targeting Therapy and Diagnosis for Critical Diseases,Henan Province(No.NMZL2020102)the Natural Science Foundation of Chongqing(No.cstc2019jcyj-msxmX0035)the Scientiffc Research Seedling Project of Chongqing Medicinal Biotechnology Association(No.cmba2022kyym-zkxmQ0009).
文摘Postoperative tumor recurrence remains a predominant cause of treatment failure. In this study, we developed an in situ injectable hydrogel, termed MPB-NO@DOX + ATRA gel, which was locally formed within the tumor resection cavity. The MPB-NO@DOX + ATRA gel was fabricated by mixing a thrombin solution, a fibrinogen solution containing all-trans retinoic acid (ATRA), and a Mn/NO-based immune nano-activator termed MPB-NO@DOX. ATRA promoted the differentiation of cancer stem cells, inhibited cancer cell migration, and affected the polarization of tumor-associated macrophages. The outer MnO2 shell disintegrated due to its reaction with glutathione and hydrogen peroxide in the cytoplasm to release Mn2+ and produce O2, resulting in the release of doxorubicin (DOX). The released DOX entered the nucleus and destroyed DNA, and the fragmented DNA cooperated with Mn2+ to activate the cGAS-STING pathway and stimulate an anti-tumor immune response. In addition, when MPB-NO@DOX was exposed to 808 nm laser irradiation, the Fe-NO bond was broken to release NO, which downregulated the expression of PD-L1 on the surface of tumor cells and reversed the immunosuppressive tumor microenvironment. In conclusion, the MPB-NO@DOX + ATRA gel exhibited excellent anti-tumor efficacy. The results of this study demonstrated the great potential of in situ injectable hydrogels in preventing postoperative tumor recurrence.
基金National Natural Science Foundation of China,Grant/Award Numbers:62276285,62236011Major Project of National Social Sciences Foundation of China,Grant/Award Number:20&ZD279。
文摘Mahjong,a complex game with hidden information and sparse rewards,poses significant challenges.Existing Mahjong AIs require substantial hardware resources and extensive datasets to enhance AI capabilities.The authors propose a transformer‐based Mahjong AI(Tjong)via hierarchical decision‐making.By utilising self‐attention mechanisms,Tjong effectively captures tile patterns and game dynamics,and it decouples the decision pro-cess into two distinct stages:action decision and tile decision.This design reduces de-cision complexity considerably.Additionally,a fan backward technique is proposed to address the sparse rewards by allocating reversed rewards for actions based on winning hands.Tjong consists of 15M parameters and is trained using approximately 0.5 M data over 7 days of supervised learning on a single server with 2 GPUs.The action decision achieved an accuracy of 94.63%,while the claim decision attained 98.55%and the discard decision reached 81.51%.In a tournament format,Tjong outperformed AIs(CNN,MLP,RNN,ResNet,VIT),achieving scores up to 230%higher than its opponents.Further-more,after 3 days of reinforcement learning training,it ranked within the top 1%on the leaderboard on the Botzone platform.
基金the National Natural Science Foundation of China(Nos.62276285 and 62236011)the Major Projects of Social Science Fundation of China(No.20&ZD279)。
文摘The game of Tibetan Go faces the scarcity of expert knowledge and research literature.Therefore,we study the zero learning model of Tibetan Go under limited computing power resources and propose a novel scaleinvariant U-Net style two-headed output lightweight network TibetanGoTinyNet.The lightweight convolutional neural networks and capsule structure are applied to the encoder and decoder of TibetanGoTinyNet to reduce computational burden and achieve better feature extraction results.Several autonomous self-attention mechanisms are integrated into TibetanGoTinyNet to capture the Tibetan Go board’s spatial and global information and select important channels.The training data are generated entirely from self-play games.TibetanGoTinyNet achieves 62%–78%winning rate against other four U-Net style models including Res-UNet,Res-UNet Attention,Ghost-UNet,and Ghost Capsule-UNet.It also achieves 75%winning rate in the ablation experiments on the attention mechanism with embedded positional information.The model saves about 33%of the training time with 45%–50%winning rate for different Monte–Carlo tree search(MCTS)simulation counts when migrated from 9×9 to 11×11 boards.Code for our model is available at https://github.com/paulzyy/TibetanGoTinyNet.
基金supported by the National Natural Science Foundation of China(Nos.61725305,U1909206,T2121002,and62073196)the Postdoctoral Innovative Talent Support Program(No.BX2021010)the S&T Program of Hebei Province,China(No.F2020203037)。
文摘To tackle the problem of aquatic environment pollution,a vision-based autonomous underwater garbage cleaning robot has been developed in our laboratory.We propose a garbage detection method based on a modified YOLOv4,allowing high-speed and high-precision object detection.Specifically,the YOLOv4 algorithm is chosen as a basic neural network framework to perform object detection.With the purpose of further improvement on the detection accuracy,YOLOv4 is transformed into a four-scale detection method.To improve the detection speed,model pruning is applied to the new model.By virtue of the improved detection methods,the robot can collect garbage autonomously.The detection speed is up to 66.67 frames/s with a mean average precision(mAP)of 95.099%,and experimental results demonstrate that both the detection speed and the accuracy of the improved YOLOv4 are excellent.
基金his work was supported by the National Natural Science Foundation of China(Nos.21974131,22072144,and 22102171)the Department of Science and Technology of Jilin Province(No.20200201080JC)the Natural Science Foundation of Jilin Province(No.YDZJ202201ZYTS341).
文摘Plasmonic catalysis is emerging as a dynamic field in heterogeneous catalysis and holds great promise for the efficient utilization of solar energy.Central to the development of plasmonic catalysis is the design of efficient plasmonic nanocatalysts.In this report,plasmonic gap nanostructures(PGNs)on the basis of Au@poly(o-phenylenediamine)(POPD)@Pd sandwich nanostructures are synthesized as plasmonic nanocatalysts by an in-situ reduction synthetic strategy,which allows for the precise engineering of the POPD gap size between plasmonic Au and catalytic Pd components.The introduction of conducting POPD nanogap in PGNs not only effectively enhances their light harvesting capability,but also provides an effective charge transfer channel for harnessing the photogenerated hot charge carriers.In this respect,distinct gap-dependent performances in plasmon-enhanced electrocatalysis of ethanol oxidation reactions(EOR)are demonstrated with the PGN nanocatalysts and over 2.5 folds of enhancement can be achieved.A volcano plot is derived to describe the relationship between the catalytic activities and gap size of the PGN nanocatalysts,which is well explained by the interplay of their light harvesting and charge transport capabilities.These results highlight the importance of gap engineering in PGNs for plasmonic catalysis and offer the promise of developing efficient plasmonic nanocatalysts for other heterogeneous catalytic reactions.
基金Supported by the National Natural Science Foundation of China,No. 39370343 the National Ministry of Health Youth Talents Foundation, No. Q9420 the Hunan Health Bureau Key Scientific Funds, No. 9736, 2001-Z04
文摘AIM: To investigate the characteristics of the progression of islet β cell function in Chinese latent autoimmune diabetes in adult (LADA) patients with glutamic acid decarboxylase antibody (GAD-Ab) positivity, and to explore the prognostic factors for β cell function. METHODS: Forty-five LADA patients with GAD-Ab positivity screened from phenotypic type 2 diabetic (T2DM) patients and 45 T2DM patients without GAD-Ab matched as controls were followed-up every 6 mo. Sixteen patients in LADA1 and T2DM1 groups respectively have been followed-up for 6 years, while 29 patients in LADA2 and T2DM2 groups respectively for only 1.5 years. GAD-Ab was determined by radioligand assay, and C-peptides (CP) by radioimmune assay.RESULTS: The percentage of patients whose fasting CP(FCP) decreased more than 50% compared with thebaseline reached to 25.0% at 1.5th year in LADA1 group, and FCP level decreased (395.8±71.5 vs 572.8±72.3 pmol/L, P＜0.05) at 2.5th year and continuously went down to the end of follow-up. No significant changes of the above parameters were found in T2DM1 group. The average decreased percentages of FCP per year in LADA and T2DM patients were 15.8% (4.0-91.0%) and 5.2% (-3.5 to 35.5%, P= 0.000) respectively. The index of GAD-Ab was negatively correlated with the FCP in LADA patients (rs= -0.483, P = 0.000). The decreased percentage of FCP per year in LADA patients were correlated with GAD-Ab index, body mass index (BMI) and age at onset (rs = 0.408, -0.301 and -0.523 respectively, P＜0.05). Moreover, GAD-Ab wasthe only risk factor for predicting βcell failure in LADA patients (B = 1.455, EXP (B) = 4.283, P = 0.023). CONCLUSION: The decreasing rate of islet β cell function in LADA, being highly heterogeneous, is three times that of T2DM patients. The titer of GAD-Ab is an important predictor for the progression of islet β cell function, and age at onset and BMI could also act as the predictors.
基金This work was provided by the National Natural Science Foundation of China(No.31900846)the Science and Technology Program of Sichuan,China(No.2020YFS0436).We would like to thank Jiaqian Wang,Yalong Li and Changjun Jiang who assisted in performing daily training of the mice over the course of the study.
文摘Nonalcoholic fatty liver disease(NAFLD)is a prevalent medical condition with an ever-growing trend.Although multiple intracellular mechanisms are involved,endoplasmic reticulum(ER)stress has been demonstrated to play a significant role in the genesis and progression.Most of the research supports the advantages of exercise for NAFLD.However,little is known about the molecular mechanism(s)that underpin the effectiveness of exercise training in NAFLD.This study aimed to identify how aerobic exercise affected hepatic ER stress in a mouse NAFLD model.In this study,the mice were fed either a standard diet(SD)or a high-fat diet(HFD)for 17 weeks.HFD mice were trained on a treadmill during the last eight weeks.All animals were tested for serum levels of biochemical assays,protein expression,and gene expression.The hematoxylin and eosin,Oil red O,and immunohistochemistry staining were also performed.The results indicated that a high-fat diet generated NAFLD,with serum lipid disruption and hepatic function impairment,and increased GRP78 and ATF6 expressions.However,aerobic training reversed the majority of these alterations.It is concluded that NAFLD appears to be associated with hepatic ER stress response,and aerobic exercise mitigates NAFLD via lowering ER stress proteins GRP78 and ATF6.
文摘The various advantages of organic polymer monoliths, including relatively simple preparation processes,abundant monomer availability, and a wide application range of pH, have attracted the attention of chromatographers. Organic polymer monoliths prepared by traditional methods only have macropores and mesopores, and micropores of less than 50 nm are not commonly available. These typical monoliths are suitable for the separation of biological macromolecules such as proteins and nucleic acids, but their ability to separate small molecular compounds is poor. In recent years, researchers have successfully modified polymer monoliths to achieve uniform compact pore structures. In particular, microporous materials with pores of 50 nm or less that can provide a large enough surface area are the key to the separation of small molecules. In this review, preparation methods of polymer monoliths for high-performance liquid chromatography, including ultra-high cross-linking technology, post-surface modification, and the addition of nanomaterials, are discussed. Modified monolithic columns have been used successfully to separate small molecules with obvious improvements in column efficiency.
基金Supported by the Capital’s Funds for Health Improvement and Research(2021-1G-3011).
文摘Introduction:Oral fluids(OFs)have been broadly used as non-invasive samples for evaluating protective IgG antibodies from natural infection or vaccination,especially in pediatric populations.Methods:Paired OF and serum were collected from both individuals who received a booster dose of the inactive coronavirus disease 2019(COVID-19)vaccine as well as those who did not have a history of COVID-19 vaccination and infection(as the control group).The total human IgG antibody(HIgG)content was evaluated as a marker of OF sampling quality.An in-house adapted magnetic particle-based chemiluminescence immunoassay was used for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)IgG antibody detection in the OF.The SARS-CoV-2 IgG antibody in the serum samples was detected using a commercial immunoassay.Results:In total,579 paired OF and serum samples were collected.An additional 172 OF samples were collected from preschool children.The results indicated that the HIgG concentration in qualified OF samples should be higher than 0.3μg/mL.Compared to the serum assay,the in-house OF immunoassay for detecting IgG antibodies against SARS-CoV-2 had 95.06%accuracy,95.03%sensitivity,and 100%specificity.Conclusions:Overall,the in-house immunoassay for detecting SARS-CoV-2 IgG antibodies in OF showed high potential for application towards serological surveillance and immunization effect assessment after large-scale,inactive COVID-19 vaccination in China.
基金supported by the National Natural Science Foundation of China(grant nos.32000250 and 32170364)the China Postdoctoral Science Foundation(grant no.2020M682997)+2 种基金the Key Area Research and Development Program of Guangdong Province(grant no.2021B0707010006)the Science,Technology and Innovation Commission of Shenzhen Municipality(grant nos.KCXFZ-20201221173203009 and KCXFZ20211020164207012)the Dapeng New District Science and Technology Program(grant nos.KJYF202101-09 and RCTD20180102)。
文摘Seeds establish dormancy to delay germination until the arrival of a favorable growing season.In this study,we identify a fate switch comprised of the MKK3–MPK7 kinase cascade and the ethylene response factor ERF4 that is responsible for the seed state transition from dormancy to germination.We show that dormancy-breaking factors activate the MKK3–MPK7 module,which affects the expression of some a-EXPANSIN(EXPA)genes to control seed dormancy.Furthermore,we identify a direct downstream substrate of this module,ERF4,which suppresses the expression of these EXPAs by directly binding to the GCC boxes in their exon regions.The activated MKK3–MPK7 module phosphorylates ERF4,leading to its rapid degradation and thereby releasing its inhibitory effect on the expression of these EXPAs.Collectively,our work identifies a signaling chain consisting of protein phosphorylation,degradation,and gene transcription,by which the germination promoters within the embryo sense and are activated by germination signals from ambient conditions.
基金the financial support from the National Key R&D Program of China(Nos.2017YFA0206802,2018YFA0704502)the National Natural Science Foundation of China(NSFC,No.22033008)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZZ103)。
文摘Developing efficient and stable electrocatalyst to hydrogen evolution reaction adaptable for electrolytes with different p H is a big challenge.In this work,a hierarchically structured ternary nanohybrid composed of flower-like Ru nanoparticles,rigid macrocyclic cucurbit[6]uril(CB[6])and carboxylated multiwalled carbon nanotubes(MWCNTs)was successfully prepared by chemical wet method.Benefited by the structural merits of flower-like Ru nanoparticles exposed abundant active sites supported by the MWCNTs holding superior mass transport and electrons transfer ability as well as the existence of CB[6],the obtained catalyst exhibited outstanding HER activities with overpotentials of 27,37 and 70 m V at-10 m A/cm^(2) in alkaline,acidic,and neutral electrolytes,respectively.Under the same electrocatalytic operation conditions,the HER performance is comparable or superior to commercial Pt/C catalyst(47,27and 49 m V).Besides,chronopotentiometric and accelerated stability test also revealed its extraordinary stability,which could be further employed for electrocatalytic procedure in a broad pH range.
基金supported by the National Natural Science Foundation of China (21473089, 51232003, 21373108, 21573107, and 51571110)the National Basic Research Program of China (2013CB932902)+2 种基金Changzhou Technology Support Program (CE20130032)Priority Academic Program Development of Jiangsu Higher Education InstitutionsFundamental Research Funds for the Central Universities
文摘The unique hierarchical nitrogen-doped carbon nanocages(h NCNC) are used as a new support to homogeneously immobilize spinel Co Fe_2O_4 nanoparticles by a facile solvothermal method. The so-constructed hierarchical Co Fe_2O_4/h NCNC catalyst exhibits a high oxygen reduction activity with an onset potential of0.966 V and half-wave potential of 0.819 V versus reversible hydrogen electrode, far superior to the corresponding 0.846 and 0.742 V for its counterpart of Co Fe_2O_4/h CNC with undoped hierarchical carbon nanocages(h CNC) as the support, which locates at the top level for spinel-based catalysts to date.Consequently, the Co Fe_2O_4/h NCNC displays the superior performance to the Co Fe_2O_4/h CNC, when used as the cathode catalysts in the home-made Al-air batteries. X-ray photoelectron spectroscopy characterizations reveal the more charge transfer from Co Fe_2O_4 to h NCNC than to h CNC, indicating the stronger interaction between Co Fe_2O_4 and h NCNC due to the nitrogen participation. The enhanced interaction and hierarchical morphology favor the high dispersion and modification of electronic states for the active species as well as the mass transport during the oxygen reduction process, which plays a significant role in boosting the electrocatalytic performances. In addition, we noticed the high sensitivity of O 1 s spectrum to the particle size and chemical environment for spinel oxides, which is used as an indicator to understand the evolution of ORR activities for all the Co Fe_2O_4-related contrast catalysts. Accordingly,the well-defined structure-performance relationship is demonstrated by the combination of experimental characterizations with theoretical calculations. This study provides a promising strategy to develop efficient, inexpensive and durable oxygen reduction electrocatalysts by tuning the interaction between spinel metal oxides and the carbon-based supports.
基金This work was supported by the National Natural Science Foundation of China(Nos.21773130,21871219 and 21971203)the Key Laboratory Construction Program of Xi'an Municipal Bu-reau of Science and Technology(No.201805056ZD7CG40)+1 种基金the Key Scientific and Technological Innovation Team of Shaanxi Province(No.2020TD-001)the Fundamental Research Funds for Central Universities。
文摘Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes,which could bring a new revolution for information technology.However,the rational design of such molecules remains challenging.Here two rigid adamantanol ligand based dysprosium(III)complexes([Dy(1-AdO)_(2)(py)_(5)]BPh_(4)-1 and[Dy(2-AdO)_(2)(py)_(5)]BPh_(4)-2)with pentagonal-bipyramidal coordination geometry and local D5h symmetry were successfully prepared,which display excellent single-molecule magnet(SMM)behavior(U_(eff)≈1835 K,T_(B)_(ZFC)≈24 K,T_(B)^(100s)≈17 K and T_(B)^(H)=23 K for 1;U_(eff)≈1756 K,T_(B)^(ZFC)≈20 K,T_(B)^(100s)≈16 K and T_(B)^(H)=23 K for 2)due to the much weakened vibration in low energy regimes.Remarkably,the large energy barriers and high blocking temperatures for these two complexes in solid states are well preserved in solution.This is never observed in previous studies of SMMs,indicating that the adamantanol is rigid and can be introduced to make the composed molecules stable enough to maintain the solid state magnetic property in solution.
基金the support of Key Laboratory of Chinese Medicine Preparation of Solid Dispersion,Gansu Longshenrongfa Pharmaceutical Industry Co.,Ltd.,Gansu Province,China
文摘As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments.
