A new method based on the combining of the wavelet theory with the fractal theory and named wavelet fractal peak position method (WFPPM) is introduced to ex-tract the number of the components and the relevant peak pos...A new method based on the combining of the wavelet theory with the fractal theory and named wavelet fractal peak position method (WFPPM) is introduced to ex-tract the number of the components and the relevant peak positions from overlapping signals in chemistry. The over-lapping signal is first transformed into continuous wavelet transform value of time domain in certain dilation range via continuous wavelet transform (CWT), and then changed into capacity dimensions (Dc). The number of the components and the relevant positions of overlapping peaks can be iden-tified easily according to the change of Dc. An investigation concerning the influence of different dilation ranges on the peak positions extracted by WFPPM is also provided. Stud-ies show that the WFPPM is an efficient tool for extracting the peak positions and identifying the number of peaks from unresolved signals, even when this kind of overlapping is significantly serious. Relative errors of less than 1.0% in peak positions are found when WFPPM is used in the pro- cessing of the cadmium(Ⅱ)-indium(Ⅲ) mixture system. The analytical results demonstrate that the desired peak positions can be extracted conveniently, accurately and rapidly from an unresolved signal via WFPPM. Tremendous developing and applications based on currently reported WFPPM in extracting overlapping signals would be expected in the near future.展开更多
Site-specific pseudouridylations of rRNAs and snRNAs are directed by small guide RNAs that usually pos-sess conserved H and ACA motifs and the consensus secon-dary structure consisting of hairpin-hinge-hairpin-tail. I...Site-specific pseudouridylations of rRNAs and snRNAs are directed by small guide RNAs that usually pos-sess conserved H and ACA motifs and the consensus secon-dary structure consisting of hairpin-hinge-hairpin-tail. In this study, through screening cDNA library, three novel box H/ACA snoRNAs, termed SP12, SP16 and SP20, have been identified from fisson yeast Schizosacchromyces pombe. Each of the small RNAs possesses an ACA-like motif and exhibits secondary structures containing two or three large hairpin- like domains. Although the box H is noncanonical, SP20 can be potentially folded into a typical box H/ACA snoRNA-like structure and is predicted to guide two pseudouridylations, U1208 and U1053, on 18S rRNA. In contrast, SP12 and SP16 display different structures from SP20 and have no antisense elements to rRNAs or snRNAs. Obviously, they are new members of orphan guide snoRNAs whose functions remain elusive. The genes encoded for SP12 and SP16 are both lo-cated in long intergenic regions between protein-coding genes. A post-transcriptional processing for SP16 precursor was demonstrated. Interestingly, SP20 gene is nested inside a very hypothetical ORF, but transcribed in a reverse sense. Northern and RT-PCR analyses could not detect the tran-script from the hypothetical ORF, and therefore exclude the expression of the spurious gene. This is the first example that a genetic locus predicted for protein-coding gene actually encodes a small non-messenger RNA in S. pombe.展开更多
The results of sedimentary characteristics, grain-size, clay mineral, C/N and pollen analysis reveal the evolution history of the Shuangchi Maar Lake of Hainan Island as well as the short-term climate variations in tr...The results of sedimentary characteristics, grain-size, clay mineral, C/N and pollen analysis reveal the evolution history of the Shuangchi Maar Lake of Hainan Island as well as the short-term climate variations in tropical areas. It is testified that the Maar sediment system was sensitive in recording the rapid climate changes in the Holocene. These multidisciplinary results demonstrate that the thermal maximum in the Holocene climate lasted from 7200 to 2700 aBP, with several abrupt ephemeral vibrations occurring between 7250-6120 aBP and at around 4460, 3850 and 2700 aBP. In the late Holocene, particularly at ~2700 aBP, a distinct environmental change indicating an important climate transition in the tropical eastern Asia was recorded, probably responding to the enhancement of ENSO phenomena in the Pacific Ocean. In addition, the high-resolution algae record clearly indicates periodical climate fluctuations at 500 a cyclicity during the last 2500 years.展开更多
Danxia Landform belongs to red terrestrial clastic rock landform, which is characterized by its red cliffed scarp. The development of Danxia Landform research in China experienced three historic stages, i.e. initial e...Danxia Landform belongs to red terrestrial clastic rock landform, which is characterized by its red cliffed scarp. The development of Danxia Landform research in China experienced three historic stages, i.e. initial establishment, taking shape and expanding since the concept 'Danxia Landform' raised by Prof. Chen Guoda in 1939. As a new branch of geomorphology, Danxia geomorphology research is now stepping its ripe stage. In the 1990s, the search enters into an unprecedented grand occasion at the prompting of tourism exploit.展开更多
By constructing and screening the Schizosac-charomyces pombe nuclear cDNA library, a novel small nu-cleolar RNAs (snoRNA) was identified. The novel snoRNAdisplays structural features typical of C/D box snoRNA fam-ily ...By constructing and screening the Schizosac-charomyces pombe nuclear cDNA library, a novel small nu-cleolar RNAs (snoRNA) was identified. The novel snoRNAdisplays structural features typical of C/D box snoRNA fam-ily and possesses a 10-nt-long rRNA antisense element whichis predicted to guide the 2’-O-methylation of the fission yeast 25S rRNA at G940. As expected, the rRNA ribose-methyla-tion site predicted by the novel snoRNA was preciselymapped by a deoxynucleoside triphosphate concentration-dependent primer extension assay. The comparison of func-tional element of guide snoRNAs among eukaryotes reveals that the novel snoRNA is a partial counterpart of the bud-ding yeast snR60 and was termed snR60-II. snR60-II genenested in the intron of a non-coding RNA gene with an un-known function, which is the first example of a yeastsnoRNA encoded in an intron of a non-coding RNA gene.Furthermore, a number of yeast snR60 homologues were also identified from other fungi and fly. Our results reveal thatsnR60 exhibits diverse genomic organization in eukaryotes, implying the high mobility of snR60 gene in the course ofevolution.展开更多
The risk of drinking water is greatly concerned because of the large amount of pesticide applied to paddy field and the contamination of drinking water sources due to the runoff. A mathematical model is developed, ba...The risk of drinking water is greatly concerned because of the large amount of pesticide applied to paddy field and the contamination of drinking water sources due to the runoff. A mathematical model is developed, based on the mass balance, to predict the fate of paddy field pesticides from application, runoff and mixing in a river, taking account of the physical chemical properties and processes of volatilization, degradation, adsorption and desorption. The model is applied to a river basin in Japan to estimate the contaminant level of several popularly used pesticides at the water intakes. The health risk in drinking water induced by each pesticide concerned is estimated and evaluated by comparing with the acceptable daily intake values(ADI) and with that induced by trihalomethanes. An index to evaluate the total risk of all pesticides appearing in water is proposed. The methods for risk management are also discussed.展开更多
The authors investigate a kind of degenerate quadratic Hamiltonian systems with saddle-loop. Under quadratic perturbations, it is proved that the perturbed system has at most two limit cycles in the finite plane. The ...The authors investigate a kind of degenerate quadratic Hamiltonian systems with saddle-loop. Under quadratic perturbations, it is proved that the perturbed system has at most two limit cycles in the finite plane. The proof relies on a careful analysis of a related Abelian integral.展开更多
THE altered deformation zone type Au (Ag) deposits share an important part from the precious metallicore deposits in the Yunkai area, South China. Their formation is a history of poly-stage evolution. Pre- liminary so...THE altered deformation zone type Au (Ag) deposits share an important part from the precious metallicore deposits in the Yunkai area, South China. Their formation is a history of poly-stage evolution. Pre- liminary source strata, Calidoniam metamorphism, Indosinian-Yanshanian ductile shear deformation andassociated hydrotheraml alteration all play certain roles in the history. This note discusses the geochemical conditional of the hydrothermal fluids during mineralization. Two representative ore deposits, the Pangxidong Ag(Au) deposit and Hetai Au deposits are selectedfor this study. They are hosted in altered ductile shear zones. Wall-rock hydrothermal alteration is bothspatially and temporally associated with the development of the ductile shear system. Silicification occurred throughout the whole alteration process. There are three groups of quartz: thepredeformational quartz, the early stage hydrothermal quartz, and the late stage hydrothermal quartz asso-展开更多
The study of nanocrystalline SnO2 (n-SnO2) and SiO2-doped SnO2 (n-Si-SnO2) samples pre-pared by the sol-gel process showed that SiO2 doping can effectively restrained the growth of nanocrystalline SnO2 grains, thus im...The study of nanocrystalline SnO2 (n-SnO2) and SiO2-doped SnO2 (n-Si-SnO2) samples pre-pared by the sol-gel process showed that SiO2 doping can effectively restrained the growth of nanocrystalline SnO2 grains, thus improving thermal stability of the materials.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29975033) and Guangdong Provincial Natural Science Foundation (Grant No. 001237).
文摘A new method based on the combining of the wavelet theory with the fractal theory and named wavelet fractal peak position method (WFPPM) is introduced to ex-tract the number of the components and the relevant peak positions from overlapping signals in chemistry. The over-lapping signal is first transformed into continuous wavelet transform value of time domain in certain dilation range via continuous wavelet transform (CWT), and then changed into capacity dimensions (Dc). The number of the components and the relevant positions of overlapping peaks can be iden-tified easily according to the change of Dc. An investigation concerning the influence of different dilation ranges on the peak positions extracted by WFPPM is also provided. Stud-ies show that the WFPPM is an efficient tool for extracting the peak positions and identifying the number of peaks from unresolved signals, even when this kind of overlapping is significantly serious. Relative errors of less than 1.0% in peak positions are found when WFPPM is used in the pro- cessing of the cadmium(Ⅱ)-indium(Ⅲ) mixture system. The analytical results demonstrate that the desired peak positions can be extracted conveniently, accurately and rapidly from an unresolved signal via WFPPM. Tremendous developing and applications based on currently reported WFPPM in extracting overlapping signals would be expected in the near future.
基金supported by the National Natural Science Foundation of China(Grant Nos.30230200 and 30170216)by the Fund for Distinguished Young Scholars from the Ministry of Education of China.
文摘Site-specific pseudouridylations of rRNAs and snRNAs are directed by small guide RNAs that usually pos-sess conserved H and ACA motifs and the consensus secon-dary structure consisting of hairpin-hinge-hairpin-tail. In this study, through screening cDNA library, three novel box H/ACA snoRNAs, termed SP12, SP16 and SP20, have been identified from fisson yeast Schizosacchromyces pombe. Each of the small RNAs possesses an ACA-like motif and exhibits secondary structures containing two or three large hairpin- like domains. Although the box H is noncanonical, SP20 can be potentially folded into a typical box H/ACA snoRNA-like structure and is predicted to guide two pseudouridylations, U1208 and U1053, on 18S rRNA. In contrast, SP12 and SP16 display different structures from SP20 and have no antisense elements to rRNAs or snRNAs. Obviously, they are new members of orphan guide snoRNAs whose functions remain elusive. The genes encoded for SP12 and SP16 are both lo-cated in long intergenic regions between protein-coding genes. A post-transcriptional processing for SP16 precursor was demonstrated. Interestingly, SP20 gene is nested inside a very hypothetical ORF, but transcribed in a reverse sense. Northern and RT-PCR analyses could not detect the tran-script from the hypothetical ORF, and therefore exclude the expression of the spurious gene. This is the first example that a genetic locus predicted for protein-coding gene actually encodes a small non-messenger RNA in S. pombe.
基金the National Natural Science Foundation of China (Grant No. 40071084)
文摘The results of sedimentary characteristics, grain-size, clay mineral, C/N and pollen analysis reveal the evolution history of the Shuangchi Maar Lake of Hainan Island as well as the short-term climate variations in tropical areas. It is testified that the Maar sediment system was sensitive in recording the rapid climate changes in the Holocene. These multidisciplinary results demonstrate that the thermal maximum in the Holocene climate lasted from 7200 to 2700 aBP, with several abrupt ephemeral vibrations occurring between 7250-6120 aBP and at around 4460, 3850 and 2700 aBP. In the late Holocene, particularly at ~2700 aBP, a distinct environmental change indicating an important climate transition in the tropical eastern Asia was recorded, probably responding to the enhancement of ENSO phenomena in the Pacific Ocean. In addition, the high-resolution algae record clearly indicates periodical climate fluctuations at 500 a cyclicity during the last 2500 years.
文摘Danxia Landform belongs to red terrestrial clastic rock landform, which is characterized by its red cliffed scarp. The development of Danxia Landform research in China experienced three historic stages, i.e. initial establishment, taking shape and expanding since the concept 'Danxia Landform' raised by Prof. Chen Guoda in 1939. As a new branch of geomorphology, Danxia geomorphology research is now stepping its ripe stage. In the 1990s, the search enters into an unprecedented grand occasion at the prompting of tourism exploit.
文摘By constructing and screening the Schizosac-charomyces pombe nuclear cDNA library, a novel small nu-cleolar RNAs (snoRNA) was identified. The novel snoRNAdisplays structural features typical of C/D box snoRNA fam-ily and possesses a 10-nt-long rRNA antisense element whichis predicted to guide the 2’-O-methylation of the fission yeast 25S rRNA at G940. As expected, the rRNA ribose-methyla-tion site predicted by the novel snoRNA was preciselymapped by a deoxynucleoside triphosphate concentration-dependent primer extension assay. The comparison of func-tional element of guide snoRNAs among eukaryotes reveals that the novel snoRNA is a partial counterpart of the bud-ding yeast snR60 and was termed snR60-II. snR60-II genenested in the intron of a non-coding RNA gene with an un-known function, which is the first example of a yeastsnoRNA encoded in an intron of a non-coding RNA gene.Furthermore, a number of yeast snR60 homologues were also identified from other fungi and fly. Our results reveal thatsnR60 exhibits diverse genomic organization in eukaryotes, implying the high mobility of snR60 gene in the course ofevolution.
文摘The risk of drinking water is greatly concerned because of the large amount of pesticide applied to paddy field and the contamination of drinking water sources due to the runoff. A mathematical model is developed, based on the mass balance, to predict the fate of paddy field pesticides from application, runoff and mixing in a river, taking account of the physical chemical properties and processes of volatilization, degradation, adsorption and desorption. The model is applied to a river basin in Japan to estimate the contaminant level of several popularly used pesticides at the water intakes. The health risk in drinking water induced by each pesticide concerned is estimated and evaluated by comparing with the acceptable daily intake values(ADI) and with that induced by trihalomethanes. An index to evaluate the total risk of all pesticides appearing in water is proposed. The methods for risk management are also discussed.
基金the National Natural Science Foundation of China (No.10101031. No. 10071097). Guangdong Natural Science Foundation (No. 001289)
文摘The authors investigate a kind of degenerate quadratic Hamiltonian systems with saddle-loop. Under quadratic perturbations, it is proved that the perturbed system has at most two limit cycles in the finite plane. The proof relies on a careful analysis of a related Abelian integral.
文摘THE altered deformation zone type Au (Ag) deposits share an important part from the precious metallicore deposits in the Yunkai area, South China. Their formation is a history of poly-stage evolution. Pre- liminary source strata, Calidoniam metamorphism, Indosinian-Yanshanian ductile shear deformation andassociated hydrotheraml alteration all play certain roles in the history. This note discusses the geochemical conditional of the hydrothermal fluids during mineralization. Two representative ore deposits, the Pangxidong Ag(Au) deposit and Hetai Au deposits are selectedfor this study. They are hosted in altered ductile shear zones. Wall-rock hydrothermal alteration is bothspatially and temporally associated with the development of the ductile shear system. Silicification occurred throughout the whole alteration process. There are three groups of quartz: thepredeformational quartz, the early stage hydrothermal quartz, and the late stage hydrothermal quartz asso-
文摘The study of nanocrystalline SnO2 (n-SnO2) and SiO2-doped SnO2 (n-Si-SnO2) samples pre-pared by the sol-gel process showed that SiO2 doping can effectively restrained the growth of nanocrystalline SnO2 grains, thus improving thermal stability of the materials.
