重庆地区紫色土壤镉有效性水平及分异特性研究

通过对重庆地区不同紫色地层发育的紫色土壤系统采样分析有效态镉的含量、影响因素和分异特征,结果表明:有效镉的含量水平和分异值大小顺序为紫色潮土,棕紫泥土,暗紫泥土,灰棕紫泥土,红棕紫泥土,并且显著大于全国背景值0.079mg/kg;通径分析与有效镉影响因子大小顺序为有效Fe,有效Mn,有机质,有效Pb,有效Zn,有效Cu;与有机质和有效Cu,Zn,Fe,Mn,Pb含量呈极显著乘幂关系(r=0.406～0.545);在p=0.01水平,有效Cd与pH值呈极显著指数关系(r=0.406),并且淹水利用使土壤镉有效性提高.

土系分异特性的选取原则以及土系划分方法

土系分异特性的选取应该遵循分异特性的稳定性、空间变异性、主导性、生产性和综合性原则 ;线性回归、主成分分析、相关分析、土壤特性响应时间、变异系数等方法是根据选取土系划分标准的科学定量方法 ,而最有效的土系分异特性选取方法是根据土壤学研究成果和生产实践经验 ;建议华北冲积平原的土系分异特性选择特征土层、特征土层的排列、表层土壤质地和易溶盐含量等。为了使土系划分边界清楚 ,土系划分应采取检索方法。

右江谷地景观格局空间分异特性遥感研究

利用1986年和2006年获取的TM图像,在GIS技术支持下,运用景观生态学原理,选取反应景观空间结构和景观异质性的景观指数,以右江谷地典型区广西平果县为研究区,分析该区近20 a间的景观格局及其动态变化特征。结果表明,1986～2006年间,平果县土地利用变化总趋势是林地、未利用地和居民地面积增加,草地、耕地和水域面积减少;各种景观指数随土地利用变化表现出明显的时空响应,景观多样性变大,景观优势度、破碎度和分维度均变小,表明整体景观朝着良性方向发展。

新疆北疆景观格局空间分异特性研究

本研究利用2001和2012年MODIS土地覆盖类型产品MOD12Q1数据作为信息源,提取新疆北疆常绿针叶林、稀疏植被、农用地、雪和水等各土地利用类型信息。本研究在GIS技术支持下,运用景观生态学原理,选取反映景观空间结构和异质性的景观指数,分析该地区在11年间的景观格局及其动态变化特征。研究结果表明:随着北疆年平均气温的逐年升高,年平均降水的缓慢增加,及年平均大气相对湿度的降低,2012年相比于2001年雪和水的面积减少了5.736×105hm2。草地(主要为一年生短命植物)面积增加了1.43412×107hm2,稀疏植被(以白梭梭为建群种的荒漠植被)面积减少了3.8722×106hm2。景观优势度指数则在该期间增加了0.39,而多样性、破碎度和分维数指数则分别减小了0.39、0.06和0.03。上述变化使得北疆景观格局异质性降低,景观结构趋向单一。在气候和人文两大因子的驱动下,北疆景观格局正发生着明显改变。该变化是否会影响未来"山脉-绿洲-荒漠"这一耦合系统的稳定及可持续发展值得密切关注。

我国耕地等别分异特性及其对耕地保护的影响探究

本文从我国耕地等别分异特性分析入手,分析了我国耕地等别分异特性对耕地保护的影响,并剖析了耕地等别分异特性对耕地保护带来的影响。

中国土壤分类简析

本文依据土壤分类的逻辑与原则,对我国古今土壤分类进行分析,并试图指出其中的不足,为以后土壤分类的发展提供侧面的参考。

Prediction of Subcellular Localization of Eukaryotic Proteins Using Position-Specific Profiles and Neural Network with Weighted Inputs

Subcellular location is one of the key biological characteristics of proteins. Position-specific profiles （PSP） have been introduced as important characteristics of proteins in this article. In this study, to obtain position-specific profiles, the Position Specific lterative-Basic Local Alignment Search Tool （PSI-BLAST） has been used to search for protein sequences in a database. Position-specific scoring matrices are extracted from the profiles as one class of characteristics. Four-part amino acid compositions and lst-7th order dipeptide compositions have also been calculated as the other two classes of characteristics. Therefore, twelve characteristic vectors are extracted from each of the protein sequences. Next, the characteristic vectors are weighed by a simple weighing function and inputted into a BP neural network predictor named PSP-Weighted Neural Network （PSP-WNN）. The Levenberg-Marquardt algorithm is employed to adjust the weight matrices and thresholds during the network training instead of the error back propagation algorithm. With a jackknife test on the RH2427 dataset, PSP-WNN has achieved a higher overall prediction accuracy of 88.4% rather than the prediction results by the general BP neural network, Markov model, and fuzzy k-nearest neighbors algorithm on this dataset. In addition, the prediction performance of PSP-WNN has been evaluated with a five-fold cross validation test on the PK7579 dataset and the prediction results have been consistently better than those of the previous method on the basis of several support vector machines, using compositions of both amino acids and amino acid pairs. These results indicate that PSP-WNN is a powerful tool for subcellular localization prediction. At the end of the article, influences on prediction accuracy using different weighting proportions among three characteristic vector categories have been discussed. An appropriate proportion is considered by increasing the prediction accuracy.

Comparison of Newly Synthetic Hexaploid Wheat with Its Donors on SSR Products

Microsatellites or SSRs as powerful genetic markers have widely been used in genetics and evolutionary biology in common wheat. Because of the high polymorphism, newly synthesized hexaploid wheat has been used in the construction of genetic segregation population for SSR markers, However, data on the evolution of microsatellites during the polyploidization event of hexaploid wheat are limited. In this study, 66 pairs of specific to A/B genome SSR patterns among newly synthesized hexaploid wheat, the donor tetraploid wheat and Aegilops tauschii were compared. The results indicated that most SSR markers were conserved during the polyploidization events of newly synthetic hexaploid wheat, from Triticum turgidum and Ae. tauschii. Over 70% A/B genome specific SSR markers could amplify the SSR sequences from the D genome ofAe. tauschii. Most amplified fragments from Ae, tauschii were detected in synthetic hexaploid at corresponding positions with the same sizes and patterns as in its parental Ae. tauschii. This suggested that these SSR markers, specific for A/B genome in common wheat, could amplify SSR products of D genome besides A/B genome in the newly synthesized hexaploid wheat, that is, these SSR primers specific for A/B genome in common wheat were nonspecific for the A/B genome in the synthetic hexaploid wheat. In addition, one amplified Ae. tauschii product was not detected in the newly synthetic hexaploid wheat. An extra-amplified product was found in the newly synthetic hexaploid wheat. These results suggested that caution should be taken when using SSR marker to genotype newly synthetic hexaploid wheat.

Construction of the Plasmid Reference Molecule for Detection of Transgenic Soybean MON89788

[Objective] The aim was to construct a plasmid reference molecule (PRM) for detection of transgenic soybean MON89788. [Method] the lectin gene sequence,3'-junction and 5'-junction sequence between host plant DNA integrated DNA of MON89788 soybean were amplified independently,and the three fragments were cloned into the cloning vector pMD18-T in order through molecular manipulation method to construct pMD-LM3M5,the applicability of the constructed novel PRM was tested. [Result] Sequencing confirmation result showed that the PRM was 3 700 bp in length,containing 1 029 bp of recombined DNA fragment. The limits of qualitative detection of the PRM were 10 copies. [Conclusion] The PRM constructed in this study was suitable for the identification of MON89788 event.

Seed Morphology and Seedling Variation of Four Ornamental Lupin Pedigrees

[Objective] This study was conducted to reveal seed characteristics, variation and their effects on seedling growth of ornamental lupins. [Method] The phenotypic characteristics and germination rate of the seeds of four excellent lupin pedigrees were measured, and then their correlations with seeding growth were analyzed. [Result] There were abundant variations among the four ornamental lupin pedigrees. Pink seeds had the largest volume and red seeds had the largest 1 000seed weight. The variation coefficients for the seed morphological traits among the four pedigrees ranged from 2.97% to 14.34%. Seed specific weight and 1 000-seed weight could be used as important indicators for selection in breeding because of their higher variability. Seed weight variation of ornamental lupin was mainly depen- dent on seed width variation. There was small variation in seed length. The seeds of the four ornamental lupin pedigrees started to germinate one day after sowing, and the germination period was 5 d. Germination rate coefficient and germination index of pink and red seeds were higher than those of blue seeds, but blue seeds had the largest germination rate. 1 000-seed weight shared significantly positive correlations with seed germination rate, germination potential and seedling retention rate. Round and large seeds had some advantages in germination. Full seeds had higher germination rate and speed, and seedling retention rate. There was a significant relationship between seed length-width ratio and the number of leaflets of seedlings. [Conclusion] The results provided references for the evaluation of seed phenotypic diversity and breeding research of ornamental lupins.

Molecular characteristics and stages of chronic hepatitis B virus infection

Hepatitis B virus (HBV) is a common viral pathogen that causes a substantial health burden worldwide. Remarkable progress has been made in our understanding of the natural stages of chronic HBV infection. A dynamic balance between viral replication and host immune response is pivotal to the pathogenesis of liver disease. Knowledge of the HBV genome organization and replication cycle can unravel HBV genotypes and molecular variants, which contribute to the heterogeneity in outcome of chronic HBV infection. Most HBV infections are spontaneously resolved in immunocompetent adults, whereas they become chronic in most neonates and infants at a great risk of developing complications such as cirrhosis and hepatocellular carcinoma (HCC). Those with chronic HBV infection may present in one of the four phases of infection: immune tolerance, immune clearance [hepatitis B eantigen (HBeAg)-positive chronic hepatitis B (CHB)], inactive carrier state, and reactivation (HBeAg-negative CHB). Understanding the dynamic nature of chronic HBV infection is crucial in the management of HBV carriers. Long-term monitoring and optimal timing of antiviral therapy for chronic HBV infection help to prevent progression of HBV-related liver disease to its later stage, particularly in patients with higher risk markers of HCC, such as serum DNA concentration, HBeAg status, serum aminotransferase, HBV genotypes, and pre-core or core mutants.

Molecular cloning and mRNA expression analysis of myosin heavy chain(MyHC)from fast skeletal muscle of grass carp,Ctenopharyngodon idella

The myosin heavy chain(MyHC)is one of the major structural and contracting proteins of muscle.We have isolated the cDNA clone encoding MyHC of the grass carp,Ctenopharyngodon idella. The sequence comprises 5 934 bp,including a 5 814 bp open reading frame encoding an amino acid sequence of 1 937 residues.The deduced amino acid sequence showed 69%homology to rabbit fast skeletal MyHC and 73%–76%homology to the MyHCs from the mandarin fish,walleye pollack,white croaker,chum salmon,and carp.The putative sequences of subfragment-1 and the light meromyosin region showed 61.4%–80%homology to the corresponding regions of other fish MyHCs.The tissue-specific and developmental stage-specific expressions of the MyHC gene were analyzed by quantitative real-time PCR.The MyHC gene showed the highest expression in the muscles compared with the kidney,spleen and intestine.Developmentally,there was a gradual increase in MyHC mRNA expression from the neural formation stage to the tail bud stage.The highest expression was detected in hatching larva.Our work on the MyHC gene from the grass carp has provided useful information for fish molecular biology and fish genomics.

Effects of Normalized Difference Vegetation Index and Related Wavebands′ Characteristics on Detecting Spatial Heterogeneity Using Variogram-based Analysis

Spatial heterogeneity is widely used in diverse applications, such as recognizing ecological process, guiding ecological restoration, managing land use, etc. Many researches have focused on the inherent scale multiplicity of spatial heterogeneity by using various environmental variables. How these variables affect their corresponding spatial heterogeneities, however, have received little attention. In this paper, we examined the effects of characteristics of normalized difference vegetation index （NDVI） and its related bands variable images, namely red and near infrared （NIR）, on their corresponding spatial heterogeneity detection based on variogram models. In a coastal wetland region, two groups of study sites with distinct fractal vegetation cover were tested and analyzed. The results show that： l） in high fractal vegetation cover （H-FVC） area, NDV! and NIR variables display a similar ability in detecting the spatial he- terogeneity caused by vegetation growing status structure; 2） in low fractal vegetation cover （L-FVC） area, the NIR and red variables outperform NDVI in the survey of soil spatial heterogeneity; and 3） generally, NIR variable is ubiquitously applicable for vegetation spatial heterogeneity investigation in different fractal vegetation covers. Moreover, as variable selection for remote sensing applications should fully take the characteristics of variables and the study object into account, the proposed variogram analysis method can make the variable selection objectively and scientifically, especially in studies related to spatial heterogeneity using remotely sensed data.

Is extended biopsy protocol justified in all patients with PSA≥20ng/mL?

The aim of this study was to investigate whether it was necessary to increase the number of cores at initial prostate biopsy with patients of prostate-specific antigen （PSA） ≥ 20 ng/mL and to explore an appropriate individualized transrectal ultrasonograhpy （TRUS）-guided prostate biopsy for the detection of prostate cancer in men suspicious of prostate cancer. Methods： A total of 115 patients with PSA ≥ 20 ng/mL and suspicious of prostate cancer were prospectively randomized to perform TRUS-guided biopsy. Patients were randomized to a ＂6 ＋ X＂ cores or a ＂10 ＋ X＂ cores protocol. The primary end point was cancer detection rate. Secondary end points were cancer characteristics, rate of complications and the level of pain experienced by patients during TRUS-guided prostate biopsy. Results： Preoperative variables were similar in both groups. The overall prostate cancer detection rate was 73.9%. The ＂10 ＋ X＂ cores strategy increased cancer detection rate only 9.7% in patients with PSA ≥ 20 ng/mL but 〈 50 ng/mL, while there was no difference between the two strategies for cancer detection in patients with PSA ≥ 50.1 ng/mL. The number of extended biopsy cores and pain score of extended biopsy in prostate cancer patients increased significantly （P 〈 0.001）. Conclusion： Our findings suggest that there is no significant advantage in using extended biopsy protocol in all patients with PSA≥20 ng/mL.

GPCR A2AAR Agonist Binding and Induced Conformation Changes of Functional Switches

Agonist binding of A2A adenosine receptor （A2AAR） shows protective effects against inflammatory and immune. Efforts are exerted in understanding the general mechanism and developing A2AAR selectively binding agonists. Using molecular dynamics （MD） simula- tions, we have studied the interactions between A2AAR and its agonist （adenosine）, and analyzed the induced dynamic behaviors of the receptor. Key residues interacting with adenosine are identified： A63^2.61,I66^2.64,V84^3.32,L85^3.33,T88^3.36,F168^5.29,M177^5.38,L249^6.51,H250^6.52 and N253^6.55 interacting with adenosine with affinities larger than 0.5 kcal/mol. Moreover, no interaction between adenosine and L167^5.28 is observed, which supports our previous findings that L1675^5.28 is an antagonist specific binding reside. The dynamic be- haviors of agonist bound A2AAR are found to be different from apo-A2AAR in three typical functional switches： （i） tight ＂ionic lock＂ forms in adenosine-A2AAR, but it is in equilibrium between formation and breakage in apo-A2AAR; （ii） the ＂rotamer toggle switch＂, T88^3.36/F242^6.44/W246^6.48, adopted different rotameric conformations in adenosin-A2AAR and apo-A2AAR; （iii） adenosine-A2AAR has a flexible intracellular loop 2 （IC2） and s-helical IC3, while apo-A2AAR preferred s-helical IC2 and flexible IC3. Our results indicate that agonist binding induced different conformational rearrangements of these characteristic functional switches in adenosine-A2AAR and apo-A2AAR.

A new identification method for five species of oysters in genus Crassostrea from China based on high-resolution melting analysis

The high phenotypic plasticity in the shell of oysters presents a challenge during taxonomic and phylogenetie studies of these economically important bivalves. However, because DNA can exhibit marked differences among morphologically similar species, DNA barcoding offers a potential means for oyster identification. We analyzed the complete sequences of the cytochrome oxidase subunit I （COI） of five common Crassostrea species in China （including Hong Kong oyster C. hongkongensis, Jinjiang oyster C. ariakensis, Portuguese oyster C. angulata, Kumamoto oyster C. sikamea, and Pacific oyster C. gigas） and screened for distinct fragments. Using these distinct fragments on a high-resolution melting analysis platform, we developed an identification method that does not rely on species-specific PCR or fragment length polymorphism and is efficient, reliable, and easy to visualize. Using a single pair of primers （Oyster- COI-1）, we were able to successfully distinguish among the five oyster species. This new method provides a simple and powerful tool for the identification of oyster species.

Experimental investigation on combustion and unregulated emission characteristics of butanol-isomer/gasoline blends

Effects of butanol isomers on characteristics of combustion and emission were studied on PFI SI engine. Experiments were operated under the condition of 3 and 5 bar brake mean effective pressure (BMEP) engine loads and different equivalence ratios (φ=0.83-1.25) with engine speed of 1200 r/min using blends made of 70 vol.% gasoline and 30 vol.% butanol isomers (N30, S30, I30 and T30). The results indicated that compared with gasoline, all butanol isomer blends have higher cylinder pressure. N30 has the highest and most advanced peak pressure, and T30 shows a higher brake specific fuel consumption (BSFC) and lower brake thermal efficiency (BTE). N30 presents a lower UHC emissions and I30 has slightly higher CO emissions than other blends. For unregulated emissions, compared with gasoline, butanol isomer blends have higher acetaldehyde, and N30 produces a higher emission of 1,3-butadiene than other blends. A reduction in benzene, toluene, ethylbenzene and xylene (BTEX) has been found with butanol isomer blends.

Meta-analysis of capsule endoscopy in patients diagnosed or suspected with esophageal varices

AIM:To review the literature on capsule endoscopy(CE) for detecting esophageal varices using conventional esophagogas troduodenoscopy(EGD)as the standard. METHODS:A strict literature search of studies comparing the yield of CE and EGD in patients diagnosed or suspected as having esophageal varices was conducted by both computer search and manual search.Data were extracted to estimate the pooled diagnostic sensitivity and specificity. RESULTS:There were seven studies appropriate for meta-analysis in our study,involving 446 patients. The pooled sensitivity and specificity of CE for detecting esophageal varices were 85.8%and 80.5%, respectively.In subgroup analysis,the pooled sensitivity and specificity were 82.7%and 54.8%in screened patients,and 87.3%and 84.7%in the screened/ patients under surveillance,respectively. CONCLUSION:CE appears to have acceptable sensitivity and specificity in detecting esophageal varices.However,data are insufficient to determine the accurate diagnostic value of CE in the screen/ surveillance of patients alone.

Allometric equations of select tree species of the Tibetan Plateau, China

The Tibetan forest is one of the most important national forest zones in China. Despite the potentially important role that Tibetan forest will play in the Earth?s future carbon balance and climate regulation, few allometric equations exist for accurately estimating biomass and carbon budgets of this forest. In the present study, allometric equations,both species-specific and generic, were developed relating component biomass(DW) to diameter at breast height(DBH) and tree height(H) for six most common tree species in Tibetan forest. The 6 species were Abies georgei Orr., Picea spinulosa(Griff.)Henry, Pinus densata Mast., Pinus yunnanensis Franch., Cypresses funebris Endl. and Quercus semecarpifilia Smith.. The results showed that, both DBH-only and DBH2 H based species-specific equations showed a significant fit(P<0.05) for all tree species and biomass components. The DBH-only equations explained more than 80% variability of the component biomass and total biomass, adding H as a second independent variable increased the goodness of fit, while incorporating H into the term DBH2 H decreased the goodness of fit. However, not all DBH-H combined equations showed a significant fit(P<0.05) for all tree species and biomass components. Hence, the suggested species-specific allometric equations for the six most common tree species are of the form ln(DW) = c + αln(DBH). The generalized equations of mixed coniferous component biomass against DBH, DBH2 H and DBH-H also showed a significant fit(P<0.05) for all biomass components. However, due to significant species effect, the relative errors of the estimates were very high. Hence, generalized equations should only be used when there are too many different tree species, or there is no species-specific model of the same species or similar growth form in adjacent area.

Shear-wave Splitting in the Crust beneath Shandong and Its Adjacent Area

Based on the seismic data of near-field source from the Shandong Digital Seismic Network,this study obtained the shear-wave splitting parameters from multiple stations. The results show that dominant directions of polarizations of fast shear-waves reflect the spatial distribution characteristics of tectonic stress in this area,CHD and LIS stations show 2 dominant directions,and reveals that the crustal seismic anisotropy in the Shandong area is constrained by the regional stress background,local failure and structure.