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High separation sharpness of hydrocyclones is an ultimate goal for the classification process and has attracted considerable attention. The existence of some special flow patterns, such as short-circuit flow and circulation flow, play an important role in the separation process and have not been clearly understood. This paper presents a numerical study of the effects of vortex finder wall thickness on the flow field and separation performance. More importantly, the formations and effects of short-circuit flow, circulation flow, and axial velocity wave zone (AVWZ) were investigated and understood. The simulation results were analyzed in terms of pressure drop, water velocity, separation efficiency, and particle distribution. The results indicate that a thicker vortex finder wall could reduce pressure drop, tangential velocity magnitudes, and the flow rates of both short-circuit flow and circulation flow but increase the fluctuations of axial and radial velocities especially beneath the vortex finder where the AVWZ is formed. The leakage effect of short-circuit flow on sub-coarse particles is less significant than the fluctuation effect of AVWZ. The circulation flow in pre-separation space is beneficial to re-separate the sub-fine and sub-coarse particles to improve the separation sharpness. Consequently, the hydrocyclone with a thin-walled vortex finder is more beneficial for efficient classification.

Inulin has been used as a prebiotic to alleviate glucose and lipid metabolism disorders in mice and humans by modulating the gut microbiota. However, the mechanism underlying the alleviation of metabolic disorders by inulin through interactions between the gut microbiota and host cells is unclear. We use ob/ob mice as a model to study the effect of inulin on the cecal microbiota by 16S rRNA gene amplicon sequencing and its interaction with host cells by transcriptomics. The inulin-supplemented diet improved glucose and lipid metabolism disorder parameters in ob/ob mice, alleviating fat accumulation and glucose intolerance. The α diversity of gut microbial community of ob/ob mice was reduced after inulin treatment, while the β diversity tended to return to the level of wild type mice. Interestingly, Prevotellaceae UCG 001 (family Prevotellaceae) was obviously enriched after inulin treatment. A comparative analysis of the gene expression profile showed that the cecal transcriptome was changed in leptin gene deficiency mice, whereas the inulin-supplemented diet partially reversed the changes in leptin gene-related signaling pathways, especially AMPK signaling pathway, where the levels of gene expression became comparable to those in wild type mice. Further analysis indicated that Prevotellaceae UCG 001 was positively correlated with the AMPK signaling pathway, which was negatively correlated with markers of glycolipid metabolism disorders. Our results suggest that the inulin-supplemented diet alleviates glucose and lipid metabolism disorders by partially restoring leptin related pathways mediated by gut microbiota. Keywords: Prebiotics, Gut microbiota, Obesity, Transcriptome, Metabolic disorders

Land degradation is a global environmental problem that threatens human safety and socioeconomic development. In order to alleviate severe soil erosion, China has implemented historically unprecedented large-scale afforestation. In this study, we selected the most severely eroded Loess Plateau as a case, to assess the effectiveness of soil and water conservation (SWC) efforts based on the Revised Universal Soil Loss Equation. In addition, the underlying drivers for soil erosion changes and hydrological effects of SWC were investigated, and finally the potential policy implications of our findings were discussed. The soil erosion intensity from 2000 to 2015 was weakened largely due to favorable climate conditions and SWC efforts, which promoted vegetation restoration and enhanced soil retention. However, there was a significant trade-off between water provision and soil retention functions. The excessively artificial afforestation reduced sediment yield but depleted surface runoff. Furthermore, artificial afforestation and increasing irrigation water consumption overused groundwater resources and finally lowered groundwater table. The SWC efforts characterized by artificial afforestation induced soil moisture declining, particularly for the conversion type of farmland to forest/shrub. Our results suggested that afforestation might be a poor choice in arid and semiarid regions, because it did not consider local precipitation conditions, and have exacerbated water shortages and offset SWC efforts. Therefore, the future ecological restoration efforts should be transformed from simple species-based measures to optimal plant species combinations to minimize the tradeoff between water yield and soil retention. The strategies for ecological restoration of drylands should also account for water balance to ensure effectiveness and sustainability.

Understanding the driving forces for alpine vegetation variations at different permafrost degrading stages is important when the Tibetan Plateau is experiencing climate warming. We applied the modified Frost Number model to simulate frozen ground distributions in the Tibetan Plateau and calculated the maximum thawing depth by the Stefan approach. We classified the simulated frozen ground into three subzones: seasonal frozen ground zone, changing zone, and permafrost zone. We evaluated the effects of precipitation, air temperature, and maximum thawing depth on Normalized Difference Vegetation Index (NDVI) in the subzones across five different stages from 1982 to 2012. The results show that permafrost zone, changing zone, and seasonal frozen ground zone account for about 30.6 percent, 23.3 percent, and 46.1 percent of the study area, respectively. Over the five stages, permafrost areas decreased at fast, slow, fastest, and then slowest rate from stage1 to stage 5, and the large continuous permafrost area has been degraded into pieces. Precipitation is strongly correlated with NDVI and contributes most `to the changes of NDVI. Maximum thawing depth and particularly air temperature show a much smaller correlation and contribute less to the variation rate of NDVI. The findings will have broad applications in investigating the impact of climate and environment changes on alpine vegetation variations in the Tibetan Plateau.

Background An increase in the incidence of central venous catheter (CVC)-related thrombosis (CRT) has been reported in pediatric intensive care patients over the past decade. Risk factors for the development of CRT are not well understood, especially in children. The study objective was to identify potential clinical risk factors associated with CRT with novel fusion machine learning models. Methods Patients aged 0–18 who were admitted to intensive care units from December 2015 to December 2018 and underwent at least one CVC placement were included. Two fusion model approaches (stacking and blending) were used to build a better performance model based on three widely used machine learning models (logistic regression, random forest and gradient boosting decision tree). High-impact risk factors were identified based on their contribution in both fusion artificial intelligence models. Results A total of 478 factors of 3871 patients and 3927 lines were used to build fusion models, one of which achieved quite satisfactory performance (AUC = 0.82, recall = 0.85, accuracy = 0.65) in 5-fold cross validation. A total of 11 risk factors were identified based on their independent contributions to the two fusion models. Some risk factors, such as D-dimer, thrombin time, blood acid-base balance-related factors, dehydrating agents, lymphocytes and basophils were identified or confirmed to play an important role in CRT in children. Conclusions The fusion model, which achieves better performance in CRT prediction, can better understand the risk factors for CRT and provide potential biomarkers and measures for thromboprophylaxis in pediatric intensive care settings.

Background: Nitrosition of tobacco pyridine alkaloids by nitrate-derived NOx is the origin of tobacco-specifc nitrosamines (TSNAs) formed in tobacco, which are among the most notable toxicants present in tobacco products and smoke. Burley tobacco is particularly susceptible to TSNA formation because the cultivars exhibit a chloroplast-deficient and nitrogen-use-defciency phenotype which results in high accumulation of nitrate. Strategies to lower nitrate levels in tobacco could produce a corresponding decrease in TSNAs accumulation in leaves. Previous studies have showed that grafting with high nitrogen use efficiency rootstock was able to improve the nitrogen utilization of flue-cured tobacco. In this study, a reciprocativel grafting experiment has been conducted with two varieties of different tobacco types (burley tobacco ‘Eyan No.1’ and flue-cured tobacco ‘K326’) to investigate whether replacing burley tobacco root with flue-cured tobacco by grafting can enhance pigment biosynthesis and photosynthesis parameters and reduce nitrate content of burley tobacco leaves, and to explore the corresponding mechanism. Results: The results showed that compared with the self-rooted burley tobacco seedlings, grafting significantly increased the pigment content, net photosynthesis, biomass, total soluble sugar, reducing sugar, nitrate reductase activity, glutamine synthetase activities, NH4-N and soluble protein content of the leaves of Eyan No.1 while decreased the nitrate content and NO3-N/TN. Interestingly, transcription level analysis suggested that replacing burley tobacco root with flue-cured tobacco by grafting was able to up-regulate the genes involved in starch and sucrose metabolism, porphyrin and chlorophyll metabolism, carbon fixation in photosynthetic organism metabolism, carotenoid biosynthesis and nitrogen metabolism of burley tobacco leaves. In addition, the PPI network revealed gene_68511, gene_35043 and gene_77508 had higher degrees via replacing burley tobacco root with flue-cured tobacco, which might be hub proteins to reduce nitrate accumulation. Conclusions: In conclusion, grafting with high nitrogen use efficiency rootstock provided an exceptionally promising means of nitrate reduction in burley tobacco leaf , which is a principle precursor of TSNAs, due to the improvement of photosynthesis and nitrogen metabolism in the scion.

Drought causes not only the decrease of tobacco yield and quality, but also the lowering of net photosynthetic rate, leading to reactive oxygen species accumulation and even the death of plants. Salicylic Acid is involved in regulating many plant physiological processes and has increasingly been applied to improve tolerance in plants exposed to drought stress. To explore the regulating mechanism of SA, flue-cured tobacco K326 was used in the hydroponic experiments to design PEG drought stress. The photosynthetic characteristics, antioxidant enzymes activities and osmotic regulatory substances contents of tobacco seedlings under drought stress were investigated after 0.3 mmol L-1 SA treatment. Transcriptome sequencing and GO/KEGG analysis were also performed. The main results showed that SA-applied greatly increased the activities of SOD, POD, CAT activity, Pn, proline and soluble protein by 44.27%, 50.18%, 26.23%, 45.74%, 34.67% and 24.91% while reduced the MDA content by 23.89%. GO and KEGG analysis showed that SA treatment was able to up-regulate the genes involved in photosynthesis, carbon metabolism, porphyrin and chlorophyll metabolism, photosynthesis-antenna proteins. The conclusion is that SA application would effectively improve the ability of pigment biosynthesis and photosystem repair of tobacco under drought conditions, thus enhance the photosynthesis, reduce the accumulation of ROS and increase drought resistance, which would provide a measure for alleviating the damage of tobacco caused by drought stress.

Nitrate is an important precursor of tobacco-specific nitrosamines (TSNAs) and a remarkable difference in nitrate accumulation between lamina and midrib of flue-cured tobacco has long been observed. However, the physiological and molecular mechanisms underpinning this difference remain poorly understood. In this study, physiological and genetic factors impacting nitrate accumulation were identified in pot experiments using flue-cured tobacco K326 with contrasting nitrate content between lamina and midrib. The results showed that three times higher NO3-N content was observed in midrib than that in the lamina, along with lower pigment, NH4-N content, nitrate reductase activity (NRA), sucrose synthetase activity (SSA), and glutamine synthetase activity (GSA) in midrib. Transcriptome analysis revealed that expression of genes involved in porphyrin and chlorophyll metabolism, carotenoid biosynthesis, photosynthesis-antenna proteins, photosynthesis, carbon fixation in photosynthetic organisms, starch and sucrose metabolism, nitrogen metabolism, and biosynthesis of amino acids were significantly lower in midrib than in lamina. qRT-PCR results showed that the expression level of nitrate transporter genes LOC107782967, LOC107806749, LOC107775674, LOC107829632, LOC107799198, LOC107768465 decreased by 2.74, 1.81, 49.5, 3.5, 2.64 and 2.96-folds while LOC107789301 increased by 8.23-folds in midrib but not in lamina. Reduced chlorophyll content might result in low carbohydrate formation which is the source of energy and carbon skeleton supply, then the low capacity of nitrogen reduction, assimilation and transportation, and the poor ability of nitrate reallocation but the high capacity of accumulation might lead to nitrate accumulation in midrib. The results laid the foundation for reducing nitrate content and TSNA formation in tobacco midribs and their products.

Structural analysis of host–pathogen protein complexes remains challenging, largely due to their structural heterogeneity. Here, we describe a pipeline for the structural characterization of these complexes using integrative structure modeling based on chemical cross-links and residue–protein contacts inferred from mutagenesis studies. We used this approach on the HIV-1 Vif protein bound to restriction factor APOBEC3G (A3G), the Cullin-5 E3 ring ligase (CRL5), and the cellular transcription factor Core Binding Factor Beta (CBFβ) to determine the structure of the (A3G-Vif-CRL5-CBFβ) complex. Using the MS-cleavable DSSO cross-linker to obtain a set of 132 cross-links within this reconstituted complex along with the atomic structures of the subunits and mutagenesis data, we computed an integrative structure model of the heptameric A3G-Vif-CRL5-CBFβ complex. The structure, which was validated using a series of tests, reveals that A3G is bound to Vif mostly through its N-terminal domain. Moreover, the model ensemble quantifies the dynamic heterogeneity of the A3G C-terminal domain and Cul5 positions. Finally, the model was used to rationalize previous structural, mutagenesis and functional data not used for modeling, including information related to the A3G-bound and unbound structures as well as mapping functional mutations to the A3G-Vif interface. The experimental and computational approach described here is generally applicable to other challenging host–pathogen protein complexes., Graphical Abstract, Highlights • Integrative modeling using cross-links enables modeling of heterogeneous complexes. • A pipeline that streamlines modeling of host–pathogen complexes is presented. • The A3G-VifHIV-1-CRL5-CBFβ integrative structure in solution is determined. • The structure shows how Vif recruits A3G and the complex structural dynamics., In Brief We present a pipeline that streamlines cross-linking mass spectrometry (XL-MS) data collection, data analysis, and integrative modeling of host–pathogen complexes. Using XL-MS, known atomic structures, and functional genetic data, we determined an integrative structure of the HIV-human A3G-CRL5-Vif-CBFβ complex. This structure illustrates HIV-1 Vif interaction with A3G and captures the structural dynamics and flexibility of the entire A3G-CRL5-Vif-CBFβ complex.

Salmonella enterica remains one of the leading causes of foodborne bacterial disease. Retail meat is a major source of human salmonellosis. However, comparative genomic analyses of S. enterica isolates from retail meat from different sources in China are lacking. A total of 341 S. enterica strains were isolated from retail meat in sixteen districts of Beijing, China, at three different time points (January 1st, May 1st, and October 1st) in 2017. Comparative genomics was performed to investigate the genetic diversity, virulence and antimicrobial resistance gene (ARG) profiles of these isolates. The most common serotype was S. Enteritidis (203/341, 59.5%), which dominated among isolates from three different time points during the year. Laboratory retesting confirmed the accuracy of the serotyping results predicted by the Salmonella In Silico Typing Resource (SISTR) (96.5%). The pangenome of the 341 S. enterica isolates contained 13,931 genes, and the core genome contained 3,635 genes. Higher Salmonella phage 118970 sal3 (219/341, 64.2%) and Gifsy-2 (206/341, 60.4%) prevalence contributed to the diversity of the accessory genes, especially those with unknown functions. IncFII(S), IncX1, and IncFIB(S) plasmid replicons were more common in these isolates and were major sources of horizontally acquired foreign genes. The virulence gene profile showed fewer virulence genes associated with type III secretion systems in certain isolates from chicken. A total of 88 different ARGs were found in the 341 isolates. Three beta-lactamases, namely, blaCTX–M–55 (n = 15), blaCTX–M–14 (n = 11), and blaCTX–M–65 (n = 11), were more prevalent in retail meats. The emergence of qnrE1 and blaCTX–M–123 indicated a potential increase in the prevalence of retail meats. After the prohibition of colistin in China, three and four isolates were positive for the colistin resistance genes mcr-1.1 and mcr-9, respectively. Thus, we explored the evolution and genomic features of S. enterica isolates from retail meats in Beijing, China. The diverse ARGs of these isolates compromise food security and are a clinical threat.

Purpose Apoptosis of the retinal ganglion cells (RGCs) can cause irreversible damage to visual function after retinal ischemia reperfusion injury (RIR). Using a lncRNA chip assay, we selected lncRNA Ttc-209 and characterized its role in RGCs during ischemia reperfusion (I/R)-induced apoptosis. Methods We created an ischemic model of RGCs by applying Hank's balanced salt solution containing 10 µM antimycin A and 2 µM calcium ionophore for 2 hours. RIR was induced in mice by elevating the intraocular pressure to 120 mm Hg for 1 hour by cannulation of the cornea; this was followed by reperfusion. Real-time quantitative PCR was used to detect the expression levels of long noncoding RNA (lncRNA), microRNA (miRNA), and target gene mRNA. Western blotting, flow cytometry, immunofluorescent staining, and TUNEL assays were performed to detect cell apoptosis. Dual-luciferase reporter assays and FISH were used to identify endogenous competitive RNA (ceRNA) mechanisms that link lncRNAs, miRNAs, and target genes. We also used scotopic electroretinography examinations to evaluate visual function in treated mice. Results lncRNA Ttc3-209 was significantly upregulated after I/R injury and played a proapoptotic role in RGCs during I/R-induced apoptosis. Mechanistically, lncRNA Ttc3-209 is a ceRNA that competitively binds to miR-484 and upregulates the translation of its target (Wnt8a mRNA), thus promoting apoptosis in RGCs. Conclusions Reducing the expression of lncRNA Ttc3-209 had a protective effect against apoptosis in RGCs. This may provide a new therapeutic option for the prevention of RGC apoptosis in response to RIR injury.

A numerical model is proposed to calculate both the contact pressure and the friction torque (FT) of the friction components considering the spline friction in a wet multidisc clutch, which is verified by the bench test. The results indicate that the spline friction of components is an important factor causing the axial attenuation of contact pressure on friction pairs. As the applied pressure increases, the attenuation amplitude of contact pressure increases gradually. In addition, the average single-pair FT decreases with the increasing number of friction pairs, thus leading to the decrease of the growth rate of total FT. Therefore, when the number of friction pairs reaches a certain number, it is not reliable to obtain a good torque enhancement, indicating that the effect of spline friction needs to be weakened to reduce the attenuation of contact pressure.

Background: Although significant correlations have been observed between air pollutants and the development of pulmonary tuberculosis (PTB) in many developed countries, data are scarce for developing and highly polluted regions. Method: A combined Poisson generalized linear regression–distributed lag nonlinear model was used to determine the associations between long-term exposure (2005–2017) to air pollutants and the risk of PTB in the Beijing–Tianjin–Hebei region. Results: The monthly PTB cases exhibited a fluctuating downward trend. For each 10 μg/m3 increase in concentration, the maximum lag-specific risk and cumulative relative risk (RR) were 1.011 (95% confidence interval (CI): 1.0091.012, lag: 3 months) and 1.042 (1.036–1.048, 5 months) for PM2.5, and 1.023 (1.015–1.031, 0 months) and 1.041 (1.026–1.055, 2 months) for NO2. The risk of PTB was negatively correlated with O3 exposure, and the minimum lag-specific risk and cumulative RR were 0.991 (95% CI: 0.987–0.994, lag: 0 months) and 0.974 (0.968–0.981, 4 months), respectively. No age-dependent effects were observed. Conclusions: Our results revealed potential associations between outdoor exposure to PM2.5, NO2, and O3 and the risk of PTB. Further research should explore the corresponding interactions and potential mechanisms.

Activation-induced cytidine deaminase (AID) catalyzes the deamination of deoxycytidines within Immunoglobulin (Ig) genes to induce somatic hypermutation (SHM) and class switch recombination (CSR) 1,2. AID-induced deoxyuracils within Ig loci are recognized and processed by subverted base excision and mismatch repair pathways that ensure a mutagenic outcome in B lymphocytes 3–8. However, it is unclear why DNA repair pathways that remove deoxyuracil from DNA are not efficient at faithfully repairing AID-induced lesions. Here, we identified through a genome-wide CRISPR screen that FAM72A, a protein with no ascribed function, is a major determinant for the error-prone processing of deoxyuracil. Fam72a-deficient CH12F3-2 B cells and primary B cells from Fam72a−/− mice have reduced CSR and SHM frequencies. The SHM spectrum in B cells from Fam72a−/− mice is opposite to that observed in Ung2−/− mice 9, suggesting that UNG2 is hyperactive in FAM72A-deficient cells. Indeed, FAM72A binds to UNG2 resulting in reduced UNG2 activity, and significantly reduced protein levels in the G1 phase, coinciding with peak AID activity. This effect leads to increased genome-wide deoxyuracils in B cells. By antagonizing UNG2, FAM72A therefore increases U•G mispairs that engage mutagenic mismatch repair promoting error-prone processing of AID-induced deoxyuracils. This work shows that FAM72A bridges base-excision repair and mismatch repair to modulate antibody maturation.

Salmonella enterica remains one of the leading causes of foodborne bacterial disease. Retail meat is a major source of human salmonellosis. However, comparative genomic analyses of S. enterica isolates from retail meat from different sources in China are lacking. A total of 341 S. enterica strains were isolated from retail meat in sixteen districts of Beijing, China, at three different time points (January 1st, May 1st, and October 1st) in 2017. Comparative genomics was performed to investigate the genetic diversity, virulence and antimicrobial resistance gene (ARG) profiles of these isolates. The most common serotype was S. Enteritidis (203/341, 59.5%), which dominated among isolates from three different time points during the year. Laboratory retesting confirmed the accuracy of the serotyping results predicted by the Salmonella In Silico Typing Resource (SISTR) (96.5%). The pangenome of the 341 S. enterica isolates contained 13,931 genes, and the core genome contained 3,635 genes. Higher Salmonella phage 118970 sal3 (219/341, 64.2%) and Gifsy-2 (206/341, 60.4%) prevalence contributed to the diversity of the accessory genes, especially those with unknown functions. IncFII(S), IncX1, and IncFIB(S) plasmid replicons were more common in these isolates and were major sources of horizontally acquired foreign genes. The virulence gene profile showed fewer virulence genes associated with type III secretion systems in certain isolates from chicken. A total of 88 different ARGs were found in the 341 isolates. Three beta-lactamases, namely, blaCTX–M–55 (n = 15), blaCTX–M–14 (n = 11), and blaCTX–M–65 (n = 11), were more prevalent in retail meats. The emergence of qnrE1 and blaCTX–M–123 indicated a potential increase in the prevalence of retail meats. After the prohibition of colistin in China, three and four isolates were positive for the colistin resistance genes mcr-1.1 and mcr-9, respectively. Thus, we explored the evolution and genomic features of S. enterica isolates from retail meats in Beijing, China. The diverse ARGs of these isolates compromise food security and are a clinical threat.

In this paper, a frequency-domain dual component computation diversity (FDC-CD) scheme is proposed based on generalized hybrid carrier (GHC) system. It is used to improve the transmission reliability and diversity gain of traditional orthogonal frequency division multiplexing (OFDM) systems. By introducing GHC into the diversity algorithm, the energy distribution of the transmitted signal is averaged, and the forward component and the reverse component after transformation are backup to each other, thus improving the anti-fading capability of the system. In this paper, the principle and signal processing of FDC-CD are explained, and the simulation analysis is given under the typical channel. The simulation results show that the FDC-CD algorithm can improve the BER performance by more than 3dB at $10^{-3}$ and diversity gain by more than 0.40. The improvement is more obvious in the channel dominated by multipath fading.

The authors retract their recent published article [...]

Clostridium perfringens is associated with a variety of diseases in both humans and animals. Recent advances in genomic sequencing make it timely to re-visit this important pathogen. Although the genome sequence of C. perfringens was first determined in 2002, large-scale comparative genomics with isolates of different origins is still lacking. In this study, we used whole-genome sequencing of 45 C . perfringens isolates with isolation time spanning an 80‐year period and performed comparative analysis of 173 genomes from worldwide strains. We also conducted phylogenetic lineage analysis and introduced an openness index (OI) to evaluate the openness of bacterial genomes. We classified all these genomes into five lineages and hypothesized that the origin of C. perfringens dates back to ~80 000 years ago. We showed that the pangenome of the 173 C . perfringens strains contained a total of 26 954 genes, while the core genome comprised 1020 genes, accounting for about a third of the genome of each isolate. We demonstrated that C. perfringens had the highest OI compared with 51 other bacterial species. Intact prophage sequences were found in nearly 70.0 % of C. perfringens genomes, while CRISPR sequences were found only in ~40.0 %. Plasmids were prevalent in C. perfringens isolates, and half of the virulence genes and antibiotic resistance genes (ARGs) identified in all the isolates could be found in plasmids. ARG-sharing network analysis showed that C. perfringens shared its 11 ARGs with 55 different bacterial species, and a high frequency of ARG transfer may have occurred between C. perfringens and species in the genera Streptococcus and Staphylococcus . Correlation analysis showed that the ARG number in C. perfringens strains increased with time, while the virulence gene number was relative stable. Our results, taken together with previous studies, revealed the high genome openness and genetic diversity of C. perfringens and provide a comprehensive view of the phylogeny, genomic features, virulence gene and ARG profiles of worldwide strains.

Activation-Induced cytidine Deaminase (AID) initiates affinity maturation and isotype switching by deaminating deoxycytidines within immunoglobulin genes, leading to somatic hypermutation (SHM) and class switch recombination (CSR). AID thus potentiates the humoral response to clear pathogens. Marking the 20th anniversary of the discovery of AID, we review the current understanding of AID function. We discuss AID biochemistry and how error-free forms of DNA repair are co-opted to prioritize mutagenesis over accuracy during antibody diversification. We discuss the regulation of DNA double-strand break (DSB) repair pathways during CSR. We describe genomic targeting of AID as a multilayered process involving chromatin architecture, cis- and trans-acting factors, and determining mutagenesis – distinct from AID occupancy at loci that are spared from mutation.

The information of microorganisms in aquifers can advance the understanding of the aquifer environments. Ranwu Lake is a proglacial lake located at the headwaters of Parlung Zangbo River in the Qinghai-Tibet Plateau (QTP). The information of microbial communities along the littoral gradient of Ranwu Lake can be a good indicator of water chemistry exchange between groundwater and surface water in proglacial environments. The study investigates the vertical distribution of microbial diversity and compositions in five sediment columns (two onshore, two offshore and one at the shoreline) taken from a cross section along the littoral gradient of Ranwu Lake. Along the cross section, the microbial diversity decreases toward the lake, becomes lowest in the column at the shoreline, then increases slightly in the two offshore columns. This is probably ascribed to the transition of redox conditions. Vertically, the diversity of the microbes is highest at the top and bottom of the columns. The sequencing results from the samples present 19 phyla, 38 classes, and 44 genera. Proteobacteria, Chloroflexi, and Acidobacteria are the three largest phyla. Except the offshore most column, the abundance of Proteobacteria shows a consistent pattern, while the abundance of Chloroflexi presents an inverse pattern in related to the microbial diversity. Their diversity, compositions, and abundance of microbes show a significant variation along the vertical direction and littoral gradient of the glacial lake, likely regulated by both the exchange between groundwater and surface water, and the hydrogeological properties. The variable distribution of microbial community in turn affects the physio-chemical properties of sediments and waters.

This study aimed to explore a new way to address the burning of agricultural waste in China while achieving the sustainable use of it. Three agricultural wastes (Wheat straw, peanut shell, and rice husk) were slowly pyrolyzed into biochar, which was subsequently added to the soil to reduce CO2 emissions from the soil, and to improve soil fertility as well as microbial community structure. The biochar and raw materials were added to the soil and cultured under controlled conditions, and then the CO2 emissions produced from the mixing. At the same time, this study used pot experiments to determine the effects of biochar on tobacco soil physical and chemical properties and, therefore, the microbial communities of the soil. This study suggests that (1) biochar can effectively reduce soil CO2 emission rate. Compared with the control, peanut shell biochar could reduce the total CO2 emissions of soil by 33.41%, and the total CO2 emissions of wheat straw biochar treatment was 90.25% lower than that of wheat straw treatment. (2) The soil&rsquo, s physical and chemical properties were improved. The soil bulk density of wheat straw biochar treatment kept 34.57% lower than that of the control as well as 21.15% lower than that of wheat straw treatment. The soil&rsquo, s organic carbon of peanut shell biochar treatment was 87.62% more than that of peanut shell treatment. (3) Biochar changed soil microbial community structure. (4) Biochar is suitable for tobacco growth. Peanut husk biochar significantly increased the total biomass of tobacco, and wheat straw biochar significantly increased tobacco root vigor. This study concluded that processing Chinese agricultural waste into biochar and adding it to the soil instead of burning it directly would be an effective means to reduce greenhouse gas emissions, to improve soil, and to promote crop growth.

Climate change has effects on hydrological change in multiple aspects, particularly in the headwaters of the Yellow River (HWYR), which is widely covered by climate-sensitive frozen ground. In this study, the annual runoff was partitioned into four runoff compositions: winter baseflow, snowmelt runoff, rainy season runoff, and recession flow. In addition, the effects of global warming, precipitation change, and frozen ground degradation were considered in long-term variation analyses of the runoff compositions. The moving t-test was employed to detect change points of the hydrometeorological data series from 1961 to 2013, and flow duration curves were used to analyze daily runoff regime change in different periods. It was found that the abrupt change points of cold season runoff, such as recession flow, winter baseflow, and snowmelt runoff, are different from that of the rainy season runoff. The increase in winter baseflow and decrease in snowmelt runoff at the end of 1990s was closely related to global warming. In the 21st century, winter baseflow presented a larger relative increase compared to rainy season runoff. The correlation analyses indicate that winter baseflow and snowmelt runoff are mainly controlled by water-resource-related factors, such as rainy season runoff and the accumulated precipitation in cold season. To analyze the global warming impacts, two runoff coefficients&mdash, winter baseflow discharge rate (Rw) and direct snowmelt runoff coefficients (Rs)&mdash, were proposed, and their correlation with freezing&ndash, thawing indices were analyzed. The increase of Rw is related to the increase in the air temperature thawing index (DDT), but Rs is mainly controlled by the air temperature freezing index (DDF). Meanwhile, the direct snowmelt runoff coefficient (Rs) is significantly and positively correlated to DDF and has decreased at a rate of 0.0011/year since 1980. Under global warming, the direct snowmelt runoff (runoff increment between March to May) of the HWYR could decrease continuously in the future due to the decrease of accumulative snow in cold season and frozen ground degradation. This study provides a better understanding of the long-term runoff characteristic changes in the HWYR.

Qinghai Lake plays an important role in the study of climate change in the western China and Qinghai-Tibet Plateau uplift processes and environmental effects. This study focused on the hydrogeochemistry of different waters (river, lake, groundwater, and precipitation) around and within Qinghai Lake. We analyzed major chemical elements and stable isotopes to examine water-rock interactions and the hydrogeochemical evolution of lake. The geochemical characteristics of river, groundwater, and precipitation have direct effects on the chemical composition of lake. The hydrochemical type of the river was HCO3-Ca·Na or HCO3-Na·Ca; groundwater was HCO3-Na·Ca, Cl·HCO3-Na·Ca, or HCO3-Ca·Na; and lake was Cl-Na, which was different from Erhai (Cl·HCO3-Na). The different geological settings and amount of river and groundwater input between the Buha and Shaliu subcatchments led to fluctuation in the major chemical ions present in the Buha River. The supply to river and groundwater is different in the various areas and manifests as overlap in the ion concentrations in river and groundwater. The relationship of major ions showed that sulfate reduction, ion exchange, carbonate and silicate rock weathering, dissolution, and evaporation occurred in the evolution of the groundwater, river, and lake in the Qinghai Lake catchment. The evolution of Qinghai Lake may be towards poor calcium and potassium enrichment as well as the removal of carbonate and increasing chloride. The salinity of Qinghai Lake is likely to become much higher if the amount of river and groundwater input decreases or the climate continues to dry in the future.

Understanding the vegetation phenology and its variations in the Tibetan Plateau is critical to the study of ecological responses to global climate change. In this study, several pre-processed meth...

Drawing on empirical data collected from petitioners in Chinese courts, this article analyzes how the regime’s political concern for social stability transforms petitioners’ disputes and sh...

Globally, the transportation industry is one of the leading fields that generate the largest share of greenhouse gas emissions. While undergoing rapid development, countries worldwide aim to solve the problems involved in high energy consumption. Taking China as an example, this paper studies the main factors of carbon emissions in the transport sector and analyses the decoupling states between carbon emission and economic growth, making energy efficiency policies accordingly. In order to better demonstrate the dependence of the economy on the carbon emissions in China's transportation industry comprehensively, combined with the C D production function, this paper develops the decomposition and decoupling technology based on the LMDI approach. Additionally, it quantifies seven effects: energy emission intensity effect, energy structure effect, energy intensity effect, transportation intensity effect, technology state effect, labor input effect and capital input effect. The results show three major points: (1) From 2001 to 2018, the cumulative carbon emissions of China's transportation industry increased by 633.46 million tons, in which the capital input effect is the key factor driving carbon emissions, accounting for 157.70% of the total cumulative increased emissions, followed by energy structure effect at 10.39%. The labor input effect accounted for the smallest proportion at 2.26%. In this case, the technology state effect is the primary factor in restraining carbon emissions. During the study period, it reduced carbon emissions by 292.27 million tons, accounting for 46.14%. To a certain extent, energy intensity effect, transportation intensity effect and energy emission intensity inhibited carbon emissions, representing 16.67%, 5.32% and 2.22%, respectively. (2) During the research period, two decoupling states existed between carbon emissions and economic growth in China's transportation industry, specifically weak decoupling and expansive coupling. (3) The analysis of decomposition and decoupling state of influencing factors of carbon emissions shows that, on the one hand, factors promoting carbon emissions (capital input effect, energy structure effect and labor input effect) hinder the decoupling process. On the other hand, factors restraining carbon emissions (technology state effect, transportation intensity effect, energy intensity effect and energy emission intensity effect) accelerate the decoupling process. The research findings provide a new perspective for achieving carbon emission reduction in the transportation industry and curbing energy consumption growth.

Climate warming has been driving hydrological changes across the globe, especially in high latitude and altitude regions. Long-term (1962–2012) streamflow records and permafrost data in the Yangtze River source region were selected to analyze streamflow variations and groundwater storage in response to climate warming. Results of Mann–Kendall test and Morlet wavelet analysis show that the anomalies of both annual streamflow and winter baseflow are near the year 2010, and their main period scales are 37 years and 34 years, respectively. The annual streamflow and the annual baseflow increased significantly, as assessed by the recursive digital filtering baseflow separation. Results of Pearson correlation coefficient indicate that the rising air temperature is the primary cause for the increased streamflow instead of precipitation and evaporation. By using the top temperature of permafrost model, the total permafrost area has decreased by 8200 km2 during the past 50 years, which causes groundwater storage to increase by about 1.62 km3 per year due to climate warming. More space has been made available to store the increasing meltwater during the permafrost thawing. Permafrost thawing and increasing temperature are the direct and indirect causes of the increasing groundwater storage. The results of the cumulative anomaly method and Pearson correlation coefficients show that permafrost thawing has a greater impact than increasing temperature on the increase of groundwater storage. Permafrost thawing due to climate warming show compound effects on groundwater storage–discharge mechanism, and significantly affects the mechanisms of streamflow generation and variation.

Interactions between feed size distribution and separation performance for hydrocyclones with different vortex finder diameters (Do) are crucial for hydrocyclone designs but not clearly understood. In this work, the optimum range of Do is numerically confirmed for a 50 mm diameter hydrocyclone using computational fluid dynamics. Furthermore, effects of feed size distribution (FSD) on separation performance for hydrocyclones with different Do are discussed. For a given FSD, the lower limit of Do can be determined from the flow stability characterized by lower turbulence intensity and larger tangential velocity. Below the lower limit, a large proportion of fine particles report to the underflow. The upper limit can be determined from separation performance. Above the upper limit recovery to the underflow for coarse particles decreases drastically, which is caused by an outward shift of the locus of zero vertical velocity (LZVV) and an inward shift of particles equilibrium radius. For a given Do, FSD has no significant effects on partition curves when Do is in the optimum range. When Do is above the optimum range, both recovery to underflow for coarse particles and separation sharpness are decreased as the feed median size increases. In summary, when Do is in the optimum range, the hydrocyclone can adapt to different FSD to obtain the expected cut size by self-adjusting the LZVV and particles equilibrium radius. This method for determining the optimum range of Do is based on flow pattern characteristics and can be used as a universal tool for hydrocyclone design.

Drawing from detailed courtroom discourses on divorce cases in China, this article provides a micro-level comparison between two styles of case handling: mediatory and legalistic. The two styles differ in discourse multiplicity, discourse interchange, interruption, and dispute processing. It finds that in terms of dispute resolution, the mediatory style seems to fare better than the legalistic style. One major reason for the difference is that the legalistic style tends to suppress rather than uncover what truly matters for the litigants. The mediatory style also seems to better fit the cultural expectation of suburban and rural China. The findings compel reconsideration of the extent to which rule formalism in transitional China should be promoted.

Myriophyllum aquaticum is a semi-submerged exotic macrophyte that was introduced to China for many years. This species may be found in an emergent form in aquatic environments or in an amphibious form under drained conditions. Nuisance growth of this species has often been attributed to excessive amounts of nutrients. Therefore, we tested the following hypotheses: (1) high nutrient availability facilitates the establishment of M. aquaticum and (2) fragment type interacts with nutrient availability to determine the colonization and regeneration capacities of M. aquaticum. Two types of fragments were grown in water solutions with two levels of phosphorous. After 3 weeks, the survival rates showed no significant difference between the phosphorous treatments. However, emergent fragments showed higher RGR in the low and high phosphorous treatments than amphibious fragments. In addition, emergent fragments also showed higher regeneration capacities, indicating higher invasiveness in emergent fragments compared to amphibious fragments. Moreover, the high phosphorous concentration caused emergent fragments to produce more branches, indicating that nutrient availability may increase M. aquaticum propagule pressure. Our study highlights that nutrient supply increased emergent fragment establishment and shaped the invasion dynamics of macrophytes, which could help predict the spread and potential impact of exotic macrophytes in natural aquatic ecosystems.

Pulsatile blood flow is renowned for inducing localised flow disturbances that are characterised by significant oscillations. These flow disturbances are recognised to have a physiologic significance within the cardiovascular system, particularly with respect to their proatherogenic expression on endothelial cells. Flow disturbances also impart significant influence on the mechanics of cardiovascular flow and are formally shown in the present study to be coupled to the period-average behaviour of a pulsatile flow field, causing it to be misrepresented by its steady-equivalent; which is often used in models of atherogenesis and hence limits their reliability. It is demonstrated that a measure of the localised influence of flow disturbances on the period-average flow can be realised by the relative significance of their kinetic energy, which is quantified by the introduced Oscillatory Kinetic Energy Index (OKEI). A specific measure of direction-reversing oscillations is also developed with the introduction of the Oscillatory Flow Index (OFI), which is an extension of the wall-bound Oscillatory Shear Index (OSI) onto flow and wall spaces. A case study of a human carotid artery is made; wherein pulsatile flow is studied relative to its steady-equivalent state. The introduced indices are demonstrated to collectively identify oscillatory flow disturbances within the flow; quantifying their spatial distribution and influence on the flow field.

Existing design equations can hardly provide reliable guidance in hydrocyclone designs and give explanations for the selected optimum range. Therefore, a new method combined flow patterns and equation models (FP-EM) for hydrocyclone designs is proposed in this paper. The feed flow rate is used as a parameter to evaluate the FP-EM method. Results show that under a lower feed flow rate, the inner flow field is extremely unsteady, which is characterized by higher turbulence intensity and an unsteady air core. When the flowrate becomes extremely large, the value of the exponent n for the tangential velocity inside the free vortex region decreases. Furthermore, before flow field achieving stability, the separation accuracy is extremely low. In the optimum range, the separation efficiency and the accuracy increases with the increase of the feed flow rate, while the cut size decreases. Thus, for the φ50 mm hydrocyclone used in this study, the lower limit (15 L/min) can be determined by the flow field stability and the upper limit (55 L/min) is largely ascertained by energy consumption. Three power-type fitting equations are deduced in the optimum range to quantify the relationships between separation indexes (split ratio, pressure drop and cut size) and the flowrate. Correlation coefficients ( R 2 > 0.97) of three equations verify that equation models can predict the separation performance successfully. Therefore, all above results confirm that the FP-EM method is capable of providing an optimum range, quantifying the relationships between separation indexes and the feed parameter, and predicting separation performances.

Linalool and geraniol are the primary components of rose oil, palmarosa oil, and citronella oil and many other essential oils, and two important compounds used in the flavour and fragrance, cosmetic or pharmaceutical industries. Phase equilibria (LLE, VLE, solubility, etc.) and related thermodynamic properties of a mixture are essential in the processes design and control of mass transfer process. In this work, experimental (liquid + liquid) equilibria data of the systems (water + 1-propanl + linalool) and (water + 1-propanl + geraniol) are presented. The (liquid + liquid) equilibria of both systems were determined with a tie-line method at T = (283.15, 298.15 and 313.15) K under atmospheric pressure. The well-known Hand, Bachman and Othmer–Tobias equations were used to test the reliability of the experimental values. The influence of the temperature on the (liquid + liquid) phase equilibria of the mixtures, the binodal curves and distribution ratios of 1-propanl are shown and discussed. Moreover, the NRTL and UNIQUAC models were applied to fit the data for both ternary systems. The interaction parameters obtained from both models successfully correlated the equilibrium compositions. Furthermore, the ternary systems could be represented using the binary parameters of the thermodynamic model with a function of temperature.

As an eco-friendly compound and good solvent, cineole (1,8-cineole, eucalyptol) has been evaluated for the extraction property of phenols (phenol or p-cresol) from aqueous solutions. This paper presents experimental (liquid + liquid) equilibrium (LLE) data for the ternary (water + phenol + cineole) and (water + p-cresol + cineole) mixtures from high concentration to low concentration of phenols-water solution. The mutual solubility of the binary (water + cineole) and (water + phenol or p-cresol) systems, and the LLE results for the ternary systems were determined with a tie-line method at T = (283.15, 298.15, and 313.15) K under atmospheric pressure. The experiment LLE results showed that cineole as a good extractant exhibited high extraction ability for phenol or p-cresol from aqueous solutions. The influence of temperature on the (liquid + liquid) phase equilibria was studied. The well-known Hand and Bachman equations were used to test the reliability of the experimental values. Moreover, the experimental LLE results were satisfactorily correlated by the NRTL and UNIQUAC models.

A sophisticated computational model of metal inert gas arc welding of aluminium alloys is presented. The arc plasma, the wire electrode and the workpiece are included in the computational domain self-consistently. The flow in the arc plasma and in the weld pool are calculated in three dimensions using equations of computational fluid dynamics, modified to take into account plasma effects and coupled to electromagnetic equations. The formation of metal vapour from the wire electrode and workpiece is considered, as is the mixing of the wire electrode alloy with the workpiece alloy in the weld pool. A graphical user interface (GUI) has been developed, and the model runs on standard desktop or laptop computers. The computational model is described, and results are presented for lap-fillet weld geometry. The importance of including the arc in the computational domain is shown. The predictions of the model show good agreement with measurements of weld geometry and weld composition. The GUI is introduced, and the application of the model to predicting the thermal history of the workpiece, which is the input information that is required for predicting important weld properties such as residual stress and distortion and weld microstructure, is discussed. Initial predictions of residual stress and distortion of the workpiece are presented.

The aim of this study was to determine the presence and characteristics of Escherichia coli in ready-to-eat (RTE) foods. A total of 300 RTE foods samples were collected in Shaanxi Province, People's Republic of China: 50 samples of cooked meat, 165 samples of vegetable salad, 50 samples of cold noodles, and 35 samples of salted boiled peanuts. All samples were collected during summer (in July to October) 2011 and 2012 and surveyed for the presence of E. coli. E. coli isolates recovered were classified by phylogenetic typing using a PCR assay. The presence of Shiga toxin genes 1 (stx1) and 2 (stx2) was determined for these E. coli isolates by PCR, and all isolates were analyzed for antimicrobial susceptibility and the presence of class 1 integrons. Overall, 267 (89.0%) RTE food samples were positive for E. coli: 49 cold noodle, 46 cooked meat, 150 salad vegetable, and 22 salted boiled peanut samples. Of the 267 E. coli isolates, 73.0% belong to phylogenetic group A, 12.4% to group B1, 6.4% to grou...

APOBEC3G (A3G), an enzyme expressed in primates with the potential to inhibit human immunodeficiency virus type 1 (HIV-1) infectivity, is a single-stranded DNA (ssDNA) deoxycytidine deaminase with two domains, a catalytically active, weakly ssDNA binding C-terminal domain (CTD) and a catalytically inactive, strongly ssDNA binding N-terminal domain (NTD). Using optical tweezers, we measure A3G binding a single, long ssDNA substrate under various applied forces to characterize the binding interaction. A3G binds ssDNA in multiple steps and in two distinct conformations, distinguished by degree of ssDNA contraction. A3G stabilizes formation of ssDNA loops, an ability inhibited by A3G oligomerization. Our data suggests A3G securely binds ssDNA through the NTD, while the CTD samples and potentially deaminates the substrate. Oligomerization of A3G stabilizes ssDNA binding but inhibits the CTD’s search function. These processes explain A3G’s ability to efficiently deaminate numerous sites across a 10,000 base viral genome during the reverse transcription process.

Forecasting short-term traffic flow is a key issue in the field of Intelligent Traffic System (ITS). Most of the existing researches are oriented to urban road network, the development of urban traffic flow forecasting technology provides a good reference for traffic flow forecasting in the port. However, the complexity and uncertainty of port traffic determine that it is necessary to study the forecasting methods of port traffic flow pertinently. Based on the K- Nearest Neighbor (KNN) algorithm, this paper forecasted short-term traffic flow, and defined the factors affecting short-term traffic flow in the port, such as port working status and operation instruction characteristics, as state vector, and used K-Dimension Tree (KD tree) to reduce the time complexity of neighbor searching. One-month traffic flow data of an inland port in Chongqing was selected to verify the prediction algorithm. Firstly, the number of neighbors was identified, and 8 was the best, then the prediction accuracy was verified to meet the usage requirements, which could provide reference for scientific planning and management of port traffic.

Based on the analysis of the existing knowledge base question answering (KBQA) system, it is found that the open domain KBQA in Chinese lacks support for multi-relational question answering (MRQA). Based on the knowledge base (KB) provided by NLPCC-ICCPOL 2016, MRQA in Chinese domain is explored in this paper. The KBQA process is divided into three steps: entity recognition, entity relation extraction and answer retrieval. Entity recognition is the focus of this paper. A deep leaning model is introduced to identify multiple entities in the question, and the method of similarity calculation is used to link and disambiguate the identified entities with terms in the KB. The experimental results show that the method can support MRQA with a higher average F1 score.

Bifidobacterium and Lactobacillus are beneficial for human health, and many strains of these two genera are widely used as probiotics. We used two large datasets published by the American Gut Project (AGP) and a gut metagenomic dataset (NBT) to analyze the relationship between these two genera and the community structure of the gut microbiota. The meta‐analysis showed that Bifidobacterium, but not Lactobacillus, is among the dominant genera in the human gut microbiota. The relative abundance of Bifidobacterium was elevated when Lactobacillus was present. Moreover, these two genera showed a positive correlation with some butyrate producers among the dominant genera, and both were associated with alpha diversity, beta diversity, and the robustness of the gut microbiota. Additionally, samples harboring Bifidobacterium present but no Lactobacillus showed higher alpha diversity and were more robust than those only carrying Lactobacillus. Further comparisons with other genera validated the important role of Bifidobacterium in the gut microbiota robustness. Multivariate analysis of 11,744 samples from the AGP dataset suggested Bifidobacterium to be associated with demographic features, lifestyle, and disease. In summary, Bifidobacterium members, which are promoted by dairy and whole‐grain consumption, are more important than Lactobacillus in maintaining the diversity and robustness of the gut microbiota., Our study has shown that Bifidobacterium, as a dominant genus, played an important role in terms of the diversity and stability of gut microbiota examined using American Gut Project. It is more helpful to increase the alpha diversity and the stability of gut microbiota than Lactobacillus. Furthermore, we found that whole‐grain consumption and fruit consumption could increase the abundance of Bifidobacterium.