Effect of Modified Cellulose Nanocrystals on the Structure of Calcium Silicate Hydrate Studied by Molecular Dynamics Simulation and Experiment.

The interfacial bonding of the four cellulose nanocrystals (CNCs) and calcium silicate hydrate (C-S-H) in vacuum and solution conditions was analyzed by molecular dynamics simulation. The binding energies were calculated, and the sources of interface strength were analyzed by the formation and lifetime of hydrogen bonds. The adsorption between CNC/C-S-H was characterized by the movement of interfacial atoms and CNC's adsorption conformation. The types of the functional group determine the bonding of the CNC/C-S-H, and the interface adsorption in two simulation conditions both followed: CNC-C (carboxyl) > CNC-O (hydroxyl) > CNC-N (amino) > CNC-S (sulfonic). The bonding of the interface affects the load transferred between the matrix and CNC, which can be reflected in the overall mechanical properties of the mortar. The mechanical strength of the mortar is in line with the simulation results. CNC-C has the strongest reinforcement effect, while CNC-S has the weakness effect. In the solution simulation, there is almost no chemical adsorption between C-S-H and CNC-S; instead, CNC-S decreased the bonding between the matrix and reduced the strength of the sample. Scanning electron microscopy found that CNC was interspersed in the matrix, riveting the matrix and enhanced the stability of the mortar structure. The influence of CNC on the mortar structure was analyzed by the calcium to silicon ratio (C/S) and it was showed that CNC-C, CNC-O, and CNC-N have an enhancement effect, while CNC-S decreased the coherence of the cement matrix. Durability and nuclear magnetic resonance tests further verified the effect of the four CNCs on the structure of mortar, and results indicated that CNC-C, CNC-O, and CNC-N can control the growth of hydration crystals, fill the cracks, and reduced porosity of samples, while CNC-S reduces the compactness of hydration products and ultimately decreased the mechanical and durability properties of the mortar.

Multi-F-Structured MOF Materials Enhance Nanogenerator Output Performance for Corrosion Protection of Metallic Materials.

MOF (metal organic framework) materials have been used as functional materials in a number of fields due to their diverse spatial tunability, which produces rich porous structures with stable and continuous pores and a high specific surface area. A triboelectric nanogenerator can convert trace mechanical energy into electrical energy, and the application of MOF materials to triboelectric nanogenerators has been intensively studied. In this work, we report on two MOFs with similar spatial structures, and the modulation of the end microstructures was achieved using the difference in F content. The output performance of friction power generation increases with the increase in F content, and the obtained polyacidic ligand materials can be used to construct self-powered corrosion protection systems, which can effectively protect metallic materials from corrosion.

Assessment of vegetation change on the Mongolian Plateau over three decades using different remote sensing products.

As a major component of temperate steppes in the Eurasian continent, the Mongolian Plateau (MP) plays a pivotal role in the East Asian and global carbon cycles. This paper describes the use of five remote sensing indices derived from satellite data to characterize vegetation cover on MP, namely: gross primary production (GPP), net primary production (NPP), normalized difference vegetation index (NDVI), leaf area index (LAI) and fractional vegetation cover (FVC). It is found that GPP, NPP, and NDVI exhibit increasing trends, whereas LAI and FVC present decreasing trends on the MP since 1982. The different indices highlight discrepancies in the spatial pattern of vegetation growth, with the greatest increase in the southeast of MP. Only 3.4% of the total land area of MP exhibited consistent trends in the indices (0.1% degradation and 3.3% growth, P < 0.01), with the synchronous change of both LAI and NPP exhibiting higher consistency than that of raw NDVI and NPP. Understanding of the characteristics and status of vegetation change on the MP has far-reaching implications for its ecological protection management, and climate change mitigation.

LncRNA FTX Promotes Colorectal Cancer Cells Migration and Invasion by miRNA-590-5p/RBPJ Axis.

Colorectal cancer (CRC) is one of the most lethal human cancers all over the world. Moreover, it ranks fourth for cancer-related deaths among males. Although many efforts have been made to cure CRC, the effect remains limited. It has been reported that lncRNA five prime to Xist (FTX) was upregulated in CRC. However, the mechanism by which lncRNA FTX regulates the progression of CRC remains largely unknown. In this study, qRT-PCR was performed to detect the expression of FTX, miR-590-5p and Recombination signal binding protein for immunoglobulin kappa J region (RBPJ) in CRC tissues or cells. Protein expression in cells was measured by western blot. MTT assay was used to test the cell viability. Moreover, transwell was performed to examine the cell migration and invasion. Luciferase report assay was performed to verify the relation between miR-590-5p and FTX or RBPJ. It was found that FTX was upregulated in CRC tissues and cells. Knockdown of FTX or overexpression of miR-590-5p can inhibit the proliferation, migration, and invasion of CRC cells. Besides, silencing of FTX could inhibit the expression of migration and invasion-related proteins in CRC cells. Meanwhile, miR-590-5p was the target of FTX, and RBPJ was the direct target of miR-590-5p. Inhibition of miR-590-5p could reverse the inhibitory effect of FTX on the progression of CRC. These findings suggested that knockdown of FTX could inhibit the tumorigenesis of CRC in vitro, which may serve as a potential novel strategy for treatment of CRC.

Rab5a Promotes Cytolethal Distending Toxin B-Induced Cytotoxicity and Inflammation.

The cytolethal distending toxin B subunit (CdtB) induces significant cytotoxicity and inflammation in many cell types that are involved in the pathogenesis of postinfectious irritable bowel syndrome (PI-IBS). However, the underlying mechanisms remain unclear. This study tested the potential role of Rab small GTPase 5a (Rab5a) in the process. We tested mRNA and protein expression of proinflammatory cytokines (interleukin-1ß [IL-1ß] and IL-6) in THP-1 macrophages by quantitative PCR (qPCR) and enzyme-linked immunosorbent assays (ELISAs), respectively. In the primary colonic epithelial cells, Cdt treatment induced a CdtB-Rab5a-cellugyrin association. Rab5a silencing, by target small hairpin RNAs (shRNAs), largely inhibited CdtB-induced cytotoxicity and apoptosis in colon epithelial cells. CRISPR/Cas9-mediated Rab5a knockout also attenuated CdtB-induced colon epithelial cell death. Conversely, forced overexpression of Rab5a intensified CdtB-induced cytotoxicity. In THP-1 human macrophages, Rab5a shRNA or knockout significantly inhibited CdtB-induced mRNA expression and production of proinflammatory cytokines (IL-1ß and IL-6). Rab5a depletion inhibited activation of nuclear factor-κB (NF-κB) and Jun N-terminal protein kinase (JNK) signaling in CdtB-treated THP-1 macrophages. Rab5a appears essential for CdtB-induced cytotoxicity in colonic epithelial cells and proinflammatory responses in THP-1 macrophages.

Transcriptomic analysis of Bursaphelenchus xylophilus treated by a potential phytonematicide, punicalagin.

Punicalagin showed significant nematotoxic activity against pine wood nematode (PWN), Bursaphelenchus xylophilus, in the authors' previous research. The authors performed high-throughput transcriptomic sequencing of punicalagin-treated nematodes to generate clues for its nematotoxic mechanism of action. The authors identified 2,575 differentially expressed genes, 1,428 of which were up-regulated and 1,147 down-regulated. Based on a comprehensive functional in silico analysis, the authors speculate that PWN may respond to the stimulus of punicalagin through phagosome, endocytosis, peroxisome and MAPK signaling pathways. In addition, punicalagin could greatly affect PWN energy metabolism including oxidative phosphorylation. The genes encoding twitchin and a nematode cuticular collagen could be crucial regulation targets of punicalagin, which might contribute to its nematotoxic activity against PWN.Punicalagin showed significant nematotoxic activity against pine wood nematode (PWN), Bursaphelenchus xylophilus, in the authors' previous research. The authors performed high-throughput transcriptomic sequencing of punicalagin-treated nematodes to generate clues for its nematotoxic mechanism of action. The authors identified 2,575 differentially expressed genes, 1,428 of which were up-regulated and 1,147 down-regulated. Based on a comprehensive functional in silico analysis, the authors speculate that PWN may respond to the stimulus of punicalagin through phagosome, endocytosis, peroxisome and MAPK signaling pathways. In addition, punicalagin could greatly affect PWN energy metabolism including oxidative phosphorylation. The genes encoding twitchin and a nematode cuticular collagen could be crucial regulation targets of punicalagin, which might contribute to its nematotoxic activity against PWN.

SP1-mediated overexpression of lncRNA LINC01234 as a ceRNA facilitates non-small-cell lung cancer progression via regulating OTUB1.

Long noncoding RNAs (lncRNAs) have been confirmed to be strongly associated with the progression of various types of cancer. LncRNA LINC01234 (LINC01234) is a newly identified tumor-related lncRNA whose upregulation has been confirmed in some tumors. However, its potential expressions and possible functions in non-small-cell lung cancer (NSCLC) have not been explored. In this study, we first found that LINC01234 expressions were distinctly upregulated in both NSCLC samples and cell lines using RT-PCR. Our group also showed that LINC01234 upregulations were modulated by nuclear transcription factor SP1. The results form clinical investigations indicated that high LINC01234 expressions were associated with positively lymph node metastasis and advanced tumor-metastasis-node (TMN) stage. Kaplan-Meier assays indicated that patients with NSCLC having high LINC01234 expressions tend to have unfavorable clinical prognosis. Using multivariate assays, it was confirmed that LINC01234 was an independent prognostic factor for patients with NSCLC. In vitro assays showed that inhibition of LINC01234 suppressed NSCLC cell proliferation, cell colony formation and metastasis, and greatly promoted apoptosis. Mechanistic investigations revealed LINC01234 promotes the progression of NSCLC cells by the modulation of miR-140 to positively regulate OTUB1 expression. Taken together our findings, they provided an exhaustive assay of LINC01234 in NSCLC and imperative clues for insights into the potential effects of lncRNAs-miRNAs regulatory network in NSCLC.

Plasmapheresis Combined with Continuous Plasma Filtration Adsorption Rescues Severe Acute Liver Failure in Wilson's Disease before Liver Transplantation.

Wilsonian crisis (hemolytic crisis and acute liver failure [ALF] in Wilson's disease) is fatal and almost all patients ultimately need a timely liver transplantation to save their lives. How to safely pass the critical period to liver transplantation is still a big challenge to doctors especially to pediatricians facing more difficult situations in blood purification. Here, we report about a 7-year-old child (weight 21 kg) presenting with severe hemolysis and impending ALF that made a rapid recovery with prompt initiation of plasmapheresis combined with continuous plasma filtration adsorption (CPFA) and chelation therapy. Rapidly efficient removal of copper, bilirubin, and albumin-binding toxins by hybrid blood purification alleviated hemolysis and liver injury and successfully bridged the patient over the critical period to late liver transplantation. Moreover, a review of the literature was performed examining the use of plasmapheresis, molecular adsorbent recirculation system, single-pass albumin dialysis, and continuous veno-venous hemodiafiltration in Wilson disease. The experience of our case points to that plasmapheresis combined with CPFA treatment can improve clinical symptoms and bridge children over through Wilsonian crisis to late live transplantation, and CPFA treatment is feasible and safe in children weighing more than 20 kg.

A pilot study of radiomics technology based on X-ray mammography in patients with triple-negative breast cancer.

PURPOSE: To explore the radiomics features of triple negative breast cancer (TNBC) and non-triple negative breast cancer (non-TNBC) based on X-ray mammography, and to differentiate the two groups of cases. MATERIALS AND METHODS: Preoperative mammograms of 120 patients with breast ductal carcinoma confirmed by surgical pathology were retrospectively analyzed, which include 30 TNBC and 90 non-TNBC patients. The manual segmentation of breast lesions was performed by ITK-SNAP software and 12 radiomics features were extracted by Omni-Kinetics software. The differences of these radiomics features between TNBC and non-TNBC groups were compared, and the receiver operating characteristic (ROC) curve was used to determine the optimal cutoff value of each radiomics parameter for differentiating TNBC from non-TNBC, and the corresponding area under the curve (AUC), sensitivity and specificity were obtained. RESULTS: There were statistically significant differences for 4 radiomics features between TNBC and non-TNBC datasets (P < 0.05). They were the roundness, concavity, gray average and skewness of breast lesions. Compared with non-TNBC, TNBC cases have following characteristics of (1) more round with the roundness of 0.621 vs. 0.413 (P < 0.001), (2) more regular with the concavity of 0.087 vs. 0.141 (P < 0.01), (3) higher density or gray average (67.261 vs. 56.842, P < 0.05), and (4) lower skewness (- 0.837 vs.- 0.671, P = 0.034). AUCs of ROC curves computed using features of the roundness and concavity were both larger than 0.70. CONCLUSION: Radiomics features based on X-ray mammography may be helpful to distinguish between TNBC and non-TNBC, which were associated with breast tumor histology.

Projected Temperature-Related Years of Life Lost From Stroke Due To Global Warming in a Temperate Climate City, Asia: Disease Burden Caused by Future Climate Change.

BACKGROUND AND PURPOSE: Global warming has attracted worldwide attention. Numerous studies have indicated that stroke is associated with temperature; however, few studies are available on the projections of the burden of stroke attributable to future climate change. We aimed to investigate the future trends of stroke years of life lost (YLL) associated with global warming. METHODS: We collected death records to examine YLL in Tianjin, China, from 2006 to 2011. We fitted a standard time-series Poisson regression model after controlling for trends, day of the week, relative humidity, and air pollution. We estimated temperature-YLL associations with a distributed lag nonlinear model. These models were then applied to the local climate projections to estimate temperature-related YLL in the 2050s and 2070s. We projected temperature-related YLL from stroke in Tianjin under 19 global-scale climate models and 3 different greenhouse gas emission scenarios. RESULTS: The results showed a slight decrease in YLL with percent decreases of 0.85%, 0.97%, and 1.02% in the 2050s and 0.94%, 1.02%, and 0.91% in the 2070s for the 3 scenarios, respectively. The increases in heat-related annual YLL and the decreases in cold-related YLL under the high emission scenario were the strongest. The monthly analysis showed that the most significant increase occurred in the summer months, particularly in August, with percent changes >150% in the 2050s and up to 300% in the 2070s. CONCLUSIONS: Future changes in climate are likely to lead to an increase in heat-related YLL, and this increase will not be offset by adaptation under both medium emission and high emission scenarios. Health protections from hot weather will become increasingly necessary, and measures to reduce cold effects will also remain important.

Shifts in the dynamics of productivity signal ecosystem state transitions at the biome-scale.

Understanding ecosystem dynamics and predicting directional changes in ecosystem in response to global changes are ongoing challenges in ecology. Here we present a framework that links productivity dynamics and ecosystem state transitions based on a spatially continuous dataset of aboveground net primary productivity (ANPP) from the temperate grassland of China. Across a regional precipitation gradient, we quantified spatial patterns in ANPP dynamics (variability, asymmetry and sensitivity to rainfall) and related these to transitions from desert to semi-arid to mesic steppe. We show that these three indices of ANPP dynamics displayed distinct spatial patterns, with peaks signalling transitions between grassland types. Thus, monitoring shifts in ANPP dynamics has the potential for predicting ecosystem state transitions in the future. Current ecosystem models fail to capture these dynamics, highlighting the need to incorporate more nuanced ecological controls of productivity in models to forecast future ecosystem shifts.

A Time-Series Study of the Effect of Air Pollution on Outpatient Visits for Acne Vulgaris in Beijing.

BACKGROUND/AIMS: There is increasing evidence that exposure to air pollutants, including particulate matter (PM2.5, PM10), nitrogen dioxide (NO2), and sulfur dioxide (SO2), might aggravate preexisting skin diseases such as eczema and urticaria. Here we investigated if a possible link exists between air pollution and acne vulgaris. We assessed the association between ambient air pollutant concentrations and the number of visits of patients for acne vulgaris to a dermatological outpatient clinic in Beijing, China, from April 1, 2012 to April 30, 2014. METHODS: In this time period, 59,325 outpatient visits were recorded because of acne vulgaris. Daily air pollution parameters for PM10, PM2.5, SO2, and NO2 were obtained from the Beijing Municipal Environmental Monitoring Center. RESULTS: Increased concentrations of ambient PM2.5, PM10, and NO2 were significantly associated with increased numbers of outpatient visits for acne vulgaris over the 2 years. These effects could be observed for NO2 in a single-pollutant model and for PM2.5, PM10, and NO2 in 2-pollutant models, which are closer to real-life exposure. Of note, these effects were specific because they were not observed for increased SO2 concentrations, which even showed negative correlations in all test models. CONCLUSION: This study provides indirect evidence for a link between acne vulgaris and air pollution.

Effects of betaine supplementation on L-threonine fed-batch fermentation by Escherichia coli.

Betaine can act as a stress protectant, methyl donor, or enzyme stabilizer in vitro for the biosynthesis of structurally complex compounds. The performances of betaine type and concentration on the metabolic processes of Escherichia coli JLTHR in a 5-L fermentor were investigated. The results showed that the maximum L-threonine production of 127.3 g/L and glucose conversion percentage of 58.12% was obtained fed with the glucose solution containing 2 g/L betaine hydrochloride, which increased by 14.5 and 6.87% more compared to that of the control, respectively. This study presents an analysis of the metabolic fluxes of E. coli JLTHR for the production of L-threonine with betaine supplementation. When betaine was fed into the fermentation culture medium, the metabolic flux entering into the pentose phosphate pathway (HMP) and biosynthesis route of L-threonine increased by 57.3 and 10.1%, respectively. In conclusion, exogenous addition of betaine was validated to be a feasible and efficacious approach to improve L-threonine production.

Nematotoxic coumarins from Angelica pubescens Maxim. f. biserrata Shan et Yuan roots and their physiological effects on Bursaphelenchus xylophilus.

The ethanol extracts from the roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan was toxic against the pine wood nematode Bursaphelenchus xylophilus. The ethyl acetate-soluble fraction derived from this extract increased its potency with a mortality of 95.25% in 72 hr at 1.0 mg/mL. Four nematotoxic coumarins were obtained from the ethyl acetate extract by bioassay-guided isolation. These were identified as osthole 1, columbianadin 2, bergapten 3 and xanthotoxin 4 by mass and nuclear magnetic resonance spectral data analysis. The LC50 values against B. xylophilus in 72 hr were 489.17, 406.74, 430.08, and 435.66 µM, respectively. These compounds also altered the smooth morphology of the B. xylophilus exoskeleton to a rough and pitted appearance as visualized by electron microscopy. The coumarins 1-4 possessed significant acetylcholinesterase inhibitory activities but had negligible effects on amylase and cellulase. This research provides additional clues to the nematotoxic mechanism of coumarins against the pine wood nematode B. xylophilus. This work will assist in the development of coumarin nematicides with enhanced activity using molecular modifications of the core coumarin structure.The ethanol extracts from the roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan was toxic against the pine wood nematode Bursaphelenchus xylophilus. The ethyl acetate-soluble fraction derived from this extract increased its potency with a mortality of 95.25% in 72 hr at 1.0 mg/mL. Four nematotoxic coumarins were obtained from the ethyl acetate extract by bioassay-guided isolation. These were identified as osthole 1, columbianadin 2, bergapten 3 and xanthotoxin 4 by mass and nuclear magnetic resonance spectral data analysis. The LC50 values against B. xylophilus in 72 hr were 489.17, 406.74, 430.08, and 435.66 µM, respectively. These compounds also altered the smooth morphology of the B. xylophilus exoskeleton to a rough and pitted appearance as visualized by electron microscopy. The coumarins 1-4 possessed significant acetylcholinesterase inhibitory activities but had negligible effects on amylase and cellulase. This research provides additional clues to the nematotoxic mechanism of coumarins against the pine wood nematode B. xylophilus. This work will assist in the development of coumarin nematicides with enhanced activity using molecular modifications of the core coumarin structure.

An application study of low-dose computed tomography perfusion imaging (LDCTPI) in breast cancer and breast fibroadenoma.

PURPOSE: To explore the characteristics of breast cancer and breast fibroadenoma using low-dose computed tomography perfusion imaging (LDCTPI) including specific perfusion parameter values, and seek the potential clinical applications in cancer prognosis assessment. MATERIALS AND METHODS: Fifty patients including 30 diagnosed with breast cancer and 20 with breast fibroadenoma, as well as 15 control subjects with normal breasts were studied prospectively using LDCTPI examinations. The acquired volumetric imaging data were used for calculation, mapping and analysis by using a body tumor perfusion protocol in the CT perfusion software to measure 4 parameters: blood flow (BF), blood volume (BV), mean transit time (MTT), and the permeability surface (PS) area product. Statistical data analysis was then performed to distinguish the difference of the 4 parameter values among normal control, breast cancer and breast fibroadenoma cases. RESULTS: The mean perfusion values of 15 normal controls were as follows: BF, 20.03±4.08 mL/100 g/min; BV, 4.53±0.95 mL/100 g; MTT, 5.90±0.82 s; and PS, 9.25±1.18 mL/100 g/min. The mean perfusion values of 30 cancer patients were as follows: BF, 56.67±6.59 mL/100 g/min; BV, 5.82±0.68 mL/100 g; MTT, 6.01±0.82 s; and PS, 24.95±5.05 mL/100 g/min. The mean perfusion values of 20 patients with breast fibroadenoma were as follows: BF, 46.24±6.65 mL/100 g/min; BV, 5.07±0.73 mL/100 g; MTT, 7.51±0.62 s; and PS, 16.73±6.48 mL/100 g/min. Comparing the 3 groups, differences were all statistically significant for BF, BV, MTT and PS values (p < 0.05, respectively); The BF, BV, PS values were highest in group of cancer patients, while the MTT value was highest in group of patients diagnosed with breast fibroadenoma. CONCLUSION: Breast CT perfusion imaging is a promising functional imaging technology in breast cancer diagnosis, which can provide valuable quantitative imaging markers to assist evaluation of breast tumors.

A synthesis of the effect of grazing exclusion on carbon dynamics in grasslands in China.

Grazing exclusion (GE) is considered to be an effective approach to restore degraded grasslands and to improve their carbon (C) sequestration. However, the C dynamics and related controlling factors in grasslands with GE have not been well characterized. This synthesis examines the dynamics of soil C content and vegetation biomass with the recovery age through synthesizing results of 51 sites in grasslands in China. The results illustrate increases in soil C content and vegetation biomass with GE at most sites. Generally, both soil C content and vegetation biomass arrive at steady state after 15 years of GE. In comparison, the rates of increase in above- and belowground biomass declined exponentially with the age of GE, whereas soil C content declined in a milder (linear) way, implying a lagged response of soil C to the inputs from plant biomass. Mean annual precipitation (MAP) and the rate of soil nitrogen (N) change were the main factors affecting the rate of soil C content change. MAP played a major role at the early stage, whereas the rate of soil N change was the major contributor at the middle and late stages. Our results imply that the national grassland restoration projects in China may be more beneficial for C sequestration in humid regions with high MAP. In addition, increased soil N supply to grasslands with GE at the latter recovery stage may enhance ecosystem C sequestration capacity.

Short-term exposure to air pollution and morbidity of COPD and asthma in East Asian area: A systematic review and meta-analysis.

BACKGROUND: The association between short-term exposure to air pollution and morbidity of COPD and asthma has been observed in many studies. However, there is a lack of systematic review of the overall risk ratios in East Asian area to provide scientific evidence for health risk assessment. METHODS: A systematic literature retrieval was conducted in December 2014. The results from eligible studies were stratified by pollutants, diseases, types of hospital utilization, and age groups of the subject. For each pollutant-outcome pair, meta-analysis was conducted to calculate the pooled risk ratios (RR) with 95% confidence intervals for every 10µg/m(3) increase in pollutants (1mg/m(3) in CO). We also performed meta-regression to explore the source of heterogeneity and funnel plots to detect publication bias. RESULTS: Based on results from 26 studies, statistically significant pooled RRs of different pollutants and age groups ranged from 1.007 (SO2 in all ages) to 1.028 (O3 in all ages) for COPD general hospital admissions, 1.011 (SO2 in all ages) to 1.028 (O3 in all ages) for COPD emergency hospital admissions, 1.013 (PM10 in all ages) to 1.141 (CO in children) for all-type asthma hospital utilization, 1.010 (PM10 in all ages) to 1.141 (CO in children) for asthma general hospital admissions, and 1.009 (SO2 in all ages) to 1.040 (NO2 in children) for asthma emergency hospital admissions. The association between air pollution and asthma morbidity was generally stronger in children, but not significant in people aged 15-64. CONCLUSIONS: Evidence was found that short-term exposure to air pollution was associated with increasing risk of hospital utilization for COPD and asthma in the whole population, the elderly and children, but not in people aged 15-64. Children tended to be more susceptible to the effect of air pollution on asthma morbidity.

[Study of relationship between atmospheric fine particulate matter concentration and one grade a tertiary hospital emergency room visits during 2012 and 2013 in Beijing].

OBJECTIVE: To explore the concentration-response relationship between ambient concentration of PM2.5 and daily total hospital emergency room visits in Beijing during 2012 and 2013. This study also examined the effects of ambient PM2.5 during heavy polluted days on emergency room visits compared with the light polluted days. METHODS: We collected the daily meteorological factors monitoring data and concentrations of air pollutants in Beijing during October 1, 2012 to December 31, 2013. We also collected the daily emergency room visits from a tertiary hospital in Beijing in the same time period. Generalized additive model was fitted to estimate the association between the ambient PM2.5 and the hospital emergency room visits, by using the smooth function to adjust long term trend of time, public holidays and day of week. In addition, constrained piecewise linear function was then used to estimate the excess risk for different segment of concentration-response function. RESULTS: The annual average concentration of PM2.5 was 90.9 µg/m(3) during October 1, 2012 and December 31, 2013. There were total 64 260 cases for total emergency room visits, of which respiratory disease had 9 849 cases and cardiovascular disease had 11 168 cases. PM2.5 was positive related with PM10, NO2 and SO2. The corresponding correlation coefficients were 0.87, 0.78 and 0.62, respectively (P<0.05). And PM2.5 was positively related with relative humidity, with correlation coefficient 0.45 (P<0.05). But PM2.5 was negatively related with mean temperature (r=-0.17, P< 0.05) and wind speed (- 0.32, P<0.05). In the single polluted model, after adjusting the effects of temperature, relative humidity and wind, every 10 µg/m(3) increase of concentration of ambient PM2.5, the corresponding excess risk of daily emergency room visits was 0.25% (95% CI: 0.07-0.43). In the two-pollutant model PM2.5+SO2 and PM2.5+NO2, every 10 µg/m(3) increase of concentration of ambient PM2.5, the corresponding excess risk of daily emergency room visits were 1.07% (95%CI:0.83-1.30) and 0.56% (95%CI: 0.32-0.80) respectively, which were higher than the effect in single pollutant model. Average concentration of ambient particulate matters (PM2.5) was 204.16 µg/m(3) during heavy pollution, higher than control period (85.24 µg/m(3)). When PM2.5 as the primary air pollutants during heavy polluted days, we observed a significant increase in emergency room visits, and the odd ratios was 1.16 (95% CI:1.09-1.22). CONCLUSION: There were positive correlation between high concentration of ambient particulate matters (PM2.5) and increasing daily emergency room visits. Especially during the heavy polluted days, the effects of elevated concentration of PM2.5 on hospital emergency room visits were much larger.

Organocatalyzed asymmetric aldol reactions of ketones and ß,γ-unsaturated α-ketoesters and phenylglyoxal hydrates.

Enantioselective aldol reactions of acetophenone with ß,γ-unsaturated α-ketoesters and cyclic ketones with phenylglyoxal hydrates were realized with cinchona alkaloid-derived thiourea catalysts. The corresponding aldol products were obtained in high yields and good to excellent diastereoselectivities and enantioselectivities (up to 95% ee).

A neuron model with nonlinear membranes.

One-layer membrane separates the gradient field in and out of the cell, while some two-layer membranes filled with excitable media/material are important to regulate the energy flow when ions are propagated and diffused. The intracellular and extracellular media can be effectively separated by the membrane. It is important to clarify and describe the biophysical function and then the capacitive property can be reproduced in equivalent neural circuit. Here, we suggest the cell membrane has certain thickness and becomes flexible under external stimuli, therefore, it is considered as a kind of nonlinear media. To mimic the physical property of the two-layer cell membrane, a nonlinear resistor is used to connect two linear circuits, which is used to describe the electrical characteristic of two sides of the cell membrane, respectively. The combination of two linear circuits via a nonlinear resistor can describe the energy characteristic and firing mode in the flexible membrane of biophysical neurons. Circuit equations are defined and converted into equivalent nonlinear oscillator like a neuron. The voltage difference for the two capacitors can be consistent with the membrane potential for the neuron. The Hamilton energy function for this neuron can be mapped from the field energy in the electronic components, and it is also derived by using Helmholtz's theorem. The neuron can show similar spiking and bursting firing patterns, and uncertain diversity in membrane potentials is effective to support continuous firing patterns and mode transition under external stimulus. Furthermore, noisy disturbance is applied to induce coherence resonance. The results indicate that the lower coefficient variability and higher average energy level supports periodic firing in the neuron under coherence resonance. Therefore, this neuron model with nonlinear membranes (or two-layer form) is more suitable for identifying the biophysical property of biological neuron.