The quality of group interactions in medical problem-based learning in China: the roles of intercultural sensitivity and group ethnic composition.

BACKGROUND: Chinese universities are increasingly recruiting foreign students, and problem-based learning (PBL) is an effective approach to integrating those students. This study focuses on the role of intercultural sensitivity and group ethnic composition on the quality of group interaction in medical problem-based learning in China. METHODS: This paper reports an investigation of the differences in three types of group interaction (exploratory questions, cumulative reasoning, and handling conflict) among 139 s-year medical undergraduates from two backgrounds (Chinese and foreign) in a PBL setting. The roles of intercultural sensitivity, group ethnic composition, and students' personal characteristics including age, gender and ethnicity on students' perceptions of the three types of interaction were quantitatively analyzed. A 35-item questionnaire and demographic survey were administered to second year medical undergraduates. RESULTS: The results indicated that group ethnic composition was a significant negative predictor while intercultural sensitivity was a strong positive predictor of group interactions involving exploratory questions and cumulative reasoning. In addition, group heterogeneity in terms of age and ethnicity were significant predictors of group interaction. CONCLUSIONS: The findings of this study provide insights for strategically designing effective multiethnic group learning environments that encourage interaction and collaboration.

Efficient dehydrogenation of a formic acid-ammonium formate mixture over Au3Pd1 catalyst.

A series of AuPd/C catalysts were prepared and tested for the first time for active and stable dehydrogenation of a formic acid-ammonium formate (FA-AF) mixture. The catalysts with different Au-to-Pd molar ratios were prepared using a facile simultaneous reduction method and characterized using transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was found that the catalytic activity and stability of the Au3Pd1/C catalyst was the best. The initial turnover frequency for the dehydrogenation of the FA-AF mixture over the Au3Pd1/C catalyst can reach 407.5 h-1 at 365 K. The reaction order with respect to FA and AF is 0.25 and 0.55, respectively. The apparent activation energy of dehydrogenation is 23.3 ± 1.3 kJ mol-1. The catalytic activity of the Au3Pd1/C catalyst remains ca. 88.0% after 4 runs, which is much better than the single Pd/C catalyst. The mechanism for the dehydrogenation is also discussed.

Electrochemical preparation of surface molecularly imprinted poly(3-aminophenylboronic acid)/MWCNTs nanocomposite for sensitive sensing of epinephrine.

A nanocomposite with multi-walled carbon nanotubes (MWCNTs) coated with surface molecularly imprinted polymers (MIPs) poly(3-aminophenylboronic acid) (PAPBA) was successfully prepared via potentiodynamic electropolymerization and tested as an effective electrochemical material for epinephrine (EP) detection. The morphology and properties of the sensing material were characterized with scanning electron microscopy and electrochemical impedance spectroscopy. Compared with MWCNTs or non-imprinted polymers PAPBA modified MWCNTs electrodes, the PAPBA(MIPs)/MWCNTs modified electrode showed a lower charge transfer resistance and enhanced electrochemical performance for EP detection. The improved performance can be attributed to the large amount of specific imprinted cavities with boric acid group which can selectively adsorb EP molecule and the synergistic effect between MWCNTs and PAPBA(MIPs). The effects of pH, the molar ratio between monomer and template molecule, the cycle number of electropolymerization, and the accumulation time of the modified electrode on the sensing performance were investigated. It was found that under the optimal conditions, the PAPBA(MIPs)/MWCNTs sensor could effectively recognize EP from many possible interferents of higher concentration within a wide linear range of 0.2-800 µmol·L-1, with low detection limit of 35 nmol·L-1, high sensitivity and good discrimination. The detection of EP in human serum and real injection samples using the PAPBA(MIPs)/MWCNTs sensor also gave satisfactory results.

Clinical and bacteriological features and prognosis of ascitic fluid infection in Chinese patients with cirrhosis.

BACKGROUND: Spontaneous bacterial peritonitis (SBP) and bacterascites (BA) represent frequent and serious complications in cirrhosis patients with ascites. However, few detailed data are available regarding the clinical and bacteriological feature of SBP or BA patients in China. METHODS: We retrospectively analyzed bacteriological and clinical characteristics of patients with SBP and BA at Beijing 302 Hospital in China from January 2012 to December 2015. RESULTS: A total of 600 patients with SBP (n = 408) or BA (n = 192) were enrolled. Patients with BA appeared to have a less severe clinical manifestation and lower mortality rate than patients with SBP. Gram-negative bacteria formed the majority of pathogens in SBP (73.9%) and BA (55.8%) cases. Higher ascitic fluid polymorphonuclear leucocytes (PMN) count and hepatocellular carcinoma were independent risk factors for BA episode progressing to SBP. The concentration of blood urea nitrogen (BUN) was independent risk factor for 30-day mortality of BA patients. For patients with SBP, the independent risk factors for 30-day mortality were age, Model for End-Stage Liver Disease (MELD) score, septic shock and hepatocellular carcinoma. Patients with third-generation cephalosporin or carbapenems resistant infection had a significantly lower survival probability. There were significant differences in clinical characteristics and outcome among the major bacteria. Multivariate analysis showed that patients infected with Klebsiella spp. had higher hazard ratio of 30-day mortality. CONCLUSION: Our study reported the bacteriological and clinical characteristics of patients with SBP and BA. Higher ascitic fluid PMN count and hepatocellular carcinoma were found to be independent risk factors for BA episode progressed to SBP. Outcome of ascitic fluid infection in patients with cirrhosis was influenced by the type of bacteria and antimicrobial susceptibility.

Electrochemical preparation of two nanostructured poly(sulfosalicylic acid) films with different morphologies and properties for selective sensing of dopamine: Comparative study.

Two nanostructured poly(sulfosalicylic acid) (PSA) films were synthesized from room temperature ionic liquid (RTIL) or aqueous solution on a glassy carbon electrode (GCE) via potentiodynamic electropolymerization. The morphology and properties of the PSA films were characterized with scanning electron microscopy (SEM), scanning probe microscopy (SPM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). It was found that solvent had a major influence on the morphology and electrochemical properties of the resultant PSA films. The PSA(Ι) film, which was prepared from RTIL, consists of granular particles with cracks, whereas the PSA(II) film prepared from aqueous solution consists of nano-triangles with a more compact surface. The blocking effect of the PSA(Ι) film for the [Fe(CN)6]3-/4- electrochemical probe is much stronger, and a remarkably enhanced voltammetric response of the [Ru(NH3)6]3+ electrochemical probe can be observed for the PSA(II) film. When it is used to detect dopamine in the presence of a high concentration of ascorbic acid, PSA(II)/GCE has three linear parts with better discrimination and a detection limit of 0.03µM. For PSA(Ι)/GCE, there are two linear parts with a detection limit of 0.05µM. However, the reproducibility and storage stability of PSA(Ι)/GCE are better than those of PSA(ΙI)/GCE.

[Influence of Chaetomium globosmn ND35 fungus fertilizer on physiological characteristics of poplar in replanted soil.] / è¿žä½œåœŸå£¤ä¸­æ–½åŠ çƒæ¯›å£³ND35èŒè‚¥å¯¹æ¨æ ‘ç”Ÿç†ç‰¹æ€§çš„å½±å“.

In the Forestry Experimental Station of Shandong Agricultural University, we determined the photosynthetic physiological and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of one-year-old poplar seedlings under different doses (0.17, 0.33, 0.67, 1.00, 1.33 and 1.67 g·kg-1) of Chaetomium globosmn ND35 fungus fertilizer treatment to study the effects of fungus fertilizer on photosynthesis of poplar in replanted soil. The results showed that with the increase of fungus fertilizer dose, the chlorophyll content of poplar lea-ves (Chl) showed an increasing trend, while the physiological indexes such as electron transport rate (ETR), net photosynthetic rate (Pn), quantum efficiency (Φ), nitrate reductase (NR) activity and root vigor showed an increasing first and then decreasing trend. Meanwhile, the heat dissipation that depended on xanthophyll cycle decreased and non-photochemical quenching (NPQ) increased first and then decreased. When the dose of C. globosmn ND35 fungus fertilizer was 0.67 g·kg-1 or 1.00 g·kg-1, excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions, which improved the energy use efficiency. Applying an appropriate amount (0.67-1.00 g·kg-1) of C. globosmn ND35 fungus fertilizer could improve root physiological activity and light use ability of poplar leaves, which was conducive to the improvement of operating states of photosynthetic apparatus, and then increased the photosynthetic efficiency of the poplar leaves.

Highly lipophilic 3-epi-betulinic acid derivatives as potent and selective TGR5 agonists with improved cellular efficacy.

AIM: TGR5 is a G protein-coupled receptor that is expressed in intestinal L-cells and stimulates glucagon-like peptide 1 (GLP-1) secretion. TGR5 may represent a novel target for the treatment of metabolic disorder. Here, we sought to design and synthesize a series of TGR5 agonists derived from the natural product betulinic acid. METHODS: A series of betulinic acid derivatives were designed and synthesized. A cAMP assay was established using a HEK293 cell line expressing human TGR5. Luciferase reporter assay was established using HEK293 cells transfected with plasmids encoding human FXR and luciferase reporter. A human intestinal L-cell line NCI-H716 was used to evaluate the effects of the betulinic acid derivatives on GLP-1 secretion in vitro. RESULTS: Biological data revealed that the 3-α-OH triterpenoids consistently show increased potency for TGR5 compared to their 3-ß-OH epimers. 3-OH esterification increased the lipophilicity and TGR5 activity of 3-α betulinic derivatives and enhanced the activity differences between 3-α and 3-ß derivatives. The 3-α-acyloxy betulinic acids also exhibited a significant dose-dependent GLP-1 secretion effect. CONCLUSION: This study demonstrates that highly lipophilic 3-epi-betulinic acid derivatives can be potent and selective TGR5 agonists with improved cellular efficacy, and our research here provides a new strategy for the design and development of potent TGR5 agonists.

Discovery and characterization of novel small molecule agonists of G protein-coupled receptor 119.

AIM: GPR119 is a G protein-coupled receptor (GPCR) that is highly expressed in pancreatic ß-cells and intestinal L-cells and facilitates glucose-stimulated insulin secretion (GSIS). GPR119 may represent a novel target for the treatment of metabolic disorders. Here, we sought to identify novel small-molecule GPR119 agonists. METHODS: A cell-based high-throughput screening assay was established using HEK293 cells stably expressing GPR119 and pCRE-luc reporter plasmid (HEK293/GPR119/pCRE-luc). A compound library composed of 1440 compounds was screened. Mouse ß-cell line MIN-6 and isolated mouse islets were used to evaluate the effects of candidate compounds on GSIS in vitro. RESULTS: Three compounds with novel structures (ZSY-04, -06, and -13) were found to activate GPR119-mediated signaling and to induce GPR119 desensitization. The EC50 values of ZSY-04, -06, and -13 in stimulating intracellular cAMP accumulation in HEK293/GPR119 cells were 2.758, 3.046, and 0.778 µmol/L, respectively. Furthermore, all three compounds displayed high selectivity for GPR119, and did not activate other 9 GPCRs tested. Moreover, all three compounds significantly increased GSIS in both MIN-6 mouse ß-cells and isolated mouse islets at concentration of 10 µmol/L. CONCLUSION: Three novel small-molecule GPR119 agonists (ZSY-04, -06, and -13) with high receptor selectivity and capacity to induce GSIS in vitro were discovered. These compounds are potential candidates to be structurally optimized into drugs for the treatment of type 2 diabetes.

[Response processes of Aralia elata photosynthesis and transpiration to light and soil moisture].

By using CIRAS-2 portable photosynthesis system, the light response processes of Aralia elata photosynthesis and transpiration under different soil moisture conditions were studied, aimed to understand the adaptability of A. elata to different light and soil moisture conditions. The results showed that the response processes of A. elata net photosynthetic rate (Pn), transpiration rate (Tr), and water use efficiency (WUE) to photon flux density (PFD) were different. With the increasing PFD in the range of 800-1800 micromol x m2(-2) x s(-1), Pn changed less, Tr decreased gradually, while WUE increased obviously. The light saturation point (LSP) and light compensation point (LCP) were about 800 and 30 micromol m(-2) x s(-1), respectively, and less affected by soil water content; while the apparent photosynthetic quantum yield (Phi) and dark respiratory rate (Rd) were more affected by the moisture content. The Pn and WUE had evident threshold responses to the variations of soil water content. When the soil relative water content (RWC) was in the range of 44%-79%, A. elata could have higher levels of Pn and WUE.

[Growth process and diameter structure of Pinus tabulaeformis forest for soil and water conservation in Loess Plateau Hilly regions].

Through stem analysis of sample trees, the biomass, growth process, and diameter structure of two 21 years old Pinus tabulaeformis forests growing on the shady and sunny slopes in Loess Plateau hilly and gully regions were investigated. The results showed that there were distinct differences between these two forests in their tree height, diameter at breast height (DBH), and timber volume. The forest biomass, growth status, and diameter structure on shady slope were superior to those on sunny slope. The fast-growing period of tree height all appeared in the period of 9-13 years, and after 13 years, the annual increment of tree height was larger in shady slope forest than in sunny slope forest, with the increment in the 21st year being 0.26 and 0.1, respectively. The DBH growth of the two forests was declined greatly after 13 years, but the decrement was obviously less in shady slope forest than in sunny slope forest. After 17 years, the annual increment of DBH growth was larger in shady slope forest than in sunny slope forest, with the values being 0.46 cm x a(-1) and 0.27 cm x a(-1), respectively in the 21st year. Before 13 years, there was little difference in the increment of timber production between the two forests, but the increment after 13 years was larger in shady slope forest than in sunny slope forest, with the values of 0.0023 m3 and 0.0015 m3, respectively in the 21st year. The summit of DBH distribution curve was all partial to left, but the skewness of shady slope forest (SK = 0.75) was lower than that of sunny slope forest (SK = 1.03), and the kurtosis of shady slope forest (K = 1.05) was higher than that of sunny slope forest (K = 0.94), indicating that sunny slope forest had a larger stand density than shady slope forest.

Scanning electron microscopic observation: three-dimensional architecture of the collagen in hepatic fibrosis rats.

BACKGROUND: In the process of hepatic fibrosis, the accumulation of collagen fibers is strongly related to the hepatic function. The aim of this study was to investigate the three-dimensional architecture of the collagen network in the liver of rats with hepatic fibrosis. METHODS: Healthy adult male Wistar rats (n = 32) were randomly divided into a control group (n = 16) and a hepatic fibrosis group (n = 16). In the control group, the rats were treated with peanut oil while the rats in hepatic fibrosis group were treated for 10 weeks with 60% CCl(4) diluted in peanut oil. The quantity of collagen fibers was detected by Western blotting; distribution of the collagen was detected by sirius red staining and polarized microscope; the three-dimensional architecture of collagen in the liver was observed under the scanning electron microscope after fixed tissues were treated with cell-maceration using NaOH. Statistical analysis was performed using the u test. RESULTS: The quantity of collagen fibers increased significantly in the hepatic fibrosis group. With the aggravation of hepatic fibrosis, collagen fibers gradually accumulated. They interlaced the reticulation compartment and formed a round or ellipse liver tissue conglomeration like a grape framework that was disparate and wrapped up the normal liver lobule. The deposition of collagen fibers was obvious in adjacent hepatic parenchyma, especially around the portal tracts. CONCLUSION: Our experiment showed the collagen proliferation and displays clearly the three-dimensional architecture of collagen fibers in rat liver with hepatic fibrosis by scanning electron microscope. It can provide a morphological foundation for the mechanisms of changed haemodynamics and portal hypertension in hepatic fibrosis.