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【Objective】 The geometry of side ventilation windows is an important design parameter of greenhouse and this paper investigates the impact of their aspect ratio on air circulation in terraced greenhouses. 【Method】 The study is based on butterfly windows of terraced greenhouses in Guangzhou, using numerical simulation and experimental data measured from a greenhouse (Window C). We modelled five aspect ratios and compared the numerical simulations with experimental data. Air circulation in the greenhouse is quantified using non-uniformity coefficients. 【Result】 The average errors between the simulated and measured temperature and wind speed are 2.48% and 8.76% respectively, and their associated root mean square errors are 1.10 ℃ and 2.1×10-3 m/s, respectively. Changes in the aspect ratio do not result in significant effect on average temperature in the greenhouses, but affect temperature variation noticeably. Among the five aspect ratios we compared, Window A gives the greatest average wind speed and highest wind uniformity coefficient. Compared with Window C, it increase average wind speed by 23% and the wind speed uniformity coefficient by 41%. 【Conclusion】 Our results show that reducing the aspect ratio of the side ventilation window as currently used by local farmers can effectively increase the uniformity of both temperature and wind speed in the greenhouse.

Background: To optimize the critical value of test items using FOCUS-PDCA (find, organize, clarify, understand, select, plan, do, check and act), and to set the personalized critical value of the test for different departments. Methods: We searched for literature reporting on the critical value and FOCUS-PDCA published over recent 5 years in order to understand the significance and status quo of critical value and FOCUS-PDCA. We also collected and analyzed the critical value data of hospital tests performed in Sichuan province hospitals in 2019, which were later compared to data from 2020 to determine the FOCUSPDCA cycle. Results: The proportion of critical values in the whole hospital decreased from 3.5% before optimization to 2.5% to 3% after optimization. The critical values of ICU, hematology, nephrology, urology, and neonatal departments after optimization significantly decreased compared with those before optimization, while the critical values of cardiac surgery, emergency ICU, cardiology, and neurosurgery ICU showed no significant difference before and after optimization. Contrary, the critical values of the infection department after optimization significantly increased before optimization. Conclusions: FOCUS-PDCA can effectively optimize the critical value of test items, which is beneficial for rational utilization of medical resources.

ObjectiveIn order to collect and analyze the suggestions and opinions in re-evaluation for the food additive standard system of China, and provide references for the revisions of the standards.MethodsFeedbacks were collected through the "National Food Safety Standard Track and Re-evaluation Platform" from all aspects of GB 2760—2014, including product standards, labeling standards and production specifications. The rationality and feasibility of the opinions and suggestions were analyzed, and suggestions are proposed for standard revisions.ResultsThis study collected about 207 opinions and suggestions through the platform from 2019 to 2020, mainly focusing on the application of GB 2760 and the content of product quality specifications, and analyzed the rationality and feasibility of the opinions.ConclusionThe tracking and re-evaluation of standard is an important means to understand the implementation effect of standard. The reasonable opinions from the tracking and re-evaluation of standard provide a reference for the revision of the standard, and at the same time, the high-quality completion of the tracking and re-evaluation could improve the pertinence and practicality of publicity and implementation of national food safety standard.

ObjectiveAnalyze the food safety standard management of food additives nitrate and nitrite used in meat products.MethodsThe future direction of national food safety standard management is discussed through the analysis of the standards of Codex Alimentarius, the United States of America, Canada, the European Union, Australia, New Zealand, Japan, Republic of Korea and China, combined with risk assessment results, monitoring data and food poisoning incident data.ResultsFrom the perspective of process control, operability of final product testing and practical detection at import-export ports, the United States of America, Canada, Australia and New Zealand set the maximum use level, while Japan and the Republic of Korea set the maximum residual level. At the same time, the European Union sets the maximum use level or residual level according to the specific food products. China sets both the maximum use level and the residual level, and the N-dimethyl nitrosamine is regulated as pollutant in the corresponding food categories. The dietary exposure result indicates that nitrate and nitrite used as food additives have a low contribution to dietary exposure, therefore they pose low food safety risks to the public.ConclusionAlthough maintaining the maximum use level and residual level of nitrate and nitrite in the food safety standard is in line with the process control principles and actual regulatory requirements, it is still recommended to continue to carry out research on improvement of food processing technology and alternatives of these food additives, and it is necessary to go on promoting food safety education for consumers and catering industry to prevent food poisoning caused by misuse of nitrites and nitrates.

Objective To detect the expression of neurogenin 3 in gastric cancer tissues and cultured gastric cancer cells and determine its role in regulating the malignant phenotype of gastric cancer cells. Methods Immunohistochemical staining was used to detect the expression of neurogenin 3 in tissue specimens of intestinal metaplasia gastric mucosa and gastric cancer. The expression of neurogenin 3 in human gastric mucosal epithelial cells (GES-1) and in gastric cancer cell lines with different levels of differentiation was detected using real-time PCR and Western blotting. In gastric cancer MKN-28 cells, the effect of neurogenin 3 gene silencing mediated by lentivirus transfection on the expression of cell differentiation inhibitor of DNA binding or differentiation (Id-1) was detected using real-time PCR. The changes in the proliferation of the cells were assessed using EdU cell proliferation assay and cell colony formation assay, and the migration and invasion of the transfected cells were evaluated with a scratch assay and Transwell assay. Results Neurogenin 3 was lowly expressed in poorly differentiated gastric cancer tissues but highly expressed in adjacent tissues, intestinal metaplasia gastric mucosa tissues and moderately to well differentiated gastric cancer tissues (P < 0.001). Neurogenin 3 expression in gastric cancer tissue showed no significant correlation with the patients' gender, age or tumor size (P>0.05), but was significantly correlated with the level of tumor differentiation (P < 0.001, r=0.412), lymph node metastasis (P < 0.05, r=-0.180) and TNM staging (P < 0.001, r=-0.431). The expression of neurogenin 3 in well differentiated gastric cancer MKN-28 and gastric GES-1 cell lines was significantly higher than that in moderately or poorly differentiated gastric cancer SGC-7901, MKN-45 and BGC-823 cell lines. Neurogenin 3 silencing in MKN-28 cells resulted in a lower level of cell differentiation, a significantly increased expression of Id-1 (P < 0.001) and significantly enhanced cell proliferation, migration and invasion (P < 0.01). Conclusion Neurogenin 3 silencing can inhibit the differentiation and promote the proliferation, migration and invasion of gastric cancer cells in vitro.

Objective To investigate the effect of astrocyte-microglia crosstalk mediated by complement C3/C3aR signaling on hydrocephalus after germinal matrix hemorrhage (GMH) in newborn rats. Methods GMH was induced in post-natal day 7 SD rats by collagenase Ⅶ-S injection into the ganglionic eminence. We detected the changes in the expression of periventricular C3 and C3aR over time after GMH, and observed the effect of intraperitoneal injection of C3aRA (a selective C3aR antagonist) on hydrocephalus using magnetic resonance imaging (MRI). The learning and memory functions of the rats were tested after the treatment using Morris water maze test, and the expression of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1) and aquaporin 4 in the brain tissues were detected using Western blotting at different time points after GMH. Results The neonatal rats with GMH showed significantly up-regulated expression of C3 and C3aR around the cerebral ventricles and increased expression of IL-1β, IL-6, TNF-α and TGF-β1 in the brain, presenting also with obvious lateral ventricle dilation, compression of the cortex and hippocampus, and impairment of the learning and memory functions. Treatment of the rats with C3aRA obviously decreased C3 and C3aR expression, alleviated hydrocephalus, improved the neurological deficits, and reduced the expression of the inflammatory factors in the brain. GMH caused obvious ectopic expression of aquaporins 4 and increased its expression level on the astrocytes, and C3aRA treatment significantly improved the abnormal expression of aquaporins 4. Conclusion GMH causes the astrocytes to up-regulate and release C3, which binds to C3aR on the microglia to promote inflammation and aggravate hydrocephalus. The ectopic expression of aquaporin 4 in astrocytes may play an important role in the occurrence of hydrocephalus following GMH. rats newborn

High-pressure studies on elements play an essential role in superconductivity research, with implications for both fundamental science and applications. Here we report the experimental discovery of surprisingly low pressure driving a novel germanium allotrope into a superconducting state in comparison to that for α-Ge. Raman measurements revealed structural phase transitions and possible electronic topological transitions under pressure up to 58 GPa. Based on pressure-dependent resistivity measurements, superconductivity was induced above 2 GPa and the maximum Tc of 6.8 K was observed under 4.6 GPa. Interestingly, a superconductivity enhancement was discovered during decompression, indicating the possibility of maintaining pressure-induced superconductivity at ambient pressure with better superconducting performance. Density functional theory analysis further suggested that the electronic structure of Ge (oP32) is sensitive to its detailed geometry and revealed that disorder in the β-tin structure leads to a higher Tc in comparison to the perfect β-tin Ge.

Process of “high temperature carbonization and low temperature chlorination”, which was considered to be one of the most promising technologies, could extracte more than 70% titanium from the furnace slag containing TiO2 10% - 30%. TiC-containing slag was the product of high temperature carbonization, and to meet the requirement of the following chlorination process, it needs to be crushed and grounded to a suitable size distribution. The air jet pulverization of TiC-containing slag was studied in this paper. On the one hand, By CFD numerical simulation, the distribution regularity of nozzle flow field about the main crushing equipment was obtained with different throat diameters and crushing gas pressures. On the other hand, the influences of nozzle throat diameter, crushing pressure, and collision angles on the particle size of the powder were studied by experiment. With the better parameters, the particle size distribution of the product powder was uniform.