聚乳酸/聚碳酸丁二醇酯/壳聚糖复合纤维膜的制备及表征

通过静电纺丝法制备聚乳酸(PLA)/聚碳酸丁二醇酯(PBC)/壳聚糖(CS)复合纤维膜。通过扫描电子显微镜研究了复合纤维的微观结构,当CS含量为0.08%时,复合纤维膜表现出良好的纤维直径分布。傅里叶变换红外光谱仪分析表明,PLA与PBC之间没有化学反应,并且CS被成功地添加到PLA/PBC中。PLA/PBC/CS复合纤维膜表现出优异的热学性能、力学性能和亲水性能,随着CS含量增加,热稳定性和力学性能逐渐增大,而接触角逐渐减小。此外,PLA/PBC/CS复合纤维膜在抑菌测试中显示出对大肠杆菌(E.coli)和金黄色葡萄球菌(S.aureus)的高抗菌活性。

Generalized Demodulation Transform for Bearing Fault Diagnosis Under Nonstationary Conditions and Gear Noise Interferences

It is a challenging issue to detect bearing fault under nonstationary conditions and gear noise interferences. Meanwhile, the application of the traditional methods is limited by their deficiencies in the aspect of computational accuracy and e ciency, or dependence on the tachometer. Hence, a new fault diagnosis strategy is proposed to remove gear interferences and spectrum smearing phenomenon without the tachometer and angular resampling technique. In this method, the instantaneous dominant meshing multiple(IDMM) is firstly extracted from the time-frequency representation(TFR) of the raw signal, which can be used to calculate the phase functions(PF) and the frequency points(FP). Next, the resonance frequency band excited by the faulty bearing is obtained by the band-pass filter. Furthermore, based on the PFs, the generalized demodulation transform(GDT) is applied to the envelope of the filtered signal. Finally, the target bearing is diagnosed by matching the peaks in the spectra of demodulated signals with the theoretical FPs. The analysis results of simulated and experimental signal demonstrate that the proposed method is an e ective and reliable tool for bearing fault diagnosis without the tachometer and the angular resampling.

Isoflavone Attenuates the Nuclear Transcription Factor Kappa B (NF-<i>κ</i>B) Activation on MPP⁺-Induced Apoptosis of PC12 Cells

Objective: To explore the underlying molecular mechanisms of cellular response to the challenge by 1-methyl-4-phenylpyridinium (MPP+)-induced apoptosis of PC12 cells, an in vitro cell model for Parkinson’s disease, and the effect of NF-κB activation on the protection of Parkinson’s disease by Isoflavone (I). Methods: PC12 cells were used to establish the cell model of Parkinson’s disease, and are divided into five groups: control group;MPP+ group;I (Isoflavone) + MPP+ group;I group;SN-50 + MPP+ group. The content of NF-κB in PC12 cells was determined by immunocytochemistry;The viability of PC12 cells after treated with cell-permeable NF-κB inhibitor SN-50 and cell viability were measured by MTT assay;the expression levels of NF-κB p65 in cytoplasm and nuclear fractions were evaluated by western blot analysis;the mRNA expression of NF-κB p65 was analyzed by in situ hybridization (ISH). Results: Compared with the control group, the protein of NF-κB p65 both in cytoplasm and in nuclei was significantly higher than in I + MPP+ and MPP+ groups;similarly, the mRNA expression level of NF-κB p65 gene was also significantly higher;moreover, the protein expression of NF-κB p65 was much lower in I group (P + group, the protein of NF-κB p65 was significantly lower in I + MPP+ group, the mRNA expression level of NF-κB p65 gene was also significantly lower, and the protein expression level of NF-κB p65 was much lower in I + MPP+ group (P + group (P > 0.05). Conclusion: NF-κB activation is essential to MPP+-induced apoptosis in PC12 cells;but Isoflavone can inhibit the cell damage to some extent to execute its protective function, which may be involved in nigral neurodegeneration in patients with Parkinson’s disease.

Breeding and Application of Guidan 903,a New High-yield and Good-quality Maize Variety

To meet the demand of maize production in Guangxi and even the southwest region of China and realize the upgrading and undating of maize varieties which will continuously improve the yield and quality of maize,a new big-ear maize variety Guidan 903 with high yield,stable yield and good quality was established by the Maize Research Institute of Guangxi Academy of Agricultural Sciences with two self-selected inbred line GRL17349 and GRL21191 as female and male parents seperately.The average yield of this variety were 7429.5 and 7000.5 kg/hm^(2)in Guangxi Maize Regional Trial and Production Test respectively,which increased by 6.3%and 5.6%than the control(Guidan162).It was approved by Guangxi Zhuang Autonomous Region Crop Variety Certification Committee in June 2020(Approval No.Gui sheng yu 2020083).Determined by the Cereal Quality Supervision and Testing Center of Ministry of Agriculture and Rural Affairs(Bejjing),the grain bulk density,ratio of crude protein,crude fat,crude starch and lysine of Guidan 903 were 782 g/L,9.41%,6.19%,71.45%,0.35%respectively.This variety has the characterisics of strong resistance to collapse and disease,good quality,high and stable yield and wide adaptability.Furthermore,its seed yield is high with easy production technology and low cost.

Comparison of the Pull-out Strength Between a Novel Micro-dynamic Pedicle Screw and a Traditional Pedicle Screw by Using Pull Out Test and Micro-CT

Objective To investigate the effectiveness of the micro-dynamic pedicle screw for the prevention of loosening between the screw and bone surface in lumbar spinal fusion.For this evaluation,the peek pull-out force(PPF)after fatigue resistance testing at different cycles and semidiameter of screw insertion area of micro-CT image was compared between the micro-dynamic and traditional pedicle screws.Methods Forty lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows:15 vertebrae underwent instant pull-out testing(group A,traditional vs.group B,micro-dynamic);15 vertebrae underwent pull-out test after 5000-cyclic fatigue loading(group C,traditional vs.group D,micro-dynamic);and 10 vertebrae underwent pull-out test after 10000-cyclic fatigue loading(group E,traditional vs.group F,micro-dynamic).All vertebrae that after fatigue loading were scanned by using micro-ct to check the semidiameter of screw insertion area.The PPF,normalized PPF(PPFn),bone mineral density(BMD)and diameter of screw insertion area were compared between all groups.Results The BMD showed a weak significant correlation with PPF(r=0.252,P=0.024).The PPF in groups A and B(P=0.485),and groups C and D(P=0.184)did not show significant difference.However,the PPF in group F was significantly greater than that measured in group E(P=0.005).The PPFn of groups A,C,and E significantly decreased as the number of cycles increased(P=0.015).Meanwhile,the PPFn of groups B,D,and F remained consistent regardless of the number of cycles(P=0.367). The semidiameter of traditional pedicle screw insertion area was significantly larger than that of micro-dynamic pedicle screw insertion area(P<0.001).Conclusions This study compared the performance of a micro-dynamic pedicle screw versus that of a traditional pedicle screw using pull-out testing and micro-CT.The results showed that the micro-dynamic pedicle screw provides similar resistance in lowcycle fatigue testing and favorable resistance in high-cycle fatigue testing versus the traditional pedicle screw.The micro-dynamic pedicle screw provides stronger fixation stability versus the traditional pedicle screw,especially in high-cyclic fatigue loading condition versus the traditional pedicle screws.

Effect of chemical ordering annealing on superelasticity of Ni-Mn-Ga-Fe ferromagnetic shape memory alloy microwires

Ni50Mn25Ga20Fe5 ferromagnetic shape memory alloy microwires with diameters of^30-50μm and grain sizes of^2-5μm were prepared by melt-extraction technique.A step-wise chemical ordering annealing was carried out to improve the superelasticity strain and recovery ratio which were hampered by the internal stress,compositional inhomogeneity,and high-density defects in the as-extracted Ni50Mn25Ga20Fe5 microwires.The annealed microwires exhibited enhanced atomic ordering degree,narrow thermal hysteresis,and high saturation magnetization under a low magnetic field.As a result,the annealed microwire showed decreased superelastic critical stress,improved reversibility,and a high superelastic strain(1.9%)with a large recovery ratio(>96%).This kind of filamentous material with superior superelastic effects may be promising materials for minor-devices.

Discussions on the Path of Precise Poverty Alleviation in Dongxiang County

By means of questionnaire survey,household interview,conference exchange and field investigation,this paper makes a detailed investigation on the development status and existing problems of industry poverty alleviation and science and technology poverty alleviation in Dongxiang County. This paper puts forward the precise poverty alleviation path of Dongxiang County from the aspects of industry poverty alleviation,science and technology poverty alleviation,education poverty alleviation,poverty alleviation through ecology,relocation poverty alleviation and so on.

Variations of energy metabolism and adenosine Triphosphatase activity in gastric mucosa in chronic atrophic gastritis rats with Qi deficiency and blood stasis syndrome and effect of Zhiweifangbian capsule

OBJECTIVE: To study the effects of Zhiweifangbian (ZWFB) capsule on lactic dehydrogenase (LDH), succinic dehydrogenase (SDH) and ATPase activities in gastric mucosa of chronic atrophic gastritis (CAG) rats with Qi deficiency and blood stasis syndrome. METHODS: Totally 90 rats were randomly divided into 2 groups: normal group (n=10) and modelgroup (n=80). The CAG rat model of Qi deficiency and blood stasis type was induced by synthetic methods. After modeling for 12 weeks and the successful CAG model was determined, the CAG model rats were divided by random number table into model group (MG), ZWFB high-dose group (ZWFBH), ZWFB middle-dose group (ZWFBM), ZWFB low-dose group (ZWFBL) and Weimeisu group (WM), 9 rats in each group. The rats in the normal and model groups were intragastrically administrated with distilled water, 10 mL/kg every day; the ZWFB high-dose group with ZWFB, 0.6 g/ kg -1 · d -1 ; the ZWFB middle-dose group with ZWFB, 0.3 g/kg -1 · d -1 ; the ZWFB low-dose group with ZWFB, 0.15 g/kg -1 · d -1 , and the WM group with suspension of WM , 0.25 g/kg -1 · d -1 . The treatment was given for 90 consecutive days. Then general survival states were observed and the activities of LDH, SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase in gastric mucosa tissue were detected. RESULTS: Compared with the normal group, activity of LDH in the gastric mucosa (P<0.05) and activities of SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase significantly decreased in the normal group (P<0.05). Compared with the model group the activity of LDH decreased and activities of SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase significantly increased in the high dose ZWFB group (P<0.05). CONCLUSION: ZWFB capsule can promote energy metabolism and ATPase activity in the gastric mucosa cell, so as to protect the function of the gastric mucosa cell.