47 results on '"Shi, Xing"'
Search Results
2. Pd-Catalyzed Direct Modification of an Anti-Alzheimer’s Disease Drug: Synthesis and Biological Evaluation of α‑Aryl Donepezil Analogues
- Author
-
Lin-Xi Wan, Shi-Xing Miao, Zhen-Xiang He, Xiaohuan Li, Xian-Li Zhou, and Feng Gao
- Subjects
Chemistry ,QD1-999 - Published
- 2021
- Full Text
- View/download PDF
3. Candidate Effectors from Botryosphaeria dothidea Suppress Plant Immunity and Contribute to Virulence
- Author
-
Chuan-Jie Zhang, Shi-Xing Wang, Yan-Na Liang, Sheng-Hui Wen, Bao-Zhu Dong, Zheng Ding, Li-Yun Guo, and Xiao-Qiong Zhu
- Subjects
Botryosphaeria dothidea ,host–pathogen interaction ,plant immunity ,effector ,virulence ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Fungal effectors play important roles in host–pathogen interactions. Botryosphaeria dothidea is an ascomycetous fungus that is responsible for the diseases of hundreds of woody plant species, including apple ring rot, which seriously affects apples worldwide. However, little is known about the effectors of B. dothidea. In this study, we analyzed the B. dothidea genome and predicted 320 candidate effector genes, 124 of which were successfully amplified and cloned. We investigated the effects of these genes on plant cell death in Nicotiana benthamiana while using a transient expression system. Twenty-four hours after initial inoculation with Agrobacterium tumefaciens cells carrying candidate effectors, the infiltrated leaves were challenged with A. tumefaciens cells carrying the BAX gene. In total, 116 candidate effectors completely inhibited, while one partially inhibited, the programmed cell death (PCD) of N. benthamiana induced by BAX, whereas seven candidate effectors had no effect. We then further tested seven candidate effectors able to suppress BAX-triggered PCD (BT-PCD) and found that they all completely inhibited PCD triggered by the elicitors INF1, MKK1, and NPK1. This result suggests that these effectors were activated in order to suppress pathogen-associated molecular pattern-triggered immunity. The signal peptides of these candidate effectors exhibited secretory activity in yeast (pSUC2 vector). Moreover, the respective deletion of Bdo_11198 and Bdo_12090 significantly reduced the virulence of B. dothidea. These results suggest that these effectors play important roles in the interaction of B. dothidea with its hosts.
- Published
- 2021
- Full Text
- View/download PDF
4. 1‐Hydroxypyrene mediates renal fibrosis through aryl hydrocarbon receptor signalling pathway
- Author
-
Xia-Qing Wu, Ying-Yong Zhao, Hua Miao, Xiao-Yong Yu, Yan-Long Zhao, Dan-Qian Chen, Wei Su, Yuan Zhang, Shougang Zhuang, Yan Guo, You-Quan Shang, Jia-Rong Mao, Jin Zhao, Nosratola D. Vaziri, Ming Gao, Huan-Qiao Zhang, Gang Cao, Yan-Ni Wang, Li Zhang, Shi-Xing Ma, Jin-Hua Zhang, and Lin Chen
- Subjects
Metabolite ,CYP1B1 ,Renal function ,Pharmacology ,urologic and male genital diseases ,Small hairpin RNA ,Mice ,chemistry.chemical_compound ,Cytochrome P-450 CYP1A1 ,medicine ,Renal fibrosis ,Animals ,Humans ,Renal Insufficiency, Chronic ,Kidney ,Pyrenes ,biology ,medicine.disease ,Aryl hydrocarbon receptor ,Fibrosis ,Rats ,medicine.anatomical_structure ,Receptors, Aryl Hydrocarbon ,chemistry ,biology.protein ,Kidney disease - Abstract
BACKGROUND AND PURPOSE In chronic kidney disease (CKD), patients inevitably reach end-stage renal disease and require renal transplant. Evidence suggests that CKD is associated with metabolite disorders. However, the molecular pathways targeted by metabolites remain enigmatic. Here, we describe roles of 1-hydroxypyrene in mediating renal fibrosis. EXPERIMENTAL APPROACH We analysed 5406 urine and serum samples from patients with Stage 1-5 CKD using metabolomics, and 1-hydroxypyrene was identified and validated using longitudinal and drug intervention cohorts as well as 5/6 nephrectomised and adenine-induced rats. KEY RESULTS We identified correlations between the urine and serum levels of 1-hydroxypyrene and the estimated GFR in patients with CKD onset and progression. Moreover, increased 1-hydroxypyrene levels in serum and kidney tissues correlated with decreased renal function in two rat models. Up-regulated mRNA expression of aryl hydrocarbon receptor and its target genes, including CYP1A1, CYP1A2 and CYP1B1, were observed in patients and rats with progressive CKD. Further we showed up-regulated mRNA expression of aryl hydrocarbon receptor and its three target genes, plus up-regulated nuclear aryl hydrocarbon receptor protein levels in mice and HK-2 cells treated with 1-hydroxypyrene, which caused accumulation of extracellular matrix components. Treatment with aryl hydrocarbon receptor short hairpin RNA or flavonoids inhibited mRNA expression of aryl hydrocarbon receptor and its target genes in 1-hydroxypyrene-induced HK-2 cells and mice. CONCLUSION AND IMPLICATIONS Metabolite 1-hydroxypyrene was demonstrated to mediate renal fibrosis through activation of the aryl hydrocarbon receptor signalling pathway. Targeting aryl hydrocarbon receptor may be an alternative therapeutic strategy for CKD progression.
- Published
- 2021
5. Pd-Catalyzed Direct Modification of an Anti-Alzheimer’s Disease Drug: Synthesis and Biological Evaluation of α-Aryl Donepezil Analogues
- Author
-
Shi-Xing Miao, Lin-Xi Wan, Xian-Li Zhou, Feng Gao, Xiao-Huan Li, and Zhen-Xiang He
- Subjects
chemistry.chemical_classification ,Ketone ,Aché ,General Chemical Engineering ,General Chemistry ,Pharmacology ,Acetylcholinesterase ,Neuroprotection ,language.human_language ,Article ,chemistry.chemical_compound ,Chemistry ,chemistry ,Docking (molecular) ,Toxicity ,medicine ,language ,Donepezil ,QD1-999 ,Butyrylcholinesterase ,medicine.drug - Abstract
Palladium/BuAd2P efficiently catalyzed the direct α-arylation of ketone in the anti-Alzheimer's disease drug donepezil, leading to 15 aryldonepezil analogues exhibiting high selective inhibition of acetylcholinesterase (AChE). The cell-based assays revealed that the 3-methylpridinyl analogue (12) shows significantly lower toxicity compared to donepezil and remarkable neuroprotective activity against H2O2-induced damage in SH-SY5Y cells. Docking results of compound 12 also interpreted the possible mechanism of the selective inhibition between AChE and butyrylcholinesterase (BuChE).
- Published
- 2021
6. Pd-Catalyzed Direct Diversification of Natural Anti-Alzheimer’s Disease Drug: Synthesis and Biological Evaluation of N-Aryl Huperzine A Analogues
- Author
-
Feng Gao, Shi-Xing Miao, Lin-Xi Wan, Zhen-Xiang He, Xiaohuan Li, and Xian-Li Zhou
- Subjects
Pharmacology ,Natural product ,Stereochemistry ,Aryl ,Organic Chemistry ,Pharmaceutical Science ,Acetylcholinesterase ,Neuroprotection ,In vitro ,Analytical Chemistry ,chemistry.chemical_compound ,Complementary and alternative medicine ,chemistry ,Drug Discovery ,medicine ,Molecular Medicine ,Lead compound ,IC50 ,Huperzine A ,medicine.drug - Abstract
The first systematic direct diversification of a complex natural product by metal-catalyzed N-H functionalization was carried out. A new series of N-(hetero)aryl analogues (1-32) of the natural anti-Alzheimer's disease drug huperzine A (HPA) was prepared via palladium-catalyzed Buchwald-Hartwig cross-coupling reactions of HPA with various aryl bromides in good yields. Most of the N-aryl-huperzine A (N-aryl-HPA) analogues showed good acetylcholinesterase (AChE) inhibitory activity in in vitro experiments. Three arylated huperzine A analogues (14, 19, and 30) exhibited stronger anti-AChE activity than HPA. The 5-methoxy-2-pyridyl analogue (30) displayed the most potent AChE inhibition activity, with an IC50 value of 1.5 μM, which was 7.6-fold more active than HPA. Compound 30 also exhibited better neuroprotective activity for H2O2-induced damage in SH-SY5Y cells than HPA. Structure-activity relationship analysis suggested that the electron density of the installed aromatic ring or heteroaromatic ring played a significant role in inducing the AChE inhibition activity. Overall, compound 30 showed the advantages of easy synthesis, high potency and selectivity, and improved neuroprotection, making it a potential huperzine-type lead compound for Alzheimer's disease drug development.
- Published
- 2021
7. Circular RNA circVEGFC accelerates high glucose-induced vascular endothelial cells apoptosis through miR-338-3p/HIF-1α/VEGFA axis
- Author
-
Cong Cao, Hua Wei, Minglv Meng, Xi Wei, Xiao-Juan Wei, Hong-Mian Li, Biaoliang Wu, Shi-Xing Gu, and Lianxin Meng
- Subjects
Vascular Endothelial Growth Factor A ,Aging ,vascular endothelial cells ,Vascular Endothelial Growth Factor C ,Apoptosis ,circVEGFC ,Umbilical vein ,Hypoxia-Inducible Factor 1-Alpha ,Transcription (biology) ,Circular RNA ,Human Umbilical Vein Endothelial Cells ,Humans ,Transcription factor ,Gene knockdown ,Chemistry ,Endothelial Cells ,circular RNA ,RNA, Circular ,Cell Biology ,Hypoxia-Inducible Factor 1, alpha Subunit ,VEGF ,high glucose ,Up-Regulation ,Cell biology ,MicroRNAs ,Vascular endothelial growth factor A ,Glucose ,Gene Expression Regulation ,Research Paper - Abstract
More and more findings illustrate the critical roles of circular RNA (circRNA) in diabetes mellitus (DM) and its complications. A major pathological characteristic for DM is the apoptosis of endothelial cells (ECs) induced by high glucose (HG), however, the function of circRNA in the ECs' phenotypes is still elusive. Here, this study identified an up-regulated circRNA (circVEGFC) in the HG-induced human umbilical vein endothelial cells (HUVECs). Functionally, knockdown of circVEGFC alleviated the apoptosis and recovered the proliferation in HUVECs induced by HG administration. Mechanistically, circVEGFC functioned as the sponge of miR-338-3p, and miR-338-3p was found to target the 3'-Untranslated Regions (3'-UTR) of hypoxia inducible factor 1 alpha (HIF-1α). HIF-1α, a critical transcription factor in DM, could activate the transcription of vascular endothelial growth factor A (VEGFA) and promote its protein product. In conclusion, these findings reveal the promotion of circVEGFC/miR-338-3p/HIF-1α/VEGFA axis in the HG-induced ECs' apoptosis, providing a potential treatment strategy for ECs' damage in DM.
- Published
- 2020
8. P2RY2 Alleviates Cerebral Ischemia-Reperfusion Injury by Inhibiting YAP Phosphorylation and Reducing Mitochondrial Fission
- Author
-
Xin-zhong Zhang, Ya-jun Lian, Song-feng Chen, Long-xing Xue, and Shi-xing Xue
- Subjects
Cell growth ,Chemistry ,General Neuroscience ,Apoptosis ,Infarction, Middle Cerebral Artery ,medicine.disease ,Mitochondrial Dynamics ,Cell biology ,Brain Ischemia ,Rats ,Receptors, Purinergic P2Y2 ,Phosphatidylinositol 3-Kinases ,mitochondrial fusion ,Reperfusion Injury ,medicine ,Phosphorylation ,Animals ,Mitochondrial fission ,Protein kinase B ,Reperfusion injury ,PI3K/AKT/mTOR pathway - Abstract
P2Y purinoceptor 2 (P2RY2) is involved in the regulation of cell proliferation and apoptosis. The aim of this study was to explore the effects of P2RY2 on cerebral ischemia/reperfusion (I/R) injury and its molecular mechanism. Middle cerebral artery occlusion (MCAO) model in rats and OXYGEN and oxygen-glucose deprivation/reoxygenation (OGD/R) model in PC12 cells were established. P2RY2 expressions in I/R injury model in vitro and in vivo were up-regulated. In the OGD/R group, ROS level, cyto-CytC and mitochondrial fission factors expressions and cell apoptosis were increased, while SOD activity, mito-CytC and mitochondrial fusion factors expressions were decreased. P2RY2 overexpression could reverse these results. Up-regulated P2RY2 expression decreased Yes-associated protein (YAP) phosphorylation level, promote the nuclear translocation of YAP, and inhibit cell apoptosis, which can be reversed by YAP inhibitor verteporfin. The addition of PI3K/AKT inhibitor LY294002 could reverse the decrease of YAP phosphorylation level and cell apoptosis, and the increase of nuclear translocation caused by P2RY2 overexpression. Further in vivo studies validated that interference with P2RY2 increased the cerebral infarction area, decreased AKT expression, enhanced YAP phosphorylation, and inhibited the nuclear translocation of YAP. In conclusion, P2RY2 can alleviate cerebral I/R injury by inhibiting YAP phosphorylation and reducing mitochondrial fission.
- Published
- 2021
9. An experimental investigation in the formation damage mechanism of deposited coke in in-situ combustion process using nuclear magnetic resonance
- Author
-
Wanfen Pu, Bing Wei, Shi-Xing Zhang, Shuai Zhao, Chen Luo, and Yi-Bo Li
- Subjects
Materials science ,General Chemical Engineering ,Organic Chemistry ,technology, industry, and agriculture ,Energy Engineering and Power Technology ,Core (manufacturing) ,Coke ,Combustion ,complex mixtures ,respiratory tract diseases ,chemistry.chemical_compound ,Fuel Technology ,Nuclear magnetic resonance ,Montmorillonite ,chemistry ,Porosity ,Porous medium ,Pyrolysis ,Secondary air injection - Abstract
The success of an in situ combustion process is dependent on the stability and movement of the combustion front. During an in situ combustion process, coke is an important product for maintaining the stability of the combustion front. However, before being consumed by the combustion reaction, coke is deposited in the porous media; thus, it may cause the blockage of the pore throat and affect the subsequent air injection. In this study, the low-field nuclear magnetic resonance technique was applied to examine the influence of oxidized coke and pyrolyzed coke on the porous media. The results revealed that the coke deposition phenomenon was considerable in porous media and affected porosity. The formation damage was considerably severe in oxidized coke because of the drastic low-temperature oxidation. In case of the pyrolyzed core, the influence of coke on porosity is limited because of the low amount of coke generation. The average reduction in porosity was 21.90%, while that of the pyrolyzed coke is only 9.09%. Montmorillonite had the greatest catalytic effect on coke deposition for both oxidation and pyrolysis processes. Illite, kaolinite, and chlorite have an impact on coke deposition; however, because the change in porosity is attribute to a combination of multiple factors, the result is a lack of regularity. Heat causes the pore to reform and the fracture to form. The change in porous media can reduce the impact of coke deposition phenomenon on total porosity. Because of the high-temperature environment, this influence is more pronounced in the pyrolyzed core.
- Published
- 2022
10. Effects of Low-Intensity Pulsed Ultrasound on the Proliferation of Human Umbilical Cord Mesenchymal Stem Cells and Their Chondrogenic Differentiation via Bmp2 /Smad Signaling Pathway
- Author
-
Jin Xuhong, Zeming Zhuo, Che Jiaju, Hejie Wang, Dengao Huang, Chen Xiafu, and Shi Xing
- Subjects
medicine.anatomical_structure ,Chemistry ,Mesenchymal stem cell ,medicine ,SMAD ,Signal transduction ,Low-intensity pulsed ultrasound ,Chondrogenesis ,Umbilical cord ,Bone morphogenetic protein 2 ,Cell biology - Abstract
BackgroundAlthough Low-intensity pulsed ultrasound (LIPUS) regiment has been applied to the treatment of cartilage injury clinically, the effect of LIPUS stress loading on the proliferation and differentiation of hUCMSCs is still controversial. Yet the specific mechanical mechanism of LIPUS stimulates cartilage differentiation of hUCMSCs has not been clarified.ObjectiveTo investigate the effects of low intensity pulsed ultrasound (LIPUS) on proliferation and chondrogenic differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs) via BMP2 /smad signaling pathway in vitro.MethodThe hUCMSCs at P4 were randomly divided into control group(no LIPUS), L30 group (30mW/cm2), L50 group (50mW/cm2), L80 group (80mW/cm2), each LIPUS group respectively loaded 5, 10, 20 min/d, the cell proliferation activity was detected by CCK-8 assay after continuous irradiation for 5 days. For chondrogenic differentiation, hUCMSCs were divided 4 groups as follows: control group, Noggin group, LIPUS group, Noggin+LIPUS group, LIPUS irradiation was given 50w/cm2, 5min/d. Cartilage formation after 3 weeks was evaluated by Alician blue staining for GAG and COL II immunohistochemical staining. Furthermore, RT-PCR analysis of Sox-9, COL II Aggrecan, BMP2, Smad1, Smad5 and Smad9. Result: (1) The proliferation activity of L50 group(50w/cm2 , 5min/d) was noticeably higher compared with other groups, Alcian blue staining of GAG , COL II fluorescent staining in the LIPUS group were much stronger, quantitative RT-PCR assays showed that the expression of COL II, GAG, Sox-9, smad1, smad5 and smad9 in LIPUS group was significantly increased. Conclusion:The suitable LIPUS irradiation can promote cell proliferation, 50mW/cm2 intensity at 5min/d is most significant. And it can promote chondrogenesis of hUCMSCs via upregulating MP2 /smads signaling pathway.
- Published
- 2020
11. Chemical mechanisms of bacterial inactivation using dielectric barrier discharge plasma in atmospheric air
- Author
-
Ma, Yue, Zhang, Guan-Jun, Shi, Xing-Min, Xu, Gui-Min, and Yang, Yun
- Subjects
Plasma physics -- Research ,Electric discharges -- Properties ,Electric discharges through gases -- Properties ,Plasma (Ionized gases) -- Physiological aspects ,Plasma (Ionized gases) -- Properties ,Bacteria -- Observations ,Business ,Chemistry ,Electronics ,Electronics and electrical industries - Abstract
Nonthermal plasma generated by parallel-plate dielectric-barrier discharge with 60-kHz high-voltage power was used to sterilize the bacteria in atmospheric air. Two kinds of typical bacteria, gram-negative E. coli (ATCC8099) and grampositive S. aureus (ATCC6538), were used as test strains. Bacteria cells held by cover-glass were placed on the bottom electrode. By adjusting the applied voltage, gap spacing, and treatment time, the effects of plasma and electric field on bacteria inactivation were investigated. The transmission electron microscope was used to observe the damage of ceils treated by plasma. The concentrations of [K.sup.+], protein, and nucleic acid leaked from cells were measured for detecting the cytoplasm status after plasma treatment. Experimental results showed that almost 100% of S. aureus and E. coli strains were killed in less than 10- and 7-s plasma treatment, respectively. It is concluded that the reactive oxygen species (ROS) in plasma play a dominant role in the inactivation process but not the electric field. It is supposed that the ROS can oxidize the cell membrane and then damage the protein and nucleic acid inside the cells and, thus, kill the bacteria. Index Terms--Bacterial inactivation, dielectric-barrier discharge (DBD), E. coli, reactive oxygen species (ROS), S. aureus.
- Published
- 2008
12. Research on the inactivation effect of low-temperature plasma on Candida albicans
- Author
-
Shi, Xing-Min, Zhang, Guan-Jun, Yuan, Yu-Kang, Ma, Yue, Xu, Gui-Min, and Yang, Yun
- Subjects
Candida albicans -- Properties ,Dielectric devices -- Usage ,Electric discharges -- Health aspects ,Electric discharges through gases -- Health aspects ,Plasma physics -- Research ,Business ,Chemistry ,Electronics ,Electronics and electrical industries - Abstract
A dielectric barrier discharge was used to generate low-temperature plasma to treat Candida albicans. When the gap spacing was 3 nun, the killing log value (KLV) of the plasma on Candida albicans within 20 s of exposure was more than five, and for 4 and 5 nun gap spacing, the KLV within 25 s was more than five. With the extension of exposure time, the decrease in velocity of the number of living Candida albicans was fastest for the gap spacing of 3 mm, and then for 4 and 5 mm spacing. With 60 s of electric field treatment, as the applied voltage increases, the survival number of Candida albicans has no significant difference from that of the control sample. As for the inactivation mechanism of plasma on Candida albicans on the molecular microbiology side, transmission electron microscopic examination and the results of protein, nucleic acid and [K.sup.+] detection in the extracellular environment showed that the plasma destroyed the outer structure of Candida albicans. Cytoplasm was also released, which caused Candida albicans to be dead. On the plasma physics side, the role of the electric field during Candida albicans inactivation by plasma is considered negligible. Therefore, charged particles and reactive species in plasma might play a dominant role in the process of destroying the outer structure of Candida albicans. Index Terms--Candida albicans, dielectric barrier discharge (DBD), low-temperature plasma.
- Published
- 2008
13. Heat shock protein 22 modulates NRF1/TFAM-dependent mitochondrial biogenesis and DRP1-sparked mitochondrial apoptosis through AMPK-PGC1α signaling pathway to alleviate the early brain injury of subarachnoid hemorrhage in rats
- Author
-
Rui Ding, Chengcong Wei, Xin Zhang, Shi-Xing Su, Boyang Wei, Xifeng Li, Haiyan Fan, Wenchao Liu, Chuanzhi Duan, Xuying He, Fa Jin, and Ran Li
- Subjects
0301 basic medicine ,Heat shock protein 22 ,Clinical Biochemistry ,Apoptosis ,AMP-Activated Protein Kinases ,Mitochondrion ,medicine.disease_cause ,Biochemistry ,Neuroprotection ,03 medical and health sciences ,0302 clinical medicine ,Heat shock protein ,medicine ,Animals ,NRF1 ,lcsh:QH301-705.5 ,Heat-Shock Proteins ,lcsh:R5-920 ,Organelle Biogenesis ,Chemistry ,Organic Chemistry ,AMPK ,Subarachnoid Hemorrhage ,TFAM ,Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ,Mitochondria ,Rats ,Cell biology ,030104 developmental biology ,lcsh:Biology (General) ,Mitochondrial biogenesis ,AMPK-PGC1α ,Brain Injuries ,lcsh:Medicine (General) ,030217 neurology & neurosurgery ,Oxidative stress ,Research Paper ,Signal Transduction ,Transcription Factors - Abstract
Mitochondrial dysfunction has been widely accepted as a detrimental factor in subarachnoid hemorrhage (SAH)-induced early brain injury (EBI), which is eminently related to poor neurologic function outcome. Previous studies have revealed that enhancement of heat shock protein 22 (hsp22) under conditions of stress is a friendly mediator of mitochondrial homeostasis, oxidative stress and apoptosis, thus accelerating neurological recovery. However, no study has confirmed whether hsp22 attenuates mitochondrial stress and apoptosis in the setting of SAH-induced EBI. Our results indicated that endogenous hsp22, p-AMPK/AMPK, PGC1α, TFAM, Nrf1 and Drp1 were significantly upregulated in cortical neurons in response to SAH, accompanied by neurologic impairment, brain edema, neuronal degeneration, lower level of mtDNA and ATP, mitochondria-cytosol translocation of cytochrome c, oxidative injury and caspase 3-involved mitochondrial apoptosis. However, exogenous hsp22 maintained neurological function, reduced brain edema, improved oxidative stress and mitochondrial apoptosis, these effects were highly dependent on PGC1α-related mitochondrial biogenesis/fission, as evidenced by co-application of PGC1α siRNA. Furthermore, we demonstrated that blockade of AMPK with dorsomorphin also compromised the neuroprotective actions of hsp22, along with the alterations of PGC1α and its associated pathway molecules. These data revealed that hsp22 exerted neuroprotective effects by salvaging mitochondrial function in an AMPK-PGC1α dependent manner, which modulates TFAM/Nrf1-induced mitochondrial biogenesis with positive feedback and DRP1-triggered mitochondrial apoptosis with negative feedback, further reducing oxidative stress and brain injury. Boosting the biogenesis and repressing excessive fission of mitochondria by hsp22 may be an efficient treatment to relieve SAH-elicited EBI., Graphical abstract The schematic diagram demonstrating that Hsp22 modulates mitochondrial biogenesis and fission through AMPK-PGC1α signaling pathway to alleviate the early brain injury after SAH in rats. SAH subarachnoid hemorrhage, Hsp22 heat shock protein 22, AMPK Adenosine 5'monophosphate-activated protein kinase, PGC1α peroxisome proliferative activated receptor γ (PPARγ) coactivator 1α, Drp1 dynamin-related protein 1, TFAM mitochondrial transcription factor A, Nrf1 nuclear respiratory factor 1, UCP2 uncoupling protein 2, ROS reactive oxygen species, 8-OHdG 8-hydroxyguanine, MDA malondialdehyde, PCO protein carbonyl, Bcl-2 B-cell lymphoma-2, Bax Bcl-2 associated X protein, siRNA small interfering ribonucleic acid.Image 1, Highlights • Hsp22 is notably upregulated in neurons at 24 h after SAH. • Hsp22 boosts the NRF1/TFAM-dependent mitochondrial biogenesis. • Hsp22 represses DRP1-sparked mitochondrial apoptosis. • AMPK-PGC1α pathway is involved in hsp22-mediated neuroprotection after SAH. • Modulation of mitochondrial biogenesis and fission may be efficient for treating SAH.
- Published
- 2021
14. Effects of surface modification of upconversion nanoparticles on cellular uptake and cytotoxicity
- Author
-
Qiao Xin, Zhang Jian, Sun Ying-ying, Tao Youmao, Gu Ye, and Qiao Shi-xing
- Subjects
Aqueous solution ,Biocompatibility ,Ligand ,Polyacrylic acid ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Photon upconversion ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Biophysics ,Surface modification ,Surface charge ,0210 nano-technology - Abstract
Lanthanide-doped upconversion nanoparticles(UCNPs) are great promising to apply to biomedical imaging and therapy. We prepared NaYF4:Yb3+,Er3+ nanoparticles with different surface ligands, i.e., without any ligands(bare), coordinated with 2-aminoethyl dihydrogen phosphate(AEP), polyacrylic acid(PAA) or polyallylamine (PAAm), via a simple two-step ligand exchange of oleic acid capped NaYF4:Yb3+,Er3+ nanoparticles. Although the surface modification retained the crystal structure and transimission electron microscope(TEM) size distribution of the nanoparticles, and good dispersibility in aqueous solution and did not significantly change the upconversion luminescence, distinct differences were observed in the surface charge and hydrodynamic diameter. The cellular uptake and cytotoxicity of the nanoparticles were studied on two different cell lines, breast cancer MCF-7 and fibroblast 3T3. Confocal microscopy images demonstrate that PAAm-coordinated UCNPs can enhance the cellular uptake and endocytosis, whereas AEP- and PAA-coordinated UCNPs show a very low level of nonspecific adsorption. Biocompatibility studies based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay, however, indicate that PAAm-coordinated UCNPs are more toxic than the other two, and thus need further modifiaction(like PEG coordinating) to improve their biocompatibility. These results are important to the knowledge base required for the biomedical application of the UCNPs.
- Published
- 2016
15. Agricultural production efficiency and spatial pattern under carbon emission constraint: Based on 65 villages of Henan province
- Author
-
Rongqin Zhao, Qing-lin Yang, Ruiming Zhu, Xiao-wei Chuai, Liangang Xiao, Jiao Yu, Shi-xing Jiao, Wen-juan Yang, and Shuai Wang
- Subjects
Constraint (information theory) ,chemistry ,Common spatial pattern ,chemistry.chemical_element ,Environmental science ,Agricultural engineering ,Agricultural productivity ,Carbon - Published
- 2020
16. Protein kinase C inhibitor chelerythrine attenuates partial unilateral ureteral obstruction induced kidney injury in neonatal rats
- Author
-
Shi-Xing Li, Xin Liu, Bo Shi, Dan Li, Hao Ju, and Ying Li
- Subjects
0301 basic medicine ,medicine.medical_specialty ,medicine.medical_treatment ,Intraperitoneal injection ,Kidney Glomerulus ,Renal function ,Apoptosis ,urologic and male genital diseases ,Kidney ,030226 pharmacology & pharmacy ,General Biochemistry, Genetics and Molecular Biology ,Rats, Sprague-Dawley ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Fibrosis ,Internal medicine ,medicine ,Renal fibrosis ,Animals ,General Pharmacology, Toxicology and Pharmaceutics ,Protein Kinase Inhibitors ,Protein kinase C ,Protein Kinase C ,Benzophenanthridines ,integumentary system ,urogenital system ,General Medicine ,medicine.disease ,Obstructive Nephropathy ,Rats ,Disease Models, Animal ,030104 developmental biology ,Endocrinology ,Chelerythrine ,medicine.anatomical_structure ,Kidney Tubules ,chemistry ,Animals, Newborn ,Kidney Diseases ,Ureteral Obstruction - Abstract
The present study aimed to evaluate the renoprotective effects of chelerythrine (CHE), a protein kinase C inhibitor, on neonatal rats after partial unilateral ureteral obstruction (UUO) surgery. New born Sprague Dawley rats were subjected to partial UUO 48 h after birth and received a daily intraperitoneal injection of 5 mg/kg CHE. At 21-day age, the rats were scarified and the kidneys were collected for analysis. Results showed that CHE treatment significantly increased kidney weight and restored renal function in the obstructed kidney. Histological examination demonstrated that CHE attenuated renal injury by reducing renal parenchymal loss and preventing glomerular and tubular degeneration. In addition, CHE inhibited partial UUO-induced upregulated kidney injury molecule-1 expression and apoptosis and renal fibrosis. Moreover, as a PKC inhibitor, CHE significantly inhibited PKCα and PKCβ membrane translocation. This action may be associated with its effects of anti-apoptosis and anti-fibrosis and contribute to the renoprotection. This short-term study suggests that CHE is beneficial for obstructive nephropathy in neonatal rats and provides foundation for further studies to reveal the long-term effects of CHE on obstructive nephropathy in children and infants.
- Published
- 2018
17. Inhibition of MiRNA-125b Decreases Cerebral Ischemia/Reperfusion Injury by Targeting CK2α/NADPH Oxidase Signaling
- Author
-
Song-Lin Yang, Jia-Yu Tang, Xiao-Juan Li, Shi-Xing Wu, Yu Wang, Jing Xu, Yong Liang, and Hong-Guang Xiang
- Subjects
Male ,CK2α ,Physiology ,Oxygen-glucose deprivation and reoxygenation (OGD/R) ,Ischemia ,Down-Regulation ,Apoptosis ,PC12 Cells ,lcsh:Physiology ,lcsh:Biochemistry ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,microRNA ,medicine ,NADPH ,Animals ,lcsh:QD415-436 ,Casein Kinase II ,MiRNA-125b ,NADPH oxidase ,biology ,lcsh:QP1-981 ,L-Lactate Dehydrogenase ,Chemistry ,Caspase 3 ,Antagomirs ,NADPH Oxidases ,medicine.disease ,Cell Hypoxia ,Cell biology ,Rats ,Disease Models, Animal ,MicroRNAs ,030220 oncology & carcinogenesis ,Reperfusion Injury ,biology.protein ,Ischemia–reperfusion (I/R) ,MiRNAs ,Reactive Oxygen Species ,Reperfusion injury ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
Background/Aims: Cerebral ischemia-reperfusion (I/R) injury involves multiple independently fatal terminal pathways. CK2α/NADPH oxidase is an important signaling pathway associated with ischemia-reperfusion injury, and miR-125b can regulate oxidative stress-related injury. In this study, we investigated whether the effect of miR-125b in rat brain I/R injury occurs through its modulation of the CK2α/NADPH oxidase pathway. Methods: Rats were subjected to 2 h of cerebral ischemia followed by 24 h of reperfusion to establish an I/R injury model. Neurological deficit was evaluated using a five-point score. Infarct volume was evaluated with 2, 3, 5-triphenyltetrazolium chloride (TTC) staining, and RT-PCR was used to detect expressions of miR125b and CK2α. We then examined the association between miR-125b expression and the CK2α/NADPH oxidative signaling pathway in a PC-12 cell oxygen-glucose deprivation and reoxygenation (OGD/R) injury model. Transfection with miR-125b mimics, an miR-125b inhibitor, and luciferase reporter gene plasmid was accomplished using commercial kits. In these cells, Western blots were used to detect the levels of expression of CK2α, cleaved caspase-3, NOX2, and NOX4. RT-PCR was used to detect the expressions of CK2α, miR125b, NOX2, and NOX4. We evaluated Lactate Dehydrogenase (LDH) level, NADPH oxidase activity, and caspase-3 activity using commercial kits. Mitochondrial reactive oxygen species (ROS) were measured by fluorescence microscopy. For both PC-12 cells and rat brains, histological analyses were conducted to observe morphological changes, and apoptosis was measured using a commercial kit. Results: I/R rats exhibited an increase in neurological deficit score, infarct volume, and cellular apoptosis, along with miR-125b elevation and CK2α downregulation. OGD/R treatment increased PC-12 cells’ injuries, cellular apoptosis, and ROS levels. These changes were associated with miR-125b elevation, CK2α downregulation and activations of NOX2 and NOX4, mimicking our in vivo findings. All of these effects were reversed by the inhibition of miR-125b, confirming a strong correlation between miR-125b activity and the CK2α/NADPH oxidase signaling pathway. Conclusions: Based on these observations, we conclude that inhibition of miR-125b protects the rat brain from I/R injury by regulating the CK2α/NADPH oxidative signaling pathway.
- Published
- 2017
18. Ulinastatin suppresses endoplasmic reticulum stress and apoptosis in the hippocampus of rats with acute paraquat poisoning
- Author
-
Bao-peng Xing, Mingli Sun, Haifeng Li, and shi-xing zhao
- Subjects
hippocampus ,paraquat ,sciatic nerve ,Pharmacology ,SMAD3 ,real-time quantitative PCR ,heterocyclic compounds ,NSFC grant ,neural stem cells ,reactive oxygen species ,dextromethorphan ,ulinastatin ,transforming growth factor β1 ,lipid peroxidation ,task difficulty ,spiral ganglion cells ,diffusion tensor imaging ,gene therapy ,electroacupuncture therapy ,trauma ,ototoxicity ,superparamagnetic iron oxide ,apparent diffusion coefficient ,nanocarrier ,neuroprotection ,DAPT ,neural regeneration ,malondialdehyde ,medicine.medical_specialty ,laser photocoagulation ,notch signaling pathway ,proliferation ,Chinese herbal formula ,Caspase 3 ,Brain damage ,Neuroprotection ,cell transplantation ,Cell damage ,JNK3 ,cerebral hemorrhage ,Notch1 ,astrocytes ,Xuesai Tong ,spinal cord ,survival curve ,Ulinastatin ,medicine.disease ,poisoning ,glaucoma ,chemistry ,Apoptosis ,regeneration ,magnetic guidance ,Src kinase ,transcranial direct current stimulation ,intraocular pressure ,caspase-3 ,type 1 diabetes ,cochlea ,microglia ,cisplatin ,neurons ,cerebral ischemia ,lcsh:RC346-429 ,neuroinflammation ,rosiglitazone ,chemistry.chemical_compound ,Paraquat ,visuomotor coordination ,primary motor area ,magnetic resonance imaging ,dentate gyrus ,retinal ganglion cell ,ongluo Jiunao injection ,nerve regeneration ,X-linked inhibitor of apoptosis protein ,tamoxifen ,Tneurotrophic factor ,auranofin ,neurodegeneration ,average combined score ,apoptosis ,differentiation ,PP2 ,spinal cord transection ,immunohistochemistry ,Evans blue tracer ,endoplasmic reticulum stress ,medicine.symptom ,hypothermia ,fractional anisotropy ,blood-nerve barrier ,acupuncture ,Research Article ,GRP78 ,Lung injury ,fiber tractography ,Developmental Neuroscience ,medicine ,lumbar puncture ,peripheral nerve injury ,neural degeneration ,lcsh:Neurology. Diseases of the nervous system ,magnetic resonance image ,business.industry ,nerve growth factor receptor ,bone marrow mesenchymal stem cells ,polyethyleneimine-polyethylene glycol ,brain injury ,spinal cord injury ,Surgery ,Hes1 ,rats ,Alzheimer′s disease ,inflammation ,ocular hypertension ,business ,motor learning ,CHOP ,western blot assay - Abstract
Lung injury is the main manifestation of paraquat poisoning. Few studies have addressed brain damage after paraquat poisoning. Ulinastatin is a protease inhibitor that can effectively stabilize lysosomal membranes, prevent cell damage, and reduce the production of free radicals. This study assumed that ulinastatin would exert these effects on brain tissues that had been poisoned with paraquat. Rat models of paraquat poisoning were intraperitoneally injected with ulinastatin. Simultaneously, rats in the control group were administered normal saline. Hematoxylin-eosin staining showed that most hippocampal cells were contracted and nucleoli had disappeared in the paraquat group. Fewer cells in the hippocampus were concentrated and nucleoli had disappeared in the ulinastatin group. Western blot assay showed that expressions of GRP78 and cleaved-caspase-3 were significantly lower in the ulinastatin group than in the paraquat group. Immunohistochemical findings showed that CHOP immunoreactivity was significantly lower in the ulinastatin group than in the paraquat group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining showed that the number of apoptotic cells was reduced in the paraquat and ulinastatin groups. These data confirmed that endoplasmic reticular stress can be induced by acute paraquat poisoning. Ulinastatin can effectively inhibit this stress as well as cell apoptosis, thereby exerting a neuroprotective effect.
- Published
- 2015
19. Selective removal of heavy metal ions from aqueous solutions with surface functionalized silica nanoparticles by different functional groups
- Author
-
Shengguo Xue, Kong Xiangfeng, Yang Zhou, Bin Yang, Shi-xing Wang, Heng Xiong, and Baoqiang Xu
- Subjects
Materials science ,Aqueous solution ,Silica fume ,Metal ions in aqueous solution ,Inorganic chemistry ,Metals and Alloys ,General Engineering ,chemistry.chemical_compound ,Adsorption ,chemistry ,Selective adsorption ,Triethoxysilane ,Surface modification ,Nuclear chemistry ,Hydrophobic silica - Abstract
The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as (3-Mercaptopropyl) triethoxysilane (MPTES) and (3-Amincpropyl) trithoxysilane (APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared (FI-IR) and X-ray photoelectron spectroscopy (XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ ions in aqueous solutions. The results show that the (3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles (SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the (3-Amincpropyl) trithoxysilane (APTES) functionalized silica nanoparticles (SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.
- Published
- 2014
20. Influence of Overburning on Microstructure and Property of 2024 Aluminum Alloy
- Author
-
Shi Xing Zhang, Gang Yi Cai, and Yu Ping Zhu
- Subjects
Materials science ,Metallurgy ,Alloy ,General Engineering ,chemistry.chemical_element ,Solution treatment ,engineering.material ,Microstructure ,Indentation hardness ,Microanalysis ,chemistry ,Aluminium ,Vickers hardness test ,engineering ,Grain boundary - Abstract
Process of solution treatment of 2024 aluminum alloy was done by hardness test and microanalysis in this paper. The effects of different solution treatment temperature on the microstructure and mechanical properties of 2024 aluminum alloy were studied and the influence of overburning on the microstructure and mechanical properties of 2024 aluminum alloy were also analyzed. The experimental results show that overburning occurs while 2024 aluminum alloy is heated over 490°C×50min . The hardness tests and microstructure analysis results show that the hardness decreased, grain boundary becomes trigemanal and compounded –melting structure (burnt structure) appeared when overburning occuring for this alloy .
- Published
- 2014
21. Research of Micro-Inertial Device High-Aspect-Ratio Etching Parameters
- Author
-
Gui Xiong Shi, Guo Qin Jiang, Jian Zhu, and Shi Xing Jia
- Subjects
Microelectromechanical systems ,Materials science ,Passivation ,Silicon ,business.industry ,Mechanical Engineering ,chemistry.chemical_element ,Nanotechnology ,Isotropic etching ,chemistry ,Mechanics of Materials ,Deep reactive-ion etching ,Optoelectronics ,General Materials Science ,Dry etching ,Reactive-ion etching ,business ,Buffered oxide etch - Abstract
This is mainly due to the high chemical reactivity and spontaneous etching nature of the fluorine radicals towards silicon, and the high volatility of the silicon fluorides as reaction products. Anisotropy can only be achieved by the inclusion of sidewall passivation schemes to the process. The existing approaches to deep reactive ion etching (DRIE) of silicon are distinguished by the way sidewall passivation is achieved, the key to anisotropy and overall performance of the etch process. Cryogenic etching and the so-called Bosch process with alternating etch and passivation cycles are the two most well-known high-aspect-ratio silicon etch processes and are discussed in this paper.
- Published
- 2014
22. Structural and Dielectric Properties of XBaZr0.2Ti0.8O3-(1-x)BiFeO3 Solid Solution Ceramics
- Author
-
Xiao Ling Deng, Wei Cai, Gang Chen, Chun Lin Fu, and Shi Xing Zhong
- Subjects
Materials science ,Mechanical Engineering ,Mineralogy ,Dielectric ,Atmospheric temperature range ,Condensed Matter Physics ,Titanate ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Dielectric loss ,Ceramic ,Composite material ,Leakage (electronics) ,Bismuth ferrite ,Solid solution - Abstract
xBaZr0.2Ti0.8O3-(1-x)BiFeO3(x=0, 0.3, 0.5, 0.7) solid solution ceramics were prepared by conventional solid-state reaction method. The crystal structure and dielectric properties ofxBaZr0.2Ti0.8O3-(1-x)BiFeO3ceramics have been investigated. The result indicates that the crystal structure of solid solution ceramics changes from rhobohedral to pseudocubic structure with the increase of barium zirconate titanate content. The room temperature dielectric constant of all samples decreases with the increasing of frequency. When the temperature is in the range of 30oC~150oC, the dielectric constant of all samples increases as temperature rises. In the same temperature range, the dielectric loss of BiFeO3ceramics increases with the rise of temperature and the dielectric loss ofxBaZr0.2Ti0.8O3-(1-x)BiFeO3(x=0.3~0.7) changes a little. The addition of barium zirconate titanate leads to the decrease of dielectric loss and leakage current for BiFeO3ceramics.
- Published
- 2014
23. Study on MEMS Capacitive Differential Pressure Sensor
- Author
-
Zhi Hao Hou, Shi Xing Jia, and Zhen Huang
- Subjects
Microelectromechanical systems ,Materials science ,Silicon ,business.industry ,Mechanical Engineering ,Capacitive sensing ,Analytical chemistry ,chemistry.chemical_element ,Capacitive displacement sensor ,Pressure sensor ,Capacitance ,chemistry ,Mechanics of Materials ,Anodic bonding ,Electrode ,Optoelectronics ,General Materials Science ,business - Abstract
The design and fabrication of MEMS capacitive differential pressure sensor is reported. Silicon membrane is used as movable electrode. Gold metal film on glass is used as fixed electrode. Anodic bonding is used to bond together the silicon and glass to form the capacitive pressure sensor. The measurement capacitance of the sensors is 5.37 pF at an applied pressure of 0 kPa and 7.26 pF and the full operating range of 40 kPa.The ratio of changed to initial capacitance was 0.35. The error of the MEMS capacitive pressure sensor is less than 4‰ full-scale(FS) by using quadratic curve fitting which can meet most application requirements.
- Published
- 2014
24. [Untitled]
- Author
-
Hai-Feng Li, Xiao-Liang Liu, Yan-Ping Wu, shi-xing zhao, and Ming-Li Sun
- Subjects
chemistry.chemical_compound ,Chromatography ,chemistry ,business.industry ,medicine.medical_treatment ,Hemofiltration ,medicine ,Critical Care and Intensive Care Medicine ,Hemoperfusion ,business ,Butyl acetate - Published
- 2012
25. Effects of Deformation Ratio above Recrystallizaton Temperature on Microstructure and Properties of 2A12 Aluminum Alloy
- Author
-
Yu Ping Zhu, Gang Yi Cai, and Shi Xing Zhang
- Subjects
Microscope ,Materials science ,Metallurgy ,Alloy ,Recrystallization (metallurgy) ,chemistry.chemical_element ,General Medicine ,engineering.material ,Microstructure ,law.invention ,chemistry ,law ,Homogeneous ,Aluminium ,engineering ,Metallography ,Softening - Abstract
The thermomechanical treatment of a 2A12 aluminum alloy was researched and the influence of deformation ratio above recrystallization temperature on microstructure and hardness was analyzed emphatically. The result reveals that when the deformation ratio is low at first, the hardness of specimen decreased because the effect of recrystallization softening overwhelms the effect of deformation strengthening. However, hardness increased with increasing deformation ratio. In addition, the microstructure became more homogeneous and grains were refined obviously by metallography microscope observation with increasing deformation ratio. The second phase precipitates dispersedly to strengthen the alloy.
- Published
- 2012
26. Effects of Pre-Ageing on Thermomechanical Treatment Process of 2A12 Aluminum Alloy
- Author
-
Hai Hong Wu, Yu Ping Zhu, and Shi Xing Zhang
- Subjects
Equiaxed crystals ,Materials science ,Alloy ,Metallurgy ,chemistry.chemical_element ,General Medicine ,engineering.material ,Microstructure ,Hardness ,Indentation hardness ,chemistry ,Aluminium ,Ageing ,Phase (matter) ,engineering - Abstract
The thermomechanical treatment of a 2A12 aluminum alloy was researched and the influence of pre-ageing on microstructure and hardness was analyzed emphatically. The results reveal that the hardness of specimen increases when they are pre-aged, the hardness value rises at first and then decreases, reaching the maxmum value when pre-aged at 180°C×30min . After plastically deformed at 450°C, the hardness keeps on increasing, and the grains are equiaxed polygon structure. After all the workpieces are aged in the end, the small particles of the second phase precipitates completely and disperses within the original phase matrix, the particles interact with dislocations in upper state that formed during plastic deformation and lead to a great increase in hardness compared with as-received. the best pre-aging parameter is 180°C×30min.
- Published
- 2012
27. Development of a micro-graphite impregnated grinding wheel
- Author
-
Ming-Yi Tsai and Shi-Xing Jian
- Subjects
Materials science ,Hydrogen ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,Grinding wheel ,Industrial and Manufacturing Engineering ,Grinding ,Coolant ,Wheel wear ,chemistry ,Lubrication ,Surface roughness ,Graphite - Abstract
This paper introduces a newly designed grinding wheel where micro-graphite particles are impregnated in an aluminum oxide matrix to form a grinding wheel to lubricate the grinding site; these are known as graphite-impregnated grinding wheels. The graphite particles were heat-treated under a layer of hydrogen ions at a temperature of about 500 °C for 30 min to disperse them uniformly in the aluminum oxide matrix. In this study, grinding wheels with five different graphite contents (0.1, 0.5, 1, 3, and 5 wt%) were investigated. Different aspects of the grinding performance (e.g., surface roughness, morphology, wheel wear ratio, grinding temperature, and grinding forces) using these grinding wheels under two different coolant strategies (dry and minimum quantity lubrication with pure water) were compared with the corresponding values for a conventional grinding wheel. The experimental results indicate that using graphite-impregnated grinding wheels considerably improves the grinding process performance compared to using a conventional grinding wheel. A graphite content of below 0.5 wt% is recommended because this provides not only better surface roughness and topography, and lower grinding temperature and force but also less grinding wheel consumption; hence, the wheel life was extended. In summary, combining graphite-impregnated grinding wheels with minimum-quantity lubrication technology has the potential to effectively eliminate the use of any oils or toxic organic lubricants in the grinding process.
- Published
- 2012
28. A Highly Sensitive and Efficient Functionalized Magnetic Chemosensor for Cu2+ Removal
- Author
-
Yang Zhou, Xiangfeng Kong, Shi-xing Wang, Yuxiang Chen, and Zaixiang Yang
- Subjects
chemosensor ,Materials science ,Aqueous solution ,Cu2+ removal ,Physics and Astronomy(all) ,Highly sensitive ,chemistry.chemical_compound ,symbols.namesake ,Fourier transform ,chemistry ,X-ray photoelectron spectroscopy ,Covalent bond ,symbols ,functionalization ,Surface modification ,Fe3O4 nanoparticles ,Fe3o4 nanoparticles ,Acetamide ,Nuclear chemistry - Abstract
Fe3O4 nanoparticles were covalently functionalized by N-(quinoline-8-yl)-2-(3-triethoxysilyl-propylamino)- acetamide (QTPA), and finally utilized to be magnetic chemosensor for sensitive and efficient Cu2+ removal in aqueous solution. Fourier FT-IR, TEM, XRD and XPS results showed that QTPA was bonded to the surface of Fe3O4 nanoparticles. At room temperature, the magnetic chemosensor exhibited high removal efficiency towards Cu2+.
- Published
- 2012
29. Effects of Thermomechanical Treatment Process on the Microstructure and Properties of 7A04 Aluminum Alloy
- Author
-
Shi Xing Zhang, Gang Yi Cai, and Hai Hong Wu
- Subjects
6111 aluminium alloy ,Materials science ,Alloy ,Metallurgy ,technology, industry, and agriculture ,General Engineering ,chemistry.chemical_element ,Deformation (meteorology) ,engineering.material ,Microstructure ,chemistry ,Ageing ,Aluminium ,Phase (matter) ,engineering ,Metallography - Abstract
The mechanical properties of Al-Zn-Mg aluminum alloy were improved by deformation strengthening and transformations strengthening adopting thermomechanical treatment, whose process are solution treatment, preageing treatment, deformation treatment and ageing treatment in turn. The paper focuses on the influences of deforming degree and ageing process on microstructure and properties of Al-Zn-Mg aluminum alloy. The experimental results show that hardness increased with increasing deformation ratio, and the value are greatly higher than that of samples after solution treatment. The results of ageing after deformation show that the hardness enhanced with prolonging the ageing time, which reach the peak value at 16 hours. In addition, the microstructure became more homogeneous and the grain was refined obviously by metallography microscope observation. The second phase precipitate dispersedly to strengthen the alloy. Above all, in order to obtain the better mechanical properties, the optimal thermomechanical treatment processes are solution treatment at 470°C for 2h, preageing treatment at 140°C for 24h, deformation with ratio of 40% as well as ageing at 120°C for 16h.
- Published
- 2011
30. Effects of Solution and Two-Stage Ageing Treatment Process on Microstructure and Properties of 6061 Aluminum Alloy
- Author
-
Gang Yi Cai, Hai Hong Wu, and Shi Xing Zhang
- Subjects
6111 aluminium alloy ,Materials science ,Metallurgy ,Alloy ,General Engineering ,chemistry.chemical_element ,engineering.material ,Microstructure ,Alonizing ,chemistry ,Aluminium ,Ageing ,Phase (matter) ,engineering ,Grain boundary - Abstract
Comprehensive performance of 6061 aluminum alloy was improved by solution treatment and two-step ageing treatment in this paper . The effects of different thermal processing parameters on the microstructure and mechanical properties of 6061 aluminum alloy were studied. The experimental results show that the optimal process of solution treatment for 6061 aluminum alloy is heated at 500°C for 10min. After first-stage aging, the hardness measurements and microstructure analysis results show that the hardness increased with increasing aging temperature, and reached peak value at temperature 180°C for 10h, while in the second-stage ageing treatment, the sample got the ageing peak value at 220°C for 1h. After two-stage treatment, the grains of 6061 aluminum alloy became uniform and fine and the second phase distributed along the grain boundary and play an important role of dispersion strengthening. Above all, the optimal heat treatment process of 6061 aluminum alloy is solution treated at 500°C for 10min, as well as ageing at 180°C, 10h and 220°C, 1h
- Published
- 2011
31. Lateral RF MEMS Switch Based on Surface Micromachining Process
- Author
-
Yuan Wei Yu, Shi Xing Jia, Li Li Jiang, Jian Zhu, and Guo Ping Du
- Subjects
Microelectromechanical systems ,Resistive touchscreen ,Materials science ,Silicon ,business.industry ,Mechanical Engineering ,Electrical engineering ,chemistry.chemical_element ,Substrate (electronics) ,Surface micromachining ,chemistry ,Mechanics of Materials ,Return loss ,Optoelectronics ,Insertion loss ,General Materials Science ,business ,Contact area - Abstract
In this paper, a novel RF MEMS switch driven by combs with low insertion loss is presented. The developed SPST RF MEMS switch with a lateral resistive contact and gold structure layer on a silicon substrate has been fabricated by surface micromachining process. The RF performance of the switch indicates an insertion loss below 0.30 dB at 20 GHz, a return loss better than 20 dB and isolation greater than 30 dB. Good RF characteristics have been achieved by the large contact area and a lateral Au-to-Au resistive contact.
- Published
- 2011
32. Functionalized Silica Fume for Chromium (VI) Removal from Wasterwater
- Author
-
Shi Xing Wang, Yong Nian Dai, Yang Zhou, Wen Hui Ma, and Ke Qiang Xie
- Subjects
Sorbent ,Materials science ,Silica fume ,Mechanical Engineering ,technology, industry, and agriculture ,chemistry.chemical_element ,Condensed Matter Physics ,law.invention ,chemistry.chemical_compound ,Chromium ,Adsorption ,chemistry ,Mechanics of Materials ,law ,Polyaniline ,otorhinolaryngologic diseases ,Surface modification ,Organic chemistry ,General Materials Science ,Atomic absorption spectroscopy ,Tem analysis ,Nuclear chemistry - Abstract
Chemical modified silica fume by polyaniline was studied as a sorbent for removal of chromium (VI) determined by flame atomic absorption spectrometer. TEM analysis confirmed that the mean diameter of silica fume before and after treatment was of the order of 120 nm. The functionalized nanoparticles showed an extremely high efficiency towards chromium (VI) in the pH range of 4-5. Adsorption of chromium (VI) from water using functionalized silica fume was both a simple and efficient approach compared to the traditional adsorbents from the angle of integrated utilization of the secondary resources.
- Published
- 2011
33. Epitaxial Growth of Trichosanthin Protein Crystals on Mica Surface
- Author
-
Sheng(黄胜) Huang, Jian(李健) Li, Huan Zhou, Shi-Xing(陶世兴) Tao, Jun(胡钧) Hu, Jian-Hua(何建华) He, Chun-Yan(徐春艳) Xu, Lihua(孙丽华) Sun, Feng(郁峰) Yu, and Lin(唐琳) Tang
- Subjects
Chemistry ,fungi ,Nucleation ,Crystal growth ,General Chemistry ,Crystal structure ,Condensed Matter Physics ,Epitaxy ,Crystal ,stomatognathic diseases ,Crystallography ,X-ray crystallography ,General Materials Science ,Mica ,Protein crystallization - Abstract
We report the studies of epitaxial growth of trichosanthin (TCS) crystals on a mica substrate. TCS crystals grown on mica surface are found to be aligned well in four orientations, which was induced by the lattice of the mica substrate. The effect of potassium ions both at the mica surface and in solution was investigated by using different cation-modified surfaces and different precipitants. The results indicated that the binding of K+ ions on the mica surface played a critical role in the epitaxial crystal growth of TCS. The high-resolution structures of crystals grown in different precipitants were solved by synchrotron radiation X-ray crystallography, and the K+ binding sites in TCS crystals were identified. A strict lattice match between the TCS crystal and the mica substrate has been demonstrated based on the structural analysis of them. It reveals the mechanism of epitaxial nucleation and growth of TCS crystals. The experimental results provide new insights into the molecular mechanism of epitaxial...
- Published
- 2010
34. Fabrication of Nanomechanical Resonators in Silicon Nitride
- Author
-
Mei Liu, Shi Xing Jia, Jian Zhu, Quan Cheng Gong, Min Zhuo, and Le Lu
- Subjects
Fabrication ,Materials science ,General Engineering ,Nanotechnology ,law.invention ,chemistry.chemical_compound ,Resonator ,Silicon nitride ,chemistry ,law ,Electrode ,X-ray lithography ,Reactive-ion etching ,Photolithography ,Lithography - Abstract
We report our efforts towards fabricating nanomechanical resonators patterned by optical lithography in silicon nitride. Optical lithography has advantages of low cost and high efficiency over electron-beam lithography. Double clamped beam resonators with thickness 150nm, length and lateral dimensions 20um, 800nm have been designed. Through utilizing reactive ion etching and controlling gas flow, reaction time of CF4 and O2 plasma and power of the upper and lower electrode, nanomechanical resonators with lateral dimensions within 200nm are demonstrated.
- Published
- 2009
35. Investigation on Fine Polishing Technique of Silicon Wafer
- Author
-
Shi Xing Jia, Quan Cheng Gong, Jian Zhu, and Jing Wu
- Subjects
Engineering drawing ,Materials science ,Silicon ,General Engineering ,chemistry.chemical_element ,Polishing ,Surface finish ,Lapping ,chemistry ,Chemical-mechanical planarization ,Surface roughness ,Wafer ,Composite material ,Layer (electronics) - Abstract
This paper presents a kind of fine polishing technique that adopts three-step polishing procedure and keeping-wafer-wet method. In order to remove the damaged layer created by lapping process or improve surface condition of silicon wafer, polishing process is needed. In this paper, techniques of improving the surface roughness of silicon are studied, three different polishing processes are presented, and optimum condition has been attained. Experiments of Si-Si bonding are also performed, and results show that after polishing ends, keeping surface of wafer wet is necessary to avoid slurry agglomerating.
- Published
- 2009
36. Determination of Chitosan in Serum Albumin-Cu(II)-Chitosan Ternary System Using Resonance Rayleigh Scattering Spectra
- Author
-
Zhou Shang, Yang Ji-dong, and Deng Shi-xing
- Subjects
Detection limit ,Ternary numeral system ,biology ,Chemistry ,Analytical chemistry ,Buffer solution ,Human serum albumin ,Analytical Chemistry ,Chitosan ,chemistry.chemical_compound ,medicine ,biology.protein ,Bovine serum albumin ,Selectivity ,Ternary complex ,medicine.drug - Abstract
In Britton-Robinson (B-R) buffer solution (pH 6.5), serum album (SA) and chitosan reacted with each other, and the resonance Rayleigh scattering (RRS) spectrum of the system seemed to be very weak. After adding Cu 2+ to make the concentration ratio of Cu 2+ to SA being 10:1, which would react to form a ternary complex, its RRS intensity was significantly enhanced. The enhanced intensity of RRS was directly proportional to the concentration of chitosan. In this study, the reaction conditions and the formation mechanism of the ternary complex of BSA (or HSA) with Cu 2+ and chitosan were studied. The maximum RRS wavelengths are observed at 350 nm and 480 nm for BSA system, and at 340 nm for HSA system. The linear ranges and the detection limits are 0.01–4.0 g ml –1 and 3.66 ng ml –1 for BSA system, and 0.01–6.0 g ml –1 and 11.0 ng ml –1 for HSA. The RSD is less than 4.0%. It is obvious that the BSA system has a higher sensibility. So, a sensitive, simple, and fast method for the determination of trace amounts of chitosan by RRS technique has been developed. The influences of coexisting substances were investigated, and it is shown that the method has a good selectivity. This method has been applied for the determination of chitosan in hygienical capsule samples and self-made chitosan raw samples, and satisfactory results have been obtained.
- Published
- 2007
37. Fluorescence quenching of serum albumin by rifamycin antibiotics and their analytical application
- Author
-
Zhongfang Liu, Ling Kong, Shi-Xing Deng, Jidong Yang, and Shaopu Liu
- Subjects
Reaction mechanism ,Binding Sites ,Chromatography ,Quenching (fluorescence) ,biology ,Chemistry ,Biophysics ,Albumin ,Serum albumin ,Rifamycin ,Human serum albumin ,Rifamycins ,Anti-Bacterial Agents ,Spectrometry, Fluorescence ,Energy Transfer ,Chemistry (miscellaneous) ,biology.protein ,medicine ,Animals ,Humans ,Cattle ,Bovine serum albumin ,Selectivity ,Serum Albumin ,medicine.drug - Abstract
In neutral medium, rifamycin antibiotics such as rifapentin (RFPT), rifampicin (RFP), rifandin (RFD) and rifamycin SV (RFSV) can bind with human serum albumin (HSA) and bovine serum albumin (BSA) to form complexes, resulting in the quenching of the intrinsic fluorescence (λex/λem = 285/355 nm) of the BSA and HSA. The quenching intensity (ΔF) is directly proportional to the concentration of the rifamycin antibiotics. Therefore, a new analytical method was established to determine trace rifamycin antibiotics. The method had fairly high sensitivity and the detecting limits (3σ) for RFPT, RFP, RFD and RFSV were 0.85, 0.98, 1.83, 1.89 ng/mL, respectively, for the HSA system and 0.76, 0.89, 1.55, 1.77 ng/mL, respectively, for the BSA system. All relative standard deviations (RSDs) were
- Published
- 2007
38. Fabrication of silicon-based two-dimensional photonic crystals
- Author
-
Jianfeng Gao, Bailing Zhou, Jian Zhu, Yong Zhang, and Shi-Xing Jia
- Subjects
Materials science ,Silicon ,Physics::Instrumentation and Detectors ,business.industry ,Hybrid silicon laser ,Physics::Optics ,chemistry.chemical_element ,Substrate (electronics) ,Condensed Matter Physics ,Computer Science::Other ,Electronic, Optical and Magnetic Materials ,Lattice constant ,Optics ,chemistry ,Hardware and Architecture ,Etching (microfabrication) ,Hexagonal lattice ,Electrical and Electronic Engineering ,business ,Electron-beam lithography ,Photonic crystal - Abstract
Both triangular lattice and square lattice photonic crystals with lattice constant 400 nm and the radius 200 nm of the air pores in the silicon substrate have been designed, fabricated and realized. The processes of the fabrication of the two-dimensional photonic crystals, based on silicon, including mask making, electron-beam lithography, and inductively coupled plasma etching are introduced.
- Published
- 2006
39. Effects of the aspect ratio on the sedimentation of a fiber in Newtonian fluids
- Author
-
Lin Jianzhong, You Zhenjiang, and Shi Xing
- Subjects
Fluid Flow and Transfer Processes ,Atmospheric Science ,Environmental Engineering ,business.industry ,Sedimentation (water treatment) ,Chemistry ,Mechanical Engineering ,Lattice Boltzmann methods ,Reynolds number ,Mechanics ,Pollution ,Aspect ratio (image) ,symbols.namesake ,Optics ,Orientation (geometry) ,Newtonian fluid ,symbols ,Fiber ,A fibers ,business - Abstract
Lattice Boltzmann method is used to investigate sedimentation of a single fiber in a Newtonian fluid. The effects of the aspect ratio of a fiber are carefully examined. The computational results show that the stable orientation of a single fiber is the horizontal direction. The terminal Reynolds number increases as the aspect ratio increases, and basically remains invariable when the aspect ratio is high enough. The lateral drift of the fiber is more apparent at higher aspect ratios and the orientation of the fiber at which the lateral drifting velocity reaches the maximal is not sensitive to the value of the aspect ratio. When the aspect ratio is around 2.8, the fiber rotates fastest from the vertical location to the horizontal. Some of the results are compared with the experimental data and good agreements are found.
- Published
- 2003
40. Cross-talk of the related bioactivity mediators in serum after injection of soluble TNF-α receptor on silicosis model of rats
- Author
-
Hongsheng Gao, Zhen Yang, Peng Ding, Shi-Xing Wang, Nan-Fang Chen, Rong Xue, Bing Meng, and Huabing Zhao
- Subjects
Male ,medicine.medical_specialty ,Health, Toxicology and Mutagenesis ,Interleukin-1beta ,Silicosis ,Enzyme-Linked Immunosorbent Assay ,Lung injury ,Granulocyte ,Toxicology ,Nitric Oxide ,Nitric oxide ,Transforming Growth Factor beta1 ,chemistry.chemical_compound ,Interferon-gamma ,Fibrosis ,Internal medicine ,medicine ,Animals ,Rats, Wistar ,Receptor ,biology ,business.industry ,Public Health, Environmental and Occupational Health ,NF-kappa B ,Granulocyte-Macrophage Colony-Stimulating Factor ,Transforming growth factor beta ,medicine.disease ,Silicon Dioxide ,Interleukin-10 ,Rats ,Disease Models, Animal ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Receptors, Tumor Necrosis Factor, Type I ,biology.protein ,Tumor necrosis factor alpha ,Collagen ,business ,Signal Transduction - Abstract
This study investigates cross-talk of the related bioactivity mediators in silica-induced pulmonary inflammatory and fibrosis on rats, which contributes to the preventive and therapeutic effect of soluble TNF-α receptor. Wistar rats received saline or 50 mg of quartz by intratracheal instillation. Rats in drug-treated groups were given soluble tumor necrosis factor-α (TNF-α) receptor (500 μg) by hypodermic injection on days 1, 5 and 8 after operation. At 7 days or 14 days after instillation, rats were killed to observe the degree of injury and expression of the related bioactivity mediators including nuclear factor KB (NF-KB), nitric oxide, interleukin-1β, interleukin-10, transforming growth factor beta 1 (TGF-β1), TNF-α, interferon-Y (IFN-Y) and granulocyte macrophage colony-stimulating factor (GM-CSF). The area percentages of type I and III collagens in intervention group were lower than those in silica group. The expression of NF-κB, TGF-β1, and COL I were lower in intervention group than in silica group(p < 0.05) and GM-CSF was significantly higher (p < 0.05) at 7 days after instillation, however, NF-κB, TGF-β1, and COL I were identically lower in intervention group than in silica group, and TNF-α, IFN-γ, and GM-CSF were higher at 14 days after instillation. It may be concluded that soluble TNF-α receptor upregulating or downregulating the expression of the related bioactivity mediators results in decreasing lung injury induced by silica.
- Published
- 2011
41. Spectroscopic investigation of the multiphoton photolysis reactions of bromomethanes (CHBr3, CHBr2Cl, CHBrCl2, and CH2Br2) at near-ultraviolet wavelengths
- Author
-
Guang-Yi Hou, Jian-Hang Dai, Chih-Hsuan Chang, Bor-Chen Chang, and Shi-Xing Yang
- Subjects
Wavelength ,Chemistry ,Excited state ,Radical ,Reactive intermediate ,Photodissociation ,Analytical chemistry ,Emission spectrum ,Physical and Theoretical Chemistry ,Near ultraviolet ,Fluorescence spectroscopy - Abstract
Nascent emission and laser-induced dispersed fluorescence spectra of products or intermediates from the multiphoton photolysis reaction of bromomethanes (CHBr(3), CHBr(2)Cl, CHBrCl(2), and CH(2)Br(2)) at 266 nm were recorded in a slow flow cell. Electronically excited species including CH (A(2)Delta, B(2)Sigma(-), and C(2)Sigma(+)), C(2) (d(3)Pi(g)), and atomic Br ((4)D(J) and (4)P(J)) were observed in the nascent emission spectra. Free radicals such CHBr or CHCl were also successfully found using laser-induced dispersed fluorescence spectroscopy. The reactive intermediate, CHBr, was seen only in the photolysis of CHBr(3), whereas CHCl was only discovered when the precursor was CHBr(2)Cl or CHBrCl(2). More experiments including the power dependence and temporal waveform measurements were conducted. The present study reports the first direct measurements of the intermediate products in the multiphoton photodissociation reaction of these bromomethanes at 266 nm. Nascent emission spectra following the photolysis at longer near-ultraviolet wavelengths (280 and 355 nm) were also acquired. On the bassis of these results, the multiphoton photodissociation mechanism of these bromomethanes at 266 nm can be confirmed.
- Published
- 2010
42. [Untitled]
- Author
-
Hai-Feng Li, Ming-Li Sun, shi-xing zhao, and Yan-Ping Wu
- Subjects
endocrine system ,business.industry ,Endoplasmic reticulum ,ATF4 ,Lung injury ,Pharmacology ,Critical Care and Intensive Care Medicine ,Salubrinal ,chemistry.chemical_compound ,Paraquat ,chemistry ,Medicine ,Signal transduction ,business - Abstract
Introduction: In this study, we aim to investigate the changes of PERK-eIF2a-ATF4 signaling pathway in endoplasmic reticulum stress after acute paraquat (PQ) poisoning; and to clear Salubrinal (Sal) effects on PERK-eIF2a-ATF4 signaling pathway and lung injury caused by paraquat. Methods: 200 Wistar
- Published
- 2013
43. New Low-Frequency Relaxation Process in La 2 CuO 4+δ by Internal Friction Experiments
- Author
-
Liu Wei, Wang Shi-Xing, Zhang Li-De, and Liu Yun-Long
- Subjects
Materials science ,Oxygen atom ,chemistry ,Relaxation process ,General Physics and Astronomy ,Torsion (mechanics) ,chemistry.chemical_element ,Thermodynamics ,Low frequency ,Maxima ,Oxygen ,Internal friction - Abstract
The low-frequency relaxation internal friction spectrum of La2CuO4+δ has been measured from -170 to 200°C in an automatic torsion apparatus at frequencies between 0.1 and 5.0 Hz. Three new relaxation processes are found with maxima, which are attributed to thermally activated diffusive jumps of oxygen atoms or vacancies in the oxygen sublattice, according to various activation enthalpies of three experimental runs. It is shown that the content of oxygen defect have important influences on the physical properties of La2CuO4+δ.
- Published
- 2000
44. [Untitled]
- Author
-
shi-xing zhao, Ming-Li Sun, and Yan-Ping Wu
- Subjects
chemistry.chemical_compound ,Paraquat ,chemistry ,business.industry ,ATF4 ,Medicine ,Lung injury ,Pharmacology ,Critical Care and Intensive Care Medicine ,business - Published
- 2013
45. Inhibition of Glycogen Synthase Kinase-3β Attenuates Glucocorticoid-Induced Suppression of Myogenic Differentiation In Vitro.
- Author
-
Ma, Zhenyu, Zhong, Zhigang, Zheng, Zhenyang, Shi, Xing-Ming, and Zhang, Weixi
- Subjects
GLYCOGEN synthase kinase-3 ,MYOBLASTS ,CELL differentiation ,MUSCULAR dystrophy in children ,GLUCOCORTICOIDS ,MYOGENESIS - Abstract
Glucocorticoids are the only therapy that has been demonstrated to alter the progress of Duchenne muscular dystrophy (DMD), the most common muscular dystrophy in children. However, glucocorticoids disturb skeletal muscle metabolism and hamper myogenesis and muscle regeneration. The mechanisms involved in the glucocorticoid-mediated suppression of myogenic differentiation are not fully understood. Glycogen synthase kinase-3β (GSK-3β) is considered to play a central role as a negative regulator in myogenic differentiation. Here, we showed that glucocorticoid treatment during the first 48 h in differentiation medium decreased the level of phosphorylated Ser9-GSK-3β, an inactive form of GSK-3β, suggesting that glucocorticoids affect GSK-3β activity. We then investigated whether GSK-3β inhibition could regulate glucocorticoid-mediated suppression of myogenic differentiation in vitro. Two methods were employed to inhibit GSK-3β: pharmacological inhibition with LiCl and GSK-3β gene knockdown. We found that both methods resulted in enhanced myotube formation and increased levels of muscle regulatory factors and muscle-specific protein expression. Importantly, GSK-3β inhibition attenuated glucocorticoid-induced suppression of myogenic differentiation. Collectively, these data suggest the involvement of GSK-3β in the glucocorticoid-mediated impairment of myogenic differentiation. Therefore, the inhibition of GSK-3β may be a strategy for preventing glucocorticoid-induced muscle degeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
46. PRODUCTION OF VACUUM POSITRONIUM ATOMS
- Author
-
Shi Xing-Jun, Guo Xue-Zhe, Weng Hui-Min, Xie Li, and Han Rong-Dian
- Subjects
Materials science ,Astrophysics::High Energy Astrophysical Phenomena ,General Physics and Astronomy ,chemistry.chemical_element ,Fraction (chemistry) ,Germanium ,Radiation ,Spectral line ,Positronium ,Positron energy ,Positron ,chemistry ,Physics::Accelerator Physics ,High Energy Physics::Experiment ,Atomic physics ,Positron annihilation - Abstract
Positronium atoms are formed efficiently by slow positron beam hitting a solid target surface in vacuum. The fraction of positrons which formed positroniums is determined by applying the "peak method" to the energy spectra of the positron annihilation radiation measured at different target temperatures and incident positron energies. The fraction is dependent on the target material, temperature and incident positron energy. For germanium, the fraction is as high as 80%.
- Published
- 1991
47. Inhibition of Glycogen Synthase Kinase-3β Attenuates Glucocorticoid-Induced Suppression of Myogenic Differentiation In Vitro.
- Author
-
Ma, Zhenyu, Zhong, Zhigang, Zheng, Zhenyang, Shi, Xing-Ming, and Zhang, Weixi
- Subjects
- *
GLYCOGEN synthase kinase-3 , *MYOBLASTS , *CELL differentiation , *MUSCULAR dystrophy in children , *GLUCOCORTICOIDS , *MYOGENESIS - Abstract
Glucocorticoids are the only therapy that has been demonstrated to alter the progress of Duchenne muscular dystrophy (DMD), the most common muscular dystrophy in children. However, glucocorticoids disturb skeletal muscle metabolism and hamper myogenesis and muscle regeneration. The mechanisms involved in the glucocorticoid-mediated suppression of myogenic differentiation are not fully understood. Glycogen synthase kinase-3β (GSK-3β) is considered to play a central role as a negative regulator in myogenic differentiation. Here, we showed that glucocorticoid treatment during the first 48 h in differentiation medium decreased the level of phosphorylated Ser9-GSK-3β, an inactive form of GSK-3β, suggesting that glucocorticoids affect GSK-3β activity. We then investigated whether GSK-3β inhibition could regulate glucocorticoid-mediated suppression of myogenic differentiation in vitro. Two methods were employed to inhibit GSK-3β: pharmacological inhibition with LiCl and GSK-3β gene knockdown. We found that both methods resulted in enhanced myotube formation and increased levels of muscle regulatory factors and muscle-specific protein expression. Importantly, GSK-3β inhibition attenuated glucocorticoid-induced suppression of myogenic differentiation. Collectively, these data suggest the involvement of GSK-3β in the glucocorticoid-mediated impairment of myogenic differentiation. Therefore, the inhibition of GSK-3β may be a strategy for preventing glucocorticoid-induced muscle degeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.