46 results on '"Xu KZ"'
Search Results
2. Repurposing promethazine hydrochloride to inhibit biofilm formation against Burkholderia thailandensis.
- Author
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Xu KZ, You C, Wang YJ, Dar OI, Yin LJ, Xiang SL, and Jia AQ
- Subjects
- Molecular Docking Simulation, Anti-Bacterial Agents pharmacology, Lipase metabolism, Lipase genetics, Gene Expression Regulation, Bacterial drug effects, Bacterial Proteins genetics, Bacterial Proteins metabolism, Humans, Quorum Sensing drug effects, Biofilms drug effects, Biofilms growth & development, Burkholderia drug effects, Burkholderia physiology, Burkholderia genetics, Promethazine pharmacology, Drug Repositioning
- Abstract
Melioidosis is a severe infectious disease caused by Burkholderia pseudomallei, an intracellular pathogen with a high mortality rate and significant antibiotic resistance. The high mortality rate and resistance to antibiotics have drawn considerable attention from researchers studying melioidosis. This study evaluated the effects of various concentrations (75, 50, and 25 µg/mL) of promethazine hydrochloride (PTZ), a potent antihistamine, on biofilm formation and lipase activity after 24 h of exposure to B. thailandensis E264. A concentration-dependent decrease in both biofilm biomass and lipase activity was observed. RT-PCR analysis revealed that PTZ treatment not only made the biofilm structure loose but also reduced the expression of btaR1, btaR2, btaR3, and scmR. Single gene knockouts of quorum sensing (QS) receptor proteins (∆btaR1, ∆btaR2, and ∆btaR3) were successfully constructed. Deletion of btaR1 affected biofilm formation in B. thailandensis, while deletion of btaR2 and btaR3 led to reduced lipase activity. Molecular docking and biological performance results demonstrated that PTZ inhibits biofilm formation and lipase activity by suppressing the expression of QS-regulated genes. This study found that repositioning PTZ reduced biofilm formation in B. thailandensis E264, suggesting a potential new approach for combating melioidosis., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2024
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3. Dopamine, an exogenous quorum sensing signaling molecule or a modulating factor in Pseudomonas aeruginosa ?
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Xiang SL, Xu KZ, Yin LJ, Rao Y, Wang B, and Jia AQ
- Abstract
Pseudomonas aeruginosa is recognized globally as an opportunistic pathogen of considerable concern due to its high virulence and pathogenicity, especially in immunocompromised individuals. While research has identified several endogenous quorum sensing (QS) signaling molecules that enhance the virulence and pathogenicity of P. aeruginosa , investigations on exogenous QS signaling molecules or modulating factors remain limited. This study found that dopamine serves as an exogenous QS signaling molecule or modulating factor of P. aeruginosa PAO1, enhancing the production of virulence factors and biofilms. Compared to the control group, treatment with 40 μM dopamine resulted in a 33.1 % increase in biofilm formation, 68.1 % increase in swimming mobility, 63.1 % increase in swarming mobility, 147.2 % increase in the signaling molecule 3-oxo-C12-HSL, and 50.5 %, 28.5 %, 27.0 %, and 33.2 % increases in the virulence factors alginate, rhamnolipids, protease, and pyocyanin, respectively. This study further explored the mechanism of dopamine regulating the biofilm formation and virulence of P. aeruginosa PAO1 through transcriptome and metabolome. Transcriptomic analysis showed that dopamine promoted the expression of virulence genes psl, alg, lasA, rhlABC , rml , and phz in P. aeruginosa PAO1. Metabolomic analysis revealed changes in the concentrations of tryptophan, pyruvate, ethanolamine, glycine, 3-hydroxybutyric acid, and alizarin. Furthermore, KEGG enrichment analysis of altered genes and metabolites indicated that dopamine enhanced phenylalanine, tyrosine, and tryptophan in P. aeruginosa PAO1. The results of this study will contribute to the development of novel exogenous QS signaling molecules or modulating factors and advance our understanding of the interactions between P. aeruginosa and the host environment., Competing Interests: The authors declare have no competing financial interests., (© 2024 The Authors.)
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- 2024
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4. An Investigation of Quorum Sensing Inhibitors against Bacillus cereus in The Endophytic Fungus Pithomyces sacchari of the Laurencia sp.
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Xiang SL, Xu KZ, Yin LJ, and Jia AQ
- Subjects
- Laurencia microbiology, Virulence Factors, China, Endophytes, Quorum Sensing drug effects, Bacillus cereus drug effects, Biofilms drug effects, Anti-Bacterial Agents pharmacology, Microbial Sensitivity Tests
- Abstract
Bacillus cereus , a common food-borne pathogen, forms biofilms and generates virulence factors through a quorum sensing (QS) mechanism. In this study, six compounds (dankasterone A, demethylincisterol A
3 , zinnimidine, cyclo-(L-Val-L-Pro), cyclo-(L-Ile-L-Pro), and cyclo-(L-Leu-L-Pro)) were isolated from the endophytic fungus Pithomyces sacchari of the Laurencia sp. in the South China Sea. Among them, demethylincisterol A3 , a sterol derivative, exhibited strong QS inhibitory activity against B. cereus . The QS inhibitory activity of demethylincisterol A3 was evaluated through experiments. The minimum inhibitory concentration (MIC) of demethylincisterol A3 against B. cereus was 6.25 μg/mL. At sub-MIC concentrations, it significantly decreased biofilm formation, hindered mobility, and diminished the production of protease and hemolysin activity. Moreover, RT-qPCR results demonstrated that demethylincisterol A3 markedly inhibited the expression of QS-related genes ( plcR and papR ) in B. cereus . The exposure to demethylincisterol A3 resulted in the downregulation of genes ( comER , tasA , rpoN , sinR , codY , nheA , hblD , and cytK ) associated with biofilm formation, mobility, and virulence factors. Hence, demethylincisterol A3 is a potentially effective compound in the pipeline of innovative antimicrobial therapies.- Published
- 2024
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5. Methyl gallate isolated from partridge tea (Mallotus oblongifolius (Miq.) Müll.Arg.) inhibits the biofilms and virulence factors of Burkholderia thailandensis.
- Author
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Xu KZ, Xiang SL, Wang YJ, Wang B, and Jia AQ
- Subjects
- Virulence Factors, Molecular Docking Simulation, Biofilms, Quorum Sensing, Anti-Bacterial Agents pharmacology, Tea, Pseudomonas aeruginosa, Mallotus Plant, Burkholderia genetics
- Abstract
Ethnopharmcological Relevance: The formation of biofilms is a factor leading to chronic infection and drug resistance in melioidosis. The production of biofilm formation and many virulence factors are regulated by quorum sensing (QS). Therefore, the discovery of QS inhibitors to reduce antibiotic abuse has attracted a lot of attention. In this case, the methanol extract of a unique ethnic medicinal plant partridge tea (Mallotus oblongifolius (Miq.) Müll.Arg.) and its isolated active compound were used as biofilms and QS inhibitors against Burkholderia thailandensis., Aim of the Study: The purpose of this study is to investigate the anti-biofilm and anti-QS effect of the ethnic medicinal plant partridge tea and its active compounds against B. thailandensis., Methods: Active compound was isolated using classical phytochemical separation techniques under activity tracking. The biofilm and virulence factors (Proteases, lipases, rhamnolipids, and motility) of B. thailandensis were used to evaluate the activity of crude extracts and isolated compounds., Results: In this study, the extract of partridge tea and MG had good QS inhibitors activity against B. thailandensis E264. MG was investigated to inhibit QS-related virulence factors and the biofilm formation against B. thailandensis E264. The lipase activity of B. thailandensis E264 decreased by 49.41% at 150 μg/mL. At 75 μg/mL and 150 μg/mL, the erasion of mature biofilms reached 28.18% and 70.87%, respectively. Correspondingly, 150 μg/mL MG could significantly decrease btaR1 and btaR3 by 55.78% and 56.24%, respectively. Contradictorily, the rhamnolipid production of B. thailandensis E264 was 1.67 folds that of the control group at 150 μg/mL MG., Conclusion: Through molecular docking analysis and biological phenotype data, we speculate that MG may inhibit the biofilms and virulence factors of B. thailandensis E264 by interfering two QS systems, BtaI1/R1 and BtaI3/R3. Therefore, MG should be one potential QSI for the treatment of Burkholderia pathogens., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2024
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6. Predictors and nomogram of in-hospital mortality in sepsis-induced myocardial injury: a retrospective cohort study.
- Author
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Xu KZ, Xu P, Li JJ, Zuo AF, Wang SB, and Han F
- Subjects
- Humans, Hospital Mortality, Retrospective Studies, Nomograms, Troponin T, Sepsis complications, Heart Injuries
- Abstract
Background: Sepsis-induced myocardial injury (SIMI) is a common organ dysfunction and is associated with higher mortality in patients with sepsis. We aim to construct a nomogram prediction model to assess the 28-day mortality in patients with SIMI. ., Method: We retrospectively extracted data from Medical Information Mart for Intensive Care (MIMIC-IV) open-source clinical database. SIMI was defined by Troponin T (higher than the 99th percentile of upper reference limit value) and patients with cardiovascular disease were excluded. A prediction model was constructed in the training cohort by backward stepwise Cox proportional hazards regression model. The concordance index (C-index), area under the receiver operating characteristics curve (AUC), net reclassification improvement (NRI), integrated discrimination improvement (IDI), calibration plotting and decision-curve analysis (DCA) were used to evaluate the nomogram., Results: 1312 patients with sepsis were included in this study and 1037 (79%) of them presented with SIMI. The multivariate Cox regression analysis in all septic patients revealed that SIMI was independently associated with 28-day mortality of septic patients. The risk factors of diabetes, Apache II score, mechanical ventilation, vasoactive support, Troponin T and creatinine were included in the model and a nomogram was constructed based on the model. The C-index, AUC, NRI, IDI, calibration plotting and DCA showed that the performance of the nomogram was better than the single SOFA score and Troponin T., Conclusion: SIMI is related to the 28-day mortality of septic patients. The nomogram is a well-performed tool to predict accurately the 28-day mortality in patients with SIMI., (© 2023. The Author(s).)
- Published
- 2023
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7. Interleukin-1β Protection Against Experimental Sepsis in Mice.
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Guo HL, Shi FD, Zhou Q, Liu QY, Wang YX, Song Y, Wu ZS, Shi YH, Zhang L, Xu KZ, and Song GD
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- Animals, Bone Marrow Cells drug effects, Bone Marrow Cells metabolism, Cell Movement drug effects, Cell Movement physiology, Dose-Response Relationship, Drug, Interleukin-1beta pharmacology, Male, Mice, Mice, Inbred C57BL, Sepsis chemically induced, Sepsis metabolism, Disease Models, Animal, Interleukin-1beta therapeutic use, Sepsis prevention & control
- Abstract
The inflammatory response involving interleukin-1β (IL-1β) has been thought to play an important role in the development of late-phase sepsis. However, in this study, we wanted to explore the possibility of using IL-1β to improve the prognosis of sepsis by triggering local differentiation of bone marrow cells (BMCs) into regulatory dendritic cells (DCs) in vivo, thereby reversing the immune paralysis in late-phase sepsis. Sepsis mouse models were induced by cecal ligation and puncture (CLP) and lethal Escherichia coli O18 infection. Mice were injected intraperitoneally with IL-1β after CLP and after the lethal infection. Septic BMCs and liver immune cells were isolated at 0, 3, 6, 9, and 14 days post-CLP. BMCs and liver cells isolated from septic mice treated with IL-1β were adoptively transferred into CLP mice. GFP
+ -C57BL/6 parabiosis models were established. Serum IL-1β levels were determined by enzyme-linked immunosorbent assay (ELISA) kit, and the number, ratio, and phenotype of immune cells were observed by flow cytometry. IL-1β treatment improved the survival of sepsis and increased the numbers of BMCs and liver immune cells in septic mice. Moreover, IL-1β stimulation increased the number and the percentage of CD11c- CD45RBhigh DCs in septic BM and liver. Adoptive transfer of septic BMCs, liver immune cells, and CD11c- CD45RBhigh DCs treated with IL-1β into CLP mice attenuated sepsis. IL-1β triggered the redistribution of CD11c- CD45RBhigh DCs as well as BMCs in parabiosis models. IL-1β protects against sepsis by stimulating local proliferation and differentiation of BMCs into CD11c- CD45RBhigh DCs at immune organs and non-immune organs.- Published
- 2021
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8. Enhancing the decolorization activity of Bacillus pumilus W3 CotA-laccase to Reactive Black 5 by site-saturation mutagenesis.
- Author
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Ma H, Xu KZ, Wang YJ, Yan N, Liao XR, and Guan ZB
- Subjects
- Bacterial Proteins genetics, Coloring Agents, Molecular Docking Simulation, Mutagenesis, Naphthalenesulfonates, Bacillus pumilus genetics, Laccase genetics
- Abstract
Reactive Black 5 (RB5) is a typical refractory azo dye. Widespread utilization of RB5 has caused a variety of environmental and health problems. The enzymatic degradation of RB5 can be a promising solution due to its superiority as an eco-friendly and cost-competitive process. Bacterial CotA-laccase shows great application prospect to eliminate hazardous dyes from wastewater. However, efficient decolorization of RB5 CotA-laccase generally requires the participation of costly, toxic mediators. In the present study, we modified the amino acids Thr415 and Thr418 near the type 1 copper site and the amino acid Gln442 at the entrance of the substrate-binding pocket of Bacillus pumilus W3 CotA-laccase to boost its RB5 decolorization activity based on molecular docking analysis and site-saturation mutagenesis. Through the strategies, two double site mutants T415D/Q442A and T418K/Q442A obtained demonstrated 43.94 and 52.64% RB5 decolorization rates in the absence of a mediator at pH 10.0, respectively, which were about 3.70- and 4.43-fold higher compared with the wild-type CotA-laccase. Unexpectedly, the catalytic efficiency of the T418K/Q442A to ABTS was enhanced by 5.33-fold compared with the wild-type CotA-laccase. The mechanisms of conferring enhanced activity to the mutants were proposed by structural analysis. In summary, the mutants T415D/Q442A and T418K/Q442A have good application potentials for the biodegradation of RB5. KEY POINTS: • Three amino acids of CotA-laccase were manipulated by site-saturation mutagenesis. • Decolorization rate of two mutants to RB5 was enhanced 3.70- and 4.43-fold, respectively. • The mechanisms of awarding enhanced activity to the mutants were supposed.
- Published
- 2020
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9. Recombinant Horseradish Peroxidase C1A Immobilized on Hydrogel Matrix for Dye Decolorization and Its Mechanism on Acid Blue 129 Decolorization.
- Author
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Wang YJ, Xu KZ, Ma H, Liao XR, Guo G, Tian F, and Guan ZB
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- Biotransformation, Color, Enzymes, Immobilized chemistry, Horseradish Peroxidase chemistry, Hydrogen-Ion Concentration, Recombinant Proteins chemistry, Temperature, Anthraquinones metabolism, Coloring Agents metabolism, Enzymes, Immobilized metabolism, Horseradish Peroxidase metabolism, Hydrogels chemistry, Recombinant Proteins metabolism, Sulfonic Acids metabolism
- Abstract
In this study, horseradish peroxidase C1A (HRP C1A) from Armoracia rusticana was expressed in Escherichia coli as an inclusion body. Subsequently, an active recombinant HRP C1A was obtained by refolding gradually using dilution-ultrafiltration. The recombinant HRP C1A was immobilized on agarose-chitosan hydrogel at 86.9 ± 2.5% of immobilization efficiency. After immobilization of the recombinant HRP C1A, the pH and temperature stability were improved and the reusability of the recombinant HPR C1A was achieved. The immobilized HRP C1A activity was retained above 80% after 6 cycles. The immobilized recombinant HRP C1A was used for the decolorization of four various dyes, including acid blue 129 (AB129), methyl blue (MB), methyl red (MR), and trypan blue (TB). The decolorization rates are all more than 70%, among which the decolorization effect of AB129 was the most significant (the decolorization rate was 76.3 ± 1.6%). Furthermore, a plausible decolorization pathway for AB129 was proposed based on the identified intermediates by ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS). This is the first report of the putative mechanism on the decolorization of AB129 by HRP.
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- 2020
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10. Extracellular expression of mutant CotA-laccase SF in Escherichia coli and its degradation of malachite green.
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Xu KZ, Ma H, Wang YJ, Cai YJ, Liao XR, and Guan ZB
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- Coloring Agents toxicity, Escherichia coli genetics, Escherichia coli metabolism, Laccase genetics, Mutation, Rosaniline Dyes toxicity, Coloring Agents metabolism, Laccase metabolism, Rosaniline Dyes metabolism
- Abstract
In this study, mutant CotA-laccase SF was successfully expressed in Escherichia coli by co-expression with phospholipase C. The optimized extracellular expression of CotA-laccase SF was 1257.22 U/L. Extracellularly expressed CotA-laccase SF exhibits enzymatic properties similar to intracellular CotA-laccase SF. CotA-laccase SF could decolorize malachite green (MG) under neutral and alkaline conditions. The K
m and kcat values of CotA-laccase SF to MG were 39.6 mM and 18.36 s-1 . LC-MS analysis of degradation products showed that MG was finally transformed into 4-aminobenzophenone and 4-aminophenol by CotA-laccase. The toxicity experiment of garlic root tip cell showed that the toxicity of MG metabolites decreased. In summary, CotA-laccase SF had a good application prospect for degrading malachite green., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2020
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11. Enhancement in catalytic activity of CotA-laccase from Bacillus pumilus W3 via site-directed mutagenesis.
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Xu KZ, Wang HR, Wang YJ, Xia J, Ma H, Cai YJ, Liao XR, and Guan ZB
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- Bacillus pumilus enzymology, Bacterial Proteins genetics, Bacterial Proteins metabolism, Biotransformation genetics, Catalysis, Coloring Agents chemistry, Coloring Agents metabolism, Genetic Enhancement methods, Laccase chemistry, Mutation, Organisms, Genetically Modified, Temperature, Bacillus pumilus genetics, Laccase genetics, Laccase metabolism, Mutagenesis, Site-Directed, Protein Engineering methods
- Abstract
CotA-laccases are potential enzymes that are widely used in decolorization of dyes and degradation of toxic substances. In this study, a novel CotA-laccase gene from Bacillus pumilus W3 was applied for rational design. After a series of site-directed genetic mutations, the mutant S208G/F227A showed a 5.1-fold higher catalytic efficiency (k
cat /Km ) than the wild-type CotA-laccase did. The optimal pH of S208G/F227A was 3.5 with ABTS as substrate. The residual activity of mutant S208G/F227A was more than 80% after incubated for 10 h at pH 7-11. Mutant S208G/F227A showed optimal temperature at 80°C with ABTS as substrate. The thermal stability of mutant laccase S208G/F227A was lower than that of wild-type CotA-laccase. This study showed that Gly208 and Ala227 play key roles in catalytic efficiency and it is possible to improve catalytic efficiency of CotA-laccase through site-directed mutagenesis., (Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)- Published
- 2020
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12. Lipoprotein(a) and Atherosclerotic Cardiovascular Disease: Current Understanding and Future Perspectives.
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Wu MF, Xu KZ, Guo YG, Yu J, Wu Y, and Lin LM
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- Animals, Anticholesteremic Agents therapeutic use, Atherosclerosis etiology, Atherosclerosis genetics, Atherosclerosis prevention & control, Biomarkers blood, Blood Component Removal, Humans, Hyperlipoproteinemia Type II complications, Hyperlipoproteinemia Type II genetics, Hyperlipoproteinemia Type II therapy, Lipoprotein(a) genetics, Oligonucleotides, Antisense therapeutic use, Risk Assessment, Risk Factors, Treatment Outcome, Up-Regulation, Atherosclerosis blood, Hyperlipoproteinemia Type II blood, Lipoprotein(a) blood
- Abstract
Purpose: To review current knowledge of elevated lipoprotein(a) [Lp(a)] levels in relation to atherosclerotic cardiovascular disease (ASCVD) and discuss their potential use as biomarkers and therapeutic approaches in clinical practice., Methods: We summarized the current understanding and recent advances in the structure, metabolism, atherogenic mechanisms, standardized laboratory measurement, recommended screening populations, and prognostic value of Lp(a), with a special focus on the current potential treatment approaches for hyperlipoprotein(a)emia in patients with ASCVD., Results: Lp(a) is composed of LDL-like particle and characteristic apolipoprotein(a) [apo(a)] connected by a disulfide bond. Substantial evidence shows that elevated plasma Lp(a) level is a heritable, independent, and possibly causal risk factor for ASCVD through its proatherogenic, proinflammatory, and potentially prothrombotic properties. Current guidelines recommend Lp(a) measurement for patients with an intermediate-high risk of ASCVD, familial hypercholesterolemia, a family history of early ASCVD or elevated Lp(a), and progressive ASCVD despite receiving optimal therapy. Traditional Lp(a)-lowering approaches such as niacin, PCSK9 inhibitors, mipomersen, lomitapide, and lipoprotein apheresis were associated with a non-specific and limited reduction of Lp(a), intolerable side effects, invasive procedure, and high expense. The phase 2 randomized controlled trial of antisense oligonucleotide against the apo(a) encoding gene LPA mRNA showed that IONIS-APO(a)-L
RX could specifically reduce the level of Lp(a) by 90% with good tolerance, which may become a promising candidate for the prevention and treatment of ASCVD in the future., Conclusions: It is reasonable to measure Lp(a) levels to reclassify ASCVD risk and manage individuals with elevated Lp(a) to further reduce the residual risk of ASCVD, especially with IONIS-APO(a)-LRX .- Published
- 2019
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13. Evidence for selective adjustments of inhibitory control in a variant of the stop signal task.
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Xu KZ, Mayse JD, and Courtney S
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- Adolescent, Adult, Eye Movements physiology, Female, Humans, Male, Photic Stimulation, Psychomotor Performance, Reaction Time physiology, Young Adult, Attention, Executive Function physiology, Inhibition, Psychological, Signal Detection, Psychological physiology, Social Adjustment
- Abstract
The ability to inhibit actions inappropriate for the context is essential for meeting the shifting demands of complex environments. The stop signal task (SST) has been used in many previous studies to examine the interactions between go and stop responses in a cognitively demanding task involving attention, conflict resolution, and motor plan selection. The current study uses a variant of the SST, in which the continue signal instructs participants to proceed with the go response they were preparing. Reaction times (RTs) on continue trials were bimodally distributed, suggesting that an aspect of inhibition was involved in at least some of the trials. We investigated whether the cognitive processes delaying the generation of a behavioural response on continue trials are the same as for stop trials. We found improvement of stop signal reaction times (SSRTs) following stop trials, but the decrease in continue signal reaction times (CSRTs) was not significant. No improvement in either SSRT or CSRT was found following continue trials, suggesting that activation of the processes delaying the response on continue trials is insufficient to drive subsequent adjustments in SSRT or CSRT. In addition, go RTs only slowed following stop trials. These effects may suggest the presence of a selective learning process, which requires that the initial inhibition captured by SSRT and CSRT be combined with recognition of the stop signal specifically to affect subsequent performance.
- Published
- 2019
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14. High Mobility Group Protein 1 Reverses Immune System Paralysis in Late-Phase Sepsis.
- Author
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Liu QY, Wang YX, Wu ZS, Shi ZW, Wu X, Chen X, Yang Z, and Xu KZ
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- Adoptive Transfer, Animals, Bone Marrow Cells immunology, Cecum, Cell Differentiation, Dendritic Cells immunology, Disease Models, Animal, Ligation, Mice, Inbred C3H, Mice, Inbred C57BL, Parabiosis, Pneumonia microbiology, Pseudomonas Infections blood, Pseudomonas Infections drug therapy, Pseudomonas aeruginosa immunology, Sepsis microbiology, Toll-Like Receptor 4 immunology, HMGB1 Protein immunology, HMGB1 Protein pharmacology, Pneumonia immunology, Sepsis drug therapy, Sepsis immunology
- Abstract
High mobility group protein 1 (HMGB1) is considered to be the primary inflammatory factor triggering immune paralysis in late-phase sepsis. In this study, however, we wanted to explore the possibility of using HMGB1 to boost local differentiation of bone marrow cells (BMCs) into regulatory dendritic cells (DCs) in vivo , thereby inducing immune reversal in late-phase sepsis and improving the prognosis. For this purpose, sepsis was induced by cecal ligation and puncture (CLP). Mice were injected intraperitoneally with HMGB1 (10, 50, or 250 μg/kg of body weight) 7 days before CLP. BMCs and liver immune cells were isolated at 0, 3, 5, and 7 days post-CLP. Mice were intranasally infected with Pseudomonas aeruginosa 3 days post-CLP as a secondary pneumonia infection model. BMCs and liver cells isolated from septic mice pretreated with HMGB1 were adoptively transferred into CLP mice. GFP
+ -C57BL/6 and C3H/HeN-C3H/HeJ parabiosis models were established. We found that HMGB1 pretreatment improved the survival of sepsis and increased the numbers of BMCs and liver immune cells in CLP mice. Furthermore, HMGB1 stimulation improved survival in the secondary pneumonia infection model. HMGB1 increased the number as well as the percentage of CD11c- CD45RBhigh DCs in septic BM and liver. Adoptive transfer of septic cells pretreated with HMGB1 into CLP mice attenuated sepsis. HMGB1 enhanced the redistribution of CD11c- CD45RBhigh DCs through TLR4 signaling in parabiosis models. We conclude that HMGB1 triggers immune reversal through the mobilization, redistribution, and local immune differentiation of BMCs, thereby compensating for impaired immunity and leading to sufficient bacterial eradication., (Copyright © 2018 American Society for Microbiology.)- Published
- 2018
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15. Polysaccharides from Bupleurum Induce Immune Reversal in Late Sepsis.
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Wang YX, Liu QY, Zhang M, Yang Z, Pei X, Wu X, Chen X, Hong J, and Xu KZ
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- Animals, Burns microbiology, Flow Cytometry, Male, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Pseudomonas aeruginosa pathogenicity, Sepsis microbiology, Bupleurum chemistry, Burns drug therapy, Burns immunology, Polysaccharides therapeutic use, Sepsis drug therapy, Sepsis immunology
- Abstract
Background: Bupleurum chinense, a well-known Traditional Chinese Medicine, has been used for thousands of years in China. In this study, we would suggest that Bupleurum polysaccharides (BPS) could improve the prognosis of sepsis through its impact on redistribution of BMCs, which triggers immune reversal in late sepsis., Methods: BALB/c mice were divided into five groups: sham burn group, burn plus P aeruginosa group, burn plus P aeruginosa with BPS (40 mg/kg, 100 mg/kg, and 250 mg/kg) treatment group, and they were sacrificed at post-burn day (PBD) 0, 3, 5, and 7. BMCs, liver cells, and dendritic cells (DCs) were harvested. Flow cytometry was used to determine the change of phenotypes of DCs and isolate these cells. Cytometric beads array was utilized to analyze the level of inflammatory factors. Cell therapy of BMCs, liver cells, and DCs was administrated to explore the protective role of regional organ immunity., Results: BPS could decrease the lethality of burn sepsis in a dose-dependent fashion and increase both the percentage of CD11cCD45RB DCs in bone marrow (BM) and liver and the number of BMCs and liver cells significantly. Cell therapy of BMCs, liver cells, and CD11cCD45RB DCs at PBD7 could protect septic mice from sepsis., Conclusion: BPS has shown its potential in promoting the prognosis of post-burn sepsis through its effect on immune redistribution of BMCs, especially via differentiation of CD11cCD45RB DC cells in BM and nonimmune organs to induce immune reversal in late sepsis.
- Published
- 2018
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16. Neural Basis of Cognitive Control over Movement Inhibition: Human fMRI and Primate Electrophysiology Evidence.
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Xu KZ, Anderson BA, Emeric EE, Sali AW, Stuphorn V, Yantis S, and Courtney SM
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- Action Potentials physiology, Adolescent, Adult, Animals, Conditioning, Operant, Female, Humans, Image Processing, Computer-Assisted, Macaca mulatta, Male, Neurons physiology, Oxygen blood, Psychomotor Performance, Reaction Time physiology, Young Adult, Brain Mapping, Executive Function physiology, Inhibition, Psychological, Movement physiology, Prefrontal Cortex cytology, Prefrontal Cortex diagnostic imaging, Prefrontal Cortex physiology
- Abstract
Executive control involves the ability to flexibly inhibit or change an action when it is contextually inappropriate. Using the complimentary techniques of human fMRI and monkey electrophysiology in a context-dependent stop signal task, we found a functional double dissociation between the right ventrolateral prefrontal cortex (rVLPFC) and the bi-lateral frontal eye field (FEF). Different regions of rVLPFC were associated with context-based signal meaning versus intention to inhibit a response, while FEF activity corresponded to success or failure of the response inhibition regardless of the stimulus response mapping or the context. These results were validated by electrophysiological recordings in rVLPFC and FEF from one monkey. Inhibition of a planned behavior is therefore likely not governed by a single brain system as had been previously proposed, but instead depends on two distinct neural processes involving different sub-regions of the rVLPFC and their interactions with other motor-related brain regions., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
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17. EXPRESSION AND EFFECTS OF MUTANT Bombyx mori ACETYLCHOLINESTRASE1 IN BmN CELLS.
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Wang BB, Xie Y, Li FC, Ni M, Xu KZ, Tian JH, Hu JS, Xue B, Shen WD, and Li B
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- Animals, Bombyx drug effects, Cell Line, Cholinesterase Inhibitors pharmacology, Insecticides pharmacology, Mutation, Organothiophosphorus Compounds pharmacology, Physostigmine pharmacology, Transfection, Acetylcholinesterase genetics, Acetylcholinesterase metabolism, Bombyx enzymology, Bombyx genetics, Gene Expression Regulation drug effects, Insect Proteins genetics, Insect Proteins metabolism
- Abstract
The main mechanism of toxicity of organophosphate (OP) and carbamate (CB) insecticides is their irreversible binding and inhibition of acetylcholinestrase (AChE), encoded by ace1 (acetylcholinestrase gene 1), leading to eventual death of insects. Mutations in AChE may significantly reduce insects susceptibility to these pesticides. Bombyx mori is an important beneficial insect, and no OP- or CB-resistant strains have been generated. In this study, wild-type ace1 (wace1) and mutant ace1 (mace1) were introduced into BmN cells, confirmed by screening and identification. The expression of wace1 and mace1 in the cells was confirmed by Western blot and their expression levels were about 21-fold higher than the endogenous ace1 level. The activities of AChE in wace1 and mace1 transgenic cells were 10.6 and 20.2% higher compared to control cells, respectively. mace1 transgenic cells had higher remaining activity than wace1 transgenic cells under the treatment of physostigmine (a reversible cholinesterase inhibitor) and phoxim (an OP acaricide). The results showed that ace1 transgene can significantly improve ace1 expression, and ace1 mutation at a specific site can reduce the sensitivity to AChE inhibitors. Our study provides a new direction for the exploration of the relationship between AChE mutations and drug resistance., (© 2016 Wiley Periodicals, Inc.)
- Published
- 2016
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18. Effects of TiO2 nanoparticles on nutrition metabolism in silkworm fat body.
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Tian JH, Hu JS, Li FC, Ni M, Li YY, Wang BB, Xu KZ, Shen WD, and Li B
- Abstract
Silkworm (Bombyx mori) is an important economic insect with a fat body that plays a crucial role in the storage and transfer of nutrients. It is also known that TiO2 nanoparticles (NPs) can improve feed efficiency and promote silk protein synthesis in the silkworm. In this study, we profiled gene expression in the silkworm fat body after TiO2 NP treatment, validated the major RNA-seq findings, and determined the contents of trehalose and triglyceride, the activity of lipase, and the amount of total proteins. RNA-seq analysis revealed that TiO2 NP treatment caused significant expression changes in 341 genes (P≤0.01), 138 of which were upregulated while the other 203 were downregulated. The expression levels of two target genes in the insulin signaling pathway and two protein metabolism-related target genes, three lipid metabolism-associated target genes, two carbohydrate metabolism related target genes and expression levels of seven heat shock protein genes were increased, and that of threonine dehydratase gene and fatty acid transport protein gene were decreased. The RNA-seq results of 16 genes were validated by quantitative real-time PCR. The lipase activity, content of trehalose, and amount of total proteins were elevated by 3.86-fold, 1.34-fold, and 1.21-fold, respectively, and the content of triglyceride was decreased by 0.94-fold after TiO2 NP treatment. These results indicated that TiO2 NPs activated the insulin signaling pathway, promoted the metabolism of protein, fat, and carbohydrate, and improved nutrition metabolism. Our study provides new support for the understanding of the beneficial effect of TiO2 NPs on silkworm nutrient metabolism., (© 2016. Published by The Company of Biologists Ltd.)
- Published
- 2016
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19. Mechanisms of TiO2 NPs-induced phoxim metabolism in silkworm (Bombyx mori) fat body.
- Author
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Hu JS, Li FC, Xu KZ, Ni M, Wang BB, Tian JH, Li YY, Shen WD, and Li B
- Subjects
- Animals, Cytochrome P-450 Enzyme System genetics, Cytochrome P-450 Enzyme System metabolism, Oxidative Stress, Bombyx metabolism, Nanoparticles metabolism, Organothiophosphorus Compounds metabolism, Titanium metabolism
- Abstract
Silkworm is an important economic insect. Abuse of organophosphorus pesticides in recent years often leads to poisoning of silkworms, which significantly affects sericulture development by reducing silk production. Previous studies have shown that TiO2 NPs can effectively mitigate the damages caused by organophosphorus pesticides in silk glands and nerve tissues. The fat body is an important metabolic detoxification organ of silkworms, but it is unknown whether TiO2 NPs affect pesticide metabolism in fat body. In this study, we characterized the transcription of antioxidant genes and enzyme activity in fat body after TiO2 NPs and phoxim treatments using transcriptome sequencing, real-time PCR, and enzyme activity assay. Transcriptome sequencing detected 10 720, 10 641, 10 403, and 10 489 genes for control group, TiO2 NPs group, phoxim group, and TiO2 NPs+phoxim group, respectively. The TiO2 NPs+phoxim group had 705 genes with significantly differential expression (FDR<0.001), among which the antioxidant genes thioredoxin reductase 1 and glutathione S-transferase omega 3 were significantly upregulated. In phoxim group, the expression levels of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase delta (GSTd), and thioredoxin peroxidase (TPx) were increased by 1.365 -fold, 1.335 -fold, 1.642 -fold, and 1.765 -fold, respectively. The level changes of SOD, CAT, GSTd, and TPx were validated by real time PCR. The contents of reactive oxygen species (ROS), malondialdehyde (MDA), and hydrogen peroxide (H2O2) were increased by 1.598 -fold, 1.946 -fold, and 1.506 -fold, respectively, indicating that TiO2 NPs treatment can relieve phoxim-induced oxidative stress. To clarify the mechanism of TiO2 NPs's effect, the transcription levels of P450 gene family were measured for the TiO2 NPs+phoxim group; the expression levels of CYP4M5, CYP6AB4, CYP6A8, and CYP9G3 were elevated by 2.784 -fold, 3.047 -fold, 2.254 -fold, and 4.253 -fold, respectively, suggesting that high expression of P450 family genes can enhance the metabolism of phoxim in the fat body. The results of this study indicated that TiO2 NPs treatment promoted the transcriptional expression of the P450 family genes to improve the fat body's ability to metabolize phoxim and reduce phoxim-induced oxidative stress. This may be the main mechanism of TiO2 NPs' mitigation of phoxim-induced damages in the fat body., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2016
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20. Effects of mutations on the structure and function of silkworm type 1 acetylcholinesterase.
- Author
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Wang BB, Li FC, Xu KZ, Ni M, Hu JS, Tian JH, Li YY, Shen WD, and Li B
- Subjects
- Acetylcholinesterase chemistry, Acetylcholinesterase physiology, Animals, Models, Molecular, Plasmids, Acetylcholinesterase genetics, Bombyx enzymology, Mutation
- Abstract
AChE is the target of organophosphate (OP) and carbamate (CB) pesticides, and mutations in the gene can significantly reduce insects' sensitivity to these pesticides. Bombyx mori is highly sensitive to pesticides. To investigate the effects of mutations on AChE1 structure and function, we used a prokaryotic system to express B.mori wild type AChE1 (wAChE1) and mutant AChE1 (mAChE1) in this study. Active AChE1 proteins were obtained after refolding and purification, and wAChE1 and mAChE1 had similar activities. After incubation with 10(-6)M physostigmine and 10(-3)mg/mL phoxim, the remaining enzyme activity of mAChE1 was 4.42% and 8.86% higher than that of wAChE1's, respectively. Three-dimensional analysis of mutation AChE1 (mAChE1) revealed that the Ser and Ala side chains extended toward the central part of S285 with distances of just 2.80Å and 3.68Å, respectively, which changed the spatial structure of the active center and reduced its sensitivity to pesticides. These results indicated that the mutations altered the 3D structure of AChE1, which may affect the binding of physostigmine and phoxim to the serine residue at the active center, leading to reduced sensitivity. Our study helps understand the relationship between AChE1 mutations and pesticide resistance and provides a new direction for the cultivation of new pesticide-resistant varieties of B.mori., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2016
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21. Nanoparticulate anatase TiO2 (TiO2 NPs) upregulates the expression of silkworm (Bombyx mori) neuropeptide receptor and promotes silkworm feeding, growth, and silking.
- Author
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Ni M, Zhang H, Li FC, Wang BB, Xu KZ, Shen WD, and Li B
- Subjects
- Animals, Bombyx drug effects, Feeding Behavior, Gene Expression, Insect Proteins genetics, Larva drug effects, Larva physiology, MAP Kinase Signaling System, Nanoparticles chemistry, Particle Size, Receptors, G-Protein-Coupled genetics, Receptors, Neuropeptide genetics, Titanium chemistry, Up-Regulation drug effects, Bombyx physiology, Insect Proteins metabolism, Receptors, G-Protein-Coupled metabolism, Receptors, Neuropeptide metabolism, Silk biosynthesis, Titanium pharmacology
- Abstract
Bombyx mori orphan G protein-coupled receptor, BNGR-A4, is the specific receptor of B. mori neuropeptide F (BmNPFR, neuropeptide F designated NPF). BmNPFR binds specifically and efficiently to B. mori neuropeptides BmNPF1a and BmNPF1b, which activates the ERK1/2 signaling pathway to regulate B. mori food intake and growth. Titanium dioxide nanoparticles (TiO2 NPs) can promote B. mori growth. However, whether the mechanisms of TiO2 NPs' effects are correlated with BmNPFR remains unknown. In this study, the effects of TiO2 NPs (5mg/L) feeding and BmNPFR-dsRNA injection on B. mori food intake and growth were investigated; after TiO2 NPs treatments, B. mori food intake, body weight, and cocoon shell weight were 5.82%, 4.64%, and 9.30% higher, respectively, than those of controls. The food intake, body weight, and cocoon shell weight of the BmNPFR-dsRNA injection group were reduced by 8.05%, 6.28%, and 6.98%, respectively, compared to the control. After TiO2 NPs treatment for 72h, the transcriptional levels of BmNPFR, BmNPF1a, and BmNPF1b in the midgut were 1.58, 1.43, and 1.34-folds, respectively, of those of the control, but 1.99, 2.26, and 2.19-folds, respectively, of the BmNPFR-dsRNA injection group; the phosphorylation level of MAPK was 24.03% higher than the control, while the phosphorylation level of BmNPFR-dsRNA injection group was 71.00% of control. The results indicated that TiO2 NPs affect B. mori feeding and growth through increasing the expression of BmNPFR. This study helps clarify the roles of BmNPF/BmNPFR system in TiO2 NPs' effects on B. mori feeding, growth, and development., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
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22. Differentially expressed genes in the fat body of Bombyx mori in response to phoxim insecticide.
- Author
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Gu ZY, Li FC, Wang BB, Xu KZ, Ni M, Zhang H, Shen WD, and Li B
- Subjects
- Animals, Fat Body metabolism, Gene Expression Profiling, Oligonucleotide Array Sequence Analysis, Bombyx genetics, Fat Body drug effects, Gene Expression Regulation drug effects, Genes, Insect drug effects, Insecticides pharmacology, Organothiophosphorus Compounds pharmacology
- Abstract
The silkworm, Bombyx mori, is an economically important insect. However, poisoning of silkworms by organophosphate pesticides causes tremendous loss to the sericulture. The fat body is the major tissue involved in detoxification and produces antimicrobial peptides and regulates hormones. In this study, a microarray system comprising 22,987 oligonucluotide 70-mer probes was employed to examine differentially expressed genes in the fat body of B. mori exposed to phoxim insecticide. The results showed that a total of 774 genes were differentially expressed upon phoxim exposure, including 500 up-regulated genes and 274 down-regulated genes. The expression levels of eight detoxification-related genes were up-regulated upon phoxim exposure, including six cytochrome P450s and two glutathione-S-transferases. It was firstly found that eight antimicrobial peptide genes were down-regulated, which might provide important references for studying the larvae of B. mori become more susceptible to microbial infections after phoxim treatment. In addition, we firstly detected the expression level of metamorphosis-related genes after phoxim exposure, which may lead to impacted reproduction. Our results may facilitate the overall understanding of the molecular mechanism of multiple pathways following exposure to phoxim insecticide in the fat body of B. mori., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2015
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23. Identification and characterization of six cytochrome P450 genes belonging to CYP4 and CYP6 gene families in the silkworm, Bombyx mori.
- Author
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Li B, Zhang H, Ni M, Wang BB, Li FC, Xu KZ, Shen WD, Xia QY, and Zhao P
- Subjects
- Amino Acid Sequence, Animals, Bombyx drug effects, Computational Biology, Conserved Sequence, Cytochrome P-450 Enzyme System metabolism, DNA, Complementary genetics, Gene Expression Regulation, Insecticides toxicity, Molecular Sequence Data, Pyrethrins toxicity, RNA genetics, Rutin toxicity, Sequence Analysis, DNA, Bombyx genetics, Cytochrome P-450 Enzyme System genetics, Insect Proteins genetics, Multigene Family
- Abstract
It was predicted that the genome of silkworm, Bombyx mori, has at least 79 P450 genes; however, P450 genes that are related to the catabolism of exogenous compounds were not reported. In this study we cloned two CYP4 (named CPY4M5 and CYP4M9) and four CYP6 (named CYP6AB5, CYP6AE9, CYP6AE22 and CYP6AU1) genes by using both bioinformatics and RT-PCR approaches. Sequence analysis showed that these genes contained conserved P450 gene sequence regions and one conserved intron. CYP4M5 and CYP4M9 genes were clustered together in a mode of "head-to-tail" possibly due to gene duplication. Blast analysis showed that these P450 genes shared significant similarity with CYP4 and CYP6 genes that are involved in the catabolism and detoxification of exogenous compounds in other insect species. RT-PCR results showed that these P450 genes were highly expressed in the midgut and fat body of B. mori. As the instar age increased, these P450 genes exhibit different expression patterns. When B. mori was exposed to 1.75 × 10(-5)% of cypermethrin, 3.5 × 10(-6)% of cypermethrin and 0.1% of rutin, expression of CYP6AB5 was increased by 2.3-fold, 2.2-fold and 1.9-fold, respectively. Exposure of B. mori to 0.1% quercetin does not change the expression of CYP6AB5. In contrast, expression of the other five P450 genes was inhibited after exposed to these compounds.
- Published
- 2014
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24. Visual space is compressed in prefrontal cortex before eye movements.
- Author
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Zirnsak M, Steinmetz NA, Noudoost B, Xu KZ, and Moore T
- Subjects
- Animals, Electrodes, Fixation, Ocular physiology, Humans, Macaca mulatta, Male, Models, Neurological, Neurons physiology, Prefrontal Cortex cytology, Retina physiology, Visual Acuity physiology, Visual Fields physiology, Prefrontal Cortex physiology, Saccades physiology, Visual Perception physiology
- Abstract
We experience the visual world through a series of saccadic eye movements, each one shifting our gaze to bring objects of interest to the fovea for further processing. Although such movements lead to frequent and substantial displacements of the retinal image, these displacements go unnoticed. It is widely assumed that a primary mechanism underlying this apparent stability is an anticipatory shifting of visual receptive fields (RFs) from their presaccadic to their postsaccadic locations before movement onset. Evidence of this predictive 'remapping' of RFs has been particularly apparent within brain structures involved in gaze control. However, critically absent among that evidence are detailed measurements of visual RFs before movement onset. Here we show that during saccade preparation, rather than remap, RFs of neurons in a prefrontal gaze control area massively converge towards the saccadic target. We mapped the visual RFs of prefrontal neurons during stable fixation and immediately before the onset of eye movements, using multi-electrode recordings in monkeys. Following movements from an initial fixation point to a target, RFs remained stationary in retinocentric space. However, in the period immediately before movement onset, RFs shifted by as much as 18 degrees of visual angle, and converged towards the target location. This convergence resulted in a threefold increase in the proportion of RFs responding to stimuli near the target region. In addition, like in human observers, the population of prefrontal neurons grossly mislocalized presaccadic stimuli as being closer to the target. Our results show that RF shifts do not predict the retinal displacements due to saccades, but instead reflect the overriding perception of target space during eye movements.
- Published
- 2014
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25. Characteristics of phoxim-exposed gene transcription in the silk gland of silkworms.
- Author
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Ma L, Xie Y, Gu ZY, Wang BB, Li FC, Xu KZ, Shen WD, and Li B
- Subjects
- Animals, Bombyx genetics, Gene Expression Profiling, Insect Proteins genetics, Bombyx drug effects, Bombyx metabolism, Insect Proteins metabolism, Organothiophosphorus Compounds pharmacology
- Abstract
Silkworm (Bombyx mori), a model Lepidoptera insect, is an important economic insect. Its silk gland is the important organ for silk protein synthesis and secretion. Phoxim exposure causes deficient cocooning of silkworm and has become one of the major negative factors for the silk industry. To study the impact of phoxim exposure on silk gland, using gene chip technology, we examined differentially expressed genes in silk gland after silkworms were exposed to phoxim (4.0μg/mL) for 24h. Functional annotation, classification and KEGG signaling pathway analysis were performed. The results showed that out of 3206 genes detected in silk gland after phoxim exposure, 270 were differentially expressed significantly, including 249 up-regulated genes and 21 down-regulated genes. These differentially expressed genes related to apoptosis, detoxification and protein degradation were selected. Using qRT-PCR, the expression levels of 9 genes involved in apoptosis, detoxification and protein degradation were validated. In addition, the expression profiles of three related fibroin synthesis genes (Fib-H, Fib-L and P25) were analyzed. Our results showed that phoxim exposure induced apoptosis of silk gland cells and inhibition of fibroin synthesis. This may be the cause of deficient silkworm cocooning., (Copyright © 2013. Published by Elsevier Inc.)
- Published
- 2013
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26. 4,9,12,15-Tetra-oxa-3,5,8,10,14,16-hexa-aza-tetra-cyclo-[11.3.0.0.0]hexa-deca-1(16),2,5,7,10,13-hexaen-3-ium-3-olate monohydrate.
- Author
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Zhou YS, Wang BZ, and Xu KZ
- Abstract
The organic mol-ecule in the title monohydrate, C(6)N(6)O(5)·H(2)O, presents an almost planar configuration, the greatest deviation from the least-squares plane through the atoms being 0.061 (1) Å for the O atom within the seven-membered ring. Each water H atom is bifurcated, one forming two O-H⋯N hydrogen bonds and the other forming O-H⋯N,O hydrogen bonds. The result of the hydrogen bonding is the formation of supra-molecular layers with a zigzag topology that stack along [001].
- Published
- 2012
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27. Non-isothermal decomposition kinetics, heat capacity and thermal safety of 37.2/44/16/2.2/0.2/0.4-GAP/CL-20/Al/N-100/PCA/auxiliaries mixture.
- Author
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Zhang JQ, Gao HX, Ji TZ, Xu KZ, and Hu RZ
- Subjects
- Kinetics, Hot Temperature, Safety
- Abstract
The specific heat capacity (C(p)) of 37.2/44/16/2.2/0.2/0.4-GAP/CL-20/Al/N-100/PCA/auxiliaries mixture was determined with the continuous C(p) mode of microcalorimeter. The equation of C(p) with temperature was obtained. The standard molar heat capacity of GAP/CL-20/Al/N-100/PCA/auxiliaries mixture was 1.225 J mol(-1)K(-1) at 298.15K. With the help of the peak temperature (T(p)) from the non-isothermal DTG curves of the mixture at different heating rates (β), the apparent activation energy (E(k) and E(o)) and pre-exponential constant (A(K)) of thermal decomposition reaction obtained by Kissinger's method and Ozawa's method. Using density (ρ) and thermal conductivity (λ), the decomposition heat (Q(d), taking half-explosion heat), Zhang-Hu-Xie-Li's formula, the values (T(e0) and T(p0)) of T(e) and T(p) corresponding to β → 0, thermal explosion temperature (T(be) and T(bp)), adiabatic time-to-explosion (t(TIad)), 50% drop height (H(50)) of impact sensitivity, and critical temperature of hot-spot initiation (T(cr,hot spot)) of thermal explosion of the mixture were calculated. The following results of evaluating the thermal safety of the mixture were obtained: T(be) = 441.64K, T(bp) = 461.66 K, t(Tlad) = 78.0 s (n = 2), t(Tlad) = 74.87 s (n = 1), t(Tlad) = 71.85 s (n = 0), H(50) = 21.33 cm., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2011
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28. Thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates of BTATz-CMDB propellant.
- Author
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Yi JH, Zhao FQ, Wang BZ, Liu Q, Zhou C, Hu RZ, Ren YH, Xu SY, Xu KZ, and Ren XN
- Subjects
- Kinetics, Safety, Temperature, Explosive Agents chemistry, Tetrazoles chemistry, Thermodynamics
- Abstract
The composite modified double base (CMDB) propellants (nos. RB0601 and RB0602) containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz) without and with the ballistic modifier were prepared and their thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates were investigated. The results show that there are three mass-loss stages in TG curve and two exothermic peaks in DSC curve for the BTATz-CMDB propellant. The first two mass-loss stages occur in succession and the temperature ranges are near apart, and the decomposition peaks of the two stages overlap each other, inducing only one visible exothermic peak appear in DSC curve during 350-550 K. The reaction mechanisms of the main exothermal decomposition processes of RB0601 and RB0602 are all classified as chemical reaction, the mechanism functions are f(alpha)=(1-alpha)(2), and the kinetic equations are dalpha/dt = 10(19.24)(1-alpha)(2)e(-2.32x10(4)/T) and dalpha/dt = 10(20.32)(1-alpha)(2)e(-2.32x10(4)/T). The thermal safety evaluation on the BTATz-CMDB propellants was obtained. With the substitution of 26% RDX by BTATz and with the help of the ballistic modifier in the CMDB propellant formulation, the burning rate can be improved by 89.0% at 8 MPa and 47.1% at 22 MPa, the pressure exponent can be reduced to 0.353 at 14-20 MPa., (Copyright 2010 Elsevier B.V. All rights reserved.)
- Published
- 2010
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29. Pomegranate flower ameliorates fatty liver in an animal model of type 2 diabetes and obesity.
- Author
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Xu KZ, Zhu C, Kim MS, Yamahara J, and Li Y
- Subjects
- Animals, Carcinoma, Hepatocellular metabolism, Cell Line, Tumor, Diabetes Mellitus, Experimental complications, Fatty Liver etiology, Fatty Liver genetics, Flowers, Gene Expression Regulation drug effects, Humans, Liver Function Tests, Liver Neoplasms metabolism, Male, Obesity complications, PPAR alpha drug effects, PPAR alpha genetics, RNA, Messenger drug effects, RNA, Messenger metabolism, Rats, Rats, Zucker, Diabetes Mellitus, Type 2 complications, Fatty Liver prevention & control, Lythraceae chemistry, Plant Extracts pharmacology
- Abstract
Aims of the Study: Fatty liver is the most common cause of abnormal liver function tests. We investigated the effect and its underlying mechanism of pomegranate flower (PGF), a traditional antidiabetic medicine, on fatty liver., Materials and Methods: At the endpoint of treatment of male Zucker diabetic fatty (ZDF) rats with PGF extract (500 mg/kg, p.o. x 6 weeks), liver weight index, hepatic lipid contents (enzymatic colorimetric methods) and droplet accumulation (Oil Red O staining) were determined. Gene profiles (RT-PCR) were analyzed in the liver of ZDF rats and in human liver-derived HepG2 cell line., Results: PGF-treated ZDF rats showed reduced ratio of liver weight to tibia length, hepatic triglyceride contents and lipid droplets. These effects were accompanied by enhanced hepatic gene expression of peroxisome proliferator-activated receptor (PPAR)-alpha, carnitine palmitoyltransferase-1 and acyl-CoA oxidase (ACO), and reduced stearoyl-CoA desaturase-1. In contrast, PGF showed minimal effects on expression of genes responsible for synthesis, hydrolysis or uptake of fatty acid and triglycerides. PGF treatment also increased PPAR-alpha and ACO mRNA levels in HepG2 cells., Conclusion: Our findings suggest that this Unani medicine ameliorates diabetes and obesity-associated fatty liver, at least in part, by activating hepatic expression of genes responsible for fatty acid oxidation.
- Published
- 2009
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30. Inhibition of voluntary saccadic eye movement commands by abrupt visual onsets.
- Author
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Edelman JA and Xu KZ
- Subjects
- Adult, Attention physiology, Discrimination Learning, Female, Humans, Male, Orientation, Photic Stimulation methods, Probability, Reaction Time physiology, Time Factors, Young Adult, Inhibition, Psychological, Saccades physiology, Vision, Ocular physiology, Visual Fields physiology
- Abstract
Saccadic eye movements are made both to explore the visual world and to react to sudden sensory events. We studied the ability for humans to execute a voluntary (i.e., nonstimulus-driven) saccade command in the face of a suddenly appearing visual stimulus. Subjects were required to make a saccade to a memorized location when a central fixation point disappeared. At varying times relative to fixation point disappearance a visual distractor appeared at a random location. When the distractor appeared at locations distant from the target virtually no saccades were initiated in a 30- to 40-ms interval beginning 70-80 ms after appearance of the distractor. If the distractor was presented slightly earlier relative to saccade initiation then saccades tended to have smaller amplitudes, with velocity profiles suggesting that the distractor terminated them prematurely. In contrast, distractors appearing close to the saccade target elicited express saccade-like movements 70-100 ms after their appearance, although the saccade endpoint was generally scarcely affected by the distractor. An additional experiment showed that these effects were weaker when the saccade was made to a visible target in a delayed task and still weaker when the saccade itself was made in response to the abrupt appearance of a visual stimulus. A final experiment revealed that the effect is smaller, but quite evident, for very small stimuli. These results suggest that the transient component of a visual response can briefly but almost completely suppress a voluntary saccade command, but only when the stimulus evoking that response is distant from the saccade goal.
- Published
- 2009
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31. [Research on shortwave NIR spectroscopy and its application to in situ flammable liquid detection].
- Author
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Wu J, Du ZH, Liu J, and Xu KZ
- Abstract
Fast, accurate and highly effective detection in situ was important to the control of illegal transportation and the use of liquid state dangerous goods. The present article used the strong penetrability of the shortwave near-infrared ray to the packing material and liquid and measured the absorption spectra of some flammable liquids such as the absolute ethyl alcohol, absolute methanol, ammonia, turpentine, gasoline, diesel oil, petroleum etc and the partial liquors in the short wavelength region of NIR (667-1000 nm). The primitive spectral data were standardized and compressed, and then, the characteristic wavelength of the absorption spectra was analyzed using the SPSS statistics software. A math model for flammable liquid distinction was established based on the designated characteristic wavelength and can correctly detect flammable liquid using the absorbency of 3 wavelengths (881, 935 and 981 nm). According to the above the authors may construct the inexpensive spectrum instrument to check the flammable liquid non-destructively in situ.
- Published
- 2008
32. Increased renal collagen cross-linking and lipid accumulation in nephropathy of Zucker diabetic fatty rats.
- Author
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Li Y, Qi Y, Kim MS, Xu KZ, Huang TH, Rong X, Murray M, and Yamahara J
- Subjects
- Animals, Collagen genetics, DNA Primers, Diabetes Mellitus, Type 1 genetics, Diabetes Mellitus, Type 1 metabolism, Diabetic Nephropathies genetics, Diabetic Nephropathies pathology, Gene Expression Profiling, Kidney anatomy & histology, Male, Organ Size, Rats, Rats, Zucker, Collagen metabolism, Cross-Linking Reagents metabolism, Diabetic Nephropathies metabolism, Kidney metabolism, Kidney pathology, Lipids physiology
- Abstract
Background: Zucker diabetic fatty (ZDF) rat is a genetic model of type 2 diabetes and obesity. The mechanism underlying nephropathy in ZDF rats, however, remains unclear., Methods: ZDF rats were compared to age-matched Zucker lean (ZL) rats. Physiological and blood biochemical parameters, renal glomerular cross-sectional area (hematoxylin-eosin staining), fibrosis (van Giesen staining), collagen composition (Sircol Collagen Assay), lipids (enzymatic method) and mRNA expression (RT-PCR) were determined., Results: ZDF rats showed an increase in renal-insoluble collagen content and the ratio of renal-insoluble to salt-soluble collagen (2- and 1.5-fold of the control animals). There were increases in renal glomerulosclerosis and interstitial fibrosis in ZDF rats (increased to 2-fold) in the glomerular mesangium and tubulointerstitium, and increased glomerular area. Renal triglyceride accumulated to greater than 2-fold of those levels in ZL rats. These changes were accompanied by hypoalbuminemia, and elevated plasma blood urea nitrogen and uric acid levels. Gene profiling showed increased expression of transcripts encoding the glomerulosclerotic mediator collagens I and IV, plasminogen activator inhibitor-1, transforming growth factor-beta1, and angiotensin II type 1 receptor in ZDF rat kidney. Moreover, renal expression of mRNAs encoding sterol regulatory element-binding protein-1, a nuclear transcription factor that activates genes involved in fatty acid synthesis, and acetyl-CoA carboxylase, a key enzyme that mediates fatty acid synthesis, was increased in ZDF rats., Conclusions: Our findings suggest that dysregulated gene expression may result in increased renal collagen cross-linking and lipid accumulation, that may be associated with development of nephropathy in the animal model of type 2 diabetes and obesity.
- Published
- 2008
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33. Valence electronic structures of CH2BrCl and CF2BrCl: binding energy spectra and electron momentum distributions.
- Author
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Li ZJ, Shan X, Yang XF, Chen LQ, Xu KZ, and Chen XJ
- Abstract
The binding energy spectra (BES) of valence shells of CH2BrCl and CF2BrCl have been measured at a series of different azimuthal angles by an (e, 2e) electron momentum spectrometer employing noncoplanar symmetric geometry at an impact energy of 1200 eV plus binding energy. The experimental momentum profiles (XMPs) are extracted from the sequential BES and compared with the theoretical ones calculated by using Hartree-Fock (HF) and density functional theory (DFT-B3LYP) calculations with 6-311G, 6-311++G**, and aug-cc-pVTZ basis sets. In general, the DFT-B3LYP calculations using the larger basis sets 6-311++G** and aug-cc-pVTZ describe the XMPs well for both molecules. Moreover, the pole strengths of main ionizations from the inner valence orbitals 2a', 3a', and 1a' of CH2BrCl are determined, and the controversial ordering of two outer valence orbitals 3a' ' and 6a' of CF2BrCl has also been assigned unambiguously.
- Published
- 2008
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34. Endosperm-specific hypomethylation, and meiotic inheritance and variation of DNA methylation level and pattern in sorghum (Sorghum bicolor L.) inter-strain hybrids.
- Author
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Zhang MS, Yan HY, Zhao N, Lin XY, Pang JS, Xu KZ, Liu LX, and Liu B
- Subjects
- Azacitidine pharmacology, Hybridization, Genetic, Inheritance Patterns, Meiosis genetics, Plant Leaves drug effects, Plant Leaves genetics, Plant Leaves metabolism, RNA metabolism, Sorghum embryology, Sorghum metabolism, Stochastic Processes, DNA Methylation, Epigenesis, Genetic, Seeds genetics, Sorghum genetics
- Abstract
Understanding dynamics and inheritance of DNA methylation represents important facets for elucidating epigenetic paradigms in plant development and evolution. Using four sets of sorghum (Sorghum bicolor L.) inter-strain hybrids and their inbred parents, the developmental stability and inheritance of cytosine methylation in two tissues, leaf and endosperm, by MSAP analysis were investigated. It was found that in all lines (inbred and hybrid) studied, endosperm exhibited a markedly reduced level of full methylation of the external cytosine or both cytosines at the CCGG sites relative to leaf, which caused a variable reduction in the estimated total methylation level in endosperm by 6.89-19.69% (11.47% on average). For both tissues, a great majority of cytosine methylation profiles transmitted to F1 hybrids, however, from 1.69 to 3.22% of the profiles showed altered patterns in hybrids. Both inherited and altered methylation profiles can be divided into distinct groups, and their frequencies are variable among the cross-combinations, and between the two tissues. The variations in methylation level and pattern detected in the hybrids were not caused by parental heterozygosity, and they could be either non-random or stochastic among hybrid individuals. Homology analysis of isolated bands that showed endosperm-specific hypomethylation or variation in hybrids indicated that diverse sequences were involved, including known-function cellular genes and mobile elements. RT-PCR analysis of six genes representing endosperm-specific hypomethylation in MSAP profiles indicated that all showed higher expression in endosperm than in leaf, suggesting involvement of methylation state in regulating tissue-specific or tissue-biased expression in sorghum. Analysis on leaf-RNA from 5-azacytidine-treated plants further corroborated this possibility.
- Published
- 2007
- Full Text
- View/download PDF
35. High resolution electron momentum spectroscopy of dichlorodifluoromethane: unambiguous assignments of outer valence molecular orbitals.
- Author
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Shan X, Chen XJ, Zhou LX, Li ZJ, Liu T, Xue XX, and Xu KZ
- Abstract
On account of controversial orbital assignment that appeared in previous works, [J. Chem. Phys. 120, 7933 (2004), and references therein] high resolution electron momentum spectroscopy (EMS) measurements on dichlorodifluoromethane has been carried out using a newly developed high resolution energy-momentum dispersive multichannel spectrometer employing asymmetric noncoplanar geometry at an impact energy of 2500 eV plus binding energy. Four resolved structures and two shoulders were obviously observed in high resolution binding energy spectrum in energy range covering eight outermost valence orbitals, whereas only two broad lobes were resolved in previous EMS studies [J. Chem. Phys. 120, 7933 (2004); Chin. Phys. 14, 2467 (2005)]. The ordering of these orbitals was reassigned unambiguously by simple comparison of experimental momentum distributions with theoretical ones.
- Published
- 2006
- Full Text
- View/download PDF
36. Optical oscillator strengths for valence-shell and Br-3d inner-shell excitations of HCl and HBr.
- Author
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Li WB, Zhu LF, Yuan ZS, Liu XJ, and Xu KZ
- Abstract
Absolute optical oscillator strength density spectra for valence-shell excitations of HCl and HBr, as well as for Br-3d inner-shell excitations of HBr, have been determined by high-resolution electron-energy-loss-spectroscopy method in the dipole limit. Absolute optical oscillator strengths for the discrete transitions of HCl and HBr are reported and compared with the previous results determined by the photoabsorption method.
- Published
- 2006
- Full Text
- View/download PDF
37. Electron-impact excitation of D1delta <-- X1sigma+ in carbon monoxide.
- Author
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Zhu LF, Ren HF, Liu XJ, Yuan ZS, Wu Y, and Xu KZ
- Abstract
The dipole-forbidden transition of D1delta <-- X1sigma+ of CO has been observed by a fast electron-energy-loss spectrometer at a large scattering angle of 7 degrees and with an energy resolution of 60 meV. The energy levels and the relative intensity distribution of D1delta, v'=9-25 have been determined, most of the results are reported for the first time.
- Published
- 2005
- Full Text
- View/download PDF
38. Dynamical correlation in double excitations of helium studied by high-resolution and angular-resolved fast-electron energy-loss spectroscopy in absolute measurements.
- Author
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Liu XJ, Zhu LF, Yuan ZS, Li WB, Cheng HD, Huang YP, Zhong ZP, Xu KZ, and Li JM
- Abstract
The momentum transfer dependence of fundamental double excitation processes of helium is studied by absolute measurements using an angular resolved fast-electron energy loss spectrometer with high energy resolution. It elucidates the dynamical correlations, in terms of internal correlation quantum numbers, K, T, and A. The Fano profile parameters q, f(a), rho2, f, and S of doubly excited states (2)(1,0)+2 (1)S(e), (2)(1,0)+2 (1)D(e), and (2)(0,1)+2 (1)P(o) are reported as functions of momentum transfer K2. Qualitative analysis is given for the states of (2)(-1,0)+2 (1)S(e) and (2)(1,0)+2 (1)S(e).
- Published
- 2003
- Full Text
- View/download PDF
39. Absolute generalized oscillator strengths of 4s, 4s', 4p+4p' excitations of argon determined by the angle-resolved electron-energy-loss spectrometer.
- Author
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Ji Q, Wu SL, Feng RF, Zhang XJ, Zhu LF, Zhong ZP, Xu KZ, and Zheng Y
- Published
- 1996
- Full Text
- View/download PDF
40. Absolute generalized oscillator strengths of 2 1S and 2 1P excitations of helium measured by angle-resolved electron-energy-loss spectroscopy.
- Author
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Xu KZ, Feng RF, Wu SL, Ji Q, Zhang XJ, Zhong ZP, and Zheng Y
- Published
- 1996
- Full Text
- View/download PDF
41. Electron-impact study in valence and autoionization resonance regions of argon.
- Author
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Wu SL, Zhong ZP, Feng RF, Xing SL, Yang BX, and Xu KZ
- Published
- 1995
- Full Text
- View/download PDF
42. Absolute total-cross-section measurements for intermediate-energy electron scattering on C2H2 and CO.
- Author
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Xing SL, Shi QC, Chen XJ, Xu KZ, Yang BX, Wu SL, and Feng RF
- Published
- 1995
- Full Text
- View/download PDF
43. Emission spectrum of silicon in the region of anomalous dispersion.
- Author
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Hao Ly, Yang Bx, Xu Kz, Fang Zg, Xu Xl, Chen J, and Chen Yz
- Published
- 1993
- Full Text
- View/download PDF
44. Angular-distribution measurement of emitted photons in the fast-electron impact of sodium.
- Author
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Yang Bx, Xu Kz, Hao Ly, and Xu Xl
- Published
- 1989
- Full Text
- View/download PDF
45. [One stage resection of esophageal cancer and pulmonary bulla--a report of three patients].
- Author
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Ma Q, Cao XF, and Xu KZ
- Subjects
- Cardia, Esophageal Neoplasms complications, Humans, Lung Diseases complications, Male, Methods, Middle Aged, Stomach Neoplasms complications, Esophageal Neoplasms surgery, Lung Diseases surgery, Stomach Neoplasms surgery
- Abstract
Since 1982, three patients with esophageal cancer complicated with pulmonary bullae have been treated by operation on the esophagus and lung in one performance: In all the patients, the bullae were on the same side of the operation. The esophageal or cardiac cancer was resected first, then the bulla was treated. The site of esophago-gastric anastomosis was reinforced by the greater omentum. For mid-upper esophageal cancer, cervical anastomosis was done in order to avoid infection or leakage. In the third patient, pyopneumothorax occurred after wedge resection of a large bulla in the right upper lung and the surrounding tissues. The patient survived after timely drainage and medical management. The extent of resection for pulmonary bulla (bulla, segment or lobe) depends on the location, shape, size and number of the bullae and the pathological change in the surrounding tissues. We suggest that the indications: Cardio-pulmonary functions of the patient be stage II or better, even with mild emphysema so as they can tolerate anesthesia and surgery. Pulmonary function can be compensated after the lesion is removed, otherwise it is taken as a contraindication. The one stage removal of two foci makes it possible to avoid postoperative complications.
- Published
- 1986
46. Experimental verification of C
- Author
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Xu Kz, Bing-xin Yang, Fu-yun Xi, Wei-ming Wu, and Lu-yan Hao
- Published
- 1988
- Full Text
- View/download PDF
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