43 results on '"Guo GJ"'
Search Results
2. Simulation of Synchronous Motor Power driven System for EPS Based on SVPWM-DTC
- Author
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Ye, XueFeng, primary, Fang, ZuHua, primary, Sun, Ying, primary, Guo, GJ, primary, and Wang, Jiale, primary
- Published
- 2016
- Full Text
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3. Simultaneous Elastic Recoil Detection Analysis of H and OtherElements in Foils.
- Author
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Lu LX Xiu-Qin, Zhou ZP Ping, Guo GJ Ji-Yu, Zhang ZX Xin, Zhao ZK Kui, Ni NM Mei-Nan, Sui SL Li, Mei MJ Jun-Ping, and Liu LJ Jian-Cheng
- Published
- 2005
4. Global research landscape of Peutz-Jeghers syndrome and successful endoscopic management of intestinal intussusception in patients with recurrent laparotomies.
- Author
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Sun Q, Wang XY, Guo GJ, Wang L, Meng LM, Guo YF, Sun T, and Ning SB
- Abstract
Background: Peutz-Jeghers syndrome (PJS) has brought significant physical, psychological and economic burdens on the patients and their families due to its early onset, diagnostic and therapeutic challenges and increased recurrence risk., Aim: To explore the current research status and emerging hotspots of PJS., Methods: Studies on PJS published during 1994-2023 were gathered based on Web of Science Core Collection. Additionally, a case of PJS-induced intestinal intussusception, successfully treated with endoscopic methods despite three laparotomies, was highlighted. Comprehensive bibliometric and visual analysis were conducted with VOSviewer, R and CiteSpace., Results: Altogether 1760 studies were identified, indicating a steady increase in the publication number. The United States had the highest influence, whereas the University of Helsinki emerged as the leading institution, and Aaltonen LA from the University of Helsinki was the most prolific author. Cancer Research, Oncogene and Endoscopy were the top three journals based on H-index. Keyword burst direction analysis revealed that "cancer risk", "management", "surveillance" and "familial pancreatic cancer" were the potential hotspots for investigation. Additionally, "early detection", "capsule endoscopy", "clinical management", "double-balloon endoscopy", "familial pancreatic cancer" and "molecular genetic basis" were identified as the key clusters of co-cited references. Endoscopic polypectomy remained effective on resolving intestinal intussusception in patients who underwent three previous laparotomies., Conclusion: In the last three decades, global publications related to PJS show a steadily increasing trend in number. Endoscopic management is currently a research hotspot., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict of interest., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)
- Published
- 2024
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5. Gut microbiome and metabolic-associated fatty liver disease: Current status and potential applications.
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Guo GJ, Yao F, Lu WP, and Xu HM
- Abstract
Metabolic-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases worldwide. In recent years, the occurrence rate of MAFLD has been on the rise, mainly due to lifestyle changes, high-calorie diets, and imbalanced dietary structures, thereby posing a threat to human health and creating heavy social and economic burdens. With the development of 16S sequencing and integrated multi-omics analysis, the role of the gut microbiota (GM) and its metabolites in MAFLD has been further recognized. The GM plays a role in digestion, energy metabolism, vitamin synthesis, the prevention of pathogenic bacteria colonisation, and immunoregulation. The gut-liver axis is one of the vital links between the GM and the liver. Toxic substances in the intestine can enter the liver through the portal vascular system when the intestinal barrier is severely damaged. The liver also influences the GM in various ways, such as bile acid circulation. The gut-liver axis is essential in maintaining the body's normal physiological state and plays a role in the onset and prognosis of many diseases, including MAFLD. This article reviews the status of the GM and MAFLD and summarizes the GM characteristics in MAFLD. The relationship between the GM and MAFLD is discussed in terms of bile acid circulation, energy metabolism, micronutrients, and signalling pathways. Current MAFLD treatments targeting the GM are also listed., Competing Interests: Conflict-of-interest statement: The authors declare that they have no competing interests., (©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.)
- Published
- 2023
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6. [A case of primary cardiac lymphoma diagnosed by intravenous right atrial catheter forceps biopsy].
- Author
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Chen K, Chang L, Chen JZ, Wei X, Guo GJ, Lu JR, Wang K, Kang LN, Wang L, and Xu B
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- Humans, Biopsy, Surgical Instruments, Catheters, Heart Atria, Lymphoma pathology
- Published
- 2022
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7. Analgesic Effects of Two Types of Spinal Manipulation in Acute Lumbar Radiculopathy Model Rats.
- Author
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Han L, Zhao P, Han X, Wei J, Wang F, Li Y, and Guo GJ
- Subjects
- Animals, Male, Nucleus Pulposus transplantation, Pain, Rats, Rats, Sprague-Dawley, Transplantation, Autologous, Analgesia methods, Manipulation, Spinal, Radiculopathy therapy
- Abstract
Objective: To compare the analgesic effects of two types of spinal manipulation (SM) in acute lumbar radiculopathy (ALR) model rats induced by self-transplantation of autologous nucleus pulposus (ANP), and clarify the therapeutic mechanism., Methods: Totally 108 male Sprague-Dawley rats were randomly divided into 6 groups by a random number table (18 rats in each group), including a blank group with no interference, a sham operation group with a surgery by making a local soft tissue incision on the left side of L5-6 vertebral segment, a model group with ALR of L5 extraforaminal nerve by ANP self-transplantation without other interference, a sham manipulation (SMA) group with simulating physical rotation, as well as a mobilization (MOB) group with simulating low-velocity and variable-amplitude rotation and a manipulation (MAN) group with simulating high-velocity and low-amplitude rotation. The interventions in SMA, MOB, and MAN groups started 1 day after modeling followed by another 5 treatments at days 3, 5, 8, 10 and 12. Rats in the other 3 groups did not receive any special intervention. Behavioral pain tests of 50% mechanical pain withdrawal threshold (50% PWT) and paw withdrawal latency (PWL) were conducted 1 day before operation followed by another 10 tests on days 1-7, 10, 12 and 14. Immunohistochemical expression of nitric oxide synthase (NOS) was investigated on days 5 and 12 after operation., Results: After 3 experimental SM interventions, 50% PWT and PWL were higher in the MAN group than the SMA group on days 6 and 7, and higher on days 10, 12 and 14 postoperatively (P<0.05 or P<0.01), while the same indices were significantly higher in the MOB group than MAN group on days 1-4 (P<0.05 or P<0.01). The expression of NOS was lower in the MAN and MOB groups than SMA group on day 12 postoperatively (P<0.01)., Conclusions: Both manipulation and mobilization produced better results than sham interference in relieving pain by reducing neuroinflammation possibly. At the early period, compared with manipulation, mobilization presented less sensitive response to pain until later visit. SM may inhibit the overexpression of NOS, thereby alleviating severe radiculopathy., (© 2021. The Chinese Journal of Integrated Traditional and Western Medicine Press and Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2022
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8. [Efficacy and safety of black tomato concentrate in the treatment of erectile dysfunction: A prospective randomized controlled open trial].
- Author
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Wang Y, Li GB, Guo GJ, Wang GR, Xu H, Bo XB, Guo YL, Wang ZP, and Donf ZL
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- Male, Humans, Penile Erection, Capsules therapeutic use, Prospective Studies, Treatment Outcome, Double-Blind Method, Erectile Dysfunction drug therapy, Erectile Dysfunction etiology, Solanum lycopersicum
- Abstract
Objective: To evaluate the efficacy and safety of black tomato concentrate (BTC), which is rich in polyphenols, in the treatment of ED., Methods: We conducted a prospective randomized open clinical study of 150 ED patients from December 2018 to February 2020, and treated the them with placebo (n = 50), BTC (n = 50) and Compound Xuanju Capsules (CXC) (n = 50), respectively, all for 8 weeks. Before and at 4 and 8 weeks after treatment, we obtained the scores of the patients on IIEF-5, Erection Hardness Score (EHS), Sexual Encounter Profile (SEP-2,3) and General Assessment Questionnaire (GAQ-1,2), related biochemical indexes and the T level, followed by comparison among the three groups., Results: Totally, 120 of the patients completed the clinical trial, 37 in the placebo, 43 in the BTC and 40 in the CXC group. There were no statistically significant differences among the placebo, BTC and CXC groups in the baseline scores on IIEF-5 (12.03 �� 3.50 vs 11.70 �� 3.80 vs 11.42 �� 3.82), EHS, and SEP-2,3 (P > 0.05). At 8 weeks after treatment, the patients in the BTC group showed significant improvement in IIEF-5 (15.67 �� 3.63), EHS, SEP-2,3 and GAQ-1 positive response compared with those in the placebo group (P < 0.05) and similar improvement to that in the CXC group in IIEF-5 (15.67 �� 3.63 vs 15.65 �� 3.87), EHS, SEP-2,3 and GAQ-1,2 (P > 0.05). No statistically significant differences were observed in the incidence of adverse reactions among the placebo, BTC and CXC groups (4.7% vs 2.7% vs 5.0%, P > 0.05), and the symptoms were significantly relieved in the BTC group after change of the administration time to after meal., Conclusion: Black tomato concentrate is comparable to Compound Xuanju Capsules and better than placebo (P < 0.05) in improving the IIEF-5, EHS and SEP-2,3 scores of ED patients. And, with a high safety, it can be used as an alternative treatment of ED.
- Published
- 2022
9. Characterization of short-chain fatty acids in patients with ulcerative colitis: a meta-analysis.
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Xu HM, Zhao HL, Guo GJ, Xu J, Zhou YL, Huang HL, and Nie YQ
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- Butyrates, Fatty Acids, Volatile, Healthy Volunteers, Humans, Propionates, Colitis, Ulcerative
- Abstract
Background: Studies investigating the changes in short-chain fatty acids (SCFAs) in patients with ulcerative colitis (UC) have yielded inconsistent results. We performed a meta-analysis of studies that investigated the alterations in different SCFAs among UC patients to assess their role in the development of UC., Methods: Three databases were searched for relevant studies published as of April 2021. Results are presented as standardized mean difference (SMD) with 95% confidence interval (95% CI)., Results: Eleven studies were included in the meta-analysis. Compared to healthy subjects, UC patients had significantly lower concentrations of total SCFAs (SMD = - 0.88, 95%CI - 1.44, - 0.33; P < 0.001), acetate (SMD = - 0.54, 95% CI - 0.91, - 0.17; P = 0.004), propionate, (SMD = - 0.37, 95% CI - 0.66, - 0.07; P = 0.016), and valerate (SMD = - 0.91, 95% CI - 1.45, - 0.38; P < 0.001). On subgroup analysis based on disease status, patients with active UC had reduced concentrations of acetate (SMD = - 1.83, 95% CI - 3.32, - 0.35; P = 0.015), propionate (SMD = - 2.51, 95% CI - 4.41, - 0.61; P = 0.009), and valerate (SMD = - 0.91, 95% CI - 1.45, - 0.38; P < 0.001), while UC patients in remission had similar concentrations with healthy subjects. Patients with active UC had lower butyrate level (SMD = - 2.09, 95% CI - 3.56, - 0.62; P = 0.005) while UC patients in remission had higher butyrate level (SMD = 0.71, 95% CI 0.33, 1.10; P < 0.001) compared with healthy subjects., Conclusion: UC patients had significantly decreased concentrations of total SCFAs, acetate, propionate, and valerate compared with healthy subjects. In addition, inconsistent changes of certain special SCFAs were observed in UC patients with different disease status., (© 2022. The Author(s).)
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- 2022
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10. Open questions on methane hydrate nucleation.
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Guo GJ and Zhang Z
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- 2021
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11. Comment on "Iterative Cup Overlapping: An Efficient Identification Algorithm for Cage Structures of Amorphous Phase Hydrates".
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Zhang Z and Guo GJ
- Published
- 2021
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12. Localization of Cell Receptor-Related Genes of SARS-CoV-2 in the Kidney through Single-Cell Transcriptome Analysis.
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Chen QL, Li JQ, Xiang ZD, Lang Y, Guo GJ, and Liu ZH
- Abstract
Background: The new coronavirus (SARS-CoV-2), which has been responsible for the recent coronavirus disease 2019 (COVID-19) pandemic, uses the cell receptor angiotensin converting enzyme-2 (ACE2) for entry and the serine protease TMPRSS2 for spike (S) protein priming. Meanwhile, the presence of B
0 AT1 (SLC6A19) may prevent TMPRSS2 from accessing the cutting position on ACE2. Identifying the expression of these cell receptor-related genes of SARS-CoV-2 is critical for understanding the pathogenesis of SARS-CoV-2 in various tissues, especially in the kidney., Methods: The single-cell transcription datasets of the human cell landscape (HCL) and other relevant single-cell transcription databases were used to analyze the expression of ACE2, TMPRSS2, and SLC6A19 in various organs and tissues, but mainly in the kidney., Results: ACE2 was significantly expressed in the S1, S2, and S3 segments of proximal tubule (PT) cells. TMPRSS2 was widely expressed in several renal tubule populations extending from the PT cells to the collection system cell type, of which intercalated cells and the distal convoluted tubule cells showed more significant expression than PT cells. Unexpectedly, although expressed on various renal tubule populations, SLC6A19 was mainly enriched in PT cells, in line with ACE2 expression. Although alveolar-type (AT) 2 cells of the lung and intestinal epithelial cells expressed ACE2 as well as PT cells, AT 2 cells significantly expressed TMPRSS2 but not SLC6A19, while all 3 genes were significantly expressed in intestinal epithelial cells., Conclusions: ACE2 was widely expressed in specific cell subgroups of various human tissues, especially in intestinal epithelial cells, kidney PT cells, and also AT 2 cells of the lung. These 3 types of cells demonstrated significant differences in the distribution of the cell receptor-related genes of SARS-CoV-2, which may indicate the diversity of cell surface structures and differences in the affinity between SARS-CoV-2 and cells., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2020 by S. Karger AG, Basel.)- Published
- 2020
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13. A new mixed inhibitor of adenosine deaminase produced by endophytic Cochliobolus sp. from medicinal plant seeds.
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Zhang XG, Sun QY, Tang P, Ma GY, Guo GJ, Guo SJ, and Ma XD
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- Adenosine Deaminase chemistry, Adenosine Deaminase metabolism, Adenosine Deaminase Inhibitors pharmacology, Ascomycota classification, Ascomycota genetics, Ascomycota isolation & purification, Binding Sites, Endophytes classification, Endophytes genetics, Endophytes isolation & purification, Humans, Magnetic Resonance Spectroscopy, Molecular Docking Simulation, Neoplasms drug therapy, Neoplasms enzymology, Seeds microbiology, Adenosine Deaminase Inhibitors chemistry, Ascomycota chemistry, Endophytes chemistry, Plants, Medicinal microbiology
- Abstract
Medicinal plants have been studied for potential endophytic interactions and numerous studies have provided evidence that seeds harbor diverse microbial communities, not only on their surfaces but also within the embryo. Adenosine deaminase (ADA) is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Therefore, in this study, 20 types of medicinal plant seeds were used to screen endophytic fungi with tissue homogenate and streak. In addition, 128 morphologically distinct endophyte strains were isolated and their ADA inhibitory activity determined by a spectrophotometric assay. The strain with the highest inhibitory activity was identified as Cochliobolus sp. Seven compounds were isolated from the strain using a chromatography method. Compound 3 showed the highest ADA inhibitory activity and was identified as 5-hydroxy-2-hydroxymethyl-4H-pyran-4-one, based on the results of 1H and 13C NMR spectroscopy. The results of molecular docking suggested that compound 3 binds to the active site and the nonspecific binding site of the ADA. Furthermore, we found that compound 3 is a mixed ADA inhibitor. These results indicate that endophytic strains are a promising source of ADA inhibitors and that compound 3 may be a superior source for use in the preparation of biologically active ADA inhibitor compounds used to treat cancer.
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- 2020
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14. [Clinical application of common botanical preparations in the treatment of benign prostatic hyperplasia].
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Guo GJ and Mi J
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- Humans, Male, Quality of Life, Lower Urinary Tract Symptoms drug therapy, Phytotherapy, Plant Extracts therapeutic use, Prostatic Hyperplasia drug therapy
- Abstract
With the increasing incidence of BPH, lower urinary tract symptoms (LUTS) it induces seriously affect the quality of life of middle-aged and elderly patients. Botanical preparations have the advantages of easy availability, reliable efficacy and less adverse reactions for the treatment of BPH. Botanical preparations commonly used for this purpose include lycopene, saw palmetto fruit extract, Pygeumafricanum extract, urtica extract, and so on. This article reviews the action mechanisms and the latest clinical application of the above four botanical preparations in the treatment of BPH, aiming to provide some more evidence for the selection of botanical therapies for BPH and a wider clinical application of botanical preparations.
- Published
- 2020
15. [A case of ductus arteriosus occluder displacement].
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Wang QP, Fang AJ, Guo GJ, and Wang J
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- Cardiac Catheterization, Humans, Ductus Arteriosus, Ductus Arteriosus, Patent, Septal Occluder Device
- Published
- 2019
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16. Abnormal composition of gut microbiota contributes to delirium-like behaviors after abdominal surgery in mice.
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Zhang J, Bi JJ, Guo GJ, Yang L, Zhu B, Zhan GF, Li S, Huang NN, Hashimoto K, Yang C, and Luo AL
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- Animals, Biodiversity, Fecal Microbiota Transplantation, Germ-Free Life, Male, Mice, Inbred C57BL, Random Allocation, Abdomen surgery, Delirium microbiology, Gastrointestinal Microbiome, Postoperative Complications microbiology
- Abstract
Aims: Anesthesia and surgery can cause delirium-like symptoms postoperatively. Increasing evidence suggests that gut microbiota is a physiological regulator of the brain. Herein, we investigated whether gut microbiota plays a role in postoperative delirium (POD)., Methods: Mice were separated into non-POD and POD phenotypes after abdominal surgery by applying hierarchical clustering analysis to behavioral tests. Fecal samples were collected, and 16S ribosomal RNA gene sequencing was performed to detect differences in gut microbiota composition among sham, non-POD, and POD mice. Fecal bacteria from non-POD and POD mice were transplanted into antibiotics-induced pseudo-germ-free mice to investigate the effects on behaviors., Results: α-diversity and β-diversity indicated differences in gut microbiota composition between the non-POD and POD mice. At the phylum level, the non-POD mice had significantly higher levels of Tenericutes, which were not detected in the POD mice. At the class level, levels of Gammaproteobacteria were higher in the POD mice, whereas the non-POD mice had significantly higher levels of Mollicutes, which were not detected in the POD mice. A total of 20 gut bacteria differed significantly between the POD and non-POD mice. Interestingly, the pseudo-germ-free mice showed abnormal behaviors prior to transplant. The pseudo-germ-free mice that received fecal bacteria transplants from non-POD mice but not from POD mice showed improvements in behaviors., Conclusions: Abnormal gut microbiota composition after abdominal surgery may contribute to the development of POD. A therapeutic strategy that targets gut microbiota could provide a novel alterative for POD treatment., (© 2019 The Authors. CNS Neuroscience & Therapeutics Published by John Wiley & Sons Ltd.)
- Published
- 2019
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17. Reynoutria Japonica from Traditional Chinese Medicine: A Source of Competitive Adenosine Deaminase Inhibitors for Anticancer.
- Author
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Zhang XG, Ma GY, Kou F, Liu WJ, Sun QY, Guo GJ, Ma XD, Guo SJ, and Jian-Ning Z
- Subjects
- Drug Screening Assays, Antitumor, Humans, K562 Cells, Adenosine Deaminase Inhibitors pharmacology, Antineoplastic Agents pharmacology, Emodin pharmacology, Medicine, Chinese Traditional, Plant Extracts chemistry, Polygonaceae chemistry
- Abstract
Background: Adenosine deaminase (ADA) is an important enzyme in purine metabolism and is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Traditional Chinese Herbal Medicine (TCHM) is widely used alone or in combination with chemotherapy to treat cancer, due to its ability to deliver a broad variety of bioactive secondary metabolites as promising sources of novel organic natural agents., Objective: In the present study, 29 varieties of medicinal plants were screened for the presence of ADA inhibitors., Results: Extracts from Reynoutria japonica, Glycyrrhiza uralensis, Lithospermum erythrorhizon, Magnolia officinalis, Gardenia jasminoides, Stephania tetrandra, Commiphora myrrha, Raphanus sativus and Corydalis yanhusuo demonstrated strong ADA inhibition with rates greater than 50%. However, Reynoutria japonica possessed the highest ADA inhibitory activity at 95.26% and so was used in our study for isolating the ADA inhibitor to be further studied. Eight compounds were obtained and their structures were identified. The compound H1 had strong ADA inhibitory activity and was deduced to be emodin by 1H and 13C-NMR spectroscopic analysis with an IC50 of 0.629 mM. The molecular docking data showed that emodin could bind tightly to the active site of ADA. Our results demonstrated that emodin displayed a new biological activity which is ADA inhibitory activity with high cytotoxic activity against K562 leukemia cells. The bioactivity of cordycepin was significantly increased when used in combination with emodin., Conclusion: Emodin may represent a good candidate anti-cancer therapy and adenosine protective agent., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)
- Published
- 2019
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18. Does Local Structure Bias How a Crystal Nucleus Evolves?
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Hall KW, Zhang Z, Burnham CJ, Guo GJ, Carpendale S, English NJ, and Kusalik PG
- Abstract
The broad scientific and technological importance of crystallization has led to significant research probing and rationalizing crystal nucleation processes. Previous work has generally neglected the possibility of the molecular-level dynamics of individual crystal nuclei coupling to local structures. However, recent experimental work has conjectured that this can occur. Therefore, to address a deficiency in scientific understanding of crystallization, we have probed the nucleation of prototypical single and multicomponent crystals (specifically, ice and mixed gas hydrates). We establish that local structures can bias the evolution of nascent crystal phases on a nanosecond time scale by, for example, promoting the appearance or disappearance of specific crystal motifs and thus reveal a new facet of crystallization behavior. Moreover, we demonstrate structural biases are likely present during crystallization processes beyond ice and gas hydrate formation. Structurally biased dynamics are a lens for understanding existing computational and experimental results while pointing to future opportunities.
- Published
- 2018
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19. Bridging solution properties to gas hydrate nucleation through guest dynamics.
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Zhang Z, Kusalik PG, and Guo GJ
- Abstract
By investigating the aqueous solution properties of several hydrate guests with molecular simulations, we find that with increasing guest concentration, the guest's hydration shell becomes more ordered and the system entropy decreases. A common critical value of the self-diffusion coefficient of different guest molecules is identified, below which hydrates will nucleate very readily.
- Published
- 2018
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20. Effects of gas reservoir configuration and pore radius on shale gas nanoflow: A molecular dynamics study.
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Tian H, Guo GJ, Geng M, Zhang Z, Zhang M, and Gao K
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We calculated methane transport through cylindrical graphite nanopores in cyclical steady-state flows using non-equilibrium molecular dynamics simulations. First, two typical gas reservoir configurations were evaluated: open (OS) and closed (CS) systems in which pores connect to the gas reservoir without/with a graphite wall parallel to the gas flow. We found that the OS configuration, which is commonly used to study nanoflows, exhibited obvious size effects. Smaller gas reservoir cross-sectional areas were associated with faster gas flows. Because Knudsen diffusion and slip flow in pores are interrupted in a gas reservoir that does not have walls as constraints, OSs cannot be relied upon in cyclical nanoflow simulations. Although CSs eliminated size effects, they introduced surface roughness effects that stem from the junction surface between the gas reservoir and the pore. To obtain a convergent nanoflow, the length of a side of the gas reservoir cross-section should be at least 2 nm larger than the pore diameter. Second, we obtained methane flux data for various pore radii (0.5-2.5 nm) in CSs and found that they could be described accurately using the Javadpour formula. This is the first direct molecular simulation evidence to validate this formula. Finally, the radial density and flow-velocity distributions of methane in CS pores were analyzed in detail. We tested pores with a radius between 0.5 nm and 2.5 nm and determined that the maximum ratio (∼34%) of slip flow to overall flow occurred in the pore with a radius of 1.25 nm. This study will aid in the design of gas reservoir configurations for nanoflow simulations and is helpful in understanding shale gas nanoflows.
- Published
- 2018
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21. Identification of a New Uncompetitive Inhibitor of Adenosine Deaminase from Endophyte Aspergillus niger sp.
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Zhang XG, Liu JW, Tang P, Liu ZY, Guo GJ, Sun QY, and Yin JJ
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- Adenosine Deaminase chemistry, Adenosine Deaminase metabolism, Adenosine Deaminase Inhibitors metabolism, Aspergillus niger genetics, Aspergillus niger isolation & purification, Aspergillus niger metabolism, Cell Line, Endophytes genetics, Endophytes isolation & purification, Endophytes metabolism, Humans, Magnetic Resonance Spectroscopy, Molecular Structure, Adenosine Deaminase Inhibitors chemistry, Aspergillus niger chemistry, Endophytes chemistry, Plants microbiology
- Abstract
Adenosine deaminase (ADA) is an enzyme widely distributed from bacteria to humans. ADA is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Endophytes are endosymbionts, often bacteria or fungi, which live within plant tissues and internal organs or intercellular space. Endophytes have a broad variety of bioactive metabolites that are used for the identification of novel natural compounds. Here, 54 morphologically distinct endophyte strains were isolated from six plants such as Peganum harmala Linn., Rheum officinale Baill., Gentiana macrophylla Pall., Radix stephaniae tetrandrae, Myrrha, and Equisetum hyemale Linn. The isolated strains were used for the search of ADA inhibitors that resulted in the identification of the strain with the highest inhibition activity, Aspergillus niger sp. Four compounds were isolated from this strain using three-step chromatography procedure, and compound 2 was determined as the compound with the highest inhibition activity of ADA. Based on the results of
1 H and13 C NMR spectroscopies, compound 2 was identified as 3-(4-nitrophenyl)-5-phenyl isoxazole. We showed that compound 2 was a new uncompetitive inhibitor of ADA with high cytotoxic effect on HepG2 and SMCC-7721 cells (the IC50 values were 0.347 and 0.380 mM, respectively). These results suggest that endophyte strains serve as promising sources for the identification of ADA inhibitors, and compound 2 could be an effective drug in the cancer treatment.- Published
- 2018
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22. The effects of ice on methane hydrate nucleation: a microcanonical molecular dynamics study.
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Zhang Z and Guo GJ
- Abstract
Although ice powders are widely used in gas hydrate formation experiments, the effects of ice on hydrate nucleation and what happens in the quasi-liquid layer of ice are still not well understood. Here, we used high-precision constant energy molecular dynamics simulations to study methane hydrate nucleation from vapor-liquid mixtures exposed to the basal, prismatic, and secondary prismatic planes of hexagonal ice (ice Ih). Although no significant difference is observed in hydrate nucleation processes for these different crystal planes, it is found, more interestingly, that methane hydrate can nucleate either on the ice surface heterogeneously or in the bulk solution phase homogeneously. Several factors are mentioned to be able to promote the heterogeneous nucleation of hydrates, including the adsorption of methane molecules at the solid-liquid interface, hydrogen bonding between hydrate cages and the ice structure, the stronger ability of ice to transfer heat than that of the aqueous solution, and the higher occurrence probability of hydrate cages in the vicinity of the ice surface than in the bulk solution. Meanwhile, however, the other factors including the hydrophilicity of ice and the ice lattice mismatch with clathrate hydrates can inhibit heterogeneous nucleation on the ice surface and virtually promote homogeneous nucleation in the bulk solution. Certainly, the efficiency of ice as a promoter and as an inhibitor for heterogeneous nucleation is different. We estimate that the former is larger than the latter under the working conditions. Additionally, utilizing the benefit of ice to absorb heat, the NVE simulation of hydrate formation with ice can mimic the phenomenon of ice shrinking during the heterogeneous nucleation of hydrates and lower the overly large temperature increase during homogeneous nucleation. These results are helpful in understanding the nucleation mechanism of methane hydrate in the presence of ice.
- Published
- 2017
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23. Antitumor activity of a Rhodococcus sp. Lut0910 isolated from polluted soil.
- Author
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Zhang XG, Liu ZY, Liu JW, Zeng YL, Guo GJ, and Sun QY
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- Animals, Carcinoma, Hepatocellular pathology, Cell Extracts chemistry, Female, Hep G2 Cells, Humans, Liver Neoplasms pathology, Mice, RNA, Ribosomal, 16S genetics, Rhodococcus chemistry, Soil Pollutants chemistry, Uterine Cervical Neoplasms pathology, Xenograft Model Antitumor Assays, Carcinoma, Hepatocellular drug therapy, Cell Extracts administration & dosage, Liver Neoplasms drug therapy, Uterine Cervical Neoplasms drug therapy
- Abstract
The actinomycetes strain, lut0910, was isolated from polluted soil and identified as the Rhodococcus species with 99% similarity based on the sequence analysis of 16S recombinant DNA. The extract of this strain demonstrated in vivo and in vitro antitumor activity. The treatment of two human cancer cell lines, hepatocellular carcinoma HepG2 and cervical carcinoma Hela cells, with the lut0910 extract caused the delay in cell propagation in a dose-dependent manner with an IC
50 of 73.39 and 33.09 µg/mL, respectively. Also, the oral administration of lut0910 extract to the mice with a solid tumor resulted in the inhibition of tumor growth in comparison with a placebo group. The thymus and spleen indexes were significantly increased in mice groups treated with the lut0910 extract. The histopathological changes of the tumor tissues showed that there were massive necrotic areas in the tumor tissues after treatment with different doses of the lut0910 extract. Our result would provide a new way and potent source for development of new anticancer agent from the polluted environment.- Published
- 2017
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24. Choice and Hope.
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Law FM and Guo GJ
- Subjects
- Adolescent, Adult, Humans, Male, Surveys and Questionnaires, Taiwan, Treatment Outcome, Young Adult, Choice Behavior, Psychotherapy, Group methods, Reality Therapy methods, Substance-Related Disorders psychology, Substance-Related Disorders rehabilitation
- Abstract
Hope theory identifies goal, pathway, and agency as essential elements of hope that promote and maximize the effectiveness of treatment. Much significant evidence has indicated that hope is a strong predictor of substance involvement recovery. This study aimed to test the effectiveness of choice-based reality therapy in strengthening hope in recovery for women convicted of drug offences in Taiwan. The participants in the substance involvement treatment program were 44 incarcerated women convicted of drug offences, who were randomly selected and randomly assigned to equal-sized experimental and control groups. The results of the study, obtained by ANCOVA analysis, showed significant differences between the two groups in the posttest scores for sense of hope as measured in the subscales of goal setting and pursuing, adequate energy, and controlling pathway. The effect size values of the three variables suggested a moderate practical significance. The evidence provided in the present study indicates that, upon completion of the choice-based reality therapy for substance involvement, when compared with those who had not yet attended the program, Taiwanese women convicted of drug offences reported a significantly higher level of hope. Hope was measured by their ability in setting goals and overcoming obstacles and persistence in pursuing the goals they had set up, energy for recovery, and their capacity to set up pathways based on their goals. The findings highlight the value of choice-based reality therapy in enhancing hope of recovery for women convicted of drug offences.
- Published
- 2017
- Full Text
- View/download PDF
25. Single-cell analysis reveals a nestin + tendon stem/progenitor cell population with strong tenogenic potentiality.
- Author
-
Yin Z, Hu JJ, Yang L, Zheng ZF, An CR, Wu BB, Zhang C, Shen WL, Liu HH, Chen JL, Heng BC, Guo GJ, Chen X, and Ouyang HW
- Subjects
- Animals, Mice, Mice, Transgenic, Nestin genetics, Stem Cells cytology, Tendons cytology, Databases, Nucleic Acid, Gene Expression Regulation physiology, Nestin metabolism, Stem Cells metabolism, Tendons metabolism
- Abstract
The repair of injured tendons remains a formidable clinical challenge because of our limited understanding of tendon stem cells and the regulation of tenogenesis. With single-cell analysis to characterize the gene expression profiles of individual cells isolated from tendon tissue, a subpopulation of nestin
+ tendon stem/progenitor cells (TSPCs) was identified within the tendon cell population. Using Gene Expression Omnibus datasets and immunofluorescence assays, we found that nestin expression was activated at specific stages of tendon development. Moreover, isolated nestin+ TSPCs exhibited superior tenogenic capacity compared to nestin- TSPCs. Knockdown of nestin expression in TSPCs suppressed their clonogenic capacity and reduced their tenogenic potential significantly both in vitro and in vivo. Hence, these findings provide new insights into the identification of subpopulations of TSPCs and illustrate the crucial roles of nestin in TSPC fate decisions and phenotype maintenance, which may assist in future therapeutic strategies to treat tendon disease.- Published
- 2016
- Full Text
- View/download PDF
26. Correlation of Hope and Self-Efficacy With Job Satisfaction, Job Stress, and Organizational Commitment for Correctional Officers in the Taiwan Prison System.
- Author
-
Law FM and Guo GJ
- Subjects
- Adult, Female, Humans, Male, Middle Aged, Prisons, Taiwan, Young Adult, Hope, Job Satisfaction, Self Efficacy
- Abstract
The aim of this study was to explore the correlation of hope and self-efficacy with job satisfaction, job stress, and organizational commitment for correctional officers in the Taiwan prison system while controlling for the shared effects of the nature of the institution (i.e., for male or female inmates) and personal characteristics of the officers (i.e., gender, age, and years of work experience). Hope in the context of this study refers to a cognitive set and motivational state that involves reciprocal interaction between goal-directed energy (agency) and planned pathways to meet the goals (pathway). It is a personality trait of hopefulness, rather than having hope for the prisoners restructuring their future. Self-efficacy refers to the belief that individuals have regarding their ability to perform necessary tasks to achieve goals. Although they share similar constructs, hope theory places emphasis on cross-situational goal-directed thought, whereas the concept of self-efficacy focuses on situation-specific goals. The participants were 133 correctional personnel from two correctional institutions, one with male inmates and the other with female inmates, in central Taiwan. The results of ordinary least squares regression analysis indicated that hope had a significant positive association with job satisfaction and a significant negative association with job stress. Self-efficacy had a significant positive association with job satisfaction and organizational commitment. Finally, job satisfaction had a significant positive association with organizational commitment., (© The Author(s) 2015.)
- Published
- 2016
- Full Text
- View/download PDF
27. Effects of ensembles on methane hydrate nucleation kinetics.
- Author
-
Zhang Z, Liu CJ, Walsh MR, and Guo GJ
- Abstract
By performing molecular dynamics simulations to form a hydrate with a methane nano-bubble in liquid water at 250 K and 50 MPa, we report how different ensembles, such as the NPT, NVT, and NVE ensembles, affect the nucleation kinetics of the methane hydrate. The nucleation trajectories are monitored using the face-saturated incomplete cage analysis (FSICA) and the mutually coordinated guest (MCG) order parameter (OP). The nucleation rate and the critical nucleus are obtained using the mean first-passage time (MFPT) method based on the FS cages and the MCG-1 OPs, respectively. The fitting results of MFPT show that hydrate nucleation and growth are coupled together, consistent with the cage adsorption hypothesis which emphasizes that the cage adsorption of methane is a mechanism for both hydrate nucleation and growth. For the three different ensembles, the hydrate nucleation rate is quantitatively ordered as follows: NPT > NVT > NVE, while the sequence of hydrate crystallinity is exactly reversed. However, the largest size of the critical nucleus appears in the NVT ensemble, rather than in the NVE ensemble. These results are helpful for choosing a suitable ensemble when to study hydrate formation via computer simulations, and emphasize the importance of the order degree of the critical nucleus.
- Published
- 2016
- Full Text
- View/download PDF
28. Genome-Wide Identification and Expression Analysis of WRKY Gene Family in Capsicum annuum L.
- Author
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Diao WP, Snyder JC, Wang SB, Liu JB, Pan BG, Guo GJ, and Wei G
- Abstract
The WRKY family of transcription factors is one of the most important families of plant transcriptional regulators with members regulating multiple biological processes, especially in regulating defense against biotic and abiotic stresses. However, little information is available about WRKYs in pepper (Capsicum annuum L.). The recent release of completely assembled genome sequences of pepper allowed us to perform a genome-wide investigation for pepper WRKY proteins. In the present study, a total of 71 WRKY genes were identified in the pepper genome. According to structural features of their encoded proteins, the pepper WRKY genes (CaWRKY) were classified into three main groups, with the second group further divided into five subgroups. Genome mapping analysis revealed that CaWRKY were enriched on four chromosomes, especially on chromosome 1, and 15.5% of the family members were tandemly duplicated genes. A phylogenetic tree was constructed depending on WRKY domain' sequences derived from pepper and Arabidopsis. The expression of 21 selected CaWRKY genes in response to seven different biotic and abiotic stresses (salt, heat shock, drought, Phytophtora capsici, SA, MeJA, and ABA) was evaluated by quantitative RT-PCR; Some CaWRKYs were highly expressed and up-regulated by stress treatment. Our results will provide a platform for functional identification and molecular breeding studies of WRKY genes in pepper.
- Published
- 2016
- Full Text
- View/download PDF
29. The impact of reality therapy on self-efficacy for substance-involved female offenders in Taiwan.
- Author
-
Law FM and Guo GJ
- Subjects
- Adaptation, Psychological, Adolescent, Adult, Decision Making, Female, Humans, Middle Aged, Social Skills, Substance-Related Disorders psychology, Taiwan, Young Adult, Prisoners legislation & jurisprudence, Prisoners psychology, Reality Therapy legislation & jurisprudence, Reality Therapy methods, Self Efficacy, Substance-Related Disorders rehabilitation
- Abstract
This study aimed to fulfill a twofold purpose. First, a 12-session reality therapy drug treatment program to enhance substance-involved females' self-efficacy in three aspects, which have been demonstrated to be essential to recovery, was designed and implemented. Second, to test the effectiveness of the treatment program, the Index of Sense of Self-Efficacy Scale was developed and validated using Principal Component Analysis and Confirmatory Factor Analysis. The participants in the drug treatment program were 40 incarcerated substance-involved female offenders, who were randomly assigned to equal-sized experimental and control groups. The results of the study, obtained by ANCOVA analysis, showed significant differences in the post-test scores for sense of self-efficacy in decision making, action-planning, and coping and social skills for the members of the two groups., (© The Author(s) 2014.)
- Published
- 2015
- Full Text
- View/download PDF
30. Microcanonical molecular simulations of methane hydrate nucleation and growth: evidence that direct nucleation to sI hydrate is among the multiple nucleation pathways.
- Author
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Zhang Z, Walsh MR, and Guo GJ
- Abstract
The results of six high-precision constant energy molecular dynamics (MD) simulations initiated from methane-water systems equilibrated at 80 MPa and 250 K indicate that methane hydrates can nucleate via multiple pathways. Five trajectories nucleate to an amorphous solid. One trajectory nucleates to a structure-I hydrate template with long-range order which spans the simulation box across periodic boundaries despite the presence of several defects. While experimental and simulation data for hydrate nucleation with different time- and length-scales suggest that there may exist multiple pathways for nucleation, including metastable intermediates and the direct formation of the globally-stable phase, this work provides the most compelling evidence that direct formation to the globally stable crystalline phase is one of the multiple pathways available for hydrate nucleation.
- Published
- 2015
- Full Text
- View/download PDF
31. Who is in charge of your recovery? The effectiveness of reality therapy for female drug offenders in Taiwan.
- Author
-
Law FM and Guo GJ
- Subjects
- Adolescent, Adult, Female, Humans, Internal-External Control, Personal Autonomy, Psychometrics statistics & numerical data, Reproducibility of Results, Self Care psychology, Sex Factors, Substance-Related Disorders diagnosis, Substance-Related Disorders psychology, Surveys and Questionnaires, Taiwan, Young Adult, Prisoners psychology, Reality Therapy, Substance-Related Disorders rehabilitation
- Abstract
This study was designed to fulfill a twofold purpose. First, a 12-session reality therapy drug treatment program to help female drug abusers achieve a better recovery was developed. Second, based on previous research in reality therapy, the Index of Sense of Self-Control in Recovery for Drug Offenders was developed, and the instrument was validated using principal components analysis and confirmatory factor analysis. Later, ANCOVA was used to test the effectiveness of the treatment program. The participants were 48 female drug offenders, who were randomly assigned to equal-sized experimental and control groups. The results of the study showed significant differences in the posttest scores for the sense of self-determination and sense of self-control for the members of the two groups.
- Published
- 2014
- Full Text
- View/download PDF
32. Celecoxib inhibits Helicobacter pylori-induced invasion of gastric cancer cells through an adenine nucleotide translocator-dependent mechanism.
- Author
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Lan C, Yang L, Fan L, Zhang Y, Wang J, Guo GJ, Wan S, Yang S, Wang R, and Fang D
- Subjects
- Anoikis drug effects, Celecoxib, Cell Movement drug effects, Cell Proliferation drug effects, Cells, Cultured, Helicobacter Infections complications, Helicobacter Infections metabolism, Humans, Neoplasm Invasiveness, Protein Isoforms metabolism, Stomach Neoplasms etiology, Stomach Neoplasms metabolism, Cyclooxygenase 2 Inhibitors pharmacology, Helicobacter Infections pathology, Helicobacter pylori physiology, Mitochondrial ADP, ATP Translocases metabolism, Pyrazoles pharmacology, Stomach Neoplasms pathology, Sulfonamides pharmacology
- Abstract
Cyclooxygenase-2 (COX-2) inhibitor, celecoxib, causes growth inhibition of human gastric carcinoma cells, but it remains unclear whether celecoxib inhibits Helicobacter pylori-induced invasion of gastric cancer cells. The adenine nucleotide translocator (ANT) is a mitochondrial bi-functional protein. We speculate that ANT-dependent pathways might contribute to H. pylori-induced invasion and metastasis of gastric cancer cells. Therefore, in the present study, we evaluate the effect of celecoxib on H. pylori-induced gastric cancer cell motility and invasion. We also explore the role of ANTs in H. pylori-induced gastric cancer cell motility and invasion of gastric cancer cell line AGS. Our results demonstrate that celecoxib induces anoikis-like apoptosis and suppresses the proliferation and invasion of gastric cancer cells induced by H. pylori in culture. RT-PCR and Western blot analysis indicates that celecoxib upregulates the expression of ANT1 and ANT3; however, celecoxib did not increase the expression of ANT2. Our results suggest that celecoxib could be an effective means for suppressing proliferation and invasion of gastric cancer cells induced by H. pylori through an adenine nucleotide translocator-dependent mechanism.
- Published
- 2013
- Full Text
- View/download PDF
33. Solubility of aqueous methane under metastable conditions: implications for gas hydrate nucleation.
- Author
-
Guo GJ and Rodger PM
- Abstract
To understand the prenucleation stage of methane hydrate formation, we measured methane solubility under metastable conditions using molecular dynamics simulations. Three factors that influence solubility are considered: temperature, pressure, and the strength of the modeled van der Waals attraction between methane and water. Moreover, the naturally formed water cages and methane clusters in the methane solutions are analyzed. We find that both lowering the temperature and increasing the pressure increase methane solubility, but lowering the temperature is more effective than increasing the pressure in promoting hydrate nucleation because the former induces more water cages to form while the latter makes them less prevalent. With an increase in methane solubility, the chance of forming large methane clusters increases, with the distribution of cluster sizes being exponential. The critical solubility, beyond which the metastable solutions spontaneously form hydrate, is estimated to be ~0.05 mole fraction in this work, corresponding to the concentration of 1.7 methane molecules/nm(3). This value agrees well with the cage adsorption hypothesis of hydrate nucleation.
- Published
- 2013
- Full Text
- View/download PDF
34. Hope and recovery from substance abuse for female drug offenders in Taiwan.
- Author
-
Law FM and Guo GJ
- Subjects
- Adaptation, Psychological, Adult, Cross-Sectional Studies, Emotional Intelligence, Female, Humans, Life Change Events, Middle Aged, Patient Satisfaction, Personality Inventory statistics & numerical data, Prisoners legislation & jurisprudence, Psychological Theory, Psychometrics, Self Concept, Substance-Related Disorders epidemiology, Taiwan, Young Adult, Culture, Drug and Narcotic Control legislation & jurisprudence, Goals, Motivation, Prisoners psychology, Psychotherapy, Group, Substance-Related Disorders psychology, Substance-Related Disorders rehabilitation
- Abstract
This study was designed to fulfill a twofold purpose. First, based on the hope theory framework and previous research, a 16-session hope-based substance abuse treatment program to help female drug abusers achieve a better recovery was developed. Second, ANCOVA was used to test the effectiveness of this treatment model. The participants were 40 female drug offenders who were randomly assigned into experimental and control groups. The 20 experimental group participants received 16 sessions of hope-based substance abuse treatment whereas the 20 control group members were put on the waiting list for another term of treatment. The results indicated that the members of the two groups had significant differences in their posttest scores for recovery goal setting and pursuing, pathway controlling, adequate energy, knowledge of the changing process, ability to cope, adequate cognition, emotion regulation, and self-esteem.
- Published
- 2012
- Full Text
- View/download PDF
35. Efficient doping and energy transfer from ZnO to Eu3+ ions in Eu(3+)-doped ZnO nanocrystals.
- Author
-
Luo L, Huang FY, Guo GJ, Tanner PA, Chen J, Tao YT, Zhou J, Yuan LY, Chen SY, Chueh YL, Fan HH, Li KF, and Cheah KW
- Abstract
Successful doping of Eu3+ ions into ZnO nanocrystals has been realized by using a low temperature wet chemical doping technique. The substitution of Eu3+ for Zn2+ is shown to be dominant in the Eu-doped ZnO nanocrystals by analyzing the X-ray diffraction patterns, transmission electron microscopy images, Raman and selectively excited photoluminescence spectra. Measurement of the luminescence from the samples shows that the excited ZnO transfers the excited energy efficiently to the doped Eu3+ ions, giving rise to efficient emission at red spectral region. The red emission quantum yield is measured to be 31% at room temperature. The temperature dependence of photoluminescence and the photoluminescence excitation spectra have also been investigated, showing strong energy coupling between the ZnO host and Eu3+ ions through free and bound excitons. The result indicates that Eu3+ ion-doped ZnO nanocrystals are promising light-conversion materials and have potential application in highly distinguishable emissive flat panel display and LED backlights.
- Published
- 2012
- Full Text
- View/download PDF
36. Using the face-saturated incomplete cage analysis to quantify the cage compositions and cage linking structures of amorphous phase hydrates.
- Author
-
Guo GJ, Zhang YG, Liu CJ, and Li KH
- Abstract
Recent advances in the molecular dynamics simulations of spontaneous nucleation and growth of methane hydrate show that an amorphous phase of the hydrate is first reached. However, the amorphous hydrate has not been well described, due to the insufficient identification of cage structures. Here, we develop a method, called "face-saturated incomplete cage analysis", which can identify all face-saturated cages in a given system. As a result, it is found that thousands of cage types and abundant occupancy states are present in the amorphous hydrate. Moreover, the crystallinity of amorphous hydrate is evaluated according to the quantitative calculation of cage linking structures, and the critical nucleus of hydrate is also estimated on the basis of clustering analysis for all face-saturated cages., (This journal is © the Owner Societies 2011)
- Published
- 2011
- Full Text
- View/download PDF
37. Why can water cages adsorb aqueous methane? A potential of mean force calculation on hydrate nucleation mechanisms.
- Author
-
Guo GJ, Li M, Zhang YG, and Wu CH
- Abstract
By performing constrained molecular dynamics simulations in the methane-water system, we successfully calculated the potential of mean force (PMF) between a dodecahedral water cage (DWC) and dissolved methane for the first time. As a function of the distance between DWC and methane, this is characterized by a deep well at approximately 6.2 A and a shallow well at approximately 10.2 A, separated by a potential barrier at approximately 8.8 A. We investigated how the guest molecule, cage rigidity and the cage orientation affected the PMF. The most important finding is that the DWC itself strongly adsorbs methane and the adsorption interaction is independent of the guests. Moreover, the activation energy of the DWC adsorbing methane is comparable to that of hydrogen bonds, despite differing by a factor of approximately 10% when considering different water-methane interaction potentials. We explain that the cage-methane adsorption interaction is a special case of the hydrophobic interaction between methane molecules. The strong net attraction in the DWC shell with radii between 6.2 and 8.8 A may act as the inherent driving force that controls hydrate formation. A cage adsorption hypothesis for hydrate nucleation is thus proposed and discussed.
- Published
- 2009
- Full Text
- View/download PDF
38. Can the dodecahedral water cluster naturally form in methane aqueous solutions? A molecular dynamics study on the hydrate nucleation mechanisms.
- Author
-
Guo GJ, Zhang YG, Li M, and Wu CH
- Abstract
By performing a large scale of molecular dynamics simulations, we analyze 60 x 10(6) hydration shells of methane to examine whether the dodecahedral water cluster (DWC) can naturally form in methane aqueous solutions--a fundamental question relevant to the nucleation mechanisms of methane hydrate. The analyzing method is based on identifying the incomplete cages (ICs) from the hydration shells and quantifying their cagelike degrees (zetaC=0-1). Here, the zetaC is calculated according to the H-bond topological network of IC and reflects how the IC resembles the complete polyhedral cage. In this study, we obtain the zetaC distributions of ICs in methane solutions and find the occurrence probabilities of ICs reduce with zetaC very rapidly. The ICs with zetaC>or=0.65 are studied, which can be regarded as the acceptable cagelike structures in appearance. Both increasing the methane concentration and lowering the temperature can increase their occurrence probabilities through slowing down the water molecules. Their shapes, cage-maker numbers, and average radii are also discussed. About 13-14 of these ICs are face saturated, meaning that every edges are shared by two faces. The face-saturated ICs have the potential to act as precursors of hydrate nucleus because they can prevent the encaged methane from directly contacting other dissolved methane when an event of methane aggregation occurs. The complete cages, i.e., the ICs with zetaC=1, form only in the solutions with high methane concentration, and their occurrence probabilities are about 10(-6). Most of their shapes are different from the known hydrate cages, but we indeed observe a standard 5(12)6(2) hydrate cage. We do not find the expected DWC, and its occurrence probability is estimated to be far less than 10(-7). Additionally, the IC analysis proposed in this work is also very useful in other studies not only on the formation, dissociation, and structural transition of hydrates but also on the hydrophobic hydration of apolar solutes.
- Published
- 2008
- Full Text
- View/download PDF
39. [Gadolinium-loaded nanoparticle as a novel molecular imaging contrast agent for magnetic resonance imaging].
- Author
-
Liu LZ, Guo GJ, Zeng MS, Lü YC, Liu XW, Cui CY, Wu PH, and Li L
- Subjects
- Animals, Cell Line, Tumor, Contrast Media chemistry, Female, Gadolinium DTPA chemistry, Humans, Mice, Mice, Inbred BALB C, Mice, Nude, Microscopy, Electron, Transmission, Nanostructures chemistry, Nanostructures ultrastructure, Nasopharyngeal Neoplasms metabolism, Nasopharyngeal Neoplasms pathology, Neoplasm Transplantation, Neoplasms, Experimental metabolism, Neoplasms, Experimental pathology, Particle Size, Transplantation, Heterologous, Contrast Media pharmacokinetics, Gadolinium DTPA pharmacokinetics, Magnetic Resonance Spectroscopy methods
- Abstract
Objective: To synthesize a novel gadolinium-loaded nanoparticle as a molecular imaging contrast agent for magnetic resonance imaging., Methods: Gadolinium ion was incorporated within a silica nanoparticle. The size of this nanosized particle was determined by using transmission electron microscope. The spin-echo (SE) images of nine nanoparticle dilutions in vitro were obtained from a 1.5 T clinical scanner, compared with gadolinium diethylene triaminepenta acetate (Gd-DTPA). In vivo distribution of nanoparticle in Balb/c nude mice and Balb/c nude mice with nasopharyngeal carcinoma (NPC) xenografted CNE-2 tumors was studied at MR imaging, 30 sec, 5 min, 30 min, 1 h, 2 h, 4 h, and 24 h after intravenous administration., Results: The gadolinium-loaded nanoparticle was short rod-shaped, and approximately 30 to 40 nm in diameter. The value of longitudinal relaxativity (r(1)) of gadolinium nanoparticle was much higher than that of Gd-DTPA. Thirty minutes after injection the gadolinium nanoparticle, the signal intensities of liver, kidney and xenografted tumor increased from 226 +/- 10, 283 +/- 7 and 195 +/- 5 to 352 +/- 12, 328 +/- 10 and 245 +/- 7, respectively. The dynamic MRI scanning showed that gadolinium nanoparticles were mainly distributed in liver after intravenous administration. Strong enhancement was also detected in CNE-2 xenografted tumors., Conclusion: A new gadolinium-loaded nanoparticle with high relaxativity was synthesized successfully, and might serve as a carrier for magnetic resonance molecular imaging.
- Published
- 2007
40. [Effect of ileocecum interposition graft as pylorus replacement on glycometabolism].
- Author
-
Zhang JJ, Guo GJ, Jiang DJ, Jiang J, Lei Y, Zhang TF, and Zuo YF
- Subjects
- Animals, Female, Gastric Emptying, Glucose Tolerance Test, Male, Swine, Swine, Miniature, Blood Glucose metabolism, Ileocecal Valve transplantation, Pylorus surgery
- Abstract
Objective: To evaluate the application of ileocecum interposition (ii) graft as pylorus replacement in alimentary reconstruction., Methods: Twenty- one minipigs were randomly divided into three groups: sham operation group (control group), B - i group and ii group. The levels of blood glucose were measured by quick blood glucose testing of paper at 0, 30, 60, 90, and 120 minutes of oral glucose after 60 and 120 post- operative days to compare gastric emptying of liquid feeds., Results: Two months after operation,the peak of blood glucose was (7.8+/- 1.0)mmol/ L, (7.1+/- 0.8)mmol/ L, (4.1+/- 0.4)mmol/ L in B - i, ii group and control group respectively, there were significant differences between the two operation groups and control group (P< 0.01). Four months after operation, the peak of blood glucose was (6.9+/- 1.0) mmol/ L, (5.2+/- 0.8)mmol/ L, (4.2+/- 0.5)mmol/ L, respectively, there was no significant difference between ii group and control group (P > 0.05),but there were significant differences between both of the above two groups and B - i group (P< 0.01)., Conclusion: The ileocecum interposition graft can offer specific advantages over current reconstruction procedures.
- Published
- 2005
41. Lifetimes of cagelike water clusters immersed in bulk liquid water: a molecular dynamics study on gas hydrate nucleation mechanisms.
- Author
-
Guo GJ, Zhang YG, Zhao YJ, Refson K, and Shan GH
- Abstract
Molecular dynamics simulations were performed to observe the evolution of cagelike water clusters immersed in bulk liquid water at 250 and 230 K. Totally, we considered four types of clusters--dodecahedral (5(12)) and tetrakaidecahedral (5(12)6(2)) cagelike water clusters filled with or without a methane molecule, respectively. The lifetimes of these clusters were calculated according to their Lindemann index (delta) using the criterion of delta> or =0.07. The lifetimes of the clusters at 230 K are longer than that at 250 K, and their ratios are the same as the ratio of structure relaxation times of bulk water at these temperatures. For both the filled and empty clusters, the lifetimes of 5(12)6(2) cagelike clusters are similar to that of 5(12) cagelike clusters. Although the methane molecules indeed make the filled cagelike water clusters live longer than the empty ones, the empty cagelike water clusters still have the chance of being long lived. These observations support the cluster nucleation hypothesis for the formation mechanisms of gas hydrates., ((c) 2004 American Institute of Physics)
- Published
- 2004
- Full Text
- View/download PDF
42. Comment on "Computation of the viscosity of a liquid from time averages of stress fluctuations".
- Author
-
Guo GJ, Zhang YG, and Zhao YJ
- Abstract
In a recent paper, Hess and Evans [Phys. Rev. E 64, 011207 (2001)] propose a method different from the conventional Green-Kubo and Einstein methods to calculate viscosity in equilibrium molecular dynamics simulations. For a comparison, we calculate the shear viscosity of SPC/E water at 303 K using these three different methods. We find that the Hess-Evans method is not as good as the other two in practical application, especially for the fluids with high viscosity and complicated relaxation.
- Published
- 2003
- Full Text
- View/download PDF
43. [Phagocytosis of splenic autotransplantation: an experimental study].
- Author
-
Chen WP, Ning KR, and Guo GJ
- Subjects
- Animals, Dogs, Female, Male, Omentum surgery, Rats, Regeneration, Spleen physiology, Splenectomy, Transplantation, Autologous methods, Phagocytosis, Spleen transplantation
- Published
- 1985
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