Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 29
Filter
1.
BMJ Open ; 12(6): e054891, 2022 06 27.
Article in English | MEDLINE | ID: mdl-35760549

ABSTRACT

OBJECTIVES: To clarify non-alcoholic fatty liver disease (NAFLD) prevalence, risk factors and clinical outcome in an exemplary Chinese population, a cohort of company employees was followed up for 11 years. DESIGN: Retrospective cohort study. SETTING: Between 2006 and 2016 in Ning bo, China. PARTICIPANTS: 13 032 company employees. RESULTS: Over 11 years, the prevalence of NAFLD increased from 17.2% to 32.4% (men 20.5%-37% vs women 9.8%-22.2%). Male peak prevalence was between 40 and 60 years of age, whereas highest prevalence in women was at an age of 60 years and older. Logistic and Cox regression revealed 16 risk factors, including body mass index (BMI), albumin, white blood cell, triglycerides (TG), high-density lipoprotein, glutamyl transpeptidase, alanine transaminase, creatinine, urea acid, glucose, systolic blood pressure, diastolic blood pressure, blood sedimentation, haemoglobin, platelet and apolipoprotein B2 (p<0.05 for all factors). The area under the curve of these variables for NAFLD is 0.88. However, cause-effect analyses showed that only BMI, gender and TG directly contributed to NAFLD development. Over an 11-year follow-up period, 12.6%, 37.7% and 14.2% of male patients with NAFLD and 11.6%, 44.7% and 22.6% of female patients with NAFLD developed diabetes, hypertension and hyperuricaemia, respectively. Except one male patient who developed cirrhosis, no patients with NAFLD progressed into severe liver disease. CONCLUSION: Diabetes, hypertension and hyperuricaemia are the main clinical outcomes of NAFLD. Eleven years of NAFLD are not sufficient to cause severe liver disease. Age and obesity are direct risk factors for NAFLD. BMI, gender and TG are three parameters directly reflecting the occurrence of NAFLD.


Subject(s)
Diabetes Mellitus , Hypertension , Hyperuricemia , Non-alcoholic Fatty Liver Disease , Female , Follow-Up Studies , Humans , Hypertension/epidemiology , Male , Middle Aged , Non-alcoholic Fatty Liver Disease/epidemiology , Retrospective Studies , Triglycerides
2.
Sci Total Environ ; 776: 145908, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-33647651

ABSTRACT

Assessing perceptions of green spaces is of considerable interest to developers aiming for sustainable urbanization. However, there are numerous challenges facing the development of a rapid, effective, and fine-grained method to assess large-scale greenspace perception. Survey-based studies of perception yielded detailed assessments of green spaces but lacked regional comparisons. The few big-data-based studies of greenspace perception lacked fine-grained explorations. Therefore, we used content analysis to interpret perception in two ways: perceived frequency and perceived satisfaction, including overall park satisfaction and satisfaction with individual landscape features. We analyzed social media posts about urban parks in Beijing, China. A structured lexicon was developed to capture detailed landscape features, and machine learning was employed to assess satisfaction levels. Both of these techniques performed well in interpreting greenspace satisfaction from volunteered textual comments. A detailed study of 50 parks demonstrated that overall park satisfaction was positive. Additionally, individual landscape features were more influential than frequency of landscape features in affecting satisfaction. Our framework confirmed the potential of online comments as complementary to traditional surveys in assessing greenspace perception, while enhancing our understanding of this perception on a regional scale. Practically, this study can facilitate sustainable policy-making regarding urban green spaces, specifically through offering a structured landscape-feature lexicon, rapid regional comparison of various parks, and an emphasis on quality rather than quantity of landscape features.

3.
Am J Gastroenterol ; 115(6): 876-884, 2020 06.
Article in English | MEDLINE | ID: mdl-32282335

ABSTRACT

OBJECTIVE: This study explored the association between light-to-moderate alcohol consumption (LMAC) and risk of type 2 diabetes mellitus (T2DM) in individuals with nonalcoholic fatty liver disease (NAFLD). METHODS: A 9-year cohort study was performed among Chinese men who underwent their annual health checkups between 2009 and 2018. NAFLD was diagnosed based on abdominal ultrasound with exclusion of excess alcohol intake and other causes of liver disease. Logistic regression and Cox proportional regression analyses were applied to identify the risk of prevalent and incident T2DM. RESULTS: Of the 7,079 participants enrolled, 243 had T2DM at baseline and 630 developed T2DM during the 45,456 person-years follow-up. Both at the baseline and by the end of the follow-up, LMAC was associated with a decreased risk of prevalent T2DM in NAFLD-free participants but with a significantly increased risk in patients with NAFLD. LMAC was also associated with a decreased risk of incident T2DM in NAFLD-free participants. The adjusted hazard ratios (95% confidence interval) of incident T2DM were 0.224 (0.115-0.437) and 0.464 (0.303-0.710) for NAFLD-free light drinkers and NAFLD-free moderate drinkers, respectively. Nondrinking, light-drinking, and moderate-drinking patients with NAFLD all showed significantly increased risks of incident T2DM. Compared with NAFLD-free nondrinkers, the adjusted hazard ratios (95% confidence interval) of incident T2DM were 1.672 (1.336-2.092), 2.642 (1.958-3.565), and 2.687 (2.106-3.427) for nondrinking, light-drinking, and moderate-drinking patients with NAFLD, respectively. DISCUSSION: LMAC decreased the risks of prevalent and incident T2DM in NAFLD-free participants. LMAC, however, was associated with an increased risk of T2DM in patients with NAFLD (ClinicalTrials.gov number: NCT03847116).


Subject(s)
Alcohol Drinking/epidemiology , Diabetes Mellitus, Type 2/epidemiology , Non-alcoholic Fatty Liver Disease/epidemiology , Adult , China/epidemiology , Cohort Studies , Glucose Intolerance/epidemiology , Humans , Incidence , Logistic Models , Male , Middle Aged , Prevalence , Proportional Hazards Models , Risk Factors
4.
Biosci Rep ; 40(1)2020 01 31.
Article in English | MEDLINE | ID: mdl-31940026

ABSTRACT

Previous clinical studies highlighted nonalcoholic fatty liver disease (NAFLD) as a hepatic facet of metabolic syndrome, which progresses toward Type 2 diabetes along with an elevation of HbA1c in the blood. Longitudinal observations were performed in a cohort of 2811 participants with no liver disease at inception. The rate of the conversion into NAFLD was 15.7% (440/2811), with a steady increase in prevalence observed in sub-cohorts with increasing HbA1c levels. Moreover, regression analysis indicated that HbA1c levels serve as the risk factors for NAFLD after multiple adjustments (odds ratio: 1.58, P-value < 0.004). When HbA1c-related molecular networks were investigated using natural language programming algorithms, multiple genetic/small molecular (SM) pathways were highlighted as connectors between the HbA1c levels and the development of NAFLD, including ones for nitric oxide, hypoxia and receptor for advanced glycation end products (RAGE). Our results suggest that increased levels of HbA1c may contribute to the progression of NAFLD either directly, by stimulating RAGE or indirectly, through the promotion of hypoxia and suppression of the release of NO. Further studies are needed to test the impact of HbA1c on the development of the chronic liver disease.


Subject(s)
Diabetes Mellitus, Type 2/blood , Glycated Hemoglobin/metabolism , Non-alcoholic Fatty Liver Disease/blood , Aged , Aged, 80 and over , Biomarkers/blood , China/epidemiology , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/genetics , Female , Gene Regulatory Networks , Humans , Incidence , Longitudinal Studies , Male , Middle Aged , Nitric Oxide/metabolism , Non-alcoholic Fatty Liver Disease/diagnosis , Non-alcoholic Fatty Liver Disease/epidemiology , Non-alcoholic Fatty Liver Disease/genetics , Prevalence , Protein Interaction Maps , Receptor for Advanced Glycation End Products/metabolism , Risk Assessment , Risk Factors , Time Factors , Up-Regulation
5.
Clin Exp Hypertens ; 42(1): 61-66, 2020.
Article in English | MEDLINE | ID: mdl-30689431

ABSTRACT

An increased platelet distribution width (PDW) value has been found in various cardiovascular diseases. The objective of this study was to evaluate the association between the PDW and hypertension with hyperhomocysteinemia in an elderly cohort. We performed a cross-sectional analysis among 2,685 elderly individuals who underwent hematological testing and blood pressure assessment. Individuals were divided according to the PDW quartiles. An unconditional multiple logistic regression analysis was used to determine the association between PDW and hypertension with hyperhomocysteinemia, after adjustments for gender, age, drinking status, creatinine levels, glucose levels, uric acid levels, triglyceride levels, platelet counts and body mass index. Homocysteine was observed to steadily and remarkably increase in the PDW quartiles. The PDW values of the hypertension with hyperhomocysteinemia group were significantly greater than the PDW values in the hypertension without hyperhomocysteinemia group or the normotension group. The PDW levels were associated with hypertension and hyperhomocysteinemia independently of the previously mentioned risk factors, and the odds ratio of the hypertension with hyperhomocysteinemia group was steadily and remarkably increased, by as much as two-fold, in the fourth quartile vs. the first quartile. In this elderly population-based cohort, elevated PDW levels were independently associated with hypertension and hyperhomocysteinemia, which may indicate that hypertension and hyperhomocysteinemia can induce platelet activation.


Subject(s)
Blood Platelets , Hyperhomocysteinemia/blood , Hypertension/blood , Aged , Aged, 80 and over , Blood Pressure , Body Mass Index , Cohort Studies , Cross-Sectional Studies , Female , Humans , Hyperhomocysteinemia/complications , Hypertension/complications , Male , Mean Platelet Volume , Middle Aged , Platelet Activation
6.
Technol Cancer Res Treat ; 18: 1533033819883633, 2019.
Article in English | MEDLINE | ID: mdl-31684829

ABSTRACT

OBJECTIVE: To investigate the effect of long noncoding RNA GM16343 on interleukin 36ß promotion of CD8+T cells in tumor microenvironment regulation. METHODS: The differentially expressed long noncoding RNA in interleukin 36ß-stimulated mouse CD8+T cells was screened by gene chip technology, and the significant differentially expressed long noncoding RNAs were verified by real-time polymerase chain reaction. The lentiviral vector that overexpresses or knockdown GM16343 was constructed, transfected into CD8+T cells, and stimulated with interleukin 36ß, and the amount of interferon γ secreted was detected by enzyme-linked immunosorbent assay. A mouse subcutaneous xenograft model that stably express interleukin 36ß was established, and the tumor size and mouse survival time were observed by stimulation with CD8+T cells overexpression or knockdown of GM16343. RESULTS: A total of 12 long noncoding RNAs with significant differences were screened by gene chip analysis. Real-time polymerase chain reaction showed that the difference in GM16343 was larger, and the difference between the groups was observed to be the most significant. Compared to control group, CD8+T cells overexpressing GM16343 increased the secretion of interferon γ, and the tumor diameter of the mice after stimulation showed significant reduction, and the survival time showed significant prolongation. Compared to control group, the CD8+T cells after GM16343 were knocked down. The interferon γ secretion was decreased, and no significant change in tumor diameter and survival time was observed. CONCLUSION: Interleukin 36ß may enhance antitumor immune response of CD8+T cells by regulating GM16343.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Interleukin-1/metabolism , Neoplasms/etiology , Neoplasms/metabolism , RNA, Long Noncoding/genetics , Tumor Microenvironment/genetics , Tumor Microenvironment/immunology , Animals , Cell Proliferation , Cells, Cultured , Computational Biology/methods , Disease Models, Animal , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Gene Knockout Techniques , Mice , Neoplasms/mortality , Neoplasms/pathology , RNA Interference , RNA, Small Interfering/genetics , Tumor Burden
7.
ACS Appl Mater Interfaces ; 11(42): 38929-38936, 2019 Oct 23.
Article in English | MEDLINE | ID: mdl-31576734

ABSTRACT

The recent demand for analogue devices for neuromorphic applications requires modulation of multiple nonvolatile states. Ferroelectricity with multiple polarization states enables neuromorphic applications with various architectures. However, deterministic control of ferroelectric polarization states with conventional ferroelectric materials has been met with accessibility issues. Here, we report unprecedented stable accessibility with robust stability of multiple polarization states in ferroelectric HfO2. Through the combination of conventional voltage measurements, hysteresis temperature dependence analysis, piezoelectric force microscopy, first-principles calculations, and Monte Carlo simulations, we suggest that the unprecedented stability of intermediate states in ferroelectric HfO2 is due to the small critical volume size for nucleation and the large activation energy for ferroelectric dipole flipping. This work demonstrates the potential of ferroelectric HfO2 for analogue device applications enabling neuromorphic computing.

8.
J Org Chem ; 84(11): 7238-7243, 2019 Jun 07.
Article in English | MEDLINE | ID: mdl-31083942

ABSTRACT

Experiments show that 1,1'-bi-2-naphthol (BINOL) undergoes facile C1-C1' bond cleavage under action of triflic acid at temperatures above 0 °C to give mainly 2-naphthol along with oligomeric material. CASSCF and MRMP//CASSCF computations have demonstrated unambiguously that this unusual mode of scission of the biaryl bond can occur in the C1,C1'-diprotonated form of BINOL via a mechanism involving homolytic cleavage prompted by the intramolecular electrostatic repulsion. These findings also provide insights into the mechanism of a comparatively easy thermal cleavage of BINOL, implying the intermediacy of its neutral diketo form.

9.
Oncol Lett ; 17(5): 4401-4408, 2019 May.
Article in English | MEDLINE | ID: mdl-30944633

ABSTRACT

Radiotherapy is one of the main adjuvant treatments for gastric cancer (GC) that can effectively reduce local recurrence and improve survival rates. However, radiotherapy may result in cytotoxicity and not benefit all patients. This highlights the requirement for identifying potential radiosensitivity genes in GC. The current study investigated the association between tripartite motif containing 36 (TRIM36) status and the prognosis of patients with GC receiving radiotherapy. A total of 371 patients with GC were selected from The Cancer Genome Atlas and randomly divided into test and the validation groups. The results revealed that TRIM36 expression was not associated with the overall survival (OS) rate. Patients who received radiotherapy with high TRIM36 expression had an improved OS rate compared with patients who did not receive radiotherapy in the test group, as demonstrated by univariate analysis [hazard ratio (HR), 0.062; 95% confidence interval (CI), 0.008-0.462; P=0.007] and multivariate analysis (HR, 0.095; 95% CI, 0.012-0.748; P=0.025). In the validation group, patients with high TRIM36 expression had decreased mortality risk when they received radiotherapy compared with patients who did not receive radiotherapy, as determined by univariate analysis (HR, 0.190; 95% CI, 0.067-0.540; P=0.002) and multivariate analysis (HR, 0.075; 95% CI, 0.020-0.276; P<0.001). However, for patients with low expression, no significant difference was identified in the overall survival rates between the radiotherapy and non-radiotherapy groups. Chi-squared analysis revealed that the expression status of TRIM36 was an independent factor and was not associated with clinicopathological factors. The results indicated that patients with high TRIM36 expression receiving radiotherapy exhibited an improved OS rate. TRIM36 may therefore be an important factor affecting the clinical prognosis of patients with GC receiving radiotherapy and may be considered as a potential radiosensitivity gene signature.

10.
Org Biomol Chem ; 17(16): 3971-3977, 2019 Apr 17.
Article in English | MEDLINE | ID: mdl-30942805

ABSTRACT

7,7'-Dihydroxy-1,1'-bi-2-naphthol, as a result of superelectrophilic activation in the presence of an excess of aluminum halides, reacts with cyclohexane and benzene to yield 5,6,7,8,5',6',7',8'-octahydro-7,7'-dioxo-bi-2-naphthol and its 5,5'-diphenyl derivative, respectively. In contrast, isomeric 6,6'-dihydroxy-1,1'-bi-2-naphthol does not react at all under the same reaction conditions, while the parent 1,1'-bi-2-naphthol (BINOL) reveals an alternative mode of behavior. The mechanistic aspects of these intriguing results are discussed on the basis of experimental and theoretical (DFT) study of the protonation and complexation properties of the starting BINOLs.

11.
BMC Gastroenterol ; 19(1): 14, 2019 Jan 21.
Article in English | MEDLINE | ID: mdl-30665367

ABSTRACT

BACKGROUND: Gastric Helicobacter pylori (H. pylori) is linked with chronic gastritis, peptic ulcer disease, and gastric malignancy. This study aims to investigate the association of gastric H. pylori with colorectal adenomatous polyps (CAP) in the Chinese population. METHODS: One thousand three hundred seventy five workers of China Petroleum and Chemical Corporation Sinopec Zhenhai Refining & Chemical Branch were recruited. Carbon-13 urea breathes test, and colorectal biopsies were utilized to detect H. pylori and CAP. The correlation between the number and distribution of CAP with H. pylori infection (HPI) was determined. Logistic regression models were applied to calculate the effect of H. pylori on the risk of CAP and pathway studio was used to attribute the cellular processes linking HPI and adenomatous polyps. RESULTS: One hundred Eighty participants were diagnosed as CAP, and 1195 participants were classified as healthy control. The prevalence of HPI in the CAP group was significantly higher than that in the healthy control group (57.8% verse 40.1%) (p<0.001). It was the number not the distribution of CAP corrected with H. pylori status. An increased risk of CAP was found to be associated with H. pylori (OR = 3.237; 95.0% CI 2.184-4.798, p = 0.00) even after multiple parameters adjustment. Pathway studio analysis demonstrated that HPI connected with CAP at multi-level. CONCLUSIONS: HPI is associated with an increased risk of CAP in the Chinese population.


Subject(s)
Adenomatous Polyps/epidemiology , Colorectal Neoplasms/epidemiology , Gastrointestinal Diseases/epidemiology , Helicobacter Infections/epidemiology , Helicobacter pylori , Adenomatous Polyps/pathology , Adult , Aged , China/epidemiology , Colorectal Neoplasms/pathology , Comorbidity , Female , Gastrointestinal Diseases/microbiology , Humans , Logistic Models , Male , Middle Aged , Prevalence , Risk Factors
12.
ACS Appl Mater Interfaces ; 11(3): 3142-3149, 2019 Jan 23.
Article in English | MEDLINE | ID: mdl-30592198

ABSTRACT

The ferroelectricity in ultrathin HfO2 offers a viable alternative to ferroelectric memory. A reliable switching behavior is required for commercial applications; however, many intriguing features of this material have not been resolved. Herein, we report an increase in the remnant polarization after electric field cycling, known as the "wake-up" effect, in terms of the change in the polarization-switching dynamics of a Si-doped HfO2 thin film. Compared with a pristine specimen, the Si-doped HfO2 thin film exhibited a partial increase in polarization after a finite number of ferroelectric switching behaviors. The polarization-switching behavior was analyzed using the nucleation-limited switching model characterized by a Lorentzian distribution of logarithmic domain-switching times. The polarization switching was simulated using the Monte Carlo method with respect to the effect of defects. Comparing the experimental results with the simulations revealed that the wake-up effect in the HfO2 thin film is accompanied by the suppression of disorder.

13.
Org Biomol Chem ; 16(47): 9129-9132, 2018 12 05.
Article in English | MEDLINE | ID: mdl-30460957

ABSTRACT

1-Nitronaphthalene smoothly reacts with benzene and undergoes selective reduction with cyclohexane in the presence of aluminum chloride to give 2,4,4-triphenyl-3,4-dihydronaphthalen-1(2H)-one oxime and 5,6,7,8-tetrahydro-1-naphthylamine, respectively. The mechanistic aspects of these and related reactions are discussed on the basis of DFT, providing insight into the protonation behavior of 1-nitronaphthalene coordinated to AlCl3.

14.
Biomed Res Int ; 2018: 5628749, 2018.
Article in English | MEDLINE | ID: mdl-30112401

ABSTRACT

BACKGROUND: Atrial fibrillation and nonalcoholic fatty liver disease are two pathological conditions that are highly prevalent worldwide and share multiple CVD risk factors. There are rare researches performed among elderly adults. AIMS: We conducted this cross-sectional analysis of elderly adults (≥65 years) to investigate the association between atrial fibrillation and nonalcoholic fatty liver disease. METHODS: We analyzed clinical data of the elderly adults (≥ 65 years) who had health examination in Zhenhai Lianhua Hospital, Ningbo, China, in 2014. RESULTS: 522 of the 1688 participants were diagnosed with nonalcoholic fatty liver disease, and 39 participants were diagnosed as having atrial fibrillation. Nonalcoholic fatty liver disease was associated with risk factors for AF in the elderly Chinese population (OR 1.95, 95% CI 1.03-3.69). Adjustments for age, gender, systolic blood pressure, fasting plasma glucose, γ-glutamyl transpeptidase, high-density lipoprotein, triglycerides, total cholesterol and albumin, nonalcoholic fatty liver disease, and prevalent atrial fibrillation remained statistically significant (OR 2.76, 95% CI 1.32-5.77). CONCLUSIONS: Our results show that nonalcoholic fatty liver disease is associated with an increased risk of atrial fibrillation in an elderly Chinese population.


Subject(s)
Atrial Fibrillation/complications , Non-alcoholic Fatty Liver Disease/complications , Adult , Aged , Atrial Fibrillation/epidemiology , China/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Risk Factors , Uric Acid
15.
Appl Physiol Nutr Metab ; 42(3): 295-301, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28177748

ABSTRACT

Possible association between Helicobacter pylori infection (HPI) and nonalcoholic fatty liver disease (NAFLD) has been proposed by several studies with inconsistent conclusions. Here, we studied the association between HPI and NAFLD at 3 levels: (i) genetic level; (ii) small molecular level; and (iii) clinical level. Relation data between diseases, genes, and small molecules were acquired from Pathway Studio ResNet Mammalian database. Clinical data were acquired from 2263 elderly South Chinese subjects, including 603 NAFLD patients and 1660 subjects without NAFLD. Results showed that HPI and NAFLD present significantly shared genetic bases (95 genes, p value = 2.5E-72), demonstrating multiple common genetic pathways (enrichment p value ≤ 4.38E-20 for the top 10 pathways). Genetic network analysis suggested that mutual regulation may exist between HPI and NAFLD through 21 out of 95 genes. Furthermore, 85 out of the 95 genes manifested strong interaction with 12 small molecules/drugs that demonstrate effectiveness in treating both diseases. Clinical results showed that HPI rate in the NAFLD group was significantly higher than that in the group without NAFLD (51.9% vs. 43.6%; p value = 4.9E-4). Multivariate logistic regression results supported the observations and suggested that HPI served as a risk factor for NAFLD in the experiment data studied (odds ratio: 1.387, p value = 0.018). Results from this study support the hypothesis that complex biological association may exist between HPI and NAFLD, which partially explains the significant clinical co-incidence in the elderly population of south China.


Subject(s)
Helicobacter Infections/genetics , Non-alcoholic Fatty Liver Disease/genetics , Aged , Asian People , Case-Control Studies , China , Female , Gene Expression Regulation , Gene Regulatory Networks , Gene-Environment Interaction , Helicobacter Infections/complications , Helicobacter Infections/diagnosis , Helicobacter pylori/isolation & purification , Humans , Logistic Models , Male , Middle Aged , Multivariate Analysis , Non-alcoholic Fatty Liver Disease/complications , Non-alcoholic Fatty Liver Disease/diagnosis , Risk Factors
16.
Org Lett ; 19(3): 532-535, 2017 02 03.
Article in English | MEDLINE | ID: mdl-28094529

ABSTRACT

The behavior of 1,1'-bi-2-naphthol (BINOL) in variety of (super)acid media has been studied by NMR. The results are combined with the theoretical (DFT) study of the role of mono- and diprotonated forms of BINOL in the acid-catalyzed atropisomerization of this compound. It is demonstrated that the process of enantiomeric configuration exchange proceeds mainly via internal rotation around the C1(sp3)-C1'(sp3) bond in intermediates such as C1-monoprotonated keto or C1,C1'-diprotonated forms of BINOL, depending on the acidity level.

17.
Science ; 343(6177): 1339-43, 2014 Mar 21.
Article in English | MEDLINE | ID: mdl-24578531

ABSTRACT

Control of structure at the atomic level can precisely and effectively tune catalytic properties of materials, enabling enhancement in both activity and durability. We synthesized a highly active and durable class of electrocatalysts by exploiting the structural evolution of platinum-nickel (Pt-Ni) bimetallic nanocrystals. The starting material, crystalline PtNi3 polyhedra, transforms in solution by interior erosion into Pt3Ni nanoframes with surfaces that offer three-dimensional molecular accessibility. The edges of the Pt-rich PtNi3 polyhedra are maintained in the final Pt3Ni nanoframes. Both the interior and exterior catalytic surfaces of this open-framework structure are composed of the nanosegregated Pt-skin structure, which exhibits enhanced oxygen reduction reaction (ORR) activity. The Pt3Ni nanoframe catalysts achieved a factor of 36 enhancement in mass activity and a factor of 22 enhancement in specific activity, respectively, for this reaction (relative to state-of-the-art platinum-carbon catalysts) during prolonged exposure to reaction conditions.

18.
J Phys Chem Lett ; 5(15): 2626-31, 2014 Aug 07.
Article in English | MEDLINE | ID: mdl-26277954

ABSTRACT

We demonstrate the critical role of the specific atomic arrangement at step sites in the restructuring processes of low-coordinated surface atoms at high adsorbate coverage. By using high-pressure scanning tunneling microscopy (HP-STM) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), we have investigated the reconstruction of Pt(332) (with (111)-oriented triangular steps) and Pt(557) surfaces (with (100)-oriented square steps) in the mixture of CO and C2H4 in the Torr pressure range at room temperature. CO creates Pt clusters at the step edges on both surfaces, although the clusters have different shapes and densities. A subsequent exposure to a similar partial pressure of C2H4 partially reverts the clusters on Pt(332). In contrast, the cluster structure is barely changed on Pt(557). These different reconstruction phenomena are attributed to the fact that the 3-fold (111)-step sites on Pt(332) allows for adsorption of ethylidyne-a strong adsorbate formed from ethylene-that does not form on the 4-fold (100)-step sites on Pt(557).

19.
J Am Chem Soc ; 135(34): 12560-3, 2013 Aug 28.
Article in English | MEDLINE | ID: mdl-23952637

ABSTRACT

The surface structure of Pt(557) during the catalytic oxidation of hydrogen was studied with in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. At 298 K, the surface Pt oxide formed after exposing Pt(557) to approximately 1 Torr of O2 can be readily removed by H2, at H2 partial pressures below 50 mTorr. Water is detected as the product in the gas phase, which also coadsorbs with hydroxyl groups on the Pt(557) surface.

20.
World J Gastroenterol ; 19(27): 4393-9, 2013 Jul 21.
Article in English | MEDLINE | ID: mdl-23885152

ABSTRACT

AIM: To investigate the prevalence and risk factors of polypoid lesions of the gallbladder (PLGs) in petrochemical employees in Ningbo, Zhejiang Province, China. METHODS: All active and retired employees aged 20-90 years (n = 11098) of a refinery and chemical plant in eastern China were requested to participate in a health survey. The participants were subjected to interview, physical examination, laboratory assessments and ultrasonography. All the participants were invited to have a physical examination after a face-to-face interview. Fasting blood samples were obtained from the antecubital vein, and the samples were used for the analysis of biochemical values. Abdominal ultrasonography was conducted. RESULTS: A total of 10461 (7331 men and 3130 women) current and former petrochemical employees attended for screening. The overall prevalence of post-cholecystectomy, gallstones and PLGs was 0.9%, 5.2% and 7.4%, respectively. Compared with the increased prevalence of either gallstones or post-cholecystectomy in older persons, PLGs were more common in the middle-aged, peaking in those aged 40-59 years. Excluding the patients with gallstones, gallstones mixed with PLGs, or those who had undergone cholecystectomy, in the remaining 9828 participants, the prevalence of PLGs in men (8.9%) was significantly higher than that in women (5.5%, P < 0.001). The analyzed risk factors with increased OR for the development of PLGs were male gender (OR = 1.799, P < 0.001), age ≥ 30 years (OR = 2.699, P < 0.001) and hepatitis B surface antigen (HBsAg) positivity (OR = 1.374, P = 0.006). CONCLUSION: PLGs are not rare among Chinese petrochemical employees. Male gender, HBsAg positivity, and middle age are risk factors for developing PLGs.


Subject(s)
Gallbladder Diseases/epidemiology , Gallbladder/pathology , Gallstones/epidemiology , Occupational Health , Polyps/epidemiology , Adult , Aged , Aged, 80 and over , Blood Pressure , China/epidemiology , Extraction and Processing Industry , Female , Gallbladder/diagnostic imaging , Gallbladder Diseases/diagnostic imaging , Health Surveys , Hepatitis B Surface Antigens , Humans , Male , Middle Aged , Occupational Exposure , Odds Ratio , Petroleum , Polyps/diagnostic imaging , Prevalence , Risk Factors , Surveys and Questionnaires , Ultrasonography , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...