Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Phys Chem Chem Phys ; 26(5): 4329-4337, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38234282

RESUMO

Spin-dependent transport in ferromagnet/organic-ferromagnet/ferromagnet junctions is investigated theoretically under different alignment of magnetization orientations. The results demonstrate a significant current rectification at low bias voltages, and the rectifying direction relies on the relative magnetization orientation in each component. The orbital analysis demonstrates two underlying mechanisms for the rectification, the slight structural asymmetry of the molecule from spin radicals and distinct spin match between conducting electrons and the magnetic molecule upon the reversal of bias. The latter is responsible for the strong low-bias rectification and relies on the magnetization alignment. The effects of parameter strength, temperature and size on the rectification are discussed. This work explores a new route to achieve high-performance molecular rectifiers operating at low bias with controlled rectifying direction.

2.
J Phys Chem Lett ; 14(1): 132-138, 2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36576489

RESUMO

The limitation of suitable anomalous valley Hall effect (AVHE) materials has seriously hindered the booming development and the widespread application of valleytronics. Here, through the first-principles calculations, we propose a MXene monolayer Y3N2O2 with spontaneous valley polarization (VP) of 21.3 meV, which induces intrinsic AVHE. The VP can be modulated linearly, which provides a route of effective control of the valley signals. Importantly, VP can be enhanced by adjusting up the spin-orbit coupling (SOC) based on a SOC Hamiltonian model and the first-principles calculations. From this physics underlying, we substitute the Y atom with the La atom and further propose the monolayer La3N2O2, in which the heavy atom La will provide stronger SOC than Y atom. The spontaneous VP in La3N2O2 is enhanced to 100.4 meV, so AVHE can be easily achieved. Our work not only provides compelling candidates for AVHE materials but also offers a novel mindset for finding suitable valleytronic devices.

3.
Front Chem ; 10: 861838, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35273953

RESUMO

In this work, we study the electronic structure, the effective mass, and the optical properties of the MoSSe/InS van der Waals heterostructures (vdWHs) by first-principles calculations. The results indicate that the MoSSe/InS vdWH is an indirect band gap semiconductor and has type-Ⅱ band alignment in which the electrons and holes located at the InS and the MoSSe side, respectively. The band edge position, the band gap and the optical absorption of the MoSSe/InS vdWH can be tuned when biaxial strains are applied. In addition, compared with MoSSe and InS monolayers, the optical absorption of the MoSSe/InS vdWH is improved both in the visible and the ultraviolet regions. These findings indicate that the MoSSe/InS vdWHs have potential applications in optoelectronic devices.

4.
Sci Rep ; 10(1): 4028, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32132623

RESUMO

Based on the density functional theory, the electronic and optical properties of pristine monolayer PdSe2 with Pd or Se vacancy-defect are investigated. Our results show that the Se defect is energetically more favorable than that of Pd defect. The band gap reduces, and some new midgap states appear after the Pd or Se defects are introduced. In terms of the optical properties, the prominent anisotropic characters are remained. The obvious new peaks of the dielectric constant appear after introducing defects. The light absorption in the visible energy range expands based on the appearance of the midgap states induced by the Pd or Se defects. The changes of the refractive index and reflectivity are similar with those of the dielectric constants and the light absorption. The energy loss spectrum of the PdSe2 with Pd or Se defects is obviously different, which can be used to identify different defects in PdSe2. These findings provide effective strategies to tune electronic and optical properties of monolayer PdSe2 by introducing defects.

5.
J Biol Regul Homeost Agents ; 30(3): 827-831, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27655506

RESUMO

There is growing evidence that vitamin D (VitD) plays a role in the pathophysiological mechanism of every patient undergoing hemodialysis, and this role is significantly altered in a microinflammatory state. However, it is unclear whether supplementation dosage or route of administration should be altered due to this state. Thus, the objective of our mini review and meta-analysis was to re-consider supplementation of VitD in HD patients exhibiting micro-inflammatory state. Pubmed, Web of Science and Google Scholar were searched up to January 19, 2016. We included studies that evaluated supplementation in HD patients with micro-inflammatory state. One reviewer extracted data and one reviewer verified the data accuracy. We qualitatively summarized the main results and meta-analyzed data on comparable outcomes across studies. The main outcome measures were serum levels of VitD. Ten eligible studies were published between 2002 and 2016, involving a total 1,239 patients. Average vintage of hemodialysis was 35.36 (±31.08) months. We identified a high degree of clinical diversity (interventions and outcomes) and methodological heterogeneity (sample size and risk of bias) in included trials. The studies we reviewed provide some weak evidence to support VitD supplementation in patients on hemodialysis exhibiting micro-inflammatory state. We recommend that future trials focus on our main outcome measures (that is variable comparable across studies).


Assuntos
Inflamação/tratamento farmacológico , Diálise Renal , Vitamina D/uso terapêutico , Viés , Proteína C-Reativa/análise , Calcitriol/administração & dosagem , Calcitriol/uso terapêutico , Feminino , Humanos , Inflamação/etiologia , Inflamação/fisiopatologia , Interleucina-6/sangue , Falência Renal Crônica/sangue , Falência Renal Crônica/terapia , Masculino , Diálise Renal/efeitos adversos , Projetos de Pesquisa , Tamanho da Amostra , Vitamina D/sangue , Vitamina D/fisiologia
6.
Tech Coloproctol ; 20(8): 551-7, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27194235

RESUMO

BACKGROUND: Medical treatments for irritable bowel syndrome (IBS) are often disappointing. A colonic irrigation system, the Ashong colonic irrigation apparatus (ACIA), was designed as a patient-administered device for defecation disorders. This pilot study evaluated the efficacy and safety of ACIA for IBS. METHODS: Eighteen patients, 12 with constipation-dominant IBS (IBS-C) and 6 with diarrhea-dominant IBS (IBS-D) group, were studied. Patients were randomized into treatments of 1-4 weeks. Colonic irrigation was performed twice daily for 6 consecutive days per week. To determine the response to treatment, bowel movement frequency, stool consistency, abdominal pain, patient satisfaction with bowel movements, and distress/discomfort due to symptoms were assessed. RESULTS: The scores of abdominal pain (p < 0.001), satisfaction (p < 0.001), and distress/discomfort (p < 0.001) improved significantly. The frequency of bowel movements in the IBS-C group increased from 1.68 to 3.78 times per week (p < 0.001). The occurrence of Bristol Stool Scale type 1 and 2 stool passage decreased from 45 to 13 % (p = 0.009) in the IBS-C group and type 6 and 7 stools decreased from 62 to 28 % (p = 0.005) in the IBS-D group. Only mild adverse events occurred, and all patients completed treatment. CONCLUSIONS: Colonic irrigation with ACIA is safe and can improve abdominal pain, constipation, and diarrhea associated with IBS. Patients were more satisfied with their bowel movements and found their symptoms were less disturbing. Larger studies on long-term efficacy and quality of life and on placebo effects are needed.


Assuntos
Colo , Síndrome do Intestino Irritável/terapia , Irrigação Terapêutica/instrumentação , Dor Abdominal/etiologia , Adulto , Constipação Intestinal/etiologia , Defecação , Diarreia/etiologia , Fezes , Feminino , Humanos , Síndrome do Intestino Irritável/complicações , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Projetos Piloto , Avaliação de Sintomas , Resultado do Tratamento , Adulto Jovem
7.
Opt Express ; 23(10): 13554-61, 2015 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-26074603

RESUMO

Ga2O3 photodetectors with interdigitated electrodes have been designed and fabricated, and the Ga2O3 area exposed to illumination acts as the active layer of the photodetector, while the area covered by Au interdigital electrode provide an arena for carrier multiplication. The photodetectors show a maximum responsivity at around 255 nm and a cutoff wavelength of 260 nm, which lies in the solar-blind region. The responsivity of the photodetector reaches 17 A/W when the bias voltage is 20 V, which corresponds to a quantum efficiency of 8228%, amongst the best value ever reported in Ga2O3 film based solar-blind photodetectors.

8.
Epidemiol Infect ; 143(14): 3001-10, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25778999

RESUMO

This study characterized Neisseria meningitidis serogroup C strains in China in order to establish their genetic relatedness and describe the use of multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) to provide useful epidemiological information. A total of 215 N. meningitidis serogroup C strains, obtained from 2003 to 2012 in China, were characterized by MLVA with different published schemes as well as multilocus sequence typing. (i) Based on the MLVA scheme with a combination of five highly variable loci, 203 genotypes were identified; this level of discrimination supports its use for resolving closely related isolates. (ii) Based on a combination of ten low variable loci, clear phylogenetic relationships were established within sequence type complexes. In addition, there was evidence of microevolution of VNTR loci over the decade as strain lineages spread from Anhui to other provinces, the more distant the provinces from Anhui, the higher the genetic variation.


Assuntos
Genótipo , Infecções Meningocócicas/microbiologia , Repetições Minissatélites , Tipagem Molecular/métodos , Neisseria meningitidis Sorogrupo C/classificação , Neisseria meningitidis Sorogrupo C/genética , China/epidemiologia , Humanos , Infecções Meningocócicas/epidemiologia , Epidemiologia Molecular/métodos , Neisseria meningitidis Sorogrupo C/isolamento & purificação
9.
Braz. j. med. biol. res ; 47(12): 1062-1067, 12/2014. graf
Artigo em Inglês | LILACS | ID: lil-727659

RESUMO

The aim of this study was to investigate the effect of propofol pretreatment on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the role of the phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) pathway in this procedure. Survival was determined 48 h after LPS injection. At 1 h after LPS challenge, the lung wet- to dry-weight ratio was examined, and concentrations of protein, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) were determined using the bicinchoninic acid method or ELISA. Lung injury was assayed via lung histological examination. PI3K and p-Akt expression levels in the lung tissue were determined by Western blotting. Propofol pretreatment prolonged survival, decreased the concentrations of protein, TNF-α, and IL-6 in BALF, attenuated ALI, and increased PI3K and p-Akt expression in the lung tissue of LPS-challenged rats, whereas treatment with wortmannin, a PI3K/Akt pathway specific inhibitor, blunted this effect. Our study indicates that propofol pretreatment attenuated LPS-induced ALI, partly by activation of the PI3K/Akt pathway.


Assuntos
Animais , Masculino , Lesão Pulmonar Aguda/tratamento farmacológico , /metabolismo , Propofol/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/enzimologia , Lesão Pulmonar Aguda/metabolismo , Western Blotting , Líquido da Lavagem Broncoalveolar/química , Ensaio de Imunoadsorção Enzimática , Indicadores e Reagentes , /análise , Estimativa de Kaplan-Meier , Lipopolissacarídeos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Propofol/metabolismo , Quinolinas , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/metabolismo
10.
Braz J Med Biol Res ; 47(12): 1062-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25387673

RESUMO

The aim of this study was to investigate the effect of propofol pretreatment on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the role of the phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) pathway in this procedure. Survival was determined 48 h after LPS injection. At 1 h after LPS challenge, the lung wet- to dry-weight ratio was examined, and concentrations of protein, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) were determined using the bicinchoninic acid method or ELISA. Lung injury was assayed via lung histological examination. PI3K and p-Akt expression levels in the lung tissue were determined by Western blotting. Propofol pretreatment prolonged survival, decreased the concentrations of protein, TNF-α, and IL-6 in BALF, attenuated ALI, and increased PI3K and p-Akt expression in the lung tissue of LPS-challenged rats, whereas treatment with wortmannin, a PI3K/Akt pathway specific inhibitor, blunted this effect. Our study indicates that propofol pretreatment attenuated LPS-induced ALI, partly by activation of the PI3K/Akt pathway.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Fosfatidilinositol 3-Quinases/metabolismo , Propofol/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/enzimologia , Lesão Pulmonar Aguda/metabolismo , Animais , Western Blotting , Líquido da Lavagem Broncoalveolar/química , Ensaio de Imunoadsorção Enzimática , Indicadores e Reagentes , Interleucina-6/análise , Estimativa de Kaplan-Meier , Lipopolissacarídeos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Masculino , Propofol/metabolismo , Quinolinas , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/metabolismo
11.
Eur J Neurol ; 19(6): 884-91, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22289016

RESUMO

BACKGROUND AND PURPOSE: Previous studies demonstrated that post-stroke hyperglycemia was associated with poor outcome in non-diabetic patients. However, evidence was inconclusive amongst patients with diabetes. The aim of this study was to evaluate the relationship between initial glucose levels and mortality amongst patients with acute ischaemic stroke, and further, to assess whether the association varied by diabetes mellitus and glycated hemoglobin (HbA(1c) ) levels. METHODS: Data were collected from the medical records of 1277 first-ever stroke patients admitted to the emergency room between January 1, 2008 and June 30, 2009. Cox regression analysis was performed to assess the relationship between initial glucose level and mortality. RESULTS: Compared with the lowest quartile of initial glucose level, a significant association with all-cause death [hazard ratio (HR), 2.18; 95% CI, 1.36-3.48] and cardiovascular death (HR, 1.91; 95% CI, 1.01-3.61) was seen in the highest quartile. In non-diabetic subgroup, those patients within the highest quartile of initial glucose level had a 3.29-fold relative risks (RR) [95% confidence interval (CI), 1.62-6.68] for all-cause and a 2.54-fold RR (95% CI, 1.43-8.77) for cardiovascular death compared with those within the lowest quartile. However, the association between initial glucose levels and the risk of death was not significant amongst those with diabetes (P for interaction = 0.01). In addition, the risk amongst patients with diabetes varied by the HbA(1c) levels. CONCLUSIONS: A significant association was confirmed between initial glucose level and mortality in non-diabetic ischaemic stroke patients. The possible relationship between initial glucose level, HbA(1c) level, and mortality amongst ischaemic stroke patients with diabetes warrants further research.


Assuntos
Glicemia/metabolismo , Causas de Morte , Diabetes Mellitus/mortalidade , Hemoglobinas Glicadas/metabolismo , Acidente Vascular Cerebral/mortalidade , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/mortalidade , Diabetes Mellitus/sangue , Diabetes Mellitus/epidemiologia , Feminino , Seguimentos , Humanos , Hiperglicemia/epidemiologia , Hiperglicemia/etiologia , Incidência , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/epidemiologia , Taxa de Sobrevida
12.
Sheng Wu Gong Cheng Xue Bao ; 17(3): 288-92, 2001 May.
Artigo em Chinês | MEDLINE | ID: mdl-11517602

RESUMO

An efficient and rapid gene transformation system of rice mediated by Agrobacterium tumefaciens was used. Calli induced from immature and mature embryos of Zhonghua No. 11, a japonic rice variety, were cultured with the A. tumefaciens strain EHA105 harboring the superbinary plasmid pDsBar1300 or pUBITs separately, and more than 400 independent transgenic lines inserted Ds element or Ac fragment were obtained. Some visible mutants in T0 or T1 generation were found, consisting of disease resistance, albino, dwarf, male sterile, chlorosis, early heading, late heading, stripe, etc. From the phenotype analysis, a few mutants such as dwarf and male sterile seemed to be linked to the Basta resistance and the transposon.


Assuntos
Elementos de DNA Transponíveis , Mutação , Oryza/genética , Zea mays/genética , Agrobacterium tumefaciens/genética , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase , Técnica de Amplificação ao Acaso de DNA Polimórfico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...