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1.
Zhonghua Gan Zang Bing Za Zhi ; 29(8): 776-780, 2021 Aug 20.
Artigo em Chinês | MEDLINE | ID: mdl-34517460

RESUMO

Objective: To investigate the long-term characteristic changes of virus, immune status, and liver fibrosis markers in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) co-infected patients after receiving direct-antiviral agents (DAAs). Methods: HIV/HCV co-infected patients who visited the Guangzhou Eighth People's Hospital, Guangzhou Medical University from May 2014 to December 2019 were selected as the research subjects. The changes of virological response rate, peripheral blood CD4(+)T lymphocyte level and serological markers of liver fibrosis (APRI score and FIB-4 index) were observed during 144 weeks of follow-up course after the end of DAAs treatment. Kruskal-Wallis test was used for statistical approach. Results: A total of 103 cases were included in the study. There were 87 males (87.5%), with a median age of 44 years. Sustained virological response rate at 12 weeks (SVR12) after DAAs treatment was 97.6%, and the SVR during the entire follow-up period was at least 95.9%. Compared with baseline, CD4(+)T lymphocyte count were significantly increased equally at 12 weeks (Z = -2.283, P = 0.022), 24 weeks (Z = -3.538, P < 0.001), 48 weeks (Z = -3.297, P = 0.001), 96 weeks (Z = -3.562, P < 0.001), and 144 weeks (Z = -2.842, P = 0.004). APRI score (Z = -6.394, P < 0.001) and FIB-4 index (Z = -2.528, P = 0.011) were significantly lower than baseline at week 4 of DAAs treatment, and thereafter remained at a low level, without further declination. Conclusion: HIV/HCV co-infected patients can maintain high SVR for a long time, acquire good immune reconstitution, and significantly improve liver fibrosis after DAAs treatment.


Assuntos
Coinfecção , Infecções por HIV , Hepatite C Crônica , Hepatite C , Adulto , Antivirais/uso terapêutico , Coinfecção/tratamento farmacológico , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Hepacivirus , Hepatite C/tratamento farmacológico , Hepatite C Crônica/tratamento farmacológico , Humanos , Cirrose Hepática/tratamento farmacológico , Masculino , Resultado do Tratamento
2.
HIV Med ; 21(11): 729-738, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33369035

RESUMO

OBJECTIVES: Talaromycosis is an invasive mycosis endemic to Southeast Asia. This study aimed to investigate the epidemiology, clinical features and prognostic factors of HIV-associated talaromycosis in Guangdong, China. METHODS: We retrospectively evaluated HIV patients hospitalized with histopathology- or culture-confirmed talaromycosis between 2011 and 2017. Factors associated with poor prognosis were identified using logistic regression. RESULTS: Overall, 1079 patients with HIV-associated talaromycosis were evaluated. Both the number and prevalence of talaromycosis among HIV admissions increased from 125 and 15.7% in 2011 to 253 and 18.8% in 2017, respectively, reflecting the increase in HIV admissions. Annual admissions peaked during the rainy season between March and August. Common clinical manifestations included fever (85.6%), peripheral lymphadenopathy (72.3%), respiratory symptoms (60.8%), weight loss (49.8%), skin lesions (44.5%) and gastrointestinal symptoms (44.3%). Common laboratory abnormalities were hypoalbuminaemia (98.6%), anaemia (95.6%), elevated aspartate aminotransferase level (AST) (76.9%), elevated alkaline phosphatase level (55.8%) and thrombocytopenia (53.7%). The median CD4 count was 9 cells/µL. Talaromyces marneffei was isolated from blood and bone marrow cultures of 66.6% and 74.5% of patients, respectively. The rate increased to 86.6% when both cultures were performed concurrently. At discharge, 14% of patients showed worsening conditions or died. Leucocytosis, thrombocytopenia, elevated AST, total bilirubin, creatinine and azole monotherapy independently predicted poor prognosis. CONCLUSIONS: The incidence of HIV-associated talaromycosis has increased in Guangdong with the high HIV burden in China. Skin lesions were seen in less than half of patients. Induction therapy with azole alone is associated with higher mortality. Findings from this study should help to improve treatment of the disease.

3.
Zhonghua Nei Ke Za Zhi ; 59(0): E012, 2020 May 09.
Artigo em Chinês | MEDLINE | ID: mdl-32388937

RESUMO

Objective: To evaluate the efficacy and safety of lopinavir/ritonavir (LPV/r) and arbidol in the treatment of COVID-19 in the real world. Methods: The clinical data of 178 patients diagnosed with COVID-19 admitted to Guangzhou Eighth People's Hospital were retrospectively analyzed from January 21 to February 9, 2020. According to the patient's antiviral treatment regimen, 178 patients were divided into 4 groups including LPV/r group (59 patients), arbidol group (36 patients), combination therapy with LPV/r plus arbidol group (25 patients) and the conventional treatment group without any antiviral drugs (58 patients). The main observation end points of the study was the negative conversion time of nucleic acid of the novel coronavirus (2019-nCoV) in pharyngeal swab. Results: The baseline of 4 groups before treatment was consistent and comparable. The negative conversion time of nucleic acid of the 2019-nCoV in pharyngeal swab was (10.20 ± 3.49), (10.11 ± 4.68), (10.86 ± 4.74), (8.44 ± 3.51) days separately in the LPV/r group, the arbidol group, the combination therapy group, and the conventional treatment group without significant difference (F = 2.556, P = 0.058). There was also no significant difference in the rate of negative conversion rate of 2019-nCoV nucleic acid, the improvement ration in clinical symptoms, and the improvement ration of pulmonary infection in the lung CT imaging (P> 0.05). However, a statistically significant difference was found in the proportion of deterioration changing from mild/moderate to severe/critical type at day 7 (χ(2) = 9.311, P = 0.017) as follows: the combination therapy group (24.0%, 6/25), the arbidol group ( 16.7%, 6/36), LPV/r group (5.4%, 3/56) and conventional treatment group (5.2%, 3/58). Moreover, the frequency of adverse reactions in the three groups receiving antiviral drugs was significantly higher than that in the conventional treatment group (χ(2) = 14.875, P = 0.002). Conclusions: No evidences could prove that LPV/r and arbidol could shorten the negative conversion time of novel coronavirus nucleic acid in pharyngeal swab nor improve the symptoms of patients. Furthermore, the combination usage of LPV/r and arbidol may not benefit for improving the disease. Noteworthy, the adverse reactions of the antiviral drugs should be paid careful attention during the treatment.

4.
Clin Biomech (Bristol, Avon) ; 79: 104947, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-31959394

RESUMO

BACKGROUND: Progressive pseudorheumatoid dysplasia is a rare skeletal dysplasia mainly caused by abnormal autosomal recessive inheritance. Although the main function of cartilage is mechanical support and the characteristics of this disease is the degradation of AC, previous studies on it had been mainly focused on clinical and genetic aspects and the mechanical behavior of the cartilage affected by PPRD is still ambiguous. In this study, we investigate the mechanics and structure of the cartilage suffered disease at multi-scale, from individual chondrocytes to the bulk-scale tissue. METHODS: Depth-sensing indenter were employed to investigate the mechanics of cartilage; we performed atomic force microscope nanoindentation to investigate the cell mechanics and scanning electron microscopy were used to explore the structure feature and chemical composition. FINDINGS: The elastic modulus of chondrocytes harvested from cartilage suffered from progressive pseudorheumatoid dysplasia is significantly higher than from normal cartilage, same trend were also found in tissue level. Moreover, denser collagen meshwork and matrix calcification were also observed. INTERPRETATION: The elastic modulus of cartilage should closely related to its denser structure and the calcification, and may potentially be an indicator for clinical diagnosis. The stiffening of chondrocytes during PPRD progression should play a rather important role in its pathogenesis.


Assuntos
Cartilagem Articular/patologia , Progressão da Doença , Artropatias/congênito , Fenômenos Mecânicos , Fenômenos Biomecânicos , Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Condrócitos/patologia , Colágeno/metabolismo , Módulo de Elasticidade , Humanos , Artropatias/metabolismo , Artropatias/patologia
5.
J Anim Sci ; 96(8): 3221-3232, 2018 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-29992325

RESUMO

The objective of the study was to investigate the effect of feeding reduced CP, AA-supplemented diets on meat quality in growing and finishing pigs as well as the related mechanism. In experiment 1, 18 growing pigs (36.5 kg BW) were assigned randomly and fed 1 of 3 corn-soybean meal diets containing either 18% CP (normal protein, NP), 15% CP (low protein, LP), or 12% CP (very low protein, VLP). In experiment 2, 18 finishing pigs (62.3 kg BW) were allotted randomly into 1 of the following diets: 16% CP (NP), 13% CP (LP), or 10% CP (VLP). In both experiments, the LP and VLP diets were supplemented with crystalline AA to achieve equal content of standardized ileal digestible lysine, methionine, threonine, and tryptophan. At the end of each experiment, all pigs were slaughtered to collect longissimus dorsi muscle (LM) samples. Samples were used for determining meat quality, intramuscular fat (IMF) content, fatty acid composition, free AA profile, and expression of genes for myosin heavy chain isoforms. Results showed that growing and finishing pigs fed the LP diets increased (P < 0.05) redness value of LM, while finishing pigs fed the LP and VLP diets decreased (P < 0.05) the shear force values. Compared with the NP diet, growing and finishing pigs fed lower CP diets had higher (P < 0.05) contents of IMF and MUFA, and lower (P < 0.05) contents of PUFA. Besides, higher (P < 0.05) expression levels of type I and/or IIa muscle fibers were observed in LP diet-fed growing and finishing pigs, and greater concentrations of taurine and tasty AA in VLP diet-fed growing and finishing pigs. Taken together, our results indicate that low-protein diets could positively affect meat quality of growing and finishing pigs, and likely through regulation of IMF content and fatty acid composition, fiber characteristics, and free AA profile in the muscle.


Assuntos
Dieta com Restrição de Proteínas , Fibras na Dieta , Suplementos Nutricionais , Metabolismo dos Lipídeos , Carne Vermelha/normas , Suínos/metabolismo , Aminoácidos/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Ácidos Graxos/metabolismo , Feminino , Íleo/metabolismo , Lisina/metabolismo , Masculino , Músculos/metabolismo , Distribuição Aleatória , Soja , Suínos/crescimento & desenvolvimento
6.
J Anim Physiol Anim Nutr (Berl) ; 102(1): e43-e51, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28266085

RESUMO

Liver metabolism is affected by nutrients. The aim of this study was to explore the effects of low-protein diets (17% crude protein, CP) supplemented with branched-chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile) and valine (Val), on hepatic amino acid profile and lipid metabolism in growing pigs. The ratio of Leu : Ile : Val in all groups was 1 : 0.51 : 0.63 (20% crude protein, CP), 1 : 1 : 1 (17% CP), 1 : 0.75 : 0.75 (17% CP), 1 : 0.51 : 0.63 (17% CP) and 1 : 0.25 : 0.25 (17% CP) respectively. Results revealed that compared to the positive control group (1 : 0.51 : 0.63, 20% CP), the low-protein diets significantly augmented the concentrations of most essential amino acids and non-essential amino acids (p < .05), with the greatest values observed in the 1 : 0.25 : 0.25 group. Moreover, relative to the control, the low-protein diets with the Leu : Ile : Val ratio ranging from 1 : 0.75 : 0.75 to 1 : 0.25 : 0.25 markedly downregulated the mRNA abundance of acetyl-CoA carboxylase (ACC), lipoprotein lipase (LPL) and fatty acid-binding protein 4 (FABP-4) (p < .05), and upregulated the mRNA expression of hormone-sensitive lipase (HSL), peroxisome proliferator-activated receptor-g coactivator-1α (PGC-1α), uncoupling protein 3 (UCP3) and liver carnitine palmitoyltransferase 1 (L-CPT-1) (p < .05). Therefore, our data suggest that protein-restricted diets supplemented with optimal BCAA ratio, that is, 1 : 0.75 : 0.75-1 : 0.25 : 0.25, induce a shift from fatty acid synthesis to fatty acid oxidation in the liver of growing pigs. These effects may be associated with increased mitochondrial biogenesis.


Assuntos
Aminoácidos/metabolismo , Proteínas na Dieta/administração & dosagem , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Fígado/metabolismo , Suínos/fisiologia , Aminoácidos/administração & dosagem , Aminoácidos/sangue , Animais , Mitocôndrias/metabolismo , Oxirredução , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
7.
Carbohydr Polym ; 170: 217-225, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28521989

RESUMO

Osteoarthritis (OA) is the most prevalent musculoskeletal disorder and the leading cause of joint disability in elderly patients. In this study, we fabricated strontium chondroitin sulfate (SrCS), a new polysaccharide-metal ion complex that is the combination of chondroitin sulfate and strontium, which are two widely adopted chemicals in OA clinical management. The structural, chemical compositions and morphology of as-fabricated SrCS were systematically investigated. Cell proliferation test, RT-PCR and preliminary animal studies were conducted to evaluate the clinical potential of SrCS on OA treatment. The materials characterization results verified that the Sr was successfully integrated into CS by replacing sodium in the original structure and formed a new polysaccharide-metal ion complex. The cell proliferation results indicated that the SrCS has excellent biocompatibility for both chondrocyte and osteoblast. The RT-PCR results showed that the SrCS can significantly increase the expression of COLII and ACAN, decrease MMP1 and MMP13 in chondrocyte and decrease the IL-6 and IL-1ß in both chondrocyte and osteoblast. Preliminary animal studies demonstrated that SrCS can effectively simulate the articular cartilage formation in SD-rats after modified Hulth's OA modeling surgery. We therefore believed that the SrCS should be a rather effective chemical for OA clinical management as well as a beneficial component for various biomaterials in cartilage tissue engineering.


Assuntos
Condrócitos/efeitos dos fármacos , Sulfatos de Condroitina/síntese química , Sulfatos de Condroitina/farmacologia , Osteoartrite/fisiopatologia , Estrôncio/química , Animais , Cartilagem Articular/efeitos dos fármacos , Humanos , Ratos
8.
J Anim Sci ; 94(12): 5192-5205, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28046182

RESUMO

The objective of the study was to explore the extent to which the dietary CP level can be reduced for maintaining muscle protein deposition in growing pigs as well as the related mechanism and whether the response to dietary protein restriction is diversely modified throughout the 2 trial periods. A total of 36 pigs (9.57 ± 0.64 kg initial BW) were individually penned and fed 1 of 3 diets for 10 or 25 d. During each period, the diets contained 20, 17, and 14% CP, respectively. Both the 17% CP diet and the 14% CP diet were supplemented with Lys, Met, Thr, and Trp to provide the same total concentrations as those in the 20% CP diet. Results showed that feeding the 14% CP diet for 10 or 25 d seriously impaired ( < 0.05) growth performance of the pigs compared with those fed the 20 or 17% CP diets. Pigs fed the 20% CP diet for 25 d had a higher ( < 0.05) serum content of urea nitrogen than those fed the 17 and 14% CP diets. In addition, the free AA (FAA) profile in skeletal muscle of the pigs was evidently changed ( < 0.05) by the low-protein diets for 25 d; of note, the 14% CP diet increased ( < 0.05) the size of muscle FAA pool compared with the 20% CP diet. Meanwhile, on d 25, reducing dietary CP levels also influenced ( < 0.05) mRNA levels of specific AA transceptors expressed in skeletal muscle, especially revealing the striking differences between the 14 and 20% CP diet-fed pigs. Most importantly, we observed a globally decreased ( < 0.05) activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway in skeletal muscle of pigs fed the 14% CP diet, whereas only partial inhibition was observed for those fed the 17% CP diet compared with those fed the 20% CP diet. However, feeding the low-protein diets for 10 d had minimal effects on serum parameters, muscle FAA profile, and muscle mTORC1 pathway of the pigs. Taken together, our results indicate that supplementing with limiting AA to the 14% CP diet is not highly effective for the pigs in restoring protein synthesis and muscle growth, whereas the 17% CP diet likely maintains the pigs' muscle mass, which were regulated, at least in part, by mediating AA transceptors expression, FAA profile, and activation of the mTORC1 pathway.


Assuntos
Aminoácidos/metabolismo , Dieta com Restrição de Proteínas/veterinária , Suínos/fisiologia , Aminoácidos/análise , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Vias Biossintéticas/efeitos dos fármacos , Nitrogênio da Ureia Sanguínea , Dieta/veterinária , Suplementos Nutricionais , Feminino , Músculo Esquelético/metabolismo
9.
Osteoarthritis Cartilage ; 23(4): 516-24, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25463446

RESUMO

Mounting evidence suggests reconceptualizing osteoarthritis (OA) as an inflammatory disorder. Trauma and obesity, the common risk factors of OA, could trigger the local or systemic inflammatory cytokines cascade. Inflammatory bone loss has been well documented; yet it remains largely unknown about the link between the inflammation and hypertrophic changes of subchondral bone seen in OA, such as osteophytosis and sclerosis. Amid a cohort of inflammatory cytokines, endothelin-1 (ET-1) could stimulate the osteoblast-mediated bone formation in both physiological (postnatal growth of trabecular bone) and pathological conditions (bone metastasis of prostate or breast cancer). Also, ET-1 is known as a mitogen and contributes to fibrosis in various organs, e.g., skin, liver, lung, kidney heart and etc., as a result of inflammatory or metabolic disorders. Subchondral bone sclerosis shared the similarity with fibrosis in terms of the overproduction of collagen type I. We postulated that ET-1 might have a hand in the subchondral bone sclerosis of OA. Meanwhile, ET-1 was also able to stimulate the production of matrix metalloproteinase (MMP)-1 and 13 by articular chondrocytes and synoviocytes, by which it might trigger the enzymatic degradation of articular cartilage. Taken together, ET-1 signaling may play a role in destruction of bone-cartilage unit in the pathogenesis of OA; it warrants further investigations to potentiate ET-1 as a novel diagnostic biomarker and therapeutic target for rescue of OA.


Assuntos
Cartilagem/fisiopatologia , Endotelina-1/fisiologia , Osteoartrite/etiologia , Osteoartrite/fisiopatologia , Osteogênese/fisiologia , Esclerose/fisiopatologia , Remodelação Óssea/fisiologia , Condrócitos/fisiologia , Citocinas/fisiologia , Humanos , Metaloproteinase 1 da Matriz/fisiologia , Metaloproteinase 13 da Matriz/fisiologia , Transdução de Sinais/fisiologia
10.
Osteoarthritis Cartilage ; 21(11): 1716-23, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23831668

RESUMO

OBJECTIVES: This study aimed to characterize subchondral bone damages of knee osteoarthritis (OA) patients in presence of the comorbidities, i.e., hypertension and type 2 diabetes mellitus (T2DM). METHODS: A total of 43 patients with advanced stage of primary knee OA were recruited, and tibial plateau specimens were collected during surgery with informed consent. The specimens were processed for micro-CT and histological examination to assess the severity of subchondral bone damages. The presence of the comorbid disease, e.g., hypertension and T2DM, and the data on covariates, such as the age, gender and body mass index (BMI), were taken into account in a multi-variable linear regression model to explore the potential effect of the comorbidities on subchondral bone damages in knee OA after adjusting the covariates. RESULTS: As compared to 15 subjects without the comorbidities, significant bone loss was observed at subchondral plate in 28 knee OA patients with hypertension and T2DM, in terms of the lower bone mineral density (BMD) (P = 0.034) and higher porosity (P = 0.032) on the medial portion of tibial plateau. After adjusting the age, gender and BMI, the presence of hypertension or T2DM was included in a regression model to explain in part the decreased BMD (r(2) = 0.551, P = 0.004) and increased porosity (r(2) = 0.545, P = 0.003) at subchondral plate in knee OA. CONCLUSION: Our findings suggest the biological link between bone loss at subchondral bone plate in knee OA and the comorbid diseases, i.e., hypertension and T2DM, which prompt the needs for a large-scale cohort study to confirm the causality.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Hipertensão/complicações , Osteoartrite do Joelho/complicações , Osteoporose/etiologia , Tíbia/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/fisiologia , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/patologia , Osteoartrite do Joelho/fisiopatologia , Osteoporose/patologia , Osteoporose/fisiopatologia , Porosidade , Tíbia/patologia , Microtomografia por Raio-X/métodos
11.
Osteoarthritis Cartilage ; 21(4): 574-81, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23313833

RESUMO

OBJECTIVE: This study aimed to investigate the spatial and temporal subchondral bone change of Dunkin-Hartley (DH) strain guinea pigs spontaneous osteoarthritis (OA) model at early stage with three-dimensional Microfocal Computed Tomography (Micro-CT) analysis, histology and immunohistochemistry. MATERIALS AND METHODS: Knee joints of DH and Bristol Strain 2 (BS2) guinea pigs were analyzed at 1, 2 and 3 months of age for early staged subchondral bone ultrastructure change of OA by Micro-CT and histology. And cartilage degeneration was monitored by histological examination. In addition, expression of Osterix was quantified by immunohistochemistry. RESULTS: Microscopic cartilage degeneration was not found at first 3 months in both DH and BS2 guinea pigs. Subchondral bone sclerosis with trabecular ultrastructure turnover was characterized in subchondral bone of DH guinea pigs. Increased thickness, bone mineral density with decreased porosity were defined in subchondral plate of DH guinea pigs. Subchondral trabecular bone was found to be plate-like, convex and isotropy with higher bone volume. Histology confirmed the finding of lower porosity at osteochondral junction and increased bone volume. Immunohistochemistry revealed that the early OA subchondral bone change may be due to elevated level of osteoblast differentiation. CONCLUSIONS: Subchondral bone ultrastructure change occurred at early stage of OA ahead of microscopic cartilage degeneration, which may further impair articular cartilage. It was possibly related to elevated level of osteoblast differentiation.


Assuntos
Artrite Experimental/patologia , Cartilagem Articular/patologia , Osteoartrite/patologia , Animais , Artrite Experimental/diagnóstico por imagem , Artrite Experimental/fisiopatologia , Densidade Óssea/fisiologia , Diferenciação Celular/fisiologia , Fêmur/diagnóstico por imagem , Fêmur/fisiopatologia , Fêmur/ultraestrutura , Cobaias , Osteoartrite/diagnóstico por imagem , Osteoartrite/fisiopatologia , Osteoblastos/patologia , Porosidade , Tíbia/diagnóstico por imagem , Tíbia/fisiopatologia , Tíbia/ultraestrutura , Microtomografia por Raio-X/métodos
12.
Nano Lett ; 12(11): 5867-72, 2012 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-23121486

RESUMO

Device integration on flexible or low-cost substrates has driven interest in the low-temperature growth of semiconductor nanostructures. Using in situ electron microscopy, we examine the Au-catalyzed growth of crystalline Ge at temperatures as low as 150 °C. For this materials system, the model for low temperature growth of nanowires, we find three distinct reaction pathways. The lowest temperature reactions are distinguished by the absence of any purely liquid state. From measurements of reaction rates and parameters such as supersaturation, we explain the sequence of pathways as arising from a kinetic competition between the imposed time scale for Ge addition and the inherent time scale for Ge nucleation. This enables an understanding of the conditions under which catalytic Ge growth can occur at very low temperatures, with implications for nanostructure formation on temperature-sensitive substrates.

13.
Osteoarthritis Cartilage ; 20(8): 916-22, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22548795

RESUMO

OBJECTIVE: This study aimed to characterize the in-situ mechanical property and morphology of individual collagen fibril in osteoarthritic cartilage using indentation-type atomic force microscopy (IT-AFM). METHODS: The specimens with intact articular cartilage (AC), mild to severe degenerated cartilage from osteoarthritis (OA) were collected with informed consent from the postmenopausal women who underwent hip or knee arthroplasty. The fresh specimens were cryo-sectioned by layers with 50µm thick for each from the articular surface to calcified cartilage, and then processed for AFM imaging and nanoindentation test. For each layer, a total of 20 collagen fibrils were randomly selected for testing. AFM tips with the nominal radius less than 10nm were employed for probing the individual collagen fibril, and the obtained cantilever deflection signal and displacement were recorded for calculating its elastic modulus. RESULTS: An intact AC exhibited a gradation in elastic modulus of collagen fibrils from articular surface (2.65 ± 0.31 GPa) to the cartilage-bone interface (3.70 ± 0.44 GPa). It was noted in mildly degenerated OA cartilage that the coefficient of variation for mechanical properties of collagen fibers, ranging from 25% to 48%, significantly increased as compared with intact one (12%). The stiffened collagen fibrils occurred at either articular surface (3.11 ± 0.91 GPa) or the cartilage-bone interface (5.64 ± 1.10 GPa), accompanied by loosely organized meshwork with advancement of OA cartilage degeneration. It was echoed by histological findings of OA cartilage, including fibrotic changes of surface region and tidemark irregularities. CONCLUSION: The stiffened collagen fibrils in AC occurred with OA onset and progression, not only at articular surface but also the cartilage-bone interface.


Assuntos
Cartilagem Articular/diagnóstico por imagem , Colágenos Fibrilares/ultraestrutura , Osteoartrite do Joelho/patologia , Adulto , Idoso , Feminino , Humanos , Microscopia de Força Atômica/métodos , Pessoa de Meia-Idade , Pós-Menopausa , Estresse Mecânico , Ultrassonografia
14.
Plant Dis ; 96(6): 913, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30727369

RESUMO

Winter jujube, Zizyphus jujuba Mill., is a Chinese crop with fruit that has an extremely high nutritional value (4). In early November 2010, a severe fruit rot affecting ~20% of 1,000 kg of winter jujube fruit was observed in a storehouse in Zhengzhou, Henan province, China. The same fruit rot symptoms were found in two supermarkets in Zhengzhou in late November 2010 in ~10% of 100 kg of fruit in one supermarket and 25% of 50 kg of fruit in the other. Symptoms first appeared as small, round, pale yellow brown lesions on the fruits, 1 to 3 mm in diameter, then developed into 5- to 10-mm, sunken, brown spots, each with a pale brown margin. Three Fusarium isolates (DZF001 to DZF003) showing similar morphological characteristics were isolated from three specimens (collected from one storehouse and two supermarkets) by surface sterilizing small pieces of necrotic fruit tissue for 1 min in 2% NaOCl, washing the tissue pieces three times with sterile distilled water, and plating the pieces on potato dextrose agar (PDA). Fungal colonies for each isolate were white to light pink, and the adaxial side of each culture was pale yellow. Macroconidia were produced in pale orange sporodochia and were slender, relatively straight, three to five septa, 29.0 to 55.2 × 2.5 to 4.0 µm, with a curved apical cell and a poorly developed basal cell. Microconidia were produced in chains or false heads on synthetic nutrient-poor agar, clavate with a planar base, aseptate, and 4.5 to 8.0 × 2.5 to 3.5 µm. Conidiophores terminated in verticils of two to three phialides or monophialides. Chlamydospores were absent. The cultural and morphological characteristics were similar to those of Fusarium proliferatum (1,2). The identity of the three fungal isolates was confirmed to be F. proliferatum by DNA sequencing of the internal transcribed spacer (ITS) rDNA region (GenBank Accession Nos. JN889713 to JN889715), which were 99 to 100% homologous to those of other F. proliferatum isolates (GU066714, HQ113948, and GU363955); and the elongation factor 1-alpha (EF-1a) gene (JN889713 to JN889715), which was 99% homologous to those of other F. proliferatum isolates (FJ538244, FJ895277, and GQ848536) (3). Pathogenicity tests were conducted on 20 winter jujube fruits using a mycelial plug harvested from the periphery of a 7-day-old colony of strain DZF001, and placed on the surface of the fruit after the inoculated area of the fruit had been surface sterilized with 75% ethanol for 2 min; an equal number of fresh winter jujube fruits treated with non-colonized plugs of PDA served as the control treatment. Each jujube fruit was pricked three times with an insect needle to create three holes close together before inoculation with an agar plug. Each fruit was then enclosed in a clear plastic box with a cup of sterile distilled water to maintain high relative humidity, and held at 25°C. Symptoms similar to those originally observed on the naturally infected fruit were observed 3 days after inoculation, and the same fungus was reisolated from each of the symptomatic fruits; control fruits remained asymptomatic and no fungus was isolated from the control fruit. Koch's postulates were repeated three times with the same results. To our knowledge, this is the first report of F. proliferatum causing rot of winter jujube fruit in China. References: (1) K. Chehri et al. Saudi J. Biol. Sci. 18:341, 2011. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual, Blackwell Publishing, 2006. (3) H. T. Phan. Studies Mycol. 50:261, 2004. (4) J. Sheng et al. Acta Hort. 620:203, 2003.

15.
Phys Rev Lett ; 107(2): 025503, 2011 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21797618

RESUMO

Nanowire growth in the standard <111> direction is assumed to occur at a planar catalyst-nanowire interface, but recent reports contradict this picture. Here we show that a nonplanar growth interface is, in fact, a general phenomenon. Both III-V and group IV nanowires show a distinct region at the trijunction with a different orientation whose size oscillates during growth, synchronized with step flow. We develop an explicit model for this structure that agrees well with experiment and shows that the oscillations provide a direct visualization of catalyst supersaturation. We discuss the implications for wire growth and structure.

16.
Nano Lett ; 10(2): 514-9, 2010 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-20041666

RESUMO

We use real-time observations of the growth of copper-catalyzed silicon nanowires to determine the nanowire growth mechanism directly and to quantify the growth kinetics of individual wires. Nanowires were grown in a transmission electron microscope using chemical vapor deposition on a copper-coated Si substrate. We show that the initial reaction is the formation of a silicide, eta'-Cu(3)Si, and that this solid silicide remains on the wire tips during growth so that growth is by the vapor-solid-solid mechanism. Individual wire directions and growth rates are related to the details of orientation relation and catalyst shape, leading to a rich morphology compared to vapor-liquid-solid grown nanowires. Furthermore, growth occurs by ledge propagation at the silicide/silicon interface, and the ledge propagation kinetics suggest that the solubility of precursor atoms in the catalyst is small, which is relevant to the fabrication of abrupt heterojunctions in nanowires.


Assuntos
Cobre/química , Nanopartículas/química , Nanotecnologia/métodos , Nanofios/química , Silício/química , Catálise , Cinética , Microscopia Eletrônica de Varredura/métodos , Microscopia Eletrônica de Transmissão/métodos , Pressão , Temperatura
17.
Phys Rev Lett ; 105(19): 195502, 2010 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-21231182

RESUMO

Nanowire growth occurs by step flow at the wire-catalyst interface, with strikingly different step-flow kinetics for solid versus liquid catalysts. Here we report quantitative in situ measurements of step flow together with a kinetic model that reproduces the behavior. This allows us to identify the key parameters controlling step-flow growth, evaluate changes in the catalyst composition during growth, and identify the most favorable conditions for growing abrupt heterojunctions in nanowires.

18.
Science ; 326(5957): 1247-50, 2009 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-19965471

RESUMO

We have formed compositionally abrupt interfaces in silicon-germanium (Si-Ge) and Si-SiGe heterostructure nanowires by using solid aluminum-gold alloy catalyst particles rather than the conventional liquid semiconductor-metal eutectic droplets. We demonstrated single interfaces that are defect-free and close to atomically abrupt, as well as quantum dots (i.e., Ge layers tens of atomic planes thick) embedded within Si wires. Real-time imaging of growth kinetics reveals that a low solubility of Si and Ge in the solid particle accounts for the interfacial abruptness. Solid catalysts that can form functional group IV nanowire-based structures may yield an extended range of electronic applications.

19.
Phys Rev Lett ; 103(15): 155701, 2009 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-19905650

RESUMO

The phase diagram of a nanoscale system can be substantially different than in the bulk, but quantitative measurements have proven elusive. Here we use in situ microscopy to observe a phase transition in a nanoscale system, together with a simple quantitative model to extract the size effects from these measurements. We expose a Au particle to disilane gas, and observe the transition from a two-phase Au + AuSi system to single-phase AuSi. Size effects are evident in the nonlinear disappearance of the solid Au. Our analysis shows a substantial shift in the liquidus line, and a discontinuous change in the liquid composition at the transition. It also lets us estimate the liquid-solid interfacial free energy.

20.
Forensic Sci Int ; 140(2-3): 217-32, 2004 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-15036443

RESUMO

Image fusion is a process of combining two or more images into an image. It can extract features from source images, and provide more information than one image can. Multi-resolution analysis plays an important role in image processing, it provides a technique to decompose an image and extract information from coarse to fine scales. In some practical forensic examinations (such as the cartridge image check), we cannot obtain all information from just one image; on the contrary, we need information from images with difference light sources (or light ways). In this paper, we apply an image fusion method based on multi-resolution analysis to forensic science. Synthetic and real images (such as images from closed-up photography and flash photography) are used to show the capability of the multi-resolution image fusion technique.


Assuntos
Crime , Ciências Forenses/métodos , Fotografação/métodos , Processamento de Sinais Assistido por Computador , Humanos
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