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1.
Aging (Albany NY) ; 16(5): 4282-4298, 2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38441529

RESUMO

White matter hyperintensities (WMH) and gamma-aminobutyric acid (GABA) are associated with executive function. Multiple studies suggested cortical alterations mediate WMH-related cognitive decline. The aim of this study was to investigate the crucial role of cortical GABA in the WMH patients. In the 87 WMH patients (46 mild and 41 moderate to severe) examined in this study, GABA levels in the anterior cingulate cortex (ACC) and posterior cingulate cortex (PCC) assessed by the Meshcher-Garwood point resolved spectroscopy (MEGA-PRESS) sequence, WMH volume and executive function were compared between the two groups. Partial correlation and mediation analyses were carried out to examine the GABA levels in mediating the association between WMH volume and executive function. Patients with moderate to severe WMH had lower GABA+/Cr in the ACC (p = 0.034) and worse executive function (p = 0.004) than mild WMH patients. In all WMH cases, the GABA+/Cr levels in the ACC mediated the negative correlation between WMH and executive function (ab: effect = -0.020, BootSE = 0.010, 95% CI: -0.042 to -0.004). This finding suggested GABA+/Cr levels in the ACC might serve as a protective factor or potential target for preventing the occurrence and progression of executive function decline in WMH people.


Assuntos
Disfunção Cognitiva , Substância Branca , Humanos , Função Executiva , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Disfunção Cognitiva/psicologia , Ácido gama-Aminobutírico
2.
Biol Res Nurs ; 26(3): 390-398, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38407112

RESUMO

Background: Constipation is common in elderly inpatients with intracerebral hemorrhage. This study aimed to construct a model for predicting the risk of constipation in elderly inpatients with intracerebral hemorrhage and to provide reference for formulating targeted intervention measures. Methods: Elderly patients with intracerebral hemorrhage who were treated in the department of Neurosurgery of a third-class hospital in Suzhou from January 2018 to September 2023 were included. Clinical data of patients with and without constipation were compared. Logistic regression analysis was used to explore the influencing factors of constipation in elderly patients with intracerebral hemorrhage, and R software was used to construct a line chart model to verify its predictive effect. Results: A total of 504 elderly patients with intracerebral hemorrhage were included. The incidence of constipation in elderly patients with cerebral hemorrhage was 63.9%. Logistic regression analysis showed that GCS score (OR = 1.094, 95%CI: 1.019∼1.174), hypertension (OR = 2.911, 95%CI: 1.797∼4.715), use of dehydrating agent (OR = 3.794, 95%CI: 2.337∼6.158), surgical treatment (OR = 3.986, 95%CI: 2.339∼6.793), use of sedative drugs (OR = 4.212, 95%CI:2.386-7.435), and limb paralysis (OR = 6.313, 95%CI:3.689∼10.803) were the independent risk factors for constipation in elderly patients with intracerebral hemorrhage. The area under the ROC curve of the prediction model was 0.872 (95%CI: 0.8401∼0.9033), the best critical value was 0.705, the sensitivity was 0.748, and the specificity was 0.857. Conclusion: The constipation risk prediction model of elderly patients with cerebral hemorrhage has good differentiation and calibration, which is helpful for health care providers to identify the risk of constipation in elderly patients with intracerebral hemorrhage.


Assuntos
Hemorragia Cerebral , Constipação Intestinal , Humanos , Hemorragia Cerebral/complicações , Idoso , Feminino , Masculino , Constipação Intestinal/epidemiologia , Fatores de Risco , Idoso de 80 Anos ou mais , China/epidemiologia , Pessoa de Meia-Idade , Incidência
3.
Eur J Med Res ; 29(1): 35, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38185655

RESUMO

Breast cancer (BC) is one of the most common malignancies in women and the leading cause of cancer-related death in women. The newly emerged non-coding RNAs tsRNAs (tRNA-derived small RNAs) play an important role in the occurrence and development of BC. The purpose of this study was to comprehensively evaluate the prognostic, diagnostic and clinicopathological roles of tsRNAs in BC. Through literature screening, a total of 13 BC-related tsRNA studies were included in this meta-analysis, all of which passed quality assessment. Prognostic studies showed upregulated tsRNAs to be associated with poor survival outcomes (HR = 1.64, 95%CI 1.51-1.77) and downregulated tsRNAs to be associated with better outcomes (HR = 0.58, 95%CI 0.50-0.68). Results of diagnostic studies showed a combined sensitivity of 72% (95%CI 68-76%) and combined specificity of 64% (95%CI 61-67%); the AUC was 0.72 (95%CI 0.68-0.75) and the DOR 4.62 (95%CI 3.76-5.68). Finally, correlation analysis of clinicopathological features showed that downregulation of tsRNAs correlated significantly with age, TNM stage and lymphatic metastasis. Sensitivity analysis and publication bias showed no significant difference. In conclusion, BC-associated tsRNAs are closely related to the prognosis and clinicopathological features of patients with this disease and can be used to assist in early diagnosis of BC. Therefore, tsRNAs are potential targets for the diagnosis and treatment of BC.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Prognóstico , RNA
5.
Chemosphere ; 308(Pt 1): 136177, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36037939

RESUMO

Anaerobic digestates were potential mediums for cultivating oleaginous microalgae, but their various components brought uncertainties for aglal growth and lipids production. In this study, three microalgae strains were tested to grow on four typical anaerobic digestates. The results showed that anaerobic food wastewater was an optimal medium for C. pyrenoidosa and S. obliquus culture (N. oleoabundanst cannot survive), achieving the highest biomass (2.15-2.32 g L-1) and lipids production (20.6-32.5 mg L-1·d-1). In contrast, three microalgae strains could grow suboptimally in anaerobic municipal (0.79-0.95 g L-1) and toilet (0.92-1.40 g L-1) wastewater, but showed poor performances in anaerobic swine wastewater. The growth of microalgae removed 40.9-63.4% of TOC, 83.7-96.3% of NH4+-N and 70.3-89.4% of TP in the three ADs. In addition, it was unfortunately found that the lipids content and saturation degree in fatty acids significantly decreased in ADs with sufficient nutrients. It suggests that some measures should be taken to balance biomass, lipids production and quality for cultivating microalgae in anaerobic digestates.


Assuntos
Poluentes Ambientais , Microalgas , Anaerobiose , Animais , Biomassa , Ácidos Graxos , Suínos , Águas Residuárias
6.
J Neurosci Methods ; 370: 109488, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35090903

RESUMO

BACKGROUND: Arterial spin labeling magnetic resonance imaging (ASL MRI) is a noninvasive technique to measure cerebral blood flow (CBF). It is widely used in the study of neurodegenerative diseases. Image denoising is an important step in ASL image processing because the signal-to-noise ratio (SNR) of an ASL CBF perfusion image is very small. NEW METHOD: We propose a new ASL image denoising method that exploits patch-based low-rank and sparse tensor decomposition and a non-local means filter. COMPARISON WITH EXISTING METHODS: The proposed method was compared with two existing ASL denoising methods: component-based noise correction method (CompCor) and low-rank and sparse matrix decomposition-based ASL image denoising method (LS-ASLd). RESULTS: Various image quality measures, namely SNR, tSNR and ASL CBF variance, show that the proposed method is more effective than existing ASL denoising methods. The proposed method was used to denoise images from a resting state ASL dataset to compute brain functional connectivity (FC) and images from a task-related ASL dataset to identify brain activation. The results show that the proposed denoising method is more effective to enhance the sensitivity of ASL CBF series when undertaking CBF time series-based FC analysis and task activation detection. CONCLUSIONS: Assessment of the performance of the proposed hybrid ASL CBF image denoising method confirms that it is especially well-suited to FC analysis and sensorimotor task analysis.


Assuntos
Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Razão Sinal-Ruído , Marcadores de Spin
7.
Int J Clin Pract ; 75(10): e14537, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34132007

RESUMO

OBJECTIVE: To examine the association between hip and knee osteoarthritis (OA) and falls. Potentially relevant articles that examine the association between hip, knee, radiological, and self-reported OA and falls were retrieved from PubMed, EMBASE, Scopus, and Web of Science up until March of 2020. METHODS: The pooled risk ratios (RRs) as well as their related 95% confidence intervals (CIs) were calculated. Statistic and subgroup analyses were performed. A total of 21 studies involving 146 965 participants were included. RESULTS: No association was found between hip OA and falls. The pooled RRs value suggested a higher prevalence of falls in knee OA patients (RR = 1.35, 95% CI: 1.20 to 1.51, P < .00001) and self-reported OA (RR = 1.33, 95% CI: 1.23 to 1.45, P < .00001) than in non-OA subjects. The pooled RR value suggested no difference between prevalence of falls in radiological OA patients compared to non-OA subjects (RR = 1.82, 95% CI: 0.89 to 3.73, P = .10). Both radiological and self-reported knee OA seem to be positively associated with falls, while no obvious association was found between hip OA and falls. CONCLUSIONS: Therefore, knee OA is a risk factor for falls which should be closely monitored.


Assuntos
Osteoartrite do Quadril , Osteoartrite do Joelho , Humanos , Articulação do Joelho , Osteoartrite do Quadril/complicações , Osteoartrite do Quadril/epidemiologia , Osteoartrite do Joelho/complicações , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/epidemiologia , Prevalência , Fatores de Risco
8.
World J Clin Cases ; 9(16): 4007-4015, 2021 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34141760

RESUMO

BACKGROUND: Tuberculosis (TB) is a widespread infectious disease, with an incidence that is increasing worldwide. Cutaneous TB (CTB) occurs rarely, accounting for less than 1% of all TB cases. Due to the clinical presentation and diagnostic difficulties, CTB is often clinically neglected and misdiagnosed. CASE SUMMARY: A 32-year-old man underwent several debridement surgeries and skin flap transplantation after trauma. The wound remained unhealed, accompanied by sinus formation. According to empirical judgment, T-cell spot of TB test, and bacterial culture of pyogenic fluids, he was diagnosed with CTB due to infection with exogenous Mycobacterium tuberculosis. A comprehensive anti-TB regimen that included isoniazid, rifampicin, ethambutol, and pyrazinamide was applied. The sinus was filled with a hydrophilic fiber-containing silver dressing, and wound-protecting sponges were applied to part of the wound. The wound healed after 40 d. No ulceration was found within 2 mo after discharge; further follow-up will be conducted. CONCLUSION: A non-healing wound may be caused by TB infection. Comprehensive treatment of CTB is effective.

9.
Entropy (Basel) ; 23(6)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34074036

RESUMO

Entropy indicates irregularity or randomness of a dynamic system. Over the decades, entropy calculated at different scales of the system through subsampling or coarse graining has been used as a surrogate measure of system complexity. One popular multi-scale entropy analysis is the multi-scale sample entropy (MSE), which calculates entropy through the sample entropy (SampEn) formula at each time scale. SampEn is defined by the "logarithmic likelihood" that a small section (within a window of a length m) of the data "matches" with other sections will still "match" the others if the section window length increases by one. "Match" is defined by a threshold of r times standard deviation of the entire time series. A problem of current MSE algorithm is that SampEn calculations at different scales are based on the same matching threshold defined by the original time series but data standard deviation actually changes with the subsampling scales. Using a fixed threshold will automatically introduce systematic bias to the calculation results. The purpose of this paper is to mathematically present this systematic bias and to provide methods for correcting it. Our work will help the large MSE user community avoiding introducing the bias to their multi-scale SampEn calculation results.

10.
Holist Nurs Pract ; 34(2): 103-112, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049696

RESUMO

Auricular acupressure (AA) is widely used in East Asia and Europe to manage patients with sleep disturbance. This feasibility study was performed to demonstrate the potential of AA for sleep disturbance in patients with leukemia. Thirty-two patients with leukemia with poor sleep quality received AA 3 times a day for a total of 4 weeks. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality at baseline, at a 2-week intervention, and after a 4-week intervention. Compared with baseline scores, PSQI scores and the use of sleep medicine were significantly improved at week 2 and week 4 (P < .05). As a potential safety therapy, AA could be an alternative or complementary intervention to improve sleep quality for patients with leukemia with sleep disturbance.


Assuntos
Acupressão/normas , Cápsula Articular , Leucemia/terapia , Transtornos do Sono-Vigília/terapia , Acupressão/métodos , Acupressão/estatística & dados numéricos , Adulto , Tratamento Farmacológico/métodos , Tratamento Farmacológico/psicologia , Estudos de Viabilidade , Feminino , Humanos , Leucemia/psicologia , Masculino , Pessoa de Meia-Idade , Transtornos do Sono-Vigília/psicologia , Resultado do Tratamento
11.
Anal Chem ; 89(24): 13415-13421, 2017 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-29120609

RESUMO

Carbon isotopes have been widely used in tracing a wide variety of geological and environmental processes. The carbon isotope composition of bulk rocks and minerals was conventionally analyzed by isotope ratio mass spectrometry (IRMS), and, more recently, secondary ionization mass spectrometry (SIMS) has been widely used to determine carbon isotope composition of carbon-bearing solid materials with good spatial resolution. Here, we present a new method that couples a RESOlution S155 193 nm laser ablation system with a Nu Plasma II MC-ICP-MS, with the aim of measuring carbon isotopes in situ in carbonate minerals (i.e., calcite and aragonite). Under routine operating conditions for δ13C analysis, instrumental bias generally drifts by 0.8‰-2.0‰ in a typical analytical session of 2-3 h. Using a magmatic calcite as the standard, the carbon isotopic composition was determined for a suite of calcite samples with δ13C values in the range of -6.94‰ to 1.48‰. The obtained δ13C data are comparable to IRMS values. The combined standard uncertainty for magmatic calcite is <0.3‰ (1s). No significant matrix effects have been identified in calcite with the amplitude of chemical composition variation (i.e., MnO, SrO, MgO, or FeO) up to 2.5 wt %. Two modern corals were investigated using magmatic calcite as the calibration standard, and the average δ13C values for both corals are similar to the bulk IRMS values. Moreover, coral exhibits significant heterogeneity in carbon isotope compositions, with differences up to 4.85‰ within an individual coral. This study indicates that LA-MC-ICP-MS can serve as an appropriate method to analyze carbon isotopes of carbonate minerals in situ.


Assuntos
Carbonato de Cálcio/análise , Isótopos de Carbono , Terapia a Laser , Espectrometria de Massas
12.
Medicine (Baltimore) ; 95(43): e5215, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27787383

RESUMO

BACKGROUND: Short-stem (SS) prostheses require less resection of the femoral neck, produce a more physiological load pattern in the proximal femur, reduce stress shielding, and aid bone conservation and are, therefore, beneficial for young patients. Conventional cementless implants in total hip arthroplasty (THA) have shown excellent clinical results; however, it is unclear whether SS prostheses can obtain the same clinical and radiological outcomes. We conducted a meta-analysis of randomized controlled trials (RCTs) to evaluate whether SS prostheses are superior to conventional implants after primary THA. METHODS: We reviewed the literature published up to June 2016 from PubMed, Web of Science, and the Cochrane Library to find relevant RCTs comparing SSs and conventional stems in primary THA. Quality assessment was performed by 2 independent reviewers. The RevMan 5.3 software program of the Cochrane Collaboration was used to analyze the data. Random- or fixed-effect models were used to calculate standardized mean differences (SMDs) and 95% confidence intervals (CIs) for each comparison. RESULTS: Six RCTs involving 552 patients with 572 hips were identified. Strong evidence indicated that SS prostheses were more effective for reducing thigh pain than conventional implants (I = 46%, P = 0.002; risk ratio [RR], 95% CI 0.15, 0.04-0.49). However, there were no significant differences between the 2 groups in Harris Hip Scores (I = 0%, P = 0.84; SMD, 95% CI 0.02, -0.15-0.18), Western Ontario and McMaster Universities Osteoarthritis Index Scores (I = 0%, P = 0.35; SMD, 95% CI 0.09, -0.10-0.27), femoral offset of stem (I = 0%, P = 0.57; SMD, 95% CI 0.06, -0.16-0.29), and leg-length discrepancy (I = 79%, P = 0.88; SMD, 95% CI 0.04, -0.44-0.51). CONCLUSION: SS prostheses achieve the same clinical and radiological outcomes as conventional implants, and were superior in terms of reducing thigh pain. But whether the postoperative thigh pain applied in 2nd-generation cementless prosthesis still needs further large-scale multicenter studies with longer follow-up to confirm.


Assuntos
Artroplastia de Quadril/instrumentação , Prótese de Quadril , Ensaios Clínicos Controlados Aleatórios como Assunto , Humanos , Desenho de Prótese , Resultado do Tratamento
13.
J Colloid Interface Sci ; 423: 85-93, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24703672

RESUMO

Hydrophilic nisin-loaded hydrophobic poly (lactic acid) (PLA) particles with controlled size and shape were successfully produced utilizing a one-step single emulsification method. Preliminary shear stress and temperature tests showed that there was no significant loss in the nisin inhibition activity during this process. PLA/nisin composite particles were prepared into solid nanocomposite spheres (50-200 nm) or hollow microcomposite spheres (1-5 µm) under the operative conditions developed in our previous study, in which the hydrophilic nisin in the aqueous phase solution could be entrapped in the hydrophobic polymer in the emulsification process generating either single or multiple emulsions. The incorporation of nisin in PLA had little effect on key processing conditions, which allows the dynamic control of the morphology and property of resulting particles. Microscopic and surface analyses suggested that nisin was dispersed uniformly inside the polymer matrix and adsorbed on the particle surface. The encapsulation amount and efficiency were enhanced with the increase in nisin loading in the aqueous solution. Unique reversible control of particle size and shape by this process was successfully applied in the nisin encapsulation. Alternating temperature in the repeating emulsification steps improved the encapsulation efficiency while generated particles in desired size and shape.


Assuntos
Antibacterianos/administração & dosagem , Portadores de Fármacos/química , Emulsões/química , Ácido Láctico/química , Nisina/administração & dosagem , Polímeros/química , Sequência de Aminoácidos , Antibacterianos/química , Antibacterianos/farmacologia , Humanos , Listeria monocytogenes/efeitos dos fármacos , Listeriose/tratamento farmacológico , Microesferas , Dados de Sequência Molecular , Nisina/química , Nisina/farmacologia , Tamanho da Partícula , Poliésteres
14.
J Colloid Interface Sci ; 409: 219-26, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23957926

RESUMO

The supramolecular self-assembly of polyelectrolyte multilayers (PEMs) provides robust bottom-up strategies to assemble a broad spectrum of nanostructures on the host substrates. In this study, we discuss the formation of graphene nanoplatelet (GNP) embedded polyelectrolyte films to enhance the oxygen barrier properties of poly(ethylene terephthalate) (PET) films. Despite cheaper costs and high mechanical strength, the diffusion of small gas molecules such as oxygen through PET films remains a matter of great concern. The simple yet robust supramolecular deposition of GNP/polyelectrolyte on PET substrates significantly increases the tortuous path the oxygen molecule has to travel, making it harder to diffuse through the PET film. With permeability coefficients in the range of 10-18 cc cm/cm(2) s Pa, the coatings developed in this study show three orders of magnitude reduction as compared to the permeability coefficient of the bare PET film, significantly lower than that of ethylene vinyl alcohol (EVOH) and comparable to silicon oxide thin films used in commercial gas barrier foils. The use of GNPs in the multilayered films also helped reduce the electrical sheet resistance to about 1MΩ which is five orders of magnitude lower than the original PET substrate opening up promising opportunities for future use in semiconductor and electronics industry. Making suitable modifications in the deposition process, three configurations of GNP embedded PEM multilayers namely hydrogen bonded, electrostatic, and composite films were developed and their effect on oxygen barrier property and sheet resistance was monitored. Oxygen permeability of films was tested in accordance with ASTM D-3985 using a MOCON 2/21 ML instrument, whereas electrical sheet resistance was quantified using a Gamry Femtostat Electrochemical Impedance station.

15.
Biotechnol Bioeng ; 110(8): 2123-30, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23456729

RESUMO

Cellulase, xylanase, and ß-glucosidase production was studied on novel nano-shear pretreated corn stover by the mixed fungi culture. The high shear force from a modified Tayor-Couette nano-shear mixing reactor efficiently disintegrated corn stover, resulting in a homogeneous watery mash with particles in much reduced size. Scanning electron microscope study showed visible mini-pores on the fiber cell wall surface, which could improve the accessibility of the pretreated corn stover to microorganisms. Mixed fungal culture of Trichoderma reesei RUT-C30 and Aspergillus niger produced enzymes with higher cellulolytic and xylanolytic activities on corn stover pretreated with nano-shear mixing reactor, in comparison with other pretreatment methods, including acid and ammonia fiber explosion (AFEX) pretreatment. The hydrolytic potential of the whole fermentation broth from the mixed fungi was studied, and the possibility of applying the whole cell saccharification concept was also investigated to further reduce the cost of lignocellulose hydrolysis.


Assuntos
Aspergillus niger/metabolismo , Celulase/metabolismo , Lignina/metabolismo , Trichoderma/metabolismo , Xilosidases/metabolismo , beta-Glucosidase/metabolismo , Aspergillus niger/crescimento & desenvolvimento , Biomassa , Celulase/isolamento & purificação , Hidrólise , Fenômenos Físicos , Trichoderma/crescimento & desenvolvimento , Xilosidases/isolamento & purificação , Zea mays/metabolismo , beta-Glucosidase/isolamento & purificação
16.
Biotechnol Lett ; 35(2): 181-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23070625

RESUMO

The use of immobilized enzymes during saccharification of lignocelluloses enables the continuous process of enzymatic hydrolysis and repeatable use of enzyme, resulting in reduced operational cost. Novel nano-biocarriers were developed by layer-by-layer deposition of carbon nanotube (CNT) on the foam structures, and their efficiency for enzyme immobilization was demonstrated with cellulase and ß-glucosidase. A three-fold enhancement was achieved in the activity of cellulase immobilized on CNT coated polyurethane foam. In addition, both cellulase and ß-glucosidase immobilized on the CNT-foam showed much better storage stability and operational stability than the ones immobilized on the commercial biocarrier (Celite), which is critical for a continuous operation. CNT coated monolith was also developed as a biocarrier, offering high surface area and geometric stability. These nano-biocarriers are promising candidates for the efficient saccharification of biomass and to reduce carbon footprint and cost of the equipment.


Assuntos
Portadores de Fármacos , Enzimas Imobilizadas/metabolismo , Lignina/metabolismo , Nanotubos de Carbono , Celulose/metabolismo , Hidrólise , beta-Glucosidase/metabolismo
17.
Appl Biochem Biotechnol ; 163(7): 869-81, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20859703

RESUMO

Diminishing fossil fuel reserve and increasing cost of fossil hydrocarbon products have rekindled worldwide effort on conversion of lignocellloloses (plant biomass) to renewable fuel. Inedible plant materials such as grass, agricultural, and logging residues are abundant renewable natural resources that can be converted to biofuel. In an effort to mimic natural cellulolytic-xylanolytic microbial community in bioprocessing of lignocelluloses, we enriched cellulolytic-xylanolytic microorganisms, purified 19 monocultures and evaluated their cellulolytic-xylanolytic potential. Five selected isolates (DB1, DB2, DB7, DB8, and DB13) were used to compose a defined consortium and characterized by 16S ribosomal RNA gene sequence analysis. Nucleotide sequence blast analysis revealed that DB1, DB2, DB7, DB8, and DB13 were respectively similar to Pseudoxanthomonas byssovorax (99%), Microbacterium oxydans (99%), Bacillus sp. (99%), Ochrobactrum anthropi (98%), and Klebsiella trevisanii (99%). The isolates produced an array of cellulolytic-xylanolytic enzymes (filter paper cellulase, ß-glucosidase, xylanase, and ß-xylosidase), and significant activities were recorded in 30 min. Isolates DB1 and DB2 displayed the highest filter paper cellulase: 27.83 and 31.22 U mg⁻¹, respectively. The highest ß-glucosidase activity (18.07 U mg⁻¹) was detected in the culture of isolate DB1. Isolate DB2 produced the highest xylanase activity (103.05 U mg⁻¹), while the highest ß-xylosidase activity (7.72 U mg⁻¹) was observed with DB13. Use of microbial consortium in bioprocessing of lignocelluloses could reduce problems such as incomplete synergistic enzymes, end-product inhibition, adsorption, and requirement for high amounts of enzymes in direct use of enzymes.


Assuntos
Bactérias/enzimologia , Biocombustíveis , Celulase/metabolismo , Consórcios Microbianos , Xilosidases/metabolismo , beta-Glucosidase/metabolismo , Bactérias/classificação , Fenômenos Fisiológicos Bacterianos , Técnicas de Tipagem Bacteriana , Sequência de Bases , Biomassa , Celulose/metabolismo , Fermentação , Interações Microbianas , Dados de Sequência Molecular , Filogenia , Poaceae/metabolismo , Polissacarídeos/metabolismo , RNA Ribossômico 16S/análise , Xilanos/metabolismo
18.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 25(4): 335-7, 2009 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-19351505

RESUMO

AIM: To purify cytotoxin from Agkitrodon acutus venom, and study the lethal effect of cytotoxin on gastric cancer cells and their ultrastructure changes. METHODS: The cytotoxin was isolated and purified with successive chromatography on DEAE-Sephadex A-50 and TSKgel Pheny columns from Agkitrodon acutus venom. The feasibility of BGC-823 cells assessed using the MTT assay. The ultrastructure of BGC-823 cells treated with the cytotoxin was observed with the scanning and transmission electron microscope. RESULTS: The purified cytotoxin H1 killed the gastric cancer cells. The cancer cell membrane and nuclear envelope were broken, mitochondria were swollen and intracellular substances were leaked out. CONCLUSION: The cytotoxin from Agkitrodon acutus venom can kill the gastric cancer cells effectively.


Assuntos
Apoptose/efeitos dos fármacos , Venenos de Crotalídeos/química , Citotoxinas/farmacologia , Animais , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , Sobrevivência Celular/efeitos dos fármacos , Citometria de Fluxo , Humanos , Microscopia Eletrônica de Transmissão , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/ultraestrutura , Membrana Nuclear/efeitos dos fármacos , Membrana Nuclear/ultraestrutura , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Neoplasias Gástricas/ultraestrutura
19.
ACS Nano ; 2(9): 1825-32, 2008 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-19206421

RESUMO

We report the novel fabrication of a highly sensitive, selective, fast responding, and affordable amperometric glucose biosensor using exfoliated graphite nanoplatelets (xGnPs) decorated with Pt and Pd nanoparticles. Nafion was used to solubilize metal-decorated graphite nanoplatelets, and a simple cast method with high content organic solvent (85 wt %) was used to prepare the biosensors. The addition of precious metal nanoparticles such as platinum (Pt) and palladium (Pd) to xGnP increased the electroactive area of the electrode and substantially decreased the overpotential in the detection of hydrogen peroxide. The Pt-xGnP glucose biosensor had a sensitivity of 61.5+/-0.6 microA/(mM x cm(2)) and gave a linear response up to 20 mM. The response time and detection limit (S/N=3) were determined to be 2 s and 1 microM, respectively. Therefore, this novel glucose biosensor based on the Pt nanoparticle coated xGnP is among the best reported to date in both sensing performance and production cost. In addition, the effects of metal nanoparticle loading and the particle size on the biosensor performance were systematically investigated.


Assuntos
Técnicas Biossensoriais/instrumentação , Glucose Oxidase/química , Glucose/análise , Grafite/química , Nanoestruturas/química , Paládio/química , Platina/química , Cristalização/métodos , Eletroquímica/instrumentação , Eletroquímica/métodos , Enzimas Imobilizadas/química , Desenho de Equipamento , Análise de Falha de Equipamento , Glucose/química , Substâncias Macromoleculares/química , Teste de Materiais , Microeletrodos , Conformação Molecular , Nanoestruturas/ultraestrutura , Nanotecnologia/instrumentação , Tamanho da Partícula , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Propriedades de Superfície
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