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1.
Environ Sci Pollut Res Int ; 31(19): 27980-27987, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38526713

RESUMO

The adsorption of ammonium from water was studied on an activated carbon obtained using raw oil palm shell and activated with acetic acid. The performance of this adsorbent was tested at different operating conditions including the solution pH, adsorbent dosage, and initial ammonium concentration. Kinetic and equilibrium studies were carried out, and their results were analyzed with different models. For the adsorption kinetics, the pseudo-first order equation was the best model to correlate this system. Calculated adsorption rate constants ranged from 0.071 to 0.074 g/mg min. The ammonium removal was 70-80% at pH 6-8, and it was significantly affected by electrostatic interaction forces. Ammonium removal (%) increased with the adsorbent dosage, and neutral pH condition favored the adsorption of this pollutant. The best ammonium adsorption conditions were identified with a response surface methodology model where the maximum removal was 91.49% with 2.27 g/L of adsorbent at pH 8.11 for an initial ammonium concentration of 36.90 mg/L. The application of a physical monolayer model developed by statistical physics theory indicated that the removal mechanism of ammonium was multi-ionic and involved physical interactions with adsorption energy of 29 kJ/mol. This activated carbon treated with acetic acid is promising to depollute aqueous solutions containing ammonium.


Assuntos
Ácido Acético , Compostos de Amônio , Poluentes Químicos da Água , Adsorção , Ácido Acético/química , Compostos de Amônio/química , Poluentes Químicos da Água/química , Cinética , Concentração de Íons de Hidrogênio , Arecaceae/química , Carvão Vegetal/química , Purificação da Água/métodos
2.
Food Chem ; 361: 130091, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34029902

RESUMO

Migration of silver nanoparticles (AgNPs) from food containers (FCs) has been assessed for the first time using a screening method previously validated. Migration was evaluated using water and 3% acetic acid as food simulants (FSs), from 20 to 70 °C at contact times of 2 h and 10 days. Total and migrated Ag were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in the FCs and FSs, respectively. Then, the screening method was validated, and probability of detection (POD) curves were constructed in both FSs to characterize the response to AgNPs. The results provided by the present screening method showed no release of AgNPs. The FSs in contact with FCs were spiked at levels above, inside and below the unreliability region, with a reliability rate (RLR) of 0.90. Asymmetric flow field flow fractionation coupled to inductively coupled plasma mass-spectrometry (AF4-ICP-MS) was used for confirmative analyses.


Assuntos
Embalagem de Alimentos , Espectrometria de Massas/métodos , Nanopartículas Metálicas/química , Prata/análise , Prata/química , Ácido Acético/química , Fracionamento por Campo e Fluxo , Tamanho da Partícula , Reprodutibilidade dos Testes , Fatores de Tempo , Água/química
3.
Int J Food Microbiol ; 336: 108904, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33129004

RESUMO

The aim of the present study was to determine the effects of organic fruit vinegars (blackberry, pomegranate, rosehip, and grape) used as marination liquids (MLs) on food-borne pathogens inoculated on beef, as well as on the quality characteristics (physical, chemical, microbiological and sensory properties) of beef during marination process at 4 °C for 24 h. In the first part of the study, meat samples separately inoculated with Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli O157:H7 (≅6 log CFU/mL) were marinated in four different MLs and the count of S. Typhimurium, L. monocytogenes and E. coli O157:H7 on samples decreased in the range of 1.040-1.225, 1.420-1.913 and 1.232-1.435 log CFU/g, respectively. Marination with rosehip vinegar (MLR) was determined as the most effective treatment against all pathogens. In the second part of the study, proximate composition, color parameters, cooking yield, marinate absorption, pH, texture profile, aerobic plate count and sensory properties of marinated meat samples were determined. The moisture content of the samples marinated with grape vinegar (MLG) (73.50%) was found lower than of the samples marinated with other formulations (in the range of 75.95-76.65%) (P < 0.05). Marination by various MLs resulted in significant differences between the L*, a* and b* values of meat samples (P < 0.05). The hardness value of the samples was decreased by marination with MLR (P < 0.05) and was determined as 25.70 N. There were no significant differences between the meat samples marinated with the four different MLs in terms of cooking yield, marinate absorption and pH (P > 0.05). Aerobic plate count was reduced in the range of 0.589-0.950 log CFU/g for 24 h marination (P > 0.05). The highest sensory evaluation scores in terms of flavor were determined in meat samples marinated with MLG (P > 0.05). Therefore, different fruit vinegars used as MLs improved the safety and quality of meat at different levels.


Assuntos
Ácido Acético/farmacologia , Culinária/métodos , Manipulação de Alimentos/métodos , Inocuidade dos Alimentos , Frutas/química , Ácido Acético/química , Animais , Bovinos , Contagem de Colônia Microbiana , Escherichia coli O157/efeitos dos fármacos , Manipulação de Alimentos/normas , Microbiologia de Alimentos , Listeria monocytogenes/efeitos dos fármacos , Carne Vermelha/normas , Salmonella typhimurium/efeitos dos fármacos , Vitis/química
4.
Regul Toxicol Pharmacol ; 114: 104656, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32437818

RESUMO

Additional non-animal methods are urgently needed to meet regulatory and animal welfare goals. TTC is a broadly used risk assessment tool. TTC based on external dose has limited utility for multi-route exposure and some types of structure activity relationship assessments. An internal TTC (iTTC), where thresholds are based on blood concentration, would extend the applicability of TTC. While work is on-going to develop robust iTTC thresholds, we propose an interim conservative iTTC. Specifically, an interim iTTC of 1 µM, supported by the published experience of the pharmaceutical industry, a literature review of non-drug chemical/receptor interactions, and analysis of ToxCast™ data. ToxCast™ data were used to explore activity versus the 1 µM interim iTTC and recommendations for the analysis and interpretation of HTS data. Test concentration-based points of departure were classified to identify quality of fit to the Hill Model. We identified, for exclusion from the approach, estrogen receptor and androgen receptor targets as potent chemical/receptor interactions potentially associated with low dose exposure to non-pharmaceutical active ingredients in addition to the original TTC exclusions. With these exclusions, we conclude that a 1 µM plasma concentration is unlikely to be associated with significant biological effects from chemicals not intentionally designed for biological activity.


Assuntos
Ácido Acético/efeitos adversos , Aspirina/efeitos adversos , Automação , Receptores Androgênicos/metabolismo , Ácido Salicílico/efeitos adversos , Ácido Acético/química , Ácido Acético/metabolismo , Animais , Aspirina/química , Aspirina/metabolismo , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Nível de Efeito Adverso não Observado , Receptores Androgênicos/química , Medição de Risco , Ácido Salicílico/química , Ácido Salicílico/metabolismo , Relação Estrutura-Atividade
5.
Bioanalysis ; 11(22): 2061-2074, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31829737

RESUMO

Aim: Neutralizing anti-drug antibody (NAb) assays are inherently prone to the interference from drug and its soluble target, potentially resulting in erroneous results. An effective approach to improve drug tolerance of an NAb assay is pretreatment of samples with acid to dissociate immune complexes of NAb and drug, followed by separating NAbs from circulating drug before testing them in the assay. Methods and Results: The acid pretreatment conditions were optimized to improve drug tolerance of cell-based and non-cell-based NAb assays. NAbs were further separated from circulating drug either through direct drug removal or purification of NAb from the sample. In addition, an integrated experimental strategy was implemented to simultaneously improve drug and its soluble target tolerance for reliable NAb assessment. Conclusion: The approaches described herein would enable the development of reliable NAb assays that overcome drug and its target interference for more precise and sensitive NAb assessment.


Assuntos
Anticorpos Neutralizantes/análise , Tolerância a Medicamentos/imunologia , Ácido Acético/química , Anticorpos Neutralizantes/química , Concentração de Íons de Hidrogênio
7.
Artigo em Inglês | MEDLINE | ID: mdl-31361183

RESUMO

A simultaneous headspace-gas chromatography/mass spectrometry (HS-GC/MS) method was developed and validated to determine the migration of 12 volatile organic compounds (methanol, acetone, methylethylketone, ethylacetate, isopropylalcohol, benzene, toluene, ethylbenzene, xylene, cumene, propylbenzene, and styrene) from food contact materials into food simulants (water, 4% acetic acid, 50% ethanol, and n-heptane). The limits of detection and quantification were 0.007-0.201 mg L-1 and 0.023-0.668 mg L-1, respectively. The method was applied to 205 samples of paper/paperboard, polyethylene, polypropylene, polystyrene, and polyethylene terephthalate. The estimated daily intake (EDI) was calculated using the migration results. Exposure assessments were carried out to compare the EDI to the tolerable daily intake (TDI); the results indicated that the EDI of styrene represented only a small percentage (8.0%) of the TDI. This analytical method will be a useful tool to examine levels of various volatile compounds migrating from food packaging to food simulants using HS-GC/MS method.


Assuntos
Análise de Alimentos , Contaminação de Alimentos/análise , Embalagem de Alimentos , Compostos Orgânicos Voláteis/análise , Ácido Acético/química , Etanol/química , Cromatografia Gasosa-Espectrometria de Massas , Heptanos/química , Temperatura , Água/química
8.
J Sci Food Agric ; 98(11): 4121-4127, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29393512

RESUMO

BACKGROUND: The aim of this study was to discriminate between commercial apple, rice, balsamic, red-wine, rose, white-wine, grape, and pomegranate vinegars according to their antimicrobial activities, total phenolic contents (TPC), antioxidant activities, and color parameters, and to predict the quality characteristics of vinegars using Fourier transform infrared (FTIR) spectroscopy. RESULTS: Results showed that the highest TPC (3971.43 ± 25.00) was found in balsamic vinegar whereas the lowest TPC was observed in rice vinegar (14.36 ± 0.16). Antioxidant activities of vinegars were correlated with TPC. Grape-based vinegars exhibited higher antimicrobial activity against Staphylococcus aureus (S. aureus), Escherichia coli (E.coli) and Pseudomonas aeruginosa (P.aeruginosa). However, there were no statistically significant differences among vinegars in terms of antimicrobial activities. According to principal component analysis (PCA) and hierarchical cluster analysis (HCA), vinegars were classified into three groups and each group consisted of vinegars from different raw materials. Prediction models were constructed successfully using partial least squares (PLS) considering whole FTIR spectral data. CONCLUSION: The results indicated that FTIR could be used as a rapid method to estimate the antimicrobial activities, TPC, color and antioxidant activities of vinegars. © 2018 Society of Chemical Industry.


Assuntos
Ácido Acético/química , Ácido Acético/farmacologia , Antibacterianos/química , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Ácido Acético/economia , Antibacterianos/economia , Antibacterianos/farmacologia , Malus/química , Oryza/química , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Vitis/química
9.
Molecules ; 22(11)2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29117097

RESUMO

5-fluorouracil (5-FU) is a specific anti-cancer agent that is generally used to treat gastrointestinal, colorectal, and breast cancer. In this work, chitosan (CS) was extracted from local fish scales using an established method. 5-FU was then converted to 1-acetic acid-5-fluorouracil (FUAC) and reacted with this CS to prepare chitosan-1-acetic acid-5-fluorouracil (CS-FUAC) conjugates as a colon-specific prodrug. All compounds were characterized by Proton nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared (FTIR), and UV-visible spectroscopy. The synthesized compound was subjected to a chemical stability study in phosphate buffer (0.2 M, pH 7.4) and in KCl/HCl buffer (0.2 M, pH 1.2) at different time intervals (0-240 min) and incubation at 37 °C. This revealed a significantly greater stability and a longer half-life for the CS-FUAC than for FUAC. Hemolytic activity results indicated a much lower toxicity for CS-FUAC than for 5-FU and supported consideration of CS-FUAC for further biological screening and application trials. The percentage of FUAC in the conjugates was determined by subjecting the prodrug to treatment in basic media to hydrolyze the amide bond, followed by absorbency measurements at 273 nm. The cytotoxicity studies of the conjugates were also evaluated on human colorectal cancer cell line (HT-29), which showed that the conjugates are more cytotoxic than the free drug. Therefore, CS-FUAC conjugates can be considered to represent potential colon-specific drug delivery agents, with minimal undesirable side effects, for colon cancer therapy.


Assuntos
Antineoplásicos , Quitosana , Neoplasias Colorretais/tratamento farmacológico , Fluoruracila , Pró-Fármacos , Ácido Acético/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Quitosana/análogos & derivados , Quitosana/síntese química , Quitosana/química , Quitosana/farmacologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Fluoruracila/química , Fluoruracila/farmacologia , Humanos , Pró-Fármacos/síntese química , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Coelhos
10.
Food Chem Toxicol ; 110 Suppl 1: S234-S241, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28576467

RESUMO

The use of this material under current conditions is supported by existing information. This material was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, as well as environmental safety. Data show that this material is not genotoxic. Data from the suitable read across analog isoamyl acetate (CAS# 123-92-2) show that this material does not have skin sensitization potential. The reproductive and local respiratory toxicity endpoints were completed using the TTC (Threshold of Toxicological Concern) for a Cramer Class I material (0.03 mg/kg/day and 1.4 mg/day, respectively). The repeated dose and developmental endpoint was completed using data on the target material, which provided a MOE > 100. The phototoxicity/photoallergenicity endpoint was completed based on suitable UV spectra. The environmental endpoint was completed as described in the RIFM Framework.


Assuntos
Ácido Acético/química , Ésteres/química , Perfumes/química , Animais , Química/organização & administração , Qualidade de Produtos para o Consumidor , Bases de Dados de Compostos Químicos , Humanos , Perfumes/toxicidade , Sistema de Registros
11.
J Gynecol Obstet Hum Reprod ; 46(4): 327-332, 2017 Apr.
Artigo em Francês | MEDLINE | ID: mdl-28643659

RESUMO

OBJECTIVES: To assess the implementation of a cervical cancer screening strategy in rural Madagascar. MATERIALS AND METHODS: A mobile unit, equipped with a cold-coagulator, visited every six months the main health care centers in the Atsinanana area between 2013 and 2015. Cervical cancer screening was based on visual inspection with acetic acid (VIA). The lesions suggestive of intraepithelial neoplasia and limited to the cervix were coagulated on the same day. Non-eligible patients for immediate treatment were referred for appropriate investigations. We assessed the feasibility and the coverage of the screening strategy and estimated the incidence of cervical cancer in the targeted population. RESULTS: One thousand five hundred and sixty-nine (18%) of 8959 women aged between 25 and 65 years old were screened. Three hundred and fifty-seven (23%) were VIA positive and 322 (21%) were eligible for immediate treatment. No serious adverse effects were observed among patients treated on the same day. Among the 35 patients not eligible for immediate treatment and referred to the hospital, 16 (46%) were lost to follow up. CONCLUSION: When a cervical cancer screening by HPV or cytology is not possible, VIA remains a feasible and acceptable option in a disadvantaged environment. The effectiveness of this approach is still limited by the problems of access to care for patients who are not eligible for immediate treatment.


Assuntos
Programas de Rastreamento , População Rural/estatística & dados numéricos , Neoplasias do Colo do Útero/diagnóstico , Ácido Acético/química , Adulto , Idoso , Colposcopia/estatística & dados numéricos , Detecção Precoce de Câncer/métodos , Detecção Precoce de Câncer/estatística & dados numéricos , Estudos de Viabilidade , Feminino , Implementação de Plano de Saúde/organização & administração , Implementação de Plano de Saúde/normas , Humanos , Incidência , Madagáscar/epidemiologia , Programas de Rastreamento/métodos , Programas de Rastreamento/organização & administração , Programas de Rastreamento/normas , Pessoa de Meia-Idade , Exame Físico/métodos , Serviços Preventivos de Saúde/métodos , Serviços Preventivos de Saúde/organização & administração , Neoplasias do Colo do Útero/epidemiologia , Esfregaço Vaginal , Displasia do Colo do Útero/diagnóstico , Displasia do Colo do Útero/epidemiologia
12.
Microsc Res Tech ; 80(4): 344-349, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28370969

RESUMO

The selection of an appropriate demineralizing solution in pathology laboratories depends on several factors such as the preservation of cellularity, urgency of diagnostic and financial costs. The aim of this study was to test different decalcification bone procedures in order to establish the best value of these in formalin-fixed and paraffin-embedded samples. Femurs were removed from 13 adult male Wistar rats to obtain 130 bone disks randomly divided into five groups that were demineralized in different concentrations of nitric acid (Group I); formic acid (Group II); acetic acid (Group III); EDTA, pH7.4 (Group IV) and Morsés solution (Group V). Serial, 3-µm-thick sections were obtained and stained with hematoxylin-eosin to calculate the percentage of osteocyte-occupied lacunae. The sections were also stained with Masson's trichrome in conjunction with picrosirius red under polarized light followed by a semi-quantitative analysis to verify the adjacent muscle-to-bone integrity and preservation of collagen fibres. The highest percentage of osteocyte-occupied lacunae was found with 10% acetic acid solution (95.64 ± 0.95%) and Group I (nitric acid) demanded the shorter time (0.8-5.7days). Of all solutions, 5% nitric acid incurred the lowest cost to achieve complete demineralization compared with other solutions (p < .001). Group IV (EDTA) had the highest integrity of muscle and collagen type I and III (P < 0.01). Demineralization with 10% acetic acid was the most effective at preserving bone tissue, while 5% EDTA was the best at maintaining collagen and adjacent muscle to bone. In conclusion, nitric acid at 5% showed the most efficient result as it balanced both time and cost as a demineralizing solution.


Assuntos
Técnica de Desmineralização Óssea/economia , Técnica de Desmineralização Óssea/métodos , Técnica de Descalcificação/economia , Técnica de Descalcificação/métodos , Fêmur/química , Estudos de Tempo e Movimento , Ácido Acético/química , Animais , Osso e Ossos/química , Colágeno Tipo I/análise , Colágeno Tipo III/análise , Ácido Edético/química , Formiatos/química , Masculino , Músculos/fisiologia , Ácido Nítrico/química , Ratos , Ratos Wistar , Coloração e Rotulagem/economia , Coloração e Rotulagem/métodos
13.
Food Chem Toxicol ; 95: 128-36, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27402098

RESUMO

To examine the human exposure to a novel silver and copper nanoparticle (AgNP and CuNP)/polystyrene-polyethylene oxide block copolymer (PS-b-PEO) food packaging coating, the migration of Ag and Cu into 3% acetic acid (3% HAc) food simulant was assessed at 60 °C for 10 days. Significantly lower migration was observed for Ag (0.46 mg/kg food) compared to Cu (0.82 mg/kg food) measured by inductively coupled plasma - atomic emission spectrometry (ICP-AES). In addition, no distinct population of AgNPs or CuNPs were observed in 3% HAc by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The predicted human exposure to Ag and Cu was used to calculate a margin of exposure (MOE) for ionic species of Ag and Cu, which indicated the safe use of the food packaging in a hypothetical scenario (e.g. as fruit juice packaging). While migration exceeded regulatory limits, the calculated MOE suggests current migration limits may be conservative for specific nano-packaging applications.


Assuntos
Ácido Acético/química , Anti-Infecciosos , Cobre/análise , Embalagem de Alimentos , Nanopartículas Metálicas/análise , Polímeros/química , Prata/análise , Cobre/química , Contaminação de Alimentos/análise , Análise de Perigos e Pontos Críticos de Controle , Humanos , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Nanotecnologia , Medição de Risco , Prata/química , Espectrofotometria Atômica
14.
Bioresour Technol ; 218: 491-7, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27394995

RESUMO

Carob pods are an inexpensive by-product of locust bean gum industry that can be used as renewable feedstock for bio-based succinic acid. Here, for the first time, unprocessed raw carob pods were used to extract a highly enriched sugar solution, afterwards used as substrate to produce succinic acid using Actinobacillus succinogenes. Batch fermentations containing 30g/L sugars resulted in a production rate of 1.67gSA/L.h and a yield of 0.39gSA/g sugars. Taking advantage of A. succinogenes' metabolism, uncoupling cell growth from succinic acid production, a fed-batch mode was implemented to increase succinic acid yield and reduce by-products formation. This strategy resulted in a succinic acid yield of 0.94gSA/g sugars, the highest yield reported in the literature for fed-batch and continuous experiments, while maintaining by-products at residual values. Results demonstrate that raw carob pods are a highly efficient feedstock for bio-based succinic acid production.


Assuntos
Actinobacillus/metabolismo , Carboidratos/química , Galactanos/química , Mananas/química , Gomas Vegetais/química , Ácido Succínico/química , Ácido Acético/química , Análise Custo-Benefício , Fabaceae/química , Fermentação , Tecnologia de Alimentos , Formiatos/química , Microbiologia Industrial , Cinética , Água/química
15.
Biotechnol Prog ; 32(4): 971-7, 2016 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-27390294

RESUMO

Mitigating the effect of fermentation inhibitors in bioethanol plants can have a great positive impact on the economy of this industry. Liquid-liquid extraction (LLE) using ethyl acetate is able to remove fermentation inhibitors-chiefly, acetic acid-from an aqueous solution used to produce bioethanol. The fermentation broth resulting from LLE has higher performance for ethanol yield and its production rate. Previous techno-economic analyses focused on second-generation biofuel production did not address the impact of removing the fermentation inhibitors on the economic performance of the biorefinery. A comprehensive analysis of applying a separation system to mitigate the fermentation inhibition effect and to provide an analysis on the economic impact of removal of acetic acid from corn stover hydrolysate on the overall revenue of the biorefinery is necessary. This study examines the pros and cons associated with implementing LLE column along with the solvent recovery system into a commercial scale bioethanol plant. Using details from the NREL-developed model of corn stover biorefinery, the capital costs associated with the equipment and the operating cost for the use of solvent were estimated and the results were compared with the profit gain due to higher ethanol production. Results indicate that the additional capital will add 1% to the total capital and manufacturing cost will increase by 5.9%. The benefit arises from the higher ethanol production rate and yield as a consequence of inhibitor extraction and results in a $0.35 per gallon reduction in the minimum ethanol selling price (MESP). © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:971-977, 2016.


Assuntos
Ácido Acético/isolamento & purificação , Extração Líquido-Líquido/economia , Ácido Acético/química , Ácido Acético/farmacologia , Biocombustíveis , Etanol/química , Etanol/metabolismo , Fermentação/efeitos dos fármacos , Zea mays/química , Zea mays/metabolismo
16.
J Sci Food Agric ; 96(11): 3795-800, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26676993

RESUMO

BACKGROUND: Fish skin has become a new source of collagen. It is usually extracted at low temperature. Increasing the extraction temperature can increase the collagen yield. However, high temperature might cause degradation of the triple helical structure of collagen, which is related to its functional biomaterial. This work thus aimed to investigate the effect of extraction temperature on the extraction efficiency and characteristics of acid-soluble collagen (ASC), particularly its triple helical structure. RESULTS: ASC was extracted at 5 ± 1, 15 ± 1 and 25 ± 1 °C for 0-24 h with 0.3 or 0.5 mol L(-1) acetic acid. The results showed that extraction with 0.5 mol L(-1) acetic acid gave a higher extraction efficiency than that in 0.3 mol L(-1) acetic acid (P < 0.5). Extraction at 25 ± 1 °C for 5 h with 0.5 mol L(-1) acetic acid gave a higher extraction efficiency (73.73 ± 1.28%), which is higher than that of 5 ± 1 °C by about 1.7-fold. All ASC obtained were identified as type I collagen and showed similar physicochemical properties. CONCLUSION: The results showed that extraction temperature strongly affected extraction efficiency. Extraction at 25 °C did not affect the triple helical structure, which was confirmed by the results of Fourier transform infrared, circular dichroism spectrum and collagen self-assembly. © 2015 Society of Chemical Industry.


Assuntos
Ciclídeos , Colágeno Tipo I/química , Proteínas de Peixes/química , Resíduos Industriais/análise , Pele/química , Ácido Acético/química , Animais , Dicroísmo Circular , Temperatura Baixa , Colágeno Tipo I/economia , Colágeno Tipo I/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Proteínas de Peixes/economia , Proteínas de Peixes/isolamento & purificação , Indústria de Processamento de Alimentos/economia , Hidroxiprolina/análise , Indicadores e Reagentes/química , Resíduos Industriais/economia , Cinética , Microscopia Eletrônica de Varredura , Desnaturação Proteica , Dobramento de Proteína , Estabilidade Proteica , Estrutura Secundária de Proteína , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Tailândia
17.
PLoS One ; 10(11): e0141969, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26569487

RESUMO

BACKGROUND: South Africa has high rates of HIV and HPV and high incidence and mortality from cervical cancer. However, cervical cancer is largely preventable when early screening and treatment are available. We estimate the costs and cost-effectiveness of conventional cytology (Pap), visual inspection with acetic acid (VIA) and HPV DNA testing for detecting cases of CIN2+ among HIV-infected women currently taking antiretroviral treatment at a public HIV clinic in Johannesburg, South Africa. METHODS: Method effectiveness was derived from a validation study completed at the clinic. Costs were estimated from the provider perspective using micro-costing between June 2013-April 2014. Capital costs were annualized using a discount rate of 3%. Two different service volume scenarios were considered. Threshold analysis was used to explore the potential for reducing the cost of HPV DNA testing. RESULTS: VIA was least costly in both scenarios. In the higher volume scenario, the average cost per procedure was US$ 3.67 for VIA, US$ 8.17 for Pap and US$ 54.34 for HPV DNA. Colposcopic biopsies cost on average US$ 67.71 per procedure. VIA was least sensitive but most cost-effective at US$ 17.05 per true CIN2+ case detected. The cost per case detected for Pap testing was US$ 130.63 using a conventional definition for positive results and US$ 187.52 using a more conservative definition. HPV DNA testing was US$ 320.09 per case detected. Colposcopic biopsy costs largely drove the total and per case costs. A 71% reduction in HPV DNA screening costs would make it competitive with the conservative Pap definition. CONCLUSIONS: Women need access to services which meet their needs and address the burden of cervical dysplasia and cancer in this region. Although most cost-effective, VIA may require more frequent screening due to low sensitivity, an important consideration for an HIV-positive population with increased risk for disease progression.


Assuntos
Análise Custo-Benefício , Detecção Precoce de Câncer/métodos , Infecções por HIV/complicações , Teste de Papanicolaou/economia , Infecções por Papillomavirus/diagnóstico , Neoplasias do Colo do Útero/diagnóstico , Ácido Acético/química , Adolescente , Adulto , Idoso , Coinfecção , Colposcopia/economia , DNA Viral/análise , Detecção Precoce de Câncer/economia , Reações Falso-Positivas , Feminino , Custos de Cuidados de Saúde , Humanos , Programas de Rastreamento/economia , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Papillomaviridae/genética , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/economia , África do Sul , Neoplasias do Colo do Útero/complicações , Neoplasias do Colo do Útero/economia , Esfregaço Vaginal , Estudos de Validação como Assunto , Adulto Jovem , Displasia do Colo do Útero/complicações , Displasia do Colo do Útero/diagnóstico , Displasia do Colo do Útero/economia
18.
PLoS One ; 10(6): e0130030, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26121588

RESUMO

A field study was conducted to compare the formationand bacterial communities of rhizosheaths of wheat grown under wheat-cotton and wheat-rice rotation and to study the effects of bacterial inoculation on plant growth. Inoculation of Azospirillum sp. WS-1 and Bacillus sp. T-34 to wheat plants increased root length, root and shoot dry weight and dry weight of rhizosheathsoil when compared to non-inoculated control plants, and under both crop rotations. Comparing both crop rotations, root length, root and shoot dry weight and dry weight of soil attached with roots were higher under wheat-cotton rotation. Organic acids (citric acid, malic acid, acetic acid and oxalic acid) were detected in rhizosheaths from both rotations, with malic acid being most abundant with 24.8±2 and 21.3±1.5 µg g(-1) dry soil in wheat-cotton and wheat-rice rotation, respectively. Two sugars (sucrose, glucose) were detected in wheat rhizosheath under both rotations, with highest concentrations of sucrose (4.08±0.5 µg g(-1) and 7.36±1.0 µg g(-1)) and glucose (3.12±0.5 µg g(-1) and 3.01± µg g(-1)) being detected in rhizosheaths of non-inoculated control plants under both rotations. Diversity of rhizosheath-associated bacteria was evaluated by cultivation, as well as by 454-pyrosequencing of PCR-tagged 16S rRNA gene amplicons. A total of 14 and 12 bacterial isolates predominantly belonging to the genera Arthrobacter, Azospirillum, Bacillus, Enterobacter and Pseudomonaswere obtained from the rhizosheath of wheat grown under wheat-cotton and wheat-rice rotation, respectively. Analysis of pyrosequencing data revealed Proteobacteria, Bacteriodetes and Verrucomicrobia as the most abundant phyla in wheat-rice rotation, whereas Actinobacteria, Firmicutes, Chloroflexi, Acidobacteria, Planctomycetes and Cyanobacteria were predominant in wheat-cotton rotation. From a total of 46,971 sequences, 10.9% showed ≥97% similarity with 16S rRNA genes of 32 genera previously shown to include isolates with plant growth promoting activity (nitrogen fixation, phosphate-solubilization, IAA production). Among these, the most predominant genera were Arthrobacter, Azoarcus, Azospirillum, Bacillus, Cyanobacterium, Paenibacillus, Pseudomonas and Rhizobium.


Assuntos
Azospirillum/genética , Bacillus/genética , Microbiologia do Solo , Triticum/crescimento & desenvolvimento , Triticum/microbiologia , Ácido Acético/química , Agricultura , Azospirillum/fisiologia , Bacillus/fisiologia , Biodiversidade , Ácido Cítrico/química , Produtos Agrícolas , Glucose/química , Gossypium , Malatos/química , Nitrogênio/química , Oryza , Ácido Oxálico/química , Fósforo/química , Filogenia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Análise de Componente Principal , RNA Ribossômico 16S/metabolismo , Sacarose/química
19.
Artigo em Inglês | MEDLINE | ID: mdl-25832559

RESUMO

A survey of 2-acetyl-4-tetrahydroxybutylimidazole (THI) and 4-methylimidazole (4-MeI) concentrations in caramel colours, vinegar and beverages from the Chinese market were performed by ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). In total, 117 samples, 78 caramel colour samples, 23 vinegar samples and 16 beverage samples, were investigated. The results indicated that 4-MeI was found in all samples. THI was found in a part of the samples and also the level range was lower compared to 4-MeI. In caramel colour samples, the concentration level range of THI was 1.0-74.3 mg/kg and of 4-MeI was 1.5-1291.8 mg/kg. In vinegar samples, the concentration level range of THI was 13.3-119.2 µg/L and for 4-MeI 111.2-2077.8 µg/L. In beverage samples, THI was only found in two samples and the concentration level range of 4-MeI was 10.8-307.1 µg/L. THI and 4-MeI levels in vinegar and beverages were rather low compared with those in caramel colour samples. These observations can be helpful for evaluating individual exposure to THI and 4-MeI from caramel colours, vinegar and beverages in China.


Assuntos
Bebidas/análise , Carboidratos/química , Carcinógenos/análise , Condimentos/análise , Contaminação de Alimentos , Imidazóis/análise , Ácido Acético/química , Ácido Acético/economia , Ácido Acético/normas , Bebidas/economia , Bebidas/normas , Carboidratos/normas , China , Cromatografia Líquida de Alta Pressão , Condimentos/economia , Condimentos/normas , Inspeção de Alimentos/métodos , Guias como Assunto , Limite de Detecção , Reação de Maillard , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
20.
Bioprocess Biosyst Eng ; 38(4): 691-700, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25332127

RESUMO

Volatile fatty acids (VFAs) that can be derived from food wastes were used for microbial lipid production by Chlorella protothecoides in heterotrophic cultures. The usage of VFAs as carbon sources for lipid accumulation was investigated in batch cultures. Culture medium, culture temperature, and nitrogen sources were explored for lipid production in the heterotrophic cultivation. The concentration and the ratio of VFAs exhibited significant influence on cell growth and lipid accumulation. The highest lipid yield coefficient and lipid content of C. protothecoides grown on VFAs were 0.187 g/g and 48.7%, respectively. The lipid content and fatty acids produced using VFAs as carbon sources were similar to those seen on growth and production using glucose. The techno-economic analysis indicates that the biodiesel derived from the lipids produced by heterotrophic C. protothecoides with VFAs as carbon sources is very promising and competitive with other biofuels and fossil fuels.


Assuntos
Carbono/química , Chlorella/metabolismo , Ácidos Graxos Voláteis/química , Lipídeos/biossíntese , Ácido Acético/química , Técnicas de Cultura Celular por Lotes , Biocombustíveis , Biomassa , Ácido Butírico/química , Meios de Cultura , Ácidos Graxos/química , Glucose/química , Processos Heterotróficos , Microbiologia Industrial , Nitrogênio/química , Propionatos/química
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