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1.
Water Sci Technol ; 80(3): 541-550, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31596265

RESUMO

Today, the development and testing of methods for fault detection and identification in wastewater treatment research relies on two important assumptions: (i) that sensor faults appear at distinct times in different sensors and (ii) that any given sensor will function near-perfectly for a significant amount of time following installation. In this work, we show that such assumptions are unrealistic, at least for sensors built around an ion-selective measurement principle. Indeed, long-term exposure of sensors to treated wastewater shows that sensors exhibit fault symptoms that appear simultaneously and with similar intensity. Consequently, this suggests that future research should be reoriented towards methods that do not rely on the assumptions mentioned above. This study also provides the first empirically validated sensor fault model for wastewater treatment simulation, which is useful for effective benchmarking of both fault detection and identification methods and advanced control strategies. Finally, we evaluate the value of redundancy for remote sensor validation in decentralized wastewater treatment systems.


Assuntos
Monitoramento Ambiental/instrumentação , Águas Residuárias , Concentração de Íons de Hidrogênio
2.
Ying Yong Sheng Tai Xue Bao ; 30(9): 3215-3223, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31529897

RESUMO

The modified fly ash (MFA) was prepared through roasting the mixture of fly ash and NaOH/Ca(OH)2 at 250 ℃ for 1.5 h. The physicochemical properties of MFA were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), surface area analyze (BET), and Fourier transform infrared spectroscopy (FTIR) techniques. Results from BET analysis showed that the BET of MFA was enlarged by 20.6 times compared with FA. Results from SEM analysis showed that the glass phase was dissolved, with a rough surface and porous structure. Results from FTIR analysis demonstrated that -OH played an important role in Cd2+ adsorption. Results from the static adsorption experiment revealed that the removal efficiency of Cd2+ reached 97.3% when 0.2 g MFA was applied while the concentration of Cd2+ was 100 mg·L-1, the solution pH was 7.0, the adsorption temperature was 25 ℃ and the adsorption time was 90 min. In addition, the coexisting cations (K+, Na+, Mg2+, and Ca2+) might inhibit Cd2+ adsorption. Among all the cations, Ca2+ showed a most significant inhibitory effect on the removal of Cd2+. Langmuir isotherm and the pseudo-second-order kinetic models could well describe the adsorption behavior of Cd2+ on MFA, with the maximum adsorption capacity of 55.77 mg·g-1. Meanwhile, thermodynamic studies showed that Cd2+ adsorption onto MFA was spontaneous and endothermic process. MFA had better adsorption capacity than FA and had certain application pro-spects in wastewater treatment.


Assuntos
Cádmio/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Poluentes Químicos da Água/química , Adsorção , Cinza de Carvão , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
3.
Sheng Wu Gong Cheng Xue Bao ; 35(9): 1787-1796, 2019 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-31559759

RESUMO

Chitinase has a wide industrial application prospect. For example, it can degrade shrimp shells, crab shells and other crustacean waste into high value-added chitooligosaccharides. However, the low catalytic efficiency of chitinase greatly limits the production of chitooligosaccharides. In previous study, the we expressed a chitinase Chisb with high catalytic efficiency and studied its enzymatic properties. In order to further improve the catalytic efficiency of Chisb, with R13NprB-C-SP-H as the parent, here error-prone PCR was used to construct random mutant library to conduct directed evolution of chitinase Chisb. Two mutants C43D and E336R were obtained with 96-well plate primary screening and shaker-screening, and their enzymatic properties were also studied. The optimum temperature of C43D and E336R was 55 °C, and the optimum pH of C43D was 5.0, while that of E336R was 9.0. The catalytic efficiency of C43D and E336R was 1.35 times and 1.57 times higher than that of control. The chitooligosaccharide concentration of E336R and C43D was 2.53 g/L and 2.06 g/L, improved by 2.84 times and 2.31 times compared with the control (0.89 g/L), respectively. In addition, the substrate conversion rate of mutants E336R and C43D was 84.3% and 68.7%, improved by 54.6% and 39% compared with the control (29.7%), respectively. In summary, the study indicates that random mutation introduced by error-prone PCR can effectively improve the catalytic efficiency of chitinase Chisb. The positive mutants with higher catalytic efficiency obtained in the above study and their enzymatic property analysis have important research significance and application value for the biosynthesis of chitooligosaccharides.


Assuntos
Biocatálise , Quitina/análogos & derivados , Quitinases , Concentração de Íons de Hidrogênio , Reação em Cadeia da Polimerase
4.
Pharm Res ; 36(11): 155, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31485804

RESUMO

PURPOSE: The purpose of this study was to determine the impact of food on gastric pH and the ability of over the counter betaine hydrochloride (BHCl) acid to reacidify gastric pH after food-induced elevations in gastric pH. METHODS: This open-label cross over clinical study (NCT02758015) included 9 subjects who were randomly assigned to one of 16 possible, 4-period cross-over sequences to determine the impact and relationship of food and gastric pH with acid supplementation. Subjects were administered various doses (1500 mg, 3000 mg and 4500 mg) of betaine hydrochloride (BHCl) to determine the ability of acid supplementation to reacidify gastric pH after the elevation of gastric pH caused by the ingestion of food. RESULTS: Following the administration of food and the resulting elevation in gastric pH, time to return to baseline gastric pH levels without acid supplementation was 49.7 ± 14.0 min. Administering 4500 mg of BHCl acid in capsules was able to reacidify gastric pH levels back to baseline following the administration of food in approximately 17.3 ± 5.9 min. AUCpH of each treatment were similar and not statistically different. Mean max pH following the administration of food was 3.20 ± 0.55. CONCLUSION: The ability of food to elevate and maintain gastric pH levels in the presence of acid supplementation was made evident throughout the study. A 4500 mg dose of BHCl was required to reacidify gastric pH after the administration of food. This study details the difficulty faced by clinicians in dosing a poorly soluble, weakly basic drug to patients receiving acid reducing agents where administration with food is recommended to avoid gastric side effects. TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT02758015.


Assuntos
Betaína/uso terapêutico , Alimentos , Absorção Gástrica , Ácido Gástrico/metabolismo , Fármacos Gastrointestinais/uso terapêutico , Preparações Farmacêuticas/metabolismo , Administração Oral , Adolescente , Adulto , Estudos Cross-Over , Feminino , Interações Alimento-Droga , Determinação da Acidez Gástrica , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
5.
Water Sci Technol ; 80(2): 300-307, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31537766

RESUMO

The aim of this work is to study the performances of isomeric α-, ß-, and γ-FeOOH (goethite, akaganéite and lepidocrocite, including five samples named as Gth1 and Gth2, Aka1 and Aka2, and Lep, respectively) for removing hexavalent chromium (Cr(VI)) from aqueous solutions. The adsorption mechanisms were explored by kinetic and isothermal experiments. Adsorption efficiencies under the different pH values, anions, and the levels of adsorbate and adsorbent were also measured. Results showed that the Cr(VI) adsorption by isomeric FeOOH could be best described by pseudo-second-order kinetic model. The processes of Cr(VI) isothermal adsorption could be greatly fitted by the Langmuir and Freundlich equations with the high correlation coefficients of R2 (>0.92). Also, there were the optimum pH values of 3.0-8.0 for FeOOH to adsorb Cr(VI), and their adsorption capacities were tightly related with the active sites of adsorbents. Cr(VI) adsorptions by these adsorbents were easily influenced by H2PO4-, and then SO42-, while there were little effects by Cl-, CO32- and NO3-. These obtained results could provide a potentially theoretical evidence for isomeric FeOOH materials applied in the engineering treatment of the polluted chromate-rich waters.


Assuntos
Cromo/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análise
6.
Water Sci Technol ; 80(2): 308-316, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31537767

RESUMO

In this study, a novel composite of modified diatomite supported nanoscale zero-valent iron (mD-NZVI) was synthesized and characterized. The effects of four factors (mD-NZVI dose, temperature, contact time and initial pH) on the removal of Cr(VI) by mD-NZVI were studied by experimental work and analyzed by response surface methodology (RSM). A second-order polynomial equation fitted by Box-Behnken design was used as a statistical model and proved to be precise in describing the significance of four factors. The analysis results show that the effects of four factors on the removal efficiency of Cr(VI) were significant (F value is 19.83), initial pH was found to be the key factor. In addition, the effect of initial pH was further studied and the maximum removal efficiency of 89.34% was obtained at pH of 3, the decrease in removal efficiency with the increase in pH is a synergistic effect of Cr(VI) species, surface charge of mD-NZVI and OH- amount at different pH.


Assuntos
Cromo/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Cromo/análise , Terra de Diatomáceas , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise
7.
Bioresour Technol ; 293: 122071, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491651

RESUMO

Chitosan-ethylene glycol diglycidyl ether/TiO2 nanoparticles (CS-EGDE/TNP) composite was synthesized to be biosorbent for the removal of reactive orange 16 (RO16) dye from aqueous solution. The CS-EGDE/TNP composite was characterized via BET, XRD, FTIR, and SEM-EDX techniques. Response surface methodology (RSM) with Box-Behnken design (BBD) was applied to optimize the adsorption key parameters such as adsorbent dose (A: 0.02-0.08 g/L), RO16 dye concentration (B: 20-80 mg/L), solution pH (C: 4-10), temperature (D: 30-50 °C), and contact time (E: 30-90 min). The adsorption isotherm followed Freundlich model and pseudo-second order (PSO) kinetic model. The adsorption capacity of CS-EGDE/TNP for RO16 dye was 1407.4 mg/g at 40 °C. The adsorption mechanism of RO16 dye on the surface of CS-EGDE/TNP can be attributed to various interactions such as electrostatic attraction, n-π interaction, Yoshida H-bonding, and H-bonding. Results supported the potential use of CS-EGDE/TNP as effective adsorbent for the treatment of acid reactive dye.


Assuntos
Quitosana , Nanopartículas , Adsorção , Compostos Azo , Resinas Epóxi , Concentração de Íons de Hidrogênio , Cinética
8.
Bioresour Technol ; 293: 122074, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491652

RESUMO

Effect of pH on waste activated sludge (WAS) hydrolysis and decomposition treating with lysozyme and rhamnolipid combined (Ly + RL) was investigated in this study. Results showed that Ly + RL system could significantly improve the release of soluble organic matters at the optimal RL dosage of 0.3 g/gSS and lysozyme dosage of 0.15 g/gSS. Alkali conditions showed better effect than that of acid on the release of soluble organics, improvement of WAS biodegradability and reduction of big floc size within Ly + RL treatment system and the optimal pH was 10. And 9591.6 mg/L soluble chemical oxygen demand (SCOD), 1612.0 mg/L protein and 1211.6 mg/L polysaccharide were released at pH10 after 12 h co-digestion. 83.7% bacteria and 92.2% archaea were decomposed at pH10. Class Gammaproteobacteria (82.4%) was the predominant bacteria after treated by Ly + RL system, and the treated WAS was beneficial for the subsequent organics bio-degradation and volatile fatty acids accumulation.


Assuntos
Muramidase , Esgotos , Glicolipídeos , Concentração de Íons de Hidrogênio , Hidrólise , Eliminação de Resíduos Líquidos
9.
Bioresour Technol ; 293: 122088, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31499331

RESUMO

This study presented an innovative method for phosphorus (P) recovery as vivianite from waste activated sludge (WAS) via optimizing iron dosing and pH value during anaerobic fermentation (AF). The optimal conditions for vivianite formation were in the pH range of 6.0-9.0 with initial PO43- >5 mg/L and Fe/P molar ratio of 1.5. Notably, FeCl3 showed advantages over ZVI for the simultaneous release of Fe2+ and PO43- during WAS fermentation, especially in acidic conditions. The FeCl3 dosing at pH 3.0 could contribute to 78.81% Fe2+ release and 85.69% of total PO43- release from WAS. They were ultimately recovered in the form of high-purity vivianite (93.67%). Clostridiaceae (40.25%) was the predominant bacteria in FeCl3-pH3 reactors, which played key roles in inducing dissimilatory iron reduction for Fe2+ formation. Therefore, P recovery as vivianite from WAS fermentation might be a promising and highly valuable approach to relieve the P crisis.


Assuntos
Fósforo , Esgotos , Anaerobiose , Fermentação , Compostos Ferrosos , Concentração de Íons de Hidrogênio , Ferro , Fosfatos , Eliminação de Resíduos Líquidos
10.
Bioresour Technol ; 293: 122056, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31514117

RESUMO

Aiming at optimizing the adsorption process of Chlorella vulgaris and cationic starch, the adsorption thermodynamic characteristics were evaluated. Different from inorganic calcium salt adsorbent, the adsorption nature of organic polymer cationic starch is exothermic (ΔH°â€¯< 0) and spontaneous (ΔG°â€¯< 0). Besides, the adsorption capacity and rate can be well described by Langmiur isotherm and pseudo second kinetic models. As results of exothermic nature and great driving force of lower temperature, the adsorption capacity and rate declined with the rising temperature. The maximal values of them were obtained at 278.15 K, which were 9148.14 mg microalgae (g cationic starch)-1 and 8.74 × 10-6 mg g-1 min-1. Additionally, with insufficient adsorbent, the highest adsorption efficiency (96.37%) was achieved at 278.15 K for stirring 150 min. For 288.15, 298.15, 308.15 and 318.15 K, the adsorption efficiency decreased to 93.77%, 86.75%, 83.32% and 81.57% and the time consumed were at least 40 min longer.


Assuntos
Chlorella vulgaris , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Polímeros , Amido , Temperatura Ambiente , Termodinâmica
11.
Bioresour Technol ; 293: 122098, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31514118

RESUMO

As a stable microbial polysaccharide, scleroglucan has extensive application in the food, medicine, and cosmetics industries. However, its large-scale industrial application is limited by its high production cost, low yield, long production time, etc. This study aims to enhance scleroglucan production by Sclerotium rolfsii WSH-G01. Based on the analysis of batch fermentation kinetics parameters, a pH-shift strategy was adopted. Through systematic kinetics analysis, a 32.4 g/L scleroglucan was accomplished. The kinetic model of the pH-shift batch fermentation process was established using a logistic equation, Luedeking-Piret equation, and a Luedeking-Piret-like equation. As decreased glucose concentration could cause decreased scleroglucan synthesis rates during the batch fermentation process, 30 g/L glucose was fed in the later phase of fermentation. As a result, scleroglucan production increased to 42 g/L, with a productivity of 0.5 g/L·h. Thus, the pH-shift strategy and feeding approach could be useful for industrial scleroglucan production.


Assuntos
Basidiomycota , Glucanos , Fermentação , Concentração de Íons de Hidrogênio , Cinética
12.
Bioresour Technol ; 293: 122093, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31518818

RESUMO

The endocarp of Wodyetia bifurcata was used to produce biochar by vacuum pyrolysis as an alternative adsorbent for methylene blue (MB) removal. The influence of different pyrolysis temperatures, particle diameters and activation agents in the adsorption process was studied. Kinetics and adsorption equilibrium were also evaluated. Biochar obtained at higher pyrolysis temperatures and activated with H3PO4 showed the best adsorptive capacities, achieving 83% of MB removal. The experimental data fitted better with pseudo-second order model. Isotherms performed at 25, 40, 50 and 60 °C showed that the adsorption of MB onto the activated biochar had no concentration dependence in the range studied. Experimental isotherms fitted well with the Freundlich and Sips models and the thermodynamic parameters suggested a physical adsorption mechanism in a heterogeneous surface, spontaneous at all temperatures evaluated. In brief, the activated carbon obtained from Wodyetia bifurcata can be a promising material for MB removal from aqueous solutions.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Azul de Metileno
13.
Waste Manag ; 99: 49-59, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31472440

RESUMO

Hydrothermal liquefaction (HTL) of Animal By-Products (ABP) is a promising technology for their recycling and disposal. Different operating parameters have been studied to determine their influence on the process. Higher heating values of biocrudes ranging between 35 and 39 MJ/kg have been obtained showing a maximum yield of 61% at 225 °C. At low HTL temperature, the products are similar to those of rendering process and the biocrude is mainly formed by triglycerides and fatty acids in a 90:10 ratio, approximately. By increasing temperature, the free fatty acid yield increases, as well as amides and heterocyclic compounds as a result of the triglycerides and protein reactions. Between 250 and 290 °C a great difference in the composition of the biocrude obtained is observed. Water content also showed significant effects on the product yields. Large amounts of foams were obtained at low water contents that were minimised when it is increased. This is a very important feature to be considered for scaling up the phase separation process. Glycerine amount in the aqueous phase was remarkable, as a consequence of fat hydrolysis. Increasing pH to 9 increases the extraction of organics into the aqueous phase, whereas operating at pH 5 yields similar amounts of biocrude as compared with neutral pH, with a higher percentage of fatty acids. Reusing of the aqueous phase is necessary for the viability of the process and leads to increasing amounts of dissolved organics in the aqueous phase with the number of cycles, reaching a saturation level after three-four recycling rounds.


Assuntos
Microalgas , Animais , Biocombustíveis , Concentração de Íons de Hidrogênio , Temperatura Ambiente , Água
14.
Phys Chem Chem Phys ; 21(37): 20750-20756, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31513191

RESUMO

"Intelligent" materials based on synthetic small molecules that become functional only under specific conditions provide new opportunities for developing regulated systems aimed at a large number of applications. For instance, biologically active supramolecular entities that are sensitive to environmental conditions, such as the presence of bacterial membranes, are extremely interesting in biomedicine. In this work, we have designed and investigated, using molecular dynamics simulations, a doubly modulable nanotube formed by the self-assembly of cyclic peptides sensitive to both the presence of a lipid membrane and the pH of the aqueous media. The cyclic peptides were designed to self-assemble into peptide nanotubes in the presence of a lipid bilayer and at low pH values. Under these conditions, the residual side chains point outside the cyclic peptides, being exposed to the lipid bilayer, and the inner groups (carboxylic acids) are protonated, thus allowing the permeation of water and preventing that of ions. Higher pH values are expected to create carboxylate groups at the lumen of the peptides, leading to the disassembly of the nanotube, the attraction and translocation of ions towards the hydrophobic core of the bilayer, and eventually killing the target malignant cells. Our results suggest that by introducing a second switch in a membrane sensitive system, it is possible to modulate its interaction with the lipid bilayer. This opens the door to new strategies for the preparation of antimicrobial peptides that interact at the membrane level.


Assuntos
Nanotubos de Peptídeos/química , Peptídeos Cíclicos/química , Anti-Infecciosos/química , Bactérias/química , Concentração de Íons de Hidrogênio , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular
15.
J Appl Oral Sci ; 27: e20180593, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31508792

RESUMO

There is growing evidence that C. albicans is associated with dental caries, but its role on caries development needs to be better clarified. Label="OBJECTIVE">To evaluate at the hard tissue level the effect of C. albicans on the cariogenic potential of S. mutans biofilms focusing on the mineral profile of induced carious lesions. This study also aimed to evaluate the effect of C. albicans on the acidogenic potential of S. mutans biofilms. METHODOLOGY Dual-species (CA+SM) and single-species biofilms (CA or SM) were grown on the surface of enamel slabs in the presence of glucose/sucrose supplemented culture medium for 24, 48 and 72 hours. Demineralization was evaluated through percentage of surface microhardness change (%SMC) and transversal microradiography analysis (ILM and LD) and pH of the spent medium was recorded daily. Data were analyzed by two-way ANOVA followed by Bonferroni correction. RESULTS%SMC was statistically different among the biofilms at each time point being the highest for SM biofilms and the lowest for CA biofilms which also differed from CA+SM biofilms [SM (24 h: 47.0±7.3; 48 h: 66.3±8.3; 72 h: 75.4±3.9); CA (24 h: 7.3±3.3; 48 h: 7.1±6.4; 72 h: 6.6±3.6); CA+SM (24 h: 35.9±7.39.1; 48 h: 47.2±9.5; 72 h: 47.6±9.5)]. pH of spent medium was statistically lower for SM biofilms compared to the other biofilms at each time point and remained constant over time while pH values increased from 24 to 72 h for both CA and CA+SM biofilms [SM (24 h: 4.4±0.1; 48 h: 4.4±0.1; 72 h: 4.5±0.1); CA (24 h: 6.9±0.3; 48 h: 7.2±0.2; 72 h: 7.5±0.2); CA+MS (24 h: 4.7±0.2; 48 h: 5.1±0.1; 72 h: 6.1±0.6)]. IML and LD for SM biofilms increased over time while no difference was observed from 24 to 72 h for the other biofilms. CONCLUSIONS The present data suggest that C. albicans has low enamel demineralization potential and the presence of C. albicans can reduce both the cariogenic and acidogenic potentials of S. mutans biofilms.


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Esmalte Dentário/microbiologia , Streptococcus mutans/metabolismo , Desmineralização do Dente/microbiologia , Ácidos/metabolismo , Animais , Bovinos , Contagem de Colônia Microbiana , Esmalte Dentário/química , Testes de Dureza , Concentração de Íons de Hidrogênio , Microrradiografia/métodos , Valores de Referência , Propriedades de Superfície , Fatores de Tempo
16.
Int J Nanomedicine ; 14: 4895-4909, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31456636

RESUMO

Introduction: Insulin is given by injection, because when administered orally, it would be destroyed by enzymes in the digestive system, hence only about 0.1% reaches blood circulation. The purpose of the present study was to use pH sensitive polyelectrolyte methyl methacrylate (MMA)/itaconic acid (IA) nanogels as carriers in an attempt to improve absorption of insulin administered orally. Methods: Insulin (Ins) was incorporated into the MMA/IA nanogels (NGs) using the polyelectrolyte complexation (PEC) method to form Ins/NGs-PEC. Several parameters, including Ins:NGs ratio, pH, incubation time and stirring rate were optimized during preparation of InsNGs-PEC. The prepared formulations were characterized in terms of particle size (PS), polydispersity index (PdI), zeta potential (ZP) and percent entrapment efficiency (% EE). Results: The optimized InF12 nanogels had a PS, PdI, ZP and %EE of 190.43 nm, 0.186, -16.70 mV and 85.20%, respectively. The InF12 nanogels were lyophilized in the presence of different concentrations of trehalose as cryoprotectant. The lyophilized InF12 containing 2%w/v trahalose (InF12-Tre2 nanogels) was chosen as final formulation which had a PS, PdI, ZP and %EE of 430.50 nm, 0.588, -16.50 mv and 82.10, respectively. The in vitro release of insulin from InF12-Tre2 nanogels in the SGF and SIF were 28.71% and 96.53%, respectively. The stability study conducted at 5±3°C for 3 months showed that lnF12-Tre2 nanogels were stable. The SDS-PAGE assay indicated that the primary structure of insulin in the lnF12-Tre2 nanogels was intact. The in-vivo study in the diabetic rats following oral administration of InF12-Tre2 nanogels at a dose of 100 IU/kg body weight reduced blood glucose level significantly to 51.10% after 6 hours compared to the control groups. Conclusions: The pH sensitive MMA/IA nanogels are potential carriers for oral delivery of insulin as they enhanced the absorption of the drug.


Assuntos
Liofilização , Insulina/administração & dosagem , Polieletrólitos/química , Polietilenoglicóis/administração & dosagem , Polietilenoimina/administração & dosagem , Administração Oral , Animais , Crioprotetores/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Masculino , Ratos Sprague-Dawley , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Fatores de Tempo
17.
Pestic Biochem Physiol ; 159: 22-26, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31400780

RESUMO

Herbicide efficacy depends on herbicides crossing cell and organelle membranes. We evaluated an artificial membrane system to understand how herbicides cross biological membranes. This understanding aids in predicting herbicide behavior in planta and, consequently, efficacy, mode of action, and whether active transporter-based herbicide resistance mechanisms may be possible. Five herbicides with different log Kow and pKa values were assessed: glyphosate, 2,4-D, clopyralid, sulfentrazone and glufosinate. The artificial membrane apparatus included four semipermeable membranes containing buffers with pH 2.7, 5 and/or 7.4, floating in a bath of diethyl ether. These conditions were based on the pH from different cellular compartments and the pKa for these herbicides. Changes in herbicide concentration due to movement were measured using radioactivity or liquid chromatography mass spectrometry. In general, herbicide behavior followed the pattern predicted by their calculated pKa and log Kow. Herbicides added to an acidic phase (pH 2.7) were more mobile than when they were added to the more basic phase (pH 7.4), except when herbicide's pKa was lower than the pH of the starting phase. Clopyralid, 2,4-D, and sulfentrazone showed significant acid trapping behavior due to their weak acid functional groups. Sulfentrazone and 2,4-D had a high affinity for the nonpolar, diethyl ether bath, especially when they were protonated at low pH. Our findings illustrate the robustness of the system to provide predictions about herbicide behavior at the subcellular level.


Assuntos
Herbicidas/metabolismo , Ácido 2,4-Diclorofenoxiacético/metabolismo , Aminobutiratos/metabolismo , Glicina/análogos & derivados , Glicina/metabolismo , Concentração de Íons de Hidrogênio , Membranas Artificiais , Ácidos Picolínicos/metabolismo , Sulfonamidas/metabolismo , Triazóis/metabolismo
18.
J Forensic Leg Med ; 67: 37-48, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31419763

RESUMO

Previous studies have begun to characterize the microbial community dynamics of the skin, soil, gut, and oral cavities of decomposing remains. One area that has yet to be explored in great detail is the microbiome of the fly larval mass, the community of immature flies that plays a significant role in decomposition. The current study aimed to characterize the microbiology and chemistry of larval masses established on pig (Sus scrofa domesticus) carcasses and to determine if these characteristics have potential as temporal evidence. Carcasses (n = 3) were decomposed on the soil surface of a tropical habitat on Oahu, Hawaii, USA and sampled over three days at 74 h, 80 h, 98 h, 104 h, 122 h, and 128 h (∼85-142 Accumulated Degree Days) postmortem. Larval masses were analyzed via high-throughput 16S rRNA sequencing and in situ chemical measurements (pH, temperature, oxidation-reduction potential). A trend was observed that resulted in three distinct microbial communities (pre-98 h, 98 h, and post-98 h). The oxidation-reduction potential (Eh) of larval masses apparently regulated microbial community structure with the most negative Eh being associated with the least rich and diverse microbial communities. Overall, a significant interaction between time and taxa was observed, particularly with bacterial phyla Firmicutes and Proteobacteria. The current results provide new insight into the microbial community and chemical parameters of larval masses and indicate a temporal shift that could be further studied as a PMI estimator.


Assuntos
Comportamento Alimentar , Larva/química , Larva/microbiologia , Microbiota , Mudanças Depois da Morte , Animais , Bactérias/genética , Entomologia , Patologia Legal , Hawaii , Concentração de Íons de Hidrogênio , Modelos Animais , Oxirredução , RNA Ribossômico 16S , Análise de Sequência de RNA , Suínos
19.
Pharm Res ; 36(10): 140, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31367876

RESUMO

PURPOSE: In order to overcome the obstacles and side effects of classical chemotherapy, numerous studies have been performed to develop the treatment based on targeted transport of active compounds directly to the site of action. Since tumor cells are featured with intensified glucose metabolism, we set out to develop innovative, glucose-modified PAMAM dendrimer for the delivery of doxorubicin to breast cancer cells. METHODS: PAMAM-dox-glc conjugate was synthesized and characterized by 1H NMR, FT-IR, size and zeta potential measurements. The drug release rate from conjugate was evaluated by dialysis under different pH conditions. The expression level of GLUT family receptors in cells cultured in full and glucose-deprived medium was evaluated by quantitative real-time RT-PCR and flow cytometry. The cytotoxicity of conjugate in presence or absence of GLUT1 inhibitors was determined by MTT assay. RESULTS: We showed that PAMAM-dox-glc conjugate exhibits pH-dependent drug release and increased cytotoxic activity compared to free drug in cells cultured in medium without glucose. Further, we proved that these cells overexpress transporters of GLUT family. The toxic effect of conjugate was eliminated by the application of specific GLUT1 inhibitors. CONCLUSION: Our findings revealed that the glucose moiety plays a crucial role in the recognition of cells with high expression of GLUT receptors. By selectively blocking GLUT1 transporter we showed its importance for the cytotoxic activity of PAMAM-dox-glc conjugate. These results suggest that PAMAM-glucose formulations may constitute an efficient platform for the specific delivery of anticancer drugs to tumor cells overexpressing transporters of GLUT family.


Assuntos
Antineoplásicos/farmacologia , Dendrímeros/química , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Transportador de Glucose Tipo 1/metabolismo , Glucose/efeitos adversos , Antineoplásicos/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Liberação Controlada de Fármacos , Regulação da Expressão Gênica , Glucose/química , Humanos , Concentração de Íons de Hidrogênio , Células MCF-7 , Tamanho da Partícula
20.
World J Microbiol Biotechnol ; 35(9): 136, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432249

RESUMO

Volatile phenols such as 4-ethylphenol are produced from hydroxycinnamic acids by Dekkera bruxellensis, an important yeast contaminating alcoholic fermentations. 4-ethylphenol results from the decarboxylation and reduction of p-coumaric acid, a compound found in sugarcane musts. In wine, volatile phenols are responsible by sensorial alterations whereas in the context of bioethanol fermentation, little is known about their effects on the main yeast, Saccharomyces cerevisiae. Here we evaluated the interaction of 4-ethylphenol and pH, sucrose and ethanol on the growth and fermentation capacity of the industrial strain of S. cerevisiae PE-2. A central compound rotational design was utilized to evaluate the effect of 4-ethylphenol, pH, ethanol and sucrose concentration on the yeast maximum specific growth rate (µmax) in microplate experiments in YPS medium (Yeast extract-Peptone-Sucrose), at 30 °C. Following, single-cycle fermentations in YPS medium, pH 4.5, 17% sucrose, at 30 °C, with 4-ethylphenol in concentrations of 10 and 20 mg L-1 being added at the start or after 4 h of fermentation, were carried out. 4-ethylphenol affected µmax of S. cerevisiae in situations that resemble the conditions of industrial bioethanol production, especially the low pH of the fermentation medium and the high ethanol concentration because of the anaerobic sucrose uptake. The addition of 4-ethylphenol on fermentation resulted in significant effect on the cell yeast concentration, pH and alcohol production, with significant decrease from 86% to the range of 65-74% in the fermentative efficiency. The industrial yeast S. cerevisiae PE-2 growth and fermentative capacity were affected by the presence of 4-ethylphenol, a metabolite produced by D. bruxellensis, which may contribute to explain the impact of this yeast on bioethanol industrial production.


Assuntos
Etanol/metabolismo , Fermentação , Microbiologia Industrial , Fenóis/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Sacarose/metabolismo , Meios de Cultura/química , Inibidores do Crescimento/metabolismo , Concentração de Íons de Hidrogênio , Saccharomyces cerevisiae/efeitos dos fármacos , Temperatura Ambiente
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