•Quinoa starch was used for development of biofilms.•Gold nanoparticles (AuNPs) were added to biofilms.•Effects of the addition of AuNPs about characteristics of biofilms quinoa starch.
Active ...biofilms of quinoa (Chenopodium quinoa, W.) starch were prepared by incorporating gold nanoparticles stabilised by an ionic silsesquioxane that contains the 1,4-diazoniabicyclo2.2.2octane chloride group. The biofilms were characterised and their antimicrobial activity was evaluated against Escherichiacoli and Staphylococcusaureus. The presence of gold nanoparticles produces an improvement in the mechanical, optical and morphological properties, maintaining the thermal and barrier properties unchanged when compared to the standard biofilm. The active biofilms exhibited strong antibacterial activity against food-borne pathogens with inhibition percentages of 99% against E. coli and 98% against S. aureus. These quinoa starch biofilms containing gold nanoparticles are very promising to be used as active food packaging for the maintenance of food safety and extension of the shelf life of packaged foods.
The effect of the support size on the properties of enzyme immobilization was investigated by using chitosan macroparticles and nanoparticles. They were prepared by precipitation and ionotropic ...gelation, respectively, and were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), light scattering analysis (LSA), and N2 adsorption–desorption isotherms. β-Galactosidase was used as a model enzyme. It was found that the different sizes and porosities of the particles modify the enzymatic load, activity, and thermal stability of the immobilized biocatalysts. The highest activity was shown by the enzyme immobilized on nanoparticles when 204.2 mg protein·(g dry support)−1 were attached. On the other hand, the same biocatalysts presented lower thermal stability than macroparticles. β-Galactosidase immobilized on chitosan macro and nanoparticles exhibited excellent operational stability at 37 °C, because it was still able to hydrolyze 83.2 and 75.93% of lactose, respectively, after 50 cycles of reuse.
Obesity and diabetes mellitus (DM) are public health concerns in Mexico of top-level priority due to their high prevalence and their growth rate in recent decades. The accumulation of adipose tissue ...leads to an unbalanced release of pro-oxidant factors, which causes cellular damage and favors the development of comorbidities. Recent evidence suggests that oxidative stress also promotes the accumulation of adipose tissue and the development of insulin resistance. The objective of this study is to evaluate the association between usual intake of antioxidant nutrients, specifically vitamins A, C, E and magnesium with body mass index (BMI), waist circumference (WC) and serum glucose concentrations in a representative sample of Mexican adults.
We analyzed data on diet, BMI, WC and serum glucose from the Mexican National Health and Nutrition Survey 2012. Analysis included 20- to 65-year-old adults without a known diagnosis of DM (n = 1573). Dietary information was obtained using the five-step multiple-pass method developed by the United States Department of Agriculture and adapted to the Mexican context. Nutrient usual intake distributions were estimated using the Iowa State University method, through the "Software for Intake Distribution Estimation" (PC-Side) v.1.02. Associations were analyzed using multivariate regression models.
Higher dietary magnesium intake was associated with lower markers of adiposity, so that an increase in 10 mg per 1000 kcal/day of magnesium was associated with an average decrease in BMI of 0.72% (95% CI: -1.36, - 0.08) and 0.49 cm (95% CI: -0.92, - 0.07) of WC. Additionally, in women with normal glucose concentrations, an increase in magnesium intake was associated with an average decrease in serum glucose by 0.59% (95% CI: -1.08, - 0.09).
The results suggest that magnesium intake is associated with lower BMI, WC and serum glucose in Mexican population. However, more studies are required to elucidate the nature of this association.
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► Ionic silica containing the pyridinium group was employed for the adsorption of RR-194 dye. ► Three samples were prepared varying the molar inorganic percentage. ► The materials ...were characterized by spectroscopic and thermogravimetric analyses. ► The higher surface area of the hybrid material leads to higher % of dye removal. ► Simulated dye-house effluent was treated with hybrid adsorbent materials.
The present study reports the development of an ionic silica based hybrid material containing the cationic pyridinium group, which was employed for the removal of the Reactive Red 194 textile dye from aqueous solution. Three hybrid material samples were prepared with planned textural and chemical properties, varying the inorganic precursor molar percentage in the sol–gel synthesis. The obtained samples were defined as Py/Si-90, Py/Si-92 and Py/Si-94, where the number specifies the inorganic molar percentage. The hybrid samples were characterized by elemental, infrared, 13C and 29Si NMR, N2 adsorption-desorption isotherms and thermogravimetric analyses. The dye-removing ability of these adsorbents was determined by the batch contact adsorption procedure. Effects such as pH value and adsorbent dosage on the adsorption capacities were studied. Four kinetic models were applied. The adsorption was best fitted to Avrami fractional-order kinetic model for the three hybrid material samples. The kinetic data were also adjusted to an intra-particle diffusion model resulting three linear regions, indicating that the adsorption kinetics follows multiple sorption rates. The equilibrium data were fitted to Langmuir, Freundlich and Liu isotherm models. The maximum adsorption capacities were 165.4, 190.3 and 195.9mgg−1 for Py/Si-90, Py/Si-92 and Py/Si-94, respectively. Simulated dye-house effluents were used to check the applicability of the proposed adsorbents for effluent treatment. Dye loaded adsorbents were regenerated (>98.2%) by using 0.4molL−1 of NaOH solution as an eluent.
•The improvement of food bioprocess, from the safety point of view, was proposed.•Chitosan particles were prepared and crosslinked with genipin and β-galactosidase.•Chitosan–genipin particles were ...more resistant than chitosan–glutaraldehyde particles.•Effective lactose conversion and synthesis of GOS using a non-toxic biocatalyst.
In order to develop safer processes for the food industry, we prepared a chitosan support with the naturally occurring crosslinking reagent, genipin, for enzyme. As application model, it was tested for the immobilization of β-d-galactosidase from Aspergillus oryzae. Chitosan particles were obtained by precipitation followed by adsorption of the enzyme and crosslinking with genipin. The particles were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The immobilization of the enzyme by crosslinking with genipin provided biocatalysts with satisfactory activity retention and thermal stability, comparable with the ones obtained with the traditional methodology of immobilization using glutaraldehyde. β-d-Galactosidase–chitosan–genipin particles were applied to galactooligosaccharides synthesis, evaluating the initial lactose concentration, pH and temperature, and yields of 30% were achieved. Moreover, excellent operational stability was obtained, since the immobilized enzyme maintained 100% of its initial activity after 25 batches of lactose hydrolysis. Thus, the food grade chitosan–genipin particles seem to be a good alternative for application in food process.
In the present work the role that 3-aminopropyltrimethoxysilane (APTMS) plays in the chitosan‑gold nanoparticles system was studied. For this purpose, gold nanoparticles (AuNP) (ca. 4.0 nm), were ...synthesized using chitosan as stabilizer and after, the APTMS, which presents both alkoxy and amine groups, was added to the system. No changes in both size and shape of the AuNP were observed. The addition of APTMS to chitosan produced a significant decrease in dynamic viscosity and this feature can contribute to the achievement of greater miscibility in the system. The AuNP dispersion containing APTMS was used to build a film on the surface of glass slide by using the drop-casting method. The gold amount on the resulting film was estimated as 17.5 μmol of gold atoms per cm2, in the nanoparticle form. The film was analyzed by UV–Vis, TEM, SEM, perfilometry and AFM. The film presented thickness of 36 μm, while the estimated roughness was lower than 1% of this value. The antimicrobial activity of the film based on chitosan, APTMS and gold nanoparticles was evaluated against Salmonella bacterium. The synergistic effect of the three components provided greater antimicrobial activity.
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•The role that APTMS plays in the synthesis of chitosan film containing AuNP•Homogeneous and low-roughness AuNP coating on glass surface using drop-casting•Antimicrobial activity of AuNP, chitosan and aminopropylsilane against Salmonella
The human papillomavirus (HPV) is associated with cervical abnormalities. People living with HIV are more susceptible to HPV. Campos dos Goytacazes implemented the quadrivalent HPV vaccine (4vHPV) ...for women living with HIV (WLWH) in 2011, 4 years before the Brazilian public vaccination program. We aimed to characterize the genomic diversity and predictors of HPV infection in WLWH through a prospective cohort study. After the consent form was received, a questionnaire was applied and an endocervical sample was collected. For genotyping, a microarray HPV technique was performed. Two intervention moments were performed: T1, the initial moment, with collection and vaccination; T2 moment, 2 years after T1. Univariate and multivariate analyses were performed. The T1 moment cohort was formed by 146 women,107 belonging to Group 1(HPV‐negative) and 39 to Group 2 (HPV‐positive). The variables age, marital status, number of children, number of sexual partners, and CD4 count were protective against HPV. The variables number of sexual partners, marital status, and the number of children lost significance in multivariate analysis. Concerning T2 moment, 42 patients were followed with three positive cases. The use of 4vHPV is beneficial for this population and should also be recommended at an age from 26 to 45 years inside the public vaccination program.
Key Points/Highlights
The prevalence of human papillomavirus (HPV) infection in women living with HIV (WLWH) was 26.7% (39 women).
Of 35 WLWH infected with recognized HPV types, 88.5% had a genotype included in 4vHPV included in the public program.
Brazilian Government should recommend 4vHPV for WLWH up to45 years.
This study aimed to investigate the kinetics, isotherms, and thermodynamics of biosorption of the cationic dye rhodamine B by a low-cost biosorbent prepared from
Aspergillus oryzae
cells. Culture ...medium composition (mineral salts, nitrogen source, and carbon source) influenced removal efficiency, and dye removal increased with increasing biosorbent concentrations until a plateau was reached at 10 g L
−1
. Temperature and dye concentration were directly related to removal, and the highest removal efficiency was obtained at 40 °C and 200 mg L
−1
of dye. The adsorption kinetics was best fitted to a pseudo-second-order model, and equilibrium data were well described by the Freundlich equation. Thermodynamic analysis indicated that the biosorption of rhodamine B by
A. oryzae
cells is physical in nature, spontaneous, and more favorable at higher temperatures and dye concentrations. Overall, the results suggest that inactivated
A. oryzae
biomass is a promising biosorbent for the removal of cationic dyes from wastewater.
Two Schiff bases were synthesized by reaction of 2-(4′-aminophenyl)benzoxazole derivatives with 4-N,N-diethylaminobenzaldehyde. UV–visible (UV–vis) and steady-state fluorescence in solution were ...applied in order to characterize its photophysical behavior. The Schiff bases present absorption in the UV region with fluorescence emission in the blue-green region, with a large Stokes’ shift. The UV–vis data indicates that each dye behaves as two different chromophores in solution in the ground state. The fluorescence emission spectra of the dye 5a show that an intramolecular proton transfer (ESIPT) mechanism takes place in the excited state, whereas a twisted internal charge transfer (TICT) state is observed for the dye 5b. Theoretical calculations were performed in order to study the conformation and polarity of the molecules at their ground and excited electronic states. Using density functional theory (DFT) methods at theoretical levels BLYP/Aug-SV(P) for geometry optimizations and B3LYP/6-311++G(2d,p) for single-point energy evaluations, the calculations indicate that the lowest energy conformations are in all cases nonplanar and that the dipole moments of the excited state relaxed structures are much larger than those of the ground state structures, which corroborates the experimental UV–vis absorption results.
In this work, silver nanoparticles were in situ synthesized inside of the mesopores of SBA-15 type silica. The new strategy of synthesis was planned to obtain highly dispersed nanoparticles, strongly ...adhered to the matrix and maintaining the textural characteristics of the SBA-15. In order to attain this purpose, an ionic silsesquioxane was used to anchor an anionic complex that acts as a silver source for the nanoparticle synthesis. The material was characterized by X-ray diffraction, UV–Visible spectroscopy, N
2
adsorption–desorption isotherms, thermogravimetric analysis, and transmission electron microscopy. The textural, morphological, structural, and chemical characteristics of the material allowed its use as a matrix to prepare a modified carbon paste electrode. The electrode was applied in the amoxicillin determination showing excellent performance. The prepared sensor presents sensitivity of 0.056 µA µmol L
−1
, low limit of detection of 0.35 µmol L
−1
, limit of quantification of 1.17 µmol L
−1
, and good reproducibility (6.1% relative standard deviation) for five different electrodes and good repeatability (3.9% relative standard deviation) for five successive measurements for the same electrode. The sensor shows high selectivity considering several organic compounds and inorganic salts as interfering agents. Additionally, the sensor presents excellent recovery in determination of commercial pills (98.6–102.4%) and whole cow milk (102.7%). The excellent performance of the sensor was interpreted taking into account the synergic effects of the textural properties and the silver nanoparticle sites available.
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