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Academic performance is an essential component of the constellation of factors that determine student success. It also plays a vital role in education, primarily as a concrete tool for evaluating the learning process of a student. Psychologists and researchers have utilized a variety of personality, attitude, cognitive style, and ability assessments to determine how students differ in processing, retaining, and retrieving learning information. Academic success is dependent on a positive learning experience. To achieve their learning goals, students regularly engage in activities such as reading, taking notes, and leading study groups. It can be categorized as either effective or ineffective based on the extent to which it assists the students. Thus, study habits provide dedicated and uninterrupted time for the pursuit of knowledge [1]. This determines the academic success of a student. Among the most important criteria for evaluating academic performance are study habits and attitudes. Good study habits are important in the lives of students [2]. They concluded that each student's success or failure is contingent on their study habits. Additionally, their success is contingent upon their skill, intelligence, and effort. There is a significant positive correlation between the students' good study habits, including homework completion, class participation, time management, concentration, and effort, and their academic performance [3]. Online instruction, correspondence courses, television, and the multimedia package format are all viable methods of education. Frequently, students enrolled in distance education programs face unforeseen increases in responsibilities and physiological, emotional, psychological, and social concerns. Because they lack the support of an immediate peer group, an instructor, or experience with the technology used to supply distance learning materials, online learning students, particularly novices, may find it difficult to comprehend the requirements of university study. According to surveys, individuals who are doubtful of their learning capacity choose to memorize information to finish projects and pass tests now that distant learning and remote teaching have become the standard. Students often have poor academic achievement due to their inability to comprehend the topic. Additionally, study habits add to the efficacy of this distant learning. To design a learning policy, the researchers propose determining the study habits of student nurses to reflect the lived experiences of PHINMA University of Pangasinan Nursing students in distant learning under the new norm. By doing so, we may develop a more effective plan, identify the students' study habits that influence their academic performance, and design activities that assist them to become more academically prepared. Key words: Distance Learning, Covid-19, Learning Policy, Challenges, Grieving

Porphyrins are differentiated π-conjugated compounds with unique photochemical and redox properties. The tetrapyrrole macrocycle core of porphyrins is extremely favorable for the complexation of metal ions, resulting in hybrid metal–organic molecules with good photocatalytic properties. Over the years, porphyrins have been extensively tested as photocatalysts in advanced oxidative processes for the degradation of various organic contaminants in water. Recently, the use of porphyrins supported on solid materials is viewed as one of the most effective strategies to obtain photocatalytic systems with superior properties and applicability. Supported porphyrins can form highly organized hybrid materials, with high electron conductivity and great photoreaction properties. Here we review concepts, development, and application of supported porphyrins/metalloporphyrins. The first sections present an overview of the water contamination problem, the fundamentals of the photocatalytic treatment of water, and the main properties of porphyrins. The following sections focus on the application of supported porphyrins in the photodegradation of common organic contaminants in water. The last two sections discuss the main mechanisms and limitations.

The physicochemical and structural characteristics of the magnetic materials can be modulable due to exposition to a magnetic field, which allows, for example, to enhance its adsorption performance. In this sense, this study describes the preparation of magnetic beads of alginate/polypyrrole/ZnFe

Protected areas such as natural parks provide a range of ecosystem services vital to human well-being. The common-pool-resource nature of natural parks has made them susceptible to overuse and degr...

Cu species (ions or nanoparticles) have gained considerable attention in many research fields, mainly in catalysis. In particular, the development of novel support materials, especially those based...

In this work, we have investigated the use of a heterogeneous catalyst based on reduced graphene oxide-grafted with carboxymethyl chitosan (rGO-CMCHT) and silver nanoparticles (AgNPs) for hydrogen generation through straightforward borohydride decomposition reaction. Thus, an rGO-CMCHT thin film containing AgNPs was successfully prepared by using a dip-coating technique. Characterization analysis indicated that rGO-CMCHT enhances the catalytic activity of AgNPs due to its intrinsic electric capacity (i.e., low electron-mobility resistivity). The experimental results showed that the prepared thin film has a remarkable catalytic activity that boosts hydrogen generation (maximum rate 180 × 102 mL min−1 g−1), achieving TOF values (480 min−1) that exceed the previously reported data. High TOF values were also obtained in aqueous and non-aqueous media using low amounts of catalyst, confirming its versatility. Reuse experiments demonstrated that thin film could be recycled and reused for at least ten consecutive reactions without losing catalytic efficiency. Spectroscopic analyses showed that AgNPs were not leached in the reaction medium after the reuse cycles, indicating that rGO-CMCHT stabilizes the nanoparticles efficiently. Finally, the prepared thin film also showed excellent catalytic performance catalytic towards the reduction of nitroaromatic compounds in aqueous and non-aqueous media, confirming its versatility for hydrogen production and hydrogenation reactions.

Recessive dystrophic epidermolysis bullosa (RDEB) patients develop poorly healing skin wounds that are frequently colonized with microbiota. Because T cells play an important role in clearing such pathogens, we aimed to define the status of adaptive T cell-mediated immunity in RDEB wounds. Using a non-invasive approach for sampling of wound-associated constituents, we evaluated microbial contaminants in cellular fraction and exudates obtained from RDED wounds. Infectivity and intracellular trafficking of inactivated Staphylococcus aureus was accessed in RDEB keratinocytes. S. aureus and microbial antigen-specific activation of RDEB wound-derived T cells were investigated by fluorescence-activated cell sorting-based immune-phenotyping and T-cell functional assays. We found that RDEB wounds and epithelial cells are most frequently infected with Staphylococcus sp. and Pseudomonas sp. and that S. aureus essentially infects more RDEB keratinocytes and RDEB-derived squamous cell carcinoma cells than keratinocytes from healthy donors. The RDEB wound-associated T cells contain populations of CD4

Dear editor,Videoconferencing became a popular platform for instructional delivery during the COVID-19 pandemic. With this sudden transition from traditional face-to-face instruction to a virtual p...

Bone marrow mesenchymal stem/stromal cells (BM-MSCs) have immunoregulatory capacity; therefore, they have been used in different clinical protocols in which it is necessary to decrease the immune response. This capacity is mainly regulated by TNF-α and IFN-γ, and it has been observed that cell-cell contact, mainly mediated by ICAM-1, is important for MSCs to carry out efficient immunoregulation. Therefore, in the present work, we analyzed the effect of TNF-α alone or in combination with IFN-γ on the expression of ICAM-1. Besides, given the importance of cell contact in the immunoregulatory function of MSCs, we analyzed whether these cells release ICAM-1+ microvesicles (MVs). Our results show for the first time that TNF-α is capable of increasing the early expression of ICAM-1 in human BM-MSCs. Also, we observed that TNF-α and IFN-γ have a synergistic effect on the increase in the expression of ICAM-1. Furthermore, we found that BM-MSCs exposed to an inflammatory environment release MVs enriched in ICAM-1 (MVs-ICAM-1high). The knowledge generated in this study will contribute to the improvement of in vitro conditioning protocols that favor the therapeutic effect of these cells or their products.

Novel poly(vinyl alcohol)/chondroitin sulfate (PVA/CS) composite hydrogels containing hydroxyapatite (HA) or Sr-doped HA (HASr) particles were synthesized by a freeze/thaw method and characterized aiming towards biomedical applications. HA and HASr were synthesized by a wet-precipitation method and added to the composite hydrogels in fractions up to 15 wt%. Physical-chemical characterizations of particles and hydrogels included scanning electron microscopy, energy-dispersive spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetry, porosity, compressive strength/elastic modulus, swelling degree, and cell viability. Particles were irregular in shape and appeared to have narrow size variation. The thermal behavior of composite hydrogels was altered compared to the control (bare) hydrogel. All hydrogels exhibited high porosity. HA/HASr particles reduced total porosity without reducing pore size. The mechanical strength was improved as the fraction of HA or HASr was increased. HASr particles led to a faster water uptake but did not interfere with the total hydrogel swelling capacity. In cell viability essay, increased cell growth (above 120%) was observed in all groups including the control hydrogel, suggesting a bioactive effect. In conclusion, PVA/CS hydrogels containing HA or HASr particles were successfully synthesized and showed promising morphological, mechanical, and swelling properties, which are particularly required for scaffolding.

Refractoriness remains as one of the challenges in patients with lymphoma under chemotherapy, and among biological regulators in cells driving this type of response are microRNAs (miRNAs). Different genes are constantly turned on or off according to the miRNAs expression profiles affecting the drug response in patients and their stability in serum and plasma makes them potential prognostic biomarkers in several diseases. Here we described a profile of miRNAs in plasma of diffuse large B cell lymphoma (DLBCL) patients. miRNA expression arrays were carried using pre-treatment plasma samples of sixteen patients, followed by a comparison between the responder and the non-responders. After six cycles of R–CHOP treatment, twelve out of sixteen patients were clinically diagnosed with complete response while in four patients no clinical response was observed. Between these groups, a signature of fifteen differential expressed miRNAs was found. The circulating miRNAs in plasma of patients with no response were related to the drug resistance in other types of cancer, by targeting genes involved in cell proliferation and apoptosis, among other cell processes.

A hybrid film of chitosan/poly(vinyl alcohol)/cationic Fe(III)-porphyrin (Cht/PVA-FeTMPyP) was synthesized to act as a Fenton-like catalyst to decolorize methyl orange and methyl red azo dyes. The Cht/PVA-FeTMPyP film was characterized by different analytical and microscopy techniques, which indicated that the metalloporphyrin affects different properties of the hybrid film. Batch experiments revealed that the hybrid film exhibits enhanced catalytic activity towards dyes decolorization in the presence of H2O2 as compared to the “free” FeTMPyP. Fast decolorization rates as high as 90 min were observed for both azo dyes under mild conditions (pH 7 and room temperature), even at low concentrations of the catalyst in H2O2. After the decolorization, FTIR analysis showed that simple molecules are released as by-products. Moreover, the hybrid film performed well in cyclic runs without leaching out iron ions or losing its catalytic activity. All these features associated with its ease handling ranks the Cht/PVA-FeTMPyP hybrid film as a promising heterogeneous Fenton-like catalyst for the decomposition of azo dyes in water.

Pectin (Pec) and cellulose microfibers (CF) extracted from orange waste were combined to form composite beads with enhanced adsorption capacity. Such beads were extensively tested in the removal of multi-metal ions from water. A factorial design approach was conducted to establish the optimum conditions for adsorption of Cd(II), Cu(II), and Fe(II) on Pec-CF beads. Batch adsorption experiments revealed that removal efficiency of such metal ions falls in the range of 94–58% and it followed the order Fe(II) > Cu(II) > Cd(II). The maximum Cd(II), Cu(II) and Fe(II) adsorption capacities calculated from the Langmuir isotherm were 192.3, 88.5 and 98.0 mg/g, respectively. FTIR analysis suggests that the functional groups on Pec-CF beads (binding sites) favor the adsorption of such metal ions. Desorption and reuse experiments demonstrated the beads could be used for at least five consecutive adsorption/desorption cycles. Our finds suggest the Pec-CF beads can serve as an efficient adsorbent for the removal of multi-metal ions from wastewater. Keywords: Pectin, Cellulose microfibers, Beads, Metal removal, Wastewater treatment

Polysaccharide-based materials have been claimed as efficient supports for different species used in catalysis, such as transition metal ions. Overall, the immobilization of metal ions on these materials brings several attractive aspects in terms of economy and catalytic activity. In this study, we demonstrated the facile immobilization of Cu2+ ions on alginate-based microspheres (Alg–Cu2+) via a straightforward ion exchange process. The prepared microspheres were characterized in detail by different techniques. As assessed, the ion-exchange process promoted some change in the properties of the microspheres, which was ascribed to the strong interaction forces established between the alginate matrix and Cu2+ ions. The catalytic activity of Alg–Cu2+ was investigated towards the one-pot synthesis of 4-organylselanyl-1H-pyrazole derivatives via cyclocondensation reactions of diketones and hydrazines, followed by direct selenation reactions. In general lines, the starting reagents were efficiently converted via one-pot reactions to different derivatives in moderate to excellent yields. Moreover, the Alg–Cu2+ catalysts still maintained satisfactory catalytic activity even after five consecutive runs. These results indicate that the Alg–Cu2+ microspheres prepared in this study are a promising heterogeneous catalytic system for the synthesis of this class of substituted pyrazoles.

Microparticles with oval-shape morphology and rough and porous surfaces were prepared by polyelectrolyte complexation of carboxymethyl starch (CMS) and chitosan (Cs). CMS with DS of 0.5, the polyanionic moiety, was synthesized from rice starch with low content of amylose (6%). A preliminary investigation revealed that this kind of starch is more susceptive to esterification than rice starches with higher contents of amylose. The CMS/Cs microparticles showed higher chemical and thermal stability than microparticles prepared by conventional ionotropic crosslinking of Cs with TPP ions. The carboxymethyl groups of CMS are more efficient to neutralize the positive groups of Cs and, also, enhance the entrapment of bovine serum albumin (BSA) in the CMS/Cs matrix as compared to Cs/TPP. In vitro experiments conducted in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8) with the testing microparticles revealed that the CMS/Cs-BSA microparticles exhibit a highlighted pH-dependent release profile. This desirable property allows controlling the release of BSA more efficiently, which minimizes undesirable issues (e.g. burst effect and non-sustained release). Furthermore, the BSA release from CMS/Cs-BSA microparticles in SIF follows an ideal Zero-order kinetics, which is very attractive for a drug delivery system. Therefore, microparticles based on CMS/Cs polyelectrolyte complex may be promising to control the drug release in specific regions of the gastrointestinal tract. Keywords: Carboxymethyl starch, Chitosan, Polyelectrolyte complex, Drug release, Controlled release, Bovine serum albumin

Adipocytes are the main cell type in adipose tissue, which is a critical regulator of metabolism, highly specialized in storing energy as fat. Adipocytes differentiate from multipotent mesenchymal stromal cells (hMSCs) through adipogenesis, a tightly controlled differentiation process involving close interplay between metabolic transitions and sequential programs of gene expression. However, the specific gears driving this interplay remain largely obscure. Additionally, the metabolite nicotinamide adenine dinucleotide (NAD+) is becoming increasingly recognized as a regulator of lipid metabolism, and a promising therapeutic target for dyslipidemia and obesity. Here, we explored how NAD+ bioavailability controls adipogenic differentiation from hMSC. We found a previously unappreciated repressive role for NAD+ on adipocyte commitment, while a functional NAD+-dependent deacetylase SIRT1 appeared crucial for terminal differentiation of pre-adipocytes. Repressing NAD+ biosynthesis during adipogenesis promoted the adipogenic transcriptional program, while two-photon microscopy and extracellular flux analyses suggest that SIRT1 activity mostly relies on the metabolic switch. Interestingly, SIRT1 controls subcellular compartmentalization of redox metabolism during adipogenesis.

Background: During pregnancy, the placenta is an extremely important organ as it secretes its own hormones, e.g. insulin-like growth factor 1 (IGF-1), to ensure proper intrauterine fetal growth and development. Ethanol, an addictive and widely used drug, has numerous adverse effects during pregnancy, including fetal growth restriction (FGR). To date, the molecular mechanisms by which ethanol triggers its toxic effects during pregnancy, particularly in the placenta, are not entirely known. For this reason, a murine model of partial IGF-1 deficiency was used to determine ethanol alterations in placental morphology and AAH expression. Methods: Heterozygous (HZ, Igf1+/-) female mice were given 10% ethanol during 14 days as an acclimation period and throughout pregnancy. HZ female mice given water were used as controls. At gestational day 19, pregnant dams were sacrificed, placentas were collected and genotyped for subsequent studies. Results: IGF-1 deficiency and ethanol consumption during pregnancy altered placental morphology, and decreased placental efficiency and aspartyl/asparaginyl β-hydroxylase (AAH) expression in placentas from all genotypes. No differences were found in Igf1, Igf2, Igf1r and Igf2r mRNA expression in placentas from all groups. Conclusions: IGF-1 deficiency and ethanol consumption throughout gestation altered placental development, suggesting the crucial role of IGF-1 in the establishment of an adequate intrauterine environment that allows fetal growth. However, more studies are needed to study the precise mechanism to stablish the relation between both insults.

Polymer aerogels of poly(acrylic acid)/poly(vinyl alcohol) (labeled as CPA) were prepared and tested as support materials for different cationic porphyrin organocatalysts (denoted as TMPyP, TMPyPZn, or TMPyPMn). The hybrid aerogels were characterized by various techniques, while their catalytic activity was investigated towards the photodegradation of amoxicillin (AMX), caffeine (CAF), and naproxen (NPX) under artificial visible light. Photodegradation experiments revealed that the CPA-TMPyPMn aerogel shows superior catalytic potential when compared to the others aerogels or the "free" TMPyPMn porphyrin. All pharmaceuticals were quickly degraded (before 60 min) and high COD removal rates (greater than95%) were achieved at pH 7.0 and room temperature. The CG-MS data confirm the complete degradation of all tested pharmaceuticals catalyzed by CPA-TMPyPMn. Recycling experiments revealed that this hybrid aerogel keeps its photocatalytic efficiency for at least 15 reuse runs. In short, this original photocatalytic system is promising to mediate the removal of pharmaceutical contaminants from the aqueous medium.

Driven by the need for remote learning, the COVID-19 pandemic led to the rise of use of videoconferencing tools. Scholars began noticing an emerging phenomenon of feeling tired and exhausted during virtual meetings. This study determined the predictors of videoconference or Zoom fatigue among nursing students in a large, private, non-sectarian university in the Philippines. This cross-sectional online survey involves 597 nursing students in the Philippines using the Zoom Exhaustion and Fatigue Scale. Multiple linear regression analysis was used to examine predictors of videoconference fatigue. Results indicated that nursing students experienced high levels of videoconference fatigue. Gender, self-reported academic performance, Internet connection stability, attitude toward videoconferencing, frequency, and duration of videoconferences predicted videoconference fatigue. The regression model explained 25.3% of the variances of the videoconference fatigue. Videoconference fatigue is relatively prevalent and may be taking its toll on nursing students. Developing strategic interventions that can protect or mitigate the impact of fatigue during virtual meetings is needed.

Polysaccharide-based hydrogels are particularly attractive materials for biomedical applications. However, their use is restricted due to their brittleness and poor mechanical properties. Here, to overcome such limitations, we report an original, green, simple, and efficient strategy to synthesize a polysaccharide-based hydrogel of chitosan (Cht) and a vinyl-functionalized PVA (PVA-MA), a non-toxic synthetic polymer that is widely known to improve the mechanical properties and stability of materials containing polysaccharides. The hydrogel was crosslinked through an aza-Michael addition among the amino groups of Cht with the vinyl moieties of PVA-MA catalyzed by boric acid (B(OH)3), an eco-friendly inorganic compound. Characterization analyses revealed that the prepared hydrogel has a porous-like morphology, an outstanding liquid uptake capacity (>665%), and improved stability in a physiological fluid for long periods. In summary, this original and simple strategy showed to be efficient in the synthesis of hydrogels with attractive properties for the biomedical field application.

Methotrexate (MTX) is a common drug used for rheumatoid arthritis (RA) treatment; however, a series of adverse effects associated with its oral or subcutaneous administration is reported. Transdermal delivery of MTX is an alternative to abate these issues, and the use of drug delivery systems (DDS) based on polymeric films presents an impressive potential for this finality. Based on this, in this study, we report the preparation of films made by cationic starch (CSt), poly(vinyl alcohol) (PVA), and chondroitin sulfate (ChS) to incorporate and release MTX, as well as the in vivo evaluation in model of rheumatoid arthritis in mice. CSt/PVA and CSt/PVA/ChS-based films (with and without MTX) were prepared using a simple protocol under mild conditions. The films loaded with 5 w/w-% of MTX exhibited appreciable drug loading efficiency and distribution. The MTX permeation through the layers of porcine skin demonstrated that most of the drug permeated was detected in the medium, suggesting that the formulation can provide a systemic absorption of the MTX. In vivo studies performed in an arthritis-induced model in mice demonstrated that the MTX-loaded films were able to treat and attenuate the symptoms and the biochemical alterations related to RA (inflammatory process, oxidative stress, and nociceptive behaviors). Besides, the pharmacological activity of MTX transdermally delivery by the CSt/PVA and CSt/PVA/ChS films was comparable to the MTX orally administered. Based on these results, it can be inferred that both films are prominent materials for incorporation and transdermal delivery of MTX in a practical and non-invasive manner.

Silver nanoparticles (AgNPs) were synthesized using an innovative strategy that makes use of tangerine peels extract, which acts as a reducing and stabilizing agent. This eco-friendly synthetic route allowed obtaining spherical nanoparticles with narrow size distribution (19.2 ± 6.7 nm) within a short reaction time (40 min). Later, the AgNPs suspension was entrapped in a poly(vinyl alcohol) (PVA) matrix forming a hybrid hydrogel (PVA-gel/AgNPs), which was characterized by different techniques. Its catalytic activity was explored in the reduction of nitrobenzene to aniline in aqueous media. The reaction catalyzed by PVA-gel/AgNPs exhibited kinetics (kapp ≈ 2.07 × 10−3 min−1) and energy of activation (Ea ≈ 50.36 kJ mol−1) comparable to or lower than similar reactions catalyzed by other metals. Moreover, a better catalytic performance was noticed to the hybrid hydrogel as compared to “free” AgNPs, highlighting their entrapment within the hydrogel. The anchoring of the AgNPs in the hydrogel network, prevents their aggregation and leaching. The hybrid hydrogel is recovered quickly from the reaction medium, and it can be successfully reused for six consecutive runs without significant loss of its activity. Overall, it is presented here a cheap, efficient, and eco-friendly methodology to synthesize AgNPs and newly hybrid hydrogels, which have the potential to catalyze the reduction of nitroaromatic compounds.

A superabsorbent hydrogel composite based on a starch-grafted-poly(sodium acrylate) matrix filled with husk rice ash (RHA) was synthesized and tested as a soil conditioner to enhance the melon seedling growth. The incorporation of 20 wt% of RHA in the hydrogel matrix endowed the composite with an outstanding liquid uptake capacity (42,000%). Field experiments were performed to investigate the effect of the amount of hydrogel, type o subtract (sandy soil and coconut fibers) and type of soil (sandy soil and clay soil) on several parameters related to the plants' growth process. Overall, the plants cultivated in coconuts fibers exhibited the highest plant growth (5.60 cm) as compared to the plants cultivated in sandy soil (4.12 cm); however, the conditioning effect was limited in this case. Also, in this experiment, the amount of hydrogel used only affected the plant roots size. Additional analyses showed that the plant growth process is enhanced in clay soil as compared to sandy soil. Here, a synergistic beneficial effect was noticed between the type of soil and the amount of hydrogel used as conditioners. A small amount of hydrogel (≤ 0.75 wt%) had an apparent positive effect on the plants' growth process when they are cultivated in clay soils. In summary, the results presented here allow inferring that these composite hydrogels can be ranked as promising materials for use as soil conditioners.

In this study, hydrogel composites based on chitosan-g-poly(acrylic acid) matrices filled with cellulose nanowhiskers (CNWs) were prepared, and their ability to adsorb Pb(II) and Cu(II) ions from the water was investigated. A factorial design approach was performed to examine the effect of some selected parameters on the adsorption process. The optimized conditions revealed that the highest adsorption of Pb(II) (818.4 mg/g) and Cu(II) (325.5 mg/g) is obtained within 30 min, at pH 4.0, using 20 mg of the hydrogel composite containing 10 w/w-% of CNWs. As assessed, functional groups available in the hydrogel matrix and CNWs act as coordination sites for the adsorption. The Langmuir type I isotherm fitted the experimental adsorption data indicating monolayer formation drive the adsorption process. The maximum adsorption capacity of the hydrogel composite prepared in this study concerning the two selected metals was comparable or better than those reported to other similar adsorbent materials. Also, adsorption kinetics followed the pseudo-second-order model. Desorption studies indicate that the post-utilized hydrogel composite can be regenerated and reused again in new adsorption processes without a dramatic loss of efficiency. The results presented here shed light on some essential aspects related to the design and application of hydrogel composites containing nanocellulose in the adsorption process. Moreover, these findings may be helpful to obtain adsorbent materials for practical applications.

In this study, Schiff bases of chitosan (CS) were synthesized using citronellal, citral, and their derivatives containing selenium and sulfur. Organoselenium and organosulfur compounds show attractive biological and pharmaceutical activities, which can be beneficial to CS-based materials. From the characterization analyses, it was found that the CS-derivatives containing organoselenium and organosulfur compounds exhibited the highest conversion degrees (23 and 28%). Biological assays were conducted using films prepared by the blending of CS-derivatives and poly(vinyl alcohol). The antimicrobial evaluation indicated that the film prepared with the sulfur-containing CS was the most active against the tested pathogens (Escherichia coli, Staphylococcus aureus, and Candida albicans) since it reduced considerably their counts (42.5%, 17.4%, and 18.7%). Finally, in vivo assays revealed that this film attenuates atopic dermatitis-like symptoms in mice by suppressing the increase of myeloperoxidase (MPO) activity and reactive species (RS) levels induced by 2,4-dinitrochlorobenzene (DNCB). In summary, CS-derivatives containing chalcogens, mainly organosulfur, are potential candidates for biomedical applications such as for the treatment of chronic skin diseases.

A new electrode based on glassy carbon modified with an alginate film cross-linked with glutaraldehyde containing immobilized carbon black particles was successfully developed and applied for the determination of paraquat (PQ), a herbicide widely used for broadleaf weed control. Different polysaccharides (alginate, cellulose, pectin, starch, and chitosan) were investigated for the immobilization process, and alginate presented the highest chemical modifier potential for PQ determination. Additionally, the influence of chemical cross-linking agents (glutaraldehyde and epichlorohydrin) on the morphology, electrochemical response, and film stability was investigated. All experimental conditions were optimized, including the supporting electrolyte conditions (composition, pH, and concentration) and square wave voltammetry technical parameters. Under the optimized experimental conditions, the PQ analytical curve was linear from 0.4 to 2.0 mg L-1 and the limits of detection and quantification were 0.06 and 0.19 mg L-1, respectively. The proposed electrode is easy to obtain, stable, selective, sensitive, and low cost and was successfully applied for PQ determination in environmental and beverage samples.

In this contribution, we a report a facile synthesis and stabilization of copper nanoparticles (CuNPs) in a superporous hydrogel based on chitosan (Cs) and poly(vinyl alcohol) (PVA). The functional groups of Cs and PVA stabilized the CuNPs and, as a result, several properties (e.g. thermal, morphological and liquid uptake) of the final materials exhibited remarkable improvements in terms of stability and catalytic activity. The metallic nature of CuNPs was confirmed by XRD and XPS analyses. From the XRD data, the Cu nanoparticle size was estimated to range from 3 to 7 nm. Moreover, EDS mapping analysis revealed that the CuNPs are homogeneously distributed throughout the hydrogel surface. The Cs/PVA-CuNP hydrogel was found to be an excellent catalyst for the synthesis of 1,2,3-triazoles using phenyl azide and phenylacetylene as model substrates under mild optimized conditions (>90% yield). Reuse studies revealed that this original CuNP-containing catalyst can be employed in at least 5 consecutive cycloaddition reactions without demonstrating a clear loss of efficiency. Moreover, the copper leaching from the hydrogel matrix was negligible during these consecutive reactions under the investigated conditions. The Cs/PVA-CuNP hydrogel could also efficiently catalyze cycloaddition reactions involving different substituted azide and alkyne precursors.

Ethanol use during pregnancy is a risk factor for developing adverse outcomes. Its metabolism by cytochrome P450 2E1 (CYP2E1) produces radical oxygen species (ROS), promoting cellular injury and apoptosis. To date, no studies have been conducted to elucidate the teratogenic effects due to both IGF-1 deficiency and ethanol consumption in mice placentas. The aim of this study is to determine the effect of ethanol consumption on the placenta and liver of partially IGF-1-deficient mice, the role of metabolism via CYP2E1, and the antioxidant enzyme system. Heterozygous (HZ, Igf1+/−) pregnant female mice were given water or 10% ethanol. Wild-type (WT, Igf1+/+) female mice were used as controls. At gestational day 19, pregnant dams were euthanized, and maternal liver and placentas were collected. Pregnant HZ dams were smaller than controls, and this effect was higher due to ethanol consumption. Cyp2e1 gene was overexpressed in the liver of HZ pregnant dams exposed to ethanol; at the protein level, CYP2E1 is reduced in placentas from all genotypes. The antioxidant enzymatic system was altered by ethanol consumption in both the maternal liver and placenta. The results in this work hint that IGF-1 is involved in intrauterine development because its deficiency exacerbates ethanol’s effects on both metabolism and the placenta.

Wound healing can be a painful and time-consuming process in patients with diabetes mellitus. In light of this, the use of wound healing devices could help to accelerate this process. Here, cellulose-based films loaded with vitamin C (VitC) and/or propolis (Prop), two natural compounds with attractive properties were engineered. The starting materials and the cellulose-based films were characterized in detail. As assessed, vitamin C can be released from the Cel-PVA/VitC and Cel-PVA/VitC/Prop films in a controlled manner. In vitro antibacterial activity studies showed a reduction of bacteria counts (Escherichia coli and Staphylococcus aureus) after Cel-PVA/VitC, Cel-PVA/Prop, and Cel-PVA/VitC/Prop treatments. Moreover, we examined the antibacterial and wound healing properties of the cellulose-based films in a streptozotocin (STZ)-induced diabetic animal model. Diabetic mice exhibited impaired wound healing while the Cel-PVA/VitC/Prop treatment increased the wound closure. A marked reduction in bacterial counts present in the wound environment of diabetic mice was observed after Cel-PVA/VitC, Cel-PVA/Prop and Cel-PVA/VitC/Prop treatment. Histological analysis demonstrated that the non-treated diabetic mice group did not exhibit adequate wound healing while the treated group with Cel-PVA/VitC and Cel-PVA/VitC/Prop films presented good cicatricial response. Furthermore, these novel eco-friendly films may represent a new therapeutic approach to accelerate diabetic wound healing.