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1.
PLoS One ; 19(5): e0300145, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38743740

RESUMEN

Integration of renewable energy sources (RES) to the grid in today's electrical system is being encouraged to meet the increase in demand of electrical power and also overcome the environmental related problems by reducing the usage of fossil fuels. Power Quality (PQ) is a critical problem that could have an effect on utilities and consumers. PQ issues in the modern electric power system were turned on by a linkage of RES, smart grid technologies and widespread usage of power electronics equipment. Unified Power Quality Conditioner (UPQC) is widely employed for solving issues with the distribution grid caused by anomalous voltage, current, or frequency. To enhance UPQC performance, Fractional Order Proportional Integral Derivative (FOPID) is developed; nevertheless, a number of tuning parameters restricts its performance. The best solution for the FOPID controller problem is found by using a Coati Optimization Algorithm (COA) and Osprey Optimization Algorithm (OOA) are combined to make a hybrid optimization CO-OA algorithm approach to mitigate these problems. This paper proposes an improved FOPID controller to reduce PQ problems while taking load power into account. In the suggested model, a RES is connected to the grid system to supply the necessary load demand during the PQ problems period. Through the use of an enhanced FOPID controller, both current and voltage PQ concerns are separately modified. The pulse signal of UPQC was done using the optimal controller, which analyzes the error value of reference value and actual value to generate pulses. The integrated design mitigates PQ issues in a system at non-linear load and linear load conditions. The proposed model provides THD of 12.15% and 0.82% at the sag period, 10.18% and 0.48% at the swell period, and 10.07% and 1.01% at the interruption period of non-linear load condition. A comparison between the FOPID controller and the traditional PI controller was additionally taken. The results showed that the recommended improved FOPID controller for UPQC has been successful in reducing the PQ challenges in the grid-connected RESs system.


Asunto(s)
Algoritmos , Energía Renovable , Suministros de Energía Eléctrica , Modelos Teóricos , Electricidad
2.
PLoS One ; 19(5): e0286356, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38739580

RESUMEN

INTRODUCTION: While a number of studies have examined the nutritional impacts of agroecological interventions, few have examined impacts on child development, maternal and child anemia, and men's dietary diversity. Moreover, there have been few such evaluations at scale. We evaluated the impact of a large-scale, multi-component food-based nutrition intervention involving homestead food production, nutrition counselling, cooking demonstrations, and crop planning exercises. METHODS: A cross-sectional assessment was conducted in 2021-2022 of 50 intervention villages where the nutrition-sensitive agroecology program had been implemented since 2018 and 79 control villages where only the agroecology program had been implemented. Data on self-reported dietary intake, caregiver-reported early child development, anthropometric measurements, and hemoglobin concentrations were collected using standardized procedures by trained Nutrition Farming Fellows, who were also responsible for implementing the program. RESULTS: A sample of 3,511 households (1,121 intervention and 2,390 control) participated in the survey. Dietary diversity scores (DDS) among women and men were mean (SD) 6.53 (±1.62) and 6.16 (±1.65), respectively, in intervention villages and 5.81 (±1.58) and 5.39 (±1.61), respectively, in control villages (p<0.01). DDS among children 6-24 months of age in intervention and control villages was 2.99 (±1.52) and 2.73 (±1.62), respectively (p<0.01). Children <2 years of age were less likely to be anemic in intervention versus control villages (59% versus 69%, p<0.01). Children 18-35 months age in intervention villages had higher child development scores than children in control villages (all p<0.05). CONCLUSION: Nutrition-sensitive agroecological programs may be effective in improving diets, nutrition, and child development in rural India.


Asunto(s)
Agricultura , Desarrollo Infantil , Dieta , Estado Nutricional , Humanos , India , Masculino , Femenino , Preescolar , Desarrollo Infantil/fisiología , Estudios Transversales , Agricultura/métodos , Lactante , Adulto , Niño , Población Rural
3.
Microb Pathog ; 191: 106677, 2024 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-38705217

RESUMEN

A novel endophytic Streptomyces griseorubens CIBA-NS1 was isolated from a salt marsh plant Salicornia sp. The antagonistic effect of S. griseorubens against Vibrio campbellii, was studied both in vitro and in vivo. The strain was validated for its endophytic nature and characterized through scanning electron microscopy, morphological and biochemical studies and 16SrDNA sequencing. The salinity tolerance experiment has shown that highest antibacterial activity was at 40‰ (16 ± 1.4 mm) and lowest was at 10 ‰ salinity (6.94 ± 0.51 mm). In vivo exclusion of Vibrio by S. griseorubens CIBA-NS1 was studied in Penaeus indicus post larvae and evaluated for its ability to improve growth and survival of P. indicus. After 20 days administration of S. griseorubens CIBA-NS1, shrimps were challenged with V. campbellii. The S. griseorubens CIBA-NS1 reduced Vibrio population in test group when compared to control, improved survival (60.5 ± 6.4%) and growth, as indicated by weight gain (1.8 ± 0.05g). In control group survival and growth were 48.4 ± 3.5% and 1.4 ± 0.03 g respectively. On challenge with V. campbellii, the S. griseorubens CIBA-NS1 administered group showed better survival (85.6 ± 10%) than positive control (64.3 ± 10%). The results suggested that S. griseorubens CIBA-NS1 is antagonistic to V. campbellii, reduce Vibrio population in the culture system and improve growth and survival. This is the first report on antagonistic activity of S. griseorubens isolated from salt marsh plant Salicornia sp, as a probiotic candidate to prevent V. campbellii infection in shrimps.

5.
Front Hum Neurosci ; 18: 1369862, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38660014

RESUMEN

Attention deficit/hyperactivity disorder (ADHD) is a neuropsychological disorder that occurs in children and is characterized by inattention, impulsivity, and hyperactivity. Early and accurate diagnosis of ADHD is very important for effective intervention. The aim of this study is to develop a computer-aided approach to detecting ADHD using electroencephalogram (EEG) signals. Specifically, we explore a Gabor filter-based statistical features approach for the classification of EEG signals into ADHD and healthy control (HC). The EEG signal is processed by a bank of Gabor filters to obtain narrow-band signals. Subsequently, a set of statistical features is extracted. The computed features are then subjected to feature selection. Finally, the obtained feature vector is given to a classifier to detect ADHD and HC. Our approach achieves the highest classification accuracy of 96.4% on a publicly available dataset. Furthermore, our approach demonstrates better classification accuracy than the existing methods.

6.
J Biomed Mater Res A ; 2024 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-38560769

RESUMEN

The Fe-Mn alloys are potential candidates for biodegradable implant applications. However, the very low degradation rates of Fe-Mn alloys in the physiological environment are a major disadvantage. In this study, the degradation rate of a Fe-20Mn alloy was improved using the groove pressing (GP) technique. Hot rolled sheets of 2 mm thickness were subjected to GP operation at 1000°C. Uniform fine-grained (UFG) Fe-Mn alloys were obtained using the GP technique. The influence of GP on the microstructure, mechanical properties, degradation behavior in simulated body fluid (SBF), surface wettability, biomineralization, and cytocompatibility was investigated and compared to the annealed (A Fe-Mn) and rolled (R Fe-Mn) sample. The groove-pressed Fe-Mn (G Fe-Mn) alloy had a grain size of approximately 40 ± 16 µm whereas the A Fe-Mn and R Fe-Mn samples had grain sizes of 303 ± 81 and 117 ± 14.5 µm, respectively. Enhanced strength and elongation were also observed with the G Fe-Mn sample. The potentiodynamic polarization test showed the highest Icorr, lowest polarization resistance, and lowest Ecorr for the G Fe-Mn sample among all other samples indicating its higher degradation rate. The weight loss data from immersion tests also shows that the percentage of weight loss increases with time indicating the accelerated degradation behavior of the sample. The static immersion test showed an enhancement in weight loss of 0.46 ± 0.02% and 1.02 ± 0.05% for R Fe-Mn and G Fe-Mn samples, respectively, than A Fe-Mn sample (0.31 ± 0.03%) after 56 days in immersion in SBF. The greater biomineralization tendency in UFG materials is confirmed by the G Fe-Mn sample's stronger hydroxyapatite deposition. When compared to the A Fe-Mn and R Fe-Mn samples, the G Fe-Mn sample has a better wettability, which promotes higher cell adhesion and vitality, showing higher biocompatibility. This study demonstrates that Fe-20Mn processed by GP has potential applications for the manufacture of biodegradable metallic implants.

7.
Int J Biol Macromol ; 268(Pt 2): 131724, 2024 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-38653427

RESUMEN

The emergence of novel well-defined biological macromolecular architectures containing fluorine moieties displaying superior functionalities can satisfactorily address many biomedical challenges. In this research, ABA- and AB-type glucose-based biological macromolecules were synthesized using acryl-2,3,4,6-tetra-O-acetyl-D-glucopyranoside with pentafluorophenyl (FPM), pentafluorobenzyl (FBM), phenyl (PM) and benzyl (BM) methacrylate-based macro-RAFT agents following RAFT polymerization. The macro-RAFT agents and the corresponding copolymers were characterized by 19F, 1H, and 13C NMR and FTIR spectroscopic techniques to understand the chemical structure, molecular weight by size-exclusion chromatography, thermal analysis by TGA and DSC. Thermal stability (Td5%) of the FPM and FBM fluoro-based polymers was observed in the range of 219-267 °C, while the non-fluoro PM and BM polymers exhibited in the range of 216-264 °C. Among the macro-RAFT agents, PFPM (107 °C, ΔH: 0.613 J/g) and PPM (103 °C, ΔH: 0.455 J/g) showed higher Tm values, while among the block copolymers, PFBM-b-PG (123 °C, ΔH: 0.412 J/g) and PG-b-PFPM-b-PG (126 °C, ΔH: 0.525 J/g) exhibited higher Tm values. PFBMT and PPM macro-RAFT agents, PPM-b-PG and PG-b-PPM-b-PG copolymer spin-coated films showed the highest hydrophobicity (120°) among the synthesized polymers. The block copolymers exhibited self-assembled segregation by using relatively hydrophobic segments as the core and hydrophilic moieties as the corona. Synthesized biological macromolecules exhibit maximum antibacterial activity towards S. aureus than E. coli bacteria. Fluorophenyl (PFPM) and non-fluorobenzyl-based (PBMT) macro-RAFT agents exhibit low IC50 values, suggesting high cytotoxicity. All the triblock copolymers exhibit lesser cytotoxicity than the di-block polymers.

8.
Am J Physiol Endocrinol Metab ; 326(5): E626-E639, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38536037

RESUMEN

Loss of ovarian function imparts increased susceptibility to obesity and metabolic disease. These effects are largely attributed to decreased estradiol (E2), but the role of increased follicle-stimulating hormone (FSH) in modulating energy balance has not been fully investigated. Previous work that blocked FSH binding to its receptor in mice suggested this hormone may play a part in modulating body weight and energy expenditure after ovariectomy (OVX). We used an alternate approach to isolate the individual and combined contributions of FSH and E2 in mediating energy imbalance and changes in tissue-level metabolic health. Female Wistar rats were ovariectomized and given the gonadotropin releasing hormone (GnRH) antagonist degarelix to suppress FSH production. E2 and FSH were then added back individually and in combination for a period of 3 wk. Energy balance, body mass composition, and transcriptomic profiles of individual tissues were obtained. In contrast to previous studies, suppression and replacement of FSH in our paradigm had no effect on body weight, body composition, food intake, or energy expenditure. We did, however, observe organ-specific effects of FSH that produced unique transcriptomic signatures of FSH in retroperitoneal white adipose tissue. These included reductions in biological processes related to lipogenesis and carbohydrate transport. In addition, rats administered FSH had reduced liver triglyceride concentration (P < 0.001), which correlated with FSH-induced changes at the transcriptomic level. Although not appearing to modulate energy balance after loss of ovarian function in rats, FSH may still impart tissue-specific effects in the liver and white adipose tissue that might affect the metabolic health of those organs.NEW & NOTEWORTHY We find no effect of follicle-stimulating hormone (FSH) on energy balance using a novel model in which rats are ovariectomized, subjected to gonadotropin-releasing hormone antagonism, and systematically given back FSH by osmotic pump. However, tissue-specific effects of FSH on adipose tissue and liver were observed in this study. These include unique transcriptomic signatures induced by the hormone and a stark reduction in hepatic triglyceride accumulation.


Asunto(s)
Metabolismo Energético , Estradiol , Hormona Folículo Estimulante , Ovariectomía , Ratas Wistar , Animales , Femenino , Metabolismo Energético/efectos de los fármacos , Ratas , Hormona Folículo Estimulante/metabolismo , Estradiol/farmacología , Composición Corporal/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Ovario/efectos de los fármacos , Ovario/metabolismo , Tejido Adiposo Blanco/metabolismo , Tejido Adiposo Blanco/efectos de los fármacos , Hígado/metabolismo , Hígado/efectos de los fármacos , Transcriptoma/efectos de los fármacos
9.
Microsc Res Tech ; 2024 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-38515433

RESUMEN

Skin cancer is a terrifying disorder that affects all individuals. Due to the significant increase in the rate of melanoma skin cancer, early detection of skin cancer is now more critical than ever before. Malignant melanoma is one of the most serious forms of skin cancer, and it is caused by abnormal melanocyte cell growth. In recent years, skin cancer predictive categorization has become more accurate and predictive due to multiple deep learning algorithms. Malignant melanoma is diagnosed using the Recurrent Convolution Neural Network-Long Short-Term Memory (RCNN-LSTM), which is one of the deep learning classification approaches. Using the International Skin Image Collection and the RCNN-LSTM, the data are categorized and analyzed to gain a better understanding of skin cancer. The method begins with data preprocessing, which prepares the dataset for classification. Additionally, the RCNN is employed to extract the features that are vital to the prediction process. The LSTM is accountable for the final step, classification. There are further factors to examine, such as the precision of 94.60%, the sensitivity of 95.67%, and the F1-score of 95.13%. Other benefits of the suggested study include shorter prediction durations of 95.314, 122.530, and 131.205 s and lower model loss of 0.25%, 0.19%, and 0.15% for input sizes 10, 15, and 20, respectively. Three datasets had a reduced categorization error of 5.11% and an accuracy of 95.42%. In comparison to previous approaches, the work discussed here produces superior outcomes. RESEARCH HIGHLIGHTS: Recurrent convolutional neural network (RCNN) deep learning approach for optimizing time prediction and error classification in early melanoma detection. It extracts a high number of specific features from the skin disease image, making the classification process easier and more accurate. To reduce classification errors in accurately detecting melanoma, context dependency is considered in this work. By accounting for context dependency, the deprivation state is avoided, preventing performance degradation in the model. To minimize melanoma detection model loss, a skin disease image augmentation or regularization process is performed in this work. This strategy improves the accuracy of the model when applied to fresh, previously unobserved data.

10.
J Biomed Mater Res B Appl Biomater ; 112(3): e35397, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38456309

RESUMEN

In this study, we have formulated a novel apatite bone cements derived from natural sources (i.e. eggshell and fishbone) with improved qualities that is, porosity, resorbability, biological activity, and so forth. The naturally-derived apatite bone cement (i.e. FBDEAp) was prepared by mixing hydroxyapatite (synthesized from fishbone) and tricalcium phosphate (synthesized from eggshell) as a solid phase with a liquid phase (a dilute acidic blend of cement binding accelerator and biopolymers like gelatin and chitosan) with polysorbate (as liquid porogen) to get a desired bone cement paste. The prepared cement paste sets within the clinically acceptable setting time (≤20 min), easily injectable (>85%) through hands and exhibits physiological pH stability (7.3-7.4). The pure apatite phased bone cement was confirmed by x-ray diffraction and Fourier transform infrared spectroscopy analyses. The FBDEAp bone cement possesses acceptable compressive strength (i.e. 5-7 MPa) within trabecular bone range and is resorbable up to 28% in simulated body fluid solution within 12 weeks of incubation at physiological conditions. The FBDEAp is macroporous in nature (average pore size ~50-400 µm) with interconnected pores verified by SEM and micro-CT analyses. The FBDEAp showed significantly increased MG63 cell viability (>125% after 72 h), cell adhesion, proliferation, and key osteogenic genes expression levels (up to 5-13 folds) compared to the synthetically derived, synthetic and eggshell derived as well as synthetic and fishbone derived bone cements. Thus, we strongly believe that our prepared FBDEAp bone cement can be used as potential trabecular bone substitute in orthopedics.


Asunto(s)
Sustitutos de Huesos , Quitosano , Apatitas/farmacología , Apatitas/química , Sustitutos de Huesos/química , Cementos para Huesos/farmacología , Cementos para Huesos/química , Fosfatos de Calcio/química , Durapatita , Quitosano/farmacología , Quitosano/química , Difracción de Rayos X , Fuerza Compresiva
11.
Phys Chem Chem Phys ; 26(14): 11140-11149, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38530754

RESUMEN

In recent years, hydrogen (H2) has become the most sought-after sustainable energy carrier by virtue of its high energy content and carbon-free emission. The practical implementation of hydrogen as an alternative fuel calls for an efficient and secure storage medium. Within this framework, we have investigated Li-grafted Si-doped γ-graphyne for H2 storage applications by implementing the cutting-edge density functional theory (DFT). A dynamically and thermally stable Si-doped γ-graphyne (SiG) monolayer is functionalized with Li metal atoms that augmented the hydrogen binding strength of the nanolayer by almost three times, owing to the polarization effect of the Li atoms. The Li metal atoms get adsorbed over the monolayer, allowing a binding energy of -2.73 eV that is greater than the Li cohesive energy (-1.63 eV), which eliminates the metal-metal clustering probability. The reliability of the Li-functionalized SiG monolayer (Li8SiG) at elevated temperature has been further substantiated by performing and analyzing ab initio molecular dynamics (AIMD) simulations at 400 K. It is noteworthy that a total of four H2 molecules are held up by each Li atom with an average adsorption energy of -0.32 eV and a maximum gravimetric capacity of 8.48 wt%, which remarkably follows the US-DOE parameters. Partial density of states and Hirshfeld charge analysis are utilized to recognize the interaction channel which reveals the Kubas and Niu-Rao-Jena-like bonding among the metal atoms and loaded hydrogen molecules. The hydrogen occupancy calculated at different temperatures and pressures indicates that hydrogen molecules can be reversibly stored over the Li8SiG system, and it is noted that adsorbed H2 begins to desorb at 280 K, with complete desorption at 400 K and 20 atm (or lower). AIMD simulations are further performed to authenticate the H2 desorption at various temperatures, which agrees well with the occupation number analysis. All the outcomes advocate for efficient reversible hydrogen storage over the proposed host material.

12.
Phys Chem Chem Phys ; 26(9): 7482-7491, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38354053

RESUMEN

A new four dimensional (4D) ab initio potential energy surface (PES) is generated for the collision of C4(3Σg-) with H2(1Σg), considering both molecules as rigid rotors. A supervised neural network model is created to augment the ab initio PES and to get the missing data points. Furthermore, space fixed expansion of the augmented PES is carried out using a least squares fit over two spherical harmonics terms, resulting in radial coefficients (λ1, λ2, and λ). The centre of symmetry in both C4 and H2 forces λ1 and λ2 to have even values, respectively. Moreover, the rotational states of C4 are only populated by odd levels due to its ground state triplet symmetry and the nuclear spin (I = 0) of 12C. The cross-sections and rate coefficients with para and ortho H2 partners are studied for various odd state transitions, where the rate coefficients of the ortho are 10-20% higher than those of the latter. The de-excitation rates obtained by the para H2 collisions are also compared to those of He and are found to be ∼1.7-2.8 times the He rates, across various order transitions. The simple scaling of He rates using a factor of 1.38 proves insufficient to describe para H2 rates. Therefore, these results show the importance of explicitly studying H2 as an important colliding partner, governing the kinetics of various rotational processes in the interstellar space.

13.
J Environ Manage ; 354: 120477, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38417362

RESUMEN

The Indian coastal waters are stressed due to a multitude of factors, such as the discharge of industrial effluents, urbanization (municipal sewage), agricultural runoff, and river discharge. The coastal waters along the eastern and western seaboard of India exhibit contrasting characteristics in terms of seasonality, the magnitude of river influx, circulation pattern, and degree of anthropogenic activity. Therefore, understanding these processes and forecasting their occurrence is highly necessary to secure the health of coastal waters, habitats, marine resources, and the safety of tourists. This article introduces an integrated buoy-satellite based Water Quality Nowcasting System (WQNS) to address the unique challenges of water quality monitoring in Indian coastal waters and to boost the regional blue economy. The Indian National Centre for Ocean Information Services (INCOIS) has launched a first-of-its-kind WQNS, and positioned the buoys at two important locations along the east (Visakhapatnam) and west (Kochi) coast of India, covering a range of environmental conditions and tourist-intensive zones. These buoys are equipped with different physical-biogeochemical sensors, data telemetry systems, and integration with satellite-based observations for real-time data transmission to land. The sensors onboard these buoys continuously measure 22 water quality parameters, including surface current (speed and direction), salinity, temperature, pH, dissolved oxygen, phycocyanin, phycoerythrin, Coloured Dissolved Organic Matter, chlorophyll-a, turbidity, dissolved methane, hydrocarbon (crude and refined), scattering, pCO2 (water and air), and inorganic macronutrients (nitrite, nitrate, ammonium, phosphate, silicate). This real-time data is transmitted to a central processing facility at INCOIS, and after necessary quality control, the data is disseminated through the INCOIS website. Preliminary results from the WQNS show promising outcomes, including the short-term changes in the water column oxic and hypoxic regimes within a day in coastal waters off Kochi during the monsoon period, whereas effluxing of high levels of CO2 into the atmosphere associated with the mixing of water, driven by local depression in the coastal waters off Visakhapatnam. The system has demonstrated its ability to detect changes in the water column properties due to episodic events and mesoscale processes. Additionally, it offers valuable data for research, management, and policy development related to coastal water quality.


Asunto(s)
Ecosistema , Calidad del Agua , India , Océanos y Mares , Naciones Unidas , Monitoreo del Ambiente , Agua de Mar/química
14.
Biol Reprod ; 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38302090
15.
bioRxiv ; 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38260651

RESUMEN

Most front-line tuberculosis drugs are ineffective against hypoxic non-replicating drug-tolerant Mycobacterium tuberculosis (Mtb) contributing to phenotypic antimicrobial resistance (AMR). This is largely due to the poor permeability in the thick and waxy cell wall of persister cells, leading to diminished drug accumulation and reduced drug-target engagement. Here, using an "arm-to-disarm" prodrug approach, we demonstrate that non-replicating Mtb persisters can be sensitized to Moxifloxacin (MXF), a front-line TB drug. We design and develop a series of nitroheteroaryl MXF prodrugs that are substrates for bacterial nitroreductases (NTR), a class of enzymes that are over-expressed in hypoxic Mtb. Enzymatic activation involves electron-transfer to the nitroheteroaryl compound followed by protonation via water that contributes to the rapid cleavage rate of the protective group by NTR to produce the active drug. Phenotypic and genotypic data are fully consistent with MXF-driven lethality of the prodrug in Mtb with the protective group being a relatively innocuous bystander. The prodrug increased intracellular concentrations of MXF than MXF alone and is more lethal than MXF in non-replicating persisters. Hence, arming drugs to improve permeability, accumulation and drug-target engagement is a new therapeutic paradigm to disarm phenotypic AMR.

16.
Sci Rep ; 14(1): 1543, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38233510

RESUMEN

An experimental study of three body abrasive wear behaviour of AZ31/15 vol.% Zirconium dioxide (ZrO2) reinforced composites prepared by stir casting has been carried out. Microstructural analysis of the developed composites was carried out and found out that the microstructure of the composites revealed a uniform distribution of ZrO2 particles with refinement in the grain size of the matrix from 70 to 20 µm. The alterations in the microstructure led to an enhancement in both hardness (68-104 HV) and tensile strength (156-236 MPa) due to Orowan strengthening, quench hardening effect and better bonding. Response surface methodology was applied to formulate the three-body abrasive wear test characteristics such as load, speed, and time. Three body abrasive test results were utilized to generate surface graphs for different combinations of wear test parameters revealed an increase in specific wear rate. The specific wear rate was observed to increase with increase in speed up to a certain level and then started to decrease. The lowest possible specific wear rate was obtained for an optimized load of 20 N and a speed of 190 ms-1. Scanning electron microscopic examination of wear-tested samples showed higher specific wear rate at higher loads with predominantly abrasion type material removal. In conclusion, this study makes a substantial contribution to the field by elucidating the complex relationships among microstructure, mechanical properties, and the three-body abrasive wear behavior of AZ31/ZrO2 composites. The determination of optimal wear conditions and the insights gained into wear mechanisms provide valuable information for designing materials, implementing engineering solutions, and advancing the creation of wear-resistant components across a range of industries.

17.
ACS Appl Mater Interfaces ; 16(5): 5857-5868, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38259199

RESUMEN

The selective carbon capture and utilization (CCU) as a one-carbon (C1) feedstock offers dual advantages for mitigating the rising atmospheric CO2 content and producing fine chemicals/fuels. In this context, herein, we report the application of a porous bipyridine-functionalized, pyrene-based covalent organic framework (Pybpy-COF) for the stable anchoring of catalytic Ag(0) nanoparticles (NPs) and its catalytic investigation for fixation of CO2 to commodity chemicals at ambient conditions. Notably, Ag@Pybpy-COF showed excellent catalytic activity for the carboxylation of various terminal alkynes to corresponding alkynyl carboxylic acids/phenylpropiolic acids via C-H bond activation under atmospheric pressure conditions. Besides, carboxylative cyclization of various propargylic amines with CO2 to generate 2-oxazolidinones, an important class of antibiotics, has also been achieved under mild conditions. This significant catalytic activity of Ag@Pybpy-COF with wide functional group tolerance is rendered by the presence of highly exposed, alkynophilic Ag(0) catalytic sites decorated on the pore walls of high surface area (787 m2 g-1) Pybpy-COF. Further, density functional theory calculations unveiled the detailed mechanistic path of the Ag@Pybpy-COF-catalyzed transformation of CO2 to alkynyl carboxylic acids and 2-oxazolidinones. Moreover, the catalyst showed high recyclability for several cycles of reuse without significant loss in its catalytic activity and structural rigidity. This work demonstrates the promising application of Pybpy-COF for stable anchoring of Ag NPs for successful transformation of CO2 to valuable commodity chemicals at ambient conditions.

18.
Chem Commun (Camb) ; 60(13): 1727-1730, 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38240148

RESUMEN

Hydrogen sulfide (H2S) and associated sulfur species known as persulfide or sulfane sulfur are considered among the first responders to oxidative stress. However, tools that reliably generate these species without any potentially toxic byproducts are limited, and even fewer report the generation of a persulfide. Here, using a latent fluorophore embedded with N-acetylcysteine persulfide, we report a new tool that is cleaved by esterase to produce a persulfide as well as a fluorescence reporter without any electrophilic byproducts. The rate of formation of the fluorescence reporter is nearly identical to the rate of formation of the persulfide suggesting that the use of this probe eliminates the need for secondary assays that report persulfide formation. Symptomatic with persulfide generation, the newly developed donor was able to protect chondrocyte cells from oxidative stress.


Asunto(s)
Esterasas , Sulfuro de Hidrógeno , Fluorescencia , Sulfuros , Azufre
19.
Biomater Adv ; 157: 213757, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38198999

RESUMEN

Full-thickness diabetic wounds are chronic injuries characterized by bleeding, excessive exude, and prolonged inflammation. Single-layer dressings fail to address their disturbed pathophysiology. Therefore, bilayer dressings with structural and compositional differences in each layer have gained attention. We hypothesized that natural polymer (alginate, curdlan, and agarose) based bilayer dressings with inherent healing properties could effectively resolve these issues. Hence, bilayer dressings were fabricated by electrospinning curdlan/agarose/ polyvinyl alcohol blend (top layer) on an alginate/agarose/polyvinyl alcohol-based lyophilized porous (bottom) layer. Ciprofloxacin was incorporated in both layers as a potential antibacterial drug. The bilayer dressing exhibited high swelling (~1300 %), biocompatibility (>90 % with NIH 3T3 and L929 mouse fibroblasts), and hemocompatibility (hemolysis <5 %). In vitro, scratch assay revealed a faster wound closure (~ 95-100 %) than control. Inhibition zone assay revealed antibacterial activity against Staphylococcus aureus and Escherichia coli. Real-time (in vitro) gene expression experiments performed using human THP-1 macrophages exhibited a significant increase in anti-inflammatory cytokines (4.51 fold in IL-10) and a decrease in pro-inflammatory cytokines (1.42 fold in IL-6) in comparison to lipopolysaccharide. Thus, fabricated dressings with high swelling, hemostatic, immunomodulatory, and antibacterial characteristics can serve as potential multifunctional and sustainable templates for healing full-thickness diabetic wounds.


Asunto(s)
Alginatos , Diabetes Mellitus , beta-Glucanos , Ratones , Animales , Humanos , Sefarosa , Alcohol Polivinílico , Porosidad , Antibacterianos/química , Diabetes Mellitus/tratamiento farmacológico , Vendajes , Citocinas
20.
Community Ment Health J ; 60(1): 131-147, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37679654

RESUMEN

The use of Lay Mental Health Workers (LMHWs) to tackle the treatment gap in low-resource settings is well established, and although they often receive training, the potential of proper supervision to improve outcomes remains untapped. Indeed, given the strain on expert resources, peer-supervision models based on supervisors' seniority of work experience have significant potential especially in relation to community knowledge and embedding of LMHWs. This study summarizes the evaluation of a pilot program for peer supervision on the basis of Social Cognitive Theories of Self-Efficacy for LMHWs in Kerala, India. Two experienced LMHWs worked as supervisors for a total of 12 LMHWs over the course of a year. These participants were subsequently interviewed to analyze their experiences in order to evaluate the potential of peer supervision and distil relevant information to improve future training of LMHWs. The findings include improved performance and emotional support for the participants.


Asunto(s)
Agentes Comunitarios de Salud , Salud Mental , Humanos , India , Agentes Comunitarios de Salud/educación
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