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1.
Chem Rec ; 24(1): e202300141, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37724006

RESUMEN

Electrical conductivity is very important property of nanomaterials for using wide range of applications especially energy applications. Metal-organic frameworks (MOFs) are notorious for their low electrical conductivity and less considered for usage in pristine forms. However, the advantages of high surface area, porosity and confined catalytic active sites motivated researchers to improve the conductivity of MOFs. Therefore, 2D electrical conductive MOFs (ECMOF) have been widely synthesized by developing the effective synthetic strategies. In this article, we have summarized the recent trends in developing the 2D ECMOFs, following the summary of potential applications in the various fields with future perspectives.

2.
Macromol Rapid Commun ; 43(7): e2100905, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35092115

RESUMEN

Creating nanosized pores in layered materials can increase the abundant active surface area and boost potential applications of energy storage devices. Herein, a unique synthetic strategy based on polyaniline (PANI) doped 2D cobalt-iron layered double hydroxide (CoFe-LDH/P) nanomaterials are designed, and the formation of pores at low temperature (80 °C) is developed. It is found that the optimized concentration of PANI creates the nanopores on the CoFe-LDH nanosheets among all other polymers. The well-ordered pores of CoFe-LDH/P allow the high accessibility of the redox-active sites and promote effective ion diffusion. The optimized CoFe-LDH/P2 cathode reveals a specific capacitance 1686 (1096 Cg-1 ) and 1200 Fg-1 (720 Cg-1 ) at 1 and 30 Ag-1 respectively, a high rate capability (71.2%), and a long cycle life (98% over 10 000 cycles) for supercapacitor applications. Charge storage analysis suggests that the CoFe-LDH/P2 electrode displays a capacitive-type storage mechanism (69% capacitive at 1 mV s-1 ). Moreover, an asymmetric aqueous supercapacitor (CoFe-LDH/P2//AC) is fabricated, delivering excellent energy density (75.9 Wh kg-1 at 1124 W kg-1 ) with outstanding stability (97.5%) over 10 000 cycles. This work opens a new avenue for designing porous 2D materials at low temperature for aqueous energy storage devices.


Asunto(s)
Cobalto , Hierro , Compuestos de Anilina/química , Cobalto/química , Hidróxidos
3.
Sensors (Basel) ; 19(7)2019 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-30987246

RESUMEN

Wireless Sensor Network (WSN) based smart homes are proving to be an ideal candidate to provide better healthcare facilities to elderly people in their living areas. Several currently proposed techniques have implementation and usage complexities (such as wearable devices and the charging of these devices) which make these proposed techniques less acceptable for elderly people, while the behavioral analysis based on visual techniques lacks privacy. In this paper, a context-aware accurate wellness determination (CAAWD) model for elderly people is presented, where behavior monitoring information is extracted by using simple sensor nodes attached to household objects and appliances for the analysis of daily, frequent behavior patterns of elderly people in a simple and non-obtrusive manner. A contextual data extraction algorithm (CDEA) is proposed for the generation of contextually comprehensive behavior-training instances for accurate wellness classification. The CDEA presents an activity's spatial-temporal information along with behavioral contextual correlation aspects (such as the object/appliance of usage and sub-activities of an activity) which are vital for accurate wellness analysis and determination. As a result, the classifier is trained in a more logical manner in the context of behavior parameters which are more relevant for wellness determination. The frequent behavioral patterns are classified using the lazy associative classifier (LAC) for wellness determination. The associative nature of LAC helps to integrate spatial-temporal and related contextual attributes (provided by CDEA) of elderly behavior to generate behavior-focused classification rules. Similarly, LAC provides high accuracy with less training time of the classifier, includes minimum-support behavior patterns, and selects highly accurate classification rules for the classification of a test instance. CAAWD further introduces the ability to contextually validate the authenticity of the already classified instance by taking behavioral contextual information (of the elderly person) from the caregiver. Due to the consideration of spatial-temporal behavior contextual attributes, the use of an efficient classifier, and the ability to contextually validate the classified instances, it has been observed that the CAAWD model out-performs currently proposed techniques in terms of accuracy, precision, and f-measure.


Asunto(s)
Actividades Cotidianas , Monitoreo Fisiológico , Dispositivos Electrónicos Vestibles , Tecnología Inalámbrica , Anciano , Algoritmos , Cuidadores , Humanos
4.
Adv Sci (Weinh) ; 11(17): e2309163, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38425147

RESUMEN

Tuning the crystal phase of alloy nanocrystals (NCs) offers an alternative way to improve their electrocatalytic performance, but, how heterometals diffuse and form ordered-phase remains unclear. Herein, for the first time, the mechanism for forming tetrametallic ordered-phase nanoplates (NPLs) is unraveled. The observations reveal that the intermetallic ordered-phase nucleates through crystallinity alteration of the seeds and then propagates by reentrant grooves. Notably, the reentrant grooves act as intermediate NCs for ordered-phase, eventually forming intermetallic PdCuIrCo NPLs. These NPLs substantially outperform for oxygen evolution reaction (221 mV at 10 mA cm-2) and hydrogen evolution reaction (19 mV at 10 mA cm-2) compared to commercial Ir/C and Pd/C catalysts in acidic media. For OER at 1.53 V versus RHE, the PdCuIrCo/C exhibits an enhanced mass activity of 9.8 A mg-1 Pd+Ir (about ten times higher) than Ir/C. For HER at -0. 2 V versus RHE, PdCuIrCo/C shows a remarkable mass activity of 1.06 A mg-1 Pd+Ir, which is three-fold relative to Pd/C. These improvements can be ascribed to the intermetallic ordered-structure with high-valence Ir sites and tensile-strain. This approach enabled the realization of a previously unobserved mechanism for ordered-phase NCs. Therefore, this strategy of making ordered-phase NPLs can be used in diverse heterogeneous catalysis.

5.
Polymers (Basel) ; 15(13)2023 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-37447513

RESUMEN

Novel ultrafiltration (UF) polymer membranes were prepared to enhance the antifouling features and filtration performance. Several ultrafiltration polymer membranes were prepared by incorporating different concentrations of water-soluble cationic poly [2-(dimethyl amino) ethyl methacrylate] (PDMAEMA) into a homogenous casting solution of polyethersulfone (PES). After adding PDMAEMA, the effects on morphology, hydrophilicity, thermal stability, mechanical strength, antifouling characteristics, and filtration performance of these altered blended membranes were investigated. It was observed that increasing the quantity of PDMAEMA in PES membranes in turn enhanced surface energy, hydrophilicity, and porosity of the membranes. These new modified PES membranes, after the addition of PDMAEMA, showed better filtration performance by having increased water flux and a higher flux recovery ratio (FRR%) when compared with neat PES membranes. For the PES/PDMAEMA membrane, pure water flux with 3.0 wt.% PDMAEMA and 0.2 MPa pressure was observed as (330.39 L·m-2·h-1), which is much higher than that of the neat PES membrane with the value of (163.158 L·m-2·h-1) under the same conditions. Furthermore, the inclusion of PDMAEMA enhanced the antifouling capabilities of PES membranes. The total fouling ratio (TFR) of the fabricated PES/PDMAEMA membranes with 3.0 wt.% PDMAEMA at 0.2 MPa applied pressure was 36 percent, compared to 64.9 percent for PES membranes.

6.
Polymers (Basel) ; 15(15)2023 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-37571177

RESUMEN

This study describes the preparation and evaluation of phenol-furfural resin (PFR) from bagasse and its nanocomposites for electrically conductive adhesive (ECA) application. PFR was prepared with furfural extracted from bagasse using a modified acid digestion method. Three different formulations of PFR nanocomposites with conductive nanoparticles, i.e., PFR-silver, PFR-graphite, and PFR-silver + graphite, were prepared using 20, 40, and 60 w/w% of fillers via the impregnation method. The resultant products were characterized using FT-IR, SEM, EDS, and XRD spectroscopy. Electrical conductivity was measured using a four-probe technique, while band gap was calculated via Tauc plots. The results exhibited a significant rise in electrical conductivity of insulating virgin PFR from 2.6 × 10-4 Scm-1 to 8.2 × 10-1 Scm-1 with a 40 and 20 w/w% blend of Ag and graphite in PFR. This synergism was exhibited because graphite and Ag NPs supply excellent junctions for building networks. Both tend to coalesce due to van der Waals forces and high surface energies. Therefore, conductive pathway numbers can be increased, and the contact area can be effectively enlarged. This ternary composite exhibited the lowest bandgap energy value, i.e., 3.1 eV. Thermogravimetric temperature values T0 and Tdeg were increased up to 120 °C and 484 °C, respectively, showing a significant increase in thermal stability. Therefore, the resultant nanocomposite material has good potential to be employed as an ECA in the electronic industry.

7.
ACS Omega ; 8(2): 2173-2182, 2023 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-36687058

RESUMEN

In the present work, TiO2/g-C3N4 nanocomposites were synthesized by using highly crystalline TiO2 nanorods/rice (NRs) and various percentages of g-C3N4 via a facile, scalable, and inexpensive pyrolysis method. The synthesized nanocomposites were characterized by various techniques, e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N2 adsorption and desorption analysis (BET), Fourier transform infrared spectroscopy (FTIR), UV-vis diffuse reflectance spectroscopy (DRS), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). It was found that biodiesel production by the esterification reaction can be remarkably enhanced by coupling TiO2 with g-C3N4; hereby, it was observed that with increasing percentage of g-C3N4 from 5 to 10 and 15% with respect to TiO2 NRs, the photocatalytic activity rose and the maximum photocatalytic activity with 97% conversion was observed for NC-3, i.e., 15% g-C3N4/TiO2. Moreover, the photoactivity of pristine TiO2 NR aggregates was contrasted with their nanoparticle morphology and was estimated to be slightly better. When applied for photocatalytic Congo red dye degradation, this sample showed a 91% degradation efficiency using only a very small amount of the catalyst. The high catalytic efficiency is attributed to the narrow band gap, exceptionally high surface area, and efficient charge separation properties of the prepared catalysts.

8.
iScience ; 26(8): 107304, 2023 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-37539034

RESUMEN

Sensitivity and linearity are two crucial indices to assess the sensing capability of pressure sensors; unfortunately, the two mutually exclusive parameters usually result in limited applications. Although a series of microengineering strategies including micropatterned, multilayered, and porous approach have been provided in detail, the conflict between the two parameters still continues. Here, we present an efficient strategy to resolve this contradiction via modulus difference-induced embedding deformation. Both the microscopic observation and finite element simulation results confirm the embedding deformation behavior ascribed to the elastic modulus difference between soft electrode and rigid microstructures. The iontronic pressure sensor with high sensitivity (35 kPa-1) and wide linear response range (0-250 kPa) is further fabricated and demonstrates the potential applications in monitoring of high-fidelity pulse waveforms and human motion. This work provides an alternative strategy to guide targeted design of all-around and comprehensive pressure sensor.

9.
Sci Rep ; 13(1): 4572, 2023 03 20.
Artículo en Inglés | MEDLINE | ID: mdl-36941313

RESUMEN

This article presents that acrylate copolymers are the potential candidate against the adsorption of bovine serum albumin (BSA). A series of copolymers poly(methyl methacrylate) (pMMA), poly(3-sulfopropyl methacrylate-co-methyl methacrylate) p(SPMA-co-MMA), and poly(dimethylaminoethyl methacrylate-co-methyl methacrylate) p(DMAEMA-co-MMA) were synthesized via free radical polymerization. These amphiphilic copolymers are thermally stable with a glass transition temperature (Tg) 50-120 °C and observed the impact of surface charge on amphiphilic copolymers to control interactions with the bovine serum albumin (BSA). These copolymers pMD1 and pMS1 have surface charges, - 56.6 and - 72.6 mV at pH 7.4 in PBS buffer solution that controls the adsorption capacity of bovine serum albumin (BSA) on polymers surface. Atomic force microscopy (AFM) analysis showed minimum roughness of 0.324 nm and 0.474 nm for pMS1 and pMD1. Kinetic studies for BSA adsorption on these amphiphilic copolymers showed the best fitting of the pseudo-first-order model that showed physisorption and attained at 25 °C and pH 7.4 within 24 h.


Asunto(s)
Polímeros , Albúmina Sérica Bovina , Cinética , Polimetil Metacrilato , Acrilatos , Metacrilatos
10.
Small Methods ; : e2301490, 2023 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-38063782

RESUMEN

Defects in the crystal structure of nanomaterials are important for their diverse applications. As, defects in 2D framework allow surface confinement effects, efficient molecular accessibility, high surface-area to volume-ratio and lead to higher catalytic activity, but it is challenging to expose defects of specific metal on the surface of 2D alloy and find the correlation between defective structure and electrocatalytic properties with atomic precision. Herein, the work paves the way for the controlled synthesis of ultrathin porous Ir-Cu nanosheets (NSs) with selectively iridium (Ir) rich defects to boost their performance for acidic oxygen evolution reaction (OER). X-ray absorption spectroscopy reveals that the oxidized states of Ir in defects of porous NSs significantly impact the electronic structure and decline the energy barrier. As a result, porous Ir-Cu/C NSs deliver improved OER activity with an overpotential of 237 mV for reaching 10 mA cm-2 and exhibit significantly higher mass activity than benchmark Ir/C under acidic conditions. Therefore, the present work highlights the concept of constructing a selective noble metal defect-rich open structure for catalytic applications.

11.
Sci Rep ; 12(1): 14936, 2022 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-36056200

RESUMEN

Partition coefficients for storage lipid-water (logKlw) and phospholipid-water (logKpw) phases are key parameters to understand the bioaccumulation and toxicity of organic contaminants. However, the published experimental databases of these properties are dwarfs and current estimation approaches are cumbersome. Here, we present partition models that exploit the correlations of logKlw, and of logKpw with the linear combinations of the octanol-water partition coefficient (logKow) and the dimensionless Henry's law constant (air-water partition coefficient, logKaw). The calibrated partition models successfully describe the variations in logKlw data (n = 305, R2 = 0.971, root-mean-square-error (rmse) = 0.375), and in logKpw data (n = 131, R2 = 0.953, rmse = 0.413). With the inputs of logKow and logKaw estimated from the U.S. EPA's EPI Suite, our models of logKlw and logKpw have exhibited rmse = 0.52 with respect to experimental values indicating suitability of these models for inclusion in the EPI Suite. Our models perform similar to or better than the previously reported models such as one parameter partition models, Abraham solvation models, and models based on quantum-chemical calculations. Taken together, our models are robust, easy-to-use, and provide insight into variations of logKlw and logKpw in terms of hydrophobicity and volatility trait of chemicals.


Asunto(s)
Compuestos Orgánicos , Agua , Octanoles/química , Compuestos Orgánicos/química , Agua/química
12.
Polymers (Basel) ; 14(13)2022 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-35808585

RESUMEN

The fouling of surfaces such as textiles is a major health challenge, and there is a continuous effort to develop materials and processes to overcome it. In consideration of this, this study regards the development of antifouling functional nanoencapsulated finishing for the cotton textile fabric by employing a layer-by-layer dip coating technique. Antifouling textile finishing was formulated by inducing the nanoencapsulation of the antifouling functional group inside the hydrophobic polymeric shell. Cotton fabric was taken as a substrate to incorporate antibacterial functionality by alternatively fabricating multilayers of antifouling polymeric formulation (APF) and polyelectrolyte solution. The surface morphology of nanoencapsulated finished textile fabric was characterized through scanning electron microscopy to confirm the uniform distribution of nanoparticles on the cotton textile fabric. Optical profilometry and atomic force microscopy studies indicated increased surface roughness in the coated textile substrate as compared to the uncoated textile. The surface thickness of the fabricated textile increased with the number of deposited bilayers on the textile substrate. Surface hydrophobicity increased with number of coating bilayers with θ values of x for single layer, up to y for 20 bilayers. The antibacterial activity of the uncoated and layer-by-layer coated finished textile was also evaluated. It was significant and exhibited a significant zone of inhibition against microbial strains Gram-positive S. aureus and Gram-negative E. coli. The bilayer coating exhibited water repellency, hydrophobicity, and antibacterial activity. Thus, the fabricated textile could be highly useful for many industrial and biomedical applications.

13.
Polymers (Basel) ; 14(11)2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35683936

RESUMEN

Membrane fouling is a continued critical challenge for ultrafiltration membranes performance. In this work, polyether sulfone (PES) ultrafiltration (UF) membranes were fabricated via phase-inversion method by incorporating varying concentrations of APTMS modified activated carbon (mAC). The mAC was thoroughly characterized and the fabricated membranes were studied for their surface morphology, functional groups, contact angle, water retention, swelling (%) porosity, and water flux. The hydrophilicity of mAC membranes also resulted in lower contact angle and higher values of porosity, roughness, water retention as well as water flux. Also, the membranes incorporated with mAC exhibited antibacterial performance against model test strains of gram-negative Ecoil and gram-positive S. aureus. The antifouling studies based on bovine serum albumin protein (BSA) solution filtration showed that mAC membranes have better BSA flux. The higher flux and antifouling characteristics of the mAC membranes were attributed to the electrostatic repulsion of the BSA protein from the unique functional properties of AC and network structure of APTMS. The novel mAC ultrafiltration membranes developed and studied in present work can provide higher flux and less BSA rejection thus can find antifouling applications for the isolation and concentration of proteins and macromolecules.

14.
Int J Biol Macromol ; 222(Pt A): 887-901, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36179868

RESUMEN

The evolution and development of solid-matrix are considered a backbone for supporting and stabilizing of metal nanoparticles (NPs) and are the soul of the catalytic system. In the current study, the alginate-starch microsphere (Alg-St) was cross-linked using CaCl2 as a cross-linker. In addition, the Alg-St microsphere was blended with different percentages of activated carbon (AC). The microspheres adsorbed Cu+2 was reduced to zero-valent copper NPs through NaBH4 and used as a dip-catalyst. The supported Cu NPs cum NaBH4 system was used as dip-catalyst for the hydrogenation of 4-nitrophenol (4NP), 2-nitroanilline (2NA), and degradation of methylene blue (MB) and Congo red (CR) dyes. Among the different kinetics models, the experimental data were well-fitted in the zero-order kinetic model. Moreover pH, and recyclability were studied for 4NP, where the best activity was achieved at pH 7.0 for 4NP. No leaching was observed after 3rd cycle in the catalyst.


Asunto(s)
Colorantes , Nanopartículas del Metal , Carbón Orgánico , Microesferas , Hidrogenación , Alginatos , Almidón , Catálisis
15.
Front Chem ; 10: 996560, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36277339

RESUMEN

Electrochemical water splitting has enticed fascinating consideration as a key conduit for the advancement of renewable energy systems. Fabricating adequate electrocatalysts for water splitting is fervently preferred to curtail their overpotentials and hasten practical utilizations. In this work, a series of Ce-MOF, GO@Ce-MOF, calcinated Ce-MOF, and calcinated GO@Ce-MOF were synthesized and used as high-proficient electrocatalysts for the oxygen evolution reaction. The physicochemical characteristics of the prepared samples were measured by diverse analytical techniques including SEM, HRTEM, FTIR, BET, XPS, XRD, and EDX. All materials underwent cyclic voltammetry tests and were evaluated by electrochemical impedance spectroscopy and oxygen evolution reaction. Ce-MOF, GO@Ce-MOF, calcinated Ce-MOF, and calcinated GO@Ce-MOF have remarkable properties such as enhanced specific surface area, improved catalytic performance, and outstanding permanency in the alkaline solution (KOH). These factors upsurge ECSA and intensify the OER performance of the prepared materials. More exposed surface active-sites present in calcinated GO@Ce-MOF could be the logic for superior electrocatalytic activity. Chronoamperometry of the catalyst for 15°h divulges long-term stability of Ce-MOF during OER. Impedance measurements indicate higher conductivity of synthesized catalysts, facilitating the charge transfer reaction during electrochemical water splitting. This study will open up a new itinerary for conspiring highly ordered MOF-based surface active resources for distinct electrochemical energy applications.

16.
Wien Klin Wochenschr ; 133(13-14): 695-702, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32945946

RESUMEN

BACKGROUND: Pakistan has a nationwide expanded program on immunization (EPI), yet vaccination coverage in Pakistan is quite low. Recently, an analytical model has been proposed to improve the coverage by identifying children who are most likely to miss any of the vaccines included in the immunization schedule, known as defaulters; however, a number of limitations remain unresolved in the previously proposed model. Firstly, it only classified children into two stages: defaulters and non-defaulters, considering all children at high risk of defaulting even if only one dose is missed. Secondly, there was no categorisation of high and low coverage areas for prioritised vaccination. The aim of this study was to propose a prediction framework for the accurate identification of defaulters. METHODS: We have utilised a sample dataset extracted from the Pakistan Demographic and Health Survey (PDHS, 2017-2018). This contained 7153 data records with 19 demographic and socioeconomic attributes, which were used for defaulter prediction and the identification of association rules to understand the relation between demographics of the child and the vaccination status. RESULTS: Using a multilayer perceptron (MLP) classifier, the proposed model achieved 98% accuracy and 0.994 for the area under the curve (AUC), to correctly identify the children who are likely to default from immunization series at different risk stages. CONCLUSION: The proposed framework in this study is a step forward towards a data-driven approach and provides a set of machine learning techniques to utilise predictive analytics. Hence, this can reinforce immunization programs by expediting targeted action to reduce drop-outs.


Asunto(s)
Programas de Inmunización , Cobertura de Vacunación , Niño , Humanos , Inmunización , Esquemas de Inmunización , Lactante , Pakistán , Vacunación
17.
Nanoscale ; 13(37): 15804-15811, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34528989

RESUMEN

Iron and nitrogen codoped carbons (Fe-N-C) have emerged as promising noble-metal-free catalysts for the oxygen reduction reaction (ORR). However, delicate control over their structure to enhance the catalytic efficiency is still challenging. Herein, we presented the synthesis of novel ionic-liquid (IL) derived nitrogen and iron co-doped carbon nanotube (CNT) based core-sheath nanostructures that can contribute to solving these challenges associated with the ORR. These nanostructures are synthesized by the adsorption of heteroatom containing ILs on the walls of CNTs followed by carbonization. The advantage of using an IL as a nitrogen source is that the obtained catalyst has a high level of N doping and a high surface area. Electrochemical characterization revealed that the N and Fe codoped CNT based core-sheath nanostructures exhibited superior catalytic activities toward the ORR under both alkaline and acidic conditions. Particularly in alkaline solution, the CNT/Fe-N-C catalysts showed better ORR activity compared to the commercial Pt/C catalyst. We suggest that the excellent electrocatalytic performance of CNT/Fe-N-C catalysts is attributed to: (i) the synergistic effect, which provides more catalytic FeNx sites for the ORR, due to the Fe and N co-doping and (ii) the high surface area and excellent electron transfer rate arising from the IL-derived core-sheath structure.

18.
Polymers (Basel) ; 13(2)2021 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-33435345

RESUMEN

Amphiphilic copolymers are recognized as important biomaterials and used as antibacterial agents due to their effective inhibition of bacterial growth. In current study, the amphiphilic copolymers of P(DMAEMA-co-MMA) were synthesized using free radical polymerization by varying the concentrations of hydrophilic monomer 2-dimethylamino ethylmethacrylate (DMAEMA) and hydrophobic monomer methyl methacrylate (MMA) having PDI value of 1.65-1.93. The DMAEMA monomer, through ternary amine with antibacterial property optimized copolymers, P(DMAEMA-co-MMA), compositions to control biofilm adhesion. Antibacterial activity of synthesized copolymers was elucidated against Gram-positive Staphylococcus aureus (ATCC 6538) and Gram-negative Escherchia coli (ATCC 8739) by disk diffusion method, and zones of inhibition were measured. The desired composition that was PDM1 copolymer had shown good zones of inhibition i.e., 19 ± 0.33 mm and 20 ± 0.33 mm for E. coli and S. aureus respectively. The PDM1 and PDM2 have exhibited significant control over bacterial biofilm adhesion as tested by six well plate method. SEM study of bacterial biofilm formation has illustrated that these copolymers act in a similar fashion like cationic biocide. These compositions viz. PDM1 and PDM2, may be useful in development of bioreactors, sensors, surgical equipment and drug delivery devices.

19.
Polymers (Basel) ; 13(13)2021 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-34209144

RESUMEN

The objective of the present study was to achieve the successful encapsulation of a therapeutic agent to achieve antifouling functionality regarding biomedical applications. Considering nanotechnology, drug-loaded polycaprolactone (PCL)-based nanoparticles were prepared using a nano-precipitation technique by optimizing various process parameters. The resultant nano-formulations were investigated for in vitro drug release and antifouling applications. The prepared particles were characterized in terms of surface morphology and surface properties. Optimized blank and drug-loaded nanoparticles had an average size of 200 nm and 216 nm, respectively, with associated charges of -16.8 mV and -11.2 mV. Studies of the in vitro release of drug were carried out, which showed sustained release at two different pH, 5.5 and 7.4 Antifouling activity was observed against two bacterial strains, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The zone of inhibition of the optimized polymeric drug-loaded nanoparticle F-25 against both strains were compared with the pure drug. The gradual pH-responsive release of antibiotics from the biodegradable polymeric nanoparticles could significantly increase the efficiency and pharmacokinetics of the drug as compared to the pure drug. The acquired data significantly noted that the resultant nano-encapsulation of antifouling functionality could be a promising candidate for topical drug delivery systems and skin applications.

20.
Polymers (Basel) ; 13(9)2021 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-33926003

RESUMEN

The scope of silicone rubber (SiR) is confined due to the deprivation of its dielectric propertiesupon exposure to various ambient stresses. The aim of this research is to develop silicone rubber-based composites by employing inorganic oxide fillers for improved dielectric and high voltage insulation properties for widening its scope in the field of electrical appliances. This study reports the preparation of different composites of silicone rubber with varying concentrations of micro and nano-silica fillers. The dielectric propertytrends of these as-prepared neat and impregnated samples were examined via an indigenously developed weathering chamber capable of applying multiple stresses of acid rain, heat, humidity, UVA radiation, and salt fog. Dielectric constant values were measured before and after applying stresses. Upon applying stresses, a periodic decline in dielectric constant was observed. Improved dielectric properties were obtained by adding micro and nano-silica as fillers. A nano silica-incorporated silicone rubber product exhibited good potential for dual applications as dielectric and high voltage insulation.

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