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1.
J Colloid Interface Sci ; 660: 780-791, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38277835

RESUMO

Highly soluble germanium oxide,an amorphous macroreticular form of germanium oxide, was used as a precursor for the deposition of GeS2on reduced graphene oxide (rGO) through a low-temperature, wet-chemistry process. Thermal treatment of the solid provided an ultrathin rGO - supported amorphous GeS2coating. The GeS2@rGO composite was tested as a lithium ion battery (LIB) anode. Leveraging the versatility of wet chemistry processing, we employed strategies initially developed for mitigating polysulfide shuttle effects in lithium-sulfur batteries to enhance anode performance. The anode exhibited exceptional stability, surpassing 1000 cycles, with charge capacities exceeding 1220 and 870 mAh.g-1 at rates of 2 and 5 A.g-1, respectively. Performance improvements were achieved by minimizing GeS2 grain size using the non-ionic surfactant Triton X-100 during synthesis and preventing polysulfide shuttle effects through a negatively charged thick glass fiber separator, fluoroethylene carbonate additive (FEC) in EC:DEC (ethylene carbonate: diethyl carbonate) solvent, and a polyacrylic acid (PAA) binder. These cumulative modifications more than tripled the charge capacity of the germanium sulfide LIB anode. Feasibility was further demonstrated through full cell studies using a LiCoO2 counter electrode.

2.
Chem Commun (Camb) ; 59(73): 10928-10931, 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37605935

RESUMO

By overcoming all conventional limitations associated with the synthesis of metalloid micro- and nanoparticles in aqueous media, we present a new one-step approach to the synthesis of highly crystalline metalloid hollow architectures. The liquid metal-mediated synthesis of Ge- and Sb-based hollow structures with satisfactory reaction kinetics at room temperature and normal pressure is presented.

3.
Carbohydr Polym ; 313: 120850, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37182950

RESUMO

Bacterial cellulose (BC) is a chemically pure, non-toxic, and non-pyrogenic natural polymer with high mechanical strength and a complex fibrillar porous structure. Due to these unique biological and physical properties, BC has been amply used in the food industry and, to a somewhat lesser extent, in medicine and cosmetology. To expand its application the BC structure can be modified. This review presented some recent developments in electrically conductive BC-based composites. The as-synthesized BC is an excellent dielectric. Conductive polymers, graphene oxide, nanoparticles and other materials are used to provide it with conductive properties. Conductive bacterial cellulose (CBC) is currently investigated in numerous areas including electrically conductive scaffolds for tissue regeneration, implantable and wearable biointerfaces, flexible batteries, sensors, EMI shielding composites. However, there are several issues to be addressed before CBC composites can enter the market, namely, composite mechanical strength reduction, porosity decrease, change in chemical characteristics. Some of them can be addressed both at the stage of synthesis, biologically, or by adding (nano)materials with the required properties to the BC structure. We propose several solutions to meet the challenges and suggest some promising BC applications.


Assuntos
Celulose , Nanopartículas , Celulose/química , Polímeros/química , Próteses e Implantes , Eletrônica
4.
NeuroRehabilitation ; 51(1): 1-22, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35527574

RESUMO

BACKGROUND: Stroke is the main reason for disabilities worldwide leading to motor dysfunction, spatial neglect and cognitive problems, aphasia, and other speech-language pathologies, reducing the life quality. To overcome disabilities, telerehabilitation (TR) has been recently introduced. OBJECTIVE: The aim of this review was to analyze current TR approaches for stroke patients' recovery. METHODS: We searched 6 online databases from January 2018 to October 2021, and included 70 research and review papers in the review. We analyzed TR of 995 individuals, which was delivered synchronously and asynchronously. RESULTS: Findings show TR is feasible improving motor function, cognition, speech, and language communication among stroke patients. However, the dose of TR sessions varied significantly. We identified the following limitations: lack of equipment, software, and space for home-based exercises, insufficient internet capacity and speed, unavailability to provide hands on guidance, low digital proficiency and education, high cognitive demand, small samples, data heterogeneity, and no economic evaluation. CONCLUSIONS: The review shows TR is superior or similar to conventional rehabilitation in clinical outcomes and is used as complementary therapy or as alternative treatments. More importantly, TR provides access to rehabilitation services of a large number of patients with immobility, living in remote areas, and during COVID-19 pandemic or similar events.


Assuntos
Afasia , COVID-19 , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Telerreabilitação , Afasia/reabilitação , Humanos , Pandemias
5.
Mikrochim Acta ; 188(5): 152, 2021 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-33813615

RESUMO

The analysis of compounds of the nitroguanidine family at trace level poses an analytical challenge. Nitroguanidine, 1-methyl-3-nitroguanidine, and 1-methyl-3-nitro-1-nitrosoguanidine, which are addressed in this article, have low lipophilicity, with log(Kow) equal to -0.89, - 0.84, and 0.68, respectively, and as such are not amenable for preconcentration from water. Liquid-liquid extraction and SPE fail to concentrate them from water and it is also not possible to extract them by ion exchange resin even after a pH change. Nitroguanidine and 1-methyl-3-nitroguanidine nitramines are explosives of growing use and thereby growing environmental concern due to lower detonation sensitivity compared to RDX. A sensitive method for the determination of nitroguanidine, 1-methyl-3-nitroguanidine, and 1-methyl-3-nitroso-1-nitroguanidine by reduction to the respective amines and subsequent hydrophobization by derivatization with 4-nitrobenzaldehyde followed by LC-ESI-MS analysis is described. Reduction by sodium borohydride using palladium modified graphitic carbon nitride (Pd/g-C3N4) provided improved sensitivity compared to the traditional palladium modified activated carbon due to the lower adsorption of the reduction products on the carbon nitride substrate. The limit of detection of the method was 10 ng L-1 for nitroguanidine, and repeated analyses of spiked effluents and contaminated spring water gave relative standard deviations of 8.8% and 6.5%, respectively. The findings illuminate the great promise of Pd/g-C3N4 as a reduction catalyst for the determination of challenging hydrophilic organic contaminants.

6.
ACS Appl Mater Interfaces ; 12(14): 16227-16235, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32167739

RESUMO

Microencapsulation of a carbon nanotube (CNT)-loaded paraffin phase change material, PCM in a poly(melamine-formaldehyde) shell, and the respective CNT-PCM gypsum composites is explored. Although a very low level (0.001-0.1 wt %) of intramicrocapsule loading of CNT dopant does not change the thermal conductivity of the solid, it increases the measured effusivity and thermal buffering performance during phase transition. The observed effusivity of 0.05 wt % CNT-doped PCM reaches 4000 W s-0.5 m-2 K-1, which is higher than the reported effusivity of alumina and alumina bricks and an order of magnitude larger than the solid, CNT-free PCM powder. The CNT dopant (0.015 wt %) in a 30 wt % PCM-plaster composite improved the effusivity by 60% compared to the CNT-free composite, whereas the addition of the same amount of CNTs to the bulk of the plaster does not improve either the effusivity or the thermal buffering performance of the composite. The thermal enhancement is ascribed to a CNT network formation within the paraffin core.

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