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1.
Reprod Domest Anim ; 59(4): e14562, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38591843

RESUMO

Melatonin is an intracellular antioxidant of sperm membrane that protects the cells from lipid peroxidation. Yet, its role as an antioxidant on semen quality of buffalo bulls is still obscure. The present study was undertaken to assess the effect of exogenous melatonin implant (18 mg/50 kg bodyweight) on post-thaw sperm characteristics, oxidative stress, endocrinological profiles and fertility of buffalo bulls. Six apparently healthy breeding Murrah buffalo bulls were randomly selected at bull farm, Guru Angad Dev Veterinary and Animal Sciences University for the present study and divided into two groups viz. control (n = 3) and melatonin implanted group (n = 3). A total of 120 ejaculates were collected from bulls of both groups (n = 60 each) throughout the study period. Most beneficial effects of melatonin implants were observed during post-implantation period. The percentages of post-thaw sperm total and progressive motility, viability and mitochondrial membrane potential were higher (p < .05) in melatonin implanted buffalo bulls compared to controls during post-implantation period. Following melatonin implantation, MDA production in post-thaw semen was lower (p < .05) in melatonin implanted group than in control group. Plasma melatonin and testosterone concentrations were higher (p < .05) in buffalo bulls implanted with melatonin as compared to their control counterparts. No differences (p > .05) in plasma LH concentrations were observed in both groups. First service pregnancy rate was 43.3% using semen of melatonin implanted bulls and 30.0% with semen of controls (p > .05). Thus, melatonin was able to protect sperm membrane against oxidative damage and improve post-thaw semen quality, thereby resulting in higher fertilizing potential of spermatozoa.


Assuntos
Bison , Melatonina , Preservação do Sêmen , Humanos , Gravidez , Feminino , Masculino , Animais , Bovinos , Análise do Sêmen/veterinária , Sêmen , Búfalos , Melatonina/farmacologia , Antioxidantes/farmacologia , Motilidade dos Espermatozoides , Criopreservação/veterinária , Criopreservação/métodos , Preservação do Sêmen/veterinária , Preservação do Sêmen/métodos , Espermatozoides
2.
J Orthop ; 37: 15-21, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36974098

RESUMO

Background: Various operative procedures have been described for the treatment of traumatic paraplegia caused by unstable thoracolumbar fractures. We prospectively evaluated interbody fusion (IBF) with SS-PSF in these cases with regard to clinico-radiological outcome with the objectives: (1) Does IBF and short segment pedicle screw fixation (SS-PSF) prevent progression of kyphotic angle after surgery? (2) Can this procedure be safely performed in the setting of acute trauma?. Methods: Sixteen patients suffering from traumatic paraplegia caused by acute unstable thoracolumbar fractures were enrolled prospectively and underwent IBF with SS-PSF. They were evaluated for magnitude of shortening in spine, progression of kyphotic angle, and neurological improvement by American spinal injury association scale (ASIA). Results: Out of total sixteen, 14 patients were ASIA grade A and 2 were grade C, at the time of presentation. Thirteen out of these 14 remained grade A and one improved to B. Both the patients who had grade C involvement at the time of presentation improved to grade D at one-year follow-up. The mean blood loss was 750 ml (range; 650 ml-1150 ml). Mean kyphotic angle decreased from 20.6° (range; 13° to 37°) preoperatively to 6.2° (range; 3° to 10°) at postoperative day 2 (p = 0.002). Its mean value after 6 months was 6.5° (range; 3° to 11°). The procedure resulted in mean spinal column shortening of 18 mm (range; 16 mm-22 mm) in the spinal column. All the patients achieved bony union by a mean duration of 3.9 months (range; 3 months-6 months). Conclusions: IBF with SS-PSF has the shortest possible instrumented construct for thoracolumbar junction fusion done by posterior approach. The interbody fusion for unstable thoracolumbar junction fractures prevents the progression of kyphotic angle post-operatively. Level of evidence: Level 4.

3.
Cryobiology ; 107: 1-12, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35850230

RESUMO

Sodium Dodecyl Sulphate (SDS), N-Octyl ß-D Glucopyranoside (NOG), 4-Methoxy Phenyl ß-D Glucopyranoside (4-MPG) as ice recrystallization inhibitors were added to Tris Egg Yolk Glycerol (TEYG) semen extender for cryopreservation of semen of buffalo bulls. Post-thaw sperm motion and viability traits were evaluated. Pilot study involved six semen ejaculates (2 ejaculates/bull, from three bulls); second experiment was conducted using twenty seven semen ejaculates (9 ejaculates/bull, from 3 bulls) and in third experiment three semen ejaculates (one bull) were used. Eight concentrations of SDS (2, 1, 0.5, 0.25, 0.15, 0.125, 0.0625 and 0.0312%), twelve concentrations of NOG (33, 22, 11, 5.5, 2.5, 0.75, 0.5, 0.25, 0.125, 0.0625, 0.03125 and 0.0156 mM), and, eleven concentrations of 4-MPG (220, 165, 110, 55, 50, 25, 12.5, 6.25, 3.125, 1.56 and 0.78 mM) were supplemented in TEYG semen extender to evaluate the post-thaw sperm motility and viability traits. Computer Assisted Sperm Analysis (CASA) was used to measure the kinetic and functional parameters for sperm motion traits, Hypo Osmotic Swelling Test (HOST) for sperm plasma membrane integrity, Eosin Nigrosin staining for viability and Rose Bengal staining for sperm abnormalities for all the experiments except for pilot study where only Total Motility (TM) and Rapid Progressive Motility (RP) were evaluated. Three freezing protocols; i) Normal P24 (freezing rate of -30 °C min-1 from 4 °C to -15 °C; -40 °C min-1 from -15 °C to -60 °C; and -50 °C min-1 from -60 °C to -140 °C; and then plunged in liquid Nitrogen at -196 °C); ii) Moderate P25 (freezing rate of -30 °C min-1 from 4 °C to -15 °C; -50 °C min-1 from -15 °C to -60 °C; and -50 °C min-1 from -60 °C to -140 °C; and then plunged in liquid Nitrogen at -196 °C); and iii) Rapid P26 (freezing rate of -30 °C min-1 from 4 °C to -15 °C; -60 °C min-1 from -15 °C to -60 °C; and -50 °C min-1 from -60 °C to -140 °C; and then plunged in liquid Nitrogen at -196 °C) were evaluated using SDS 0.125% in TEYG semen extender. SDS ≤0.125%, NOG ≤0.0625 mM and 4-MPG ≤ 3.125 mM in TEYG buffalo semen extender improved significantly (p < .05) the kinetic and functional parameters as compared to the other Ice Recrystallization Inhibitors (IRIs) concentrations used for cryopreservation of buffalo bull semen in the pilot study. SDS 0.125% supplementation was the best IRI among all which resulted in improved kinetic and functional parameters of bull semen in second experiment. Conclusion was drawn that buffalo bull semen cryopreservation using sodium dodecyl sulphate, 0.125% as IRI in TEYG semen extender along with freezing protocol P 25 revealed optimum kinetic and functional parameters for post-thaw spermatozoa.


Assuntos
Búfalos , Preservação do Sêmen , Animais , Criopreservação/métodos , Crioprotetores/farmacologia , Gelo , Masculino , Nitrogênio/farmacologia , Projetos Piloto , Sêmen , Preservação do Sêmen/métodos , Preservação do Sêmen/veterinária , Dodecilsulfato de Sódio/farmacologia , Motilidade dos Espermatozoides , Espermatozoides
4.
Cryobiology ; 106: 102-112, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35278460

RESUMO

Graphene oxide (GO) greatly suppresses the growth and recrystallization by curving the hexagonal shape of ice crystals. Study was conducted to evaluate effect of GO as cryoprotectant in semen extender for augmenting sperm viability in dairy (cattle and buffalo) animals. In experiment one, semen was extended with TRIS Egg Yolk Glycerol (TEYG) extender supplemented with different concentrations of GO: 0.0125, 0.25, 0.5, 0.1 and 0.2 mg ml-1. Freezing of semen samples was conducted at 30 °C min-1 from temperature drop from 4 °C to -15 °C and -15 °C to - 60 °C followed by 50 °C min-1 from - 60 °C to -140 °C, and the semen straws were plunged in liquid nitrogen. Second experiment evaluated the performance of TEYG extender supplemented with combinations of GO (G05 as 0.05 and G10 as 0.1 mg ml-1) and glycerol (T48 as 4.8 and T64 as 6.4%) in four groups as G05T48, G05T64, G10T48 and G10T64. Freezing rates of 30 °C min-1[Protocol (PRT) I], 40 °C min-1 (PRT II) and 50 °C min-1 (PRT III) in the critical temperature fall zone of -15 °C to -60 °C were evaluated for semen extender supplemented with glycerol 6.4% and GO 0.05 mg ml-1 in the third experiment. Cattle (n = 3) and buffalo (n = 3) bulls were chosen for the study taking six ejaculates per bull per treatment. Post-thaw sperm motility, membrane integrity, viability and abnormalities were observed by means of CASA, Hypo-osmotic swelling test (HOST), Eosin-Nigrosin stain and Rose Bengal stain procedures, respectively. Post-thaw total motility (TM), progressive motility (PM), VCL, VSL, VAP, HOST response and viability increased significantly in extender with GO concentrations of 0.1 and 0.05 mg ml-1 as compared to control. Per cent abnormalities were significantly (p < .05) lower in group with GO 0.025 and 0.0125 mg ml-1 as compared to control. Results from the second experiment showed higher post-thaw TM, PM, VCL, VAP, VSL, HOST response, viability increased significantly (p < .05) in G05T64 and G05T48 as compared to G10T64. Sperm abnormalities did not vary among the groups as compared to control for cattle spermatozoa. In the third experiment post-thaw TM, PM, VCL, VSL, VAP, HOS response and sperm viability increased significantly (p < .05) in PRT III as compared to PRT I for buffalo and cattle spermatozoa. Sperm abnormalities were significantly (p < .05) lower in PRT II and PRT III as compared to PRT I for buffalo, whereas, lower in PRT II as compared to PRTI for cattle spermatozoa. GO as cryoprotectant when added to semen extender at the rate of 0.05 and 0.1 mg ml-1, resulted in better plasma membrane function and viability. Glycerol concentration below 6.4% in buffalo semen extender reduced post-thaw quality of sperm even when GO was added to the extender. Higher freezing rate of 50 °C min-1 in the critical temperature fall zone of -15 to -60 °C perform better than the freezing rate of 30 °C min-1. It is concluded that TEYG extender having glycerol 6.4% and GO 0.05 mg ml-1 improved post-thaw semen quality of cattle and buffalo.


Assuntos
Búfalos , Preservação do Sêmen , Animais , Bovinos , Criopreservação/métodos , Crioprotetores/farmacologia , Glicerol/farmacologia , Grafite , Masculino , Análise do Sêmen/veterinária , Preservação do Sêmen/métodos , Preservação do Sêmen/veterinária , Motilidade dos Espermatozoides , Espermatozoides
5.
Anim Biotechnol ; 32(3): 352-365, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31814520

RESUMO

Aim of this study was to compare different combinations of penetrating intracellular CPAs, i.e., glycerol (G), ethylene glycol (EG), propylene glycol (PG), dimethyl formamide (DM), and methyl acetamide (MA) and extracellular [egg yolk (EY), egg yolk plasma (EYP), low-density lipoproteins (LDL), and coconut water (CW)] in Tris-citric acid-fructose buffer (T) for Labrador dog semen cryopreservation. The study was conducted in two parts, first trial was conducted to assess optimum glycerol concentration (5-7%) in TEY and equilibration time (ET, 2-4 hrs) for Labrador dog semen cryopreservation. Secondly, compatibility of 15% TEY, 15% TEYP, 13% TLDL, and 25% TCW with G, DMF, MA, D + M, EG, and PG was evaluated for in vitro sperm function tests. Decline in sperm attributes, i.e., motility, viability, plasma membrane integrity (PMI), and acrosome integrity (AI)) was significantly (p < 0.05) less in 7% TEY-G and 4 h compared to other concentrations and ET at post-thaw. There was significantly (p < 0.05) less decline in sperm attributes in TEY-G, TEYP-G, TLDL-G, TLDL-D, TLDL-EG, and TCW-D extenders compared to other combinations at post-thaw. However, these parameters were significantly (p < 0.05) high in TEY-G and TEYP-G compared to TEYP-D, TLDL-G, TLDL-D, TLDL-EG, and TCW-D extenders at post-thaw. However, decline in motility, viability, PMI, and AI was identical in these seven extenders. This study concluded that glycerol at a concentration of 7% in TEY and 4 h ET were optimum for successful cryopreservation and besides TEY-G, other combinations of protectants may be an alternative for canine semen cryopreservation.


Assuntos
Ácido Cítrico/farmacologia , Cães , Frutose/farmacologia , Preservação do Sêmen/veterinária , Espermatozoides/fisiologia , Trometamina/farmacologia , Animais , Antioxidantes/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Ácido Cítrico/química , Criopreservação , Crioprotetores/química , Crioprotetores/farmacologia , Frutose/química , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Trometamina/química
6.
Nanoscale Res Lett ; 15(1): 166, 2020 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-32804286

RESUMO

Control over the magnetic interactions in magnetic nanoparticles (MNPs) is a crucial issue to the future development of nanometer-sized integrated "spintronic" applications. Here, we have developed a nanohybrid structure to achieve room temperature ferromagnetism, via a facile, effective, and reproducible solvothermal synthesis method. The plan has been put onto cobalt (Co) NPs, where the growth of Co NPs on the surface of reduced graphene oxide (rGO) nanosheets switches the magnetic interactions from superparamagnetic to ferromagnetic at room temperature. Switching-on ferromagnetism in this nanohybrid may be due to the hybridization between unsaturated 2pz orbitals of graphene and 3d orbitals of Co, which promotes ferromagnetic long-range ordering. The ferromagnetic behavior of Co-rGO nanohybrid makes it excellent material in the field of spintronics, catalysis, and magnetic resonance imaging.

7.
ACS Appl Mater Interfaces ; 12(36): 40828-40837, 2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32786247

RESUMO

Electromagnetic interference (EMI) pollution has now become a subject of great concern with the rapid development of delicate electronic equipment in commercial, civil, and military operations. There has been a surge in pursuit of light-weight, adaptable, effective, and efficient EMI screening materials in recent years. The present article addresses a simple and sensitive approach to synthesize a core/shell carbon nanotube/MoS2 heterostructure supported on reduced graphene oxide (CNT/MoS2-rGO nanohybrid) as an efficient electromagnetic shielding material. The structural and morphological characteristics were accessed through X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy, augmenting successful formation of the CNT/MoS2-rGO nanohybrid. The shielding performance of the as-synthesized samples has been accessed in a wide frequency range of 8-12 GHz. A CNT/MoS2-rGO nanohybrid demonstrates a better EMI shielding performance in comparison to MoS2 nanosheets and MoS2-rGO nanohybrid individually. The CNT/MoS2-rGO nanohybrid having a thickness ∼1 mm shows excellent total shielding effectiveness (SET) as high as 40 dB, whereas MoS2 and MoS2-rGO hybrid lags far, with the average value of SET as 7 and 28 dB, respectively. It also demonstrates that the nanohybrid CNT/MoS2-rGO shields the EM radiation by means of absorption through several functional defects and multiple interfaces present in the heterostructure. Herein, we envision that our results provide a simple and innovative approach to synthesize the light-weight CNT/MoS2-rGO nanohybrid having flexibility and high shielding efficiency and widen its practical applications in stealth technology.

8.
Nanotechnology ; 31(41): 415101, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-32311687

RESUMO

The present article demonstrates the synthesis of the nanocomposite of reduced graphene oxide (rGO) with CdSe and CdSe/V2O5 core/shell quantum dots by a two-step facile synthesis approach and subsequently studies their relative biocompatibility in different cells. Various characterization techniques have been applied including transmission electron microscopy (TEM), an x-ray diffractometer (XRD) and Raman spectroscopy to confirm the successful formation of CdSe-rGO and CdSe/V2O5-rGO nanocomposites. The average sizes of CdSe and CdSe/V2O5 QDs have found to be ∼3 and 5.5 nm, respectively with a good dispersion over the surface of rGO nanosheets. A crystal phase change has occurred during the formation of the V2O5 shell over the surface of CdSe QDs and confirmed through XRD. Raman spectroscopy has shown some useful insight of the surface state of CdSe and consequent changes in the surface with V2O5 shell growth. Further, MTT and cell growth assays have been performed to analyze their biocompatibility in A549 and Hela cells with various concentrations of as-synthesized materials. Our results demonstrate the toxicity of CdSe-rGO nanocomposite to be substantially reduced by the growth of the V2O5 shell. The in vivo studies in Drosophila show a remarkable decrease in the reactive oxygen species (ROS) and apoptosis levels for a CdSe/V2O5-rGO composite as compared to a CdSe-rGO nanocomposite, which paves a promising pathway for the CdSe/V2O5-rGO nanocomposite to be used as an efficient biocompatible material.


Assuntos
Materiais Biocompatíveis/síntese química , Compostos de Cádmio/química , Grafite/química , Compostos de Selênio/química , Compostos de Vanádio/química , Células A549 , Animais , Apoptose/efeitos dos fármacos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Proliferação de Células/efeitos dos fármacos , Drosophila , Células HeLa , Humanos , Nanocompostos/química , Tamanho da Partícula , Pontos Quânticos/química , Espécies Reativas de Oxigênio/metabolismo
9.
Front Pharmacol ; 10: 1016, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31572189

RESUMO

Silver nanoparticles (AgNPs) have many applications in various fields, including biomedical applications. Due to the broad range of applications, they are considered as the leading fraction of manufactured nanoparticles. AgNPs are synthesized by different types of chemical and biological (green) methods. Previously, biologically synthesized AgNPs were considered safe for the environment and humans. However, new toxicity evidence have initiated a more careful assessment to delineate the toxicity mechanisms associated with these nanoparticles. This study demonstrates the use of aqueous gooseberry extract for AgNP preparation in a time- and cost-effective way. Ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy, and dynamic light scattering confirm the formation of AgNPs, with an average size between 50 and 100 nm. Untargeted 1H-nuclear magnetic resonance-based metabolomics revealed manyfold up- and down-regulation in the concentration of 55 different classes of annotated metabolites in AgNP-exposed yeast Saccharomyces cerevisiae cells. Based on their chemical nature and cellular functions, these metabolites are classified into amino acids, glycolysis and the tricarboxylic acid (TCA) cycle, organic acids, nucleotide metabolism, urea cycle, and lipid metabolism. Transcriptome analysis revealed that the genes involved in oxidative stress mitigation maintain their expression levels, whereas the genes of the TCA cycle and lipid metabolism show drastic down-regulation upon AgNP exposure. Moreover, they can induce alteration in histone epigenetic marks by altering the methylation and acetylation of selected histone H3 and H4 proteins. Altogether, we conclude that the selected dose of biologically synthesized AgNPs impose toxicity by modulating the transcriptome, epigenome, and metabolome of eukaryotic cells, which eventually cause disequilibrium in cellular metabolism leading to toxicity.

10.
Nanotechnology ; 30(50): 505704, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31499484

RESUMO

The present work reports nanocomposite of CdSe/V2O5 core-shell quantum dots with reduced graphene oxide (rGO-V-CdSe), as an efficient lightweight electromagnetic wave shielding material, synthesized by a simplistic solvothermal approach. The as-synthesized nanocomposite was analyzed for its structural, compositional and morphological features by x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). The measurement of complex permittivity/permeability and total shielding efficiency of the as-synthesized samples has been done in a wide frequency range of 8-12 GHz (X-band). Compared to rGO and rGO-CdSe, rGO-V-CdSe nanocomposite exhibits significantly enhanced EMI shielding properties in terms of both dielectric loss and total shielding SE T . The high value of real permittivity (average ε'∼70) and the overall shielding effectiveness up to ∼38 dB have been recorded for rGO-V-CdSe nanocomposite. The studies also infer that the absorption contributes more in total shielding than reflection. The high value of dielectric loss and shielding effectiveness could also be attributed to the presence of various defects leading to dipolar and interfacial polarizations. The excellent EMI shielding properties of the nanocomposite in GHz frequency range (X-band) pave an intuitive way for fabricating a versatile EMI shielding nanocomposite material for applications.

11.
Phys Chem Chem Phys ; 21(11): 6265-6273, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30834922

RESUMO

Ultrafast transient absorption (TA) spectroscopy has been carried out to study the charge carrier dynamics of CdSe core and CdSe/V2O5 core/shell quantum dots (QDs). A significant redshift accompanied by broadening in the first excitonic peak was observed in the UV-Vis absorption spectra of the core/shell QDs as the shell thickness increases. This interesting observation is related to a quasi-type-II alignment characterized by the spatial separation of an electron into the core/shell and a hole into the core. The observed optical excitonic spectra have further been used to study the energetics of CdSe and charge separated states with the concept of Marcus theory and confirmed that electron transfer takes place in the Marcus inverted region (). Moreover, the growth kinetics of the CdSe core and CdSe/V2O5 core/shell QDs, studied with TA spectroscopy, exhibits slow electron cooling in core/shell QDs because of the de-coupling of the electronic wave functions with their hole counterpart. These exciting properties reveal a new paradigm shift from CdSe QDs to CdSe/V2O5 core/shell QDs for highly suitable applications in photovoltaics (PV) and optoelectronic devices.

12.
RSC Adv ; 9(38): 21881-21892, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35518872

RESUMO

Magnetic CoFe2O4 nanoparticles decorated onto the surface of a MoS2-reduced graphene oxide (MoS2-rGO/CoFe2O4) nanocomposite were synthesized by a simple two-step hydrothermal method. The electromagnetic (EM) wave absorption performance and electromagnetic interference (EMI) shielding effectiveness of the materials were examined in the frequency range of 8.0-12.0 GHz (X-band). The MoS2-rGO/CoFe2O4 nanocomposite was characterized by various tools such as X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. High-resolution transmission electron microscopy results confirmed the decoration of magnetic nanoparticles onto the surface of the MoS2-rGO nanocomposite with a diameter of 8-12 nm. The multiple interfacial polarization, moderate impedance matching, and defect dipole polarization improve the dielectric and magnetic loss of the materials, which leads to strong attenuation loss ability of incident EM energy within the shield. The pure MoS2-rGO nanocomposite represents total shielding effectiveness (SET ∼16.52 dB), while the MoS2-rGO/CoFe2O4 nanocomposite exhibits total shielding effectiveness (SET ∼19.26 dB) over the entire frequency range. It may be explained that the magnetic nanoparticles (CoFe2O4) serve as excellent conductive and magnetic fillers with a large surface area, leading to the migration of charge carriers at multi-interfaces.

13.
RSC Adv ; 9(39): 22232-22239, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-35519470

RESUMO

In this paper, we demonstrate a facile solvothermal synthesis of a vanadium(v) doped MoS2-rGO nanocomposites for highly efficient electrochemical hydrogen evolution reaction (HER) at room temperature. The surface morphology, crystallinity and elemental composition of the as-synthesized material have been thoroughly analyzed. Its fascinating morphology propelled us to investigate the electrochemical performance towards the HER. The results show that it exhibits excellent catalytic activity with a low onset potential of 153 mV versus reversible hydrogen electrode (RHE), a small Tafel slope of 71 mV dec-1, and good stability over 1000 cycles under acidic conditions. The polarization curve after the 1000th cycle suggests there has been a decrement of less than 5% in current density with a minor change in onset potential. The synergistic effects of V-doping at S site in MoS2 NSs leading to multiple active sites and effective electron transport route provided by the conductive rGO contribute to the high activity for the hydrogen evolution reaction. The development of a high-performance catalyst may encourage the effective application of the as-synthesized V-doped MoS2-rGO as a promising electrocatalyst for hydrogen production.

14.
Nanotechnology ; 29(24): 245203, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29561266

RESUMO

This work reports a detailed study of reduced graphene oxide (rGO)-Fe3O4 nanoparticle composite as an excellent electromagnetic (EM) interference shielding material in GHz range. A rGO-Fe3O4 nanoparticle composite was synthesized using a facile, one step, and modified solvothermal method with the reaction of FeCl3, ethylenediamine and graphite oxide powder in the presence of ethylene glycol. Various structural, microstructural and optical characterization tools were used to determine its synthesis and various properties. Dielectric, magnetic and EM shielding parameters were also evaluated to estimate its performance as a shielding material for EM waves. X-ray diffraction patterns have provided information about the structural and crystallographic properties of the as-synthesized material. Scanning electron microscopy micrographs revealed the information regarding the exfoliation of graphite into rGO. Well-dispersed Fe3O4 nanoparticles over the surface of the graphene can easily be seen by employing transmission electron microscopy. For comparison, rGO nanosheets and Fe3O4 nanoparticles have also been synthesized and characterized in a similar fashion. A plot of the dielectric and magnetic characterizations provides some useful information related to various losses and the relaxation process. Shielding effectiveness due to reflection (SER), shielding effectiveness due to absorption (SEA), and total shielding effectiveness (SET) were also plotted against frequency over a broad range (8-12 GHz). A significant change in all parameters (SEA value from 5 dB to 35 dB for Fe3O4 nanoparticles to rGO-Fe3O4 nanoparticle composite) was found. An actual shielding effectiveness (SET) up to 55 dB was found in the rGO-Fe3O4 nanoparticle composite. These graphs give glimpses of how significantly this material shows shielding effectiveness over a broad range of frequency.

15.
Nanoscale Res Lett ; 12(1): 298, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28449538

RESUMO

In this article, we proposed a facile one-step synthesis of Fe3O4 nanoparticles of different shapes and sizes by co-precipitation of FeCl2 with piperidine. A careful investigation of TEM micrographs shows that the shape and size of nanoparticles can be tuned by varying the molarity of piperidine. XRD patterns match the standard phase of the spinal structure of Fe3O4 which confirms the formation of Fe3O4 nanoparticles. Transmission electron microscopy reveals that molar concentration of FeCl2 solution plays a significant role in determining the shape and size of Fe3O4 nanoparticles. Changes in the shape and sizes of Fe3O4 nanoparticles which are influenced by the molar concentration of FeCl2 can easily be explained with the help of surface free energy minimization principle. Further, to study the magnetic behavior of synthesized Fe3O4 nanoparticles, magnetization vs. magnetic field (M-H) and magnetization vs. temperature (M-T) measurements were carried out by using Physical Property Measurement System (PPMS). These results show systematic changes in various magnetic parameters like remanent magnetization (Mr), saturation magnetization (Ms), coercivity (Hc), and blocking temperature (T B) with shapes and sizes of Fe3O4. These variations of magnetic properties of different shaped Fe3O4 nanoparticles can be explained with surface effect and finite size effect.

16.
Nanoscale Res Lett ; 10(1): 1055, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26334545

RESUMO

In the present article, an effective, one-step, and environmentally benign protocol for the synthesis of gold nanoparticles has been discussed. The black cardamom extract is used as a reducing agent for HAuCl4.3H2O. In order to synthesize gold nanoparticles, an aqueous solution of HAuCl4.3H2O was mixed with an optimized concentration of black cardamom extract where 1,8-cineole is the dominant component. Choosing black cardamom extract as a reducing agent can be justified under the light of the fact that it has a very fast reducing ability. Gold nanoparticles with different shapes and sizes were synthesized by varying the ratio of AuCl4 ions to black cardamom extract. Kinetics of reactions has been evaluated through monitoring of surface plasmon behavior of gold nanoparticles as a function of time. Based on Fourier transform infrared spectroscopy (FTIR) studies, a tentative mechanism of reduction of Au nanoparticles has also been proposed which includes oxidation of 1,8-cineole to 2-oxo-1,8-cineole. Further, a comprehensive study to investigate the effect of pH on the synthesis of Au nanoparticles has been carried out.

17.
Free Radic Biol Med ; 65: 217-223, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23774043

RESUMO

In this paper, we have shown that gold nanoparticles (Au (NPs)) embedded in Rubia cordifolia (RC) matrix (RC-Au (NPs)) exhibit a high therapeutic value relating to its anti-inflammatory characteristics. It was prepared by utilizing the reducing properties of RC to convert HAuCl4 into Au (NPs). In order to compare its effectiveness, with respect to Au (NPs), the latter was synthesized separately by reducing HAuCl4 with lemon extract. These Au (NPs) along with RC-Au (NPs) were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), and UV-visible spectroscopy. The enhancement in anti-inflammatory characteristics was assessed as its inhibitory potential for lipopolysaccharide (LPS)-induced nitric oxide (NO) release, by rat peritoneal macrophages. The RC-Au (NPs) significantly enhanced its potential to inhibit NO release, which was reported in terms of inhibitory concentration for 50% inhibition (IC50=11.98 ng/ml), as compared to either RC extract (IC50=47 × 10(3)ng/ml) or to Au (NPs) (IC50=587.50 ng/ml).


Assuntos
Macrófagos Peritoneais/efeitos dos fármacos , Nanoconjugados , Extratos Vegetais/administração & dosagem , Rubia/química , Animais , Anti-Inflamatórios/administração & dosagem , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Ouro/administração & dosagem , Lipopolissacarídeos/toxicidade , Macrófagos Peritoneais/imunologia , Nanopartículas Metálicas/química , Nanoconjugados/química , Ratos
18.
Injury ; 44(1): 66-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22204771

RESUMO

INTRODUCTION: Morel-Lavallée lesion is a rare cause of subcutaneous swelling, caused by post-traumatic shearing of the hypodermis from the underlying fascia. Treatment of such lesions is still not well established. OBJECTIVE: To evaluate the results of conservative treatment for these lesions using doxycycline induced sclerodesis followed by elastic compression bandaging. PATIENTS AND METHODS: We treated 16 Morel-Lavallée lesions between May 2005 and December 2008. These lesions developed in 13 male and 3 female patients (mean age 41 years; range 10-74 years) due to various modes of trauma. The lesion involved the thigh region in 13 patients with trochanteric region, gluteal, lower back, and lower abdominal wall being other regions involved. An area of palpable fluctuance was the most consistent examination finding. Treatment was effected by fluid aspiration, doxycycline instillation, and compressive elastic bandaging. Healing was defined as the loss of fluctuation with complete absence of fluid on ultrasonography. RESULTS: The average duration of the persistence of the lesion was 13 months (range, 6-23 months). Most of the lesions had been aspirated previously multiple number of times, average being 3.44 times (range, 1-6 times). All lesions were aspirated and found to be negative on culture. The mean follow up period was 50.44 months (range, 31-74 months). 11 patients showed complete resolution of fluid collection at 4 weeks with another 4 patients resolving at 8 weeks follow up. The lesion persisted in one patient at 12 weeks due to non-compliance to compressive elastic bandaging which subsequently resolved on repeating the procedure. All the lesions healed without any infections or necrosis. No recurrences were detected during the follow up period. A persistent non-fluctuant contour deformity, decreased skin mobility over the site of lesion, and feeling of tightness were the most common problems faced on long term follow up. CONCLUSION: Closed degloving injuries can be managed satisfactorily with doxycycline induced obliteration of the cavity with early healing time without recurrences.


Assuntos
Antibacterianos/administração & dosagem , Bandagens Compressivas , Doxiciclina/administração & dosagem , Linfedema/terapia , Lesões dos Tecidos Moles/terapia , Adolescente , Adulto , Idoso , Biópsia por Agulha Fina , Criança , Desbridamento , Feminino , Seguimentos , Humanos , Linfedema/diagnóstico por imagem , Linfedema/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Radiografia , Lesões dos Tecidos Moles/diagnóstico por imagem , Lesões dos Tecidos Moles/tratamento farmacológico , Fatores de Tempo , Resultado do Tratamento , Cicatrização
19.
J Hand Microsurg ; 5(2): 92-5, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24426686

RESUMO

Isolated fractures of the carpal hamate are rare. We describe a case of 28-year-old male patient who sustained a rare pattern of wrist injury: combined intraarticular fracture of the body and the hook of hamate in the non-dominant left hand. The patient was treated with percutaneous pinning of the fracture of hamate body.

20.
J Clin Orthop Trauma ; 3(1): 58-61, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25983458

RESUMO

The treatment of displaced proximal tibial fractures is challenging. Recent developments in the techniques of internal fixation, including the development of locking plates and minimally invasive surgical techniques have revolutionaries the treatment of such fractures. We present a case of proximal displaced tibial fracture that was treated with anatomical proximal tibial locking plate using minimally invasive percutaneous plate osteosynthesis. Patient made uneventful recovery even after he sustained re-injury and plate bending and was manipulated under anaesthesia for the same.

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