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1.
Behav Neurosci ; 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32223277

RESUMO

Depression affects both women and men, but women are 2 times more susceptible to the incidence of depression. Although a number of studies report sex differences in stress responses, it remains unclear which animal models of depression can better mimic the sex difference in human depression. The majority of stress models used male rodents whereas fewer studies included females. The aims of this study were to determine which rat stress models mimic the sex difference in depression and to identify sex-specific risk factors for depression model-induced depression-like behaviors. Here, we compared subchronic variable stress (SCVS) and chronic unpredictable mild stress (CUMS) models to evaluate the susceptibility versus resilient phenotypes in male and female rats. SCVS induced depression-like behaviors in female rats only. The CUMS paradigm was more likely to induce depression-like behaviors in male rats. Furthermore, to explore the underlying mechanisms, we used quantitative reverse transcriptase polymerase chain reaction to examine and compare the messenger RNA (mRNA) levels of various transcripts previously shown to be involved in psychiatric disorders in RNA-sequencing/microarray studies including serotonin receptor-7, early growth response-2, histone deacetylase-2, roundabout guidance receptor-2 (Robo2), serum/glucocorticoid regulated kinase-2, orthodenticle homeobox-2, parathyroid hormone-2 receptor, and neuronal PAS domain protein-4 in the hippocampus after exposure of rats to SCVS and CUMS. Our results showed that SCVS significantly altered the mRNA levels of neuronal PAS domain protein-4, orthodenticle homeobox-2, Robo2, parathyroid hormone-2 receptor, and serum/glucocorticoid regulated kinase-2 in the female hippocampus only, and histone deacetylase-2 in only the male hippocampus. CUMS significantly changed the mRNA levels of one transcript (Robo2) in the female hippocampus only when compared with SCVS. Overall, this study shows that SCVS can be used to study sex differences in depression-like behaviors in rats. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

2.
Chemistry ; 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32227539

RESUMO

The sluggish kinetics and demand of high anodic potential are the bottlenecks for OER that severely hamper the deployment of water splitting modules for H 2 production. Although transition metal oxides based electrocatalysts have been envisioned as potential contender in this quest, but their low conductivity, instability and limited number of active sites are among the common impediments that need to be addressed to enhance their inherent catalytic potential for enhanced OER activity. Herein, we report the controlled assembly of transition metal oxides i.e., Cu@CuO x nanoclusters (NCs, ≈ 2nm) and Co@CoO x beaded nanoclusters (BNCs, ≈2nm) on thiol-functionalized graphene oxide nanosheets as novel and highly efficient electrocatalysts for OER. Thiol functionality was incorporated via selective epoxidation reaction on the surface of graphene oxide to achieve chemically exfoliated nanosheets to enhance its conductivity and trapping ability for metal oxides NCs. During electrocatalytic reaction, an overpotential of 290 mV and 310 mV is required to achieve a current density of 10 mA/cm 2  for BNCs and NCs respectively, while exhibiting long-term stability (≈50 h) in alkaline medium (1 M KOH) with no dissolution. Moreover, the smaller Tafel slopes (54 mV/dec for BNCs and 66 mV/dec for NCs), and a Faradic efficiency of ≈96 % indicate not only the selectivity but also the tailored heterogeneous electrons transfer rate that is essentially required for fast electrode kinetics.

3.
Microsc Res Tech ; 2020 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-32170794

RESUMO

Green synthesis of nanoparticles using plants has become a promising substitute for the conventional chemical synthesis methods. In the present study, our aim was to synthesize chromium oxide nanoparticles (Cr2 O3 NPs) through a facile, low-cost, eco-friendly route using leaf extract of Rhamnus virgata (RV). The formation of Cr2 O3 NPs was confirmed and characterized by spectroscopic profile of UV-Vis, EDX, FTIR, and XRD analyses. The UV-visible spectroscopy has confirmed the formation of Cr2 O3 NPs by the change of color owing to surface plasmon resonance. The bioactive functional groups present in the leaf extract of RV involved in reduction and stabilization of Cr2 O3 NPs were determined by FTIR analysis. Based on XRD analysis, crystalline nature of Cr2 O3 NPs was determined. The morphological shape and elemental composition of Cr2 O3 NPs were investigated using SEM and EDX analyses, respectively. With growing applications of Cr2 O3 NPs in biological perspectives, Cr2 O3 NPs were evaluated for diverse biopotentials. Cr2 O3 NPs were further investigated for its cytotoxicity potentials against HepG2 and HUH-7 cancer cell lines (IC50 : 39.66 and 45.87 µg/ml), respectively. Cytotoxicity potential of Cr2 O3 NPs was confirmed against promastigotes (IC50 : 33.24 µg/ml) and amastigotes (IC50 : 44.31 µg/ml) using Leishmania tropica (KMH23 ). The Cr2 O3 NPs were further evaluated for antioxidants, biostatic, alpha-amylase, and protein kinase inhibition properties. Biocompatibility assay was investigated against human macrophages which confirmed the nontoxic nature of Cr2 O3 NPs. Overall, the synthesized Cr2 O3 NPs are biocompatible and nontoxic and proved to possess significant biopotentials. In future, different in vivo studies are needed to fully investigate the cytotoxicity and mechanism of action associated with these Cr2 O3 NPs.

4.
Pak J Pharm Sci ; 33(1): 149-160, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32122843

RESUMO

A series of new compounds (5a-q), derived from 5-(1-(4-nitrophenylsulfonyl) piperidin-4-yl)-4-phenyl-4H-1,2,4-triazole-3-thiol (3) were proficiently synthesized to evaluate their biological activities. 1-(4-Nitrophenylsulfonyl) piperidine-4-carbohydrazide (2) was refluxed with phenylisothiocyanate to yield an adduct which was cyclized to compound 3 by reflux reaction with 10 % potassium hydroxide. The targeted compounds 5a-q, were synthesized by stirring alkyl/aralkyl halides (4a-q) and compound 3 in a polar aprotic solvent. 1H-NMR, 13C-NMR, EI-MS and IR spectral techniques were employed to confirm the structures of all the synthesized compounds. The compounds were biologically evaluated for BSA binding studies followed by anti-bacterial, anti-inflammatory and acetylcholinesterase (AChE) activities. The active sites responsible for the best AChE inhibition were identified through molecular docking studies. Compound 5e bearing 4-chlorobenzyl moiety found most active antibacterial and anti-inflammatory agent among the synthesized compounds. The whole library of synthesized compounds except compounds 5d and 5f was found highly active for AChE inhibition and recommended for in vivo studies so that their therapeutic applications may come in utilization.

5.
Neuroreport ; 31(3): 213-219, 2020 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-31895742

RESUMO

Major depressive disorder affects both women and men but females are two times more susceptible to the incidence of depression. The majority of stress models used male rodents, whereas fewer studies included females. Volumetric reductions have been reported in brain areas critical for the stress response, such as prefrontal cortex, and remodeling of dendritic spines has been proposed as an underlying factor. The aim of this study was to determine the effects of subchronic variable stress (SCVS) in males, sham, and specifically in ovariectomized (OVX) female mice. Here, we used 6 days SCVS model to induce depressive-like behavior, and only the OVX female mice showed the depressive-like behavior, while males showed resilient type behavior. Only OVX female mice showed significant increase in dendritic spine density in SCVS paradigm. Overall, this study suggests that (1) the effects SCVS produced on the behavior of males and OVX females and (2) SCVS may induce rapid and sustained changes of PL neurons, which highlights the importance of gonadal hormones in studying depression.

6.
Spectrochim Acta A Mol Biomol Spectrosc ; 228: 117685, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31748156

RESUMO

With the help of computational chemistry tools, three non-fullerene acceptors, which are 2-methylene-malononitrile (M-1), 2-(3-methyl-5-methylene-2-thioxothiazolidin-4-ylidene) malononitrile (M-2) and 1-methyl-5-methylene-2,6-dioxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (M-3), are designed with naphthalene diimide (NDI) central unit. Their different photovoltaic and optoelectronic properties like absorption spectrum, electrons density, solubility strength, reorganization energies, % ETC from donor to acceptor part, excitation energies, oscillating strength, morphology and crystallinity of device for constructing the thin film bulk hetro junction devices were computed at the WB97XD/6-31 G (d, p) level of density functional theory (DFT). Expected open circuit voltages of designed molecules are high as 4.05 eV to 4.49 eV, which are significantly larger than that of the previously reported 3-methyl-5-methylene-2-thioxothiazolidin-4-one (R) with the value of 3.60 eV at the zero current level. Charge carrier mobilities of designed molecules are high due to having low re-organization energies varying from 0.0163 eV to 0.0280 eV for electron and 0.0160 eV to 0.0190 eV for hole, strong absorption properties between the 420 nm to 550 nm in chloroform and 400 nm to 540 nm in gas phase conditions, respectively.

7.
Crit Rev Food Sci Nutr ; 60(3): 351-374, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30614244

RESUMO

Brain is a central and pivotal organ of human body containing the highest lipids content next to adipose tissue. It works as a monitor for the whole body and needs an adequate supply of energy to maintain its physiological activities. This high demand of energy in the brain is chiefly maintained by the lipids along with its reservoirs. Thus, the lipid metabolism is also an important for the proper development and function of the brain. Being a prominent part of the brain, lipids play a vast number of physiological activities within the brain starting from the structural development, impulse conduction, insulation, neurogenesis, synaptogenesis, myelin sheath formation and finally to act as the signaling molecules. Interestingly, lipids bilayer also maintains the structural integrity for the physiological functions of protein. Thus, in light to all of these activities, lipids and its metabolism can be attributed pivotal for brain health and its activities. Decisively, the impaired/altered metabolism of lipids and its intermediates puts forward a key step in the progression of different brain ailments including neurodegenerative, neurological and neuropsychiatry disorders. Depending on their associated underlying pathways, they serve as the potential biomarkers of these disorders and are considered as necessary diagnostic tools. The present review discusses the role and level of altered lipids metabolism in brain diseases including neurodegenerative diseases, neurological diseases, and neuropsychiatric diseases. Moreover, the possible mechanisms of altered level of lipids and their metabolites have also been discussed in detail.

8.
Clin Chim Acta ; 502: 41-54, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31857069

RESUMO

Autism spectrum disorder (ASD) refers to a group of complex neurodevelopmental disorders characterized by social interaction and communication deficits and repetitive and stereotyped behaviors. As the etiology and pathogenesis of the disorder have not yet been elucidated, specific treatment and reliable diagnostic biomarkers are not available. Early behavioral interventions have been shown to substantially improve symptoms in children with ASD. Given the rapidly increasing prevalence of ASD, there is an urgent need to identify related diagnostic biomarkers. Although specific diagnostic markers for ASD have not been identified, the related research has made progress in different aspects. This review summarizes recent findings of the use of genes, proteins, peptides, and metabolites as diagnostic markers for ASD. The associated techniques include genetic testing and proteomic and metabolomic analyses. In addition, some studies have focused on single or several proteins and metabolites. Moreover, transcriptomic analysis, immune disturbances and cytokine may also be used for this purpose. The pathogenesis involving genes, proteins, and metabolites is also discussed here.

9.
Natl J Maxillofac Surg ; 10(2): 195-199, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31798255

RESUMO

Objectives: The present study aims to determine the incidence and prevalence of trigeminal neuralgia (TN) in study population and difference in prevalence of TN in urban and rural population. Materials and Methods: This retrospective study includes 1215 study participants with typical idiopathic TN. Data regarding the age of onset, gender, site of involvement, and clinical presentations were retrieved from clinical records of patients reported from January 2011 to January 2018. Results: The study population consists of 1215 study participants aged between 21 and 87 years, with a mean age of 50.62 ± 15.872 years. The mandibular nerve is involved in most of the cases (56.9%), followed by maxillary nerve (42%). The right side of the face (57.1%) is more involved than the left side (38.8%). TN was more prevalent (52.4%) in rural population than urban population (47.6%). Conclusion: TN is more common in females than males, the right side of the face is more involved than the left side, and it is more commonly found in rural population than urban population.

10.
Sci Rep ; 9(1): 20077, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882757

RESUMO

Glacial avalanche hazards can threaten lives and damage infrastructures in high altitude mountainous regions. In April 2012 a gigantic ice plus rock avalanche destroyed military camp at Gyari and killed 139 persons. Antecedent, the objectives of this study are to simulate and model Gyari camp glacial avalanche with reference to its extent, height, momentum, velocity and pressure and, to simulate and model the other potential glacial avalanche prone areas in Shyok basin. To simulate the Gyari camp glacial hazard and other potential glacial avalanche hazards, an empirical process based Glacier Avalanche Model; Rapid Access Mass Movement Simulation (RAMMS) is used. The RAMMS model encompasses the variables like avalanche release height and release area for the conduct of simulation. The model output of Gyari glacial avalanche hazard resulted from a max pressure of 2500 KPa, max velocity of 90 m/s, and the max flow height of 40 m, while the resulted output debris volume calculated was 4.3145 million m3. The calibrated agreement was found in extent and height of actual debris in comparison with RAMMS simulated output. The potential hazardous glacial avalanche prone areas of Shyok basin were simulated by RAMMS model after the model being calibrated to the actual incident of Gyari. The study has resulted in identifying the Siachen glacier conflict zone being more prone to avalanche hazards because of host factors in general and the anthropogenic factor in particular.

11.
Int J Pharm ; 572: 118816, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31678527

RESUMO

Amorphous solid dispersion (ASD) is one of the most promising strategies for improving the solubility of active pharmaceutical ingredients (APIs) with low aqueous solubility. Solvent-based techniques such as electrospinning (ES), spray-drying (SD) and rotary evaporation (RE), have all previously been shown to be effective techniques for formulating ASDs. To date however, the effect of these processing techniques on the physicochemical properties and ASD homogeneity or "quality of ASD" produced remains largely unexplored. This work uses ibuprofen (IBU) as a model BCS class II API with two cellulosic excipients, HPMCAS and HPMCP-HP55 to produce ASDs by employing ES, SD and RE processing techniques. The physicochemical, morphological and dissolution properties of each sample were evaluated and the ASD forming strengths of each of the polymers were assessed using Differential Scanning Calorimetry (DSC). Principal |Component Analysis (PCA) of Raman spectra of crystalline and amorphous IBU was employed for qualitative analysis of ASD homogeneity and subsequent ASD stability during long-term storage. Results show that while ASD formation is predominantly dependent on API:excipient ratio, the ASD homogeneity is highly dependent on processing technique. Dissolution studies show that electrospun samples had the highest API release rate due to their fibrous morphology and higher specific surface area. However, these samples were the least homogenous of all ASDs produced thereby potentially influencing sample stability during long term storage. In addition, the higher melting point depression, higher Tg, and increased abundance of functional groups suitable for hydrogen bonding, show HPMCAS to be a significantly better ASD co-former when compared with HPMCP-HP55.

12.
Geospat Health ; 14(2)2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31724384

RESUMO

This study focuses on the risk of pollen allergy due to paper mulberry (Broussonetia papyrifera L.), an Asian invasive plant species now common in large parts of the world. Pollen plays a key role in the pathogenesis of respiratory allergic diseases, particularly rhinitis and asthma, and Islamabad, a major metropolitan city, is severely affected by allergy owing to B. papyrifera pollen. Due to its seasonality and other relationships with climatic variables, we used remote sensing to monitor the trend of pollen count. We also mapped the localisation of patients affected by pollen allergy using geographic information systems. The maximum likelihood algorithm was applied to SPOT-5 satellite imagery for land use/land cover classification. Temporal analysis of remotely sensed data revealed an increasing trend of paper mulberry density towards the southern and south-western part of Islamabad. Although not evident during rainfall, a clear positive correlation was found between patient count and pollen count. Field survey data and hotspot spatial analysis of allergy patients revealed that residents of Shakerperiyan and Lok Virsa areas (Sectors H-8, I-8, I-9, G-8, G-7 and G-6 in Islamabad) had more pronounced symptoms compared to residents of other sectors. The methodology adopted used in this study can be used to map the distribution of similar invasive species in other parts of the country.

13.
Environ Sci Pollut Res Int ; 26(36): 36274-36286, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31713824

RESUMO

In energy economics literature, we found few studies on the association between environmental quality energy consumption and financial development. The current study is an attempt to contribute in literature by examining the link between carbon dioxide (CO2) emissions, financial development, energy consumption, and economic growth, in South East Asian economies for the period 1980-2017 using annual time series data. For empirical analysis, Bound tests for cointegration and error correction approach are used. The estimated results confirm that financial development has positive impact on environmental quality. On the other hand, in the long run, the rise in energy consumption economic growth and trade openness is unfavorable for environment quality. Our results confirm U-shaped relationship between economic growth and environmental quality that is a proof of environmental Kuznets curve (EKC). Additionally, the government needs to design different modes of energy consumption to solve the problem of environmental degradation. Moreover, the major conclusion extends new insight for authority to make a comprehensive trade and financial policies to improve environmental quality.


Assuntos
Poluentes Atmosféricos/análise , Dióxido de Carbono/análise , Desenvolvimento Econômico/estatística & dados numéricos , Ásia Sudeste , Pesquisa Empírica , Fontes Geradoras de Energia/economia , Fontes Geradoras de Energia/estatística & dados numéricos , Meio Ambiente , Internacionalidade
14.
Int J Biol Macromol ; 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31730950

RESUMO

In this work, the preparation of novel biocompatible polyurethane (PU) elastomers were carried out using curcumin and 1,4-butanediol (1,4-BDO) via step growth polymerization reaction of hydroxyl terminated polybutadiene (HTPB), toluene diisocyanate (TDI) and chitin to improve the biocompatibility, antibacterial and antioxidant properties of PU elastomers. Five samples were synthesized by varying moles ratio of curcumin and 1,4-BDO. The structural study of blends was done by FTIR spectroscopy which confirmed the incorporation of curcumin and 1,4-BDO into the polyurethane matrix. TGA analysis of polyurethane (PU) blends showed good thermal stability with 0.25 M curcumin and 1.75 M 1,4-BDO. Measurements of antibacterial properties were done via agar diffusion method which showed outstanding potential against selected strains of bacteria. The results revealed that biocompatibility, antibacterial and antioxidant potential of purposed polyurethanes elastomers were improved by the incorporation of curcumin which might be the precursor of biomedical applications. Collectively, this work is a footstep towards the synthesis of innovative biocompatible materials which made it suitable for biological applications.

15.
Endocr Res ; : 1-18, 2019 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-31608702

RESUMO

Estrogen (E2) modulates a wide range of neural functions such as spine formation, synaptic plasticity, and neurotransmission in the hippocampus. Dendritic spines and synapse numbers in hippocampal neurons of female rats cyclically fluctuate across the estrous cycle, but the key genes responsible for these fluctuations are still unknown. In order to address this question, we explore the hippocampal transcriptome via RNA-sequencing (RNA-seq) at the proestrus (PE) and estrus (ES) stages in female rats. At standard fold-change selection criteria, 37 differentially expressed genes (DEGs) were found in PE vs. ES groups (FDR adjusted p-value (q)<0.05). The transcriptional changes identified by RNA-seq were confirmed by quantitative real-time PCR. To gain insight into the function of the DEGs, the E2-regulated genes were annotated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes database (KEGG). Based on GO and KEGG pathways, the identified DEGs of PE vs. ES stages are involved in extracellular matrix formation, regulation of actin cytoskeleton, oxidative stress, neuroprotection, immune system, oligodendrocyte maturation and myelination, signal transduction pathways, growth factor signaling, retinoid signaling, aging, cellular process, metabolism and transport. The profiles of the gene expression in the hippocampus identified at the PE vs. ES stages were compared with the gene expression profiles in ovariectomized (OVX) rats receiving E2 replacement via RNA-seq and qPCR. The profiles of gene expression between the OVX+E2 and the estrous cycle were different and the possible causes were discussed.

16.
Pak J Pharm Sci ; 32(3 Special): 1343-1348, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31551213

RESUMO

There are still no FDA approved drugs for NAFLD so far. Vitamin D may be a good therapeutic option for NAFLD patients due to its insulin sensitizing and anti-inflammatory properties. The purpose is to investigate the effect of oral vitamin D supplementation on various parameters in NAFLD patients. In this double blind randomized placebo controlled trial, 109 patients of NAFLD diagnosed by abdominal ultrasound and liver enzymes were divided into two groups for treatment with oral capsule of vitamin D3 50,000 IU and capsule placebo weekly for a period of 12 weeks. Anthropometric, chemical, metabolic and inflammatory parameters were assessed pre and post treatment by using SPSS 16. After 12 weeks oral treatment with vitamin D , its level increased significantly in vitamin D group from 12.5±4.2 to 24.5±3.8 ng/ml p =0.003 vs placebo group. This rise was further accompanied by decrease in HOMA-IR (4.56±1.6 to 3.26± 1.8 p=0.003) liver enzymes (i.e. ALT: 72.±17.6 to 54.5±14.5 IU/L p=0.04; AST: 68±14.5 to 46.± 10.5 p =0.002) serum CRP 3.25±0.68 to 2.28±0.44 mg/L p =0.06 and increase in serum adiponectin 8.56 ±1.12 to 10.44±2.35 mg/L p =0.03 as compared to placebo group. However non significant changes were observed in both groups in terms of body weight, BMI, and serum lipid profiles. Vitamin D supplementation not only improved its own status but also caused a significant amelioration in metabolic, chemical and inflammatory parameters in NAFLD patients. So it should be consider as an adjunctive therapy in NAFLD patients.


Assuntos
Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Vitamina D/uso terapêutico , Adiponectina/sangue , Administração Oral , Adulto , Índice de Massa Corporal , Peso Corporal/efeitos dos fármacos , Proteína C-Reativa/análise , Método Duplo-Cego , Feminino , Humanos , Resistência à Insulina , Lipídeos/sangue , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Hepatopatia Gordurosa não Alcoólica/metabolismo , Placebos , Resultado do Tratamento , Vitamina D/administração & dosagem
17.
J Mol Model ; 25(10): 311, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31512040

RESUMO

Nowadays, scientists are trying to develop low-cost fullerene free acceptors for small organic photovoltaic cells in order to overcome the limitations of fullerene derivatives. Current research work deals with theoretical study on three non-fullerene acceptors based on indaceno, dithiophene core, and thiophene bridge units linked with dissimilar end non-fullerene groups which act as strong acceptor moieties. Different optoelectronic characteristics of the designed molecules were calculated and compared with the reference compound R (indaceno dithiophene-based fused ring acceptor) which is recently reported. Results shows that C2 and C3 exhibit broad absorption spectrum and lower band gap whereas C2 and C1 exhibit highest open-circuit voltages VOC value with B3LYP and MPW1PW91 functionals respectively as compared with the R. All designed molecules have high dipole moment values, lower value of hole reorganization energy λh than electron reorganization energy λe which reflects that our designed acceptor molecules are good candidates for organic photovoltaics. Graphical abstract Absorption spectra of R and three designed non-fullerene acceptors with strong absorption band in the visible region of solar cells spectrum.

18.
Polymers (Basel) ; 11(10)2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31557811

RESUMO

In recent years, there has been considerable interest in the use of natural fibers as potential reinforcing fillers in polymer composites despite their hydrophilicity, which limits their widespread commercial application. The present study explored the fabrication of nanocomposites by melt mixing, using an internal mixer followed by a compression molding technique, and incorporating rice husk (RH) as a renewable natural filler, montmorillonite (MMT) nanoclay as water-resistant reinforcing nanoparticles, and polypropylene-grafted maleic anhydride (PP-g-MAH) as a compatibilizing agent. To correlate the effect of MMT delamination and MMT/RH dispersion in the composites, the mechanical and thermal properties of the composites were studied. XRD analysis revealed delamination of MMT platelets due to an increase in their interlayer spacing, and SEM micrographs indicated improved dispersion of the filler(s) from the use of compatibilizers. The mechanical properties were improved by the incorporation of MMT into the PP/RH system and the reinforcing effect was remarkable as a result of the use of compatibilizing agent. Prolonged water exposure of the prepared samples decreased their tensile and flexural properties. Interestingly, the maximum decrease was observed for PP/RH composites and the minimum was for MMT-reinforced and PP-g-MAH-compatibilized PP/RH composites. DSC results revealed an increase in crystallinity with the addition of filler(s), while the melting and crystallization temperatures remained unaltered. TGA revealed that MMT addition and its delamination in the composite systems improved the thermal stability of the developed nanocomposites. Overall, we conclude that MMT nanoclay is an effective water-resistant reinforcing nanoparticle that enhances the durability, mechanical properties, and thermal stability of composites.

19.
Ultrason Sonochem ; 59: 104736, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31473424

RESUMO

An upsurge in sustainable energy demands has ultimately made supercapattery one of the important choice for energy storage, owing to highly advantageous energy density and long life span. In this work, novel strontium based mixed phased nanostructures were synthesized by using probe sonicator with sonication power 500 W at frequency of 20 kHz. The synthesized material was subsequently calcined at different temperature ranging from 200 to 800 °C. Structural and morphological analysis of the synthesized materials reveals the formation of mixed particle and rod like nanostructures with multiple crystal phases of strontium oxides and carbonates. Crystallinity, grain size and morphology of grown nanomaterials significantly improved with the increase of calcination temperature due to sufficient particle growth and low agglomeration. The electrochemical performance analysis confirms the redox activeness of the Sr-based electrode materials. Material calcined at 600 °C show high specific capacitance of 350 F g-1 and specific capacity of 175 C g-1 at current density of 0.3 A g-1 due to less particle agglomeration, good charge transfer and more contribution of electrochemical active sites for redox reactions. In addition, the developed supercapattery of Sr-based nanomaterials//activated carbon demonstrated high performance with maximum energy density of 21.8 Wh kg-1 and an excellent power density of 2400 W kg-1 for the lower and higher current densities. Furthermore, the supercapattery retain 87% of its capacity after continuous 3000 charge/discharge cycles. The device characteristics were further investigated by analyzing the capacitive and diffusion controlled contributions. The versatile strategy of developing mixed phased nanomaterials pave the way to synthesize other transition metal based nanomaterials with superior electrochemical performance for hybrid energy storage devices.

20.
Microsc Res Tech ; 82(11): 1891-1902, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31415132

RESUMO

Herbal medicines frequently suffer with quality controversies because of similar species or varieties. This often leads to sophistication or admixture of the crude drug as they share various look alike physical features. Commercially, stalks of Caralluma edulis are commonly adulterated with other species because of their analogous morphology. In the present research, the microscopic standardization of the drug was performed by structural, histological, and anatomical features. Pharmacognostical characterization was carried out by physicochemical (moisture content, swelling index, pH value, ash values, and extractive values) and fluorescence analysis. The chemical characterization by UV-Visible, Fourier transform infrared spectroscopy, and high-performance liquid chromatography was also performed that disclosed the chief phytoconstituents of the herbal drug. The above mentioned constraints, being reported for the first time in C. edulis, are substantial in establishing the microscopic and pharmacopoeial standards for future identification and authentication.


Assuntos
Apocynaceae/anatomia & histologia , Preparações de Plantas/química , Plantas Medicinais/anatomia & histologia , Apocynaceae/classificação , Cromatografia Líquida de Alta Pressão , Farmacognosia , Folhas de Planta/anatomia & histologia , Plantas Medicinais/classificação , Espectroscopia de Infravermelho com Transformada de Fourier
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