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1.
Nano Lett ; 24(2): 708-714, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38165767

RESUMO

Angle-dependent next-generation displays have potential applications in 3D stereoscopic and head-mounted displays, image combiners, and encryption for augmented reality (AR) and security. Metasurfaces enable such exceptional functionalities with groundbreaking achievements in efficient displays over the past decades. However, limitations in angular dispersion control make them unfit for numerous nanophotonic applications. Here, we propose a spin-selective angle-dependent all-dielectric metasurface with a unique design strategy to manifest distinct phase information at different incident angles of light. As a proof of concept, the phase masks of two images are encoded into the metasurface and projected at the desired focal plane under different angles of left circularly polarized (LCP) light. Specifically, the proposed multifunctional metasurface generates two distinct holographic images under LCP illumination at angles of +35 and -35°. The presented holographic displays may provide a feasible route toward multifunctional meta-devices for potential AR displays, encrypted imaging, and information storage applications.

2.
J Fluoresc ; 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38538961

RESUMO

Dye solubilization in microemulsion based on Cetyltrimethylammonium bromide (CTAB) and its modified forms (counter-anions based upon Zn2+, Cu2+ and Fe3+) is comparatively innovative and not explored in existing literature. Here, surfactant with modified counterions (SMCs) were used to study the effects of metal chlorides (ZnCl2, CuCl2 and FeCl3) modifications on the comparative solubilization of Rhodamine-B (RB) by Cetyltrimethylammonium bromide (CTAB) and its modified forms. The solubility of RB in different microemulsions were studied using UV-Visible spectroscopy and phase diagrams of CTAB with modified counter ions CTA+[ZnCl2.Br]- named as CZN-1, CTA+[CuCl2.Br]- named as CCU-1 and CTA+[FeCl3.Br]- named as CFE-1 based upon surfactant with modified counter ions (SMCs). Four different points in microemulsion region of phase diagram were selected with different percentage composition of Smix (surfactant and co-surfactant), oil and RB (taken as water component). The interaction of RB, CCU-1, CFE-1 and CZN-1 within microemulsion environment were studied using Fluorescence spectroscopy. Emission spectra of RB in CCU-1 and CFE-1 based microemulsion confirmed that RB formed complexes with Cu and Fe ions. It was also found that RB was less soluble in CTAB based microemulsion as compared to microemulsions based on SMCs. This novel research study will expose new path for future research work related to microemulsion.

3.
J Fluoresc ; 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38967859

RESUMO

Nitrite ions (NO2-), as one of the leading type-A inorganic-anion, showing significant-effects in the aquatic environment and also to humans health. Whereas, the higher uptake causes detrimental threat to human health leading to various chronic diseases, thus demanding efficient, reliable and convenient method for its monitoring. For this purpose, in the present research study we have fabricated the mimetic nonozyme like catalyst based colorimetric nitrite sensor. The acetic acid capped Zinc Oxide (ZnO) nanosheets (NSs) were introduce as per-oxidase mimetic like catalyst which shows high efficiency towards the oxidative catalysis of colorless tetramethylbenzidine (TMB) to oxidized-TMB (blue color) in the presence of Hydrogen-peroxide (H2O2). The present nitrite ions will stimulate the as formed oxidized-TMB (TMBox), and will caused diazotization reaction (diazotized-TMBox), which will not only decreases the peak intensity of UV-visible peak of TMBox at 652 nm but will also produces another peak at 446 nm called as diazotized-TMBox peak, proving the catalytic reaction between the nitrite ions and TMBox. Further, the prepared colorimetric sensor exhibits better sensitivity with a wider range of concentration (1 × 10-3-4.50 × 10-1 µM), lowest limit of detection (LOD) of 0.22 ± 0.05 nM and small limit of quantification (LOQ) 0.78 ± 0.05 nM having R2 value of 0.998. Further, the colorimetric sensor also manifest strong selectivity towards NO2- as compared to other interference in drinking water system. Resultantly, the prepared sensor with outstanding repeatability, stability, reproducibility, re-usability and its practicability in real water samples also exploit its diverse applications in food safety supervision and environmental monitoring.

4.
Nano Lett ; 23(4): 1195-1201, 2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36622968

RESUMO

Metasurfaces have shown remarkable potential to manipulate many of light's intrinsic properties, such as phase, amplitude, and polarization. Recent advancements in nanofabrication technologies and persistent efforts from the research community result in the realization of highly efficient, broadband, and multifunctional metasurfaces. Simultaneous control of these characteristics in a single-layered metasurface will be an apparent technological extension. Here, we demonstrate a broadband multifunctional metasurface platform with the unprecedented ability to independently control the phase profile for two orthogonal polarization states of incident light over dual-wavelength spectra (ultraviolet to visible). In this work, multiple single-layered metasurfaces composed of bandgap-engineered silicon nitride nanoantennas are designed, fabricated, and optically characterized to demonstrate broadband multifunctional light manipulation ability, including structured beam generation and meta-interferometer implementation. We envision the presented metasurface platform opening new avenues for broadband multifunctional applications including ultraviolet-visible spectroscopy, spatially modulated illumination microscopy, optical data storage, and information encoding.

5.
Small ; 19(19): e2206147, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36755364

RESUMO

Early transition metals based 2D carbides, nitrides and carbonitrides nanomaterials are known as MXenes, a novel and extensive new class of 2D materials family. Since the first accidently synthesis based discovery of Ti3 C2 in 2011, more than 50 additional compositions have been experimentally reported, including at least eight distinct synthesis methods and also more than 100 stoichiometries are theoretically studied. Due to its distinctive surface chemistry, graphene like shape, metallic conductivity, high hydrophilicity, outstanding mechanical and thermal properties, redox capacity and affordable with mass-produced nature, this diverse MXenes are of tremendous scientific and technological significance. In this review, first we'll come across the MXene based nanomaterials possible synthesis methods, their advantages, limitations and future suggestions, new chemistry related to their selected properties and potential sensing applications, which will help us to explain why this family is growing very fast as compared to other 2D families. Secondly, problems that help to further improve commercialization of the MXene nanomaterials based sensors are examined, and many advances in the commercializing of the MXene nanomaterials based sensors are proposed. At the end, we'll go through the current challenges, limitations and future suggestions.

6.
Small ; 19(18): e2207310, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36751959

RESUMO

Hydrogen is emerging as an alternative clean fuel; however, its dependency on freshwater will be a threat to a sustainable environment. Seawater, an unlimited source, can be an alternative, but its salt-rich nature causes corrosion and introduces several competing reactions, hindering its use. To overcome these, a unique catalyst composed of porous sheets of nitrogen-doped NiMo3 P (N-NiMo3 P) having a sheet size of several microns is designed. The presence of large homogenous pores in the basal plane of these sheets makes them catalytically more active and ensures faster mass transfer. The introduction of N and Ni into MoP significantly tunes the electronic density of Mo, surface chemistry, and metal-non-metal bond lengths, optimizing surface energies, creating new active sites, and increasing electrical conductivity. The presence of metal-nitrogen bonds and surface polyanions increases the stability and improves anti-corrosive properties against chlorine chemistry. Ultimately, the N-NiMo3 P sheets show remarkable performance as it only requires overpotentials of 23 and 35 mV for hydrogen evolution reaction, and it catalyzes full water splitting at 1.52 and 1.55 V to achieve 10 mA cm-2 in 1 m KOH and seawater, respectively. Hence, structural and compositional control can make catalysts effective in realizing low-cost hydrogen directly from seawater.

7.
Pak J Pharm Sci ; 36(2): 437-445, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37530151

RESUMO

Plant extracts antiproliferative effects were determined by using mammalian cells along the expression profile of Caspases 3, 8 and the BID gene of the death receptor-induced pathway. Two medicinal plants viz., Turmeric (Curcuma longa) and Amla (Emblica officinalis) extracts were examined for antiproliferative effect through Neutral Red-Dye uptake assay on Vero and MDA-MB 231 cell lines. A reverse transcriptase polymerase chain reaction was used to determine the expression of genes while GAPDH expression was used as an internal control. Expression of BID was up-regulated in methanolic turmeric extract-induced MDA-MB 231 cells while Caspases 3,8 expressions were the same in induced and uninduced MDA-MB 231 cells. Activated BID cleaved into tBID and activated the intrinsic pathway which caused death in methanolic turmeric extract-induced cancerous cells. Ethanolic extracts of turmeric exerted the strongest antiproliferative effects on Vero and methanolic extracts on MDA-MB 231 cells. The morphological studies of cell lines and gene expression analysis of turmeric methanolic extract-treated cells showed activation of apoptosis via converting BID into t-BID (intrinsic pathway) and activating Caspase-3 and Caspase-8 (extrinsic pathway). With the differential cytotoxicity and induction of apoptosis in induced cancer cells in comparison to uninduced cancerous cells, hence turmeric is a natural source of new anti-cancerous compounds.


Assuntos
Caspases , Phyllanthus emblica , Animais , Caspases/metabolismo , Phyllanthus emblica/metabolismo , Curcuma , Linhagem Celular Tumoral , Apoptose , Extratos Vegetais/farmacologia , Extratos Vegetais/análise , Caspase 3/metabolismo , Receptores de Morte Celular , Mamíferos/metabolismo
8.
Biotechnol Appl Biochem ; 69(5): 2195-2204, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34731907

RESUMO

The pncA gene encodes pyrazinamidase enzyme which converts drug pyrazinamide to active form pyrazinoic acid, but mutations in this gene can prevent enzyme activity which leads to pyrazinamide resistance. The cross-sectional study was carried out during 2016-2017 for 12 months. The purpose of the study was to detect mutation at codon 12 and codon 85 in the pncA gene in local multidrug-resistant tuberculosis (MDR-TB) patients by developing a simple molecular test so that disease could be detected timely in the local population. DNA extracted from sputum-cultured samples from MDR-TB patients and subjected to semi-multiplex allele-specific PCR by using self-designed primers against the pncA gene. Among 75 samples, 53 samples were subjected to molecular analysis based on purified DNA quantity and quality. The primers produced 250 and 480 bp fragments, indicating the mutations at codon 12 (aspartate to alanine) and codon 85 (leucine to proline) respectively. MDR-TB was more common in the age group 21-40 years. Fifty-seven percent of samples (n = 30) were found positive for pncA mutations, whereas 43% of samples (n = 23) showed negative results. Thirteen percent of samples (n = 4) had mutations at codon 12 in which aspartate was converted to alanine, and they produced an amplified product of 480 bp. Eighty-seven percent of samples (n = 26) had mutations at codon 85 in which leucine was converted to proline and amplified product size was 250 bp. The mutations were simple nucleotide substitutions. The prevalence of mutations in which leucine was substituted by proline was higher than the mutations in which aspartate was substituted by alanine. A high prevalence of substitution mutation (CTG → CCG; leucine to proline) was detected in MDR-TB cases. Earlier detection of MDR-TB via an effective molecular diagnostic method can control the MDR tuberculosis spread in the population.


Assuntos
Amidoidrolases , Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Adulto , Humanos , Adulto Jovem , Alanina , Amidoidrolases/genética , Amidoidrolases/farmacologia , Antituberculosos/farmacologia , Ácido Aspártico/genética , Ácido Aspártico/farmacologia , Proteínas de Bactérias/genética , Códon , Estudos Transversais , Leucina/genética , Leucina/farmacologia , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/genética , Prolina , Pirazinamida/farmacologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/genética , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia
9.
Chem Soc Rev ; 50(7): 4684-4729, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33621294

RESUMO

Two-dimensional heterostructures (2D HSs) have emerged as a new class of materials where dissimilar 2D materials are combined to synergise their advantages and alleviate shortcomings. Such a combination of dissimilar components into 2D HSs offers fascinating properties and intriguing functionalities attributed to the newly formed heterointerface of constituent components. Understanding the nature of the surface and the complex heterointerface of HSs at the atomic level is crucial for realising the desired properties, designing innovative 2D HSs, and ultimately unlocking their full potential for practical applications. Therefore, this review provides the recent progress in the field of 2D HSs with a focus on the discussion of the fundamentals and the chemistry of heterointerfaces based on van der Waals (vdW) and covalent interactions. It also explains the challenges associated with the scalable synthesis and introduces possible methodologies to produce large quantities with good control over the heterointerface. Subsequently, it highlights the specialised characterisation techniques to reveal the heterointerface formation, chemistry and nature. Afterwards, we give an overview of the role of 2D HSs in various emerging applications, particularly in high-power batteries, bifunctional catalysts, electronics, and sensors. In the end, we present conclusions with the possible solutions to the associated challenges with the heterointerfaces and potential opportunities that can be adopted for innovative applications.

10.
Molecules ; 27(18)2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36144499

RESUMO

Protein corona composition and precise physiological understanding of differentially expressed proteins are key for identifying disease biomarkers. In this report, we presented a distinctive quantitative proteomics table of molecular cell signaling differentially expressed proteins of corona that formed on iron carbide nanoparticles (NPs). High-performance liquid chromatography/electrospray ionization coupled with ion trap mass analyzer (HPLC/ESI-Orbitrap) and MASCOT helped quantify 142 differentially expressed proteins. Among these proteins, 104 proteins showed upregulated behavior and 38 proteins were downregulated with respect to the control, whereas 48, 32 and 24 proteins were upregulated and 8, 9 and 21 were downregulated CW (control with unmodified NPs), CY (control with modified NPs) and WY (modified and unmodified NPs), respectively. These proteins were further categorized on behalf of their regularity, locality, molecular functionality and molecular masses using gene ontology (GO). A STRING analysis was used to target the specific range of proteins involved in metabolic pathways and molecular processing in different kinds of binding functionalities, such as RNA, DNA, ATP, ADP, GTP, GDP and calcium ion bindings. Thus, this study will help develop efficient protocols for the identification of latent biomarkers in early disease detection using protein fingerprints.


Assuntos
Nanopartículas , Coroa de Proteína , Difosfato de Adenosina , Trifosfato de Adenosina , Cálcio , Compostos Inorgânicos de Carbono , Análise por Conglomerados , Guanosina Trifosfato , Compostos de Ferro , Nanopartículas/química , Coroa de Proteína/química , Proteínas/metabolismo , Proteômica/métodos , RNA
11.
Angew Chem Int Ed Engl ; 61(27): e202203876, 2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35426214

RESUMO

High-performance adhesives are of great interest in view of industrial demand. We herein identify a straightforward synthetic strategy towards universal hydrogen-bonded (H-bonded) polymeric adhesives, using a side-chain barbiturate (Ba) and Hamilton wedge (HW) functionalized copolymer. Starting from a rubbery copolymer containing thiolactone derivatives, Ba and HW moieties are tethered as pendant groups via an efficient one-pot two-step amine-thiol-bromo conjugation. Hetero-complementary Ba/HW interactions thus yield H-bonded supramolecular polymeric networks. In addition to an enhanced polymeric network integrity induced by specific Ba/HW association, the presence of individual Ba or HW moieties enables strong binding to a range of substrates, outstanding compared to commercial glues and reported adhesives.


Assuntos
Adesivos , Polímeros , Fenômenos Químicos , Hidrogênio , Ligação de Hidrogênio , Polímeros/química
12.
Environ Res ; 200: 111340, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34043972

RESUMO

Disregarding protective measures when handling pesticides in agricultural production imposes increased health risks and health costs on farmers as well as degrades the natural ecosystem. In Pakistan, where agriculture is the prime occupation in rural communities, there is overwhelming evidence of indiscriminate use of hazardous pesticides by farmers without taking adequate precautions. Using cross-sectional data, we examined personal protection and health costs to vegetable growers due to pesticide exposure and determinants of farmers' pesticide handling practices. The theory of averting behavior was used, and the possible factors affecting farmers' adoption of safety equipment and of disposal methods for pesticide containers were estimated using a logit model. Health effects (P < 0.05) and farmers' protection and health costs (P < 0.01) are found as important determinants of farmers' adoption of safety equipment and of disposal methods for pesticide containers. The mean protection and health cost of pesticide exposure per farmer per vegetable season in 2019 was US $3.60. Analytical outcomes indicate that safe and recommended pesticide handling practices are needed to be introduced through adequate integrated pest management (IPM) training programs and by improving farmers' formal education. Thus, creating awareness through IPM training programs among vegetable growers and enhancing formal education to encourage the adoption of precautionary measures and safe disposal methods for pesticide containers may reduce health risks and health costs. Findings imply that adoption of adequate pesticide handling practices would further help reduce occupational hazards and promote sustainable agriculture in Pakistan.


Assuntos
Exposição Ocupacional , Praguicidas , Agricultura , Estudos Transversais , Ecossistema , Fazendeiros , Custos de Cuidados de Saúde , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Paquistão , Verduras
13.
Small ; 16(47): e2002200, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33140911

RESUMO

Embedding the functional nanostructures into a lightweight nanocarbon framework is very promising for developing high performance advanced electrodes for rechargeable batteries. Here, to realize workable capacity, core-shell (FeSe2 /C) nanostructures are embedded into carbon nanotube (CNT) framework via a facile wet-chemistry approach accompanied by thermally induced selenization. The CNT framework offers 3D continuous routes for electronic/ionic transfer, while macropores provide adequate space for high mass loading of FeSe2 /C. However, the carbon shell not only creates a solid electronic link among CNTs and FeSe2 but also improves the diffusivity of sodium ions into FeSe2 , as well as acts as a buffer cushion to accommodate the volume variations. These unique structural features of CNT/FeSe2 /C make it an excellent host for sodium storage with a capacity retention of 546 mAh g-1 even after 100 cycles at 100 mA g-1 . Moreover, areal and volumetric capacities of 5.06 mAh cm-2 and 158 mAh cm-3 are also achieved at high mass loading 16.9 mg cm-2 , respectively. The high performance of multi-benefited engineered structure makes it a potential candidate for secondary ion batteries, while its easy synthesis makes it extendable to further complex structures with other morphologies (such as nanorods, nanowires, etc.) to meet the high energy demands.

14.
Pak J Pharm Sci ; 33(5(Special)): 2471-2475, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33832892

RESUMO

Cancer chemotherapy can lead to the mycobacterial infections. Tuberculosis has been reported a serious complication in leukemia patients who undergo chemotherapy. The study was focused to find mutations in hupB gene of M. tuberculosis in 50 acute lymphoblastic leukemia (ALL) patients through semi multi complex PCR. A column based DNA isolation method was adopted for DNA isolation. The gene for histone-like protein (hupB [Rv2986c]) of M tuberculosis was amplified to detect two closely related mycobacterial species. Primers M and S (histone like protein HupB) were utilized to generate amplicons of 318 bp and 291 bp for M. tuberculosis and M. bovis, respectively. Out of fifty ALL patients, 21 (42%) were females and 29 (58%) were males. The prevalence of ALL was found higher in males as compared to females. The prevalence of ALL was higher in patients of age group 5-10 years. The results of the amplification showed that, the 318 bp fragment specific for M. tuberculosis was observed in seven samples (14%), while 291 bp fragment specific for M. bovis was not observed in any sample. Children with ALL were found at higher risk for tuberculosis. A risk evaluation of tuberculosis infection must be conducted before managing chemotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteínas de Bactérias/genética , DNA Bacteriano/genética , Histonas/genética , Mycobacterium tuberculosis/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Tuberculose/diagnóstico , Adolescente , Fatores Etários , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Reação em Cadeia da Polimerase Multiplex , Mutação , Paquistão/epidemiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/epidemiologia , Prevalência , Medição de Risco , Fatores de Risco , Resultado do Tratamento , Tuberculose/epidemiologia , Tuberculose/microbiologia , Adulto Jovem
15.
Ann Hum Genet ; 83(4): 214-219, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30891741

RESUMO

Consanguinity has highly complex and multifaceted aspects with sociocultural as well as biological debates on its pros and cons. The biological upshot of consanguinity includes the increased homozygosity, which results in manifold increased risk of genetic disorders at family and population levels. On the other hand, in addition to social, cultural, political, and economic benefits, consanguineous marriages have biological advantages at the population level. The consequence of consanguineous marriages is an upsurge in the number of homozygous diseased individuals with fewer chances of mating and reduced chances of survival, therefore evolutionarily confining the transmission of disease alleles to future generations and encouraging its elimination from a population. Protective effects of consanguinity have also been observed in a few diseases in different populations. Although attractive for many reasons, nonconsanguineous marriages will cause risk alleles to spread throughout the population, making most individuals carriers, and ultimately will resume the production of recessive diseases in subsequent generations. Although consanguinity, from an evolutionary point of view, is beneficial at the population level, it increases the risk of diseases in the very next generation. Presently, there is no treatment for most of the genetic disorders; we cannot opt for consanguinity for long-term benefits. Nonconsanguineous marriages are a better strategy by which we may delay disease manifestation for some generations until science offers a viable solution.


Assuntos
Consanguinidade , Predisposição Genética para Doença , Doenças Genéticas Inatas/diagnóstico , Doenças Genéticas Inatas/genética , Genética Populacional , Humanos , Medição de Risco , Fatores de Risco
16.
Environ Sci Technol ; 53(4): 2161-2170, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30673285

RESUMO

The effective treatment of industrial wastewater to protect freshwater reserves for the survival of life is a primary focus of current research. Herein, a multicomponent Eleocharis-manganese peroxidase enzyme (Eleocharis@MnPE) layered hybrid with high surface area (1200 m2/m3), with a strong synergistic adsorption and catalytic biodegradation (SACB), has been developed through a facile method. A combination of outer porous (Eleocharis) and inner catalytically active (MnPE) components of the hybrid resulted in highly efficient SACB system, evidenced by high removal rate of 15 kg m-3 day-1 (100%) and complete degradation of toxic Orange II (OR) azo dye into nontoxic products (gases and weak acids). The Eleocharis@MnPE layered hybrid efficiently degraded both OR in synthetic wastewater and also other azo dyes (red, pink, and yellow dyes) present in three different textile industrial effluents. For the industrial effluents, these were evidenced by the color disappearance and reduction in biological oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC) of up to 97%, 92%, and 76%, respectively. Furthermore, reduced toxicity of treated wastewater was confirmed by decreased cell toxicity to 0.1%-1% and increased cell viability to 90%. We believe that designing a hybrid system with strong ability of SACB could be highly effective for industrial-scale treatment of wastewater.


Assuntos
Eleocharis , Poluentes Químicos da Água , Adsorção , Compostos Azo , Biodegradação Ambiental , Corantes , Resíduos Industriais , Porosidade , Indústria Têxtil , Eliminação de Resíduos Líquidos , Águas Residuárias
17.
Macromol Rapid Commun ; 40(24): e1900467, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31778270

RESUMO

3D printing of linear and three-arm star supramolecular polymers with attached hydrogen bonds and their nanocomposites is reported. The concept is based on hydrogen-bonded supramolecular polymers, known to form nano-sized micellar clusters. Printability is based on reversible thermal- and shear-induced dissociation of a supramolecular polymer network, which generates stable and self-supported structures after printing, as checked via melt-rheology and X-ray scattering. The linear and three-arm star poly(isobutylene)s PIB-B2 (Mn = 8500 g mol -1 ), PIB-B3 (Mn = 16 000 g mol -1 ), and linear poly(ethylene glycol)s PEG-B2 (Mn = 900 g mol-1 , 8500 g mol -1 ) are prepared and then probed by melt-rheology to adjust the viscosity to address the proper printing window. The supramolecular PIB polymers show a rubber-like behavior and are able to form self-supported 3D printed objects at room temperature and below, reaching polymer strand diameters down to 200-300 µm. Nanocomposites of PIB-B2 with silica nanoparticles (12 nm, 5-15 wt%) are generated, in turn leading to an improvement of their shape persistence. A blend of the linear polymer PIB-B2 and the three-arm star polymer PIB-B3 (ratio ≈ 3/1 mol) reaches an even higher structural stability, able to build free-standing structures.


Assuntos
Nanopartículas/química , Polímeros/química , Impressão Tridimensional , Substâncias Macromoleculares/química , Micelas , Modelos Moleculares , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
18.
Pak J Pharm Sci ; 32(4): 1709-1714, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31608894

RESUMO

Resistance pattern both in newly and previously treated-TB patients and risk factors associated in spread of tuberculosis are investigated in the current study. A total 244 Mycobacterium tuberculosis isolates were used for drug-susceptibility test against four drugs. Environmental risk factors were assessed by using self-designed history proforma. Among 244 TB-isolates, 64% were categorized as MDR-TB in drug-susceptibility test. Male proportion was 51% while 32% belonged to 15-34 years age group and 49% were from city Lahore whereas majority of people (31%) was working on daily wages. Divergent drug-resistance pattern was obtained; RIF (68%), SM (52%), EMB (51%). INH showed only (27%) resistance against first-line anti-TB drug. Drug-resistance prevalence for two drug combination was highest (50%) for (INH+SM) and (INH+EMB) followed by (RIF+SM) (49%) whereas for three drugs combination (INH+RIF+EMB) and (INH+RIF+SM) the prevalence was almost same 50% and 49% respectively while 66% patients were categorized as previously treated and 34% as new TB cases. In drug susceptibility test, 71% were identified as MDR-TB among New TB cases, while 63% were identified as MDR-TB from previously treated cases. Surprisingly DST results displayed that percentage prevalence of MDR-TB both in newly and previously treated cases was almost same.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose/microbiologia , Adolescente , Adulto , Idoso , Antituberculosos/uso terapêutico , Meio Ambiente , Feminino , Humanos , Isoniazida/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mycobacterium tuberculosis/isolamento & purificação , Paquistão/epidemiologia , Prevalência , Rifampina/farmacologia , Fatores de Risco , Tuberculose/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Adulto Jovem
19.
Pak J Pharm Sci ; 32(4): 1717-1722, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31608896

RESUMO

Fungi have been used in modern scientific research due to their high potential for different enzymes production based on genomic features. The great proportion of soil mycoflora represented by saprobic fungi plays an important role in decomposition, thus contribute to the global carbon cycle. Sordaria fimicola strains (n= 61) collected from different environments were evaluated for catalase enzyme activity at first stage. Among all 61 isolates of S. fimicola, five strains viz. S1, S2, N7, N6 and SF13 were found to be most efficient in catalase enzyme activity. The complete catalase gene including exons and introns was amplified and sequenced from the most efficient strains of S. fimicola and then submitted in the NCBI data base under accession numbers KM282183, KM282184, KM282186, KM282185 and KM282182 for strains S1, S2, N7, N6 and SF13 respectively. The significant differences in the genes sequences and theoretically translated proteins were observed for all five strains of S. fimicola. As regards catalase enzyme activity, S. fimicola strains were found comparable to the Aspergillus niger strains, therefore being a saprophytic fungus with short life cycle S. fimicola can become a fungus of choice to produce catalase enzyme at large scale.


Assuntos
Catalase/genética , Catalase/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Sordariales/enzimologia , Filogenia , Mutação Puntual , Microbiologia do Solo
20.
Pak J Pharm Sci ; 32(1(Special)): 397-405, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30852476

RESUMO

.We evaluated the effect of different synthesis methods of solid lipid nanoparticles (SLNs) loaded with bovine serum albumin (BSA) on parameters including particle size, polydispersity index, loading capacity and % entrapment efficiency including release study. We investigated the binary fatty acids mixtures for test protein BSA. Different techniques were used as micro emulsion, ultrasound homogenization and double emulsification-evaporation for the BSA loading of SLNs. With the increase in BSA content from 0-10%, indicated an increase in the size and decrease in polydispersity index. The stability of SLNs loaded with BSA was examined by measuring the zeta potential and all formulations were found to be quite stable. Release study and kinetic models were applied to assess BSA release profile from different formulations of SLNs. The particle size of BSA loaded SLNs was reduced to 89.67 ± 4.88 nm when PEG 6000 and Brij were used as 0.25% and 1.5% of total formulation (F5). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier-transform infrared spectroscopy (FTIR) indicated the chemical stability of BSA which was used to load SLNs in different formulations. SLNs from the combinations of solid and liquid lipids had enhanced the physicochemical properties and permitted controlled release of BSA for up to 10 days. The study also evaluated the addition of polyethylene glycol which reduced the particles size and enhanced % entrapment efficiency. The release of BSA from SLNs was followed zero order rate kinetics and diffusion-controlled. Different mathematical models, i.e., zero order, first order, Higuchi and Korsmeyer-Peppas models were found best fit to BSA release profile of all formulations of SLNs.


Assuntos
Portadores de Fármacos/síntese química , Ácidos Graxos/química , Nanopartículas/química , Preparações Farmacêuticas/administração & dosagem , Soroalbumina Bovina/química , Tecnologia Farmacêutica/métodos , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Cinética , Tamanho da Partícula , Preparações Farmacêuticas/química , Propriedades de Superfície
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