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1.
Small ; : e2402241, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39082423

RESUMO

Future energy loss can be minimized to a greater extent via developing highly active electrocatalysts for alkaline water electrolyzers. Incorporating an innovative design like high entropy oxides, dealloying, structural reconstruction, in situ activation can potentially reduce the energy barriers between practical and theoretical potentials. Here, a Fd-3m spinel group high entropy oxide is developed via a simple solvothermal and calcination approach. The developed (FeCoMnZnMg)3O4 electrocatalyst shows a near equimolar distribution of all the metal elements resulting in higher entropy (ΔS ≈1.61R) and higher surface area. The self-reconstructed spinel high entropy oxide (S-HEO) catalyst exhibited a lower overpotential of 240 mV to reach 10 mA cm-2 and enhanced reaction kinetics (59 mV dec-1). Noticeably, the S-HEO displayed an outstanding durability of 1000 h without any potential loss, significantly outperforming most of the reported OER electrocatalysts. Further, S-HEO is evaluated as the anode catalyst for an anion exchange membrane water electrolyzer (AEMWE) in 1 m, 0.1 m KOH, and DI water at 20 and 60 °C. These results demonstrate that S-HEO is a highly attractive, non-noble class of materials for high active oxygen evolution reaction (OER) electrocatalysts allowing fine-tuning beyond the limits of bi- or trimetallic oxides.

2.
Small ; : e2400913, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38847569

RESUMO

Electrochemical carbon dioxide reduction reaction (ECO2RR) is a promising approach to synthesize fuels and value-added chemical feedstocks while reducing atmospheric CO2 levels. Here, high surface area cerium and sulfur-doped hierarchical bismuth oxide nanosheets (Ce@S-Bi2O3) are develpoed by a solvothermal method. The resulting Ce@S-Bi2O3 electrocatalyst shows a maximum formate Faradaic efficiency (FE) of 92.5% and a current density of 42.09 mA cm-2 at -1.16 V versus RHE using a traditional H-cell system. Furthermore, using a three-chamber gas diffusion electrode (GDE) reactor, a maximum formate FE of 85% is achieved in a wide range of applied potentials (-0.86 to -1.36 V vs RHE) using Ce@S-Bi2O3. The density functional theory (DFT) results show that doping of Ce and S in Bi2O3 enhances formate production by weakening the OH* and H* species. Moreover, DFT calculations reveal that *OCHO is a dominant pathway on Ce@S-Bi2O3 that leads to efficient formate production. This study opens up new avenues for designing metal and element-doped electrocatalysts to improve the catalytic activity and selectivity for ECO2RR.

3.
Chemistry ; 30(42): e202401417, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-38970532

RESUMO

An asymmetric mixed valence fluorophore with two different electron rich termini was investigated as a dual-role active material for electrochromism and electrofluorochromism. The fluorescence quantum yield (Φfl) and emission wavelength of the fluorophore were dependent on solvent polarity. The quantum yield of the material in an electrolyte gel, on a glass substrate and in a device was 40 %, 20 % and 13 % respectively. The fluorophore further underwent two near-simultaneous electrochemical oxidations. The first oxidation resulted in a 1000 nm red shift in the absorption to broadly absorb in the NIR, corresponding to the intervalence charge transfer (IVCT). Whereas the second oxidation led to a perceived green color at 715 nm with the extinction of the NIR absorbing IVCT. Owing to the dissymmetry of the fluorophore along with its two unique oxidation sites, the IVCT gives rise to a mixed valence transfer charge (MVCT). The coloration efficiency of the fluorophore in both solution and a device was 1433 and 200 cm2 C-1, respectively. The fluorescence intensity could be reversibly modulated electrochemically. The photoemission intensity of the fluorophore was modulated with applied potential in an operating electrochromic/electrofluorochromic device. Both the dual electrochromic and the electrofluorochromic behavior of the fluorophore were demonstrated.

4.
Luminescence ; 39(3): e4706, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38483095

RESUMO

Inorganic cesium lead halide perovskites have evoked wide popularity because of their excellent optoelectronic properties, high photoluminescence (PL) quantum yield (PLQY), and narrowband emission. Here, cesium lead bromide (CsPbBr3 ) quantum dots (QDs) were synthesized via the ligand-assisted re-precipitation method. Post-synthesis treatment of CsPbBr3 QDs using antimony tribromide improved the PL stability and optoelectronic properties of the QDs. In addition, the PLQY of the post-treated sample was enhanced to 91% via post-treatment, and the luminescence observed was maintained for 8 days. The post-synthesis treatment ensured defect passivation and improved the stability of CsPbBr3 perovskite QDs. High-resolution transmission electron microscopy revealed the presence of more ordered, uniform-sized CsPbBr3 QDs after post-synthesis treatment, and the uniformity of the sample improved as the day passed. The formation of a mixed crystal phase was observed from X-ray diffraction in both as-synthesized, as well as post-treated QDs samples with the possibility of a polycrystalline nature in the post-treated CsPbBr3 QDs as per the selected area electron diffraction pattern. The X-ray photoelectron spectroscopy spectra confirmed the presence of antimony and the possibility of defect passivation in the post-treated samples. These QDs can act as potential candidates in various optoelectronic applications such as photodetectors and light-emitting diodes due to their high PLQY and longer lifetime.


Assuntos
Antimônio , Brometos , Compostos de Cálcio , Óxidos , Pontos Quânticos , Titânio , Césio
5.
Indian J Microbiol ; 64(3): 1379-1383, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39282179

RESUMO

Multidrug-resistant Klebsiella pneumoniae (MDR-KP) infections have become a major global issue in the healthcare sector. Alternative viable tactics for combating bacterial infections, such as the use of bacteriophages, can be considered. One of the major challenges in phage therapy is the emergence of phage-resistant bacteria. This study isolated bacteriophages from water and soil samples against MDR-KP isolates. Susceptible bacterial hosts were exposed to phages at different concentrations and prolonged durations of time to obtain phage-resistant survivors. Phenotypic changes such as changes in growth rates, biofilm formation ability, antibiotic sensitivity patterns, and outer membrane proteins (OMPs) profiling of the survivors were studied. Our findings indicate that the phage ØKp11 and ØKp26 survivors had reduced growth rates and biofilm formation ability, altered antibiotic sensitivity patterns, and reduced OMPs expression compared with the parent MDR-KP002 isolate. These results suggest that the alternations in the bacterial envelope result in phenotypic phage resistance among MDR bacterial isolates. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-024-01217-6.

6.
Environ Monit Assess ; 196(1): 57, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38110690

RESUMO

In the hilly terrain of Nepal, springs are the main source of drinking water. With the increasing population, rapid urbanization, and unabated climate change, springs are under the risk of survival. There is increasing evidence that springs in the mid-hills of Nepal are drying up, or are reducing in discharge, or are deteriorating by water quality. As a result, local communities are facing unprecedented water stress. On this background scenario, assessment of water quality of the springs in the Marin Watershed of Sindhuli district of Nepal was carried out in this study. Spring water samples were collected during the pre-monsoon and post-monsoon of 2020 and their hydrochemistry was analyzed. Further, springs' discharge was measured in situ and their criticality and sustainability were studied through community interaction. Results have revealed seasonal variation in spring discharge and spring water quality. Out of 39 flowing springs, water quality of 13, 8, and 6 springs, respectively, was very poor, poor, and unsuitable for drinking in the pre-monsoon. The count of springs with very poor, poor, and unsuitable drinking water quality during the post-monsoon was 8, 3, and 1, respectively. Occurrence of pathogenic bacteria (Escherichia coli) was identified in five spring samples which makes the spring water unsafe for drinking. Again, out of 51 springs studied, 12 are already dried up, and another 12 of the 39 flowing springs have become seasonal with very low discharge (0.03-0.07 L/s). The study highlights and emphasizes the need to protect the flowing springs and rejuvenate the dying springs of the Himalaya and of other parts of the world.


Assuntos
Água Potável , Qualidade da Água , Himalaia , Nepal , Monitoramento Ambiental/métodos
7.
Clin Exp Dermatol ; 46(1): 50-57, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32516443

RESUMO

BACKGROUND: Psoriasis is a T helper cell-mediated chronic immune-mediated inflammatory disease affecting mainly the skin, although systemic pathological effects are also observed. Cytokine-mediated interaction between T lymphocytes and keratinocytes lead to excessive proliferation of keratinocytes, which in turn leads to formation of a proinflammatory milieu and finally to psoriatic plaque formation. AIM: To measure interleukin (IL)-9, IL-17 and vascular endothelial growth factor (VEGF) levels in patients with psoriasis compared with controls, and to evaluate the effect of methotrexate (MTX) monotherapy on the aforesaid cytokine levels in psoriasis. METHODS: This cohort study included 54 patients with psoriasis and 54 age- and sex-matched healthy controls (HCs). IL-9, IL-17 and VEGF levels were measured by using commercially available ELISA kits. Patients with psoriasis who were on MTX monotherapy were followed up for a period of 3 months. RESULTS: Patients with psoriasis had increased levels of IL-9, IL-17 and VEGF at baseline, compared with the HC group. After 3 months of MTX monotherapy, Psoriasis Area Severity Index (PASI), Dermatology Life Quality Index (DLQI) and levels of cytokines (IL-9, IL-17 and VEGF) were significantly decreased compared with baseline. PASI and DLQI at baseline also showed a positive correlation with IL-9, IL-17 and VEGF. CONCLUSION: Our results suggest the existence of a proinflammatory milieu in psoriasis, with increased levels of IL-9, IL-17 and the proangiogenic growth factor VEGF, showing an increasing trend with increasing disease severity and impaired quality of life (QoL). MTX treatment helps to reduce levels of IL-9, IL-17 and VEGF, thereby limiting disease progression and improving QoL in psoriasis.


Assuntos
Inflamação/fisiopatologia , Interleucina-9/sangue , Neovascularização Patológica/fisiopatologia , Psoríase/imunologia , Fator A de Crescimento do Endotélio Vascular/sangue , Adulto , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Humanos , Interleucina-17/sangue , Interleucina-9/fisiologia , Masculino , Pessoa de Meia-Idade , Neovascularização Patológica/sangue , Gravidade do Paciente , Psoríase/sangue , Psoríase/tratamento farmacológico , Psoríase/fisiopatologia , Qualidade de Vida , Valores de Referência
8.
J Phys Chem A ; 124(26): 5297-5305, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32520543

RESUMO

Photoinduced electron transfer across an organic capsular wall between excited donors and ground-state acceptors is established to occur with rate constants varying in the range 0.32-4.0 × 1011 s-1 in aqueous buffer solution. The donor is encapsulated within an anionic supramolecular capsular host, and the cationic acceptor remains closer to the donor separated by the organic frame through Coulombic attraction. Such an arrangement results in electron transfer proceeding without diffusion. Free energy of the reaction (ΔG°) and the rate of electron transfer show Marcus relation with inversion. From the plot, λ and Vel were estimated to be 1.918 and 0.0058 eV, respectively. Given that the donor remains within the nonpolar solvent-free confined space, and there is not much change in the environment around the acceptor, the observed λ is believed to be because of "internal" reorganization rather than "solvent" reorganization. A similarity exists between the capsular assembly investigated here and glass and crystals at low temperature where the medium is rigid. The estimated electronic coupling (Vel) implies the existence of interaction between the donor and the acceptor through the capsular wall. Existence of such an interaction is also suggested by 1H NMR spectra. Results of this study suggest that molecules present within a confined space could be activated from outside. This provides an opportunity to probe the reactivity and dynamics of radical ions within an organic capsule.

9.
Crit Rev Microbiol ; 45(5-6): 701-711, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31775552

RESUMO

Increasing levels of resistance to antimicrobial agents have created chaos in the health sector, with several infections not responding to antibiotic treatments. Search for alternative strategies has looked at bacteriophages as potential therapeutics and in the last couple of years. There are reports of phages being successfully used to treat life-threatening infections. Phages are also mobile elements that exchange genes between and within different bacterial species and account significantly for strain differences across and within a species. A gap in metagenomics analysis and conservative methods of detection have failed to give an accurate account of the role of bacteriophages in antimicrobial resistance. Recent studies have focussed on the role of bacteriophages in the adaptation of pathogens to new hosts and the emergence of multidrug-resistance, which are a significant concern against phage therapy. This article presents a comprehensive account of weighing the odds of phage therapy verses phage-mediated antimicrobial resistance.


Assuntos
Bactérias/genética , Infecções Bacterianas/microbiologia , Bacteriófagos/genética , Farmacorresistência Bacteriana , Animais , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/virologia , Infecções Bacterianas/terapia , Bacteriófagos/fisiologia , Humanos , Terapia por Fagos , Transdução Genética
10.
J Phys Chem A ; 123(42): 9123-9131, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31542924

RESUMO

Phosphorescence from pyrene especially at room temperature is uncommon. This emission was recorded utilizing a supramolecular organic host and the effect due to the heavy atom. Poor intersystem crossing from S1 to T1, small radiative rate constant from T1, and large rate constant for oxygen quenching hinder the phosphorescence of aromatic molecules at room temperature in solution. In this study, these limitations are overcome by encapsulating a pyrene molecule within a water-soluble capsule (octa acid, OA) and purging with xenon. While OA suppressed oxygen quenching, xenon enabled the intersystem crossing from S1 to T1 and radiative process from T1 to S0 through the well-known heavy atom effect. The close interaction facilitated between the pyrene and the heavy atom perturber xenon in the three-component supramolecular assembly (OA, pyrene, and xenon) resulted in phosphorescence from pyrene. Computational modeling and NMR studies supported the postulate that pyrene and more than one molecule of xenon are present within a confined space of the OA capsule.

11.
J Phys Chem A ; 123(24): 5061-5071, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31140802

RESUMO

Ultrafast spectroscopy reveals the effects of confinement on the excited-state photoisomerization dynamics for a series of alkyl-substituted trans-stilbenes encapsulated in the hydrophobic cavity of an aqueous supramolecular organic host-guest complex. Compared with the solvated compounds, encapsulated trans-stilbenes have broader excited-state absorption spectra, excited-state lifetimes that are 3-4 times longer, and photoisomerization quantum yields that are 1.7-6.5 times lower in the restricted environment. The organic capsule disrupts the equilibrium structure and restricts torsional rotation around the central C═C double bond in the excited state, which is an important motion for the relaxation of trans-stilbene from S1 to S0. The location and identity of alkyl substituents play a significant role in determining the excited-state dynamics and photoisomerization quantum yields by tuning the relative crowding inside the capsule. The results are discussed in terms of distortions of the ground- and excited-state potential energy surfaces, including the topology of the S1-S0 conical intersection.

12.
Indian J Med Res ; 149(2): 290-294, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31219097

RESUMO

To understand antimicrobial resistance (AMR) patterns and mechanisms of horizontal gene transfer in human-associated environments is essential to AMR surveillance. Gram-negative bacteria (1122 isolates) from food-animal environments were characterized for antimicrobial susceptibility and AMR genes. Seventy five per cent of the isolates (837 of 1122) were resistant to at least one of the antibiotics tested. Resistance to more than three groups of antimicrobials (multidrug resistance) was observed in 43 isolates with most often encountered (12 of 43) resistance to ß-lactams, tetracycline, quinolones and nitrofurantoin. The profile of frequently reported plasmid-mediated resistance gene in these isolates was determined. The mobility of these elements as plasmids or phages was examined. The blaCTX-M gene was present in the plasmid of 61 per cent and packed in induced phage fractions in 72 per cent of the isolates and blaTEMin 69 per cent phage fractions compared to 15 per cent presence in the plasmid.


Assuntos
Infecções Bacterianas/epidemiologia , Farmacorresistência Bacteriana/genética , Microbiologia Ambiental , beta-Lactamases/genética , Animais , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/genética , Infecções Bacterianas/microbiologia , Transferência Genética Horizontal/genética , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/patogenicidade , Humanos , Índia/epidemiologia , Testes de Sensibilidade Microbiana , Plasmídeos/genética
13.
Indian J Med Res ; 149(2): 232-239, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31219088

RESUMO

Background & objectives: The resistance to antibiotics in pathogenic bacteria has increased at an alarming rate in recent years due to the indiscriminate use of antibiotics in healthcare, livestock and aquaculture. In this context, it is necessary to monitor the antibiotic resistance patterns of bacteria isolated from the environmental samples. This study was conducted to determine the phenotypic and genotypic profile of antimicrobial resistance in Gram-negative bacteria isolated from environmental samples. Methods: Two hundred and fifty samples were collected from different sources, viz. fish and fishery products (99), livestock wastes (81) and aquaculture systems (70), in and around Mangaluru, India. Isolation, identification and antimicrobial profiling were carried out as per standard protocols. The isolates were screened for the presence of resistance genes using PCR. Results: A total of 519 Gram-negative bacteria comprising Escherichia coli (116), Salmonella spp. (14), Vibrio spp. (258), Pseudomonas spp. (56), Citrobacter spp. (26) and Proteus spp. (49) were isolated and characterized from 250 samples obtained from different sources. A total of 12 antibiotics were checked for their effectiveness against the isolates. While 31.6 per cent of the isolates were sensitive to all the antibiotics used, 68.4 per cent of the isolates showed resistance to at least one of the antibiotics used. One-third of the isolates showed multidrug resistance. Maximum resistance was observed for ampicillin (43.4%), followed by nitrofurantoin (20.8%). Least resistance was seen for carbapenems and chloramphenicol. PCR profiling of the resistant isolates confirmed the presence of resistance genes corresponding to their antibiotic profile. Interpretation & conclusions: This study results showed high rate of occurrence of antimicrobial resistance and their determinants in Gram-negative bacteria isolated from different environmental sources.


Assuntos
Antibacterianos/efeitos adversos , Farmacorresistência Bacteriana/genética , Microbiologia Ambiental , Bactérias Gram-Negativas/genética , Antibacterianos/uso terapêutico , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/patogenicidade , Humanos , Índia/epidemiologia , Testes de Sensibilidade Microbiana
14.
Small ; 14(16): e1704005, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29573555

RESUMO

Exploring the ordering mechanism and dynamics of self-assembled block copolymer (BCP) thin films under confined conditions are highly essential in the application of BCP lithography. In this study, it is aimed to examine the self-assembling mechanism and kinetics of silicon-containing 3-arm star-block copolymer composed of polystyrene (PS) and poly(dimethylsiloxane) blocks as nanostructured thin films with perpendicular cylinders and controlled lateral ordering by directed self-assembly using topographically patterned substrates. The ordering process of the star-block copolymer within fabricated topographic patterns with PS-functionalized sidewall can be carried out through the type of secondary (i.e., heterogeneous) nucleation for microphase separation initiated from the edge and/or corner of the topographic patterns, and directed to grow as well-ordered hexagonally packed perpendicular cylinders. The growth rate for the confined microphase separation is highly dependent upon the dimension and also the geometric texture of the preformed pattern. Fast self-assembly for ordering of BCP thin film can be achieved by lowering the confinement dimension and also increasing the concern number of the preformed pattern, providing a new strategy for the design of BCP lithography from the integration of top-down and bottom-up approaches.

15.
Phys Chem Chem Phys ; 20(38): 24821-24831, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30229767

RESUMO

The effect of methylene blue (MB) modified multiwall carbon nanotubes (MWNTs) on the nucleation and morphology of polyvinylidene fluoride (PVDF) in comparison with the effect of MWNTs was systematically assessed by DSC, 13C NMR, FT-IR, TEM, WAXS and SAXS analysis. TEM analysis of ultra-microtomed samples revealed that MB modification enhanced the dispersibility of MWNTs in PVDF. Further, the nanocomposites were subjected to mechanical rolling and the synergistic effect of processing and fillers on the PVDF morphology (before and after rolling) at different length scales was studied. Both FT-IR and WAXS analyses suggested that mechanical rolling transforms α-PVDF to ß-PVDF (ca. 88%). TEM and two-dimensional WAXS analyses revealed that the MWNTs and ß-crystallites are oriented preferentially along the rolling direction and the degree of orientation is not influenced by the fillers suggesting that crystallite orientation is fully controlled by mechanical rolling. On the other hand, ß-lamellae showed perpendicular orientation with respect to the rolling direction. Unlike ß-crystallites, the ß-lamellar morphology and orientation are highly governed by the fillers as evident from SAXS analysis. Using MWNTs and the MWNT-MB π-complex, we demonstrate that the ß-lamellar morphology and degree of orientation are controlled by the extent of interaction of fillers with PVDF. Interestingly, both ß-lamellar morphology and degree of orientation correlate well with the mechanical properties of the rolled PVDF. More specifically, the dynamic storage modulus of the samples in the rolling direction increases with increasing ß-lamellar morphology and degree of orientation. The present work demonstrates that the polymer-filler interaction plays a crucial role in regulating the processed polymer morphology and can be tuned by appropriately modifying the surface of fillers through either covalent or non-covalent interactions.

16.
Lett Appl Microbiol ; 67(1): 9-14, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29675838

RESUMO

The resistance determinant blaCTX-M has many variants and has been the most commonly reported gene in clinical isolates of extended spectrum beta-lactamase producing Escherichia coli. Phages have been speculated as potential reservoirs of resistance genes and efficient vehicles for horizontal gene transfer. The objective of the study was to determine the prevalence and characterize bacteriophages that harbour the resistance determinant blaCTX-M . Escherichia coli specific bacteriophages were isolated from 15 samples including soil and water across Mangaluru, India using bacterial hosts that were sensitive to ß-lactams. Phenotypic and genotypic characterization based on plaque morphology, host range, restriction fragment length polymorphism (RFLP), presence of blaCTX-M and electron microscopy was performed. Of 36 phages isolated, seven were positive for Group 1 of blaCTX-M . Based on host range and RFLP pattern, the seven phages were classified into four distinct groups, each harbouring a variant of blaCTX-M . Five phages were T4-like Myoviridae by electron microscopy which was further confirmed by polymerase chain reaction (PCR) for T4 specific gp14. Generalized transduction of the CTX-M gene from these phages was also observed. The high prevalence (20%) of this gene blaCTX-M in the phage pool confirms the significant role of Myoviridae members, specifically T4-like phages in the dissemination of this resistance gene. SIGNIFICANCE AND IMPACT OF THE STUDY: The CTX-M gene that confers resistance to Beta-lactam class of drugs is widespread and diverse. Understanding mechanisms of antimicrobial resistance transfer is a key to devise methods for controlling it. Few studies indicate that bacteriophages are involved in the transfer of this gene but the type of phages involved and the degree of involvement remains to be explored. Our work has been able to identify the class of phages and the magnitude of involvement in the dissemination of this gene.


Assuntos
Antibacterianos/farmacologia , Bacteriófago T4/genética , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Transferência Genética Horizontal/genética , beta-Lactamases/genética , beta-Lactamas/farmacologia , Bacteriófago T4/classificação , Bacteriófago T4/isolamento & purificação , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Humanos , Índia , Plasmídeos/genética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Microbiologia do Solo , Microbiologia da Água
17.
Langmuir ; 33(34): 8428-8435, 2017 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-28817284

RESUMO

Herein, we aim to develop a facile method for the fabrication of mesoporous polystyrene (PS) films with controlled porosity and pore size by solvent annealing. A PS polymer film is solvent-annealed using N,N-dimethyl formamide (DMF) vapor for the development of phase separation, followed by rapidly cooling to the preset cryogenic temperature. Subsequently, a nonsolvent (methanol) is introduced to extract the crystalline DMF from the DMF-swollen PS, giving mesoporous PS with a network structure after the removal of DMF. The porosity of the mesoporous PS films can be controlled by the degree of swelling. Most interestingly, the phase separation between PS and DMF at the thin-film state under solvent annealing can be regulated by the annealing time through the spinodal decomposition, giving the development of nanonetwork structure with controlled structural features (i.e., framework size and interframework spacing) at invariant porosity. Consequently, after the removal of DMF, mesoporous PS films with controlled porosity and pore size can be obtained and then used as a template for the fabrication of a variety of nanoporous inorganics by templated syntheses, such as nanoporous SiO2, TiO2, and Ni, providing a cost-effective way to fabricate a range of nanoporous materials with controlled porosity and pore size as well as large specific surface area for aimed applications.

18.
Org Biomol Chem ; 15(5): 1115-1121, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28101551

RESUMO

This comprehensive study portrays that p-toluenesulfonic acid is a more efficient catalyst for the reaction between p-quinones and 3,4-dihydro-2H-pyran, than the Lewis acids. The products were accomplished by the Diels-Alder cycloaddition reaction and their mechanistic pathways have been formulated. The impact of C2 and C2,5 substituents of the p-quinones on the cycloaddition reaction has been explored. Remarkably, it is the first report to explore this kind of in situ generated diene for the Diels-Alder cycloaddition reaction.

19.
Med J Armed Forces India ; 73(1): 104, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-30510356

RESUMO

[This retracts the article DOI: 10.1016/j.mjafi.2012.04.010.].

20.
J Minim Access Surg ; 12(4): 325-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27251818

RESUMO

AIM: Laparoscopic cholecystectomy (LC) is considered the 'gold standard' intervention for gall bladder (GB) diseases. However, to avoid serious biliovascular injury, conversion is advocated for distorted anatomy at the Calot's triangle. The aim is to find out whether our technique of laparoscopic modified subtotal cholecystectomy (LMSC) is suitable, with an acceptable morbidity and outcome. PATIENTS AND METHODS: A retrospective analysis of prospectively collected data of 993 consecutive patients who underwent cholecystectomy was done at a large District General Hospital (DGH) between August 2007 and January 2015. The data are as follows: Patient's demographics, operative details including intra- and postoperative complications, postoperative stay including follow-up that was recorded and analysed. RESULTS: A total of 993 patients (263 males and 730 female) were included. The median age was 52*(18-89) years. Out of the 993 patients, 979 (98.5%) and 14 (1.5%) were listed for laparoscopic and open cholecystectomy, respectively. Of the 979 patients, 902 (92%) and 64 (6.5%) patients underwent LC ± on-table cholangiography (OTC) and LMSC ± OTC, respectively, with a median stay of 1* (0-15) days. Of the 64 patients, 55 (86%) had dense adhesions, 22 (34%) had acute inflammation, 19 (30%) had severe contraction, 12 (19%) had empyema, 7 (11%) had Mirizzi's syndrome and 2 (3%) had gangrenous GB. The mean operative time was 120 × (50-180) min [Table 1]. Six (12%) patients required endoscopic retrograde cholangiopancreatography (ERCP) postoperatively, and there were four (6%) readmissions in a follow-up of 30 × (8-76) months. The remaining 13 (1.3%) patients underwent laparoscopic cholecystectomy converted to an open cholecystectomy. The median stay for open/laparoscopic cholecystectomy converted to open cholecystectomy was 5 × (1-12) days. CONCLUSION: Our technique of LMSC avoided conversion in 6.5% patients and believe that it is feasible and safe for difficult GBs with a positive outcome.

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