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1.
Homeopathy ; 108(2): 121-127, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30616251

RESUMO

BACKGROUND: For the study of homeopathic medicines in proper perspective, emerging techniques in material science are being used. Vibrational spectroscopy is one such tool for providing information on different states of hydrogen bonding as an effect of potentization. The associated change in electrical properties is also correlated with this effect. OBJECTIVE: From the vibrational spectra, the changes in hydrogen bonding due to dilution followed by unidirectional vigorous shaking (together termed potentization) of 91% ethanol and two homeopathic medicines Chininum purum and Acidum benzoicum have been studied. The aim was to correlate the result with the change in the electrical properties of the system. METHODS: Raman spectroscopy was used to study the vibrational spectra. A U-shaped glass tube (electrochemical cell), where one arm contained bi-distilled water and the other arm alcohol/homeopathic medicine (the arms being separated by a platinum foil), was used to measure the voltage generated across two symmetrically placed platinum electrodes. RESULTS: For all samples, it was observed that potentization affected the intensity of OH stretching bands at the frequencies 3240 cm-1, 3420 cm-1 and 3620 cm-1, corresponding to strong hydrogen bond, weak hydrogen bond and broken hydrogen bond, respectively. With the increase in potency, in the presence and absence of the two medicines in ethanol, the number of OH groups linked by strong hydrogen bonds decreased, while the number of OH groups with weak hydrogen bonds increased. With the increase in potentization, the number of OH groups with broken hydrogen bonds showed a difference in the presence and absence of the medicine.The voltage measurements for ethanol show that, with succussion, the magnitude of voltage increased with the two medicines at lower potencies, but not at higher potency where the voltage is lower. Acidum benzoicum, which is acidic in nature, had higher voltage values (113mV, 130 mV and 118 mV at 6C, 30C and 200C, respectively), compared with Chininum purum, which is basic in nature (20 mV, 85 mV and 65 mV at 6C, 30C and 200C, respectively). CONCLUSION: The experimental results indicate a correlation between the vibrational and electrical properties of the homeopathic medicines Acidum benzoicum and Chininum purum at different potencies.


Assuntos
Homeopatia , Materia Medica/química , Condutividade Elétrica , Humanos , Análise Espectral Raman
2.
Langmuir ; 34(43): 12702-12712, 2018 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-30289725

RESUMO

Because of the superior optical and electrical properties, copper-impregnated size tuneable high-temperature stable manganese dioxide semiconductor quantum dots (SQDs) have been successfully synthesized by a modified chemical synthesis technique. Their size-dependent dielectric properties, semiconducting properties, and current-voltage ( I- V) characteristics have been investigated. X-ray diffraction pattern and Raman spectra confirmed that the required phase is present. Because of the different sintering temperature tuneable size of SQDs has been found and confirmed by high-resolution transmission electron microscopy. The band gap energy of the material is found to be 1.25-1.67 eV, measured from Tauc plot using UV-vis absorbance spectrum and their semiconducting properties have been confirmed by the non linear current-voltage ( I- V) behavior. Most intense green emission peak of photoluminescence (PL) spectroscopy confirms the oxygen vacancy defect state. The stoke shifting of Raman spectra, UV absorption, and PL emission are the footprint of quantum confinement effect. Incorporation of a little amount of Cu in tetragonal hollandite structure of α-MnO2 generates strain within that structure. This leads to create sufficient crystal defect state as well as rise in dielectric constant accompanied with low dielectric loss and higher ac conductivity. All these highly desirable properties make the SQDs a potential candidate for developing multifunctional photo-electronic devices. Owing to the tuneable band gap and electronic transport of the SQDs, we realized that the controllable size paves the way for designing SQDs possessing unique properties for optical and electronic device applications. Using this material as a high dielectric separator, a high-performance supercapacitor has been successfully fabricated which can light up 15 light-emitting diodes for 47 min 23 s after charging them only for 30 s.

3.
Homeopathy ; 107(2): 130-136, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29767830

RESUMO

BACKGROUND: We report the effects of nanoparticles in homeopathic preparations of copper salts on the electrical properties of polymer film. Previous work showed that the incorporation of metal-derived homeopathic medicines increases the dielectric constant and alternating current (AC) conductivity of an electroactive polymer film that is commonly used as a capacitor in the electronic industry.We report here the effect of dilution of one homeopathic medicine, Cuprum arsenicosum (CuAs), at 200C potency on the electrical properties of the polymer film of poly(vinylidene fluoride-co-hexafluoropropylene). METHODS: CuAs 200c was incorporated in the film by the solution casting method. The electrical characteristics were measured at different frequencies using an inductance, capacitance, and resistance meter. Fourier transform infrared spectroscopy (FTIR) was performed to detect phase change in the polymer film due to the incorporation of CuAs. Morphology and particle size were studied using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy. RESULTS: At 10 kHz frequency, both dielectric constant and AC conductivity increased approximately 18 times for the polymer film when incorporated with 2 mL CuAs at 200C potency. FTIR indicated the increase in conducting phase, while FESEM and EDX confirmed the presence of spherical CuAs particles. CONCLUSION: The incorporation of CuAs in the electroactive polymer film enhances the conductivity and dielectric constant. We conclude that these changes arise from the change in phase of the polymer film, and because of the presence of two different metals that affects the interfacial polarization.


Assuntos
Arsenitos/química , Cobre/química , Homeopatia , Hidróxidos/química , Nanopartículas/química , Técnicas de Diluição do Indicador , Polivinil
4.
Phys Chem Chem Phys ; 17(2): 1368-78, 2015 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-25424552

RESUMO

A simple and low cost in situ process has been developed to synthesize Fe2O3-Co3O4 nanoparticles (NPs) loaded poly(vinylidene fluoride) (PVDF) thin films. The electroactive ß phase nucleation mechanism and the dielectric properties of the films have been investigated by X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry and using an LCR meter. Results confirmed that the electroactive ß phase crystallization in the PVDF matrix is due to the fast nucleating or catalytic effect of the in situ NPs. Homogenous dispersion of in situ Fe2O3-Co3O4 NPs in the polymer matrix leads to strong interfacial interaction between the NPs and the polymer resulting in enhanced ß phase nucleation in PVDF and a large dielectric constant of the thin films. The observed variation in the electroactive ß phase nucleation by NPs (Fe2O3-Co3O4) and the dielectric properties of the thin films have been explained on the basis of surface charge, size, geometrical shape and extent of agglomeration of the NPs in the polymer matrix.

5.
Phys Chem Chem Phys ; 17(19): 13082-91, 2015 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-25915166

RESUMO

A facile and low cost synthesis of Ni(OH)2 nanobelt (NB) modified electroactive poly(vinylidene fluoride) (PVDF) thin films with excellent dielectric properties has been reported via in situ formation of Ni(OH)2 NBs in the PVDF matrix. The formation and morphology of the NBs are confirmed by UV-visible spectroscopy and field emission scanning electron microscopy respectively. A remarkable improvement in electroactive ß phase nucleation (∼82%) and the dielectric constant (ε ∼ 3.1 × 10(6) at 20 Hz) has been observed in the nanocomposites (NCs). The interface between the NBs and the polymer matrix plays a crucial role in the enhancement of the electroactive ß phase and the dielectric properties of thin films. Strong interaction via hydrogen bonds between Ni(OH)2 NBs and the PVDF matrix is the main reason for enhancement in ß phase crystallization and improved dielectric properties. The NC thin films can be utilized for potential applications as high energy storage devices like supercapacitors, solid electrolyte batteries, self-charging power cells, piezoelectric nanogenerators, and thin film transistors and sensors.


Assuntos
Hidróxidos/química , Nanocompostos/química , Níquel/química , Polivinil/química , Cristalização , Impedância Elétrica
6.
J Integr Med ; 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-39013752

RESUMO

OBJECTIVE: Pharmacopoeias regulate the manufacture of potentised pharmaceutical preparations used in different branches of complementary and integrative medicine. The physicochemical properties and biological activity of these preparations are often investigated in preclinical research, yet no guidelines for experimental research currently exist in this area. The present PrePoP guidelines aim to provide recommendations to promote high-quality, statistically sound, and reproducible preclinical research on potentised preparations. METHODS: Input was gathered from researchers nominated by the relevant scientific societies using a simplified Delphi consensus approach covering the most relevant aspects of basic research methodology in the field including appropriate controls, sample preparation and handling, and statistics. After three rounds of feedback, a consensus was finally reached on the most important aspects and considerations for conducting high-quality research on potentised preparations. RESULTS: We present a series of recommendations on a range of topics including experimental controls, system stability, blinding and randomisation, environmental influences, and procedures for the preparation of potentised samples and controls, and we address some specific challenges of this research field. CONCLUSION: This expert consensus process resulted in a robust set of methodological guidelines for research on potentised preparations and provides a valuable framework that will inform and improve the quality of subsequent research in this emerging field. PLEASE CITE THIS ARTICLE AS: Tournier AL, Bonamin LV, Buchheim-Schmidt S, Cartwright S, Dombrowsky C, Doesburg P, Holandino C, Kokornaczyk MO, van de Kraats EB, López-Carvallo JA, Nandy P, Mazón-Suástegui JM, Mirzajani F, Poitevin B, Scherr C, Thieves K, Würtenberger S, Baumgartner S. Scientific guidelines for preclinical research on potentised preparations manufactured according to current pharmacopoeias-the PrePoP guidelines. J Integr Med. 2024; Epub ahead of print.

7.
J Environ Monit ; 13(6): 1709-15, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21566830

RESUMO

The presence of engineered nanoparticles is continuously increasing in our environment and causing potential risks to the ecosystem. Researchers from various fields report many articles on the effects of different nanoparticles on plants, animals and microorganisms. Here we have studied for the first time the effect of nano mullite (NMu) and their metal- amended derivatives on the growth of mung bean plants. Results shows that the metal- amended NMu exerts adverse effects on the growth and biomass production of plants compared to NMu. For toxicity studies, we measured the germination index and relative root elongation, while leakage of electrolytes and root oxidizability were measured to study the effect of NMu on mung bean seeds and seedling tissues. Translocation and accumulation of NMu within different parts of the plant body were proved by elemental analysis of dried plant samples.


Assuntos
Silicatos de Alumínio/toxicidade , Fabaceae/efeitos dos fármacos , Nanopartículas/toxicidade , Poluentes do Solo/toxicidade , Silicatos de Alumínio/química , Silicatos de Alumínio/metabolismo , Fabaceae/crescimento & desenvolvimento , Nanopartículas/química , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Espectrometria por Raios X
8.
BMC Struct Biol ; 10: 6, 2010 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-20170556

RESUMO

BACKGROUND: Catalytic activity of influenza neuraminidase (NA) facilitates elution of progeny virions from infected cells and prevents their self-aggregation mediated by the catalytic site located in the body region. Research on the active site of the molecule has led to development of effective inhibitors like oseltamivir, zanamivir etc, but the high rate of mutation and interspecies reassortment in viral sequences and the recent reports of oseltamivir resistant strains underlines the importance of determining additional target sites for developing future antiviral compounds. In a recent computational study of 173 H5N1 NA gene sequences we had identified a 50-base highly conserved region in 3'-terminal end of the NA gene. RESULTS: We extend the graphical and numerical analyses to a larger number of H5N1 NA sequences (514) and H1N1 swine flu sequences (425) accessed from GenBank. We use a 2D graphical representation model for the gene sequences and a Graphical Sliding Window Method (GSWM) for protein sequences scanning the sequences as a block of 16 amino acids at a time. Using a protein sequence descriptor defined in our model, the protein sliding scan method allowed us to compare the different strains for block level variability, which showed significant statistical correlation to average solvent accessibility of the residue blocks; single amino acid position variability results in no correlation, indicating the impact of stretch variability in chemical environment. Close to the C-terminal end the GSWM showed less descriptor-variability with increased average solvent accessibility (ASA) that is also supported by conserved predicted secondary structure of 3' terminal RNA and visual evidence from 3D crystallographic structure. CONCLUSION: The identified terminal segment, strongly conserved in both RNA and protein sequences, is especially significant as it is surface exposed and structural chemistry reveals the probable role of this stretch in tetrameric stabilization. It could also participate in other biological processes associated with conserved surface residues. A RNA double hairpin secondary structure found in this segment in a majority of the H5N1 strains also supports this observation. In this paper we propose this conserved region as a probable site for designing inhibitors for broad-spectrum pandemic control of flu viruses with similar NA structure.


Assuntos
Vírus da Influenza A Subtipo H1N1/enzimologia , Virus da Influenza A Subtipo H5N1/enzimologia , Neuraminidase/química , Proteínas Virais/química , Sequência de Aminoácidos , Animais , Aves , Dados de Sequência Molecular , Estrutura Terciária de Proteína , RNA/química , Suínos
9.
J Chem Inf Model ; 49(11): 2627-38, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19778054

RESUMO

Study of mutational changes in neuraminidase (NA) gene sequences is important to track the effectiveness of the inhibitors to the H5N1 avian flu virus that targets this component of the viral apparatus. Our analysis based on numerical characterization studies of 682 complete neuraminidase gene and protein sequences available in the database, updated to March 2009, and which extends our previous work based on a sample of 173 sequences has revealed several interesting features. We have noticed that identical sequences have appeared over significant distances in space and time, raising the need for a deeper understanding of the longevity of such viral strains in the environment. Structural sections like transmembrane, stalk, body, and C-terminal tail regions have shown independent recombinations between strains from various species including human and avian hosts highlighting influenza's flexibility in host selection and recombination. Our analysis confirmed a biased nature in mutational accumulation in structural segments: a highly conserved 50-base C-terminal tail section identified in our earlier paper seems to accumulate mutational changes at a rate of about a fifth to an eighth of transmembrane and stalk regions, although the length is about half of these. Parallel study of the equivalent section to the C-terminal region in protein sequences reveals only 13 separate varieties, and all the other 669 sequences are duplicates to three of these varieties showing the highly conserved nature of this segment. Our analysis of active site related bases and amino acids showed highly conserved characteristic of those constructs, whereas the rest of the segments demonstrated rather large mutational changes. These kinds of high level of mutation in major part of the H5N1 NA sequences and recombinations within structural segments coupled with strong conservation of a few select segments show that the potential of rapid mutations to more virulent forms of this variety of avian flu continue to remain of concern, especially with the possibility of long duration dormancy of some of these viral strains, whereas islands of highly conserved segments could signify potential regions for inhibitor designs.


Assuntos
Virus da Influenza A Subtipo H5N1/enzimologia , Mutação , Neuraminidase/genética , Recombinação Genética
10.
Eur J Pharm Sci ; 135: 91-102, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078644

RESUMO

Montmorillonite Clay (MMT) is aimed to develop as an orally administrable drug delivery vehicle with enhanced efficacy. Aiming to enhance the therapeutic index of methotrexate, curcumin is concomitantly used with methotrexate in the present study. Being folate antagonist in nature, methotrexate is internalized into cells by folate receptor (FR); which is over-expressed in certain human cancer cells such as cervical carcinoma cells (HeLa). Firstly, montmorillonite Clay (MMT) is organically modified (OMMT) with cetyl trimethyl ammonium bromide (CTAB) and used to intercalate curcumin and methotrexate separately, designated as OMMT-Cur and OMMT-MTX, respectively. XRD pattern demonstrated successful intercalation of therapeutics and an increase in clay interlayer distance facilitated by CTAB. The dissolution kinetics of methotrexate follows Higuchi model for both Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF), while the release kinetics for curcumin fitted into Higuchi model for SGF and Hixson-Crowell model for SIF, respectively. OMMT-MTX are able to discriminate FR-positive HeLa cells from FR-negative breast cancer cells (MCF7); irrespective of alike cellular phenotypes. Further, the pre-treatment of HeLa cells with curcumin improves its sensitivity towards methotrexate causing a greater killing of the Hela cells. Together, the results propose the concomitant use of curcumin and methotrexate for successfully targeting highly invasive FR-positive carcinomas by means of folate receptor using MMTs.


Assuntos
Antineoplásicos/administração & dosagem , Bentonita/química , Argila/química , Curcumina/farmacologia , Portadores de Fármacos/química , Antagonistas do Ácido Fólico/administração & dosagem , Metotrexato/administração & dosagem , Antineoplásicos/química , Sobrevivência Celular/efeitos dos fármacos , Cetrimônio/química , Liberação Controlada de Fármacos , Receptor 2 de Folato/metabolismo , Antagonistas do Ácido Fólico/química , Células HeLa , Humanos , Células MCF-7 , Metotrexato/química
11.
Comput Biol Chem ; 68: 143-152, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28342423

RESUMO

The Zika virus infections have reached epidemic proportions in the Latin American countries causing severe birth defects and neurological disorders. While several organizations have begun research into design of prophylactic vaccines and therapeutic drugs, computer assisted methods with adequate data resources can be expected to assist in these measures to reduce lead times through bioinformatics approaches. Using 60 sequences of the Zika virus envelope protein available in the GenBank database, our analysis with numerical characterization techniques and several web based bioinformatics servers identified four peptide stretches on the Zika virus envelope protein that are well conserved and surface exposed and are predicted to have reasonable epitope binding efficiency. These peptides can be expected to form the basis for a nascent peptide vaccine which, enhanced by incorporation of suitable adjuvants, can elicit immune response against the Zika virus infections.


Assuntos
Biologia Computacional , Desenho de Fármacos , Peptídeos/imunologia , Vacinas Virais/imunologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Adjuvantes Imunológicos , Epitopos/química , Epitopos/imunologia , Peptídeos/síntese química , Peptídeos/química , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vacinas Virais/síntese química , Vacinas Virais/química , Zika virus/química , Zika virus/genética , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/virologia
13.
Int J Bioinform Res Appl ; 11(6): 469-82, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26642358

RESUMO

Dengue viral attacks have been reported in various parts of India in recent years. In this paper we report on our studies of the characterisation and evolutionary aspects of gene sequences of the envelope glycoprotein of the prevalent Indian dengue virus type 1. Comparison with sequences from other countries shows that the envelope genes identified in India are closely related to strains from Malaysia. From the evolutionary point of view the envelope gene sequences of this dengue virus of India for past few years show that a marked mutational shift in the nucleotide sequences of the envelope gene have taken place from around the year 2000. Also, phylogenetic relationship with other three sera of dengue virus reported in India from 2005 shows that the dengue virus 1 is more closely related to dengue viruses 3 and 4 and relatively distantly to dengue virus 2.

14.
Comput Biol Chem ; 59 Pt A: 8-15, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26364271

RESUMO

The sudden emergence of a human infecting strain of H7N9 influenza virus in China in 2013 leading to fatalities in about 30% of the cases has caused wide concern that additional mutations in the strain leading to human to human transmission could lead to a deadly pandemic. It may happen in a short time span as the outbreak of H7N9 is more and more recurrent, which implies that H7N9 evolution is speeding up. H7N9 flu strains were not known to infect humans before this attack in China in February 2013 and it was solely an avian strain. While currently available drugs such as oseltamivir have been found to be largely effective against the H7N9, albeit with recent reported cases of development of resistance to the drug, there is a necessity to identify alternatives to combat this disease, especially if it assumes pandemic proportions. In our work, we have tried to investigate for the genetic changes in hemagglutinin (HA) protein sequence that lead to human infection by an avian infecting virus and identify possible peptide targets to design vaccines to control this upcoming risk. We identified three highly conserved regions in all H7 subtypes, of which one particular immunogenic surface exposed region was found to be well conserved in all human infecting H7N9 strains (accessed up to 27th March 2014). Compared to H7N9 avian strains, we identified two mutations in this conserved region at the receptor binding site of all post-February 2013 human-infecting H7N9China hemagglutinin protein sequences. One of the mutations is very close (3.6 Å) to the hemagglutinin sialic acid binding pocket that may lead to better binding to human host's sialic acid due to the changes in hydrophobicity of the microenvironment of the binding site. We found that the peptide region with these mutational changes that are specific for human infecting H7N9 virus possess the possibility of being used as target for a peptide vaccine.


Assuntos
Simulação por Computador , Hemaglutininas/química , Hemaglutininas/imunologia , Subtipo H7N9 do Vírus da Influenza A/química , Subtipo H7N9 do Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , China , Humanos , Vacinas contra Influenza/química
15.
Comput Biol Chem ; 51: 51-6, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24929545

RESUMO

Rotavirus, the major cause of infantile nonbacterial diarrhea, was found to be associated with development of diabetes-associated auto-antibodies. In our study we tried to find out further potential autoimmune threats of this virus using bioinformatics approach. We took rotaviral proteins to study similarity with Homo sapiens proteome and found most conserved structural protein VP6 matches at two regions with ryanodine receptor, an autoimmune target associated with myasthenia gravis. Myasthenia gravis, a chronic neurodegenerative autoimmune disorder with no typical known reason, is characterized by fluctuating muscle weakness which is typically enhanced during muscular effort. Affected patients generate auto antibodies against mainly acetyl choline receptor and sarcoplasmic reticulum calcium-release channel protein ryanodine receptor. Further, we observed that two regions which matched with ryanodine receptor remain conserved in all circulating rotaviral strains and showed significant antigenecity with respect to myasthenia gravis associated HLA haplotypes. Overall, our study detected rotaviral VP6 as a potential threat for myasthenia gravis and enlighten an area of virus associated autoimmune research.


Assuntos
Antígenos Virais/química , Proteínas do Capsídeo/química , Epitopos/química , Antígenos HLA/química , Rotavirus/química , Canal de Liberação de Cálcio do Receptor de Rianodina/química , Sequência de Aminoácidos , Antígenos Virais/imunologia , Autoimunidade , Sítios de Ligação , Capsídeo/química , Capsídeo/imunologia , Proteínas do Capsídeo/imunologia , Biologia Computacional , Epitopos/imunologia , Antígenos HLA/imunologia , Haplótipos , Humanos , Modelos Moleculares , Mimetismo Molecular , Dados de Sequência Molecular , Miastenia Gravis/complicações , Miastenia Gravis/imunologia , Miastenia Gravis/virologia , Ligação Proteica , Rotavirus/imunologia , Infecções por Rotavirus/complicações , Infecções por Rotavirus/imunologia , Infecções por Rotavirus/virologia , Canal de Liberação de Cálcio do Receptor de Rianodina/imunologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
16.
Curr Comput Aided Drug Des ; 10(4): 285-302, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25794303

RESUMO

Influenza viruses are characterized by two surface proteins - the hemagglutinin (HA) of which there are 16 varieties, and the neuraminidase (NA) of which there are 9, each subtype characterized by its antigenic properties. Although theoretically 16 x 9 combinations are possible, only a few like the H1N1, H3N2, etc are seen to occur more frequently. Numerous studies with select subtypes like H1N1, H5N1, etc., have explained this phenomena by indicating that viral viability necessitates functional balance between the NA and HA so that only some combinations are favored. However, the reasons for this balance or its characteristics and whether this is universal for influenza subtypes are not yet known. Using novel graphical techniques and hypothesizing a coupling between the HA and NA, we devised a coupling factor to estimate the interdependence, if any, between HA and NA sequences covering a global sample of 10 subtypes and 164 sequences. We found that (a) the coupling we hypothesized between HAs and NAs is characteristic of each subtype, (b) within each subtype the coupling value is significantly different for human infecting strains and those that infect avians, and (c) artificial strains made up by mixing and matching HAs and NAs from different subtypes produce coupling factors that are far from the characteristic values for the parent subtype indicating possibly non-viable viruses, a result that matches with experimental evidence of Zhang et al. [1]. We also show that some natural strains that did not fit the characteristic values for its subtype could have been possible mismatches during viral packaging. Our observations have important consequences for drug and vaccine design and for monitoring of influenza virus reassortments and possible evolution of human pandemics.


Assuntos
Simulação por Computador , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Vírus da Influenza A/metabolismo , Neuraminidase/metabolismo , Animais , Desenho de Fármacos , Humanos , Ligação Proteica
17.
Colloids Surf B Biointerfaces ; 108: 358-65, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23584362

RESUMO

Copper nanoparticle based clay composite has been synthesized by in situ reduction of a copper ammonium complex ion and characterized by different analytical instruments. The copper nanoparticles were both intercalated and adsorbed on the surface with diameters of <5nm (for intercalated) and 25-30nm (for adsorbed). The composite showed good stability for over 3 months in air. Excellent antimicrobial activity of the composite was observed on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis with mortality rates >90% after 12h. Cellular membrane damage permeated by direct attachment of the composite and indirect damage caused by released copper ion are the primary sources of antibacterial action. Cytotoxicity measurements showed minimal adverse effect on the two human cell lines beyond the M.B.C. value for the microorganisms studied. In the present form the clay composite shows good promise for use in therapeutic applications.


Assuntos
Antibacterianos/síntese química , Bentonita/química , Cobre/química , Nanopartículas Metálicas/química , Nanopartículas/química , Antibacterianos/farmacologia , Cátions Bivalentes , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Inibição de Contato/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Humanos , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
18.
Mater Sci Eng C Mater Biol Appl ; 32(6): 1358-65, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24364932

RESUMO

The increasing accumulation of fly ash from thermal power plants poses a major problem to the environment. The present work reflects the novel utilization of this profusely available industrial waste in the form of an antibacterial hard ceramic material by treating fly ash with ferric oxide (Fe2O3) and titania (TiO2) during sintering process at 1600 °C. The developed material shows more than 90% bacterial reduction against both Gram-positive and Gram-negative bacteria. The mechanism of their antibacterial action was studied by transmission electron microscopy (TEM) image analysis of the bacterial cross-section. The developed ceramic material acquires hardness due to the enhancement of the natural mullite content in the matrix. The mullite content and the crystallinity of mullite have shown their increasing trend with increasing concentration of the metal oxide during sintering process. A maximum of ~37% increase in mullite was obtained for 7% w/w Fe2O3 and TiO2. Metal oxide lowered the activation energy of the reaction and enhanced the reaction rate of alumina (Al2O3)-silica (SiO2) to form mullite which increases the hardness. The study highlights novel utilization of fly ash as a hard ceramic antibacterial product (bioceramics) for both structural and hygiene applications in an eco-friendly way.


Assuntos
Cerâmica/química , Cinza de Carvão/química , Compostos Férricos/química , Titânio/química , Óxido de Alumínio/química , Óxido de Alumínio/farmacologia , Silicatos de Alumínio/química , Silicatos de Alumínio/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Cerâmica/farmacologia , Cinza de Carvão/farmacologia , Compostos Férricos/farmacologia , Dureza , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Titânio/farmacologia
19.
Mater Sci Eng C Mater Biol Appl ; 32(7): 1897-1905, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34062673

RESUMO

A mullite based antimicrobial ceramic composite has been developed by simple adsorption of copper nano particle suspension. The physico-chemical properties of samples were characterized by different instruments which showed that the composite is well crystalline with homogeneous distribution of copper nanoparticles on the surface. Antimicrobial study was performed by plate count technique which showed >99% mortality for all the bacterial species studied after 24h of incubation. Minimum inhibitory concentration (MIC) values determined by batch culture process showed considerably low values (in terms of copper content) indicating that mullite matrix plays a role in enhancing the antimicrobial efficacy of the composite. Biocompatibility studies on human cancer cell lines indicated that the composite had negligible toxicity below 100µg/mL of Cu content. Thus the composite can be suitable for developing antimicrobial ceramic wares and therapeutic purposes like treatment of variety of microbial infections.

20.
PLoS One ; 7(7): e40749, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22844409

RESUMO

BACKGROUND: Rotaviral diarrhoea kills about half a million children annually in developing countries and accounts for one third of diarrhea related hospitalizations. Drugs and vaccines against the rotavirus are handicapped, as in all viral diseases, by the rapid mutational changes that take place in the DNA and protein sequences rendering most of these ineffective. As of now only two vaccines are licensed and approved by the WHO (World Health Organization), but display reduced efficiencies in the underdeveloped countries where the disease is more prevalent. We approached this issue by trying to identify regions of surface exposed conserved segments on the surface glycoproteins of the virion, which may then be targeted by specific peptide vaccines. We had developed a bioinformatics protocol for these kinds of problems with reference to the influenza neuraminidase protein, which we have refined and expanded to analyze the rotavirus issue. RESULTS: Our analysis of 433 VP7 (Viral Protein 7 from rotavirus) surface protein sequences across 17 subtypes encompassing mammalian hosts using a 20D Graphical Representation and Numerical Characterization method, identified four possible highly conserved peptide segments. Solvent accessibility prediction servers were used to identify that these are predominantly surface situated. These regions analyzed through selected epitope prediction servers for their epitopic properties towards possible T-cell and B-cell activation showed good results as epitopic candidates (only dry lab confirmation). CONCLUSIONS: The main reasons for the development of alternative vaccine strategies for the rotavirus are the failure of current vaccines and high production costs that inhibit their application in developing countries. We expect that it would be possible to use the protein surface exposed regions identified in our study as targets for peptide vaccines and drug designs for stable immunity against divergent strains of the rotavirus. Though this study is fully dependent on computational prediction algorithms, it provides a platform for wet lab experiments.


Assuntos
Antígenos Virais/química , Antígenos Virais/imunologia , Proteínas do Capsídeo/química , Proteínas do Capsídeo/imunologia , Biologia Computacional/métodos , Sequência Conservada , Desenho de Fármacos , Rotavirus/imunologia , Vacinas Virais/imunologia , Animais , Antivirais/farmacologia , Gráficos por Computador , Epitopos/imunologia , Modelos Moleculares , Multimerização Proteica , Estrutura Quaternária de Proteína , Rotavirus/efeitos dos fármacos
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