Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 50
Filtrar
1.
Nano Lett ; 17(5): 2816-2824, 2017 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-28383924

RESUMEN

III-V compound semiconductors are indispensable materials for today's high-end electronic and optoelectronic devices and are being explored for next-generation transistor logic and quantum technologies. III-V surfaces and interfaces play the leading role in determining device performance, and therefore, methods to control their electronic properties have been developed. Typically, surface passivation studies demonstrated how to limit the density of surface states. Strain has been widely used to improve the electronic transport properties and optoelectronic properties of III-Vs, but the potential of this technology to modify the surface properties still remains to be explored. Here we show that uniaxial stress induces a shift in the energy of the surface states of III-V nanowires, modifying their electronic properties. We demonstrate this phenomenon by modulating the conductivity of InAs nanowires over 4 orders of magnitude with axial strain ranging between -2.5% in compression and 2.1% in tension. The band bending at the surface of the nanostructure is modified from accumulation to depletion reversibly and reproducibly. We provide evidence of this physical effect using a combination of electrical transport measurement, Raman spectroscopy, band-structure modeling, and technology computer aided design (TCAD) simulations. With this methodology, the deformation potentials for the surface states are quantified. These results reveal that strain technology can be used to shift surface states away from energy ranges in which device performance is negatively affected and represent a novel route to engineer the electronic properties of III-V devices.

2.
Food Res Int ; 133: 109157, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32466909

RESUMEN

Fish, a highly nutritious, containing a good amount of protein and fatty acids, has TMA and TVB-N present as major factors responsible for quality deterioration during storage and maintaining of fish freshness. Freshness is one of the most important parameters in the fish market. There are many methods of estimating fish freshness, out of which some are very costly while others are not user-friendly. However, with more technological innovations, there have been efforts to make a more reliable method of calculating and analyzing freshness. Parameters chosen for assessing the freshness are sensory, physical, chemical and microbiological including the recent trends such as SDS-PAGE, fast protein liquid chromatography, hyper Spectral Imaging Technique, etc. focused on reducing time, destruction and labor. Traditional and recent methods of evaluation of freshness along with their comparison based on several parameters are needed to link them and making it convenient for upcoming researchers to have a detailed study for having a universal indicator for assessing the freshness of fish. Information in the present article has all the methods of assessing the fish freshness been discussed in detail. There has also been focus on bringing the readers knowledge about the comprehensive information related to recent developments. The recommended limit for different indicators signifies the time period for which the particular fish can be stored and it depends upon several factors like species, surrounding environment and enzymatic and non-enzymatic actions. Based on these demands, this paper is uniquely worked upon to review the different literature which brought all the discussions from the past including the recent innovations in assessing the freshness of different fishes with the help of various indicators as well as a complete study of spoilage and toxicity mechanism leading to deterioration in quality, making it easy for the reader and researchers to have quick glance over the trends and innovations.


Asunto(s)
Peces , Animales
3.
Nat Commun ; 10(1): 5579, 2019 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-31811120

RESUMEN

Although influenza viruses lead to severe illness in high-risk populations, host genetic factors associated with severe disease are largely unknown. As the HLA-A*68:01 allele can be linked to severe pandemic 2009-H1N1 disease, we investigate a potential impairment of HLA-A*68:01-restricted CD8+ T cells to mount robust responses. We elucidate the HLA-A*68:01+CD8+ T cell response directed toward an extended influenza-derived nucleoprotein (NP) peptide and show that only ~35% individuals have immunodominant A68/NP145+CD8+ T cell responses. Dissecting A68/NP145+CD8+ T cells in low vs. medium/high responders reveals that high responding donors have A68/NP145+CD8+ memory T cells with clonally expanded TCRαßs, while low-responders display A68/NP145+CD8+ T cells with predominantly naïve phenotypes and non-expanded TCRαßs. Single-cell index sorting and TCRαß analyses link expansion of A68/NP145+CD8+ T cells to their memory potential. Our study demonstrates the immunodominance potential of influenza-specific CD8+ T cells presented by a risk HLA-A*68:01 molecule and advocates for priming CD8+ T cell compartments in HLA-A*68:01-expressing individuals for establishment of pre-existing protective memory T cell pools.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Antígenos HLA-A/inmunología , Antígenos HLA-A/metabolismo , Virus de la Influenza A/inmunología , Gripe Humana/inmunología , Presentación de Antígeno , Antígenos Virales/química , Línea Celular , Protección Cruzada , Reacciones Cruzadas/inmunología , Epítopos de Linfocito T/inmunología , Antígenos HLA-A/química , Antígenos HLA-A/genética , Humanos , Memoria Inmunológica/inmunología , Subtipo H1N1 del Virus de la Influenza A/inmunología , Modelos Moleculares , Nucleoproteínas/química , Orthomyxoviridae/genética , Orthomyxoviridae/inmunología , Fragmentos de Péptidos/química , Fenotipo , Conformación Proteica , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Proteínas del Núcleo Viral/genética
4.
Acta Biomater ; 3(3): 341-50, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17234464

RESUMEN

Novel microcidal silver films for burn dressings have been produced by magnetron sputtering. The nanostructure and dissolution characteristics of these films exhibiting antimicrobial behavior were studied as a function of the process conditions, namely, gas composition, gas pressure and input power, using transmission electron microscopy (TEM), high-resolution scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and resistivity. TEM revealed that bioactive films were nanocrystalline, with a grain size of the order of 15nm and the presence of twins. Surface morphology studies before and after dissolution suggested that bioactive films released silver at therapeutic levels in the form of nanoparticles or grains. Chemical species identification with XPS showed that the biologically active films were metallic in nature. The importance of oxygen in the sputtering environment, the resultant nanostructure and presence of twins are discussed to explain the unique antimicrobial properties of these silver films.


Asunto(s)
Antiinfecciosos/química , Magnetismo , Nanoestructuras/química , Nanoestructuras/ultraestructura , Plata/química , Materiales Biocompatibles Revestidos/química , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Nanotecnología/métodos , Pseudomonas aeruginosa/efectos de los fármacos , Solubilidad , Análisis Espectral/métodos , Staphylococcus aureus/efectos de los fármacos , Propiedades de Superficie , Volatilización , Agua/química
5.
Hum Gene Ther ; 9(18): 2735-43, 1998 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-9874272

RESUMEN

Herpes simples virus thymidine kinase (HSV-TK) expression plasmid DNA was injected into the joint space of rabbits with antigen-induced arthritis (AIA). Purified plasmid DNA was able to mediate transfection of synovial lining cells and transient overexpression of HSV-TK in the context of active synovial inflammation. The pharmacodynamic distribution of intraarticular expression plasmid DNA was confined to the joint space. Arthritic rabbits treated with intraarticular expression plasmid DNA followed by intravenous ganciclovir (GCV, 5 mg/kg) twice daily for 3 days showed histologic evidence of synovial lining layer cytolysis when articular tissues were examined 21 days posttreatment. There was also a reduction in joint swelling in the TK-treated knees. No untoward clinical effects were observed in the rabbits and no evidence of cytolytic damage specific to the TK-GCV gene therapy was observed either in the articular cartilage or bone. The application of TK-GCV intraarticular gene therapy using purified expression plasmid DNA for the induction of synovial cytolysis may be applicable to the treatment of human inflammatory arthritis.


Asunto(s)
Artritis Experimental/terapia , Terapia Genética , Simplexvirus/genética , Membrana Sinovial/metabolismo , Membrana Sinovial/fisiología , Timidina Quinasa/genética , Animales , Antígenos/administración & dosificación , Antígenos/inmunología , Antivirales/uso terapéutico , Ganciclovir/uso terapéutico , Técnicas de Transferencia de Gen , Articulación de la Rodilla/inmunología , Articulación de la Rodilla/patología , Ovalbúmina/administración & dosificación , Ovalbúmina/inmunología , Plásmidos/administración & dosificación , Plásmidos/genética , Reacción en Cadena de la Polimerasa/métodos , Conejos , Simplexvirus/enzimología , Membrana Sinovial/citología , Timidina Quinasa/metabolismo , Transfección/métodos
6.
Aliment Pharmacol Ther ; 9(5): 575-9, 1995 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8580281

RESUMEN

AIM: To study the effect of non-steroidal anti-inflammatory drugs (NSAIDs) on gastric cell turnover using an in vitro immunohistochemical method of bromodeoxyuridine (BrDU) uptake. METHODS: Thirty patients undergoing routine upper gastrointestinal endoscopy were studied. Sixteen had taken NSAIDs daily for more than 3 months and there were 14 age-matched controls. Endoscopic gastric antral biopsies were obtained and stained immediately using the BrDU technique. Cell proliferation was expressed as a labelling index percentage (LI%) defined as the number of BrDU-labelled nuclei in 10 gastric glands, expressed as a percentage of the total cells in the gastric gland. RESULTS: Gastric infection with Helicobacter pylori was excluded in all patients. Of the 16 patients on NSAIDs, four had gastritis, four had erosions or ulceration and eight had a normal examination. Endoscopy was normal in all patients in the control group. The LI% (mean +/- S.E.M.) in the entire NSAID group was 4.09 +/- 0.29 and in the control group 3.57 +/- 0.29. No significant difference was observed. In the NSAID patients with gastritis and erosions or ulceration, the LI% was 4.99 +/- 0.61 and 3.07 +/- 0.32, respectively. There was no significant difference in LI% between the endoscopic subgroups of patients on NSAIDs or between patients on NSAIDs who had normal endoscopy and the control patients. CONCLUSION: These results provide evidence that refutes the hypothesis that the prevalence of NSAID gastropathy is due to an effect on gastric cell turnover.


Asunto(s)
Antiinflamatorios no Esteroideos/efectos adversos , Mucosa Gástrica/efectos de los fármacos , Antro Pilórico/efectos de los fármacos , Administración Oral , Antiinflamatorios no Esteroideos/administración & dosificación , Bromodesoxiuridina/metabolismo , División Celular/efectos de los fármacos , Diclofenaco/efectos adversos , Mucosa Gástrica/citología , Gastroscopía , Humanos , Ibuprofeno/efectos adversos , Inmunohistoquímica/métodos , Indometacina/efectos adversos , Ácido Mefenámico/administración & dosificación , Ácido Mefenámico/efectos adversos , Naproxeno/efectos adversos , Antro Pilórico/citología
7.
Clin Exp Rheumatol ; 12(4): 423-4, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7955608

RESUMEN

Thrombosis of the inferior vena cava (IVC) is a rare complication of the antiphospholipid syndrome (APS). We report a case of IVC thrombosis in a 27 year-old female who was anticoagulated at the time and who had a history of recurrent deep venous thromboses (DVT), thrombocytopenia and antiphospholipid antibodies (aPL).


Asunto(s)
Síndrome Antifosfolípido/complicaciones , Trombosis/etiología , Vena Cava Inferior , Adulto , Femenino , Humanos , Trombosis/diagnóstico , Tomografía Computarizada por Rayos X
8.
Clin Exp Rheumatol ; 15(5): 507-13, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9307858

RESUMEN

OBJECTIVE: To assess the nature of pleuropulmonary abnormalities, with particular reference to interstitial lung disease (ILD), in patients with systemic lupus erythematosus (SLE). METHODS: 29 patients were prospectively evaluated using high resolution computed tomography (HRCT), plain chest radiography (CXR) and pulmonary function tests (PFTs). Clinical assessments, drug therapy, disease activity, smoking status and serologic markers were also noted. RESULTS: The HRCT was abnormal in 72% (20/29) of patients, while 34% (10/29) had an abnormal CXR. The most frequently detected primary HRCT abnormality was suggestive of ILD and was noted in 11 patients (38%) In 9 of these, ILD was clinically unsuspected, including one patient who had an HRCT suggestive of active alveolitis. Pleuropericardial abnormalities were seen on HRCT in 5 patients (17%). Of 15 patients who were asymptomatic, and had a normal examination, normal CXR and normal PFTs, four (26%) had HRCT features of ILD. There was no correlation between the HRCT appearances and symptoms, disease duration, ds-DNA titres, smoking history or non-pulmonary involvement. Although no statistical significance was noted between abnormal pulmonary function tests and ILD on HRCT (0.10 < p < 0.20), a trend towards significance was noted between disease activity and ILD (0.05 < p < 0.01). CONCLUSION: HRCT is more sensitive than PFTs or CXR in the evaluation of pleuropulmonary disease in SLE. We report an unusually high prevalence of HRCT appearances suggestive of ILD in patients with SLE. Subclinical lung disease is common in patients with SLE.


Asunto(s)
Enfermedades Pulmonares Intersticiales/complicaciones , Lupus Eritematoso Sistémico/complicaciones , Enfermedades Pleurales/complicaciones , ARN Citoplasmático Pequeño , Adulto , Anticuerpos Antinucleares/sangre , Autoantígenos/inmunología , Femenino , Humanos , Enfermedades Pulmonares Intersticiales/diagnóstico por imagen , Enfermedades Pulmonares Intersticiales/inmunología , Lupus Eritematoso Sistémico/inmunología , Masculino , Persona de Mediana Edad , Enfermedades Pleurales/diagnóstico por imagen , Enfermedades Pleurales/inmunología , Pruebas de Función Respiratoria , Ribonucleoproteínas/inmunología , Tomografía Computarizada por Rayos X , Antígeno SS-B
9.
J Plant Physiol ; 160(5): 557-64, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12806785

RESUMEN

Triploid plants of neem were obtained by immature endosperm culture. Immature seeds, at the early dicotyledonous stage of embryo development, is the best explant to raise endosperm callus on MS + NAA (5 mumol/L) + BAP (2 mumol/L) + CH (500 mg L-1). Maximum shoot bud differentiation from the endosperm callus occurred on MS + 5 mumol/L BAP. Shoots were multiplied by forced axillary branching and rooted in vitro. The plants were established in soil. Over 66% of the plants were triploid with chromosome number 2n = 3x = 36. A characteristic feature of the shoots of endosperm origin is the presence of a large number of multi-cellular glands.


Asunto(s)
Azadirachta/crecimiento & desarrollo , Azadirachta/genética , Técnicas de Cultivo/métodos , Poliploidía , Azadirachta/citología , Raíces de Plantas/citología , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Brotes de la Planta/citología , Brotes de la Planta/genética , Brotes de la Planta/crecimiento & desarrollo
10.
Clin Rheumatol ; 14(2): 224-6, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7789067

RESUMEN

The cauda equina syndrome (CES) is an infrequently recognised and poorly understood complication of ankylosing spondylitis (AS). We report a case of CES with enlarged caudal sac and multiple posterior arachnoid diverticula eroding the laminae and spinous processes of the lumbosacral vertebrae in a patient with long-standing AS. The diagnosis was established using computerised tomography (CT) and magnetic resonance imaging (MRI).


Asunto(s)
Cauda Equina , Síndromes de Compresión Nerviosa/etiología , Espondilitis Anquilosante/complicaciones , Cauda Equina/diagnóstico por imagen , Cauda Equina/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Síndromes de Compresión Nerviosa/diagnóstico , Síndromes de Compresión Nerviosa/fisiopatología , Espondilitis Anquilosante/diagnóstico , Espondilitis Anquilosante/fisiopatología , Tomografía Computarizada por Rayos X
11.
Clin Rheumatol ; 14(4): 445-50, 1995 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-7586983

RESUMEN

We describe four patients with rheumatoid arthritis and unilateral upper limb oedema. In all cases, qualitative lymphoscintigraphy showed lymphatic obstruction in the affected limb.


Asunto(s)
Artritis Reumatoide/complicaciones , Linfedema/etiología , Adulto , Anciano , Brazo , Artritis Reumatoide/diagnóstico por imagen , Femenino , Humanos , Linfedema/diagnóstico por imagen , Linfografía , Persona de Mediana Edad , Cintigrafía
12.
J Biosci Bioeng ; 93(2): 215-20, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-16233190

RESUMEN

Submerged cultivation of Podophyllum hexandrum for the production of podophyllotoxin was carried out in a 3l stirred tank bioreactor fitted with a low-shear Setric impeller. The specific requirements of the medium, such as carbon source (sugar) and light, were established for the growth of and podophyllotoxin production by P. hexandrum in suspension cultures. Substitution of sucrose by glucose resulted in higher growth and podophyllotoxin production. The biosynthesis of podophyllotoxin was favored when plant cells were cultivated in the dark. An agitation speed of 100 rpm was sufficient to mix the culture broth in the bioreactor without causing any significant cell damage. Biomass and podophyllotoxin accumulation in 3 l bioreactor under batch growth conditions were 6.5 g/l and 4.26 mg/l, respectively, in 22 d. This resulted in an overall podophyllotoxin productivity of 0.19 mg/(l.d), which represented an increase of 27% in comparison to its productivity in a shake flask. Podophyllotoxin production was found to be a combined growth-associated and non-growth associated process.

13.
J Econ Entomol ; 96(6): 1935-41, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14977136

RESUMEN

Antibiosis-based resistance to two insect pests of rice, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) and Marasmia patnalis Bradley (Lepidoptera: Pyralidae), was compared in 11 F1 hybrids and their parental lines. Our objective was to determine whether hybrids show heterosis (hybrid vigor) for insect resistance or susceptibility. Heterosis is defined as the amount by which a hybrid exceeds its midparent value or its better parent. Overall, we did not find evidence of heterosis or heterobeltiosis (a type of heterosis in which a hybrid exceeds its better parent) for antibiosis-based resistance or susceptibility to either of the insects. One hybrid, IR64616H, seemed more resistant to M. patnalis than its better parent but none of the other hybrids showed heterobeltiosis for resistance or susceptibility to either insect. Three hybrids had resistance to N. lugens that exceeded their midparent value, possibly due to dominant resistance in one of the parents. The increased frequency and severity of insect outbreaks on hybrid rice that have been reported in China may be attributable to factors other than diminished antibiosis in hybrids, such as greater attractiveness of hybrids to migrating or dispersing insects or differences in agronomic practices applied to hybrids and inbred rice cultivars.


Asunto(s)
Hemípteros/fisiología , Vigor Híbrido , Hibridación Genética , Lepidópteros/fisiología , Oryza/genética , Animales , Enfermedades de las Plantas/genética
14.
Funct Neurol ; 13(3): 253-6, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9800153

RESUMEN

In this paper we review some theories about the process of senescence and death, in particular the theory of accumulation of mutations and the theory of antagonistic pleiotropism. These theories are reviewed in the light of existing scientific evidence, with particular reference to that which points to the possible role of interactions between genes and environment. We conclude that mortality studies, particularly on migrant populations may be an important tool for clarifying this major issue.


Asunto(s)
Envejecimiento/genética , Predisposición Genética a la Enfermedad/mortalidad , Distribución por Edad , Animales , Argentina/epidemiología , Trastornos Cerebrovasculares/genética , Trastornos Cerebrovasculares/mortalidad , Ambiente , Humanos , Italia/epidemiología , Italia/etnología , Modelos Teóricos , Distribución por Sexo , Migrantes/estadística & datos numéricos
15.
Ir J Med Sci ; 162(11): 450-1, 1993 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8113032

RESUMEN

We performed percutaneous endoscopic gastrostomy (PEG) in 30 patients with prolonged swallowing difficulty (> 4 weeks duration). The average procedure time was 25 minutes. PEG insertion was done on an outpatient basis in four patients. The complication rate was 10% and included failed insertion, peristomal infection and herniation of the gastric mucosa at the gastrostomy exist site. At follow-up, the PEG tube continued to function in 18/22 of the surviving patients with a median in-use time of 85 days. Seven patients died from their original disease. Over a 28-day period, the weight gain among the patients ranged from 3kg to 7kg (mean 4.5kg) and average serum albumin increased from 29g/dl to 35g/dl. This confirms that PEG is a safe, easy and effective method of long-term enteral feeding in patients with neurological disease.


Asunto(s)
Trastornos de Deglución/terapia , Nutrición Enteral , Gastroscopía , Gastrostomía/métodos , Adulto , Anciano , Anciano de 80 o más Años , Trastornos de Deglución/etiología , Trastornos de Deglución/mortalidad , Estudios de Seguimiento , Gastroscopía/métodos , Humanos , Persona de Mediana Edad , Enfermedades del Sistema Nervioso/complicaciones , Tasa de Supervivencia
16.
Ir J Med Sci ; 168(3): 197-200, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10540788

RESUMEN

The prevalence of Rheumatoid Arthritis (RA) in Ireland has never been established. Studies from different countries show varying rates, being almost 100 per cent greater in the highlands of Scotland (10/1,000) than in rural Lesotho (6/1,000). A recent study also suggests a fall in the prevalence of RA among women in the London urban area. Given these variations the validity of extrapolating prevalence rates established for other countries to Ireland is questionable. This study aimed to establish a prevalence rate for RA in a defined Dublin population. A self-administered questionnaire was sent to 2,500 people chosen at random from the electoral register. The questionnaire was designed to select out both undiagnosed patients and those with definite arthritis. Respondents whose replies indicated an arthritic process, but in whom no diagnosis had been made, were asked to attend for further assessment and investigations as appropriate. Those who responded that they had been diagnosed with arthritis were asked for consent to inspect their hospital or general practitioner records. A diagnosis of RA was based on American Rheumatism Association (ARA) criteria. Valid responses were received from 1,227 people surveyed (response rate = 49 per cent). Six cases of RA were identified including 2 previously undiagnosed cases. A prevalence rate of 5/1,000 has been estimated based on these findings.


Asunto(s)
Artritis Reumatoide/epidemiología , Adulto , Femenino , Humanos , Irlanda/epidemiología , Masculino , Persona de Mediana Edad , Prevalencia
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA