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1.
Cryo Letters ; 44(1): 20-25, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36629838

RESUMO

Cryopreservation of pollen grains is an effective means of conserving desired germplasm of crop plants. Cryoconserved pollen are expected to be long-lived and thus can be suitably retrieved to overcome hybridization constraints imposed by a variety of reasons. We ascertained the performance of oil palm pollen grains (Tenera hybrids) that were cryobanked 23 years ago using liquid nitrogen (-196 degree C). Cryostored pollen were assessed for viability, in-vitro germinability and vigour. Our analysis showed a marginal decline in viability, assessed through fluorochromatic reaction test, of cryopreserved pollen as compared to fresh ones (pre-storage assessment); however, the viability did not decline in the cryostate since it was last tested 15 years back. On the other hand, germinability and vigour of cryopreserved pollen were maintained to the levels of fresh pollen. Our study, for the first time, demonstrates the amenability of pollen grains for cryopreservation of any plant species beyond a period of two decades in general, and that for oil palm in particular. doi.org/10.54680/fr23110110512.


Assuntos
Criopreservação , Pólen
3.
Plant Biol (Stuttg) ; 20(3): 546-554, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29330901

RESUMO

Reproductive success of a plant species is largely influenced by the outcome of mating pattern in a population. It is believed that a significantly larger proportion of animal-pollinated plants have evolved a mixed-mating strategy, the extent of which may vary among species. It is thus pertinent to investigate the key contributors to mating success, especially to identify the reproductive constraints in depauperate populations of threatened plant species. We examined the contribution of floral architecture, pollination mechanism and breeding system on the extent of outcrossing rate in a near-threatened tree species, Wrightia tomentosa. The breeding system was ascertained from controlled pollination experiments. In order to determine outcrossing rate, 60 open-pollinated progeny were analysed using an AFLP markers. Although the trees are self-compatible, herkogamy and compartmentalisation of pollen and nectar in different chambers of the floral tube effectively prevent spontaneous autogamy. Pollination is achieved through specialised interaction with moths. Differential foraging behaviour of settling moths and hawkmoths leads to different proportions of geitonogamous and xenogamous pollen on the stigma. However, most open-pollinated progeny were the result of xenogamy (outcrossing rate, tm = 0.68). The study shows that floral contrivances and pollination system have a strong influence on mating pattern. The differential foraging behaviour of the pollinators causes deposition of a mixture of self- and cross-pollen to produce a mixed brood. Inbreeding depression and geitonogamy appear to play a significant role in sustaining mixed mating in this species.


Assuntos
Apocynaceae/fisiologia , Flores/fisiologia , Polinização/fisiologia , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Apocynaceae/anatomia & histologia , Apocynaceae/genética , Ecologia , Flores/anatomia & histologia , Hibridização Genética/fisiologia , Reprodução/fisiologia , Árvores/anatomia & histologia , Árvores/fisiologia
4.
Toxicol In Vitro ; 30(1 Pt B): 561-8, 2015 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-26362509

RESUMO

We have recently developed two hemi-cornea models (Bartok et al., Toxicol in Vitro 29, 72, 2015; Zorn-Kruppa et al. PLoS One 9, e114181, 2014), which allow the correct prediction of eye irritation potential of chemicals according to the United Nations globally harmonized system of classification and labeling of chemicals (UN GHS). Both models comprise a multilayered epithelium and a stroma with embedded keratocytes in a collagenous matrix. These two models were compared, using a set of fourteen test chemicals. Their effects after 10 and 60 minutes (min) exposure were assessed from the quantification of cell viability using the MTT reduction assay. The first approach separately quantifies the damage inflicted to the epithelium and the stroma. The second approach quantifies the depth of injury by recording cell death as a function of depth. The classification obtained by the two models was compared to the Draize rabbit eye test and an ex vivo model using rabbit cornea (Jester et al. Toxicol in Vitro. 24, 597-604, 2010). With a 60 min exposure, both of our models are able to clearly differentiate UN GHS Category 1 and UN GHS Category 2 test chemicals.


Assuntos
Córnea/efeitos dos fármacos , Irritantes/toxicidade , Testes de Toxicidade/métodos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Córnea/patologia , Humanos , Modelos Biológicos
5.
Eye (Lond) ; 29(6): 808-14, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25857609

RESUMO

PURPOSE: To evaluate changes in ocular surface and central corneal sub-basal nerve fiber layer (SBNFL) after topical cyclosporin therapy in chronic glaucoma patients on long-term topical antiglaucoma therapy. METHODS: A prospective comparative study of ocular surface evaluation of chronic glaucoma patients on long-term topical therapy treated concurrently with a topical cyclosporine 0.05% twice daily for 6 months and controls was done. The study parameters evaluated at recruitment and at the 6-month follow-up included details of topical antiglaucoma medications, visual acuity, intraocular pressure, ocular surface evaluation parameters (TBUT, Schirmers I, ocular surface staining scores and ocular surface disease (OSD) index score (OSDI)), central corneal sensation (Cochet Bonnett aesthesiometer), and central confocal microscopy to study the SBNFL density (SBNFLD). RESULTS: Thirty-two eyes of 16 patients with chronic glaucoma and 30 eyes of 15 normal subjects as controls were studied. Mean TBUT, pre/post CsA treatment was 8.67±3.01/12.24±1.83 s (P=0.007). Mean conjunctival/corneal staining scores pre/post CsA treatment were 3.38±1.93/1.50±0.718 (P=0.00) /5.19±1.82/1.81±0.78 (P=0.098), respectively. Mean OSDI pre/post CsA treatment scores were 30.63±14.61/14.76±6.06 (P=0.007). Mean corneal sensations scores pre/post CsA treatment were 4.64±0.46/4.94±0.39 (P=0.002). Central corneal SBNFLD pre and post CsA treatment was 8811.35±2985.29/10335.13±4092.064 µm/mm(2) (P=0.0001). CONCLUSIONS: Schirmer's test, ocular surface staining scores, OSDI, corneal sensations, and corneal SBNFLD showed a statistically significant improvement following a 6-month concurrent topical CsA therapy.


Assuntos
Anti-Hipertensivos/uso terapêutico , Córnea/inervação , Ciclosporina/uso terapêutico , Glaucoma/tratamento farmacológico , Imunossupressores/uso terapêutico , Doenças do Nervo Trigêmeo/tratamento farmacológico , Administração Tópica , Adulto , Idoso , Doença Crônica , Combinação de Medicamentos , Feminino , Glaucoma/fisiopatologia , Humanos , Pressão Intraocular/efeitos dos fármacos , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Fibras Nervosas/efeitos dos fármacos , Fibras Nervosas/fisiologia , Soluções Oftálmicas , Estudos Prospectivos , Nervo Trigêmeo/efeitos dos fármacos , Nervo Trigêmeo/fisiopatologia , Doenças do Nervo Trigêmeo/fisiopatologia , Acuidade Visual/efeitos dos fármacos , Adulto Jovem
7.
Br J Pharmacol ; 171(17): 4038-50, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24837879

RESUMO

BACKGROUND AND PURPOSE: The aim of the present study was to evaluate the immunomodulatory and chemotherapeutic potential of alginate-(SA) coated nanocapsule (NCs) loaded with doxorubicin (SA-NCs-DOX) against visceral leishmaniasis in comparison with nano-emulsions containing doxorubicin (NE-DOX). EXPERIMENTAL APPROACH: NE-DOX was prepared using low-energy emulsification methods. Stepwise addition of protamine sulphate and SA in a layer-by-layer manner was used to form SA-NCs-DOX. SA-NCs-DOX, NE-DOX and Free DOX were compared for their cytotoxicity against Leishmania donovani-infected macrophages in vitro and generation of T-cell responses in infected hamsters in vivo. KEY RESULTS: Size and ζ potential of the NE-DOX and SA-NCs-DOX formulations were 310 ± 2.1 nm and (-)32.6 ± 2.1 mV, 342 ± 4.1 nm and (-)29.3 ± 1.2 mV respectively. SA-NCs-DOX was better (1.5 times) taken up by J774A.1 macrophages compared with NE-DOX. SA-NCs -DOX showed greater efficacy than NE-DOX against intramacrophagic amastigotes. SA-NCs-DOX treatment exhibited enhanced apoptotic efficiency than NE-DOX and free DOX as evident by cell cycle analysis, decrease in mitochondrial membrane potential, ROS and NO production. T-cell responses, when assessed through lymphoproliferative responses, NO production along with enhanced levels of iNOS, TNF-α, IFN-γ and IL-12 were found to be up-regulated after SA-NCs-DOX, compared with responses to NE-DOX in vivo. Parasitic burden was decreased in Leishmania-infected hamsters treated with SA-NCs-DOX, compared with NE-DOX. CONCLUSIONS AND IMPLICATIONS: Our results provide insights into the development of an alternative approach to improved management of leishmaniasis through a combination of chemotherapy with stimulation of the innate immune system.


Assuntos
Alginatos/farmacologia , Antiprotozoários/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Daunorrubicina/farmacologia , Leishmania donovani/efeitos dos fármacos , Nanocápsulas/química , Células Th1/efeitos dos fármacos , Alginatos/administração & dosagem , Alginatos/química , Animais , Antiprotozoários/administração & dosagem , Antiprotozoários/química , Linhagem Celular , Materiais Revestidos Biocompatíveis/administração & dosagem , Materiais Revestidos Biocompatíveis/química , Cricetinae , Daunorrubicina/administração & dosagem , Daunorrubicina/química , Ácido Glucurônico/administração & dosagem , Ácido Glucurônico/química , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/administração & dosagem , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacologia , Leishmania donovani/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/parasitologia , Masculino , Camundongos , Células Th1/imunologia
8.
Indian J Cancer ; 51(4): 502-5, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-26842177

RESUMO

Oral squamous cell carcinoma (OSCC) is one of the most debilitating cancers in the world and while its causes have been heavily researched, the outcome remains grim. Most of these cancers are identified in the late stage and as a result treatment options are limited. Therefore, researchers have focused their efforts on recognizing and identifying dysplastic tissue that has an increased chance of progressing to cancer. Research has begun to look at cell cycle dysfunctions and in particular, aberrant protein functions as a way of identifying the cellular mechanism at fault. The overexpression of a group of regulatory proteins called cyclins has been demonstrated in many types of dysplasia and carcinomas. Although researchers have identified several different types of cyclins as potential culprits, we chose to focus our study primarily on the overexpression of cyclin A. While most research on oral dysplasia and OSCC has been focused on cyclin D, studies have been done on cyclin A. While the etiology of oral dysplasia/SCC appears to be multifactorial, we chose to compare our results with those of similar studies performed across the globe. The social factors, such as the increased use of tobacco that may have contributed to our results, were compared with similar studies performed in Europe and Asia. While our results were remarkably similar and demonstrated a link between the overexpression of cyclin A in oral dysplasia, there exists some differences and thus may require a multicenter, longitudinal study.


Assuntos
Carcinoma de Células Escamosas/química , Ciclina A/análise , Mucosa Bucal/química , Mucosa Bucal/patologia , Neoplasias Bucais/química , Humanos
9.
Schizophr Res ; 148(1-3): 1-2, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23849885
10.
Ophthalmic Res ; 50(1): 59-64, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23751337

RESUMO

OBJECTIVE: To report the clinical outcome of autologous cultured limbal epithelial cell transplantation (CLECT) followed by deep anterior lamellar keratoplasty (DALK) in paediatric eyes and to correlate the clinical outcome with the phenotype of rejuvenated corneal epithelium. METHODS: Four patients with total limbal stem cell deficiency (LSCD) underwent autologous CLECT. Cultivated cell sheets were transplanted onto the damaged ocular surface followed by DALK surgery. Excised corneal buttons were subjected to histopathological analysis. Data recorded included age, sex, laterality, nature of injury, follow-up period, severity of stem cell deficiency, visual acuity, Schirmer's test and impression cytology. RESULTS: At a mean follow-up period of 19.5 ± 7.4 (range 9-26) months after CLECT, all 4 eyes showed epithelialized and clinically stabilized ocular surface. Manual DALK was performed in all 4 eyes, with a mean follow-up of 9.75 ± 4.5 (range 5-15) months. All eyes exhibited smooth and clear corneal epithelium with improved visual acuity. Excised corneal buttons demonstrated organized corneal epithelial morphology and showed expression of cornea-specific CK3/12 marker. CONCLUSION: Restoration of severely damaged ocular surface following chemical injury by using 2-stage meticulous approaches offers a new modality for the treatment of severe LSCD. Transplantation of cultivated autologous limbal epithelial cell sheet followed by DALK surgery can efficiently restore the corneal phenotype with improved vision.


Assuntos
Queimaduras Químicas/cirurgia , Doenças da Córnea/cirurgia , Transplante de Córnea/métodos , Epitélio Corneano/transplante , Queimaduras Oculares/induzido quimicamente , Limbo da Córnea/cirurgia , Âmnio/transplante , Células Cultivadas , Criança , Feminino , Humanos , Imuno-Histoquímica , Limbo da Córnea/patologia , Masculino , Transplante Autólogo
11.
Indian J Med Res ; 137(4): 643-58, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23703332

RESUMO

Rheumatic fever (RF) and rheumatic heart disease (RHD) continue to be a major health hazard in most developing countries as well as sporadically in developed economies. Despite reservations about the utility, echocardiographic and Doppler (E&D) studies have identified a massive burden of RHD suggesting the inadequacy of the Jones' criteria updated by the American Heart Association in 1992. Subclinical carditis has been recognized by E&D in patients with acute RF without clinical carditis as well as by follow up of RHD patients presenting as isolated chorea or those without clinical evidence of carditis. Over the years, the medical management of RF has not changed. Paediatric and juvenile mitral stenosis (MS), upto the age of 12 and 20 yr respectively, severe enough to require operative treatement was documented. These negate the belief that patients of RHD become symptomatic ≥20 years after RF as well as the fact that congestive cardiac failure in childhood indicates active carditis and RF. Non-surgical balloon mitral valvotomy for MS has been initiated. Mitral and/or aortic valve replacement during active RF in patients not responding to medical treatment has been found to be life saving as well as confirming that congestive heart failure in acute RF is due to an acute haemodynamic overload. Pathogenesis as well as susceptibility to RF continue to be elusive. Prevention of RF morbidity depends on secondary prophylaxis which cannot reduce the burden of diseases. Primary prophylaxis is not feasible in the absence of a suitable vaccine. Attempts to design an antistreptococcal vaccine utilizing the M-protein has not succeeded in the last 40 years. Besides pathogenesis many other questions remain unanswered.


Assuntos
Febre Reumática/epidemiologia , Cardiopatia Reumática/epidemiologia , Ásia/epidemiologia , Doenças das Valvas Cardíacas/complicações , Doenças das Valvas Cardíacas/patologia , Doenças das Valvas Cardíacas/terapia , Humanos , Índia/epidemiologia , Miocardite/complicações , Miocardite/patologia , Miocardite/terapia , Febre Reumática/complicações , Febre Reumática/patologia , Febre Reumática/terapia , Cardiopatia Reumática/complicações , Cardiopatia Reumática/patologia , Cardiopatia Reumática/terapia
12.
Neuroimage ; 81: 484-495, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-21782030

RESUMO

Apathy and depression are heterogeneous syndromes with symptoms that overlap clinically. This clinical overlap leads to problems with classification and diagnosis in clinical populations. No functional imaging study has attempted to separate brain regions altered in apathy from those altered in depression in a clinical population. Parkinson disease (PD) is a disorder in which apathy and depression co-exist in a single population. We evaluate the relationship between apathy, depression, and motor severity of disease in PD, focusing on the relationship between these factors and the amplitude of the low frequency fluctuation (ALFF) in the resting state. We first evaluated if the resting ALFF signal is a reliable measure for our clinical question. For this, we develop and introduce a cross validation approach we term the "Regional Mapping of Reliable Differences" (RMRD) method to evaluate reliability of regions of interest deemed "significant" by standard voxel-wise techniques. Using this approach, we show that the apathy score in this sample is best predicted by ALFF signal in the left supplementary motor cortex, the right orbitofrontal cortex, and the right middle frontal cortex, whereas depression score is best predicted by ALFF signal in the right subgenual cingulate. Disease severity was best predicted by ALFF signal in the right putamen. A number of additional regions are also statistically (but not reliably) correlated with our neuropsychological measures and disease severity. Our results support the use of resting fMRI as a means to evaluate neuropsychiatric states and motor disease progression in Parkinson disease, and the clinical and epidemiologic observation that apathy and depression are distinct pathological entities. Our finding that "significance" and "reliability" are dissociated properties of regions of interest identified as significant using standard voxel-wise techniques suggests that including reliability analyses may add useful scientific information in neurobehavioral research.


Assuntos
Apatia , Mapeamento Encefálico , Depressão/fisiopatologia , Doença de Parkinson/fisiopatologia , Depressão/etiologia , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Doença de Parkinson/complicações , Doença de Parkinson/psicologia
13.
Indian J Plast Surg ; 45(1): 97-101, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22754162

RESUMO

SETTING AND DESIGN: A hospital-based retrospective study of firecracker-related injuries was carried out at a government sponsored hospital in Delhi. MATERIALS AND METHODS: 1373 patients attended the emergency burn care out-patients clinic during 2002-2010 pre-Diwali, Diwali and post-Diwali days. Every year, a disaster management protocol is revoked during these 3 days under the direct supervision of the Ministry of Health and Family Welfare, Government of India. RESULTS: There was an increase in the number of patients of firecracker-related injuries in Delhi national capital region from the year 2002 to 2010, based on the hospital statistics. During the study period, the hospital received approximately one patient with firecracker-related injury per 100,000 population of the city. 73.02% of the victims were 5-30 years old. Majority (90.87%) of them sustained <5% total body surface area burn. CONCLUSIONS: In spite of legislations and court orders, the number of patients is on the rise. The implementation agencies have to analyse the situation to find a way to control this preventable manmade accident. Websites, emails, SMS, social sites, etc. should be used for public education, apart from conventional methods of public awareness.

14.
Epidemiol Psychiatr Sci ; 20(4): 317-27, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22201209

RESUMO

BACKGROUND: Although schizophrenia has been considered a distinct disease entity for the past century, its precise definition and etio-pathophysiology remain obscure and its treatment remains unsatisfactory. In this review, we summarize our state of knowledge about the etiology, pathophysiology, clinical features, and treatment of schizophrenia. METHODOLOGICAL ISSUES: The inadequacy of the major conceptual models of schizophrenia is a major roadblock in providing a coherent explanation for the known facts of this illness, despite these limitations and its changing definitions, the construct of schizophrenia does convey useful information: (i) patients diagnosed as having schizophrenia do have a real disease--they experience both suffering and disability; (ii) a diagnosis of schizophrenia does suggest a distinctive clinical profile--a characteristic long-term course; an admixture of positive, negative, and cognitive symptoms; (iii) a diagnosis of schizophrenia has clear treatment and prognostic implications--likelihood of benefit from antipsychotic treatment and likelihood of incomplete recovery; and (iv) schizophrenia satisfies criteria for a valid diagnostic entity better than almost any other psychiatric diagnosis. DISCUSSION: On the other hand, the concept of schizophrenia has serious shortcomings. First, it is not a single disease entity--it has multiple etiological factors and pathophysiological mechanisms but common phenotypic features. Second, its clinical manifestations are so diverse that its extreme variability has been considered by some to be a core feature. Third, its boundaries remain ill defined and not clearly demarcated from other clinical entities. CONCLUSIONS: A necessary next step is to deconstruct schizophrenia as an entity into component dimensions--endophenotypes linked to unique etiological and pathophysiological processes that may yield unique treatment targets. Innovative approaches are needed to elucidate the biological substrates of these entities because such clarity is vital for replicable research. We conclude by identifying the critical gaps in our knowledge, and unmet needs in our approaches to care, and outline steps that can move the field forward.


Assuntos
Esquizofrenia/diagnóstico , Esquizofrenia/terapia , Animais , Antipsicóticos/uso terapêutico , Humanos , Psicoterapia/métodos , Fatores de Risco , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico
15.
Ultrasonics ; 51(5): 547-53, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21236460

RESUMO

The paper presents an equivalent circuit model of the polymer coated surface acoustic wave (SAW) resonators by combining coupling-of-mode (COM) description of SAW resonators and perturbation calculation of SAW propagation under polymer loading. An expression for the motional load produced by polymer coating is deduced in terms of COM parameters and polymer characteristics. In addition, expressions for the shifts in resonance frequency and attenuation due to polymer loading are obtained. Simulation results are presented for one-port and two-port resonator devices coated with viscoelastic thin polymer film. The influence of polymer film on resonator response is studied with regard to variations in film thickness and shear modulus. The model simplifies understanding of polymer-coated SAW sensors.


Assuntos
Acústica/instrumentação , Desenho Assistido por Computador , Eletrônica/instrumentação , Sistemas Microeletromecânicos/instrumentação , Modelos Teóricos , Polímeros/química , Transdutores , Simulação por Computador , Impedância Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Espalhamento de Radiação
16.
Clin Microbiol Infect ; 16(1): 45-50, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19456832

RESUMO

The diversity and capacity of human rotaviruses for rapid evolution and genetic reassortment suggests that rotavirus vaccine should be designed to provide heterotypic protection. The objective of the present study was to provide information on the circulating genotypes of rotavirus and allied baseline epidemiology in Lucknow, India. In a cross-sectional study, the prevalence of rotavirus G-P types was studied in patients aged 1-36 months with acute watery diarrhoea. Various sociodemographic, environmental and clinical factors were assessed as potential predictors of rotavirus infection; 412 patients with acute watery diarrhoea were recruited into the study from September 2004 to April 2008 and rotavirus was identified in 19.2% (79/412) cases using ELISA and PAGE. The genotypes identified were G1 (38.0%), G2 (15.2%), G3 (16.5%), G9 (10.9%), G4 (5.1%) and mixed G types (10.1%). The most common G-P combinations were G1P[8], G3P[6], G1P[6] and G2P[8]. Rotavirus diarrhoea was found to occur throughout the year with a single peak in winter months (November-January). Rotavirus diarrhoea was found to be associated with children not currently breast fed (adjusted OR 2.2, 95% CI 1.3-3.7, p 0.004), children < or =7 months of age (adjusted OR 1.1, 95% CI 1.0-1.1, p 0.002) and children with severe dehydration (adjusted OR 1.8, 95% CI 1.1-3.0, p 0.03) using multivariate logistic regression. A high degree of strain diversity of rotavirus G and P types was detected. Rotavirus was found to be associated with dehydrating diarrhoea, particularly in children aged 0-7 months, placing them at increased risk of mortality.


Assuntos
Diarreia Infantil/virologia , Infecções por Rotavirus/virologia , Rotavirus/genética , Pré-Escolar , Estudos Transversais , Diarreia Infantil/epidemiologia , Feminino , Genótipo , Humanos , Índia/epidemiologia , Lactente , Modelos Logísticos , Masculino , Análise Multivariada , Prevalência , Fatores de Risco , Rotavirus/classificação , Infecções por Rotavirus/epidemiologia , Estações do Ano
17.
J Nanosci Nanotechnol ; 9(11): 6631-6, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19908576

RESUMO

Single phase nanocrystalline lead zirconate titanate (PZT) powder of composition Pb(Zr(0.52)Ti(0.48))O3 has been prepared by sol-gel process by using lead acetate trihydrate, zirconium propoxide and titanium propoxide as lead, zirconium and titanium precursor materials respectively. XRD, FTIR and TGA/DTA techniques are used to characterize structural, vibrational and thermal changes involved during the formation of PZT nanocrystalline powder with tetragonal phase. XRD pattern exhibits the polycrystalline nature of the powder heat treated at 800 degrees C with preferential orientation of (110) plane. Simultaneous TGA/DTA studies of the gel powder show endothermic and exothermic peaks corresponding to weight loss at different temperatures and increase in weight between 750 degrees C and 800 degrees C which confirms the improvement in crystallization. IR transmittance spectra of the powders heat treated at 650 degrees C and 750 degrees C show the coexistence of rhombohedral and teragonal phases and above this temperature only teragonal phase exists.

18.
Pediatr Neurosurg ; 45(4): 271-5, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19609095

RESUMO

AIMS: It was the aim of this study to report a prospective study of 110 spina bifida patients with hydrocephalus treated by simultaneous ventriculoperitoneal (VP) shunt and repair of the meningomyelocele. METHODS: Between January 2005 and February 2008, 264 patients with spina bifida were admitted to the author's department. Those patients in whom the preoperative cranial ultrasonography measurement of the bifrontal diameter was >26 mm, the bicaudate diameter >20 mm and the diameter of the body of the lateral ventricle >26 mm were predicted to develop postoperative hydrocephalus (n = 245). Of these, 110 patients underwent simultaneous (group 1) VP shunt with repair of the meningomyelocele, while 135 (group 2) underwent sequential surgery due to the preference of the attending consultant. RESULTS: Twenty-two of the 110 patients in group 1 developed complications (wound problems, cerebrospinal fluid leak, shunt malfunction, death) compared with 38 of 135 patients in group 2. The remaining patients had an uneventful postoperative and follow-up course. CONCLUSIONS: Simultaneous VP shunt with surgery for hydrocephalus was feasible in our setup. The rate of complications was not higher than in staged surgery. Single-stage repair of spina bifida with hydrocephalus offers considerable advantage in the form of a reduction in hospital burden, costs and patient morbidity.


Assuntos
Hidrocefalia/diagnóstico por imagem , Hidrocefalia/cirurgia , Cuidados Pré-Operatórios/métodos , Disrafismo Espinal/diagnóstico por imagem , Disrafismo Espinal/cirurgia , Pré-Escolar , Seguimentos , Humanos , Hidrocefalia/complicações , Lactente , Recém-Nascido , Valor Preditivo dos Testes , Crânio/diagnóstico por imagem , Disrafismo Espinal/complicações , Ultrassonografia
19.
Eur Phys J E Soft Matter ; 28(4): 361-8, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19277740

RESUMO

Current-voltage (J-V) characteristics of poly(3-hexylthiophene) (P3HT) are studied at different temperatures upto high voltages approximately 20V in the hole-only device configuration. The characteristics are studied in the temperature range 310-210K. In the intermediate voltage range the J-V characteristics follow J proportional to V(l+1), where l > 1. As the voltage increases to high values J still varies as a power law i.e. as V(m), but contrary to the literature result m becomes < 2. This behavior is explained theoretically in terms of non-zero injection Schottky barriers. The complete analytical expressions for the actual trap filled limit voltage (V'(TFL)) and J-V curves beyond V'(TFL) are presented.

20.
Pediatr Surg Int ; 25(4): 369-72, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19214535

RESUMO

Survival rates for infants who have esophageal atresia (EA) with or without fistula (TEF) have improved dramatically in the past 50 years. Despite excellent long-term survival for patients with esophageal atresia with tracheoesophageal fistula (EA-TEF), many significant complications can occur. Anastomotic leak at the esophagoesophagostomy site is one such problem resulting in considerable morbidity and mortality in these patients. The methods of esophageal anastomosis for long period has remained the simple end to end anastomosis of esophageal ends with various modifications described from time to time. The present study aims to study the effect on the early postoperative complications, following horizontal mattress suture technique on the primary esophageal anastomosis in cases of EA-TEF. A total of 32 patients with EA-TEF, were operated by our technique during a period of 1 year (2007-2008). The results were compared with the patients (n = 66), who were operated by the traditional simple technique during the same period. Among those patients in whom the esophageal anastomosis was done by horizontal mattress suture, only one had major anastomotic leak, while two had minor anastomotic leaks, as compared to six and nine cases correspondingly in other patients in whom anastomosis was done by simple technique. There was single mortality. We propose that, the utilization of our technique of horizontal mattress suture in primary anastomosis of esophagus in cases of EA-TEF significantly reduces the risk of anastomotic leaks and subsequent morbidity and mortality.


Assuntos
Atresia Esofágica/cirurgia , Esôfago/cirurgia , Técnicas de Sutura , Fístula Traqueoesofágica/cirurgia , Anastomose Cirúrgica/métodos , Atresia Esofágica/complicações , Seguimentos , Humanos , Recém-Nascido , Estudos Prospectivos , Fístula Traqueoesofágica/complicações , Resultado do Tratamento
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