Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Med Phys ; 50(7): 4466-4479, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37086040

RESUMO

PURPOSE: A novel compensator-based system has been proposed which delivers intensity-modulated radiation therapy (IMRT) with cobalt-60 beams. This could improve access to advanced radiotherapy in low- and middle-income countries. For this system to be clinically viable and to be adapted into the Radiation Planning Assistant (RPA), being developed to offer automated planning services in low- and middle-income countries, it is necessary to commission and validate it in a commercial treatment planning system (TPS). METHODS: The novel treatment device considered here employs a cobalt-60 source and nine compensators. Each compensator is produced by 3-D printing a thin plastic mold which is then filled on-demand within the machine with reusable 2-mm-diameter spherical tungsten balls. This system was commissioned in the Eclipse TPS and validation tests were conducted with Monte Carlo using Geant4 Application for Tomographic Emission for percentage depth dose, in-plane profiles, penumbra, and IMRT dose validation. And the American Association of Physicists in Medicine Task Group 119 benchmarking testing was performed. Additionally, compensator-based cobalt-60 IMRT plans were created for 46 head-and-neck cancer cases and compared to the linac-based volumetric modulated arc therapy (VMAT) plans used clinically, then dosimetric parameters were evaluated. Beam-on time for each field was calculated. In addition, the measurement was also performed in a limited environment and compared with the Monte Carlo simulations. RESULTS: The differences in percent depth doses and in-plane profiles between the Eclipse and Monte Carlo simulations were 0.65% ± 0.41% and 1.02% ± 0.99%, respectively, and the 80%-20% penumbra agreed within 0.46 ± 0.27 mm. For the Task Group 119 validation plans, all treatment planning goals were met and gamma passing rates were >95% (3%/3 mm criteria). In 46 clinical head-and-neck cases, the cobalt-60 compensator-based IMRT plans had planning target volume (PTV) coverages similar to linac-based VMAT plans: all dosimetric values for PTV were within 1.5%. The organs at risk dose parameters were somewhat higher in cobalt-60 compensator-based IMRT plans versus linac-based VMAT plans. The mean dose differences for the spinal cord, brain, and brainstem were 4.43 ± 1.92, 3.39 ± 4.67, and 2.40 ± 3.71 Gy, while those for the rest of the organs were <1 Gy. The average beam-on time per field was 0.42 ± 0.10 min for the 6 MV multi-leaf-collimator plans while those for the cobalt-60 compensator plans were 0.17 ± 0.01 and 0.31 ± 0.01 min at the dose rates of 350 and 175 cGy/min. There was a good agreement between in-plane profiles from measurements and Monte Carlo simulations, which differences are 1.34 ± 1.90% and 0.13 ± 2.16% for two different fields. CONCLUSIONS: A novel compensator-based IMRT system using cobalt-60 beams was commissioned and validated in a commercial TPS. Plan quality with this system was comparable to that of linac-based plans in all test cases with shorter estimated beam-on times. This system enables reliable, high-quality plans with reduced cost and complexity and may have benefits for underserved regions of the world. This system is being integrated into the RPA, a web-based platform for auto-contouring and auto-planning.


Assuntos
Radioterapia de Intensidade Modulada , Radioterapia de Intensidade Modulada/métodos , Radioisótopos de Cobalto/uso terapêutico , Planejamento da Radioterapia Assistida por Computador/métodos , Dosagem Radioterapêutica
2.
ACS Appl Mater Interfaces ; 14(24): 28310-28320, 2022 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-35687749

RESUMO

Polyimide-Al2O3 membranes are developed as a direct alternative to current polyolefin separators by the electrospinning technique and their chemical structures confirm the carbonyl group with the presence of asymmetric and symmetric stretching and bending vibrations at 1778, 1720, and 720 cm-1 and stretching vibration at 1373 cm-1 for the imide group. Porous nanofiber architecture morphology is realized with a nanofiber thickness of ∼200 nm and shows an ultrasmooth surface and >1 µm pore size in the architecture, built with the chemical constituents of carbon, nitrogen, aluminum, and oxygen elements. The galvanostatic cycling study of the Li/PI-Al2O3/LiFePO4 lithium cell delivers stable charge-discharge capacities of 144/143 mAh g-1 at 0.2 C and 110/100 mAh g-1 at 1 C for 1-100 cycles. The fabricated MCMB/PI-Al2O3/LiFePO4 lithium-ion full-cell reveals less charge transfer resistance of Rct ∼ 25 Ω and yields stable charge-discharge capacities of 125/119 mAh g-1. The thermogravimetric curve for the PI-Al2O3 separator discloses thermal stability up to 525 °C, and the differential scanning calorimetric curve shows a straight line until 300 °C and depicts high thermal stability than the PP separator. In situ multimode calorimetry analysis of the MCMB/PP/LiFePO4 full-cell showed a pronounced exothermic peak at 225 °C with a higher released heat energy of 211 J g-1 at the thermal runaway event, while the MCMB/PI-Al2O3/LiFePO4 full-cell revealed an almost 8-fold less exothermic released heat energy of 25 J g-1 than the Celgard polypropylene separator, which was because the MCMB anode and LiFePO4 cathode can be mechanically isolated without any additional separator's melting and burning reactions, as a fire-suppressant separator for lithium-ion batteries.

3.
Curr Drug Targets ; 23(8): 782-801, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34939539

RESUMO

BACKGROUND: Human papillomavirus (HPV), one of the most frequently transmitted viruses, causes several malignancies, including cervical cancer. AIM: Owing to its unique pathogenicity, the HPV virus can persist in the host organism for a longer duration than other viruses to complete its lifecycle. During its association with the host, HPV causes various pathological conditions affecting the immune system by evading the host's immune mechanisms, thereby leading to the progression of various diseases, including cancer. METHOD: To date, ~ 150 serotypes have been identified, and certain high-risk HPV types are known to be associated with genital warts and cervical cancer. As of now, two prophylactic vaccines are in use for the treatment of HPV infection; however, no effective antiviral drug is available for HPVassociated disease/infections. Numerous clinical and laboratory studies have been conducted to formulate an effective and specific vaccine against HPV infections and associated diseases. RESULT: As the immunological basis of HPV infection and associated disease progress persist indistinctly, deeper insights into immune evasion mechanism and molecular biology of disease would aid in developing an effective vaccine. CONCLUSION: Thus, this systematic review focuses on the immunological aspects of HPV-associated cervical cancer by uncovering immune evasion strategies adapted by HPV.


Assuntos
Alphapapillomavirus , Infecções por Papillomavirus , Neoplasias do Colo do Útero , Feminino , Humanos , Evasão da Resposta Imune , Biologia Molecular , Papillomaviridae , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/prevenção & controle , Neoplasias do Colo do Útero/prevenção & controle
4.
ACS Appl Mater Interfaces ; 14(1): 684-697, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-34964594

RESUMO

Advanced wave-shape non-graphitizable carbon sheets are derived, comprising mesoporous weaved turbostratic micropore enabled stable Na+ ion storage. The non-graphitizable amorphous characteristics are determined from the obtained two broad diffraction peaks at 22.7° and 43.8°. The observed D-band at 1325 cm-1 and G-band at 1586 cm-1 confirm the disordered graphitic structure, attributed to the measured specific surface area of 54 m2 g-1. Mesoporous weaved wave-shape carbon sheet architecture is confirmed by surface morphological studies, showing lattice fringes of disordered graphitic structures and dispersed ring patterns for the non-crystalline characteristics. The predominant stable redox peak at 0.014 V/0.185 V and the broader rectangular shape between 0.9 and 0.15 V depict the adsorption-micropore filling mechanism. The mesoporous hard carbon sheet delivers discharge-charge capacities of 450/311 mAh g-1 (1st cycle) and 263/267 mAh g-1 (250th cycle) at 25 mA g-1, exhibiting a superior anode for sodium-ion batteries. Besides, in situ multimode calorimetry results disclose that the micropore filling Na+ ion storage shows a higher released total heat energy of 721 J g-1 than the adsorption (471 J g-1). Ultimately, differential scanning calorimetry analysis of micropore filling Na+ ion storage (discharged state at 0.01 V) has revealed a predominant exothermic peak at 156 °C with the highest released total heat energy of 2183 J g-1 compared to adsorption (553 J g-1) and deintercalation (85 J g-1), indicating that micropore filling status is more unsafe than the adsorption and deintercalation for SIBs.

5.
Microorganisms ; 9(6)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204446

RESUMO

This study aimed to generate predictive models for growth, sporulation, and ochratoxin A (OTA) production under abiotic climatic variables, including temperatures (15-35 °C) and water activity levels (0.99-0.90 aw) by Aspergillus ochraceus group. The data were divided into three sets: one for training, one for testing, and the third one for model validation. Optimum growth occurred at 0.95 aw and 25 °C and 0.95 aw and 30 °C for A. westerdijkiae and A. steynii, respectively. Significantly improved A. westerdijkiae and A. steynii spore production occurred at 0.95 aw and 20 °C and 0.90 aw and 35 °C, respectively. A. steynii and A. westerdijkiae produced the majority of OTA at 35 °C and 0.95 aw and 25-30 °C at 0.95-0.99 aw, respectively. The accuracy of the third-order polynomial regression model reached 96% in growth cases, 94.7% in sporulation cases, and 90.9% in OTA production cases; the regression coefficients (R2) ranged from 0.8819 to 0.9978 for the Aspergillus ochraceus group. A reliable agreement was reached between the predicted and observed growth, sporulation, and OTA production. The effects of abiotic climatic variables on growth, sporulation, and OTA production of A. ochraceus group have been effectively defined, and the models generated were responsible for adequately predicted and validated models against data from other strains within A. ochraceus group that had been published in the literature under the current treatments. These models could be successfully implemented to predict fungal growth and OTA contamination on food matrices for these strains under these conditions.

6.
ACS Appl Mater Interfaces ; 13(27): 31594-31604, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34185500

RESUMO

A sol-gel process followed by heat treatment derived a layered P2-type NaCoO2 cathode, which depicted unit cell parameters values of a = 2.8389 Å, c = 10.9899 Å, and V = 76.71 Å3 in powder X-ray diffraction pattern. The synthesized cathode exhibited hexagonal, 2D platelets with an ∼300 nm thickness. During the anodic and cathodic sweeps, the cyclic voltammograms revealed multiple redox peaks with the same current densities, shapes, and peak positions, associated with the highly reversible phase transition mechanism of the layered P2-type NaCoO2 cathode. The sodium cells yielded the capacities of 93/92 mAh g-1 at 0.5 C and 87/87 mAh g-1 at 1 C for the 50th charge-discharge cycles. The in situ multimode calorimetry (MMC) studies of sodium cells demonstrated a thermal explosion event, which occurred by sodium melting, short-circuit, electrode decomposition reaction, gas generation, exothermic reaction, released heat energy ,and cell gasket melting. Ultimately, the calculated released total heat energies of ∼550/740 J g-1 for in situ MMC studies and ∼312/594 J g-1 for ex situ DSC analyses (charge state at 4 V and discharge state at 2 V) show that the discharged state of sodiated layered P2-type NaCoO2 cathode material is more unsafe than the charge state. Furthermore, the ex situ differential scanning calorimetry (DSC) spectrum of a discharge state at 2 V of layered P2-type NaCoO2 revealed a decreased onset temperature (DOT) at 141 °C with two pronounced exothermic peaks at 197 and 266 °C with a released higher total heat energy of 594 J g-1 than the charge state heat energy at 312 J g-1, attributed to the higher charge onset temperature (COT) at 191 °C. Thus, the observed higher heat energy and decreased onset temperature for the discharge state at 2 V is associated with the higher Na+ ion in the discharge state of the layered P2-type NaxCoO2 cathode than that of the pristine cathode, showcasing that the layered P2-type NaCoO2 cathode is unsafe at the discharged condition for sodium-ion batteries.

7.
Eur Neurol ; 83(4): 369-379, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877892

RESUMO

BACKGROUND: Cerebral sinus venous thrombosis (CSVT) is a relatively rare, potentially fatal neurological condition that can be frequently overlooked due to the vague nature of its clinical and radiological presentation. A literature search on PubMed using the keyword "Cerebral sinus venous thrombosis" was performed. We searched for the epidemiology, risk factors, pathophysiology, clinical features, diagnosis, and treatment of CSVT. All full-text articles in the last 10 years, in adults (>18 years), and the English language were included. We aim to give a comprehensive review of CSVT, with a primary focus on the management of the disease. SUMMARY: The literature search revealed 404 articles that met our criteria. CSVT is a relatively rare condition that accounts for approximately 1% of all forms of stroke. They can be subdivided into acute, subacute, and chronic forms based on the time of onset of clinical symptoms. It is a multifactorial disease, and the major forms of clinical presentation include isolated intracranial hypertension syndrome, focal neurological deficits, and cavernous sinus syndrome. MRI with magnetic resonance venogram (MRV) is considered the gold standard for diagnosis. Anticoagulation with heparin or low-molecular-weight heparin is the mainstay of treatment. Endovascular management is indicated for those cases with severe symptoms or worsening of symptoms despite anticoagulation therapy. Favorable outcomes have been reported in patients who receive early diagnosis and treatment. CONCLUSION: CSVT is a potentially fatal neurological condition that is often under-diagnosed due to its nonspecific presentation. Timely diagnosis and treatment can reduce morbidity and mortality, remarkably improving the outcome in affected individuals.


Assuntos
Trombose dos Seios Intracranianos/diagnóstico , Trombose dos Seios Intracranianos/patologia , Trombose dos Seios Intracranianos/terapia , Adulto , Feminino , Humanos , Masculino , Fatores de Risco
8.
Saudi J Biol Sci ; 27(2): 751-756, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32210696

RESUMO

Fungal keratitis caused by the species of Aspergillus is a common and leading problem in developing countries like India. In this study, a total of 135 isolates from Aspergillus keratitis were studied by sequence analyses of the internal transcribed spacer (ITS) region performed by nucleotide-nucleotide BLAST analysis followed by the initial identification of the isolates based on conidial and colony morphology. The sequence analysis revealed several unusual species which were never reported in eye infections such as A. tamrii, A. tubingensis, A. braslliensis, A. nomius, A. pseudonomius, A. sydowii, Eurotium amstelodami. The sequence analysis of the ITS region; the ß-tubulin and calmodulin genes brought out the genetic diversity among the isolates as the study intended to locate a more sensitive target sequence to study genetic diversity among a set of test fungal isolates. The PCR amplified sequences of the test isolates of the study as well as sequences belonging to section Flavi obtained from Genbank database were compared and analyzed along with three standard isolates by phylogenetic tree (Neighbor-joining) as to find out a target region/gene that could produce a better resolution to differentiate the isolates. Accordingly, the calmodulin gene had provided better resolution compared to ITS and ß-tubulin to study the diversity among the test Aspergillus species isolated from fungal corneal ulcer.

9.
ACS Appl Mater Interfaces ; 9(12): 10618-10625, 2017 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-28277643

RESUMO

Sodium-ion batteries are now close to replacing lithium-ion batteries because they provide superior alternative energy storage solutions that are in great demand, particularly for large-scale applications. To that end, the present study is focused on the properties of a new type of dual-electrode material, Na0.5Ni0.25Mn0.75O2, synthesized using a mixed hydroxy-carbonate route. Cyclic voltammetry confirms that redox couples, at high and low voltage ranges, are facilitated by the unique features and properties of this dual-electrode, through sodium ion deintercalation/intercalation into the layered Na0.5Ni0.25Mn0.75O2 material. This material provides superior performance for Na-ion batteries, as evidenced by the fabricated sodium cell that yielded initial charge-discharge capacities of 125/218 mAh g-1 in the voltage range of 1.5-4.4 V at 0.5 C. At a low voltage range (1.5-2.6 V), the anode cell delivered discharge-charge capacities of 100/99 mAh g-1 with 99% capacity retention, which corresponds to highly reversible redox reaction of the Mn4+/3+ reduction and the Mn3+/4+ oxidation observed at 1.85 and 2.06 V, respectively. The symmetric Na-ion cell, fabricated using Na0.5Ni0.25Mn0.75O2, yielded initial charge-discharge capacities of 196/187 µAh at 107 µA. These results encourage the further development of new types of futuristic sodium-ion-battery-based energy storage systems.

10.
J Clin Diagn Res ; 9(4): DD03-4, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26023553

RESUMO

Graphium eumorphum is rarely associated with mycotic keratitis. We report the case of a 30-year-old female presented with complaints of redness and defective vision in the left eye for one month. Gram staining and 10% KOH wet mount of corneal smears revealed fungal filaments. On potato dextrose agar, fast growing greyish white colonies turning grayish black on maturity was obtained. Lactophenol cotton blue (LPCB) staining confirmed the isolate as Graphium eumorphum. The infection was resolved with the combination of natamycin, econazole and itraconazole.

11.
Cornea ; 28(8): 951-4, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19654512

RESUMO

PURPOSE: To report 2 cases of keratomycosis caused by Aspergillus tubingensis. METHODS: The therapeutic courses were recorded for 2 male patients, 52 and 78 years old, with fungal keratitis caused by black Aspergillus strains. Morphological examination of the isolates was carried out on malt extract agar plates. A segment of the beta-tubulin gene was used for molecular identification. Antifungal susceptibilities were determined by the E test method for molds and the broth microdilution technique National Committee for Clinical Laboratory Standards M38-A. RESULTS: A 52-year-old man presented with complaints of pain and redness in the right eye. The patient was successfully treated with natamycin and econazole eyedrops, itraconazole eye ointment, and oral ketoconazole. A 78-year-old man presented with total corneal necrosis in the right eye. A therapeutic keratoplasty was performed, and topical natamycin and econazole were applied. At the postoperative visit after 3 weeks, almost the full corneal graft was clear with formed anterior chamber. Black Aspergillus strains were isolated from the corneal scrapings of both cases and initially identified as Aspergillus niger based on culture characteristics. Sequence analysis of a segment of the beta-tubulin gene revealed that the isolates are representatives of A. tubingensis. CONCLUSIONS: Aspergillus tubingensis is closely related with A. niger, the differentiation of these 2 species is difficult by classical morphological criteria. To our knowledge, the presented cases of fungal keratitis are the first reports on ocular infection caused by A. tubingensis.


Assuntos
Aspergilose , Ceratite/microbiologia , Administração Oral , Idoso , Antifúngicos/administração & dosagem , Aspergilose/tratamento farmacológico , Aspergilose/microbiologia , Aspergillus/classificação , Aspergillus/isolamento & purificação , Transplante de Córnea , Quimioterapia Combinada , Econazol/administração & dosagem , Humanos , Ceratite/cirurgia , Cetoconazol/administração & dosagem , Masculino , Pessoa de Meia-Idade , Natamicina/administração & dosagem , Soluções Oftálmicas
12.
Indian J Ophthalmol ; 56(1): 70-2, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18158410

RESUMO

In this case report, we describe the rare occurrence of bilateral conjunctival retention cysts in a child with Stevens-Johnson syndrome. The case was managed conservatively as there were no functional or cosmetic problems.


Assuntos
Doenças da Túnica Conjuntiva/etiologia , Cistos/etiologia , Síndrome de Stevens-Johnson/complicações , Criança , Doenças da Túnica Conjuntiva/patologia , Doenças da Túnica Conjuntiva/terapia , Cistos/patologia , Cistos/terapia , Humanos , Masculino
13.
Am J Ophthalmol ; 144(1): 144-6, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17601443

RESUMO

PURPOSE: To analyze cases with posttraumatic lenticular abscess and study the etiology, clinical presentation, management, and outcome. DESIGN: Retrospective case series. METHODS: Seventeen eyes of 17 patients with traumatic lenticular abscesses were managed with extracapsular cataract extraction after aspirating the abscess. RESULTS: The mean age of the patients was 40.3 years, and males constituted 82%. The mean time to presentation after injury was 14.35 days (range, one to 60 days), and the patients had a mean follow-up of 125.94 days (range, 21 to 300 days). Culture of the lenticular abscess revealed bacterial growth in eight cases (47%) and fungi in four cases (23.5%). In five (29.4%) cases, culture was negative. Staphylococcus epidermidis grew in seven cases (41%). Thirteen eyes (77%) had best-corrected visual acuity better than 20/120. CONCLUSIONS: Surgical removal of the abscess, with systemic and local antimicrobial treatment is effective in cases of posttraumatic intralenticular abscess.


Assuntos
Abscesso/etiologia , Infecções Oculares Bacterianas/etiologia , Infecções Oculares Fúngicas/etiologia , Ferimentos Oculares Penetrantes/complicações , Doenças do Cristalino/etiologia , Cristalino/lesões , Abscesso/terapia , Adulto , Antibacterianos/uso terapêutico , Extração de Catarata , Terapia Combinada , Infecções Oculares Bacterianas/terapia , Infecções Oculares Fúngicas/terapia , Ferimentos Oculares Penetrantes/terapia , Feminino , Humanos , Doenças do Cristalino/terapia , Implante de Lente Intraocular , Masculino , Estudos Retrospectivos , Resultado do Tratamento
14.
Indian J Ophthalmol ; 54(2): 129-31, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16770035

RESUMO

Toxoplasma gondii is a protozoan parasite that infects up to a third of the world's population. Infection is mainly acquired by ingestion of food that is contaminated with oocysts. We report an outbreak of ocular toxoplasmosis, which is an acute acquired type rather than reactivation of congenital toxoplasmosis. Our preliminary investigation points to municipal water contamination. This outbreak only proves the need of an effective public health system and health education in curtailing any outbreak.


Assuntos
Surtos de Doenças , Toxoplasmose Ocular/epidemiologia , Adolescente , Adulto , Idoso , Animais , Anticorpos Antiprotozoários/análise , Criança , Pré-Escolar , Feminino , Humanos , Índia/epidemiologia , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Toxoplasma/imunologia , Toxoplasmose Ocular/parasitologia
15.
Ann Acad Med Singap ; 35(3): 185-9, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16625268

RESUMO

INTRODUCTION: Corneal infection is the most common cause of profound ocular morbidity leading to blindness worldwide. Corneal infection in children is difficult to diagnose and treat, as they are unwilling and sometimes unable to cooperate during active management. This study analyses the prevalence, microbiology, demography, therapeutic and visual outcome of infectious microbial keratitis in the paediatric age group seen at a tertiary eye care hospital in south India. MATERIALS AND METHODS: A retrospective review of all cases presenting with keratitis to the ocular microbiology and cornea service at Aravind Eye Hospital, Coimbatore, from February 1997 to January 2004, was done to screen the patients for microbial keratitis. Their records were further analysed for clinical and microbiological details. Cases with culture-proven non-viral keratitis in children

Assuntos
Infecções Oculares Bacterianas , Infecções Oculares Fúngicas , Ceratite , Adolescente , Criança , Pré-Escolar , Infecções Oculares Bacterianas/diagnóstico , Infecções Oculares Bacterianas/terapia , Infecções Oculares Bacterianas/transmissão , Infecções Oculares Fúngicas/diagnóstico , Infecções Oculares Fúngicas/terapia , Infecções Oculares Fúngicas/transmissão , Feminino , Humanos , Índia , Lactente , Ceratite/diagnóstico , Ceratite/etiologia , Ceratite/microbiologia , Ceratite/terapia , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...