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1.
Soft Matter ; 20(5): 952-958, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38088860

RESUMEN

We classify native and chemically modified red blood cells with an AI based video classifier. Using TensorFlow video analysis enables us to capture not only the morphology of the cell but also the trajectories of motion of individual red blood cells and their dynamics. We chemically modify cells in three different ways to model different pathological conditions and obtain classification accuracies for all three classification tasks of more than 90% between native and modified cells. Unlike standard cytometers that are based on immunophenotyping our microfluidic cytometer allows to rapidly categorize cells without any fluorescence labels simply by analysing the shape and flow of red blood cells.


Asunto(s)
Eritrocitos , Microfluídica , Citometría de Flujo , Aprendizaje Automático , Movimiento (Física)
2.
Pestic Biochem Physiol ; 194: 105524, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37532341

RESUMEN

Silicon is known for mitigating the biotic and abiotic stresses of crop plants. Many studies have proved beneficial effects of bulk silicon against biotic stresses in general and insect pests in particular. However, the beneficial effects of silica nanoparticles in crop plants against insect pests were barely studied and reported. By virtue of its physical and chemical nature, silica nanoparticles offer various advantages over bulk silicon sources for its applications in the field of insect pest management. Silica nanoparticles can act as insecticide for killing target insect pest or it can act as a carrier of insecticide molecule for its sustained release. Silica nanoparticles can improve plant resistance to insect pests and also aid in attracting natural enemies via enhanced volatile compounds emission. Silica nanoparticles are safe to use and eco-friendly in nature in comparison to synthetic pesticides. This review provides insights into the applications of silica nanoparticles in insect pest management along with discussion on its synthesis, side effects and future course of action.


Asunto(s)
Insecticidas , Nanopartículas , Animales , Insecticidas/farmacología , Dióxido de Silicio/farmacología , Silicio , Insectos , Control de Plagas , Plantas , Control Biológico de Vectores
3.
Mol Cell Biochem ; 414(1-2): 13-22, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26833194

RESUMEN

Colorectal cancer is a critical health concern because of its incidence as the third most prevalent cancer in the world. Currently, 5-fluorouracil (5-FU), 6-thioguanine, and certain other genotoxic agents are mainstays of treatment; however, patients often die due to emergence of resistant population. Curcumin, a bioactive compound derived from the dietary turmeric (Curcuma longa) is an effective anticancer, anti-inflammatory, and antioxidant agent. Previously, we reported that human colorectal cancer cell lines compromised for mismatch repair (MMR) function exhibit heightened sensitivity to curcumin due to sustained curcumin-induced unrepaired DNA damage compared to proficient population counterparts. In this report, we show that the protein levels of gadd45α, whose transcript levels are increased during DNA damage and stress signals, are upregulated following curcumin treatment in a dose- and time-dependent manner. We further observed that cells compromised for Mlh1 function (HCT116 + Ch2) displayed ~twofold increased GADD45α upregulation compared to similarly treated proficient counterparts (HCT116 + Ch3). Similarly, suppression of Mlh1 using ShRNA increased GADD45α upregulation upon curcumin treatment. On the other hand, suppression of GADD45α using SiRNA-blocked curcumin-induced cell death induction in Mlh1-deficient cells. Moreover, inhibition of Abl through ST571 treatment and its downstream effector JNK through SP600125 treatment blocked GADD45α upregulation and cell death triggered by curcumin. Collective results lead us to conclude that GADD45α modulates curcumin sensitivity through activation of c-Abl > JNK signaling in a mismatch repair-dependent manner.


Asunto(s)
Disparidad de Par Base , Proteínas de Ciclo Celular/fisiología , Curcumina/farmacología , Reparación del ADN , MAP Quinasa Quinasa 4/metabolismo , Proteínas Nucleares/fisiología , Proteínas Proto-Oncogénicas c-abl/metabolismo , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 9/metabolismo , Línea Celular Tumoral , Neoplasias Colorrectales/enzimología , Neoplasias Colorrectales/patología , Humanos
4.
Cell Mol Biol (Noisy-le-grand) ; 63(1): 17-22, 2016 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-28234620

RESUMEN

ß-Catenin has been implicated in various developmental and physiological processes. Defective Wnt signaling can result in different cardiac and vascular abnormalities and is activated under pathological conditions such as inflammation and obesity. In this study, roles of ß-catenin in inflammation in cardiomyocytes were investigated. 10 samples from hearts of patients with acute infarction and 10 from normal ones were collected in order to access roles of ß-catenin in cardiomyocytes. H9c2 cardiomyoblasts and primary neonatal rat cardiomyocytes were transfected with porcine cytomegalovirus (pCMV)-ß-catenin plasmid in order to overexpress ß-catenin. Protein level of ß-catenin protein was increased in human acute infarction tissues compared to ones from normal patients. The transcription factor had increased nuclear localization in cardiomyocytes of the Wistar rats with cardiac hypertension. Furthermore, expression of fibrosis protein markers increased. Protein expression of ß-catenin was increased in human acute infarction inflammatory heart tissues and in hearts of inflammatory obesity rats. After pCMV-ß-catenin plasmid was transfected in a dose-dependent manner, inflammation protein markers, TNF-α and IL-8, were upregulated in hypertensive neonatal rat cardiomyocytes and H9c2 cardiomyoblasts. In addition, overexpression of ß-catenin induced activation and nuclear localization of NF-κB. Therefore, ß-catenin is a potential molecular target for treatment of inflammation and fibrosis in cardiomyocytes.


Asunto(s)
Citocinas/metabolismo , FN-kappa B/metabolismo , beta Catenina/metabolismo , Animales , Células Cultivadas , Humanos , Inmunohistoquímica , Interleucina-8/metabolismo , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Miocardio/metabolismo , Miocardio/patología , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Plásmidos/metabolismo , Ratas , Ratas Wistar , Factor de Necrosis Tumoral alfa/metabolismo , beta Catenina/genética
5.
Nat Genet ; 33(1): 80-4, 2003 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-12447371

RESUMEN

Defective S-phase checkpoint activation results in an inability to downregulate DNA replication following genotoxic insult such as exposure to ionizing radiation. This 'radioresistant DNA synthesis' (RDS) is a phenotypic hallmark of ataxia-telangiectasia, a cancer-prone disorder caused by mutations in ATM. The mismatch repair system principally corrects nucleotide mismatches that arise during replication. Here we show that the mismatch repair system is required for activation of the S-phase checkpoint in response to ionizing radiation. Cells deficient in mismatch repair proteins showed RDS, and restoration of mismatch repair function restored normal S-phase checkpoint function. Catalytic activation of ATM and ATM-mediated phosphorylation of the protein NBS1 (also called nibrin) occurred independently of mismatch repair. However, ATM-dependent phosphorylation and activation of the checkpoint kinase CHK2 and subsequent degradation of its downstream target, CDC25A, was abrogated in cells lacking mismatch repair. In vitro and in vivo approaches both show that MSH2 binds to CHK2 and that MLH1 associates with ATM. These findings indicate that the mismatch repair complex formed at the sites of DNA damage facilitates the phosphorylation of CHK2 by ATM, and that defects in this mechanism form the molecular basis for the RDS observed in cells deficient in mismatch repair.


Asunto(s)
Disparidad de Par Base/genética , Reparación del ADN , Proteínas de Unión al ADN , Proteínas Proto-Oncogénicas , Tolerancia a Radiación/genética , Fase S , Proteínas Adaptadoras Transductoras de Señales , Proteínas de la Ataxia Telangiectasia Mutada , Proteínas Portadoras , Proteínas de Ciclo Celular/metabolismo , Quinasa de Punto de Control 2 , Reparación del ADN/efectos de la radiación , Replicación del ADN/efectos de la radiación , Activación Enzimática , Eliminación de Gen , Humanos , Modelos Biológicos , Homólogo 1 de la Proteína MutL , Proteína 2 Homóloga a MutS , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Fosforilación , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Radiación Ionizante , Fase S/efectos de la radiación , Células Tumorales Cultivadas , Proteínas Supresoras de Tumor , Fosfatasas cdc25/metabolismo
6.
Exp Cell Res ; 315(18): 3163-75, 2009 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-19766113

RESUMEN

Agents inducing O(6)-methylguanine (O(6)MeG) in DNA such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) are cytotoxic and a deficiency in mismatch repair (MMR) results in lack of sensitivity to this genotoxin (termed alkylation tolerance). Here, we show that ING2, a member of the inhibitor of growth family, is required for cell death induced by MNNG. We further observe that MNNG treatment increases cellular protein levels of ING2 that is dependent on intact MMR function and that MNNG-induced ING2 localizes and associates with p73alpha in the nucleus. Suppression of ING2 by short hairpin RNA (shRNA) in MMR-proficient colorectal cancer cells decreased its sensitivity to MNNG and, in addition, abrogated MNNG-induced stabilization and acetylation of p73alpha. Interestingly, suppression of p73alpha had a greater impact on MNNG-induced cell death than ING2 leading us to conclude that ING2 regulates the cell death response, in part, through p73alpha. Inhibition of c-Abl by STI571 or suppression of c-Abl expression by shRNA blocked ING2 induction and p73alpha acetylation induced by this alkylator. Similarly, suppression of MMR (MLH1) by shRNA abrogated ING2 induction/p73alpha acetylation. Taken together, these results demonstrate that MLH1/c-Abl-dependent activation of ING2>p73alpha signaling regulates cell death triggered by MNNG and further suggests that dysregulation of this event may, in part, be responsible for alkylation tolerance observed in MMR compromised cells.


Asunto(s)
Alquilantes/toxicidad , Apoptosis , Carcinógenos/toxicidad , Reparación de la Incompatibilidad de ADN , Proteínas de Unión al ADN/metabolismo , Proteínas de Homeodominio/metabolismo , Metilnitronitrosoguanidina/toxicidad , Proteínas Nucleares/metabolismo , Proteínas Proto-Oncogénicas c-abl/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas Adaptadoras Transductoras de Señales/efectos de los fármacos , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Antineoplásicos/farmacología , Benzamidas , Proteínas de Unión al ADN/antagonistas & inhibidores , Células HeLa , Proteínas de Homeodominio/agonistas , Humanos , Mesilato de Imatinib , Homólogo 1 de la Proteína MutL , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/efectos de los fármacos , Oligonucleótidos/metabolismo , Piperazinas/farmacología , Proteínas Proto-Oncogénicas c-abl/efectos de los fármacos , Pirimidinas/farmacología , ARN Interferente Pequeño/metabolismo , Receptores Citoplasmáticos y Nucleares/agonistas , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Transfección , Proteína Tumoral p73 , Proteína p53 Supresora de Tumor/efectos de los fármacos , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/agonistas , Proteínas Supresoras de Tumor/antagonistas & inhibidores
7.
Radiat Prot Dosimetry ; 189(2): 182-189, 2020 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-32239152

RESUMEN

The radon (222Rn) and thoron (220Rn) fluxes from the soil and building materials are the major contributors to their indoor levels. Hence, the measurement of radon and thoron exhalation rates from the source matrix becomes the foremost step in controlling the indoor radon and thoron exposure. It is a challenge to measure the exhalation rates without disturbing the natural conditions. The back-diffusion phenomenon modifies the exhalation rate. The work presented here is to measure the back-diffusion coefficient and takes it into consideration while estimating the exhalation rate. For radon measurements, the back-diffusion coefficient and the free exhalation rates were simultaneously estimated by adopting a novel methodology. The leak rate of the experimental setup measured by this methodology was agreeable with the value measured by adopting the standard technique. In the case of thoron, the back-diffusion effect was found to be negligible for the present experimental conditions and it is duly explained. The above results were obtained by analyzing two soil samples with high 238U and 232Th content collected from monazite-rich coastal area.


Asunto(s)
Contaminantes Radiactivos del Aire , Contaminación del Aire Interior , Monitoreo de Radiación , Radón , Uranio , Contaminantes Radiactivos del Aire/análisis , Contaminación del Aire Interior/análisis , Espiración , Radón/análisis , Torio
8.
Radiat Prot Dosimetry ; 187(4): 482-498, 2019 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-31711198

RESUMEN

A study on radionuclide distribution along coastal stretch in high background areas is constantly attracted to many researchers around the world. In the present study, the concentration of radionuclides in beach sands along the southeast coastal region of India has been studied in detail. Concentration of radionuclides is measured using gamma spectrometry at 148 pre-determined locations. It is found that 238U and 232Th concentrations are varying in the range from 3 (BDL) to 298.9 and 1150.2 Bq kg-1, respectively. Concentration of 40K in beach sand varied from 11 to 1743.4 Bq kg-1. The measured activity levels of radionuclides were compared with earlier studies carried out by various researchers in the same region under study. The related radiological parameters of interest were also determined and compared with the internationally recommended values. With an increase in emphasis on quality in dose assessment methods, dose to human population living in the vicinity requires uncertainty evaluation, which is carried out by taking into account variation in the activity values. This study would serve as a baseline radiological mapping for the southeast coast region of India for environmental impact assessment prior to plan of nuclear facility in the future.


Asunto(s)
Monitoreo de Radiación/métodos , Contaminantes Radiactivos del Suelo/análisis , Torio/análisis , Uranio/análisis , Ambiente , Humanos , India , Espectrometría gamma
9.
Radiat Prot Dosimetry ; 185(1): 87-95, 2019 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-30561717

RESUMEN

The activity concentration of 238U, 232Th and 40K were measured in the soil samples collected from Fast Reactor Fuel Cycle Facility (FRFCF) site, using high-resolution gamma-ray spectrometry. This study is aimed to establish the baseline data of naturally occurring radionuclides within the site. The average activity concentrations were found to be 416.5, 61.7 and 622.3 Bq kg-1 for 40K, 238U and 232Th, respectively. The activity concentrations and its radiological indices were evaluated and were compared with the international values reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The ratio of 40K/232Th and 40K /238U were calculated, which indicates the presence of 5.79 and 2.69 times more K-bearing minerals as compared with Th and U-bearing minerals in the soil samples, respectively. The study provides baseline information on concentration of radionuclides and background radiological assessment of the FRFCF site.


Asunto(s)
Radiación de Fondo , Radioisótopos de Potasio/análisis , Monitoreo de Radiación/métodos , Contaminantes Radiactivos del Suelo/análisis , Torio/análisis , Uranio/análisis , India , Dosis de Radiación , Espectrometría gamma
10.
Radiat Prot Dosimetry ; 187(2): 139-153, 2019 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-31135907

RESUMEN

India is the second largest seafood producer in the world marketing more than 7000 edible species. In this regard, commendable studies have been conducted since the 1970s by different research groups and more data are reported. In this work, all the studies on 210Po and 210Pb measurements in abiotic and biotic components of India have been combined and reviewed. The concentrations of 210Po and 210Pb are estimated by radiochemical separation followed by alpha counting. Grain size, season, Tsunami waves and place of sampling have a decisive bearing on 210Po and 210Pb concentration in abiotic components. Plankton shows a higher Kd factor (104) compared to seaweeds and sea grass (103). Pond ecosystems recorded the highest Kd factor (4·3 × 104) compared to other freshwater and marine ecosystems. Bioaccumulation of 210Po and 210Pb varies with respect to variety of seafood. The committed effective dose (CED) calculated for shellfish species maintained a higher range of 2.5 × 10-2 mSv/y to 9.8 × 10-1 mSv/y and for fish species fluctuated from 3.8 × 10-4 mSv/y to 2.0 × 10-1 mSv/y. The studies conducted so far are scattered, and need to be gathered for future reference and planning (i.e. There is not much information available for Kerala, Karnataka, Maharashtra, Gujarat, Andhra, West Bengal and Odessa coast). Therefore, it is strongly recommended that further and more complete research is undertaken to study the bioaccumulation of 210Po and 210Pb from seafood. Overall, the present review concludes that Indian seafood is radiologically safe.


Asunto(s)
Contaminación Radiactiva de Alimentos/análisis , Radioisótopos de Plomo/análisis , Polonio/análisis , Alimentos Marinos/análisis , Animales , Humanos , Radioisótopos de Plomo/administración & dosificación , Polonio/administración & dosificación , Dosis de Radiación
11.
Appl Radiat Isot ; 152: 127-134, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31299449

RESUMEN

This paper discusses the modeling of HPGe detector used in waste assay system using Monte Carlo code FLUKA to determine its detection limits. The modeled detector is validated using experimental point sources efficiencies in the energy range 60 keV-2000 keV. The numerical estimation of efficiency values for 239Pu present inside a 230 L cotton filled waste drum at various locations along the axis of the detector is discussed. Estimation of the minimum detectable activity (MDA) for 239Pu at these locations in the presence of 1 MBq of 137Cs/60Co again along the axis of the detector is examined. The efficiency of 239Pu decreases from 6.1 × 10-10 to 7.5 × 10-11 cps/Bq as the location of 239Pu moves away from the detector. MDA of 239Pu increases as the position of 239Pu and 137Cs/60Co in the waste drum shifts away from the detector while it decreases as the location of 137Cs/60CO moves away from 239Pu along measurement axis. It is observed that for all locations of 137Cs/60Co with 239Pu located up to 200 mm from the edge of the drum, the detection limit is within 140.3 mg (allowed limit).

12.
Rev Sci Instrum ; 79(2 Pt 2): 02C702, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18315255

RESUMEN

A novel electron cyclotron resonance x-ray source is constructed based on the ECR technique. In this paper, the possibility of using the ECR x-ray source for producing UV rays by optimizing the plasma parameters is explored. X-ray and UV emissions from the ECR x-ray source are carried out for argon, nitrogen, and CO(2) plasma. The x-ray spectral and dose measurements are carried with NaI(Tl) based spectrometer and dosimeter, respectively. For UV measurement, a quartz window arrangement is made at the exit port and the UV intensity is measured at 5 cm from the quartz plate using UV meter. The x-ray and UV emissions are carried out for different microwave power levels and gas pressures. The x-ray emission is observed in the pressure range < or =10(-5) Torr, whereas the UV emission is found to be negligible for the gas pressures <10(-5) Torr and it starts increasing in the pressure range between 10(-5) and 10(-3) Torr. At high-pressure range, collision frequency of electron-atom is large which leads to the higher UV flux. At low pressure, the electron-atom collision frequency is low and hence the electrons reach high energy and by hitting the cavity wall produces higher x-ray flux. By choosing proper experimental conditions and plasma gas species, the same source can be used as either an x-ray source or an UV source.

13.
Rev Sci Instrum ; 79(2 Pt 2): 02A324, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18315114

RESUMEN

From the ECR plasma, hot electrons leak across the magnetic lines of force and by striking the plasma chamber produce bremsstrahlung x-rays. The wall bremsstrahlung gives information on the confinement status of hot electron. In our studies, experimental measurements are carried out in NANOGAN electron cyclotron resonance (ECR) ion source for the wall bremsstrahlung x-rays and the results are presented. While optimizing a particular charge state in ECR ion source, experimental parameters are adjusted to get a maximum current. The wall bremsstrahlung components are studied in these cases for understanding the hot electron confinement conditions.


Asunto(s)
Ciclotrones/instrumentación , Electrones , Radiometría/métodos , Espectrometría por Rayos X/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Dosis de Radiación
14.
Mol Biol Cell ; 16(3): 1513-26, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15647386

RESUMEN

SN1 DNA methylating agents such as the nitrosourea N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) elicit a G2/M checkpoint response via a mismatch repair (MMR) system-dependent mechanism; however, the exact nature of the mechanism governing MNNG-induced G2/M arrest and how MMR mechanistically participates in this process are unknown. Here, we show that MNNG exposure results in activation of the cell cycle checkpoint kinases ATM, Chk1, and Chk2, each of which has been implicated in the triggering of the G2/M checkpoint response. We document that MNNG induces a robust, dose-dependent G2 arrest in MMR and ATM-proficient cells, whereas this response is abrogated in MMR-deficient cells and attenuated in ATM-deficient cells treated with moderate doses of MNNG. Pharmacological and RNA interference approaches indicated that Chk1 and Chk2 are both required components for normal MNNG-induced G2 arrest. MNNG-induced nuclear exclusion of the cell cycle regulatory phosphatase Cdc25C occurred in an MMR-dependent manner and was compromised in cells lacking ATM. Finally, both Chk1 and Chk2 interact with the MMR protein MSH2, and this interaction is enhanced after MNNG exposure, supporting the notion that the MMR system functions as a molecular scaffold at the sites of DNA damage that facilitates activation of these kinases.


Asunto(s)
Disparidad de Par Base , Reparación del ADN , Proteínas de Unión al ADN/fisiología , Fase G2 , Proteínas Quinasas/fisiología , Proteínas Serina-Treonina Quinasas/fisiología , Proteínas Proto-Oncogénicas/fisiología , Estaurosporina/análogos & derivados , División Celular , Núcleo Celular/metabolismo , Células Cultivadas , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Quinasa de Punto de Control 2 , Daño del ADN , Metilación de ADN , Proteínas de Unión al ADN/metabolismo , Relación Dosis-Respuesta a Droga , Electroforesis en Gel de Poliacrilamida , Citometría de Flujo , Humanos , Immunoblotting , Inmunoprecipitación , Metilnitronitrosoguanidina/farmacología , Proteína 2 Homóloga a MutS , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/genética , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Estaurosporina/farmacología , Fracciones Subcelulares , Factores de Tiempo
15.
Rev Sci Instrum ; 89(11): 113117, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30501299

RESUMEN

The ability to detect and quantify scales in pipes has been an important yardstick for efficient transfer of fluids in domestic as well as in application related industries. Knowledge of different kinds of scales formed has become a precondition for trouble-shooting in operational lines. In this paper, collimated Compton backscattered gamma rays from a radioactive source have been used to inspect the scales by automatic scanning in steps along the axial direction of different pipes. The methodology has been extended for the quantification of scales that prevails in the real functionality of extensive usage of fluids. To aid for descaling processes, the desideratum is the density determination of scales and this parameter is quantified non-destructively and is also validated with the standard density. The described non-intrusive gamma ray densitometry is quite promising, efficient and has highly reliable results for scale detection with the squared correlation coefficient of 0.98. The proposed technique shows a better linearity than the gammatography technique.

16.
Radiat Prot Dosimetry ; 179(2): 125-135, 2018 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-29069491

RESUMEN

This review deals with natural radioactivity variation along the southeast coast of Tamil Nadu for the past four decades (1974-2016). About 40 research works have been conducted along the coast since 1974 in various environmental matrices using a variety of experimental methods. For these measurements researchers are adopted different experimental methods. The measured gamma dose rate ranged from 30 to 8700 nGy/h. The mean specific activity of 238U, 232Th and 40K was found to be 58.8 ± 28.7, 465.2 ± 147.3 and 311.2 ± 27.8 Bq/kg, respectively. The calculated annual exposure rate ranged from 0.29 to 12.8 mSv/y with the mean value of 3.7 mSv/y which is above the global average of 2.4 mSv/y as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (Report to General Assembly, Annex B Exposures of the public and workers from various sources of radiation. United Nations, New York (2008)). Plant food items recorded low 210Po activities as compared to seafood organisms. Grain size, season and place of sampling have a decisive bearing on coastal radioactivity. Therefore, it is concluded from the review data that there is an appreciable elevation in background radiation level in the coastal region. This review suggests that new radiological surveys using improved methodology that cover the entire coastal stretch are needed.


Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Radiación de Fondo , Radioisótopos de Plomo/análisis , Polonio/análisis , Radioisótopos de Potasio/análisis , Contaminantes Radiactivos del Suelo/análisis , Torio/análisis , Uranio/análisis , Contaminantes Radiactivos del Agua/análisis , Animales , Rayos gamma , Humanos , India , Monitoreo de Radiación
17.
SLAS Technol ; 23(6): 614-623, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-29746801

RESUMEN

Contact heat evoked potentials (CHEPs) are recorded from the brain by giving thermal stimulations through heating pads kept on the surface of the skin. CHEP signals have crucial diagnostic implications in human pain activation studies. This work proposes a novel design of a digital proportional integral (PI) controller based on Arduino microcontroller with a view to explore the suitability of an electric heating pad for use as a thermode in a custom-made, cost-effective CHEP stimulator. The purpose of PI controller is to set, regulate, and deliver desired temperatures on the surface of the heating pad in a user-defined pattern. The transfer function of the heating system has been deduced using the parametric system identification method, and the design parameters of the controller have been identified using the root locus technique. The efficiency of the proposed PI controller in circumventing the well-known integrator windup problem (error in the integral term builds excessively, leading to large transients in the controller output) in tracking the reference input and the controller effort (CE) in rejecting output disturbances to maintain the set temperature of the heating pad have been found to be superior compared with the conventional PI controller and two of the existing anti-windup models.


Asunto(s)
Diseño de Equipo , Calefacción/métodos , Automatización de Laboratorios/instrumentación , Automatización de Laboratorios/métodos , Calefacción/instrumentación , Humanos , Temperatura
18.
Appl Radiat Isot ; 133: 75-80, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29294418

RESUMEN

The exhalation of radon (222Rn) and thoron (220Rn) from a porous matrix depends on the emanation of them from the grains by the recoil effect. The emanation factor is a quantitative estimate of the emanation phenomenon. The present study is to investigate the effect of grain size of the soil matrix on the emanation factor. Soil samples from three different locations were fractionated into different grain size categories ranging from <0.1 to 2mm. The emanation factors of each of the grain size range were estimated by measuring the mass exhalation rates of radon and thoron and the activity concentrations of 226Ra and 232Th. The emanation factor was found to increase with decrease in grain size. This effect was made evident by keeping the parent radium concentration constant for all grain size fractions. The governing factor is the specific surface area of the soil samples which increases with decrease in grain size.

19.
Mol Cell Biol ; 16(7): 3361-9, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8668151

RESUMEN

The c-abl proto-oncogene encodes a nuclear tyrosine kinase that can phosphorylate the mammalian RNA polymerase II (RNAP II) on its C-terminal repeated domain (CTD) in vitro. Phosphorylation of the CTD has previously been shown to require the tyrosine kinase and the SH2 domain of Abl. We show here that a CTD-interacting domain (CTD-ID) at the C-terminal region of c-Abl is also required. Deletion of the CTD-ID causes the Km 0.4 microM to increase by 2 orders of magnitude. Direct binding of the CTD-ID to CTD and to RNAP II could be demonstrated in vitro. Phosphorylation of a recombinant glutathione S-transferase-CTD by c-Abl was observed in cotransfected COS cells. Mutant Abl proteins lacking the CTD-ID, while capable of autophosphorylation, neither phosphorylated nor associated with the glutathione S-transferase-CTD in vivo. Transient overexpression of c-Abl also led to a four- to fivefold increase in the phosphotyrosine content of the RNAP II large subunit. Moreover, the large subunit of RNAP II could be coprecipitated with c-Abl. Tyrosine phosphorylation of the coprecipitated RNAP II was again dependent on the presence of the CTD-ID in Abl. Finally, the ability of c-Abl to phosphorylate and associate with RNAP II could be correlated with the enhancement of transcription by c-Abl in transient cotransfection assays. Taken together, these observations demonstrate that c-Abl can function as a CTD kinase in vitro as well as in vivo.


Asunto(s)
Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-abl/metabolismo , ARN Polimerasa II/química , ARN Polimerasa II/metabolismo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Unión Competitiva , Neoplasias Óseas , Línea Celular , Chlorocebus aethiops , Secuencia de Consenso , Genes abl , Glutatión Transferasa , Humanos , Riñón , Cinética , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Osteosarcoma , Fosforilación , Fosfotirosina/análisis , Proto-Oncogenes Mas , Proteínas Recombinantes de Fusión/biosíntesis , Eliminación de Secuencia , Transcripción Genética , Transfección , Células Tumorales Cultivadas
20.
Mol Cell Biol ; 18(7): 4032-42, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9632788

RESUMEN

Growth suppression by the retinoblastoma protein (RB) is dependent on its ability to form complexes with transcription regulators. At least three distinct protein-binding activities have been identified in RB: the large A/B pocket binds E2F, the A/B pocket binds the LXCXE peptide motif, and the C pocket binds the nuclear c-Abl tyrosine kinase. Substitution of Trp for Arg 661 in the B region of RB (mutant 661) inactivates both E2F and LXCXE binding. The tumor suppression function of mutant 661 is not abolished, because this allele predisposes its carriers to retinoblastoma development with a low penetrance. In cell-based assays, 661 is shown to inhibit G1/S progression. This low-penetrance mutant also induces terminal growth arrest with reduced but detectable activity. We have constructed mutations that disrupt C pocket activity. When overproduced, the RB C-terminal fragment did not induce terminal growth arrest but could inhibit G1/S progression, and this activity was abolished by the C-pocket mutations. In full-length RB, the C-pocket mutations reduced but did not abolish RB function. Interestingly, combination of the C-pocket and 661 mutations completely abolished RB's ability to cause an increase in the percentage of cells in G1 and to induce terminal growth arrest. These results suggest that the A/B or C region can induce a prolongation of G1 through mechanisms that are independent of each other. In contrast, long-term growth arrest requires combined activities from both regions of RB. In addition, E2F and LXCXE binding are not the only mechanisms through which RB inhibits cell growth. The C pocket also contributes to RB-mediated growth suppression.


Asunto(s)
Proteínas Portadoras , Proteínas de Ciclo Celular , División Celular , Proteínas de Unión al ADN , Proteína de Retinoblastoma/metabolismo , Factores de Transcripción/metabolismo , Sitios de Unión , Clonación Molecular , ADN/metabolismo , Factores de Transcripción E2F , Fase G1 , Humanos , Mutagénesis , Proteínas Proto-Oncogénicas c-abl/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteína de Retinoblastoma/genética , Proteína 1 de Unión a Retinoblastoma , Fase S , Factor de Transcripción DP1 , Factores de Transcripción/genética , Células Tumorales Cultivadas
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