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1.
J Chem Phys ; 154(16): 164105, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33940806

RESUMEN

Thermal stability and pressure-dependent changes are key to molecular crystals and their properties. The determination of their thermal properties from ab initio methods is, however, a challenging task. While the low-frequency phonon spectrum related to intermolecular vibrations remains difficult to describe, the Quasi-Harmonic Approximation (QHA) also induces for molecular crystals a significant volume deviation, which makes their thermal behavior ill-determined. To overcome these difficulties, we consider a pragmatic energy correction (EC) that has long been used for atomic crystals, and we presently report the first ever use for molecular crystals. Applying the QHA in dispersion-corrected density functional theory (DFT-D) calculations with an ab initio parameterized EC, the resulting model can simultaneously and accurately derive thermal and mechanical properties of high-explosive molecular crystals. When compared to experiments, the mean absolute percent error of previous DFT-based thermomechanical models is 12% for mechanical and 31% for thermal properties. Our model performs significantly better and reduces these uncertainties to 4.1% and 9.8%, respectively. In particular, the agreement between our model and experiments for the thermal properties is three times better. This significant improvement greatly benefits the determination of thermomechanical properties such as the Grüneisen parameter and the shock properties. The method has been successfully applied to molecular crystals showing a large diversity of weak intermolecular interactions (ß-1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX), α-1,1-diamino-2,2-dinitroethylene (FOX-7), Triaminotrinitrobenzene (TATB), ε-Hexanitrohexaazaisowurtzitane (CL20), and Pentaerythritol tetranitrate (PETN)-I). Due to its accuracy and transferability, our model is expected to work for a large class of computationally designed molecular crystals and co-crystals, providing a basis for a predictive framework.

2.
J Appl Microbiol ; 129(3): 753-767, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32145053

RESUMEN

AIMS: To examine the modulation of the interacting partners of the calcineurin (CaN)-NFAT pathway in T cells during Cryptococcus neoformans fungal infection and post-T11TS immunotherapy. METHODS AND RESULTS: Wistar rats were infected with C. neoformans and followed by immunotherapy with immune-potentiator T11TS. T cells were analysed by flow cytometry, immunoblotting and nuclear translocation study. The signalling proteins LCK, FYN, LAT, PLCγ1 and CaN in T cells were regulated by C. neoformans infection resulting in reduced nuclear translocation of NFAT and IL-2 expression. Following T11TS immunotherapy, the expressions of the above-mentioned proteins were boosted and thus resulting in the clearance of C. neoformans from lung and spleen. CONCLUSIONS: The precise mechanism of suppression of the T-cell function by C. neoformans is still unknown. Previously, we have shown that T11TS positively regulates the function of T cells to abrogate glioma and other immunosuppressive conditions. T11TS immunotherapy increased the expression of the above signalling partners of the CaN-NFAT pathway in T cells and improved nuclear retention of NFAT. As a result, an increased IL-2 expression leads to activation and proliferation of T cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results demonstrate the role of T11TS in restoring the CaN-NFAT signalling pathway in T cells. It identifies T11TS as an immunotherapeutic agent with potential clinical outcomes to counteract C. neoformans infection.


Asunto(s)
Antígenos CD58/uso terapéutico , Calcineurina/metabolismo , Criptococosis/terapia , Factores de Transcripción NFATC/metabolismo , Linfocitos T/inmunología , Animales , Criptococosis/inmunología , Criptococosis/microbiología , Cryptococcus neoformans/efectos de los fármacos , Cryptococcus neoformans/inmunología , Inmunoterapia/métodos , Interleucina-2/metabolismo , Activación de Linfocitos/efectos de los fármacos , Ratas , Ratas Wistar , Ovinos , Transducción de Señal/efectos de los fármacos , Linfocitos T/metabolismo
3.
IEEE Trans Appl Supercond ; 29(5)2019 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-31360051

RESUMEN

Readout of a large, spacecraft-based array of superconducting transition-edge sensors (TESs) requires careful management of the layout area and power dissipation of the cryogenic-circuit components. We present three optimizations of our time- (TDM) and code-division-multiplexing (CDM) systems for the X-ray Integral Field Unit (X-IFU), a several-thousand-pixel-TES array for the planned Athena-satellite mission. The first optimization is a new readout scheme that is a hybrid of CDM and TDM. This C/TDM architecture balances CDM's noise advantage with TDM's layout compactness. The second is a redesign of a component: the shunt resistor that provides a dc-voltage bias to the TESs. A new layout and a thicker Pd-Au resistive layer combine to reduce this resistor's area by more than a factor of 5. Third, we have studied the power dissipated by the first-stage SQUIDs (superconducting quantum-interference devices) and the readout noise versus the critical current of the first-stage SqUIDs. As a result, the X-IFU TDM and C/TDM SQUIDs will have a specified junction critical current of 5 µA. Based on these design optimizations and TDM experiments described by Durkin, et al. (these proceedings), TDM meets all requirements to be X-IFU's backup-readout option. Hybrid C/TDM is another viable option that could save spacecraft resources.

4.
Artículo en Inglés | MEDLINE | ID: mdl-31160861

RESUMEN

Time-division multiplexing (TDM) is the backup readout technology for the X-ray Integral Field Unit (X-IFU), a 3,168-pixel X-ray transition-edge sensor (TES) array that will provide imaging spectroscopy for ESA's Athena satellite mission. X-0IFU design studies are considering readout with a multiplexing factor of up to 40. We present data showing 40-row TDM readout (32 TES rows + 8 repeats of the last row) of TESs that are of the same type as those being planned for X-IFU, using measurement and analysis parameters within the ranges specified for X-IFU. Singlecolumn TDM measurements have best-fit energy resolution of (1.91 ± 0.01) eV for the Al Kα complex (1.5 keV), (2.10 ± 0.02) eV for Ti Kα (4.5 keV), (2.23 ± 0.02) eV for Mn Kα (5.9 keV), (2.40 ± 0.02) eV for Co Kα (6.9 keV), and (3.44 ± 0.04) eV for Br Kα (11.9 keV). Three-column measurements have best-fit resolution of (2.03 ± 0.01) eV for Ti Kα and (2.40 ± 0.01) eV for Co Kα. The degradation due to the multiplexed readout ranges from 0.1 eV at the lower end of the energy range to 0.5 eV at the higher end. The demonstrated performance meets X-IFU's energy-resolution and energy-range requirements. True 40-row TDM readout, without repeated rows, of kilopixel scale arrays of X-IFU-like TESs is now under development.

5.
J Obstet Gynaecol ; 32(1): 14-25, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22185528

RESUMEN

In many recent studies in the developed world, the incidence of postpartum haemorrhage (PPH) has been rising, though the mortality has come down, suggesting improvement in the management of this condition. Since the publication of the RCOG guidelines in 2009 for management of PPH and the Sheffield guidelines for the use of Rusch balloon along with the initial small case series (Keriakos and Mukhopadhyay 2006), many units have introduced the guidelines into clinical practice. This has led to the reduction of surgical intervention in our unit. Major PPH accounted for 1.6% of the total deliveries in our hospital. Surgical interventions accounted for 7.8% of these cases and only 0.1% of the total deliveries. Risk factors for PPH were identified in 83%. In this paper, we reviewed the management of all patients who had major PPH and failed medical management over a period of about 4 years. All surgical interventions including Rusch balloon, B-Lynch suture, radiological interventions and hysterectomy were described. An update to Rusch balloon guidelines and Sheffield guidelines for management of major PPH are appended.


Asunto(s)
Histerectomía , Hemorragia Posparto/cirugía , Técnicas de Sutura , Taponamiento Uterino con Balón/instrumentación , Adulto , Femenino , Humanos , Incidencia , Hemorragia Posparto/epidemiología , Embarazo , Estudios Retrospectivos , Adulto Joven
6.
RSC Adv ; 12(48): 31282-31292, 2022 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-36349003

RESUMEN

Impact sensitivity engineering of high-energy molecular crystals requires accurate predictive models. For this purpose, the promising multi-phonon based approach is selected, assessing a bit more its strengths and weaknesses. Presently used with high-quality phonon calculations of 22 molecular crystals, using a physics-based criterion to determine the phonon bath extent, the resulting intrinsic shock sensitivity index (SSI) is compared to the most common marker of impact sensitivity, h 50, as determined from drop-weight impact tests. Selecting a data subset from experiments performed under very similar conditions (2.5 kg hammer with grit and 30-40 mg samples), the model can predict h 50 values for mono-molecular crystals with very good accuracy, including the ability to discriminate the polymorphs of HMX and CL20. This very good agreement validates an initial indirect up-pumping mechanism occurring under these conditions, where the doorway modes also interact with the phonon bath. However, the phonon bath criterion for mono-molecular crystals does not transfer well to cocrystals. Owing to the vibrational coupling of the co-molecules, it seems a broader phonon bath should be considered. Additionally recalling experimental uncertainty and various experimental factors affecting h 50 values for a given compounds, we recommend that the density of the sample, granularity and morphology be systematically considered and reported along with measurements, which will in turn allow for more systematic data and predictive capabilities for sensitivity models.

7.
Sci Rep ; 11(1): 524, 2021 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-33436754

RESUMEN

Band structure tailoring has been a great avenue to achieve the half-metallic electronic ground state in materials. Applying this approach to the full Heusler alloy Fe2TiSn, Cr is introduced systematically at Ti site that conforms to the chemical formula [Formula: see text]Sn. Compositions so obtained have been investigated for its electronic, magnetic, and electrical transport properties with an aim to observe the half-metallic ferromagnetic ground state, anticipated theoretically for Fe2CrSn. Our experimental study using synchrotron X-ray diffraction reveals that only compositions with [Formula: see text] 0.25 yield phase pure L2[Formula: see text] cubic structures. The non-magnetic ground state of Fe2TiSn gets dramatically affected upon inclusion of Cr giving rise to a localized magnetic moment in the background of Ruderman-Kittel-Kasuya-Yosida (RKKY) correlations. The ferromagnetic interactions begin to dominate for x = 0.25 composition. Results of its resistivity and magnetoresistance (MR) measurement point towards a half-metallic ground state. The calculation of exchange coupling parameter, [Formula: see text], and orbital projected density of states that indicate a change in hybridization between 3d and 5p orbital, support the observations made from the study of local crystal structure made using the extended X-ray absorption fine structure spectroscopy. Our findings here highlight an interesting prospect of finding half-metallicity via band structure tailoring for wide application in spintronics devices.

8.
Opt Express ; 18(3): 2743-52, 2010 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-20174103

RESUMEN

A study of coupling between finite number of general-shaped grooves in electromagnetic plane-wave scattering problem is presented. The formulation for a single groove [1] is extended to two grooves. The importance of inclusion of coupling interaction between two grooves in scattering analysis is presented and its dependence on the grooves separation distance and the angle of incident of the electromagnetic field is demonstrated quantitatively. For larger angle of incident and smaller separation distance between grooves indicate larger discrepancy between between simulation results with and without inclusion of the coupling effects. Although the results presented here considers two grooves, the formulation can be extended to arbitrary number of grooves.

9.
Indian J Clin Biochem ; 25(2): 146-52, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23105901

RESUMEN

This study was conducted to evaluate whether microalbuminuria on admission and after 24 hrs of admission to intensive care unit (ICU) predicts outcome as well as the Acute Physiology and Chronic Health Evaluation (APACHE) II severity illness score, the current accepted method of doing so. The study was carried out in a 20 bed mixed medical-surgical ICU of a tertiary care hospital. Of 525 consecutive adult patients with ICU stay of more than 24 hrs, 238 were included for the study. Patients with pregnancy, menstruation, anuria, macroscopic hematuria, urinary tract infection, marked proteinuria due to renal and post-renal structural diseases, were excluded. Spot urine samples were collected on admission to ICU and 24 hrs thereafter. Urine albumincreatinine ratio (ACR) was measured on ICU admission (ACR1) and after 24 hrs (ACR2) and expressed in mg/g. Patient demographics were noted on admission. For disease severity scoring, APACHE II scores were calculated. Each patient was followed up throughout their ICU stay for a maximum of 28 days and the following outcome data were obtained: ICU length of stay and ICU mortality. Of the 238 patients, 196 survived while 42 patients died in the ICU. Non-survivors had a significantly higher median ACR2 [162.7 mg/g (IQR 69.5-344.3)] in comparison to the survivors who had a median ACR2 = 54.4 mg/g (IQR 19.0-129.1) (P< 0.0001). The median ACR1 [161.0 mg/g (IQR 29.0-369.3)] of non-survivors was higher than the median ACR1 [80.4 mg/g (IQR 35.1-167.6)] of survivors but failed to reach statistical significance (P= 0.0948). In a receiver operating characteristic curve (ROC) analysis, ACR2 emerged as the best indicator of mortality [(area under curve (AUC) of ACR2 = 0.71 > AUC (ACR1) =0.58 > AUC (ΔACR) =0.55] similar to the currently used APACHE II scores (AUC = 0.78) (P=0.3). At a cutoff of 101 mg/g, ACR2 had a sensitivity of 69%, specificity of 67%, positive predictive value of 31% and a negative predictive value of 91% for predicting mortality in the critically ill patients. Absence of significant microalbuminuria at 24 hrs of ICU admission may help to predict survival in the ICU.

10.
Int Immunol ; 20(12): 1489-505, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18931364

RESUMEN

The specific apoptotic role of T11TS has been well established in glioma animal models. T11TS specifically induces the glioma cells to die an apoptotic death via immune cross-talk with the two intracranial immune competent cells-microglia and the brain-infiltrating lymphocytes. To unearth the molecular cascades operative within the glioma cells and to some extent in the two interacting immunocytes, we had initiated studies where preliminary findings not only had indicated the involvement of death receptors but had also hinted to the involvement of other apoptotic regulators. Hence, to identify the molecular pathway of apoptosis involving other apoptotic regulators in the three cell types, the cells were studied for the intrinsic apoptotic death regulators that were engaged to maintain the mitochondrial membrane integrity. The proteins that were selected could be divided into three broad classes-the Bcl-2 family of proteins-Bid, Bax and Bcl-2; the guardian of the genome p53 and the proteins downstream of mitochondria-Apaf-1, cytochrome c, caspase-9 and caspase-3. Activated Bid as well as maximal p53 expression was observed in the first dose of T11TS thus dually activating the pro-apoptotic Bax in the first and second dose in the glioma cells. Concurrently, the pro-survival protein Bcl-2's expression level was very much down-regulated in the same two doses favoring the internal microenvironment to proceed for apoptosis. High expression of cytochrome c and Apaf-1 and the presence of active caspase-9 and active caspase-3 in all the T11TS-treated tumor-bearing groups further adjudicated apoptosis of the glioma cells with clear involvement of mitochondrial death pathway in the T11TS-treated animals. Even though expression of the apoptotic regulators remained more or less the same indicating the involvement of mitochondria in the two interacting immunocytes, the intensity of expression of these proteins was much lower than the tumor cells. The present work focuses on the mechanistic approach of how T11TS mediates apoptosis and hence is the first approach of its kind in the field of immunology where the immunotherapeutic molecule's mode of action has been worked out.


Asunto(s)
Apoptosis , Proteína Proapoptótica que Interacciona Mediante Dominios BH3/metabolismo , Caspasas/metabolismo , Glioma/metabolismo , Glioma/patología , Proteína X Asociada a bcl-2/metabolismo , Animales , Apoptosomas/metabolismo , Factor Apoptótico 1 Activador de Proteasas/metabolismo , Citocromos c/metabolismo , Activación Enzimática , Eritrocitos/metabolismo , Glioma/inducido químicamente , Linfocitos Infiltrantes de Tumor/patología , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/uso terapéutico , Microglía/patología , Mitocondrias/metabolismo , Compuestos de Nitrosourea , Ratas , Ovinos , Transducción de Señal
11.
Nanotechnology ; 20(20): 204007, 2009 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-19420655

RESUMEN

The local bonding and atomic environments in the Ni-catalyzed destabilized system LiBH4/MgH2 and the quaternary borohydride-amide phase Li3BN2H8, were studied by x-ray absorption spectroscopy. In both cases the Ni catalyst was introduced as NiCl2 and a qualitative comparison of the Ni K-edge near-edge structure suggests the Ni2+ is reduced to primarily Ni0 after ball milling. The extended fine structure of the Ni K edge indicates that the Ni is coordinated by approximately 3 boron atoms with an interatomic distance of approximately 2.1 A and approximately 11 Ni atoms in a split shell at around 2.5 and 2.8 A. These results, and the lack of long-range order, suggest that the Ni is present as a disordered nanocluster with a local structure similar to that of Ni3B. In the fully hydrogenated phase of LiBH4/MgH2 a small amount Mg2NiHx was also present. Surface calculations performed using density functional theory suggest that the lowest kinetic barrier for H2 chemisorption occurs on the Ni3B(100) surface.


Asunto(s)
Boratos/química , Hidrógeno/química , Compuestos de Litio/química , Modelos Químicos , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Níquel/química , Catálisis , Simulación por Computador , Cristalización/métodos , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de Superficie
12.
Math Biosci ; 217(2): 134-44, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19056405

RESUMEN

Epidemiology and ecology are traditionally treated as independent research areas, but there are many commonalities between these two fields. It is frequently observed in nature that the former has an encroachment into the later and changes the system dynamics significantly. In population ecology, in particular, the predator-prey interaction in presence of parasites can produce more complex dynamics including switching of stability, extinction and oscillations. On the other hand, harvesting practices may play a crucial role in a host-parasite system. Reasonable harvesting can remove a parasite, in principle, from their host. In this paper, we study theoretically the role of harvesting in a predator-prey-parasite system. Our study shows that, using impulsive harvesting effort as control parameter, it is not only possible to control the cyclic behavior of the system populations leading to the persistence of all species, but other desired stable equilibrium including disease-free can also be obtained.


Asunto(s)
Ecosistema , Métodos Epidemiológicos , Modelos Biológicos , Conducta Predatoria , Animales , Simulación por Computador , Peces/parasitología
13.
RSC Adv ; 9(68): 39649-39661, 2019 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-36105179

RESUMEN

The quantum-chemistry based force field (FF) developed for HMX by Smith and Bharadwaj (SB) [G. D. Smith and R. K. Bharadwaj, J. Phys. Chem. B, 1999, 103(18), 3570-3575] is transferred to another nitramine of different stoichiometry: hexanitrohexaazaisowurtzitane (CL-20 or HNIW). The modification of a single parameter alongside a very small number of add-ons related to carbon-carbon bonds, angles and dihedrals lead to two SB FF variants denoted SB-CL20 and SB-CL20 + CCNN. These flexible-molecule FFs should inherit the predictive capabilities of SB FF. For this purpose, we perform Molecular Dynamics simulations at ambient temperature and selected pressures. The modeled structures of the various CL-20 polymorphs are consistent with experimental data. Focusing on the ε-polymorph, we determine an equation of state which consolidates the general trend underpinned by most published results, and we confirm the increasing stiffness of the crystal under pressures up to 90 GPa. Moreover, we link some subtle pressure-induced changes of the elastic and structural properties to the flexibility and mobility of well-identified nitro groups. Finally, the simulations of the γ ↔ ζ phase transition suggest different multiple-step direct and reverse thermodynamic paths.

14.
J Phys Condens Matter ; 31(4): 045801, 2019 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-30543525

RESUMEN

With an aim to control the anti-site disorder between Fe and Ti atoms in the full Heusler alloy, Fe[Formula: see text]TiSn, we substitute a small percentage of Ti at Fe site to form the Fe[Formula: see text]Ti[Formula: see text]Sn ([Formula: see text]) series. Using the incident x-rays tuned to the Fe K-edge absorption energy, we record the high resolution synchrotron x-ray diffraction profiles and unambiguously show the reduction in anti-site disorder. In particular, the Fe-Ti anti-site disorder decreases up to an excess Ti content of 0.07; further increase of Ti content leads to disorder between Ti-Sn sites. Detailed characterization vis-á-vis the excess Ti content has been carried out in terms of its thermal and electrical transport, and magnetic properties. Signatures of strong spin fluctuation are seen in all the physical properties reported here. The much disputed high value of the Sommerfeld constant has been shown to be a resultant of such strong spin fluctuations, thus ruling out the long standing controversy of heavy fermionic nature of Fe[Formula: see text]TiSn. Magnetization and the Seebeck coefficient show clear dependence on the disorder. Both dc and ac magnetic measurements reveal the low temperature superparamagnetic nature of this system, comprising of large magnetic clusters [Formula: see text]3 nm in size.

15.
Cell Mol Immunol ; 5(2): 107-12, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18445340

RESUMEN

The concept of stem cells, their physiological existence, the intricate anatomical localization, the known and the unknown functions, and their exclusive utility for the purpose of regenerative medicine, are all now encompassed within an emergent question, 'how compatible these cells are immunologically?' Indeed, the medical aspects of stem cells are dependent on a large number of queries based on the basic properties of the cells. It has greatly been emphasized to probe into the basic research on stem cells before any successful therapeutic attempts are made. One of the intricate aspects of the adult stem cells is its immunological behavior in relation to the microenvironmental associates, the stromal cells in the presence of a suitable target.


Asunto(s)
Células Madre Adultas/inmunología , Células del Estroma/inmunología , Células Madre Adultas/citología , Proliferación Celular , Células del Estroma/citología
16.
Res Vet Sci ; 85(1): 120-4, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18378268

RESUMEN

Babesiosis is a common tick borne disease of dogs in tropical and subtropical regions of the world caused by different species of Babesia. The present study aimed to examine erythrocyte lipid peroxide and erythrocytic antioxidant levels in dogs with clinical babesiosis, caused by Babesia gibsoni, and impact of the disease on blood iron, zinc and copper levels. The study was conducted on 10 naturally occurring cases of canine babesiosis with the history of tick infestation, erratic pyrexia, and prolonged illness. Microscopic examination of Giemsa stained peripheral blood smears confirmed B. gibsoni infection in the erythrocytes. Six apparently healthy dogs of different age, sex and breeds, brought for either health checkup or vaccination were used for comparison. Levels of erythrocytic antioxidant enzymes were significantly (P<0.01) higher in sick dogs than those of cytologically negative dogs (catalase: 0.192+/-0.024 units/mg Hb vs 0.074+/-0.004 units/mg Hb; superoxide dismutase: 0.014+/-0.0009 units/mg Hb vs 0.006+/-0.0008 units/mg Hb and lipid peroxide: 6.01+/-0.30 nmol MDA/mg Hb vs 1.89+/-0.10 nmol MDA/mg Hb). The levels of blood micronutrients were significantly low in these dogs (iron: 89.87+/-8.12 microg/g vs 126.44+/-14.65 microg/g; zinc: 3.67+/-1.85 microg/g vs 5.62+/-1.83 microg/g and copper: 0.55+/-0.63 microg/g vs 0.65+/-0.04 microg/g). The study demonstrated oxidative damage in dogs naturally infected with B. gibsoni. Low level of blood iron, zinc and copper seems to have an additional role in the genesis of anaemia and oxidative stress.


Asunto(s)
Babesia/clasificación , Babesiosis/veterinaria , Enfermedades de los Perros/sangre , Eritrocitos/metabolismo , Peroxidación de Lípido/fisiología , Animales , Antioxidantes/metabolismo , Babesiosis/sangre , Cobre/sangre , Perros , Hierro/sangre , Zinc/sangre
17.
Acta Virol ; 52(4): 251-6, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19143482

RESUMEN

Leaf curl disease of kenaf (Hibiscus cannabinus L.) in India has been found to be associated with begomoviruses and betasatellites. Here, we report the molecular characterization and phylogenetic relationship of the nine isolates of betasatellites obtained from three geographical locations in India. The betasatellites coming from northern and eastern region of India shared 84.3% nucleotide sequence identity and formed two sub-clusters within the main cluster containing different isolates of Cotton leaf curl Multan betasatellite (CLCuMB) isolated in Indian subcontinent. Betasatellites coming from the southern part of India were identified as the isolates of Tomato leaf curl Joydebpur betasatellite and shared 45.2 and 44.9% sequences identity with their counterparts coming from the eastern and northern India, respectively. The present study represents the first report about the association of the leaf curl disease of kenaf with the betasatellites infecting both malvaceous and non-malvaceous crops in India.


Asunto(s)
Begomovirus/genética , ADN Satélite/genética , ADN Viral/genética , Variación Genética , Hibiscus/virología , Enfermedades de las Plantas/virología , Begomovirus/clasificación , Begomovirus/aislamiento & purificación , Datos de Secuencia Molecular , Filogenia
18.
J Phys Condens Matter ; 30(1): 015703, 2018 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-29211688

RESUMEN

The investigation of the magnetotransport properties on [Formula: see text] [Formula: see text]Sb x with 0 [Formula: see text] 0.6 are presented in this paper. The substitution of Sb in place of Sn decreases the anti-site disorder as evident from x-ray diffraction patterns as well as from transport properties measurement. The much-disputed upturn in low temperature electrical resistivity of [Formula: see text]TiSn has been demonstrated to be a result of weak localization induced by anti-site disorder. With increased Sb substitution (⩾25%) the metallic transport behavior of [Formula: see text]TiSn changes to semiconductor-like. At low temperature, carrier transport in such compositions occurs via the variable range hopping mechanism. Moreover, a systematic increase in the anomalous Hall voltage is observed with increasing Sb-content, attributable to a side jump or Berry phase curvature effect. Electrical resistivity in the entire temperature regime hints towards half metallicity of the system. Our ab initio electronic structure calculations using generalised gradient approximation formalism further supports the results of our magnetotransport study.

19.
Cell Mol Biol (Noisy-le-grand) ; 53(5): 53-62, 2007 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-17543233

RESUMEN

Free radicals and allied molecules are the potential threats for the cellular components when they are produced in excess amount and cause different pathophysiological disorders including aging. Contrary to their detrimental effects, these molecules, in the other hand, can be utilized by the Phagocytic cells to destroy the abnormal cells and cellular components. Generation of reactive oxygen species (ROS) and nitric oxide (NO) are used as important effector molecules by Phagocytic macrophage/microglia to eliminate neoplastic cells in glioma bearing rat model. The glycoprotein T11TS/SLFA-3, by binding with CD2 receptor of macrophage/microglia, induces the generation of these reactive species when applied in three consecutive doses in glioma bearing animals. The CR3 family receptor CD11b is also correlated with the Phagocytic activity of the cells. The 'controlled' and directed production of ROS and NO by phagocytes induce cell death signals to the glioma cells and resulted in phagocytic destruction and apoptosis. The death signals generated by the free radicals and associated molecules resulted in accumulation of p53 proteins in the glioma cells. This oxidative stress induced p53 protein accumulation in neoplastic cells direct them to die by apoptosis. Therefore, the same oxidative stress causing pathophysiological problems, are used here to destroy the glioma cells by the macrophage/microglia in the delicate CNS tissue.


Asunto(s)
Glioma/tratamiento farmacológico , Glicoproteínas/farmacología , Estallido Respiratorio , Animales , Antígeno CD11b/metabolismo , Muerte Celular/efectos de los fármacos , Glioma/metabolismo , Glioma/patología , Microglía/efectos de los fármacos , Microglía/metabolismo , Óxido Nítrico/metabolismo , Fagocitos/efectos de los fármacos , Fagocitos/metabolismo , Ratas , Especies Reactivas de Oxígeno/metabolismo , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/metabolismo
20.
J Nanosci Nanotechnol ; 7(12): 4402-11, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18283820

RESUMEN

Sol-gel synthesized SnO2 nanoparticles with an average size of 2.0 nm obtained at 373 K were gradually annealed to 673 K in air for 25 minutes. Sequentially taken transmission electron microscopy (TEM) images showed that particle agglomeration of these non-matrix SnO2 nanocrystals was a very slow process. The blue shifts of the band gap (approximately 2.3 eV) obtained from the optical absorbance spectra were matched with the theoretical results of the size related excitonic binding energies. These calculations also supported the observed slow grain growth. The depth sensitive hardness measurements of the thin films indicated hardness in the range of 5.03 GPa to 6.79 GPa. These undoped and non-matrix SnO2 nanoparticles were also investigated with the X-ray photoelectrons spectroscopy (XPS), atomic force microscope (AFM), X-ray diffraction spectroscopy (XRD), and ac impedance analyzer.

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