First-principles study of possible shallow donors in ZnAl2O4 spinel

ZnAl2O4 (gahnite) is a ceramic which is considered a possible transparent conducting oxide (TCO) due to its wide band gap and transparency for UV. Defects play an important role in controlling the conductivity of a TCO material along with the dopant, which is the main source of conductivity in an otherwise insulating oxide. A comprehensive first-principles density functional theory study for point defects in ZnAl2O4 spinel is presented using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) to overcome the band gap problem. We have investigated the formation energies of intrinsic defects which include the Zn, Al, and O vacancy and the antisite defects: Zn at the Al site (Zn-Al) and Al at the Zn site (Al-Zn). The antisite defect Al-Zn has the lowest formation energy and acts as a shallow donor, indicating possible n-type conductivity in ZnAl2O4 spinel by Al doping

Awareness and use of internet services among first MBBS students

Background: Internet is used for various reasons in the field of medicine which include teaching, diagnosis, conduct of medical examination and research. It has become the world's biggest library where retrieval of scientific re-sources is only a mouse click away thus providing a wide range of information.Methods: A cross sectional study was carried out on of 142 first year MBBS students at PESIMSR, Kuppam, Andhra Pradesh, India. Data was collected with the help of a questionnaire.Results: The present study revealed that all students were using internet and felt it to be a useful tool. Most of the individuals felt that use of internet was time saving and utilized them for various activities.Conclusions: Though majority of the students have knowledge and awareness about the internet usage it is not being utilized properly as an educational tool. Attention should be paid to bring about interventional measures that can improve computer usage skills and access among students to reduce the occurrence of internet addiction behaviour.

Psycho-Social Behavioural Problems In Urban Primary School Children

Research Problem: What is the magnitude and correlates of psychosocial behavioural problems in primary school children of an urban area. Objectives:     i)    To  know  the  prevalence of psychosocial behavioural problems in primary school children of Agra Corporation.  ii) To see the impact of various biosocial factors on the prevalence of above problems. Design: Cross sectional study by questionnaire method and observation. Setting: Primary schools run by Agra Corporation. Participants: All the children studying in 7 primary schools selected from 108 schools run by Agra Corporation. Sample Size: 520 primary school children. Study Variables: Age, sex, socio-economic class and family size. Statistical Analysis: By percentage, Z - test and Chi-square test. Result: A majority of the study children (63.7%) were having some psychosocial behavioural problem or the other, the most common problem being educational difficulties (59.8%), The average number of problems per child was 2.9. The prevalence was highest in children from middle-sized families of low socio­economic class and in age group above 13 years

Submicron scale tissue multifractal anisotropy in polarized laser light scattering

The spatial fluctuations of the refractive index within biological tissues exhibit multifractal anisotropy, leaving its signature as a spectral linear diattenuation of scattered polarized light. The multifractal anisotropy has been quantitatively assessed by the processing of relevant Mueller matrix elements in the Fourier domain, utilizing the Born approximation and subsequent multifractal analysis. The differential scaling exponent and width of the singularity spectrum appear to be highly sensitive to the structural multifractal anisotropy at the micron/sub-micron length scales. An immediate practical use of these multifractal anisotropy parameters was explored for non-invasive screening of cervical precancerous alterations ex vivo, with the indication of a strong potential for clinical diagnostic purposes

Understanding the dietary relationship between extensive Noctiluca bloom outbreaks and Jellyfish swarms along the eastern Arabian Sea (West coast of India)

1389-1394The paper attempts to understand the interrelationship between recurring blooms of dinoflagellate, Noctiluca scintillans as well as increasing jellyfish swarms along the coastal waters of eastern Arabian Sea. The grazing of N. scintillans on diatoms in the productive waters with reduced competition pressure due to the opportunistic feeding of jellyfishes on zooplankton are described here. With the development of N. scintillans in the favourable environmental conditions, jellyfishes utilize this dinoflagellate as their food source and thrive in the coastal waters. Hence, trophic interaction between Noctiluca and jellyfishes leading to their proliferation in the coastal waters are delineated

Krüppel-like factor 5 is a crucial mediator of intestinal tumorigenesis in mice harboring combined ApcMin and KRASV12 mutations

<p>Abstract</p> <p>Background</p> <p>Both mutational inactivation of the adenomatous polyposis coli (<it>APC</it>) tumor suppressor gene and activation of the <it>KRAS </it>oncogene are implicated in the pathogenesis of colorectal cancer. Mice harboring a germline <it>Apc</it>^{<it>Min </it>}mutation or intestine-specific expression of the <it>KRAS</it>^<it>V</it>12gene have been developed. Both mouse strains develop spontaneous intestinal tumors, including adenoma and carcinoma, though at a different age. The zinc finger transcription factor Krüppel-like factor 5 (KLF5) has previously been shown to promote proliferation of intestinal epithelial cells and modulate intestinal tumorigenesis. Here we investigated the <it>in vivo </it>effect of <it>Klf5 </it>heterozygosity on the propensity of <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12double transgenic mice to develop intestinal tumors.</p> <p>Results</p> <p>At 12 weeks of age, <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice had three times as many intestinal tumors as <it>Apc</it>^{<it>Min </it>}mice. This increase in tumor number was reduced by 92% in triple transgenic <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. The reduction in tumor number in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice was also statistically significant compared to <it>Apc</it>^{<it>Min </it>}mice alone, with a 75% decrease. Compared with <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12, tumors from both <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-and <it>Apc</it>^{<it>Min </it>}mice were smaller. In addition, tumors from <it>Apc</it>^{<it>Min </it>}mice were more distally distributed in the intestine as contrasted by the more proximal distribution in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12and <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. Klf5 levels in the normal-appearing intestinal mucosa were higher in both <it>Apc</it>^{<it>Min </it>}and <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice but were attenuated in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. The levels of β-catenin, cyclin D1 and Ki-67 were also reduced in the normal-appearing intestinal mucosa of <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice when compared to <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice. Levels of pMek and pErk1/2 were elevated in the normal-appearing mucosa of <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice and modestly reduced in Apc^Min/<it>KRAS</it>^<it>V</it>12/<it>Klf5</it>^+/-mice. Tumor tissues displayed higher levels of both Klf5 and β-catenin, irrespective of the mouse genotype from which tumors were derived.</p> <p>Conclusions</p> <p>Results of the current study confirm the cumulative effect of <it>Apc </it>loss and oncogenic <it>KRAS </it>activation on intestinal tumorigenesis. The drastic reduction in tumor number and size due to <it>Klf5 </it>heterozygosity in <it>Apc</it>^<it>Min</it>/<it>KRAS</it>^<it>V</it>12mice indicate a critical function of KLF5 in modulating intestinal tumor initiation and progression.</p

Krüppel-like factor 5 is an important mediator for lipopolysaccharide-induced proinflammatory response in intestinal epithelial cells

Lipopolysaccharide (LPS) is a bacterially-derived endotoxin that elicits a strong proinflammatory response in intestinal epithelial cells. It is well established that LPS activates this response through NF-κB. In addition, LPS signals through the mitogen-activated protein kinase (MAPK) pathway. We previously demonstrated that the Krüppel-like factor 5 [KLF5; also known as intestine-enriched Krüppel-like factor (IKLF)] is activated by the MAPK. In the current study, we examined whether KLF5 mediates the signaling cascade elicited by LPS. Treatment of the intestinal epithelial cell line, IEC6, with LPS resulted in a dose- and time-dependent increase in KLF5 messenger RNA (mRNA) and protein levels. Concurrently, mRNA levels of the p50 and p65 subunits of NF-κB were increased by LPS treatment. Pretreatment with the MAPK inhibitor, U0126, or the LPS antagonist, polymyxin B, resulted in an attenuation of KLF5, p50 and p65 NF-κB subunit mRNA levels from LPS treatment. Importantly, suppression of KLF5 by small interfering RNA (siRNA) resulted in a reduction in p50 and p65 subunit mRNA levels and NF-κB DNA binding activity in response to LPS. LPS treatment also led to an increase in secretion of TNF-α and IL-6 from IEC6, both of which were reduced by siRNA inhibition of KLF5. In addition, intercellular adhesion molecule-1 (ICAM-1) levels were increased in LPS-treated IEC6 cells and this increase was associated with increased adhesion of Jurkat lymphocytes to IEC6. The induction of ICAM-1 expression and T cell adhesion to IEC6 by LPS were both abrogated by siRNA inhibition of KLF5. These results indicate that KLF5 is an important mediator for the proinflammatory response elicited by LPS in intestinal epithelial cells

A self-organized synthetic morphogenic liposome responds with shape changes to local light cues

Reconstituting artificial proto-cells capable of transducing extracellular signals into cytoskeletal changes can reveal fundamental principles of how non-equilibrium phenomena in cellular signal transduction affect morphogenesis. Here, we generated a Synthetic Morphogenic Membrane System (SynMMS) by encapsulating a dynamic microtubule (MT) aster and a light-inducible signaling system driven by GTP/ATP chemical potential into cell-sized liposomes. Responding to light cues in analogy to morphogens, this biomimetic design embodies basic principles of localized Rho-GTPase signal transduction that generate an intracellular MT-regulator signaling gradient. Light-induced signaling promotes membrane-deforming growth of MT-filaments by dynamically elevating the membrane-proximal tubulin concentration. The resulting membrane deformations enable recursive coupling of the MT-aster with the signaling system, which generates global self-organized morphologies that reorganize towards local external cues in dependence on prior shape. SynMMS thereby signifies a step towards bio-inspired engineering of self-organized cellular morphogenesis

Trophic status and nutrient regime of Cochin estuarine system, India

1395-1404The Cochin estuarine system (CES) being one among the world’s highly polluted and productive estuarine system was monitored to assess the trophic condition in view of the changing nutrient regime. The estuarine system was shallow, with mixo-oligo to mixo-mesohaline salinities (9.65 ± 6.99 ‰). The dissolved oxygen and the pH regime of the water column were 5.92 ± 1.13 mg L-1 and 7.42 ± 0.71, respectively. The study documents high dissolved inorganic nitrogen (28.95 ± 8.47 µmol L-1), dissolved inorganic carbon (1089.87 ± 362.36 µmol L-1), dissolved inorganic phosphate (7.76 ± 3.56 µmol L-1) and gross primary productivity (2.31 ± 1.14 gC m-3 day-1). However, explicitly augmented inorganic nutrients coupled with low dissolved oxygen, pH, and productivity patterns were observed in station 7. High dissolved inorganic carbon denoted net heterotrophic condition. Trophic index (TRIX units) was observed to be high compared to earlier reports, indicated eutrophicated condition with the highest value at station 1 (8.04 ± 0.28). Therefore, proper management interventions are required to restrict allochthonous nutrient loading to protect CES from further anthropogenic impacts and to mitigate the eutrophication process

Resonant inelastic X-ray scattering in a Mott insulator

We calculate the resonant inelastic X-ray scattering (RIXS) response in a Mott insulator which is described by the Falicov-Kimball model. The model can be solved exactly within the single site dynamical mean-field theory (DMFT) approximation and the calculated RIXS response is accurate up to a local background correction. We find that on resonance the RIXS response is greatly enhanced over various other non-resonant background effects and the response systematically evolves from a single peak structure, arising due to relaxation processes within the lower Hubbard band, to a two peak structure, arising due to relaxation processes within the upper Hubbard band as well as across the Mott gap into the lower Hubbard band, as we vary the incident photon frequency to access states from the bottom of the lower Hubbard band to the top of the upper Hubbard band. The charge transfer excitations are found to disperse monotonically outwards (as a function of transfered energy) as we go from the center of the Brillouin zone towards the zone corner. These correlation induced features have been observed by Hasan {\it et. al.} (Science {\bf 288}, 1811 (2000)) and many other experimentalists in RIXS measurements over various transition metal oxide compounds and are found to be robust and survive even for large Auger lifetime broadening effects. As a comparison, we also calculate the dynamic structure factor for this model, which is proportional to the nonresonant part of the response, and does not show these specific signatures.Comment: 14 pages, 14 figures, submitted to Physical Review