140 research outputs found
Evolution of superconductivity in PrFe1-xCoxAsO with x = 0.0 to 1.0
We report the synthesis and physical property characterization of
PrFe1-xCoxAsO with x = 0.0 to 1.0. The studied samples are synthesized by solid
state reaction route via vacuum encapsulation method. The pristine compound
PrFeAsO does not show superconductivity, but rather exhibits a metallic step
like transition due to spin density wave ordering of Fe moments below 150 K,
followed by another upward step due to anomalous ordering of Pr moments at 12
K. Both the Fe-SDW and Pr-TN temperatures decrease monotonically with Co
substitution at Fe site. Superconductivity appears in a narrow range of x from
0.07 to 0.25 with maximum Tc at 11.12 K for x = 0.15. Samples, with x = 0.25
exhibit metallic behavior right from 300 K down to 2 K, without any Fe-SDW or
Pr-TN steps in resistivity. In fact, though Fe-SDW decreases monotonically, the
Pr-TN is disappeared even with x = 0.02. The magneto transport measurements
below 14 Tesla on superconducting polycrystalline Co doped PrFeAsO lead to
extrapolated values of the upper critical fields [Hc2(0)] of up to 60 Tesla.Comment: 15 pages Text+Fig
An Energy Constraint Approach to Improve Lifetime and Reduce Routing Overhead in Heterogeneous MANET
Heterogeneous Mobile Ad-hoc Networks (H-MANET) contain different configuration nodes, each of which communicates over a wireless channel and is capable of movement. Heterogeneous wireless networking has attracted lot of interest from consumers in the previous few years for its applications in mobile and personal communications. One of the main constraints in MANET is the high probability of failure due to energy-exhausted nodes. So if the path selected for communication has low battery life then the path breaks prematurely and the re-discovery phase starts, which costs more overhead in the network. Therefore, there is unequal consumption of node energy, which must be prevented. The energy expenditure of the nodes should be balanced in order to minimize path breakage. This can be done by finding the communication path that is the most energy-efficient among alternative disjoint paths. This approach reduces path breakage and routing overhead caused by nodes with low battery life dying in the communication path, thus increasing the network's lifetime
Pattern and management of penetrating and nonpenetrating thoracic injuries
Background: Chest trauma constitutes a major public health problem which includes the injuries to chest wall, pleura, tracheobronchial tree, lungs, diaphragm, oesophagus, heart and great vessels. It consist of more than ten percent of all traumas and twenty five percent of death due to trauma occurs because of chest injury. Chest trauma is increasing in frequency in urban hospitals. Penetrating and nonpenetrating thoracic injuries the most serious injuries leading to significant morbidity and mortality.Methods: This study was prospective observational study of 220 patients of thoracic trauma both penetrating and non-penetrating. These patients admitted in general surgical units from August 2017 to May 2018 of Pandit Bhagwat Dayal Sharma, PGIMS Rohtak Haryana India. The study was pertaining to both penetrating and non-penetrating chest trauma.Results: Out of 220 chest injury patients who were studied during the said period, Males were 203 and females 17 by a ratio of 12:1 and age ranged from lowest 18 years to 85 years of age. Majority of the patients (90.45%) sustained blunt injuries. RTA was the common mechanism of blunt injury affecting (50.45%) of patients. Multiple Rib fractures was the commonest type of chest injury (21.36%) followed by head injury (17.27%). Head injury was the commonest associated injury seen in our patients. Conclusions: Chest trauma resulting from road traffic accident remains a major mechanism of chest injury. The measures to decrease the trauma are, educating people about traffic rules and regulations and strictly implementing them is necessary to reduce incidence of chest injuries
Recent pattern of Co-infection amongst HIV seropositive individuals in tertiary care hospital, kolkata
<p>Abstract</p> <p>Background</p> <p>Opportunistic Infections (OIs) and co-infections are the major cause of deaths amongst HIV infected individuals and this mostly depends upon the risk factors, type of exposure and geographic region. The commonest types of infections reported are tuberculosis, chronic diarrhoea, oral candidiasis, herpes simplex virus-2, cytomegalovirus, hepatitis B virus and hepatitis C virus. Due to the scarcity of OIs data available from this region, we had designed a study to determine the frequency of different OIs amongst HIV seropositive patients.</p> <p>Methods</p> <p>Analysis of the different spectrum of OIs/Co-infections were carried out with 204 HIV sero-positive patients (142 males and 62 females) who visited the HIV/AIDS Apex Clinic in a tertiary care hospital from March 2006 to March 2009. The CD4+ count was estimated using FACS Calibur, the routine smear test, serology, nested RT-PCR and DNA sequencing were carried out to determine the different OIs.</p> <p>Results</p> <p>In this study, HIV seropositive patients were mostly from middle age group (31-40 yrs) with CD4+ counts in majority of symptomatic AIDS patients below 200 cells/mm<sup>3</sup>. The common co-infections/opportunistic infections were OC (53.43%), CD (47.05%), HSV-2 (36.76%), TB (35.29%), CMV (26.96%), HBV (15.19%) and HCV (7.35%). Dual infections, like HSV-2 & CMV (15.38%), HSV-2 & TB (14.61%), HSV-2 & oral candidiasis (24.61%) and CMV & oral candidiasis (14.61%) were significant in follow-up patients. Triple infections were also common e.g., TB, CD, OC infection occurring frequently in about 14.21% of the study population. Multiple infections like OC, TB, CD amongst the viral co-infected patients with HSV-2, HCV, CMV and HBV are also reported in this study. The genotyping analysis of the HCV co-infected HIV individuals shows that two belonged to HCV genotype 1 and 8 belonged to genotype 3.</p> <p>Conclusions</p> <p>A wide spectrum of OIs were observed amongst HIV-infected patients in the HIV/AIDS Apex Clinic. Oral candidiasis, CD, CMV and HSV-2, were the common OIs in those patients. This study aims to provide a clearer picture regarding infections occurring amongst HIV seropositive individuals so that the scientific findings could be translated into sustainable prevention programmes and improved public health policies.</p> <p>Trial registration</p> <p>None</p
Large parathyroid adenomas: Potential mechanisms to reconcile adenoma size and disease phenotype
Parathyroid adenomas weighing more than 3.5 g are reported variously as atypical , large or giant parathyroid adenomas. All such adenomas are rare variants accounting for no more than 1.5% of all parathyroid adenomas. Large parathyroid adenomas are often associated with more severe form of the disease, including osteitis fibrosa cystica (OFC) and share many biochemical, histological, and molecular features of both benign and malignant parathyroid neoplasms, and are considered a distinct clinical entity. However, the pathogenesis of oversized parathyroid adenomas and the often-associated skeletal phenotype remains unclear. We present 5 cases of primary hyperparathyroidism (PHPT) with OFC, an uncommon manifestation of contemporary PHPT, associated with larger parathyroid adenomas, seen in the Bone and Mineral Disorders Clinic of the Henry Ford Health in the last 30 years to illustrate the critical role of vitamin D nutrition in the pathogenesis of both the OFC and adenoma size. The estimated prevalence of OFC was very low 0.2%, 5 of the \u3e3000 surgically confirmed cases of PHPT seen during this time. The mean ± SD values were: age: 36.8 ± 22.1 years (4 of the 510 years of follow-up. Because OFC is a very rare in the West, but very common areas of endemic vitamin D deficiency, we also examined the relationship between vitamin D nutrition, as assessed by serum 25-hydroxyvitamin D level, and parathyroid adenoma weight as well as prevalence of OFC in two large secularly diverse cohorts of patients with PHPT (Detroit, USA and Chandigarh, India). Based on this relationship and the relative prevalence of OFC in these two large cohorts, we propose that vitamin D nutrition (and perhaps calcium nutrition) best explains both the adenoma size and prevalence of OFC
Analysis of genetic and epigenetic variation in in vitro propagated potato somatic hybrid by AFLP and MSAP marker
Background: Genetic and epigenetic changes (DNA methylation) were
examined in the tissue-culture propagated interspecific potato somatic
hybrids between dihaploid Solanum tuberosum and S. pinnatisectum .
Amplified fragment length polymorphism (AFLP) and methylation-sensitive
amplified polymorphism (MSAP) were applied to detect the genetic and
epigenetic changes, respectively in the somatic hybrids mother plants
(1st cycle) and their regenerants (30th cycles sub-cultured). Results:
To detect genetic changes, eight AFLP primer combinations yielded a
total of 329 scorable bands of which 49 bands were polymorphic in both
mother plants and regenerants. None of the scorable bands were observed
in term of loss of original band of mother plant or gain of novel band
in their regenerants. AFLP profiles and their cluster analysis based on
the Jaccard\u2019s similarity coefficient revealed 100% genetic
similarity among the mother plant and their regenerants. On the other
hand, to analyze epigenetic changes, eight MSAP primer pair
combinations detected a few DNA methylation patterns in the mother
plants (0 to 3.4%) and their regenerants (3.2 to 8.5%). Out of total
2320 MSAP sites in the mother plants, 2287 (98.6%) unmethylated, 21
(0.9%) fully methylated and 12 (0.5%) hemi-methylated, and out of total
2494 MSAP sites in their regenerants, 2357 (94.5%) unmethylated, 79
(3.1%) fully methylated and 58 (2.3%) hemi-methylated sites were
amplified. Conclusion: The study concluded that no genetic variations
were observed among the somatic hybrids mother plants and their
regenerants by eight AFLP markers. However, minimum epigenetic
variations among the samples were detected ranged from 0 to 3.4%
(mother plants) and 3.2 to 8.5% (regenerants) during the tissue culture
process
Phylogeography and Population Structure Analysis Reveal Diversity by Gene Flow and Mutation in Ustilago segetum (Pers.) Roussel tritici Causing Loose Smut of Wheat
Ustilago segetum (Pers.) Roussel tritici (UST) causes loose smut of wheat account for considerable grain yield losses globally. For effective management, knowledge of its genetic variability and population structure is a prerequisite. In this study, UST isolates sampled from four different wheat growing zones of India were analyzed using the second largest subunit of the RNA polymerase II (RPB2) and a set of sixteen neutral simple sequence repeats (SSRs) markers. Among the 112 UST isolates genotyped, 98 haplotypes were identified. All the isolates were categorized into two groups (K = 2), each consisting of isolates from different sampling sites, on the basis of unweighted paired-grouping method with arithmetic averages (UPGMA) and the Bayesian analysis of population structure. The positive and significant index of association (IA = 1.169) and standardized index of association (rBarD = 0.075) indicate population is of non-random mating type. Analysis of molecular variance showed that the highest variance component is among isolates (91%), with significantly low genetic differentiation variation among regions (8%) (Fst = 0.012). Recombination (Rm = 0) was not detected. The results showed that UST isolates have a clonal genetic structure with limited genetic differentiation and human arbitrated gene flow and mutations are the prime evolutionary processes determining its genetic structure. These findings will be helpful in devising management strategy especially for selection and breeding of resistant wheat cultivars
Signals of R-parity violating supersymmetry in neutrino scattering at muon storage rings
Neutrino oscillation signals at muon storage rings can be faked by
supersymmetric (SUSY) interactions in an R-parity violating scenario. We
investigate the -appearance signals for both long-baseline and near-site
experiments, and conclude that the latter is of great use in distinguishing
between oscillation and SUSY effects. On the other hand, SUSY can cause a
manifold increase in the event rate for wrong-sign muons at a long-baseline
setting, thereby providing us with signatures of new physics.Comment: 7 pages LaTeX, 4 ps figures, accepted for publication in Phys. Rev.
OsJAZ11 regulates phosphate starvation responses in rice
Main conclusion: OsJAZ11 regulates phosphate homeostasis by suppressing jasmonic acid signaling and biosynthesis in rice roots. Abstract: Jasmonic Acid (JA) is a key plant signaling molecule which negatively regulates growth processes including root elongation. JAZ (JASMONATE ZIM-DOMAIN) proteins function as transcriptional repressors of JA signaling. Therefore, targeting JA signaling by deploying JAZ repressors may enhance root length in crops. In this study, we overexpressed JAZ repressor OsJAZ11 in rice to alleviate the root growth inhibitory action of JA. OsJAZ11 is a low phosphate (Pi) responsive gene which is transcriptionally regulated by OsPHR2. We report that OsJAZ11 overexpression promoted primary and seminal root elongation which enhanced Pi foraging. Expression studies revealed that overexpression of OsJAZ11 also reduced Pi starvation response (PSR) under Pi limiting conditions. Moreover, OsJAZ11 overexpression also suppressed JA signaling and biosynthesis as compared to wild type (WT). We further demonstrated that the C-terminal region of OsJAZ11 was crucial for stimulating root elongation in overexpression lines. Rice transgenics overexpressing truncated OsJAZ11ΔC transgene (i.e., missing C-terminal region) exhibited reduced root length and Pi uptake. Interestingly, OsJAZ11 also regulates Pi homeostasis via physical interaction with a key Pi sensing protein, OsSPX1. Our study highlights the functional connections between JA and Pi signaling and reveals JAZ repressors as a promising candidate for improving low Pi tolerance of elite rice genotypes
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