Class Transitions and Two Component Accretion Flow in GRS 1915+105

The light curve of the galactic micro-quasar GRS 1915+105 changes in at least thirteen different ways which are called classes. We present examples of the transitions from one class to another as observed by the IXAE instrument aboard the Indian Satellite IRS-P3. We find that the transitions are associated with changes in photon counts over a time-scale of only a few hours and they take place through unknown classes. Assuming that the transitions are caused by variation of the accretion rates, this implies that a significant fraction of the matter must be nearly freely falling in order to have such dramatic changes in such a short time.Comment: 9 pages, 6 figures, Astronomy and Astrophys. (in press

A critical review of anticancer properties of Withania somnifera (L.) Dunal with respect to the biochemical mechanisms of its phytochemical constituents

Cancer is a leading cause of mortality worldwide, the conventional chemotherapeutic drugs have been known for their toxicity and numerous side effects. A new approach to treat cancer involves phytochemical drugs. In the present review, anti-cancer activity of a class of steroidal lactones called withanolides obtained from Withania somnifera (L.) Dunal is discussed. The commonly studied bioactive compounds namely withaferin-A, withanoside IV, withanoside VI and withanolide-A among others obtained from methanolic and chloroform extract of the leaves and various alcoholic, aqueous and chloroform extract of roots have shown inhibition to various human cancer cell lines including skin, breast, colon, prostate, liver, ovary, cervical and lung. Prominent mechanisms of action include induction of apoptosis by NOS upregulation, ROS production and NBS2 or COX-2 inhibition; cytotoxicity by humoral and cell mediated immune response, activation of p53 and pRB and inhibition of various viral oncoproteins; cell cycle arrest by Cdc2 facilitated mitotic catastrophe, cyclin-D1 down-regulation and inhibition of transcription factors. Cancers are also controlled by inhibition of angiogenesis and metastasis of the tumor cells. In addition to anti-tumorogenic properties, W. somnifera also holds properties that make it a potential adjuvant in integrated cancer therapeutics and in enhancing the effectiveness of ongoing radiation therapy

High resolution X-ray spectrum of the accreting binary X-ray pulsar GX 1+4

We present here high resolution X-ray spectrum of the accreting binary X-ray pulsar GX 1+4 obtained with the High Energy Transmission Grating (HETG) instrument of the Chandra X-ray Observatory. This was supplemented by a simultaneous observation with the Proportional Counter Array (PCA) of the Rossi X-ray Timing Explorer (RXTE). During this observation, the source was in a somewhat low intensity state and the pulse profile with both Chandra and RXTE shows a narrow dip, characteristic of GX 1+4 in medium and low intensity states. The continuum X-ray spectrum obtained with the HETG and PCA can be fitted well with a high energy cutoff power-law model with line of sight absorption. Interestingly, we find that this low state is accompanied by a relatively small absorption column density. A 6.4 keV narrow emission line with an equivalent width of 70 eV is clearly detected in the HETG spectrum. The fluorescence iron line, or at least part of it is produced in the neutral or lowly ionized iron in the circumstellar material that also causes most of the line of sight absorption. In the HETG spectrum, we have found evidence for a weak (equivalent width ~30 eV) emission line at 6.95 keV. This line is identified as Ly_alpha emission line from hydrogen-like iron and the spectrum does not show emission lines from helium-like iron. We discuss various emission regions for the hydrogen-like iron emission line, like gas diffused into the Alfven sphere or an accretion curtain flowing from the inner accretion disk to the magnetic poles.Comment: 15 pages, 4 postscript figures, accepted for publication in The Astrophysical Journa

GRK6 regulates the hemostatic response to injury through its rate-limiting effects on GPCR signaling in platelets.

G protein-coupled receptors (GPCRs) mediate the majority of platelet activation in response to agonists. However, questions remain regarding the mechanisms that provide negative feedback toward activated GPCRs to limit platelet activation and thrombus formation. Here we provide the first evidence that GPCR kinase 6 (GRK6) serves this role in platelets, using GRK6-/- mice generated by CRISPR-Cas9 genome editing to examine the consequences of GRK6 knockout on GPCR-dependent signaling. Hemostatic thrombi formed in GRK6-/- mice are larger than in wild-type (WT) controls during the early stages of thrombus formation, with a rapid increase in platelet accumulation at the site of injury. GRK6-/- platelets have increased platelet activation, but in an agonist-selective manner. Responses to PAR4 agonist or adenosine 5\u27-diphosphate stimulation in GRK6-/- platelets are increased compared with WT littermates, whereas the response to thromboxane A2 (TxA2) is normal. Underlying these changes in GRK6-/- platelets is an increase in Ca2+ mobilization, Akt activation, and granule secretion. Furthermore, deletion of GRK6 in human MEG-01 cells causes an increase in Ca2+ response and PAR1 surface expression in response to thrombin. Finally, we show that human platelet activation in response to thrombin causes an increase in binding of GRK6 to PAR1, as well as an increase in the phosphorylation of PAR1. Deletion of GRK6 in MEG-01 cells causes a decrease in PAR1 phosphorylation. Taken together, these data show that GRK6 regulates the hemostatic response to injury through PAR- and P2Y12-mediated effects, helping to limit the rate of platelet activation during thrombus growth and prevent inappropriate platelet activation

Estimates of genetic parameters of fruit quality traits in teasle gourd (Momordica subangulata Blume. subsp. renigera)

The present investigation was carried out to assess genetic variability, heritability and genetic advance in five genotypes of teasle gourd. The experiment was laid out in a randomized block design with four replications. High phenotypic coefficients of variation were observed for all characters except ascorbic acid in excoarp, ascorbic acid in mesocarp, total soluble solids (TSS) in exocarp, b-carotene in exocarp, acidity in mesocarp, b-carotene in mesocarp, TSS in mesocarp, acidity in exocarp which showed high heritability coupled with high genetic advance indicating that these traits were gene control and simple phenotypic selection can be used for further improvement of these traits. Fruit weight, which showed the highest positive direct effect on fruit yield also showed positive correlation with β-carotene in exocarp. The most important fruit quality influencing traits from the study includes TSS content of exocarp and mesocarp since these traits character showed positive correlations with most important fruit quality characters.Keywords: Teasle gourd, clones, variability, heritability, genetic advance, correlation coefficientAfrican Journal of Biotechnology, Vol. 13(2), pp. 257-264, 8 January, 201

Length-weight relationship of selected commercially important marine fishes from east coast of India

The paper deals with length-weight relationship (LWR) of selected commercially important marine fishes from the east-coast of India. Samples were collected fortnightly from experimental fishing using trawl operated at depth up to 70 M off Vishakhapatnam coast on the east-coast of India during 2015-17. Measurements of total length (TL) (nearest to 0.1 cm) and body weight (nearest to 0.1 g) of individual fish were taken. The LWR showed good fit with r2 values ranging from 0.975 for Lepturacanthus savala Cuvier, 1829 to 0.999 for Upeneus vittatus Forsskål, 1775. The ‘b’ values ranged from 2.618 for Photopectoralis bindus Valenciennes, 1835 to 3.186 for L. savala Cuvier, 1829

Formulation and evaluation of poly (L-lactide-co-ε-caprolactone) loaded gliclazide biodegradable nanoparticles as a control release carrier

A biodegradable nanoparticle has been used frequently as drug delivery carrier due to its better encapsulation capacity, sustained/ control release property and less toxicity. Gliclazide (GLZ) is a second generation of hypoglycemic sulfonylurea and acts selectively on pancreatic ß cell to control diabetes mellitus. The objective of this study was to produce controlled release nanoparticles of Gliclazide using poly (L-lactide-co-ε-caprolactone) (PLCL). The method was optimized using design of experiments by employing a 3-factor, 3-level Design Expert (version 8.0.7.1) Statistical Design Software and was subjected to various characterization studies including Field Emission Scanning Electron Microscopy (FE-SEM), X-ray diffraction (XRD), Encapsulation efficiency (%EE), Particle Size Distribution (PSD), etc. Formulated nanoparticles were also subjected to Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) for studying interaction between drug and polymer and the effect of lyophilization (Freeze Drying) on developed nanoparticles.  The release profiles and encapsulation efficiencies are depended on the concentration of PLCL. These data demonstrated the efficacy of the biodegradable polymeric nanoparticles in controlling the gliclazide drug release profile as novel drug delivery system

Impact of Algorithmic Bias on Hospital Risk Stratification Scores Among Insurance Recipients

Introduction: Although medical schools are implementing programs to promote student scholarship, few programs exist to informally promote inter-student collaboration. Considering many medical students are early in the process of deciding what they want to spend their lives pursuing, and high levels of social connection and engagement may reduce burnout, we sought to evaluate medical students’ attitudes about inter-student collaboration. Methods: Approximately 1000 medical students in all classes at Sidney Kimmel Medical College (SKMC) were invited to complete a questionnaire. Data collection remains active. Survey questions included a rank order choice on how respondents would use a tool to learn about their classmates and a Likert scale measuring respondents’ attitudes about collaboration. We secondarily investigated the number of SKMC students for whom the responding student was aware of their background. Results: 166 students have responded to the survey; 24% were first year students, 32% were second year students, 23% were third year students, and 21% were fourth year students. 77.1% of respondents agreed that they had experience they would share with classmates if the opportunity was available and 78.8% agreed that they would engage a classmate who had knowledge in a topic the respondent wanted to explore. Students ranked “Hobbies” and “Community involvement” as the areas they most wanted to learn about their classmates. On average, respondents were aware of the backgrounds of 10 students in their class (IQR = 3.5 - 20) and 2 in other classes (IQR = 0 - 5). Discussion: Our results suggest that medical students at SKMC only know a small proportion of other students at SKMC. Students are eager to share their backgrounds and reach out to their peers to learn more about their hobbies and community involvement. Knowledge gained by this study will help us develop a tool that augments student connectivity in medical school