42 research outputs found
Statistical Significance of spectral lag transition in GRB 160625B
Recently Wei et al (arXiv:1612.09425) have found evidence for a transition
from positive time lags to negative time lags in the spectral lag data of GRB
160625B. They have fit these observed lags to a sum of two components: an
assumed functional form for intrinsic time lag due to astrophysical mechanisms
and an energy-dependent speed of light due to quadratic and linear Loren tz
invariance violation (LIV) models. Here, we examine the statistical
significance of the evidence for a transition to nega tive time lags. Such a
transition, even if present in GRB 160625B, cannot be due to an energy
dependent speed of light as th is would contradict previous limits by some 3-4
orders of magnitude, and must therefore be of intrinsic astrophysical origin .
We use three different model comparison techniques: a frequentist test and two
information based criteria (AIC and BIC). From the frequentist model comparison
test, we find that the evidence for transition in the spectral lag data is
favored at and for the linear and quadratic models
respectively. We find that AIC and BIC have values 10
for the spectral lag transition that was motivated as being due to quadratic
Lorentz invariance vio lating model pointing to "decisive evidence". We note
however that none of the three models (including the model of intr insic
astrophysical emission) provide a good fit to the data.Comment: 6 pages, 1 figur
Statistical Significance of Lorentz invariance violation from GRB 160625B
Recently Wei et al (arXiv:1612.09425) have found evidence for a transition from positive time lags to negative time lags in the spectral lag data of GRB 160625B. They have fit these observed lags to a sum of two components: an intrinsic time lag due to astrophysical mechanisms and an energy-dependent speed of light due to violation of Lorentz invariance, which could be a signature of quantum gravity. Here, we examine the statistical significance of the evidence for this claim using the same data by comparing it against the null hypothesis, viz. the time-lags are induced only by intrinsic delays. We use three different model comparison techniques: a frequentist test and two information based criteria (AIC and BIC). From the frequentist model comparison test, we find that evidence for Lorentz violation is favoured at 3.05σ and 3.74σ for linear and quadratic models respectively and do not cross the 5σ discovery threshold. We find that ΔAIC and ΔBIC have values ≳ 10 for the quadratic Lorentz violating model pointing to "decisive evidence" against Lorentz invariance violation compared to only astrophysically induced intrinsic emission. Another concern however is that none of the three models (including the null hypothesis) provide a good fit to the data, which implies that there is additional physics or systematic errors, which are not accounted for while fitting the data to these models
Garcinol loaded vitamin E TPGS emulsified PLGA nanoparticles: preparation, physicochemical characterization, in vitro and in vivo studies
Garcinol (GAR) is a naturally occurring polyisoprenylated phenolic compound. It has been recently
investigated for its biological activities such as antioxidant, anti-inflammatory, anti ulcer, and
antiproliferative effect on a wide range of human cancer cell lines. Though the outcomes are very
promising, its extreme insolubility in water remains the main obstacle for its clinical application. Herein
we report the formulation of GAR entrapped PLGA nanoparticles by nanoprecipitation method using
vitamin E TPGS as an emulsifier. The nanoparticles were characterized for size, surface morphology,
surface charge, encapsulation efficiency and in vitro drug release kinetics. The MTT assay depicted a
high amount of cytotoxicity of GAR-NPs in B16F10, HepG2 and KB cells. A considerable amount of cell
apoptosis was observed in B16f10 and KB cell lines. In vivo cellular uptake of fluorescent NPs on B16F10
cells was also investigated. Finally the GAR loaded NPs were radiolabeled with technetium-99m with
>95% labeling efficiency and administered to B16F10 melanoma tumor bearing mice to investigate the
in vivo deposition at the tumor site by biodistribution and scintigraphic imaging study. In vitro cellular
uptake studies and biological evaluation confirm the efficacy of the formulation for cancer treatmen
Role of Bcr1-Activated Genes Hwp1 and Hyr1 in Candida Albicans Oral Mucosal Biofilms and Neutrophil Evasion
Candida albicans triggers recurrent infections of the oropharyngeal mucosa that result from biofilm growth. Prior studies have indicated that the transcription factor Bcr1 regulates biofilm formation in a catheter model, both in vitro and in vivo. We thus hypothesized that Bcr1 plays similar roles in the formation of oral mucosal biofilms and tested this hypothesis in a mouse model of oral infection. We found that a bcr1/bcr1 mutant did not form significant biofilm on the tongues of immunocompromised mice, in contrast to reference and reconstituted strains that formed pseudomembranes covering most of the tongue dorsal surface. Overexpression of HWP1, which specifies an epithelial adhesin that is under the transcriptional control of Bcr1, partly but significantly rescued the bcr1/bcr1 biofilm phenotype in vivo. Since HWP1 overexpression only partly reversed the biofilm phenotype, we investigated whether additional mechanisms, besides adhesin down-regulation, were responsible for the reduced virulence of this mutant. We discovered that the bcr1/bcr1 mutant was more susceptible to damage by human leukocytes when grown on plastic or on the surface of a human oral mucosa tissue analogue. Overexpression of HYR1, but not HWP1, significantly rescued this phenotype. Furthermore a hyr1/hyr1 mutant had significantly attenuated virulence in the mouse oral biofilm model of infection. These discoveries show that Bcr1 is critical for mucosal biofilm infection via regulation of epithelial cell adhesin and neutrophil function
Zap1 Control of Cell-Cell Signaling in \u3ci\u3eCandida albicans\u3c/i\u3e Biofilms
Biofilms of Candida albicans include both yeast cells and hyphae. Prior studies indicated that a zap1/ mutant, defective in zinc regulator Zap1, has increased accumulation of yeast cells in biofilms. This altered yeast-hypha balance may arise from internal regulatory alterations or from an effect on the production of diffusible quorum-sensing (QS) molecules. Here, we develop biosensor reporter strains that express yeastspecific YWP1-RFP or hypha-specific HWP1-RFP, along with a constitutive TDH3-GFP normalization standard. Seeding these biosensor strains into biofilms allows a biological activity assay of the surrounding biofilm milieu. A zap1/ biofilm induces the yeast-specific YWP1-RFP reporter in a wild-type biosensor strain, as determined by both quantitative reverse transcription-PCR (qRT-PCR) gene expression measurements and confocal microscopy. Remediation of the zap1/ zinc uptake defect through zinc transporter gene ZRT2 overexpression reverses induction of the yeast-specific YWP1-RFP reporter. Gas chromatography-mass spectrometry (GC-MS) measurements of known organic QS molecules show that the zap1/ mutant accumulates significantly less farnesol than wild-type or complemented strains and that ZRT2 overexpression does not affect farnesol accumulation. Farnesol is a well-characterized inhibitor of hypha formation; hence, a reduction in farnesol levels in zap1/ biofilms is unexpected. Our findings argue that a Zap1- and zinc-dependent signal affects the yeast-hypha balance and that it is operative in the low-farnesol environment of the zap1/ biofilm. In addition, our results indicate that Zap1 is a positive regulator of farnesol accumulation
CURATION AND MANAGEMENT OF CULTURAL HERITAGE THROUGH LIBRARIES
Libraries, museums and archives hold valuable collections in a variety of media, presenting a vast
body of knowledge rooted in the history of human civilisation. These form the repository of the
wisdom of great works by thinkers of past and the present. The holdings of these institutions are
priceless heritage of the mankind as they preserve documents, ideas, and the oral and written
records. To value the cultural heritage and to care for it as a treasure bequeathed to us by our
ancestors is the major responsibility of libraries. The past records constitute a natural resource
and are indispensable to the present generation as well as to the generations to come. Libraries
preserve the documentary heritage resources for which they are primarily responsible. Any loss of
such materials is simply irreplaceable. Therefore, preserving this intellectual, cultural heritage
becomes not only the academic commitment but also the moral responsibility of the
librarians/information scientists, who are in charge of these repositories.
The high quality of the papers and the discussion represent the thinking and experience of experts
in their particular fields. The contributed papers also relate to the methodology used in libraries
in Asia to provide access to manuscripts and cultural heritage. The volume discusses best practices
in Knowledge preservation and how to collaborate and preserve the culture. The book also deals with
manuscript and archives issues in the digital era.
The approach of this book is concise, comprehensively, covering all major aspects of preservation
and conservation through libraries. The readership of the book is not just limited to library and
information science professionals, but also for those involved in conservation, preservation,
restoration or other related disciplines. The book will be useful for librarians, archivists and
conservators.
We thank the Sunan Kalijaga University, Special Libraries Association- Asian Chapter for their
trust and their constant support, all the contributors for their submissions, the members of the Local
and International Committee for their reviewing effort for making this publication possible
Biotechnology-based pharmaceutical products
Biotechnology-based pharmaceutical products as an essential portion of the marketed therapeutic agents are continuously evolving due to the increased number of approved products as well as products entering clinical trials. Biotechnology involves the use of a living organism or their products for human use including medical purposes. Production of therapeutic agents through biotechnology is a complex multistep process that requires careful considerations in various aspects. Therefore it is essential to understand the differences between biotechnology-based drugs and conventional drugs. Currently, different classes of therapeutic agents are produced via biotechnology, such as antibiotics, enzymes, vaccines, and monoclonal antibodies. In this chapter, the general production process of biotechnology-based pharmaceutical products is discussed along with their pharmacokinetic properties with particular emphasis on the common problems associated with these products. Finally, biotechnology-based therapeutic approaches such as gene therapy and pharmacogenomics are also briefly discussed