296 research outputs found
Dark Energy Density and IS (Israel-Stewart) Bulk Viscosity Model
We investigate the thermodynamics of a dark energy bulk viscosity model as a
cosmic fluid. In this regard, the two theories of Eckart and Israel-Stewart
(IS) are the basis of our work. Therefore, we first investigate the
thermodynamics of cosmic fluids in the dark energy bulk viscosity model and the
general relationships. Then, we express the thermodynamic relationships of
Eckart's theory. Due to the basic equations of Eckart's theory and Friedmann's
equations, we consider two states, one is (standard) and the other is
(non-standard). In the standard state, we define the pressure
, energy density , and bulk viscosity coefficient of the
cosmic fluid in terms of cosmic time and we obtain its relations. We also
mention that in this standard state, because of , the value of
is zero, so is not defined in this state. But in the non-standard case
the bulk viscosity coefficient is zero and only the
scale factor and pressure and energy density of the cosmic fluid is defined. We
also consider two states of constant and variable bulk viscosity coefficients
and obtain three Hubble constant parameters and scale factors in terms of
cosmic time, and energy density in terms of the scale factor. In the state of
variable bulk viscosity coefficient, we consider the viscosity coefficient as
the power-law from energy density , which is
and a constant. Following, we discuss the dissipative effects of cosmic fluids
and examine the effects of energy density for dark energy in the
Israel-Stewart(IS) theory. The results are comprehensively presented in two
tables (1) and (2).Comment: 28 pages, 11 figurs, 2 table
Cholinesterase inhibitory activity and structure elucidation of a new phytol derivative and a new cinnamic acid ester from Pycnanthus angolensis
AbstractThe leaves of Pycnanthus angolensis (Welw.) Warb., Myristicaceae, are used as memory enhancer and anti-ageing in Nigerian ethnomedicine. This study aimed at evaluating the cholinesterase inhibitory property as well as isolates the bioactive compounds from the plant. The acetylcholinesterase and butyrylcholinesterase inhibitory potentials of extracts, fractions, and isolated compounds were evaluated by colorimetric and TLC bioautographic assay techniques. The extract inhibited both enzymes with activity increasing with purification, ethyl acetate fraction being most active fraction at 65.66Β±1.06% and 49.38Β±1.66% against acetylcholinesterase and butyrylcholinesterase, respectively while the supernatant had 77.44Β±1.18 inhibition against acetylcholinesterase. Two new bioactive compounds, (2E, 18E)-3,7,11,15,18-pentamethylhenicosa-2,18-dien-1-ol (named eluptol) and [12-(4-hydroxy-3-methyl-oxo-cyclopenta-1,3-dien-1yl)-11-methyl-dodecyl](E)-3-(3,4-dimethylphenyl)prop-2-enoate (named omifoate A) were isolated from the plant with IC50 of 22.26ΞΌg/ml (AChE), 34.61ΞΌg/ml (BuChE) and 6.51ΞΌg/ml (AChE), 9.07ΞΌg/ml (BuChE) respectively. The results showed that the plant has cholinesterase inhibitory activity which might be responsible for its memory enhancing action, thus justifying its inclusion in traditional memory enhancing preparation
Prevalence of Integrons and Antibiotic Resistance Pattern in Acinetobacter baumannii Isolated from Clinical Samples of Iranian Patients: A Systematic Review and Meta-analysis
Background: Acinetobacter baumannii is an important opportunistic nosocomial pathogen. Class 1 integrons in A. baumannii plays a significant role in antibiotic resistance. Therefore, this study aimed to investigate the prevalence of integrons and antibiotic resistance pattern in A. baumannii isolated from clinical samples of Iranian patients. Methods: The Medical Subject Headings (MeSH) and the keywords with the help of Boolean operators ("AND" or "OR") were used alone or in combination to conduct the search. The searching process was conducted in the Web of Science, PubMed, Cochrane Library, Scopus, and Google Scholar databases and, also Iranian databases. The search was restricted to relevant English and Persian cross-sectional publications reporting the prevalence of Int1 in A. baumannii isolated from clinical samples from 1 January 2000 to 31 December 2018. The data were analyzed using Comprehensive Meta-Analysis software. Regarding the heterogeneity of studies, the random effects model was used. Cochrane Q and I2 tests was used to evaluate statistical heterogeneity between the studies. Results: Fifteen studies were included in the analysis. The combined prevalence of class 1 integrons in A. baumannii was 55.2 (95 CI: 44.8-65.1). The pooled prevalence of MDR A. baumannii isolates was 68.1. The highest resistance belonged to Aztreonam, followed by Ciprofloxacin, and Ceftazidime with a resistance rate of 97.6, 92.8, and 91.6, respectively. Tobramycin was reported as an effective antibiotic. Conclusions: The present study reported an alarmingly high prevalence of class 1 Integrons, and MDR isolates of A. baumannii recovered from clinical samples that should be considered. ΓΒ© 2019 Mehran G., et al
Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some selected Nigerian medicinal plants
COVID-19 in rheumatoid arthritis cases: an Iranian referral center experience
Coronavirus infections, known as COVID-19, can induce a fatal respiratory system infection and also affect other organs, such as the kidney and heart. The mortality rate has been estimated between 1 and 5 in previous reports; however, the mortality and morbidity can be higher in patients with the immune-deficiency condition. Rheumatoid arthritis (RA) is one of the most rheumatoid disorders, and it is important to report their clinical and paraclinical data when affected with COVID-19. Evidence about their laboratory and radiologic findings is limited. In this case series, 10 cases of chronic and approved rheumatoid arthritis (RA) affected by COVID-19 are presented. Only 40 had dry cough, but myalgia and weakness as the general first presentation of infections was reported in most cases (80). Gastrointestinal symptoms, including nausea/vomiting, diarrhea, anorexia, and abdominal pain, were reported in 50 of individuals. In blood cell count, 30 of cases had thrombocytopenia, and ESR in all cases was positive. Abnormal CRP and elevated LDH were seen in 90 of cases. In HRCT assessment, all cases had an abnormal parenchymal pattern, and 90 of cases presented the usual pattern of COVID-19 (bilateral multifocal GGO/consolidation). Although it is a limited report, these findings are helpful for comparison of clinical and paraclinical cases in RA cases with normal cases. ΓΒ© 2020, International League of Associations for Rheumatology (ILAR)
A role for core planar polarity proteins in cell contact-mediated orientation of planar cell division across the mammalian embryonic skin
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the articleβs Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the articleβs Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Β© The Author(s) 2017. Supplementary information accompanies this paper at doi:10.1038/s41598-017-01971-2.The question of how cell division orientation is determined is fundamentally important for understanding tissue and organ shape in both healthy or disease conditions. Here we provide evidence for cell contact-dependent orientation of planar cell division in the mammalian embryonic skin. We propose a model where the core planar polarity proteins Celsr1 and Frizzled-6 (Fz6) communicate the long axis orientation of interphase basal cells to neighbouring basal mitoses so that they align their horizontal division plane along the same axis. The underlying mechanism requires a direct, cell surface, planar polarised cue, which we posit depends upon variant post-translational forms of Celsr1 protein coupled to Fz6. Our hypothesis has parallels with contact-mediated division orientation in early C. elegans embryos suggesting functional conservation between the adhesion-GPCRs Celsr1 and Latrophilin-1. We propose that linking planar cell division plane with interphase neighbour long axis geometry reinforces axial bias in skin spreading around the mouse embryo body.Peer reviewe
Clinical effects of Garcinia kola in knee osteoarthritis
<p>Abstract</p> <p>Objectives</p> <p>Over the past years, there has been a growing number of knee osteoarthritis (KOA) patients who are not willing to comply with long-term non-steroidal anti-inflammatory drugs (NSAID) treatment and wish to use herbal anti- rheumatic medicine. This study assessed the clinical effects of <it>Garcinia kola </it>(GK) in KOA patients.</p> <p>Patients and methods</p> <p>Prospective randomized, placebo controlled, double blind, clinical trial approved by the institutional medical ethics review board and written informed consent obtained from each patient. All KOA patients presenting at the Obafemi Awolowo University Teaching Hospital complex were recruited into the study. The patients were grouped into four (A = Placebo, B = Naproxen, C = <it>Garcinia kola</it>, D = Celebrex). The drugs and placebo were given twice a day per oral route. Each dose consisted of 200 mg of <it>G. kola</it>, Naproxen (500 mg), Celebrex (200 mg) and Ascorbic acid (100 mg). The primary outcome measure over six weeks study period was the change in mean WOMAC pain visual analogue scales (VAS). Secondary outcome measures included the mean change in joint stiffness and physical function (mobility/walking).</p> <p>Results</p> <p>143 patients were recruited, 84 (58.7%, males β 24, females β 60) satisfied the selection criteria and completed the study. The effect of knee osteoarthritis bilateralism among the subjects was not significant on their outcome (p > 0.05). The change in the mean WOMAC pain VAS after six weeks of <it>G. kola </it>was significantly reduced compared to the placebo (p < 0.001). Multiple comparisons of the mean VAS pain change of <it>G. kola </it>group was not lowered significantly against the naproxen and celebrex groups (p > 0.05). The onset of <it>G. kola </it>symptomatic pain relief was faster than the placebo (p < 0.001). However, it was slower than the active comparators (p > 0.05). The duration of therapeutic effect of <it>Garcinia kola </it>was longer than the placebo (p > 0.001). <it>G. kola </it>period of effect was less than naproxen and celebrex (p < 0.001). <it>G. kola </it>subjects had improved mean change mobility/walking after six weeks better than the control group(p < 0.001). The mean change in mobility of the <it>G. kola </it>group when compared to the active comparators was not significantly better (p < 0.05). The mean change of knee joint stiffness (p < 0.001) and the change of mean WOMAC score (p < 0.001) were improved on <it>Garcinia kola </it>as compared to the placebo. The mid term outcome of eleven <it>Garcinia kola </it>subjects after cessation of use had a mean pain relief period of 17.27 +/- 5.15 days (range: 9β26 days). There was no significant cardiovascular, renal or drug induced adverse reaction to <it>Garcinia kola</it>.</p> <p>Conclusion</p> <p><it>Garcinia kola </it>appeared to have clinically significant analgesic/anti-inflammatory effects in knee osteoarthritis patients. <it>Garcinia kola </it>is a potential osteoarthritis disease activity modifier with good mid term outcome. Further studies are required for standardization of dosages and to determine long-term effects.</p
Synthesis and asymmetric hydrogenation of (3E)-1-benzyl-3-[(2-oxopyridin-1(2H)-yl)methylidene]piperidine-2,6-dione
The synthesis of (3E)-1-benzyl-3-[(2-oxopyridin-1(2H)-yl)methylidene]piperidine-2,6-dione 4 from N-benzylglutarimide was achieved in three steps. The asymmetric hydrogenation of 4 gave either the product of partial reduction (10) or full reduction (13), depending on the catalyst which was employed, in high ee in each case. Attempts at asymmetric transfer hydrogenation (ATH) of 4 resulted in formation of a racemic product
Order and Stochastic Dynamics in Drosophila Planar Cell Polarity
Cells in the wing blade of Drosophila melanogaster exhibit an in-plane polarization causing distal orientation of hairs. Establishment of the Planar Cell Polarity (PCP) involves intercellular interactions as well as a global orienting signal. Many of the genetic and molecular components underlying this process have been experimentally identified and a recently advanced system-level model has suggested that the observed mutant phenotypes can be understood in terms of intercellular interactions involving asymmetric localization of membrane bound proteins. Among key open questions in understanding the emergence of ordered polarization is the effect of stochasticity and the role of the global orienting signal. These issues relate closely to our understanding of ferromagnetism in physical systems. Here we pursue this analogy to understand the emergence of PCP order. To this end we develop a semi-phenomenological representation of the underlying molecular processes and define a βphase diagramβ of the model which provides a global view of the dependence of the phenotype on parameters. We show that the dynamics of PCP has two regimes: rapid growth in the amplitude of local polarization followed by a slower process of alignment which progresses from small to large scales. We discuss the response of the tissue to various types of orienting signals and show that global PCP order can be achieved with a weak orienting signal provided that it acts during the early phase of the process. Finally we define and discuss some of the experimental predictions of the model
Primary Cilia Are Not Required for Normal Canonical Wnt Signaling in the Mouse Embryo
Sonic hedgehog (Shh) signaling in the mouse requires the microtubule-based organelle, the primary cilium. The primary cilium is assembled and maintained through the process of intraflagellar transport (IFT) and the response to Shh is blocked in mouse mutants that lack proteins required for IFT. Although the phenotypes of mouse IFT mutants do not overlap with phenotypes of known Wnt pathway mutants, recent studies report data suggesting that the primary cilium modulates responses to Wnt signals.We therefore carried out a systematic analysis of canonical Wnt signaling in mutant embryos and cells that lack primary cilia because of loss of the anterograde IFT kinesin-II motor (Kif3a) or IFT complex B proteins (Ift172 or Ift88). We also analyzed mutant embryos with abnormal primary cilia due to defects in retrograde IFT (Dync2h1). The mouse IFT mutants express the canonical Wnt target Axin2 and activate a transgenic canonical Wnt reporter, BAT-gal, in the normal spatial pattern and to the same quantitative level as wild type littermates. Similarly, mouse embryonic fibroblasts (MEFs) derived from IFT mutants respond normally to added Wnt3a. The switch from canonical to non-canonical Wnt also appears normal in IFT mutant MEFs, as both wild-type and mutant cells do not activate the canonical Wnt reporter in the presence of both Wnt3a and Wnt5a.We conclude that loss of primary cilia or defects in retrograde IFT do not affect the response of the midgestation embryo or embryo-derived fibroblasts to Wnt ligands
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