1,014 research outputs found
Do all states undergo sudden death of entanglement at finite temperature?
In this paper we consider the decay of quantum entanglement, quantified by
the concurrence, of a pair of two-level systems each of which is interacting
with a reservoir at finite temperature T. For a broad class of initially
entangled states, we demonstrate that the system always becomes disentangled in
a finite time i.e."entanglement sudden death" (ESD) occurs. This class includes
all states which previously had been found to have long-lived entanglement in
zero temperature reservoirs. Our general result is illustrated by an example.Comment: 4 pages, 3 figure
Entrepreneurs - Turns Massive Challenges (Covid 19) In To Meaningful Change
An entrepreneur is a person who undertakes risk to make profit from an opportunity, than working as an ordinary employee. As we are experiencing the worldwide COVID-19 pandemic, Entrepreneurs have to face a new challenge: that it is not only a huge sanitary and health crisis affecting people in all over the world. Though the world is changing rapidly in to the different scenario and reality are not the same depending on where you are running your business today. This is also an unprecedented downturn on the global economy. This paper presents how an Entrepreneur turns massive complexity into meaningful change. Entrepreneurs must initiate the financial and operational challenges of COVID - 19 while rapidly addressing the needs of their people, customers and suppliers
FORMULATION AND EVALUATION OF LIQUISOLID COMPACTS OF LORNOXICAM
Objective: Objective of the present investigation was to enhance the solubility and dissolution rate of poorly water-soluble drug lornoxicam using liquisolid technique with comparative determination of in vitro release profile of liquisolid compacts and conventional formulation of lornoxicam.
Methods: Formulation was prepared by a liquisolid technique using different drug concentration in a liquid vehicle and different carrier/coating ratio. Prepared liquisolid compact was evaluated for Fourier transform infrared (FTIR) spectra analysis, differential scanning calorimetry (DSC), X-ray diffraction (P-XRD), scanning electron microscopy (SEM) and in vitro dissolution study.
Results: The result showed that liquisolid compacts of lornoxicam displayed significantly higher drug release rate as compared to pure drug and conventional tablet prepared. The results of both DSC and X-ray crystallography indicated loss of crystallinity of the drug upon formulated into the liquisolid compact.
Conclusion: Dissolution rate of the drug from liquisolid compacts was affected by changing the drug concentration and excipient ratio. The liquisolid technique appeared to be a promising approach for improving the dissolution of poorly soluble drug lornoxicam
Mentorship and the Professional Development of Culturally Responsive Evaluators in the American Evaluation Association's Graduate Education Diversity Internship (GEDI) Program
In this study, we used Q methodology to investigate perspectives on mentorship among alumni of the Graduate Education Diversity Internship (GEDI) program. We asked participants to think retrospectively and give their opinion on the most important characteristics a GEDI mentor should have, based on what they would have liked or needed when they participated in the GEDI program. Three different perspectives on mentoring emerged from participants. They show that mentoring is not unidimensional; that perceptions and expectations of mentoring are defined to a great extent by the professional needs, background, and expectation of the participants. We suggest that the program takes those needs and expectations into consideration and use them as criteria for selecting mentors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108671/1/ev20093.pd
Sensitivity of the synaptic membrane Na+/Ca2+ exchanger and the expressed NCX1 isoform to reactive oxygen species
AbstractTwo plasma membrane proteins, the Na+/Ca2+ exchanger (NCX) and the Ca2+-ATPase, are major regulators of free intraneuronal Ca2+ levels as they are responsible for extrusion of Ca2+ from the intracellular to the extracellular medium. Because disruption of cellular Ca2+ regulation plays a role in damage occurring under conditions of oxidative stress, studies were conducted to assess the sensitivity of the NCX to reactive oxygen species (ROS). Exchanger activity in brain synaptic plasma membranes and in transfected CHO-K1 cells was inhibited following brief exposure to the peroxyl radical generating azo initiator 2,2′-azobis(2-amidinopropane)dihydrochloride (AAPH) and to peroxynitrite. Incubation with hydrogen peroxide did not alter NCX activity, even at 800 μM concentration. In CHO-K1 cells transiently transfected with the NCX1 isoform of the exchanger, AAPH treatment decreased the maximal transport capacity (Vmax), whereas the Kact remained unchanged. Peroxynitrite led to an increase in Kact with no change in Vmax. Loss of activity following exposure to either AAPH or peroxynitrite was associated with the formation of high molecular weight aggregates of NCX, and AAPH also caused fragmentation of the exchanger protein. These findings suggest that the NCX is sensitive to biologically relevant ROS and could be involved in the loss of Ca2+ homeostasis observed under oxidative stress
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Loss of Foveal Cone Structure Precedes Loss of Visual Acuity in Patients With Rod-Cone Degeneration.
PurposeTo assess the relationship between cone spacing and visual acuity in eyes with rod-cone degeneration (RCD) followed longitudinally.MethodsHigh-resolution images of the retina were obtained using adaptive optics scanning laser ophthalmoscopy from 13 eyes of nine RCD patients and 13 eyes of eight healthy subjects at two sessions separated by 10 or more months (mean 765 days, range 311-1935 days). Cone spacing Z-score measured as close as possible (average <0.25°) to the preferred retinal locus was compared with visual acuity (letters read on the Early Treatment of Diabetic Retinopathy Study [ETDRS] chart and logMAR) and foveal sensitivity.ResultsCone spacing was significantly correlated with ETDRS letters read (ρ = -0.47, 95%CI -0.67 to -0.24), logMAR (ρ = 0.46, 95%CI 0.24 to 0.66), and foveal sensitivity (ρ = -0.30, 95%CI -0.52 to -0.018). There was a small but significant increase in mean cone spacing Z-score during follow-up of +0.97 (95%CI 0.57 to 1.4) in RCD patients, but not in healthy eyes, and there was no significant change in any measure of visual acuity.ConclusionsCone spacing was correlated with visual acuity and foveal sensitivity. In RCD patients, cone spacing increased during follow-up, while visual acuity did not change significantly. Cone spacing Z-score may be a more sensitive measure of cone loss at the fovea than visual acuity in patients with RCD
Cellulase stimulation during biodegradation of lignocellulosic residues at increased biomass loading
Microbial degradation of lignocellulosic biomass is primarily affected by the composition and structure of biomass, as well as enzyme activities that are influenced by the presence of in-process degradation products.
This study focuses on the latter, and demonstrates that cellulase activity of Neurospora discreta is stimulated in the presence of in-process soluble lignin degradation products. Two types of biomass - cocopeat and sugarcane bagasse, with contrasting lignin content and cellulose structure were tested at two biomass loadings each. At the higher biomass loading, cocopeat showed the highest amount of hydrolyzed cellulose and cellulase activity, despite its low cellulose content and recalcitrant cellulose structure. A strong positive correlation was revealed between the amount of in-process degraded lignin and cellulase activity, indicating a stimulatory effect on cellulase, which contradicts most previous literature. Furthermore, the causal relationship between the amount of degraded lignin and cellulase activity was established in a model system of commercial cellulase and standard soluble lignin.
This work could pave the way for using biomass loading as a process lever to enhance cellulose hydrolysis in microbial conversion of lignocellulosic biomass
Effects of Paraquat-induced Oxidative Stress on the Neuronal Plasma Membrane Ca2+-ATPase
Oxidative stress leads to the disruption of calcium homeostasis in brain neurons; however, the direct effects of oxidants on proteins that regulate intracellular calcium [Ca2+]i are not known. The calmodulin (CaM) -stimulated plasma membrane Ca2+-ATPase (PMCA) plays a critical role in regulating [Ca2+]i. Our previous in vitro studies showed that PMCA present in brain synaptic membranes is readily inactivated by a variety of reactive oxygen species (ROS). The present studies were conducted to determine the vulnerability of PMCA to ROS generated in neurons as would likely occur in vivo. Primary cortical neurons were exposed to paraquat (PQ), a redox cycling agent that generates intracellular ROS. Low concentrations of PQ (5-10 μM) increased PMCA basal activity by 2-fold but abolished its sensitivity to CaM. Higher concentrations (25-100 μM) inhibited both components of PMCA activity. Immunoblots showed the formation of high molecular weight PMCA aggregates. Additionally, PMCA showed evidence of proteolytic degradation. PMCA proteolysis was prevented by a calpain inhibitor, suggesting a role for calpain. Our findings suggest that PMCA is a sensitive target of oxidative stress in primary neurons. Inactivation of this Ca2+ transporter under prolonged oxidative stress could alter neuronal Ca2+ signaling
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