197 research outputs found
Information capacity analysis of fully correlated multi-level amplitude damping channels
The primary objective of quantum Shannon theory is to evaluate the capacity
of quantum channels. In spite of the existence of rigorous coding theorems that
quantify the transmission of information through quantum channels,
superadditivity effects limit our understanding of the channel capacities. In
this paper, we mainly focus on a family of channels known as multi-level
amplitude damping channels. We investigate some of the information capacities
of the simplest member of multi-level Amplitude Damping Channel, a qutrit
channel, in the presence of correlations between successive applications of the
channel. We find the upper bounds of the single-shot classical capacities and
calculate the quantum capacities associated with a specific class of maps after
investigating the degradability property of the channels. Additionally, the
quantum and classical capacities of the channels have been computed in
entanglement-assisted scenarios
Preservation and enhancement of quantum correlations under Stark effect
We analyze the dynamics of quantum correlations by obtaining the exact
expression of Bures distance entanglement, trace distance discord, and local
quantum uncertainty of two two-level atoms. Here, the atoms undergo two-photon
transitions mediated through an intermediate virtual state where each atom is
separately coupled to a dissipative reservoir at zero temperature in the
presence of the Stark shift effect. We have investigated the dynamics of this
atomic system for two different initial conditions of the environment. In the
first case, we have assumed the environment's state to be in ground state and
in the other case, we have assumed the state to be in first excited state. The
second initial condition is significant as it shows the role played by both the
Stark shift parameters in contrast to only one of the Stark shift parameters
for the first initial condition. Our results demonstrate that quantum
correlations can be sustained for an extended period in the presence of Stark
shift effect in the case of both Markovian and non-Markovian reservoirs. The
effect in the non-Markovian reservoir is more prominent than the Markovian
reservoir, even for a very small value of the Stark shift parameter. We observe
that among the correlation measures considered, only local quantum uncertainty
is accompanied by a sudden change phenomenon, i.e., an abrupt change in the
decay rate of a correlation measure. Our findings are significant as preserving
quantum correlations is one of the essential aspects in attaining optimum
performance in quantum information tasks
An Insight in to Paget’s Disease of Bone
Paget’s disease of bone (PDB) is a common disorder which may affect one or many bones. Although many patients are asymptomatic, a variety of symptoms and complications may occur. PDB is a focal disorder of bone turnover characterized by excessive bone resorption coupled with bone formation. PDB begins with a period of increased osteoclastic activity and bone resorption, followed by increased osteoblast production of woven bone that is poorly mineralized. In the final phase of the disease process, dense cortical and trabecular bone deposition predominates, but the bone is sclerotic and poorly organized and lacks the structural integrity and strength of normal bone. This article briefly reviews the etiopathogenesis, clinical radiographic and histological features of Paget’s disease.Keywords: Osteoclast, osteoprotegerin, receptor activator of NF‑kB, receptor activator of NF‑kB ligan
Prediction of outcome in adults with severe falciparum malaria: a new scoring system
BACKGROUND: Mortality of falciparum malaria is related to the presence of severe complications. However, no scoring system is available to predict outcome of these patients. The aim of this paper was to devise a simple and reliable malaria prognosis score (MPS) to predict the outcome of adults with severe malaria. METHODS: All slide-positive severe falciparum malaria patients admitted to Ispat General Hospital were studied. Eight clinical parameters that may potentially differentiate or influence the outcome were identified to predict recovery or death RESULTS: Of 248 severe malaria cases, 35 died. There were 212 adults (34 deaths) and 36 children (one death). The malaria score for adults was (MSA) = 1(severe anaemia) + 2 (acute renal failure) + 3(Respiratory distress) +4 (cerebral malaria). The MSA ranges from 0 to 10. The mortality was 2% for MSA 0 – 2; 10% for MSA 3–4, 40% for MSA 5–6 and 90% for MSA 7 or more. The sensitivity is 89.9% and positive predictive value is 94.1% when 5 is taken as the cut off value. CONCLUSION: MSA is a simple and sensitive predictor. It can be administered rapidly and repeatedly to prognosticate the outcome of severe malaria in adults. It can help the treating doctor to assess the patient as well as to communicate to the relatives of the patients about prognosis. The score needs revalidation in other geographical areas
Optimized Hydrophobic Interactions and Hydrogen Bonding at the Target-Ligand Interface Leads the Pathways of Drug-Designing
Weak intermolecular interactions such as hydrogen bonding and hydrophobic interactions are key players in stabilizing energetically-favored ligands, in an open conformational environment of protein structures. However, it is still poorly understood how the binding parameters associated with these interactions facilitate a drug-lead to recognize a specific target and improve drugs efficacy. To understand this, comprehensive analysis of hydrophobic interactions, hydrogen bonding and binding affinity have been analyzed at the interface of c-Src and c-Abl kinases and 4-amino substituted 1H-pyrazolo [3, 4-d] pyrimidine compounds.In-silico docking studies were performed, using Discovery Studio software modules LigandFit, CDOCKER and ZDOCK, to investigate the role of ligand binding affinity at the hydrophobic pocket of c-Src and c-Abl kinase. Hydrophobic and hydrogen bonding interactions of docked molecules were compared using LigPlot program. Furthermore, 3D-QSAR and MFA calculations were scrutinized to quantify the role of weak interactions in binding affinity and drug efficacy.The in-silico method has enabled us to reveal that a multi-targeted small molecule binds with low affinity to its respective targets. But its binding affinity can be altered by integrating the conformationally favored functional groups at the active site of the ligand-target interface. Docking studies of 4-amino-substituted molecules at the bioactive cascade of the c-Src and c-Abl have concluded that 3D structural folding at the protein-ligand groove is also a hallmark for molecular recognition of multi-targeted compounds and for predicting their biological activity. The results presented here demonstrate that hydrogen bonding and optimized hydrophobic interactions both stabilize the ligands at the target site, and help alter binding affinity and drug efficacy
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The effect of pond dyes on oviposition and survival in wild UK Culex mosquitoes
British Culex pipiens complex [Culex pipiens sensu lato) mosquito distribution, abundance, and potential for disease transmission are intimately linked to their environment. Pond and lake dyes that block light to restrict algal photosynthesis are a relatively new product assumed to be an environmentally friendly since they are based on food dyes. Their use in urban garden ponds raises questions linked to mosquito oviposition, since coloured water can be an attractant. Culex (mostly pipiens) is commonly found in UK gardens and is a potential vector of viruses including the West Nile Virus (WNV). Any factors that significantly change the distribution and population of Cx pipiens could impact future risks of disease transmission.
A gravid trap was used to catch female Cx pipiens mosquitoes for use in oviposition choice tests in laboratory and semi-field conditions. Two types of pond dye, blue and shadow (which looks slightly red), were tested for their impact on oviposition and survival of wild caught Cx pipiens. There were no significant differences in the number of egg batches laid when gravid mosquitoes were given a choice between either blue dye and clear water or shadow dye and clear water indicating that these dyes are not attractants. Larvae hatched from egg batches laid by wild-caught gravid females were used to measure survival to adulthood with or without dye, , in a habitat controlled to prevent further colonisation. The experiment was run twice, once in the summer and again in the autumn, whereas the dyes had no impact on emergence in the summer, there were highly significant reductions in emergence of adults in both dye treated habitats in the autumn.
Containers with or without shadow dye were placed outside to colonise naturally and were sampled weekly for larvae and pupae over a 6 month period through summer and autumn. There was a significant negative effect of shadow dye on pupal abundance in a three week period over the summer, but otherwise there was no effect. It is likely that population abundance and food was a more powerful factor for mosquito survival than the dye
Structure and microstructure evolution of Al-Mg-Si alloy processed by equal-channel angular pressing
An ultrafine grained Al–Mg–Si alloy was prepared by severe plastic deformation using the equal-channel angular pressing (ECAP) method. Samples were ECAPed through a die with an inner angle of F = 90° and outer arc of curvature of ¿ = 37° from 1 to 12 ECAP passes at room temperature following route Bc. To analyze the evolution of the microstructure at increasing ECAP passes, X-ray diffraction and electron backscatter diffraction analyses were carried out. The results revealed two distinct processing regimes, namely (i) from 1 to 5 passes, the microstructure evolved from elongated grains and sub-grains to a rather equiaxed array of ultrafine grains and (ii) from 5 to 12 passes where no change in the morphology and average grain size was noticed. In the overall behavior, the boundary misorientation angle and the fraction of high-angle boundaries increase rapidly up to 5 passes and at a lower rate from 5 to 12 passes. The crystallite size decreased down to about 45 nm with the increase in deformation. The influence of deformation on precipitate evolution in the Al–Mg–Si alloy was also studied by differential scanning calorimetry. A significant decrease in the peak temperature associated to the 50% of recrystallization was observed at increasing ECAP passes.Peer ReviewedPreprin
Binding Modes of Peptidomimetics Designed to Inhibit STAT3
STAT3 is a transcription factor that has been found to be constitutively activated in a number of human cancers.
Dimerization of STAT3 via its SH2 domain and the subsequent translocation of the dimer to the nucleus leads to
transcription of anti-apoptotic genes. Prevention of the dimerization is thus an attractive strategy for inhibiting the activity
of STAT3. Phosphotyrosine-based peptidomimetic inhibitors, which mimic pTyr-Xaa-Yaa-Gln motif and have strong to weak
binding affinities, have been previously investigated. It is well-known that structures of protein-inhibitor complexes are
important for understanding the binding interactions and designing stronger inhibitors. Experimental structures of
inhibitors bound to the SH2 domain of STAT3 are, however, unavailable. In this paper we describe a computational study
that combined molecular docking and molecular dynamics to model structures of 12 peptidomimetic inhibitors bound to
the SH2 domain of STAT3. A detailed analysis of the modeled structures was performed to evaluate the characteristics of the
binding interactions. We also estimated the binding affinities of the inhibitors by combining MMPB/GBSA-based energies
and entropic cost of binding. The estimated affinities correlate strongly with the experimentally obtained affinities.
Modeling results show binding modes that are consistent with limited previous modeling studies on binding interactions
involving the SH2 domain and phosphotyrosine(pTyr)-based inhibitors. We also discovered a stable novel binding mode
that involves deformation of two loops of the SH2 domain that subsequently bury the C-terminal end of one of the stronger
inhibitors. The novel binding mode could prove useful for developing more potent inhibitors aimed at preventing
dimerization of cancer target protein STAT3
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