Body water conservation through selective brain cooling by the carotid rete: a physiological feature for surviving climate change?

Some mammals have the ability to lower their hypothalamic temperature below that of carotid arterial blood temperature, a process termed selective brain cooling. Although the requisite anatomical structure that facilitates this physiological process, the carotid rete, is present in members of the Cetartiodactyla, Felidae and Canidae, the carotid rete is particularly well developed in the artiodactyls, e.g. antelopes, cattle, sheep and goats. First described in the domestic cat, the seemingly obvious function initially attributed to selective brain cooling was that of protecting the brain from thermal damage. However, hyperthermia is not a prerequisite for selective brain cooling, and selective brain cooling can be exhibited at all times of the day, even when carotid arterial blood temperature is relatively low. More recently, it has been shown that selective brain cooling functions primarily as a water-conservation mechanism, allowing artiodactyls to save more than half of their daily water requirements. Here, we argue that the evolutionary success of the artiodactyls may, in part, be attributed to the evolution of the carotid rete and the resulting ability to conserve body water during past environmental conditions, and we suggest that this group of mammals may therefore have a selective advantage in the hotter and drier conditions associated with current anthropogenic climate change. A better understanding of how selective brain cooling provides physiological plasticity to mammals in changing environments will improve our ability to predict their responses and to implement appropriate conservation measures.EM201

A Study on Drug-Drug Interaction of Esomeprazole and Anti-Diabetic Drugs

Drug–drug interaction between esomeprazole at therapeutic and higher doses and sulfonylureas was studied. Sulfonylureas (tolbutamide 40 mg/kg and glibenclamide 40 µg/kg) were administered and the time to onset of hypoglycemia, the duration of the hypoglycemia, and the peak hypoglycemia were determined. Esomeprazole (1.8 mg/kg, 3.6 mg/kg, and 30 mg/kg) was administered for 8 days and its influence on sulfonylurea-induced hypoglycemia was studied. Therapeutic doses of esomeprazole, i.e., 1.8 mg/kg and 3.6 mg/kg dose did not influence the hypoglycemia induced by sulfonylureas. However, a higher dose, i.e., 30 mg/kg, did significantly enhance the duration of hypoglycemia and the peak hypolgycemia. Esomeprazole (30 mg/kg) by itself did not reduce the blood glucose levels; therefore, a pharmacodynamic type of drug interaction can be ruled out. Similarly, a pharmacokinetic type of drug interaction may be ruled out at therapeutic doses. The CYP isoenzyme system involved in the metabolism of sulfonylureas are not very sensitive to esomeprazole and the dose and frequency of administration of sulfonylurea need not be readjusted when they are used concomitantly with esomeprazole (at therapeutic doses)

The quadratic spinor Lagrangian is equivalent to the teleparallel theory

The quadratic spinor Lagrangian is shown to be equivalent to the teleparallel / tetrad representation of Einstein's theory. An important consequence is that the energy-momentum density obtained from this quadratic spinor Lagrangian is essentially the same as the ``tensor'' proposed by Moller in 1961.Comment: 10 pages, RevTe

Metamagnetic Quantum Criticality in Sr3Ru2O7

We consider the metamagnetic transition in the bilayer ruthenate, ${\rm Sr_3Ru_2O_7}$, and use this to motivate a renormalization group treatment of a zero-temperature quantum-critical end-point. We summarize the results of mean field theory and give a pedagogical derivation of the renormalization-group equations. These are then solved to yield numerical results for the susceptibility, the specific heat and the resistivity exponent which can be compared with measured data on ${\rm Sr_3Ru_2O_7}$ to provide a powerful test for the standard framework of metallic quantum criticality. The observed approach to the critical point is well-described by our theory explaining a number of unusual features of experimental data. The puzzling behaviour very near to the critical point itself, though, is not accounted for by this, or any other theory with a Fermi surface

Study of a Depolarizing Resonance at the IUCF Cooler Ring

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Five-Year Wilkinson Microwave Anisotropy Probe (WMAP1) Observations: Galactic Foreground Emission

We present a new estimate of foreground emission in the WMAP data, using a Markov chain Monte Carlo (MCMC) method. The new technique delivers maps of each foreground component for a variety of foreground models, error estimates of the uncertainty of each foreground component, and provides an overall goodness-of-fit measurement. The resulting foreground maps are in broad agreement with those from previous techniques used both within the collaboration and by other authors. We find that for WMAP data, a simple model with power-law synchrotron, free-free, and thermal dust components fits 90% of the sky with a reduced X(sup 2) (sub v) of 1.14. However, the model does not work well inside the Galactic plane. The addition of either synchrotron steepening or a modified spinning dust model improves the fit. This component may account for up to 14% of the total flux at Ka-band (33 GHz). We find no evidence for foreground contamination of the CMB temperature map in the 85% of the sky used for cosmological analysis

Sample-to-sample torque fluctuations in a system of coaxial randomly charged surfaces

Polarizable randomly charged dielectric objects have been recently shown to exhibit long-range lateral and normal interaction forces even when they are effectively net neutral. These forces stem from an interplay between the quenched statistics of random charges and the induced dielectric image charges. This type of interaction has recently been evoked to interpret measurements of Casimir forces in vacuo, where a precise analysis of such disorder-induced effects appears to be necessary. Here we consider the torque acting on a randomly charged dielectric surface (or a sphere) mounted on a central axle next to another randomly charged surface and show that although the resultant mean torque is zero, its sample-to-sample fluctuation exhibits a long-range behavior with the separation distance between the juxtaposed surfaces and that, in particular, its root-mean-square value scales with the total area of the surfaces. Therefore, the disorder-induced torque between two randomly charged surfaces is expected to be much more pronounced than the disorder-induced lateral force and may provide an effective way to determine possible disorder effects in experiments, in a manner that is independent of the usual normal force measurement.Comment: 7 pages, 3 fig

Synthesis, physicochemical characterization, toxicity and efficacy of a PEG conjugate and a hybrid PEG conjugate nanoparticle formulation of the antibiotic moxifloxacin

Antibiotic resistance is increasing at such an alarming rate that it is now one of the greatest global health challenges. Undesirable toxic side-effects of the drugs lead to high rates of non-completion of treatment regimens which in turn leads to the development of drug resistance. We report on the development of delivery systems that enable antibiotics to be toxic against bacterial cells while sparing human cells. The broad-spectrum fluoroquinolone antibiotic moxifloxacin (Mox) was successfully conjugated to poly(ethylene glycol) (PEG) which was further encapsulated into the hydrophobic poly(3- caprolactone) (PCL) nanoparticles (NPs) with high efficiency, average particle size of 241.8 4 nm and negative zeta potential. Toxicity against erythrocytes and MDBK cell lines and drug release in human plasma were evaluated. Hemocompatibility and reduced cytotoxicity of the PEG–Mox and PCL(PEG– Mox) NPs were demonstrated in comparison to free Mox. Antimicrobial activity was assessed against drug sensitive and resistant: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The antibacterial activity of Mox was largely maintained after conjugation. Our data shows that the toxicity of Mox can be effectively attenuated while, in the case of PEG–Mox, retaining significant antibacterial activity. At the conditions employed in this study for antimicrobial activity the encapsulated conjugate (PCL(PEG–Mox) NPs) did not demonstrate, conclusively, significant antibacterial activity. These systems do, however, hold promise if further developed for improved treatment of bacterial infections.The National Research Foundation of South Africa and the Ministry of Higher Education and Scientific Research, Egypt.http://pubs.rsc.org/en/journals/journalissues/raam2021Chemistr

Quantum Interference in Superconducting Wire Networks and Josephson Junction Arrays: Analytical Approach based on Multiple-Loop Aharonov-Bohm Feynman Path-Integrals

We investigate analytically and numerically the mean-field superconducting-normal phase boundaries of two-dimensional superconducting wire networks and Josephson junction arrays immersed in a transverse magnetic field. The geometries we consider include square, honeycomb, triangular, and kagome' lattices. Our approach is based on an analytical study of multiple-loop Aharonov-Bohm effects: the quantum interference between different electron closed paths where each one of them encloses a net magnetic flux. Specifically, we compute exactly the sums of magnetic phase factors, i.e., the lattice path integrals, on all closed lattice paths of different lengths. A very large number, e.g., up to $10^{81}$ for the square lattice, exact lattice path integrals are obtained. Analytic results of these lattice path integrals then enable us to obtain the resistive transition temperature as a continuous function of the field. In particular, we can analyze measurable effects on the superconducting transition temperature, $T_c(B)$, as a function of the magnetic filed $B$, originating from electron trajectories over loops of various lengths. In addition to systematically deriving previously observed features, and understanding the physical origin of the dips in $T_c(B)$ as a result of multiple-loop quantum interference effects, we also find novel results. In particular, we explicitly derive the self-similarity in the phase diagram of square networks. Our approach allows us to analyze the complex structure present in the phase boundaries from the viewpoint of quantum interference effects due to the electron motion on the underlying lattices.Comment: 18 PRB-type pages, plus 8 large figure

Functional diversity of chemokines and chemokine receptors in response to viral infection of the central nervous system.

Encounters with neurotropic viruses result in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences to relatively benign infection. One of the principal factors that control the outcome of infection is the localized tissue response and subsequent immune response directed against the invading toxic agent. It is the role of the immune system to contain and control the spread of virus infection in the central nervous system (CNS), and paradoxically, this response may also be pathologic. Chemokines are potent proinflammatory molecules whose expression within virally infected tissues is often associated with protection and/or pathology which correlates with migration and accumulation of immune cells. Indeed, studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV), have provided important insight into the functional roles of chemokines and chemokine receptors in participating in various aspects of host defense as well as disease development within the CNS. This chapter will highlight recent discoveries that have provided insight into the diverse biologic roles of chemokines and their receptors in coordinating immune responses following viral infection of the CNS