Preparation and some properties of nylon-4,2

An attempt was made to produce a new short-chain alphatic polyamide nylon-4,2. This polyoxamide can be prepared by polycondensation of tetramethylene diamine and diethyl oxalate. A high molecular weight polymer (ηinh = 1.9 from 0.5% solutions in 96% sulphuric acid) has been obtained by employing a two-step polycondensation method; the precondensation was carried out in solution at low temperatures (20-140°C) and the postcondensation in the solid state at high temperatures (250-300°C). The effect of solvent composition and reaction temperature on the prepolymerization and the effect of reaction time and temperature on the postcondensation was studied. We also investigated the influence of moisture during washing, storing, and the solid-state reaction on the polymerizability by the postcondensation. Nylon-4,2 is soluble only in highly polar solvents such as trifluoroacetic acid (TFA), dichloroacetic acid, and 96% sulphuric acid. Films were cast from TFA. With these films we studied the IR spectrum, WAXS pattern, water absorption, and melting behavior. Nylon-4,2 was found to melt at 388-392°C, has a crystallinity of 70%, and a low water absorption (3.1% at 50% RH). The glass transition temperature of the dry sample was found to be at ~120°C and for the wet sample at -15°C

Impact of nuclear vibrations on van der Waals and Casimir interactions at zero and finite temperature

Van der Waals (vdW) and Casimir interactions depend crucially on material properties and geometry, especially at molecular scales, and temperature can produce noticeable relative shifts in interaction characteristics. Despite this, common treatments of these interactions ignore electromagnetic retardation, atomism, or contributions of collective mechanical vibrations (phonons) to the infrared response, which can interplay with temperature in nontrivial ways. We present a theoretical framework for computing electromagnetic interactions among molecular structures, accounting for their geometry, electronic delocalization, short-range interatomic correlations, dissipation, and phonons at atomic scales, along with long-range electromagnetic interactions among themselves or in the vicinity of continuous macroscopic bodies. We find that in carbon allotropes, particularly fullerenes, carbyne wires, and graphene sheets, phonons can couple strongly with long-range electromagnetic fields, especially at mesoscopic scales (nanometers), to create delocalized phonon polaritons that significantly modify the infrared molecular response. These polaritons especially depend on the molecular dimensionality and dissipation, and in turn affect the vdW interaction free energies of these bodies above a macroscopic gold surface, producing nonmonotonic power laws and nontrivial temperature variations at nanometer separations that are within the reach of current Casimir force experiments.Comment: 11 pages, 4 figures (3 single-column, 1 double-column), 2 appendice

A rare case of successful twin pregnancy in bicorporeal septate uterus with co-existent septate cervix

Pregnancy occurring in patients with uterine malformations need to be managed with care as they are at risk of developing adverse outcomes. Multiple pregnancies in patients with uterine abnormalities further increase the risk of complications.  Due to the rarity of this problem, there are no recommendations to guide and plan the management of these patients. Delivery planning is also tricky and needs to be individualised as either mode of delivery can be associated with complications. We discuss the management of a twin pregnancy in a primigravida (conceived after ovulation induction) with Mullerian abnormality- Septate uterus with co-existent septate cervix; ESHRE type U-2B C-1

A Request-TDMA Multiple-Access Scheme for Wireless Multimedia Networks

This paper describes a cellular multiple-access scheme based on TDMA for multimedia communication networks. The scheme proposes an admission control of two different multimedia application stream types: real-time and non-real-time. We do not consider interference between cells. The proposed protocol, that is based on TDMA, exploits the available bandwidth fully. The throughput per mobile station is higher compared to other multiple-access protocols, it offers low latency for both real-time and non-real-time communication and the unused reserved bandwidth is reallocated for non-real-time communication. Furthermore, the throughput and latency remain stable under high loads

Ayurveda and Epilepsy

This article does not have an abstract

Toward identifying reproducible brain signatures of obsessive-compulsive profiles: rationale and methods for a new global initiative

Background Obsessive-compulsive disorder (OCD) has a lifetime prevalence of 2–3% and is a leading cause of global disability. Brain circuit abnormalities in individuals with OCD have been identified, but important knowledge gaps remain. The goal of the new global initiative described in this paper is to identify robust and reproducible brain signatures of measurable behaviors and clinical symptoms that are common in individuals with OCD. A global approach was chosen to accelerate discovery, to increase rigor and transparency, and to ensure generalizability of results. Methods We will study 250 medication-free adults with OCD, 100 unaffected adult siblings of individuals with OCD, and 250 healthy control subjects at five expert research sites across five countries (Brazil, India, Netherlands, South Africa, and the U.S.). All participants will receive clinical evaluation, neurocognitive assessment, and magnetic resonance imaging (MRI). The imaging will examine multiple brain circuits hypothesized to underlie OCD behaviors, focusing on morphometry (T1-weighted MRI), structural connectivity (Diffusion Tensor Imaging), and functional connectivity (resting-state fMRI). In addition to analyzing each imaging modality separately, we will also use multi-modal fusion with machine learning statistical methods in an attempt to derive imaging signatures that distinguish individuals with OCD from unaffected siblings and healthy controls (Aim #1). Then we will examine how these imaging signatures link to behavioral performance on neurocognitive tasks that probe these same circuits as well as to clinical profiles (Aim #2). Finally, we will explore how specific environmental features (childhood trauma, socioeconomic status, and religiosity) moderate these brain-behavior associations. Discussion Using harmonized methods for data collection and analysis, we will conduct the largest neurocognitive and multimodal-imaging study in medication-free subjects with OCD to date. By recruiting a large, ethno-culturally diverse sample, we will test whether there are robust biosignatures of core OCD features that transcend countries and cultures. If so, future studies can use these brain signatures to reveal trans-diagnostic disease dimensions, chart when these signatures arise during development, and identify treatments that target these circuit abnormalities directly. The long-term goal of this research is to change not only how we conceptualize OCD but also how we diagnose and treat it

Ispitivanje kompatibilnosti nateglinida s pomoćnim tvarima u razvoju tableta nateglinida za trenutno oslobađanje

Experiments were done to assess the compatibility of nateglinide with selected excipients in the development of immediate release tablets of nateglinide by thermal and isothermal stress testing (IST) techniques. To evaluate the drug-excipient compatibility, different techniques such as differential scanning calorimetric (DSC) study, infra-red (IR) spectrophotometric study and isothermal stress testing were adopted. The results of DSC study showed that magnesium stearate exhibited some interaction with nateglinide. However, the results of IR, and IST studies showed that all the excipients used in the formula were compatible with nateglinide. Optimized formulations developed using the compatible excipients were found to be stable over 3 months of accelerated stability studies (40 ± 2 C and 75 ± 5 % RH). Overall, compatibility of excipients with nateglinide was successfully evaluated using a combination of thermal and IST methods and the formulations developed using the compatible excipients were found to be stable.Koristeći termičke metode kao što su diferencijalna pretražna kalorimetrija (DSC) i infra-crvena spektrofotometrija (IR), te izotermička stres-testiranja (IST) ispitana je kompatibilnost nateglinida s izabranim ekscipiensima u razvoju tableta nateglinida za trenutno oslobađanje. Rezultati DSC ispitivanja pokazala su da magnezijev stearat stupa u određenu interakciju s nateglinidom. Međutim, IR i IST ispitivanja pokazuju da su svi upotrijebljeni ekscipiensi kompatibilni s nateglinidom. Optimirana formulacija bila je stabilna preko 3 mjeseca u testovima ubrzanog starenja (40 ± 2 C i 75 ± 5 % RH). Kompatibilnost ekscipiensa s nateglinidom uspješno je evaluirana koristeći kombinaciju termičke i IST metode, a formulacije razvijene koristeći kompatibilne ekscipiense bile su stabilne

Stochastic signalling rewires the interaction map of a multiple feedback network during yeast evolution

During evolution, genetic networks are rewired through strengthening or weakening their interactions to develop new regulatory schemes. In the galactose network, the GAL1/GAL3 paralogues and the GAL2 gene enhance their own expression mediated by the Gal4p transcriptional activator. The wiring strength in these feedback loops is set by the number of Gal4p binding sites. Here we show using synthetic circuits that multiplying the binding sites increases the expression of a gene under the direct control of an activator, but this enhancement is not fed back in the circuit. The feedback loops are rather activated by genes that have frequent stochastic bursts and fast RNA decay rates. In this way, rapid adaptation to galactose can be triggered even by weakly expressed genes. Our results indicate that nonlinear stochastic transcriptional responses enable feedback loops to function autonomously, or contrary to what is dictated by the strength of interactions enclosing the circuit