Foamability of Cellulose Palmitate Using Various Physical Blowing Agents in the Extrusion Process

Polymer foams are widely used in several fields such as thermal insulation, acoustics, automotive, and packaging. The most widely used polymer foams are made of polyurethane, polystyrene, and polyethylene but environmental awareness is boosting interest towards alternative bio-based materials. In this study, the suitability of bio-based thermoplastic cellulose palmitate for extrusion foaming was studied. Isobutane, carbon dioxide (CO(2)), and nitrogen (N(2)) were tested as blowing agents in different concentrations. Each of them enabled cellulose palmitate foam formation. Isobutane foams exhibited the lowest density with the largest average cell size and nitrogen foams indicated most uniform cell morphology. The effect of die temperature on foamability was further studied with isobutane (3 wt%) as a blowing agent. Die temperature had a relatively low impact on foam density and the differences were mainly encountered with regard to surface quality and cell size distribution. This study demonstrates that cellulose palmitate can be foamed but to produce foams with greater quality, the material homogeneity needs to be improved and researched further

Management of Adult Dengue Shock Syndrome Patients Not Improving with DEAG Guidelines Based Therapy

Background: Dengue Expert Advisory Group (DEAG) guidelines are used for management of dengue patients in our scenario. It was observed in last consecutive dengue epidemics at Rawalpindi that some of the dengue shock syndrome (DSS) patients don’t improve unless modifications in DEAG guidelines are made. This study was conducted to evaluate modified DEAG management guidelines in DSS patients with decompensated shock who were not improving with treatment based on standard DEAG guidelines.Methods: This quasi experimental study was conducted at Dengue Units of Hospitals attached with Rawalpindi Medical College during Rawalpindi dengue epidemic 2015. Dengue Shock Syndrome (DSS) patients who were not improving with DEAG guidelines based treatment, were managed as per modified treatment plan i.e., continuing with colloid or blood depending on HCT in tapering way for initial few hours after hemodynamic stabilization is achieved. Outcome was recorded in terms of improvement/recovery and mortality. Poor outcome (mortality was correlated with mean age, gender, primary or secondary dengue infection, presence of additional illnesses and mean duration of hospital stay by Chi2 and t test wherever relevant.Results: Seventeen patients were included in the study. 64.7% were female. Mean patient age was 31.29±9.56 years. Thirteen patients (76.47%) recovered and were discharged. Four patients (23.52%) expired. Poor outcome had statistically significant association with presence of additional illnesses and shorter duration of hospital stay (p value <0.05).Conclusion: Modification in DEAG treatment plan lead to better outcome in majority of DSS patients who did not improve with DEAG standard management

Self-Assembly of Amphiphilic Janus Dendrimers into Mechanically Robust Supramolecular Hydrogels for Sustained Drug Release

Peer reviewe

High-Generation Amphiphilic Janus-Dendrimers as Stabilizing Agents for Drug Suspensions

Pharmaceutical nanosuspensions are formed when drug crystals are suspended in aqueous media in the presence of stabilizers. This technology offers a convenient way to enhance the dissolution of poorly water-soluble drug compounds. The stabilizers exert their action through electrostatic or steric interactions, however, the molecular requirements of stabilizing agents have not been studied extensively. Here, four structurally related amphiphilic Janus-dendrimers were synthesized and screened to determine the roles of different macromolecular domains on the stabilization of drug crystals. Physical interaction and nanomilling experiments have substantiated that Janus-dendrimers with fourth generation hydro- philic dendrons were superior to third generation analogues and Poloxamer 188 in stabilizing indomethacin suspensions. Contact angle and surface plasmon resonance measurements support the hypothesis that Janus-dendrimers bind to indomethacin surfaces via hydrophobic interactions and that the number of hydrophobic alkyl tails determines the adsorption kinetics of the Janus-dendrimers. The results showed that amphiphilic Janus-dendrimers adsorb onto drug particles and thus can be used to provide steric stabilization against aggregation and recrystallization. The modular synthetic route for new amphiphilic Janus-dendrimers offers, thus, for the first time a versatile platform for stable general-use stabilizing agents of drug suspensions.Peer reviewe

Modular synthesis of self-assembling Janus-dendrimers and facile preparation of drug-loaded dendrimersomes

Materials and methods aimed at the next generation of nanoscale carriers for drugs and other therapeutics are currently in great demand. Yet, creating these precise molecular arrangements in a feasible and straightforward manner represents a remarkable challenge. Herein we report a modular synthetic route for amphiphilic Janus-dendrimers via a copper-catalyzed click reaction (CuAAC) and a facile procedure, using simple injection, to obtain highly uniform dendrimersomes with efficient loading of the model drug compound propranolol. The resulting assemblies were analyzed by dynamic light scattering and cryogenic transmission electronic microscopy revealing the formation of unilamellar and multilamellar dendrimersomes. The formation of a bilayer structure was confirmed using cryo-TEM and confocal microscopy visualization of an encapsulated solvatochromic dye (Nile red). The dendrimersomes reported here are tunable in size, stable over time and display robust thermal stability in aqueous media. Our results expand the scope of dendrimer-based supramolecular colloidal systems and offer the means for one-step fabrication of drug-loaded dendrimersomes in the size range of 90–200 nm, ideal for biomedical applications

Janus-dendrimer supramolecular structures as delivery agents for small molecules, peptides and proteins

Janus-dendrimers are synthetic amphiphiles formed by linking two chemically distinct hydrophilic and hydrophobic dendrons by their core, which can self-assemble as vesicles (dendrimersomes) or fibres in aqueous solutions, as well as in biological media. This research shows that the dendrimersome scan differentially encapsulate drug compounds, are stable for long periods of time, and can be annealed from 22 °C to 70 °C with minimal change (2-5 nm)in their hydrodynamic radius [1].Also, by modulating the hydrophilic branch generation we found that Janus-dendrimers were also able to self-assemble into a variety of other architectures such as fibres, giving rise to supramolecular hydrogels capable of encapsulating and releasing small molecules, peptides, and proteins[2],or even function as colloidal suspensions’ stabilizers [3].Thus, the small library of Janus-dendrimers reported herein expand the scope of dendrimer-based supramolecular drug delivery systems and suggest that these materials can be further used in biomedical sol–gel applications

Epitranscriptomics of Ischemic Heart Disease—The IHD-EPITRAN Study Design and Objectives

Epitranscriptomic modifications in RNA can dramatically alter the way our genetic code is deciphered. Cells utilize these modifications not only to maintain physiological processes, but also to respond to extracellular cues and various stressors. Most often, adenosine residues in RNA are targeted, and result in modifications including methylation and deamination. Such modified residues as N-6-methyl-adenosine (m6A) and inosine, respectively, have been associated with cardiovascular diseases, and contribute to disease pathologies. The Ischemic Heart Disease Epitranscriptomics and Biomarkers (IHD-EPITRAN) study aims to provide a more comprehensive understanding to their nature and role in cardiovascular pathology. The study hypothesis is that pathological features of IHD are mirrored in the blood epitranscriptome. The IHD-EPITRAN study focuses on m6A and A-to-I modifications of RNA. Patients are recruited from four cohorts: (I) patients with IHD and myocardial infarction undergoing urgent revascularization; (II) patients with stable IHD undergoing coronary artery bypass grafting; (III) controls without coronary obstructions undergoing valve replacement due to aortic stenosis and (IV) controls with healthy coronaries verified by computed tomography. The abundance and distribution of m6A and A-to-I modifications in blood RNA are charted by quantitative and qualitative methods. Selected other modified nucleosides as well as IHD candidate protein and metabolic biomarkers are measured for reference. The results of the IHD-EPITRAN study can be expected to enable identification of epitranscriptomic IHD biomarker candidates and potential drug targets