Synthesis and Characterization of Polymer (Sulfonated Poly-ether-ether-ketone) Based Nanocomposite (h-boron nitride) Membrane for Hydrogen Storage

The development of light weight and compact hydrogen storage materials is still prerequisite to fuel-cell technology to be fully competitive. The present experimental study reports the hydrogen storage capability of sulfonated poly-ether-ether-ketone (SPEEK)-hexagonal boron nitride (h-BN) (SPEEK-h-BN) nanocomposite membranes. The nanocomposite membranes are prepared by considering various amount of h-BN (0, 1, 3 and 5 wt. %) by phase inversion technique. The degree of sulfonation of the PEEK (SPEEK) is found to be 65% by Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Hydrogen adsorption studies have been carried out using a Seiverts-like hydrogenation setup. The membranes are characterized by X-ray Diffractometer (XRD), Micro-Raman spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), CHN-elemental analysis and Thermo Gravimetric Analysis (TGA). It is observed that the SPEEK-5% h-BN membrane performs better than pure SPEEK membrane, has maximum storage capacity of 2.98 wt. % at 150 °C and the adsorbed hydrogen has an average binding energy of 0.38 eV. The TGA study shows the dehydrogenation behavior of hydrogenated SPEEK-h-BN nanocomposite membrane and it is found to be in the temperature range of 214–218 °C for SPEEK-5% h-BN membrane

The N Terminus of Sarcolipin Plays an Important Role in Uncoupling Sarco-endoplasmic Reticulum Ca²⁺-ATPase (SERCA) ATP Hydrolysis from Ca²⁺ Transport

The sarcoendoplasmic reticulum Ca(2+)-ATPase (SERCA) is responsible for intracellular Ca(2+) homeostasis. SERCA activity in muscle can be regulated by phospholamban (PLB), an affinity modulator, and sarcolipin (SLN), an uncoupler. Although PLB gets dislodged from Ca(2+)-bound SERCA, SLN continues to bind SERCA throughout its kinetic cycle and promotes uncoupling of Ca(2+) transport from ATP hydrolysis. To determine the structural regions of SLN that mediate uncoupling of SERCA, we employed mutagenesis and generated chimeras of PLB and SLN. In this study we demonstrate that deletion of SLN N-terminal residues (2)ERSTQ leads to loss of the uncoupling function even though the truncated peptide can target and constitutively bind SERCA. Furthermore, molecular dynamics simulations of SLN and SERCA interaction showed a rearrangement of SERCA residues that is altered when the SLN N terminus is deleted. Interestingly, transfer of the PLB cytosolic domain to the SLN transmembrane (TM) and luminal tail causes the chimeric protein to lose SLN-like function. Further introduction of the PLB TM region into this chimera resulted in conversion to full PLB-like function. We also found that swapping PLB N and C termini with those from SLN caused the resulting chimera to acquire SLN-like function. Swapping the C terminus alone was not sufficient for this conversion. These results suggest that domains can be switched between SLN and PLB without losing the ability to regulate SERCA activity; however, the resulting chimeras acquire functions different from the parent molecules. Importantly, our studies highlight that the N termini of SLN and PLB influence their respective unique functions

Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (< 5 years, 5–10 years, 10–20 years, and > 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (< 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs > 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (< 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs > 20 years: 0.62), and only surgeons with > 20 years of experience did not have substantial reliability on assessment 2 (< 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs > 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

Hydrogen Adsorption Properties of Multiwalled carbon nanotubes -Hexagonal Boron Nitride Nanocomposite

Abstract: Hydrogen is considered as a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density and environment friendly, but one of the major problems limiting the use of hydrogen for energy applications is the difficulty of storing it safely. In this work, the hydrogen storage performance of acid treated multi-walled carbon nanotubes (MWCNT)/hexagonal boron nitride (h-BN) (MWCNT/h-BN) nano composite is investigated. The MWCNT/h-BN nanocomposite is prepared by using drop cast method. The hydrogenation of acid treated MWCNTs and MWCNT/h-BN nano composite have been carried out using Seiverts like apparatus. The prepared nanocomposites were characterized by X-ray Diffraction (XRD), micro-Raman spectroscopy, Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), CHN-elemental analysis and Thermo Gravimetric Analysis (TGA). The amount of hydrogen stored in MWCNT/h-BN nanocomposite is found to be 1.6 wt. % at 100 ºC and the average binding energy of stored hydrogen is 0.48 eV

High gender -specific susceptibility to curare- a neuromuscular blocking agent

Curare, a selective skeletal muscle relaxant, has been used clinically to reduce shivering and as an anesthetic auxiliary in abdominal surgery. It is also widely used in animal experiments to block neuromuscular junction activity. Effective doses of curare diminish muscle contraction without affecting brain function, but at higher doses it is known to be lethal. However, the exact dose of curare initiating muscle relaxation vs. lethal effect has not been fully characterized in mice. In this study we carefully examined the dose-response for achieving muscle inactivity over lethality in both male and female mice (C57BL6/J). The most striking finding of this study is that female mice were highly susceptible to curare; both the EDm and LDm were at least 3-fold lower than male littermates. This study shows that gender-specific differences can be an important factor when administering skeletal muscle relaxants, particularly curare or other analogous agents targeted to the neuromuscular junction

Clindamycin Induced Dysphagia – A Rare Concurrence

Although dysphagia is a mechanical impedance in phase specific mechanism, drug induced dysphagia is an adverse event often caused due to esophagitis. Clindamycin is well known to cause esophagitis; itself causing dysphagia is not reported in literature. Herein, we report one such case recently seen by us who was diagnosed with Clindamycin induced dysphagia post debridement surgery for acute necrotizing fasciitis

Clindamycin Induced Dysphagia – A Rare Concurrence

Abstract: Although dysphagia is a mechanical impedance in phase specific mechanism, drug induced dysphagia is an adverse event often caused due to esophagitis. Clindamycin is well known to cause esophagitis; itself causing dysphagia is not reported in literature. Herein, we report one such case recently seen by us who was diagnosed with Clindamycin induced dysphagia post debridement surgery for acute necrotizing fasciitis

Metabolic dysfunction and altered mitochondrial dynamics in the utrophin-dystrophin deficient mouse model of duchenne muscular dystrophy.

The utrophin-dystrophin deficient (DKO) mouse model has been widely used to understand the progression of Duchenne muscular dystrophy (DMD). However, it is unclear as to what extent muscle pathology affects metabolism. Therefore, the present study was focused on understanding energy expenditure in the whole animal and in isolated extensor digitorum longus (EDL) muscle and to determine changes in metabolic enzymes. Our results show that the 8 week-old DKO mice consume higher oxygen relative to activity levels. Interestingly the EDL muscle from DKO mouse consumes higher oxygen per unit integral force, generates less force and performs better in the presence of pyruvate thus mimicking a slow twitch muscle. We also found that the expression of hexokinase 1 and pyruvate kinase M2 was upregulated several fold suggesting increased glycolytic flux. Additionally, there is a dramatic increase in dynamin-related protein 1 (Drp 1) and mitofusin 2 protein levels suggesting increased mitochondrial fission and fusion, a feature associated with increased energy demand and altered mitochondrial dynamics. Collectively our studies point out that the dystrophic disease has caused significant changes in muscle metabolism. To meet the increased energetic demand, upregulation of metabolic enzymes and regulators of mitochondrial fusion and fission is observed in the dystrophic muscle. A better understanding of the metabolic demands and the accompanied alterations in the dystrophic muscle can help us design improved intervention therapies along with existing drug treatments for the DMD patients