Search results for "mass"

Synthesis and solution properties of star-shaped poly(tert-butyl acrylate)

2000

A series of star polymers consisting of poly(tert-butyl acrylate) arms and an ethyleneglycol dimethacrylate (EGDMA) microgel core were synthesized using anionic polymerization. The effect of various parameters (precursor length, ratio [[EGDMA]/[Initiator], reaction time, and overall concentrations) on the average number of arms was investigated. Molecular weights were determined using GPC coupled with an online viscometer and MALLS. The exponents for the relation between intrinsic viscosity or radius of gyration and molecular weight, respectively, are extremely low, indicating that the dimensions of the star polymers only slightly increase with the number of arms. After a certain number of …

Proteomic investigations to unravel molecular physiology of the lantibiotic producer Microbispora sp. ATCC‐PTA‐5024

2013

Study of Ni, Pt, and Ru Catalysts on Wood-based Activated Carbon Supports and their Activity in Furfural Conversion to 2-Methylfuran

2018

Bio‐based chemicals can be produced from furfural through hydrotreatment. In this study, 2‐methylfuran (MF), a potential biofuel component, was produced with Pt, Ru, and Ni catalysts supported on wood‐based activated carbons. The catalytic hydrotreatment experiments were conducted in a batch reactor at 210–240 °C with 2‐propanol as solvent and 40 bar H2 pressure. Two types of activated carbon supports were prepared by carbonization and activation of lignocellulosic biomass (forest‐residue‐based birch and spruce from Finland). Both types of activated carbons were suitable as catalyst supports, giving up to 100 % furfural conversions. The most important factors affecting the MF yield were the…

Carbons from second generation biomass as sustainable supports for catalytic systems

2018

In this study activated carbons were produced from the wood of three different wood species (pine, birch, spruce). The resulting activated carbons were characterized in bulk for ash content, carbon content (elemental analyses), specific surface area, and pore size distribution, and at the surface by measuring the autogenerated pH and studying their structure by XPS. All the samples presented high surface areas and appeared to be mesoporous materials (mesopores >80%). The carbons were then used as support for AuPt nanoparticles and tested in the liquid phase oxidation of glycerol (GLY) and in the hydrogenation of levulinic acid (LA), two important chemicals from cellulose-based biomass. The …

Application of LA-ICP-MS as a rapid tool for analysis of elemental impurities in active pharmaceutical ingredients.

2014

The control of inorganic contaminants in active pharmaceutical ingredients has a significant role in the quality control of drug products. The concentration limits for metal residues in drug products have been defined by various regulatory guidelines. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful and fast analytical technique for multi-elemental analysis. A disadvantage in using LA-ICP-MS method is the lack of matrix reference materials for validation and calibration purposes. This article focuses on the handling strategy of laboratory-made matrix calibration standards for the quantification of elemental impurities in an active pharmaceutical ingredie…

Prediction of Maxwell – Stefan diffusion coefficients in polymer – multicomponent fluid systems

2014

Abstract Calculations of mass fluxes in multicomponent fluids based on the system of generalized Maxwell–Stefan equations (GMSE) is preferably used because Maxwell–Stefan (M–S) diffusion coefficients are symmetrical and have a clear physical meaning, as they reflect the binary friction forces between compounds in the system. For the calculation of the mass transport of a multicomponent fluid in the polymer basing on GMSE, it is necessary to have M–S diffusion coefficients. This paper proposes a method that allows their calculation using widely available self-diffusion coefficients and binary diffusion coefficients for infinitely diluted mixtures. The proposed method was compared with the me…

Die bestimmung von sedimentationskoeffizient, diffusions-koeffizient und molekulargewicht von α-amylasen nach der methode des aktivitätstransportes

1965

Abstract Sedimentation and diffusion coefficients determined by optical methods on pure (crystallized) enzymes are compared with those obtained by activity measurements on the unpurified enzymes. On performing the experiments under suitable conditions, results of the two methods are in good agreement. The calculation of the molecular weights of the unpurified enzymes is somewhat uncertain because the partial specific volume in most cases is not accurately known.

Neuromuscular and mobility responses to a vibration session in hypoxia in multiple sclerosis

2020

AbstractThe aim of this study was to investigate the acute effects of vibration training (WBVT) under hypoxic and normoxic conditions on the voluntary rate of force development (RFD), balance and muscle oxygen saturation (SMO2) in persons with Multiple Sclerosis (MS). 10 participants completed the study (30% males, 44.4±7.7 years, 164.3±8.9 cm, 65.2±11.1 kg, 2.5±1.3 Expanded Disability Status Scale, 24.1±4.0 kg.m−2 BMI). Maximal force, RFD during isometric knee extension, static balance with eyes open and closed and sit-to-stand test were evaluated before and immediately after one session of WBVT (12 60-s bout of vibration; frequency 35 Hz; amplitude 4 mm; 1-min rest intervals) under both n…

Acute effects of different foam rolling volumes in the interset rest period on maximum repetition performance

2017

Background - Foam rolling (FR) is a ubiquitous intervention utilised for the purpose of acutely increasing the range of motion without subsequent decreases in performance. Thus, it is commonly used during the periworkout period—that is, prior to, during, or after an athlete's workout.\ud \ud Objective - This study investigated how different FR durations applied to the quadriceps during the interset rest periods affects the numbers of repetitions in the knee extension exercise.\ud \ud Methods - Twenty-five females completed four sets of knee extensions with 10 repetitions of maximum load to concentric failure on four occasions. Between each set, a 4-minute rest interval was implemented in wh…

Predictors of Early Death in Childhood Acute Promyelocytic Leukemia: Results of an International Retrospective Study

2015

Abstract Background: Acute promyelocytic leukemia (APL) is a rare subtype of childhood acute myeloid leukemia (AML). Bleeding complications occur in 80% of patients at diagnosis and contribute to a higher incidence of early death (ED) in APL compared to other AML subtypes. However, estimates of ED in pediatric APL are imprecise and factors associated with ED in children with APL are unknown. Objectives: To determine the incidence and predictors of ED, defined as death within 60 days from presentation, in childhood APL. Methods: We conducted a retrospective international analysis of children diagnosed with APL between January 1993 and December 2013. The study included 236 patients from the I…