Glycerol

We compared the effect of glycerol-induced hyperhydration (GIH) to that of water-induced hyperhydration (WIH) on cardiovascular and thermoregulatory functions and endurance performance (EP) during prolonged cycling in a temperate climate in subjects consuming fluid during exercise. At weekly intervals, 6 trained male subjects ingested, in a randomized, double-blind, counterbalanced fashion, either a glycerol (1.2 g glycerol/kg bodyweight (BW) with 26 mL/kg BW of water - aspartame-flavored fluid) or placebo solution (water - aspartame-flavored fluid only) over a 2 h period. Subjects then performed 2 h of cycling at 66% of the maximal oxygen consumption (VO2 max) and 25 °C while drinking 500 mL/h of sports drink, which was followed by a step-incremented cycling test to exhaustion. Levels of hyperhydration did not differ significantly between treatments before exercise. During exercise, GIH significantly reduced urine production by 246 mL. GIH did not increase sweat rate nor did it dec...

SYNOPSIS. An age-autolyzed culture of Chroomonas salina, grown under cool-white light with glycerol, produced waxy lipid constituting about 44% of total matter harvested. This lipid was composed of 87% wax ester, 9% triglyceride, 3% polar lipid and 1% hydrocarbon. The major wax ester species were identified by total carbon number as C26(28%), C28(35%), C30(15%). The main fatty acid components of the wax esters were 12:0 (39%), 14:0 (30%), 16:0 (14%), while the main alcohols were 14:0 (53%) and 16:0 (40%). The hydrocarbon fraction showed saturated paraffins ranging from C17 to C33, with odd-numbered chain components predominating. No polyunsaturated components were detected in the wax ester or hydrocarbon fractions. This is the first record of wax ester production by a cryptomonad or a marine phytoplankter.

Background  High-quality methods for lipoprotein characterization are warranted in studies on various metabolic diseases.Materials and methods  An automated system for size-exclusion chromatography (SEC) of lipoproteins using commercially available components is described. Cholesterol or triglyceride content in separated lipoproteins from plasma and interstitial fluid (IF) was continuously determined on-line using microlitre sample volumes.Results  The lipoprotein assay showed a good concordance with the classic ultra-centrifugation/precipitation technique using fresh or frozen samples. Determination of lipoproteins in IF obtained from vacuum-induced skin blisters from 18 healthy subjects revealed that very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol levels were 18%, 19% and 25%, respectively, of concomitant plasma concentrations. The size-exclusion chromatography (SEC) system also allows for triglyceride determination on-line and it could be shown that the system is advantageous for an accurate determination of triglycerides in conditions when there are high levels of glycerol, e.g. in mice and in patients with hyperglycerolaemia (pseudo-hypertriglyceridaemia).Conclusions  The described system should be of value in studies where detailed lipoprotein analysis is warranted and particularly when significant sample series with small volumes are available. Our data also suggest that there is a 4–5·5-fold concentration gradient between plasma and IF for the three major plasma lipoproteins.

Dehydration/condensation reactions between organic molecules in the prebiotic environment increased the inventory and complexity of organic compounds available for self-assembly into primitive cellular organisms. As a model of such reactions and to demonstrate this principle, we have investigated the esterification reaction between glycerol and decanoic acid that forms glycerol monodecanoate (GMD). This amphiphile enhances robustness of self-assembled membranous structures of carboxylic acids to the potentially disruptive effects of pH, divalent cation binding and osmotic stress. Experimental variables included temperature, water activity and hydrolysis of the resulting ester product, providing insights into the environmental conditions that would favor the formation and stability of this more evolved amphiphile. At temperatures exceeding 50 degrees C, the ester product formed even in the presence of bulk water, suggesting that the reaction occurs at the liquid interface of the two reactants and that the products segregate in the two immiscible layers, thereby reducing hydrolytic back reactions. This implies that esterification reactions were likely to be common in the prebiotic environment as reactants underwent cycles of wetting and drying on rare early landmasses at elevated temperatures.

The present study aimed to produce verapamil hydrochloride-loaded solid lipid microparticles (SLM) by the w/o/w emulsion solvent evaporation technique, using diethyl ether as solvent phase, glyceryl monostearate as biodegradable polymer and Span 60 as surfactant. SLM of spherical shape were prepared by simple dilution of the emulsion with water. To increase the lipid load the process was conducted at 50 degrees C, and in order to reach sub-micron size, a high-shear homogenizer was used. The encapsulation efficiency of prepared SLM reached 74.29 +/- 0.76%. Particle size (98.55 +/- 1.42 microm), surface morphology (spherical) and drug loading efficiency (18.57 +/- 1.25% w/w) were investigated. And optimization of drug polymer ratio (3:1), nature and concentration of emulsion stabilizer in the external aqueous (0.1%), phase viscosity of external aqueous phase (0.5%), volume of external aqueous phase and stirring rate (1000 rpm) were detected. Analysis of microsphere content after proce...

Chronic myalgia is associated with higher muscle levels of certain algesic biomarkers. The aim of this study was to investigate if hypertonic saline-induced jaw myalgia also leads to release of such biomarkers and if there were any sex differences in this respect. Healthy participants, 15 men and 15 aged-matched women (25.7 ± 4.3 years) participated. Intramuscular microdialysis into masseter muscles was performed to sample serotonin (5-HT), glutamate, lactate, pyruvate, glucose and glycerol. After 2 hours 0.2 mL hypertonic saline (58.5 mg/mL) was injected into the masseter on one side and 0.2 mL isotonic saline (9 mg/mL) into the contralateral masseter close to the microdialysis catheter. Microdialysis continued for 1 hour after the injections. Pressure pain thresholds (PPT) and pain were assessed before and after injections. The median (IQR) peak pain intensity (0-100 visual analogue scale) after hypertonic saline was 52.5 (38.0) and after isotonic saline 7.5 (24.0) (p < 0.05). ...

The effects of two methods of cryopreservation involving chemical vitrification and air desiccation) were studied on isolated embryonic axes of A. hypogaea. Vitrification with PVS2 and desiccation in a laminar flow cabinet resulted in high levels (70-90%) of whole plant recovery after cryopreservation. A desiccation protocol based on 1h exposure of explants to the air flow was successfully applied to six wild species of section Extranervosae, resulting in recovery levels of 70-90% after liquid nitrogen treatment.

The metabolic and hormonal changes during a standard physical exercise were studied in healthy subjects and in insulin-dependent diabetics well matched for body weight, and therefore submitted to a similar work load in a physiologic range, and in obese subjects that, owing to their weight, faced a significant heavier work in the same environmental conditions. Moderate work load did not lead to significant changes in metabolic and hormonal blood parameters (blood glucose, FFA and glycerol; insulin, glucagon, growth hormone and cortisol) in healthy subjects. A similar substrate homeostasis was seen in insulin-dependent diabetics, that however showed marked hormonal alterations. In these subjects, indeed, higher levels of plasma glucagon and GH were reached during work and in the recovery phase. Obese subjects, submitted to a heavier work load, presented a marked increase in blood glucose and glycerol which agrees with high GH and cortisol levels, and a subsequent increment of IRI which corresponds to a normalization of blood glucose and glycerol. Obese subjects, therefore, show a normal sensitivity to work load. Considerations about the work load in everyday life are discussed.

Blood oxygenation is the main performance characteristic of capillary membrane oxygenators (CMOs). Handling of natural blood in in vitro investigations of CMOs is quite complex and time-consuming. Since the conventional blood analog fluids (e.g. water/glycerol) lack a substance with an affinity to capture oxygen comparable to hemoglobin's affinity, in this study a novel approach using modified sulfite solution is proposed to address this challenge. The solution comprises sodium sulfite as a component, simulating the role of hemoglobin in blood oxygenation. This approach is validated by OTR (oxygen transfer rate) measured using native porcine blood, in two types of commercially available CMOs. Consequently, the number of complicated natural blood investigations in the evolution procedure of newly developed oxygenators would considerably decrease. Moreover, the reassessing of failed devices, in clinics, would be performed more precisely using a modified sulfite solution than simple water/glycerol testing.

Biohydrogen production from crude glycerol (CG) was investigated. Continuous packed bed reactor and mixed acidogenic consortia were used. pH was shown to be the crucial parameter affecting conversion efficiency. Hydrogen yield was affected by pH, HRT and organic loading rate. Hexanoate, a platform chemical, was produced to considerable amounts from CG. a b s t r a c t A continuous attached growth process for the production of biohydrogen from crude glycerol was developed. The process consisted of an anaerobic up-flow column bioreactor (UFCB), packed with cylindrical ceramic beads, which constituted the support matrix for the attachment of bacterial cells. The effect of crude glycerol concentration, pH and hydraulic retention time on glycerol conversion, hydrogen yield and metabolite distribution was investigated. It was shown that the most critical parameter for the efficient bioconversion was the pH of the influent, whereas the hydrogen yield increased with an increase in feed glycerol concentration and a decrease in the hydraulic retention time. The main soluble metabolite detected was 1,3-propanediol in all cases, followed by butyric and hexanoic acids. The latter is reported to be produced from glycerol for the first time. Acidification of the waste reached 38.5%, and the maximum H 2 productivity was 107.3 ± 0.7 L/kg waste glycerol at optimal conditions.

This study aimed to gain a deep understanding of the preparation mechanism of the thermoplastic potato starch (TPPS) by using melt-mixing as a production method, to pursue the changes occurred on the microstructure, morphology and thermal properties of potato starch, TPPS was prepared using a mixture of potato starch with glycerol and water as plasticizer in an internal mixer. The steps of the phase transition , happening by applying harsh conditions (60 rpm, 160 °C, and 7 min), were followed by monitoring the evolution of torque during the mixing time. It was shown that the granules structure was destroyed and a new phase was formed. This was proved by SEM which gave the evidence that the morphology of the TPPS was homogeneous with the smooth surface means that the mixing conditions used in this work were good enough to obtain the thermoplastic starch with a high level of homogeneity in all dimensions. FTIR analysis allowed deducing the formation of new H-bonds between the starch and plasticizers molecules instead of intra and intermo-lecular H-bonds in the native starch that was destructed through the melt-mixing process., These caused starch chains gain mobility and as the results decreasing in crystallinity, where the XRD analysis exhibited that the crystallinity decreased from 14.5% resulting from B-type in native potato starch to 9% resulting from B-type and VH-type in TPPS. TGA and DSC analysis proved a decreasing in the thermal stability in the TPPS as compared to the starch granules.

Biodiesel production from abundant bio-sources has drawn the attention of the academic as well as the industrial communities in recent years. However, one of the most serious obstacles for using biodiesel as an alternative fuel is the complicated and costly purification processes involved in its production. The difficulties involved in the separation of glycerine and other un-reacted reactants and by-products necessitate the development of new competent low cost separation processes for this purpose. In this work, a low cost quaternary ammonium salt–glycerine-based ionic liquid is proposed as a solvent for extracting glycerine from the transesterification biodiesel product. The separation technique was tested on palm oil-based produced biodiesel with KOH as a reaction catalyst. The study investigated the effect of DES:biodiesel ratio and the DES composition on the efficiency of the extraction process. The lab scale purification experiments proved the viability of the separation technique with a best DES:biodiesel molar ratio of 1:1 and a DES molar composition of 1:1 (salt:glycerine). The purified biodiesel fulfilled the EN 14214 and ASTM D 6751 standard specifications for biodiesel fuel in terms of glycerine content. A continuous separation process is suggested for industrial scale application.