pH-sensitive gels: By using a cyclohexane-based scaffold to which various amino acid based substituents can be connected, low-molecular-weight compounds were obtained that can gelate water at very low concentrations. Their modular design (see picture: AA = amino acid(s), X = hydrophilic substituent, dark purple = hydrophobic region, light purple = hydrophilic region), allows tuning of the thermally and pH-induced reversible gel-to-sol transition of their gels.
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The specific fibrinolytic properties of both high molecular weight (55 kd) and low molecular weight (30 kd) pro-urokinase from a monkey kidney cell culture were evaluated in a plasma clot lysis system and compared with those of human urokinase. The system was composed of a radiolabelled plasma clot immersed in plasma containing the fibrinolytic agent. On unit base, 55 kd pro-urokinase was approximately 1.5 times more effective in lysing the clot than 30 kd pro-urokinase and equally effective as urokinase. In contrast to urokinase, both pro-urokinase forms induced clot lysis without degrading fibrinogen in the surrounding plasma. However, a considerable activation of the fibrinolytic system in the plasma occurred as a large amount of alpha 2-antiplasmin was consumed, indicating that pro-urokinase was not fully fibrin-specific. Quenching antibodies against tissue-type plasminogen activator (t-PA) added to the plasma clot lysis system retarded but did not prevent pro-urokinase-induced clot lysis. This indicated that not only was t-PA in plasma involved in the activation of pro-urokinase (probably via plasmin), but that an additional mechanism also existed.
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The concurrent self-assembly of new 1,3,5-trisamide-cyclohexane-based low molecular weight hydrogelators and various surfactants in water leads to the formation of self-assembled fibrillar networks with encapsulated micelles. This prototype system presents an example of orthogonal self-assembly, that is, the independent formation of two different supramolecular structures, each with their own characteristics that coexist within a single system.
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Seven new 1,3,5-cyclohexyltricarboxamide-phenylalanine derivatives were synthesized in order to investigate the effect of the amino acid chirality on the gelating properties of these small molecules in water. Gelation tests have shown that enantiomerically pure homochiral 1,3,5-cyclohexyltricarboxamide-L-phenylalanine is a non-hydrogelator as it crystallizes from water, whereas the heterochiral derivatives with either two L-phenylalanine moieties and one D-phenylalanine (LLD), or vice versa (DDL), are very good hydrogelators. Concentration-dependent gel-to-sol transition-temperature (T(gs)) curves for LLD or DDL gels show a sigmoidal behaviour, which is in contrast to the logarithmic curves generally observed for gels derived from low molecular weight gelators (LMWGs). Such sigmoidal behaviour can be related to interactions between fibre bundles, which give rise to intertwined bundles of fibres. Transmission electron microscopy (TEM) images of LLD and DDL gels show a network of thin, unbranched, fibre bundles with diameters of 20 nm. Right-handed twisted fibre bundles are present in the LLD gel, whereas left-handed structures can be found in the DDL gel. Each bundle of fibres consists of a finite number of primary fibres. Gels consisting of mixtures of gelators, LLD and DDL, and nongelators (LLL or DDD) were investigated by means of T(gs) measurements, CD spectroscopy and TEM. Results show that the incorporation of nongelator molecules into gel fibres occurs; this leads to higher T(gs) values and to changes in the helicity of the fibre bundles. Furthermore, it was found that peripheral functionalization of the homochiral derivatives LLL or DDD by means of a second amino acid or a hydrophilic moiety can overcome the effect of chirality; this process in turn leads to good hydrogelators.
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The present invention relates to a novel process for the preparation of low molecular weight aromatic compounds such as benzene, toluene, and xylenes (BTX) from plastics. Provided is a thermo-catalytic pyrolysis process for the preparation of aromatic compounds from a feed stream comprising plastic, comprising the steps of: a) subjecting a feed stream comprising a plastic to a pyrolysis treatment at a pyrolysis temperature in the range of 600-1000°C to produce pyrolysis vapors; b) optionally cooling the pyrolysis vapors to a temperature that is below the pyrolysis temperature; c) contacting the vaporous phase with an aromatization catalyst at an aromatization temperature in the range of 450 - 700 °C, which aromatization temperature is at least 50°C lower than the pyrolysis temperature, in a catalytic conversion step to yield a conversion product comprising aromatic compounds; and d) optionally recovering the aromatic compounds from the conversion product.
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1. An earlier study by our group revealed that the viscosity of faeces from patients with Crohn's disease is significantly lower than that of healthy subjects. This is due to low concentrations of a high-molecular-mass carbohydrate, probably of bacterial origin. The cause of this phenomenon might be the impaired barrier function of the gut mucosa. Low viscosity may allow close contact of intestinal contents (bacterial products and toxins) with the intestinal wall. This could play a role in the maintenance of the disease.2. The first aim of this study was to investigate the high-molecular-mass carbohydrate fraction, responsible for viscosity, in detail. We also tried (in a pilot study) to raise the intestinal viscosity of patients with Crohn's disease with the undegradable food additive hydroxypropylcellulose (E463), in an attempt to alleviate clinical symptoms.3. The high-molecular-mass fraction (>300 kDa) responsible for faecal viscosity was sensitive to lysozyme and contained high levels of muramic acid. It was concluded that this material consisted mainly of peptidoglycan polysaccharides and was consequently of bacterial origin. The muramic acid in material from patients with Crohn's disease was 7.5 (1.5-13.9)%, which was less than in healthy subjects [11.4 (8.5-24.1)%; P=0.0004]. Furthermore, viscosity in material from patients with Crohn's disease was found to be half [14.9 (1.0-33.6) cP] of that found in healthy subjects [35.0 (2.7-90.7) cP; P=0.004].4.A daily dose of 1 g of hydroxypropylcellulose caused an increase in faecal viscosity in patients with Crohn's disease (from 1.4 to 2.3 cP) and in healthy subjects (from 4.9 to 7.5 cP). Faecal consistency improved in patients with Crohn's disease (from watery and loose to formed) and the defecation frequency decreased from 3-4 to about 2 times a day. No changes in defecation patterns were found in healthy subjects.5. These data indicate that the high-molecular-mass fraction that is responsible for faecal viscosity is peptidoglycan. Furthermore, a daily dose of a hydroxypropylcellulose solution to increase the viscosity of the intestinal contents of patients with Crohn's disease might be beneficial. This approach merits further study.
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Background Physical activity after bariatric surgery is associated with sustained weight loss and improved quality of life. Some bariatric patients engage insufficiently in physical activity. The aim of this study was to examine whether and to what extent both physical activity and exercise cognitions have changed at one and two years post-surgery, and whether exercise cognitions predict physical activity. Methods Forty-two bariatric patients (38 women, 4 men; mean age 38 ± 8 years, mean body mass index prior to surgery 47 ± 6 kg/m²), filled out self-report instruments to examine physical activity and exercise cognitions pre- and post surgery. Results Moderate to large healthy changes in physical activity and exercise cognitions were observed after surgery. Perceiving less exercise benefits and having less confidence in exercising before surgery predicted less physical activity two years after surgery. High fear of injury one year after surgery predicted less physical activity two years after surgery. Conclusion After bariatric surgery, favorable changes in physical activity and exercise cognitions are observed. Our results suggest that targeting exercise cognitions before and after surgery might be relevant to improve physical activity.
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Background: Adverse outcome pathway (AOP) networks are versatile tools in toxicology and risk assessment that capture and visualize mechanisms driving toxicity originating from various data sources. They share a common structure consisting of a set of molecular initiating events and key events, connected by key event relationships, leading to the actual adverse outcome. AOP networks are to be considered living documents that should be frequently updated by feeding in new data. Such iterative optimization exercises are typically done manually, which not only is a time-consuming effort, but also bears the risk of overlooking critical data. The present study introduces a novel approach for AOP network optimization of a previously published AOP network on chemical-induced cholestasis using artificial intelligence to facilitate automated data collection followed by subsequent quantitative confidence assessment of molecular initiating events, key events, and key event relationships. Methods: Artificial intelligence-assisted data collection was performed by means of the free web platform Sysrev. Confidence levels of the tailored Bradford-Hill criteria were quantified for the purpose of weight-of-evidence assessment of the optimized AOP network. Scores were calculated for biological plausibility, empirical evidence, and essentiality, and were integrated into a total key event relationship confidence value. The optimized AOP network was visualized using Cytoscape with the node size representing the incidence of the key event and the edge size indicating the total confidence in the key event relationship. Results: This resulted in the identification of 38 and 135 unique key events and key event relationships, respectively. Transporter changes was the key event with the highest incidence, and formed the most confident key event relationship with the adverse outcome, cholestasis. Other important key events present in the AOP network include: nuclear receptor changes, intracellular bile acid accumulation, bile acid synthesis changes, oxidative stress, inflammation and apoptosis. Conclusions: This process led to the creation of an extensively informative AOP network focused on chemical-induced cholestasis. This optimized AOP network may serve as a mechanistic compass for the development of a battery of in vitro assays to reliably predict chemical-induced cholestatic injury.
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A process for the prepn. of arom. compds. from a feed stream contg. biomass or mixts. of biomass, the process comprising: a) subjecting a feed stream contg. biomass or mixts. of biomass to a process to afford a conversion product comprising arom. compds.; b) recovering the arom. compds. from said conversion product; c) sepg. a higher mol. wt. fraction comprising polyarom. hydrocarbons (PAH) from a lower mol. wt. fraction comprising benzene, toluene and xylene (BTX) by distn.; d) reducing at least part of said higher mol. wt. fraction to obtain a reduced fraction comprising polycyclic aliphatics (PCA); and e) subjecting the higher mol. wt. fraction obtained in step c), the reduced fraction obtained in step d), or a mixt. thereof, to a process to obtain lower mol. wt. aroms. (BTX). [on SciFinder(R)]
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Understanding taste is key for optimizing the palatability of seaweeds and other non-animal-based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein-coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor-linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l-glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l-glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.
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