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Calorimetric studies on solid α-chymotrypsin preparations in air and in organic solvents

Differential scanning calorimetry was the method to investigate the thermostability of chymotrypsin. The transition temperature decreased by approx. 30°C when the dry enzyme became highly hydrated. High degree of hydration corresponded to extensive conformational changes during protein denaturation, reflected by large enthalpy values. Sorbitol, lyophilized together with the enzyme, caused the dest

Starch Complexing by Enzymatically Prepared 2‐Monoglycerides Compared to Effects by 1‐lsomers

In order to evaluate whether there are differences with regard to functionality in starch gel modification between 1‐and 2‐monoglycerides, the gelatinisation of potato starch in the presence of monolaurin, monopalmitin and monoolein has been examined. When the temperature was increased by 1°C/min from 20°C to 80°C there was a significant difference in gel volume between samples containing 1‐monola

Reaction kinetics of immobilized α chymotrypsin in organic media 2. Effects of substrate partition

The reaction kinetics of αchymotrypsin (EC 3.4.21.1.) catalyzed esterification of N-protected phenylalanine with ethanol were studied. The enzyme was deposited on Chromosorb and reactions were performed mainly in water-saturated mixtures of ethyl acetate and heptane, but also other media were used, such as mixtures of ethyl acetate and acetonitrile. The hydrophobicity of the substrate was varied b

Research highlights from the 2017 ERS International Congress : airway diseases in focus

For another year, high-quality research studies from around the world transformed the annual ERS International Congress into a vivid platform to discuss trending research topics, to produce new research questions and to further push the boundaries of respiratory medicine and science. This article reviews only some of the high-quality research studies on asthma, chronic obstructive pulmonary diseas

Amelioration of spatial memory impairment by intrahippocampal grafts of mixed septal and raphe tissue in rats with combined cholinergic and serotonergic denervation of the forebrain

Previous studies in the rat have shown that a serotonergic depletion greatly potentiates the learning and memory impairments produced by pharmacological or lesion-induced cholinergic blockade in the forebrain. The impairment produced by combined serotonergic-cholinergic lesions is reminiscent of that seen in memory-impaired aged rats. In the present experiment, we investigated whether grafts of ch

Klimatförändringen, ekosystem och arter

Den pågående klimatförändringen påverkar redan jordens arter och ekosystem på land, i sjöar, vid kusterna och i haven. Den påverkar enskilda arters utbredning och beteende, vilket i sin tur leder till förändringar i den biologiska mångfalden. Även om andra hot mot den biologiska mångfalden hittills dominerat, kommer effekterna på arter och ekosystem att öka med tilltagande klimatförändring med svå

Impact of Excess Lead Iodide on the Recombination Kinetics in Metal Halide Perovskites

Fundmental comprehension of light-induced processes in perovskites are still scarce. One active debate surrounds the influence of excess lead iodide (PbI2) on device performance, as well as optoelectronic properties, where both beneficial and detrimental traits have been reported. Here, we study its impact on charge carrier recombination kinetics by simultaneously acquiring the photoluminescence q

Modulation of the measuring range of a radioimmunoassay using an organic water two phase system

A commercially available radioimmunoassay (RIA) kit was used to study the effects of organic solvents on antigen-antibody interactions. The RIA analysis was carried out in aqueous-organic two phase systems. After exposure to hydrophobic organic solvents the antibodies retained full binding capacity, while less hydrophobic solvents caused partial inactivation of the antibodies. A practical analysis

Effects of subzero temperatures on the kinetics of protease catalyzed dipeptide synthesis in organic media

A depeptide synthesis was drastically influenced by the reaction temperature, in the range from −30° to 25°C. This article shows the kinetic reasons of this effect. α‐Chymotrypsin was immobilized on celite and used in four different water‐miscible solvents containing small amounts of water‐miscible solvents containing small amounts of water. The reaction studied was the aminolysis of N‐acetyl‐L‐ph

A differential scanning calorimetric study of chymotrypsin in the presence of added polymers

Scanning calorimetry measurements of different amounts of chymotrypsin in water alone gave a temperature of denaturation (Td) value of 54°C. However, when high‐molecular‐weight poly(ethylene glycol) was added to aqueous solutions of chymotrypsin, the thermostability of the enzyme was enhanced. For example, the addition of 20% (w/w) of poly(ethylene glycol) of molecular weight of 100,000 increased

Oxidation of trans- and cis-1,2-cyclohexanediol by Gluconobacter oxydans - Preparation of (R)- and (S)-2-hydroxycyclohexanone

The enzymatic oxidation of 1,2-cyclohexanediol and related substrates by Gluconobacter oxydans (ATCC 621) was investigated. At low pH, membrane-bound enzymes were active and at high pH, NAD-dependent, soluble enzymes showed activity. Whole bacterial cells were used to catalyze some bioconversions. Racemic trans-1,2-cyclohexanediol was oxidized at pH 3.5 to give (R)-2-hydroxycyclohexanone (96% e.e.

Redefining passivity breakdown of super duplex stainless steel by electrochemical operando synchrotron near surface X-ray analyses

Passivity determines corrosion resistance and stability of highly-alloyed stainless steels, and passivity breakdown is commonly believed to occur at a fixed potential due to formation and dissolution of Cr(VI) species. In this work, the study of a 25Cr–7Ni super duplex stainless steel in 1 M NaCl solution revealed that the passivity breakdown is a continuous degradation progress of the passive fil

Nanoscale imaging of electric pathways in epitaxial graphene nanoribbons

Graphene nanoribbons (GNRs) are considered as major building blocks in future carbon-based electronics. The electronic performance of graphene nanostructures is essentially influenced and determined by their edge termination and their supporting substrate. In particular, semi-conducting, as well as metallic GNRs, can be fabricated by choosing the proper template which is favorable for device archi

Another Primordial Day : the paleo metal diaries

This book contains lavish tales of long dead creatures and reading it may trigger an unexpected consuming impulse for a whole new set of bizarre knowledge and cause a severe addiction to heavy music.

Shielding effects and residual stresses at cleavage due to pre-existing dislocations

The motion of pre-existing edge dislocations in an infinite linear elastic body is studied at initiation of crack growth and at quasi-static steady-state crack growth. Dislocation nucleation is assumed not to occur. Thus, the study concerns only dislocations that are present in the virgin material. A dislocation is assumed to glide if its driving force exceeds a critical value. Changes in dislocat

Surface Classification with Millimeter-Wave Radar Using Temporal Features and Machine Learning

Classification of surfaces using millimeter-wave radar commonly considers the use of polarization-based methods for road condition monitoring. When a surface consists of larger structures, one is instead often interested in monitoring the surface topography, which is typically not resolvable by the limited radar bandwidth. To alleviate this problem, we here consider several phase coherent radar me

Calcium Antagonistic Properties of the Sesquiterpene T‐Cadinol : A Comparison with Nimodipine in the Isolated Rat Aorta

Abstract: (+)‐T‐Cadinol is a sesquiterpene with smooth muscle relaxing properties. In the isolated rat aorta, T‐cadinol relaxed contractions induced by 60 mM K+ in a concentration‐dependent fashion. The dihydropyridine calcium antagonist nimodipine was approximately 4,000 times more potent than T‐cadinol. While both drugs nearly abolished the K+‐induced contractions, they only partially relaxed co