Search results for "Bridge"
showing 10 items of 355 documents
Charge Pair Interactions in Transmembrane Helices and Turn Propensity of the Connecting Sequence Promote Helical Hairpin Insertion
2013
alpha-Helical hairpins, consisting of a pair of closely spaced transmembrane (TM) helices that are connected by a short interfacial turn, are the simplest structural motifs found in multi-spanning membrane proteins. In naturally occurring hairpins, the presence of polar residues is common and predicted to complicate membrane insertion. We postulate that the pre-packing process offsets any energetic cost of allocating polar and charged residues within the hydrophobic environment of biological membranes. Consistent with this idea, we provide here experimental evidence demonstrating that helical hairpin insertion into biological membranes can be driven by electrostatic interactions between clo…
Abyssomicin E, a highly functionalized polycyclic metabolite from Streptomyces species.
2007
Abyssomicin E (1), a new polycyclic metabolite with a C19 skeleton, was isolated from Streptomyces sp. (HKI0381). Its chemical structure was determined by comprehensive NMR and MS spectroscopic analyses. For the first time in this recently discovered class of compounds, the absolute stereochemistry was directly established by subsequent single-crystal X-ray diffraction study using anomalous dispersion with copper radiation.
The essential oil of turpentine and its major volatile fraction (alpha- and beta-pinenes): a review.
2010
This paper provides a summary review of the major biological features concerning the essential oil of turpentine, its origin and use in traditional and modern medicine. More precisely, the safety of this volatile fraction to human health, and the medical, biological and environmental effects of the two major compounds of this fraction (alpha- and beta-pinenes) have been discussed.
Quasi‐digital front‐ends for current measurement in integrated circuits with giant magnetoresistance technology
2014
In this study, the authors report on two different electronic interfaces for low-power integrated circuits electric current monitoring through current-to-frequency (I-f) conversion schemes. This proposal displays the intrinsic advantages of the quasi-digital systems regarding direct interfacing and self-calibrating capabilities. In addition, as current-sensing devices, they have made use of the giant magnetoresistance (GMR) technology because of its high sensitivity and compatibility with standard complementary metal oxide semiconductor processes. Single elements and Wheatstone bridges based on spin-valves and magnetic tunnel junctions have been considered. In this sense, schematic-level si…
Hydration and water holding properties of cross-linked lignite humic acids
2014
Abstract Lignite and lignite humic acids, which are used as soil amendments sometimes, are supposed to improve soil properties such as water holding capacity. The structure of those materials is composed of various organic molecules stabilized mostly by weak interactions. Therefore, excess of water causes only partial swelling, but most of the physical structure is destabilized. This accelerates the desiccation and hampers their application as natural hydrogel-like substances. In order to stabilize the structure of lignite humic acids and improve the water holding capacity, we applied formaldehyde cross-linking procedure based on covalent coupling of aromatic humic acids moieties. By combin…
Old Principle of Liquid Ion-Impedance Spectrometry (Particularly in Milk) Realised by New Components
2020
Abstract Ion impedance spectrometry enables detection of the concentrations of multiple chemical compositions in a weak solution, usually if only part of a complex signal is used and the frequency is not swept. Prior to the method described in this paper, ion impedance required rather sophisticated electronics to collect the results from an instrument, as well as the electrode polarisation minimising. We elaborated and tested circuitry that uses the newest electronics components for a chemical analysis instrument designed according to a principle patented in Latvia (No. SU-1021440A), year 1981. The newly improved ion impedance spectrometry apparatus is suited for accurate measurement of ion…
Myocardial bridge pathology and preventable accidents during physical activity of healthy subjects: A case report and a literature review.
2020
Myocardial bridging is a congenital coronary pathology described as a segment of coronary artery which courses through the myocardial wall under the muscle bridge. Although the prognosis of myocardial bridging is benign, sports medicine recognises myocardial bridging as a leading cause of sudden death among young basketball, football and soccer players. The authors report a case of a 42-year-old man who collapsed while playing football. He died notwithstanding prompt medical assistance and cardiopulmonary resuscitation. At autopsy, gross examination of the heart revealed the intramural course of the left anterior descending coronary artery to be 2 cm from its coronary ostial origin. Histol…
Using FFR to Detect Ischemia in Myocardial Bridge Lesions
2016
Beyond atherosclerosis, a number of other phenomena may result in cardiac ischemia. Among these, extracoronary compression due to myocardial bridges may cause a dynamic stenosis and typical angina. The assessment of the hemodynamic relevance and the treatment of such lesions have unique characteristics that are due to the fact that extracoronary compression from myocardial bridges is mostly a systolic phenomenon and is dependent on the inotropic state. The consequence is that other hyperemic stimuli, such as dobutamine, may be more adequate to unveil ischemia in these settings.
Coronary Artery Shape and Flow Changes Induced by Myocardial Bridging.
1993
Changes in coronary shape and blood flow induced by myocardial bridging were analyzed in a 56-year-old patient with symptoms of unstable angina after the exclusion of other heart disease. Coronary angiography demonstrated a 1.8-cm long myocardial bridge in the middle part of the left anterior descending coronary artery. In systole, an eccentric compression of the artery occurred, resulting in a stenosis that occupied 86% of the diameter and 96% of the area. Intraluminal ultrasound was performed with a 20-MHz transducer in a 4.8-Fr catheter sheath (Boston Scientific Corp.) connected to an ultrasound console (Diasonics Inc.). A side saddle catheter was introduced into the left anterior descen…
Electrical network of nanofluidic diodes in electrolyte solutions: Connectivity and coupling to electronic elements
2016
[EN] We consider a nanopore network with simple connectivity, demonstrating a two-dimensional circuit (full-wave rectifier) with ensembles of conical pores acting as nanofluidic diodes. When the bridge nanopore network is fed with an input potential signal of fluctuating polarity, a fixed output polarity is obtained. The full-wave rectification characteristics are demonstrated with square, sinusoidal, and white noise input waveforms. The charging of a load capacitor located between the two legs of the bridge demonstrates that the nanofluidic network is effectively coupled to this electronic element. These results can be relevant for energy transduction and storage procedures with nanopores …