Origin of Pressure Resistance in Deep-Sea Lactate Dehydrogenase.

High hydrostatic pressure has a dramatic effect on biochemical systems, as exposure to high pressure can result in structural perturbations ranging from dissociation of protein complexes to complete denaturation. The deep ocean presents an interesting paradox since it is teeming with life despite the high-pressure environment. This is due to evolutionary adaptations in deep-sea organisms, such as amino acid substitutions in their proteins, which aid in resisting the denaturing effects of pressure.

Ultrathin ultrastrong transparent films made from regenerated cellulose and epichlorohydrin.

Thin films used in electronic devices are often petroleum-based, non-biodegradable, and non-renewable polymers. Herein, ultrathin ultrastrong regenerated cellulose films were made with a facile method by applying a solution of mildly carboxylated nanocellulose and various amounts of epichlorohydrin (ECH) as a crosslinker. The morphology and physiochemical properties of films were measured using FE-SEM, TEM, FTIR, NMR, UV-Vis, XRD, DLS, and TGA.

Adsorption of Tannic Acid onto Gold Surfaces.

Thin film coatings are widely applicable in materials for consumer products, electronics, optical coatings, and even biomedical applications. Wet coating can be an effective method to obtain thin films of functional materials, and this technique has recently been studied in depth for the formation of bioinspired polyphenolic films. Naturally occurring polyphenols such as tannic acid (TA) have garnered interest due to their roles in biological processes and their applicability as antioxidants, antibacterial agents, and corrosion inhibitors.

Carfentanil structural analogs found in street drugs by paper spray mass spectrometry and their characterization by high-resolution mass spectrometry.

Carfentanil is one of the most potent synthetic opioids ever developed, with an estimated analgesic potency approximately 20-100 times that of fentanyl and 10,000 times that of morphine. Carfentanil has been appearing in the illicit drug supply in many regions and has been linked to fatal overdose events. A subset of 59 street drug samples obtained in Victoria, B.

Molecular Interactions of Tannic Acid with Proteins Associated with SARS-CoV-2 Infectivity.

The overall impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on our society is unprecedented. The identification of small natural ligands that could prevent the entry and/or replication of the coronavirus remains a pertinent approach to fight the coronavirus disease (COVID-19) pandemic. Previously, we showed that the phenolic compounds corilagin and 1,3,6-tri-O-galloyl-β-D-glucose (TGG) inhibit the interaction between the SARS-CoV-2 spike protein receptor binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 target receptor on the cell membrane of the host organism.

Isotope Quantum Effects in the Metallization Transition in Liquid Hydrogen.

Quantum effects in condensed matter normally only occur at low temperatures. Here we show a large quantum effect in high-pressure liquid hydrogen at thousands of Kelvins. We show that the metallization transition in hydrogen is subject to a very large isotope effect, occurring hundreds of degrees lower than the equivalent transition in deuterium.

Understanding high pressure molecular hydrogen with a hierarchical machine-learned potential.

The hydrogen phase diagram has several unusual features which are well reproduced by density functional calculations. Unfortunately, these calculations do not provide good physical insights into why those features occur. Here, we present a fast interatomic potential, which reproduces the molecular hydrogen phases: orientationally disordered Phase I; broken-symmetry Phase II and reentrant melt curve.

Phase behavior of the quantum Lennard-Jones solid.

The Lennard-Jones (LJ) potential is perhaps one of the most widely used models for the interaction of uncharged particles, such as noble gas solids. The phase diagram of the classical LJ solid is known to exhibit transitions between hcp and fcc phases. However, the phase behavior of the quantum LJ solid remains unknown.

Dye Removal Using Hairy Nanocellulose: Experimental and Theoretical Investigations.

Adsorption is a common technique for the treatment of dye-contaminated wastewater. Achieving a high dye removal capacity is a common challenge with sustainable, low-cost adsorbents. Recently, a class of easily functionalized, biorenewable cellulose nanoparticles called hairy nanocellulose has been developed.

Theoretical volume profiles for conformational changes: Application to internal rotation of benzene ring in 1,12-dimethoxy-[12]-paracyclophane.

Identification of the transition state is an important step in the study of reaction kinetics and mechanisms. However, for non-rigid chemical systems where multiple viable reaction pathways may exist, enumeration of all possible transition states quickly becomes computationally expensive, if at all feasible. As an alternative approach, we recently proposed a methodology where the volumetric properties of a flexible reaction system are used to locate its transition state ensemble through a comparison of its theoretically determined volume profile and experimental activation volumes derived from high pressure kinetic data.

YjjQ Represses Transcription of flhDC and Additional Loci in Escherichia coli.

Unlabelled: The presumptive transcriptional regulator YjjQ has been identified as being virulence associated in avian pathogenic Escherichia coli (APEC). In this work, we characterize YjjQ as transcriptional repressor of the flhDC operon, encoding the master regulator of flagellar synthesis, and of additional loci. The latter include gfc (capsule 4 synthesis), ompC (outer membrane porin C), yfiRNB (regulated c-di-GMP synthesis), and loci of poorly defined function (ybhL and ymiA-yciX).

The effect of supervised prenatal exercise on fetal growth: a meta-analysis.

Objective: To estimate the influence of structured prenatal exercise on newborn birth weight, macrosomia, and growth restriction.

Data Sources: A structured search of MEDLINE, EMBASE, CINAHL, Sport Discus, Ovid's All EBM Reviews, and ClinicalTrials.gov databases up to January 13, 2015.

Theoretical volume profiles as a tool for probing transition states: folding kinetics.

The mechanism by which conformational changes, particularly folding and unfolding, occur in proteins and other biopolymers has been widely discussed in the literature. Molecular dynamics (MD) simulations of protein folding present a formidable challenge since these conformational changes occur on a time scale much longer than what can be afforded at the current level of computational technology. Transition state (TS) theory offers a more economic description of kinetic properties of a reaction system by relating them to the properties of the TS, or for flexible systems, the TS ensemble (TSE).

Molecular dynamics calculation of molecular volumes and volumes of activation.

Experimentally, the effects of pressure on reaction rates are described by their pressure derivatives, known as volumes of activation. Transition state theory directly links activation volumes to partial molar volumes of reactants and transition states. We discuss a molecular dynamics method for the accurate calculation of molecular volumes, within which the volumes of molecular species are obtained as a difference between the volumes of pure solvent and solvent with a single molecule inserted.

The challenge of defining normality for human mitral and aortic valves: geometrical and compositional analysis.

Advances in digital imaging technology and in tools for obtaining detailed quantitation of morphological features have facilitated a new approach to pathological assessment of many tissues, including heart valves. In the present study, we quantitatively examined the tissue geometry and composition of structurally normal mitral and aortic valves removed at autopsy or surgery from patients aged 15-84 years. Through univariate analyses of quantitative variables, we have determined which features change distinctively with age.

Inter-laboratory comparison of air particulate monitoring data.

This paper compares three analytical methods that are often used to analyze composition of atmospheric aerosol: Ion Chromatography (IC), Proton Induced X-ray Emission (PIXE), and X-ray Fluorescence (XRF). Three monitoring studies are discussed: (1) a comparison of air particulate data collected by several independent sampler/analytical technique suites run by different laboratories; (2) a study involving two identical samplers and a single suite of analytical techniques; and (3) analysis of identical aerosol samples by two different techniques (XRF vs. PIXE).

Ratio of cut surface area to leaf sample volume for water potential measurements by thermocouple psychrometers.

Evaporative losses from the cut edge of leaf samples are of considerable importance in measurements of leaf water potential using thermocouple psychrometers. The ratio of cut surface area to leaf sample volume (area to volume ratio) has been used to give an estimate of possible effects of evaporative loss in relation to sample size. A wide range of sample sizes with different area to volume ratios has been used.

In situ field measurement of leaf water potential using thermocouple psychrometers.

Thermocouple psychrometers are the only instruments which can measure the in situ water potential of intact leaves, and which can possibly be used to monitor leaf water potential. Unfortunately, their usefulness is limited by a number of difficulties, among them fluctuating temperatures and temperature gradients within the psychrometer, sealing of the psychrometer chamber to the leaf, shading of the leaf by the psychrometer, and resistance to water vapor diffusion by the cuticle when the stomates are closed. Using Citrus jambhiri, we have tested several psychrometer design and operational modifications and showed that in situ psychrometric measurements compared favorably with simultaneous Scholander pressure chamber measurements on neighboring leaves when the latter were corrected for the osmotic potential.

A Rapid Psychrometric Procedure for Water Activity Measurement of Foods in the Intermediate Moisture Range .

Commercial vapor pressure thermocouple psychrometers (hygrometers) are now generally accepted for measuring water activity, a (water potential) in plants and soils, and commercial instruments are available. We have adapted them for a measurements in the 0.99 to 0.

Measuring water potential (activity) from free water to oven dryness.

Water activities (potentials) in plant materials were measured over the range from free water to oven dryness with a Spanner thermocouple psychrometer. In a two-step procedure, water was first condensed on the thermocouple junction for several minutes. The sample was then inserted under the wet thermocouple and the maximum psychrometric cooling was measured in about 10 seconds.

Reversible blockade of myelinated and non-myelinated cardiac afferents in cats by instillation of procaine into the pericardium.

Pericardial local anaesthesia was instituted in 33 chloralosed cats through catheters implanted into the pericardium. The activity of 1531 single fibres teased from either vagus in the neck was identified and classified according to source. Random testing with 2% procaine instilled into the pericardium revealed that only cardiac afferents could be blocked.

Immediate and late ventillatory response to high and low O2 in preterm infants and adult subjects.

The differences in the immediate (30 sec or 1 min) and late (5 min) ventilatory response to high and low O2 have not been quantitated in preterm infants and adult subjects using the same methods. It was thought that these differences might explain the paradoxical ventilatory response to CO2 at various O2 concentrations in preterm infants (12). Thus, 9 preterm infants and 10 adult subjects were given 21% O2 to breathe and then 100 or 15% O2 for 5 min each.

Maternal and neonatal effects of methoxyflurane, nitrous oxide and lumbar epidural anaesthesia for Caesarean section.

General anaesthetic techniques continue to be used for Caesarean section despite the possible increased incidence of foetal acidosis and neonatal depression. Two techniques of general anaesthesia (methoxyflurane-oxygen and nitrous oxide-oxygen) and lumbar epidural anaesthesia were compared in 37 patients under-going elective Caesarean section. Apgar scores at birth were similar in all three groups.