The base‐pairing properties of 5‐mercuricytosine have been explored at the monomer level by NMR titrations and at the oligonucleotide level by melting temperature measurements. The NMR studies ...revealed a relatively high affinity for guanine, hypoxanthine, and uridine, that is, bases that are deprotonated upon coordination of HgII. Within an oligonucleotide duplex, 5‐mercuricytosine formed HgII‐mediated base pairs with thymine and guanine. In the former case, the duplex formed was as stable as the respective duplex comprising solely Watson–Crick base pairs. Based on detailed thermodynamic analysis of the melting curves, the stabilization by the HgII‐mediated base pairs may be attributed to a comparatively low entropic penalty of hybridization.
Ianus et Mercurius: 5‐Mercuricytosine forms HgII‐mediated base pairs with thymine and guanine (see graphic). The contribution of the former to the melting temperature of a double‐helical oligonucleotide is similar to that of a Watson–Crick base pair. Both of the HgII‐mediated base pairs are characterized by a relatively low entropic penalty of formation.
The rational design of stable, inexpensive catalysts with excellent hydrogen dynamics and sorption characteristics under realistic environments for reversible hydrogen storage remains a great ...challenge. Here, we present a simple and scalable strategy to fabricate a monodispersed, air-stable, magnesium hydride embedded in three-dimensional activated carbon with periodic synchronization of transition metals (MHCH). The high surface area, homogeneous distribution of MgH
nanoparticles, excellent thermal stability, high energy density, steric confinement by carbon, and robust architecture of the catalyst resulted in a noticeable enhancement of the hydrogen storage performance. The resulting MHCH-5 exhibited outstanding hydrogen storage performance, better than that of most reported Mg-based hydrides, with a high storage density of 6.63 wt% H
, a rapid kinetics loading in <5 min at 180 °C, superior reversibility, and excellent long-term cycling stability over ∼435 h. The significant reduction of the enthalpy and activation energy observed in the MHCH-5 demonstrated enhancement of the kinetics of de-/hydrogenation compared to that of commercial MgH
. The origin of the intrinsic hydrogen thermodynamics was elucidated via solid state
H NMR. This work presents a readily scaled-up strategy towards the design of realistic catalysts with superior functionality and stability for applications in reversible hydrogen storage, lithium ion batteries, and fuel cells.
► Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique. ► ZnO nanorods thin films showed much better sensitivity and stability ...than the conventional materials to H2S gas (100ppm) at 50°C. ► This ZnO thin film has potential in application of room temperature H2S gas sensing.
Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique (SPT). The equal amount of methanol and water is used as a solvent to dissolve the AR grade Zinc acetate for precursor solution. This solution is sprayed on to the glass substrate heated at 350°C. The films were characterized by ultra-violet spectroscopy (UV), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The deposition of thin films results in a layer comprising well-shaped hexagonal ZnO nanorods with diameter of 90–120nm and length of up to 200nm. The gas sensing properties of these films have been investigated for various interfering gases such as CO2, CO, ethanol, NH3 and H2S, etc. at operating temperature from 30° (room temperature) to 450°C. The results indicate that the ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H2S gas (100ppm) at 50°C. The hexagonal pillar shaped ZnO nanorods can improve the sensitivity and selectivity of the sensors.
Guidelines are presented for safe practice in the use of intravenous drug infusions for general anaesthesia. When maintenance of general anaesthesia is by intravenous infusion, this is referred to as ...total intravenous anaesthesia. Although total intravenous anaesthesia has advantages for some patients, the commonest technique used for maintenance of anaesthesia in the UK and Ireland remains the administration of an inhaled volatile anaesthetic. However, the use of an inhalational technique is sometimes not possible, and in some situations, inhalational anaesthesia is contraindicated. Therefore, all anaesthetists should be able to deliver total intravenous anaesthesia competently and safely. For the purposes of simplicity, these guidelines will use the term total intravenous anaesthesia but also encompass techniques involving a combination of intravenous infusion and inhalational anaesthesia. This document is intended as a guideline for safe practice when total intravenous anaesthesia is being used, and not as a review of the pros and cons of total intravenous anaesthesia vs. inhalational anaesthesia in situations where both techniques are possible.
While young muscle is capable of restoring the original architecture of damaged myofibers, aged muscle displays a markedly reduced regeneration. We show that expression of the "anti-aging" protein, ...α-Klotho, is up-regulated within young injured muscle as a result of transient Klotho promoter demethylation. However, epigenetic control of the Klotho promoter is lost with aging. Genetic inhibition of α-Klotho in vivo disrupted muscle progenitor cell (MPC) lineage progression and impaired myofiber regeneration, revealing a critical role for α-Klotho in the regenerative cascade. Genetic silencing of Klotho in young MPCs drove mitochondrial DNA (mtDNA) damage and decreased cellular bioenergetics. Conversely, supplementation with α-Klotho restored mtDNA integrity and bioenergetics of aged MPCs to youthful levels in vitro and enhanced functional regeneration of aged muscle in vivo in a temporally-dependent manner. These studies identify a role for α-Klotho in the regulation of MPC mitochondrial function and implicate α-Klotho declines as a driver of impaired muscle regeneration with age.
Dysprosium doped Ni0.8Co0.2Fe2-xDyxO4 ferrite is prepared by simple ceramic method with x varied from 0 to 0.1 in step of 0.025. The influence of Dy doping on structural, morphological, electrical ...and magnetic properties were studied. The formation of ferrite phase was confirmed by X-ray diffraction, which is a characteristic of the spinel ferrite. Increase in average crystallite and grain size has been observed with increase in Dy doping. Prepared samples show the usual dielectric dispersion having Maxwell–Wagner-type interfacial polarization. Reduction in dielectric constant, loss tangent and ac conductivity has been observed with frequency. Room temperature complex impedance analysis shows semicircles attributed to the high resistance values at lower frequencies. Magnetic properties have been studied by measuring M–H plots.
► Preparation of Dy doped Ni–Co ferrite by ceramic method. ► Effect of Dy doping in to Ni–Co substitutional ferrite. ► Structural, electrical and impedance properties of Dy doped Ni–Co ferrite. ► Room temperature magnetic properties of Dy doped Ni–Co ferrite.
► Synthesis of CZTS thin films by PLD. ► Effect of stoichiometry, its deviation on the physical properties. ► Improvement in conversion efficiency using CZTS absorber layer.
The performance of CZTS ...thin films deposited by using pulsed laser deposition technique is investigated as a function of target composition. The chemical composition ratio a=Cu/(Zn+Sn) of the target material has been varied from 0.8 to 1.2 in step of 0.1 by keeping Zn/Sn constant. The effect of the chemical composition in the precursor thin films on the structural, morphological, chemical and optical properties of the CZTS thin films has been investigated. X-ray diffraction and X-ray photoelectron spectroscopy studies showed that the annealed CZTS thin films are of a single kesterite crystal structure without any other secondary phases. The direct band gap energy of the CZTS thin films is found to decrease from 1.72–1.53eV with increase of ‘a’. The estimated band-gap energy from the quantum efficiency measurements is about 1.54eV. The solar cell fabricated with Glass/Mo/CZTS/CdS/ZnO:Al/Al structure grown using a=Cu/(Zn+Sn)=1.1 showed the best conversion efficiency of 4.13% with Voc=700mV, Jsc=10.01mA/cm2 and FF=0.59.
Background
The last two decades have seen a growing trend toward the use of inflatable membranes for spaceborne structures. The spaceborne inflatable membrane structures are the promising solution ...for the compact and lightweight reflector antenna. The inflation technique is used for pressurizing the inflatable membrane structure once the satellite reaches to its predefined orbit.
Objective
The objective of the study is to demonstrate the use of the residue gas inflation technique for the complete deployment of the inflatable thin membrane boom with different folding patterns. The study also aims to find out generalized relation to calculate the safe mass of residue gases to be kept inside spaceborne membrane boom.
Method
The novel analytical relation for the safe mass of residue gases that can be carried for any size of the inflatable boom is established. A comparative study is performed to investigate the effect of variation in a folding pattern on the proposed inflation technique. Experimental, numerical, and analytical approaches were employed for the proposed study.
Result
The results show that the total inflation time is inversely proportional to the mass of the residue gases. Through the comparative study, it has been observed that the change in the inflation time is negligible for different folding patterns with the same mass of residue gas. The result confirms that the safe mass of residue gas is successfully deploying the inflatable boom in the vacuum environmental condition keeping the stresses in the boom in the tolerance limit.
Conclusions
The findings of this research provide insights into a simple and cost-effective design solution for the inflation system along with safe mass of the residue gases which can be used for any size of spaceborne inflatable boom.
► Fabrication of photoconductive UV detector by using spray pyrolysis. ► Photoconductive UV detector based on Ga-doped ZnO thin films having MSM configuration. ►
I–
V characteristic, spectral and ...transient response of Ga-doped ZnO photodetector. ► Highest responsivity of about 1125
A/W at 5
V bias.
High-quality ultraviolet photoconductive detectors have been fabricated using Ga-doped zinc oxide layers grown by spray pyrolysis on glass substrates. The performance of the photoconductivity has been tested by the measurements of the current–voltage (
I–
V) characteristics under forward and reverse bias. The devices have been characterized to investigate the effect of buffer layer on the detector performances. The behaviour of photocurrent with respect to optical power density, wavelength and chopping time has been investigated. We achieved the highest responsivity of about 1125
A/W at 5
V bias at 365
nm peak wavelength. Our approach provides a simple and cost-effective way to fabricate high-performance ‘visible-blind’ UV detectors.
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