Sleep in the lesser mouse-deer (Tragulus kanchil)

The mouse-deer or chevrotains are the smallest of the ungulates and ruminants. They are characterized by a number of traits which are considered plesiomorphic for the Artiodactyla order. The objective of this study was to examine sleep in the lesser mouse-deer (Tragulus kanchil), which is the smallest in this group (body mass < 2.2 kg). Electroencephalogram, nuchal electromyogram, electrooculogram, and body acceleration were recorded in four adult mouse-deer females using a telemetry system in Bu Gia Map National Park in Vietnam. The mouse-deer spent on average 49.7 ± 3.0% of 24 h in non-rapid eye movement (NREM) sleep. REM sleep occupied 1.7 ± 0.3% of 24 h or 3.2 ± 0.5% of total sleep time. The average duration of REM sleep episodes was 2.0 ± 0.2 min, the average maximum was 5.1 ± 1.1 min, and the longest episodes lasted 8 min. NREM sleep occurred in sternal recumbency with the head held above the ground while 64.7 ± 6.4% of REM sleep occurred with the head resting on the ground. The eyes were open throughout most of the NREM sleep period. The mouse-deer displayed polyphasic sleep and crepuscular peaks in activity (04:00–06:00 and 18:00–19:00). The largest amounts of NREM occurred in the morning (06:00–09:00) and the smallest before dusk (at 04:00–06:00). REM sleep occurred throughout most of the daylight hours (08:00–16:00) and in the first half of the night (19:00–02:00). We suggest that the pattern and timing of sleep in the lesser mouse-deer is adapted to the survival of a small herbivorous animal, subject to predation, living in high environmental temperatures in the tropical forest undergrowth.     

Histological characterization of age‐related skin changes following the use of picosecond laser: Low vs high energy

Fractional lasers have become widespread in dermatology owing to their efficacy and safety. Comparative analysis of histological features after laser rejuvenation using a 1064‐nm fractionated handpiece picosecond laser with different energy fluence levels (1.1 or 2.1 J/cm²). An open‐label, study of 28 women aged 36 to 60 years with signs of age‐related photodamage and skin changes of the face and neck was conducted using a fractional picosecond 1064 nm laser in low vs high fluence. The clinical assessment at 3 weeks showed more pronounced effect on facial skin rejuvenation with the higher fluence of 2.1 J/cm² compared to 1.1 J/cm². The effect and safety of laser rejuvenation using a picosecond laser has been shown with more pronounced histological effects at higher fluences.     

Li-based layered nickel–tin oxide obtained through electrochemically-driven cation exchange

The Li-based layered nickel-tin oxide Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ has been synthesized via electrochemically-driven Li⁺ for Na⁺ exchange in O3-NaNi_0.5Sn_0.5O₂. The crystal structure of Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ was Rietveld-refined from powder X-ray diffraction data (a = 3.03431(7) Å, c = 14.7491(8) Å, S. G. R$\bar{3}$m). It preserves the O3 stacking sequence of the parent compound, but with ∼13% lower unit cell volume. Electron diffraction and atomic-resolution scanning transmission electron microscopy imaging revealed short-range Ni/Sn ordering in both the pristine and Li-exchanged materials that is similar to the “honeycomb” Li/M ordering in Li₂MO₃ oxides. As supported by bond-valence sum and density functional theory calculations, this ordering is driven by charge difference between Ni²⁺ and Sn⁴⁺ and the necessity to maintain balanced bonding for the oxygen anions. Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ demonstrates reversible electrochemical (de)intercalation of ∼0.21 Li⁺ in the 2.8–4.3 V vs. Li/Li⁺ potential range. Limited electrochemical activity is attributed to a formation of the surface Li/Ni disordered rock-salt barrier layer as the Li⁺ for Na⁺ exchange drastically reduces the energy barrier for the Li/Ni antisite disorder.

Layered O3-Li_0.35Na_0.07Ni_0.5Sn_0.5O₂ cathode material was obtained by electrochemically-driven Li for Na exchange. The exchange process was comprehensively studied via a combination of transmission electron microscopy techniques.     

Electrochemical Improvement of the MWCNT/Al Electrodes for Supercapacitors

An original technique of chemical deposition (CVD) by catalytic pyrolysis of ethanol vapor was used to directly grow multiwall carbon nanotubes (MWCNTs) layers on aluminum foil. The grown nanotubes had excellent adhesion and direct electrical contact to the aluminum substrate. This material was perfect for use in electrochemical supercapacitors. In this work, the possibility of a significant increase in the specific capacity of MWCNTs by simple electrochemical oxidation was investigated. The optimal conditions for improving the characteristics of the MWCNT/Al electrodes were found. Electrochemical treatment of MWCNT/Al electrodes in a 0.005 M Na₂SO₄ solution at a potential of 4–5 V for 20–30 min increased the specific capacity of MWCNTs from 30 F/g to 140 F/g. The properties of modified nanotubes were investigated by X-ray photoelectron spectroscopy, cyclic voltammetry (CV), and impedance spectroscopy. A significant increase in the concentration of oxygen-containing functional groups on the surface of MWCNTs was found as a result of electrochemical oxidation. The modified MWCNT/Al electrodes maintained excellent stability to multiple charge–discharge cycles. After 20,000 CVs, the capacity loss was less than 5%. Thus, the results obtained significantly expanded the possibilities of using MWCNT/Al composite materials obtained by the method of direct deposition of carbon nanotubes on aluminum foil as electrodes for supercapacitors.     

Molecular mechanisms of translation initiation in eukaryotes

Translation initiation is a complex process in which initiator tRNA, 40S, and 60S ribosomal subunits are assembled by eukaryotic initiation factors (eIFs) into an 80S ribosome at the initiation codon of mRNA. The cap-binding complex eIF4F and the factors eIF4A and eIF4B are required for binding of 43S complexes (comprising a 40S subunit, eIF2/GTP/Met-tRNAi and eIF3) to the 5' end of capped mRNA but are not sufficient to promote ribosomal scanning to the initiation codon. eIF1A enhances the ability of eIF1 to dissociate aberrantly assembled complexes from mRNA, and these factors synergistically mediate 48S complex assembly at the initiation codon. Joining of 48S complexes to 60S subunits to form 80S ribosomes requires eIF5B, which has an essential ribosome-dependent GTPase activity and hydrolysis of eIF2-bound GTP induced by eIF5. Initiation on a few mRNAs is cap-independent and occurs instead by internal ribosomal entry. Encephalomyocarditis virus (EMCV) and hepatitis C virus epitomize distinct mechanisms of internal ribosomal entry site (IRES)-mediated initiation. The eIF4A and eIF4G subunits of eIF4F bind immediately upstream of the EMCV initiation codon and promote binding of 43S complexes. EMCV initiation does not involve scanning and does not require eIF1, eIF1A, and the eIF4E subunit of eIF4F. Initiation on some EMCV-like IRESs requires additional noncanonical initiation factors, which alter IRES conformation and promote binding of eIF4A/4G. Initiation on the hepatitis C virus IRES is even simpler: 43S complexes containing only eIF2 and eIF3 bind directly to the initiation codon as a result of specific interaction of the IRES and the 40S subunit.     

A three-dimensional weighted cone beam filtered backprojection (CB-FBP) algorithm for image reconstruction in volumetric CT under a circular source trajectory

The original FDK algorithm proposed for cone beam (CB) image reconstruction under a circular source trajectory has been extensively employed in medical and industrial imaging applications. With increasing cone angle, CB artefacts in images reconstructed by the original FDK algorithm deteriorate, since the circular trajectory does not satisfy the so-called data sufficiency condition (DSC). A few 'circular plus' trajectories have been proposed in the past to help the original FDK algorithm to reduce CB artefacts by meeting the DSC. However, the circular trajectory has distinct advantages over other scanning trajectories in practical CT imaging, such as head imaging, breast imaging, cardiac, vascular and perfusion applications. In addition to looking into the DSC, another insight into the CB artefacts existing in the original FDK algorithm is the inconsistency between conjugate rays that are 180 degrees apart in view angle (namely conjugate ray inconsistency). The conjugate ray inconsistency is pixel dependent, varying dramatically over pixels within the image plane to be reconstructed. However, the original FDK algorithm treats all conjugate rays equally, resulting in CB artefacts that can be avoided if appropriate weighting strategies are exercised. Along with an experimental evaluation and verification, a three-dimensional (3D) weighted axial cone beam filtered backprojection (CB-FBP) algorithm is proposed in this paper for image reconstruction in volumetric CT under a circular source trajectory. Without extra trajectories supplemental to the circular trajectory, the proposed algorithm applies 3D weighting on projection data before 3D backprojection to reduce conjugate ray inconsistency by suppressing the contribution from one of the conjugate rays with a larger cone angle. Furthermore, the 3D weighting is dependent on the distance between the reconstruction plane and the central plane determined by the circular trajectory. The proposed 3D weighted axial CB-FBP algorithm can be implemented in either the native CB geometry or the so-called cone-parallel geometry. By taking the cone-parallel geometry as an example, the experimental evaluation shows that, up to a moderate cone angle corresponding to a detector dimension of 64 x 0.625 mm, the CB artefacts can be substantially suppressed by the proposed algorithm, while advantages of the original FDK algorithm, such as the filtered backprojection algorithm structure, 1D ramp filtering and data manipulation efficiency, are maintained.