Non-rapid eye movement sleep with low muscle tone as a marker of rapid eye movement sleep regulation

Background  

It was recently reported that epochs of non-REM sleep (NREMS) with low muscle tone represent a partial correlate of REM sleep (REMS). To further investigate this phenomenon, episodes of restricted night-time sleep (23:00 – 03.00h) and subsequent morning sleep (10:00 – 13:00h) were analysed.     

An experimental study on swirling flow in a cylindrical annuli using the PIV technique

Abstract  

An experimental investigation was conducted to study the characteristics of turbulent swirling flow in an axisymmetric annuli. The swirl angle measurements were performed using a flow visualization technique using smoke and dye liquid for Re = 60,000–80,000. Using the two-dimensional particle image velocimetry method, this study found the time-mean velocity distribution and turbulent intensity in water with swirl for Re = 20,000, 30,000, and 40,000 along longitudinal sections. There were neutral points for equal axial velocity at y/(R − r) = 0.7–0.75, and the highest axial velocity was recorded near y/(R − r) = 0.9. Negative axial velocity was observed near the convex tube along X/(D − d) = 3–23.     

Mono and bimetallic nanoparticles of gold,silver and palladium-catalyzed NADH oxidation-coupled reduction of Eosin-Y

Abstract  

Mono metallic (Au, Ag, Pd) and bimetallic (Au–Ag, Ag–Pd, Au–Pd) with 1:1 mol stoichiometry, nanoparticles are synthesized using one-pot, temperature controlled chemical method using cetyltrimethylammonium bromide (CTAB) as the capping agent. The particle sizes (Au = 5.6, Ag = 5.0, Pd = 6.0, Au–Ag = 9.2, Ag–Pd = 9.6, Au–Pd = 9.4 nm) are characterized by UV–Vis, HRTEM, and XRD measurements, respectively. CTAB bindings onto mono and bimetallic nanoparticles are analyzed by FTIR spectra. The catalytic activities of mono and bimetallic nanoparticles are tested on the reaction between NADH oxidation and Eosin-Y reduction. The effects of base, pH, ionic strength, nature of mono and bimetallic catalysts are studied and the reaction conditions are optimized. Bimetallic nanoparticles exhibited better catalysis than the mono metallic nanoparticles, which may be due to the electronic effects of the core to shell metal atoms.     

Preparation and characterization of nickel hydroxide microspheres assembled by nanoribbons

Abstract  

This article describes a facile green strategy for preparing the Ni(OH)₂ microsphere assembled by nanoribbons by the template of the squama inner coat of onion at mild condition. The method is simple and effective. The results of SEM show the products are Ni(OH)₂ microspheres with diameters in the range of 500–2,500 nm. The results of TEM show the microsphere is assembly by nanoribbons, with thickness in the range of 30–50 nm. The products were characterized by powder X-ray diffraction, IR, and thermogravimetric analysis. A possible formation mechanism was also proposed.     

An extremely rich repertoire of bursting patterns during the development of cortical cultures

Background  

We have collected a comprehensive set of multi-unit data on dissociated cortical cultures. Previous studies of the development of the electrical activity of dissociated cultures of cortical neurons each focused on limited aspects of its dynamics, and were often based on small numbers of observed cultures. We followed 58 cultures of different densities – 3000 to 50,000 neurons on areas of 30 to 75 mm² – growing on multi-electrode arrays (MEAs) during the first five weeks of their development.     

Traceless synthesis of diketopiperazine fused tetrahydro-β-carbolines on soluble polymer support

Abstract  

The Pictet–Spengler reaction, using polyethylene glycol immobilized tryptophan ester with a variety of ketones, was achieved by refluxing condition in acidic chloroform. The linear as well as cyclic ketones were employed. All the ketones were reacted within 6–8 h to furnish soluble polymer-supported tetrahydro-β-carboline in good yields. Further expansion at N-terminus of tetrahydro-β-carbolines was achieved through a reaction with chloroacetyl chloride. Finally, the 2,5-diketopiperazine skeleton was constructed over a β-carboline by amination of the resulting N-chloroacetamides and subsequent intramolecular cyclization leading to cleavage of the polymer; constitutes a traceless synthesis of tetracyclic molecular architecture. Significantly, this strategy affords a straightforward and efficient approach for the construction of biological promising molecules with high purity and good yields.     

Quantitative measurement of dynamic flow induced by <Emphasis Type="Italic">Tetrahymena pyriformis</Emphasis> (<Emphasis Type="Italic">T. pyriformis</Emphasis>) using micro-particle image velocimetry

Abstract  

In-depth quantitative visualization studies are required to understand the flow induced by swimming micro-organisms and find potential applications. The present study visualized the flow induced by Tetrahymena pyriformis of size 45–50 μm, which swam freely and via stimulation by galvanotaxis in a PDMS micro-chamber using a micro-particle image velocimetry system. The results showed that the maximum velocity of the induced flow was around 430 μm/s for free swimming and 700 μm/s for galvanotactic-controlled swimming. Due to the applied electric field, the electro-osmosis flow led to increased velocity of roughly 135 μm/s at 3 V/mm. The increased velocity stems from the increased motility of the cell under the electric field. Therefore, it was demonstrated that galvanotaxis can control the swimming direction and increase the induced velocity.     

Neurophysiological correlates of mismatch in lexical access

Background  

In the present study neurophysiological correlates related to mismatching information in lexical access were investigated with a fragment priming paradigm. Event-related brain potentials were recorded for written words following spoken word onsets that either matched (e.g., kan – Kante [Engl. edge]), partially mismatched (e.g., kan – Konto [Engl. account]), or were unrelated (e.g., kan – Zunge [Engl. tongue]). Previous psycholinguistic research postulated the activation of multiple words in the listeners' mental lexicon which compete for recognition. Accordingly, matching words were assumed to be strongly activated competitors, which inhibit less strongly activated partially mismatching words.     

Sonochemical synthesis and application of rhodium–graphene nanocomposite

Abstract  

Highly water dispersible rhodium–graphene nanocomposite have been successfully synthesized by the simple reduction of Rh³⁺ salt on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymer or pluronic-stabilized graphene oxide (GO) nanosheets with borohydride. Rhodium nanoparticles, having average size of 1–3 nm, are homogeneously distributed through out the graphene sheets. Some porous structures of graphene sheets have also been observed after the reduction of pluronic-stabilized GO in the presence of metal ions. The material is very effective for hydrogenation of arenes, especially for benzene as the substrate material at the room temperature and 5 atm pressure of hydrogen.     

Effects of NR1 splicing on NR1/NR3B-type excitatory glycine receptors

Background  

N-methyl-D-aspartate receptors (NMDARs) are the most complex of ionotropic glutamate receptors (iGluRs). Subunits of this subfamily assemble into heteromers, which – depending on the subunit combination – may display very different pharmacological and electrophysiological properties. The least studied members of the NMDAR family, the NR3 subunits, have been reported to assemble with NR1 to form excitatory glycine receptors in heterologous expression systems. The heterogeneity of NMDARs in vivo is in part conferred to the receptors by splicing of the NR1 subunit, especially with regard to proton sensitivity.     

Squalestatin alters the intracellular trafficking of a neurotoxic prion peptide

Background  

Neurotoxic peptides derived from the protease-resistant core of the prion protein are used to model the pathogenesis of prion diseases. The current study characterised the ingestion, internalization and intracellular trafficking of a neurotoxic peptide containing amino acids 105–132 of the murine prion protein (MoPrP105-132) in neuroblastoma cells and primary cortical neurons.     

Microwave microplasma sources based on microstrip-like transmission lines

In this paper, we study two microwave sources based on a planar transmission line configuration, corresponding to linear resonators. In both sources, micro-plasmas are produced within the 50–200 m\mu m gap created between two metal electrodes placed at the open end of a microstrip-like transmission line. The study of the sources follows a complementary approach that uses simulation and experiment. Simulations analyze the electromagnetic behavior of the sources, using the commercial tool CST Microwave Studio^?, and characterize the plasmas produced, using a fluid-type code to describe the dynamics of charged particles. Experimentally, the return loss of the sources (hence their quality factors) is measured without and with plasma. Plasma diagnostics (in air and in argon), based on optical emission spectroscopy measurements, enable to obtain the typical plasma temperatures and the electron density (using Stark broadening measurements of the H_b_{\beta} line-emission profile). Results reveal that the sources have similar quality factors (~15–20), yielding high-density (~10¹⁴ cm^-3)^{-3}), low-power (~10–50 W), non-equilibrium micro-plasmas (with rotational temperatures of ~950–1400 K in air and ~550–630 K in argon, vibrational temperatures of ~5200–5800 K in air and excitation temperatures of ~5800 K in argon), over volumes of ~10^-4–10^-3 cm³.     

Matrix metalloproteinase-7 facilitates immune access to the CNS in experimental autoimmune encephalomyelitis

Background  

Metalloproteinase inhibitors can protect mice against experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). Matrix metalloproteinase-9 (MMP-9) has been implicated, but it is not clear if other MMPs are also involved, including matrilysin/MMP-7 – an enzyme capable of cleaving proteins that are essential for blood brain barrier integrity and immune suppression.     

Functional neural network analysis in frontotemporal dementia and Alzheimer's disease using EEG and graph theory

Background  

Although a large body of knowledge about both brain structure and function has been gathered over the last decades, we still have a poor understanding of their exact relationship. Graph theory provides a method to study the relation between network structure and function, and its application to neuroscientific data is an emerging research field. We investigated topological changes in large-scale functional brain networks in patients with Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD) by means of graph theoretical analysis of resting-state EEG recordings. EEGs of 20 patients with mild to moderate AD, 15 FTLD patients, and 23 non-demented individuals were recorded in an eyes-closed resting-state. The synchronization likelihood (SL), a measure of functional connectivity, was calculated for each sensor pair in 0.5–4 Hz, 4–8 Hz, 8–10 Hz, 10–13 Hz, 13–30 Hz and 30–45 Hz frequency bands. The resulting connectivity matrices were converted to unweighted graphs, whose structure was characterized with several measures: mean clustering coefficient (local connectivity), characteristic path length (global connectivity) and degree correlation (network 'assortativity'). All results were normalized for network size and compared with random control networks.     

Auditory temporal processing in healthy aging: a magnetoencephalographic study

Background  

Impaired speech perception is one of the major sequelae of aging. In addition to peripheral hearing loss, central deficits of auditory processing are supposed to contribute to the deterioration of speech perception in older individuals. To test the hypothesis that auditory temporal processing is compromised in aging, auditory evoked magnetic fields were recorded during stimulation with sequences of 4 rapidly recurring speech sounds in 28 healthy individuals aged 20 – 78 years.     

Iron-doped titanium dioxide nanotubes: a study of electrical,optical, and magnetic properties

Abstract  

Iron doped titanium oxide nanotubes (TNTs) were synthesized by hydrometallurgical process using a mixture of NaOH and methanol as precipitating and reducing agents, respectively. Nanotubes with a high purity and good aspect ratio are produced as indicated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The characterization data show that high-purity Fe-doped TNTs with diameter around 12–14 nm and length around 400–460 nm are synthesized using this process. The TNTs are found to be in the anatase phase and as the Fe doping is increased, the conductivity increases. UV/VIS data suggest the red shift in the peaks and increased absorption on the account of doping. The studies on microcosmic magnetic properties of the sample with 15% Fe content indicate the component of magnetic moment in the axial direction of nanotubes. Doping of Fe is found to considerably affect the crystallite size, Curie temperature (T _c), DC conductivity (σ), and Raman shifts.     

Activation of superior colliculi in humans during visual exploration

Background  

Visual, oculomotor, and – recently – cognitive functions of the superior colliculi (SC) have been documented in detail in non-human primates in the past. Evidence for corresponding functions of the SC in humans is still rare. We examined activity changes in the human tectum and the lateral geniculate nuclei (LGN) in a visual search task using functional magnetic resonance imaging (fMRI) and anatomically defined regions of interest (ROI). Healthy subjects conducted a free visual search task and two voluntary eye movement tasks with and without irrelevant visual distracters. Blood oxygen level dependent (BOLD) signals in the SC were compared to activity in the inferior colliculi (IC) and LGN.     

Immobilization of platinum nanoparticles on 3,4-diaminobenzoyl-functionalized multi-walled carbon nanotube and its electrocatalytic activity

Abstract  

Multi-walled carbon nanotubes (MWCNTs) are functionalized at the sp² C–H defect sites with 3,4-diaminobenzoic acid by a “direct” Friedel–Crafts acylation reaction in a mild polyphosphoric acid/phosphorous pentoxide medium. Owing to enhanced surface polarity, the resulting 3,4-diaminobenzoyl-functionalized MWCNTs (DAB-MWCNT) are highly dispersible in polar solvents, such as ethanol, N-methyl-2-pyrrolidone, and methanesulfonic acid. The absorption and emission properties of DAB-MWCNT in solution state are qualitatively shown to be sensitive to the pH in the environment. The DAB-MWCNT is used as a stable platform on which to deposit platinum nanoparticles (PNP). The PNP/DAB-MWCNT hybrid displays high electrocatalytic activity with good electrochemical stability for an oxygen reduction reaction under an alkaline condition.     

Dynamics of laser-induced bubble collapse visualized by time-resolved optical shadowgraph

Abstract  

Following the first shock wave generation and the successive single bubble expansion after the breakdown by the Nd:YAG laser pulse with 35 mJ and 10 ns in distilled water, the strong secondary shock wave is generated at the instant of the bubble collapse. The single bubble expands up to 0.59 mm in radius, and then closes up by the pressure difference between the ambient liquid pressure at 10² kPa and the vapor pressure inside the bubble at 2 kPa. The maximum pressure up to 3 GPa is attained without the strong rebounding surface motion at about 93 μs after the laser shedding. We present time-resolved velocity measurements for estimating the extreme peak pressures of the first and second shock waves with the Rankine–Hugoniot analysis.     

Flow characteristics around a square cylinder with changing chamfer dimensions

Abstract  

It is known that for a square cylinder subjected to uniform flow, the drag force changes with the angle of attack. To clarify the flow characteristics around a square cylinder with corner cutoffs, we measured the drag coefficient and the Strouhal number for changing chamfer dimensions. We analyzed the flow around a square cylinder with corner cutoffs by applying the RNG k–ε turbulent model, and investigated the surface flow pattern using visualization by means of the oil film and mist flow method. From these results, we obtained the surface flow patterns by the oil film method and numerical analysis. The numerical results agreed well with the experimental values. The drag coefficient of the square cylinder with corner cutoffs decreased suddenly at an angle of attack of about α = 0°– 10° when compared with the drag coefficient for a square cylinder. The minimum value of the drag coefficient for the square cylinder with corner cutoffs decreased by about 30% compared with that for the square cylinder. The drag coefficient of the square cylinder with 10% corner cutoffs was found to be smallest, since the wake area of this square cylinder was smaller compared with that of the other square cylinder.