Search

This article presents a β-SiC nanopowder synthesis process based on the combustion of a Na2CO3–kSi solid system (k indicates the moles of Si) in an Ar atmosphere. The authors of this study monitored the combustion parameters (temperature and wave velocity), reaction phases, and morphological changes as the Si/Na2CO3 molar ratio was increased. The combustion reaction produced temperatures of 1235–1550°C and resulted in the formation of either carbon nanosheets (k = 1) or SiC nanopowder (k = 2–5) and sodium metasilicate (Na2SiO3) as by-product. The SiC nanopowder was tested for its suitability as an anode material for high-performance rechargeable Li-ion batteries. As a result, good battery performance was obtained, with 407 mAh g–1 at the 5th cycle and 400 mAh g–1 at the 60th cycle, at a capacity retention of approximately 98%.

This study focuses on index-based flood risk assessment in Metro Manila, the capital region of the Philippines and most densely populated region in the country. Its objective is to properly address urban characteristics in flood risk assessment by introducing a specific urban-type set of physical, social, economic and ecological indicators. Analytical hierarchy process (AHP) was used to quantify the optimal selection weights for each of the selected 14 indicators. Five levels of flood risk will be presented in spatial maps using geographic information system (GIS) ranging from Very Low Risk to Very High Risk. Results of this study are expected to aid in understanding flood hazard and risk in Metro Manila. Moreover, the resulting flood risk information can be used as a decision tool in policy making, land-use planning, developing guidelines and countermeasures and flood disaster insurance.

The aim of this study was to elucidate the effect of Myagropsis myagroides extract on tyrosinase activity. Inhibition of tyrosinase was observed in the presence of an n-hexane fraction of Myagropsis myagroides. Separation of the n-hexane fraction using silica gel column chromatography yielded the chloroform:methanol (50:1) fraction, which showed the highest tyrosinase inhibitory activity. After several separation and purification steps, sargachromanol G, sargachromanol I, and mojabanchromanol b were obtained. These 3 chromene compounds displayed strong tyrosinase inhibitory activity. It could be concluded that Myagropsis myagroides is a potential source of natural antimelagenic compounds.

The present study investigated the free radical scavenging activity and antiwrinkle properties of methanol extract, hexane, chloroform, ethyl acetate, and butanol partition fractions of Myagropsis myagroides. The methanol extract showed higher free radical scavenging (65.46 % at 0.5 mg/ml) and collagenase inhibitory activity (29.64 % at 1000 μg/ml) than the water extract (16.68 % at 0.5 mg/ml and < 5 % at 1000 μg/ml). The hexane fraction exhibited strong free radical scavenging activity (96.36 % at 0.5 mg/ml) and collagenase inhibitory activity (IC50 of 712.21 μg/ml). The hexane fraction was subjected to silica gel column chromatography, Sephadex LH-20 column chromatography, octadecyl silica Sepak cartridge, and preparative high performance liquid chromatography. Sargachromaol I was isolated, which showed strong free radical scavenging activity (95.82 % at 0.1 mg/ml) and collagenase inhibitory activity (IC50 value of 54.01 μg/ml). The potential value in preventing skin aging could be confirmed through effects of extract from Myagropsis myagroides on free radical scavenging activity and collagenase inhibitory properties.

Calcium (Ca^(2+))-activated chloride channel accessories (CLCAs) are putative anion channel-related proteins with diverse physiological functions. Exploring CLCA diversity is important for prediction of gene structure and function. In an effort to identify novel CLCA genes in Xenopus laevis, we successfully cloned and characterized a Xenopus laevis cDNA predicted to encode the xCLCA3 gene. Cloning of xCLCA3 was achieved by computational analysis, rapid amplification of cDNA ends (RACE), and a tissue distribution analysis by semi-quantitative reverse transcription (RT) PCR or real-time PCR. We obtained a 2958 bp xCLCA3 cDNA sequence with an open reading frame encoding 943 amino acids. According to the primary structure analysis, xCLCA3 contains a predicted signal sequence, multiple sites of N-linked (N-) glycosylation, N-myristoylation, PKA, PKC, and casein kinase II phosphorylation sites, five putative hydrophobic segments, and the HExxH metalloprotease motif. Additionally, the transmembrane prediction server yielded a preserved N-terminal CLCA domain and a von Willebrand factor type A domain with one transmembrane domain in the C-terminal region. Expression analysis showed that xCLCA3 is expressed in a number of tissues, with strong expression in the brain, colon, small intestine, lung, kidney, and spleen, and poor expression in the heart and liver. These results suggest that xCLCA3 may be a candidate CLCA family member as well as a metalloprotease, rather than just an ion channel accessory protein.

The purpose of this study was to determine the optimum bolus dose of propofol required to provide excellent conditions for tracheal intubation following inhalational induction of anaesthesia using 5% sevoflurane without neuromuscular blockade. Twenty-eight children, aged three to seven years, requiring anaesthesia for short duration surgery were recruited. Two minutes after beginning the inhalational induction with 5% sevoflurane and 60% nitrous oxide, a predetermined dose of propofol was injected over 10 seconds. Propofol dose was determined using the Dixon's up-and-down method, starting from 3 mg/kg (0.5 mg/kg as a step size). Laryngoscopy was performed 50 seconds after propofol injection. The optimum dose of propofol required for excellent intubating conditions was 1.39±0.37 mg/kg in 50% of children during inhalation induction using 5% sevoflurane and 60% nitrous oxide in the absence of neuromuscular blocking agents. From probit analysis, the 95% effective dose of propofol was 2.33 mg/kg (95% confidence interval 1.78 to 6.21 mg/kg).

The Advanced Spent Conditioning Process (ACP) developed by the KAERI is based on pyrometallurgy and the electrolytic reduction plays a central role in transforming spent oxide fuels into metals. The constituents of the spent fuels are distributed between a salt and a reduced metal phase during electrolysis. Lithium metal is produced in a molten LiCl-Li2O cell and then it reacts with the metal oxides of the spent fuel producing Li2O and reduced metals. By focusing on the activity of Li2O and the electric potential, the electrolytic reduction process of the ACP is discussed. Thermodynamic considerations are defined and operation conditions are proposed including Li2O activity and cell potential.

Background: Central sensitization of neuropathic pain is associated with an influx of extracellular calcium via the opening of N-methyl-d-aspartate (NMDA) receptor-gated ion channels, which are usually blocked by magnesium plugs. As magnesium-deficient rats develop a mechanical hyperalgesia and intrathecal or intraperitoneal magnesium suppresses neuropathic pain, the magnesium concentrations in serum and cerebrospinal fluid may be altered in neuropathic pain. We therefore compared the magnesium concentrations in serum and cerebrospinal fluid of neuropathic rats with those in injured rats without symptoms of neuropathic pain and normal rats. Methods: Mechanical allodynia was induced in male Sprague-Dawley rats by tight ligature of the left lumbar fifth and sixth spinal nerves. The threshold of paw withdrawal was evaluated by the up–down method using withdrawal response to stimulus with a von Frey filament on the third, seventh and 14th days. Rats with a threshold of less than 4 g were selected as the symptomatic group and compared with an asymptomatic group, an unoperated control group and a sham-operated group. On the 16th day, the Mg2+ concentrations in serum and cerebrospinal fluid were measured. Results: The magnesium concentrations in the serum and cerebrospinal fluid of symptomatic neuropathic rats did not differ from those in the injured rats without symptoms of neuropathic pain, sham-operated rats and normal rats. Conclusion: Our results suggest that physiologic homeostasis is maintained by active transport through the blood–brain barrier despite the activation of NMDA receptor-gated ion channels. However, rats with neuropathic pain may be in a magnesium-deficient condition at the effector site, such that magnesium treatment can decrease neuropathic pain.

Gamma-ray bursts (GRBs) are the most luminous transient events with short intense flashes thath have been detected in random directions in the sky once or twice per day. Their durations have been measured in seconds, especially short GRBs with duration of

We describe the isolation of a new type of RecQ homologue in Drosophila melanogaster, RECQE. The Recqe gene consists of five exons and four introns, and encodes a protein of 1058 amino acids with a predicted molecular weight of 120,000 Da. The RECQE protein has seven helicase motifs. The helicase domain shows 42% identity overall to that of Escherichia coli RecQ DNA helicase, and is most closely related to Homo sapiens RecQL5 and Caenorhabditis elegans E03A3.2. The C-terminal region of RECQE protein is unique and the longest known among members of the RecQ superfamily. We demonstrate that the RECQE protein has DNA helicase activity and that the C-terminal region is dispensable for this activity. The RECQE mRNA accumulates in oocytes and is expressed at high levels in early embryos. We show for the first time that the expression of a RecQ homologue is developmentally regulated in embryos. These data suggest that the DNA helicase activity of RECQE might be involved in the DNA metabolism of early embryos.

Structural and optical properties of various shapes of quantum wells (QWs), including rectangular, triangular, trapezoidal, and polygonal ones are investigated. Photoluminescence (PL) measurements show that the highest light emission efficiency and the best reproducibility in the intensity and wavelength are obtained from trapezoidal QWs. The temperature dependence of PL spectra indicates the more localized nature of excitons in the trapezoidal QWs. A plan-view transmission electron microscopy shows that quantum dots (QDs) are formed inside the dislocation loop in trapezoidal QWs. The distribution of QDs in size and composition becomes more uniform with trapezoidal QWs than with rectangular QWs, leading to superior light-emission characteristics. It is suggested that QD engineering and dislocation control are possible, to some extent, by the modulation of the QW shape in InGaN/GaN-based light-emitting devices.

Detectors on the “Universitetsky‐Tatiana” satellite measured a smoothly varying intensity of UV radiation from the night‐time atmosphere in the nadir direction and the intensity of the energetic electron flux at the orbit. At high latitudes the UV intensity in the auroral oval is interpreted as being due to electrons penetrating into the atmosphere. At middle latitudes the UV intensity is an order of magnitude less and more data are needed to reveal the origin of this radiation. Millisecond flashes of UV radiation were observed. The flashes’ energy, temporal profile and global distribution are similar to these parameters for Transient Luminous Events (TLEs). These studies will be continued aboard the next satellite “Tatiana‐2”.

The propagation of Lamb waves in elastic plates is analyzed both numerically and experimentally. A Scanning Laser Doppler Vibrometer (SLDV) is here used to detect and visualize transient waveforms propagating in an elastic plate at low ultrasonic frequencies. The waves are excited by a piezoelectric crystal glued to the plate surface and actuated by sinusoidal pulses of varying frequency. The pulse sequence is triggered by the SLDV internal controller so that phase and delay information are preserved. Such information allows visualization of the waveform pattern as it propagates over the plate surface. The experiment produces animated displacement maps where the interaction with discontinuities in the plate such as defects becomes apparent. This capability suggests application of the SLDV technique as part of an overall damage detection methodology which combines the recognized sensitivity of ultrasonic waves with the localization of damage via wavefield visualization. The interpretation of the experimental results is aided by numerical simulations of ultrasonic waves in plate structures. The simulations are performed using a Local Interaction Simulation Approach (LISA), which represents a simple and effective tool for simulating and visualizing waveforms in isotropic or orthotropic plate‐like structures.

We compared the haemodynamic effects of nicardipine and sodium nitroprusside after coronary artery bypass graft surgery. When post-surgery systolic blood pressure reached > 150 mmHg, patients were randomly given nicardipine (N group, n = 26) or sodium nitroprusside (S group, n = 21). The drugs were infused at a rate of 2 μg/kg per min for 10 min. If the target blood pressure (120-140 mmHg) was not achieved, the infusion rate was increased by 1 üg/kg per min every 10 min. Cardiac and stroke volume indices had increased significantly in the N group after 10 min and in both groups after 60 min. The infusion duration and total dose of drug were significantly lower in the N group compared with the S group. Nicardipine infusion controlled post-operative hypertension more rapidly and was superior to sodium nitroprusside in maintaining left ventricular performance immediately after drug infusion.

The 49630 bp spo0H-rrnH region of the Bacillus subtilis genome has been fully sequenced. The sequence contains one partial and 62 complete ORFs, one partial and three complete rRNA genes and a cluster of six tRNA genes. The direction of the transcription and translation of 61 ORFs is the same as that of the movement of the replication fork. A homology search of 40 ORFs in newly determined sequence revealed that 27 of them had significant similarity to known proteins such as elongation factor G, elongation factor Tu, pseudouridine synthase I and ribsosomal proteins. Two adjacent genes, ybaD and ybaE, appeared to encode proteins belonging to the ATP-binding cassette (ABC) family.

CFC-101 is a novel Pseudomonas vaccine with high effectiveness against Pseudomonas infection and is currently under clinical evaluation. The general pharmacological properties of this vaccine were evaluated in mice, rats, guinea pig ileum, and dogs. In vivo doses of 0.2, 2.0 and 20 mg/kg given by intramuscular route, or in vitro concentrations up to 50 micrograms/ml were used. Intramuscular administration of CFC-101 vaccine had no effect on the central nervous system except that the body temperature of rats was slightly decreased at the highest dose, 20 mg/kg. CFC-101 vaccine did not affect the function of smooth muscles, gastrointestinal system, and cardiovascular and respiratory systems. In water and electrolytes excretion test, a decrease in urine output and an elevation of the excretion of Na+, Cl- and total protein at the highest dose (20 mg/kg) were observed. In summary, CFC-101 vaccine had no pharmacological effect in these studies even up to the 100-fold clinical dose, 2 mg/kg.

Mg-doped p-type GaN epilayers grown by metalorganic chemical vapor deposition exhibit two different types of photoluminescence (PL) characteristics depending on Mg doping rate; the existence of critical Mg concentration is found where both electrical and optical characteristics show an abrupt change in their behavior. In samples with relatively low Mg concentration, a band edge emission, a peak associated with shallow donor-acceptor pair recombination, and a 2.8 eV blue band emission appear in the PL spectrum. Intensities of all three PL peaks decrease with increasing annealing temperature; the blue band quenches most rapidly. In contrast, in samples grown with high ratio of Mg/Ga flow rate, only a strong blue emission band is observed and the intensity of the blue band increases with the annealing temperature suggesting a different origin from the blue band of lightly doped samples. From the annealing temperature dependence of the blue band intensity, we speculate that the emission mechanism of the blue ...