Comparative study of three short-chain neurotoxins from the venom of Naja kaouthia (Yunnan, China)

Three short-chain neurotoxins named NT-I, NT-II, and NT-III were purified from the venom of Naja kaouthia, a snake distributed throughout the south of Yunnan province, China, by a series of chromatographic steps, including an FPLC Resource S column. Their molecular weights, determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS, were 6952.19 Da, 6854.92 Da, and 6828.80 Da, respectively. NT-I consisted of 62 amino acid residues, and the other two consisted of 61 amino acid residues, including 8 cysteines. After hydrolysis by endoproteinase Glu-C, their primary sequences were determined. A test of their activities demonstrated that they effectively inhibited muscle contractions induced by electric stimulation. Furthermore, the extent of inhibition caused by NT-II and NT-III was less than that of NT-I. The IC(50)s were 0.04 mug/ml, 0.20 mug/ml, and 0.23 mug/ml for NT-I, NT-II, and NT-III, respectively. Compared with NT-II and NT-III, the higher activity of NT-I may be a result of the amino acid residue substitution Ile36 to Arg36.

Lack of mtDNA control region variation in Hainan Eld's deer: Consequence of a recent population bottleneck?

We find no genetic variation at 550bp of mtDNA control region among 55 Hainan Eld's deer in an island population that has suffered recent population contractions. Congeneric species show high levels of variation at this locus. We use a simulation approach to test the likelihood of various bottleneck scenarios, and show, in the context of what is known about the recent demographic history of this population, that there are credible scenarios for a bottleneck driven by hunting pressure in the 1960s that could account for the lack of variation at this locus.

Neuro-Stimulus Chip with Photodiodes Array for Sub-retinal Implants

A prototype neuro-stimulus chip for sub-retinal implants in blind patients affected by Age-related Macular Degeneration (AMD) or Retinitis Pigmentosa (RP) is presented in this paper. This retinal prosthetic chip was designed to replace the degenerated photoreceptor cells, and in order to stimulate directly the remaining healthy layers of retinal neurons. The current stimulus circuits are monolithic integrated with photodiodes (PD) array, which can convert the illumination on the eyes into bi-phasic electrical pulses. In addition, a novel charge cancellation circuit is used to discharge the electrodes for medical safty. The prototype chip is designed and fabricated in HJTC 0.18 mu m N-well CMOS 1P6M Mix-signal process, with a +/- 2.5 V dual voltage power supply.

Failure of the plasma-sprayed coating of lanthanum hexaluminate

Lanthanum magnesium hexaluminate (LaMgAl11O19, LMA) is an attractive material for thermal barrier coatings (TBCs), and the failure of its coating was studied in this work by thermal cycling, X-ray diffraction, dilatometric measurement and thermal gravimetric-differential thermal analysis. The dilatometric measurement indicates that even though the bulk material of LMA has a higher sintering-resistance than the typical TBC material, i.e. yttria-stabilized zirconia (YSZ), the plasma sprayed coating of LMA has two serious contractions due to the re-crystallization of LMA and phase transitions of alumina.

AN EFFECTIVE TRIPHASIC CATALYTIC-SYSTEM FOR OXIDATION OF BENZYL ALCOHOL UNDER PHASE-TRANSFER CONDITIONS

A tri-phasic catalytic system consisting of aqueous hydrogen peroxide, benzyl alcohol and a solid catalyst such as tungsten trioxide has been proved effective for the oxidation of benzyl alcohol in the presence of cetyl trimethyl aniline bromide (CTMAB). At first, the oxide reacts with CTMAB to form a complex, which can be oxidized by aqueous hydrogen peroxide to form a peroxide which effectively oxidizes benzyl alcohol.

Inhibition Effect of 2,3,5-Triphenyl-2H-tetrazolium Chloride and 2,4,6-Tri(2-pyridyl)-s-triazine on the Corrosion of Mild Steel in 1 mol/L HCl and Mechanism Study (II)

The inhibitory effect of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and 2,4,6-tri(2-pyridyl)-s-triazine (TPT) molecules on the corrosion of mild steel in 1 mol/L HCl and microcosmic inhibitory mechanism were investigated by X-ray photoelectron spectroscopy and ellipsometry. XPS results showed that C Is and N Is peaks of TTC, C Is and N Is peaks of TPT and their integral areas were obtained, which suggested the layer of the inhibitors (TTC or TPT) should have effectively protected the mild steel surface from the corrosion; and the depression from the inhibitors for the corrosion of mild steel surface was studied using ellipsometry combined with potentiodynamic polarization and the phasic difference was gained, which displayed the inhibitory coverage of the inhibitors formed.