A motif for heteronuclear C[triple bond, length as m-dash]E (E = Si, Ge, Sn, Pb) bonding: Lewis acid-base pair strategy.

The design and characterization of the heteronuclear group 14 C[triple bond, length as m-dash]E (E = Si, Ge, Sn, Pb) triple bonds have attracted intensive interest in the past few decades. In the current work, utilizing the advantages of N-heterocyclic carbenes (NHCs) and Lewis acid-base pair strategy, we theoretically designed a new class of compounds III-1, i.e.

A sixteen-valence-electron carbon-group 13 family with global penta-atomic planar tetracoordinate carbon: an ionic strategy.

The design of planar tetracoordinate carbon (ptC) has always been a challenge due to its unique bonding mode that necessitates the perfect balance between the carbon center and surrounding ligands both electronically and mechanically. A unique type of 18-valence-electron (18ve) template, i.e.

Mono-silicon isoelectronic replacement in CAl : van't hoff/le bel carbon or not?

In cluster studies, the isoelectronic replacement strategy has been successfully used to introduce new elements into a known structure while maintaining the desired topology. The well-known penta-atomic 18 valence electron (ve) species and its Al /Si or Al/Si isoelectronically replaced clusters CAl Si , CAl Si , , and , all possess the same anti-van't Hoff/Le Bel skeletons, that is, nontraditional planar tetracoordinate carbon (ptC) structure. In this article, however, we found that such isoelectronic replacement between Si and Al does not work for the 16ve-CAl with the traditional van't Hoff/Le Bel tetrahedral carbon (thC) and its isoelectronic derivatives CAl X (X = Ga/In/Tl).

Responses of soil active carbon and nitrogen to short-term warming in alpine treeline of west Sichuan, China.

Alpine treeline ecosystem is more sensitive to global warming under low temperature limitation with the aggravation of greenhouse effect, which may directly affect plant growth and soil carbon and nitrogen processes. We expected that climate warming would change soil active carbon and nitrogen content in alpine ecosystems. This experiment was conducted in long-term research station of alpine forest ecosystems, in Lixian County, Sichuan Province.

A kinetically persistent isomer found for pentazole: a global potential energy surface survey.

Among the N5R family, pentazoles (A1) with a 103-year-old research history remain the only class of kinetically persistent isomers. Aided by the first global isomeric survey and substitution study of N5H at the composite CBS-QB3 level, we predicted a new N5R isomer (C1) with kinetic stability close to pentazoles.

CAlX (X = B/Al/Ga/In/Tl) with 16 valence electrons: can planar tetracoordinate carbon be stable?

As a perpetual chemical curiosity, planar tetracoordinate carbon (ptC) that violates the traditional tetrahedral carbon (thC) has made enormous achievements. In particular, the 18-valence-electron (18ve) counting rule has been found to be very effective in predicting ptC structures, as in CX (X = Al/Ga/In/Tl). By contrast, the corresponding neutral CX with 16ve each takes the thC form like methane.

[Application of regression tree in analyzing the effects of climate factors on NDVI in loess hilly area of Shaanxi Province].

Based on the 10-day SPOT VEGETATION NDVI data and the daily meteorological data from 1998 to 2007 in Yan' an City, the main meteorological variables affecting the annual and interannual variations of NDVI were determined by using regression tree. It was found that the effects of test meteorological variables on the variability of NDVI differed with seasons and time lags. Temperature and precipitation were the most important meteorological variables affecting the annual variation of NDVI, and the average highest temperature was the most important meteorological variable affecting the inter-annual variation of NDVI.

[Nitrate pollution in groundwater for drinking and its affecting factors in Hailun, northeast China].

Nitrate pollution in groundwater has become a worldwide problem. It may affect the water quality for daily use and thus the health of people. The temporal and spatial characteristics of nitrate pollution in the groundwater were addressed by sample analysis of the drinkable water from 157 wells in Hailun, Heilongjiang, northeastern China.

Flux enhancement during ultrafiltration of produced water using turbulence promoter.

Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux.

Voltage-dependent slowly activating anion current regulated by temperature and extracellular pH in mouse B cells.

Voltage-dependent, outwardly rectifying anion channels have been described in various cells including lymphocytes. In this study, we found that murine B cells express the voltage-dependent slowly activating anion channels (VSACs). Using a whole-cell configuration, I (VSAC) in Bal-17 was induced by a sustained depolarization (>0 mV) which was remarkably facilitated at 35 degrees C (Q (10)=23 at 30 mV of clamp voltage).

Role of arachidonic acid in hyposmotic membrane stretch-induced increase in calcium-activated potassium currents in gastric myocytes.

Aim: To study effects of arachidonic acid (AA) and its metabolites on the hyposmotic membrane stretch-induced increase in calcium-activated potassium currents (I(KCa)) in gastric myocytes.

Methods: Membrane currents were recorded by using a conventional whole cell patch-clamp technique in gastric myocytes isolated with collagenase.

Results: Hyposmotic membrane stretch and AA increased both I(K(Ca))) and spontaneous transient outward currents significantly.

Effects of unsaturated fatty acids on calcium-activated potassium current in gastric myocytes of guinea pigs.

Aim: To investigate the effects of exogenous unsaturated fatty acids on calcium-activated potassium current (I(K(Ca))) in gastric antral circular myocytes of guinea pigs.

Methods: Gastric myocytes were isolated by collagenase from the antral circular layer of guinea pig stomach. The whole-cell patch clamp technique was used to record I(K(Ca)) in the isolated single smooth muscle cells with or without different concentrations of arachidonic acid (AA), linoleic acid (LA), and oleic acid (OA).

Effect of actin microfilament on potassium current in guinea pig gastric myocytes.

Aim: To investigate the effect of actin microfilament on potassium current and hyposmotic membrane stretch-induced increase of potassium current in gastric antral circular myocytes of guinea pig.

Methods: Whole-cell patch clamp technique was used to record potassium current in isolated gastric myocyes.

Results: When the membrane potential was clamped at -60 mV, an actin microfilament disruptor, cytochanlasin-B(Cyt-B, 20 micromol/L in pipette) increased calcium-activated potassium current (I(K(Ca))) and delayed rectifier potassium current (I(K(V))) to 138.

Role of calcium-activated potassium currents in CNP-induced relaxation of gastric antral circular smooth muscle in guinea pigs.

Aim: To investigate ion channel mechanism in CNP-induced relaxation of gastric circular smooth muscle in guinea pigs.

Methods: Spontaneous contraction of gastric smooth muscle was recorded by a four -channel physiograph. The whole cell patch-clamp technique was used to record calcium-activated potassium currents and membrane potential in the gastric myocytes isolated by collagenase.