The biotransformation of 14-deoxy-14-methylenetriptolide by Neurospora crassa CGMCC AS 3.1604 to produce a new hydroxylation derivative was studied. The structure of this novel compound was determined using spectral data. This biotransformation using whole cells conditioned for 4 days transformed approximately 65% (mol ratio) of the substrate into the compound (5R)-5-hydroxy-14-deoxy-14-methyle...

LANGUAGE NOTE | Document text in Chinese; abstract also English.
 Developments research have made culturing human embryos beyond the 14-day limit seem technologically feasible. In article “Emerging Human Embryo Research Technologies, Rule, and Special Status of Embryo,” authors examine a proposal for new embryo embryoid guidelines by reviewing history emerging areas that are impacted these...

Current models of the peopling of the higher-elevation zones of the Tibetan Plateau postulate that permanent occupation could only have been facilitated by an agricultural lifeway at ~3.6 thousand calibrated carbon-14 years before present. Here we report a reanalysis of the chronology of the Chusang site, located on the central Tibetan Plateau at an elevation of ~4270 meters above sea level. Th...

In 1988, Carbon-14 findings from three Accelerator Mass Spectrometer (AMS) Labs independently dated a sample removed from the Shroud of Turin: unarguably the most widely studied linen cloth in history. The dates reported ranged between 126

Using the California Institute of Technology/Jet Propulsion Laboratory two-dimensional transport model, with transport coefficients taken from Yang and Tung (1989), we study the time evolution of excess carbon 14 in the stratosphere and the troposphere from October, 1963 to December, 1966. The model provides a satisfactory simulation of the observed data. Due to the impulsive nature of its so...

Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology c...

Four children in the same family have 47, +der (14), t(9;14) (p24;q21). Their mothers are sisters with 46,XX,t(9;14) (p24;q21). Clinical features of the children are similar to those of others reported to have partial 14 trisomy.

That is, carbon-14 decays into nitrogen-14, an electron, and an electron antineutrino. Laboratory experiments demonstrate that it is not possible to predict when any given nucleus will decay. In addition, the probability of decay in the next time interval dt is completely independent of how long the nucleus has lasted up to that point, be it an attosecond or a billion years. What this means is ...

6-O-Methylerythromycin B has been synthesized from erythromycin B via regioselective methylation of the 6-hydroxyl group in 71% overall yield. This compound shows in vitro antibacterial activity comparable to erythromycins A and B and exhibits superior in vivo activity with improved pharmacokinetic properties.