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a r t i c l e i n f o Keywords: Permian Triassic extinction Meishan South China euxinia Chlorobiaceae biomarker hydrocarbons stable carbon isotopes strontium The Permian–Triassic Boundary event at 252.2 Ma marks the largest extinction of marine fauna in the Phanerozoic and there is a wide consensus that the extinction coincided with an intense oceanic(More)
Dibromoacetic acid (DBA) is a drinking water disinfection by-product. Its analogs, dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are liver carcinogens in rodents. We evaluated the ability of DBA to cause DNA hypomethylation, glycogen accumulation, and peroxisome proliferation that are activities previously reported for the two other haloacetic(More)
Genetic polymorphisms of p53 codon 72 are thought to have significant effects on the metabolism of environmental carcinogens and thus on lung cancer risk, but the reported results are not always consistent. The aim of this study is to investigate the relationship between p53 codon 72 genetic polymorphisms and tobacco use and lung cancer risk in a Chinese(More)
The ability of celecoxib and alpha-difluoromethylornithine (DFMO) to modulate the DNA hypomethylation and the hypermethylation of the estrogen receptor (ER)-alpha gene in colon tumors was evaluated as potential biomarkers for chemoprevention. Colon tumors were induced in rats by azoxymethane. Celecoxib (500 mg/kg), DFMO (100, 1000 and 3000 mg/kg) or(More)
Smart hydrogels, or stimuli-responsive hydrogels, are three-dimensional networks composed of crosslinked hydrophilic polymer chains that are able to dramatically change their volume and other properties in response to environmental stimuli such as temperature, pH and certain chemicals. Rapid and significant response to environmental stimuli and high(More)
An addressable electrode array was used for the production of acid at sufficient concentration to allow deprotection of the dimethoxytrityl (DMT) protecting group from an overlaying substrate bound to a porous reaction layer. Containment of the generated acid to an active electrode of 100 micron diameter was achieved by the presence of an organic base. This(More)
Procedures and results are described for multiplexed immunochemical assays using semiconductor microchips. The mi-crochips used here are miniaturized arrays of individually addressable microelectrodes controlled by active CMOS circuitry. Electrode densities exceed 1000 per cm 2. The array chips are coated with a porous reaction layer material to provide a(More)
To the Editor: In the past 20 years, Baylisascaris procyonis, the common intestinal roundworm of raccoons , has increasingly been recognized as a source of severe human neurologic disease that particularly affects children (1,2). Although human baylisascariasis appears to be rare, the devastating neurologic disease caused by this infection and the lack of(More)
Multiple emulsions, which are widely applied in a myriad of fields because of their unique ability to encapsulate and protect active ingredients, are typically produced by sequential drop-formations and drop-encapsulations using shear-induced emulsification. Here we report a qualitatively novel method of creating highly controlled multiple emulsions from(More)
Polymeric core–shell microparticles with hollow interiors have great potential for use as microencapsulation systems for controlled load/release, [1–3] active protection, [4] and confined microreaction. [5] Core–shell structures with solid shells provide effective encapsulation; however, transport of the encapsulated molecule through the shell is more(More)