Synthesis and EL Properties of Conjugated Copolymer Materials Containing Various Comonomers

1 Results Polymeric light-emitting diodes (PLEDs) have attracted much scientific and technological research interest due to a number of advantages over inorganic or organic small molecules for use in LEDs: better processability,lower operating voltages,faster response times,lower production costs,and high flexibility.Polyfluorene has been selected for the polymer backbone,because of its large band gap,facile substitution at the C9 position of fluorene,good chemical and thermal stability,and high photolu...     

Shock induces a long-lasting elevation of blood glucose in Aplysia.

Glucose, and not trehalose, was found to be the main blood sugar in Aplysia californica. Changes in blood glucose in response to stress produced by electric shock were measured in blood obtained both from animals dissected within ten minutes of shocking and from catheterized animals at various intervals, up to two and a half hours after the shock. Electric shock increased blood glucose levels. The rise in blood sugar continued as long as two and a half hours after shock.     

Epstein-Barr virus infection and replication in a human epithelial cell system.

Epstein-Barr virus, a human herpesvirus with oncogenic potential, infects two target tissues in vivo: B lymphocytes, where the infection is largely non-productive, and stratified squamous epithelium in which virus replication occurs. The interaction with B cells, initiated through virus binding to the B-cell surface molecule CR2 (ref. 4), has been studied in vitro and the virus 'latent' genes associated with B-cell growth transformation defined. By comparison, viral infection of epithelium remains poorly understood, reflecting the lack of an appropriate cell-culture model. Here we describe the development of such a model using as targets CR2-expressing transfected cells of two independent human epithelial lines. A high proportion of these cells bind virus and become actively infected, expressing the small EBER RNAs (small non-polyadenylated virus-coded RNAs) and the Epstein-Barr nuclear antigen 1 but not other latent proteins; thereafter, under conditions favouring epithelial differentiation, up to 30% of the cells can be induced to enter virus productive cycle with some progressing to full virus replication. We find significant differences between laboratory virus strains in their ability to infect epithelium that do not correlate with their B-cell growth-transforming activity.     

Depletion of hypothalamic norepinephrine reduces the fever induced by polyriboinosinic acid: polyribocytidylic acid (Poly I:Poly C) in rats

Administration of either Poly I:Poly C (0.05-0.50 micrograms) or norepinephrine (2-8 micrograms) into the anterior hypothalamic area produced a dose-related fever in rats. The fever induced by Poly I:Poly C was attenuated after selective depletion of norepinephrine in the hypothalamus. However, selective depletion of hypothalamic norepinephrine did not affect the fever induced by intrahypothalamic norepinephrine. The data indicate that Poly I:Poly C may act to induce fever through the endogenous release of norepinephrine from the rat's hypothalamus.     

Evidence for several waves of global transmission in the seventh cholera pandemic

Vibrio cholerae is a globally important pathogen that is endemic in many areas of the world and causes 3-5 million reported cases of cholera every year. Historically, there have been seven acknowledged cholera pandemics; recent outbreaks in Zimbabwe and Haiti are included in the seventh and ongoing pandemic. Only isolates in serogroup O1 (consisting of two biotypes known as 'classical' and 'El Tor') and the derivative O139 can cause epidemic cholera. It is believed that the first six cholera pandemics were caused by the classical biotype, but El Tor has subsequently spread globally and replaced the classical biotype in the current pandemic. Detailed molecular epidemiological mapping of cholera has been compromised by a reliance on sub-genomic regions such as mobile elements to infer relationships, making El Tor isolates associated with the seventh pandemic seem superficially diverse. To understand the underlying phylogeny of the lineage responsible for the current pandemic, we identified high-resolution markers (single nucleotide polymorphisms; SNPs) in 154 whole-genome sequences of globally and temporally representative V. cholerae isolates. Using this phylogeny, we show here that the seventh pandemic has spread from the Bay of Bengal in at least three independent but overlapping waves with a common ancestor in the 1950s, and identify several transcontinental transmission events. Additionally, we show how the acquisition of the SXT family of antibiotic resistance elements has shaped pandemic spread, and show that this family was first acquired at least ten years before its discovery in V. cholerae.     

Can We Predict Exchange Rate Movements at Short Horizons?

This paper explains the unpredictability of exchange rate movements at short horizons and provides a plausible answer on the exchange rate disconnect puzzle. By generalizing Chaboud and Wright's (Journal of International Economics 2005; 66 : 349–362) work, it is shown that exchange rates follow a martingale process at short horizons but over long horizons may contain some predictable structure. The empirical results applied to several major currencies of the US dollar support our hypothesis. This evidence is not coincided with the explanation of the inefficient market hypothesis under which exchange rate movements can be predictable in both short and long horizons. Copyright © 2011 John Wiley & Sons, Ltd.     

The scotopic visual sensitivity of four species of trout: a comparative study

We compared the maximum scotopic visual sensitivity of 4 species of trout from twilight (mesotopic) to fully dark-adapted vision. Scotopic vision is the minimum number of photons to which a fully dark-adapted animal will show a behavioral response. A comparison of visual sensitivity under controlled laboratory conditions showed that brown trout ( Salmo trutta ) and brook trout ( Salvelinus fontinalis ) had maximum scotopic thresholds (1.1 × 10 –4 μmol ? m –2 s –1 , ～0.005 lux) 2 times lower than rainbow trout ( Oncorhyncus mykiss ) and Snake River cutthroat trout ( Oncorhynchus clarki bouvieri ), which did not differ from each other (2.1 × 10 –4 μmol ? m –2 s –1 , ～0.01 lux). A literature review tended to corroborate these results in that brown trout and brook trout were reported to be more active during the night and at twilight than cutthroat trout and rainbow trout. We also measured light intensity within open versus shaded reaches during the day, dusk, and night in 3 Rocky Mountain streams. The scotopic sensitivity of brown trout and brook trout was sufficient to allow foraging during all twilight periods and under average nighttime light intensities in open and shaded reaches, whereas the scotopic sensitivity of rainbow trout and cutthroat trout may restrict their foraging to relatively bright nocturnal conditions (twilight or a moonlit night). Native cutthroat trout restoration efforts may have greater success in open versus shaded stream reaches in the Rocky Mountains and elsewhere.