State University of New York System

About: State University of New York System is a education organization based out in Albany, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 54077 authors who have published 78070 publications receiving 2985160 citations.

High contrast in vitro and in vivo photoluminescence bioimaging using near infrared to near infrared up-conversion in Tm3+ and Yb3+ doped fluoride nanophosphors.

Abstract: A new approach for photoluminescence imaging in vitro and in vivo has been shown utilizing near infrared to near infrared (NIR-to-NIR) up-conversion in nanophosphors. This NIR-to-NIR up-conversion process provides deeper light penetration into biological specimen and results in high contrast optical imaging due to absence of an autofluorescence background and decreased light scattering. Aqueous dispersible fluoride (NaYF4) nanocrystals (20−30 nm size) co-doped with the rare earth ions, Tm3+ and Yb3+, were synthesized and characterized by TEM, XRD, and photoluminescence (PL) spectroscopy. In vitro cellular uptake was shown by the PL microscopy visualizing the characteristic emission of Tm3+ at ∼800 nm excited with 975 nm. No apparent cytotoxicity was observed. Subsequent animal imaging studies were performed using Balb-c mice injected intravenously with up-converting nanophosphors, demonstrating the high contrast PL imaging in vivo.

A new look at the saturn system: the voyager 2 images.

Abstract: Voyager 2 photography has complemented that of Voyager I in revealing many additional characteristics of Saturn and its satellites and rings. Saturn's atmosphere contains persistent oval cloud features reminiscent of features on Jupiter. Smaller irregular features track out a pattern of zonal winds that is symmetric about Saturn's equator and appears to extend to great depth. Winds are predominantly eastward and reach 500 meters per second at the equator. Titan has several haze layers with significantly varying optical properties and a northern polar "collar" that is dark at short wavelengths. Several satellites have been photographed at substantially improved resolution. Enceladus' surface ranges from old, densely cratered terrain to relatively young, uncratered plains crossed by grooves and faults. Tethys has a crater 400 kilometers in diameter whose floor has domed to match Tethys' surface curvature and a deep trench that extends at least 270° around Tethys' circumference. Hyperion is cratered and irregular in shape. Iapetus' bright, trailing hemisphere includes several dark-floored craters, and Phoebe has a very low albedo and rotates in the direction opposite to that of its orbital revolution with a period of 9 hours. Within Saturn's rings, the "birth" of a spoke has been observed, and surprising azimuthal and time variability is found in the ringlet structure of the outer B ring. These observations lead to speculations about Saturn's internal structure and about the collisional and thermal history of the rings and satellites.

Molecular physiology of the regulation of hepatic gluconeogenesis and glycolysis.

Abstract: Understanding the regulation of hepatic glucose metabolism had its foundation in the elucidation of several pathways, but recent advances have come from the application of molecular genetics. Five years ago little was known about the primary structure of the key regulatory enzymes. Since then, the primary sequence of liver GK, 6-PF-1-K, Fru-1,6-P2ase, PK, PEPCK, and 6-PF-2-K/Fru-2,6-P2ase have been derived from cDNA sequences and/or determined by direct protein sequencing. This has provided new insights into the molecular mechanisms of catalysis and the regulation of these enzymes by covalent modification. Isolation of the cDNAs for these enzymes also has allowed for the quantitation of specific mRNAs and permitted analysis of hormonal control of specific gene expression. The genes for these enzymes have been isolated and sequenced, and their promoter regions are being identified and characterized. Hormone response elements have been delineated in several of the promoters. The promoter regions for 6-PF-2-K/Fru-2,6-P2ase and Fru-1,6-P2ase have also been identified, and future research will focus on the elucidation of the mechanisms whereby hormones regulate the expression of these genes. A number of generalizations can be made about the regulation of gene expression of glycolytic/gluconeogenic enzymes. First, there is coordinate hormonal regulation of gene expression and these effects are consonant with their physiologic actions. Insulin induces the mRNAs that encode glycolytic enzymes and represses the mRNAs that encode gluconeogenic enzymes; cAMP has opposite effects. Both can increase or decrease transcription. Whereas insulin and cAMP affect all of these mRNAs, glucocorticoids appear to have a more restricted action. Second, transcriptional and posttranscriptional regulatory mechanisms are involved. The synthesis of all of the mRNAs discussed is regulated by hormones. Relatively little is known about how mRNA stability is regulated in general, but it is clear that PEPCK mRNA is stabilized by agents that increase the rate of transcription of the gene. Under appropriate metabolic signals this dual control of mRNA synthesis and stability provides for a long-term increase in PEPCK mRNA and protein. Studies with PK mRNA are less direct, but suggest a similar dual mechanism. It will be interesting to see whether multilevel regulation is restricted to these two mRNAs, both of which are involved in the same substrate cycle, or whether the stability of other mRNAs involved in hepatic glucose metabolism is also affected. Third, glucose appears to be important in the regulation of these hepatic genes.(ABSTRACT TRUNCATED AT 400 WORDS)