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Tung R.T.,Brooklyn College | Tung R.T.,The Graduate Center, CUNY
Applied Physics Reviews | Year: 2014

The formation of the Schottky barrier height (SBH) is a complex problem because of the dependence of the SBH on the atomic structure of the metal-semiconductor (MS) interface. Existing models of the SBH are too simple to realistically treat the chemistry exhibited at MS interfaces. This article points out, through examination of available experimental and theoretical results, that a comprehensive, quantum-mechanics-based picture of SBH formation can already be constructed, although no simple equations can emerge, which are applicable for all MS interfaces. Important concepts and principles in physics and chemistry that govern the formation of the SBH are described in detail, from which the experimental and theoretical results for individual MS interfaces can be understood. Strategies used and results obtained from recent investigations to systematically modify the SBH are also examined from the perspective of the physical and chemical principles of the MS interface. © 2014 AIP Publishing LLC. Source

Grov C.,The Graduate Center, CUNY | Grov C.,Center for Educational Studies and Training CHEST
AIDS and Behavior | Year: 2012

There has been little evaluation regarding whether men who have sex with men (MSM) recruited in one type of venue differ in behavioral and demographic characteristics from those recruited in others. We surveyed MSM in gay bars/clubs (n = 199), bathhouses (n = 194), and off Craigslist.org (n = 208). Men in bathhouses reported the greatest average number of partners and were less likely to disclose their HIV status. Among men reporting anal sex; those on Craigslist reported the least condom use. Finally, men surveyed in gay bars/clubs were the youngest of the three and the most likely to be single; they also reported the highest levels of attachment to the gay community and the most frequent alcohol use. Our findings demonstrate the need to tailor HIV prevention efforts to the location in which they are targeted, and for researchers to evaluate if participants differ by recruitment source. a revelar su status de VIH. Entre los hombres que reportaron sexo anal, aquellos encuestados en Craigslist.org reportaron el menor uso de condones. Finalmente, los hombres encuestados en bares y clubes gay resultaron ser más jóvenes y con mayor tendencia a ser solteros. También reportaron mayor conexión con la comunidad gay y mayor uso de alcohol. Nuestros resultados demuestran la necesidad de adaptar esfuerzos de prevención de VIH a lugares específicos, y que los investigadores analicen si los participantes difieren, dependiendo de dónde fueron reclutados. © 2011 Springer Science+Business Media, LLC. Source

Goldstein J.,The Graduate Center, CUNY
Antipode | Year: 2013

This essay provides an analysis of the "dirty" history and geography of enclosure, as both an instance of primitive accumulation and a production of nature. Specifically, I reconsider the English enclosures as a struggle over the land-use designation of "waste". Whereas both open fields and common waste lands were an essential and valuable part of the common right economy, advocates of enclosure came to see these same lands as wasted commons; lands that were potentially, but not yet, improved. This dialectic of waste and potential permeates the fabric of the nature produced through enclosure, which I name terra economica. Typically, this terrain has been understood as a passive repository of free resources, extending across absolute space. While such accounts consider the making of nature into a universal means of production, it is equally important to consider the ways in which nature is produced as a universal condition of production. © 2012 The Author. Antipode. © 2012 Antipode Foundation Ltd. Source

Ranaldi R.,The Graduate Center, CUNY
Reviews in the Neurosciences | Year: 2014

Reward seeking is controlled by conditioned stimuli (CSs). There is a positive relation between mesocorticolimbic dopamine (DA) and the performance of learned reward-directed behavior. The mechanisms by which reward-, including drug-, associated stimuli come to acquire the capacity to activate the DA systems are not fully understood. In this review, we discuss the possible neurochemical mechanisms within the ventral tegmental area that may be involved in how CSs acquire the capacity to activate ventral tegmental area (VTA) DA neurons based on principles of long-term potentiation in the VTA and the role of mesocorticolimbic DA in reward-related learning. We propose that CSs function as such because they acquire the capacity to activate VTA DA neurons. Furthermore, CSs come to acquire this control of VTA DA cells when there is coincident N-methyl-d-aspartate receptor stimulation on VTA DA cells and strong depolarization of VTA DA cells, possibly by muscarinic acetylcholine receptor stimulation on these cells. This coincident activity leads to the strengthening of CS-associated glutamatergic synapses and the control by CSs of mesocorticolimbic DA systems and reward-directed behavior. © 2014 by De Gruyter. Source

Chatterjee S.,The Graduate Center, CUNY
Nanoscale | Year: 2012

Self-assembly based on nucleic acid systems has become highly attractive for bottom-up fabrication of programmable matter due to the highly selective molecular recognition property of biomolecules. In this context, Y-shaped DNA (Y-DNA) provides an effective building block for forming unique self-assembled large-scale architectures. The dimension and growth of the nano- and microstructures depend significantly on the configurational stability of Y-DNA as a building block. Here we present structural studies of Y-DNA systems using a time-resolved FRET (Förster resonance energy transfer) technique. A fluorophore (Alexa 488) and an acceptor (DABCYL) were placed at two different ends of Y-DNA, and the lifetime of the fluorophore was measured to probe the relative distance between the donor and acceptor. Our results confirmed different distances between the arms of the Y-DNA and highlighted the overall structural integrity of the Y-DNA system as a leading building block for molecular self-assembly. Temperature dependent lifetime measurements indicated configurational changes in the overall Y-DNA nanoarchitecture above 40 °C. Source

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