Drexel University is a private research university with three campuses in Philadelphia and one in Sacramento, California. It was founded in 1891 by Anthony J. Drexel, a noted financier and philanthropist. Drexel offers over 70 full-time undergraduate programs and accelerated degrees. At the graduate level, the university offers over 100 masters, doctoral, and professional programs, many available part-time.Drexel is best known for the cooperative education program . Drexel's co-op is regularly ranked as one of the best co-op programs in the United States. Participating students have a variety of opportunities to gain up to 18-months of paid full-time working experience before graduation. The university has a large network of more than 1,600 corporate, governmental, and non-profit partners in 28 states and 25 international locations. The employers include top ranked multinational law firms, banks, corporations, and many Fortune 500 companies, such as Goldman Sachs, Microsoft, and Procter & Gamble.Shanghai Jiao Tong University’s academic ranking of world universities ranks Drexel 401-500 and Times Higher Education World University Rankings placed Drexel among the top 200 universities in the World. In U.S. News & World Report's annual "America's Best Colleges List", the university has been ranked consistently among the "Best National Universities – Top Schools." The 2012 rankings place Drexel third in their list of “Up and Coming National Universities” for "promising and innovative changes in the areas of academics, faculty, and student life." In addition, the National Science Foundation and the 2009 Lombardi Report also ranked Drexel among the top 50 private comprehensive research universities. Drexel University ranks #45 among "Research Universities by Salary Potential" in the United States. Wikipedia.
Lowe M.R.,Drexel University
Obesity Reviews | Year: 2015
The relationship between dieting and body mass has a long and controversial history. This paper aims to help resolve this issue by making two key distinctions. The first is between dieting as a cause of weight gain/regain and as a proxy risk factor for identifying non-obese individuals prone to weight gain for reasons other than dieting. The second is between the body mass that is attained following one or more weight loss/regain cycles and the body mass that might have been reached had dieting never been undertaken. Evidence is reviewed on the relation between recent diet-induced weight loss and sustained weight loss (weight suppression), on the one hand, and weight regain, on the other hand. Furthermore, the reason that a history of dieting in non-obese individuals reflects a susceptibility to future weight gain is explained. It is concluded that (i) diet-induced weight loss hastens weight regain but a history of weight loss diets does not cause weight gain beyond that which would occur in the absence of dieting, and (ii) weight loss dieting in non-obese individuals does not cause future weight gain but is simply a proxy risk factor reflecting a personal vulnerability to weight gain and living in an obesogenic environment. Obesity Reviews © 2015 International Association for the Study of Obesity.
Gill F.B.,Drexel University
Auk | Year: 2014
The polytypic species concept unites populations that theoretically could and would interbreed were the opportunity to arise. This concept places the burden of proof of reproductive incapability and species status on those claiming species or higher rank. Advances in our understanding of the nature of reproductive isolation, the genetics of speciation, the limited role of gene flow, the power of directional selection, and the dynamics of hybridization support a different null hypothesis for taxonomic decisions, one that places the burden of proof on 'lumping' rather than on 'splitting' taxa at the species level. Switching the burden of proof provides an improved conceptual basis for the recognition of many allopatric island taxa and subspecies groups that merit species status. Taxonomic revisions based on these advances predictably confirm that distinct sister populations once lumped as polytypic species are independent evolutionary lineages that exhibit essential reproductive isolation. Release from the concerns about hybridization also positions proposed species for timely taxonomic decisions. The stage is set to proactively redefine polytypic species to separate component species for the 21st century. The improved species classification will better reflect phylogeny and evolutionary status, characterize biodiversity more accurately, guide improved sampling patterns of bird populations for systematic studies, and enable informed conservation decisions. © 2014 American Ornithologists' Union.
Naguib M.,Oak Ridge National Laboratory |
Gogotsi Y.,Drexel University
Accounts of Chemical Research | Year: 2015
CONSPECTUS: Two-dimensional (2D) materials have attracted much attention in the past decade. They offer high specific surface area, as well as electronic structure and properties that differ from their bulk counterparts due to the low dimensionality. Graphene is the best known and the most studied 2D material, but metal oxides and hydroxides (including clays), dichalcogenides, boron nitride (BN), and other materials that are one or several atoms thick are receiving increasing attention. They may deliver a combination of properties that cannot be provided by other materials. The most common synthesis approach in general is by reacting different elements or compounds to form a new compound. However, this approach does not necessarily work well for low-dimensional structures, since it favors formation of energetically preferred 3D (bulk) solids. Many 2D materials are produced by exfoliation of van der Waals solids, such as graphite or MoS2, breaking large particles into 2D layers. However, these approaches are not universal; for example, 2D transition metal carbides cannot be produced by any of them. An alternative but less studied way of material synthesis is the selective extraction process, which is based on the difference in reactivity and stability between the different components (elements or structural units) of the original material. It can be achieved using thermal, chemical, or electrochemical processes. Many 2D materials have been synthesized using selective extraction, such as graphene from SiC, transition metal oxides (TMO) from layered 3D salts, and transition metal carbides or carbonitrides (MXenes) from MAX phases. Selective extraction synthesis is critically important when the bonds between the building blocks of the material are too strong (e.g., in carbides) to be broken mechanically in order to form nanostructures. Unlike extractive metallurgy, where the extracted metal is the goal of the process, selective extraction of one or more elements from the precursor materials releases 2D structures. In this Account, in addition to graphene and TMO, we focused on MXenes as an example for the use of selective extraction synthesis to produce novel 2D materials. About 10 new carbides and carbonitrides of transition metals have been produced by this method in the past 3 years. They off er an unusual combination of metallic conductivity and hydrophilicity and show very attractive electrochemical properties. We hope that this Account will encourage researchers to extend the use of selective extraction to other layered material systems that in turn will result in expanding the world of nanomaterials in general and 2D materials in particular, generating new materials that cannot be produced by other means. (Figure Presented). © 2014 American Chemical Society.
Jacobs J.,Drexel University
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2014
The theta oscillation is a neuroscience enigma. When a rat runs through an environment, large-amplitude theta oscillations (4-10 Hz) reliably appear in the hippocampus's electrical activity. The consistency of this pattern led to theta playing a central role in theories on the neural basis of mammalian spatial navigation and memory. However, in fact, hippocampal oscillations at 4-10 Hz are rare in humans and in some other species. This presents a challenge for theories proposing theta as an essential component of the mammalian brain, includingmodels of place and grid cells.Here, I examine this issue by reviewing recent research on human hippocampal oscillations using direct brain recordings from neurosurgical patients. This work indicates that the human hippocampus does indeed exhibit rhythms that are functionally similar to theta oscillations found in rodents, but that these signals have a slower frequency of approximately 1-4 Hz. I argue that oscillatorymodels of navigation andmemory derived from rodent data are relevant for humans, but that they should be modified to account for the slower frequency of the human theta rhythm. © 2013 The Author(s) Published by the Royal Society. All rights reserved.
McGonigle P.,Drexel University
Biochemical Pharmacology | Year: 2014
There is intense interest in the development and application of animal models of CNS disorders to explore pathology and molecular mechanisms, identify potential biomarkers, and to assess the therapeutic utility, estimate safety margins and establish pharmacodynamic and pharmacokinetic parameters of new chemical entities (NCEs). This is a daunting undertaking, due to the complex and heterogeneous nature of these disorders, the subjective and sometimes contradictory nature of the clinical endpoints and the paucity of information regarding underlying molecular mechanisms. Historically, these models have been invaluable in the discovery of therapeutics for a range of disorders including anxiety, depression, schizophrenia, and Parkinson's disease. Recently, however, they have been increasingly criticized in the wake of numerous clinical trial failures of NCEs with promising preclinical profiles. These failures have resulted from a number of factors including inherent limitations of the models, over-interpretation of preclinical results and the complex nature of clinical trials for CNS disorders. This review discusses the rationale, strengths, weaknesses and predictive validity of the most commonly used models for psychiatric, neurodegenerative and neurological disorders as well as critical factors that affect the variability and reproducibility of these models. It also addresses how progress in molecular genetics and the development of transgenic animals has fundamentally changed the approach to neurodegenerative disorder research. To date, transgenic animal models\have not been the panacea for drug discovery that many had hoped for. However continual refinement of these models is leading to steady progress with the promise of eventual therapeutic breakthroughs. © 2013 Elsevier Inc.