Time filter

Source Type

Washington, DC, United States

The University of the District of Columbia is a public university located in the U.S. capital of Washington, D.C. UDC is one of the few urban land-grant universities in the country and a member-school of the Thurgood Marshall College Fund. It is also the only public university in the District of Columbia. Wikipedia.

Pearce M.,University of Canterbury | Zeadally S.,University of the District of Columbia | Hunt R.,University of Canterbury
ACM Computing Surveys

Although system virtualization is not a new paradigm, the way in which it is used in modern system architectures provides a powerful platform for system building, the advantages of which have only been realized in recent years, as a result of the rapid deployment of commodity hardware and software systems. In principle, virtualization involves the use of an encapsulating software layer (Hypervisor or Virtual Machine Monitor) which surrounds or underlies an operating system and provides the same inputs, outputs, and behavior that would be expected from an actual physical device. This abstraction means that an ideal Virtual Machine Monitor provides an environment to the software equivalent to the host system, but which is decoupled from the hardware state. Because a virtual machine is not dependent on the state of the physical hardware, multiple virtual machines may be installed on a single set of hardware. The decoupling of physical and logical states gives virtualization inherent security benefits. However, the design, implementation, and deployment of virtualization technology have also opened up novel threats and security issues which, while not particular to system virtualization, take on new forms in relation to it. Reverse engineering becomes easier due to introspection capabilities, as encryption keys, security algorithms, low-level protection, intrusion detection, or antidebugging measures can become more easily compromised. Furthermore, associated technologies such as virtual routing and networking can create challenging issues for security, intrusion control, and associated forensic processes. We explain the security considerations and some associated methodologies by which security breaches can occur, and offer recommendations for how virtualized environments can best be protected. Finally, we offer a set of generalized recommendations that can be applied to achieve secure virtualized implementations. © 2013 ACM. Source

Srivastava K.,Human Genome Research Institutes | Srivastava A.,University of the District of Columbia

Background: MicroRNAs (miRNAs) are small RNA molecules that regulate the expression of corresponding messenger RNAs (mRNAs). Variations in the level of expression of distinct miRNAs have been observed in the genesis, progression and prognosis of multiple human malignancies. The present study was aimed to investigate the association between four highly studied miRNA polymorphisms (mir-146a rs2910164, mir-196a2 rs11614913, mir-149 rs2292832 and mir-499 rs3746444) and cancer risk by using a two-sided meta-analytic approach. Methods: An updated meta-analysis based on 53 independent case-control studies consisting of 27573 cancer cases and 34791 controls was performed. Odds ratio (OR) and 95% confidence interval (95% CI) were used to investigate the strength of the association. Results: Overall, the pooled analysis showed that mir-196a2 rs11614913 was associated with a decreased cancer risk (OR = 0.846, P = 0.004, TT vs. CC) while other miRNA SNPs showed no association with overall cancer risk. Subgroup analyses based on type of cancer and ethnicity were also performed, and results indicated that there was a strong association between miR-146a rs2910164 and overall cancer risk in Caucasian population under recessive model (OR = 1.274, 95%CI = 1.096-1.481, P = 0.002). Stratified analysis by cancer type also associated mir-196a2 rs11614913 with lung and colorectal cancer at allelic and genotypic level. Conclusions: The present meta-analysis suggests an important role of mir-196a2 rs11614913 polymorphism with overall cancer risk especially in Asian population. Further studies with large sample size are needed to evaluate and confirm this association. Source

Development of acquired antihormone resistance exposes a vulnerability in breast cancer: estrogen-induced apoptosis. Triphenylethylenes (TPEs), which are structurally similar to 4-hydroxytamoxifen (4OHT), were used for mechanistic studies of estrogen-induced apoptosis. These TPEs all stimulate growth in MCF-7 cells, but unlike the planar estrogens they block estrogen-induced apoptosis in the long-term estrogen-deprived MCF7:5C cells. To define the conformation of the TPE:estrogen receptor (ER) complex, we employed a previously validated assay using the induction of transforming growth factor α (TGFα) mRNA in situ in MDA-MB 231 cells stably transfected with wild-type ER (MC2) or D351G ER mutant (JM6). The assays discriminate ligand fit in the ER based on the extremes of published crystallography of planar estrogens or TPE antiestrogens. We classified the conformation of planar estrogens or angular TPE complexes as "estrogen-like" or "antiestrogen-like" complexes, respectively. The TPE:ER complexes did not readily recruit the coactivator steroid receptor coactivator-3 (SRC3) or ER to the PS2 promoter in MCF-7 and MCF7:5C cells, and molecular modeling showed that they prefer to bind to the ER in an antagonistic fashion, i.e., helix 12 not sealing the ligand binding domain (LBD) effectively, and therefore reduce critical SRC3 binding. The fully activated ER complex with helix 12 sealing the LBD is suggested to be the appropriate trigger to initiate rapid estrogen-induced apoptosis. Source

Tyagi P.,University of the District of Columbia
Journal of Materials Chemistry

Molecular electronics devices have potential to miniaturize the computational devices down to few nm and can be highly versatile. The realization of any molecular electronics device critically depends on the methods of connecting functional molecule(s) to electrical leads. This review mainly focuses on the recently developed versatile multilayer edge molecular electronics device (MEMED) approach. To produce MEMEDs molecular conduction channels are bridged across the ultrathin insulator, along the exposed vertical edges of a tunnel junction. This paper explains how the MEMED approach effectively addresses the major roadblocks encountered in the realization of practical molecular electronics devices. MEMED can be produced by widely available microfabrication tools. The tunnel junction used in a MEMED can have any combination of metallic electrodes. Additionally, the tunnel junction's insulator thickness can be precisely tailored to utilize a vast variety of molecules as a device element. A MEMED approach enables an unprecedented number of control experiments to reveal the true behavior of molecular conduction channels. The tunnel junction used in a MEMED can be characterized before establishing molecular conduction channels. The MEMED approach makes it straightforward to reverse the molecule's effect and then retrieve characteristic of the parent device. This design offers a unique opportunity to transform highly matured magnetic tunnel junctions into futuristic molecular spintronics devices, a potential candidate device for quantum computation. Besides the application in computational devices, MEMED design can also be used for biosensing by enabling the interaction between MEMED's active molecular channels with the target bio-analytes. © The Royal Society of Chemistry 2011. Source

The article applies the Althusserian concept of overdetermination to a contemporary case of urban restructuring in the global South. Since the 2001 invasion of Afghanistan, the international aid industry has been using its capital city, Kabul, as a laboratory and launch pad for liberal policies and programmes to demonstrate that security, economic growth and democracy are mutually reinforcing and can therefore be achieved in conjunction. These interventions have resulted in fundamental structural changes in Kabul's political economy that mimic processes of accumulation by dispossession in the urban global North. Formerly shaped by indigenous political activism and cautious democratic experimentation, Kabul today is a space of accelerated accumulation in the shadows of international peacebuilding. © 2013 Urban Studies Journal Limited. Source

Discover hidden collaborations