Potential Anti-cancer and Anti-bacterial Activities of Philippine Echinoderm Extracts

In high-throughput search for bioactive compounds under resource-limited settings from Philippine echinoderms, the aqueous, methanol, chloroform and hexane extracts of seven Philippine echinoderms namely Holothuria nobilis (sea cucumber), Bohadscia marmorata (sea cucumber), Stichopus chloronatus (sea cucumber), Holothuria axiologa (sea cucumber), Linckia laevigata (starfish), Oreaster nodusus (starfish) and Ophiocoma ochoenleinii (brittle star) were screened for antitumor and antibacterial activity. Antitumor activity was determined using brine shrimp lethality assay while antibacterial assay was performed using turbidimetric method. Both assays utilized 96-well microtiter plates to facilitate speed and ease in screening. The chloroform extract of H. nobilis gave a positive result on antitumor activity while almost all sample extracts showed antibacterial activity against E. coli

Direct simulation of ion beam induced stressing and amorphization of silicon

Using molecular dynamics (MD) simulation, we investigate the mechanical response of silicon to high dose ion-irradiation. We employ a realistic and efficient model to directly simulate ion beam induced amorphization. Structural properties of the amorphized sample are compared with experimental data and results of other simulation studies. We find the behavior of the irradiated material is related to the rate at which it can relax. Depending upon the ability to deform, we observe either the generation of a high compressive stress and subsequent expansion of the material, or generation of tensile stress and densification. We note that statistical material properties, such as radial distribution functions are not sufficient to differentiate between different densities of amorphous samples. For any reasonable deformation rate, we observe an expansion of the target upon amorphization in agreement with experimental observations. This is in contrast to simulations of quenching which usually result in denser structures relative to crystalline Si. We conclude that although there is substantial agreement between experimental measurements and most simulation results, the amorphous structures being investigated may have fundamental differences; the difference in density can be attributed to local defects within the amorphous network. Finally we show that annealing simulations of our amorphized samples can lead to a reduction of high energy local defects without a large scale rearrangement of the amorphous network. This supports the proposal that defects in amorphous silicon are analogous to those in crystalline silicon.Comment: 13 pages, 12 figure

Priority sites for wildfowl conservation in Mexico

A set of priority sites for wildfowl conservation in Mexico was determined using contemporary count data (1991–2000) from the U.S. Fish & Wildlife Service mid-winter surveys. We used a complementarity approach implemented through linear integer programming that addresses particular conservation concerns for every species included in the analysis and large fluctuations in numbers through time. A set of 31 priority sites was identified, which held more than 69% of the mid-winter count total in Mexico during all surveyed years. Six sites were in the northern highlands, 12 in the central highlands, six on the Gulf of Mexico coast and seven on the upper Pacific coast. Twenty-two sites from the priority set have previously been identified as qualifying for designation as wetlands of international importance under the Ramsar Convention and 20 sites are classified as Important Areas for Bird Conservation in Mexico. The information presented here provides an accountable, spatially-explicit, numerical basis for ongoing conservation planning efforts in Mexico, which can be used to improve existing wildfowl conservation networks in the country and can also be useful for conservation planning exercises elsewhere

Community Colleges and COVID-19: An Exploration of Challenges and Inequities

COVID-19 drastically changed many aspects of life in the U.S. and most certainly changed standard operating procedures in higher education. Moving all classes completely online created numerous challenges not only for students, but also for faculty. For students, these challenges included issues related to physical and mental health, job loss, and caregiving, as well as access to internet and even access to a home computer. Faculty also faced challenges. For example, many colleges and universities rely on adjunct faculty who are compensated on a course-by-course basis. Although most institutions provided faculty development sessions to make a smooth transition to online teaching, adjunct faculty were not necessarily invited to participate and, when they were, they were not compensated for time spent in these sessions or the additional work incurred to transition and teach in the online environment. This essay explores how community college students and faculty in the basic course responded to the COVID-19 crisis. Specifically, we discuss issues of employment, family responsibilities, and the digital divide as they reveal systemic inequities in the college setting, as well as in society

Identification of Class I HLA T Cell Control Epitopes for West Nile Virus

The recent West Nile virus (WNV) outbreak in the United States underscores the importance of understanding human immune responses to this pathogen. Via the presentation of viral peptide ligands at the cell surface, class I HLA mediate the T cell recognition and killing of WNV infected cells. At this time, there are two key unknowns in regards to understanding protective T cell immunity: 1) the number of viral ligands presented by the HLA of infected cells, and 2) the distribution of T cell responses to these available HLA/viral complexes. Here, comparative mass spectroscopy was applied to determine the number of WNV peptides presented by the HLA-A*11:01 of infected cells after which T cell responses to these HLA/WNV complexes were assessed. Six viral peptides derived from capsid, NS3, NS4b, and NS5 were presented. When T cells from infected individuals were tested for reactivity to these six viral ligands, polyfunctional T cells were focused on the GTL9 WNV capsid peptide, ligands from NS3, NS4b, and NS5 were less immunogenic, and two ligands were largely inert, demonstrating that class I HLA reduce the WNV polyprotein to a handful of immune targets and that polyfunctional T cells recognize infections by zeroing in on particular HLA/WNV epitopes. Such dominant HLA/peptide epitopes are poised to drive the development of WNV vaccines that elicit protective T cells as well as providing key antigens for immunoassays that establish correlates of viral immunity. © 2013 Kaabinejadian et al