Comparing Anti-VEGF Antibodies and Aptamers on Paper Microfluidic-Based Platforms

The field of microfluidics is expanding into what is known as paper microfluidics. This uses a paper platform rather than materials (i.e. PDMS, PMMA) that are commonly used in microfluidics research. Current devices require an expensive manufacturing process and external sources to power the device. Such devices are not practical in low resource environments. As a consequence, it is the goal of this Thesis to develop a three-dimensional, multiplexed assay chip using nitrocellulose membranes. This device comprises of multiple layers of nitrocellulose membranes with defined fluidic channels. The multiple layers are bound together using double backed tape, and imbedded between the layers are conjugate reagents. In the detection region both antibodies and aptamers were evaluated. The fiberglass pad where conjugate reagents would be contained, were initially saturated in dye. As sample was inputted into the three-dimensional chip, the fluid path could be visualized. Without the use of the conjugate pad the chip’s four detection regions showed detection within one minute of one another. However, the addition of this fibrous pad skewed time points dramatically. The hypothesis that a three-dimensional chip could be designed to detect different biomarkers in a multi-analyte sample was satisfied. However, simultaneous detection was only possible if the conjugate pad was either neglected or, possibly, a different material was used. Additionally, current lateral flow assay technologies, another research area that paper microfluidics spawns from, use antibodies in order to capture biomarkers in sample and provide visual signal to the user. However, antibodies are sensitive to denaturation with pH and temperature, whereas aptamers can withstand much more extreme environmental conditions. A two-dimensional nitrocellulose chip was designed to compare antibodies and aptamers as capture reagents to detect VEGF, using colloidal gold as a particle to visualize detection. Both monoclonal and polyclonal anti-VEGF antibodies were used and showed no signal. On the other hand, the anti-VEGF aptamer produced a visual signal when conjugated to biotin on its 5’ end. This data was further validated by a separate project analyzing the binding kinetics of the antibody and the aptamer using Surface Plasmon Resonance. Therefore, the hypothesis that aptamers could be used as a possible capture reagent in a paper microfluidic chip for the detection of VEGF was satisfied

How do co-curricular mentorship programs meet the social-emotional needs of immigrant and refugee youth? A case study from Harrisonburg, Virginia

Immigrant and refugee youth are at greater risk of encountering the following stressors: trauma, acculturation, resettlement, and isolation. If neglected, these stressors can prove detrimental to one’s social-emotional wellbeing. Although a newcomer’s successful adaptation is often measured in terms of their academic success, social-emotional wellbeing and academic achievement are intertwined. Thus, a focus on social-emotional wellness for newcomer students benefits both the students and the school systems. Co-curricular mentorship programs can be utilized by schools to meet the social-emotional needs of their newcomer students. The Peer Leaders Program (PLP) of Harrisonburg, Virginia offers one such approach. Based on trauma-informed peer support research, the Peer Leaders Program uses multi-level mentoring and flexible programming to allow newcomer students to process identity with people who share similar cultures and backgrounds. Through this program, findings suggest that refugee youth process trauma, build confidence, strengthen leadership skills, and become civically engaged with their community

Stratigraphy and palaeoenvironment of the Carboniferous Jurassic Karoo Supergroup in the Lebombo-Tshipise basin

A dissertation presented to the Faculty of Science, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Science. August, 2017The Karoo Supergroup represents a highly complete sedimentary succession that was deposited in several basins throughout southern Africa during the late Palaeozoic and Mesozoic (Carboniferous-Jurassic). While research in the Lebombo-Tshipise Basin of southern Africa has largely focused on lithological description of Karoo sediments or structural features of the basin, little effort has been made to describe the palaeoenvironments recorded in the sediments, or the basin fill’s response to major tectonic or climatic events. To address palaeoenvironmental reconstruction, lithostratigraphic analysis resulted in defining 11 facies associations from the Tshidize, Madzaringwe, Mikembeni, Fripp, Solitude, Elliot and Clarens Formations in the Pafuri sub-basin of the Lebombo-Tshipise Basin. Twenty boreholes drilled in Kruger National Park by the Council for Geoscience in 1979 record largely stable and consistent deposition of the Tshidize, Madzaringwe and Mikembeni Formations during the Permian. The Mikembeni Formation thins dramatically southwards, whereas the overlying Triassic successions tend to wedge out to the east. Late Triassic and Jurassic sediments directly overlie Precambrian basement in the southernmost boreholes. Significant thickness differences between the western and eastern boreholes indicate a large fault, which likely represents a rift shoulder. The palaeoenvironments in this basin are similar to those of the Main Karoo Basin, but quantitative analyses suggest a more humid environment in the Late Triassic Elliot Formation. Sauropodomorph fossils validate assignment of formerly mapped Solitude Formation as actually being the Elliot Formation. Palaeosols in the Elliot are consistent with either Oxisols or Argillisols. Wet desert conditions, evidenced by burrows produced by invertebrate communities, and tectonic activity, suggested by seismites, persist into the Early Jurassic Clarens Formation.MT201

The Identity Issue of the Colonized and the Colonizer in Cloud Nine by Caryl Churchill

One of the significant points in post-colonial literature is identity issues. The analysis of these identity issues should be focused not only on the colonized character but also the colonialist. It is obvious why post-colonial scholars are concerned with the colonized as they are the victims of colonialism. However, the colonizer must also face complex issues of identity when arriving in the colonial place. The purpose of this article is to examine the identity issues undergone by Joshua, the colonial subject, and by Clive, the colonizer, with reference to Cloud Nine by Caryl Churchill in the colonial period. The concept of hybridity by Homi Bhabha can explain the issue of Joshua’s identity since he has “double” portrays of the identity as legacy of colonialism. Bhabha created the terms the “third space” or the “in-between” to describe the condition of the colonized people. Clive as the colonizer used to be a person without particular authority in his own country before arriving to the colonial land. Suddenly, his identity has shifted into someone who has privileges and authority. The colonizer’s identity is not complete without the colonized. The colonized and the colonizer depend on each other. The colonized and the colonizer’s identities will be fragmented if one of them is missing

Assessing Developmental Assessment in Community Colleges

Placement exams are high-stakes assessments that determine many students' college trajectories. The majority of community colleges use placement exams—most often the ACCUPLACER, developed by the College Board, or the COMPASS, developed by ACT, Inc.—to sort students into college-level or developmental education courses in math, reading, and sometimes writing. More than half of entering students at community colleges are placed into developmental education in at least one subject as a result. But the evidence on the predictive validity of these tests is not as strong as many might assume, given the stakes involved—and recent research fails to find evidence that the resulting placements into remediation improve student outcomes. While this has spurred debate about the content and delivery of remedial coursework, it is possible that the assessment process itself may be broken; the debate about remediation policy is incomplete without a fuller understanding of the role of assessment. This Brief examines the role of developmental assessment, the validity of the most common assessments currently in use, and emerging directions in assessment policy and practice. Alternative methods of assessment—particularly those involving multiple measures of student preparedness—seem to have the potential to improve student outcomes, but more research is needed to determine what type of change in assessment and placement policy might improve persistence and graduation rates. The Brief concludes with a discussion of implications for policy and research

Automated Operation of Multiple Payloads on Agile MicroSat (AMS)

The Agile MicroSat (AMS) is a 6U CubeSat designed to operate in very low-Earth orbit (VLEO), an orbit which enables a higher ground resolution given a particular optical sensing aperture. AMS was developed by MIT Lincoln Laboratory in collaboration with Blue Canyon Technologies LLC and Enpulsion GmbH. AMS is hosting three disparate payloads: an indium field effect electric propulsion (FEEP) thruster to change and maintain orbit; a laser demonstration payload called Beacon for adaptive optics experimentation; and a camera payload for visible-spectrum imaging. In order to fully exercise the capability of each payload, the AMS operations team has developed an automated end-to-end processing pipeline which handles experiment scheduling subject to constraints, upload of commands and satellite state estimates to our mission partner BCT, and download and ingest of telemetry for operations planning and the creation of data products. An example product includes a change detection algorithm and image publication workflow, using camera images to detect disaster damage. These payload operation tools have enabled daily interleaved payload operations with minimal manual overhead since the AMS launch on SpaceX\u27s Transporter 5 mission on May 25th, 2022. This paper will describe the architecture of our processing pipeline, mission outcomes, and lessons learned

Solving the mystery of booming sand dunes

Desert booming can be heard after a natural slumping event or during a sand avalanche generated by humans sliding down the slip face of a large dune. The sound is remarkable because it is composed of one dominant audible frequency (70 to 105 Hz) plus several higher harmonics. This study challenges earlier reports that the dunes’ frequency is a function of average grain size by demonstrating through extensive field measurements that the booming frequency results from a natural waveguide associated with the dune. The booming frequency is fixed by the depth of the surficial layer of dry loose sand that is sandwiched between two regions of higher compressional body wave velocity. This letter presents measurements of the booming frequencies, compressional wave velocities, depth of surficial layer, along with an analytical prediction of the frequency based on constructive interference of propagating waves generated by avalanching along the dune surface

Reply to comment by B. Andreotti et al. on "Solving the mystery of booming sand dunes"

This reply addresses three main issues raised in the comment of Andreotti et al. [2008]. First, the turning of ray paths in a granular material does not preclude the propagation of body waves and the resonance condition described by Vriend et al. [2007]. The waveguide model still holds in the dune for the observed velocities, even with a velocity increase with depth as implied by Andreotti et al. [2008]. Secondly, the method of initiation of spontaneous avalanching does not influence the booming frequency. The frequency is independent of the source once sustained booming starts; it depends on the subsurface structure of the dune. Thirdly, if all data points from Vriend et al. [2007] are included in the analysis (and not an average or selection), no correlation is observed between the sustained booming frequency and average particle diameter

Stable incidence rates of tuberculosis (TB) among human immunodeficiency virus (HIV)-negative South African gold miners during a decade of epidemic HIV-associated TB.

During the last decade, annual tuberculosis (TB) case-notification rates increased 4-fold, to >4000 cases/100000 person-years, in the study workforce, among whom prevalence of human immunodeficiency virus (HIV) was 30% in 2000. Three separate cohort studies, totalling 6454 HIV-negative participants, were combined and analyzed for time trends. Observed incidence of TB varied between 962 (1991-1994) and 1589 (1999-2000) cases/100000 person-years (P=.17, test for trend). There was, however, a progressive increase in age, and, for each period, older age was associated with increased incidence rates of TB (P<.001). Having adjusted for age differences, there was no significant association between incidence of TB and calendar period (P=.81, test for trend). Relative to 1991-1994, multivariate-adjusted incidence-rate ratios were 0.94, for 1995-1997, 0.96, for 1998-1999, and 1.05, for 1999-2000. Preventing a secondary epidemic of TB among HIV-negative individuals may be achievable with conventional means, even in settings with a high burden of HIV-associated TB

Palatability of teff grass by horses

Most forages commonly used to feed horses have potential detriments including blister beetles or excessive fiber concentrations. Teff grass (T), a warm-season annual forage, has the potential to be a good alternative for horses because of its lack of observed disorders. Our objective was to compare preference by horses for T harvested under different conditions with that of bermudagrass (B) harvested at two maturities. Six different forages were evaluated: T harvested at the late vegetative stage (TLV), at late bloom but that incurred 33 mm of rainfall between mowing and baling (TLBR), with caryopsis visible (TES), or at soft dough (TSD), and B harvested at late vegetative (BLV) and mid-bloom (BMB) growth stages. Five mature horses were used in a balanced incomplete block design where each horse received a different combination of 4 forages each day for 6 d. The 4 different forages were suspended in hay nets in each corner of each stall, and each hay was offered at 50% of the average daily hay consumption measured during a 12-d adaptation period. Forage preference as measured by individual forage dry matter (DM) consumption (kg and % of total DM consumed across the 4 forages) was greatest (P \u3c 0.05) from TLV followed by BLV. Preference (kg and % of total DM consumed) of BMB was greater (P \u3c 0.05) than that of TMBR, TES, and TSD, which did not differ from each other (P ≥ 0.63). Therefore, within a specific growth stage, horses apparently preferred teff grass, but effects of maturity and rainfall had a more dramatic effect on preference by horses than forage species