96 research outputs found
Involvement of stakeholders in the water quality monitoring and surveillance system: The case of Mzingwane Catchment
"Healing a Part of My Soul": A Qualitative Case Study Exploring Cultural Centers and Student Achievement in Higher Education
The number of women, Students of Color, and LGBTQIA+ students enrolled in institutions of higher education have increased significantly over the past several decades (Hanson, 2021; National Center for Education Statistics, 2010). Though gaps in higher education degree completion have improved in recent years, gains for Students of Color have not kept pace with their white peers (Pendakur, 2016). Minoritized students continue to face disparate experiences and outcomes on college campuses (Bickford, 2019; Hurtado & Carter, 1997; Hussain & Jones, 2021; Johnson et al., 2007; Kelly & Torres, 2006; Vaccaro & Newman, 2017). Recent literature has suggested universities need to assume greater responsibility in welcoming and supporting minoritized students (Dowd et al., 2011; Museus, 2014; Oseguera & Rhee, 2009). Focusing on sense of belonging (Hurtado & Carter, 1997; Hussain & Jones, 2021), employing equity models of student success (Harper, 2012; Museus, 2014; Tatum, 2007; Yosso, 2005), and encouraging diverse forms of epistemology are all key strategies to supporting minoritized students (Hill Collins, 2009; hooks, 1994; Tanaka, 2002). This dissertation explored the ways in which campus cultural centers are spaces that support positive subcultures and can contribute meaningfully to closing gaps in graduation rates. Cultural centers are rare examples of "third-spaces" where students' academic and cocurricular experiences are bridged in ways that are culturally specific and affirming (Gutiérrez, 1995; Patton, 2011; Sanders, 2016; Shuford, 2011). This study used qualitative methods to understand the ways in which engagement in cultural centers supported student achievement at one specific institution of higher education. Data collected from semistructured interviews from juniors and seniors at California University (a pseudonym) and a focus group with professional staff explored the impact of cultural center spaces on student achievement
Do schistosome vaccine trials in mice have an intrinsic flaw that generates spurious protection data?
The laboratory mouse has been widely used to test the efficacy of schistosome vaccines and a long list of candidates has emerged from this work, many of them abundant internal proteins. These antigens do not have an additive effect when co-administered, or delivered as SWAP homogenate, a quarter of which comprises multiple candidates; the observed protection has an apparent ceiling of 40–50 %. We contend that the low level of maturation of penetrating cercariae (~32 % for Schistosoma mansoni) is a major limitation of the model since 68/100 parasites fail to mature in naïve mice due to natural causes. The pulmonary capillary bed is the obstacle encountered by schistosomula en route to the portal system. The fragility of pulmonary capillaries and their susceptibility to a cytokine-induced vascular leak syndrome have been documented. During lung transit schistosomula burst into the alveolar spaces, and possess only a limited capacity to re-enter tissues. The acquired immunity elicited by the radiation attenuated (RA) cercarial vaccine relies on a pulmonary inflammatory response, involving cytokines such as IFNγ and TNFα, to deflect additional parasites into the alveoli. A principal difference between antigen vaccine protocols and the RA vaccine is the short interval between the last antigen boost and cercarial challenge of mice (often two weeks). Thus, after antigen vaccination, challenge parasites will reach the lungs when both activated T cells and cytokine levels are maximal in the circulation. We propose that “protection” in this situation is the result of physiological effects on the pulmonary blood vessels, increasing the proportion of parasites that enter the alveoli. This hypothesis will explain why internal antigens, which are unlikely to interact with the immune response in a living schistosomulum, plus a variety of heterologous proteins, can reduce the level of maturation in a non-antigen-specific way. These proteins are “successful” precisely because they have not been selected for immunological silence. The same arguments apply to vaccine experiments with S. japonicum in the mouse model; this schistosome species seems a more robust parasite, even harder to eliminate by acquired immune responses. We propose a number of ways in which our conclusions may be tested
Genomic and Proteomic Studies on the Mode of Action of Oxaboroles against the African Trypanosome
SCYX-7158, an oxaborole, is currently in Phase I clinical trials for the treatment of human African trypanosomiasis. Here we investigate possible modes of action against Trypanosoma brucei using orthogonal chemo-proteomic and genomic approaches. SILAC-based proteomic studies using an oxaborole analogue immobilised onto a resin was used either in competition with a soluble oxaborole or an immobilised inactive control to identify thirteen proteins common to both strategies. Cell-cycle analysis of cells incubated with sub-lethal concentrations of an oxaborole identified a subtle but significant accumulation of G2 and >G2 cells. Given the possibility of compromised DNA fidelity, we investigated long-term exposure of T. brucei to oxaboroles by generating resistant cell lines in vitro. Resistance proved more difficult to generate than for drugs currently used in the field, and in one of our three cell lines was unstable. Whole-genome sequencing of the resistant cell lines revealed single nucleotide polymorphisms in 66 genes and several large-scale genomic aberrations. The absence of a simple consistent mechanism among resistant cell lines and the diverse list of binding partners from the proteomic studies suggest a degree of polypharmacology that should reduce the risk of resistance to this compound class emerging in the field. The combined genetic and chemical biology approaches have provided lists of candidates to be investigated for more detailed information on the mode of action of this promising new drug clas
One Scaffold, Three Binding Modes: Novel and Selective Pteridine Reductase 1 Inhibitors Derived from Fragment Hits Discovered by Virtual Screening†
The enzyme pteridine reductase 1 (PTR1) is a potential target for new compounds to treat human African trypanosomiasis. A virtual screening campaign for fragments inhibiting PTR1 was carried out. Two novel chemical series were identified containing aminobenzothiazole and aminobenzimidazole scaffolds, respectively. One of the hits (2-amino-6-chloro-benzimidazole) was subjected to crystal structure analysis and a high resolution crystal structure in complex with PTR1 was obtained, confirming the predicted binding mode. However, the crystal structures of two analogues (2-amino-benzimidazole and 1-(3,4-dichloro-benzyl)-2-amino-benzimidazole) in complex with PTR1 revealed two alternative binding modes. In these complexes, previously unobserved protein movements and water-mediated protein-ligand contacts occurred, which prohibited a correct prediction of the binding modes. On the basis of the alternative bindingmode of 1-(3,4-dichloro-benzyl)-2-amino-benzimidazole, derivatives were designed and selective PTR1 inhibitors with low nanomolar potency and favorable physicochemical properties were obtained
Hepatitis B virus infection in post-vaccination South Africa : occult HBV infection and circulating surface gene variants
No abstract availableNational Health Laboratory Services (NHLS)Research Trust [grant number: GRANT004_94329] and the Poliomyelitis Research Foundation (PRF) [grant number: 11/74 (MSc)].http://www.elsevier.com/locate/jcvhb201
Identification of a 4-fluorobenzyl L-valinate amide benzoxaborole (AN11736) as a potential development candidate for the treatment of Animal African Trypanosomiasis (AAT)
Novel l-valinate amide benzoxaboroles and analogues were designed and synthesized for a structure-activity-relationship (SAR) investigation to optimize the growth inhibitory activity against Trypanosoma congolense (T. congolense) and Trypanosoma vivax (T. vivax) parasites. The study identified 4-fluorobenzyl (1-hydroxy-7-methyl-1,3-dihydrobenzo[c][1,2]oxaborole-6-carbonyl)-l-valinate (5, AN11736), which showed IC50 values of 0.15 nM against T. congolense and 1.3 nM against T. vivax, and demonstrated 100% efficacy with a single dose of 10 mg/kg against both T. congolense and T. vivax in mouse models of infection (IP dosing) and in the target animal, cattle, dosed intramuscularly. AN11736 has been advanced to early development studies
Epidemiological survey of Lutzomyia longipalpis infected by Leishmania infantum in an endemic area of Brazil
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