353 research outputs found
Carbon nitride as a ligand: edge-site coordination of ReCl(CO)(3)-fragments to g-C3N4
IR spectroscopy and model structural studies show binding of ReCl(CO)3-fragments to carbon nitride (g-C3N4) occurs via κ2 N,N′ bidentate coordination
Integrin-mediated interactions with extracellular matrix proteins for nucleus pulposus cells of the human intervertebral disc.
The extracellular matrix (ECM) of the human intervertebral disc is rich in molecules that interact with cells through integrin-mediated attachments. Porcine nucleus pulposus (NP) cells have been shown to interact with laminin (LM) isoforms LM-111 and LM-511 through select integrins that regulate biosynthesis and cell attachment. Since human NP cells lose many phenotypic characteristics with age, attachment and interaction with the ECM may be altered. Expression of LM-binding integrins was quantified for human NP cells using flow cytometry. The cell-ECM attachment mechanism was determined by quantifying cell attachment to LM-111, LM-511, or type II collagen after functionally blocking specific integrin subunits. Human NP cells express integrins β1, α3, and α5, with over 70% of cells positive for each subunit. Blocking subunit β1 inhibited NP cell attachment to all substrates. Blocking subunits α1, α2, α3, and α5 simultaneously, but not individually, inhibits NP cell attachment to laminins. While integrin α6β1 mediated porcine NP cell attachment to LM-111, we found integrins α3, α5, and β1 instead contributed to human NP cell attachment. These findings identify integrin subunits that may mediate interactions with the ECM for human NP cells and could be used to promote cell attachment, survival, and biosynthesis in cell-based therapeutics
'Thinking like a fish': adaptive strategies for coping with vulnerability and variability emerging from a relational engagement with kob
Based on ethnographic fieldwork amongst a group of commercial handline fishers in the town of Stilbaai in South Africa's southern Cape region, this paper presents a range of flexible, adaptive and evolving strategies through which fishers negotiate constantly shifting variability in weather patterns, fish stocks, fisheries policies, and economic conditions. These variabilities constitute a diverse set of vulnerabilities to which fishers must respond in order to sustain their livelihoods. In this context, the act of 'thinking like a fish' on the part of the fishers provides them with an effective means of adapting to variability and uncertainty. Findings of ethnographic research in 2010-11 suggest that a number of the fishers who participated in the research actively work towards achieving a balance between profit and sustainability. 'Thinking like a fish' is an embodied, interactive way of knowing that emerges from interactions between fishers and fish, offering an ethical and ecological outlook which is a valuable resource for fisheries and conservation management in the region. We suggest that the deeply embodied interactional component of 'thinking like a fish' results from a desire to understand the life world of fish and to think from their perspective in order to more effectively target them while sustaining the species and ecosystem
Synthesis of an orthogonally protected polyhydroxylated cyclopentene from l-Sorbose
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The use of l-sorbose in the synthesis of functionalized cyclopentene derivatives was accomplished. These cyclopentene derivatives are related to those found in naturally occurring jatrophane frameworks and in other bioactive compounds. The formation of allyl α-l-sorbopyranoside was a key synthetic step. Regioselective introduction of protecting groups was followed by the hydrolysis of the allyl glycoside to furnish a fully protected acyclic l-sorbose derivative. This acyclic intermediate was subsequently used to give an orthogonally protected polyhydroxylated cyclopentene, which has potential for further synthesis of bioactive compounds. The protected cyclopentene itself showed a clear cytotoxic activity when tested against a panel of human cancer cell lines (HT29, LS174T, SW620, A549, and HeLa cells).This work was supported by Science Foundation Ireland (grant Nos. 07/IN.1/B966 and 11/TIDA/B2047). The research leading to these results also received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007–2013) under grant agreement number PIEF‐GA‐2011‐299042 and from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 600404 and from MINECO‐FEDER (Bio2013‐40716‐R). IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from MINECO (Government of Spain).Published versio
Delaminated CoAl‐Layered Double Hydroxide@TiO₂ Heterojunction Nanocomposites for Photocatalytic Reduction of CO₂
Photocatalytic reduction offers an attractive route for CO_{2} utilization as a chemical feedstock for solar fuels production but remains challenging due to the poor efficiency, instability, and/or toxicity of current catalyst systems. Delaminated CoAl‐layered double hydroxide nanosheets (LDH‐DS) combined with TiO_{2} nanotubes (NTs) or nanoparticles (NPs) are promising nanocomposite photocatalysts for CO_{2} reduction. Heterojunction formation between visible light absorbing delaminated CoAl nanosheets and UV light absorbing TiO_{2} nanotubes greatly enhances interfacial contact between both high aspect ratio components relative to their bulk counterparts. The resulting synergic interaction confers a significant improvement in photoinduced charge carrier separation, and concomitant aqueous phase CO_{2} photocatalytic reduction, in the absence of a sacrificial hole acceptor. CO productivity for a 3 wt% LDH‐DS@TiO2‐NT nanocomposite of 4.57 µmol g_{cat}^{-1} h^{-1} exhibits a tenfold and fivefold increase over that obtained for individual TiO2 NT and delaminated CoAl‐LDH components respectively and is double that obtained for 3 wt% bulk‐LDH@TiO_{2}-NT and 3 wt% LDH‐DS@TiO2‐NP catalysts. Synthesis of delaminated LDH and metal oxide nanocomposites represents a cost‐effective strategy for aqueous phase CO_{2} reduction
An exploration into the impact of exposure to community violence and hope on children's perceptions of well-being: a South African perspective
The study aims to explore the relationship between exposure to community
violence, hope, and well-being. More specifically, the study aims to ascertain whether
hope is a stronger predictor of well-being than exposure to violence. Stratified
random sampling was used to select a sample of 566 adolescents aged 14–17 years,
from both high violence and low violence areas in Cape Town, South Africa. A
questionnaire consisting of Snyder’s Children’s Hope Scale, the Recent Exposure to
Violence Scale and the KIDSCREEN-52 was used. Data analysis techniques included
descriptive statistics, correlations, and multiple regression. A positive, significant
relationship was found between children’s hope and their well-being. Although
exposure to community violence was found to be significantly correlated with wellbeing,
the relationship was negligible.While exposure to community violence and hope
were found to be significant predictors of well-being, hope emerged as a stronger
predictor of child well-being than exposure to community violence.Department of HE and Training approved lis
Phenotypic Variation and Bistable Switching in Bacteria
Microbial research generally focuses on clonal populations. However, bacterial cells with identical genotypes frequently display different phenotypes under identical conditions. This microbial cell individuality is receiving increasing attention in the literature because of its impact on cellular differentiation, survival under selective conditions, and the interaction of pathogens with their hosts. It is becoming clear that stochasticity in gene expression in conjunction with the architecture of the gene network that underlies the cellular processes can generate phenotypic variation. An important regulatory mechanism is the so-called positive feedback, in which a system reinforces its own response, for instance by stimulating the production of an activator. Bistability is an interesting and relevant phenomenon, in which two distinct subpopulations of cells showing discrete levels of gene expression coexist in a single culture. In this chapter, we address techniques and approaches used to establish phenotypic variation, and relate three well-characterized examples of bistability to the molecular mechanisms that govern these processes, with a focus on positive feedback.
Gene expression of topoisomerase II alpha (TOP2A) by microarray analysis is highly prognostic in estrogen receptor (ER) positive breast cancer
Recruiting to a large-scale physical activity randomised controlled trial – experiences with the gift of hindsight
Background: Recruitment issues continue to impact a large number of trials. Sharing recruitment information is vital to support researchers to accurately predict recruitment and to manage the risk of poor recruitment during study design and implementation. The purpose of this paper is to build on the knowledge available to researchers on recruiting to community based trials.
Methods: A critical commentary of the recruitment challenges encountered during the ‘Booster’ Study, a randomised controlled trial which investigated the effectiveness of a Motivational Interviewing style intervention on the maintenance of physical activity. An overview of recruitment is provided, as well as strategies employed to recruit prospective participants and possible barriers to recruitment.
Results: Two hundred and eighty two people, 47% of the original target, were recruited through mail-outs with secondary recruitment pathways yielding no additional participants. The research team encountered problems re-contacting interested participants and providing study materials in non-English languages. A lower response rate to the mail-out and a greater number of non-contactable participants in the full study compared to the pilot study resulted in a smaller pool of eligible participants from the brief intervention eligible for recruitment into the RCT.
Conclusion: Despite utilising widely accepted recruitment strategies and incorporating new recruitment tactics in response to challenges, the ‘Booster’ study failed to randomise a sufficient number of participants. Recruitment to community based, behavioural interventions may face different challenges than trials based in clinical or primary care pathways. Specific challenges posed by the complexity of the study design and problems with staffing and resources were exacerbated by the need to revise upwards the number of mailed invitations as a result of the pilot study. Researchers should ensure study design is facilitative to recruitment and consider the implications of changing recruitment on the operational aspects of the trial. Where possible the impact of new strategies should be measured, and recruitment successes and challenges shared with those planning similar studies.
The study was a registered controlled trial (ISRCTN56495859 12 Feb 2009; NCT00836459 03 Feb 2009)
KEYWORDS:
Recruitment, Physical Activity, mail-outs, BOOSTER, behaviour maintenance
A murine model of ulcerative colitis: induced with sinusitis-derived superantigen and food allergen
BACKGROUND: The etiology of ulcerative colitis (UC) is to be understood. The basic pathological feature of UC is intestinal chronic inflammation. Superantigen, such as Staphylococcus enterotoxin B (SEB), is reported to compromise intestinal barrier function by increasing epithelial permeability and initiate inflammation in the intestinal mucosa. Inasmuch as anatomic position of the sinus, chronic sinusitis-derived SEB may follow the secretion and to be swallowed down to the gastrointestinal tract and induce lesions to the intestinal mucosa. METHODS: Sinus wash fluid (SWF, containing SEB) was collected from a group of patients with both chronic sinusitis (CS) and UC. A group of mice were sensitized to ovalbumin (OVA) in the presence of SWF. The sensitized mice were challenged with the specific antigen OVA. The inflammatory status of the colonic tissue was determined with histology, serology and electron microscopy. Using horseradish peroxidase (HRP) as a tracer, another group of mice was stimulated with SWF for 2 hours. The HRP activity was detected in the colonic tissue with enzymatic approaches and electron microscopy. RESULTS: Epithelial hyperpermeability in colonic epithelium was induced by stimulating with SWF. The HRP activity in the colonic mucosa was almost 11 times more in the SWF treated group (3.2 ± 0.6 μg/g tissue) than the control group (0.3 ± 0.1 μg/g tissue). Mice were sensitized using a mixture of SWF and OVA (serum OVA-specific IgE was detected with a highest titer as 1:64). Challenge with OVA induced extensive inflammation in the colonic mucosa by showing (1) marked degranulation in mast cells (MC, 46.3 ± 4.5%) and eosinophils (Eo, 55.7 ± 4.2%); (2) inflammatory cell infiltration (MC = 145.2 ± 11.4; Eo = 215.8 ± 12.5; mononuclear cell = 258.4 ± 15.3/mm(2 )tissue); (3) increased MPO activity (12.9 ± 3.2 U/g tissue) and inflammatory scores (1.8 ± 0.3); (4) mucosal surface ulcers; (5) edema in the lamina propria; (6) bacterial translocation and abscess formation in the subepithelial region. CONCLUSION: Introducing Sinusitis-derived SEB-containing SWF to the gastrointestinal tract compromised colonic mucosal barrier function increasing epithelial permeability to luminal macromolecular protein in mice. The SWF facilitated colonic mucosal sensitization to luminal antigen. Multiple challenging the sensitized colonic mucosa with specific antigen OVA induced inflammation, induced a condition similar to human ulcerative colitis
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