128 research outputs found

    F.T.I.R. and Rheological studies of surfactant adsorption onto silica

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    The adsorption of four surfactants at the silica-toluene interface have been investigated by Fourier-transform infrared - attenuated total reflection (FTIR-ATR) spectroscopy. Specifically, hexadecylamine, 1,12-diaminododecane, didecylamine and sorbitan monopalmitate were studied. The silica surface for the spectroscopic experiments was provided by the native oxide layer on a silicon ATR prism. In order to study the CH(_2) stretching vibrations, the solvent was fully deuterated. Careful calibration of the ATR experiment enabled the contribution to the ATR spectrum made by adsorbed species to be calculated. The surface excess concentration of the amines were calculated over a range of bulk solution conentrations, enabling adsorption isotherms to be constructed. The use of polarized radiation allowed the orientation of the molecules within the adsorbed layer to be studied. The adsorbed layer of hexadecylamine showed some ordering of the aliphatic chains. There is some spectral evidence that the chains in the adsorbed layer of 1,12- diaminododecane adopt a 'looped' configuration. The effect of adsorbed layers of the molecules listed above upon the rheological behaviour of Aerosil 200 dispersions in toluene was investigated. Differences in the rheological behaviour of these dispersions have been correlated to differences in adsorbed layer structure as determined by FTIR-ATR. Due to differences in the Aerosil and ATR surface these correlations must be treated cautiously

    Female Entrepreneurship in China: Opportunity- or Necessity-Based?

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    The paper investigates the inequalities within entrepreneurship which are hindering Chinese socio-economic development. We take an institutionalist and gender-based approach. We establish the relationship between entrepreneurship and economic development and create a historical framework from which we examine contemporary female entrepreneurship. We find that females in China often engage in entrepreneurship in the informal sector, where average income is lower. Females are more likely than men to engage in necessity-based entrepreneurship rather than opportunity-based entrepreneurship in China. Therefore, the overall increase in female entrepreneurship in China in recent years does not necessarily imply improvement in living standards for those women. The paper demonstrates that different classes of entrepreneurs face different barriers, and that females need targeted assistance so that the gender gap in entrepreneurship can be reduced. Government should take responsibility for deconstructing social and cultural barriers to women through policy initiatives, as well as promoting women\u27s entrepreneurial training and capital formation. There is also a key role for the non-governmental sector and international organisations to play in educating government, businesses, and workers, as well as pressuring and/or coordinating them where needed

    TRPV4 and KCa functionally couple as osmosensors in the PVN

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    BACKGROUND AND PURPOSE: Transient receptor potential vanilloid type 4 (TRPV4) and calcium-activated potassium channels (KCa ) mediate osmosensing in many tissues. Both TRPV4 and KCa channels are found in the paraventricular nucleus (PVN) of the hypothalamus, an area critical for sympathetic control of cardiovascular and renal function. Here, we have investigated whether TRPV4 channels functionally couple to KCa channels to mediate osmosensing in PVN parvocellular neurones and have characterized, pharmacologically, the subtype of KCa channel involved. EXPERIMENTAL APPROACH: We investigated osmosensing roles for TRPV4 and KCa channels in parvocellular PVN neurones using cell-attached and whole-cell electrophysiology in mouse brain slices and rat isolated PVN neurons. Intracellular Ca(2+) was recorded using Fura-2AM. The system was modelled in the NEURON simulation environment. KEY RESULTS: Hypotonic saline reduced action current frequency in hypothalamic slices; a response mimicked by TRPV4 channel agonists 4αPDD (1 μM) and GSK1016790A (100 nM), and blocked by inhibitors of either TRPV4 channels (RN1734 (5 μM) and HC067047 (300 nM) or the low-conductance calcium-activated potassium (SK) channel (UCL-1684 30 nM); iberiotoxin and TRAM-34 had no effect. Our model was compatible with coupling between TRPV4 and KCa channels, predicting the presence of positive and negative feedback loops. These predictions were verified using isolated PVN neurons. Both hypotonic challenge and 4αPDD increased intracellular Ca(2+) and UCL-1684 reduced the action of hypotonic challenge. CONCLUSIONS AND IMPLICATIONS: There was functional coupling between TRPV4 and SK channels in parvocellular neurones. This mechanism contributes to osmosensing in the PVN and may provide a novel pharmacological target for the cardiovascular or renal systems

    Epitope mapping of antibodies induced with a conserved rhinovirus protein generating protective anti-rhinovirus immunity

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    Human rhinovirus (RV) infections are the principle cause of common colds and precipitate asthma and chronic obstructive pulmonary disease (COPD) exacerbations. Currently there is no vaccine for RV which is largely due to the existence of ~160 serotypes/strains. We demonstrated previously that immunising mice with highly conserved VP4 and VP2 regions of the RV polyprotein (RV-A16 VP0) generated cross-reactive immunity to RV in vivo. The current study investigated and mapped the epitopes of RV-A16 VP0 that are targets for antibodies in serum samples from VP0 immunisation and RV challenge studies in mice. Recombinant capsid proteins, peptide pools and individual peptides spanning the immunogen sequence (RV-A16 VP0) were assessed for IgG binding sites to identify epitopes. We found that peptide pools covering the C-terminus of VP4, the N-terminus of VP2 and the neutralising NIm-II site within VP2 were bound by serum IgG from immunised mice. The NIm-II site peptide pool blocked IgG binding to the immunogen RV-A16 VP0 and individual peptides within the pool binding IgG were further mapped. Thus, we have identified immunodominant epitopes of RV vaccine candidate RV-A16 VP0, noting that strong IgG binding antibodies were observed that target a key neutralising epitope that is highly variable amongst RV serotypes

    High Temperature Treatment of Diamond Particles Toward Enhancement of Their Quantum Properties

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    Fluorescence of the negatively charged nitrogen-vacancy (NV-) center of diamond is sensitive to external electromagnetic fields, lattice strain, and temperature due to the unique triplet configuration of its spin states. Their use in particulate diamond allows for the possibility of localized sensing and magnetic-contrast-based differential imaging in complex environments with high fluorescent background. However, current methods of NV(-)production in diamond particles are accompanied by the formation of a large number of parasitic defects and lattice distortions resulting in deterioration of the NV(-)performance. Therefore, there are significant efforts to improve the quantum properties of diamond particles to advance the field. Recently it was shown that rapid thermal annealing (RTA) at temperatures much exceeding the standard temperatures used for NV(-)production can efficiently eliminate parasitic paramagnetic impurities and, as a result, by an order of magnitude improve the degree of hyperpolarization of(13)C via polarization transfer from optically polarized NV(-)centers in micron-sized particles. Here, we demonstrate that RTA also improves the maximum achievable magnetic modulation of NV(-)fluorescence in micron-sized diamond by about 4x over conventionally produced diamond particles endowed with NV-. This advancement can continue to bridge the pathway toward developing nano-sized diamond with improved qualities for quantum sensing and imaging

    The power of names: radical identities in the Reformation Era

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    Book synopsis: This volume of essays explores the themes of radicalism and dissent within Protestantism. The comparisons highlight the contingent nature of particular settlements and narratives, and reveal the extent to which the definition of religious radicalism was dependent upon immediate context and show that radicalism and dissent were truly transnational phenomena. The historiography of the so-called radical reformation has been unduly shaped by the hostile categories imposed by mainstream or magisterial reformers during the sixteenth and seventeenth centuries. This volume argues that scholars should adopt an open-ended understanding of evangelical reform, and recognize that the boundaries between radicalism and its opposite were not always firmly drawn. The distinction between the two is an inheritance of the Lutheran Reformation of the 1520s, which shaped not only the later course of the Reformation in the Holy Roman Empire but also attitudes towards and writings on religious dissent in the Netherlands and England. Radical critique is immanent within mainstream Protestantism, in a faith that emphasizes the power of the gospel with its unrelenting demands

    Rapid Implementation of an Integrated Large-Scale HIV Counseling and Testing, Malaria, and Diarrhea Prevention Campaign in Rural Kenya

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    BACKGROUND: Integrated disease prevention in low resource settings can increase coverage, equity and efficiency in controlling high burden infectious diseases. A public-private partnership with the Ministry of Health, CDC, Vestergaard Frandsen and CHF International implemented a one-week integrated multi-disease prevention campaign. METHOD: Residents of Lurambi, Western Kenya were eligible for participation. The aim was to offer services to at least 80% of those aged 15-49. 31 temporary sites in strategically dispersed locations offered: HIV counseling and testing, 60 male condoms, an insecticide-treated bednet, a household water filter for women or an individual filter for men, and for those testing positive, a 3-month supply of cotrimoxazole and referral for follow-up care and treatment. FINDINGS: Over 7 days, 47,311 people attended the campaign with a 96% uptake of the multi-disease preventive package. Of these, 99.7% were tested for HIV (87% in the target 15-49 age group); 80% had previously never tested. 4% of those tested were positive, 61% were women (5% of women and 3% of men), 6% had median CD4 counts of 541 cell/µL (IQR; 356, 754). 386 certified counselors attended to an average 17 participants per day, consistent with recommended national figures for mass campaigns. Among women, HIV infection varied by age, and was more likely with an ended marriage (e.g. widowed vs. never married, OR.3.91; 95% CI. 2.87-5.34), and lack of occupation. In men, quantitatively stronger relationships were found (e.g. widowed vs. never married, OR.7.0; 95% CI. 3.5-13.9). Always using condoms with a non-steady partner was more common among HIV-infected women participants who knew their status compared to those who did not (OR.5.4 95% CI. 2.3-12.8). CONCLUSION: Through integrated campaigns it is feasible to efficiently cover large proportions of eligible adults in rural underserved communities with multiple disease preventive services simultaneously achieving various national and international health development goals

    Red Is Not a Proxy Signal for Female Genitalia in Humans

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    Red is a colour that induces physiological and psychological effects in humans, affecting competitive and sporting success, signalling and enhancing male social dominance. The colour is also associated with increased sexual attractiveness, such that women associated with red objects or contexts are regarded as more desirable. It has been proposed that human males have a biological predisposition towards the colour red such that it is ‘sexually salient’. This hypothesis argues that women use the colour red to announce impending ovulation and sexual proceptivity, with this functioning as a proxy signal for genital colour, and that men show increased attraction in consequence. In the first test of this hypothesis, we show that contrary to the hypothesis, heterosexual men did not prefer redder female genitalia and, by extension, that red is not a proxy signal for genital colour. We found a relative preference for pinker genital images with redder genitalia rated significantly less sexually attractive. This effect was independent of raters' prior sexual experience and variation in female genital morphology. Our results refute the hypothesis that men's attraction to red is linked to an implied relationship to genital colour and women's signalling of fertility and sexual proceptivity

    Exploiting genomics for antimicrobial resistance surveillance at One Health interfaces.

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    The intersection of human, animal, and ecosystem health at One Health interfaces is recognised as being of key importance in the evolution and spread of antimicrobial resistance (AMR) and represents an important, and yet rarely realised opportunity to undertake vital AMR surveillance. A working group of international experts in pathogen genomics, AMR, and One Health convened to take part in a workshop series and online consultation focused on the opportunities and challenges facing genomic AMR surveillance in a range of settings. Here we outline the working group's discussion of the potential utility, advantages of, and barriers to, the implementation of genomic AMR surveillance at One Health interfaces and propose a series of recommendations for addressing these challenges. Embedding AMR surveillance at One Health interfaces will require the development of clear beneficial use cases, especially in low-income and middle-income countries. Evidence of directionality, risks to human and animal health, and potential trade implications were also identified by the working group as key issues. Addressing these challenges will be vital to enable genomic surveillance technology to reach its full potential for assessing the risk of transmission of AMR between the environment, animals, and humans at One Health interfaces.

    Genomics for antimicrobial resistance surveillance to support infection prevention and control in health-care facilities

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    Integration of genomic technologies into routine antimicrobial resistance (AMR) surveillance in health-care facilities has the potential to generate rapid, actionable information for patient management and inform infection prevention and control measures in near real time. However, substantial challenges limit the implementation of genomics for AMR surveillance in clinical settings. Through a workshop series and online consultation, international experts from across the AMR and pathogen genomics fields convened to review the evidence base underpinning the use of genomics for AMR surveillance in a range of settings. Here, we summarise the identified challenges and potential benefits of genomic AMR surveillance in health-care settings, and outline the recommendations of the working group to realise this potential. These recommendations include the definition of viable and cost-effective use cases for genomic AMR surveillance, strengthening training competencies (particularly in bioinformatics), and building capacity at local, national, and regional levels using hub and spoke models
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