93 research outputs found

    Ultrafast Coherent Generation of Hot Electrons Studied via Band-to-Acceptor Luminescence in GaAs

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    The distribution of hot electrons excited with femtosecond laser pulses is studied via spectrally resolved band-to-acceptor luminescence. Our data demonstrate for the first time that the coherent coupling between the laser pulse and the interband polarization strongly influences the initial carrier distribution. The energetic width of carrier generation is broadened due to rapid phase-breaking scattering events. Theoretical results from a Monte Carlo solution of the semiconductor Bloch equations including on the same kinetic level coherent and incoherent phenomena, are in excellent agreement with the experimental data

    The effect of exposure to synthetic pheromone lures on male Zygaena filipendulae mating behaviour: implications for monitoring species of conservation interest

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    Pheromone based monitoring of insects of conservation value has the potential to revolutionise the way in which surveys are carried out. However, due to their effective use in pest management, concerns have been raised about potential negative effects of pheromone exposure on populations of rare insects. The effect of exposure to synthetic pheromone lures on male mating behaviour was examined in laboratory and field conditions using the six spot burnet moth Zygaena filipendulae (Linnaeus, 1758). For the laboratory experiment larvae were collected and cultured separately under controlled conditions. Virgin males were exposed to a synthetic pheromone lure for 24 h; then tested for responsiveness immediately after this exposure, 1 and 24 h later. Control males were tested three times: initially, 1 h later and 24 h later. The time taken for males to detect females, shown by exposure of their anal claspers, and the time taken for males to locate females were recorded. No significant difference was found between the time taken for control and exposed males to detect or locate females, and no significant difference between the proportions of males that successfully located females in exposed and control groups was found. In the field experiment the time males spent in the presence of contained females, both with and without a pheromone lure present, was recorded. Males spent more time in the presence of the females when the pheromone lure was present. Both experiments indicate male Z. filipendulae mating behaviour is not adversely affected by exposure to synthetic pheromone lures

    Identification of female sex pheromone for monitoring the barred tooth striped moth, trichopteryx polycommata, a priority conservation species

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    Pheromone-baited traps can be excellent tools for sensitive detection of insects of conservation concern. Here, identification of the sex pheromone of Trichopteryx polycommata (Denis & SchiffermΓΌller, 1775), an under-recorded UK priority species, is reported. In analyses of extracts of the pheromone glands of female T. polycommata by gas chromatography coupled to electroantennographic recording from the antenna of a male moth, a single active component was detected. This was identified as (Z,Z)-6,9-nonadecadiene (Z,Z6,9-19:H) by comparison of its mass spectrum and retention times with those of the synthetic standard. In a pilot field trial in Kent, UK, T. polycommata males were caught in pheromone traps baited with lures loaded with 1 mg and 2 mg (Z,Z)-6,9-19:H. Optimum lure loading was identified in a further five trials in Kent, Sussex and Lancashire where lures of 0, 0.001, 0.01, 0.1, 1, 2, 5 and 10 mg loadings were tested. Traps baited with 1 to 10 mg of ZZ6,9-19:H caught significantly more T. polycommata than traps baited with 0 mg and 0.001 mg. In a pilot survey of T. polycommata using pheromone lures around Morecambe Bay, UK, T. polycommata males were captured at 122 new sites within the three counties where trials took place, demonstrating the potential of pheromone monitoring to increase knowledge of abundance, distribution and ecology of this elusive species

    Cholesteryl ester transfer protein: at the heart of the action of lipid-modulating therapy with statins, fibrates, niacin, and cholesteryl ester transfer protein inhibitors

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    Subnormal plasma levels of high-density lipoprotein cholesterol (HDL-C) constitute a major cardiovascular risk factor; raising low HDL-C levels may therefore reduce the residual cardiovascular risk that frequently presents in dyslipidaemic subjects despite statin therapy. Cholesteryl ester transfer protein (CETP), a key modulator not only of the intravascular metabolism of HDL and apolipoprotein (apo) A-I but also of triglyceride (TG)-rich particles and low-density lipoprotein (LDL), mediates the transfer of cholesteryl esters from HDL to pro-atherogenic apoB-lipoproteins, with heterotransfer of TG mainly from very low-density lipoprotein to HDL. Cholesteryl ester transfer protein activity is elevated in the dyslipidaemias of metabolic disease involving insulin resistance and moderate to marked hypertriglyceridaemia, and is intimately associated with premature atherosclerosis and high cardiovascular risk. Cholesteryl ester transfer protein inhibition therefore presents a preferential target for elevation of HDL-C and reduction in atherosclerosis. This review appraises recent evidence for a central role of CETP in the action of current lipid-modulating agents with HDL-raising potential, i.e. statins, fibrates, and niacin, and compares their mechanisms of action with those of pharmacological agents under development which directly inhibit CETP. New CETP inhibitors, such as dalcetrapib and anacetrapib, are targeted to normalize HDL/apoA-I levels and anti-atherogenic activities of HDL particles. Further studies of these CETP inhibitors, in particular in long-term, large-scale outcome trials, will provide essential information on their safety and efficacy in reducing residual cardiovascular risk

    Allergic rhinitis : review of the diagnosis and management : South African Allergic Rhinitis Working Group

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    DATA AVAILABILITY : The authors confirm that the data supporting the findings of this study are available within the article.BACKGROUND : Allergic rhinitis (AR) has a significant impact on the community as a whole with regard to quality of life and its relationship to allergic multi-morbidities. Appropriate diagnosis, treatment and review of the efficacy of interventions can ameliorate these effects. Yet, the importance of AR is often overlooked, and appropriate therapy is neglected. The availability of effective medications and knowledge as to management are often lacking in both public and private health systems. METHODS : This review is based on a comprehensive literature search and detailed discussions by the South African Allergic Rhinitis Working Group (SAARWG). RESULTS : The working group provided up-to-date recommendations on the epidemiology, pathology, diagnosis and management of AR, appropriate to the South African setting. CONCLUSION : Allergic rhinitis causes significant, often unappreciated, morbidity. It is a complex disease related to an inflammatory response to environmental allergens. Therapy involves education, evaluation of allergen sensitisation, pharmacological treatment, allergen immunotherapy (AIT) and evaluation of the success of interventions. Regular use of saline; the important role of intranasal corticosteroids, including those combined with topical antihistamines and reduction in the use of systemic steroids are key. Practitioners should have a thorough knowledge of associated morbidities and the need for specialist referral. CONTRIBUTION : This review summarises the latest developments in the diagnosis and management of AR such that it is a resource that allows easy access for family practitioners and specialists alike.https://www.safpj.co.zaam2024ImmunologyOtorhinolaryngologyPaediatrics and Child HealthSDG-03:Good heatlh and well-bein

    A Common CNR1 (Cannabinoid Receptor 1) Haplotype Attenuates the Decrease in HDL Cholesterol That Typically Accompanies Weight Gain

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    We have previously shown that genetic variability in CNR1 is associated with low HDL dyslipidemia in a multigenerational obesity study cohort of Northern European descent (209 families, median β€Š=β€Š10 individuals per pedigree). In order to assess the impact of CNR1 variability on the development of dyslipidemia in the community, we genotyped this locus in all subjects with class III obesity (body mass index >40 kg/m2) participating in a population-based biobank of similar ancestry. Twenty-two haplotype tagging SNPs, capturing the entire CNR1 gene locus plus 15 kb upstream and 5 kb downstream, were genotyped and tested for association with clinical lipid data. This biobank contains data from 645 morbidly obese study subjects. In these subjects, a common CNR1 haplotype (H3, frequency 21.1%) is associated with fasting TG and HDL cholesterol levels (pβ€Š=β€Š0.031 for logTG; pβ€Š=β€Š0.038 for HDL-C; pβ€Š=β€Š0.00376 for log[TG/HDL-C]). The strength of this relationship increases when the data are adjusted for age, gender, body mass index, diet and physical activity. Mean TG levels were 160Β±70, 155Β±70, and 120Β±60 mg/dL for subjects with 0, 1, and 2 copies of the H3 haplotype. Mean HDL-C levels were 45Β±10, 47Β±10, and 48Β±9 mg/dL, respectively. The H3 CNR1 haplotype appears to exert a protective effect against development of obesity-related dyslipidemia

    Symbiotic Associations in the Phenotypically-Diverse Brown Alga Saccharina japonica

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    The brown alga Saccharina japonica (Areschoug) Lane, Mayes, Druehl et Saunders is a highly polymorphic representative of the family Laminariaceae, inhabiting the northwest Pacific region. We have obtained 16S rRNA sequence data in symbiont microorganisms of the typical form (TYP) of S. japonica and its common morphological varieties, known as β€œlongipes” (LON) and β€œshallow-water” (SHA), which show contrasting bathymetric distribution and sharp morphological, life history traits, and ecological differences. Phylogenetic analysis of the 16S rRNA sequences shows that the microbial communities are significantly different in the three forms studied and consist of mosaic sets of common and form-specific bacterial lineages. The divergence in bacterial composition is substantial between the TYP and LON forms in spite of their high genetic similarity. The symbiont distribution in the S. japonica forms and in three other laminarialean species is not related to the depth or locality of the algae settlements. Combined with our previous results on symbiont associations in sea urchins and taking into account the highly specific character of bacteria-algae associations, we propose that the TYP and LON forms may represent incipient species passing through initial steps of reproductive isolation. We suggest that phenotype differences between genetically similar forms may be caused by host-symbiont interactions that may be a general feature of evolution in algae and other eukaryote organisms. Bacterial symbionts could serve as sensitive markers to distinguish genetically similar algae forms and also as possible growth-promoting inductors to increase algae productivity

    Knowledge-Driven Multi-Locus Analysis Reveals Gene-Gene Interactions Influencing HDL Cholesterol Level in Two Independent EMR-Linked Biobanks

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    Genome-wide association studies (GWAS) are routinely being used to examine the genetic contribution to complex human traits, such as high-density lipoprotein cholesterol (HDL-C). Although HDL-C levels are highly heritable (h2∼0.7), the genetic determinants identified through GWAS contribute to a small fraction of the variance in this trait. Reasons for this discrepancy may include rare variants, structural variants, gene-environment (GxE) interactions, and gene-gene (GxG) interactions. Clinical practice-based biobanks now allow investigators to address these challenges by conducting GWAS in the context of comprehensive electronic medical records (EMRs). Here we apply an EMR-based phenotyping approach, within the context of routine care, to replicate several known associations between HDL-C and previously characterized genetic variants: CETP (rs3764261, pβ€Š=β€Š1.22e-25), LIPC (rs11855284, pβ€Š=β€Š3.92e-14), LPL (rs12678919, pβ€Š=β€Š1.99e-7), and the APOA1/C3/A4/A5 locus (rs964184, pβ€Š=β€Š1.06e-5), all adjusted for age, gender, body mass index (BMI), and smoking status. By using a novel approach which censors data based on relevant co-morbidities and lipid modifying medications to construct a more rigorous HDL-C phenotype, we identified an association between HDL-C and TRIB1, a gene which previously resisted identification in studies with larger sample sizes. Through the application of additional analytical strategies incorporating biological knowledge, we further identified 11 significant GxG interaction models in our discovery cohort, 8 of which show evidence of replication in a second biobank cohort. The strongest predictive model included a pairwise interaction between LPL (which modulates the incorporation of triglyceride into HDL) and ABCA1 (which modulates the incorporation of free cholesterol into HDL). These results demonstrate that gene-gene interactions modulate complex human traits, including HDL cholesterol
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