165 research outputs found

    MALDI-MS at the Ingenieurschule Burgdorf: The Technique, Some Applications and Expected Benefits for the Education in Modern Analytical Chemistry

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    Analytical chemistry is changing rapidly, new methods are developed and introduced in the analytical laboratories. Parallel to this progress, the chemical industry is undergoing pronounced changes: it is focusing more and more on the life sciences.Consequently, the importance of analytical biochemistry is increasing.The educational system has to keep pace with these developments and has to integrate the new methods, which are or will be tools in analytical laboratories, into the analytical chemistry courses.Therefore, we were looking for an appropriate method which would allow us to face these challenges in analytical education at the Ingenieurschule (college of engineering) Burgdorf. With the recent acquisition of a matrix-assisted laser desorption mass spectrometer (MALDI-MS), a new analytical technique which has the potential to fulfill our requirements can be offered to the chemistry students.This contribution presents some analytical applications such as the sequence analysis of a modified oligonucleotide, the characterization of a non-covalently bound antigen-antibody complex as well as the analysis of a synthetic polymer and copolymer. Projects how to implement the method in the analytical chemistry course and the expected benefits for the students are discussed

    Health Problems After Travel to Developing Countries

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    Travelers to developing countries participated in a follow-up study of the health risks associated with short (less than three months) visits to these nations. Travelers to the Greek or Canary Islands served as a control cohort. Participants completed a questionnaire to elicit information regarding pretravel vaccinations, malaria prophylaxis, and health problems during and after their journey. Relevant infections were confirmed by the respondent's personal physician. The questionnaire was completed by 10,524 travelers; the answer rate was 73.8%. After a visit to developing countries, 15% of the travelers reported health problems, 8% consulted a doctor, and 3% were unable to work for an average of 15 days. The incidence of infection per month abroad was as follows: giardiasis, 7/1,000; amebiasis, 4/1,000; hepatitis, 4/1,000; gonorrhea, 3/1,000; and malaria, helminthiases, or syphilis, <1/1,000. There were no cases of typhoid fever or choler

    Health Problems After Travel to Developing Countries

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    Travelers to developing countries participated in a follow-up study of the health risks associated with short (less than three months) visits to these nations. Travelers to the Greek or Canary Islands served as a control cohort. Participants completed a questionnaire to elicit information regarding pretravel vaccinations, malaria prophylaxis, and health problems during and after their journey. Relevant infections were confirmed by the respondent's personal physician. The questionnaire was completed by 10,524 travelers; the answer rate was 73.8%. After a visit to developing countries, 15% of the travelers reported health problems, 8% consulted a doctor, and 3% were unable to work for an average of 15 days. The incidence of infection per month abroad was as follows: giardiasis, 7/1,000; amebiasis, 4/1,000; hepatitis, 4/1,000; gonorrhea, 3/1,000; and malaria, helminthiases, or syphilis, <1/1,000. There were no cases of typhoid fever or choler

    Monitoring of Carboxypeptidase Digestion by Matrix-Assisted Laser Desorption and Ionization Mass Spectrometry

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    The potential of matrix-assisted laser desorption and ionization mass spectrometry (LDI-MS) is demonstrated by monitoring and analyzing the digestion of (human) pTH (1–34), a synthetic peptide with carboxypeptidases Y and B. All occurring ion signals in the mass spectra could be identified as degraded peptides. By calculating the mass differences between successive degraded peptides, it was possible to identify the released amino acids and to determine 8 amino acids of the C-terminus of the original peptide. For a single MS measurement, only 2 pmol of substrate was needed. Time-course analysis of the cleavage of the first amino acid residue gave insight into the kinetics involved. These measurements strongly support the hope that quantitative information about concentrations can be extracted from LDI-MS

    The global energy balance from a surface perspective

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    In the framework of the global energy balance, the radiative energy exchanges between Sun, Earth and space are now accurately quantified from new satellite missions. Much less is known about the magnitude of the energy flows within the climate system and at the Earth surface, which cannot be directly measured by satellites. In addition to satellite observations, here we make extensive use of the growing number of surface observations to constrain the global energy balance not only from space, but also from the surface. We combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report to infer best estimates for the global mean surface radiative components. Our analyses favor global mean downward surface solar and thermal radiation values near 185 and 342Wm−2, respectively, which are most compatible with surface observations. Combined with an estimated surface absorbed solar radiation and thermal emission of 161 and 397Wm−2, respectively, this leaves 106 Wm−2 of surface net radiation available globally for distribution amongst the non-radiative surface energy balance components. The climate models overestimate the downward solar and underestimate the downward thermal radiation, thereby simulating nevertheless an adequate global mean surface net radiation by error compensation. This also suggests that, globally, the simulated surface sensible and latent heat fluxes, around 20 and 85Wm−2 on average, state realistic values. The findings of this study are compiled into a new global energy balance diagram, which may be able to reconcile currently disputed inconsistencies between energy and water cycle estimate

    The Global Energy Balance Archive (GEBA) version 2017: a database for worldwide measured surface energy fluxes

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    The Global Energy Balance Archive (GEBA) is a database for the central storage of the worldwide measured energy fluxes at the Earth's surface, maintained at ETH Zurich (Switzerland). This paper documents the status of the GEBA version 2017 dataset, presents the new web interface and user access, and reviews the scientific impact that GEBA data had in various applications. GEBA has continuously been expanded and updated and contains in its 2017 version around 500 000 monthly mean entries of various surface energy balance components measured at 2500 locations. The database contains observations from 15 surface energy flux components, with the most widely measured quantity available in GEBA being the shortwave radiation incident at the Earth's surface (global radiation). Many of the historic records extend over several decades. GEBA contains monthly data from a variety of sources, namely from the World Radiation Data Centre (WRDC) in St. Petersburg, from national weather services, from different research networks (BSRN, ARM, SURFRAD), from peer-reviewed publications, project and data reports, and from personal communications. Quality checks are applied to test for gross errors in the dataset. GEBA has played a key role in various research applications, such as in the quantification of the global energy balance, in the discussion of the anomalous atmospheric shortwave absorption, and in the detection of multi-decadal variations in global radiation, known as "global dimming" and "brightening". GEBA is further extensively used for the evaluation of climate models and satellite-derived surface flux products. On a more applied level, GEBA provides the basis for engineering applications in the context of solar power generation, water management, agricultural production and tourism. GEBA is publicly accessible through the internet via http://www.geba.ethz.ch. Supplementary data are available at https://doi.org/10.1594/PANGAEA.873078.ISSN:1866-3516ISSN:1866-350

    Modelling European winter wind storm losses in current and future climate

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    Severe wind storms are one of the major natural hazards in the extratropics and inflict substantial economic damages and even casualties. Insured storm-related losses depend on (i) the frequency, nature and dynamics of storms, (ii) the vulnerability of the values at risk, (iii) the geographical distribution of these values, and (iv) the particular conditions of the risk transfer. It is thus of great importance to assess the impact of climate change on future storm losses. To this end, the current study employs—to our knowledge for the first time—a coupled approach, using output from high-resolution regional climate model scenarios for the European sector to drive an operational insurance loss model. An ensemble of coupled climate-damage scenarios is used to provide an estimate of the inherent uncertainties. Output of two state-of-the-art global climate models (HadAM3, ECHAM5) is used for present (1961-1990) and future climates (2071-2100, SRES A2 scenario). These serve as boundary data for two nested regional climate models with a sophisticated gust parametrizations (CLM, CHRM). For validation and calibration purposes, an additional simulation is undertaken with the CHRM driven by the ERA40 reanalysis. The operational insurance model (Swiss Re) uses a European-wide damage function, an average vulnerability curve for all risk types, and contains the actual value distribution of a complete European market portfolio. The coupling between climate and damage models is based on daily maxima of 10m gust winds, and the strategy adopted consists of three main steps: (i) development and application of a pragmatic selection criterion to retrieve significant storm events, (ii) generation of a probabilistic event set using a Monte-Carlo approach in the hazard module of the insurance model, and (iii) calibration of the simulated annual expected losses with a historic loss data base. The climate models considered agree regarding an increase in the intensity of extreme storms in a band across central Europe (stretching from southern UK and northern France to Denmark, northern Germany into eastern Europe). This effect increases with event strength, and rare storms show the largest climate change sensitivity, but are also beset with the largest uncertainties. Wind gusts decrease over northern Scandinavia and Southern Europe. Highest intra-ensemble variability is simulated for Ireland, the UK, the Mediterranean, and parts of Eastern Europe. The resulting changes on European-wide losses over the 110-year period are positive for all layers and all model runs considered and amount to 44% (annual expected loss), 23% (10years loss),50% (30years loss), and 104% (100years loss). There is a disproportionate increase in losses for rare high-impact events. The changes result from increases in both severity and frequency of wind gusts. Considerable geographical variability of the expected losses exists, with Denmark and Germany experiencing the largest loss increases (116% and 114%, respectively). All countries considered except for Ireland (−22%) experience some loss increases. Some ramifications of these results for the socio-economic sector are discussed, and future avenues for research are highlighted. The technique introduced in this study and its application to realistic market portfolios offer exciting prospects for future research on the impact of climate change that is relevant for policy makers, scientists and economist

    Modulation of Age- and Cancer-Associated DNA Methylation Change in the Healthy Colon by Aspirin and Lifestyle

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    Background Aberrant DNA methylation in gene promoters is associated with aging and cancer, but the circumstances determining methylation change are unknown. We investigated the impact of lifestyle modulators of colorectal cancer (CRC) risk on the stability of gene promoter methylation in the colonic mucosa. Methods We measured genome-wide promoter CpG methylation in normal colon biopsies (n = 1092) from a female screening cohort, investigated the interaction of lifestyle factors with age-dependent increase in methylation with log-linear multivariable regression, and related their modifying effect to hypermethylation in CRC. All statistical tests were two-sided. Results Of 20025 promoter-associated CpGs analyzed, 1713 showed statistically significant age-dependent methylation gains. Fewer CpGs acquired methylation in users of aspirin (≥2 years) and hormonal replacement therapy (HRT age ≥50 years) compared with nonusers (43 vs 1355; 1 vs1377, respectively), whereas more CpGs were affected in smokers (≥20 years) and individuals with a body mass index (BMI) of 25kg/m2 and greater compared with control groups (180 vs 39; 554 vs 144, respectively). Fifty percent of the CpGs showing age-dependent methylation were found hypermethylated in CRC (odds ratio [OR] = 20; 95% confidence interval [CI] = 18 to 23; P < 2×10-16). These loci gained methylation with a higher median rate compared with age-only methylated sites (P = 2×10-76) and were enriched for polycomb regions (OR = 3.67). Importantly, aspirin (P < .001) and HRT use (P < .001) reduced the methylation rate at these cancer-related genes, whereas smoking (P < .001) and high BMI (P = .004) increased it. Conclusions Lifestyle, including aspirin use, modulates age-associated DNA methylation change in the colonic epithelium and thereby impacts the evolution of cancer methylome
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