3,098 research outputs found

    Investigation of cohesive and interfacial properties of structural adhesive materials by advanced acoustic methods

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    This research study has examined the feasibility of using acoustic methods for evaluation of the adhesive mechanical properties. The first method is based on the measurement of bulk longitudinal sound velocity during the process of the adhesive cure reaction. Glass transition temperature Tg depends on the extent of reaction of adhesive polymerization; acoustic parameters reflect viscoelastic properties of the material. Acoustic characteristics such us sound velocity or attenuation reflect changes in the adhesive mechanical properties and predict cohesive strength of the adhesive joint. Experimental results show the validity of this assumption. Methodology for monitoring the viscoelastic properties of the adhesive was developed. It was shown that sound velocity in epoxy adhesive correlates with the cohesive strength of the adhesive. The second method is scanning acoustic microscopy which quantitatively allows visualization of the intact adhesive/steel interface. Changes in the microstructure on the intact metal-adhesive interface were investigated. Two dimensional Fourier transforms allow us to determine the main sizes of the granular structure which is 200ÎŒm. It was shown that changes in brightness of the images correspond to changes in the reflection coefficient on the adhesive/metal during polymerization reaction. Adhesive adjacent to the interface has Young\u27s modulus slightly higher than the adhesive in the middle of the layer. Conditions optimal for visualization of the major defects of the adhesive structure were determined. The capability of scanning acoustic microscopy to detect and dynamically monitor small changes in both structure of the metal/epoxy interface and bulk adhesive material was demonstrated

    Addressing the needs of traumatic brain injury with clinical proteomics.

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    BackgroundNeurotrauma or injuries to the central nervous system (CNS) are a serious public health problem worldwide. Approximately 75% of all traumatic brain injuries (TBIs) are concussions or other mild TBI (mTBI) forms. Evaluation of concussion injury today is limited to an assessment of behavioral symptoms, often with delay and subject to motivation. Hence, there is an urgent need for an accurate chemical measure in biofluids to serve as a diagnostic tool for invisible brain wounds, to monitor severe patient trajectories, and to predict survival chances. Although a number of neurotrauma marker candidates have been reported, the broad spectrum of TBI limits the significance of small cohort studies. Specificity and sensitivity issues compound the development of a conclusive diagnostic assay, especially for concussion patients. Thus, the neurotrauma field currently has no diagnostic biofluid test in clinical use.ContentWe discuss the challenges of discovering new and validating identified neurotrauma marker candidates using proteomics-based strategies, including targeting, selection strategies and the application of mass spectrometry (MS) technologies and their potential impact to the neurotrauma field.SummaryMany studies use TBI marker candidates based on literature reports, yet progress in genomics and proteomics have started to provide neurotrauma protein profiles. Choosing meaningful marker candidates from such 'long lists' is still pending, as only few can be taken through the process of preclinical verification and large scale translational validation. Quantitative mass spectrometry targeting specific molecules rather than random sampling of the whole proteome, e.g., multiple reaction monitoring (MRM), offers an efficient and effective means to multiplex the measurement of several candidates in patient samples, thereby omitting the need for antibodies prior to clinical assay design. Sample preparation challenges specific to TBI are addressed. A tailored selection strategy combined with a multiplex screening approach is helping to arrive at diagnostically suitable candidates for clinical assay development. A surrogate marker test will be instrumental for critical decisions of TBI patient care and protection of concussion victims from repeated exposures that could result in lasting neurological deficits

    The Occurrence of Insects and Fungi, and Aflatoxin B Contamination of Stored Sorghum in Demak and Wonogiri Regencies, Central Java

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    The objectives of this study were to collect informations on the method of postharvesthandling of sorghum and to investigate the moisture contents, insects infestation, fungalinfection, and aflatoxin B contents of stored sorghum grains collected from various stagesof the delivery chain in Demak and Wonogiri regencies, Central Java. In Demak regencysorghum cultivation was monoculture, variety cultivated was UPC-S1. In Wonogiri regencysorghum cultivation was intercropping with secondary crop and cassava. Sorghum varietiescultivated were Kawali, Numbu, ZH30, Mandau and Hibrida hybrids. There was a differencebetween the method of postharvest handling of sorghum at farmer and collector levels inDemak andWonogiri regencies. In general the method of postharvest handling of sorghum inDemak regency was more appropriate and more advance compared to that in Wonogiriregency. The moisture contents of sorghum at farmer as well as at collector level in Demakregency (13.0%) and Wonogiri regency (12.9%) were still lower that that of normal (safe)moisture content of sorghum. The number of insect species associated with sorghum invarious distribution level in Demak andWonogiri regencies was 10 and 17 species, respectively.The dominant insects species were and . The number offungal species found in sorghum at various distribution level in Demak andWonogiri regencieswas 23 species, respectively. In general, the dominant fungal species were ,and . In Demak regency aflatoxin B contents of sorghum atfarmer and collector levels were 22.50 and 15.45 ppb, respectively, while in Wonogiri regency2.27 and 10.28 ppb, respectively.insects, fungi, aflatoxin B , stored sorghum, Demak and Wonogiri regencies,Central Jav

    Dietary Exposure Assessment for Aflatoxin B From Processed Peanut Products in Municipality of Bogor 1

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    A research on dietary exposure assessment for aflatoxin B (AFB1) fromprocessed peanutproducts in Municipality of Bogor was carried out. The objectives of this study were todetermine the contents of AFB1 in processed peanut products at retail levels, and to obtaininformation whether there is a risk to public health caused by the consumption of processedpeanut products contaminated by AFB1. Survey of processed peanut product consumptionwas carried out by interviewing each respondent using a questionnaire of weekly processedpeanut product consumption. Sampling of processed peanut products was conducted at thelocations where the respondents obtained processed peanut products. The number of roastedpeanuts with skin pods, flour-coated peanuts and or sauces samples was 33,respectively, while the number of and sauces samples was 18 and 12, respectively.The total number of processed peanut product sampleswas 129.AFB1contentwas determinedusingThin LayerChromatographymethod.Estimation of the dietary exposure assessmentwasdetermined using the actual survey data consisting of AFB1 content, consumption data andbody weight. The highest contaminated sample percentage and mean of AFB1 content wasfound in roasted peanuts with skin pods i.e. 42% of 33 samples and 43.2 ÎŒg/kg, respectively,followed by flour-coated peanuts (30% of 33 samples and 34.3 ÎŒg/kg), and or(21%of 33 samples and 17.1 ÎŒg/kg).Mean of estimated dietary exposure for AFB1 found inchildren was 15.2 ng kg bw day and 95 percentile exposure was 38.9 ng kg bw day , while inadults 9.0 ng kg bw day and 95 percentile exposure was 27.0 ng kg bw day . The excesscancer risk of AFB1 exposure in Bogor fromthis study on children and adults was calculated as193 and 115 cancers/year, respectively-1 -1 th -1 -1-1 -1 th -1 -1pecel gado-gadosiomay sataipecel gado-gado1

    Women entrepreneurship in developing countries: A European example

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    This research investigates women small business entrepreneurship in Albania. The purpose is to provide contextual information to potential future (women) entrepreneurs about how to get into business and overcome challenges. The 11 interviewed Albanian women entrepreneurs explain how they survive a difficult patriarchal society. Contemporary developments in Albania are explained and a comparison is made of recent entrepreneurship research. The results of the research show seven themes: (1) strong relationship between previous experiences and the decision to become self-employed, (2) influence of educational and family background on women’s motivation and career development, (3) gender issues relating to start-up and operating of businesses, (4) major impact of gender on financial related issues, (5) differences in creating networks between men and women, (6) perceived negative career influence because of being women, and (7) similarities with the contextual characteristics of successful Dutch entrepreneurs as found in recent research (Gehrels 2012). Overall conclusion: Albania is developing but still has challenging conditions for women small business entrepreneurs. Further research is suggested in other developing countries.Keywords: women entrepreneurship, small businesses, Albania, gender challenge

    Weak interactions of supersymmetric staus at high energies

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    Neutrino telescopes may have the potential to detect the quasi-stable staus predicted by supersymmetric models. Detection depends on stau electromagnetic energy loss and weak interactions. We present results for the weak interaction contribution to the energy loss of high energy staus as they pass through rock. We show that the neutral current weak interaction contribution to the energy loss increases with energy, but it is much smaller than the photonuclear energy loss, however, the charged current contribution may become the dominant process above the energy of ∌109\sim 10^9 GeV, depending on the parameters of the model. As a consequence, the stau range may be reduced above ∌109\sim 10^9 GeV as compared to the range neglecting weak interactions. We contrast this with the tau range which is barely changed with the inclusion of charged current interactions.Comment: 7 pages, 8 figures, version to be publishe
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