142 research outputs found
Qualitative and Quantitative X-Ray Diffraction Analysis for Forensic Examination of Duct Tapes
Duct tapes are an increasingly important class of forensic evidence. This research has studied the value of using x-ray diffraction (XRD) to extend the ability of evidence examiners to gain additional information about a duct tape specimen.
Duct tapes are composed of five different layers. Starting from the non-adhesive side, these layers are the release coating, backing, scrim, primer and adhesive. The release coating assists in reducing unwind tension and preventing the tape from sticking to itself when on a roll. The backing layer serves as a support for the adhesive, and is usually based on polyethylene. The scrim is a layer of fibers either embedded in the backing layer or between the backing and adhesive layers. Primers help attach the adhesive to the backing. Pressure sensitive adhesives are based on polymers such as natural or synthetic rubbers combined with tackifying resins and hydrogenated resins. Pigments and additives are added to the backing and adhesive layers in order to achieve the desired tape characteristics and appearance.
A variety of instrumental methods are used to obtain information for discrimination of pressure sensitive tapes including duct tapes. Research has been reported on the evidential value of a range of physical investigations such as, physical and optical examination of thickness, weight/area, fluorescence, and birefringence, as well as instrumental chemical techniques including UV/VIS, FTIR, XRF, NAA, ICP MS, XRD, pyrolysis-GC/MS and isotope-ratio MS. XRD analyses have been used to identify minerals in duct tape but to date, only limited qualitative XRD information has been used and no systematic investigation of the further uses of XRD analysis and databases has been published.
XRD analysis has the potential to offer a convenient, cost effective and non-destructive method for further characterization of the molecular or atomic make up of the tape layers. The diffractogram contains information about the qualitative and quantitative mineral composition and the crystallinity of mineral species and polymers present.
This research has shown that the use of quantitative XRD analysis of duct tapes can differentiate between some duct tape samples from rolls that cannot be distinguished by current, routine analysis methods
Association of Rift Valley fever virus infection with miscarriage in Sudanese women: a cross-sectional study
Background Rift Valley fever virus is an emerging mosquito-borne virus that causes infections in animals and human
beings in Africa and the Arabian Peninsula. Outbreaks of Rift Valley fever lead to mass abortions in livestock, but
such abortions have not been identifi ed in human beings. Our aim was to investigate the cause of miscarriages in
febrile pregnant women in an area endemic for Rift Valley fever.
Methods Pregnant women with fever of unknown origin who attended the governmental hospital of Port Sudan,
Sudan, between June 30, 2011, and Nov 17, 2012, were sampled at admission and included in this cross-sectional
study. Medical records were retrieved and haematological tests were done on patient samples. Presence of viral RNA
as well as antibodies against a variety of viruses were analysed. Any association of viral infections, symptoms, and
laboratory parameters to pregnancy outcome was investigated using Pearsonâs ÏÂČ test.
Findings Of 130 pregnant women with febrile disease, 28 were infected with Rift Valley fever virus and 31 with
chikungunya virus, with typical clinical and laboratory fi ndings for the infection in question. 15 (54%) of 28 women
with an acute Rift Valley fever virus infection had miscarriages compared with 12 (12%) of 102 women negative for
Rift Valley fever virus (p<0·0001). In a multiple logistic regression analysis, adjusting for age, haemorrhagic disease,
and chikungunya virus infection, an acute Rift Valley fever virus infection was an independent predictor of having a
miscarriage (odds ratio 7·4, 95% CI 2·7â20·1; p<0·0001).
Interpretation This study is the fi rst to show an association between infection with Rift Valley fever virus and
miscarriage in pregnant women. Further studies are warranted to investigate the possible mechanisms. Our fi ndings
have implications for implementation of preventive measures, and evidence-based information to the public in
endemic countries should be strongly recommended during Rift Valley fever outbreaks
Optimization of plasma amplifiers
Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long pulses by transferring energy to a shorter pulse via the Raman or Brillouin instabilities. We present an extensive kinetic numerical study of the three-dimensional parameter space for the Raman case. Further particle-in-cell simulations find the optimal seed pulse parameters for experimentally relevant constraints. The high-efficiency self-similar behavior is observed only for seeds shorter than the linear Raman growth time. A test case similar to an upcoming experiment at the Laboratory for Laser Energetics is found to maintain good transverse coherence and high-energy efficiency. Effective compression of a 10 kJ , nanosecond-long driver pulse is also demonstrated in a 15-cm-long amplifier
Early rheumatoid arthritis is characterized by a distinct and transient synovial fluid cytokine profile of T cell and stromal cell origin
Pathological processes involved in the initiation of rheumatoid synovitis remain unclear. We undertook the present study to identify immune and stromal processes that are present soon after the clinical onset of rheumatoid arthritis ( RA) by assessing a panel of T cell, macrophage, and stromal cell related cytokines and chemokines in the synovial fluid of patients with early synovitis. Synovial fluid was aspirated from inflamed joints of patients with inflammatory arthritis of duration 3 months or less, whose outcomes were subsequently determined by follow up. For comparison, synovial fluid was aspirated from patients with acute crystal arthritis, established RA and osteoarthritis. Rheumatoid factor activity was blocked in the synovial fluid samples, and a panel of 23 cytokines and chemokines measured using a multiplex based system. Patients with early inflammatory arthritis who subsequently developed RA had a distinct but transient synovial fluid cytokine profile. The levels of a range of T cell, macrophage and stromal cell related cytokines ( e. g. IL-2, IL-4, IL-13, IL-17, IL-15, basic fibroblast growth factor and epidermal growth factor) were significantly elevated in these patients within 3 months after symptom onset, as compared with early arthritis patients who did not develop RA. In addition, this profile was no longer present in established RA. In contrast, patients with non-rheumatoid persistent synovitis exhibited elevated levels of interferon-gamma at initiation. Early synovitis destined to develop into RA is thus characterized by a distinct and transient synovial fluid cytokine profile. The cytokines present in the early rheumatoid lesion suggest that this response is likely to influence the microenvironment required for persistent RA
Implementation and effects of user participation in playground management: a comparative study of two Swedish municipalities
This paper describes and analyses how customer orientation strategies, with the focus on user
participation, are implemented in playground management and their effects on managersâ attitudes and work with physical playgrounds. A comparative case study was conducted in two Swedish municipalities that involve users in different ways: through a manager-driven
participation process and through informal user-initiated dialogue. The empirical material consisted of qualitative interviews with professionals in the management organisations and studies of local playgrounds. Implementation of strategies for user participation and tactical management activities appeared to be of importance. The manager-driven participation strategy was associated with a particularly positive attitude among managers, but also difficulties such as maintaining continuous dialogue with users. The small differences found in playground provision between the two municipalities give reason to question the physical
effects of participation processes, and show the need for further research
Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat
Nanomaterial of titanium dioxide (TiO2) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO2 particles up to 90 days after intratracheal instillation. TiO2 induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1ÎČ, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied byaninfluxofeosinophilsand neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4+ helper T-cells, but we also demonstrated presence of CD8+T-cells, B-cells, and CD25+T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-Îł] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO2 nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations
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