1,402 research outputs found

    Glass production at Jalame, Israel: Process, composition and relationship to Roman glass in Europe

    Get PDF
    Following an initial micro-XRF assay, 42 samples of glass from the twentieth-century excavations of the fourth-century CE production site at Jalame, Israel, were selected and analysed by EPMA, with subsets for trace elements by LA-ICP-MS (n=29 samples) and for Hf isotopes by MC-ICP-MS (n=6). Comparison of major elements for ten samples originally measured in Brill (1988) was good, although the earlier SiO2 values are slightly high. Analyses of furnace debris and contaminated glass imply that glass furnaces were made of, or lined with a lime-rich material, leading to contamination by CaO, rather than Al2O3. This confirms that higher alumina contents measured for Jalame glass relative to Roman Mn-decolourised glass of first-third century Europe are significant and it is suggested that the source of the earlier Roman glass lies further North on the eastern Mediterranean coast. A wide range of trace elements are shown to have entered the glass with the addition of manganese, so caution should be exercised when interpreting trace element and isotopic data on glass with significant amounts of Mn, although the effects on REE and some of the lithophiles most often used in provenancing appear minor or insignificant in Jalame glass with MnO below 1.3 wt%. For example, the hafnium isotope composition of the Jalame material does not appear to have been significantly affected and falls within the previously determined Levantine range, distinguishable from Egyptian glass. Associated trace elements indicate that two Mn sources were exploited and this raises the possibility of further investigation of Mn sources in early glass production. The wide range of added manganese suggests problems in obtaining a homogeneous batch and it is suggested that (a) a single initially inhomogeneous furnace load melted to a range of colours, which were subsequently colour-sorted as chunks, and/or (b) the recycling of poorly fused manganese-decolourised glass into later manganese-free batches resulted in the observed variation. The cobalt pigment used was the high-nickel late antique type and allows the introduction of this source to be pushed back from the sixth to the fourth century CE. The use of antimony in glassmaking ceased at around the same time, and it is speculated that these changes were related

    The "Goldilocks Effect" in Cystic Fibrosis: identification of a lung phenotype in the cftr knockout and heterozygous mouse

    Get PDF
    BACKGROUND: Cystic Fibrosis is a pleiotropic disease in humans with primary morbidity and mortality associated with a lung disease phenotype. However, knockout in the mouse of cftr, the gene whose mutant alleles are responsible for cystic fibrosis, has previously failed to produce a readily, quantifiable lung phenotype. RESULTS: Using measurements of pulmonary mechanics, a definitive lung phenotype was demonstrated in the cftr-/- mouse. Lungs showed decreased compliance and increased airway resistance in young animals as compared to cftr+/+ littermates. These changes were noted in animals less than 60 days old, prior to any long term inflammatory effects that might occur, and are consistent with structural differences in the cftr-/- lungs. Surprisingly, the cftr+/- animals exhibited a lung phenotype distinct from either the homozygous normal or knockout genotypes. The heterozygous mice showed increased lung compliance and decreased airway resistance when compared to either homozygous phenotype, suggesting a heterozygous advantage that might explain the high frequency of this mutation in certain populations. CONCLUSIONS: In the mouse the gene dosage of cftr results in distinct differences in pulmonary mechanics of the adult. Distinct phenotypes were demonstrated in each genotype, cftr-/-, cftr +/-, and cftr+/+. These results are consistent with a developmental role for CFTR in the lung

    Hybrid Composite Coatings for Durable and Efficient Solar Hydrogen Generation under Diverse Operating Conditions

    Full text link
    Safe and practical solar-driven hydrogen generators must be capable of efficient and stable operation under diurnal cycling with full separation of gaseous H2 and O2 products. In this study, a novel architecture that fulfills all of these requirements is presented. The approach is inherently scalable and provides versatility for operation under diverse electrolyte and lighting conditions. The concept is validated using a 1 cm2 triple-junction photovoltaic cell with its illuminated photocathode protected by a composite coating comprising an organic encapsulant with an embedded catalytic support. The device is compatible with operation under conditions ranging from 1 m H2SO4 to 1 m KOH, enabling flexibility in selection of semiconductor, electrolyte, membrane, and catalyst. Stable operation at a solar-to-hydrogen conversion efficiency of >10% is demonstrated under continuous operation, as well as under diurnal light cycling for at least 4 d, with simulated sunlight. Operational characteristics are validated by extended time outdoor testing. A membrane ensures products are separated, with nonexplosive gas streams generated for both alkaline and acidic systems. Analysis of operational characteristics under different lighting conditions is enabled by comparison of a device model to experimental data

    Linking Hydrogen (δ2H) Isotopes in Feathers and Precipitation: Sources of Variance and Consequences for Assignment to Isoscapes

    Get PDF
    Background: Tracking small migrant organisms worldwide has been hampered by technological and recovery limitations and sampling bias inherent in exogenous markers. Naturally occurring stable isotopes of H (d 2 H) in feathers provide an alternative intrinsic marker of animal origin due to the predictable spatial linkage to underlying hydrologically driven flow of H isotopes into foodwebs. This approach can assess the likelihood that a migrant animal originated from a given location(s) within a continent but requires a robust algorithm linking H isotopes in tissues of interest to an appropriate hydrological isotopic spatio-temporal pattern, such as weighted-annual rainfall. However, a number of factors contribute to or alter expected isotopic patterns in animals. We present results of an extensive investigation into taxonomic and environmental factors influencing feather d 2 H patterns across North America. Principal Findings: Stable isotope data were measured from 544 feathers from 40 species and 140 known locations. For d 2 H, the most parsimonious model explaining 83 % of the isotopic variance was found with amount-weighted growingseason precipitation d 2 H, foraging substrate and migratory strategy. Conclusions/Significance: This extensive H isotopic analysis of known-origin feathers of songbirds in North America and elsewhere reconfirmed the strong coupling between tissue d 2 H and global hydrologic d 2 H patterns, and accounting for variance associated with foraging substrate and migratory strategy, can be used in conservation and research for th

    Correlation functions quantify super-resolution images and estimate apparent clustering due to over-counting

    Get PDF
    We present an analytical method to quantify clustering in super-resolution localization images of static surfaces in two dimensions. The method also describes how over-counting of labeled molecules contributes to apparent self-clustering and how the effective lateral resolution of an image can be determined. This treatment applies to clustering of proteins and lipids in membranes, where there is significant interest in using super-resolution localization techniques to probe membrane heterogeneity. When images are quantified using pair correlation functions, the magnitude of apparent clustering due to over-counting will vary inversely with the surface density of labeled molecules and does not depend on the number of times an average molecule is counted. Over-counting does not yield apparent co-clustering in double label experiments when pair cross-correlation functions are measured. We apply our analytical method to quantify the distribution of the IgE receptor (Fc{\epsilon}RI) on the plasma membranes of chemically fixed RBL-2H3 mast cells from images acquired using stochastic optical reconstruction microscopy (STORM) and scanning electron microscopy (SEM). We find that apparent clustering of labeled IgE bound to Fc{\epsilon}RI detected with both methods arises from over-counting of individual complexes. Thus our results indicate that these receptors are randomly distributed within the resolution and sensitivity limits of these experiments.Comment: 22 pages, 5 figure

    The malaria testing and treatment landscape in mainland Tanzania, 2016

    Get PDF
    Abstract Background Understanding the key characteristics of malaria testing and treatment is essential to the control of a disease that continues to pose a major risk of morbidity and mortality in mainland Tanzania, with evidence of a resurgence of the disease in recent years. The introduction of artemisinin combination therapy (ACT) as the first-line treatment for malaria, alongside policies to promote rational case management following testing, highlights the need for evidence of anti-malarial and testing markets in the country. The results of the most recent mainland Tanzania ACTwatch outlet survey are presented here, including data on the availability, market share and price of anti-malarials and malaria diagnosis in 2016. Methods A nationally-representative malaria outlet survey was conducted between 18th May and 2nd July, 2016. A census of public and private outlets with potential to distribute malaria testing and/or treatment was conducted among a representative sample of administrative units. An audit was completed for all anti-malarials, malaria rapid (RDT) diagnostic tests and microscopy. Results A total of 5867 outlets were included in the nationally representative survey, across both public and private sectors. In the public sector, availability of malaria testing was 92.3% and quality-assured (QA) ACT was 89.1% among all screened outlets. Sulfadoxine–pyrimethamine (SP) was stocked by 51.8% of the public sector and injectable artesunate was found in 71.4% of all screened public health facilities. Among anti-malarial private-sector stockists, availability of testing was 15.7, and 65.1% had QA ACT available. The public sector accounted for 83.4% of the total market share for malaria diagnostics. The private sector accounted for 63.9% of the total anti-malarial market, and anti-malarials were most commonly distributed through accredited drug dispensing outlets (ADDOs) (39.0%), duka la dawa baridi (DLDBs) (13.3%) and pharmacies (6.7%). QA ACT comprised 33.1% of the national market share (12.2% public sector and 20.9% private sector). SP accounted for 53.3% of the total market for anti-malarials across both private and public sectors (31.3 and 22.0% of the total market, respectively). The median price per adult equivalent treatment dose (AETD) of QA ACT in the private sector was 1.40,almost1.5timesmoreexpensivethanthemedianpriceperAETDofSP(1.40, almost 1.5 times more expensive than the median price per AETD of SP (1.05). In the private sector, 79.3% of providers perceived ACT to be the most effective treatment for uncomplicated malaria for adults and 88.4% perceived this for children. Conclusions While public sector preparedness for appropriate malaria testing and case management is showing encouraging signs, QA ACT availability and market share in the private sector continues to be sub-optimal for most outlet types. Furthermore, it is concerning that SP continues to predominate in the anti-malarial market. The reasons for this remain unclear, but are likely to be in part related to price, availability and provider knowledge or preferences. Continued efforts to implement government policy around malaria diagnosis and case management should be encouraged

    Dynamical and chemical evolution of gas-rich dwarf galaxies

    Full text link
    We study the effect of a single, instantaneous starburst on the dynamical and chemical evolution of a gas-rich dwarf galaxy, whose potential well is dominated by a dark matter halo. We follow the dynamical and chemical evolution of the ISM by means of an improved 2-D hydrodynamical code coupled with detailed chemical yields originating from type II SNe, type Ia SNe and single low and intermediate mass stars (IMS). In particular we follow the evolution of the abundances of H, He, C, N, O, Mg, Si and Fe. We find that for a galaxy resembling IZw18, a galactic wind develops as a consequence of the starburst and it carries out of the galaxy mostly the metal-enriched gas. In addition, we find that different metals are lost differentially in the sense that the elements produced by type Ia SNe are more efficiently lost than others. As a consequence of that we predict larger [α\alpha/Fe] ratios for the gas inside the galaxy than for the gas leaving the galaxy. A comparison of our predicted abundances of C, N, O and Si in the case of a burst occurring in a primordial gas shows a very good agreement with the observed abundances in IZw18 as long as the burst has an age of 31\sim 31 Myr and IMS produce some primary nitrogen. However, we cannot exclude that a previous burst of star formation had occurred in IZw18 especially if the preenrichment produced by the older burst was lower than Z=0.01Z=0.01 Z_{\odot}. Finally, at variance with previous studies, we find that most of the metals reside in the cold gas phase already after few Myr. This result is mainly due to the assumed low SNII heating efficiency, and justifies the generally adopted homogeneous and instantaneous mixing of gas in chemical evolution models.Comment: 25 pages, Latex, 18 figures, accepted for publication in MNRA

    Does trocar-guided tension-free vaginal mesh (Prolift™) repair provoke prolapse of the unaffected compartments?

    Get PDF
    Contains fulltext : 88857.pdf (publisher's version ) (Closed access)INTRODUCTION AND HYPOTHESIS: The objective of this study was to assess the effect of the tension-free vaginal mesh (Prolift) procedure on the non-treated and initially unaffected vaginal compartments. METHODS: This prospective observational cohort study involved 150 patients who underwent a Prolift procedure. Pelvic organ prolapse (POP) quantification and evaluation of prolapse symptoms with validated questionnaires was performed pre-operatively and 6 and 12 months postoperatively. Primary outcome was the rate of POP stage > or = II in the non-treated vaginal compartments. RESULTS: Twenty-three percent of all patients developed a de novo POP stage > or = II in the untreated compartment. This occurred in 46% and 25% of patients after an isolated anterior and isolated posterior Prolift, respectively. CONCLUSION: Tension-free vaginal mesh treatment of one vaginal compartment seems to provoke the development of vaginal prolapse in initially unaffected vaginal compartments, particularly after an isolated anterior Prolift procedure.1 maart 201

    Clostridium septicum sepsis and colorectal cancer - a reminder

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Spontaneous clostridium septicum infections are rare and are associated with a high mortality. Association of clostridium infection with colorectal malignancies have been previously reported and most cases are described in tumours of the ascending colon. We report our experience of clostridium septicum infection in the presence of tumour perforation in a series of two patients as a reminder of its association with sepsis in the presence of colorectal malignancy.</p> <p>Case Presentation</p> <p>We isolated clostridium septicum infection in a series of two patients admitted as emergencies. One patient was found to have a perforated caecal tumour intraoperatively whilst the other had a perforated rectal tumour. The clinical outcome and management of each case are reported and underlying reasons for variations in outcome are discussed.</p> <p>Conclusion</p> <p>Although uncomman, the possibility of clostridium septicum sepsis should be borne in mind in patients who present with underlying malignancy and have sepsis. The cumulative effect of sepsis and malignant perforation is associated with a high morbidity and mortality. Awareness and early diagnosis of clostridium septicum may improve the prognosis of what is usually regarded as a fatal infection.</p

    The Peter Pan paradigm

    Get PDF
    Genetic and environmental agents that disrupt organogenesis are numerous and well described. Less well established, however, is the role of delay in the developmental processes that yield functionally immature tissues at birth. Evidence is mounting that organs do not continue to develop postnatally in the context of these organogenesis insults, condemning the patient to utilize under-developed tissues for adult processes. These poorly differentiated organs may appear histologically normal at birth but with age may deteriorate revealing progressive or adult-onset pathology. The genetic and molecular underpinning of the proposed paradigm reveals the need for a comprehensive systems biology approach to evaluate the role of maternal-fetal environment on organogenesis
    corecore