Core-scanning X-ray Fluorescence (XRF-CS) is a well-established technique for rapid (<30 s/interval) analysis of sediment core geochemistry at sub-mm resolution with substantially less analytical ...cost compared to methods that rely on physical sub-sampling. Due to issues inherent in analyzing wet sediment of heterogeneous particle size and composition with irregular surface topography using XRF, XRF-CS results are generally considered semi-quantitative. The result of early efforts to calibrate XRF-CS data with conventional geochemical results (e.g. WD- or ED-XRF, ICP-AES, ICP-MS) showed weak correlations for less abundant or poorly detectable elements, however, more recent methods have been proposed to improve accuracy. These methods include: 1) converting XRF-CS results to dry mass concentration; 2) normalizing XRF-CS data to conservative elements (Si, Ca), total counts/second, or X-ray scatter (CIR); and 3) calibration of data using multivariate analysis of elemental log-ratios (MLC). These approaches are not yet widely employed, and require additional testing on a variety of sediment compositions. Recently developed equipment enables analysis of discrete sediment samples, providing >30 replicate analyses for up to 180 samples in a single XRF-CS run. These replicate measurements allow for rigorous testing of precision and accuracy of XRF-CS data. To determine the ideal method of data transformation to improve XRF-CS calibration to quantitative geochemical concentration, 100 lake sediment-surface samples collected from Harvey Lake, New Brunswick, Canada, were analyzed using Itrax-XRF-CS, and then with ICP-MS analysis after multi-acid digestion. Normalization using the CIR and correction for water content showed strong correlation coefficients (Kendall's τ) for elements with atomic number > 18 and high concentrations in the sediment. Results for lighter elements and those with lower concentrations did not perform well using these calibration methods. The MLC provided the most accurate reproduction of observed ICP-MS trends and strong correlations (R) between predicted and actual geochemical concentrations. Based on these results, CIR-normalized or wet-corrected calibrations are ideal for studies where absolute geochemical values are of lesser importance, and the MLC method is appropriate for studies with large numbers of sediment samples (n > 100), or those where absolute concentrations of elements are of greater importance.
•100 sediment surface samples were recovered from Harvey Lake, New Brunswick, Canada.•All samples were analyzed with Itrax-XRF-CS; 28 unique samples were analyzed using ICP-MS following 4-acid digestion.•Several methods of data transformation and correction were applied to Itrax-XRF-CS data, then calibration was attempted.•Normalization to X-ray scatter, correction for water, or use of log-ratios improved the accuracy/precision of calibration.
The NuMI neutrino beam Adamson, P.; Andrews, R.; Augustine, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2016, Letnik:
806
Journal Article
Recenzirano
Odprti dostop
This paper describes the hardware and operations of the Neutrinos at the Main Injector (NuMI) beam at Fermilab. It elaborates on the design considerations for the beam as a whole and for individual ...elements. The most important design details of individual components are described. Beam monitoring systems and procedures, including the tuning and alignment of the beam and NuMI long-term performance, are also discussed.
Purpose: This study was performed to test the effectiveness of a formal supervised exercise program against a home-based exercise program for both walking ability and quality of life endpoints.
...Methods: Patients with arterial claudication were randomized to either a 12-week supervised exercise program (SUPEX) with weekly lectures relating to peripheral vascular disease or to a home exercise group (HOMEX) who attended an identical lecture program and received weekly exercise instruction. The study population included 29 men and 26 women, with a mean age of 69.1 ± 8.1 years. Forty-seven patients completed the 12-week program, 46 were available for testing at completion, and 38 for 6-month testing. Claudication pain time (CPT) and maximum walking time (MWT) on a progressive treadmill exercise test were assessed at baseline, program completion, and 6 months. The Medical Outcomes Study Short Form-36 (SF-36) was administered at these intervals to assess effects on quality of life.
Results: Each group improved ( p < 0.001) in both CPT and MWT at the completion of the 12-week program, which was sustained at the 6-month follow-up. Increase in HOMEX CPT from baseline (3.6 ± 2.73 minutes) to 6-month follow-up (6.6 ± 3.17 minutes) was less than for the SUPEX group (3.8 ± 2.74 to 11.2 ± 4.02 minutes, respectively); similar results were obtained for MWT. At both completion and 6 months, there was a significant intergroup difference for CPT and MWT ( p < 0.004) favoring SUPEX. For both groups, measures of health perception based on the SF-36 demonstrated improvement ( p < 0.002) in Physical Function Subscale, Bodily Pain Subscale, and Physical Composite Score. There were no between-group diffences on the subsets of the SF-36 at the three assessment intervals.
Conclusions: Supervised exercise programs provide superior increased walking ability in the noninterventional therapy of arterial claudication, and both supervised and home based exercise therapy result in improved SF-36 functional measures. The lack of intergroup differences in these measures may be a result of the high degree of interaction with healthcare providers in the HOMEX group. Although a supervised program results in optimal walking benefits, a highly structured home-based program provides similar functional improvement and may be a satisfactory alternative for patients with lesser walking requirements.(J Vasc Sug 1997;25:312-9.)
The objective of this study was to examine the effect of dilution rates (Ds, varying from 0·05 to 0·42 h⁻¹) in glucose-limited continuous culture on cell yield, cell composition, fermentation pattern ...and ammonia assimilation enzymes of Selenomonas ruminantium strain D. All glucose-limited continuous culture experiments were conducted under anaerobic conditions. Except for protein, all cell constituents including carbohydrates, RNA and DNA yielded significant cubic responses to Ds with the highest values at Ds of either 0·10 or 0·20 h⁻¹. At Ds higher than 0·2 h⁻¹, fermentation acid pattern shifted primarily from propionate and acetate to lactate production. Succinate also accumulated at the higher Ds (0·30 and 0·42 h⁻¹). Glucose was most efficiently utilized by S. ruminantium D at 0·20 h⁻¹ after which decreases in glucose and ATP yields were observed. Under energy limiting conditions, glutamine synthetase (GS) and glutamate dehydrogenase (GDH) appeared to be the major enzymes involved in nitrogen assimilation suggesting that other potential ammonia incorporating enzymes were of little importance in ammonia assimilation in S. ruminantium D. GS exhibited lower activities than GDH at all Ds, which indicates that the bacterial growth rate is not a primary regulator of their activities. Studied dilution rates influenced cell composition, fermentation pattern and nitrogen assimilation of S. ruminantium strain D grown in glucose-limited continuous culture. Selenomonas ruminantium D is an ecologically and evolutionary important bacterium in ruminants and is present under most rumen dietary conditions. Characterizing the growth physiology and ammonia assimilation enzymes of S. ruminantium D during glucose limitation at Ds, which simulate the liquid turnover rates in rumen, will provide a better understanding of how this micro-organism responds to differing growth conditions.
Summary Background Glutamate excitotoxicity might contribute to the pathophysiology of amyotrophic lateral sclerosis. In animal models, decreased excitatory aminoacid transporter 2 (EAAT2) ...overexpression delays disease onset and prolongs survival, and ceftriaxone increases EAAT2 activity. We aimed to assess the safety and efficacy of ceftriaxone for amyotrophic lateral sclerosis in a combined phase 1, 2, and 3 clinical trial. Methods This three-stage randomised, double-blind, placebo-controlled study was done at 59 clinical sites in the USA and Canada between Sept 4, 2006, and July 30, 2012. Eligible adult patients had amyotrophic lateral sclerosis, a vital capacity of more than 60% of that predicted for age and height, and symptom duration of less than 3 years. In stages 1 (pharmacokinetics) and 2 (safety), participants were randomly allocated (2:1) to ceftriaxone (2 g or 4 g per day) or placebo. In stage 3 (efficacy), participants assigned to ceftriaxone in stage 2 received 4 g ceftriaxone, participants assigned to placebo in stage 2 received placebo, and new participants were randomly assigned (2:1) to 4 g ceftriaxone or placebo. Participants, family members, and site staff were masked to treatment assignment. Randomisation was done by a computerised randomisation sequence with permuted blocks of 3. Participants received 2 g ceftriaxone or placebo twice daily through a central venous catheter administered at home by a trained caregiver. To minimise biliary side-effects, participants assigned to ceftriaxone also received 300 mg ursodeoxycholic acid twice daily and those assigned to placebo received matched placebo capsules. The coprimary efficacy outcomes were survival and functional decline, measured as the slope of Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) scores. Analyses were by intention to treat. This study is registered with ClinicalTrials.gov , number NCT00349622. Findings Stage 3 included 66 participants from stages 1 and 2 and 448 new participants. In total, 340 participants were randomly allocated to ceftriaxone and 173 to placebo. During stages 1 and 2, mean ALSFRS-R declined more slowly in participants who received 4 g ceftriaxone than in those on placebo (difference 0·51 units per month, 95% CI 0·02 to 1·00; p=0·0416), but in stage 3 functional decline between the treatment groups did not differ (0·09, −0·06 to 0·24; p=0·2370). No significant differences in survival between the groups were recorded in stage 3 (HR 0·90, 95% CI 0·71 to 1·15; p=0·4146). Gastrointestinal adverse events and hepatobiliary adverse events were more common in the ceftriaxone group than in the placebo group (gastrointestinal, 245 of 340 72% ceftriaxone vs 97 of 173 56% placebo, p=0·0004; hepatobiliary, 211 62% vs 19 11%, p<0·0001). Significantly more participants who received ceftriaxone had serious hepatobiliary serious adverse events (41 participants 12%) than did those who received placebo (0 participants). Interpretation Despite promising stage 2 data, stage 3 of this trial of ceftriaxone in amyotrophic lateral sclerosis did not show clinical efficacy. The adaptive design allowed for seamless transition from one phase to another, and central venous catheter use in the home setting was shown to be feasible. Funding National Institute of Neurological Disorders and Stroke.
We hypothesized that particular genetic backgrounds enhance rates of colonization, increase severity of enteritis, and allow for extraintestinal spread when inbred IL-10
−/− mice are infected with ...pathogenic
C. jejuni.
Campylobacter jejuni stably colonized C57BL/6 and NOD mice, while congenic strains lacking IL-10 developed typhlocolitis following colonization that mimicked human campylobacteriosis. However, IL-10 deficiency alone was not necessary for the presence of
C. jejuni in extraintestinal sites. C3H/HeJ
tlr4
−/− mice that specifically express the
Cdcs1 allele showed colonization and limited extraintestinal spread without enteritis implicating this interval in the clinical presentation of
C. jejuni infection. Furthermore, when the IL-10 gene is inactivated as in C3Bir
tlr4
−/− IL-10
−/− mice, enteritis and intensive extraintestinal spread were observed, suggesting that clinical presentations of
C. jejuni infection are controlled by a complex interplay of factors. These data demonstrate that lack of IL-10 had a greater effect on
C. jejuni induced colitis than other immune elements such as TLR4 (C3H/HeJ, C3Bir IL-10
−/−), MHC H-2g7, diabetogenic genes, and CTLA-4 (NOD) and that host genetic background is in part responsible for disease phenotype. C3Bir IL-10
−/− mice where
Cdcs1 impairs gut barrier function provide a new murine model of
C. jejuni and can serve as surrogates for immunocompromised patients with extraintestinal spread.
MINOS and NOνA are two long-baseline neutrino experiments situated along Fermilab's recently upgraded high-intensity NuMI neutrino source. MINOS has capped its long and successful run with a joint ...analysis of its complete beam and atmospheric neutrino and antineutrino data sets, providing new constraints on Δm322 and θ23. MINOS has also produced new limits on light sterile neutrinos in the disappearance channel and on non-standard interactions. NOνA is a next-generation experiment whose 14-kton detector uses a highly active, finely segmented design that offers superb event identification capability. NOνA became fully operational last year and will provide new constraints on (or first measurements of) θ23, Δm322, the neutrino mass hierarchy, and the CP-violating phase δ. In this article, we review the most recent MINOS results, the outlook for MINOS+, and the broad physics scope of NOνA.
The sidereal time dependence of MiniBooNE νe and ν¯e appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the νe and ...ν¯e appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the νe appearance data prefer a sidereal time-independent solution, and the ν¯e appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10−20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for νμ→νe and ν¯μ→ν¯e oscillations. The fit values and limits of combinations of SME coefficients are provided.
Molecular electronics has been proposed as a pathway for high-density nanoelectronic devices. This pathway involves the development of a molecular memory device based on reversible switching of a ...molecule between two conducting states in response to a trigger, such as an applied voltage. Here we demonstrate that voltage-triggered switching is indeed a molecular phenomenon by carrying out studies on the same molecule using three different experimental configurations-scanning tunnelling microscopy, crossed-wire junction, and magnetic-bead junction. We also demonstrate that voltage-triggered switching is distinctly different from stochastic switching, essentially a transient (time-dependent) phenomenon that is independent of the applied voltage.
Estimating cause-specific mortality is often of central importance for understanding the dynamics of wildlife populations. Despite such importance, methodology for estimating and analyzing ...cause-specific mortality has received little attention in wildlife ecology during the past 20 years. The issue of analyzing cause-specific, mutually exclusive events in time is not unique to wildlife. In fact, this general problem has received substantial attention in human biomedical applications within the context of biostatistical survival analysis. Here, we consider cause-specific mortality from a modern biostatistical perspective. This requires carefully defining what we mean by cause-specific mortality and then providing an appropriate hazard-based representation as a competing risks problem. This leads to the general solution of cause-specific mortality as the cumulative incidence function (CIF). We describe the appropriate generalization of the fully nonparametric staggered-entry Kaplan–Meier survival estimator to cause-specific mortality via the nonparametric CIF estimator (NPCIFE), which in many situations offers an attractive alternative to the Heisey–Fuller estimator. An advantage of the NPCIFE is that it lends itself readily to risk factors analysis with standard software for Cox proportional hazards model. The competing risks–based approach also clarifies issues regarding another intuitive but erroneous “cause-specific mortality” estimator based on the Kaplan–Meier survival estimator and commonly seen in the life sciences literature.
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