241 research outputs found
Trichinella nativa in a black bear from Plymouth, New Hampshire
A suspected case of trichinellosis was identified in a single patient by the New Hampshire Public Health Laboratories in Concord, NH. The patient was thought to have become infected by consumption of muscle larvae (ML) in undercooked meat from a black bear killed in Plymouth, NH in October 2003 and stored frozen at 20 8C fro 4 months. In January 2004, a 600 g sample of the meat was thawed at 4 8C, digested in hydrochloric acid and pepsin, and larvae were collected by sedimentation. Intact, coiled, and motile ML were recovered (366 larvae per gram (lpg) of tissue), which were passed into mice and pigs. Multiplex PCR revealed a single 127 bp amplicon, indicative of Trichinella nativa. The Reproductive Capacity Index (RCI) for the T. nativa-Plymouth isolate in mice was 24.3. Worm burdens in the diaphragms of two 3-month-old pigs given 2500 ML were 0.05 and 0.2 lpg by 35 days post-inoculation, while 2.2 and 0.75 lpg were recovered from two 3-month-old pigs given 10,000 ML; no larvae were recovered from four 1-year-old pigs given 2500 ML (n = 2) or 10,000 ML (n = 2). Viable larvae were also recovered from frozen black bear meat harvested at two additional locations, one in southern Ontario, Canada, and one in upstate New York, USA. Multiplex PCR using genomic DNA from these parasite samples demonstrated that both isolates were T. nativa. This is the first report of the freeze-resistant species, T. nativa, within the continental United States
The clinical and phenotypical assessment of seronegative villous atrophy; a prospective UK centre experience evaluating 200 adult cases over a 15-year period (2000-2015).
BACKGROUND: Seronegative villous atrophy (SNVA) is commonly attributed to coeliac disease (CD). However, there are other causes of SNVA. More recently angiotensin-2-receptor-blockers (A2RBs) have been reported as an association but data on SNVA have been limited to centres evaluating complex case referrals and not SNVA in general. OBJECTIVES: To provide clinical outcomes and associations in a large prospective study overseeing all newcomers with SNVA. DESIGN: Over a 15-year period (2000-2015) we evaluated 200 adult patients with SNVA at a UK centre. A diagnosis of either seronegative CD (SNCD) or seronegative non-CD (SN-non-CD) was reached. Baseline comparisons were made between the groups, with 343 seropositive CD subjects serving as controls. RESULTS: Of the 200 SNVA cases, SNCD represented 31% (n=62) and SN-non-CD 69% (n=138). The human leucocyte antigen (HLA)-DQ2 and/or DQ8 genotype was present in 61%, with a 51% positive predictive value for SNCD. The breakdown of identifiable causes in the SN-non-CD group comprised infections (27%, n=54), inflammatory/immune-mediated disorders (17.5%, n=35) and drugs (6.5%, n=13; two cases related to A2RBs). However, no cause was found in 18% (n=36) and of these 72% (n=26/36) spontaneously normalised duodenal histology while consuming a gluten-enriched diet. Following multivariable logistic regression analysis an independent factor associated with SN-non-CD was non-white ethnicity (OR 10.8, 95% CI 2.2 to 52.8); in fact, 66% of non-whites had GI infections. On immunohistochemistry all groups stained positive for CD8-T-cytotoxic intraepithelial lymphocytes. However, additional CD4-T helper intraepithelial lymphocytes were occasionally seen in SN-non-CD mimicking the changes associated with refractory CD. CONCLUSIONS: Most patients with SNVA do not have CD, in particular those who are not white. Furthermore, a subgroup with no obvious aetiology will show spontaneous histological resolution while consuming gluten. These findings suggest caution in empirically prescribing a gluten-free diet without investigation
Elastic Wave Transmission at an Abrupt Junction in a Thin Plate, with Application to Heat Transport and Vibrations in Mesoscopic Systems
The transmission coefficient for vibrational waves crossing an abrupt
junction between two thin elastic plates of different widths is calculated.
These calculations are relevant to ballistic phonon thermal transport at low
temperatures in mesoscopic systems and the Q for vibrations in mesoscopic
oscillators. Complete results are calculated in a simple scalar model of the
elastic waves, and results for long wavelength modes are calculated using the
full elasticity theory calculation. We suggest that thin plate elasticty theory
provide a useful and tractable approximation to the full three dimensional
geometry.Comment: 35 pages, including 12 figure
Calculation of NMR Properties of Solitons in Superfluid 3He-A
Superfluid 3He-A has domain-wall-like structures, which are called solitons.
We calculate numerically the structure of a splay soliton. We study the effect
of solitons on the nuclear-magnetic-resonance spectrum by calculating the
frequency shifts and the amplitudes of the soliton peaks for both longitudinal
and transverse oscillations of magnetization. The effect of dissipation caused
by normal-superfluid conversion and spin diffusion is calculated. The
calculations are in good agreement with experiments, except a problem in the
transverse resonance frequency of the splay soliton or in magnetic-field
dependence of reduced resonance frequencies.Comment: 15 pages, 10 figures, updated to the published versio
Mode-Locking in Driven Disordered Systems as a Boundary-Value Problem
We study mode-locking in disordered media as a boundary-value problem.
Focusing on the simplest class of mode-locking models which consists of a
single driven overdamped degree-of-freedom, we develop an analytical method to
obtain the shape of the Arnol'd tongues in the regime of low ac-driving
amplitude or high ac-driving frequency. The method is exact for a scalloped
pinning potential and easily adapted to other pinning potentials. It is
complementary to the analysis based on the well-known Shapiro's argument that
holds in the perturbative regime of large driving amplitudes or low driving
frequency, where the effect of pinning is weak.Comment: 6 pages, 7 figures, RevTeX, Submitte
Does Duodenal Histology Yield Any Other Diagnoses For Iron Deficiency Anaemia Apart From Coeliac Disease?
Disorder Induced Phases in Higher Spin Antiferromagnetic Heisenberg Chains
Extensive DMRG calculations for spin S=1/2 and S=3/2 disordered
antiferromagnetic Heisenberg chains show a rather distinct behavior in the two
cases. While at sufficiently strong disorder both systems are in a random
singlet phase, we show that weak disorder is an irrelevant perturbation for the
S=3/2 chain, contrary to what expected from a naive application of the Harris
criterion. The observed irrelevance is attributed to the presence of a new
correlation length due to enhanced end-to-end correlations. This phenomenon is
expected to occur for all half-integer S > 1/2 chains. A possible phase diagram
of the chain for generic S is also discussed.Comment: 6 Pages and 6 figures. Final version as publishe
Accuracy of the no-biopsy approach for the diagnosis of coeliac disease in adults: a systematic review and meta-analysis
BACKGROUND & AIMS:
Current international guidelines recommend duodenal biopsies to confirm the diagnosis of coeliac disease in adult patients. However, growing evidence suggests that IgA anti-tissue transglutaminase (tTg) antibody levels ≥10 times the upper limit of normal (ULN) can accurately predict coeliac disease, eliminating the need for biopsy. We performed a systematic review and meta-analysis to evaluate the accuracy of the no-biopsy approach to confirm the diagnosis of coeliac disease in adults.
METHODS:
We systematically searched MEDLINE, EMBASE, Cochrane Library and Web of Science from January 1998 to October 2023 for studies reporting the sensitivity and specificity of IgA-tTG ≥10×ULN against duodenal biopsies (Marsh grade ≥2) in adults with suspected coeliac disease. We used a bivariate random-effects model to calculate the summary estimates of sensitivity, specificity, positive and negative likelihood ratios. The positive and negative likelihood ratios were used to calculate the positive predictive value (PPV) of the no-biopsy approach across different pre-test probabilities of coeliac disease. The methodological quality of the included studies was evaluated using the QUADAS-2 tool. This study was registered with PROSPERO, number CRD42023398812.
RESULTS:
A total of 18 studies comprising 12,103 participants from 15 countries were included. The pooled prevalence of biopsy-proven coeliac disease in the included studies was 62% (95% CI, 40% - 83%). The proportion of patients with IgA-tTG ≥10×ULN was 32% (95% CI, 24% - 40%). The summary sensitivity of IgA-tTG ≥10×ULN was 51% (95% CI, 42% - 60%), and the summary specificity was 100% (95% CI, 98% - 100%). The area under the summary receiver operating characteristic curve was 0.83 (95% CI, 0.77 - 0.89). The PPV of the no-biopsy approach to identify patients with coeliac disease was 65%, 88%, 95%, and 99% if coeliac disease prevalence was 1%, 4%, 10% and 40%, respectively. Between-study heterogeneity was moderate (I2 =30.3%), and additional sensitivity analyses did not significantly alter our findings. Only one study had a low risk of bias across all domains.
CONCLUSION:
The results of this meta-analysis suggest that selected adult patients with IgA-tTG ≥10×ULN and a moderate to high pre-test probability of coeliac disease could be diagnosed without undergoing invasive endoscopy and duodenal biopsy
Fatores que afetam a disponibilidade do fósforo e o manejo da adubação fosfatada em solos sob sistema plantio direto
High-Precision Branching Ratio Measurement for the Superallowed + Emitter 74Rb
A high-precision branching-ratio measurement for the superallowed β
+ decay of 74Rb was performed at the
TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electronpositron
tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted β
particles; the 8π spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting γ rays
that were emitted following Gamow-Teller and nonanalog Fermi β
+ decays of 74Rb; and the Pentagonal Array
of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring
β-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4) × 108
detected 74Rb β decays. A total of 58 γ -ray and electron transitions were placed in the decay scheme, allowing
the superallowed branching ratio to be determined as B0 = 99.545(31)%. Combined with previous half-life and
Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed f t value
of 3082.8(65) s. Comparisons between this superallowed f t value and the world-average-corrected Ft value, as
well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models
of the isospin-symmetry-breaking corrections in this mass region.IS
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