Study of the

The ^{22}Mg(α,p)^{25}Al reaction rate has been identified as a major source of uncertainty for understanding the nucleosynthesis flow in Type-I x-ray bursts. We report a direct measurement of the energy- and angle-integrated cross sections of this reaction in a 3.3-6.9 MeV center-of-mass energy range using the MUlti-Sampling Ionization Chamber (MUSIC). The new ^{22}Mg(α,p)^{25}Al reaction rate is a factor of ∼4 higher than the previous direct measurement of this reaction within temperatures relevant for x-ray bursts, resulting in the ^{22}Mg waiting point of x-ray burst nucleosynthesis flow to be significantly bypassed via the (α,p) reaction.

Probing the Single-Particle Character of Rotational States in

A beam containing a substantial component of both the J^{π}=5^{+}, T_{1/2}=162 ns isomeric state of ^{18}F and its 1^{+}, 109.77-min ground state is utilized to study members of the ground-state rotational band in ^{19}F through the neutron transfer reaction (d,p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2^{+} band-terminating state. The agreement between shell-model calculations using an interaction constructed within the sd shell, and our experimental results reinforces the idea of a single-particle-collective duality in the descriptions of the structure of atomic nuclei.

Stellar

The ^{36}Ar(n,γ)^{37}Ar (t_{1/2}=35 d) and ^{38}Ar(n,γ)^{39}Ar (269 yr) reactions were studied for the first time with a quasi-Maxwellian (kT∼47 keV) neutron flux for Maxwellian average cross section (MACS) measurements at stellar energies. Gas samples were irradiated at the high-intensity Soreq applied research accelerator facility-liquid-lithium target neutron source and the ^{37}Ar/^{36}Ar and ^{39}Ar/^{38}Ar ratios in the activated samples were determined by accelerator mass spectrometry at the ATLAS facility (Argonne National Laboratory). The ^{37}Ar activity was also measured by low-level counting at the University of Bern. Experimental MACS of ^{36}Ar and ^{38}Ar, corrected to the standard 30 keV thermal energy, are 1.9(3) and 1.3(2) mb, respectively, differing from the theoretical and evaluated values published to date by up to an order of magnitude. The neutron-capture cross sections of ^{36,38}Ar are relevant to the stellar nucleosynthesis of light neutron-rich nuclides; the two experimental values are shown to affect the calculated mass fraction of nuclides in the region A=36-48 during the weak s process. The new production cross sections have implications also for the use of ^{37}Ar and ^{39}Ar as environmental tracers in the atmosphere and hydrosphere.

Study of the

The existence of ^{26}Al (t_{1/2}=7.17×10^{5} yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0^{+} isomer (^{26}Al^{m}), however, severely complicates the astrophysical calculations. We present for the first time a study of the ^{26}Al^{m}(d,p)^{27}Al reaction using an isomeric ^{26}Al beam. The selectivity of this reaction allowed the study of ℓ=0 transfers to T=1/2, and T=3/2 states in ^{27}Al. Mirror symmetry arguments were then used to constrain the ^{26}Al^{m}(p,γ)^{27}Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric ^{26}Al via radiative proton capture reactions, which is expected to dominate the destruction path of ^{26}Al^{m} in asymptotic giant branch stars, classical novae, and core collapse supernovae.

Timing of low bone mineral density and predictors of bone mineral density trajectory in children on long-term warfarin: a longitudinal study.

UNLABELLED: We studied bone mineral density (BMD) of children exposed to long-term warfarin. BMD Z-scores ≤ -2.0 were estimated to occur in less than one fifth of the patients after 10 years of warfarin exposure, and BMI and growth hormone deficiency predicted BMD changes over time. These predictors can help identify high-risk patients. INTRODUCTION: Children with chronic diseases are at increased risk of developing thrombosis, which may require long-term warfarin therapy. Warfarin could further jeopardize the bone health of a population already at risk for bone fragility. Our objective was to investigate the occurrence and timing of low bone mineral density (BMD) and the predictors that influence BMD trajectory in children receiving warfarin for >1 year. METHODS: We analyzed the results of an institutional protocol that includes dual-energy X-ray absorptiometry, with or without spinal X-rays and laboratory biomarkers, as required. RESULTS: Low BMD (age, sex, race, and height-for-age-Z-score adjusted BMD Z-score ≤ -2.0) was detected in 13 % (9/70) of the patients at some point during their follow-up; these patients were more likely to have complex underlying medical conditions and low body mass index (BMI) percentile. BMD Z-scores remained within normal range in 87 % of children. Survival analysis showed that the estimated 10-year abnormal BMD-free rate for the entire group was 81 % (95 % confidence interval [CI] 69 to 93 %). Trajectory analysis revealed that BMI percentiles at baseline and growth hormone deficiency (GHD) were associated with lower BMD Z-scores at the first assessment, whereas baseline BMI percentile was the only predictor of BMD Z-score over time. CONCLUSIONS: Our findings identified BMI and GHD as risk factors influencing BMD in children exposed to long-term warfarin, creating an opportunity for early detection and intervention in these patients.

Constraining the 6.05 MeV 0+ and 6.13 MeV 3- cascade transitions in the 12C(α,γ)16O reaction using the asymptotic normalization coefficients.

The 12C(α,γ)^16O reaction plays a fundamental role in astrophysics and needs to be known with accuracy better than 10%. Cascade γ transitions through the excited states of 16 O are contributing to the uncertainty. We constrained the contribution of the 0+ (6.05 MeV) and 3- (6.13 MeV) cascade transitions by measuring the asymptotic normalization coefficients for these states using the α-transfer reaction 6 Li(12C,d)^16O at sub-Coulomb energy. The contribution of the 0+ and 3- cascade transitions at 300 keV is found to be 1.96 ± 0.3 and 0.12 ± 0.04 keV b for destructive interference of the direct and resonance capture and 4.36 ± 0.45 and 1.44 ± 0.12 keV b for constructive interference, respectively. The combined contribution of the 0+ and 3- cascade transitions to the 12C(α,γ)16O reaction cross section at 300 keV does not exceed 4%. Significant uncertainties have been dramatically reduced.

Compression stockings to prevent post-thrombotic syndrome in adults, a Bayesian meta-analysis.

BACKGROUND: Prescription of compression stockings to prevent post-thrombotic syndrome (PTS) in adults is controversial. We sought to estimate the efficacy of compression stockings vs. placebo/no intervention (control) in preventing PTS, and to estimate the probability of observing a benefit when prescribing compression stockings to prevent PTS. METHODS: We conducted a systematic review of the literature in MEDLINE, EMBASE, and the Cochrane Central Register of Randomized Trials, searching for randomized controlled trials that compared compression stockings, applied in the acute setting of deep vein thrombosis, vs. control to prevent PTS. We used a Bayesian approach for data analysis. RESULTS: Four studies met our inclusion criteria. When comparing intervention vs. control, the estimated odds ratio (OR) was 0.57 (95% Credible Interval (CrI): 0.21 to 1.20) for PTS vs. no PTS and 0.79 (95% CrI 0.31 to 1.67) for severe vs. no/mild/moderate PTS. The probabilities of observing treatment benefits in the population if prescribing compression stockings ranged between 47% (large benefit, OR < 0.50) and 95% (small benefit, OR < 1.00) for any PTS and between 16% and 82% (from large to small benefit) for severe PTS. The probabilities of observing benefit of compression stockings in a future study ranged 44%-76% and 25%-72% (from large to small benefit) for any PTS and severe PTS, respectively. CONCLUSION: Despite heterogeneity, data show that it is still probable to observe some degree of treatment benefit when prescribing compression stockings and to observe some degree of treatment benefit in a future study.

Assessment of cervical involvement in endometrial carcinoma by hysteroscopy and directed biopsy.

The objective of this study was to assess the diagnostic validity of hysteroscopy and directed biopsy for assessing cervical involvement in endometrial carcinoma. We conducted a study of 240 hysteroscopies and 44 cervical biopsies performed on 240 patients with endometrial carcinoma between 2000 and 2005. Hysteroscopy results suggested cervical involvement in 55 cases, of which only 31 were confirmed (a subtotal hysterectomy was performed in two cases, and the resection margins were examined for tumor invasion). In the 31 patients with confirmed cervical involvement, 19 of the hysteroscopy-directed biopsies were positive, 3 were negative, and 3 provided insufficient material. Six patients did not undergo biopsy. In the 24 patients with hysteroscopy false positive, 10 directed biopsies were positive and 9 were negative. Five patients did not undergo biopsy. Hysteroscopy suggested an absence of cervical involvement in 185 patients. Diagnosis was confirmed in 177 cases, and there were eight false negatives. In our case, office hysteroscopy proved to be a valid means of ruling out cervical involvement in endometrial carcinoma. However, it was not a valid means of detecting tumor involvement, even when combined with directed biopsy.

Development of CAPTSureTM - a new index for the assessment of pediatric postthrombotic syndrome.

Essentials We developed a discriminative and evaluative index for pediatric postthrombotic syndrome (PTS). A Delphi-survey was used for item reduction and multi-criteria decision analysis for item weighting. The new index assesses limb PTS based on the relative severity of each sign and symptom. Higher scores related to higher odds of parental dissatisfaction with their child's condition. SUMMARY: Background Postthrombotic syndrome (PTS) is a complication of deep vein thrombosis defined by the presence of characteristic signs and symptoms. We developed a discriminative and evaluative index for the assessment of upper extremity (UE) and lower extremity (LE) pediatric PTS. Methods The items to be included in the index were voted for by 26 pediatric thrombosis experts invited to participate in a Delphi survey. Subsequent item weighting was based on item importance elicited by the use of multicriteria decision analysis (MCDA); 122 healthcare providers and patients/parents were invited to participate in item weighting. The implications of the overall scores were explored by comparison with PTS diagnosis (independently assessed by two clinical experts) and parental satisfaction/dissatisfaction with their child's current condition. Results Items voted for inclusion by at least 70% of the Delphi survey respondents (81% response rate) were pain, paresthesia, swelling, heaviness, endurance, collateral circulation and arm circumference difference for the UE, and pain, paresthesia, swelling, heaviness, tightness, tired limb, redness/purple or blotchy skin, endurance, ulcers and thigh/calf circumference difference for the LE. Items were then weighted by the use of MCDA (82% response rate). The index had excellent discrimination for patients with/without PTS. For every 10-point increase in index scores (with higher scores being indicative of worse PTS), the odds of parental dissatisfaction increased by 75% and 92% in the UE and LE, respectively. Conclusion We report the development of the CAPTSure™ (index for the Clinical Assessment of Postthrombotic Syndrome in children), which reflects collective judgement of the severity of pediatric PTS. We also provide information on the meaning of the scores.

Pediatric post-thrombotic syndrome in children: Toward the development of a new diagnostic and evaluative measurement tool.

OBJECTIVE: Our goal was to conduct the item generation and piloting phases of a new discriminative and evaluative tool for pediatric post-thrombotic syndrome. METHODS: We followed a formative model for the development of the tool, focusing on the signs/symptoms (items) that define post-thrombotic syndrome. For item generation, pediatric thrombosis experts and subjects diagnosed with extremity post-thrombotic syndrome during childhood nominated items. In the piloting phase, items were cross-sectionally measured in children with limb deep vein thrombosis to examine item performance. RESULT: Twenty-three experts and 16 subjects listed 34 items, which were then measured in 140 subjects with previous diagnosis of limb deep vein thrombosis (70 upper extremity and 70 lower extremity). The items with strongest correlation with post-thrombotic syndrome severity and largest area under the curve were pain (in older children), paresthesia, and swollen limb for the upper extremity group, and pain (in older children), tired limb, heaviness, tightness and paresthesia for the lower extremity group. CONCLUSION: The diagnostic properties of the items and their correlations with post-thrombotic syndrome severity varied according to the assessed venous territory. The information gathered in this study will help experts decide which item should be considered for inclusion in the new tool.

Systematic review on heparin-induced thrombocytopenia in children: a call to action.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) has increasingly been reported in children as an indication for use of new alternative anticoagulant drugs (NAADs). OBJECTIVES: To systematically review the literature regarding: (i) the incidence and prevalence of seroconversion and HIT and (ii) the clinical/laboratory findings and management of HIT in children. DESIGN/METHODS: MEDLINE and EMBASE databases were searched for studies that reported pediatric cases of HIT. Methodological reliability assessment of studies was performed with the Loney scale. RESULTS: The incidence of seroconversion in neonates ranged between 0% and 1.7%. There were no cases of neonatal HIT in the included cohorts. The incidence range of seroconversion in the non-neonatal population was 1.3-52%. The incidence of HIT in non-neonates after cardiopulmonary bypass was 0.33% (95%CI, < 0.01-2.04). Whereas more than half of pediatric cases labeled as HIT (30/52) did not include pivotal features of this syndrome, 80% of them received NAADs. CONCLUSION: The incidence of HIT is likely to have been overestimated in children, leading to potential misuse of NAADs in many cases. Clinical findings and laboratory assessment of pediatric cases are poorly described in the literature at present. Thorough laboratory investigation, proper reporting of cases and adequate design of studies are mandatory to elucidate the clinical/laboratory picture of pediatric HIT.