Kinetics of helium bubble formation in nuclear materials

The formation and growth of helium bubbles due to self-irradiation in plutonium has been modelled by a discrete kinetic equations for the number densities of bubbles having $k$ atoms. Analysis of these equations shows that the bubble size distribution function can be approximated by a composite of: (i) the solution of partial differential equations describing the continuum limit of the theory but corrected to take into account the effects of discreteness, and (ii) a local expansion about the advancing leading edge of the distribution function in size space. Both approximations contribute to the memory term in a close integrodifferential equation for the monomer concentration of single helium atoms. The present boundary layer theory for discrete equations is compared to the numerical solution of the full kinetic model and to previous approximation of Schaldach and Wolfer involving a truncated system of moment equations.Comment: 24 pages, 6 figures, to appear in Physica

Pooled analyses of eribulin in metastatic breast cancer patients with at least one prior chemotherapy.

Based on data from two multicenter, phase III clinical trials (Studies 301 and 305), eribulin (a microtubule dynamics inhibitor) is indicated in the European Union (EU) for patients with locally advanced or metastatic breast cancer (MBC) after ≥1 prior chemotherapy for advanced disease, including an anthracycline and a taxane in either the adjuvant or metastatic setting. Data from Studies 305 and 301 were pooled to investigate the efficacy of eribulin in various subgroups of patients who matched the EU label, including those with human epidermal growth factor receptor 2 (HER2)-negative and triple-negative disease. In Study 305 (NCT00388726), patients were randomized 2:1 to eribulin mesylate 1.4 mg/m(2) (equivalent to eribulin 1.23 mg/m(2) [expressed as free base]) intravenously on days 1 and 8 every 21 days] or treatment of physician's choice after 2-5 prior chemotherapies (≥2 for advanced disease), including an anthracycline and a taxane (in early/advanced setting). In Study 301 (NCT00337103), patients were randomized 1:1 to eribulin (as above) or capecitabine (1.25 g/m(2) orally twice daily on days 1-14 every 21 days) following ≤3 prior chemotherapies (≤2 for advanced disease), including an anthracycline and a taxane. Efficacy end points were investigated in the intent-to-treat population and subgroups, pooled as discussed above. Overall, 1644 patients were included (eribulin: 946; control: 698); baseline characteristics were well matched. Overall survival was significantly longer with eribulin versus control (P < 0.01), as were progression-free survival and clinical benefit rate (both P < 0.05). Significant survival benefits with eribulin versus control were observed in a wide range of patient subgroups, including HER2-negative or triple-negative disease (all P < 0.05). Our findings underline the survival benefit achieved by eribulin used according to EU label in the overall MBC population and in various subgroups of interest, including patients with HER2-negative and triple-negative disease

Feasibility and Safety of Pressurized Intraperitoneal Aerosol Chemotherapy for Peritoneal Carcinomatosis: A Retrospective Cohort Study.

Background. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been introduced as a novel repeatable treatment for peritoneal carcinomatosis. The available evidence from the pioneer center suggests good tolerance and high response rates, but independent confirmation is needed. A single-center cohort was analyzed one year after implementation for feasibility and safety. Methods. PIPAC was started in January 2015, and every patient was entered into a prospective database. This retrospective analysis included all consecutive patients operated until April 2016 with emphasis on surgical feasibility and early postoperative outcomes. Results. Forty-two patients (M : F = 8 : 34, median age 66 (59-73) years) with 91 PIPAC procedures in total (4×: 1, 3×: 17, 2×: 12, and 1×: 12) were analyzed. Abdominal accessibility rate was 95% (42/44); laparoscopic access was not feasible in 2 patients with previous HIPEC. Median initial peritoneal carcinomatosis index (PCI) was 10 (IQR 5-17). Median operation time was 94 min (89-108) with no learning curve observed. One PIPAC application was postponed due to intraoperative intestinal lesion. Overall morbidity was 9% with 7 minor complications (Clavien I-II) and one PIPAC-unrelated postoperative mortality. Median postoperative hospital stay was 3 days (2-3). Conclusion. Repetitive PIPAC is feasible in most patients with refractory carcinomatosis of various origins. Intraoperative complications and postoperative morbidity rates were low. This encourages prospective studies assessing oncological efficacy

Quantifying structural damage from self-irradiation in a plutonium superconductor

The 18.5 K superconductor PuCoGa5 has many unusual properties, including those due to damage induced by self-irradiation. The superconducting transition temperature decreases sharply with time, suggesting a radiation-induced Frenkel defect concentration much larger than predicted by current radiation damage theories. Extended x-ray absorption fine-structure measurements demonstrate that while the local crystal structure in fresh material is well ordered, aged material is disordered much more strongly than expected from simple defects, consistent with strong disorder throughout the damage cascade region. These data highlight the potential impact of local lattice distortions relative to defects on the properties of irradiated materials and underscore the need for more atomic-resolution structural comparisons between radiation damage experiments and theory.Comment: 7 pages, 5 figures, to be published in PR

Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized δ\delta-Pu

The effects on the local structure due to self-irradiation damage of Ga stabilized $\delta$-Pu stored at cryogenic temperatures have been examined using extended x-ray absorption fine structure (EXAFS) experiments. Extensive damage, seen as a loss of local order, was evident after 72 days of storage below 15 K. The effect was observed from both the Pu and Ga sites, although less pronounced around Ga. Isochronal annealing was performed on this sample to study the annealing processes that occur between cryogenic and room temperature storage conditions, where damage is mostly reversed. Damage fractions at various points along the annealing curve have been determined using an amplitude-ratio method, standard EXAFS fitting, and a spherical crystallite model, and provide information complementary to previous electrical resistivity- and susceptibility-based isochronal annealing studies. The use of a spherical crystallite model accounts for the changes in EXAFS spectra using just two parameters, namely, the crystalline fraction and the particle radius. Together, these results are discussed in terms of changes to the local structure around Ga and Pu throughout the annealing process and highlight the unusual role of Ga in the behavior of the lowest temperature anneals.Comment: 13 pages, 10 figure

Deletion of the Coffin-Lowry Syndrome Gene Rsk2 in Mice is Associated With Impaired Spatial Learning and Reduced Control of Exploratory Behavior

Coffin-Lowry Syndrome (CLS) is an X-linked syndromic form of mental retardation associated with skeletal abnormalities. It is caused by mutations of the Rsk2 gene, which encodes a growth factor regulated kinase. Gene deletion studies in mice have shown an essential role for the Rsk2 gene in osteoblast differentiation and function, establishing a causal link between Rsk2 deficiency and skeletal abnormalities of CLS. Although analyses in mice have revealed prominent expression of Rsk2 in brain structures that are essential for learning and memory, evidence at the behavioral level for an involvement of Rsk2 in cognitive function is still lacking. Here, we have examined Rsk2-deficient mice in two extensive batteries of behavioral tests, which were conducted independently in two laboratories in Zurich (Switzerland) and Orsay (France). Despite the known reduction of bone mass, all parameters of motor function were normal, confirming the suitability of Rsk2-deficient mice for behavioral testing. Rsk2-deficient mice showed a mild impairment of spatial working memory, delayed acquisition of a spatial reference memory task and long-term spatial memory deficits. In contrast, associative and recognition memory, as well as the habituation of exploratory activity were normal. Our studies also revealed mild signs of disinhibition in exploratory activity, as well as a difficulty to adapt to new test environments, which likely contributed to the learning impairments displayed by Rsk2-deficient mice. The observed behavioral changes are in line with observations made in other mouse models of human mental retardation and support a role of Rsk2 in cognitive function

Developing and Teaching anMSWCapstone Course Using Case Methods of Instruction

Using an innovative process, the authors and their colleagues developed a case-oriented MSW capstone course. This article outlines the process of developing the course, choosing instructional methods and materials, and preparing instructors to teach the course. It reviews the process of teaching the course, including preparing to teach individual class sessions, identifying and dealing with several instructional challenges that emerged, and designing means to evaluate the course. The authors provide specific recommendations to faculty who wish to provide a similar course. In particular, they show how course development involves substantial, ongoing collaboration by faculty that yield exceptional benefits

Accuracy of 1,2-o-Dilauryl-rac-glycero-3-glutaric Acid-(6'-methylresorufin) Ester (DGGR)-Lipase to Predict Canine Pancreas-Specific Lipase (cPL) and Diagnostic Accuracy of Both Tests for Canine Acute Pancreatitis.

Different lipase assays have variable reported diagnostic accuracies for acute pancreatitis (AP) in dogs. The aims of this retrospective study were to evaluate optimal cutoffs for 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR)-lipase to predict diagnostic cutoffs of canine pancreas-specific lipase (cPL; IDEXX). DGGR-lipase activity and cPL from the same blood draw in 301 dogs with a variety of diseases were compared using Spearman's rank correlation, Cohen's kappa agreement, and receiver operating characteristic (ROC) curves. Activity of DGGR-lipase (10-15,616 U/L) and cPL concentrations (8.1-≥2000 µg/L) were highly correlated (rs = 0.91). Areas under the ROC curves (AUCs) to predict cPL >200 and ≥400 µg/L with DGGR-lipase were 0.97 and 0.99, with optimal cutoffs of 143 U/L (sensitivity (Se) 91.7%; specificity (Sp) 95.3%) and 205 U/L (Se 97.5%; Sp 96.4%), and Cohen's kappa agreements of 0.87 and 0.92, respectively. AUCs for a clinical diagnosis of AP, assigned to 87/301 dogs, with DGGR-lipase (0.75) and cPL (0.76) did not differ significantly (p = 0.48); optimal cutoffs were 161 U/L for DGGR (Se 67%; Sp 81%) and 235 µg/L for cPL (Se 68%; Sp 84%). To conclude, DGGR-lipase is a highly accurate predictor of cPL with a comparable performance when used to diagnose AP in dogs