Neutron radiography, tomography, and diffraction of commercial lithium-ion polymer batteries

Imaging an intact, commercial battery as it cycles and wears is proved possible with neutron imaging. The wavelength range of imaging neutrons corresponds nicely with crystallographic dimensions of the electrochemically active species and the metal electrodes are relatively transparent. The time scale of charge/discharge cycling is well matched to dynamic tomography as performed with a golden ratio based projection angle ordering. The hydrogen content does create scatter which tends to blur internal structure. In this report, three neutron experiments will be described: 3D images of charged and discharged batteries were obtained with monochromatic neutrons at the FRM II reactor. 2D images (PSI) of fresh and worn batteries as a function of charge state may show a new wear pattern. In situ neutron diffraction (SNS) of the intact battery provides more information about the concentrations of electrochemical species within the battery as a function of charge state and wear. The combination of 2D imaging, 3D imaging, and diffraction data show how neutron imaging can contribute to battery development and wear monitoring. © 2013 The Authors. © 2013 The Authors

Incidence and Causes of Hospital Readmission in Pediatric Patients after Hematopoietic Cell Transplantation

AbstractAllogeneic (allo) and autologous (auto) hematopoietic cell transplantation (HCT) provide the potential to cure otherwise fatal diseases but they are resource-intense therapies. There is scant literature describing the burden of hospital readmission in the critical 6-month period of immunosuppression after HCT. We report the incidence, causes, and outcomes of readmission in the 6 months after day 0 of HCT and in the 30 days after hospital discharge. This study is an institutional review board–approved retrospective medical record review of children who underwent HCT at a single institution. Between January 1, 2008 and December 31, 2011, 291 children underwent HCT at our institute. Of these, 140 patients were excluded because they were not followed primarily at our institute for the first 6 months after transplantation, 14 patients were excluded because they died during their initial hospitalization, and 1 patient was excluded because the initial hospitalization was longer than 6 months. Of the remaining 136 patients, 63% had at least 1 readmission. Of the patients who underwent allo-HCT, 78% were readmitted, in contrast to 38% of auto-HCT patients (P < .001). For the 206 readmissions, the mean length of hospital stay was 10.7 days (range, 1 to 129). Seventy-two percent of auto-HCT patients were initially readmitted for fever, and 46% ultimately had a source identified. No risk factors for readmission were found in the auto-HCT group. Fifty-two percent of allo-HCT patients were readmitted for fever and 28% of these patients ultimately had an identified source. Gastrointestinal-related problems accounted for 30% of primary readmissions among allo-HCT patients. Patients with an unrelated donor had a trend towards increased rates of 30-day readmission (P = .06) and were more likely to have a second readmission (P = .002). Patients who were cytomegalovirus (CMV) positive before transplantation were more likely to be readmitted (P = .02). The majority of children who undergo HCT are readmitted during the critical 180 days after transplantation. Readmission is much more common among allo-HCT patients, in particular those with unrelated donors and CMV-positive serologies before transplantation. Fever is the most common cause of readmission in these patients, and serious infections are identified in a significant portion of patients. These findings and future research in this area will help improve both patient education and resource utilization

25-Hydroxy Vitamin D Deficiency Following Pediatric Hematopoietic Stem Cell Transplant

Children may be at increased risk for vitamin D deficiency following HSCT because of lack of sun exposure, the recommended use of sunscreen, dietary insufficiency, malabsorption, and the use of certain medications. We prospectively assessed the prevalence of and risk factors for 25-hydroxy (25-OH) vitamin D deficiency in 67 patients transplanted at our institution. 25-OH vitamin D levels were checked during 3 separate 4-week periods in the spring, autumn, and winter. Subjects were <2 years following transplant and/or being treated for chronic graft-versus-host disease (cGVHD). Levels less than 20 ng/mL were considered deficient, and those less than 30 ng/mL were considered insufficient. The mean 25-OH vitamin D level was 22.8 ng/mL (range: 7-46.2). A total of 80.6% (confidence interval [CI] 69.1%-89.3%) of patients had a level less than the lower limit of the institutional normal range. The deficiency rate was 37.3% (CI 25.8%-50%). The mean parathyroid hormone (PTH) level was 77.5 (SD = 80.5). There was no correlation between 25-OH vitamin D and PTH levels. We evaluated potential risk factors for 25-OH vitamin D deficiency including age, season of testing, sun exposure, sunscreen use, use of steroid or calcineurin inhibitor, race, and dairy intake. In multivariate logistic regression, only older age was found to be a risk factor for deficiency (P = .004). Patients with deficient levels were treated with 50,000 IU of ergocalciferol once weekly for 6 weeks. A postrepletion 25-OH level was available for 22 patients. The majority of repleted patients had a normal posttreatment level (63.6%). The postsupplementation level corrected into the insufficient range for 31.8% of patients and 4.6% remained deficient. Vitamin D insufficiency and deficiency are common following HSCT. Further investigation into potential risk factors and the appropriate supplementation for these patients is warranted

Dynamics of cholesteric structures in an electric field

Motivated by Lehmann-like rotation phenomena in cholesteric drops we study the transverse drift of two types of cholesteric fingers, which form rotating spirals in thin layers of cholesteric liquid crystal in an ac or dc electric field. We show that electrohydrodynamic effects induced by Carr-Helfrich charge separation or flexoelectric charge generation can describe the drift of cholesteric fingers. We argue that the observed Lehmann-like phenomena can be understood on the same basis.Comment: 4 pages, 4 figures, submitted to PR

The X-Ray Origin of Herbig AeBe Systems: New Insights

We present a statistical study of the X-Ray emission toward 22 Herbig AeBe stars using the Chandra archive. We probe the origin of the X-Rays toward Herbig stars: are they intrinsic? This question is addressed by correlations between the physical stellar properties and the X-Ray emission. There is a weak correlation between the continuum radio emission at lambda = 3.6cm and Lx, which suggests that the X-Ray emission depends upon the source. On the other hand, no correlation was found with the stellar rotational period, but that only excludes solar-like magnetic activity as the origin of the X-Rays. Most importantly, the X-Ray luminosity of Herbig AeBe stars have a different distribution than T Tauri stars, suggesting X-Ray emission from an unseen late type star companion can be ruled out with an 80% confidence level. This implies that the Herbig AeBe stars must have magnetic activity. In addition, we report the observation of five sources for the first time, three detections.Comment: 26 pages, 8 figures, accepted for publication in Astronomical Journa

The Adsorption of H2O on TiO2 and SnO2(110) Studied by First-Principles Calculations

First-principles calculations based on density functional theory and the pseudopotential method have been used to investigate the energetics of H$_2$O adsorption on the (110) surface of TiO$_2$ and SnO$_2$. Full relaxation of all atomic positions is performed on slab systems with periodic boundary conditions, and the cases of full and half coverage are studied. Both molecular and dissociative (H$_2$O $\rightarrow$ OH$^-$ + H$^+$) adsorption are treated, and allowance is made for relaxation of the adsorbed species to unsymmetrical configurations. It is found that for both TiO$_2$ and SnO$_2$ an unsymmetrical dissociated configuration is the most stable. The symmetrical molecularly adsorbed configuration is unstable with respect to lowering of symmetry, and is separated from the fully dissociated configuration by at most a very small energy barrier. The calculated dissociative adsorption energies for TiO$_2$ and SnO$_2$ are in reasonable agreement with the results of thermal desorption experiments. Calculated total and local electronic densities of states for dissociatively and molecularly adsorbed configurations are presented and their relation with experimental UPS spectra is discussed

Structure and function of the Rad9-binding region of the DNA-damage checkpoint adaptor TopBP1

TopBP1 is a scaffold protein that coordinates activation of the DNA-damage-checkpoint response by coupling binding of the 9-1-1 checkpoint clamp at sites of ssDNA, to activation of the ATR-ATRIP checkpoint kinase complex. We have now determined the crystal structure of the N-terminal region of human TopBP1, revealing an unexpected triple-BRCT domain structure. The arrangement of the BRCT domains differs significantly from previously described tandem BRCT domain structures, and presents two distinct sites for binding phosphopeptides in the second and third BRCT domains. We show that the site in the second but not third BRCT domain in the N-terminus of TopBP1, provides specific interaction with a phosphorylated motif at pSer387 in Rad9, which can be generated by CK2

Plasmacytoid Dendritic Cells Are Proportionally Expanded at Diagnosis of Type 1 Diabetes and Enhance Islet Autoantigen Presentation to T-Cells Through Immune Complex Capture

OBJECTIVE—Immune-mediated destruction of β-cells resulting in type 1 diabetes involves activation of proinflammatory, islet autoreactive T-cells, a process under the control of dendritic cells of the innate immune system. We tested the hypothesis that type 1 diabetes development is associated with disturbance of blood dendritic cell subsets that could enhance islet-specific autoimmunity