The round state interatomic potential between pairs of closed-shell atoms.

Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1973 .P44. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.Sc.)--University of Windsor (Canada), 1973

Search for Neutron Flux Generation in a Plasma Discharge Electrolytic Cell

Following some recent unexpected hints of neutron production in setups like high-voltage atmospheric discharges and plasma discharges in electrolytic cells, we present a measurement of the neutron flux in a configuration similar to the latter. We use two different types of neutron detectors, poly-allyl-diglicol-carbonate (PADC, aka CR-39) tracers and Indium disks. At 95% C.L. we provide an upper limit of 1.5 neutrons cm^-2 s^-1 for the thermal neutron flux at ~5 cm from the center of the cell. Allowing for a higher energy neutron component the largest allowed flux is 64 neutrons cm^-2 s^-1. This upper limit is two orders of magnitude smaller than what previously claimed in an electrolytic cell plasma discharge experiment. Furthermore the behavior of the CR-39 is discussed to point our possible sources of spurious signals.Comment: 4 pages, 3 figure

Short-Term Bisphosphonate Therapy Could Ameliorate Osteonecrosis: A Complication in Childhood Hematologic Malignancies

Osteonecrosis (ON) is a critical complication in the treatment of childhood leukemia and lymphoma. It particularly affects survivors of acute lymphoblastic leukemia and non-Hodgkin lymphoma reflecting the cumulative exposure to glucocorticosteroid therapy. ON is often multiarticular and bilateral, specially affecting weight-bearing joints. A conventional approach suggests a surgical intervention even if pharmacological options have also recently been investigated. We reported two cases of long time steroid-treated patients who underwent Bone Marrow Transplantation (BMT) for hematological disease. Both patients developed femoral head osteonecrosis (ON) that was diagnosed by magnetic resonance imaging (MRI) and the ON was also accompanied with pain and a limp. Despite of the conventional strategies of therapy, we successfully started a short-term treatment with bisphosphonates in order to decrease the pain and the risk of fracture

Quality of Life and psychopathology in adults who underwent Hematopoietic Stem Cell Transplantation (HSCT) in childhood: a qualitative and quantitative analysis.

Background: Patients who undergo pediatric Hematopoietic Stem Cell Transplantation (HSCT) may experience long-term psychological sequelae and poor Quality of Life (QoL) in adulthood. This study aimed to investigate subjective illness experience, QoL, and psychopathology in young adults who have survived pediatric HSCT. Method: The study involved patients treated with HSCT in the Hematology-Oncology Department between 1984 and 2007. Psychopathology and QoL were investigated using the SCL-90-R and SF-36. Socio-demographic and medical information was also collected. Finally, participants were asked to write a brief composition about their experiences of illness and care. Qualitative analysis of the texts was performed using T-LAB, an instrument for text analysis that allows the user to highlight the occurrences and co-occurrences of lemma. Quantitative analyses were performed using non-parametric tests (Spearman correlations, Kruskal-Wallis and Mann-Whitney tests). Results: Twenty-one patients (9 males) participated in the study. No significant distress was found on the SCL-90 Global Severity Index, but it was found on specific scales. On the SF-36, lower scores were reported on scales referring to bodily pain, general health, and physical and social functioning. All the measures were significantly (p < 0.05) associated with specific socio-demographic and medical variables (gender, type of pathology, type of HSCT, time elapsed between communication of the need to transplant and effective transplantation, and days of hospitalization). With regard to the narrative analyses, males focused on expressions related to the body and medical therapies, while females focused on people they met during treatment, family members, and donors. Low general health and treatment with autologous HSCT were associated with memories about chemotherapy, radiotherapy, and the body parts involved, while high general health was associated with expressions focused on gratitude (V-Test \ub1 1.96). Conclusion: Pediatric HSCT survivors are more likely to experience psychological distress and low QoL in adulthood compared with the general population. These aspects, along with survivors' subjective illness experience, show differences according to specific medical and socio-demographic variables. Studies are needed in order to improve the care and long-term follow-up of these families

Equation of motion for dislocations with inertial effects

An approximate equation of motion is proposed for screw and edge dislocations, which accounts for retardation and for relativistic effects in the subsonic range. Good quantitative agreement is found, in accelerated or in decelerated regimes, with numerical results of a more fundamental nature.Comment: 6 pages, 4 figures, LaTe

Trapping and detrapping effects in high-quality chemical-vapor-deposition diamond films: Pulse shape analysis of diamond particle detectors

An analysis of the time evolution of the response of diamond particle detectors is carried out, using as a probe 5.5 MeV α particles impinging on high-quality diamond films grown by microwave chemical vapor deposition (CVD). Both the amplitude and the time evolution of the pulses are shown to change drastically when the detector is preirradiated with β particles (pumping), a slow component developing after pumping, indicating carriers trapping and releasing (detrapping). Pulse shapes obtained for positive and negative detector polarities are compared in both the as-grown and pumped states. The presence of at least two trapping centers for holes is necessary to explain the results, the shallower having an activation energy of about 0.3 eV. The effects of pumping are clarified, and the different role played by electrons and holes is evidenced. We modify a previous model for trapping-detrapping behavior originally applied to Si(Li) detectors to describe the more complex behavior of CVD diamond detectors, and develop a computer simulation based on it. The simulated pulse shapes agree very well with experiment with reasonable values of the physical parameters involved, making this technique helpful for studying and identifying defects which are responsible for limitation of the efficiency of CVD diamond particle detectors. Field-assisted detrapping seems to take place for fields of about 104 V/cm

Systematic study of the normal and pumped state of high efficiency diamond particle detectors grown by chemical vapor deposition

The efficiency and charge collection distance (CCD) of nuclear particle detectors based on high quality diamond films grown by chemical vapor deposition (CVD) have been systematically studied as a function of the methane content in the growth gas mixture and for varying film thickness. The effects of preirradiation with β particles (pumping) have been thoroughly studied. The results fully support a recently proposed model [Marinelli et al., Appl. Phys. Lett. 75, 3216 (1999)] discussing the role of in-grain defects and grain boundaries in determining the charge collection spectra of CVD diamond films both in the normal and in the pumped state. The model allows us to quantitatively explain the dependence of CCD and efficiency on film thickness, giving a microscopic picture of the effects of preirradiation with ionizing radiation in CVD diamond films. The highest average CCD obtained is 145 μm in a 160 μm thick detector (corresponding to about 50% average efficiency), while the maximum value (about 70% efficiency) is close to 370 μm. In addition, CCD is shown to be higher than film thickness and to monotonically increase with thickness, indicating margins for further improvements. © 2001 American Institute of Physics

Experimental determination of electron and hole mean drift distance: Application to chemical vapor deposition diamond

A study was performed on the experimental determination of electron and hole mean drift distance in chemical vapor deposition polycrystalline diamond. Air was used as an absorbing layer in order to change the energy of the impinging α particles. The results showed that the pumping process was much more effective on hole conduction