Occupational Therapy in Hand Rehabilitation

Department of Rehabilitation Science

Comparisons of Statistical Multifragmentation and Evaporation Models for Heavy Ion Collisions

The results from ten statistical multifragmentation models have been compared with each other using selected experimental observables. Even though details in any single observable may differ, the general trends among models are similar. Thus these models and similar ones are very good in providing important physics insights especially for general properties of the primary fragments and the multifragmentation process. Mean values and ratios of observables are also less sensitive to individual differences in the models. In addition to multifragmentation models, we have compared results from five commonly used evaporation codes. The fluctuations in isotope yield ratios are found to be a good indicator to evaluate the sequential decay implementation in the code. The systems and the observables studied here can be used as benchmarks for the development of statistical multifragmentation models and evaporation codes.Comment: To appear on Euorpean Physics Journal A as part of the Topical Volume "Dynamics and Thermodynamics with Nuclear Degrees of Freedo

Isospin Effects in Nuclear Multifragmentation

We develop an improved Statistical Multifragmentation Model that provides the capability to calculate calorimetric and isotopic observables with precision. With this new model we examine the influence of nuclear isospin on the fragment elemental and isotopic distributions. We show that the proposed improvements on the model are essential for studying isospin effects in nuclear multifragmentation. In particular, these calculations show that accurate comparisons to experimental data require that the nuclear masses, free energies and secondary decay must be handled with higher precision than many current models accord.Comment: 46 pages, 16 figure

Energy resolution and energy-light response of CsI(TI) scintillators for charged particle detection

This article describes the crystal selection and quality control utilized to develop and calibrate a high resolution array of CsI(TI) scintillator crystals for the detection of energetic charged particles. Alpha sources are used to test the light output variation due to thallium doping gradients. Selection of crystals with better than 1% non-uniformity in light output is accomplished using this method. Tests with 240 MeV alpha beam reveal that local light output variations within each of the tested CsI(TI) crystals limit the resolution to about 0.5%. Charge and mass dependences in the energy - light output relationship are determined by calibrating with energetic projectile fragmentation beams.Comment: 24 pages, 7 figure

d-alpha Correlation functions and collective motion in Xe+Au collisions at E/A=50 MeV

The interplay of the effects of geometry and collective motion on d-$\alpha$ correlation functions is investigated for central Xe+Au collisions at E/A=50 MeV. The data cannot be explained without collective motion, which could be partly along the beam axis. A semi-quantitative description of the data can be obtained using a Monte-Carlo model, where thermal emission is superimposed on collective motion. Both the emission volume and the competition between the thermal and collective motion influence significantly the shape of the correlation function, motivating new strategies for extending intensity interferometry studies to massive particles.Comment: Accepted for publication on Physics Letters

Effects of purpurin on proton-pumping ATPase and morphological transition in Candida albicans

Opportunistic human fungal pathogen Candida albicans poses a serious threat to human health. The unicellular microbe exists as part of the normal microbiota on the skin and mucosal surfaces of oral cavity, digestive tract, and urogenital system, but can become invasive and cause local and/or disseminated diseases (candidiasis) in immunocompromised patients with high morbidity and mortality rates (40–60%). Clinical usefulness of the current limited arsenal of antifungal agents has been hampered by toxic side effects, poor pharmacokinetics, and emergence of drug-resistant isolates, indicating a dire need of new antifungal agents. In our earlier study, we have first reported the potent in vitro anti-Candidal activity of purpurin (an anthraquinone pigment found in madder root) against six pathogenic Candida species. One striking virulence trait of C. albicans is its ability to grow and switch between budded yeast and filamentous forms (hyphae), and this yeast-tohypha transition is closely linked with external pH. It is thus conceivable that perturbation of pH homeostasis can be attractive in the management of candidiasis through indirect modulation of morphogenesis. To this end, we extended the investigation and demonstrated the inhibitory actions of purpurin on pH homeostasis and hyphal growth in C. albicans SC5314. At sub-MIC levels (￡0.5 lg ml-1), purpurin suppressed glucosemediated proton pumping ATPase activity in a concentration-dependent manner, and partially inhibited yeast-to-hypha transition and biofilms. Physiological disturbance of cellular metabolism could be excluded as C. albicans growth was not affected. Safe concern and high selectivity of purpurin for C. albicans were justified by its non-toxic nature to primary human gingival fibroblasts (2•MIC; viability = 94%) and keratinocytes (1•MIC; viability = 95%). Therefore, purpurin may represent a potential candidate that deserves further investigations in the development of antifungal strategies against candidiasis - for example, combinational use of purpurin with antifungal agents possessing different modes of action may reduce the likelihood of acquired drug resistance

Purpurin-induced changes in the proteome of Candida albicans

Objectives: To identify the changes in protein abundance in Candida albicans after exposure to purpurin. Methods: The optimal inhibitory dose of purpurin for proteomic analysis of C. albicans was determined by measuring fungal growth in YPD broth in the presence of a range of purpurin concentration (1-5 μg/mL) for 16 h. For proteomic analysis, total soluble proteins of purpurin-treated and untreated (DMSO only) fungal cells were extracted by mechanical disruption. In the first dimension IEF analysis, protein extract (200 μg) was focused on IPG strips (pH 3-10). The second dimension SDS-PAGE was performed on a 12% gel. The relative protein abundance was determined after silver staining. Highly reproducible spots showing (\u3e 1.5-fold) up- or down-regulation were selected for identification using a MALDI-TOF mass spectrometer. The peak lists were searched against NCBI database using an in-house MASCOT searching engine. Results: We identified 12 differentially (five up-regulated; seven down-regulated) expressed protein spots in the purpurin-treated C. albicans. These proteins are involved in stress and heat shock responses, TCA cycle, amino acid and aldehyde metabolism, and mitochondrial functions. Of special interest was a substantial increase (\u3e 3 fold) of the cellular level of aryl alcohol dehydrogenase. Conclusions: Purpurin induces changes in the proteome of C. albicans. Comparison of the differential protein expression patterns of the purpurin-treated C. albicans provides a better understanding of the antifungal mechanisms. The inhibitory effect of purpurin on Candida morphogenesis may be attributed to the up-regulation of aryl alcohol dehydrogenase, a crucial enzyme involved in the synthesis of quorum sensing molecules