Quantum Monte Carlo Study of Positron Lifetimes in Solids.

We present an analysis of positron lifetimes in solids with unprecedented depth. Instead of modeling correlation effects with density functionals, we study positron-electron wave functions with long-range correlations included. This gives new insight in understanding positron annihilation in metals, insulators, and semiconductors. By using a new quantum Monte Carlo approach for computation of positron lifetimes, an improved accuracy compared to previous computations is obtained for a representative set of materials when compared with experiment. Thus, we present a method without free parameters as a useful alternative to the already existing methods for modeling positrons in solids.

Failed preoperative vacuum bell therapy does not affect outcomes following minimally invasive repair of pectus excavatum.

PURPOSE: It is unknown if failed preoperative vacuum bell (VB) treatment in patients undergoing minimally invasive repair of pectus excavatum (MIRPE), delays repair and/or affects postoperative outcomes. METHODS: A retrospective data analysis including all consecutive patients treated at one single institution undergoing MIRPE was performed between 2000 and 2016. Patients were stratified into preoperative VB therapy versus no previous VB therapy. RESULTS: In total, 127 patients were included. Twenty-seven (21.3%) patients had preoperative VB treatment for 17 months (median, IQR 8-34). All 27 patients stopped VB treatment due to the lack of treatment effect. Eight (47.1%) of 17 assessed VB patients showed signs of skin irritation or hematoma. VB treatment had no effect on length of hospital stay (p = 0.385), postoperative complications (p = 1.0), bar dislocations (p = 1.0), and duration of bar treatment (p = 0.174). Time spent in intensive care unit was shorter in patients with VB therapy (p = 0.007). Long-term perception of treatment including rating of primary operation (p = 0.113), pain during primary operation (p = 0.838), own perspective of look of chest (p = 0.545), satisfaction with the procedure (p = 0.409), and intention of doing surgery again (p = 1.0) were not different between groups. CONCLUSIONS: Failed preoperative VB therapy had no or minimal effect on short-term outcomes and long-term perceptions following MIRPE.

Electrochemical degradation of PAH compounds in process water: a kinetic study on model solutions and a proof of concept study on runoff water from harbour sediment purification.

The present study has investigated the possibility to apply electrochemical oxidation in the treatment of polycyclic aromatic hydrocarbon (PAHs) pollutants in water. The reaction kinetics of naphthalene, fluoranthene, and pyrene oxidation have been studied in a batch recirculation experimental setup applying a commercial one-compartment cell of tubular design with Ti/Pt(90)-Ir(10) anode. The rate of oxidation has been evaluated upon variations in current density, electrolyte composition and concentration. All three PAHs were degraded by direct anodic oxidation in 0.10 M Na(2)SO(4) electrolyte, and the removal rates were significantly enhanced by a factor of two to six in 0.10 M NaCl due to contribution from the indirect hypochlorite oxidation. Second order reaction kinetics was observed for the degradation of naphthalene in all electrolytes whereas fluoranthene and pyrene followed first order kinetics. Decreased current densities from 200 to 15 mA cm(-2) in the NaCl electrolyte also decreased the removal rates, but significantly enhanced the current efficiencies of the PAH oxidation, based on a defined current efficiency constant, k(q). This observation is believed to be due to the suppression of the water oxidation side reaction at lower applied voltages. A proof of concept study in real polluted water demonstrated the applicability of the electrochemical oxidation technique for larger scale use, where especially the indirect chloride mediated oxidation approach was a promising technique. However, the risk and extent of by-product formation needs to be studied in greater detail.

Images of life on the verge of death: dreams and drawings of people with AIDS.

TOPIC: Dreams of people with AIDS help illuminate unconscious activities that can be used to guide the people to a peaceful death. PURPOSE: To explore dreams of the people with AIDS in an attempt to understand unconscious processes SOURCE: Dreams and drawings of three people with AIDS. CONCLUSIONS: Dreams and drawings can be used to understand the unconscious processes of people with AIDS and to help them toward a peaceful death.

From the wings of night: dream work with people who have acquired immunodeficiency syndrome.

Nurses who work with seriously ill and dying patients are engaged in helping them live fully until they die. Most theories of death and dying deal with conscious activities only. Yet many people find relief form the fear and loneliness of life-threatening illness if given the opportunity to express their totality, meaning their unconscious as well as conscious processes. Working with the mind may not be enough. Attending to the unconscious through dream work can allow inner healing to occur, which can support that person as he or she moves into the unknown. The article describes the AIDS Dreamwork Project, the goals of which are to understand patients better and to help them better understand themselves, to help them live and die more consciously, and to discern patterns in their dreams that may be unique to people with acquired immunodeficiency syndrome. Six themes have been identified in the dreams collected so far: wake-up dreams; reassurance dreams; dreams of opposition, separation, or coming together; transition dreams; transformation dreams; and spiritual or archetypal dreams.

The number of circulating CD34+ blood cells predicts the colony-forming capacity of leukapheresis products in children.

In children, only a few guidelines are available for optimizing peripheral blood progenitor cell (PBPC) harvesting. We analyzed by means of flow cytometry and clonogenic assays 60 harvest products obtained from 20 children by standardized leukapheresis after treatment with chemotherapy and CSF. In addition, 27 fresh blood samples obtained prospectively during the mobilization phase were studied. CFU-GM/kg significantly correlated with MNC/kg, CD34+ cells/kg and CD34+33- cells/kg in apheresis products (P < 0.001). In fresh blood samples, CFU-GM/ml significantly correlated with MNC/ml, CD34+ cells/ml and CD34+33- cells/ml (P < 0.001). The numbers of CD34+ cells/ml, CD34+33- cells/ml and MNC/ml in 19 blood samples taken prior to leukapheresis were compared with CFU-GM/kg harvested and thawed after cryopreservation applying multiple regression analysis with stepwise variable selection. The number of circulating CD34+ cells/ml prior to leukapheresis highly correlated with and was predictive for the number of collected CFU-GM/kg (P < 0.001). In addition, a significant correlation (P < 0.05) between the number of progenitor cells/kg reinfused and the time to myeloid and platelet recovery was found in children undergoing high-dose therapy. Our data indicate that a single leukapheresis will be sufficient to obtain a minimum number of 5 x 10(4) CFU-GM/kg if the pre-harvest number of circulating CD34+ cells is > or = 10(5)/ml. Thus, our results will help to optimize PBPC transplantation in children.

Evaluation of the Fresenius cell separator AS 104 for harvesting peripheral blood stem cells in pediatric patients.

In a single institution trial we carried out 35 peripheral blood stem cell harvesting procedures in 12 children with advanced malignancies to evaluate the procedure's safety and the collection efficiency of the Fresenius blood cell separator AS 104 in a pediatric population. Despite a significant mean decrease of 21% (+/-8%) in systolic blood pressure after starting the procedure, all children tolerated leukapheresis without any adverse reaction. After termination of leukapheresis there was a significant decrease of all determined hematological parameters, as compared with pre-harvest values. The mean mononuclear cell recovery was 64% (+/-26%), and in 25/35 (71%) harvesting procedures the minimum progenitor number required for safe autografting could be obtained by one single leukapheresis. We conclude that the Fresenius AS 104 blood cell separator provides a high cell yield and is a safe device for leukapheresis in pediatric patients.