Mass Equilibration and Fluctuations in the Angular Momentum Dependent Dynamics of Heavy Element Synthesis Reactions.

Mass and angle distributions for the ^{52}Cr+^{198}Pt and ^{54}Cr+^{196}Pt reactions (both forming ^{250}No) were measured and subtracted, giving new information on fast quasifission mass evolution, and the first direct determination of the dependence of sticking times on angular momentum. TDHF calculations showed good agreement with average experimental values, but experimental mass distributions unexpectedly extended to symmetric splits while the peak yield remained close to the initial masses. This implies a strong role of fluctuations in mass division early in the collision, giving insights into the transition from fast energy dissipative deep-inelastic collisions to quasifission.

Origins of Incomplete Fusion Products and the Suppression of Complete Fusion in Reactions of

Above-barrier complete fusion involving nuclides with low binding energy is typically suppressed by 30%. The mechanism that causes this suppression, and produces the associated incomplete fusion products, is controversial. We have developed a new experimental approach to investigate the mechanisms that produce incomplete fusion products, combining singles and coincidence measurements of light fragments and heavy residues in ^{7}Li+^{209}Bi reactions. For polonium isotopes, the dominant incomplete fusion product, only a small fraction can be explained by projectile breakup followed by capture: the dominant mechanism is triton cluster transfer. Suppression of complete fusion is therefore primarily a consequence of clustering in weakly bound nuclei rather than their breakup prior to reaching the fusion barrier. This implies that suppression of complete fusion will occur in reactions of nuclides where strong clustering is present.

Mechanisms Suppressing Superheavy Element Yields in Cold Fusion Reactions.

Superheavy elements are formed in fusion reactions which are hindered by fast nonequilibrium processes. To quantify these, mass-angle distributions and cross sections have been measured, at beam energies from below-barrier to 25% above, for the reactions of ^{48}Ca, ^{50}Ti, and ^{54}Cr with ^{208}Pb. Moving from ^{48}Ca to ^{54}Cr leads to a drastic fall in the symmetric fission yield, which is reflected in the measured mass-angle distribution by the presence of competing fast nonequilibrium deep inelastic and quasifission processes. These are responsible for reduction of the compound nucleus formation probablity P_{CN} (as measured by the symmetric-peaked fission cross section), by a factor of 2.5 for ^{50}Ti and 15 for ^{54}Cr in comparison to ^{48}Ca. The energy dependence of P_{CN} indicates that cold fusion reactions (involving ^{208}Pb) are not driven by a diffusion process.

Exploring Zeptosecond Quantum Equilibration Dynamics: From Deep-Inelastic to Fusion-Fission Outcomes in

Energy dissipative processes play a key role in how quantum many-body systems dynamically evolve toward equilibrium. In closed quantum systems, such processes are attributed to the transfer of energy from collective motion to single-particle degrees of freedom; however, the quantum many-body dynamics of this evolutionary process is poorly understood. To explore energy dissipative phenomena and equilibration dynamics in one such system, an experimental investigation of deep-inelastic and fusion-fission outcomes in the ^{58}Ni+^{60}Ni reaction has been carried out. Experimental outcomes have been compared to theoretical predictions using time dependent Hartree-Fock and time dependent random phase approximation approaches, which, respectively, incorporate one-body energy dissipation and fluctuations. Excellent quantitative agreement has been found between experiment and calculations, indicating that microscopic models incorporating one-body dissipation and fluctuations provide a potential tool for exploring dissipation in low-energy heavy ion collisions.

Evidence for the Role of Proton Shell Closure in Quasifission Reactions from X-Ray Fluorescence of Mass-Identified Fragments.

The atomic numbers and the masses of fragments formed in quasifission reactions are simultaneously measured at scission in ^{48}Ti+^{238}U reactions at a laboratory energy of 286 MeV. The atomic numbers are determined from measured characteristic fluorescence x rays, whereas the masses are obtained from the emission angles and times of flight of the two emerging fragments. For the first time, thanks to this full identification of the quasifission fragments on a broad angular range, the important role of the proton shell closure at Z=82 is evidenced by the associated maximum production yield, a maximum predicted by time-dependent Hartree-Fock calculations. This new experimental approach gives now access to precise studies of the time dependence of the N/Z (neutron over proton ratios of the fragments) evolution in quasifission reactions.

Covert stroke after non-cardiac surgery: a prospective cohort study.

BACKGROUND: Overt stroke after non-cardiac surgery has a substantial impact on the duration and quality of life. Covert stroke in the non-surgical setting is much more common than overt stroke and is associated with an increased risk of cognitive decline and dementia. Little is known about covert stroke after non-cardiac, non-carotid artery surgery. METHODS: We undertook a prospective, international cohort study to determine the incidence of covert stroke after non-cardiac, non-carotid artery surgery. Eligible patients were ≥65 yr of age and were admitted to hospital for at least three nights after non-cardiac, non-carotid artery surgery. Patients underwent a brain magnetic resonance study between postoperative days 3 and 10. The main outcome was the incidence of perioperative covert stroke. RESULTS: We enrolled a total of 100 patients from six centres in four countries. The incidence of perioperative covert stroke was 10.0% (10/100 patients, 95% confidence interval 5.5-17.4%). Five of the six centres that enrolled patients reported an incident covert stroke, and covert stroke was found in patients undergoing major general (3/27), major orthopaedic (3/41), major urological or gynaecological (3/22), and low-risk surgery (1/12). CONCLUSIONS: This international multicentre study suggests that 1 in 10 patients ≥65 yr of age experiences a perioperative covert stroke. A larger study is required to determine the impact of perioperative covert stroke on patient-important outcomes. CLINICAL TRIAL REGISTRATION: NCT01369537.

Interplay between quantum shells and orientation in quasifission.

The quasifission mechanism hinders fusion in heavy systems through breakup within zeptoseconds into two fragments with partial mass equilibration. Its dependence on the structure of both the collision partners and the final fragments is a key question. Our original approach is to combine an experimental measurement of the fragments' mass-angle correlations in (40)Ca+(238)U with microscopic quantum calculations. We demonstrate an unexpected interplay between the orientation of the prolate deformed (238)U with quantum shell effects in the fragments. In particular, calculations show that only collisions with the tip of (238)U produce quasifission fragments in the magic Z=82 region, while collisions with the side are the only ones that may result in fusion.

48Ca+249Bk fusion reaction leading to element Z = 117: long-lived α-decaying 270Db and discovery of 266Lr.

The superheavy element with atomic number Z=117 was produced as an evaporation residue in the (48)Ca+(249)Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-µs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope (294)117 and its decay products. A hitherto unknown α-decay branch in (270)Db (Z = 105) was observed, which populated the new isotope (266)Lr (Z = 103). The identification of the long-lived (T(1/2) = 1.0(-0.4)(+1.9) h) α-emitter (270)Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an "island of stability."

Predominant time scales in fission processes in reactions of S, Ti and Ni with W: zeptosecond versus attosecond.

The inhibition of fusion by quasifission is crucial in limiting the formation of superheavy elements in collisions of heavy nuclei. Time scales of ∼10(-18) s inferred for fissionlike events from recent crystal blocking measurements were interpreted to show either that quasifission itself is slower than previously believed, or that the fraction of slow fusion-fission is higher than expected. New measurements of mass-angle distributions for (48)Ti and (64)Ni bombarding W targets show that in these reactions quasifission is the dominant process, typically occurring before the system formed after contact has made a single rotation, corresponding to time scales of ≤10(-20) s.

First Study on Nihonium (Nh, Element 113) Chemistry at TASCA.

Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p 1/2 sub-shell, which originates from a large spin-orbit splitting between the 7p 1/2 and 7p 3/2 orbitals. One unpaired electron in the outermost 7p 1/2 sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.

Poisoning, stings and bites in children-- what is new? An experience from a tertiary care hospital in Kolkata.

Poisonings, stings and bites continue to be important cause of pediatric morbidity and hospitalization. The toxic product involved in the poisoning varies in different geographical areas and in same area over time. A retrospective study was conducted amongst the children of the age group up to 12 years admitted to a tertiary care hospital in Kolkata from January 2005 to December 2008. Total number of admissions was 17019 and that for accidental poisoning was 451 (2.65%). Kerosene constituted the largest group (54.55%). Mosquito coil and refill liquid were the new additions to the list of poisons and their ingestion was cause for admission of 15 (3.33%) children. The number of admissions due to stings and bites was 108 (0.63% of all admissions) during the above period. Of all the cases, 9 (1.83%) cases of accidental poisoning and 4 (3.7%) cases of stings and bites died.

Profile of pediatric dengue cases from a tertiary care hospital in Kolkata.

A study was conducted on the 52 serologically positive cases of dengue, admitted to the Dept. of Paediatrics, R.G. Kar Medical College & Hospital, from an outbreak in Kolkata. The most unusual feature observed in this study was that the rash in some cases was urticarial and intensely pruritic. The shock appeared early in the course of the disease and it was less commonly associated with bleeding (22%). One out of three dengue cases was a severe disease. It was not possible to predict a severe disease from the early symptomatology.

Characteristics of patients who made gains at a geriatric day hospital.

The charts of patients who attended a geriatric day hospital (DH) over a 16-month period were reviewed retrospectively (n = 112). Home visits were conducted on consenting patients who made gains (either functional, psychosocial or medical) according to the chart review; they (and/or their caregivers) were questioned about what gains were made at the DH and whether these gains were still present. Initial gains (n = 77, or 69%) were gains identified by chart review, and confirmed by patients at the home visit (when a home visit was possible). Patients who had home visits performed (n = 58) were further classified as to if they had persistent gains or not. Measurements of mood, function, cognition, mobility, balance, and medications were also collected. Patients were defined as having had persistent gains if they relayed gains were still present and, when a gain was measurable (e.g., mobility), there had to be objective evidence of persistent improvement. Backwards elimination modeling using logistic regression analyses was conducted to look for characteristics of patients who made initial gains and had persistent gains. In gender-adjusted analyses, people with cardiac conditions (p = 0.006) or depression (p = 0.047) were most likely to make initial gains whereas those with dementia were less likely to make initial gains (p = 0.005). There were no statistically significant associations (p < 0.05) found between any of the variables examined and the likelihood of having persistent gains. This study suggests that certain types of patients may be more likely to benefit, at least initially, from a DH program.

Circulating immune complexes in multiple sclerosis: relation with disease activity.

Two hundred fifty-four MS patients were studied for circulating immune complexes (CIC) by three different assays: Raji-RIA, Clq-PEG, and Conglutinin-BA. Thirty-five percent of the sera were positive by one or more of these tests; Raji-RIA had the highest sensitivity (29.4%). Incidence of CIC in acute relapse, progressive, remission, and stable state of MS was 33.3%, 30.2%, 26.1%, and 23.1%, respectively, by Raji-RIA, compared with 7.75% and 8.82% among normal and neurologic controls. The incidence of CIC in neurologic controls differed significantly from both acute relapse and progressive disease, and almost significantly from patients in remission. There was no significant difference between patients with stable MS and neurologic controls, and there was no association of CIC with HLA-B7.

Three polyethylene glycol dependent methods for the detection or circulating immune complexes in pathological sera: comparison with the Raji cell method.

A composite method using polyethylene glycol (PEG) and different markers for detecting circulating immune complexes (CIC) is described. The markers used are bovine conglutinin (RK-BA), C1q (C1q-BA) and IgG, IgM quantitation of PEG precipitate (RID-Ig). A composite scoring system is used in interpreting results from individual assays. The sensitivity of multiple PEG methods (MPM) was determined in 418 serum samples and compared with Raji cell assay in 204. Correlations between individual assays, viz., RK-BA-C1q-BA, RID-Ig and Raji cell test in several disease conditions including rheumatoid arthritis, glomerulonephritis, post-renal transplantation, maintenance haemodialysis, multiple sclerosis and normal pregnancies were computed. The relative discriminatory ability of a single PEG technique to differentiate normal from pathological sera in these disease states was observed in comparison with the composite PEG index. This index gives an improved assessment of abnormal sera, is simple and sensitive and has some advantages over biological techniques such as the Raji cell assay.U

A multicenter study of noncompliance with continuous ambulatory peritoneal dialysis exchanges in US and Canadian patients.

Recent evidence suggested that noncompliance (NC) with continuous ambulatory peritoneal dialysis (CAPD) exchanges may be more common in US than in Canadian dialysis centers. This issue was investigated using a questionnaire-based method in 656 CAPD patients at 14 centers in the United States and Canada. NC was defined as missing more than one exchange per week or more than two exchanges per month. Patients were ensured of the confidentiality of their individual results. Mean patient age was 56 +/- 16 years, 52% were women, and 39% had diabetes. The overall admitted rate of NC was 13%, with a rate of 18% in the United States and 7% in Canada (P < 0.001). NC was more common in younger patients (P < 0.0001), those without diabetes (P < 0.001), and employed patients (P < 0.05). It was also more common in black and Hispanic than in Asian and white patients (P < 0.001). NC was more common in patients prescribed more than four exchanges daily (P < 0.0001) but was not affected by dwell volume. On multiple regression analysis, the independent predictors of NC, in order of importance, were being prescribed more than four exchanges per day, black race, being employed, younger age, and not having diabetes. Being treated in a US unit did not quite achieve significance as a multivariate independent predictor. These findings suggest that NC is not uncommon in CAPD patients and is more frequent in US than in Canadian patients. However, country of residence is less powerful as a predictor of NC than a variety of other demographic and prescription factors.

Subcutaneous fluid infusion in a long-term care setting.

OBJECTIVE: To study the use of hypodermoclysis in a long-term care setting for chronic fluid supplementation and to compare it to intravenous (IV) fluid in the treatment of acute mild to moderate dehydration. DESIGN: A prospective observational study. PARTICIPANTS: Fifty-five residents of a long-term care facility treated with fluid therapy during a 5-week period. MAIN OUTCOME MEASURES: Efficacy of hydration and adverse effects were obtained from detailed chart review, interviews with healthcare providers, and investigators' observations. RESULTS: The study subjects were frail older people. Hypodermoclysis was used for maintenance fluid needs in 24 residents; none of these residents required any additional fluid therapy for dehydration. In addition, 37 residents received fluids for acute dehydration. In these residents, hypodermoclysis was associated with clinical improvement in 57% and no clinical change in 25%. Recipients of IV fluids improved 81% of the time and the remainder were unchanged. Hypodermoclysis was associated with fewer fluid therapy-related complications relative to IV therapy (P = .04). CONCLUSIONS: Hypodermoclysis is an effective procedure for providing fluids for both chronic maintenance needs and acute situations associated with mild to moderate dehydration in a long-term care setting. Hypodermoclysis appears safer and can avoid transfers to hospital for rehydration.

Circular dichroism study of membrane dynamics focused on effect of monosialogangliosides.

Monosialogangliosides (GM) purified from bovine brain were incorporated into circular dichroism (CD)-active liposomes and the effects of GM on the membrane dynamics were studied by CD spectroscopy. In the presence of 7 mol% of GM, the phase transition temperature (Tc) of the membrane increased by ca. 10 degrees C compared with the membrane without GM and characteristic CD spectra were observed for CD-active liposomes incorporating GM at low temperature. Asialogangliosides had no effect on the CD spectra or Tc. We have also studied the role of GM in reducing leakage of [3H]sucrose from liposomes composed of egg phosphatidylcholine, dipalmitoyl phosphatidic acid, cholesterol and alpha-tocopherol with a molar ratio of 4 : 1 : 5 : 0.1 in the presence of human plasma at 25 degrees C. The half-life of [3H]-sucrose leakage was 173 h for liposomes incorporating 7 mol% of GM. On the other hand, the half-lives for liposomes incorporating 7 mol% of asialogangliosides and liposomes without glycolipids were 45 and 42 h, respectively. These results indicate that sialic acid on the membrane surface contributes to the increase of Tc, to the change of the aggregation state of phospholipids and to the stabilization of liposomes in plasma.

Uric acid lithiasis associated with altered kinetics of hypoxanthine-guanine phosphoribosyltranferase.

1. A patient is described who had uric acid calculi which obstructed both kidneys. Serum uric acid was 34 mg/100 ml upon admission to hospital, and evidence of precipitation of uric acid in joints was obtained. 2. Total activity of hypoxanthine-guanine phosphoribosyltransferase in erythrocytes lysates from this patient was 44% of normal. Kinetic studies revealed that the apparent Michaelis constant of this enzyme for phosphoribosyl pyrophosphate was elevated 15-fold, while these values for hypoxanthine and guanine were in the normal range.

Antibodies to DNA in patients undergoing long-term hemodialysis.

It has been suggested that antibodies to native DNA occur with some frequency in patients treated by hemodialysis. This has been attributed to the use of the technique. We have investigated 48 patients on maintenance dialysis for the presence of antibodies to single stranded DNA (ss-DNA) and native DNA (n-DNA) compared to a control group of 25 nondialyzed patients with renal disease. In neither group of patients were antibodies to ss-DNA detected frequently. Antibodies to n-DNA were present in three of the dialyzed patients and in none of the control group. The frequency of antibodies in dialysis patients was insignificant in comparison to the same control group of non-dialyzed renal patients. There was no correlation between duration of dialysis and development of antibodies. A drug-induced lupus state is possible, but not established for two of the three patients on dialysis.