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.

Parenting experiences of fathers of children with autism spectrum disorder with or without intellectual disability.

BACKGROUND: Fathers of children with autism spectrum disorder (ASD) report more challenges than fathers of typically developing children, which also negatively impacts their psychological well-being. Although not studied to the same extent in fathers of children with ASD, the challenges experienced by fathers of typically developing children have been shown to impact parenting behaviours. Many children with ASD also have intellectual disability (ID), which adds additional parenting stress. The purpose of this qualitative study was to examine perceptions of parenting roles and father-child relationship quality in fathers of children with ASD and ASD/ID. METHODS: Twenty-eight fathers of children with ASD (n = 12) and ASD/ID (n = 16) completed a telephone interview. A phenomenological approach was used by two investigators to analyse the interviews. Both investigators coded the interviews and then discussed the final themes. RESULTS: Five major themes emerged. One theme that emerged was pre-birth expectations, and the remaining themes related to the post-diagnosis period: adjustments, experiences, co-parenting and quality of father-child relationship. Both fathers of a child with ASD and ASD/ID reported on all themes. CONCLUSIONS: Overall, fathers of children with ASD and ASD/ID reported similarly on the themes that emerged. Future research with more diverse samples is needed to continue to understand the fatherhood experience. The findings of this study have implications for the development of parent-focused programmes that are tailored to fathers' unique experiences.

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.

Predicting lipstick sensory properties with laboratory tests.

OBJECTIVE: Sensory perceptions and performance are important to the success of a lipstick formulation, but in vivo evaluation can be expensive and time-consuming. The goal of this work was to develop and use laboratory test methods to predict the sensory and performance properties of lipstick. METHODS: Twelve model lipstick formulations were prepared, in which only the emollient varied, resulting in a variety of sensory and performance properties. The lipsticks were tested for sensory perceptions of spreadability, stickiness, opacity and gloss with a nine-person panel. The performance properties were evaluated with a friction test using a CETR UMT-2 tribometer, an application test using an analytical balance, a tack test using a Texture Analyser TA.XT-Plus and a colour development/retention test using photography and image analysis. The results of the laboratory tests were compared with the results of the sensory panel using statistical modelling. RESULTS: The results of the laboratory tests correlated well with the measured sensory properties. The results of the friction test classified the lipsticks into four groups, which were termed oily, creamy, waxy and sticky; these classifications were also evident in the other laboratory test data. Surprisingly, it was found that the friction test could be used alone to predict all the measured sensory properties with statistical models. The correlation between the coefficient of friction and the measured sensory properties is explained by the balance of adhesive and cohesive properties of the lipstick. These properties are influenced by the emollient and affect the application properties and resulting film. CONCLUSION: The emollient has a significant effect on the sensory and performance properties of a lipstick, which can be predicted with the developed laboratory tests. Furthermore, the friction test can be used to sufficiently predict four important lipstick sensory attributes: spreadability, stickiness, opacity and gloss. Using the methods presented here, lipstick formulations may be more rapidly developed and optimized.

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.

Oxygen cost of walking, physical activity, and sedentary behaviours in rheumatoid arthritis.

OBJECTIVES: To evaluate the oxygen cost of gait and measure physical activity profiles, including time spent sedentary, in people with rheumatoid arthritis (RA) and matched controls. METHOD: We recruited 19 people with RA and 19 controls matched for age, sex, and body mass index (BMI). Demographic details and clinical characteristics of the RA population were recorded. Oxygen uptake per metre walked (oxygen cost) was measured in the laboratory using a portable gas analyser. Activity profiles including the number of steps per day, time spent sedentary (sitting or lying down), and intensity of walking were recorded over 5 days using an activity monitor, from which physical activity was classified by intensity categories. Levels of pain, fatigue, anxiety, and depression were recorded. RESULTS: People with RA walked with a slower self-selected gait speed (p < 0.001) than controls but there was no difference in the oxygen cost of walking (p = 0.992) between the groups. People with RA took fewer steps (p < 0.001), had increased sedentary time (p = 0.029) and lower time walking at cadences commensurate with moderate to vigorous physical activity (MVPA) compared to controls (p < 0.001). Pain, fatigue, and depression were higher in the RA group (all p < 0.001). CONCLUSIONS: The oxygen cost of walking in this cohort of people with RA was similar to that of matched controls but there was an increase in time spent sedentary and a reduction in time spent at cadences commensurate with MVPA. Clinical symptoms such as depression, pain, and fatigue may explain the changes in activity/sedentary behaviours in people with RA and require further investigation.

The heating of gas in a galaxy cluster by X-ray cavities and large-scale shock fronts.

Most of the baryons in galaxy clusters reside between the galaxies in a hot, tenuous gas. The densest gas in their centres should cool and accrete onto giant central galaxies at rates of 10-1,000 solar masses per year. No viable repository for this gas, such as clouds or new stars, has been found. New X-ray observations, however, have revealed far less cooling below X-ray temperatures than expected, altering the previously accepted picture of cooling flows. As a result, most of the gas must be heated to and maintained at temperatures above approximately 2 keV (ref. 3). The most promising heating mechanism is powerful radio jets emanating from supermassive black holes in the central galaxies of clusters. Here we report the discovery of giant cavities and shock fronts in a distant (z = 0.22) cluster caused by an interaction between a radio source and the hot gas surrounding it. The energy involved is approximately 6 x 10(61) erg, the most powerful radio outburst known. This is enough energy to quench a cooling flow for several Gyr, and to provide approximately 1/3 keV per particle of heat to the surrounding cluster.

Determining validity of the PALite and ODFS PACE activity logger for measuring step count in healthy adults.

BACKGROUND: Determining adherence with orthoses is important for clinicians prescribing devices. Measuring orthotic use often relies on patient recall which has poor agreement with objective measures. Measuring step count whilst wearing an orthosis could help objectively quantifying adherence. The Odstock Drop Foot Stimulator (ODFS) Pace, used in foot drop, has an integral activity logger which provides data on step count. The PALite, an accelerometer, measures step count and can be fixed to an ankle foot orthoses (AFO). Both have the potential to provide objective measures of adherence; however, their validity for this purpose has not been determined. RESEARCH QUESTION: To determine the validity of the PALite and ODFS Pace activity logger in measuring total step count, by exploring their level of agreement. METHODS: A convenience sample of sixteen healthy volunteers, aged 18-65, were recruited from Glasgow Caledonian University (GCU). Participants walked continuously for 5 min on a treadmill at three walking speeds; normal (1.3ms-1), slow (0.4 ms-1) and fast (1.7-2.0 ms-1), wearing both the PALite and ODFS Pace. All walks were video recorded, viewed by 2 raters, and observed step count was determined by a click counter. Step count from both devices was validated against observed step count using video recording. The level of agreement between the three methods was established. RESULTS: There was no significant difference between the 3 methods of measuring step count at any walking speed (normal, p = 0.913; slow, p = 0.938; fast, p = 0.566). Good levels of agreement for both devices with observed step count at all 3 walking speeds, with mean percentage differences being between -1.2 and 2.1 % (maximum upper and lower levels of agreement = 19.5 and -18.8 %) was detected. SIGNIFICANCE: Clinicians could consider both devices to objectively measure step count with people who are prescribed foot drop orthoses, thus quantifying orthotic use.

Walking and talking: an investigation of cognitive-motor dual tasking in multiple sclerosis.

BACKGROUND: Deficits in motor functioning, including walking, and in cognitive functions, including attention, are known to be prevalent in multiple sclerosis (MS), though little attention has been paid to how impairments in these areas of functioning interact. OBJECTIVES: This study investigated the effects of performing a concurrent cognitive task when walking in people with MS. Level of task demand was manipulated to investigate whether this affected level of dual-task decrement. METHOD: Eighteen participants with MS and 18 healthy controls took part. Participants completed walking and cognitive tasks under single- and dual-task conditions. RESULTS: Compared to healthy controls, MS participants showed greater decrements in performance under dual-task conditions in cognitive task performance, walking speed and swing time variability. In the MS group, the degree of decrement under dual-task conditions was related to levels of fatigue, a measure of general cognitive functioning and self-reported everyday cognitive errors, but not to measures of disease severity or duration. CONCLUSIONS: Difficulty with walking and talking in MS may be a result of a divided attention deficit or of overloading of the working memory system, and further investigation is needed. We suggest that difficulty with walking and talking in MS may lead to practical problems in everyday life, including potentially increasing the risk of falls. Clinical tools to assess cognitive-motor dual-tasking ability are needed.

Specificity of recumbent cycling as a training modality for the functional movements; sit-to-stand and step-up.

BACKGROUND: The principle of specificity in muscle training requires the training mode to reflect the desired outcome. The observed similarity of lower limb movements during recumbent cycling to the functional movements sit-to-stand and step-up presents the possibility of using recumbent cycling in a rehabilitation context. This may reduce the need to practice the actual task which in some, less able, patients may be labour intensive and patient fatiguing. To date no studies have compared recumbent cycling to these functional movements. This study therefore aimed to compare the lower limb kinematics and muscle activity between recumbent cycling and both sit-to-stand and step-up movements. METHODS: Electromyographic and kinematic signals from 12 young (mean age 42.1 years) healthy participants were collected during the performance of three activities: (1) cycling at 60 rpm, (2) sit-to-stand and (3) a single step-up. Only the extension phase of each movement was compared. FINDINGS: Although the results demonstrated differences in joint movement and muscle activation, e.g., greater gastrocnemius activity during recumbent cycling (P<0.00), knee range of motion and average root mean square activity for rectus femoris, biceps femoris and the sum of the average activity for five muscles recorded showed no difference (P>0.05) suggesting that there was sufficient agreement to support the use of recumbent cycling as a specific training modality for the sit-to-stand and step-up movements. This finding may have positive implications for the rehabilitation of a wide range of patients in the early stages of rehabilitation.

The impact of walking speed on the effects of functional electrical stimulation for foot drop in people with multiple sclerosis.

PURPOSE: Functional electrical stimulation (FES) is effective in assisting people with multiple sclerosis (pwMS) with gait. Previous studies have investigated the effects of FES in pwMS with slow self-selected walking speeds (SSWS). This study reports on the effect of the Odstock Dropped Foot Stimulator (ODFS) on the speed and oxygen (O2) cost of gait in pwMS walking at a range of SSWS. METHODS: Twenty pwMS (mean age 50.4 ± 7.3 years) currently using FES walked at their SSWS for 5 min with and without FES. O2 cost of gait was measured using a gas analysis system, and gait speed was calculated. Data were analysed for all participants, and comparisons were made between those with a SSWS < and >0.8 m/s (walking speed required for community ambulation). RESULTS: Significant improvements in the speed and O2 cost of gait were seen using FES in the group with SSWS <0.8 m/s (n = 11, p = 0.005). When participants' SSWS >0.8 m/s, no difference in gait speed was noted, and a significant increase in O2 cost of gait using FES (n = 9, p = 0.004) was noted. CONCLUSION: FES has a different effect on the speed and O2 cost of gait dependent on the SSWS of pwMS. This requires further investigation. Implications for Rehabilitation Functional electrical stimulation (FES) used for foot drop is effective in improving the speed and oxygen cost of walking in pwMS walking at SSWS <0.8 m/s. FES does not seem to have a beneficial effect on the speed and oxygen cost of walking in pwMS walking at SSWS >0.8 m/s. Further research is needed to understand the possible mechanisms involved so that FES for foot drop can be efficiently prescribed.

Relationship between isokinetic muscle strength and exercise capacity in chronic heart failure.

The exercise intolerance and excessive ventilatory response to exercise of chronic heart failure is associated with abnormalities of skeletal muscle function, in particular a reduction in muscle strength. Isometric and isokinetic leg muscle strength were measured in 10 patients with chronic heart failure and 10 age-matched controls. Each subject undertook maximal exercise testing to measure peak oxygen consumption (V(O2)) and the ventilatory response to exercise as measured by the slope of the relation between ventilation and carbon dioxide production (V(E)/V(CO2) slope). Quadriceps strength (mean (S.D.)) was reduced in heart failure as measured by isometric (444.9 (129.6) N vs. 556.0 (136.0); P<0.01) and isokinetic (123.6 (30.2) Nm vs. 146.8 (40.0); P=0.04). Hamstring strength was also reduced as measured by isokinetic testing (53.6 (15.6) Nm vs. 71.1 (28.1); P=0.02). Isokinetic and isometric strengths correlated, but not closely (r=0.52, P<0.001). There were negative correlations between the V(E)/V(CO2) slope, and isokinetic measures: with average torque, r=-0.62, P<0.004; with peak torque, r=-0.64, P=0.002. We have found evidence for reduced muscle function affecting both knee flexors and extensors. This reduction in muscle strength correlates with the ventilatory response to exercise. These observations lend support to the muscle hypothesis of the generation of symptoms in chronic heart failure.

Widespread risks of dental fluorosis in cotton rats (Sigmodon hispidus) residing on petrochemical waste sites.

Fluoride has been identified as a ubiquitous contaminant of soils where petrochemical wastes have been disposed. The purpose of this study was to assess how widespread toxicity risks are to resident vertebrates from chronic exposure to fluoride in the soil of petrochemical-contaminated waste sites. In total, 573 wild cotton rats (Sigmodon hispidus) were examined. The rats that were seasonally collected from 12 contaminated and 12 ecologically matched reference sites across Oklahoma over a 3-yr period. The risks of cotton rats exposed to fluoride were analyzed by means of gross examination, histopathology, and scanning electron microscopy of rat incisors. Cotton rats from reference sites showed no pathologic changes in incisors (98%). In comparison, 46% of cotton rats from contaminated sites had various degrees of dental lesions. The prevalence and severity of dental lesions in cotton rats from contaminated sites were significantly influenced by season. There was a 45% increase in prevalence and a 65% increase in severity of dental lesions from summer to winter. This study demonstrated that cotton rats are very sensitive biomonitors for assessing toxicity risks from soils contaminated with fluoride and that such assessments should consider seasonal influences.

Evaluation of myelotoxicity in cotton rats (Sigmodon hispidus) exposed to environmental contaminants. II. Myelotoxicity associated with petroleum industrial wastes.

Various chemical mixtures exist in soil contaminated with petrochemical wastes, yet no comprehensive assessment of their impact on terrestrial ecosystems has been conducted. The purpose of this study was to evaluate hematotoxicity risks to wild populations of cotton rats (Sigmodon hispidus) residing in habitats previously contaminated by petroleum industrial wastes. Resident cotton rats were monitored on nine contaminated sites and nine ecologically matched reference sites in Oklahoma. The possible toxicological interactions of petrochemical wastes on bone marrow was investigated by using the assay of colony formation of granulocyte-macrophage progenitor cells. There was a consistent significant 21 to 39% decrease in the number of colony-forming units of granulocyte-macrophage (CFU-GM) in cotton rats from petrochemical-contaminated sites compared to matched reference sites, with no marked changes in hematological or histopathological parameters. These results suggest that bone-marrow progenitor cell culture is a sensitive indicator for the assessment of ecotoxicity risks associated with petrochemical wastes that are generated by the oil refining industry. Long-term exposure to hazardous wastes associated with the petroleum industry may represent a subtle risk to the hematopoietic system in humans.

Immunotoxicity risks associated with land-treatment of petrochemical wastes revealed using an in situ rodent model.

Land-treatment of petrochemical wastes is a widely used method to dispose of hazardous and non-hazardous waste by biodegradation. However, no comprehensive assessment of the impact of such disposal techniques on terrestrial ecosystems has been conducted. Despite the presence of suspected immunotoxicants in the soil, wild rodents frequently reside on these waste sites after closure or abandonment. We explored the seasonal sensitivity of the immune system of the hispid cotton rat (Sigmodon hispidus) to in situ exposures on sites land-treated with petrochemical wastes. Animals were monitored on five contaminated land-treatment sites and five ecologically matched-reference sites in Oklahoma, USA, over two seasons (summer and winter). Most hematological parameters were not adversely affected by land-treatment; however, platelet counts were 26% greater in cotton rats from land-treatment sites compared to reference sites in winter. Significant treatment-related differences were observed in total serum protein concentrations, organ mass and organ cellularity, but these differences were not consistent across the five land-treatment units. Lymphoproliferative responses of cotton rat splenocytes stimulated in vitro were elevated for a T-cell mitogen and depressed for a B-cell mitogen in animals from land-treatment compared to reference sites. The ability of splenocytes to proliferate in response to interleukin-2 receptor-binding was not influenced by treatment. Total yields of peritoneal cells, yield of peritoneal macrophages, and yield of peritoneal lymphocytes were influenced to varying degrees by land-treatment. Functionally, in vitro metabolic activity of peritoneal macrophages was 114% greater in cotton rats from land-treatment sites compared to reference sites during summer. These results indicate that petrochemical wastes applied to soils on these five land-treatment sites had variable immunomodulatory effects in resident cotton rats. Immune alterations for some assays were indicative of enhancement on some land-treatment sites while suppressive on other land-treatment sites, which could have been a function of type and concentration of immunotoxicants present on each site and highlights the uniqueness of each land-treatment site.

Efficacy of histopathology in detecting petrochemical-induced toxicity in wild cotton rats (Sigmodon hispidus).

A variety of chemical mixtures exist in the soil of petrochemical waste sites, and many of these compounds are known immunotoxicants that have been observed to induce immune alterations in wild rodents inhabiting many of these petrochemical waste sites. Conventional histopathological assessments have been widely used with considerable success to investigate immunotoxicity of various agents under laboratory conditions. We hypothesized that histopathologic assessments would be equally sensitive for detecting exposure to complex mixtures of toxicants in cotton rats (Sigmodon hispidus) residing in contaminated habitats. Histopathological parameters were examined from a total of 624 cotton rats that were seasonally collected from 13 petrochemical-contaminated waste sites and 13 ecologically matched reference sites in Oklahoma over a 3-year period. Histopathological examination did not reveal any lesion associated with exposure to petrochemical wastes except renal inclusion bodies. Prevalence and severity of histologic lesions in liver and kidneys of cotton rats were significantly influenced by season, where prevalence and severity were lower in winter than summer on all study sites. These results suggest that the evaluation of toxicity from exposure to contaminants in the soil of industrial waste sites using histopathological assessments is not sensitive enough to detect exposure to the low levels of environmental contaminants present on most waste sites.

Tumoricidal activity of lymphokine-activated killer cells during acute protein restriction in the cotton rat (Sigmodon hispidus).

Habitat-induced alterations of immune system function have been implicated in the regulation of survival rates in wild herbivore populations. Protein availability in the diet has been shown to fluctuate with density and influence immunity in hispid cotton rats (Sigmodon hispidus), a common herbivorous rodent of the southeastern United States. In this study, we examined the impact of short-term, moderate restrictions in dietary protein on the tumoricidal activity of lymphokine-activated killer (LAK) cells in the spleen of subadult male cotton rats in captivity. Animals were fed complete, isocaloric diets containing either 20% casein (high quality diet), or one of three moderate levels of protein (10, 8, or 5% casein) for two weeks prior to assessing LAK cell activity in vitro in the presence of YAC-1 tumor cells. Moderate restrictions in protein resulted in depressed body growth, although all animals gained mass during the second week of the trial, without significant increases in food intake. Immune organ development and cellularity were suppressed in moderately restricted cotton rats when compared to those on a high quality diet. Tumoricidal activity of LAK cells against YAC-1 targets were significantly altered by diet treatments, being elevated in the group fed a diet containing 10% casein. There was a general tendency for increased LAK cell activity among those fed one of the three moderate quality diets, but observed suppressions in splenic cellularity tended to result in a slight decline in total lytic capacity of spleens.

The feeding behaviour of Psoroptes spp. mites on rabbits and sheep.

A scanning electron microscope (SEM) study of the mouthparts of Psoroptes cuniculi from rabbits and P. ovis from sheep established that they are identical in morphology and are adapted for surface feeding rather than piercing the epidermis. Haemoglobin was found in both P. cuniculi and P. ovis on rabbits but not in P. ovis on sheep and it is concluded that the haemoglobin is derived from small haemorrhages on the surface of inflamed rabbit skin. This inflammation is caused by the deposition of antigenic material on the skin which is abraded by the mite mouthparts. The mites feed on the resulting exudate and on other surface material. An immunofluorescent assay revealed that the 2 mite species are antigenically similar.

Fluorosis risks to resident hispid cotton rats on land-treatment facilities for petrochemical wastes.

Land-treatment of petroleum wastes is a widely used industrial practice, yet there has been no comprehensive evaluation of the long-term risks to human or terrestrial ecosystems from such practices. We evaluated cotton rat (Sigmodon hispidus) populations on three sites in Oklahoma (USA) that historically used land-treatment for disposal of various petroleum wastes (July 1995-March 1997). Average concentrations of fluoride in soil from these sites ranged from 878 to 4317 mg/kg. A census of resident cotton rats on land-treatment sites revealed a high incidence (40% overall) of dental lesions compared to reference populations (<1% dental lesions). During winter there was a 34% to 65% increase compared to summer in frequency of dental lesions in cotton rats on two of the three land-treatment sites. Incidence of dental lesions on two land-treatment sites was greater (9-16%) in female cotton rats compared to males. Cotton rats from land-treatment sites had higher concentrations of fluoride in bone and greater severity of dental lesions compared to reference animals. Dental lesions were considered to be most consistent with dental fluorosis because of elevated fluoride in bone. Neither concentration of fluoride in soil nor level of fluoride in bone was a good predictor of severity of dental lesions in cotton rats on land-treatment sites.

Implications of the theory/practice gap for Project 2000 students.

Nursing has frequently attempted to address the gap between theory and practice. This article explores their relationship and the implications of any theory/practice gap for emergent Project 2000 students.