Independent and Stochastic Action of DNA Polymerases in the Replisome.

It has been assumed that DNA synthesis by the leading- and lagging-strand polymerases in the replisome must be coordinated to avoid the formation of significant gaps in the nascent strands. Using real-time single-molecule analysis, we establish that leading- and lagging-strand DNA polymerases function independently within a single replisome. Although average rates of DNA synthesis on leading and lagging strands are similar, individual trajectories of both DNA polymerases display stochastically switchable rates of synthesis interspersed with distinct pauses. DNA unwinding by the replicative helicase may continue during such pauses, but a self-governing mechanism, where helicase speed is reduced by ∼80%, permits recoupling of polymerase to helicase. These features imply a more dynamic, kinetically discontinuous replication process, wherein contacts within the replisome are continually broken and reformed. We conclude that the stochastic behavior of replisome components ensures complete DNA duplication without requiring coordination of leading- and lagging-strand synthesis. PAPERCLIP.

Cell sorting by active forces in a phase-field model of cell monolayers.

Cell sorting, the segregation of cells with different properties into distinct domains, is a key phenomenon in biological processes such as embryogenesis. We use a phase-field model of a confluent cell layer to study the role of activity in cell sorting. We find that a mixture of cells with extensile or contractile dipolar activity, and which are identical apart from their activity, quickly sort into small, elongated patches which then grow slowly in time. We interpret the sorting as driven by the different diffusivity of the extensile and contractile cells, mirroring the ordering of Brownian particles connected to different hot and cold thermostats. We check that the free energy is not changed by either partial or complete sorting, thus confirming that activity can be responsible for the ordering even in the absence of thermodynamic mechanisms.

Inpatient Rehabilitation Facility Ownership Type Yields Mixed Performances on Quality Measures.

OBJECTIVE: To evaluate the effects of inpatient rehabilitation facility (IRF) ownership type on IRF-Quality Reporting Program (IRF-QRP) measures. DESIGN: Cross-sectional, observational design. SETTING: We used 2 Centers for Medicare and Medicare publicly-available, facility-level data sources: (1) IRF compare files and (2) IRF rate setting files - final rule. Data from 2021 were included. PARTICIPANTS: The study sample included 1092 IRFs (N=1092). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We estimated the effects of IRF ownership type, defined as for-profit and nonprofit, on 15 IRF-QRP measures using general linear models. Models were adjusted for the following facility-level characteristics: (1) Centers for Medicare and Medicaid census divisions; (2) number of discharges; (3) teaching status; (4) freestanding vs hospital unit; and (5) estimated average weight per discharge. RESULTS: Ownership type was significantly associated with 9 out of the fifteen IRF-QRP measures. Nonprofit IRFs performed better with having lower readmissions rates within stay and 30-day post discharge. For-profit IRFs performed better for all the functional measures and with higher rates of returning to home and the community. Lastly, for-profit IRFs spent more per Medicare beneficiary. CONCLUSIONS: Ideally, IRF performance would not vary based on ownership type. However, we found that ownership type is associated with IRF-QRP performance scores. We suggest that future studies investigate how ownership type affects patient-level outcomes and the longitudinal effect of ownership type on IRF-QRP measures.

The potential role of biofilms in promoting fouling formation in radioactive discharge pipelines.

Nuclear facility discharge pipelines accumulate inorganic and microbial fouling and radioactive contamination, however, research investigating the mechanisms that lead to their accumulation is limited. Using the Sellafield discharge pipeline as a model system, this study utilised modified Robbins devices to investigate the potential interplay between inorganic and biological processes in supporting fouling formation and radionuclide uptake. Initial experiments showed polyelectrolytes (present in pipeline effluents), had minimal effects on fouling formation. Biofilms were, however, found to be the key component promoting fouling, leading to increased uptake of inorganic particulates and metal contaminants (Cs, Sr, Co, Eu and Ru) compared to a non-biofilm control system. Biologically-mediated uptake mechanisms were implicated in Co and Ru accumulation, with a potential bioreduced Ru species identified on the biofilm system. This research emphasised the key role of biofilms in promoting fouling in discharge pipelines, advocating for the use of biocide treatments methods.

Are Social Determinants of Health Associated With Onset of Rehabilitation Services in Patients Hospitalized for Traumatic Brain Injury?

OBJECTIVE: To examine the impact of community-level social determinants of health (SDoH) on the onset of occupational therapy (OT) and physical therapy (PT) services among individuals hospitalized for traumatic brain injury (TBI). SETTING: 14 acute care hospitals in the state of Colorado. PARTICIPANTS: We studied 5825 adults with TBI. DESIGN: In a secondary analysis of de-identified electronic health record data, we performed multivariable logistic and linear regressions to calculate odds ratios (ORs) and 95% CIs for the likelihood of receiving services and duration to initiation of services among those who received them. MAIN MEASURES: Community-level SDoH, receipt of rehabilitation services, and onset of rehabilitation services. RESULTS: Multivariable logistic and linear regressions revealed that those in top quartiles for community income were associated with duration to OT services, ranging from OR = 0.33 [05% CI, 0.07, 0.60] for quartile 2 to 0.76 [0.44, 1.08] for quartile 4 compared with those with the lowest quartile. Only the top quartile differed significantly for duration to PT services (0.63 [0.28, 0.98]). Relative to those with below the median community percentage of high school degree, those with above the median were associated with duration to PT services only (-0.32 [-0.60, -0.04]). Neither community percentage with bachelor's degree nor rural-urban designation was associated with duration to either therapy service. CONCLUSION: Further research is needed to determine whether our SDoH variables were too diffuse to capture individual experiences and impacts on care or whether community-level education and income, and rurality, truly do not influence time to therapy for patients hospitalized with TBI. Other, individual-level variables, such as age, comorbidity burden, and TBI severity, demonstrated clear relationships with therapy onset. These findings may help therapists evaluate and standardize equitable access to timely rehabilitation services.

Compact Back-End Electronics with Temperature Compensation and Efficient Data Management for In Situ SiPM-Based Radiation Detection.

A compact back-end interface for silicon photomultipliers (SiPMs) implementing Zener diode-based temperature compensation has been developed for the remote detection of beta and gamma radiation. Remote detection is facilitated by the development of an efficient data management system utilising MySQL database storage for recording periodic spectra data for wireless access over a private Wi-Fi network. A trapezoidal peak shaping algorithm has been implemented on an FPGA for the continuous conversation of pulses from the SiPM, signifying the detection of a radiological particle, into spectra. This system has been designed to fit within a 46 mm cylindrical diameter for in situ characterization, and can be attached to one or more SiPMs used in conjunction with a range of scintillators. LED blink tests have been used to optimise the trapezoidal shaper coefficients to maximise the resolution of the recorded spectra. Experiments with an array of SiPMs integrated with a NaI(Tl) scintillator exposed to sealed sources of Co-60, Cs-137, Na-22 and Am-241 have shown that the detector achieves a peak efficiency of 27.09 ± 0.13% for a gamma peak at 59.54 keV produced by Am-241, and a minimum energy resolution (Delta E/E) of 4.27 ± 1.16% for the 1332.5 keV gamma peak from Co-60.

Predicting Receipt and Types of Occupational Therapy Services for Patients with Arousal Deficits in the Neuro Critical Care Unit.

Occupational therapy has been identified as a required service in the neuro critical care unit (NCCU), however who receives occupational therapy services and what services they receive are not well understood. We sought to determine if arousal deficits impacted patients' likelihood to receive an occupational therapy evaluation or specific types of occupational therapy interventions in the NCCU. When compared to patients without arousal deficits, patients who were experiencing agitation or light sedation, but not deep sedation, were more likely to receive occupational therapy interventions in the therapeutic activities category. Arousal deficits were not associated with receipt of occupational therapy services or occupational therapy interventions in the self-care or therapeutic exercise categories. Determining predictors of occupational therapy services will help ensure the timely delivery of services by improving the allocation of resources and identifying potential gaps in care.

Mobility Status and Acute Care Physical Therapy Utilization: The Moderating Roles of Age, Significant Others, and Insurance Type.

OBJECTIVE: To investigate whether a direct measure of need for physical therapy (PT), mobility status, was associated with acute care PT utilization and whether this relationship differs across sociodemographic factors and insurance type. DESIGN: In a secondary analysis of electronic health records data, we estimated logistic regression models to determine whether mobility status was associated with acute care PT utilization. Interactions between mobility and both sociodemographic factors (sex, age, significant other, minority status) and insurance type were included to investigate whether the relationship between mobility and PT utilization varied across patient characteristics. SETTING: Five regional hospitals from 1 health system. PARTICIPANTS: A total of 60,459 adults admitted between 2014 and 2018 who received a PT evaluation. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Received acute care PT; Activity Measure for Post-Acute Care "6-Clicks" measure of mobility. RESULTS: Half of patients who received a PT evaluation received subsequent treatment. Patients with mobility limitations were more likely to receive PT. Interaction terms indicated that among patients with mobility limitations, those who (1) were younger, (2) had significant others, and (3) had private insurance (vs public) were more likely to receive PT. Among patients with greater mobility status, older patients and those without a significant other were more likely to receive PT. CONCLUSIONS: The relationship between acute care PT need and utilization differed across sociodemographic factors and insurance type. We offer potential explanations for these findings to guide efforts targeting equitable distribution of beneficial PT services.

Cryo-scanning electron microscopy demonstrates that ice morphology is not associated with the post-thaw survival of domestic boar (Sus domesticus) spermatozoa: A comparison of directional and conventional freezing methods.

Directional freezing (in 2 or 10 ml hollow glass tubes) has been reported to improve post-thaw sperm survival parameters compared to conventional methods (in 0.5 ml straws). However, the biophysical properties that increase post-thaw survival are poorly understood. Therefore, the aim for the current study was to investigate the effect of ice morphology on the post-thaw survival of domestic boar spermatozoa directionally and conventionally cryopreserved in 0.5 ml straws. Ice morphology was quantitatively analyzed using a combination of cryo-scanning electron microscopy and Fiji Shape Descriptors. Multivariate analysis found a significant, non-linear effect (p < 0.05) of interface velocity on ice morphology, with an increase in both ice-lake size, as indicated by area and in aspect ratio, at an interface velocity of 0.2 mm/s. By contrast, post-thaw sperm survival (defined as spermatozoa with both intact plasma membranes and acrosomes) was biphasic, with peaks of survival at interface velocities of 0.2 mm/s (54.2 ± 1.9%), and 1.0 or 1.5 mm/s (56.5 ± 1.5%, 56.7 ± 1.7% respectively), and lowest survival at 0.5 (52.1 ± 1.6%) and 3.0 mm/s (51.4 ± 1.9%). Despite numerical differences in Shape Descriptors, there was no difference (p > 0.05) in the post-thaw survival between conventionally and directionally cryopreserved samples at optimal interface velocities of 1.0 or 1.5 mm/s. These findings suggest that: 1) ice morphology has little impact on post-thaw survival of boar spermatozoa, and 2) directional freezing in 0.5 ml straws (rather than 2 or 10 ml hollow glass tubes) may attenuate benefits of directional freezing.

Developing field-scale, gentle remediation options for nuclear sites contaminated with 137Cs and 90Sr: The role of Nature-Based Solutions.

The remediation of contaminated land using plants, bacteria and fungi has been widely examined, especially in laboratory or greenhouse systems where conditions are precisely controlled. However, in real systems at the field scale conditions are much more variable and often produce different outcomes, which must be fully examined if 'gentle remediation options', or GROs, are to be more widely implemented, and their associated benefits (beyond risk-management) realized. These secondary benefits can be significant if GROs are applied correctly, and can include significant biodiversity enhancements. Here, we assess recent developments in the field-scale application of GROs for the remediation of two model contaminants for nuclear site remediation (90Sr and 137Cs), their risk management efficiency, directions for future application and research, and barriers to their further implementation at scale. We also discuss how wider benefits, such as biodiversity enhancements, water filtration etc. can be maximized at the field-scale by intelligent application of these approaches.

Activities of Daily Living Performance and Acute Care Occupational Therapy Utilization: Moderating Factors.

IMPORTANCE: Hospitalized patients who have difficulty performing activities of daily living (ADLs) benefit from occupational therapy services; however, disparities in access to such services are understudied. OBJECTIVE: To investigate whether need (i.e., limited ADL performance) predicts acute care occupational therapy utilization and whether this relationship differs across sociodemographic factors and insurance type. DESIGN: A secondary analysis of electronic health records data. Logistic regression models were specified to determine whether ADL performance predicted use of occupational therapy treatment. Interactions were included to investigate whether the relationship between ADL performance and occupational therapy utilization varied across sociodemographic factors (e.g., age) and insurance type. PARTICIPANTS: A total of 56,022 adults admitted to five regional hospitals between 2014 and 2018 who received an occupational therapy evaluation. INTERVENTION: None. Outcomes and Measures: Occupational therapy service utilization, Activity Measure for Post-Acute Care "6-Clicks" measure of daily activity. RESULTS: Forty-four percent of the patients evaluated for occupational therapy received treatment. Patients with lower ADL performance were more likely to receive occupational therapy treatment; however, interaction terms indicated that, among patients with low ADL performance, those who were younger, were White and non-Hispanic, had significant others, and had private insurance (vs. public) were more likely to receive treatment. These differences were smaller among patients with greater ADL performance. CONCLUSIONS AND RELEVANCE: Greater need was positively associated with receiving occupational therapy services, but this relationship was moderated by age, minoritized status, significant other status, and insurance type. The findings provide direction for exploring determinants of disparities in occupational therapy utilization. What This Article Adds: Acute care occupational therapy utilization is driven partly by patient need, but potential disparities in access to beneficial services may exist across sociodemographic characteristics and insurance type. Identifying potential determinants of disparities in acute care occupational therapy utilization is the first step in developing strategies to reduce barriers for those in need.

Activities of Daily Living Performance and Acute Care Occupational Therapy Utilization: Moderating Factors.

IMPORTANCE: Hospitalized patients who have difficulty performing activities of daily living (ADLs) benefit from occupational therapy services; however, disparities in access to such services are understudied. OBJECTIVE: To investigate whether need (i.e., limited ADL performance) predicts acute care occupational therapy utilization and whether this relationship differs across sociodemographic factors and insurance type. DESIGN: A secondary analysis of electronic health records data. Logistic regression models were specified to determine whether ADL performance predicted use of occupational therapy treatment. Interactions were included to investigate whether the relationship between ADL performance and occupational therapy utilization varied across sociodemographic factors (e.g., age) and insurance type. PARTICIPANTS: A total of 56,022 adults admitted to five regional hospitals between 2014 and 2018 who received an occupational therapy evaluation. INTERVENTION: None. Outcomes and Measures: Occupational therapy service utilization, Activity Measure for Post-Acute Care "6-Clicks" measure of daily activity. RESULTS: Forty-four percent of the patients evaluated for occupational therapy received treatment. Patients with lower ADL performance were more likely to receive occupational therapy treatment; however, interaction terms indicated that, among patients with low ADL performance, those who were younger, were White and non-Hispanic, had significant others, and had private insurance (vs. public) were more likely to receive treatment. These differences were smaller among patients with greater ADL performance. CONCLUSIONS AND RELEVANCE: Greater need was positively associated with receiving occupational therapy services, but this relationship was moderated by age, minoritized status, significant other status, and insurance type. The findings provide direction for exploring determinants of disparities in occupational therapy utilization. What This Article Adds: Acute care occupational therapy utilization is driven partly by patient need, but potential disparities in access to beneficial services may exist across sociodemographic characteristics and insurance type. Identifying potential determinants of disparities in acute care occupational therapy utilization is the first step in developing strategies to reduce barriers for those in need.

Predicting Community Discharge for Occupational Therapy Recipients in the Neurological Critical Care Unit.

IMPORTANCE: Occupational therapy in the neurological critical care unit (NCCU) may enable safe community discharge by restoring functional ability. However, the influence of patient characteristics and NCCU occupational therapy on discharge disposition is largely unknown. OBJECTIVE: To examine how patient factors and receipt of occupational therapy predict discharge disposition for NCCU patients. DESIGN: Retrospective cross-sectional cohort study of electronic health records data from adults admitted to the NCCU between May 2013 and September 30, 2015. SETTING: NCCU in a large urban academic hospital. PARTICIPANTS: Adults age 18 yr or older (N = 1,134) admitted to the NCCU. Outcomes and Measures: Using logistic regression with discharge disposition as the dependent variable, we entered sex, age, length of stay (LOS), baseline Glasgow Coma Scale score, Elixhauser Comorbidity Index, and receipt of occupational therapy services as predictor variables. RESULTS: Of NCCU patients, 39% received occupational therapy. Younger age, shorter LOS, lower comorbidity burden, and not receiving occupational therapy services increased the likelihood of discharge to the community. Men who received occupational therapy were less likely to be discharged to the community than men who did not receive occupational therapy. As age increased, differences in the probability of community discharge decreased between recipients and nonrecipients of occupational therapy services. CONCLUSIONS AND RELEVANCE: Our results suggest that patients receiving occupational therapy services in the NCCU may have a lower likelihood of community discharge. However, these findings may result from therapist's consideration of the safest discharge location to ensure the greatest balance between independence and support. What This Article Adds: This study's findings suggest that receipt of occupational therapy in the NCCU is associated with higher likelihood for noncommunity discharge (i.e., to inpatient rehabilitation, skilled nursing, or long-term care). However, activity limitations and comorbidity burden may be greater for recipients of occupational therapy, and these NCCU patients are presumably less prepared for community discharge.

Hyperpolarized NMR study of the impact of pyruvate dehydrogenase kinase inhibition on the pyruvate dehydrogenase and TCA flux in type 2 diabetic rat muscle.

The role of pyruvate dehydrogenase in mediating lipid-induced insulin resistance stands as a central question in the pathogenesis of type 2 diabetes mellitus. Many researchers have invoked the Randle hypothesis to explain the reduced glucose disposal in skeletal muscle by envisioning an elevated acetyl CoA pool arising from increased oxidation of fatty acids. Over the years, in vivo NMR studies have challenged that monolithic view. The advent of the dissolution dynamic nuclear polarization NMR technique and a unique type 2 diabetic rat model provides an opportunity to clarify. Dynamic nuclear polarization enhances dramatically the NMR signal sensitivity and allows the measurement of metabolic kinetics in vivo. Diabetic muscle has much lower pyruvate dehydrogenase activity than control muscle, as evidenced in the conversion of [1-13C]lactate and [2-13C]pyruvate to HCO3- and acetyl carnitine. The pyruvate dehydrogenase kinase inhibitor, dichloroacetate, restores rapidly the diabetic pyruvate dehydrogenase activity to control level. However, diabetic muscle has a much larger dynamic change in pyruvate dehydrogenase flux than control. The dichloroacetate-induced surge in pyruvate dehydrogenase activity produces a differential amount of acetyl carnitine but does not affect the tricarboxylic acid flux. Further studies can now proceed with the dynamic nuclear polarization approach and a unique rat model to interrogate closely the biochemical mechanism interfacing oxidative metabolism with insulin resistance and metabolic inflexibility.

Chronic hindbrain administration of oxytocin elicits weight loss in male diet-induced obese mice.

Previous studies indicate that oxytocin (OT) administration reduces body weight in high-fat diet (HFD)-induced obese (DIO) rodents through both reductions in food intake and increases in energy expenditure. We recently demonstrated that chronic hindbrain [fourth ventricular (4V)] infusions of OT evoke weight loss in DIO rats. Based on these findings, we hypothesized that chronic 4V OT would elicit weight loss in DIO mice. We assessed the effects of 4V infusions of OT (16 nmol/day) or vehicle over 28 days on body weight, food intake, and body composition. OT reduced body weight by approximately 4.5% ± 1.4% in DIO mice relative to OT pretreatment body weight (P < 0.05). These effects were associated with reduced adiposity and adipocyte size [inguinal white adipose tissue (IWAT)] (P < 0.05) and attributed, in part, to reduced energy intake (P < 0.05) at a dose that did not increase kaolin intake (P = NS). OT tended to increase uncoupling protein-1 expression in IWAT (0.05 < P < 0.1) suggesting that OT stimulates browning of WAT. To assess OT-elicited changes in brown adipose tissue (BAT) thermogenesis, we examined the effects of 4V OT on interscapular BAT temperature (TIBAT). 4V OT (1 µg) elevated TIBAT at 0.75 (P = 0.08), 1, and 1.25 h (P < 0.05) postinjection; a higher dose (5 µg) elevated TIBAT at 0.75-, 1-, 1.25-, 1.5-, 1.75- (P < 0.05), and 2-h (0.05 < P < 0.1) postinjection. Together, these findings support the hypothesis that chronic hindbrain OT treatment evokes sustained weight loss in DIO mice by reducing energy intake and increasing BAT thermogenesis at a dose that is not associated with evidence of visceral illness.

The Relationship Between Fall Risk and Hospital-Based Therapy Utilization Is Moderated by Demographic Characteristics and Insurance Type.

OBJECTIVE: To investigate whether indicators of patient need (comorbidity burden, fall risk) predict acute care rehabilitation utilization, and whether this relation varies across patient characteristics (ie, demographic characteristics, insurance type). DESIGN: Secondary analysis of electronic health records data. SETTING: Five acute care hospitals. PARTICIPANTS: Adults (N=110,209) admitted to 5 regional hospitals between 2014 and 2018. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Occupational therapy (OT) and physical therapy (PT) utilization. Logistic regression models determined whether indicators of patient need predicted OT and PT utilization. Interactions between indicators of need and both demographic factors (eg, minority status, presence of significant other) and insurance type were included to investigate whether the relation between patient need and therapy access varied across patient characteristics. RESULTS: Greater comorbidity burden was associated with a higher likelihood of receiving OT and PT. Relative to those with low fall risk, those with moderate and high fall risk were more likely to receive OT and PT. The relation between fall risk and therapy utilization differed across patient characteristics. Among patients with higher levels of fall risk, those with a significant other were less likely to receive OT and PT; significant other status did not explain therapy utilization among patients with low fall risk. Among those with high fall risk, patients with VA insurance and minority patients were more likely to receive PT than those with private insurance and nonminority patients, respectively. Insurance type and minority status did not appear to explain PT utilization among those with lower fall risk. CONCLUSIONS: Patients with greater comorbidity burden and fall risk were more likely to receive acute care rehabilitation. However, the relation between fall risk and utilization was moderated by insurance type, having a significant other, and race/ethnicity. Understanding the implications of these utilization patterns requires further research.

Relative Contribution of Windbreak, Copper Sprays, and Leafminer Control for Citrus Canker Management and Prevention of Crop Loss in Sweet Orange Trees.

The management of citrus canker, caused by Xanthomonas citri subsp. citri, has been widely studied in endemic areas because of the importance of the disease in several citrus-producing countries. A set of control measures is well established, but no study has investigated the efficiency of each measure individually and their combination for disease suppression. This study comprised a 3-year field study to assess the relative contribution of three measures for the control of citrus canker and reduction of crop losses. Windbreak (Wb), copper sprays (Cu), and leafminer control (Lc) were assessed in eight different combinations in a split-split plot design. The orchard was composed of 'Valencia' sweet orange trees grafted onto 'Rangpur' lime. Casuarina cunninghamiana trees were used as Wb. Cu and Lc sprays were performed every 21 days throughout the year. Individually, Cu showed the highest contribution for canker control, followed by Wb. Lc had no effect on reducing citrus canker. Wb+Cu showed the highest efficiency for control of the disease. This combination reduced the incidence of diseased trees by approximately 60%, and the incidence of diseased leaves and fruit by ≥90% and increased the yield in 2.0- to 2.6-fold in comparison with the unmanaged plots. Cu sprays were important for reducing disease incidence and crop losses, whereas Wb had an additional contribution in minimizing the incidence of cankered, non-marketable fruit. The results indicated that the adoption of these measures of control may depend on the characteristics of the orchard and destination of the production.

The Simulated Characterization and Suitability of Semiconductor Detectors for Strontium 90 Assay in Groundwater.

This paper examines the potential deployment of a 10 mm × 10 mm × 1 mm cadmium telluride detector for strontium-90 measurement in groundwater boreholes at nuclear decommissioning sites. Geant4 simulation was used to model the deployment of the detector in a borehole monitoring contaminated groundwater. It was found that the detector was sensitive to strontium-90, yttrium-90, caesium-137, and potassium-40 decay, some of the significant beta emitters found at Sellafield. However, the device showed no sensitivity to carbon-14 decay, due to the inability of the weak beta emission to penetrate both the groundwater and the detector shielding. The limit of detection for such a sensor when looking at solely strontium-90 decay was calculated as 323 BqL-1 after a 1-h measurement and 66 BqL-1 after a 24-h measurement. A gallium-arsenide (GaAs) sensor with twice the surface area, but 0.3% of the thickness was modelled for comparison. Using this sensor, sensitivity was increased, such that the limit of detection for strontium-90 was 91 BqL-1 after 1 h and 18 BqL-1 after 24 h. However, this sensor sacrifices the potential to identify the present radionuclides by their end-point energy. Additionally, the feasibility of using flexible detectors based on solar cell designs to maximise the surface area of detectors has been modelled.

The Simulation of In-Situ Groundwater Detector Response as a Means of Identifying Beta Emitting Radionuclides by Linear Regression Analysis.

The in-situ characterisation of strontium-90 contamination of groundwater at nuclear decommissioning sites would represent a novel and cost-saving technology for the nuclear industry. However, beta particles are emitted over a continuous spectrum and it is difficult identify radionuclides due to the overlap of their spectra and the lack of characteristic features. This can be resolved by using predictive modelling to perform a maximum-likelihood estimation of the radionuclides present in a beta spectrum obtained with a semiconductor detector. This is achieved using a linear least squares linear regression and relating experimental data with simulated detector response data. In this case, by simulating a groundwater borehole scenario and the deployment of a cadmium telluride detector within it, it is demonstrated that it is possible to identify the presence of 90Sr, 90Y, 137Cs and 235U decay. It is determined that the optimal thickness of the CdTe detector for this technique is in the range of 0.1 to 1 mm. The influence of suspended solids in the groundwater is also investigated. The average and maximum concentrations of suspended particles found at Sellafield do not significantly deteriorate the results. It is found that applying the linear regression over two energy windows improves the estimate of 90Sr activity in a mixed groundwater source. These results provide validation for the ability of in-situ detectors to determine the activity of 90Sr in groundwater in a timely and cost-effective manner.

Occupational Therapist Treatment of Patients in the Neurological Critical Care Unit: Utilization and Patient Characteristics.

IMPORTANCE: Occupational therapy use in the neurological critical care unit (NCCU) may relate to patient factors, but data about these relationships remain unpublished. OBJECTIVE: To examine how patient factors predict NCCU occupational therapy use and intervention types. DESIGN: Retrospective cohort study of electronic health records data from adults admitted to the NCCU between May 2013 and September 2015. SETTING: NCCU in a large, urban academic hospital. PARTICIPANTS: Adults (age ≥18 yr; N = 1,134) admitted to the NCCU. MEASURES: Using length of stay (LOS), number of comorbidities, Glasgow Coma Scale (GCS) score, gender, age, and racial-ethnic minority status as independent variables, separate regression models identified predictors for each dependent variable: receipt of NCCU occupational therapy, occupational therapy onset (days after admission), and receipt of self-care or home management (ADL-Home); functional activities or cognitive training (Func-Cog); and therapeutic exercise (Ther-Ex). RESULTS: Four hundred twenty patients (37.0%) received occupational therapy in the NCCU. Receipt of occupational therapy was positively associated with LOS, number of comorbidities, GCS score, and age. Earlier occupational therapy onset was associated with higher GCS score and shorter LOS. Receipt of ADL-Home or Func-Cog interventions was significantly predicted by number of occupational therapy sessions, but patients with longer LOS were less likely to receive ADL-Home interventions. Receipt of Ther-Ex interventions became less likely as GCS score increased. CONCLUSIONS AND RELEVANCE: Patients are more likely to receive occupational therapy services if they are older and have a longer NCCU LOS, more comorbidities, and a higher level of consciousness. What This Article Adds: A patient's level of consciousness is clearly associated with occupational therapy utilization and hospital outcomes, but it should not be the only factor considered when prioritizing patients for NCCU occupational therapy services. Compared with patients who were more awake and alert, patients with a lower level of consciousness had a later onset of occupational therapy, which suggests an opportunity for NCCU occupational therapists to collaborate with physicians in the modification of sedation protocols to enable early rehabilitation.