Recycling of nuclear spent fuel with AIROX processing

This report examines the concept of recycling light water reactor (LWR) fuel through use of a dry-processing technique known as the AIROX (Atomics International Reduction Oxidation) process. In this concept, the volatiles and the cladding from spent LWR fuel are separated from the fuel by the AIROX process. The fuel is then reenriched and made into new fuel pins with new cladding. The feasibility of the concept is studied from a technical and high level waste minimization perspective

Reactor physics methods, models, and applications used to support the conceptual design of the Advanced Neutron Source

This report summarizes the neutronics analysis performed during 1991 and 1992 in support of characterization of the conceptual design of the Advanced Neutron Source (ANS). The methods used in the analysis, parametric studies, and key results supporting the design and safety evaluations of the conceptual design are presented. The analysis approach used during the conceptual design phase followed the same approach used in early ANS evaluations: (1) a strong reliance on Monte Carlo theory for beginning-of-cycle reactor performance calculations and (2) a reliance on few-group diffusion theory for reactor fuel cycle analysis and for evaluation of reactor performance at specific time steps over the fuel cycle. The Monte Carlo analysis was carried out using the MCNP continuous-energy code, and the few- group diffusion theory calculations were performed using the VENTURE and PDQ code systems. The MCNP code was used primarily for its capability to model the reflector components in realistic geometries as well as the inherent circumvention of cross-section processing requirements and use of energy-collapsed cross sections. The MCNP code was used for evaluations of reflector component reactivity effects and of heat loads in these components. The code was also used as a benchmark comparison against the diffusion-theory estimates of key reactor parameters such as region fluxes, control rod worths, reactivity coefficients, and material worths. The VENTURE and PDQ codes were used to provide independent evaluations of burnup effects, power distributions, and small perturbation worths. The performance and safety calculations performed over the subject time period are summarized, and key results are provided. The key results include flux and power distributions over the fuel cycle, silicon production rates, fuel burnup rates, component reactivities, control rod worths, component heat loads, shutdown reactivity margins, reactivity coefficients, and isotope production rates

Higher levels of glutamate in the associative-striatum of subjects with prodromal symptoms of schizophrenia and patients with first-episode psychosis

The glutamatergic and dopaminergic systems are thought to be involved in the pathophysiology of schizophrenia. Their interaction has been widely documented and may have a role in the neurobiological basis of the disease. The aim of this study was to compare, using proton magnetic resonance spectroscopy (1H-MRS), glutamate levels in the precommissural dorsal-caudate (a dopamine-rich region) and the cerebellar cortex (negligible for dopamine) in the following: (1) 18 antipsychotic-naïve subjects with prodromal symptoms and considered to be at ultra high-risk for schizophrenia (UHR), (2) 18 antipsychotic-naïve first- episode psychosis patients (FEP), and (3) 40 age- and sex- matched healthy controls. All subjects underwent a 1H-MRS study using a 3Tesla scanner. Glutamate levels were quantified and corrected for the proportion of cerebrospinal fluid and percentage of gray matter in the voxel. The UHR and FEP groups showed higher levels of glutamate than controls, without differences between UHR and FEP. In the cerebellum, no differences were seen between the three groups. The higher glutamate level in the precommissural dorsal-caudate and not in the cerebellum of UHR and FEP suggests that a high glutamate level (a) precedes the onset of schizophrenia, and (b) is present in a dopamine-rich region previously implicated in the pathophysiology of schizophrenia.peer-reviewe

Tau Structures

Tau is a microtubule-associated protein that plays an important role in axonal stabilization, neuronal development, and neuronal polarity. In this review, we focus on the primary, secondary, tertiary, and quaternary tau structures. We describe the structure of tau from its specific residues until its conformation in dimers, oligomers, and larger polymers in physiological and pathological situations

Diverse definitions of the early course of schizophrenia - a targeted literature review

Schizophrenia is a debilitating psychiatric disorder and patients experience significant comorbidity, especially cognitive and psychosocial deficits, already at the onset of disease. Previous research suggests that treatment during the earlier stages of disease reduces disease burden, and that a longer time of untreated psychosis has a negative impact on treatment outcomes. A targeted literature review was conducted to gain insight into the definitions currently used to describe patients with a recent diagnosis of schizophrenia in the early course of disease ('early' schizophrenia). A total of 483 relevant English-language publications of clinical guidelines and studies were identified for inclusion after searches of MEDLINE, MEDLINE In-Process, relevant clinical trial databases and Google for records published between January 2005 and October 2015. The extracted data revealed a wide variety of terminology and definitions used to describe patients with 'early' or 'recent-onset' schizophrenia, with no apparent consensus. The most commonly used criteria to define patients with early schizophrenia included experience of their first episode of schizophrenia or disease duration of less than 1, 2 or 5 years. These varied definitions likely result in substantial disparities of patient populations between studies and variable population heterogeneity. Better agreement on the definition of early schizophrenia could aid interpretation and comparison of studies in this patient population and consensus on definitions should allow for better identification and management of schizophrenia patients in the early course of their disease

Comparison of analytical transport and stochastic solutions for neutron slowing down in an infinite medium

A comparison of the numerical solutions of the transport equation describing the steady neutron slowing down in an infinite medium with constant cross sections is made with stochastic solutions obtained from tracking successive neutron histories in the same medium. The transport equation solution is obtained using a numerical Laplace transform inversion algorithm. The basis for the algorithm is an evaluation of the Bromwich integral without analytical continuation. Neither the transport nor the stochastic solution is limited in the number of scattering species allowed. The medium may contain an absorption component as well

Measurement of single chain neutron scattering in concentrated polymer solutions Work supported in part by the National Science Foundation Grants Nos. DMR-76-80152 and DMR 76-23697.

For some time there have been measurements of single-chain form factors for small-angle neutron scattering (SANS) in bulk polymers and in concentrated solutions. These were done by mixing a fraction of completely deuterated polymer with the normal polymer. Until recently, it was believed that these experiments had to be performed using a small fraction of deuterated polymer to avoid interchain interference effects. However, the work of Williams et al. has shown that these experiments are better if one uses large fractions of marked polymer and determines both the single chain and interference contributions to the SANS cross section. We generalize the technique of Williams et al. somewhat and apply it to the measurement of the radius of gyration of polyisoprene in the bulk.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38666/1/180180417_ftp.pd

A Rare Case of Fungal Rhinosinusitis Caused by Scedosporium apiopermum.

Fungal rhinosinusitis (FRS) is inflammation of the paranasal sinus mucosa due to fungal infections, which can be invasive or non-invasive. The occurrence of a sphenoid mucocele with a fungal ball is rare. We report a case of sphenoid sinus mucocele with a fungal ball caused by Scedosporium apiopermum in a 32-year-old female who presented to the Emergency Department with persistent headache not relieved on medications. The radiological images showed a mucocele with clival osteomyelitis. Urgent endoscopic examination and debridement was undertaken which demonstrated a mucocele with fungal ball. Microbiological examination confirmed it to be Scedosporium apiopermum

Predicting response to cognitive training for schizophrenia using results from two studies with different outcomes

BackgroundCollaborative data sharing between research groups provides an opportunity to explore the basis for the heterogeneity in cognitive training outcomes reported in the schizophrenia literature. The current analyses focused on the contribution of site and participant characteristics to these heterogeneous outcomes.MethodsData from two independent studies, from New York (NY) and Los Angeles (LA), were combined to yield a sample of 132 outpatient adults with schizophrenia/schizoaffective disorder. While similar treatment doses, cognitive exercises and outcome measures were used, sites differed in use of coaching, group discussion and compensation. Between-site differences in participant demographic and baseline clinical characteristics were tested. Regression examined predictors of change in cognition (MCCB) and functional capacity (UPSA) which could explain site differences in treatment effects.ResultsMedium to large treatment effect size differences in MCCB and UPSA favored the NY site over LA. When the studies were combined, the effect of site was significant for both outcomes with a medium effect size difference. After controlling for background characteristics, the effect of site was reduced for both outcomes, but remained significant for cognition. Improvement in UPSA was associated with better baseline MCCB (p < 0.001), lower baseline UPSA (p < 0.001) and younger age (p = 0.019). The overall model with site, baseline scores, and participant background characteristics explained about 30% to 40% of the variance in outcomes.DiscussionParticipant and treatment characteristics are both predictive of outcomes, but treatment characteristics may be more consequential to cognitive gain, while participant characteristics may be more consequential to change in functional capacity