Use of positron emission tomography for presurgical localization of eloquent brain areas in children with seizures

Successful surgical management of a neoplastic or nonneoplastic seizure focus in close proximity to or within eloquent brain areas relies on precise delineation of the relationship between the lesion and functional brain areas. The aim of this series was to validate the usefulness and test the efficacy of noninvasive presurgical PET mapping of eloquent brain areas to predict surgical morbidity and outcome in children with seizures. To identify eloquent brain areas in 15 children (6 female and 9 male; mean age 11 years) with epileptogenic lesions PET images of regional cerebral blood flow were performed following the administration of [(15)O]water during motor, visual, articulation, and receptive language tasks. These images with coregistered magnetic resonance (MR) images were then used to delineate the anatomic relationship of a seizure focus to eloquent brain areas. Additional PET images using [18F]fluoro-2-deoxy-D-glucose (FDG) and [11C]methionine (CMET) were acquired to help localize the seizure focus, as well as characterize the lesion. Patient surgical management decisions were based on PET mapping in combination with coregistered MR images, PET-FDG findings, and the anatomic characteristics of the lesion. At follow-up 1-26 months after surgery, all patients that underwent temporal lobectomy (9 patients) and extratemporal resection (4 patients) for a neoplastic or nonneoplastic seizure focus are seizure-free with minimal postoperative morbidity. Of prime importance, no child sustained a postoperative speech or language deficit. PET imaging was also well tolerated without procedural complications. Based on PET mapping, a nonoperative approach was used for 2 children and a biopsy only was used in one child. When cortical injury involved prenatally determined eloquent cortex, PET demonstrated reorganization of language areas to new adjacent areas or even to the contralateral hemisphere. Integration of anatomical and functional data enhanced the surgical safety, defined optimal surgical approach, delineated the seizure focus from eloquent brain areas, facilitated maximum resection and optimized the timing of surgery, thereby minimizing surgical morbidity while maximizing surgical goals. PET measurements of FDG and CMET uptake were also helpful in localizing the seizure focus and grading the tumors. PET used for brain mapping in children provides the surgeon with strategic preoperative information not readily attainable with traditional invasive Wada testing or intraoperative cortical stimulation. PET mapping may also improve the outcome of extratemporal resections by allowing aggressive seizure focus resection. In addition, serial brain maps may optimize timing for surgical intervention by demonstrating reorganization of eloquent cortex often seen in younger children after cortical injury. Our results suggest that noninvasive presurgical brain mapping has the potential to reduce risk and improve neurologic outcome.     

Melt-solid interactions in laser cladding and laser casting

Experimental data in conjunction with mathematical models are used to explain various aspects of laser casting and laser cladding by the preplaced powder method. For increasing speed, the data can be distinguished between substrate melting, dilution-free clad bonding, bond-free casting, and poor contact breaking the melt track into spheres. Results include a thermodynamic explanation of the wide range of process parameters over which dilution-free clad deposits can be produced, as the process switches from heating of the insulating powder to additional cooling when the melt front reaches the substrate. Also, the interaction of the melt pool with the powder bed is analyzed to identify why laser castings have microscopically uneven surfaces and do not bind with the substrate. The advancement of the melt front through the powder layer is governed by heating, melting, and incorporation of each individual grain. Although most powder grains are in the small size range for the case studied, the few particles up to a factor 3 larger delay and therefore govern the front advancement due to much slower melting and surface tension driven incorporation, depending on the particle size in a non-linear manner.     

On the role of positive and negative affectivity in job performance: A meta-analytic investigation.

Although interest regarding the role of dispositional affect in job behaviors has surged in recent years, the true magnitude of affectivity's influence remains unknown. To address this issue, the authors conducted a qualitative and quantitative review of the relationships between positive and negative affectivity (PA and NA, respectively) and various performance dimensions. A series of meta-analyses based on 57 primary studies indicated that PA and NA predicted task performance in the hypothesized directions and that the relationships were strongest for subjectively rated versus objectively rated performance. In addition, PA was related to organizational citizenship behaviors but not withdrawal behaviors, and NA was related to organizational citizenship behaviors, withdrawal behaviors, counterproductive work behaviors, and occupational injury. Mediational analyses revealed that affect operated through different mechanisms in influencing the various performance dimensions. Regression analyses documented that PA and NA uniquely predicted task performance but that extraversion and neuroticism did not, when the four were considered simultaneously. Discussion focuses on the theoretical and practical implications of these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of the properties of the nuclei used on the new generation reactor technology systems

The main application fields of the fast neutrons are accelerator-driven subcritical systems (ADS) and fusion–fission (hybrid) reactor systems for fission energy production. Thorium (Th) and uranium (U) are nuclear fuels in these reactor systems. Lead (Pb), bismuth (Bi) and tungsten (W) are the target nuclei in the ADS reactor systems. The technical design of ADS and hybrid reactor systems require much effort and data. The Hartree–Fock (H–F) method with an effective interaction with Skyrme forces is widely used for studying the properties of nuclei such as binding energy, root mean square (RMS) charge radii, mass radii, neutron density, proton density, electromagnetic multipole moments, etc. In this study, by using H–F method with interaction Skyrme RMS charge radii, RMS mass radii, neutron density and proton density were calculated for the ²³²Th, ²³⁸U, ²⁰⁷Pb, ²⁰⁹Bi and ¹⁸⁴W isotopes. The calculation results of charge radii were compared with experimental data. Obtained RMS mass radii, neutron density and proton density results were discussed for ADS and hybrid reactor systems.     

Pregnancy-associated thrombocytopenia revisited: assessment and follow-up of 50 cases

Thrombocytopenia detected during pregnancy addresses the issue of its mechanism and of the possible occurrence of neonatal thrombocytopenia. To further investigate these issues, 50 women referred to us because of thrombocytopenia detected during pregnancy (platelet count, <150 x 10(9)/L), were extensively studied, as well as their offspring. Among these thrombocytopenic women, we used the threshold of 70 x 10(9)/L to differentiate between mild and severe thrombocytopenia. Whatever the severity of thrombocytopenia, we found biological features of an autoimmune disorder in 48% of the women, and chronic thrombocytopenia in 55%. A familial thrombocytopenia was evidenced in 1 case. These 50 women gave birth to 63 neonates, among whom 24 were thrombocytopenic, either at birth or during the first week of life. Neonatal thrombocytopenia could only be predicted in multiparous women, on the basis of previous neonatal thrombocytopenia in older siblings, and/or when maternal platelet life span study, performed before pregnancy, had evidenced an autoimmune thrombocytopenia (AITP)-like profile. These results suggest that, in case of pregnancy-associated thrombocytopenia, familial and immunological studies, combined with postdelivery iterative platelet counts, should be performed to properly characterize the thrombocytopenia. Moreover, the platelet count of the neonate should be carefully assessed at birth and during the following days, a platelet life span study should be performed after delivery in the mother, because these two parameters are likely to bring valuable information regarding the forthcoming pregnancies and the risk of neonatal thrombocytopenia.     

Review on electrode–electrolyte solution interactions,related to cathode materials for Li-ion batteries

In this paper we review some critical aspects related to interactions between cathode materials and electrolyte solutions in lithium-ion batteries. Previous results are briefly summarized, together with the presentation of new results. This review deals with the basic anodic stability of commonly-used electrolyte solutions for Li-ion batteries (mostly based on alkyl carbonate solvents). We discuss herein the surface chemistry of the following cathode materials: LiCoO₂, V₂O₅, LiMn₂O₄, LiMn_1.5Ni_0.5O₄, LiMn_0.5Ni_0.5O₂, and LiFePO₄. The methods applied included solution studies by ICP, Raman, X-ray photoelectron and FTIR spectroscopies, and electron microscopy, all in conjunction with electrochemical techniques. General phenomena are the possible dissolution of transition metal ions from these materials, which leads to changes in the active mass and a retardation in the electrode kinetics due to the formation of blocking surface films. These phenomena are significant mostly at elevated temperatures and in electrolyte solutions containing acidic species. Water-contaminated LiPF₆ solutions can reach a high concentration of acidic species (e.g., HF), which is detrimental to the performance of materials such as LiCoO₂ and LiFePO₄. Both LiMn_1.5Ni_0.5O₄ and LiMn_0.5Ni_0.5O₂, even when used as nanomaterials, show a high stability in commonly-used electrolyte solutions at high temperatures. This stability is attributed to unique surface chemistry that is correlated to the presence of Ni ions in the lattice.     

Patient-reported symptoms after primary therapy for early prostate cancer: results of a prospective cohort study

Phosphoribosyl-ATP pyrophosphohydrolase (PRA-PH) and phosphoribosyl-AMP cyclohydrolase (PRA-CH) are encoded by HIS4 in yeast and by hisIE in bacteria and catalyze the second and the third step, respectively, in the histidine biosynthetic pathway. By complementing a hisI mutation of Escherichia coli with an Arabidopsis cDNA library, we isolated an Arabidopsis cDNA (At-IE) that possesses these two enzyme activities. The At-IE cDNA encodes a bifunctional protein of 281 amino acids with a calculated molecular mass of 31,666 D. Genomic DNA-blot analysis with the At-IE cDNA as a probe revealed a single-copy gene in Arabidopsis, and RNA-blot analysis showed that the At-IE gene was expressed ubiquitously throughout development. Sequence comparison suggested that the At-IE protein has an N-terminal extension of about 50 amino acids with the properties of a chloroplast transit peptide. We demonstrated through heterologous expression studies in E. coli that the functional domains for the PRA-CH (hisI) and PRA-PH (hisE) resided in the N-terminal and the C-terminal halves, respectively, of the At-IE protein.