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This work presents the measurement of the complex permittivities of high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), polypropylene (PP), Nylon, and thermoplastic vulcanizates (TPV) in irregular shapes at the microwave frequency. A Teflon sample holder was employed to pack irregularly shaped plastic materials with various volumetric percentages. The samples were put into a resonant cavity with an enhanced electric field in its center, which is known as the enhanced-field method (EFM). The resonant frequencies and the quality factors at different volumetric percentages were measured by a network analyzer and compared with simulated results using a full-wave simulator (high-frequency structure simulator (HFSS)). Three simulation models, layer, ring, and hybrid, are proposed and compared with the experimental results. It is found that the hybrid model (denoted as Z5R5) with five heights and five radii in the partition is the most suitable. The complex permittivities of six plastic materials were evaluated by the contour maps of the HFSS simulation using the hybrid model. The measured complex permittivities of the irregularly shaped polymers agree well with their counterparts in bulk form.

Rationale and Objectives This work aimed to study the effects of scanner model and study protocol on radiation dose received by breast tissues from 64-slice computed tomography (CT) studies. Materials and Methods Four scanner models and three study protocols were used in scanning an anthropomorphic phantom with breast modules. Each protocol follows recommendations or guidelines from the American Association of Physicists in Medicine and the American College of Radiology. Twenty thermoluminescent dosimeters were placed inside the breast modules to measure breast tissue doses. Both the absolute and the normalized breast tissue doses were analyzed. Results The mean glandular doses of a lung cancer screening CT, a chest/abdomen/pelvis CT, and a virtual colonoscopy CT are equivalent to less than 1, 5–7, and 1–3 two-view digital mammograms, respectively, for a standard-sized patient. The normalized breast dose differs significantly (P

This work aimed to study the effects of scanner model and study protocol on radiation dose received by breast tissues from 64-slice computed tomography (CT) studies.Four scanner models and three study protocols were used in scanning an anthropomorphic phantom with breast modules. Each protocol follows recommendations or guidelines from the American Association of Physicists in Medicine and the American College of Radiology. Twenty thermoluminescent dosimeters were placed inside the breast modules to measure breast tissue doses. Both the absolute and the normalized breast tissue doses were analyzed.The mean glandular doses of a lung cancer screening CT, a chest/abdomen/pelvis CT, and a virtual colonoscopy CT are equivalent to less than 1, 5-7, and 1-3 two-view digital mammograms, respectively, for a standard-sized patient. The normalized breast dose differs significantly (P 0.01) between lung cancer screening CT and chest/abdomen/pelvis CT; however, it shows less than ±10% variation among scanner models for the same protocol. In virtual colonoscopy CT, breast tissue dose decreases with the distance between local tissues to the edge of the x-ray field, although the decreasing trend varies for different scanner models and protocol settings.When breasts are entirely included in the primary x-ray field, breast dose by 64-slice CT is mainly protocol dependent, with the normalized breast dose about 15% lower for protocols with modulated mA than for those with constant mA; when breasts are only partially included in the primary beam field, breast dose by 64-slice CT is dependent on both the scanner model and the protocol settings.

Objectives: Adults with major depressive disorder (MDD) are reported to have reduced orbitofrontal cortex (OFC) volumes, which could be related to decreased neuronal density. We conducted a study on medication naïve children with MDD to determine whether abnormalities of OFC are present early in the illness course. Methods: Twenty seven medication naïve pediatric Diagnostic and Statistical Manual of Mental Disorders, 4(th) edition (DSM-IV) MDD patients (mean age ± SD = 14.4 ± 2.2 years; 10 males) and 26 healthy controls (mean age ± SD = 14.4 ± 2.4 years; 12 males) underwent a 1.5T magnetic resonance imaging (MRI) with 3D spoiled gradient recalled acquisition. The OFC volumes were compared using analysis of covariance with age, gender, and total brain volume as covariates. Results: There was no significant difference in either total OFC volume or total gray matter OFC volume between MDD patients and healthy controls. Exploratory analysis revealed that patients had unexpectedly larger total right lateral (F = 4.2, df = 1, 48, p = 0.05) and right lateral gray matter (F = 4.6, df = 1, 48, p = 0.04) OFC volumes compared to healthy controls, but this finding was not significant following statistical correction for multiple comparisons. No other OFC subregions showed a significant difference. Conclusions: The lack of OFC volume abnormalities in pediatric MDD patients suggests the abnormalities previously reported for adults may develop later in life as a result of neural cell loss.

Imaging studies indicate smaller orbitofrontal cortex (OFC) volume in mood disorder patients compared with healthy subjects. We sought to determine whether child and adolescent patients with bipolar disorder have smaller OFC volumes than healthy controls. Fourteen children and adolescents meeting DSM-IV criteria for bipolar disorder (six males and eight females with a mean age ± S.D. = 15.5 ± 3.2 years) and 20 healthy controls (11 males and nine females with mean age ± S.D. = 16.9 ± 3.8 years) were studied. Orbitofrontal cortex volume was measured using magnetic resonance imaging. Male bipolar patients had smaller gray matter volumes in medial (p = 0.044), right medial (0.037) and right (p = 0.032) lateral OFC subdivisions compared to male controls. In contrast, female patients had larger gray matter volumes in left (p = 0.03), lateral (p = 0.012), left lateral (p = 0.007), and trends for larger volumes in right lateral and left medial OFC subdivisions compared with female controls. Male patients exhibit smaller gray matter volumes, while female patients exhibit larger volumes in some OFC sub-regions. Gender differences in OFC abnormalities may be involved in illness pathophysiology among young bipolar patients.

There is increasing evidence of a reciprocal fronto-limbic network in the pathogenesis of mood disorders. Prior in vivo proton ((1)H) spectroscopy studies provide evidence of abnormal neurochemical levels in the cingulate and dorsolateral prefrontal cortex (DLPFC) of adult subjects with major depressive disorder (MDD). We examined whether similar abnormalities occur in children and adolescents with MDD. We collected two-dimensional multi-voxel in vivo (1)H spectroscopy data at 1.5 Tesla to quantify levels of N-acetyl-aspartate (NAA), glycerolphosphocholine plus phosphocholine (GPC+PC), and phosphocreatine plus creatine (PCr+Cr) in the DLPFC, medial prefrontal cortex (MPFC), and anterior cingulate (AC) of children and adolescents aged 8-17 years with MDD (n=16) compared with healthy control subjects (n=38). Analysis of covariance with age and gender as covariates was performed. MDD subjects showed significantly lower levels of NAA in the right MPFC and right AC than controls. MDD subjects also had significantly lower levels of GPC+PC in the right AC than control subjects. There were no significant differences in other metabolites in the studied regions. Pediatric patients with MDD exhibit neurochemical alterations in prefrontal cortex regions that are important in the monitoring and regulation of emotional states.

Alcoholism is highly prevalent among bipolar disorder (BD) patients, and its presence is associated with a worse outcome and refractoriness to treatment of the mood disorder. The neurobiological underpinnings that characterize this comorbidity are unknown. We sought to investigate the neurochemical profile of the dorsolateral prefrontal cortex (DLPFC) of BD patients with comorbid alcoholism. A short-TE, single-voxel 1H spectroscopy acquisition at 1.5 Tesla from the left DLFPC of 22 alcoholic BD patients, 26 non-alcoholic BD patients and 54 healthy comparison subjects (HC) were obtained. Absolute levels of N-acetyl aspartate, phosphocreatine plus creatine, choline-containing compounds, myo-inositol, glutamate plus glutamine (Glu+Gln) and glutamate were obtained using the water signal as an internal reference. Analysis of co-variance was used to compare metabolite levels among the three groups. In the primary comparison, non-alcoholic BD patients had higher glutamate concentrations compared to alcoholic BD patients. In secondary comparisons integrating interactions between gender and alcoholism, non-alcoholic BD patients presented significantly higher glutamate plus glutamine (Glu+Gln) than alcoholic BD patients and HC. These results appeared to be driven by differences in male subjects. Alcoholic BD patients with additional drug use disorders presented significantly lower myo-inositol than BD patients with alcoholism alone. The co-occurrence of BD and alcoholism may be characterized by neurochemical abnormalities related to the glutamatergic system and to the inositol second messenger system and/or in glial pathology. These abnormalities may be the neurochemical correlate of an increased risk to develop alcoholism in BD, or of a persistently worse clinical and functional status in BD patients in remission from alcoholism, supporting the clinical recommendation that efforts should be made to prevent or early diagnose and treat alcoholism in BD patients.

The aim of this study was to assess the effectiveness and tolerability of a long-acting methylphenidate (MPH) formulation, beaded MPH (B-MPH), for treatment of attention-deficit/hyperactivity disorder (ADHD) in 4- and 5-year-old children.Eleven children (9 boys and 2 girls) with ADHD received 4 weeks of B-MPH treatment in a single-site, open-label pilot study. Medication dosing was flexible, with titration to a maximum of 30 mg/day. A brief education session on behavior management was offered to parents at each treatment visit.Subjects experienced a mean decrease of 1.09 (standard deviation [SD]=0.73, p0.01) on the Swanson, Nolan, and Pelham Questionnaire (SNAP-IV) ADHD composite score to an end point of 1.18 (SD=0.64). Subjects demonstrated mean decreases in scores of inattention of 1.01 (SD=0.85, p0.01) and in hyperactivity/impulsivity of 1.17 (SD=0.74, p0.01), with end point scores of 1.10 (SD=0.61) and 1.26 (SD=0.77), respectively. The Clinical Global Impressions-Severity (CGI-S) scale showed a statistically significant improvement from a baseline mean of 5 to the final visit mean of 3.36 (p0.01). At the final visit, the mean daily B-MPH dose was 17.73 mg. Subjects did not experience any statistically significant changes in weight, blood pressure, or pulse during the study. The most common adverse event was decreased appetite.B-MPH was safe and effective for the treatment of ADHD in the 4- and 5-year-olds participating in this study.

The dorsolateral prefrontal cortex (DLPFC) has been implicated in the pathophysiology of mental disorders. Previous region-of-interest MRI studies that attempted to delineate this region adopted various landmarks and measurement techniques, with inconsistent results. We developed a new region-of-interest measurement method to obtain morphometric data of this region from structural MRI scans, taking into account knowledge from cytoarchitectonic postmortem studies and the large inter-individual variability of this region. MRI scans of 10 subjects were obtained, and DLPFC tracing was performed in the coronal plane by two independent raters using the semi-automated software Brains2. The intra-class correlation coefficients between two independent raters were 0.94 for the left DLPFC and 0.93 for the right DLPFC. The mean +/- S.D. DLPFC volumes were 9.23 +/- 2.35 ml for the left hemisphere and 8.20 +/- 2.08 ml for the right hemisphere. Our proposed method has high inter-rater reliability and is easy to implement, permitting the standardized measurement of this region for clinical research applications