1,926 research outputs found
Plasma deposition of constrained layer damping coatings
Plasma techniques are used to generate constrained layer damping (CLD) coatings on metallic substrates. The process involves the deposition of relatively thick, hard ceramic layers on to soft polymeric damping materials while maintaining the integrity of both layers. Reactive plasma sputter-deposition from an aluminium alloy target is used to deposit alumina layers, with Young's modulus in the range 77-220GPa and thickness up to 335 μ, on top of a silicone film. This methodology is also used to deposit a 40 μ alumina layer on a conventional viscoelastic damping film to produce an integral damping coating. Plasma CLD systems are shown to give at least 50 per cent more damping than equivalent metal-foil-based treatments. Numerical methods for rapid prediction of the performance of such coatings are discussed and validated by comparison with experimental results
Genomic Analysis of Advanced Breast Cancer Using Two Types of Next Generation Sequencing
The aim of this study is to characterize the genomic alterations of advance stage breast cancer using next generation sequencing (NGS) to identify pathways that may be commonly altered in advance stage breast cancer
LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association
<p>Abstract</p> <p>Background</p> <p>In patients with severe aortic stenosis (AS), long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR) offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability.</p> <p>Hypothesis</p> <p>We hypothesize that changes in LV structure and function following aortic valve replacement (AVR) are detectable by CMR and once triggered by AVR, continue for an extended period.</p> <p>Methods</p> <p>Tweny-four patients of which ten (67 ± 12 years, 6 female) with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured.</p> <p>Results</p> <p>All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m<sup><b>2</b></sup>, p < 0.005) and continued trending downwards through 4 years (127 ± 32 g/m<sup><b>2</b></sup>). Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p < 0.05)) and continued trending upwards, remaining stable through years 1-4 (66 ± 11 vs. 65 ± 9%). LVEDVI, initially high pre-AVR, decreased post-AVR (83 ± 30 to 68 ± 11 ml/m2, p < 0.05) trending even lower by year 4 (66 ± 10 ml/m<sup><b>2</b></sup>). LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p < 0.05) continuing to increase non-significantly through 4 years (49 ± 14 ml) with these LV metrics paralleling improvements in NYHA. However, LVmass/volume, a 3D measure of LV geometry, remained unchanged over 4 years.</p> <p>Conclusion</p> <p>After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.</p
How Prevalent Are Autistic Traits Among Children With Attention-Deficit/Hyperactivity Disorder? A Qualitative Review of the Literature
Twin, family, and linkage studies have indicated that attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASDs) share a portion of their heritable etiology. This suggests that individuals with ADHD may manifest different forms of ASDs that may range from fully developed syndromic forms of the disorder to milder manifestations of ASD symptomatology, which will henceforth be referred to as autistic traits.The main purpose of this study was to conduct a literature search to examine the current body of knowledge regarding the prevalence of autistic traits (operationalized as the presence of autistic symptoms in the absence of a diagnosis of ASD) among children with ADHD and the associated morbidity of such traits.A systematic literature search in PubMed was conducted to discover all controlled studies published in the English language that systematically assessed the presence of autistic traits in children with ADHD who did not meet the criteria for ASDs. Three articles met our inclusion and exclusion criteria and were included in this qualitative review.Only three scientific papers that met our a priori inclusion and exclusion criteria were identified. These articles described findings obtained from clinical samples and identified a prevalence of autistic traits among children with ADHD that ranged from 7% to 60%. As compared with children with ADHD without these traits, the presence of autistic traits in children with ADHD was associated with more severe dysfunction in a wide range of non-overlapping domains and in the social and communication domains in particular.Although this study was limited by the small amount of available literature about this subject, these findings suggest that a sizeable subset of children with ADHD manifest autistic traits and that the presence of these traits is associated with increased dysfunction and social and communication deficits
Economic burden and comorbidities of attention-deficit/hyperactivity disorder among pediatric patients hospitalized in the United States
<p>Abstract</p> <p>Background</p> <p>This retrospective database analysis used data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample (NIS) to examine common primary diagnoses among children and adolescents hospitalized with a secondary diagnosis of attention- deficit/hyperactivity disorder (ADHD) and assessed the burden of ADHD.</p> <p>Methods</p> <p>Hospitalized children (aged 6-11 years) and adolescents (aged 12-17 years) with a secondary diagnosis of ADHD were identified. The 10 most common primary diagnoses (using the first 3 digits of the ICD-9-CM code) were reported for each age group. Patients with 1 of these conditions were selected to analyze demographics, length of stay (LOS), and costs. Control patients were selected if they had 1 of the 10 primary diagnoses and no secondary ADHD diagnosis. Patient and hospital characteristics were reported by cohort (i.e., patients with ADHD vs. controls), and LOS and costs were reported by primary diagnosis. Multivariable linear regression analyses were undertaken to adjust LOS and costs based on patient and hospital characteristics.</p> <p>Results</p> <p>A total of 126,056 children and 204,176 adolescents were identified as having a secondary diagnosis of ADHD. Among children and adolescents with ADHD, the most common diagnoses tended to be mental health related (i.e., affective psychoses, emotional disturbances, conduct disturbances, depressive disorder, or adjustment reaction). Other common diagnoses included general symptoms, asthma (in children only), and acute appendicitis. Among patients with ADHD, a higher percentage were male, white, and covered by Medicaid. LOS and costs were higher among children with ADHD and a primary diagnosis of affective psychoses (by 0.61 days and 940), or depressive disorder (by 0.41 days and 352), depressive disorder (by 0.94 days and 1,330), emotional disturbances (by 1.45 days and 702), and neurotic disorders (by 1.60 days and $541) versus controls.</p> <p>Conclusion</p> <p>Clinicians and health care decision makers should be aware of the potential impact of ADHD on hospitalized children and adolescents.</p
Are Autistic Traits in Youth Meaningful? A Replication study in Non-referred Siblings of Youth with and without Attention-Deficit/Hyperactivity Disorder
Background: We previously described the high prevalence and burden of significant autistic traits (ATs) in youth with attention-deficit/hyperactivity disorder (ADHD). These traits are associated with significantly greater impairment in psychopathological, interpersonal, educational, and neuropsychological functioning. Because the sample consisted of referred ADHD youth, uncertainty remained regarding whether these findings are generalizable to non-referred populations of youths with and without ADHD.
Objective: The aim of the current study was to assess the prevalence and implications of ATs in a non-referred population of siblings of probands with and without ADHD.
Method: Participants were non-referred siblings of probands with ADHD (N = 257) and control probands (N = 234) of longitudinal, case-control family studies conducted at Massachusetts General Hospital. Assessments included measures of psychiatric, psychosocial, educational, and cognitive functioning. The presence of significant ATs was operationalized using the Child Behavior Checklist AT profile, which consists of combined aggregate T-scores of ≥ 195 on the Withdrawn, Social, and Thought Problems subscales.
Results: ATs were significantly more prevalent among the siblings of probands with ADHD as compared with siblings of control probands (6% vs. 1%; P = .02). Siblings of probands with ADHD with a positive AT profile (N = 15) were significantly more impaired than those without an AT profile (N = 242) with regard to psychopathological, interpersonal, educational, and neuropsychological functioning.
Conclusions: The current study reports a higher-than-expected prevalence of ATs in a non-referred sample of siblings of youth with ADHD, which is consistent with previous findings regarding ATs in a referred sample of youth with ADHD. The presence of ATs is associated with higher levels of morbidity and dysfunction
More salt, please:global patterns, responses, and impacts of foliar sodium in grasslands
Sodium is unique among abundant elemental nutrients, because most plant species do not require it for growth or development, whereas animals physiologically require sodium. Foliar sodium influences consumption rates by animals and can structure herbivores across landscapes. We quantified foliar sodium in 201 locally abundant, herbaceous species representing 32 families and, at 26 sites on four continents, experimentally manipulated vertebrate herbivores and elemental nutrients to determine their effect on foliar sodium. Foliar sodium varied taxonomically and geographically, spanning five orders of magnitude. Site‐level foliar sodium increased most strongly with site aridity and soil sodium; nutrient addition weakened the relationship between aridity and mean foliar sodium. Within sites, high sodium plants declined in abundance with fertilisation, whereas low sodium plants increased. Herbivory provided an explanation: herbivores selectively reduced high nutrient, high sodium plants. Thus, interactions among climate, nutrients and the resulting nutritional value for herbivores determine foliar sodium biogeography in herbaceous‐dominated systems
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