Fatigue Response of Cracked Aluminum Panel with Partially Bonded Composite Patch

More and more aircraft, both commercial and military, are being called upon to fly well beyond their economic and structural service lives. Budget cuts and dwindling new aircraft development has forced the United States Air Force (USAF) to look toward more reliable structural repairs. One of these repair techniques, which was the subject of this study, is the repair of metallic aircraft structures using high strength composite materials. This study investigated the fatigue response of a precracked, 508x1 52x1 mm, 2024-T3 aluminum panel repaired with a partially bonded, unidirectional, three-ply boron/epoxy composite reinforcement with ply lengths of 68, 56 and 50 mm and a width of 50 mm. Intentional disbonds were created in the bondline of the repair using teflon inserts to simulate defects seen in real applications due to service conditions or during manufacturing. The repaired panels were subjected to constant amplitude fatigue testing at a peak load of 120 MPa to study the damage and fatigue tolerance of partially bonded composite reinforcements to cracked aluminum panels. The effects of various disbond locations and sizes were investigated and compared to each other as well as to panels repaired with a completely bonded reinforcement and to cracked panels without any reinforcement. Five disbond locations were investigated. Also, the effect of disbond size varying from 5 to 20% of the total bond area for a few cases of disbond location was investigated. It was found that disbonds around the crack resulted in greater crack growth rates and reduced specimen life. The amount of patch efficiency reduction was a function of how much of the crack was covered by the disbond during growth within the patch as well as the size of the disbond perpendicular to the crack

Is the Concept of Quality of Life Relevant for Multiple Sclerosis Patients with Cognitive Impairment? Preliminary Results of a Cross-Sectional Study

Background: Cognitive impairment occurs in about 50 % of multiple sclerosis (MS) patients, and the use of self-reported outcomes for evaluating treatment and managing care among subjects with cognitive dysfunction has been questioned. The aim of this study was to provide new evidence about the suitability of self-reported outcomes for use in this specific population by exploring the internal structure, reliability and external validity of a specific quality of life (QoL) instrument, the Multiple Sclerosis International Quality of Life questionnaire (MusiQoL). Methods: Design: cross-sectional study. Inclusion criteria: MS patients of any disease subtype. Data collection: sociodemographic (age, gender, marital status, education level, and occupational activity) and clinical data (MS subtype, Expanded Disability Status Scale, disease duration); QoL (MusiQoL and SF36); and neuropsychological performance (Stroop color-word test). Statistical analysis: confirmatory factor analysis, item-dimension correlations, Cronbach’s alpha coefficients, Rasch statistics, relationships between MusiQoL dimensions and other parameters. Principal Findings: One hundred and twenty-four consecutive patients were enrolled. QoL scores did not differ between the 69 cognitively non-impaired patients and the 55 cognitively impaired patients, except for the symptoms dimension. The confirmatory factor analysis performed among the impaired subjects showed that the structure of the questionnaire matched with the initial structure of the MusiQoL. The unidimensionality of the MusiQoL dimensions was preserved, and th

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Systemic Mastocytosis Presenting as Acute Appendicitis: A Case Report and Review of the Literature

Systemic mastocytosis is characterized by abnormal growth and accumulation of mast cells in various organs. Gastrointestinal (GI) symptoms are common disease manifestations in this disease and can significantly impair the quality of life. Signs of GI systemic mastocytosis include steatorrhea, malabsorption, hepatomegaly, splenomegaly, portal hypertension, and ascites. Acute appendicitis as a presenting feature in systemic mastocytosis has not been reported in the literature previously. In this report, we discuss the case of a female patient with systemic mastocytosis (c-KIT D816V (+)) who was admitted for right-sided acute abdominal pain. Laboratory study revealed an normal white blood cell count with eosinophilia and an elevated serum tryptase level of 23 μg/l. CT of the abdomen and pelvis showed an enlarged appendix of 12 mm in diameter, with minimal wall enhancement. Laparoscopic appendectomy was performed. The appendix was found to be hyperemic and firm, and it was densely adherent to the posterior cecum, the surrounding peritoneal wall, and the overlying mesenteric fat. Pathology revealed acute appendicitis with greater than 30 mast cells per high-power field by immunoperoxidase studies with mast cell tryptase and CD117. The patient subsequently improved and was discharged home. This case is the first reported case with a histological diagnosis of acute appendicitis resulting from mast cell infiltration. Physicians should be aware of acute appendicitis as a manifestation of systemic mastocytosis. Prompt diagnosis and management may prevent potentially fatal complications of appendiceal perforation and peritonitis

Defining and Assessing Wisdom: A Review of the Literature

With increasing longevity and a growing focus on successful aging, there has been a recent growth of research designed to operationalize and assess wisdom. We aimed to (1) investigate the degree of overlap among empirical definitions of wisdom, (2) identify the most commonly cited wisdom subcomponents, (3) examine the psychometric properties of existing assessment instruments, and (4) investigate whether certain assessment procedures work particularly well in tapping the essence of subcomponents of the various empirical definitions. We searched PsychINFO-indexed articles published through May 2012 and their bibliographies. Studies were included if they were published in a peer-reviewed journal and (1) proposed a definition of wisdom or (2) discussed the development or validation of an instrument designed to assess wisdom. Thirty-one articles met inclusion criteria. Despite variability among the 24 reviewed definitions, there was significant overlap. Commonly cited subcomponents of wisdom included knowledge of life, prosocial values, self-understanding, acknowledgement of uncertainty, emotional homeostasis, tolerance, openness, spirituality, and sense of humor. Published reports describing the psychometric properties of nine instruments varied in comprehensiveness but most measures were examined for selected types of reliability and validity, which were generally acceptable. Given limitations of self-report procedures, an approach integrating multiple indices (e.g., self-report and performance-based measures) may better capture wisdom. Significant progress in the empirical study of wisdom has occurred over the past four decades; however, much needs to be done. Future studies with larger, more diverse samples are needed to determine the generalizability, usefulness, and clinical applicability of these definitions and assessment instruments. Such work will have relevance for the fields of geriatrics, psychiatry, psychology, sociology, education, and public health, among others