bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic deformation characteristics of porcine aortic valve leaflet under normal and hypertensive conditions
Authors: Yap Choon Hwai , Kim Hee-Sun , Balachandran Kartik , Weiler Michael , Haj-Ali Rami , Yoganathan Ajit P.
Published: November 2009

Calcific aortic valve (AV) disease has a high prevalence in the United States, and hypertension is correlated to early onset of the disease. The cause of the disease is poorly understood, although biological and remodeling responses to mechanical forces, such as membrane tension, have been hypothesized to play a role. The mechanical behavior of the native AV has, therefore, been the focus of many recent studies. In the present study, the dynamic deformation characteristics of the AV leaflet and the effects of hypertension on leaflet deformation are quantified. Whole porcine aortic roots were trimmed and mounted in an in vitro pulsatile flow loop and subjected to normal (80/120 mmHg), hypertensive (120/160 mmHg), or severe hypertensive (150/190 mmHg) conditions. Local valve leaflet deformations were calculated with dual-camera photogrammetry method: by tracking the motion of markers placed on the AV leaflets in three dimensions and calculating their spatial deformations. The results demonstrate that, first, during diastole, high transvalvular pressure induces a stretch waveform which plateaus over the diastolic duration in both circumferential and radial directions. During systole, the leaflet stretches in the radial direction due to forward flow drag forces but compresses in the circumferential direction in a manner in agreement with Poisson's effect. Second, average diastolic and systolic stretch ratios were quantified in the radial and circumferential directions in the base and belly region of the leaflet, and diastolic stretch was found to increase with increasing pressure conditions.
Regulation of the ADMA-DDAH system in endothelial cells: a novel mechanism for the sterol response element binding proteins, SREBP1c and -2
Authors: Ivashchenko Christine Y. , Bradley Benjamin T. , Ao Zhaohui , Leiper James , Vallance Patrick , Johns Douglas G.
Published: November 2009

Asymmetric dimethylarginine (ADMA) has been implicated in the progression of cardiovascular disease as an endogenous inhibitor of nitric oxide synthase. The regulation of dimethylarginine dimethylaminohydrolase (DDAH), the enzyme responsible for metabolizing ADMA, is poorly understood. The transcription factor sterol response element binding protein (SREBP) is activated by statins via a reduction of membrane cholesterol content. Because the promoters of both DDAH1 and DDAH2 isoforms contain sterol response elements, we tested the hypothesis that simvastatin regulates DDAH1 and DDAH2 transcription via SREBP. In cultured endothelial cells, simvastatin increased DDAH1 mRNA expression compared with vehicle. In an ADMA loading experiment, simvastatin treatment resulted in a decrease in ADMA content, an indication of increased DDAH activity. The knockdown of SREBP1c protein led to an increase in DDAH1 mRNA expression and activity, whereas the knockdown of SREBP2 led to a decrease in DDAH1 mRNA expression. The role of SREBP2 in the activation of the DDAH1 was supported by chromatin immunoprecipitation studies demonstrating increased binding of SREBP2 to the DDAH1 promoter upon simvastatin stimulation. These data indicate that SREBP1c might act as a repressor and SREBP2 as an activator of DDAH transcription and activity. This study describes a novel mechanism of reciprocal regulation by the SREBP family members of the DDAH-ADMA system, which represents a potential link between cellular cholesterol content and endothelial dysfunction observed in cardiovascular disease.
Long-term maternal cardiovascular function in a mouse model of sFlt-1-induced preeclampsia
Authors: Bytautiene Egle , Lu Fangxian , Tamayo Esther H. , Hankins Gary D. V. , Longo Monica , Kublickiene Karolina , Saade George R.
Published: November 2009

Our aim was to evaluate the long-term effects of preeclampsia on vascular function in a mouse model induced by sFlt-1 overexpression. CD-1 mice at day 8 of gestation were injected via the tail vein with adenovirus carrying sFlt1 (AdsFlt1), adenovirus carrying the murine IgG2α Fc fragment as the adenovirus control (AdmFc), or saline. Vascular function in the mothers was investigated 6–8 mo after delivery by recording blood pressure (BP) by telemetry (AdsFlt1 n = 8, AdmFc n = 6, saline n = 4) and exploring carotid artery reactivity in a wire myograph (AdsFlt1 n = 6, AdmFc n = 8, saline n = 4). sFlt-1 blood levels at 6–8 mo postpartum had returned to low levels and were comparable between the three groups ( P = 0.808). There was no statistically significant difference in BP ( P = 0.067) or vascular reactivity between the three groups of postpartum mice (phenylephrine P = 0.079, thromboxane P = 0.979, serotonin P = 0.659, acetylcholine P = 0.795, sodium nitroprusside P = 0.728, isoproterenol P = 0.370). Our results indicate that in a mouse model overexpression of sFlt-1 does not lead to increased in BP and altered vascular function in the absence of the pregnancy and has no long-term effect on BP and vascular function in the postpartum mothers. Our findings favor the hypothesis that increased cardiovascular diseases in women with history of preeclampsia are likely the result of preexisting risk factors common to preeclampsia and cardiovascular diseases.
Remodeling of skeletal muscle microvasculature in sickle cell trait and α-thalassemia
Authors: Vincent Lucile , Féasson Léonard , Oyono-Enguéllé Samuel , Banimbek Viviane , Denis Christian , Guarneri Catherine , Aufradet Emeline , Monchanin Géraldine , Martin Cyril , Gozal David , Dohbobga Macias , Wouassi Dieudonné , Garet Martin , Thiriet Patrice , Messonnier Laurent
Published: November 2009

The influence of sickle cell trait and/or α-thalassemia on skeletal muscle microvascular network characteristics was assessed and compared with control subjects [hemoglobin (Hb) AA] in 30 Cameroonian residents [10 HbAA, 5 HbAA α-thalassemia (α-t), 6 HbAS, and 9 HbASα-t] matched for maximal work capacity and daily energy expenditure. Subjects performed an incremental exercise to exhaustion and underwent a muscle biopsy. Muscle fiber type and surface area were not different among groups. However, sickle cell trait (SCT) was associated with lower capillary density ( P < 0.05), lower capillary tortuosity ( P < 0.001), and enlarged microvessels ( P < 0.01). SCT carriers had reduced counts of microvessels <5-μm diameter, but a higher percentage of broader microvessels, i.e., diameter >10 μm ( P < 0.05). α-Thalassemia seemed to be characterized by a higher capillary tortuosity and unchanged capillary density and diameter. Thus, while SCT is a priori clinically benign, we demonstrate for the first time that significant remodeling of the microvasculature occurs in SCT carriers. These modifications may possibly reflect protective adaptations against hemorheological and microcirculatory dysfunction induced by the presence of HbS. The remodeling of the microvascular network occurs to a lesser extent in α-thalassemia. In α-thalassemic subjects, increased capillary tortuosity would promote oxygen supply to muscle tissues and might compensate for the lower Hb content often reported in those subjects.
Effects of aerobic exercise training on sympathetic and renal responses to mental stress in humans
Authors: Ray Chester A. , Carter Jason R.
Published: November 2009

The effects of aerobic exercise training (ET) on muscle sympathetic nerve activity (MSNA) and renal vascular responses to mental stress (MS) have not been determined in humans. We hypothesized that aerobic ET would reduce MSNA and renal vasoconstriction during MS. MSNA, mean arterial pressure (MAP), heart rate, renal blood flow velocity (RBFV), and peak oxygen uptake (V̇o2 peak) were recorded in 23 healthy adults. Fourteen subjects participated in 8 wk of aerobic ET, while nine subjects served as sedentary controls (Con). ET significantly increased V̇o2 peak (Δ18 ± 1%; P < 0.001) and decreased RBFV at rest (60 ± 4 to 48 ± 3 cm/s; P < 0.01), whereas Con did not alter V̇o2 peak or RBFV. ET did not alter resting MSNA (11 ± 1 to 9 ± 1 bursts/min) or MAP (84 ± 2 to 83 ± 2 mmHg), and these findings were similar in the Con group. MS elicited similar increases in MSNA (∼Δ2 bursts/min; P < 0.05), MAP (∼Δ15 mmHg; P < 0.001), and heart rate (∼Δ20 beats/min; P < 0.001) before and after ET, and the responses were not different between ET and Con. Likewise, MS elicited similar decreases in RBFV and renal vascular conductance before and after ET, and the responses were not different between ET and Con. Perceived stress levels during MS were similar before and after the 8-wk study in both ET and Con. In conclusion, ET does not alter MSNA and renal vascular responses to MS in healthy humans.
High-resolution electrical mapping of depolarization and repolarization alternans in an ischemic dog model
Authors: Gordon David , Kadish Alan H. , Koolish Daniel , Taneja Taresh , Ulphani Joseph , Goldberger Jeffrey J. , Ng Jason
Published: November 2009

Cardiac electrical alternans have been associated with spontaneous ventricular arrhythmias during myocardial ischemia. The study aims were to use a new algorithm to measure depolarization and repolarization alternans from epicardial electrograms in an ischemia model and to evaluate which features are predictive of ventricular fibrillation (VF). The left anterior descending coronary artery was occluded in 21 dogs, of which 6 developed spontaneous VF. Four seconds of unipolar epicardial electrograms was recorded before and 5 min after occlusion from an 8 × 14-electrode plaque placed on the anterior left ventricle. Alternans amplitudes were estimated with a triangular wave-fitting algorithm and for each unipolar electrogram for various measurements of the QRS and ST-T wave amplitude. The root mean square error was computed for each fit. Receiver-operator characteristic curves were used to determine whether prevalence of alternans having estimated alternans amplitude-to-error ratio (A/E) above a given threshold could distinguish the dogs who had and did not have spontaneous VF. The prevalence of alternans after ischemia was highly predictive of VF when measured both during depolarization (sensitivity of 83% and specificity of 87%) and during repolarization (sensitivity of 100% and specificity of 73%). The optimal alternans A/E ranged from 1 to 4. There were no differences in the level of discordance or alternans amplitude between dogs who developed VF versus dogs who did not. The prevalence of alternans in the ventricles may be the key risk factor for developing VF during myocardial ischemia when short-term recordings are used.
Characterization of the PcCdc42 small G protein from Pneumocystis carinii, which interacts with the PcSte20 life cycle regulatory kinase
Authors: Krajicek Bryan J. , Kottom Theodore J. , Villegas Leah , Limper Andrew H.
Published: November 2009

Pneumocystis carinii (Pc) causes severe pneumonia in immunocompromised hosts. The binding of Pc trophic forms to alveolar epithelial cells is a central feature of infection, inducing the expression and activation of PcSte20, a gene participating in mating, proliferation, and pseudohyphal growth. In related fungi, Ste20 proteins are generally activated by immediate upstream small G proteins of the Cdc42-like family. PcCdc42 has not been previously described in Pneumocystis . To address the potential role of such a G protein in Pneumocystis , PcCdc42 was cloned from a Pc cDNA library. Using the full-length 576-bp PcCdc42 cDNA sequence, a CHEF blot of genomic DNA yielded a single band, providing evidence that this gene is present as a single copy within the genome. The total length of PcCdc42 cDNA was 576 bp with an estimated molecular mass of ∼38 kDa. BLASTP analysis demonstrated greater than 80% homology with other fungal Cdc42p proteins. Northern analysis indicated equal mRNA expression in both cystic and trophic life forms. Heterologous expression of PcCdc42 in Saccharomyces cerevisiae (Sc) demonstrated that PcCdc42p was able to restore growth in an ScCdc42Δ yeast strain. Additional assays with purified PcCdc42 protein demonstrated GTP binding and intrinsic GTPase activity, which was partially but significantly suppressed by Clostridium difficile toxin B, characteristic of Cdc42 GTPases. Furthermore, PcCdc42 protein was also shown to bind to the downstream PCSte20 kinase partner in the presence (but not the absence) of GTP. These data indicate that Pc possesses a Cdc42 gene expressing an active G protein, which binds the downstream regulatory kinase PcSte20, important in Pc life cycle regulation.
Role of hypoxia-inducible factor 1α in modulating cobalt-induced lung inflammation
Authors: Saini Yogesh , Kim Kyung Y. , Lewandowski Ryan , Bramble Lori A. , Harkema Jack R. , LaPres John J.
Published: November 2009

Hypoxia plays an important role in development, cellular homeostasis, and pathological conditions, such as cancer and stroke. There is also growing evidence that hypoxia is an important modulator of the inflammatory process. Hypoxia-inducible factors (HIFs) are a family of proteins that regulate the cellular response to oxygen deficit, and loss of HIFs impairs inflammatory cell function. There is little known, however, about the role of epithelial-derived HIF signaling in modulating inflammation. Cobalt is capable of eliciting an allergic response and promoting HIF signaling. To characterize the inflammatory function of epithelial-derived HIF in response to inhaled cobalt, a conditional lung-specific HIF1α, the most ubiquitously expressed HIF, deletion mouse, was created. Control mice showed classic signs of metal-induced injury following cobalt exposure, including fibrosis and neutrophil infiltration. In contrast, HIF1α-deficient mice displayed a Th2 response that resembled asthma, including increased eosinophilic infiltration, mucus cell metaplasia, and chitinase-like protein expression. The results suggest that epithelial-derived HIF signaling has a critical role in establishing a tissue's inflammatory response, and compromised HIF1α signaling biases the tissue towards a Th2-mediated reaction.
Effects of secretagogues on net and unidirectional liquid fluxes across porcine bronchial airways
Authors: Martens Chelsea J. , Ballard Stephen T.
Published: November 2009

Rates of liquid secretion and absorption across the bronchopulmonary airways are important for regulating airway surface liquid volume and maintaining mucociliary transport. The current study demonstrates the feasibility of measuring not just net liquid movements but unidirectional liquid movements across isolated intact bronchi from swine. Airways were liquid filled to assess both net liquid movements, and, in the presence of NPPB to selectively inhibit secretion, unidirectional absorption. Unidirectional liquid secretion rates were determined by subtraction. For comparison, net liquid movements were assessed in air-filled airways in parallel. In the absence of secretagogues, unidirectional absorption was observed (4.63 ± 0.53 μl·cm−2·h−1) with little unidirectional secretion (1.42 ± 0.36 μl·cm−2·h−1). ACh, substance P (SP), and vasoactive intestinal peptide (VIP) all induced unidirectional secretion (10.64 ± 1.52 μl·cm−2·h−1, 14.16 ± 1.39 μl·cm−2·h−1, and 4.25 ± 0.25 μl·cm−2·h−1, respectively) without affecting unidirectional absorption. Net liquid secretion in air-filled airways was close to that in liquid-filled airways except with VIP. VIP induced net secretion in air-filled airways (4.44 ± 1.26 μl·cm−2·h−1), but negligible net change in liquid movement occurred in liquid-filled airways. This effect was likely to have been caused by the higher solid content of the VIP-induced mucous liquid (3.98 ± 0.26%) compared with the ACh- and SP-induced liquid (2.06 ± 0.07% and 2.15 ± 0.07%, respectively). We conclude that this technique allows important quantitative distinctions to be made between liquid secretion and absorption in intact bronchial airways.
Publishing flow cytometry data
Authors: Alvarez D. F. , Helm K. , DeGregori J. , Roederer M. , Majka S.
Published: November 2009

Cellular measurements by flow cytometric analysis constitute an important step toward understanding individual attributes within a population of cells. Assessing individual cells within a population by protein expression using fluorescently labeled antibodies and other fluorescent probes can identify cellular patterns. The technology for accurately identifying subtle changes in protein expression within a population of cells using a vast array of technology has resulted in controversy and questions regarding reproducibility, which can be explained at least in part by the absence of standard methods to facilitate comparison of flow cytometric data. The complexity of technological advancements and the need for improvements in biological resolution results in the generation of complex data that demands the use of minimum standards for their publication. Herein we present a summarized view for the inclusion of consistent flow cytometric experimental information as supplemental data. Four major points, experimental and sample information, data acquisition, analysis, and presentation are emphasized. Together, these guidelines will facilitate the review and publication of flow cytometry data that provide an accurate foundation for ongoing studies with this evolving technology.
Selected Nonmusic Predictors of Urban Students’ Decisions to Enroll and Persist in Middle School Band Programs
Authors: Kinney Daryl W.
Published: November 2009

The purpose of this study was to fit theoretical models of prediction to students’ decisions to enroll and persist in urban middle school band programs using independent variables of academic achievement, socioeconomic status (SES), family structure, mobility, ethnicity, and gender. Two models were fitted to the data using logistic regression analysis techniques. One predicted initial enrollment (i.e., sixth grade); the other predicted retention (i.e., eighth grade). Academic achievement and family structure emerged as the only significant predictors of initial enrollment decisions. Higher academically achieving students and those from two-parent or two-guardian homes were more likely to begin band instruction. Higher academically achieving students and those from two-parent or two-guardian homes also were more likely to persist in band, as were students from higher SES and females. Comparisons between models suggest slight differences in the nonmusic factors affecting initial enrollment and retention.
Effects of Familiarity With a Melody Prior to Instruction on Children’s Piano Performance Accuracy
Authors: Goins Frewen Katherine
Published: November 2009

The main purpose of this study was to examine the effects of familiarity with the sound of a melody on children’s performance of the melody. Children in kindergarten through fourth grade ( N = 97) with no previous formal instrumental instruction were taught to play a four-measure melody on a keyboard during an individual instruction session. Before learning to play the melody, half of the children listened to a model of the melody repeatedly in music class to become familiar with the music. Children’s familiarity with the melody was assessed through a melodic error identification test administered immediately before and after instruction. The results indicated that children who were familiar with the melody played significantly more correct notes than did children not familiar with the melody and that performance accuracy increased with grade level.
Community-Based Summer Work Experiences of Adolescents With High-Incidence Disabilities
Authors: Carter Erik W. , Trainor Audrey A. , Ditchman Nicole , Swedeen Beth , Owens Laura
Published: November 2009

Although summer offers a natural context for adolescents to gain community-based work experience, little is known about the extent to which youth with disabilities are accessing these transition-related opportunities. We examined the summer employment experiences of 220 youth with high-incidence disabilities at two time points. Although more than half of all youth were employed at some point during the summer, youth with emotional/behavioral disorders and intellectual disabilities worked at significantly lower rates than youth with learning disabilities, and all received limited formal support related to finding and maintaining their jobs. Skill-related factors and spring work experience emerged as prominent predictors of summer employment outcomes. We present recommendations for schools, families, and communities to expand summer employment opportunities for youth with disabilities as an avenue for promoting career development.
Walking the Walk: Teacher Candidates’ Professed Commitment to Urban Teaching and Their Subsequent Career Decisions
Authors: Frankenberg Erica , Taylor Amanda , Merseth Katherine
Published: November 2009

This study is a longitudinal analysis of the early career decisions made by graduates of an urban-focused secondary teacher preparation program. By matching graduates’ self-reported commitment to teaching in urban schools at the end of the training program to the demographic data of the schools where they subsequently teach, the authors explore the relationship between preservice teacher attitudes about urban schools and their actual career decisions by tracking the urbanicity and student characteristics of graduates’ schools. The authors find that most graduates attain teaching jobs in urban schools, and higher percentages of graduates who exit the program more committed to teaching in urban schools take jobs in urban schools with higher percentages of students of color and low-income students. The vast majority of graduates remain in urban schools, but those graduates who transfer to work in less urban and/or schools with fewer students of color or teachers who leave the field altogether are those who reported lower urban commitment. Understanding how professed commitments to teaching in urban schools at the end of a teacher education program are associated with the subsequent career decisions of graduates represents an important step in understanding why some individuals elect to teach and remain in urban schools.
Pharmacokinetics of Loxapine Following Inhalation of a Thermally Generated Aerosol in Healthy Volunteers
Authors: Spyker Daniel A. , Munzar Patrik , Cassella James V.
Published: November 2009

The objective of this randomized, double‐blind, placebo‐controlled, dose escalation study was to determine the pharmacokinetic characteristics, safety, and tolerability of single doses of inhaled loxapine aerosol in healthy volunteers. Loxapine was delivered by means of a unique thermally generated aerosol comprising drug particles of a size designed for deep lung delivery and absorption. Fifty participants were randomized to receive 0.625, 1.25, 2.5, 5.0, or 10 mg of loxapine aerosol or placebo. Following inhalation, the tmax median (25%, 75%) was 2 (1, 3) minutes. The loxapine AUC∞ was dose proportional across all doses with slope (90% confidence interval) of log AUC∞ versus log dose = 0.909 (0.832, 0.987). No clinically meaningful changes were noted in hematology results, blood chemistry, vital signs, or respiratory function. The most common adverse events were dizziness, somnolence, and bad taste. The inhalation of Staccato loxapine represents a safe, well‐tolerated means for rapidly achieving therapeutic plasma concentrations of loxapine.
Sheltering the Self From the Storm: Self-Construal Abstractness and the Stability of Self-Esteem
Authors: Updegraff John A. , Emanuel Amber S. , Suh Eunkook M. , Gallagher Kristel M.
Published: November 2009

Self-construal abstractness (SCA) refers to the degree to which people construe important bases of self-esteem in a broad, flexible, and abstract rather than a concrete and specific manner. This article hypothesized that SCA would be a unique predictor of self-esteem stability, capturing the degree to which people’s most important bases of self-worth are resistant to disconfirmation. Two studies using a daily diary methodology examined relationships between SCA, daily self-esteem, and daily emotions and/or events. In Study 1, individual differences in SCA emerged as the most consistent and unique predictor of self-esteem stability. Furthermore, SCA contributed to self-esteem stability by buffering the influence of daily negative emotions on self-esteem. Study 2 manipulated SCA via a daily self-construal task and found an abstract versus concrete self-focus to buffer the influence of daily negative events on self-esteem. Implications of these findings for the study of the self and well-being are discussed.
Impact of Role Discrepancies on Caregiver Burden Among Spouses
Authors: Savundranayagam Marie Y. , Montgomery Rhonda J. V.
Published: November 2009

Using caregiver identity theory, the authors investigated whether role discrepancies mediated the relationships between illness-related stressors (activities of daily living [ADLs] limitations and problem behaviors) and burden (stress, relationship, and objective burden) for spouse caregivers. Participants completed measures of identity standards for spouse and caregiver roles and behaviors, burden, assistance with ADLs, and problem behaviors. Structural equation modeling analyses revealed that role discrepancies completely mediated the relationships between ADLs and stress and relationship burden. Although role discrepancies mediated the relationships between problem behaviors and all forms of burden, there were direct relationships between problem behaviors and burden. Finally, participants who exceeded their relationship identity standards experienced greater burden. Supporting caregiver identity theory, the results suggest that ADL assistance is burdensome for caregivers when it highlights inconsistencies between their behaviors and their relationship expectations. However, unpredictable stressors such as problem behaviors are both inherently burdensome and highlight role discrepancies.
Alternative Mouse Models for Carcinogenicity Assessment: Industry Use and Issues with Pathology Interpretation
Authors: Long Gerald G. , Morton Daniel , Peters Terry , Short Brian , Skydsgaard Mikala
Published: November 2009

The Carcinogenicity Alternative Mouse Models (CAMM) Working Group of the Society of Toxicologic Pathology (STP) surveyed the membership to define current practices and opinions in industry regarding the use of alternative mouse models for carcinogenicity testing. The results of the survey indicated that CAMM are used most often to fulfill a regulatory requirement (e.g., to replace the two-year mouse bioassay) and are being accepted by regulatory agencies. Alternative models are also sometimes used for internal decision making or to address a mechanistic question. The CAMM most commonly used are the p53+/— and rasH2. The rasH2 appears to be the currently accepted model for general carcinogenicity testing. Problems with study interpretation included lack of historic background data, unexpected tumor finding, and tumor identification/characterization of early lesions. Problems with implementation or conduct of the study included extent of the pathology evaluation, numbers of animals, survival, and study duration. Recommendations were developed for, frequency and type of positive control testing, extent of histopathologic examination of test article—treated and positive control animals, current use and future development of diagnostic criteria; increased availability and use of historic data, and use of other genetically modified mice in carcinogenicity testing.
Reliable External Actuation for Full Reachability in Robotic Modular Self-reconfiguration
Authors: White P.J. , Yim M.
Published: November 2009

External actuation in self-reconfigurable modular robots promises to allow modules to shrink down in size. Synchronous external motions promise to allow fast convergence and assembly times. XBot is a modular system that uses synchronous external actuation, but has a limited range of reachable configurations stemming from a single motion primitive of a module rotating about another. This paper proposes to extend the motion primitives by using moves with two modules swinging in a dynamic chain. The feasibility of these motion primitives is proven experimentally. A parameterization of the external actuation motion profiles is explored to define a space of physically valid motion profiles. The larger the space, the more robust the motion primitives will be to inexact initial conditions and to imprecision in the external actuation mechanisms. In addition, this paper proves that a configuration of XBot meta-modules can reach any configuration using just these motion primitives.
Counting Objects with a Combination of Horizontal and Overhead Sensors
Authors: Halvorson Erik , Parr Ronald
Published: November 2009

In this paper we consider the problem of planning sensor observations for a network of overhead sensors which will resolve ambiguities in the output of a horizontal sensor network. More specifically, we address the problem of counting the number of objects detected by the horizontal sensor network, using the overhead network to aim at specific areas to improve the count. We consider several different overhead sensor models. The main theme of our results is that, even though observation planning is intractable for such a network, a simple, greedy algorithm for controlling the overhead sensors guarantees performance with bounded and reasonable suboptimality. Our results are very general and make few assumptions about the specific sensors used.
Small, Fast, and Under Control: Wireless Resonant Magnetic Micro-agents
Authors: Frutiger Dominic R. , Vollmers Karl , Kratochvil Bradley E. , Nelson Bradley J.
Published: November 2009

Primary challenges in the building of untethered submillimeter sized robots include propulsion methods, power supply, and control. We present a novel type of microrobot called MagMite that utilizes a new class of wireless resonant magnetic micro-actuator that accomplishes all three tasks. The term MagMite is derived from Magnetic Mite —a tribute to the underlying magnetic propulsion principle and the micro-scale dimensions of the robot. The device harvests magnetic energy from the environment and effectively transforms it into inertia-and impact-driven mechanical force while being fully controllable. It can be powered and controlled with oscillating fields in the kilohertz range and strengths as low as 2 mT, which is only roughly 50 times the average Earth magnetic field. These microrobotic agents with dimensions less than 300 μm × 300 μm × 70 μm and a total mass of 30—50 μg are capable of moving forward, backward and turning in place while reaching controllable speeds in excess of 12.5 mm s—1 or 42 times the robot’s body length per second. The robots produce enough force to push micro-objects of similar sizes and can be visually servoed through a maze in a fully automated fashion. The prototype devices exhibit an overall degree of flexibility, controllability, and performance unmatched by other microrobots reported in the literature. The robustness of the MagMites leads to high experimental repeatability, which in turn enabled us to successfully compete in the RoboCup 2007 and 2009 Nanogram competitions. In this work it is demonstrated how the robots exhibit a plethora of driving behaviors, how they can operate on a host of unstructured surfaces under both dry and wet conditions, and how they can accomplish fully automated micromanipulation tasks. Various micro-objects ranging from beads to biological entities have been successfully manipulated. To the same end, multi-agent studies have shown great promise to be used in cooperative tasks.
Vision-guided Robot System for Picking Objects by Casting Shadows
Authors: Agrawal Amit , Yu Sun  , Barnwell John , Raskar Ramesh
Published: November 2009

We present a complete vision-guided robot system for model-based three-dimensional (3D) pose estimation and picking of singulated 3D objects. Our system employs a novel vision sensor consisting of a video camera surrounded by eight flashes (light emitting diodes). By capturing images under different flashes and observing the shadows, depth edges or silhouettes in the scene are obtained. The silhouettes are segmented into different objects and each silhouette is matched across a database of object silhouettes in different poses to find the coarse 3D pose. The database is pre-computed using a computer-aided design (CAD) model of the object. The pose is refined using a fully projective formulation of Lowe’s model-based pose estimation algorithm. The estimated pose is transferred to a robot coordinate system utilizing the hand—eye and camera calibration parameters, which allows the robot to pick the object. Our system outperforms conventional systems using two-dimensional sensors with intensity-based features as well as 3D sensors. We handle complex ambient illumination conditions, challenging specular backgrounds, diffuse as well as specular objects, and texture-less objects, on which traditional systems usually fail. Our vision sensor is capable of computing depth edges in real time and is low cost. Our approach is simple and fast for practical implementation. We present real experimental results using our custom designed sensor mounted on a robot arm to demonstrate the effectiveness of our technique.
Excessive Glenohumeral Horizontal Abduction as Occurs during the Late Cocking Phase of the Throwing Motion can be Critical for Internal Impingement
Authors: Mihata Teruhisa , McGarry Michelle H. , Kinoshita Mitsuo , Lee Thay Q.
Published: November 2009

Background

The objective of this study was to determine the effects of increased horizontal abduction with maximum external rotation, as occurs during the late cocking phase of throwing motion, on shoulder internal impingement.

Hypothesis

An increase in glenohumeral horizontal abduction will cause overlap of the rotator cuff insertion with respect to the glenoid and increase pressure between the supraspinatus and infraspinatus tendon insertions on the greater tuberosity and the glenoid.

Study Design

Controlled laboratory study.

Methods

Eight cadaveric shoulders were tested with a custom shoulder testing system with the specimens in 60° of glenohumeral abduction and maximum external rotation. The amount of internal impingement was evaluated by assessing the location of the supraspinatus and infraspinatus articular insertions on the greater tuberosity relative to the glenoid using a MicroScribe 3DLX. Pressure in the posterior-superior quadrant of the glenoid was measured using Fuji prescale film. Data were obtained with the humerus in the scapular plane and 15°, 30°, and 45° of horizontal abduction from the scapular plane.

Results

At 30° and 45° of horizontal abduction, the articular margin of the supraspinatus and infraspinatus tendons was anterior to the posterior edge of the glenoid and less than 2 mm from the glenoid rim in the lateral direction; the contact pressure was also greater than that found in the scapular plane and 15° of horizontal abduction.

Conclusion

Horizontal abduction beyond the coronal plane increased the amount of overlap and contact pressure between the supraspinatus and infraspinatus tendons and glenoid.

Clinical Relevance

Excessive glenohumeral horizontal abduction beyond the coronal plane may cause internal impingement, which may lead to rotator cuff tears and superior labral anterior to posterior (SLAP) lesions.
Effect of Graft Selection on the Incidence of Postoperative Infection in Anterior Cruciate Ligament Reconstruction
Authors: Barker Joseph U. , Drakos Mark C. , Maak Travis G. , Warren Russell F. , Williams Riley J. , Allen Answorth A.
Published: November 2009

Background

Knee joint infection is a potentially devastating complication of anterior cruciate ligament (ACL) reconstruction. There is a theoretical increased risk of infection with the use of allograft material.

Hypothesis

An allograft ACL reconstruction predisposes patients to a higher risk of bacterial infection.

Study Design

Cohort Study; Level of evidence, 3.

Methods

All primary ACL reconstructions performed at our institution between January 2002 and December 2006 were reviewed; 3126 total procedures were identified. A retrospective medical record review was performed to determine the incidence of infection, offending organism, time after surgery until presentation, infection treatment, and graft salvage as an outcome of graft choice.

Results

Of the 3126 ACL reconstructions, 1777 autografts and 1349 allografts were performed. Eighteen infections were identified (0.58%). Infections occurred in 6 of the 1349 allografts (0.44%), 7 of the 1430 bone-patellar tendon-bone (BPTB) autografts (0.49%), and 5 of the 347 hamstring autografts (1.44%). Five grafts were removed because of graft incompetence or loosening: 3 hamstring tendon, 1 BPTB, and 1 allograft. The most common organism isolated was Staphylococcus aureus. Hamstring tendon autograft had an increased incidence of infection compared with both BPTB autograft and allograft (P < .05), with a trend toward a more common need for graft removal (P = .09). Allograft reconstructions were equally likely to have graft salvage as autograft reconstructions.

Conclusion

Hamstring tendon autografts have a higher incidence of infection than BPTB autografts or allografts. The use of allograft material in ACL reconstructions does not increase the risk of infection or the need for graft removal with infection.
Gender Variations in the Levels of Social Support and Risk of Elder Mistreatment in a Chinese Community Population
Authors: Dong XinQi , Simon Melissa A.
Published: November 2009

This study aimed to examine gender differences in social support and risk of elder mistreatment (EM) in a community-dwelling Chinese population. The authors conducted a cross-sectional study of 141 women and 270 men aged 60 years or above. EM was assessed using the modified Vulnerability to Abuse Screening Scale (VASS), and social support was measured using the Social Support Index (SSI). After adjusting for sociodemographic factors, socioeconomic status, depression, loneliness, and medical conditions, lower levels of social support were associated with an increased odds of EM in men (odds ratio [OR] = 5.35, 95% confidence interval [CI] = 2.18-13.15, p < .001) and in women (OR = 5.39, 95% CI = 1.95-14.85, p < .001). Perceived social support, but not instrumental social support, was associated with increased odds of EM in men and women. These findings could have important implication for health care professional and social services agencies in the detection, management, and prevention of EM among the aging Chinese population.
Behind the Baton: Exploring Autoethnographic Writing in a Musical Context
Authors: Bartleet Brydie-Leigh
Published: November 2009

In this article, the author considers how music can expand the creative possibilities of autoethnography. Likewise, the author explores how autoethnography can offer musicians a means to reflect on their creative work in culturally insightful ways. To “play out” these disciplinary considerations, the author crafts an autoethnographic narrative that centers on her own creative practice as a conductor. Moving between description and action, dialogue and introspection, the narrative reveals some of the complexities of reflecting and writing about music in this way. While this narrative is grounded in the author’s lived experiences, it reveals significant broader issues about the process of doing autoethnography, the conducting profession, and the culture and practice of music-making at large.
Annie Marion MacLean, Feminist Pragmatist and Methodologist
Authors: Deegan Mary Jo , Hill Michael R. , Wortmann Susan L.
Published: November 2009

Annie Marion MacLean was a major Chicago sociologist and methodologist. She was profoundly influenced by the gendered division of labor in sociology during her era. MacLean combined her work with the men and women of the early Chicago school of sociology and the women of Hull-House, an early social settlement. As a feminist pragmatist, MacLean was both a theorist and practitioner who used qualitative and quantitative methods. She set precedents in the Chicago school of ethnography, participant observation, and critical methodology. MacLean, however, was not the “mother” of ethnography. Harriet Martineau holds a far stronger claim to be a founding contributor to the origin and development of ethnographic methodologies in the social sciences.
Don’t Ask, Don’t Tell: Coming Out in an Alcoholic Family
Authors: Tillmann Lisa M.
Published: November 2009

This article invites readers inside emotional and relational dynamics of coming out as gay in an alcoholic family system. Taking an interpretive approach to research, focused on how participants make sense of and make meaning from their lived experience, “Don’t Ask, Don’t Tell” offers a longitudinal and narrative ethnographic account of family secrecy and disclosure.
Ethnographic Methods in Nonprofit Management
Authors: Flinn Juliana
Published: November 2009

As undergraduate programs in nonprofit management education proliferate, they increasingly incorporate service learning, experiential learning, and an emphasis on inclusiveness and diversity.To effectively face these challenges, such programs would do well to look to cultural anthropology, especially the methods of ethnographic research. Cultural anthropology has far more to offer than a list of behavioral traits about obscure peoples in the world: It offers a methodology for how to learn through experiences, a number of strategies to promote inclusiveness, and a framework that promotes an openness to having one’s assumptions challenged. This article provides an analysis of the use and value of ethnographic methods while working for Big Brothers Big Sisters in rural Alaska, followed by recommendations for incorporating anthropological methods and concepts into nonprofit management education.
The Motivation of Undergraduate Music Students: The Impact of Identification and Talent Beliefs on Choosing a Career in Music Education
Authors: Jones Brett D. , Parkes Kelly A.
Published: November 2009

The purpose of this study was to examine the reasons why undergraduate music students choose a career in teaching classroom music and how these reasons are related to their beliefs about their identification with teaching classroom music, identification with music performance, teaching talent, and performance talent. Participants included 143 students enrolled in music performance and music education programs at seven large U.S. universities who completed an online questionnaire. One major reason that students chose a career in teaching music was that teaching music had become part of their identity, a part that was separate from their music performance identity. In many cases, the motivation for developing this identity was their belief that becoming a classroom music teacher would allow them to help students by acting as a role model. The findings suggest that further research related to career choice in music education should include the psychological construct of identification with teaching classroom music.
Using the PCL-R to Help Estimate the Validity of Two Self-Report Measures of Psychopathy With Offenders
Authors: Poythress Norman G. , Lilienfeld Scott O. , Skeem Jennifer L. , Douglas Kevin S. , Edens John F. , Epstein Monica , Patrick Christopher J.
Published: November 2009

Two self-report measures of psychopathy, Levenson’s Primary and Secondary Psychopathy scales (LPSP) and the Psychopathic Personality Inventory (PPI), were administered to a large sample of 1,603 offenders. The most widely researched measure of criminal psychopathy, the Hare Psychopathy Checklist—Revised (PCL-R), served as a provisional referent for estimating the construct validity of these self-report measures with offenders. Compared with the LPSP, the PPI displayed higher zero-order correlations with the PCL-R, better convergent and discriminant validity, and more consistent incremental utility in predicting PCL-R scores. Furthermore, using a variant of Westen and Rosenthal’s approach to evaluating the construct validity of a new measure, compared with the LPSP, the PPI’s pattern of associations with measures of 35 external criterion variables was more similar to the pattern observed for the PCL-R. Results generally provide stronger support for the validity of the PPI than the LPSP in offender populations using the PCL-R as a provisional benchmark, particularly for assessing interpersonal and affective features of psychopathy.
Prenatal Care Utilization in Excess of Recommended Levels: Trends From 1985 to 2004
Authors: Lauderdale Diane S. , VanderWeele Tyler J. , Siddique Juned , Lantos John D.
Published: November 2009

Indexes of prenatal care adequacy distinguish care that includes more than the recommended number of visits because extra visits may signal a high-risk pregnancy. Using Natality files from 1985 to 2004, the authors found such “superadequate” care increased from 19.5% of pregnancies in 1985 to 30.0% in 2004. Although there were dramatic changes in the demographics of childbearing over the same 20 years, those changes do not explain the increase in extra prenatal visits: Superadequate care increased within every stratum defined by maternal birthplace, race, age, education, gravidity, marital status, and multiple birth. Had the demographics of childbearing not changed since 1985, the superadequate rate would be just as high in 2004. Although randomized controlled trials have found that reduced visit schedules for low-risk women do not lead to worse maternal or perinatal outcomes, the cost-effectiveness of more intense visit schedules is not known.
MBA lecturers’ curriculum interests in leadership
Authors: Garcia Eric Jean
Published: November 2009

This article aims to provide insight into MBA lecturers’ curriculum interests in relation to the topic of leadership. Central to this inquiry is the exploration of MBA lecturers’ beliefs and expectations of leadership learning. An attempt is made to categorize the purpose of leadership study in five English and French MBAs by investigating lecturers’ assumptions about what counts as a leadership success in the corporate world. Guided by the work of Habermas on human knowledge interests, the main value of this inquiry is to provide research-based evidence of the prevailing interests in the teaching of leadership in MBA curricula. The analysis reveals that, although driven by different pedagogical motives, the majority of MBA lecturers are not committed to providing participants with a full understanding of leadership that might serve people and society beyond mere business ends.
A MacIntyrian perspective on organizational learning
Authors: Halliday John , Johnsson Mary
Published: November 2009

This article examines the meaning of organizational learning (OL) from a MacIntyrian perspective. Key MacIntyrian terms such as practice, institution and relational dependence are explained and related to OL. It is argued that much of the literature concerned with OL, including that concerned with Communities of Practice, misses the moral and relational dimensions of organizations. An alternative MacIntyrian perspective considers the enduring nature of practices which transcends both individual and organizational interests. The notion of relational dependence extends practical involvement to consideration of what is in the collective interest even where people fundamentally disagree. Such dependence involves generosity towards others and the recognition that conflict is inevitable and desirable. The article concludes with an outline of what OL might be and some indicators of success.