bluuebunny/crossref_metadata_2025 huggingface dataset:
A known mutation in GJB6 in a large Chinese family with hidrotic ectodermal dysplasia
Authors: Yang R. , Hu ZL. , Kong QT. , Li WW. , Zhang LL. , Du X. , Huang SY. , Xia XY. , Sang H.
Published: May 2016

Background

Hidrotic ectodermal dysplasia (HED), also named as Clouston syndrome, is a rare autosomal dominant disease. Mutations in GJB6, GJB2 and GJA1 are related to HED.

Objective

Summarize the clinical feature and analyse the mutation of the GJB6 gene in a large Chinese family with HED.

Methods

We collected a very large Chinese family with HED. Clinical information was analysed. Blood samples were obtained. The whole coding region of GJB6 was amplified by polymerase chain reaction and sequenced. The results were further confirmed at mRNA level by reverse transcription polymerase chain reaction.

Results

Sequence analysis identified a heterozygous missense mutation c.263C>T (p.A88V) in genomic DNAs of 25 patients, and this mutation was excluded from 14 normal individuals in this HED family and 218 unrelated, population‐matched control individuals. The transcription of mutated allele was confirmed by RT‐PCR of Cx30 mRNA from proband,s scalp skin. We found a novel phenotype of this variant in this Chinese HED family.

Conclusion

Our data reveals that a recurrent mutation p.A88V in GJB6 played a pathogenic role in a large Chinese family and emphasizes the importance of gene test in this congenital disorder.
Hospital care following emergency admission: a critical incident case study of the experiences of patients with advanced lung cancer and Chronic Obstructive Pulmonary Disease
Authors: Bailey Cara , Hewison Alistair , Karasouli Eleni , Staniszewska Sophie , Munday Daniel
Published: May 2016

Aims and objectives

To explore the experiences of patients with advanced Chronic Obstructive Pulmonary Disease (COPD) and lung cancer, their carers and healthcare professionals following emergency admission to acute care hospital.

Background

Emergency admissions of people with lung cancer and COPD have increased and there is global concern about the number of patients who die in hospital. The experience of patients with advanced lung cancer and COPD admitted to hospital as an emergency when nearing the end of life has not previously been investigated.

Design

Qualitative critical incident case study.

Methods

Semistructured interviews were conducted with 39 patients (15 with COPD and 24 with lung cancer), 20 informal carers and 50 healthcare professionals, exploring patients’ experiences of emergency hospital admission. Interviews took place after admission and following discharge. Participants nominated relatives and healthcare professionals for interview. Data were analysed thematically.

Results

Patients were satisfied with their ‘emergency’ care but not the care they received once their initial symptoms had been stabilised. The poorer quality care they experienced was characterised by a lack of attention to their fundamental needs, lack of involvement of the family, poor communication about care plans and a lack of continuity between primary and secondary care. A conceptual model of ‘spectacular’ and ‘subtacular’ trajectories of care was used to relate the findings to the wider context of health care provision.

Conclusion

The complex nature of illness for patients with advanced respiratory disease makes emergency hospital admissions likely. Whilst patients (with COPD and lung cancer) were satisfied with care in the acute ‘spectacular’ phase of their admission, more attention needs to be given to the continuing care needs of patients in the ‘subtacular’ phase.

Relevance to Clinical Practice

This is the first study to explore the patient experience of acute care following an emergency admission and identifies where there is potential for care to be improved.
From expert generalists to ambiguity masters: using ambiguity tolerance theory to redefine the practice of rural nurses
Authors: Knight Kaye , Kenny Amanda , Endacott Ruth
Published: May 2016

Aims and objectives

To redefine the practice of rural nurses and describe a model that conceptualises the capabilities and characteristics required in the rural environment.

Background

The way in which the practice of rural nurses has been conceptualised is problematic. Definitions of rural nursing have been identified primarily through the functional context of rural health service delivery. The expert generalist term has provided a foundation theory for rural nurses with understandings informed by the scope of practice needed to meet service delivery requirements. However, authors exploring intrinsic characteristics of rural nurses have challenged this definition, as it does not adequately address the deeper, intangible complexities of practice required in the rural context. Despite this discourse, an alternative way to articulate the distinctive nature of rural nursing practice has eluded authors in Australia and internationally.

Design

A theoretical paper based on primary research.

Methods

The development of the model was informed by the findings of a study that explored the nursing practice of managing telephone presentations in rural health services in Victoria, Australia. The study involved policy review from State and Federal governments, nursing and medical professional bodies, and five rural health services; semi‐structured interviews with eight Directors of Nursing, seven registered nurses and focus group interviews with eight registered nurses.

Results

An ambiguity tolerance model drawn from corporate global entrepreneurship theory was adapted to explain the findings of the study. The adapted model presents capabilities and characteristics used by nurses to successfully manage the ambiguity of providing care in the rural context.

Conclusions

Redefining the practice of rural nurses, through an adapted theory of ambiguity tolerance, highlights nursing characteristics and capabilities required in the rural context. This perspective offers new ways of thinking about the work of rural nurses, rural nurse policy, education, recruitment, retention and clinical governance.

Relevance to clinical practice

A greater understanding of rural nurse practice will assist in achieving positive care outcomes in an environment with competing stakeholder needs, and limited resources and options for care.
Practicability of prenatal testing using lectin‐based enrichment of fetal erythroblasts
Authors: Kanda Eriko , Yura Hirofumi , Kitagawa Michihiro
Published: May 2016

Aim

The aim of this study was to investigate the practicability and efficiency of lectin‐based isolation of fetal erythroblasts for clinical use in non‐invasive prenatal testing.

Methods

Peripheral blood samples were collected from 39 pregnant women. Leukocytes were removed with an anti‐CD45 antibody after density gradient centrifugation. After blood cells were attached to slides by binding to a galactose‐specific lectin and galactose‐bound vinyl polymer, the slides were stained with May–Grünwald–Giemsa stain and cells were classified by automated image analysis based on their size and the nuclear area/cytoplasmic area ratio. In 14 samples from the women with male fetuses, fetal origin of the isolated erythroblasts was confirmed by detecting the Y chromosome using fluorescence in situ hybridization. In eight samples, single erythroblasts were collected by the laser capture microdissection technique for amplification of the sex‐determining region Y gene to confirm fetal origin.

Results

Panning with an anti‐CD45 antibody achieved stable removal of leukocytes without aggregation. In all samples, erythroblasts were successfully identified by automated image analysis (18–6000/10 mL of blood). The number of slides required to examine 10 mL of blood ranged from one to six, which was reasonable for clinical use. The Y chromosome was detected in 7.5–43.6% of erythroblasts by fluorescence in situ hybridization, and the sex‐determining region Y gene was amplified in seven of eight samples.

Conclusion

The combination of lectin‐based erythroblast isolation and automated image analysis is a practical and efficient method for isolating fetal erythroblasts as a source of fetal genomes.
Understanding Student Perceptions of Stress in Creativity–Based Higher Education Programs: A Case Study in Interior Architecture
Authors: Smith Dianne , Lilly Linda
Published: May 2016

Stress—as an aspect in the contemporary university context—reflects the personal and professional demands felt across many parts of society. The research team sought to understand how stress is spoken about as well as experienced in professional creative courses. Terms such as stress, stressful, or being stressed represent both the negative and positive aspects associated with learning. As interior architecture (IA) educators, could the positive aspects be facilitated in the future, while the negative aspects are reduced, by building on the knowledge gained through this study? A number of issues were revealed through which tension was demonstrated as grounds for stress to develop. The issues arising include conflicting expectations between the university, staff, and students; lack of student understanding of the core discipline activities and culture; student levels of maturity; individual variation in response to learning situations, such as design studios, group work, or industry placements; and the university context and culture. In turn, these issues were often linked to miscommunication—that is, although concepts and issues were being addressed through interactions in the university context, what was being said or demonstrated was not what was being heard or understood and applied by the students. Miscommunication can be an instigator of stressful situations for students, and if this manifests in a negative way, students can experience physical, cognitive, and emotional issues that can alter their learning potential and enjoyment. For lecturers in contemporary universities, miscommunication is relevant, and a need to improve clarity and to foster shared meaning seems evident. Initially, a summary of background literature sets the scene for the study. Then, our action–based methodology is outlined before discussing the issues identified and the implications they hold for learning and teaching as well as for future research. The findings are presented to also inform staff and curriculum designers involved in other creative professional courses such as design, architecture, performance, film, and interior design.
The effects of cordycepin on the cell proliferation, migration and apoptosis in human lung cancer cell lines A549 and NCI-H460
Authors: Tao Xiandong , Ning Ye , Zhao Xuewei , Pan Tiewen
Published: May 2016

Objectives

Our study aimed to evaluate the effect of cordycepin on human lung cancer cell lines A549 and NCI-H460.

Methods

Human lung cancer A549 cells and NCI-H460 cells were treated with different concentrations of cordycepin for different times. Cells incubated without cordycepin were defined as a control. The cell proliferation, migration and apoptosis were, respectively, determined by MTT assay, transwell migration assay and flow cytometry. Additionally, the expression levels of related proteins associated with cell cycle, epithelial–mesenchymal transition (EMT) and apoptosis were examined.

Key findings

The survival rate of A549 cells and NCI-H460 cells treated with cordycepin significantly decreased compared with untreated cells in a concentration-dependent manner, while the apoptosis rate increased. The migration number of cells treated with cordycepin significantly decreased as the increase in concentration. qRT-PCR and Western blot analysis showed that the aberrant expression of related molecules associated with cell cycle, migration and apoptosis was observed in the lung cancer cells, such as cyclin B, cyclin E, MMP-9, caspase-3 and Bcl-2.

Conclusions

Cordycepin may exert inhibitory effects on the development of human lung cancer via inhibiting cell proliferation, suppressing migration and inducing apoptosis, suggesting that cordycepin may have therapeutic potential for the treatment of this disease.
Concordance of actigraphy with polysomnography in children with and without attention‐deficit/hyperactivity disorder
Authors: Waldon Jessica , Begum Esmot , Gendron Melissa , Rusak Benjamin , Andreou Pantelis , Rajda Malgorzata , Corkum Penny
Published: May 2016

This study sought to: (1) compare actigraphy‐derived estimated sleep variables to the same variables based on the gold‐standard of sleep assessment, polysomnography; (2) examine whether the correlations between the measures differ between children with attention‐deficit/hyperactivity disorder and typically developing children; and (3) determine whether these correlations are altered when children with attention‐deficit/hyperactivity disorder are treated with medication. Participants (24 attention‐deficit/hyperactivity disorder; 24 typically developing), aged 6–12 years, completed a 1‐week baseline assessment of typical sleep and daytime functioning. Following the baseline week, participants in the attention‐deficit/hyperactivity disorder group completed a 4‐week blinded randomized control trial of methylphenidate hydrochloride, including a 2‐week placebo and 2‐week methylphenidate hydrochloride treatment period. At the end of each observation (typically developing: baseline; attention‐deficit/hyperactivity disorder: baseline, placebo and methylphenidate hydrochloride treatment), all participants were invited to a sleep research laboratory, where overnight polysomnography and actigraphy were recorded concurrently. Findings from intra‐class correlations and Bland–Altman plots were consistent. Actigraphy was found to provide good estimates (e.g. intra‐class correlations >0.61) of polysomnography results for sleep duration for all groups and conditions, as well as for sleep‐onset latency and sleep efficiency for the typically developing group and attention‐deficit/hyperactivity disorder group while on medication, but not for the attention‐deficit/hyperactivity disorder group during baseline or placebo. Based on the Bland–Altman plots, actigraphy tended to underestimate for sleep duration (8.6–18.5 min), sleep efficiency (5.6–9.3%) and sleep‐onset latency, except for attention‐deficit/hyperactivity disorder during placebo in which actigraphy overestimated (−2.1 to 6.3 min). The results of the current study highlight the importance of utilizing a multimodal approach to sleep assessment in children with attention‐deficit/hyperactivity disorder.
Immediate effects of phototherapy on sleep in very preterm neonates: an observational study
Authors: Cremer Martin , Jost Kerstin , Gensmer Anna , Pramana Isabelle , Delgado‐Eckert Edgar , Frey Urs , Schulzke Sven M. , Datta Alexandre N.
Published: May 2016

Process C (internal clock) and Process S (sleep–wake homeostasis) are the basis of sleep–wake regulation. In the last trimester of pregnancy, foetal heart rate is synchronized with the maternal circadian rhythm. At birth, this interaction fails and an ultradian rhythm appears. Light exposure is a strong factor influencing the synchronization of sleep–wake processes. However, little is known about the effects of phototherapy on the sleep rhythm of premature babies. It was hypothesized that sleep in preterm infants would not differ during phototherapy, but that a maturation effect would be seen. Sleep states were studied in 38 infants born < 32 weeks gestational age and/or < 1 500 g birth weight. Videos of 3 h were taken over the first 5 days of life. Based on breathing and movement patterns, behavioural states were defined as: awake; active sleep; or quiet sleep. Videos with and without phototherapy were compared for amounts of quiet sleep and active states (awake + active sleep). No significant association between phototherapy and amount of quiet sleep was found (P = 0.083). Analysis of videos in infants not under phototherapy revealed an increase in time spent awake with increasing gestational age. The current data suggest that the ultradian rhythm of preterm infants seems to be independent of phototherapy, supporting the notion that sleep rhythm in this population is mainly driven by their internal clock.
Extremity in Congress: Communications versus Votes
Authors: Cormack Lindsey
Published: May 2016

I propose a theory of legislator‐to‐constituent communication that describes a relationship between the types of votes a legislator reveals and the partisan composition of her constituency. To test this theory, I use an original data set of 40,000 official communications containing 30,000 vote revelations from the 111th Congress. I find evidence substantiating this theory; the extent to which a legislator endeavors to appear more ideologically extreme in communications varies systematically with the relative amounts of different types of voters in her district. This result is contrasted with an analysis of voting extremism where I find that the ideological preferences of donors better explain voting patterns.
Electoral Rules and Party Switching: How Legislators Prioritize Their Goals
Authors: Klein Elad
Published: May 2016

Stemming from ambition theory, a vast body of studies has demonstrated how politicians' pursuits of different goals can explain their behaviors. Among other goals, politicians strive for re‐election or to attain a better office. However, little is known about the way politicians prioritize these goals. This article uses the phenomenon of legislative party switching to address this void and examines how hierarchy between goals determines legislator strategies. The study exploits the 2008 Romanian electoral reform, which rendered the electoral system more candidate centered. Drawing on data from more than 3,900 individual‐level observations over the period from 1996 to 2012, this article shows how vote incentives alter the trade‐offs between re‐election and office motivations. The findings suggest that politicians will pursue office goals only if the goal of re‐election is to be achieved.
Mysticete migration revisited: are Mediterranean fin whales an anomaly?
Authors: Geijer Christina K.A. , Notarbartolo di Sciara Giuseppe , Panigada Simone
Published: May 2016

The generally accepted model of Mysticete whale migration is that most individuals undertake seasonal migrations between high and low latitudes. Although numerous exceptions have been described in the literature, the traditional model remains unexamined. This paper represents the first ‘official’ challenge to the traditional model of Mysticete migration.

We set out to review the current state of knowledge on the Mediterranean fin whale migratory pattern, and to examine whether the small, resident population in the Mediterranean is an anomaly within the framework of the traditional model of Mysticete migration. We investigated the prevalence of alternative migratory strategies among the Mysticete whales, reviewing the migratory habits of the Mediterranean fin whales and those of other fin whale and baleen whale populations.

We reach three main conclusions. First, the seasonal behaviour of the resident Mediterranean fin whales is highly dynamic, and a decade of research has not clarified prevailing uncertainties regarding migration patterns. Second, migration strategies similar to those observed in the Mediterranean fin whales are commonly seen in other populations of baleen whales. Third, the traditional model of whale migration is too simplified to describe the repertoire of Mysticete migratory behaviours accurately.

We argue that the paradigm of baleen whale migration warrants further scrutiny to account for more complex movement strategies. We suggest that Mysticete migration should be thought of as a continuum of different strategies that have evolved in the face of different selective pressures. Instead of representing an exception to the rule, the resident Mediterranean fin whales may in fact fall towards one end of a larger spectrum of migratory behaviours. A greater knowledge of ecological factors, reproductive patterns, and local adaptations will be needed to understand the evolutionary mechanisms behind the diversity of migratory habits.
Social influence in childhood obesity interventions: a systematic review
Authors: Jalali M. S. , Sharafi‐Avarzaman Z. , Rahmandad H. , Ammerman A. S.
Published: May 2016

The objective of this study is to understand the pathways through which social influence at the family level moderates the impact of childhood obesity interventions. We conducted a systematic review of obesity interventions in which parents' behaviours are targeted to change children's obesity outcomes, because of the potential social and environmental influence of parents on the nutrition and physical activity behaviours of children. PubMed (1966–2013) and the Web of Science (1900–2013) were searched, and 32 studies satisfied our inclusion criteria. Results for existing mechanisms that moderate parents' influence on children's behaviour are discussed, and a causal pathway diagram is developed to map out social influence mechanisms that affect childhood obesity. We provide health professionals and researchers with recommendations for leveraging family‐based social influence mechanisms to increase the efficacy of obesity intervention programmes. © 2016 World Obesity
Posterior reversible encephalopathy syndrome after pediatric heart transplantation: Increased risk for children with preexisting Glenn/Fontan physiology
Authors: Eilers Braiden , Albers Erin , Law Yuk , McMullan D. Mike , Shaw Dennis , Kemna Mariska
Published: May 2016

Identification of risk factors for PRES after organ transplant can improve early detection and avoid permanent neurological injury. High calcineurin‐inhibitor levels and hypertension are recognized risk factors for PRES in adult transplant recipients. Limited data exist regarding PRES after pediatric HTx, with studies limited to case reports. We performed a retrospective review of 128 pediatric HTx recipients to identify risk factors for PRES. Seven of 128 (5.5%) recipients developed PRES at a median of 10 days (5–57) after HTx. The median age of recipients with PRES was 10.0 yr (5.7–19.0), compared to 1.4 yr (0.0–19.8) for recipients without PRES (p = 0.010). Fewer than half of recipients with PRES had elevated post‐transplant calcineurin‐inhibitor levels (n = 3) and/or preceding severe hypertension (n = 3). Four of seven who developed PRES (57%) had pretransplant Glenn or Fontan physiology (G/F). G/F was a significant risk factor for PRES (RR 4.99, 95% CI: 1.19–21.0, p = 0.036). Two recipients (29%), both with severe PRES, had residual neurological symptoms. In summary, PRES occurred in 5.5% of pediatric HTx recipients and presented early after HTx. All recipients with PRES were > 5 yr. Patients with pretransplant G/F were at increased risk, a risks factor not previously described.
Managing Electricity Peak Loads in Make‐To‐Stock Manufacturing Lines
Authors: Papier Felix
Published: May 2016

In this article, we study the control of stochastic make‐to‐stock manufacturing lines in the presence of electricity costs. Electricity costs are difficult to manage because unit costs increase with the total load, that is, the amount of electricity needed by the manufacturing line at a certain point in time. We demonstrate that standard methods for controlling manufacturing lines cannot be used and that standard analytic results for stochastic manufacturing lines do not hold in the presence of electricity costs. We develop a control policy that balances electricity costs with inventory holding and backorder costs. We derive closed‐form expressions and analytic properties of the expected total cost for manufacturing lines with two workstations and demonstrate the accuracy and robustness of the policy for manufacturing lines with more than two workstations. The results indicate that avoiding electricity peak loads requires additional investment in manufacturing capacity and higher inventory and backorder costs. Our approach also applies to companies which aim at reducing their carbon emissions in addition to their operating costs.
VvPIP2;4N aquaporin involvement in controlling leaf hydraulic capacitance and resistance in grapevine
Authors: Vitali Marco , Cochard Hervé , Gambino Giorgio , Ponomarenko Alexandre , Perrone Irene , Lovisolo Claudio
Published: May 2016

Hydraulic capacitance (C) in a plant tissue buffers the xylem tension, storing and releasing water and has been highlighted in recent years as an important factor that affects water relations such as drought tolerance and embolism formation. Aquaporins (AQPs) are well known to control leaf hydraulic resistance (Rh) but their role in the control of C is unknown. Here, we assess Rh and C on detached grapevines wild‐type (WT) (cv. Brachetto) leaves and over‐expressing the aquaporin gene VvPIP2;4N (OE). For this purpose, we developed a new method inspired from the pressure‐volume curve technique and the rehydration‐kinetic‐method, which allowed us to monitor the dynamics of dehydration and rehydration in the same leaf. The recovery after dehydration was measured in dark, light non‐transpirative conditions, light‐transpirative conditions and light‐transpirative condition adding abscisic acid. Pressurizing to dehydrate leaves in the OE line, the recorded Rh and C were respectively lower and higher than those in the WT. The same results were obtained in the dark recovery by rehydration treatment. In the presence of light, either when leaves transpired or not (by depressing vapor pressure deficit), the described effects disappeared. The change in Rh and C did not affect the kinetics of desiccation of detached leaves in dark in air, in OE plants compared to WT ones. Our study highlighted that both Rh and C were influenced by the constitutive over‐expression of VvPIP2;4N. The effect of AQPs on C is reported here for the first time and may involve a modulation of cell reflection coefficient.
Bronchodilator responsiveness of peripheral airways in smokers with normal spirometry
Authors: Jetmalani Kanika , Chapman David G. , Thamrin Cindy , Farah Claude S. , Berend Norbert , Salome Cheryl M. , King Gregory G.
Published: May 2016

Background and objective

Cigarette smoke exposure increases airway smooth muscle (ASM) contractility. Abnormalities in peripheral airway function in smokers with normal spirometry could be due to the effects of ASM tone. We aimed to determine the contribution of ASM tone to peripheral airway function in smokers with normal spirometry from the response to bronchodilator (BD).

Methods

Ventilation heterogeneity in peripheral conductive (Scond) and acinar (Sacin) airways were measured in 50 asymptomatic smokers and 20 never‐smokers using multiple breath nitrogen washout, before and 20 min after inhalation of 200 µg salbutamol and 80 µg ipratropium bromide. Z‐scores were calculated to define abnormality in Sacin and Scond.

Results

Nineteen smokers had abnormal Sacin, and 12 had abnormal Scond; 7 had abnormalities in both. After BD, Sacin improved in smokers with normal Sacin (6.5 ± 15.9%, P = 0.02), smokers with abnormal Sacin (9.2 ± 16.9%, P = 0.03) and in control subjects (11.7 ± 18.2%, P = 0.01), with no differences in improvements between groups. Sacin remained abnormal in 15/19 smokers and their post‐BD values correlated with smoking exposure (r = 0.53, P = 0.02). After BD, Scond improved in smokers with abnormal Scond (28.3 ± 15.9%, P = 0.002) and normalized in 9/12 subjects, but not in those with normal Scond (0.25 ± 32.7%, P = 0.44) or control subjects (−1.7 ± 21.2%, P = 0.64).

Conclusion

In smokers with normal spirometry, abnormal conductive airway function could be attributed to increased bronchomotor tone. In contrast, bronchomotor tone in acinar airways is unaffected by smoking and functional abnormality. There may be different causal mechanisms underlying acinar and conductive airway abnormalities in smokers with normal spirometry.
Cross‐cultural validity and measurement invariance of the Organizational Stressor Indicator for Sport Performers (OSI‐SP) across three countries
Authors: Arnold R. , Ponnusamy V. , Zhang C.‐Q. , Gucciardi D. F.
Published: May 2016

Organizational stressors are a universal phenomenon which can be particularly prevalent and problematic for sport performers. In view of their global existence, it is surprising that no studies have examined cross‐cultural differences in organizational stressors. One explanation for this is that the Organizational Stressor Indicator for Sport Performers (OSI‐SP; Arnold, Fletcher, & Daniels, 2013), which can comprehensively measure the organizational pressures that sport performers have encountered, has not yet been translated from English into any other languages nor scrutinized cross‐culturally. The first purpose of this study, therefore, was to examine the cross‐cultural validity of the OSI‐SP. In addition, the study aimed to test the equivalence of the OSI‐SP's factor structure across cultures. British (n = 379), Chinese (n = 335), and Malaysian (n = 444) sport performers completed the OSI‐SP. Confirmatory factor analyses confirmed the cross‐cultural validity of the factorial model for the British and Malaysian samples; however, the overall model fit for the Chinese data did not meet all guideline values. Support was provided for the equality of factor loadings, variances, and covariances on the OSI‐SP across the British and Malaysian cultures. These findings advance knowledge and understanding on the cross‐cultural existence, conceptualization, and operationalization of organizational stressors.
Evaluation of supraspinatus strengthening exercises based on fiber bundle architectural changes
Authors: Sachdeva R. , Farthing J. P. , Kim S. Y.
Published: May 2016

Supraspinatus strengthening is an integral part of rehabilitation programs. However, there is disparity regarding the best exercise. Thus, we investigated the effects of supraspinatus strengthening exercises on muscle fiber bundle architecture using real‐time ultrasound. Participants were randomized into full‐can (FC; n = 12), empty‐can (EC; n = 11,) and prone horizontal abduction (PHA; n = 11) groups and performed three sessions/week for 8 weeks. Each session involved four sets of exercise for weeks 1–4 and six sets for weeks 5–8 with eight repetitions/set. Images of supraspinatus were captured in 0° (relaxed) and 60° (contracted) glenohumeral abduction. Fiber bundle length (FBL), pennation angle, and muscle thickness were measured at beginning, mid, and end of training. Maximum isometric abduction strength was measured in full‐can, empty‐can, and prone horizontal abduction positions using a hand‐held dynamometer. FBL decreased after 4 weeks in FC [relaxed: Δ = −0.54 cm, P = 0.001, d = 0.92; contracted: Δ = −0.27 cm, P = 0.008, d = 0.27] and EC [relaxed: Δ = −0.59 cm, P = 0.008, d = 0.86; contracted: Δ = −0.36 cm, P = 0.013, d = 0.59], but not in PHA [relaxed: Δ = −0.11, P = 0.121, d = 0.31; contracted: Δ = −0.06 cm, P = 0.486, d = 0.13]. Strength increased significantly from week 4–8 only in PHA (Δ = +0.96 kg, P = 0.004, d = 0.47) when tested in prone horizontal abduction position. Maintenance of FBL with increased strength indicates prone horizontal abduction may be a better exercise to strengthen supraspinatus.
Importance of Patella, Quadriceps Forces, and Depthwise Cartilage Structure on Knee Joint Motion and Cartilage Response During Gait
Authors: Halonen K. S. , Mononen M. E. , Jurvelin J. S. , Töyräs J. , Kłodowski A. , Kulmala J.-P. , Korhonen R. K.
Published: May 2016

In finite-element (FE) models of the knee joint, patella is often omitted. We investigated the importance of patella and quadriceps forces on the knee joint motion by creating an FE model of the subject's knee. In addition, depthwise strains and stresses in patellar cartilage with different tissue properties were determined. An FE model was created from subject's magnetic resonance images. Knee rotations, moments, and translational forces during gait were recorded in a motion laboratory and used as an input for the model. Three material models were implemented into the patellar cartilage: (1) homogeneous model, (2) inhomogeneous (arcadelike fibrils), and (3) random fibrils at the superficial zone, mimicking early stages of osteoarthritis (OA). Implementation of patella and quadriceps forces into the model substantially reduced the internal–external femoral rotations (versus without patella). The simulated rotations in the model with the patella matched the measured rotations at its best. In the inhomogeneous model, maximum principal stresses increased substantially in the middle zone of the cartilage. The early OA model showed increased compressive strains in the superficial and middle zones of the cartilage and decreased stresses and fibril strains especially in the middle zone. The results suggest that patella and quadriceps forces should be included in moment- and force-driven FE knee joint models. The results indicate that the middle zone has a major role in resisting shear forces in the patellar cartilage. Also, early degenerative changes in the collagen network substantially affect the cartilage depthwise response in the patella during walking.
Complementarity Techniques for Minimal Coordinate Contact Dynamics
Authors: Mylapilli Harshavardhan , Jain Abhinandan
Published: May 2016

In this paper, nonsmooth contact dynamics of articulated rigid multibody systems is formulated as a complementarity problem. Minimal coordinate (MC) formulation is used to derive the dynamic equations of motion as it provides significant computational cost benefits and leads to a smaller-sized complementarity problem when compared with the frequently used redundant coordinate (RC) formulation. Additionally, an operational space (OS) formulation is employed to take advantage of the low-order structure-based recursive algorithms that do not require mass matrix inversion, leading to a further reduction in these computational costs. Based on the accuracy with which Coulomb's friction cone is modeled, the complementarity problem can be posed either as a linear complementarity problem (LCP), where the friction cone is approximated using a polygon, or as a nonlinear complementarity problem (NCP), where the friction cone is modeled exactly. Both formulations are studied in this paper. These complementarity problems are further recast as nonsmooth unconstrained optimization problems, which are solved by employing a class of Levenberg–Marquardt (LM) algorithms. The necessary theory detailing these techniques is discussed and five solvers are implemented to solve contact dynamics problems. A simple test case of a sphere moving on a plane surface is used to validate these solvers for a single contact, whereas a 12-link complex pendulum example is chosen to compare the accuracy of the solvers for the case of multiple simultaneous contacts. The simulation results validate the MC-based NCP formulations developed in this paper. Moreover, we observe that the LCP solvers deliver accuracy comparable to that of the NCP solvers when the friction cone direction vectors in the contact tangent plane are aligned with the sliding contact velocity at each time step. The theory and simulation results show that the NCP approach can be seamlessly recast into an MC OS formulation, thus allowing for accurate modeling of frictional contacts, while at the same time reducing overall computational costs associated with contact and collision dynamics problems in articulated rigid body systems.
Tool Load Sensitivity Against Multidimensional Process Influences in Microblanking of Copper Foils With Silicon Punches
Authors: Hildering Sven , Michalski Markus , Engel Ulf , Merklein Marion
Published: May 2016

The continuous trend toward miniaturization of metallic microparts of high quality at low costs results in the need of appropriate production methods. Mechanical manufacturing processes like forming and blanking meet these demands. One major challenge for the application of them are the so-called size effects. Especially, the downsizing of the required manufacturing tools and adequate positioning cause higher effort with increasing miniaturization. One promising approach for downsizing of tools is the transfer of knowledge from microsystems technology. This study shows the process behavior of etched silicon punches in microblanking operations. For the application as tool material especially, the brittle material behavior and sensitivity against tensile stresses have to be considered. These mechanical loads favor wear in form of cracks and breaks at the cutting edge of the punch and thus decreasing tool life. In a special test rig these wear phenomena were observed in microblanking of copper foils. Although, high positioning accuracy between tools and workpiece can be assured within this test rig, scatter of tool life is observable. Therefore, a finite element (FE) analysis of the tool load in the microblanking process with special respect to tensile stresses was performed. Within the 3D FE model multidimensional positioning errors like tilting between punch and die were integrated. Their influence on the tool load in form of increasing tensile stresses is evaluated with respect to the type and magnitude of positioning error and verified by experimental results concerning wear. Furthermore, the effect of small outbreaks at the cutting edge on the process behavior and tool load is analyzed.
A Fourier Descriptor-Based Approach to Design Space Decomposition for Planar Motion Approximation
Authors: Li Xiangyun , Wu Jun , Ge Q. J.
Published: May 2016

In an earlier work, we have combined a curve fitting scheme with a type of shape descriptor, Fourier descriptor (FD), to develop a unified method to the synthesis of planar four-bar linkages for generation of both open and closed paths. In this paper, we aim to extend the approach to the synthesis of planar four-bar linkages for motion generation in an FD-based motion fitting scheme. Using FDs, a given motion is represented by two finite harmonic series, one for translational component of the motion and the other for rotational component. It is shown that there is a simple linear relationship between harmonic content of the rotational component and that of the translational component for a planar four-bar coupler motion. Furthermore, it is shown that the rotational component of the given motion identifies a subset of design parameters of a four-bar linkage including link ratios, while the translational component determines the rest of the design parameters such as locations of the fixed pivots. This leads naturally to a decomposed design space for four-bar mechanism synthesis for approximate motion generation.
A Proposed General Method of Stress Analysis for Tubesheet of Heat Exchanger
Authors: Zhu Hongsong , Zhai Jinguo , Wang Haifeng , Zheng Yixiang
Published: May 2016

The stress analysis method for fixed tubesheet (TS) heat exchangers (HEX) in pressure vessel codes such as ASME VIII-1, EN13445, and GB151 all assume a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the unit or one TS is need to be considered. In this study, the midplane symmetry assumption is discarded. More common situations are considered such as unequal TS thickness, different edge conditions, pressure drop, and dead weight on two TSs. Based on the classical thin plate and shell theoretical solution, an analytical method of stress analysis for TS is presented. The proposed method is suitable for different types of HEX due to fewer assumptions employed in this study. Analysis shows that floating and U-tube HEX are the two special cases of the proposed method. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the proposed method. Typical geometries and loading are considered, and the proposed method is used to check the adequacy of design. Predictions are compared with the results obtained from axisymmetric finite element analysis (FEA) and current ASME method. Comparison results indicate that predictions given by this paper agree well with FEA while ASME results are not correct or not accurate.
Residual Stress Distribution in a Dissimilar Weld Joint by Experimental and Simulation Study
Authors: Jiang Wenchun , Luo Yun , Li J. H. , Woo Wanchuck
Published: May 2016

Dissimilar welding between carbon steel and stainless steel is widely used in power plant. A lot of stress corrosion cracking (SCC) have occurred in the weld joint, which are affected greatly by residual stresses. This paper presents a study of residual stress in a dissimilar weld between 0Cr18Ni9 steel and 20 low carbon steel with Inconel 182 weld metal, by using neutron diffraction, X-ray diffraction measurement and finite-element method (FEM). The residual stresses show asymmetric distribution due to the dissimilar materials. The maximum longitudinal (1.92ReL304) and transverse stresses (1.07ReL304) are presented in the weld metal and heat effected zone of 20 carbon steel, respectively. Through the thickness of weld metal, the average longitudinal stress is around 370 MPa. The weld root has a stress concentration, and the stresses near the weld root in the 20 steel are larger than those in 0Cr18Ni9 steel, making the weld root become the most risk zone for SCC. With the increase of heat input, the residual stress and plastic deformation around the weld root increase. Hence, low heat input is recommended for the welding between 0Cr18Ni9 steel and 20 carbon steel.
Array Volume Fraction-Dependent Thermal Transport Properties of Vertically Aligned Carbon Nanotube Arrays
Authors: Zhao Yang , Chu Rong-Shiuan , Grigoropoulos Costas P. , Dubon Oscar D. , Majumdar Arun
Published: May 2016

Vertically aligned carbon nanotube (CNT) arrays are promising candidates for advanced thermal interface materials (TIMs) since they possess high mechanical compliance and high intrinsic thermal conductivity. However, the overall thermal performance of CNT arrays often falls short of expectations when used as TIMs, and the underlying reasons have yet to be fully understood. In this work, the volume fraction of CNT arrays is demonstrated to be the key factor in determining the CNT array thermal transport properties. By increasing the array volume fraction, both the CNT array effective thermal conductivity and the CNT array–glass thermal contact conductance were experimentally found to increase monotonically. One interesting phenomenon is that the increasing rate of thermal conductivity is larger than that of array volume fraction. Compressive experiments verified that the CNT arrays with lower volume fractions suffer from severe buckling, which results in a further decreasing trend. By understanding the underlying reasons behind this trend, the overall thermal performance of vertically aligned CNT arrays can be further increased.
Heat Transfer Inside the Physical Vapor Transport Reactor
Authors: Zhang Zeyi , Xu Min , Wang Liqiu
Published: May 2016

The physical vapor transport (PVT) method is widely adopted to produce semiconductor materials including silicon carbide (SiC). This work focuses on the role of thermal radiation for the heat transfer inside the PVT reactor. The radiation is characterized by two dimensionless parameters relating to the SiC charge and to the growth chamber. A simulation program is set up with the finite-volume method (FVM), considering heat generation, conduction, and radiation under the steady-state condition. Comprehensive results are obtained by tuning values of dimensionless parameters and the associated controlling variables, such as the cooling temperature and the coil current density, and illustrated in the phase diagrams. From the study, we find that the charge size has negligible influence on the temperature field, the crucible conduction determines the temperature level, and the relative strength of the chamber radiation against the crucible conduction modifies the temperature field on the SiC ingot. Finally, design guidelines are proposed with the instructive phase diagram to achieve the optimized thermal performance of the PVT reactor.
Sound transmission loss of double plates with an air cavity between them in a rigid duct
Authors: Kim Hyun-Sil , Kim Sang-Ryul , Lee Seong-Hyun , Seo Yun-Ho , Ma Pyung-Sik
Published: May 2016

In this paper, the sound transmission loss (STL) of thin double plates with an air cavity between them in a rigid duct is considered using an analytical approach. The vibration motion of the plate and sound pressure field are expanded in terms of an infinite series of the modal functions. Under the plane wave condition, a low frequency solution is derived by including the first few symmetric modes. It is determined that the peak frequencies of the double plates coincide with those of each single plate. When the two plates are identical, the STL becomes zero at the natural frequencies of the single plate. However, when the two plates are not identical, the STL is always greater than zero. The location and amplitude of the dips are investigated using an approximate solution when the cavity depth is very small. It is observed that dividing the single plate into two plates with an air cavity in between degrades the STL in the low frequency range, while the equivalent surface mass density is preserved. However, when the cavity depth is not small, the STL of the single plate can be smaller than that of the double plates.
Sparse feature learning for instrument identification: Effects of sampling and pooling methods
Authors: Han Yoonchang , Lee Subin , Nam Juhan , Lee Kyogu
Published: May 2016

Feature learning for music applications has recently received considerable attention from many researchers. This paper reports on the sparse feature learning algorithm for musical instrument identification, and in particular, focuses on the effects of the frame sampling techniques for dictionary learning and the pooling methods for feature aggregation. To this end, two frame sampling techniques are examined that are fixed and proportional random sampling. Furthermore, the effect of using onset frame was analyzed for both of proposed sampling methods. Regarding summarization of the feature activation, a standard deviation pooling method is used and compared with the commonly used max- and average-pooling techniques. Using more than 47 000 recordings of 24 instruments from various performers, playing styles, and dynamics, a number of tuning parameters are experimented including the analysis frame size, the dictionary size, and the type of frequency scaling as well as the different sampling and pooling methods. The results show that the combination of proportional sampling and standard deviation pooling achieve the best overall performance of 95.62% while the optimal parameter set varies among the instrument classes.
Evaluation of the successive approximations method for acoustic streaming numerical simulations
Authors: Catarino S. O. , Minas G. , Miranda J. M.
Published: May 2016

This work evaluates the successive approximations method commonly used to predict acoustic streaming by comparing it with a direct method. The successive approximations method solves both the acoustic wave propagation and acoustic streaming by solving the first and second order Navier-Stokes equations, ignoring the first order convective effects. This method was applied to acoustic streaming in a 2D domain and the results were compared with results from the direct simulation of the Navier-Stokes equations. The velocity results showed qualitative agreement between both methods, which indicates that the successive approximations method can describe the formation of flows with recirculation. However, a large quantitative deviation was observed between the two methods. Further analysis showed that the successive approximation method solution is sensitive to the initial flow field. The direct method showed that the instantaneous flow field changes significantly due to reflections and wave interference. It was also found that convective effects contribute significantly to the wave propagation pattern. These effects must be taken into account when solving the acoustic streaming problems, since it affects the global flow. By adequately calculating the initial condition for first order step, the acoustic streaming prediction by the successive approximations method can be improved significantly.