bluuebunny/crossref_metadata_2025 huggingface dataset:
Partnership Transitions and Antisocial Behavior in Young Adulthood
Authors: Siennick Sonja E. , Staff Jeremy , Osgood D. Wayne , Schulenberg John E. , Bachman Jerald G. , VanEseltine Matthew
Published: April 2014

Objectives:

This study examines the effects of young adult transitions into marriage and cohabitation on criminal offending and substance use, and whether those effects changed since the 1970s, as marriage rates declined and cohabitation rates rose dramatically. It also examines whether any beneficial effects of cohabitation depend on marriage intentions.

Methods:

Using multi-cohort national panel data from the Monitoring the Future ( N = 15,875) study, the authors estimated fixed effects models relating within-person changes in marriage and cohabitation to changes in criminal offending and substance use.

Results:

Marriage predicts lower levels of criminal offending and substance use, but the effects of cohabitation are limited to substance use outcomes and to engaged cohabiters. There are no cohort differences in the associations of marriage and cohabitation with criminal offending, and no consistent cohort differences in their associations with substance use. There is little evidence of differences in effects by gender or parenthood.

Conclusions:

Young adults are increasingly likely to enter romantic partnership statuses that do not appear as effective in reducing antisocial behavior. Although cohabitation itself does not reduce antisocial behavior, engagement might. Future research should examine the mechanisms behind these effects, and why nonmarital partnerships reduce substance use and not crime.
What Are the Odds
Authors: Miller Byron
Published: April 2014

Previous studies find that romantic relationships adversely affect adolescents’ psychological well-being, yet none examine the differential effects of adolescent romance for same-race and interracial daters. Using data from the National Longitudinal Study of Adolescent Health (Add Health), I find that heterosexual adolescents in same-race relationships are more likely to be depressed than non-daters, but interracial daters have greater odds of risk for depression than their non-dating and same-race dating peers. Experiencing a romantic breakup explains the elevated risk of depression for daters in general, and same-race daters specifically, but not interracial daters. Furthermore, the associations that relationship status (dating vs. non-dating) and couple’s racial composition (same-race vs. interracial) have with depression are not moderated by race or gender. The findings highlight the differential effects of same-race and interracial romantic relationships on adolescent’s psychological well-being and the need to further examine the well-being of interracial daters.
Critical Subjects
Authors: Koskinen Inkeri
Published: April 2014

Participatory methods in anthropology and other fields of cultural research aim at turning informants into collaborators or co-authors. Researchers generally accept the idea of different knowledge systems and continue the practice of avoiding the critical appraisal of alien systems that is common in ethnography. However, if informants are to be treated as collaborators, or ideally as colleagues, they become effectively a part of the research community. Helen Longino has formulated criteria according to which the objectivity of research communities can be evaluated. These criteria rest heavily on the idea of effective peer criticism, and require appraisal of the reasoning and background assumptions of all members of the community. Avoiding the appraisal of alien knowledge systems is problematic when the alleged systems of the researcher and the researched are in constant contact.
Disassembling Actor-network Theory
Authors: Elder-Vass Dave
Published: April 2014

One of the strikingly iconoclastic features of actor-network theory is its juxtaposition of the claim to be a realist perspective with denials that supposedly natural phenomena existed before scientists “made them up.” This paper explains and criticizes such arguments in the work of Bruno Latour. By combining referent and reference in the concept of assemblages, Latour provides a superficially viable way to reconcile these apparently incompatible claims. This paper will argue, however, that this conflation of referent and reference leads Latour’s ontology into difficulties that can only be resolved by abandoning it in favor of a more conventional—critical—realism.
A unique case of facial burn superinfected with Dermatobia Hominis larvae resulting in a bilateral enucleation of the eyes
Authors: Pinos Victor Hugo , Ortiz-Prado Esteban , Bermeo Carlos , León Juan , Armijos Luciana , Almeida Estibaliz
Published: April 2014

We present a case of a female Ecuadorian patient who presented a deep facial burn injury complicated with a severe infestation of Dermatobia Hominis larvae. The burn injury was complicated by severe myiasis attributable to the poor management of the wound received at home, using tropical plants, which caused a secondary infection and severe necrosis of the tissue involving the forehead, cheeks, chin, scalp, nose, mouth and the eyes resulting in a bilateral enucleation and long inpatient hospital care.
The Eschatological Conversion of ‘All the Nations’ in Matthew 28.19-20: (Mis)reading Matthew through Paul
Authors: White Benjamin L.
Published: April 2014

The Great Commission in Matthew envisions the eschatological conversion of some from among ‘all the nations’ (πάντα τὰ ἔθνη) to Israel’s Messiah, Jesus of Nazareth, and to his authoritative interpretation of Torah, which, until the end arrives, includes the observance of its every ‘letter and stroke of a letter’. Matthew’s belief that foreigners will be converted to the Israelite covenant with YHWH at the ingathering of the lost sheep of the house of Israel coheres with other Second Temple Jewish texts and develops out of his reading of Isa. 56.1-8. Matthew is certainly unPauline in this regard, but he is not consciously anti-Pauline, as has been argued by David Sim. Yet, Matthew does advocate a position on Gentile inclusion into eschatological Israel that is fundamentally different from Paul’s. Matthew and Paul stand in canonical tension on the nature of Torah observance for Gentiles wanting to enter the ἐκκλησία of Israel.
Jesus as ‘The One who Entered his Rest’: The Christological Reading of Hebrews 4.10
Authors: Moore Nicholas J.
Published: April 2014

This article argues that in Heb. 4.10 the substantival aorist participle ὁ εἰσελθών should be translated ‘the one who entered’, and that its implied subject is Christ; it further suggests that, understood this way, this verse coheres with Hebrews’ strong emphasis on the completed nature of Christ’s salviﬁc work, expressed in particular with the image of Christ’s enthronement or session using Ps. 110.1. The article thus challenges the view that the rest motif in Heb. 3–4 is purely a ‘sermon illustration’ with no connection to the strong Christology pervading the rest of the letter; additionally it underscores the creativity with which the author expresses the sufﬁciency of the Christ event, and strengthens the proximity of the motifs of entering rest and entering the heavenly sanctuary.
Fashions, Fallacies and Future Prospects in New Testament Studies
Authors: Hurtado Larry W.
Published: April 2014

In New Testament studies, over the last century or so, there have been both ‘fashions’ (short-lived approaches) and ‘fallacies’ (approaches and ideas widely accepted for many years that later proved wrong), a few of which are reviewed here. With reference to these fallacies, especially, why did so many scholars entertain them, and what can we learn from them? As we look toward the future of the ﬁeld, what developments and emphases might we foresee as proving more than passing fashions?
The interaction between organizational justice and job characteristics: Associations with work attitudes and employee health cross-sectionally and over time
Authors: Eib Constanze , Bernhard-Oettel Claudia , Näswall Katharina , Sverke Magnus
Published: April 2014

The present study investigates to what extent main and interactive effects of overall organizational justice and job characteristics shape employees’ work attitudes (organizational commitment, intention to stay) and health (mental health, somatic health) cross-sectionally and after a period of one year. Questionnaire data from 429 Swedish accountants show that generally both organizational justice and job characteristics had main effects on all outcomes at both time points. Interactions between organizational justice and job characteristics were found for every job characteristic studied (demand, control, support), for both time points but mainly for intention to stay and somatic health. The results show that perceptions of organizational justice and job characteristics can have additive and multiplicative synergetic effects for work attitudes and employee health.
My Mother and Me
Authors: Fu Alyssa S. , Markus Hazel Rose
Published: April 2014

“Tiger Mother” Amy Chua provoked a culture clash with her claim that controlling parenting in Asian American (AA) contexts produces more successful children than permissive parenting in European American (EA) contexts. At the heart of this controversy is a difference in the normative models of self that guide behavior. Ideas and practices prevalent in AA contexts emphasize that the person is and should be interdependent with one’s close others, especially one’s mother. In contrast, EA contexts emphasize the person as independent, even from one’s mother. We find that AA compared with EA high school students experience more interdependence with their mothers and pressure from them, but that the pressure does not strain their relationship with their mothers. Furthermore, following failure, AAs compared with EAs are more motivated by their mothers, and AAs are particularly motivated by pressure from their mothers when it conveys interdependence.
Me After You
Authors: Slotter Erica B. , Emery Lydia F. , Luchies Laura B.
Published: April 2014

Individuals in ongoing romantic relationships incorporate attributes from their partner into their own self-concepts. However, little research has investigated what happens to these attributes should the relationship end. Across three studies, the present research sought to examine factors that predicted whether individuals retain or reject attributes from their self-concept that they initially gained during a relationship. We predicted that individuals would be more likely to reject attributes from their self post-dissolution if their ex-partner was influential in them adding those attributes to the self in the first place. However, we expected this effect to be moderated such that individuals who exerted greater, versus lesser, effort in maintaining relevant attributes would retain them as part of the self, regardless of whether the attribute originated from the partner. In addition, in two of our three studies, we explored the roles of partner influence, effort, and attribute rejection on individuals’ post-dissolution self-concept clarity.
Blogging while angry: the sustainability of emotional labor in the Asian American blogosphere
Authors: Lopez Lori Kido
Published: April 2014

The Asian American blogosphere has developed to encompass a variety of voices regularly providing readers with news items, opinions, and personal narratives of life in Asian America. In this article I investigate the relationship between emotion and activism in order to better understand the potential for using blogs as part of a sustainable social movement, as well as to theorize the kind of labor that activism can entail. This study is based on interviews with 15 bloggers who have created or written for blogs that focus specifically on Asian American issues. Through an analysis of the bloggers’ interviews and their blogging archive, I argue that emotion can play a foundational role in generating activist interventions and building the necessary community required for contributing to social change, but can also have a deleterious impact on the individuals involved. It is only through recognizing the ambivalent role of emotion within the affective labor of activism online that we can work toward more sustainable participation and impact.
The Varied Work of Challenger Movements: Identifying Challenger Roles in the US Environmental Movement
Authors: Bertels Stephanie , Hoffman Andrew J. , DeJordy Rich
Published: April 2014

Organizations within challenger movements often exhibit differences in what they do, with whom they interact, and how they understand or present themselves. This article attempts to understand what underlies such heterogeneity in challenger movements. Adopting a mixed method approach, we explore the heterogeneous nature of the work undertaken by institutional challengers in the US environmental movement. Drawing on the tools of social network analysis, we develop a method to identify a set of distinct social positions. Next, drawing upon qualitative data on identity and work from websites and interviews with senior managers in environmental non-governmental organizations, we identify configurations of social position, identity, and work that result in a distinct set of challenger roles. Our analysis reveals how identity and social position can both enable and constrain individual organizations within a challenger movement in terms of their ability to undertake different types of institutional work. We also identify a form of work thus far not explicitly identified in prior studies of institutional work–indirect work, which we theorize may be an important potential moderator to the effectiveness of direct forms of institutional work.
Taylorism, the International Labour Organization, and the Genesis and Diffusion of Codetermination
Authors: Nyland Chris , Bruce Kyle , Burns Prue
Published: April 2014

The conventional negative understanding of the scientific management movement has been challenged in recent decades by heterodox scholars who hold that the movement supported the democratization of the management process and in so doing worked closely with unions and with progressives within and around Roosevelt’s New Deal administration. This paper seeks to strengthen this challenge to orthodoxy by documenting how the leadership of the Taylor Society, a body established by Frederick Taylor’s inner circle as a vehicle to develop and promote their mentor’s ideas, strove to internationalize the diffusion of participatory management in tandem with the International Labour Organization, a body whose core purpose was and is to promote codetermination both in workplaces and in wider society.
Local Government Chief Executives’ Everyday Hauntings: Towards a Theory of Organizational Ghosts
Authors: Orr Kevin
Published: April 2014

This paper develops a theory of organizational ghosts, a concept that describes the haunted and burdensome aspects of organizational life and in particular of leadership action. The concept of organizational ghosts is not offered as yet another metaphor, a lens through which to analyse particular organizations. Rather, I offer my discussion of ghosts as a theoretical concept that explains how inheritances of the past haunt the relations and struggles of the present. I tell a ghostly tale of the everyday leadership and learning practices of UK local government chief executives, and provide an exploration of organizational ghosts as a contribution to the growing interest in the action in the shadows, atmospheres, margins and boundaries of organizations. Drawing upon an ethnographic study of UK local councils, and embracing the multiplicity and heterogeneity of organizational ghosts, the paper considers the theoretical, political and ethical stakes involved in taking ghosts seriously. Its contribution is to show how ghosts are insinuated in organizations and to highlight leaders as figures who are both willing agents and uneasy hosts of hauntings, and to point to the mediating role of leaders in handling confrontations between the past, the present and the future.
Making Sense of Misfortune
Authors: Hunzaker M. B. Fallin
Published: April 2014

One of the most striking features of stereotypes is their extreme durability. This study focuses on the role played by cultural schemas and perceptions of low-status others’ adversities in stereotype perpetuation. Social psychological theories of legitimacy and justice point to the role of stereotypes as one means through which individuals make sense of others’ undeserved misfortunes by redefining the victim. This study connects this work with insights from cognitive cultural sociology to propose that stereotypes act as cultural schemas used to justify others’ experiences of adversity. Consistent with this hypothesis, findings from a cultural transmission experiment show that participants include more negative stereotype-consistent content when retelling narratives with undeserved negative outcomes than with positive outcomes. Cognitive cultural sociology and the cultural transmission methodology offer tools for understanding victim redefinition processes, with important implications for the reproduction of stereotype bias and social inequalities.
Applying unidimensional and multidimensional item response theory models in testlet-based reading assessment
Authors: Min Shangchao , He Lianzhen
Published: April 2014

This study examined the relative effectiveness of the multidimensional bi-factor model and multidimensional testlet response theory (TRT) model in accommodating local dependence in testlet-based reading assessment with both dichotomously and polytomously scored items. The data used were 14,089 test-takers’ item-level responses to the testlet-based reading comprehension section of the Graduate School Entrance English Exam (GSEEE) in China administered in 2011. The results showed that although the bi-factor model was the best-fitting model, followed by the TRT model, and the unidimensional 2-parameter logistic/graded response (2PL/GR) model, the bi-factor model produced essentially the same results as the TRT model in terms of item parameter, person ability and standard error estimates. It was also found that the application of the unidimensional 2PL/GR model had a bigger impact on the item slope parameter estimates, person ability estimates, and standard errors of estimates than on the intercept parameter estimates. It is hoped that this study might help to guide test developers and users to choose the measurement model that best satisfies their needs based on available resources.
Movement disorders associated with spontaneous CSF leaks: A case series
Authors: Mokri Bahram
Published: April 2014

Importance and Objective

Headache is the most common symptom in spontaneous CSF leaks, frequently associated with additional manifestations. Herein, attention is drawn to movement disorder as a notable manifestation of spontaneous CSF leaks.

Design

Four women and one man (ages 51–78 years) with spontaneous CSF leaks and movement disorders were evaluated clinically and by pertinent neuroimaging studies with follow-up of one to seven years (mean 3.2 years).

Results

The movement disorder consisted of choreiform movements in two patients, torticollis in one, mixed tremor in one, and parkinsonism in one. All except the last patient had headaches (orthostatic in one, Valsalva maneuver-induced in one, both orthostatic and Valsalva-induced in two, lingering low-grade headache in one). Diffuse pachymeningeal enhancement and sinking of the brain was noted in all. CT-myelography showed definite CSF leak in three and equivocal leak in one, while no leak could be located in the fifth patient. Two patients improved over time with complete resolution of the movement disorder. One responded to epidural blood patch with complete resolution of his choreiform movements. Two patients required surgery and epidural blood patches. Results were drastic but nondurable in one, while complete recovery was achieved in the other.

Conclusion

Movement disorders are uncommon in spontaneous CSF leaks but occasionally can be one of the major components of the clinical presentation.
Thickening of the somatosensory cortex in migraine without aura
Authors: Kim Ji Hyun , Kim Jung Bin , Suh Sang-il , Seo Woo-Keun , Oh Kyungmi , Koh Seong-Beom
Published: April 2014

Objective

We aimed to explore cortical thickness abnormalities in a homogeneous group of patients with migraine without aura and to delineate possible relationships between cortical thickness changes and clinical variables.

Methods

Fifty-six female migraine patients without aura and T2-visible white matter hyperintensities and 34 female controls were scanned on a 3T magnetic resonance imager. Cortical thickness was estimated and compared between patients and controls using a whole-brain vertex-by-vertex analysis. Correlation analysis was conducted between cortical thickness of significant clusters and clinical variables.

Results

Compared to controls, migraine patients had cortical thickening in left rostral middle frontal gyrus and bilateral post-central gyri. Region-of-interest analysis revealed cortical thickening of bilateral post-central gyri in migraine patients relative to controls. The average thickness of bilateral post-central gyri positively correlated with disease duration as well as estimated lifetime headache frequency.

Conclusions

We have provided evidence for interictal cortical abnormalities of thickened prefrontal cortex and somatosensory cortex in female migraine patients without aura. Our findings of greater thickening of the somatosensory cortex in relation to increasing disease duration and increasing headache frequency suggest that repeated migraine attacks over time may lead to structural changes of the somatosensory cortex through increased noxious afferent input within the trigemino-thalamo-cortical pathway in migraine.
Age-Related Differences in Anterior Cruciate Ligament Remnant Vascular-Derived Cells
Authors: Uefuji Atsuo , Matsumoto Tomoyuki , Matsushita Takehiko , Ueha Takeshi , Zhang Shurong , Kurosaka Masahiro , Kuroda Ryosuke
Published: April 2014

Background:

The anterior cruciate ligament (ACL) does not heal spontaneously after injury, and patients of different ages respond differently to treatment. CD34+ stem/progenitor cells derived from the ACL remnant and associated tissues contribute to tendon-bone healing, but the relationship between age and the ACL’s healing potential has not been clarified.

Hypothesis:

The ACL remnant and associated tissues from adolescent patients have more CD34+ cells, and this population of cells from younger patients exhibits a higher potential for proliferation and differentiation in vitro.

Study Design:

Descriptive laboratory study.

Methods:

Ruptured ACL remnants and associated tissues were harvested from 28 patients (mean age, 24.6 ± 1.6 years) who had undergone primary arthroscopic ACL reconstruction. Patients were divided into 3 patient groups by age: 10-19 years (teens group; n = 10), 20-29 years (20s group; n = 10), and ≥30 years (30s group; n = 8). The ACL remnant cells were characterized using fluorescence-activated cell sorting (FACS). Expansion potential was evaluated using population doubling (PD), and multilineage differentiation potential was assessed and compared.

Results:

The FACS analysis showed numerous CD34+ cells in the teens group compared with the 30s group (mean, 25.4% ± 7.9% vs 16.9% ± 3.9%, respectively; P = .044). The PD results indicated that the teens group had a significantly higher expansion potential than the 30s group at passage 3 (mean, 3.3 ± 0.2 vs 2.8 ± 0.2, respectively; P = .039). Young ACL remnant cells had a higher potential for osteogenic differentiation according to alkaline phosphatase activity (teens group, 169.5 ± 37.9 × 10 ng/mL vs 30s group, 64.9 ± 14.6 × 10 ng/mL; P = .029) and osteocalcin gene expression (teens group, 1.0 ± 0.25 vs 30s group, 0.39 ± 0.01; P = .01). In addition, the teens group displayed a higher differentiation potential to angiogenic lineages (acetylated low-density lipoprotein/ Ulex europaeus lectin-stained cell counts) than other groups (teens group, 15.9 ± 1.9 vs 20s group, 8.9 ± 1.3 [ P = .04]; teens group, 15.9 ± 1.9 vs 30s group, 7.2 ± 1.5 [ P = .008]) and also tube length (teens group, 6939 ± 470 μm vs 30s group, 4119 ± 507 μm; P = .009).

Conclusion:

The ACL remnants of adolescent patients had more CD34+ cells, and those cells had a higher potential for proliferation and multilineage differentiation in vitro.

Clinical Relevance:

During remnant-preserving or remnant-transplanted ACL reconstruction, surgeons should consider the patient’s age when predicting the healing potential.
Quantifying measurement uncertainty in full-scale compost piles using organic micro-pollutant concentrations
Authors: Sadef Yumna , Poulsen Tjalfe G , Bester Kai
Published: April 2014

Reductions in measurement uncertainty for organic micro-pollutant concentrations in full scale compost piles using comprehensive sampling and allowing equilibration time before sampling were quantified. Results showed that both application of a comprehensive sampling procedure (involving sample crushing) and allowing one week of equilibration time before sampling reduces measurement uncertainty by about 50%. Results further showed that for measurements carried out on samples collected using a comprehensive procedure, measurement uncertainty was associated exclusively with the analytic methods applied. Application of statistical analyses confirmed that these results were significant at the 95% confidence level. Overall implications of these results are (1) that it is possible to eliminate uncertainty associated with material inhomogeneity and (2) that in order to reduce uncertainty, sampling procedure is very important early in the composting process but less so later in the process.
The Harm of Male-on-Female Rape
Authors: Kelland Lindsay
Published: April 2014

This article attacks David Benatar’s claim made in his 2012 book, The Second Sexism: Discrimination Against Men and Boys, that when an individual is the victim of violence it does not matter whether his or her perpetrator is of the same or a different sex. By exploring two related yet distinct phenomena, well documented in the empirical psychological literature, that I call “shattering” and “fragmentation,” I argue that when a woman is raped, it does matter that her rapist is male, given that her situation as a woman under patriarchy is partly constitutive of the harm that she suffers.
A numerical simulation of woven/anionic polyamide 6 composite part manufacturing using structural reactive injection moulding process
Authors: García-Manrique JA , Hoto R , Gascón Ll , Andrés J
Published: April 2014

In this work, a structural reactive injection moulding process using reactive anionic polyamide 6 (APA-6) is studied. Semi-empirical equations for the prediction of the APA-6 reaction kinetics and an advection equation for void transport are used in the numerical scheme. A complex numerical simulation of reactive injection of ε-caprolactam was developed for a three-dimensional industrial part. The validity of the approach is demonstrated for determining an effective injection strategy, including the position of vents and gates and the most effective parameter values for minimum mould filling time without the formation of voids.
Rheological and mechanical properties of polypropylene/calcium carbonate nanocomposites prepared from masterbatch
Authors: Chafidz Achmad , Kaavessina Mujtahid , Al-Zahrani Saeed , Al-Otaibi Mansour N
Published: April 2014

Polypropylene (PP)/calcium carbonate (CaCO3) nanocomposites were prepared from masterbatch by melt blending in a twin-screw extruder. The effect of three different nano-CaCO3 loadings (5, 10, and 15 wt%) on the rheological/viscoelastic and mechanical properties of the nanocomposites was investigated. A scanning electron microscopy was used to study the morphology of the nanocomposites, whereas a differential scanning calorimetry was used to analyze the thermal properties. The rheological properties were characterized using an oscillatory rheometer, and the mechanical properties were characterized by a tensile test machine. In the melt rheological study, a frequency sweep test showed that the complex viscosity [Formula: see text], the storage modulus ( G′), and the loss modulus ( G″) of the nanocomposites increased with nano-CaCO3 loading. The increase in [Formula: see text] was approximately 1.4–1.9 times greater than that of the PP matrix. Shear-thinning behavior was also observed for the nanocomposite samples. Additionally, the relaxation time spectrum and the relaxation modulus, G( t), were determined by fitting experimental data ( G′ and G″) using the Maxwell element method via numerical analysis. The results showed that the time required for stress relaxation of the nanocomposites was longer than that of the matrix. In the solid viscoelastic study, dynamic mechanical thermal analysis results showed that the G′ value of the nanocomposites increased by approximately 15–25% compared with that of neat PP. The tensile test results showed an improvement in the tensile modulus and toughness (especially at 10 and 15 wt%), while the tensile strength showed a moderate decrease. On the other hand, the incorporation of nano-CaCO3 in the PP matrix has enhanced the overall flexural and Izod impact properties of the nanocomposites.
Application of chiral diacid N-trimellitylimido-l-valine for the surface modification of copper oxide as inorganic filler and preparation of poly(amide–imide)/cupric oxide nanocomposites
Authors: Mallakpour Shadpour , Vahabi Maryam
Published: April 2014

In this study, the thermally stable poly(amide–imide) (PAI)/cupric oxide (CuO) nanocomposites (NCs) containing 4, 6 and 8 wt% of CuO nanoparticles (NPs) were prepared by ultrasonic technique. At first, the optically active PAI was synthesized from the polymerization of a chiral monomer, N-trimellitylimido-l-valine, with 4,4′-methylenebis(3-chloro-2,6-diethylaniline) in a green medium using molten tetra- n-butylammonium bromide and triphenyl phosphite. Then, in order to prevent agglomeration of NPs and to obtain high compatibility between the NPs and the polymer matrix, the surface of the CuO NPs was successfully modified using a bioactive diacid containing l-valine amino acid. Finally, PAI/CuO NCs were produced via sonochemical reaction. The resulting NCs were characterized by means of Fourier transform infrared spectra, x-ray diffraction, thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy techniques. FE-SEM results showed that the CuO NPs were homogeneously dispersed in the PAI matrix without agglomeration for NC 4 wt%. However, with increasing in the percentage of CuO NPs, some aggregations were observed. The TGA curves indicated that the obtained PAI/CuO NCs are thermally more stable than the pure PAI. The shielding ability of modified CuO NPs and PAI/CuO NCs was also investigated by ultraviolet–visible spectroscopy.
Wear behavior of γ-irradiated ultra high-molecular weight polyethylene in a hip joint simulator
Authors: Mohamad Raffi N , Kanagarajan D , Srinivasan V
Published: April 2014

In this work, the wear behavior of cross-linked ultra-high-molecular weight polyethylene (UHMWPE) is discussed. The UHMWPE specimens are molded through injection molding techniques by varying the parameters of melting temperature (MT). The cross linking of UHMWPE was carried out by iridium 192 isotopes, where the specimen received 25 kGy energy. The wear tests were conducted on a hip joint simulator that was designed and fabricated in the laboratory. The contact loads are varied from 50 N to 100 N. The study revealed that MT has influenced the hardness and wear properties such as coefficient of friction and wear rate, respectively. γ-Irradiated UHMWPE has better wear and friction resistances than unirradiated UHMWPE. The worn out surfaces were examined with the help of scanning electron microscope, and it revealed the presence of wear mechanisms such as ironing, scratching, ploughing, plastic deformation, and fatigue wear.
Bionanocomposite materials from layered double hydroxide/N-trimellitylimido-l-isoleucine hybrid and poly(vinyl alcohol)
Authors: Mallakpour Shadpour , Dinari Mohammad
Published: April 2014

Nanocomposites (NCs) of poly(vinyl alcohol) (PVA) with chiral-modified magnesium–aluminum-layered double hydroxides (LDHs) were prepared by solution intercalation method. A novel chiral organomodified LDH was synthesized from the coprecipitation reaction of the aluminum (III) nitrate nonahydrate, magnesium (II) nitrate hexahydrate, and bioactive N-trimellitylimido-l-isoleucine amino acid in aqueous solution via simple, fast, and green method under ultrasound irradiation for the first time. The morphology and structure of the obtained material are examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), and field-emission SEM techniques. The TEM and XRD structure study revealed a coexistence of exfoliated and intercalated modified LDH in PVA matrix. The effects of modified LDH contents on the thermal property of PVA films were investigated by thermogravimetric analysis method, and the results show that by the addition of the modified LDH into the PVA causes an increase in the thermal decomposition temperatures of the novel NC materials.
Synthesis of high-performance polyaniline/graphene oxide nanocomposites
Authors: Lin Shun-Jia , Sun Hong-Juan , Peng Tong-Jiang , Jiang Linn-Hai
Published: April 2014

Nanocomposites based on polyaniline (PANI) and graphene oxide sheets (GOs) were synthesized via in situ polymerization in the presence of cetyltrimethylammonium bromide (CTAB). The morphology and structure of the nanocomposites were characterized by atomic force microscopy, scanning electron microscopy, x-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. It was found that CTAB helps to exfoliate GOs in organic solvent and increases its dispersion in PANI matrix. PANI molecules formed are of different microstructures and are deposited onto the surface of GOs via π–π stacking and hydrogen bonding. The results show that the electrical conductivity and specific capacitance of PANI/GOs nanocomposites are strongly affected by the microstructure of PANI, which are originally induced by the presence of GOs and CTAB.
Preparation, characterization, and flame retardance of high-density polyethylene/sulfur-free expandable graphite composites
Authors: Li Kuo-Yi , Kuan Chen-Feng , Kuan Hsu-Chiang , Chen Chia-Hsun , Liu Tai-Ying , Chiang Chin-Lung
Published: April 2014

In this work, a hydrothermal method was used to prepare a novel, sulfur-free expandable graphite (EG), which was added to high-density polyethylene (HDPE) to improve the flammability and the dripping behavior of composites. Phosphoric acid (H3PO4) was utilized as the intercalating agent, and potassium permanganate and nitric acid were used as the oxidizing agent. EG was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry, energy dispersive spectrometry, and scanning electron microscopy. Thermogravimetric analysis, the limiting oxygen index (LOI) and UL-94 were used to examine the thermal and flame-retardant properties of the composites. The results demonstrated that the EG composite exhibited much better thermal stability than pure polymer. Additionally, at 30 wt% EG loading, the LOI value of HDPE/ EG fabrication by H3PO4-hydrothermal method (PEG) was 30, and the flammability standard of UL-94 reached the V0 level, verifying that the EG that was prepared using the H3PO4-hydrothermal process can effectively be used in fireproof composites. The tensile modulus of the composites increased with increasing filler content, while the tensile strength decreased. EG enhanced flexural strength and flexural modulus of HDPE composites but not with high EG loading. The impact strength of the composites was diminished due to the incorporation of EG into HDPE matrix.
Preparation of magnetic polyimide/maghemite nanocomposite fibers by electrospinning
Authors: Li Xue-Jia , Wei Qufu , Wang Xin
Published: April 2014

The polyimide (PI)/maghemite (γ-Fe2O3) nanocomposite fibers with magnetic behavior were prepared by electrospinning from polyamic acid/iron oxide (Fe3O4) solution, followed by thermal imidization process. The effect of Fe3O4 nanoparticles content in precursor mixture solution on the properties of PI/γ-Fe2O3 nanocomposite fibers was studied. The fibers were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The magnetic and mechanical properties of the electrospun PI/γ-Fe2O3 nanocomposite fibers were also investigated. The study showed that magnetic nanoparticles existed in the nanofibers in the form of physical composite, and with the increasing Fe3O4 content, the nanocomposite fibers became thinner, the break strength and elongation at break of the fiber membranes slightly decreased, and the saturation magnetization increased.
Tolerance range selection of topologically optimized structures with the effects of uncertainties of manufacturing process
Authors: Javed Arshad , Rout BK
Published: April 2014

Robust design methods for topology optimization have received significant attention from researchers in recent years. There are various attempts in past to handle the manufacturing uncertainty of the topologically optimized components. In the present work, same issue is dealt by introducing a method of probabilistic distribution of material. Here, help from Karhunen–Loeve expansion of stochastic process, coupled with Monte Carlo method is taken. The proposed method retains the uncertainty characteristic of the specific manufacturing processes such as etching, e-beam lithography, laser micro machining, and milling. Hence, this method offers larger flexibility to the designer. The simulation for manufacturing uncertainty is utilized to determine the optimal tolerance range of the factors for robust and targeted performance, which is almost nonexistent in the literature. The methodology for tolerance range selection is capable to incorporate uncertainty of multiple factors simultaneously. In this method cross array design of experiment approach is used to analyze the effect of tolerance of each factor. The overall process for manufacturing uncertainty and tolerance range selection is illustrated using four benchmark problems. The chosen factors for considered structural problems are force, elasticity, volume fraction, and aspect ratio. Various combinations of tolerance ranges are used to simulate the performance of the optimized structure, which is expressed in terms of robustness and targeted values of compliance, and maximum deflection. Based on the simulated results of signal-to-noise ratio and mean values of performance, the combinations of tolerance range are suggested that gives a high level of robustness or targeted performance accuracy. To indicate the uniqueness of proposed approach, the obtained response for performances is compared with already available response for performance in literature for generalized approach. Current work is advantageous compared to usual robust design, and provides the performance for a specific scenario at each possible combination of tolerance ranges.
Unified quantification of variation in passive knee joint constraint
Authors: Cyr Adam J , Maletsky Lorin P
Published: April 2014

The interrelationship that exists between multiple degrees of freedom to produce a net constraint across the range of passive motion of the knee is not fully understood. Manual joint laxity assessments were performed on 28 cadaveric specimens and used to develop a unified description of the passive laxity envelope that incorporated multiple degrees of freedom into a single analysis using radial basis functions. The unified envelopes were then included in a principal component analysis to identify the primary modes of variation. The first three modes of variation constituted 82% of the variation. The first principal component (36.5% explained variation) correlated with changes to the relationship between varus–valgus and internal–external rotation and had the largest impact on internal–external laxity. The second principal component (27.2% explained variation) correlated with a shift in the internal–external envelope. The third principal component (18.3% explained variation) correlated with a shift in the varus–valgus envelope and a change in varus–valgus laxity. This research presents a novel methodology for quantifying complex changes to passive knee constraint, which may be used as a means for objectively scoring joint laxity and evaluating complex relationships between degrees of freedom in a single analysis.
Assessing asymmetry using reflection and rotoinversion in biomedical engineering applications
Authors: Hill Shannon , Franco-Sepulveda Esteban , Komeili Amin , Trovato Alexandra , Parent Eric , Hill Doug , Lou Edmond , Adeeb Samer
Published: April 2014

Symmetry is a trait that has been extensively reviewed, especially clinically, as an indication of ideal geometry and health. Many geometric symmetry assessment techniques rely on two-dimensional measurements that do not account for the three-dimensional nature of the object. In this article, two methods, reflection and a process termed rotoinversion, a combination of reflection and rotation, are presented as potential methods to assess an object’s deviation from symmetry. With reflection, the geometric models are reflected about a calculated best plane of symmetry. With rotoinversion, the models are reflected about an arbitrary plane and then rigidly translated and rotated to best align the translated and original models. The methods give the same results for bilaterally symmetric objects, but different results for bilaterally and rotationally symmetric objects. The two methods are applied to assess asymmetry in adolescent idiopathic scoliosis torso geometric models, producing similar results. There was an angle of 0.408° between the normal to the plane of reflection from the reflection process and the normal from the rotoinversion process and average rotation of 0.067° from rotoinversion. The most appropriate method depends on the purpose of the symmetry assessment and must be determined on a case-by-case basis.
Chemosignalling, mechanotransduction and ciliary behaviour in the embryonic node: Computational evaluation of competing theories
Authors: Chen Duanduan , Norris Dominic , Ventikos Yiannis
Published: April 2014

Precise specification of left–right asymmetry is essential for patterning the internal organs of vertebrates. Within the embryonic node, posteriorly polarised cilia rotate, causing a leftward fluid flow (nodal flow) that establishes left–right asymmetry. The mechanism by which an embryo senses nodal flow remains uncertain. Existing hypotheses argue that either nodal flow carries morphogen(s) or lipid-bounded vesicles towards the left, thereby generating an asymmetric signal, and/or that mechano-sensory cilia sense this unidirectional flow, stimulating left-sided intracellular calcium signalling. To date, direct and definitive evidence supporting these hypotheses has been lacking. In this study, we conduct a multi-scale study to simulate the nodal cilia and the fluidic environment, analysing left–right signal transmission. By employing computational simulation techniques and solving the relevant three-dimensional unsteady transport equations, we study the flow pattern produced by the rotation of active cilia. By importing dilute species and particles into the computational domain, we investigate the transport of morphogens and nodal vesicular parcels, respectively. Furthermore, by extending the analysis to include the solid mechanics of passive deformable cilia and the coupling of their structural behaviour with the emerging fluid mechanics, we study the response of passive cilia to the nodal flow. Our results reproduce the unidirectional nodal flow, allowing us to evaluate the plausibility of both chemo- and mechano-sensing hypotheses. The quantitative measurements of the flow rate, the molecular transport and distribution provide guidance regarding the necessary morphogen molecular weights to break signalling symmetry. The passive sensory ciliary deformation gives indications regarding the plausibility of this mechano-signalling mechanism.
Stability and performance of pneumatic actuators in impedance control
Authors: Arbab Naser H , Najafi Farid
Published: April 2014

Investigating the ability of a pneumatic actuator to exhibit the desired mechanical impedance is the subject of this article. Inertia, stiffness and damping are three components of mechanical impedance, and achieving the desired values of these parameters is restricted. Inappropriate compensation of friction, low bandwidth or inaccurate measurement of the external force and losing the pressure tracking ability of the inner pressure control loop are the main factors that affect quality and range of achievable mechanical impedance in pneumatic actuators. In this article, the limitations induced by pressure tracking characteristics on the range of achievable mechanical impedance in pneumatic actuators are investigated by focusing on the inertia term. The experiments show that the minimum stable achievable target inertia in pneumatic actuators is limited; for low values of target inertia, the system goes toward instability. In this condition, the actuator shows sustained oscillations whose frequency and amplitude depend on the value of target inertia. Also, the value of minimum stable achievable target inertia is a function of actuator stiffness, so that for higher values of stiffness, the minimum stable achievable target inertia increases. In other words, the stability margin decreases. Then, on the basis of the results of the pressure tracking tests and taking into consideration the new mathematical model presented in this article, the experimental results are discussed.
Non-thromboembolic risk in systemic lupus erythematosus associated with antiphospholipid syndrome
Authors: Deák M , Bocskai M , Burcsár S , Dányi O , Fekete Z , Kovács L
Published: April 2014

Objectives

We investigated the impact of secondary antiphospholipid syndrome (APS) and antiphospholipid antibody (aPL) positivity on the non-thromboembolic clinical manifestations of systemic lupus erythematosus (SLE).

Methods

In total, 224 patients with SLE were studied, of whom 105 were aPL-positive; 52 fulfilled the criteria for APS. SLE- and APS-related clinical and laboratory features were assesed: SLE patients with aPL or APS were compared with those without these features.

Results

Not only thromboembolic events, but also Coombs-positive haemolytic anaemia, thrombocytopenia and endocarditis occurred significantly more frequently in the aPL-positive than in the aPL-negative patients. In the APS + SLE subgroup, several non-thromboembolic symptoms occurred more often than in the absence of APS: pleuritis, interstitial lung disease, myocarditis, nephritis and organic brain syndrome. The mean number of major organ manifestations (1.2 vs. 0.5) and the overall number of organ manifestations (8.1 vs. 6.9) were higher in the APS + SLE patients than in those without APS ( p < 0.05). The APS + SLE subgroup more frequently required intensive immunosuppressive treatment than did the APS-negative patients ( p < 0.05).

Conclusions

SLE patients with aPL positivity or secondary APS also have a higher risk to develop non-thromboembolic disease manifestations in addition to the aPL-related symptoms, and are predisposed to more severe SLE manifestations.