bluuebunny/crossref_metadata_2025 huggingface dataset:
Yes, we can: physical activity and group identification among healthy adults
Authors: Grant Fiona , Hogg Michael A. , Crano William D.
Published: March 2015

Drawing on social identity theory and social cognitive theory, this research was designed to investigate the role played by group identification, self‐efficacy and outcome expectations in physical activity behavior. Healthy adult participants (N = 130) who identified strongly with an exercise referent group reported higher levels of physical activity, and this relationship was mediated by self‐efficacy and outcome expectations. This study adds to the existing literature on the effects of social groups on health and is one of the first to examine the interplay of personal factors and group membership on physical activity.
Characteristics of Systemic Hypertension in Preterm Children
Authors: Shah Ankur B. , Hashmi S. Sharukh , Sahulee Raj , Pannu Hariyadarshi , Gupta‐Malhotra Monesha
Published: March 2015

The prevalence of essential hypertension (EH) among preterm children is unknown. The authors evaluated consecutive children with a diagnosis of hypertension and prematurity (gestational age <37 weeks) in a tertiary pediatric hypertension clinic and identified 36 preterm hypertensive children. Among these preterm children, 23 were diagnosed in the neonatal intensive care unit (NICU; infantile) and 13 were diagnosed at an older age (childhood). When compared with patients with a childhood diagnosis, patients with an infantile diagnosis had a significantly lower gestational age, longer duration of hospitalization in the NICU, and a higher incidence of perinatal risk factors for hypertension. None with infantile diagnosis had EH, whereas 46% with childhood diagnosis had EH. Among premature children, systemic hypertension was either diagnosed in infancy or in childhood, with each age at diagnosis having unique risk factors and clinical course. Although 83% of preterm children had secondary hypertension, EH was diagnosed in 17% and was only seen in those diagnosed beyond infancy.
Distribution of intestinal metaplasia as a predictor of gastric cancer development
Authors: Shichijo Satoki , Hirata Yoshihiro , Sakitani Kosuke , Yamamoto Shinzo , Serizawa Takako , Niikura Ryota , Watabe Hirotsugu , Yoshida Shuntaro , Yamada Atsuo , Yamaji Yutaka , Ushiku Tetsuo , Fukayama Masashi , Koike Kazuhiko
Published: March 2015

Background and Aim

Helicobacter pylori, gastritis, and intestinal metaplasia (IM) are known risk factors for gastric cancer. In the present study, we conducted a cohort study to evaluate the predictive value of the distribution of IM for gastric cancer development.

Methods

We conducted a retrospective cohort study at a university hospital. From June 1998 to December 2000, we assessed histological gastritis using biopsy specimens, one from the antrum and one from the corpus, from 1450 patients, among whom 729 revisited for follow‐up endoscopy. Patients were classified into three groups according to the distribution of IM at initial endoscopy. IM group A had no IM, IM group B had IM in the antrum only, and IM group C had IM in the corpus. The development of gastric cancer was assessed by endoscopic examination.

Results

The mean duration of follow‐up was 6.7 ± 4.7 years. The cumulative incidence of gastric cancer at 5 years was 1.5% in total and 0.8%, 3.3%, and 2.7% in IM groups A, B, and C, respectively. The IM group was identified as an independent risk factor by multivariate analysis; compared with IM group A, hazard ratios were 3.6 (95% confidence interval [CI] 1.1–12.1) in IM group B and 3.8 (95% CI 1.01–14.1) in IM group C. In IM group C, the incidence of gastric cancer in patients who received eradication therapy was significantly lower than that in patients who did not receive (P = 0.021, log‐rank).

Conclusion

IM is a good predictive marker for the development of gastric cancer.
Appearance of hepatobiliary diseases in a population‐based cohort with inflammatory bowel diseases (Inflammatory Bowel Disease Cohort of the Uppsala Region)
Authors: Rönnblom Anders , Holmström Tommy , Tanghöj Hans , Rorsman Fredrik , Sjöberg Daniel
Published: March 2015

Background and Aim

To prospectively follow the evolution of hepatobiliary diseases in a population‐based cohort of patients with inflammatory bowel diseases.

Methods

Between 2005 and 2009, 790 incident cases of ulcerative colitis and Crohn's disease were registered in the Uppsala Health Region, corresponding to an average incidence of 20.0 and 9.9 new cases/100 000 inhabitants/year, respectively. Liver function tests were analyzed in 97.1% and the results of ensuing investigations were summarized.

Results

Seventeen patients with primary sclerosing cholangitis were diagnosed corresponding to an overall prevalence of 2.2% (ulcerative colitis 1.7% and Crohn's disease 3.0%, respectively). The median age at diagnosis was 25 years (interquartile range: 17.0–34.0). Among the 92 patients below 17 years of age, three had autoimmune hepatitis and three primary sclerosing cholangitis, summing up to a prevalence of 6.5% immune‐mediated hepatobiliary diseases among the pediatric patients. Three patients have undergone liver transplantation and one died of colonic carcinoma. Ten patients have demonstrated persistent elevation of alkaline phosphatases but had a normal magnetic resonance cholangiopancreatography (two patients) or refused further investigation (one patient).

Conclusion

In this first large prospective population‐based cohort of 526 patients with ulcerative colitis (UC) and 264 with Crohn's disease, 17 cases of primary sclerosing cholangitis were found, among whom three (17%) so far have been liver transplanted and one has died of colon carcinoma. The average age of those affected by primary sclerosing cholangitis is considerably lower than usually reported. Ten patients had or have had elevated alkaline phosphatase without confirmed liver or biliary disease.
Adverse pregnancy outcome in patients with low pregnancy‐associated plasma protein‐A: The Indian Experience
Authors: Gupta Sangeeta , Goyal Manisha , Verma Deepti , Sharma Anjana , Bharadwaj Namita , Kabra Madhulika , Kapoor Seema
Published: March 2015

Aim

The aim of our study was to examine the association of low pregnancy‐associated plasma protein‐A (PAPP‐A) with adverse pregnancy outcome.

Material and Methods

A total of 1640 consecutive pregnant women between 9+5 and 13+6 weeks of pregnancy were recruited. One hundred and thirty women with PAPP‐A levels < 0.4 multiple of median were followed till delivery and the outcome information was obtained for fetal loss, birthweight, growth restriction, preterm birth, reduced liquor and development of pre‐eclampsia.

Results

During the study period, 130 (7.92%) women had low PAPP‐A and were considered as cases and 200 women with normal PAPP‐A were controls. Intrauterine growth restriction was observed in 28 (21.54%) cases as compared to 10 (5%) controls. Pre‐eclampsia presented in 24 (18.46%) cases and in 18 (9%) controls. Twenty (15.38%) cases had preterm delivery compared to 12 (6%) controls. Fifty‐six (43.08%) cases delivered low‐birthweight babies compared to 22 (11%) controls. Thus, the incidence of intrauterine growth restriction, preterm birth and low birthweight was significantly more in the cases as compared to the control group.

Conclusions

PAPP‐A is a valuable analyte for predicting risk of adverse pregnancy outcome and women with low serum PAPP‐A levels would benefit from closer surveillance.
Opsoclonus–ataxia syndrome associated with ovarian mature teratoma
Authors: Kanno Kiyoshi , Kin Syogo , Hirose Masaki , Suzuki Satoshi , Watanabe Takafumi , Fujimori Keiya
Published: March 2015

A 16‐year‐old girl with no prior medical history developed vertigo and nausea following alimentary infection. Neurological examination showed limb and truncal ataxia, opsoclonus, myoclonus, and hyperreflexia. Brain magnetic resonance imaging and cerebrospinal fluid analysis showed no abnormalities. Treatment with i.v. high‐dose methylprednisolone and immunoglobulin was started, but this proved ineffective. The clinical course was unusual, so whole‐body computed tomography was done to evaluate other differential diagnoses. Imaging identified right ovarian mature teratoma. Paraneoplastic opsoclonus–ataxia syndrome was suspected, therefore single‐incision laparoscopic ovarian cystectomy was done 10 days after admission. Two months after therapy, the patient had complete recovery and remained asymptomatic at 1 year after onset. Serum testing for anti‐neuronal antibodies was negative, including for anti‐N‐methyl‐d‐aspartate‐receptor antibody. Young women with ataxia and opsoclonus of unclear etiology should be examined for the presence of ovarian teratoma, then intensive immunotherapy and prompt tumor resection can lead to good clinical outcome.
Getting “Bi” in the Family: Bisexual People's Disclosure Experiences
Authors: Scherrer Kristin S. , Kazyak Emily , Schmitz Rachel
Published: March 2015

There are many similarities in gay, lesbian, and bisexual individuals' coming out experiences, but bisexual people face unique challenges. Despite this, an explicit focus on bisexual people is missing from family research. Using family systems and cultural sociological perspectives, the authors analyzed how social and cultural factors shape disclosure processes for bisexuals as they come out to multiple family members. After analyzing qualitative data from a diverse group of 45 individuals, they found that bisexual people navigate monosexist and heterosexist expectations in their family relationships. Cultural constructions of bisexuality shape the ways that bisexual people disclose their identities, including how they use language to influence family members' responses in desirable ways. Relationship status also influences bisexual people's disclosure strategies, as a romantic partner's gender is meaningful to family members' understandings of their sexual orientation. The findings highlight the importance of addressing cultural and social contexts in understanding sexual minority people's coming out processes.
Applicability of the Foodtexture Puff Device for Rheological Characterization of Viscous Food Products
Authors: Morren Sofie , Van Dyck Tim , Mathijs Frank , Luca Stijn , Cardinaels Ruth , Moldenaers Paula , De Ketelaere Bart , Claes Johan
Published: March 2015

The Foodtexture Puff Device (FPD) is a noncontact rheological measurement device, which applies an air pulse on the sample and measures the subsequent deformation of the sample surface with a laser distance sensor. The deformation behavior is considered as a measure for the rheological properties of the sample. The applicability of this device was studied for use on viscous food products with a broad range of rheological characteristics. In this study, sugar and fat‐based systems with a viscosity range of respectively 0.001–6.1 Pa.s and 0.01–5.9 Pa.s were tested. Comparison of the FPD with classical rheological analyses showed that the maximum deformation created by the FPD is strongly correlated to the viscosity. Hence, the FPD is well suited for measurements on sugar‐based and fat‐based systems. It is capable of providing accurate, noncontact, fast, easy and nondestructive rheological measurements on food products.

Practical Applications

The FPD is a new, noncontact rheological measurement device that can be used for a wide range of food products, including sugar solutions, fruit purees and concentrates, oils and fats, molten chocolate, batter, soft pastry, among others. Furthermore, more solid food products like dough can be measured accurately. The device outputs a displacement signal over time from which information can be extracted. For simple behaviors, this can be performed based on one or a few characteristic values derived from the signal. For more complex foodstuff, the signal as a whole can be used, and techniques such as partial least squares can be used to create a calibration curve that translates the full displacement signal over time into the desired rheological values. Seen the fact that measurement time is short, the FPD is suitable for in‐line as well as for R&D applications and can replace classical devices that are often time consuming and require sample preparation.
Introgressive hybridization: brown bears as vectors for polar bear alleles
Authors: Hailer Frank
Published: March 2015

The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male‐biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture‐free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach.
Involvement of reductases IruO and NtrA in iron acquisition by Staphylococcus aureus
Authors: Hannauer Mélissa , Arifin Andrew J. , Heinrichs David E.
Published: March 2015

To obtain host iron, Staphylococcus aureus secretes siderophores staphyloferrin A (SA) or staphyloferrin B (SB), and accesses heme iron through use of iron‐regulated surface determinant proteins. While iron transport in S. aureus is well documented, there is scant information about proteins required to access iron from complexes in the cytoplasm. In vitro studies identified a pyridine nucleotide‐disulfide oxidoreductase, named IruO, as an electron donor for the heme monooxygenases IsdG and IsdI, promoting heme degradation. Here, we show that an iruO mutant was not debilitated for growth on heme, suggesting involvement of another reductase. NtrA is an iron‐regulated nitroreductase and, as with the iruO mutant, a ntrA mutant grew on heme comparable with wild type (WT). In contrast, a iruO ntrA double mutant was severely debilitated for growth on heme, a phenotype that was complemented by expression of either iruO or ntrA in trans, demonstrating their overlapping role in heme‐iron utilization. Contrasting the involvement of multiple reductases for heme iron utilization, ntrA was shown essential for iron utilization using SA, although not SB or other siderophores tested, and an iruO mutant was incapable of deferoxamine‐mediated growth. Accordingly, virulence of WT S. aureus, but not an iruO mutant, was enhanced in mice receiving deferoxamine.
Albuminuria and reduced glomerular filtration rate for predicting the renal outcomes in type 2 diabetic patients
Authors: Tanaka Nobue , Babazono Tetsuya , Takagi Michino , Yoshida Naoshi , Toya Kiwako , Nyumura Izumi , Hanai Ko , Uchigata Yasuko
Published: March 2015

Aim

The first clinical manifestation of diabetic kidney disease is usually the development of microalbuminuria. However, recent studies have focused on diabetic patients with reduced glomerular filtration rate (GFR) without albuminuria. To evaluate the association of albuminuria and GFR with renal outcomes, we performed an observational study.

Methods

A total of 3231 type 2 diabetic patients were included in this study between 2003 and 2005. There were 1249 women and the mean age was 59 ± 12 years. The renal endpoints were defined as the initiation of renal replacement therapy (RRT) or 50% reduction from the baseline of estimated GFR (eGFR).

Results

At baseline, 669 (20.7%) patients had eGFR <60 mL/min per 1.73 m2 and 1134 (35.1%) had albuminuria. During the mean follow‐up period of 5.9 ± 1.6 years, 107 patients initiated RRT. A 50% reduction of eGFR from the baseline value was found in 279 patients. None of the normoalbuminuric subjects with or without reduced eGFR required RRT during the observational period (P < 0.01). Compared to normoalbuminuria patients with eGFR ≥60 mL/min per 1.73 m2 at baseline, the group of normoalbuminuria patients with reduced eGFR had a 2.5‐fold risk of developing the renal endpoints, (95% confidence interval (CI): 1.0–6.3, P = 0.053). Patients with microalbuminuria with eGFR ≥60 mL/min per 1.73 m2 at baseline had a 5.0‐fold risk of developing the evaluated renal endpoints (95% CI: 2.8–8.8, P < 0.001).

Conclusion

Albuminuria was a significant predictor for the evaluated renal endpoints, but the impact of eGFR is likely to be less than that of albuminuria.
Dental core trainee teaching of dental students in a clinical setting: a pilot study
Authors: Finn D.J. , Taylor K.H. , Balmer M.C.
Published: March 2015

Aim

This study aims to gain opinions from both dental core trainees and undergraduate dental students in relation to dental core trainees undertaking a clinical teacher role when supervising undergraduate students in a clinical setting.

Materials and methods

Forty‐five undergraduate students completed a written questionnaire following a clinic being supervised by dental core trainees to provide feedback on their experience. A focus group was held with 12 dental core trainees to ascertain their thoughts and feeling in relation to supervising undergraduate students.

Results

Undergraduates appeared to give positive feedback and found dental core trainees to be approachable and provided adequate feedback. However, areas of improvement were identified by students in relation to their grading and in providing feedback on performance. Dental core trainees enjoyed their teaching experience, though a range of concerns were highlighted in relation to this.

Conclusions

This study demonstrated that undergraduates and dental core trainees were satisfied with the educational experience. Areas for improvement were demonstrated in training of the grading scheme used and in assessment of students' knowledge.
Innovation audits by means of formulating problems
Authors: Björkdahl Joakim , Holmén Magnus
Published: March 2015

Prior innovation audits consist of scorecards that firms use to assess their innovation processes and capabilities. The multifaceted nature of innovation means that this approach does not contextualize the audit for the audited firms. This paper proposes an innovation audit method that identifies and formulates valuable innovation‐related problems. It comprises four sequentially dependent modules which follow a structured process that allows the firm's innovation processes and capabilities to be audited. The audit was developed based on performing innovation audits with five multinational companies in the manufacturing and hygiene sectors, and nine pulp and paper companies. The paper discusses the pros and cons of different innovation audits. We suggest that the innovation audit process may be a means for changing a firm's strategic innovation orientation, and contribute to the development of innovation capabilities.
The Value of Transferable Skills
Authors: Sgobbi Francesca , Suleman Fátima
Published: March 2015

Most studies on skill transferability focus on the return to capabilities developed in the initial job and disregard the different characteristics of the origin and the destination industries. In contrast, this article assesses the borders of skill transferability by comparing the return to skills for firm stayers, firm changers in the same industry, and firm changers to other industries. Based on a sample of Portuguese employees in retail banking, our results confirm significant inter‐firm and inter‐industry skill transferability. Difference‐in‐differences estimates with propensity score matching show that firm switchers benefit from a wage premium compared to firm stayers. However, the wage premium drops sharply when movers leave the banking sector.
Power in the Field. Explaining the Legitimisation of Large‐Scale Farming in Romania
Authors: Roger Antoine
Published: March 2015

Examining the development of Romanian agriculture, one may wonder how a few large‐scale agribusinesses have managed to legitimise their position and to deflect open criticism even as they control a disproportionate share of arable land. Clarification may be provided by Pierre Bourdieu's concept of field, which involves the simultaneous characterisation of sets of objective positions and symbolic struggles over the definition of hierarchical principles. This analytical framework allows us to shed light on the economic field and its relationships with other fields, which each have their own structure and are each influenced by specific struggles. Large‐scale agricultural holdings in Romania find support within the political and the scientific fields, each of which provides supports within the bureaucratic field. The coincidence of different fields prevents any questioning of the economic model on which the development of large‐scale farming is based.
Estimating Geographical PV Potential Using LiDAR Data for Buildings in Downtown San Francisco
Authors: Li Ziqi , Zhang Zidong , Davey Keith
Published: March 2015

Sustainable solar energy is of the interest for the city of San Francisco to meet their renewable energy initiative. Buildings in the downtown area are expected to have great photovoltaic (PV) potential for future solar panel installation. This study presents a comprehensive method for estimating geographical PV potential using remote sensed LiDAR data for buildings in downtown San Francisco. LiDAR derived DSMs and DTMs were able to generate high quality building footprints using the object‐oriented classification method. The GRASS built‐in solar irradiation model (r.sun) was used to simulate and compute PV yields. Monthly and yearly maps, as well as an exquisite 3D city building model, were created to visualize the variability of solar irradiation across the study area. Results showed that monthly sum of solar irradiation followed a one‐year cycle with the peak in July and troughs in January and December. The mean yearly sum of solar irradiation for the buildings in the study area was estimated to be 1675 kWh/m2. A multiple regression model was used to test the significance of building height, roof area and roof complexity against PV potential. Roof complexity was found to be the dominant determinant. Uncertainties of the research are mainly from the inherent r.sun limitations, boundary problems, and the LiDAR data accuracy in terms of both building footprint extraction and 3D modeling. Future work can focus on a more automated process and segment rooftops of buildings to achieve more accurate estimation of PV potential. The outcome of this research can assist decision makers in San Francisco to visualize building PV potential, and further select ideal places to install PV systems. The methodology presented and tested in this research can also be generalized to other cities in order to meet contemporary society's need for renewable energy.
The impact of human immunodeficiency virus infection on obstetric hemorrhage and blood transfusion in South Africa
Authors: Bloch Evan M. , Crookes Robert L. , Hull Jennifer , Fawcus Sue , Gangaram Rajesh , Anthony John , Ingram Charlotte , Ngcobo Solomuzi , Croxford Julie , Creel Darryl V. , Murphy Edward L. ,   for the International Component of the NHLBI Recipient Epidemiology and Donor Evaluation Study‐III (REDS‐III)
Published: March 2015

BACKGROUND

Globally, as in South Africa, obstetric hemorrhage (OH) remains a leading cause of maternal mortality and morbidity. Although blood transfusion is critical to OH management, the incidence and predictors of transfusion as well as their relation to human immunodeficiency virus (HIV) infection are poorly described.

STUDY DESIGN AND METHODS

A cross‐sectional study was conducted of all peripartum patients at four major hospitals in South Africa (April to July 2012). Comprehensive clinical data were collected on patients who sustained OH and/or were transfused. Logistic regression was used to model risk factors for OH and transfusion.

RESULTS

A total of 15,725 peripartum women were evaluated, of whom 3969 (25.2%) were HIV positive. Overall, 387 (2.5%) women sustained OH and 438 (2.8%) received transfusions, including 213 (1.4%) women with both OH and transfusion. There was no significant difference in OH incidence between HIV‐positive (2.8%) and HIV‐negative (2.3%) patients (adjusted odds ratio [OR], 0.95; 95% confidence interval [CI], 0.72‐1.25). In contrast, the incidence of blood transfusion was significantly higher in HIV‐positive (3.7%) than in HIV‐negative (2.4%) patients (adjusted OR, 1.52; 95% CI, 1.14‐2.03). Other risk factors for transfusion included OH, low prenatal hemoglobin, the treating hospital, lack of prenatal care, and gestational age of not more than 34 weeks.

CONCLUSION

In the South African obstetric setting, the incidence of peripartum blood transfusion is significantly higher than in the United States and other high‐income countries while OH incidence is similar. While OH and prenatal anemia are major predictors of transfusion, HIV infection is a common and independent contributing factor.
A benchmarking program to reduce red blood cell outdating: implementation, evaluation, and a conceptual framework
Authors: Barty Rebecca L. , Gagliardi Kathleen , Owens Wendy , Lauzon Deborah , Scheuermann Sheena , Liu Yang , Wang Grace , Pai Menaka , Heddle Nancy M.
Published: March 2015

BACKGROUND

Benchmarking is a quality improvement tool that compares an organization's performance to that of its peers for selected indicators, to improve practice.

STUDY DESIGN AND METHODS

Processes to develop evidence‐based benchmarks for red blood cell (RBC) outdating in Ontario hospitals, based on RBC hospital disposition data from Canadian Blood Services, have been previously reported. These benchmarks were implemented in 160 hospitals provincewide with a multifaceted approach, which included hospital education, inventory management tools and resources, summaries of best practice recommendations, recognition of high‐performing sites, and audit tools on the Transfusion Ontario website (http://transfusionontario.org). In this study we describe the implementation process and the impact of the benchmarking program on RBC outdating. A conceptual framework for continuous quality improvement of a benchmarking program was also developed.

RESULTS

The RBC outdating rate for all hospitals trended downward continuously from April 2006 to February 2012, irrespective of hospitals' transfusion rates or their distance from the blood supplier. The highest annual outdating rate was 2.82%, at the beginning of the observation period. Each year brought further reductions, with a nadir outdating rate of 1.02% achieved in 2011. The key elements of the successful benchmarking strategy included dynamic targets, a comprehensive and evidence‐based implementation strategy, ongoing information sharing, and a robust data system to track information.

CONCLUSION

The Ontario benchmarking program for RBC outdating resulted in continuous and sustained quality improvement. Our conceptual iterative framework for benchmarking provides a guide for institutions implementing a benchmarking program.
Pattern Analysis of IDEO's Human-Centered Design Methods in Developing Regions
Authors: Fuge Mark , Agogino Alice
Published: March 2015

While there is increasing interest in designing for the developing world, identifying appropriate design research methods for understanding user needs and preferences in these unfamiliar contexts is a major challenge. This paper demonstrates how to apply a variety of statistical techniques to an online design case study repository, Human-Centered Design (HCD) Connect, to discover what types of methods designers use for identifying user needs and preferences for developing-world problems. Specifically, it uncovers how the following factors correlate to method usage: application area (e.g., farming versus healthcare), affiliation of the person using the method (IDEO designer versus not), and stages of the user research process. It finds that designers systematically use certain types of methods for certain types of problems, and that certain methods complement each other in practice. When compared with non-IDEO users, professional designers at IDEO use fewer methods per case and focus on earlier stages of the process that involve data gathering. The results demonstrate the power of combining data-driven statistical techniques with design case studies to identify user research methods for different developing-world problems, as well as locating which research methods complement each other. It also highlights that professionals designing for developing-world contexts commit more time to earlier stage user research efforts, rather than in concept generation or delivery, to better understand differences in needs and design contexts.
Effective Mechanical Properties of Carbon-Carbon Composites
Authors: Sudhir Aswathi , Nagaraja Abhilash M. , Gururaja Suhasini
Published: March 2015

In recent times, composite materials have gained mainstream acceptance as a structural material of choice due to their tailorability and improved thermal, specific strength/stiffness and durability performance [1–3]. For high temperature applications, which include exit nozzle for rockets, leading edge for missiles, nose cones, brake pads etc. Carbon-Carbon composites (C/C composite) are found suitable [4–6]. Mechanical property estimation of C/C composites is challenging due to their highly heterogeneous microstructure. The highly heterogeneous microstructure consists of woven C-fibers, C-matrix, irregularly shaped voids, cracks and other inclusions. Predicting the mechanical behavior of complex hierarchical materials like C/C composites is of interest which forms the motivation for the present work. A systematic study to predict the effective mechanical properties of C/C composite using numerical homogenization has been undertaken in this work. The Micro-Meso-Macro (MMM) principle of ensemble averages for estimating the effective properties of the composite has been adopted. The hierarchical length scales in C/C composites were identified as micro (single fiber with matrix), meso (fabric) and macro (laminate). Comparisons have been made with mechanical testing of C/C composites at different length scales.
Influence of Hard Turning on Microstructure Evolution in the Subsurface Layers of Inconel 718
Authors: Touazine H. , Jahazi M. , Bocher P.
Published: March 2015

This study investigated the effects of semi finish, finish and critical finish machining parameters on the microstructural evolution of subsurface layers in Inconel 718. In order to assess the microstructural evolution in the subsurface layer following machining, advanced characterization methods including opto-digital microscopy, X-ray diffraction and nanoindentation were used. Results showed that friction between the tool and the workpiece during machining lead to microstructural changes such as hardness enhancement on the surface, and softening on the subsurface. It was also observed that damage in the machined surface is related to the presence of defects such as cracks, cavities and carbide detachment from the surface. Finally, residual stress measurements revealed that, within the investigated parameters, the cutting speed has the most significant effect on surface integrity.
Development of CAM System for 3D Surface Machining With CNC Lathe (Tool Path Generation Considering Acceleration)
Authors: Takasugi Keigo , Nakagaki Katsuhiro , Morimoto Yoshitaka , Kaneko Yoshiyuki
Published: March 2015

This study developed a method called non-axisymmetric curved surface turning (NACS-Turning) for a CNC lathe composed of a turning axis and two translation axes. The NACS-Turning method controls the three axes synchronously. This new machining method can reduce the lead time for non-circular shapes such as cam profiles or pistons for internal combustion engines. In our previous report, we presented an outline of a machining principle and a CAM system for NACS-Turning. However, at the same time, we found the problem that the X-axis slide exceeds the allowable acceleration. Therefore, it is preferable that the acceleration is verified during the cam application, and the tool path is generated within the allowable acceleration range. Therefore, this paper first describes the determination method of machinable conditions for NACS-Turning in the cam application. Next, based on the result, relationships between the acceleration of the X-axis slide and machining conditions are clarified. Finally, the experimental procedure showed that our proposed method does not exceed the allowable acceleration of the X-axis slide.
Functional Prototyping and Tooling of FDM Additive Manufactured Parts
Authors: Rayegani Farzad , Onwubolu Godfrey C. , Nagy Attila , Singh Hargurdeep
Published: March 2015

In this paper, we present two additive manufacturing applications: (1) vacuum forming tooling using AM; (2) rocket functional prototype using AM for computational fluid dynamics (CFD) and wind-tunnel testing. The first application shows how additive manufacturing (AM) facilitates the manufacture of vacuum formed parts, which allows such parts to be easily produced especially in the manufacturing sector. We show how combining the advantages of the CAD and FDM technology, vacuum forming can be completed quickly, efficiently and cost effectively. The paper shows that using modified build parameters, the tools FDM creates can be inherently porous, which eliminates the time needed for drilling vent holes that are necessary for other vacuum forming tools, while improving part quality with an evenly distributed vacuum draw. Using SolidWorks CAD software, the model of the tool is created. The STL file is exported to the Insight software, and we present how the Tool Paths Custom Group feature is applied to optimize the tool-paths file and then sent to the FDM system that prints the tooling from ABS engineering thermoplastic. The tooling is then used in the Formech 686 manual vacuum forming machine to produce the vacuum formed part.

The second application shows how additive manufacturing (AM) has been applied to producing functional model for wind–tunnel testing, as well as providing computational fluid dynamics (CFD) tool for comparing results obtained from the wind-tunnel testing. The present work is focused on applications of FDM technology for manufacturing wind tunnel test models. The CAD model of a rocket was analyzed for its aerodynamic properties and its functional prototype produced using AM for use in wind–tunnel testing so as to verify and tune the aerodynamic properties. Initial wall conditions were defined for the rocket in terms of the air velocity. The flow simulation was carried out and the goals examined are the velocity and pressure fields around the rocket model. The paper examines some practical issues that arise between how the model geometry for CDF process differs from that that of the FDM process.

Consequently, we show that AM-based fused deposition modeling (FDM) technology is faster, less expensive and more efficient than traditional manufacturing processes for vacuum forming and for rapid prototyping of function models for wind-tunnel applications.
Taylor’s Model Based Analysis of Turning Inserts Tool-Life in the Dry Turning of UNS R56400 Alloy
Authors: Batista Moises , Davim Paulo , Salguero Jorge , Gomez-Parra Alvaro , Marcos Mariano
Published: March 2015

In this work a study of tool life of uncoated WC-Co inserts — utilized in the dry turning of Ti6A14V (UNS R56400) alloy — has been achieved. This study has been developed on the basis of the tool wear time monitoring as a function of cutting speed (V) for fixed feed (f) and cutting depth (d). Tool life (T) has been evaluated through the flank wear (VB) measurement, making use of ISO 3685 standard.

VB (T,V) surfaces have allowed defining the cutting speed range where T is maximum. On the other hand T(V) curves have allowed establishing the influence of cutting speed on tool life. From these curves a potential model, in the way of Taylor’s model, has been proposed.
Experimental and Numerical Analysis of Mechanical Behavior in Friction Stir Welded Different Titanium Alloys
Authors: Kulkarni Neha , Ramulu M.
Published: March 2015

Friction Stir Welding (FSW) has been widely accepted technique to join titanium alloy, Ti-6Al-4V, to produce defect free sheets of it. The friction stir welding with other titanium alloys has a potential to improve the utilization and functional properties of titanium. The current study was undertaken to evaluate the performance of friction stir welded (FSW) different titanium joints. The impact of process parameters, mainly the spindle speed and feed rate on the strength of friction stir welded titanium alloy joints was studied. A combined approach of numerical and experimental was used to investigate the mechanical response of different titanium joints. This paper presents the numerical model that was developed to simulate mechanical behavior of FSW titanium joints. The numerical results were compared to experimentally determined behavior characteristics of the joints to gage the validity of the modeling approach. It was found that there was good agreement in the numerical and experimental results of the tensile behavior in titanium FSW joints. The optimum values of spindle speed and feed rate were found out for joining different titanium alloys.
Analysis of Welded Joint Under Residual Stresses
Authors: Jawale H. P. , Singh Rahul
Published: March 2015

Welded joint is most commonly used for building structures and machine components. Welding process involves heating followed by uneven cooling causing residual stress field. In conjunction with stresses due to external loads, in-service behaviour is affected due to residual stress in welded components. It induces defects, also alters crack initiation life, fatigue behaviour, breaking strength, corrosion resistance and increases the susceptibility of structure to failure by fracture. The residual stress is function of cooling rate and the size of weld. The role of residual stress associated with welding is therefore very important while designing mechanical parts. Conventional methods like heat treatment and shot-peening techniques becomes difficult to be applied for reduction of residual stress in general purpose applications. The work presented in this paper describes the measurement of residual stress using stress relieving method, based on hole-drilling technique. Subsequently, residual stresses are relived and measured using strain rosette near the weld zone. These strains value is converted in to stress value. Residual stress is quantified with respect to yield strength, making it possible to be considered for safe designing of weld components.
Graphene Thin Films on Fiber-Reinforced Epoxy Composites for Improved Fire Retardancy
Authors: Le L. N. , Zhang B. , Asmatulu R.
Published: March 2015

Because of the high strength-to-weight and stiffness-to-weight ratios, the fiber-reinforced epoxy composites are the most common materials for many industrial applications. Nevertheless, these engineered materials can lose their properties when subjected to the high moisture, UV light and temperatures through oxidation and other decomposition processes. In order to minimize the weakness of the epoxy composites, graphene thin films were fabricated after the acid treatment process, and then applied onto the surface of fiber reinforced epoxy composites to act as heat shields. The 45 degree burn tests and surface paint adhesion tests were conducted on the prepared samples in accordance with the guidelines of the FAA Regulations, ASTM, SAE, and AMS specifications. The test results revealed significant improvements on the flame retardancy of the composites by incorporating graphene oxide thin films. Overall, this study may improve the fire resistance properties of the composites for different high temperature applications of composites.
Additive Manufacturing of Nitinol Shape Memory Alloys to Overcome Challenges in Conventional Nitinol Fabrication
Authors: Walker Jason , Andani Mohsen Taheri , Haberland Christoph , Elahinia Mohammad
Published: March 2015

The pseudoelastic and shape memory effects of NiTi can be used in passive or active actuation systems. Often used in the aerospace industry, the use of NiTi for actuation is also growing in the biomedical fields and elsewhere. However, it’s potential in industry is currently limited by the inability to produce complex NiTi parts. Conventional manufacturing processes are complicated by the extreme difficulty associated with machining NiTi. Furthermore, the transformation temperatures which drive the unique behavior of NiTi as a shape memory alloy are extremely sensitive to the relative concentrations of nickel and titanium. Therefore, exceptionally tight compositional control during production is necessary to guarantee ideal material behavior. Additive manufacturing (AM) is a near-net-shaping technology which allows for the direct fabrication of complex metallic components. By utilizing the AM processing principle, the poor machinability of NiTi is no longer an issue. Using AM also enables production of 3D geometries that are not possible using traditional techniques. Furthermore, direct CAD fabrication reduces the timescale of the concept-to-prototype transition. In the present work, an SLM machine (Phenix Systems PXM) is used to develop NiTi components directly from powder. The thermal characteristics and shape memory functionality of SLM NiTi components is demonstrated.
Serpent Beings, Sacrificial Brides, Superboy Saviors: Comparative Analysis of African Serpent Lore
Authors: Shanafelt Robert
Published: March 2015

Serpent lore, dragon lore, and related ritual have long been of interest in religious studies, anthropology, and folklore. While works that provide rich ethnographic descriptions of particular cultural contexts are not to be neglected, broader comparative studies are also of value. Here a comparative approach is taken to the investigation of two themes widespread in African cosmic serpent lore: a shape-shifting Serpent Being with dragon-like features who is master controller of the waters and a related myth of a superboy who saves the world by slaying a dragon monster. Comparative analysis of tales from Lesotho indicates that Sotho-Tswana people retained ancient ideas common to other peoples in south and central Africa, and beyond. These two story lines are interpreted in terms of debates about diffusion, common origins, and independent invention. Both cognitive naturalism and inter-societal contact, in different ways, offer explanation of these shared themes.
Direct measurement and modeling of the redirected ion flux in a high-powered pulsed-plasma magnetron
Authors: Meng Liang , Yu He , Sporre John R. , Raman Priya , Szott Matthew M. , McLain Jake T. , Ruzic David N.
Published: March 2015

Self-sputtering is a crucial feature in high-powered pulsed magnetron sputtering (HPPMS). A direct measurement of the recirculating ion fluxes to the target, however, has not been made until now using a specially designed magnetron system. A small orifice was drilled in the target, allowing plasma fluxes to penetrate and be diagnosed subsequently. Ion currents of the penetrating copper ions (Cu+) and argon ions (Ar+) were collected on biased grids, while Cu depositions were measured on witness Si wafers. Based on these measurements, fluxes of Cu+ ions and Ar+ ions were differentiated. For a tested condition, the ratio of Cu+ density to Ar+ density was determined to be 1.5 ± 0.3, indicating a strong self-sputtering effect during HPPMS. Using a semiempirical plasma model, this ratio was predicted to be 1.4 within plasma, matching well with the measurement. The model calculates the evolution of various plasma species in the strong ionization region and thus allows a quick estimation of some key HPPMS parameters such as Cu+ ionization fraction and Cu+ to Ar+ density ratio in a time-resolved manner. The ion currents were observed to increase abruptly after a certain time delay, longer for a lower pulse voltage. This suggests a mechanism that the plasma is only ignited initially in a stripe along the sputtering “racetrack” where the magnetic field (B) is strong enough. At a higher pulse voltage, the ignition plasma stripe became longer and drifted faster parallel to the target toward the region of weak magnetic field.
Analysis of biosurfaces by neutron reflectometry: From simple to complex interfaces
Authors: Junghans Ann , Watkins Erik B. , Barker Robert D. , Singh Saurabh , Waltman Mary Jo , Smith Hillary L. , Pocivavsek Luka , Majewski Jaroslaw
Published: March 2015

Because of its high sensitivity for light elements and the scattering contrast manipulation via isotopic substitutions, neutron reflectometry (NR) is an excellent tool for studying the structure of soft-condensed material. These materials include model biophysical systems as well as in situ living tissue at the solid–liquid interface. The penetrability of neutrons makes NR suitable for probing thin films with thicknesses of 5–5000 Å at various buried, for example, solid–liquid, interfaces [J. Daillant and A. Gibaud, Lect. Notes Phys. 770, 133 (2009); G. Fragneto-Cusani, J. Phys.: Condens. Matter 13, 4973 (2001); J. Penfold, Curr. Opin. Colloid Interface Sci. 7, 139 (2002)]. Over the past two decades, NR has evolved to become a key tool in the characterization of biological and biomimetic thin films. In the current report, the authors would like to highlight some of our recent accomplishments in utilizing NR to study highly complex systems, including in-situ experiments. Such studies will result in a much better understanding of complex biological problems, have significant medical impact by suggesting innovative treatment, and advance the development of highly functionalized biomimetic materials.
Improved surge protection of flip-chip gallium nitride-based HEMTs by metal-semiconductor-metal two-dimensional electron gas varactor
Authors: Tien Chu-Yeh , Kuei Ping-Yu , Chang Liann-Be
Published: March 2015

In this paper, the authors report on the development of aluminum gallium nitride/gallium nitride (AlGaN/GaN) high electron mobility transistors (HEMTs) with improved surge protection characteristics provided by a metal-semiconductor-metal two-dimensional electron gas (MSM-2DEG) varactor connected in series to the gate of each HEMT. Under an electrostatic discharge surge stress of 1100 V or less, HEMTs that incorporate this protection feature do not exhibit any changes because the surge stress is directly blocked by the MSM-2DEG varactor. In addition, flip-chip (FC) technology is also used to further improve the thermal performance and reliability of the HEMTs. The heat generated in the 2DEG channel of the HEMT flows directly through the interconnect metal to the submount, and hence, it improves thermal conduction. The results of experiments conducted show that the proposed FC HEMT with MSM-2DEG varactor has significantly improved surge protection characteristics.