bluuebunny/crossref_metadata_2025 huggingface dataset:
Patients with chronic periodontitis present increased risk for osteoporosis: A population‐based cohort study in Taiwan
Authors: Mau L.‐P. , Kuan Y.‐C. , Tsai Y.‐W. C. , Lin J.‐J. , Huynh‐Ba G. , Weng P.‐W. , Shieh Y.‐S. , Cheng W.‐C. , Huang R.‐Y.
Published: May 2017

Objectives

Chronic periodontitis is a bone destructive inflammatory disease with an adverse impact on general health and suggested underlying factors in common with osteoporosis. A few studies have examined the possible relationship between chronic periodontitis and osteoporosis; however, the results remain inconclusive. This longitudinal follow‐up study investigated the possible risk of patients with chronic periodontitis to present osteoporosis by using a population‐based national health insurance data set in Taiwan.

Material and Methods

A random sample consisting of 1 million individuals was collected from Taiwan's national health insurance data set. From the sample, a total of 29 463 patients with newly diagnosed periodontitis from 2002 to 2008 were recruited and compared with a matched cohort of 58 926 patients without periodontitis. All patients were tracked until an osteoporosis diagnosis, or death, until the end of 2011. Associated factors, such as gender, age and comorbidities were examined. Cox proportional‐hazards regression was performed to examine the risk of osteoporosis for patients with or without periodontitis.

Results

Within the 6‐year follow‐up period, the incidence rates of osteoporosis in the periodontitis cohort and comparison group were 2.72 and 1.66 per 1000 person‐years, respectively. Mild, moderate and severe periodontitis were found to have 1.56, 2.09 and 2.08 times the risk of osteoporosis respectively compared to patients without periodontitis. Log‐rank analysis revealed that patients with periodontitis had significantly higher cumulative incidence rates of osteoporosis than the control group (P<.0001).

Conclusion

This study found that patients with periodontitis had a higher risk of being diagnosed with osteoporosis.
Inflorescence characteristics as function‐valued traits: Analysis of heritability and selection on architectural effects
Authors: Kulbaba Mason W. , Clocher Ilona C. , Harder Lawrence D.
Published: May 2017

Production of multiple flowers in inflorescences allows the reproductive phenotypes of individual plants to include systematic among‐flower variation, which could be adaptive. Systematic trait variation within inflorescences could arise from resource competition among flowers, or be a developmentally determined feature of flower position, regardless of resource dynamics. The latter, architectural effect typically manifests as continuous floral variation within inflorescences. For architectural effects to be adaptive, floral trait variation among individuals must covary with reproductive performance and be heritable. However, heritability and phenotypic selection on gradients of variation cannot be estimated readily with traditional statistical approaches. Instead, we advocate and illustrate the application of two functional data analysis techniques with observations of Delphinium glaucum (Ranunculaceae). To demonstrate the parameters‐as‐data approach we quantify heritability of variation in anthesis rate, as represented by the regression coefficient relating daily anthesis rate to inflorescence age. SNP‐based estimates detected significant heritability (h2 = 0.245) for declining anthesis rate within inflorescences. Functional regression was used to assess phenotypic selection on anthesis rate and a floral trait (lower sepal length). The approach used spline curves that characterize within‐inflorescence variation as functional predictors of a plant's fruit set. Selection on anthesis rate varied with inflorescence age and the duration of an individual's anthesis period. Lower sepal length experienced positive selection for basal and distal flowers, but negative selection for central flowers. These results illustrate the utility and power of functional‐data analyses for studying architectural effects and specifically demonstrate that these effects are subject to natural selection and hence adaptive.
Pathways of the association between maternal employment and weight status among women and children: Qualitative findings from Guatemala
Authors: Oddo Vanessa M. , Surkan Pamela J. , Hurley Kristen M. , Lowery Caitlin , de Ponce Silvia , Jones‐Smith Jessica C.
Published: May 2017

The double burden of malnutrition, defined by the coexistence of undernutrition and overweight, is well documented in low‐ and middle‐income countries. However, the mechanisms by which employment may be related to maternal and child weight status in low‐ and middle‐income countries are not well understood. We conducted in‐depth interviews among 20 mothers who participated in Project MIEL, a contemporary trial which evaluated the effects of an integrated micronutrient supplement and parenting intervention in rural Guatemala. We utilized semi‐structured interviews to explore the pathways by which maternal employment might influence bodyweight. Interviews were structured to explore the factors that mothers considered when deciding whether or not to participate in the labor force and how mothers perceived the influence of employment on determinants of their own bodyweight and that of their children. Themes were used to develop a conceptual framework. Mothers described four pathways through which employment could lead to changes in weight status: changes in food purchasing; improved household well‐being; changes in time allocation; and psychological effects. Mothers described purchasing increased quantities and more varied types of food, as well as the purchase of energy‐dense foods. Less time to devote to food preparation resulted in mothers preparing quicker meals and relying on substitute childcare. Mothers also expressed feelings of worry and neglect in relation to being employed, and perceived that these feelings would affect weight. A better understanding of these mechanisms is important for developing policies and programs to support women in the workplace and also reducing maternal and child overweight in Guatemala.
Symbiont strain is the main determinant of variation in Wolbachia‐mediated protection against viruses across Drosophila species
Authors: Martinez Julien , Tolosana Ignacio , Ok Suzan , Smith Sophie , Snoeck Kiana , Day Jonathan P. , Jiggins Francis M.
Published: May 2017

Wolbachia is a common heritable bacterial symbiont in insects. Its evolutionary success lies in the diverse phenotypic effects it has on its hosts coupled to its propensity to move between host species over evolutionary timescales. In a survey of natural host–symbiont associations in a range of Drosophila species, we found that 10 of 16 Wolbachia strains protected their hosts against viral infection. By moving Wolbachia strains between host species, we found that the symbiont genome had a much greater influence on the level of antiviral protection than the host genome. The reason for this was that the level of protection depended on the density of the symbiont in host tissues, and Wolbachia rather than the host‐controlled density. The finding that virus resistance and symbiont density are largely under the control of symbiont genes in this system has important implications both for the evolution of these traits and for public health programmes using Wolbachia to prevent mosquitoes from transmitting disease.
Bile salts and alkaline pHreciprocally modulate the interaction between the periplasmic domains ofVibrio choleraeToxRandToxS
Authors: Midgett Charles R. , Almagro‐Moreno Salvador , Pellegrini Maria , Taylor Ronald K. , Skorupski Karen , Kull F. Jon
Published: May 2017

ToxR is a transmembrane transcription factor that is essential for virulence gene expression and human colonization byVibrio cholerae. ToxR requires its operon partner ToxS, a periplasmic integral membrane protein, for full activity. These two proteins are thought to interact through their respective periplasmic domains, ToxRp and ToxSp. In addition, ToxR is thought to be responsive to various environmental cues, such as bile salts and alkaline pH, but how these factors influence ToxR is not yet understood. Using NMR and reciprocal pull down assays, we present the first direct evidence that ToxR and ToxS physically interact. Furthermore, using NMR and DSF, it was shown that the bile salts cholate and chenodeoxycholate interact with purified ToxRp and destabilize it. Surprisingly, bile salt destabilization of ToxRp enhanced the interaction between ToxRp and ToxSp. In contrast, alkaline pH, which is one of the factors that leads to ToxR proteolysis, decreased the interaction between ToxRp and ToxSp. Taken together, these data suggest a model whereby bile salts or other detergents destabilize ToxR, increasing its interaction with ToxS to promote full ToxR activity. Subsequently, asV. choleraealkalinizes its environment in late stationary phase, the interaction between the two proteins decreases, allowing ToxR proteolysis to proceed.
Neurokinin‐1 receptor blocker CP‐99 994 improved emesis induced by cisplatin via regulating the activity of gastric distention responsive neurons in the dorsal motor nucleus of vagus and enhancing gastric motility in rats
Authors: Sun X. , Xu L. , Guo F. , Luo W. , Gao S. , Luan X.
Published: May 2017

Background

Nowadays, chemotherapy induced nausea and vomiting (CINV) is still common in patients with cancer. It was reported that substance P mediated CINV via neurokinin‐1 (NK1) receptor and antagonists of NK1 receptor has been proved useful for treating CINV but the mechanism are not fully understood. This study aimed to examine the role of NK1 receptor blocker, CP‐99 994, when administrated into dorsal motor nucleus of vagus (DMNV), on the cisplatin‐induced emesis in rats and the possible mechanism.

Methods

Rats’ kaolin intake, food intake, and bodyweight were recorded every day; gastric contraction activity was recorded in conscious rats through a force transducer implanted into the stomach; gastric emptying was monitored using the phenol red method; single unit extracellular firing in the DMNV were recorded.

Key Results

DMNV microinjection of CP‐99 994 reduced the changes of increased kaolin consumption and suppressed food intake in cisplatin‐treated rats; enhanced the gastric contraction activity dose‐dependently in control and cisplatin‐treated rats but enhanced gastric emptying only in cisplatin‐treated rats; reduced the firing rate of gastric distention inhibited (GD‐I) neurons but increased the firing rate of GD excited (GD‐E) neurons in the DMNV. The effects of CP‐99 994 on gastric motility and neuronal activity were stronger in cisplatin‐treated rats than those of control rats.

Conclusions and Inferences

Our results suggested that CP‐99 994 could improve emesis induced by cisplatin by regulating gastric motility and gastric related neuronal activity in the DMNV.
Phenotype‐dependent selection underlies patterns of sorting across habitats: the case of stream‐fishes
Authors: Jacobson Bailey , Dubois Frédérique , Peres‐Neto Pedro R.
Published: May 2017

Spatial and temporal heterogeneity within landscapes influences the distribution and phenotypic diversity of individuals both within and across populations. Phenotype–habitat correlations arise either through phenotypes within an environment altering through the process of natural selection or plasticity, or phenotypes remaining constant but individuals altering their distribution across environments. The mechanisms of non‐random movement and phenotype‐dependent habitat choice may account for associations within highly heterogeneous systems, such as streams, where local adaptation may be negated, plasticity too costly and movement is particularly important. Despite growing attention, however, few empirical tests have yet to be conducted. Here we provide a test of phenotype‐dependent habitat choice and ask: 1) if individuals collected from a single habitat type continue to select original habitat; 2) if decisions are phenotype‐dependent and functionally related to habitat requirements; and 3) if phenotypic‐sorting continues despite increasing population density. To do so we both conducted experimental trials manipulating the density of four stream‐fish species collected from either a single riffle or pool and developed a game‐theoretical model exploring the influence of individuals’ growth rate, sampling and competitive abilities as well as interference on distribution across two habitats as a function of density. Our experimental trials show individuals selecting original versus alternative habitats differed in their morphologies, that morphologies were functionally related to habitat‐type swimming demands, and that phenotypic‐sorting remained significant (although decreased) as density increased. According to our model this only occurs when phenotypes have contrasting habitat preferences and only one phenotype disperses (i.e. selects alternatives) in response to density pressures. This supports our explanation that empirical habitat selection was due to a combination of collecting a fraction of mobile individuals with different habitat preferences and the exclusion of individuals via scramble competition at increased densities. Phenotype‐dependent habitat choice can thereby account for observed patterns of natural stream‐fish distribution.
Biodiversity–ecosystem function relationships change through primary succession
Authors: Mori Akira S. , Osono Takashi , Cornelissen J. Hans C. , Craine Joseph , Uchida Masaki
Published: May 2017

Ecologists traditionally use environmental parameters to predict successional shifts in compositional characteristics of local species assemblages (environmental control). Another important focus in ecology is to understand functional roles of species assemblages in determining local environmental properties (diversity control). Then, the question emerges: which is the cause, and which is the consequence? To clarify the causal relationships between species assemblages and environmental properties, we focused on seral changes in species/functional diversity of vascular plants in tundra ecosystems of the High Arctic. We found that, although species richness was influenced by soil properties in the earlier stages of primary succession, the causalities were reversed in the later stages. We also found functional differentiation among coexisting species in the later stage, suggesting that the ‘complementarity effect’ of diversity on ecosystem functions likely increased with ecosystem development through time. By contrast, particular species had little disproportional influence on soil properties, suggesting that the ‘selection effect’ as an alternative mechanism was less important. This result was likely attributed to the importance of facilitation in the marginal High Arctic environment. Plant–microsite associations are shaped by feedback mechanisms and therefore, neither plant nor microsite is a single absolute predictor of the other. Although our observational study has limitations, we demonstrates a possibility that the relative magnitude of the influence of one on the other can change in the process of succession, emphasizing that the causalities underlying biodiversity–ecosystem function relationships change through succession.
Commentary: Messy Business: Leading in Regeneration
Authors: Culhane Aidan
Published: May 2017

Related Content: Murphy et al. (PAR September/October 2017)
They are still the same – family members’ stories about their relatives with dementia disorders as residents in a nursing home
Authors: Cronfalk Berit Seiger , Norberg Astrid , Ternestedt Britt‐Marie
Published: May 2017

In order to better understand the context of suffering from dementia disorders, greater efforts should be made to understand and identify what persons with such disorders experience when living in a nursing home. The aim of this qualitative study was to gain further understanding of how persons with dementia disorders experienced and coped with their changed life situation after being relocated to a nursing home as described by their family members’ perceptions. Qualitative data were collected from ten interviews with family members and evaluated using content analysis. The main findings suggest that residents with dementia disorders largely maintained their personality intact throughout the trajectory of illness as they were able to keep their habits and interests. The local environment of the nursing home and the residents’ relationships to staff were important in order to feel accepted. Four categories were discerned during the analysis: living in limbo; coming to peace; keeping old habits and relationships; and thoughts about impending death. It is reasonable to believe that old habits and interests may be preserved as the embodiment of such habits are deeply rooted and connected to a person′s identity even when going through various changes and transitions in life. Therefore, to be accepted as the person you are requires care and services to specific needs, i.e. person‐centeredness. Lack of understanding from staff may therefore have an adverse effect on a person's self‐respect and identity. For that reason, staff needs to reflect on their attitudes and relationships as well as extending their knowledge about how to address sensitive topics such as the residents′ impending death. To achieve this support from managers is pivotal. Future research should focus on support to nursing staff to further knowledge and understanding about the individual changes resident go through near the end of life.
Beyond Continuity? Understanding Change in the UK Welfare State since 2010
Authors: McEnhill Libby , Taylor‐Gooby Peter
Published: May 2017

One approach to identifying policy change stresses policy instruments, settings and policy paradigms, while another also considers the process and culmination of various shifts and consequent outcomes. This article illustrates the debate through an examination of how far developments in social security policy between the 1997–2010 New Labour and 2010–15 Coalition Governments in the UK constituted real policy shifts. It shows that, despite continuities in instruments and approach, there have been substantial changes in the impact of welfare state policies related to short‐term benefits, employment and housing. The article identifies new policy directions leading to a different kind of welfare state, concerned less with living standards and equality and more with individual responsibility and paid work. It suggests that this has been achieved without the need for radical changes in instruments and their settings.
Reducing Inequality in Childcare Service Use across European Countries: What (if any) Is the role of Social Spending?
Authors: Van Lancker Wim
Published: May 2017

Childcare services are increasingly put forward as one of the most important policy levers to combat poverty and inequality. However, higher income families use childcare services to a much larger extent than lower income families. Almost all European countries increased expenditures on childcare over the past years, but has an ever‐increasing public spending on childcare provision led to more equality in its use? In this article, the relationship between spending and childcare use as well as between spending and inequality in childcare use over the period 2006–12 is empirically analyzed using a random effects model drawing on country‐level panel data (n = 156), derived from the EU‐SILC and OECD SOCX databases. Since governments can spend money in different ways, it is discussed whether a public or a market‐based strategy to subsidize childcare provision is related to more equality. The results suggest that more spending leads to higher levels of childcare use, but not directly to lower levels of inequality. For achieving equity in childcare use, government investment should lead to an expansion of childcare places across the income distribution. The findings allow the formulation of new hypotheses regarding the role of the private market in childcare services provision.
Changing Patterns of Uncontested Seats in Southern State Legislative Elections, 1984–2012*
Authors: Myers Adam S.
Published: May 2017

Objective

Despite the rise of two‐party politics in the American South, most state legislative elections in the region continue to feature only one major‐party candidate. I offer a new account of changes in partisan contestation of state legislative races in the region that centers on the growing importance of constituency partisanship over time.

Method

Using an original data set of district‐level presidential vote share between 1984 and 2012, I examine the changing effect of district partisanship on uncontestedness. I then estimate multivariate models predicting uncontested seats in 1988, 2000, and 2012.

Results

Between 1984 and 2012, the effect of incumbency on uncontestedness declines while the effect of partisanship rises.

Conclusion

The processes accounting for uncontested seats in southern legislative races have changed. Although uncontestedness in earlier periods was primarily driven by the incumbency advantage, in the contemporary period it is largely a result of the racially driven partisan sort of the southern electorate.
Identification of a novel HLA‐B allele, HLA‐B*08:177, in a Hungarian patient and her HLA identical sibling
Authors: Inotai D. , Illés Z. , Szabó E. , Varga Á. , Szilvási A.
Published: May 2017

The newly detected HLA‐B*08:177 differs from HLA‐B*08:01:01:01 by 1 single nucleotide substitution at position 365 of exon 3.
HENRY NELSON WIEMAN ON RELIGION AND REINHOLD NIEBUHR
Authors: Rice Daniel F.
Published: May 2017

Henry Nelson Wieman and Reinhold Niebuhr were theologically poles apart—Wieman a “new naturalist” and Niebuhr a “new super naturalist”—according to Wieman's nomenclature. Wieman devoted more time and attention to Niebuhr than Niebuhr did to him. The reason for this was the result of Wieman's sustained attack on the “new supernaturalism” with which he identified Niebuhr as one of the major American representatives. This article traces the background to Wieman's view of Niebuhr—Wieman's own views on science, on religion, and on Christianity—then proceeds to Wieman's analysis of Niebuhr's theology and his relation to the “new supernaturalism,” concluding with Niebuhr's reply to Wieman.
FURNISHING THE SKILL WHICH CAN SAVE THE CHILD: DIPHTHERIA, GERM THEORY, AND THEODICY
Authors: Johnson Kristin
Published: May 2017

Amid the diverse ways men and women have viewed the relationship between science and religion, explicit arguments that “Science is God's Provision” remain unexamined by historians. Such arguments are examined here as they relate to the problem of theodicy, by looking at a particular case study that inspired comments on the relationship between medicine and faith, namely, the discovery of the diphtheria antitoxin. This story highlights, first, the flexibility of the tradition of natural theology, and second, the important role the problem of theodicy has played in the history of the relationship between science and religion.
CURRENT HARMONICS MITIGATION FROM GRID CONNECTED VARIABLE SPEED WIND TURBINE DUE TO NONLINEAR LOADS USING SHUNT ACTIVE POWER FILTER
Authors: Qazi Sajid Hussain , Mustafa Mohd Wazir , Sultana U. , Hussain Mirjat Nayyar
Published: April 2017

The quality of power nowadays is of great concern due to increasing demand of supply and energy resources are limited, another cause is increasing penetration of nonlinear loads in the power system. In order to overcome energy supply challenges, the focus of technologists is shifting to the renewable energy side such as the wind and solar energy and so on. As such, mitigating effect of nonlinear loads have become ever important as well. In this context, various techniques have been used by researchers in past decades. Shunt active power filter (APF) have long been used to mitigate current harmonics from fixed wind turbine generator (WTG). In this study shunt APF has been applied with variable speed WTG using synchronous reference frame (SRF) for the extraction of compensation signal for APF. Gate driver signals are generated from Bang-Bang Controller (Hysteresis Band Current Controller HBCC). A MATLAB/SIMULINK based Model have been developed. The Simulation results show decreased THD levels of the system and clearly suggest the effectiveness of Shunt APF in meeting the IEEE-519 standard recommendation for harmonic levels in WTG.
OLTP PERFORMANCE IMPROVEMENT USING FILE-SYSTEMS LAYER COMPRESSION
Authors: Suharjito Suharjito , Kurnadi Adrianus B.
Published: April 2017

Database for Online Transaction Processing (OLTP) application is used by almost every corporations that has adopted computerisation to support their operational day to day business. Compression in the storage or file-systems layer has not been widely adopted for OLTP database because of the concern that it might decrease database performance. OLTP compression in the database layer is available commercially but it has a significant licence cost that reduces the cost saving of compression. In this research, transparent file-system compression with LZ4, LZJB and ZLE algorithm have been tested to improve performance of OLTP application. Using Swing-bench as the benchmark tool and Oracle database 12c, The result indicated that on OLTP workload, LZJB was the most optimal compression algorithm with performance improvement up to 49% and consistent reduction of maximum response time and CPU utilisation overhead, while LZ4 was the compression with the highest compression ratio and ZLE was the compression with the lowest CPU utilisation overhead. In terms of compression ratio, LZ4 can deliver the highest compression ratio which is 5.32, followed by LZJB, 4.92; and ZLE, 1.76. Furthermore, it is found that there is indeed a risk of reduced performance and/or an increase of maximum response time.
SIFAT MEKANIK DAN TINGKAH LAKU RESAPAN AIR BITUMEN TERUBAHSUAI GEOPOLIMER
Authors: Ibrahim Ahmad Nazrul Hakimi , Khairuddin Faridah Hanim , Md. Yusoff Nur Izzi , Borhan Muhamad Nazri , Mohd. Akhir Norliza
Published: April 2017

This study was conducted to investigate the mechanical properties and water absorption of geopolymer modified bitumen. Modification of 80/100 penetration grade bitumen with the 3, 5, 7 and 9% geopolymer (by weight of bitumen) were conducted using a melt blending technique. The study of mechanical properties of geopolymer modified bitumen was conducted using impact and hardness tests. On the other hand, water absorbed behaviour of bitumen was investigated using water absorption test. The results showed that the modification of base bitumen using geopolymer has increased the strength and hardness of binder up to 108% and 82% compared to the base bitumen. The absorption amount recorded by geopolymer modified bitumen can be considered as acceptable. This study found that 5% geopolymer is the optimum content of the modifier. Therefore, geopolymer can be considered as an alternative material to modify the mechanical properties of bitumen.
Mammalian target of rapamycin complex 2 regulates muscle glucose uptake during exercise in mice
Authors: Kleinert Maximilian , Parker Benjamin L. , Fritzen Andreas M. , Knudsen Jonas R. , Jensen Thomas E. , Kjøbsted Rasmus , Sylow Lykke , Ruegg Markus , James David E. , Richter Erik A.
Published: May 2017

Key points

Exercise is a potent physiological stimulus to clear blood glucose from the circulation into skeletal muscle.

The mammalian target of rapamycin complex 2 (mTORC2) is an important regulator of muscle glucose uptake in response to insulin stimulation.

Here we report for the first time that the activity of mTORC2 in mouse muscle increases during exercise.

We further show that glucose uptake during exercise is decreased in mouse muscle that lacks mTORC2 activity.

We also provide novel identifications of new mTORC2 substrates during exercise in mouse muscle.

Exercise increases glucose uptake into insulin‐resistant muscle. Thus, elucidating the exercise signalling network in muscle may uncover new therapeutic targets. The mammalian target of rapamycin complex 2 (mTORC2), a regulator of insulin‐controlled glucose uptake, has been reported to interact with ras‐related C3 botulinum toxin substrate 1 (Rac1), which plays a role in exercise‐induced glucose uptake in muscle. Therefore, we tested the hypothesis that mTORC2 activity is necessary for muscle glucose uptake during treadmill exercise. We used mice that specifically lack mTORC2 signalling in muscle by deletion of the obligatory mTORC2 component Rictor (Ric mKO). Running capacity and running‐induced changes in blood glucose, plasma lactate and muscle glycogen levels were similar in wild‐type (Ric WT) and Ric mKO mice. At rest, muscle glucose uptake was normal, but during running muscle glucose uptake was reduced by 40% in Ric mKO mice compared to Ric WT mice. Running increased muscle phosphorylated 5′ AMP‐activated protein kinase (AMPK) similarly in Ric WT and Ric mKO mice, and glucose transporter type 4 (GLUT4) and hexokinase II (HKII) protein expressions were also normal in Ric mKO muscle. The mTORC2 substrate, phosphorylated protein kinase C α (PKCα), and the mTORC2 activity readout, phosphorylated N‐myc downstream regulated 1 (NDRG1) protein increased with running in Ric WT mice, but were not altered by running in Ric mKO muscle. Quantitative phosphoproteomics uncovered several additional potential exercise‐dependent mTORC2 substrates, including contractile proteins, kinases, transcriptional regulators, actin cytoskeleton regulators and ion‐transport proteins. Our study suggests that mTORC2 is a component of the exercise signalling network that regulates muscle glucose uptake and we provide a resource of new potential members of the mTORC2 signalling network.
Evaluation of a Surrogate Contact Model in Force-Dependent Kinematic Simulations of Total Knee Replacement
Authors: Marra Marco A. , Andersen Michael S. , Damsgaard Michael , Koopman Bart F. J. M. , Janssen Dennis , Verdonschot Nico
Published: May 2017

Knowing the forces in the human body is of great clinical interest and musculoskeletal (MS) models are the most commonly used tool to estimate them in vivo. Unfortunately, the process of computing muscle, joint contact, and ligament forces simultaneously is computationally highly demanding. The goal of this study was to develop a fast surrogate model of the tibiofemoral (TF) contact in a total knee replacement (TKR) model and apply it to force-dependent kinematic (FDK) simulations of activities of daily living (ADLs). Multiple domains were populated with sample points from the reference TKR contact model, based on reference simulations and design-of-experiments. Artificial neural networks (ANN) learned the relationship between TF pose and loads from the medial and lateral sides of the TKR implant. Normal and right-turn gait, rising-from-a-chair, and a squat were simulated using both surrogate and reference contact models. Compared to the reference contact model, the surrogate contact model predicted TF forces with a root-mean-square error (RMSE) lower than 10 N and TF moments lower than 0.3 N·m over all simulated activities. Secondary knee kinematics were predicted with RMSE lower than 0.2 mm and 0.2 deg. Simulations that used the surrogate contact model ran on average three times faster than those using the reference model, allowing the simulation of a full gait cycle in 4.5 min. This modeling approach proved fast and accurate enough to perform extensive parametric analyses, such as simulating subject-specific variations and surgical-related factors in TKR.
Secure Collaboration in Engineering Systems Design
Authors: Wang Shumiao , Bhandari Siddharth , Chaitanya Chaduvula Siva , Atallah Mikhail J. , Panchal Jitesh H. , Ramani Karthik
Published: May 2017

The goal in this paper is to enable collaboration in the codesign of engineering artifacts when participants are reluctant to share their design-related confidential and proprietary information with other codesigners, even though such information is needed to analyze and validate the overall design. We demonstrate the viability of codesign by multiple entities who view the parameters of their contributions to the joint design to be confidential. In addition to satisfying this confidentiality requirement, an online codesign process must result in a design that is of the same quality as if full sharing of information had taken place between the codesigners. We present online codesign protocols that satisfy both requirements and demonstrate their practicality using a simple example of codesign of an automotive suspension system and the tires. Our protocols do not use any cryptographic primitives—they only use the kinds of mathematical operations that are currently used in single-designer situations. The participants in the online design protocols include the codesigners, and a cloud server that facilitates the process while learning nothing about the participants' confidential information or about the characteristics of the codesigned system. The only assumption made about this cloud server is that it does not collude with some participants against other participants. We do not assume that the server does not, on its own, attempt to compute as much information as it can about the confidential inputs and outputs of the codesign process: It can make a transcript of the protocol and later attempt to infer all possible information from it, so it is a feature of our protocols the cloud server can infer nothing from such a transcript.
Effect of Thermal Conductivity Ratio on Laminar Double-Diffusive Free Convection in a Porous Cavity
Authors: Carvalho Paulo H. S. , de Lemos Marcelo J. S.
Published: May 2017

This work presents a study on double-diffusive free convection in a porous square cavity using the thermal equilibrium model. Transport equations are discretized using the control-volume method, and the system of algebraic equations is relaxed via the SIMPLE algorithm. The effect of ks/kf on average Nusselt and Sherwood values was investigated. Results show that increasing ks/kf affects Nuw and Shw boosting mass transfer at the expense of reducing overall heat transport across the enclosure.
Performance of a Laser Ignited Multicylinder Lean Burn Natural Gas Engine
Authors: Almansour Bader , Vasu Subith , Gupta Sreenath B. , Wang Qing , Van Leeuwen Robert , Ghosh Chuni
Published: May 2017

Market demands for lower fueling costs and higher specific powers in stationary natural gas engines have engine designs trending toward higher in-cylinder pressures and leaner combustion operation. However, ignition remains as the main limiting factor in achieving further performance improvements in these engines. Addressing this concern, while incorporating various recent advances in optics and laser technologies, laser igniters were designed and developed through numerous iterations. Final designs incorporated water-cooled, passively Q-switched, Nd:YAG microlasers that were optimized for stable operation under harsh engine conditions. Subsequently, the microlasers were installed in the individual cylinders of a lean-burn, 350 kW, inline six-cylinder, open-chamber, spark ignited engine, and tests were conducted. The engine was operated at high-load (298 kW) and rated speed (1800 rpm) conditions. Ignition timing (IT) sweeps and excess-air ratio (λ) sweeps were performed while keeping the NOx emissions below the United States Environmental Protection Agency (USEPA) regulated value (brake-specific NOx (BSNOx) < 1.34 g/kW h), and while maintaining ignition stability at industry acceptable values (coefficient of variation of integrated mean effective pressure (COV_IMEP) < 5%). Through such engine tests, the relative merits of (i) standard electrical ignition system and (ii) laser ignition system were determined. A rigorous combustion data analysis was performed and the main reasons leading to improved performance in the case of laser ignition were identified.
Model Predictive Engine Speed Control for Transmissions With Dog Clutches
Authors: Zhu Qilun , Prucka Robert , Prucka Michael , Dourra Hussein
Published: May 2017

The need for cost-effective fuel economy improvements has driven the introduction of automatic transmissions with an increasing number of gear ratios. Incorporation of interlocking dog clutches in these transmissions decreases package space and increases efficiency, as compared to conventional dry or wet clutches. Unlike friction-based clutches, interlocking dog clutches require very precise rotational speed matching prior to engagement. Precise engine speed control is, therefore, critical to maintaining high shift quality. This research focuses on controlling the engine speed during a gearshift period by manipulating throttle position and combustion phasing. Model predictive control (MPC) is advantageous in this application since the speed profile of a future prediction horizon is known with relatively high confidence. The MPC can find the optimal control actions to achieve the designated speed target without invoking unnecessary actuator manipulation and violating hardware and combustion constraints. This research utilizes linear parameter varying (LPV) MPC to control the engine speed during the gearshift period. Combustion stability constraints are considered with a control-oriented covariance of indicated mean effective pressure model (COV of IMEP). The proposed MPC engine speed controller is validated with a high-fidelity zero-dimensional engine model with crank angle resolution. Four case studies, based on simulation, investigate the impact of different MPC design parameters. They also demonstrate that the proposed MPC engine controller successfully achieves the speed reference tracking objective while considering combustion variation constraints.
Bistable Cantilevers Actuated by Fringing Electrostatic Fields
Authors: Krakover Naftaly , Krylov Slava
Published: May 2017

Bistable microstructures are distinguished by their ability to stay in two different stable configurations at the same loading. They manifest rich behavior and are advantageous in applications such as switches, nonvolatile memories, and sensors. Bistability of initially curved or buckled double-clamped beams, curved plates, and shells is associated with mechanical geometric nonlinearity appearing due to coupling between bending and compressive axial/in-plane stress. The bistable behavior is achieved by using a combination of carefully tailored initial shape and constrained boundaries. However, these statically indeterminate structures suffer from high sensitivity to temperature and residual stress. In this work, we show using the model that by combining electrostatic actuation by fringing fields with direct transversal forcing by a parallel-plate electrode or piezoelectric (PZT) transducer, bistable behavior can be obtained in a simple cantilever structure distinguished by robustness and low thermal sensitivity. Reduced-order model of the cantilever was built using Galerkin decomposition, the electrostatic force was obtained by means of three-dimensional (3D) finite elements (FEs) modeling. We also demonstrate that operation of the device in the vicinity of the bistability threshold may enhance the frequency sensitivity of the cantilever to loading. This sensitivity-enhancement approach may have applications in a broad range of resonant microelectromechanical inertial, force, mass, and biosensors as well as in atomic force microscopy (AFM).
How do we know that we are assessing the “right things”?
Authors: Rudland Joy , Lacey Cameron , Kenrick Kristin , Tweed Mike
Published: May 2017

Introduction: As assessment is perceived as a powerful tool for learning, it is important to ensure that assessments reflect the learning considered most significant. Assessment blueprinting offers the opportunity to ensure perceptions of what should be assessed align with what is assessed. Methods: An expert panel was asked to determine the percentage of undergraduate assessment that should be devoted to broad domain areas previously agreed to define the outcomes of an undergraduate curriculum; this provided the blueprint. Staff who co-ordinated, implemented and assessed students on clinical runs indicated the percentage of their assessments allocated to the domain areas. Staff who constructed end-of-year summative assessments also analysed their assessments in terms of the domain areas. The “expert panel” blueprint values were then compared using Mann–Whitney U with the actual assessment conducted to determine variations between the ideal and actual assessment. Results: What was considered important to assess closely aligned with what was assessed in most domain areas. The exceptions were the underassessment of two domains, Māori Health and Research and Information Literacy.Conclusions: The chosen methodology identified areas that were under-represented in the actual student assessments. This prompted the school to consider whether this under-representation is problematic; if so, whether to redistribute or increase assessment, and whether the required increases should occur in-course or at the end of the year.
Mg-corrosion, hydroxyapatite, and bone healing
Authors: Nygren Håkan , Bigdeli Narmin , Ilver Lars , Malmberg Per
Published: May 2017

The different capacities of magnesium in the metallic form (Mg-metal) and magnesium oxide (MgO) to stimulate bone healing are possible clues in the search for products that may promote bone healing. Since both Mg-metal and MgO can be assumed to release comparable amounts of Mg2+ ions during their reactions in the tissue where they have been implanted, it is of some importance to follow this process and analyze the resulting mineral formation in the tissue at the implantation site. Implants of MgO were inserted into rat tibia, and the bone healing was compared with sham-operated controls. Samples were taken after 1 week of healing and analyzed by histology, environmental scanning electron microscopy equipped with an energy dispersive x-ray spectroscopy analyzer, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Callus bone was seen in sham-operated controls after 1 week of healing. Implantation of MgO impaired the callus bone formation by replacing bone with apparently mineralized areas, lacking osteocytes and were denoted, amorphous bodies. Elemental analysis showed increased levels of Ca (7.1%), P (3.7%), and Mg (0.2%) in the bone marrow of MgO-treated animals versus sham-operated controls Ca (2.4%), P (2.3%), and Mg (0.1%). The Ca content of the cortical bone was also significantly increased (Ca, 29% increase) in MgO-treated animals compared to sham-operated controls. The Ca content of the cortical bone of sham-operated animals was also significantly (p < 0.05) higher than the corresponding value of untreated animals, which means that the surgical trauma induces an altered composition of the bone mineral. The Ca/P ratio was 1.26–1.68, which is compatible with that of mineralized bone with different contents of organic materials. Analysis of bone sections using ToF-SIMS showed the presence of hydroxyapatite (HA) and MgCO3 in the bone marrow and in cortical bone. Analysis using x-ray photoelectron spectroscopy of Mg, MgO, and MgCO3 after incubation with cell culture medium (DMEM), in vitro, showed binding of CaPO4 at the Mg and MgO samples. The Ca/P ratio was 0.8, indicating a higher P content than that expected for HA. Exposure of human embryonic stem cells to Mg species preincubated in DMEM resulted in HA production by the cells. Thus, two sources of CaPO4 in the bone marrow of MgO-treated bone were defined, catalytic formation on Mg-species and synthesis from activated stem-cells. The presented data suggest that bone healing near Mg implants is congruent with the fracture healing of bone, boosted by high HA levels in the bone marrow. In this context, the different capacities of Mg-metal and MgO to catalyse the formation of HA can be important clues to their different bone promoting effects.
Time-resolved photoemission studies of exciton dissociation in organic photovoltaics
Authors: Robey Steven W.
Published: May 2017

In the drive to improve efficiencies to market-penetration levels, organic photovoltaics would benefit from the introduction of new organic electronic materials in the form of nonfullerene acceptors, allowing the greater tunability of electronic levels and improved optical absorption. Efforts to incorporate new acceptors have produced limited results although the improvements have recently shown steady progress. Possible barriers to the use of nonfullerene acceptors include the formation of unfavorable morphologies in nonfullerene systems and/or favorable excitation/carrier delocalization in fullerenes, both factors that may be overcome through advanced synthesis. More problematic are suggestions that the molecular excited states of fullerenes lead to greatly enhanced dissociation of the initial S1 exciton in the donor material. This would suggest a fundamental limitation on the use of many nonfullerene acceptors. The authors tested this suggestion using time-resolved two-photon photoemission to directly compare exciton dissociation at the interfaces between phthalocyanine donors and a nonfullerene acceptor, perylene tetracarboxylic dianhydride, versus the analogous interface with the fullerene, C60. The authors conclude that for the systems studied, exciton dissociation rates are comparable with both the acceptors, leaving open the possibility of further improvements through the introduction of advanced acceptor materials.
A two-stage noise source identification technique based on a farfield random parametric array
Authors: Bai Mingsian R. , Chen You Siang , Lo Yi-Yang
Published: May 2017

A farfield random array is implemented for noise source identification. Microphone positions are optimized, with the aid of the simulated annealing method. A two-stage localization and separation algorithm is devised on the basis of the equivalent source method (ESM). In the localization stage, the active source regions are located by using the delay-and-sum method, followed by a parametric localization procedure, stochastic maximum likelihood algorithm. Multidimensional nonlinear optimization is exploited in the bearing estimation process. In the separation stage, source amplitudes are extracted by formulating an inverse problem based on the preceding source bearings identified. The number of equivalent sources is selected to be less than that of microphones to render an overdetermined problem which can be readily solved by using the Tikhonov regularization. Alternatively, the separation problem can be augmented into an underdetermined problem which can be solved by using the compressive sensing technique. Traditionally, farfield arrays only give a relative distribution of source field. However, by using the proposed method, the acoustic variables including sound pressure, particle velocity, sound intensity, and sound power can be calculated based on ESM. Numerical and experimental results of several objective and subjective tests are presented.
Converging to the baseline: Corpus evidence for convergence in speech rate to interlocutor's baseline
Authors: Cohen Priva Uriel , Edelist Lee , Gleason Emily
Published: May 2017

Speakers have been shown to alter their speech to resemble that of their conversational partner. Do speakers converge with their interlocutor's baseline, or does convergence stem from conversational properties that similarly affect both parties? Using the Switchboard corpus, this paper shows evidence for speakers' convergence in speech rate to the other party's baseline, not only to conversation-specific properties. Study 1 shows that the method for calculating speech rate used in this paper is powerful enough to replicate established findings. Study 2 demonstrates that speakers are mostly affected by their own behavior in other contexts, but that they also converge to their interlocutor's baseline, established using the interlocutor's behavior in other contexts. Study 2 also shows that speakers change their speech rate in response to the interlocutor's characteristics: speakers speak more slowly with older speakers regardless of the interlocutor's speech rate, and male speakers speak faster with other male speakers.