bluuebunny/crossref_metadata_2025 huggingface dataset:
Youth access to indoor tanning salons in urban versus rural/suburban communities
Authors: Nahar Vinayak K. , Rosenthal Meagen , Lemon Stephenie C. , Kane Kevin , Cheng Jie , Oleski Jessica L. , Li Wenjun , Hillhouse Joel J. , Pagoto Sherry L.
Published: October 2017

Background/Purpose

Research suggests that youth proximity to tanning salons may promote use; however, little is known about tanning salon proximity to schools. We assessed the proximity of tanning salons to schools in urban versus rural/suburban communities across Worcester County, Massachusetts (population > 800K). To put findings in context, we compared school proximity to tanning salons to school proximity to McDonald's restaurants, a large franchise that also caters to young people.

Materials & Methods

Accessibility was measured by ArcGIS10.2 Network Analyzer (ESRI, Redlands,CA,USA) and the most current road network data layer from Massachusetts Department of Transportation (MassDOT).

Results

A total of 145 schools were observed in the study area, of which about 39% of schools were within 1 mile from a tanning salon. Urban schools (53.41%) had a higher proportion within 1 mile of a tanning salon than rural/suburban schools (17.54%;P < .001). More schools (39.31%) were within 1 mile of a tanning salon than schools within 1 mile of a McDonald's (22.70%;P < .001).

Conclusions

Schools may be particularly impactful for implementing skin cancer prevention programing.
Prognostic Significance of Macroscopic Appearance in Clear Cell Renal Cell Carcinoma and Its Metastasis‐Predicting Model
Authors: Jeong Se Un , Park Ja‐Min , Shin Su‐Jin , Lee JungBok , Song Cheryn , Go Heounjeong , Cho Nam Hoon , Ro Jae Y. , Cho Yong Mee
Published: October 2017

Prognostic significance of macroscopic appearance of clear cell renal cell carcinoma (ccRCC) has not yet been studied. This study aimed to define the prognostic significance of macroscopic appearance and to propose a prognostic model for post‐operative metastasis in ccRCC. A total of 1,025 patients with ccRCC were analyzed for the development dataset. A separate cohort of 399 such patients was used as an external validation dataset. Macroscopic appearances were initially divided into four groups, but were later divided into two groups: a simple nodular group (700 cases, 68.3%) and an irregular outline group (325 cases, 32.7%). During the 66.1‐month mean follow‐up period, 98 patients (9.6%) developed metastasis. Univariate analysis revealed that metastasis was associated with older age, radical nephrectomy, larger tumor size, higher tumor grade and stage, and the irregular outline group. On multivariate analysis, age, tumor size, and macroscopic appearance remained as independent prognostic factors. These factors were used to build a prognostic model, which divided into three risk groups. The probabilities of 5‐year metastasis‐free survival in the low‐, intermediate‐, and high‐risk groups were 98%, 83%, and 53%, respectively. The results showed prognostic significance of macroscopic appearance in ccRCC and propose a prognostic model to guide post‐operative management of patients with ccRCC.
Identification of tomato introgression lines with enhanced susceptibility or resistance to infection by parasitic giant dodder (Cuscuta reflexa)
Authors: Krause Kirsten , Johnsen Hanne R. , Pielach Anna , Lund Leidulf , Fischer Karsten , Rose Jocelyn K.C.
Published: October 2017

The parasitic flowering plant genus Cuscuta (dodder) is a parasitic weed that infects many important crops. Once it winds around the shoots of potential host plants and initiates the development of penetration organs, called haustoria, only a few plant species have been shown to deploy effective defense mechanisms to ward off Cuscuta parasitization. However, a notable exception is Solanum lycopersicum (tomato), which exhibits a local hypersensitive reaction when attacked by giant dodder (Cuscuta reflexa). Interestingly, the closely related wild desert tomato, Solanum pennellii, is unable to stop the penetration of its tissue by the C. reflexa haustoria. In this study, we observed that grafting a S. pennellii scion onto the rootstock of the resistant S. lycopersicum did not change the susceptibility phenotype of S. pennellii. This suggests that hormones, or other mobile substances, produced by S. lycopersicum do not induce a defense reaction in the susceptible tissue. Screening of a population of introgression lines harboring chromosome fragments from S. pennellii in the genome of the recurrent parent S. lycopersicum, revealed that most lines exhibit the same defense reaction as shown by the S. lycopersicum parental line. However, several lines showed different responses and exhibited either susceptibility, or cell death that extended considerably beyond the infection site. These lines will be valuable for the future identification of key loci involved in the perception of, and resistance to, C. reflexa and for developing strategies to enhance resistance to infection in crop species.
Scandinavian perspectives on plant gene technology: applications, policies and progress
Authors: Eriksson Dennis , Brinch‐Pedersen Henrik , Chawade Aakash , Holme Inger B. , Hvoslef‐Eide Trine A.K. , Ritala Anneli , Teeri Teemu H. , Thorstensen Tage
Published: October 2017

Plant research and breeding has a long and successful history in the Scandinavian countries, Denmark, Finland, Norway and Sweden. Researchers in the region have been early in adopting plant gene technologies as they developed. This review gives a background, as well as discuss the current and future progress of plant gene technology in these four countries. Country‐specific details of the regulation of genetically modified plants are described, as well as similarities and differences in the approach to regulation of novel genome‐editing techniques. Also, the development of a sustainable bioeconomy may encompass the application of plant gene technology and we discuss whether or not this is reflected in current associated national strategies. In addition, country‐specific information about the opinion of the public and other stakeholders on plant gene technology is presented, together with a country‐wise political comparison and a discussion of the potential reciprocal influence between public opinion and the political process of policy development. The Scandinavian region is unique in several aspects, such as climate and certain agriculturally related regulations, and at the same time the region is vulnerable to changes in plant breeding investments due to the relatively small market sizes. It is therefore important to discuss the role and regulation of innovative solutions in Scandinavian plant research and breeding.
Elevated CO2 levels enhance the uptake and metabolism of organic nitrogen
Authors: Ma Qingxu , Wang Jun , Sun Yan , Yang Xin , Ma Jinzhao , Li Tingqiang , Wu Lianghuan
Published: October 2017

The effects of elevated CO2 (eCO2) on the relative uptake of inorganic and organic nitrogen (N) are unclear. The uptake of different N sources by pak choi (Brassica chinensis L.) seedlings supplied with a mixture of nitrate, glycine and ammonium was studied using 15N‐labelling under ambient CO2 (aCO2) (350 ppm) or eCO2 (650 ppm) conditions. 15N‐labelled short‐term uptake and 15N‐gas chromatography mass spectrometry (GC–MS) were applied to measure the effects of eCO2 on glycine uptake and metabolism. Elevated CO2 increased the shoot biomass by 36% over 15 days, but had little effect on root growth. Over the same period, the N concentrations of shoots and roots were decreased by 30 and 2%, respectively. Elevated CO2 enhanced the uptake and N contribution of glycine, which accounted for 38–44% and 21–40% of total N uptake in roots and shoots, respectively, while the uptake of nitrate and ammonium was reduced. The increased glycine uptake resulted from the enhanced active uptake and enhanced metabolism in the roots. We conclude that eCO2 may increase the uptake and contribution of organic N forms to total plant N nutrition. Our findings provide new insights into plant N regulation under eCO2 conditions.
Comparison of in vitro and in vivo fertilizing potential of buffalo bull semen frozen in egg yolk‐, soya bean lecithin‐ and liposome‐based extenders
Authors: Singh AK , Kumar A , Honparkhe M , Kaur S , Kaur H , Ghuman SPS , Brar PS
Published: October 2017

Contents

The objective of this study was to compare different extenders for post‐thaw in vitro sperm function and in vivo fertility of buffalo semen. Accordingly, sperm of 30 ejaculates extended in egg yolk (TRIS with 20% egg yolk; EY), two soya lecithin‐based (SL‐1; AndroMed® and SL‐2; Bioxcell®) and a liposome‐based extender (LS; OptiXcell®) were tested. The post‐thaw semen was evaluated for computer‐assisted sperm analysis (CASA), sperm viability, membrane and acrosome integrity, DNA integrity and acrosome reaction and first service pregnancy rate (FSPR) in a fixed‐time artificial insemination programme. Total motility and VCL were the only CASA‐based parameters that exhibited significantly higher (p < .05) percentage in LS among these extenders. Post‐thaw percentage of acrosome integrity (55.9 ± 1.4, 58.1 ± 2.0, 55.8 ± 2.0, 56.6 ± 2.3) and DNA integrity (68.8 ± 2.0, 69.2 ± 2.3, 71.3 ± 2.1, 69.1 ± 2.1) did not differ (p > .05) in EY, SL‐1, SL‐2 and LS extender, respectively. However, a variable response in terms of efficacy of different extenders for sperm viability and plasma membrane integrity was observed. Assessment of inducibility of acrosome reaction showed significant differences between extenders (51.9 ± 2.1, 44.3 ± 2.4, 46.1 ± 2.3 and 58.1 ± 3.1%, respectively, for EY, SL‐1, SL‐2 and LS). Furthermore, field trials revealed significantly higher (p < .05) FSPR of LS‐extended semen as compared to that for EY, SL‐1 and SL‐2 extender (46.3%, 41.2%, 31.2% and 29.7%, respectively). It is concluded that the liposome‐based extender is more effective than egg yolk‐ and soya lecithin‐based extenders and may be used for cryopreservation of buffalo semen in the future.
Detecting and Dating Structural Breaks in Functional Data Without Dimension Reduction
Authors: Aue Alexander , Rice Gregory , Sönmez Ozan
Published: October 2017

Methodology is proposed to uncover structural breaks in functional data that is ‘fully functional’ in the sense that it does not rely on dimension reduction techniques. A thorough asymptotic theory is developed for a fully functional break detection procedure as well as for a break date estimator, assuming a fixed break size and a shrinking break size. The latter result is utilized to derive confidence intervals for the unknown break date. The main results highlight that the fully functional procedures perform best under conditions when analogous estimators based on functional principal component analysis are at their worst, namely when the feature of interest is orthogonal to the leading principal components of the data. The theoretical findings are confirmed by means of a Monte Carlo simulation study in finite samples. An application to annual temperature curves illustrates the practical relevance of the procedures proposed.
The framing of research questions using the PICOT format in randomized controlled trials of venous ulcer disease is suboptimal: A systematic survey
Authors: Abbade Luciana P.F. , Wang Mei , Sriganesh Kamath , Jin Yanling , Mbuagbaw Lawrence , Thabane Lehana
Published: October 2017

Despite several publications on venous ulcers, there is still a lack of evidence from randomized controlled trials (RCTs) to support certain treatments for patients with this disorder. Well‐designed research questions using the PICOT (Population; Intervention; Comparator; Outcome; Time‐frame) format in RCTs can improve the quality of research. The objectives of this study were to assess how the PICOT format is used to frame research questions in RCTs published on venous ulcer disease and to determine the factors associated with better adherence to the PICOT format. We conducted a systematic survey of RCTs on venous ulcers published in the PubMed database between January 2009 and May 2016. All RCTs published in English addressing therapeutic interventions for venous ulcer disease in human subjects were included. We examined whether the five elements of the PICOT format were used in formulating the research question and scored them between 0 and 5. The primary outcome of this systematic survey was the percentage of studies that adequately reported all five PICOT elements. Eighty‐five (85) RCTs were included with median PICOT score of 3 (IQR = 1.5). Four elements of PICOT were present in 28 reports (32.9%) and only 2 RCTS (2.3%) reported all the PICOT elements. Population and intervention were often appropriately described, in (70/85) 82.4% and (83/85) 97.6% of the studies, respectively; however, comparison intervention and outcome were presented in only (53/85) 62.3% and (48/85) 56.5% of studies, respectively. Very few RCTs (7.1%; 6/85) reported the study time frame. No journal or RCT characteristics were found to be significantly associated with better reporting. Use of the PICOT format to frame research questions in RCTs published on venous ulcers is suboptimal, and our study reinforces the importance of framing a good research question to improve the design of trials and quality of evidence in venous ulcer disease.
Assessing diagnostic coding practices among a sample of healthcare facilities in Lyme disease endemic areas: Maryland and New York – A Brief Report
Authors: Thomas N. , Rutz H. J. , Hook S. A. , Hinckley A. F. , Lukacik G. , Backenson B. P. , Feldman K. A. , White J. L.
Published: October 2017

The value of using diagnostic codes in Lyme disease (LD) surveillance in highly endemic states has not been well studied. Surveys of healthcare facilities in Maryland (MD) and New York (NY) regarding coding practices were conducted to evaluate the feasibility of using diagnostic codes as a potential method for LD surveillance. Most respondents indicated that their practice utilized electronic medical records (53%) and processed medical/billing claims electronically (74%). Most facilities were able to search office visits associated with specific ICD‐9‐CM and CPT codes (74% and 73%, respectively); no discernible differences existed between the healthcare facilities in both states. These codes were most commonly assigned by the practitioner (82%), and approximately 70% of respondents indicated that these codes were later validated by administrative staff. These results provide evidence for the possibility of using diagnostic codes in LD surveillance. However, the utility of these codes as an alternative to traditional LD surveillance requires further evaluation.
Changes in the prevalence, genotypes and antimicrobial resistance phenotypes of non‐typhoidal Salmonella recovered from mail‐order hatchling poultry sold at US feed stores, 2013–2015
Authors: Sharma A. , Erdman M. M. , Muñoz‐Vargas L. , Mollenkopf D. F. , Habing G. G.
Published: October 2017

Every year, multiple outbreaks of salmonellosis in humans are linked to contact with mail‐order chicks and ducks. The objective of this study was to describe the temporal changes in the prevalence of serovars, genotypes and antimicrobial resistance (AMR) phenotypes of non‐typhoidal Salmonella (NTS) recovered from shipped boxes of mail‐order hatchling poultry in the United States during 2013 to 2015. In each year, a sample of feed stores belonging to a single national chain participated in the study. The store employees submitted swabs or hatchling pads from hatchling boxes and shipment tracking information of the arriving boxes to the investigators. NTS was cultured from the samples and isolates were sent to the National Veterinary Services Laboratories (Ames, IA) for serotyping, pulsed‐field gel electrophoresis (PFGE) and AMR phenotyping. The PFGE patterns of Salmonella serovars isolated from hatchling boxes were compared with those from human outbreaks of salmonellosis linked to live poultry contact. The box‐level prevalence of NTS was significantly higher in 2015 compared to 2014. Also, the population of Salmonella serovars recovered in 2015 was more diverse and substantially different from those recovered in the previous two years. Of PFGE patterns recovered from hatchling boxes, seven distinct patterns in 2015, three in 2014 and four in 2013 were indistinguishable from the PFGE patterns of human outbreaks‐associated strains in the respective years. Importantly, a significant positive correlation was found between the box‐level prevalence of PFGE patterns and the number of human illnesses associated with the same patterns. Also, the proportion of multidrug‐resistant isolates was higher in 2014 and 2015 compared to that in 2013. The results demonstrate that shipments of mail‐order hatchling poultry are frequently contaminated with Salmonella genotypes indistinguishable from human outbreaks‐associated strains each year, and control efforts at hatchery level are likely to have an important public health impact.
Proverbs and Idioms in Children's Books
Authors: Hayran Zeynel
Published: October 2017

In this study, it was searched for the extent to which proverbs and idioms were included in the children's books that were taught to elementary school students. Children's books which are taught at the stage of children's vocabulary enriched rapidly and significantly, present the vocabulary of the mother tongue and its universe of meaning to a child. The richness of a vocabulary provides superiority to the students in terms of human relations and their learning. Proverbs which are one of the elements that constitute the vocabulary of Turkish; are concise words that reflect society's wisdom, experiences, and expression power; idioms, on the other hand, are a stereotyped phrase which states a concept or a situation with an attractive narrative and which also has a side meaning. The method of this study is to document review. Within the scope of the study, children's books that are taught to elementary school students are described in terms of their use of proverbs and idiomatic expressions. The results obtained from the research are discussed in the light of literature, and suggestions for the researchers, teachers and authors are presented with the collected findings.
An application of the new function method to the Zhiber–Shabat equation
Authors: Aktürk Tolga , Gürefe Yusuf , Pandır Yusuf
Published: October 2017

This paper applies a new approach including the trial equation based on the exponential function in order to find new traveling wave solutions to Zhiber-Shabat equation. By the using of this method, we obtain a new elliptic integral function solution. Also, this solution can be converted into Jacobi elliptic functions solution by a simple transformation.
C1 neurons: a nodal point for stress?
Authors: Stornetta Ruth L. , Guyenet Patrice G.
Published: October 2017

New Findings

What is the topic of this review?

The C1 neurons (C1) innervate sympathetic and parasympathetic preganglionic neurons plus numerous brain nuclei implicated in stress, arousal and autonomic regulations. We consider here the contribution of C1 to stress‐induced responses.

What advances does it highlight?

C1 activation is required for blood pressure stability during hypoxia and mild hemorrhage which exemplifies their homeostatic function. During restraint stress, C1 activate the splenic anti‐inflammatory pathway resulting in tissue protection against ischemic injury. This effect, along with glucose release and, possibly, arousal are examples of adaptive non‐homeostatic responses to stress that are also mediated by C1.

The C1 cells are catecholaminergic and glutamatergic neurons located in the rostral ventrolateral medulla. Collectively, these neurons innervate sympathetic and parasympathetic preganglionic neurons, the hypothalamic paraventricular nucleus and countless brain structures involved in autonomic regulation, arousal and stress. Optogenetic inhibition of rostral C1 neurons has little effect on blood pressure (BP) at rest in conscious rats but produces large reductions in BP when the animals are anaesthetized or exposed to hypoxia. Optogenetic C1 stimulation increases BP and produces arousal from non‐rapid eye movement sleep. C1 cell stimulation mimics the effect of restraint stress to attenuate kidney injury caused by renal ischaemia–reperfusion. These effects are mediated by the sympathetic nervous system through the spleen and eliminated by silencing the C1 neurons. These few examples illustrate that, depending on the nature of the stress, the C1 cells mediate adaptive responses of a homeostatic or allostatic nature.
Mechanical Fatigue of Bovine Cortical Bone Using Ground Reaction Force Waveforms in Running
Authors: Loundagin Lindsay L. , Schmidt Tannin A. , Edwards W. Brent
Published: October 2017

Stress fractures are a common overuse injury among runners associated with the mechanical fatigue of bone. Several in vivo biomechanical studies have investigated specific characteristics of the vertical ground reaction force (vGRF) in heel-toe running and have observed an association between increased loading rate during impact and individuals with a history of stress fracture. The purpose of this study was to examine the fatigue behavior of cortical bone using vGRF-like loading profiles, including those that had been decomposed into their respective impact and active phase components. Thirty-eight cylindrical cortical bone samples were extracted from bovine tibiae and femora. Hydrated samples were fatigue tested at room temperature in zero compression under load control using either a raw (n = 10), active (n = 10), low impact (n = 10), or high impact (n = 8) vGRF profile. The number of cycles to failure was quantified and the test was terminated if the sample survived 105 cycles. Fatigue life was significantly greater for both impact groups compared to the active (p < 0.001) and raw (p < 0.001) groups, with all low impact samples and 6 of 8 high impact samples surviving 105 cycles. The mean (± SD) number of cycles to failure for the active and raw groups was 12,133±11,704 and 16,552±29,612, respectively. The results suggest that loading rates associated with the impact phase of a typical vGRF in running have little influence on the mechanical fatigue behavior of bone relative to loading magnitude, warranting further investigation of the mechanism by which increased loading rates are associated with stress fracture.
High-Resolution Computational Fluid Dynamic Simulation of Haemodialysis Cannulation in a Patient-Specific Arteriovenous Fistula
Authors: Fulker David , Ene-Iordache Bogdan , Barber Tracie
Published: October 2017

Arteriovenous fistulae (AVF) are the preferred choice of vascular access in hemodialysis patients; however, complications such as stenosis can lead to access failure or recirculation, which reduces dialysis efficiency. This study utilized computational fluid dynamics on a patient-specific radiocephalic fistula under hemodialysis treatment to determine the dynamics of access recirculation and identify the presence of disturbed flow. Metrics of transverse wall shear stress (transWSS) and oscillatory shear index (OSI) were used to characterize the disturbed flow acting on the blood vessel wall, while a power spectral density (PSD) analysis was used to calculate the any turbulence within the access. Results showed that turbulence is generated at the anastomosis and continues through the swing segment. The arterial needle dampens the flow as blood is extracted to the dialyzer, while the venous needle reintroduces turbulence due to the presence of jet flows. Adverse shear stresses are present throughout the vascular access and coincide with these complex flow fields. The position of the needles had no effect in minimizing these forces. However, improved blood extraction may occur when the arterial needle is placed further from the anastomosis, minimizing the effects of residual turbulent structures generated at the anastomosis. Furthermore, the arterial and venous needle may be placed in close proximity to each other without increasing the risk of access recirculation, in a healthy mature fistula, due to the relatively stable blood flow in this region. This may negate the need for a long cannulation segment and aid clinicians in optimizing needle placement for hemodialysis.
Delayed Reaction–Diffusion Cellular Neural Networks of Fractional Order: Mittag–Leffler Stability and Synchronization
Authors: Stamova Ivanka M. , Simeonov Stanislav
Published: October 2017

This research introduces a model of a delayed reaction–diffusion fractional neural network with time-varying delays. The Mittag–Leffler-type stability of the solutions is investigated, and new sufficient conditions are established by the use of the fractional Lyapunov method. Mittag–Leffler-type synchronization criteria are also derived. Three illustrative examples are established to exhibit the proposed sufficient conditions.
Development of a Dexterous Prosthetic Hand
Authors: Owen Mahonri , Au ChiKit , Fowke Andrew
Published: October 2017

An anthropomorphic, under-actuated, prosthetic hand has been designed and developed for upper extremity amputees. This paper proposes a dexterity focused approach to the design of an anthropomorphic electromechanical hand for transradial amputees. Dexterity is increased by the improvement of thumb position, orientation, and work space. The fingers of the hand are also capable of adduction and abduction. It is the intent of this research project to aid the rehabilitation of upper extremity amputees by increasing the amount of tasks the hand can execute. Function and control of the hand are based on micro servo actuation and information acquired from the brain. Electroencephalography (EEG) is used to attain the mental state of the user, which triggers the prosthetic hand. This paper focuses on the mechanical arrangement of the hand and investigates the effect of increasing the degrees-of-freedom (DOFs) the thumb and fingers have.
Automatic Detection of Fasteners From Tessellated Mechanical Assembly Models
Authors: Rafibakhsh Nima , Huang Weifeng , Campbell Matthew I.
Published: October 2017

In this paper, we present multiple methods to detect fasteners (bolts, screws, and nuts) from tessellated mechanical assembly models. There is a need to detect these geometries in tessellated formats because of features that are lost during the conversions from other geometry representations to tessellation. Two geometry-based algorithms, projected thread detector (PTD) and helix detector (HD), and four machine learning classifiers, voted perceptron (VP), Naïve Bayes (NB), linear discriminant analysis, and Gaussian process (GP), are implemented to detect fasteners. These six methods are compared and contrasted to arrive at an understanding of how to best perform this detection in practice on large assemblies. Furthermore, the degree of certainty of the automatic detection is also developed and examined so that a user may be queried when the automatic detection leads to a low certainty in the classification. This certainty measure is developed with three probabilistic classifier approaches and one fuzzy logic-based method. Finally, once the fasteners are detected, the authors show how the thread angle, the number of threads, the length, and major and root diameters can be determined. All of the mentioned methods are implemented and compared in this paper. A proposed combination of methods leads to an accurate and robust approach of performing fastener detection.
Design and Experimental Assessment of Variable-Geometry Dies for Polymer Extrusion
Authors: Li Bingjue , Myszka David H. , Murray Andrew P.
Published: October 2017

This paper presents a design methodology and experimental assessment of variable-geometry dies that enable the extrusion of plastic parts with a nonconstant cross section. These shape-changing dies can produce complex plastic components at higher manufacturing speeds and with lower tooling costs than injection molding. Planar, rigid-body, shape-changing mechanism synthesis techniques are used to create the links that comprise the variable-geometry die exit orifice. Mechanical design guidelines for production-worthy dies are proposed. Several dies were designed and constructed to provide significant changes in the cross-sectional shape and area of extruded parts. Experiments were conducted in a production environment. An analysis of the repeatability of the cross-sectional profiles along the length of the part is presented.
Sensitivity-Based Parameter Calibration and Model Validation Under Model Error
Authors: Qiu Na , Park Chanyoung , Gao Yunkai , Fang Jianguang , Sun Guangyong , Kim Nam H.
Published: October 2017

In calibrating model parameters, it is important to include the model discrepancy term in order to capture missing physics in simulation, which can result from numerical, measurement, and modeling errors. Ignoring the discrepancy may lead to biased calibration parameters and predictions, even with an increasing number of observations. In this paper, a simple yet efficient calibration method is proposed based on sensitivity information when the simulation model has a model error and/or numerical error but only a small number of observations are available. The sensitivity-based calibration method captures the trend of observation data by matching the slope of simulation predictions and observations at different designs and then utilizing a constant value to compensate for the model discrepancy. The sensitivity-based calibration is compared with the conventional least squares calibration method and Bayesian calibration method in terms of parameter estimation and model prediction accuracies. A cantilever beam example, as well as a honeycomb tube crush example, is used to illustrate the calibration process of these three methods. It turned out that the sensitivity-based method has a similar performance with the Bayesian calibration method and performs much better than the conventional method in parameter estimation and prediction accuracy.
Design, Development, and Evaluation of a Control Framework for an Atkinson Cycle Engine
Authors: Murtaza G. , Bhatti A. I. , Ahmed Q.
Published: October 2017

The efficiency of the spark ignition (SI) engine degrades while working at part loads. It can be optimally dealt with a slightly different thermodynamic cycle termed as an Atkinson cycle. It can be implemented in the conventional SI engines by incorporating advanced mechanisms as variable valve timing (VVT) and variable compression ratio (VCR). In this research, a control framework for the Atkinson cycle engine with flexible intake valve load control strategy is designed and developed. The control framework based on the extended mean value engine model (EMVEM) of the Atkinson cycle engine is evaluated in the view of fuel economy at the medium and higher load operating conditions for the standard new European driving cycle (NEDC), federal urban driving schedule (FUDS), and federal highway driving schedule (FHDS) cycles. In this context, the authors have already proposed a control-oriented EMVEM model of the Atkinson cycle engine with variable intake valve actuation. To demonstrate the potential benefits of the VCR Atkinson cycle VVT engine, for the various driving cycles, in the presence of auxiliary loads and uncertain road loads, its EMVEM model is simulated by using a controller having similar specifications as that of the conventional gasoline engine. The simulation results point toward the significant reduction in engine part load losses and improvement in the thermal efficiency. Consequently, considerable enhancement in the fuel economy of the VCR Atkinson cycle VVT engine is achieved over conventional Otto cycle engine during the NEDC, FUDS, and FHDS cycles.
Implementation of a Finite Element Model for Gear Stress Analysis Based on Tie-Surface Constraints and Its Validation Through the Hertz's Theory
Authors: Gonzalez-Perez Ignacio , Fuentes-Aznar Alfonso
Published: October 2017

A new finite element model for stress analysis of gear drives is proposed. Tie-surface constraints are applied at each tooth of the gear model to obtain meshes that can be independently defined: a finer mesh at contact surfaces and fillet and a coarser mesh in the remaining part of the tooth. Tie-surface constraints are also applied for the connection of several teeth in the model. The model is validated by application of the Hertz's theory in a spiral bevel gear drive with localized bearing contact and by observation of convergency of contact and bending stresses. Maximum contact pressure, maximum Mises stress, maximum Tresca stress, maximum major principal stress, and loaded transmission errors are evaluated along two cycles of meshing. The effects of the boundary conditions that models with three, five, seven, and all the teeth of the gear drive provide on the above-mentioned variables are discussed. Several numerical examples are presented.
Nonlinear Parametric Reduced-Order Model for the Structural Dynamics of Hybrid Electric Vehicle Batteries
Authors: Lu Jauching , D'Souza Kiran , Castanier Matthew P. , Epureanu Bogdan I.
Published: October 2017

Battery packs used in electrified vehicles exhibit high modal density due to their repeated cell substructures. If the excitation contains frequencies in the region of high modal density, small commonly occurring structural variations can lead to drastic changes in the vibration response. The battery pack fatigue life depends strongly on their vibration response; thus, a statistical analysis of the vibration response with structural variations is important from a design point of view. In this work, parametric reduced-order models (PROMs) are created to efficiently and accurately predict the vibration response in Monte Carlo calculations, which account for stochastic structural variations. Additionally, an efficient iterative approach to handle material nonlinearities used in battery packs is proposed to augment the PROMs. The nonlinear structural behavior is explored, and numerical results are provided to validate the proposed models against full-order finite element approaches.
New Graph Representation for Planetary Gear Trains
Authors: Yang Wenjian , Ding Huafeng , Zi Bin , Zhang Dan
Published: October 2017

Planetary gear trains (PGTs) are widely used in machinery to transmit angular velocity ratios or torque ratios. The graph theory has been proved to be an effective tool to synthesize and analyze PGTs. This paper aims to propose a new graph model, which has some merits relative to the existing ones, to represent the structure of PGTs. First, the rotation graph and canonical rotation graph of PGTs are defined. Then, by considering the edge levels in the rotation graph, the displacement graph and canonical displacement graph are defined. Each displacement graph corresponds to a PGT having the specified functional characteristics. The synthesis of five-link one degree-of-freedom (1DOF) PGTs is used as an example to interpret and demonstrate the applicability of the present graph representation in the synthesis process. The present graph representation can completely avoid the generation of pseudo-isomorphic graphs and can be used in the computer-aided synthesis and analysis of PGTs.
A Unified Approach to Exact and Approximate Motion Synthesis of Spherical Four-Bar Linkages Via Kinematic Mapping
Authors: Li Xiangyun , Zhao Ping , Purwar Anurag , Ge Q. J.
Published: October 2017

This paper studies the problem of spherical four-bar motion synthesis from the viewpoint of acquiring circular geometric constraints from a set of prescribed spherical poses. The proposed approach extends our planar four-bar linkage synthesis work to spherical case. Using the image space representation of spherical poses, a quadratic equation with ten linear homogeneous coefficients, which corresponds to a constraint manifold in the image space, can be obtained to represent a spherical RR dyad. Therefore, our approach to synthesizing a spherical four-bar linkage decomposes into two steps. First, find a pencil of general manifolds that best fit the task image points in the least-squares sense, which can be solved using singular value decomposition (SVD), and the singular vectors associated with the smallest singular values are used to form the null-space solution of the pencil of general manifolds; second, additional constraint equations on the resulting solution space are imposed to identify the general manifolds that are qualified to become the constraint manifolds, which can represent the spherical circular constraints and thus their corresponding spherical dyads. After the inverse computation that converts the coefficients of the constraint manifolds to the design parameters of spherical RR dyad, spherical four-bar linkages that best navigate through the set of task poses can be constructed by the obtained dyads. The result is a fast and efficient algorithm that extracts the geometric constraints associated with a spherical motion task, and leads naturally to a unified treatment for both exact and approximate spherical motion synthesis.
Full-Mobility Three-CCC Parallel-Kinematics Machines: Kinematics and Isotropic Design
Authors: Li Wei , Angeles Jorge
Published: October 2017

The subject of this paper is twofold: the kinematics and the isotropic design of six degrees-of-freedom (DOF), three-CCC parallel-kinematics machines (PKMs). Upon proper embodiment and dimensioning, the PKMs discussed here, with all actuators mounted on the base, exhibit interesting features, not found elsewhere. One is the existence of an isotropy locus, as opposed to isolated isotropy points in the workspace, thereby guaranteeing the accuracy and the homogeneity of the motion of the moving platform (MP) along different directions within a significantly large region of their workspace. The conditions leading to such a locus are discussed in depth; several typical isotropic designs are brought to the limelight. Moreover, the kinematic analysis shows that rotation and translation of the MP are decoupled, which greatly simplifies not only the kinetostatic analysis but also, most importantly, their control. Moreover, it is shown that the singularity loci of this class of mechanism are determined only by the orientation of their MP, which also simplifies locus evaluation and eases its representation.
A Novel Graft Fixation Technique for Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Grafts
Authors: Li Guoan , Hosseini Ali , Gadikota Hemanth , Gill Thomas
Published: October 2017

This study evaluated the biomechanical efficacy of single-tunnel double-bundle anterior cruciate ligament (ACL) reconstruction technique. The graft construct is achieved using a novel fixation device that splits an ACL (SPACL) graft into two bundles, recreating the anteromedial (AM) and posterolateral (PL) bundles for ACL reconstruction. A pullout strength test of the SPACL was performed using a 7-mm bovine digital extensor tendon graft. The capability in restoration of knee kinematics after SPACL reconstruction was investigated using cadaveric human knees on a robotic testing system under an anterior tibial load of 134 N and a simulated quadriceps load of 400 N. The data indicated that the SPACL graft has a pullout strength of 823.7±172.3 N. Under the 134 N anterior tibial load, the anteroposterior joint laxity had increased constraint using the SPACL reconstruction but not significantly (p > 0.05) at all selected flexion angles. Under the 400 N quadriceps load, no significant differences were observed between the anterior tibial translation of intact knee and SPACL conditions at all selected flexion angles, but the SPACL graft induced a significant increase in external tibial rotation compared to the intact knee condition at all selected flexion angles with a maximal external rotation of −3.20 deg ±3.6 deg at 90 deg flexion. These data showed that the SPACL technique is equivalent or superior to existing ACL reconstruction techniques in restoration of knee laxity and kinematics. The new SPACL reconstruction technique could provide a valuable alternation to contemporary ACL reconstruction surgery by more closely recreating native ACL kinematics.
Interaction Between Circumferential Lamb Waves and Lamination in the Midplane of a Metallic Pipe
Authors: Li Ziming , He Cunfu , Liu Zenghua , Lu Yan , Wu Bin
Published: October 2017

Lamination is one of common defects in the manufacturing process of seamless metallic pipes. In this paper, the interaction between the circumferential Lamb waves and lamination in the midplane of an aluminum pipe is studied. The used circumferential Lamb waves are CL0 and CL1 modes generated with a finite element method code. Lamination along the circumferential direction is established by the demerging-node method. Numerical results of arrival time are compared with theoretical results in order to verify the accuracy of the excitation ways. The interaction between circumferential Lamb waves and lamination in a damaged full circular pipe is analyzed by composing the received waveforms of the corresponding receivers when CL0 and CL1 modes are excited at different excitation positions: the inner subpipe, the outer subpipe, and the main pipe. The composed waveforms fit well with the original waveforms. When CL0/CL1 mode reaches the entrance and exit of a lamination, it generates new mode and undergoes multiple reverberations, diffraction, and mode conversion between the two ends of the lamination. Based on the detailed analysis of the waveform in detail, some phenomena, which are different from those in a plate, are observed.
Numerical Validations of Flaw Shape Idealization Methods to Burst Pressure Estimations of Steam Generator Tube With Axial Surface Flaws
Authors: Park Seung-Hyun , Choi Jae-Boong , Huh Nam-Su , Lee Sang-Min , Kim Yong-Beum
Published: October 2017

This work investigates the applicability of the flaw shape idealization methods to carry out the structural integrity assessment of steam generator (SG) tubes under internal pressure with complicated axial inner and outer surface flaws that were typically found during the in-service-inspection (ISI). In terms of flaw shape, three different shapes of flaws which can be detected during an actual ISI are considered, i.e., long symmetric flaw, asymmetric inclined flaw and narrow, symmetric deep flaw. As for flaw shape idealization methods for the predictions of burst pressures of these flaws, four different flaw shape idealization models, i.e., semi-elliptical, rectangular, maximum length with effective flaw depth and weakest subcrack model proposed by the Electric Power Research Institute (EPRI) are employed in this work. In order to validate the applicability of these idealization methods, the burst pressures of SG tubes with these flaws are investigated by using the finite element (FE) analyses. By comparing the predictions of the burst pressures based on the four different flaw shape idealization methods with those based on actual flaw shapes, it is found that the weakest subcrack model proposed by the EPRI and maximum length with effective flaw depth model provide the better agreement with actual complex flaw.
Topology Optimization of Robust District Heating Networks
Authors: Pizzolato Alberto , Sciacovelli Adriano , Verda Vittorio
Published: October 2017

Large district heating networks greatly benefit from topological changes brought by the construction of loops. The overall effects of malfunctions are smoothed, making existing networks intrinsically robust. In this paper, we demonstrate the use of topology optimization to find the network layout that maximizes robustness under an investment constraint. The optimized design stems from a large ground structure that includes all the possible looping elements. The objective is an original robustness measure, that neither requires any probabilistic analysis of the input uncertainty nor the identification of bounds on stochastic variables. Our case study on the Turin district heating network confirms that robustness and cost are antagonist objectives: the optimized designs obtained by systematically relaxing the investment constraint lay on a smooth Pareto front. A sudden steepness variation divides the front in two different regions. For small investments topological modifications are observed, i.e., new branches appear continuously in the optimized layout as the investment increases. Here, large robustness improvements are possible. However, at high investments no topological modifications are visible and only limited robustness gains are obtained.
Hydrogen Chloride Release From Combustion of Corn Straw in a Fixed Bed
Authors: Ren Xiaohan , Meng Xiaoxiao , Panahi Aidin , Rokni Emad , Sun Rui , Levendis Yiannis A.
Published: October 2017

Chlorine plays an important role in the slagging and corrosion of boilers that burn high-chlorine content biomass. This research investigated the emissions of hydrogen chloride (HCl) gas from combustion of biomass in a fixed bed, as functions of the mass air flow rate through the bed and of the moisture content of the fuel. The biomass burned was corn straw, either raw or torrefied. Results showed that increasing the air flow rate through the bed increased the release of HCl gas, as a result of enhanced combustion intensity and associated enhanced heat release rates. When the airflow through the bed was increased by a factor of six, the amount of fuel-bound chlorine converted to HCl nearly tripled. Upon completion of combustion, most of the chlorine remained in the biomass ashes, with the exception of the highest air flow case where the fraction of chlorine released in HCl equaled that captured in the ashes. HCl emissions from torrefied biomass were found to be lower than those from raw biomass. Finally, drying the biomass proved to be beneficial in drastically curtailing the generation of HCl gas.
A Vascular Access Port for Dialysis With a Polyurethane Foam Seal: A Pilot Study
Authors: Smith Robert E. , Docherty Nicole C. , Smith P. Alex , Maitland Duncan J. , Glowczwski Alan C.
Published: October 2017

End-Stage Renal Disease (ESRD) is a condition wherein the kidneys are incapable of removing toxins from the body. Over 660,000 Americans suffer from ESRD, with millions more in the early stages, known as chronic kidney disease [1]. The only cure for ESRD is a kidney transplant, but the majority of patients receive dialysis every 2–3 days to filter their blood while on the transplant waitlist.

Efficient dialysis requires approximately 600 mL/min of flow, which is commonly achieved by directly connecting an artery to a vein in the arm. Such a shunt may be created with an intervening prosthetic graft or by suturing the vein to the artery directly (termed an arteriovenous fistula, or AVF).

Though accepted as the gold standard, AVF’s may take >6 weeks to heal and become useable, and 35–50% will never become accessible [1]. Needle trauma to the AVF can weaken the vessel wall and produce aneurysms or hematomas, which leak blood, potentially causing infection or clotting off the AVF [2]. These complications are costly: hemodialysis patients on average cost Medicare over $84,000 per year, and Medicare is the primary payer for more than 80% of nearly 500,000 dialysis patients in the U.S. [1]. An improved dialysis access method is needed to address the clinical shortcomings and high costs associated with AVF’s.

A device has been developed to improve clinical outcomes and to reduce the failure rates associated with AVF’s. This device is a type of vascular access port which integrates with the external wall of the venous portion of the AVF, providing structural support to the vessel and preventing the types of trauma which lead to aneurysmal dilation or hematoma formation. The top and bottom sections are implanted independently within the patient’s soft tissue, allowing them to separate gradually as the AVF dilates during maturation. The result is a palpable and easy-to-access port which should improve AVF longevity (Figure 1).

Two unique design features were identified as key to the success of this vascular access port:

1. Type of membrane or seal

2. Proper tissue integration into the implant

This technical brief examines the selection of the proper membrane or seal on the port.