bluuebunny/crossref_metadata_2025 huggingface dataset:
Normative values for region‐specific colonic and gastrointestinal transit times in 111 healthy volunteers using the 3D‐Transit electromagnet tracking system: Influence of age, gender, and body mass index
Authors: Nandhra Gursharan Kaur , Mark Esben Bolvig , Di Tanna Gian Luca , Haase Anne‐Mette , Poulsen Jakob , Christodoulides Stephanos , Kung Victor , Klinge Mette W. , Knudsen Karoline , Borghammer Per , Andersen Katrine O. , Fynne Lotte , Sutter Nanna , Schlageter Vincent , Krogh Klaus , Drewes Asbjørn Mohr , Birch Malcolm , Scott S. Mark
Published: October 2019

Background

The 3D‐Transit electromagnet tracking system (Motilis Medica, SA, Lausanne, Switzerland) is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit and motility. Using this tool, we aimed to derive normative values for region‐specific colonic and GI transit times and to assess the influence of age, gender, and body mass index (BMI).

Methods

Regional and total colonic transit times (CTT), gastric emptying (GET), small intestinal (SITT), and whole gut (WGTT) transit times were extracted from 111 healthy volunteers from the United Kingdom and Denmark (58 female; median age: 40 years [range: 21‐88]). The effects of age, gender, and BMI were assessed using standard statistical methods.

Key Results

The ascending, transverse, descending, and rectosigmoid colon transit times accounted for 32%, 34%, 17%, and 17% of total CTT in females, and 33%, 25%, 14%, and 28% of total CTT in males. CTT and WGTT were seen to cluster at intervals separated by approximately 24 hours, providing further evidence of the non‐continuous nature of these measurements. Increasing age was associated with longer CTT (P = .021), WGTT (P < .001) ascending (P = .004), transverse (P < .001), and total right (P < .001) colon transit times, but shorter rectosigmoid (P = .004) transit time. Female gender was significantly associated with longer transverse (P = .049) and descending (P < .001) colon transit times, but shorter rectosigmoid (P < .001) transit time. Increasing BMI was significantly associated with shorter WGTT (P = .012).

Conclusions and Inferences

For the first time, normative reference values for region‐specific colonic transit have been presented. Age, gender, and BMI were seen to have an effect on transit times.
A transcription factor OsbHLH156 regulates Strategy II iron acquisition through localising IRO2 to the nucleus in rice
Authors: Wang Shoudong , Li Lin , Ying Yinghui , Wang Jin , Shao Ji Feng , Yamaji Naoki , Whelan James , Ma Jian Feng , Shou Huixia
Published: October 2019

Plants have evolved two strategies to acquire ferrous (Strategy I) or ferric (Strategy II) iron from soil. The iron‐related bHLH transcription factor 2 (IRO2) has been identified as a key regulator of iron acquisition (Strategy II) in rice. However, its mode of action, subcellular localisation and binding partners are not clearly defined.

Using RNA‐seq analyses, we identified a novel bHLH‐type transcription factor, OsbHLH156. The function of OsbHLH156 in Fe homeostasis was analysed by characterisation of the phenotypes, elemental content, transcriptome, interaction and subcellular localisation of OsbHLH156 and IRO2.

OsbHLH156 is primarily expressed in the roots and transcript abundance is greatly increased by Fe deficiency. Loss of function of OsbHLH156 resulted in Fe‐deficiency‐induced chlorosis and reduced Fe concentration in the shoots under upland or Fe(III) supplied conditions. Transcriptome analyses revealed that the expression of most Fe‐deficiency‐responsive genes involved in Strategy II were not induced in the osbhlh156‐1 mutant. Furthermore, OsbHLH156 was required for nuclear localisation of IRO2.

We conclude that OsbHLH156 is required for a Strategy II uptake mechanism in rice, partnering with a previously identified ‘master’ regulator IRO2. Mechanistically it is required for the nuclear localisation of IRO2.
Folate levels in pregnancy and offspring food allergy and eczema
Authors: Molloy John , Collier Fiona , Saffery Richard , Allen Katrina J. , Koplin Jennifer J. , Louise Ponsonby Anne , Tang Mimi L. K. , Ward Alister C. , Martino David , Burgner David , Carlin John B. , Ranganathan Sarath , Symeonedies Christos , Dwyer Terence ,   the BIS Investigator Group, Vuillermin Peter
Published: October 2019

Background

High folate status in pregnancy has been implicated in the increased prevalence of allergic disease, but there are no published data relating directly measured folate status in pregnancy to challenge‐proven food allergy among offspring. The study aim was to examine the association between red blood cell (RBC) folate status in trimester three of pregnancy and allergic disease among offspring.

Methods

Red blood cell folate levels were measured at 28‐32 weeks’ gestation in a prospective birth cohort (n = 1074). Food allergy outcomes were assessed in 1‐year‐old infants by skin prick testing and subsequent food challenge. Eczema was assessed by questionnaire and clinical review. High trimester three RBC folate was defined as greater than (>) 1360 nmol/L. Binomial regression was used to examine associations between trimester three RBC folate and allergic outcomes, adjusting for potential confounders.

Results

Red blood cell folate levels were measured in 88% (894/1064) of pregnant women. The mean concentration was 1695.6 nmol/L (standard deviation 415.4) with 82% (731/894) >1360 nmol/L. There was no evidence of either linear or non‐linear relationships between trimester three RBC folate and allergic outcomes, nor evidence of associations between high RBC folate and food allergy (adjusted risk ratio (aRR) 2.89, 95% CI 0.90‐9.35), food sensitization (aRR 1.72, 95% CI 0.85‐3.49), or eczema (aRR 0.97, 95% CI 0.67‐1.38).

Conclusion

The majority of pregnant women in this study had high RBC folate levels. There was no evidence of associations between trimester three RBC folate and food allergy, food sensitization, or eczema among the offspring, although larger studies are required.
The Role of Inclusive Innovation in Promoting Social Sustainability
Authors: Kalkanci Başak , Rahmani Morvarid , Toktay L. Beril
Published: October 2019

This special issue implores us to address sustainability from the lens of emerging economies and the role that innovation can play in this context. We posit that, for sustainable operations research to be relevant in the context of emerging economies, it needs to incorporate social concerns and conditions of underserved populations, with an emphasis on inclusion and equity. Especially important for addressing social concerns of these populations will be product/service innovation, process/business model innovation, and supply chain innovation. We further posit that successful innovation in these areas will require collaboration of for‐profit firms with the public sector, civil society organizations, and communities. In thisstudy, we put forward “inclusive innovation” as a unifying approach that enables the collaborative integration of social issues of relevance to underserved populations in operations management decisions. We then focus on contemporary sectoral challenges in services, manufacturing, and agriculture, highlight the relevant social sustainability issues with an emphasis on those relevant to underserved populations, and point to new opportunities for research.
Morphological and morphometric characterization of domestic cat epididymal sperm
Authors: de Sousa Barbosa Brenna , Rodrigues Silva Herlon Victor , Evaristo de Almeida Tabosa Beatriz , Gothardo Pereira Nunes Thalles , de Magalhães Francisco Felipe , Daniel Machado da Silva Lúcia
Published: October 2019

Sperm morphometry is the tool that confers objectivity to the morphological evaluation by accurately measuring the dimensions of the gamete and its structures. Thus, the aim of the study was to perform a morphometric characterization of the domestic cat sperm. Therefore, sperm samples were collected from twenty pairs of epididymis in a TRIS extender at 37ºC. An aliquot of the sample was used to make a smear with Rose Bengal solution, and afterwards, the morphology and morphometry were analysed. In the morphology, were quantified the percentage of normal sperm cells, morphological changes of head, midpiece and tail. In morphometry, each normal sperm cell was measured for length, width, area and perimeter of head and midpiece, tail length and total length. The parameters ellipticity, elongation, regularity and rugosity were also determined. The percentage of normal sperm was 67.21%. Of the abnormalities, the curled/folded tail, followed by the curved midpiece, abnormal shaped head and detached head were the most quantified. The sperm head presented 5.56 ± 0.01 μm and 3.10 ± 0.01 μm of length and width, respectively. The head area was 16.94 ± 0.05 μm2, while the perimeter was 16.16 ± 0.03 μm. In the derived parameters, the values were as follows: ellipticity of 1.81 ± 0.00; elongation of 21.39 ± 0.12; regularity of 0.81 ± 0.00; and rugosity of 0.14 ± 0.00. The midpiece presented length and width of 7.96 ± 0.01 μm and 0.76 ± 0.01 μm, respectively. The mean length of the sperm tail was 45.12 ± 0.06 μm, and the total cell size was 58.67 ± 0.06 μm. Thus, it was concluded that the cat sperm is an elongated cell, with high rugosity and regularity. The spermatic tail represents more than ¾ of the total length of the cell and the midpiece exceeds the length of the head.
Mega‐monsoon variability during the late Triassic: Re‐assessing the role of orbital forcing in the deposition of playa sediments in the Germanic Basin
Authors: Bahr André , Kolber Gilles , Kaboth‐Bahr Stefanie , Reinhardt Lutz , Friedrich Oliver , Pross Jörg
Published: October 2019

The formation of the supercontinent Pangaea during the Permo–Triassic gave rise to an extreme monsoonal climate (often termed ‘mega‐monsoon’) that has been documented by numerous palaeo‐records. However, considerable debate exists about the role of orbital forcing in causing humid intervals in an otherwise arid climate. To shed new light on the forcing of monsoonal variability in subtropical Pangaea, this study focuses on sediment facies and colour variability of playa and alluvial fan deposits in an outcrop from the late Carnian (ca225 Ma) in the southern Germanic Basin, south‐western Germany. The sediments were deposited against a background of increasingly arid conditions following the humid Carnian Pluvial Event (ca234 to 232 Ma). Theca2·4 Myr long sedimentary succession studied shows a tripartite long‐term evolution, starting with a distal mud‐flat facies deposited under arid conditions. This phase was followed by a highly variable playa‐lake environment that documents more humid conditions and finally a regression of the playa‐lake due to a return of arid conditions. The red–green (a*) and lightness (L*) records show that this long‐term variability was overprinted by alternating wet/dry cycles driven by orbital precession andca405 kyr eccentricity, without significant influence of obliquity. The absence of obliquity in this record indicates that high‐latitude forcing played only a minor role in the southern Germanic Basin during the late Carnian. This is different from the subsequent Norian when high‐latitude signals became more pronounced, potentially related to the northward drift of the Germanic Basin. The recurring pattern of pluvial events during the late Triassic demonstrates that orbital forcing, in particular eccentricity, stimulated the occurrence and intensity of wet phases. It also highlights the possibility that the Carnian Pluvial Event, although most likely triggered by enhanced volcanic activity, may also have been modified by an orbital stimulus.
Retracted: The Three‐Step Theory of Suicide: An Independent Replication and Conceptual Extension
Authors: Hagan Christopher R. , Muehlenkamp Jennifer J.
Published: October 2019

Retraction: Christopher R. Hagan PhD, Jennifer J. Muehlenkamp PhD, “The Three‐Step Theory of Suicide: An Independent Replication and Conceptual Extension,” Suicide and Life‐Threatening Behavior, Wiley, © American Association of Suicidology

The above article, published online on 30 September 2019 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, Thomas Joiner, PhD, and John Wiley and Sons Ltd. The retraction has been agreed due to errors in variable calculation and a post‐publication reviewer's concerns that some analyses did not accurately test the theoretical model. An updated version of this article will soon undergo review for publication at Suicide and Life‐Threatening Behavior, and if accepted for publication, will be accompanied by an editorial from the Editor‐in‐Chief.
Examining the influences of air quality in China's cities using multi‐scale geographically weighted regression
Authors: Fotheringham A. Stewart , Yue Han , Li Ziqi
Published: October 2019

This study evaluates the influences of air pollution in China using a recently proposed model—multi‐scale geographically weighted regression (MGWR). First, we review previous research on the determinants of air quality. Then, we explain the MGWR model, together with two global models: ordinary least squares (OLS) and OLS containing a spatial lag variable (OLSL) and a commonly used local model: geographically weighted regression (GWR). To detect and account for any variation of the spatial autocorrelation of air pollution over space, we construct two extra local models which we call GWR with lagged dependent variable (GWRL) and MGWR with lagged dependent variable (MGWRL) by including the lagged form of the dependent variable in the GWR model and the MGWR model, respectively. The performances of these six models are comprehensively examined and the MGWR and MGWRL models outperform the two global models as well as the GWR and GWRL models. MGWRL is the most accurate model in terms of replicating the observed air quality index (AQI) values and removing residual dependency. The superiority of the MGWR framework over the GWR framework is demonstrated—GWR can only produce a single optimized bandwidth, while MGWR provides covariate‐specific optimized bandwidths which indicate the different spatial scales that different processes operate.
Degradation of the transcription factors PIF4 and PIF5 under UV‐B promotes UVR8‐mediated inhibition of hypocotyl growth in Arabidopsis
Authors: Tavridou Eleni , Pireyre Marie , Ulm Roman
Published: October 2019

Inhibition of hypocotyl growth is a well‐established UV‐B‐induced photomorphogenic response that is mediated by the UV‐B photoreceptor UV RESISTANCE LOCUS 8 (UVR8). However, the molecular mechanism by which UVR8 signaling triggers inhibition of hypocotyl growth is poorly understood. The bZIP protein ELONGATED HYPOCOTYL 5 (HY5) functions as the main positive regulatory transcription factor in the UVR8 signaling pathway, with HY5‐HOMOLOG (HYH) playing a minor role. However, here we demonstrate that hy5 hyh double mutants maintain significant UVR8‐dependent hypocotyl growth inhibition. We identify UVR8‐dependent inhibition of the activities of bHLH transcription factors PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5 as part of the UVR8 signaling pathway, which results in inhibition of hypocotyl growth. The UVR8‐mediated repression of several hypocotyl elongation‐related genes is independent of HY5 and HYH but largely associated with UVR8‐dependent degradation of PIF4 and PIF5, a process that consequently diminishes PIF4/5 target promoter occupancy. Taken together, our data indicate that UVR8‐mediated inhibition of hypocotyl growth involves degradation of PIF4 and PIF5. These findings contribute to our mechanistic understanding of UVR8‐induced photomorphogenesis and further support the function of PIFs as integrators of different photoreceptor signaling pathways.
Past, present, and future: a qualitative and literature study identifying historical trends, drivers, and transformational factors for the future demand of blood supply in the Netherlands
Authors: Langi Sasongko Praiseldy , Rolink Marlon , van den Hurk Katja , van Kraaij Marian , Janssen Mart
Published: October 2019

BACKGROUND

As blood transfusion has evolved, there is a need to understand its historical trends and underlying drivers. Furthermore, for blood bank management to make decisions about the future, they need to consider what transformational factors (defined as developments in science, society, and technology) could significantly impact blood demand and to what effect. This study has a two‐fold aim: to explore transfusion experts' perspectives regarding 1) historical trends and drivers of red blood cells (RBCs) in the past 20 years and 2) transformational factors that would impact the future demand of RBCs and to what effect.

STUDY DESIGN AND METHODS

Forty‐two semi‐structured interviews were held with transfusion experts from the Netherlands and abroad, supplemented with a literature review of Pubmed, Google Scholar, and gray literature.

RESULTS

With regard to historical trends and drivers, experts shared two main trends: decreased or increased demands for RBCs. Various drivers were reported for each trend, coupled with evidence from literature. With regard to the future, experts anticipated that RBC demands will either increase (17%), decrease (45%), decrease but stabilize (12%), or stabilize as is (7%). Various transformational factors were found to support each trend (e.g., gene therapy will reduce RBC demand), although there were factors for which experts were unsure about its effects (e.g., cultured RBCs). Seven groups of transformation factors were identified in the literature review.

CONCLUSION

While the future of blood transfusion is uncertain, there are actions that blood banks may take now to prepare for potential future developments.
Input trade liberalisation, institution and markup: Evidence from China's accession to the WTO
Authors: Mao Qilin , Xu Jiayun
Published: October 2019

This paper investigates the effects of input trade liberalisation on firm markups and assesses how institutional environment affects such impacts by using Chinese firm‐level data. To identify the causal effects, we exploit the quasi‐natural experiment of China's WTO accession in 2001 and perform difference‐in‐differences estimation. The results show that input tariff liberalisation leads to a substantial increase in firm markups, and institutional environment significantly strengthens such an impact. We further uncover the underlying mechanisms through which input tariff liberalisation boosts firm markups, and show that both price and cost channels work for the input tariff cut effect on firm markups, of which the latter is much more important. In addition, we also demonstrate that input tariff cut significantly fosters aggregate markup growth, and the reallocation effect is found to be an important channel through which input tariff liberalisation boosts aggregate markup growth.
Streptococcus canis multilocus sequence typing in a case series of dogs with ulcerative keratitis
Authors: Enache Andra E. , Mitchell Catriona , Kafarnik Christiane , Waller Andrew S.
Published: October 2019

Objective

To determine whether four isolates of Streptococcus canis (S canis) recovered from dogs diagnosed with ulcerative keratitis at the Animal Health Trust (AHT) were genetically related to other ocular isolates that are registered in the online database.

Animal studied

Four S canis corneal isolates.

Procedures

Clinical and laboratory records between 2016 and 2017 were searched for dogs with ulcerative keratitis for which microbiology analysis was consistent with the growth of S canis. Genomic DNA was extracted for sequencing (Illumina MiSeq), and multilocus sequence types (STs) were determined using MLST 1.8 relative to the 44 sequence types of S canis available. A neighbor‐joining tree was constructed in MEGA v4.0. A two‐sided Fisher's exact test was used to determine any associations between the isolated strains and ocular infections of dogs.

Results

Four strains were isolated from pugs (cases 1‐4) with ulcerative keratitis. Genome sequencing identified ST‐27 (case 1), ST‐9 (case 3), and ST‐13 (cases 2 and 4). STs 13 and 27 are members of Clonal Complex (CC)‐13. Analysis of the multilocus sequence typing database revealed that CC‐13 strains accounted for six of the twelve isolates recovered from the eye exudates of dogs (P = .0078).

Conclusions

There is early evidence that the CC‐13 group of S canis is associated with ocular infections in dogs. We provide draft genome sequences toward the future identification of virulence mechanisms associated with streptococcal keratitis in dogs.
Editorial
Authors: Cano Gutiérrez Carlos Alberto
Published: October 2019

El envejecimiento poblacional es uno de los temas de mayor actualidad, pues tiene implicaciones en múltiples escenarios como en el económico, en el político, en nuestro entorno y, por supuesto, en la salud. Dicha situación no es en vano, pues cerca del 12 % de la población colombiana tiene 60 o más años, con un incremento acelerado, pues esta crece al 3,5 % en comparación con el país, que lo hace al 1,7 % (1). El índice de envejecimiento pasó de 11,6 % en 1951, al 49,8 % en la actualidad, con un aumento de la expectativa de vida al nacer de 30 años en los últimos 70 años, llegando los 79 años en las mujeres y 73 años en los hombres (1), fenómeno nunca antes visto en nuestro país.
Lesión quística testicular en un lactante: consideraciones diagnósticas y terapéuticas
Authors: González Villarreal Laura Camila , Escobar Rivera Fernando Augusto , Aljure Reales Vicente De Jesús
Published: October 2019

Introducción: Los tumores testiculares prepuberales suelen ser benignos. Las lesiones quísticas constituyen un amplio diagnóstico diferencial de las masas benignas escrotales en niños. Una adecuada evaluación incluye el examen clínico, la ecografía Doppler y la medición de marcadores tumorales. Ante una fuerte sospecha clínica y radiológica de benignidad, el tratamiento de elección es la enucleación con preservación del parénquima. Objetivo: Describir el caso de un lactante con una masa quística de testículo compatible con quiste epidermoide. Discutir los aspectos clínicos, imagenológicos y terapéuticos más relevantes de las lesiones testiculares prepuberales. Presentación del caso: Un lactante ingresa por identificación de una masa testicular circunscrita no dolorosa de 1 cm de diámetro. La ecografía demuestra un quiste simple intraparenquimatoso y los marcadores tumorales son negativos. Se realiza enucleación por vía escrotal, sin complicaciones. El estudio histopatológico es compatible con un quiste epidermoide. Hubo seguimiento a 3 años sin recidiva ni atrofia testicular. Discusión y conclusión: Teniendo en cuenta que la mayoría de los tumores prepuberales de testículo son benignos, la cirugía conservadora puede considerarse una alternativa terapéutica ante una lesión circunscrita, pequeña, avascular, con marcadores tumorales negativos.
Kairós doloroso y aburrimiento: esperar por el preciso momento
Authors: Padilla-Teruel Reynaldo
Published: October 2019

En este artículo se reflexiona sobre el fenómeno de la espera, interpretado en nuestro propio contexto, pero a partir de un texto de Heidegger. En el mismo se implica que el aburrido espera por el preciso momento de algo de lo cual presume que disipará su aburrimiento. Se procederá a mostrar la estructura interna del tiempo-experiencia del fenómeno de la espera que se experimenta cuando estamos aburridos y cómo el devenir de este tiempo se configura existencialmente en dolor. Para ello, se indagará fenomenológicamente la estructura temporal de tal espera, indicando así cómo dicha estructura transforma la existencia de quien espera aburridamente.
Dynamic Mode Decomposition Analysis of Flow Separation in a Diffuser to Inform Flow Control Strategies
Authors: Wang Jinchun , Huang Guoping , Lu Weiyu , Sullivan Pierre E.
Published: October 2019

In this work, a large eddy simulation (LES) of a typical subsonic diffuser provides data used to analyze coherent structure in a separated flow with dynamic mode decomposition (DMD). From this, a low–dimensional approximation, which retains the main dynamic characteristics of the original flow fields, is obtained. In particular, specific dynamic structures associated with a unique frequency are isolated. The spatial structures of the real and imaginary parts of the DMD mode are similar but with a phase difference. The contribution of the conjugate modes to the evolution of the DMD modes over time is discussed. The dominant frequency is found to be related to the wake mode. The scale of wake will saturate, and the shear layer will become weaker and merges into the wake structure as it develops downstream. This allows direction for effective flow control strategies using this information.
Energy Efficient Control of Parallel Variable-Frequency Pumps in Magnetic Water-Cooling System
Authors: Qiu Wenjun , Ouyang Zhengrong
Published: October 2019

This paper presents an optimal control method for the prediction of parallel centrifugal variable frequency pump performance in any conditions to maximize the total efficiency of the pump system, thereby minimizing energy consumption. First, a theoretical model of parallel water pumping set was established, after which the shaft power model was setup specifically for the off-rating conditions. By combining the typical polynomial fitting method of the efficiency and the shaft power model we brought up, a new optimized control method was proposed. Using this method, the complex optimization task was solved with the optimal control of the operating number selection and speed ratios for parallel variable speed pumps based on the decision-making. The proposed method was subsequently applied to the pumping set of the water-cooling system in High Magnetic Field Facility. The practical testing results of the proposed method showed its superiority over both the primitive and the previous optimal methods, by considerably lowering the power consumption and accurately calculating the performance parameters in any conditions. The method has universality and simplicity for online implementation, which provides a reference for the control methods of parallel centrifugal pumps in variable flow systems with a differential pressure control strategy.
Optimization of Flow Control Parameters Over SD7003 Airfoil With Synthetic Jet Actuator
Authors: Tadjfar M. , Kamari Dj.
Published: October 2019

An optimization study was conducted to find the optimum operational characteristics of a synthetic jet actuator (SJA) to postpone the static stall separation over an SD7003 airfoil at Reynolds number of 60,000. A genetic algorithm (GA) coupled with an artificial neural network (ANN) was employed. Aerodynamic performance (L/D) was chosen as the objective function. Both tangent to the boundary layer (TBL) and the cross to the boundary layer (CBL) configurations of SJA were used and their effectiveness in separation control were compared. The following design variables of the SJA were allowed to change within a predetermined range: location, the opening length, the injection velocity amplitude, the injection angle, and the nondimensional frequency. It was found that for location, opening length, and velocity amplitude ratio, a narrow range near the peak optimum values achieved the best performance. However, for the nondimensional frequency and jet injection angle, the optimum values providing highest performance were in a wider range of values. Activation of SJ actuator improved the aerodynamic performance of the airfoil significantly. However, TBL configuration of SJA produced superior improvement in aerodynamic performance. The optimum aerodynamic performance achieved by TBL-SJA was 34.4, in comparison to 25.3 for CBL-SJA and 5 for the uncontrolled stalled airfoil at 13 deg angle of attack.
Prediction of Premixed Flame Dynamics Using Large Eddy Simulation With Tabulated Chemistry and Eulerian Stochastic Fields
Authors: Avdonin Alexander , Javareshkian Alireza , Polifke Wolfgang
Published: October 2019

This paper demonstrates that a large Eddy simulation (LES) combustion model based on tabulated chemistry and Eulerian stochastic fields can successfully describe the flame dynamics of a premixed turbulent swirl flame. The combustion chemistry is tabulated from one-dimensional burner-stabilized flamelet computations in dependence on progress variable and enthalpy. The progress variable allows to efficiently include a detailed reaction scheme, while the dependence on enthalpy describes the effect of heat losses on the reaction rate. The turbulence-chemistry interaction is modeled by eight Eulerian stochastic fields. An LES of a premixed swirl burner with a broadband velocity excitation is performed to investigate the flame dynamics, i.e., the response of heat release rate to upstream velocity perturbations. In particular, the flame impulse response and the flame transfer function (FTF) are identified from LES time series data. Simulation results for a range of power ratings are in good agreement with the experimental data.
Experimental and Numerical Investigation of Small-Scale Tesla Turbines
Authors: Renuke Avinash , Vannoni Alberto , Pascenti Matteo , Traverso Alberto
Published: October 2019

Interest in small-scale turbines is growing mainly for small-scale power generation and energy harvesting. Conventional bladed turbines impose manufacturing limitations and higher cost, which hinder their implementation at small scale. This paper focuses on experimental and numerical performance investigation of Tesla type turbines for micro power generation. A flexible test rig for Tesla turbine fed with air as working fluid has been developed, of about 100 W net mechanical power, with modular design of two convergent-divergent nozzles to get subsonic as well as supersonic flow at the exit. Seals are incorporated at the end disks to minimize leakage flow. Extensive experiments are done by varying design parameters such as disk thickness, gap between disks, radius ratio, and outlet area of exhaust with speeds ranging from 10,000 rpm to 40,000 rpm. A quasi-one-dimensional (1D) model of the whole setup is created and tuned with experimental data to capture the overall performance. Major losses, ventilation losses at end disks, and nozzle and exhaust losses are evaluated experimentally and numerically. Effect of design parameters on the performance of Tesla turbines is discussed.
Poroelastic Effects on the Time- and Rate-Dependent Fracture of Polymer Gels
Authors: Yu Yalin , Bouklas Nikolaos , Landis Chad M. , Huang Rui
Published: October 2019

Fracture of polymer gels is often time- and rate-dependent. Subject to a constant load, a gel specimen may fracture immediately or after a delay (time-dependent, delayed fracture). When a crack grows in a gel, the fracture energy may depend on the crack speed (rate-dependent). The underlying mechanisms for the time- and rate-dependent fracture of gels could include local molecular processes, polymer viscoelasticity, and solvent diffusion coupled with deformation (poroelasticity). This paper focuses on the effects of poroelasticity. A path-independent, modified J-integral approach is adopted to define the crack-tip energy release rate as the energetic driving force for crack growth in gels, taking into account the energy dissipation by solvent diffusion. For a stationary crack, the energy release rate is time-dependent, with which delayed fracture can be predicted based on a Griffith-like fracture criterion. For steady-state crack growth in a long-strip specimen, the energy release rate is a function of the crack speed, with rate-dependent poroelastic toughening. With a poroelastic cohesive zone model, solvent diffusion within the cohesive zone leads to significantly enhanced poroelastic toughening as the crack speed increases, rendering a rate-dependent traction-separation relation. While most of the results are based on a linear poroelastic formulation, future studies may extend to nonlinear theories with large deformation. In addition to the poroelastic effects, other mechanisms such as viscoelasticity and local fracture processes should be studied to further understand the time and rate-dependent fracture of polymer gels.
Effects of Fuel Staging on the Hydrodynamic Stability of Multinozzle Swirl Flows
Authors: Gupta Saarthak , Manoharan Kiran , Hemchandra Santosh
Published: October 2019

Hydrodynamic instability in lean premixed gas turbine combustors can cause coherent flow velocity oscillations. These can in turn drive heat release oscillations that when favorably coupled with combustor acoustic modes can result in combustion instability. The aim of this paper is to understand the impact of fuel staging on the characteristics of hydrodynamic modes in multinozzle combustors. We extend our recent numerical study on the hydrodynamic stability characteristics of a multinozzle combustor having three nozzles in a straight line with uniform fuel–air ratio in each nozzle, to the nonuniform fuel–air ratio case. As before, we construct the base flow model for this study by superposing contributions from individual nozzles, determined using a base flow model for a nominally axisymmetric single nozzle, at every point in the computational domain. The impact of fuel staging is captured by changing the burnt to unburnt gas density ratio parameter in the individual contribution from each nozzle. We investigate the characteristics of the most locally absolutely unstable mode for two cases. The first one is when the middle nozzle is made fuel rich when compared to the side nozzles and the second is when the side nozzles are made fuel rich relative to the middle nozzle. The impact of nonuniform fuel/air ratio on the local absolutely unstable temporal eigenvalues is seen to be small. However, significant changes in the spatial structure of the flow oscillations associated with the hydrodynamic eigenmodes are observed. In the first case, the flow oscillations with a different locally azimuthal nature on the middle nozzle when compared to the side nozzles emerge as the middle nozzle is made richer. In the second case, the oscillations on the two side nozzles are suppressed leaving the middle nozzle in a state that closely matches that of a single unconfined nozzle with the same nominal base flow velocity field. These types of internozzle variations in flow oscillation characteristics can explain the emergence of nonuniformity in heat release oscillation characteristics between individual nozzles in multinozzle combustors.
On Piping Vibration Screening Criteria
Authors: Jacimovic Nikola , D'Agaro Fabio
Published: October 2019

Vibration-related issues are common in the engineering practice. Piping vibrations can range from those barely noticeable to the ones which result in total system failure in a very short time . This paper presents a synthesis of the criteria which should be used to estimate the severity of vibrations based on both exhaustive literature research and the authors' experience accumulated over the years of engineering practice.
Design of Compressed Natural Gas Pressure Vessel (Type II) to Improve Storage Efficiency and Structural Reliability
Authors: Kwak Hyo Seo , Park Gun Young , Kim Chul
Published: October 2019

Type II storage vessel, which consists of a metallic liner hoop wrapped with a carbon fiber-resin composite to work at high pressure, has been widely adopted as the fuel container for compressed natural gas (CNG) vehicles. The general vessel, manufactured by welding enclosures to an open-end cylinder, shows uniform thickness throughout the whole liner, while the high pressure vessel, fabricated by the deep drawing and ironing (D.D.I) and spinning processes, has the integral junction part of cylinder with increased end thickness along the meridian direction. This study established a design method for improvement of failure resistance and inner capacity of the seamless CNG pressure vessel (Type II) through finite element analysis with consideration of thickness variation. Autofrettage pressure is used to enhance fracture performance and fatigue life of the vessel, and variations of stress behaviors in the liner and composite were analyzed during the autofrettage process. The influence of the composite on generation of compressive residual stress was investigated. In order to verify advantages of the D. D. I. and the spinning processes for structural safety at the end closure, the stress distribution considering thickness variation was compared with that with uniform thickness, and the maximum inner capacity objective satisfying structural reliability was obtained. The inner capacity of the proposed model with the ratio of major axis to minor axis, 2.2, was expanded by 4.5. Theoretical equivalent stresses were compared with those from the simulations, and the technique of FEM was verified.
A Lumped-Mass Model for Large Deformation Continuum Surfaces Actuated by Continuum Robotic Arms
Authors: Habibi Hossein , Yang Chenghao , Godage Isuru S. , Kang Rongjie , Walker Ian D. , Branson David T.
Published: October 2019

Currently, flexible surfaces enabled to be actuated by robotic arms are experiencing high interest and demand for robotic applications in various areas such as healthcare, automotive, aerospace, and manufacturing. However, their design and control thus far has largely been based on “trial and error” methods requiring multiple trials and/or high levels of user specialization. Robust methods to realize flexible surfaces with the ability to deform into large curvatures therefore require a reliable, validated model that takes into account many physical and mechanical properties including elasticity, material characteristics, gravity, external forces, and thickness shear effects. The derivation of such a model would then enable the further development of predictive-based control methods for flexible robotic surfaces. This paper presents a lumped-mass model for flexible surfaces undergoing large deformation due to actuation by continuum robotic arms. The resulting model includes mechanical and physical properties for both the surface and actuation elements to predict deformation in multiple curvature directions and actuation configurations. The model is validated against an experimental system where measured displacements between the experimental and modeling results showed considerable agreement with a mean error magnitude of about 1% of the length of the surface at the final deformed shapes.
Foldable Hexagonal Structures Based on the Threefold-Symmetric Bricard Linkage
Authors: Yang Fufu , You Zhong , Chen Yan
Published: October 2019

The threefold-symmetric Bricard linkage, a special type of Bricard linkage, is able to generate spatial motion in 3D space with well-defined threefold rotational symmetries and three symmetric planes, which makes it a robust base linkage in designing many one-degrees-of-freedom (DOF) foldable structures. However, its practical applications are limited, as the design method with the consideration of the actual assembly is still an ambiguous area. In this paper, a foldable hexagonal structure based on the alternative form of the threefold-symmetric Bricard linkage is designed and manufactured. Geometric conditions for achieving the desired deployment are analyzed at first. Then the relationship among kinematic variables of the linkage and the geometric parameters of physical bars with a regular triangular cross-section are set up. Finally, an intuitive approach is presented to detect two types of physical blockages in the motion paths of deployment. The proposed method supplies a convenient way to design foldable hexagonal structures for potential practical applications.
Simulation of Brain Response to Noncontact Impacts Using Coupled Eulerian–Lagrangian Method
Authors: Na Miao , Beavers Timothy J. , Chandra Abhijit , Bentil Sarah A.
Published: October 2019

Finite element (FE) method has been widely used for gaining insights into the mechanical response of brain tissue during impacts. In this study, a coupled Eulerian−Lagrangian (CEL) formulation is implemented in impact simulations of a head system to overcome the mesh distortion difficulties due to large deformation in the cerebrospinal fluid (CSF) region and provide a biofidelic model of the interaction between the brain and skull. The head system used in our FE model is constructed from the transverse section of the human brain, with CSF modeled by Eulerian elements. Spring connectors are applied to represent the pia-arachnoid connection between the brain and skull. Validations of the CEL formulation and the FE model are performed using the experimental results. The dynamic response of brain tissue under noncontact impacts and the brain regions susceptible to injury are evaluated based on the intracranial pressure (ICP), maximum principal strain (MPS), and von Mises stress. While tracking the critical MPS location on the brain, higher likelihood of contrecoup injury than coup injury is found when sudden brain−skull motion takes place. The accumulation effect of CSF in the ventricle system, under large relative brain−skull motion, is also identified. The FE results show that adding relative angular velocities, to the translational impact model, not only causes a diffuse high strain area, but also cause the temporal lobes to be susceptible to cerebral contusions since the protecting CSF is prone to be squeezed away at the temporal sites due to the head rotations.
Wire Vibration Modeling and Experimental Analysis for Wire Saw Machining
Authors: Tang Aofei , Li Shujuan , Yang Guigeng , Li Lun , Landers Robert G.
Published: October 2019

Surface roughness is the key index point of wire saw processing silicon carbide (SiC). Many factors influence wafer surface quality, which is determined by the motion of the wire relative to the part. The vibration characteristic of wire saw and the process parameters are concerned factors in this paper, which presents a wire vibration model to study the wire saw vibration law. Experimental studies of a stationary wire are conducted to calibrate the damping coefficient and experimental studies of a moving wire are used to validate the developed model. Simulation, theoretical, and experimental data for wire vibrations during a variety of machining processes are found to compare very well, and the effects of various wire saw process parameters are investigated to analyze the influences of process parameters on wire vibration. It was shown that increasing the wire tension and feed rate, or decreeing the wire length, decreases the wire's first dominant frequency, and that changes in the wire velocity had a negligible effect. Finally, the measurement of the surface morphology and wire saw vibrations for different processing parameters was conducted, and it was seen that increases in the wire velocity and wire tension increases part surface quality and decreases processing time, while an increase in the feed rate decreases both part surface quality and processing time. The results show a clear correlation between the amplitude of the wire vibration outside of the processing zone and the part surface quality.
The Reliability and Validity of the Turkish Kaiser Physical Activity Survey for Pregnant Women
Authors: Uzelpasaci Esra , Akbayrak Türkan , Özgül Serap , Orhan Ceren , Baran Emine , Nakip Gülbala , Beksac Sinan , Topuz Semra
Published: October 2019

Background: Evaluation of physical activity by condition-specific surveys provides more accurate results than generic physical activity questionnaires. The aim of this study was to investigate the reliability and validity of the Kaiser Physical Activity Survey (KPAS) in Turkish pregnant women. Methods: In the translation and cultural adaptation of the KPAS, the 6-phase guidelines recommended in the literature were followed. The study included a total of 151 pregnant women who were assessed using the Turkish version of KPAS, the Pregnancy Physical Activity Questionnaire, and the SenseWear Pro3 Armband. To determine the test–retest reliability, the KPAS was reapplied after 7 days. The psychometric properties of KPAS were analyzed with respect to internal consistency, test–retest reliability, and concurrent validity. Results: Cronbach α coefficient indicating the internal consistency of the Turkish KPAS was found to be .60 to .80, showing moderate reliability. The intraclass correlation coefficient for test–retest reliability was very strong (intraclass correlation coefficient: .96–.98). The total KPAS scores were found to be moderately correlated with the total Pregnancy Physical Activity Questionnaire score and the total energy expenditure value on the SenseWear Pro3 Armband. Conclusions: This study showed that KPAS is a valid and reliable instrument for evaluating physical activity in Turkish pregnant women in different aspects.
Stress, age, and cancer
Authors: Ferrarelli Leslie K.
Published: October 2019

Stress and advanced age suppress interferon-mediated antitumor immune surveillance and therapy.
Demonstration of the Broad-Spectrum
In Vitro
Activity of Finafloxacin against Pathogens of Biodefense Interest
Authors: Barnes Kay B. , Zumbrun Steven D. , Halasohoris Stephanie A. , Desai Purvi D. , Miller Lynda L. , Richards Mark I. , Russell Paul , Bentley Christine , Harding Sarah V.
Published: October 2019

This study investigated the
in vitro
activity of finafloxacin against bacterial strain panels of the biodefense pathogens. Broth microdilution assays were performed at neutral and acidic pH to determine the effectiveness of the antibiotics under conditions typical of an intracellular environment. In all instances, finafloxacin demonstrated superior activity at low pH.
Colistin Resistance-Mediated Bacterial Surface Modification Sensitizes Phage Infection
Authors: Hao Guijuan , Chen Annie I. , Liu Ming , Zhou Haijian , Egan Marisa , Yang Xiaoman , Kan Biao , Wang Hui , Goulian Mark , Zhu Jun
Published: October 2019

Colistin is a drug of last resort for the treatment of many multidrug-resistant Gram-negative bacteria, including carbapenem-resistant
Klebsiella pneumoniae
(CRKP). However, bacteria readily acquire resistance to this antibiotic via lipopolysaccharide modifications caused by spontaneous mutations or from enzymes acquired by lateral gene transfer. The fitness cost associated with these modifications remains poorly understood.
Persistence and Decay of Fecal Microbiota in Aquatic Habitats
Authors: Korajkic Asja , Wanjugi Pauline , Brooks Lauren , Cao Yiping , Harwood Valerie J.
Published: October 2019

Fecal microorganisms can enter water bodies in diverse ways, including runoff, sewage discharge, and direct fecal deposition. Once in water, the microorganisms experience conditions that are very different from intestinal habitats. The transition from host to aquatic environment may lead to rapid inactivation, some degree of persistence, or growth. Microorganisms may remain planktonic, be deposited in sediment, wash up on beaches, or attach to aquatic vegetation.