bluuebunny/crossref_metadata_2025 huggingface dataset:
Information Provision and Pricing in the Presence of Consumer Search Costs
Authors: Liu Yan , Cooper William L. , Wang Zizhuo
Published: February 2019

Should a seller make information about its products readily accessible to customers, so that customers do not have to incur any substantive cost—in terms of time and effort—to learn about those products? To help answer this question, we consider a monopolist selling two substitute products to a population of customers, who have differing tastes about the products. Each customer a priori has uncertainty about whether or not he will like each of the products. The seller may choose to make product information easily accessible, thereby allowing customers to resolve their uncertainties for free. Otherwise, customers may conduct research to resolve their uncertainties by incurring a search cost before making purchase decisions. We consider three “information structures” differing in whether the seller makes information about the products freely accessible or not. Our primary objective is to determine which structure gives the seller the highest revenue, while accounting for the seller’s pricing decisions as well as the induced customer responses to both the information structure and prices. We find that if each customer’s uncertainties are small in magnitude but highly positively correlated, then withholding both products’ information is the best for the seller. If the uncertainties are small in magnitude and negatively correlated, then providing one product’s information but not the other’s is the best. If the uncertainties are large in magnitude and positively correlated, then providing both products’ information is the best. We also show that when the correlation is negative, withholding both products’ information cannot be optimal. In addition, we also analyze various extensions of the model. These include a variant in which customers’ research is imperfect and may yield incorrect information to the customers, and a variant in which each customer’s uncertainty about a product can be decomposed into multiple uncertainties associated with individual attributes of the product.
Behaviors and Performance Improvement in a Vendor‐Managed Inventory Program: An Experimental Study
Authors: Zhao Xiaobo , Si Dezhen , Zhu Wanshan , Xie Jinxing , Shen Zuo‐Jun (Max)
Published: February 2019

Although vendor‐managed inventory (VMI) programs have gained popularity in practice, some empirical studies report that their implementations have not been successful. We conduct experiments to investigate behaviors in a supply chain where a supplier replenishes inventories for a retailer according to a VMI program under a revenue‐sharing contract. The results show that subjects’ decisions deviate significantly from the standard theoretical predictions because the retailer presents equality preference with adjustment, and the supplier exhibits fairness concern. Since the supplier bears not only the production cost, but also the risk of leftover inventory in the VMI program, we propose an approach that provides the retailer with an opportunity to voluntarily compensate the supplier with an additional percentage of revenue after demand realization. Experimental results based on this new operational procedure show that the retailer still presents equality preference with adjustment, but the supplier has a decision bias of ex post inventory error regret. The supply chain can perform better under the proposed approach than under only a revenue‐sharing contract. Interestingly, the proposed approach does not cause the retailer to share a higher percentage of revenue with the supplier, but it induces the supplier to replenish a higher stock quantity, which leads to higher profits for both the retailer and the supplier.
Community Healthcare Network in Underserved Areas: Design, Mathematical Models, and Analysis
Authors: Cherkesly Marilène , Rancourt Marie‐Ève , Smilowitz Karen R.
Published: February 2019

In community health programs implemented in underserved areas, community healthcare workers (CHWs) prevent, diagnose, and treat the most common diseases. To ensure continuous in‐service training of CHWs, some countries have mentored highly skilled CHWs to become supervisors. Designing a network in such a context implies determining the number of CHWs and supervisors, as well as the routing of the supervisors. This can be defined as a location‐routing covering problem (LRCP), a variant of the location‐routing and the covering tour problems. To solve the LRCP, we propose set‐partitioning formulations and a procedure to generate only non‐dominated variables without losing optimality, which also allows to break the symmetry between variables. Finding the most appropriate mathematical model is important to solve real‐life instances, improve the quality of the solution, and reduce the total computation time. Therefore, we develop tools to assist with the design and analysis of a community healthcare network in order to increase health coverage for underserved areas. Results are presented for an application in Liberia, including sensitivity analyses on various parameters and managerial insights.
Joint Decisions for Blood Collection and Platelet Inventory Control
Authors: Chen Shouchang , Li Yanzhi , Zhou Weihua
Published: February 2019

The present study investigates the benefit of joint decision making regarding whole blood collection and platelet production at a blood center. We consider a blood center that faces two types of platelet demands, differing in their freshness requirements and shortage penalty costs. We fully characterize the structure of the optimal policy regarding whole blood collection, platelet production, and inventory issuing, rationing and disposal. We find that the optimal platelet production quantity in each period is nonincreasing in the inventory levels of platelets and whole blood but that interestingly, the optimal blood collection effort may increase with the on‐hand platelet inventory level. We demonstrate with a real dataset that joint decision making leads to significant cost savings compared with separate decision making. The benefit is mainly derived from reduced blood collection and platelet production, better utilization of the collected whole blood, and reduced platelet shortage. For practical implementation, we develop a lookahead heuristic, which is shown to be very effective by numerical experiments.
Detection of ‘Candidatus Liberibacter asiaticus’ in citrus by concurrent tissue print‐based qPCR and immunoassay
Authors: Fu S. M. , Liu H. W. , Liu Q. H. , Zhou C. Y. , Hartung J. S.
Published: February 2019

‘Candidatus Liberibacter asiaticus’ (CLas) is associated with the most destructive disease of citrus, huanglongbing (HLB). The most widely used methods for detection of CLas are PCR‐based and require purification of DNA from plant samples. Elution of DNA from tissue prints made on nitrocellulose membranes followed by qPCR (TPE‐qPCR) was compared to DNA extraction of plant tissue followed by PCR (X‐PCR) by testing the same tissue samples. The former estimated a higher CLas population in tissue prints than the latter (t‐test; P = 0.009). All extracts prepared for TPE‐qPCR throughout the experiment were also tested by conventional PCR and 80.8% were identified as positive. A similar set of stem and petiole tissue samples was tested by TPE‐qPCR and immunoassay. Although the detection rate by TPE‐qPCR was higher than by immunoassay, about 6% of tissue prints were positive by immunoassay but not by TPE‐qPCR. Thus, a higher detection rate would be achieved by combining TPE‐qPCR with immunoassay. Significant differences were observed in the performance of nitrocellulose membranes from different manufacturers in these assays. Immunotissue prints showed that the spatial distribution pattern of CLas infection varied widely from one sample to another, but the patterns were highly correlated among serial sections from the same sample, suggesting that CLas preferentially colonizes adjacent phloem cells in a vertical rather than horizontal direction.
Infection risks for patients from healthcare workers with cystic fibrosis
Authors: Thomas Mark , Bagg Warwick , Kolbe John
Published: February 2019

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AbSRiM: An Agent‐Based Security Risk Management Approach for Airport Operations
Authors: Janssen Stef , Sharpanskykh Alexei , Curran Richard
Published: February 2019

Security risk management is essential for ensuring effective airport operations. This article introduces AbSRiM, a novel agent‐based modeling and simulation approach to perform security risk management for airport operations that uses formal sociotechnical models that include temporal and spatial aspects. The approach contains four main steps: scope selection, agent‐based model definition, risk assessment, and risk mitigation. The approach is based on traditional security risk management methodologies, but uses agent‐based modeling and Monte Carlo simulation at its core. Agent‐based modeling is used to model threat scenarios, and Monte Carlo simulations are then performed with this model to estimate security risks.

The use of the AbSRiM approach is demonstrated with an illustrative case study. This case study includes a threat scenario in which an adversary attacks an airport terminal with an improvised explosive device. The approach provides a promising way to include important elements, such as human aspects and spatiotemporal aspects, in the assessment of risk. More research is still needed to better identify the strengths and weaknesses of the AbSRiM approach in different case studies, but results demonstrate the feasibility of the approach and its potential.
Dental management of a child with ectrodactyly ectodermal dysplasia cleft lip/palate syndrome: A case report
Authors: Elhamouly Yasmine , Dowidar Karin ML
Published: February 2019

Ectrodactyly ectodermal dysplasia with clefting is a rare syndrome resulting from TP63 gene mutations. It is inherited in autosomal dominant manner or as a de novo transfiguration. It is characterized by a triad of ectodermal dysplasia, ectrodactyly, and facial clefts. This report represents a clinical case of 5 years and 6 months‐old male child with ectrodactyly ectodermal dysplasia cleft lip and palate syndrome requiring treatment of his carious teeth. After history taking and clinical examination, the necessary treatment was provided under general anesthesia due to the definitely negative behavior of the child. The treatment outcomes had a positive impact on the behavior and acceptance to dental treatment. This was evidenced by completion of the prosthetic and space management appliances on the dental chair. The child's quality of life was consequently improved. This was evidenced by the reduced response scores of the child perception questionnaire (CPQ11‐14) after treatment. This report highlighted the value of proper diagnosis and fulfillment of the unmet dental needs for patients with orofacial syndromes to improve their quality of life.
The seagrass skeletal assemblage from modern to fossil and from tropical to temperate: Insight from Maldivian and Mediterranean examples
Authors: Brandano Marco , Tomassetti Laura , Mateu‐Vicens Guillem , Gaglianone Giovanni
Published: February 2019

Seagrasses are marine angiosperms that form extensive submarine meadows in the photic zone where carbonate producing biota dwell as epiphytes on the leaves or as infaunal forms, and act as prolific carbonate sediment factories. Because seagrasses have a low preservation potential and records of exceptionally well‐preserved and plant material from marine settings are rare, these palaeoenvironments are difficult to identify in the rock record. Consequently, sedimentological and palaeontological proxies are the main indicators of the presence of seagrass‐dominated ecosystems. This work investigates the skeletal assemblage of Modern (Maldivian and western Mediterranean) and fossil (Eocene; Apula and Oman carbonate platforms and Oligocene; Malta platform) seagrass examples to characterize the skeletal assemblage of modern and fossil seagrasses. Two main types of grains, calcareous algae and foraminifera, constitute around 50% of the bioclastic sediment in both tropical Maldivian and temperate Mediterranean scenarios. However, in the tropical setting they are represented by green algae (Halimeda), while in the Mediterranean they are represented by corallinacean red algae. In contrast, in the Eocene examples, the foraminifera are the most conspicuous group and the green algae are also abundant. The opposite occurs in the Maltese Chattian, which is dominated by coralline algae (mean 42%), although the foraminifera are still abundant. It is suggested to use the term foralgal to identify the seagrass skeletal assemblage. To discriminate between red algae and green algae dominance, the introduction of the prefixes ‘GA’ (green algae) and ‘RA’ (red algae) is proposed. The investigated examples provide evidence that the green algae–foralgal assemblage is typical of tropical, not excessively dense seagrass meadows, characterized by a well‐illuminated substrate to support the development and calcification of the Halimeda thallus. Contrarily, the red algae‐foralgal assemblage is typical of high density tropical to subtropical seagrass meadows which create very dense oligophotic conditions on the sea floor or in temperate settings where Halimeda cannot calcify.
A large‐scale circular RNA profiling reveals universal molecular mechanisms responsive to drought stress in maize and Arabidopsis
Authors: Zhang Pei , Fan Yuan , Sun Xiaopeng , Chen Lu , Terzaghi William , Bucher Etienne , Li Lin , Dai Mingqiu
Published: February 2019

Drought is a major abiotic stress that threatens global food security. Circular RNAs (circRNAs) are endogenous RNAs. How these molecules influence plant stress responses remains elusive. Here, a large‐scale circRNA profiling identified 2174 and 1354 high‐confidence circRNAs in maize and Arabidopsis, respectively, and most were differentially expressed in response to drought. A substantial number of drought‐associated circRNA‐hosting genes were involved in conserved or species‐specific pathways in drought responses. Comparative analysis revealed that circRNA biogenesis was more complex in maize than in Arabidopsis. In most cases, maize circRNAs were negatively correlated with sRNA accumulation. In 368 maize inbred lines, the circRNA‐hosting genes were enriched for single nucleotide polymorphisms (SNPs) associated with circRNA expression and drought tolerance, implying either important roles of circRNAs in maize drought responses or their potential use as biomarkers for breeding drought‐tolerant maize. Additionally, the expression levels of circRNAs derived from drought‐responsible genes encoding calcium‐dependent protein kinase and cytokinin oxidase/dehydrogenase were significantly associated with drought tolerance of maize seedlings. Specifically, Arabidopsis plants overexpressing circGORK (Guard cell outward‐rectifying K+‐channel) were hypersensitive to abscisic acid, but insensitive to drought, suggesting a positive role of circGORK in drought tolerance. We report the transcriptomic profiling and transgenic studies of circRNAs in plant drought responses, and provide evidence highlighting the universal molecular mechanisms involved in plant drought tolerance.
AtBUD13 affects pre‐mRNA splicing and is essential for embryo development in Arabidopsis
Authors: Xiong Feng , Ren Jing‐Jing , Yu Qin , Wang Yu‐Yi , Kong Lan‐Jing , Otegui Marisa S. , Wang Xiu‐Ling
Published: February 2019

Pre‐mRNA splicing is an important step for gene expression regulation. Yeast Bud13p (bud‐site selection protein 13) regulates the budding pattern and pre‐mRNA splicing in yeast cells; however, no Bud13p homologs have been identified in plants. Here, we isolated two mutants that carry T‐DNA insertions at the At1g31870 locus and shows early embryo lethality and seed abortion. At1g31870 encodes an Arabidopsis homolog of yeast Bud13p, AtBUD13. Although AtBUD13 homologs are widely distributed in eukaryotic organisms, phylogenetic analysis revealed that their protein domain organization is more complex in multicellular species. AtBUD13 is expressed throughout plant development including embryogenesis and AtBUD13 proteins is localized in the nucleus in Arabidopsis. RNA‐seq analysis revealed that AtBUD13 mutation predominantly results in the intron retention, especially for shorter introns (≤100 bases). Within this group of genes, we identified 52 genes involved in embryogenesis, out of which 22 are involved in nucleic acid metabolism. Our results demonstrate that AtBUD13 plays critical roles in early embryo development by effecting pre‐mRNA splicing.
Canine oral primary melanoma cells exhibit shift to mesenchymal phenotype and phagocytic behaviour
Authors: Schmid Franziska , Brodesser Daniela , Reifinger Martin , Forte Sara , Semp Pia , Eberspächer‐Schweda Matthias C. , Wolschek Markus , Brandt Sabine , Kleiter Miriam , Pratscher Barbara
Published: February 2019

Canine oral malignant melanoma (COMM) is a potentially lethal cancer disease. We established primary cell lines from mostly amelanotic primary COMM and metastases and assessed lesions and derived cells for Melan A, PNL2 and CD146 expression. Then, migration and invasion of CD146‐enriched vs ‐depleted COMM cells were analysed. Epithelial‐to‐mesenchymal transition (EMT) was addressed by Vimentin‐staining and MMP2/MMP9 zymography. Phagocytic behaviour was analysed by histopathological examination and phagocytosis assay. While Melan A‐ and PNL2‐staining yielded inconsistent data, 100% of COMM sections and primary cells showed CD146 expression, suggesting that this protein may serve as a prognostic marker. An overall correlation between CD146‐expression and migration/invasion was not observed. All primary cell lines consistently expressed Vimentin and secreted biologically active MMP2, indicating that they had undergone EMT. Importantly, COMM sections exhibited cell‐in‐cell structures, and all primary cell lines exhibited phagocytic activity, supporting the concept that cell cannibalism may have a role in COMM progression.
Computed tomographic dimensions of the normal adult equine eye
Authors: Hollis Anna R. , Dixon Jonathon J. , Berlato Davide , Murray Rachel , Weller Renate
Published: February 2019

There are limited data on whether the dimensions of the equine eye and its internal structures change with bodyweight in horses. The aim of this study was to identify whether the size of the equine eye and its individual structures varied in a predictable manner with bodyweight, and to examine the reliability of computed tomography (CT) scans in the measurement of the equine eye. Ninety horses which had undergone CT examination of the head for non‐ocular disease were included. All measurements of the eye were performed twice on all eyes by the same operator to quantify intra‐operator agreement, and in 10 cases were also performed by a second operator to quantify inter‐operator agreement. Agreement was excellent for all but the rostrocaudal measurement of the anterior chamber, which was fair. The following variables correlated significantly with bodyweight: anterior‐posterior size of the globe (correlation coefficient: 0.586) and posterior segment (correlation coefficient: 0.554); the latero‐medial size of the globe (correlation coefficient: 0.452), anterior chamber (correlation coefficient: 0.504) and posterior segment (correlation coefficient: 0.455); and the orbital fossa diameter (correlation coefficient: 0.219). The lens size and anterior‐posterior distance of the anterior chamber did not correlate significantly with bodyweight. These results suggest that overall eye size and the size of the orbital fossa change with the bodyweight of the horse, but lens size remains consistent, and that CT measurements of the internal structures of the eye are repeatable and reproducible. This information aids in interventional procedures for ocular pathology and assessment of normal anatomy.
Subconjunctival bone marrow‐derived mesenchymal stem cell therapy as a novel treatment alternative for equine immune‐mediated keratitis: A case series
Authors: Davis Amanda B. , Schnabel Lauren V. , Gilger Brian C.
Published: February 2019

Equine immune‐mediated keratitis (IMMK) leads to increased corneal opacity and inflammation secondary to an alteration of the local immune system. Bone marrow‐derived mesenchymal stem cells (BM‐MSC) have been shown to modulate the immune system by downregulating inflammation. Four horses with unilateral IMMK poorly responsive to traditional medical treatments underwent novel, autologous subconjunctival BM‐MSC therapy. Bone marrow was harvested and processed as previously described for equine orthopedic disease. Horses received autologous subconjunctival BM‐MSC injections approximately every 3‐4 weeks for 1‐5 treatments total. Horses were maintained on their current medical treatment regimen throughout the BM‐MSC treatment period. Three horses had a positive response to therapy as demonstrated by an increase in corneal clarity, a decrease in neovascularization and a reduction in surface irregularity. One horse was nonresponsive to therapy. These experimental results demonstrate the safety and potential efficacy of an innovative solution for IMMK.
Use of 1% polidocanol and pre‐ and post‐computed tomography for treatment of a suspected nasolacrimal duct cyst in a dog
Authors: Zimmerman Kelli L. , Stefanacci Joseph D. , Greenberg Shari M.
Published: February 2019

Objective

To describe the efficacy of the sclerosing agent 1% polidocanol in the treatment of a suspected nasolacrimal duct cyst in a dog.

Animal Studied

A 5‐year‐old castrated male Golden Retriever with chronic epiphora of the right eye.

Procedures

Ocular examination revealed epiphora and a negative Jones test of the right eye and was otherwise normal. Computed tomography with dacryocystography confirmed a cystic structure in the right ventral orbit that extended into the caudal nasal cavity adjacent to the orbit, causing partial physical obstruction of the right nasolacrimal duct. Cytologic analysis of fluid from the lesion was supportive of a diagnosis of a cyst. One percent polidocanol (compounded, People's Custom Rx, Memphis, TN) was injected into the cyst.

Results

Epiphora was resolved by two weeks post‐injection. Repeated computed tomography with dacryocystography was performed 8 months post‐injection, revealing complete resolution of the cyst and demonstrating mild enophthalmos of the right globe.

Conclusions

Intralesional 1% polidocanol therapy was successful in resolving a suspected nasolacrimal duct cyst in a dog.
Ocular dermoids in dogs: A retrospective study
Authors: Badanes Zachary , Ledbetter Eric C.
Published: February 2019

Objective

To describe clinical features of dogs diagnosed with ocular dermoids at two veterinary teaching hospitals.

Animals studied

Retrospective case series of 44 dogs (49 dermoids) with ocular dermoids.

Procedures

Medical records of dogs evaluated by the Cornell University and University of Pennsylvania ophthalmology services were evaluated to identify dogs with a clinical diagnosis of ocular dermoids between 2004 and 2018, and 2011 and 2018, respectively. Signalment, historical, and clinical details were recorded, including dermoid location, concurrent diseases, treatment, histopathologic findings, and outcome.

Results

A total of 49 ocular dermoids, involving 47 eyes, were diagnosed in 44 dogs. The mean ( standard deviation) age of the study population at the time of diagnosis was 1.19 years (1.85 years). Of the 44 dogs evaluated, 28 (63.6%) were male and 30 (68.2%) were intact at time of diagnosis. Twenty‐two different breeds were represented in the study, with mixed breed, French Bulldog, and Shih Tzu being the most common. Twenty‐two dermoids were categorized as limbal (44.9%), 14 as eyelid (28.6%), eight as corneal (16.3%), and five as conjunctival (10.2%). Concurrent ocular findings were noted in 29 of the 47 eyes (61.7%), including corneal pigmentation, epiphora, and conjunctival hyperemia. Nine dogs (20.5%) suffered from concurrent systemic disease, with the majority being cardiac in origin. A total of 34 dermoids (69.4%) were surgically excised with no recurrences.

Conclusions

Ocular dermoids are an uncommon condition in dogs. Concurrent congenital cardiac disease was relatively common in the dogs of this study. Surgical excision of dermoids was curative.
Physiological properties of the lamina I spinoparabrachial neurons in the mouse
Authors: Allard Julien
Published: February 2019

Key points

Spinal cord lamina I neurons receiving dense input from nociceptors and projecting to the parabrachial area at the ponto‐mesencephalic junction form the major ascending pain‐related pathway in rodents.

Lamina I spinoparabrachial (SPB) neurons have never been characterized in mice, despite the growing and extensive use of this species to understand the contribution of lamina I SPB neurons in chronic pain.

The electrophysiological properties of lamina I SPB neurons recorded here in anaesthetized mice are comparable to those of rat or cat, forming a nociceptive and thermoreceptive pathway. It was confirmed ‘on line’ that lamina I SPB neurons that normally encode noxious stimuli can receive input from low threshold mechanoreceptors in certain conditions. The present work indicates that the study of lamina I SPB neurons in vivo could take advantage of the use of genetically modified mice.

Ongoing studies investigating the role of lamina I projection neurons in the generation of chronic pain are mainly based on the use of genetically modified mice. However, lamina I projection neurons have never been physiologically characterized in this species. The present work aimed to fill this gap, and to assess the effect of spinal ‘disinhibition’ that may occur in chronic pain states on the responses of these neurons to light touch. Seventy lamina I spinoparabrachial (SPB) neurons were characterized in anaesthetized mice. These neurons showed low central conduction velocities (<12.4 m s−1) and wide range of responses. Fifty‐six neurons responded equally to noxious mechanical and thermal (heat) stimuli (16% responded consistently to light touch). Modality‐specific neurons responded preferentially to thermal (cold) stimuli (n = 10) and pinch (n = 2), or specifically to heat (n = 2). Spinal bicuculline and strychnine application induced responses to brush in half of the neurons tested, confirming directly the potential connection between low threshold mechanoreceptors and nociceptive‐specific neurons, responsible for mechanical allodynia. Remarkably, the effect of the treatment was highly variable and apparently independent of the initial profile of the neurons. The present data confirm that mice lamina I SPB neurons have the expected characteristics to form a nociceptive and thermoreceptive pathway, but they constitute a highly heterogeneous group. The differential effect of spinal disinhibition observed here suggests that a subgroup of lamina I SPB neurons might be responsible for abnormal pain in pathological conditions, and emphasizes the importance of in vivo recording, a neglected approach.
Numerical Investigations of Flow and Heat Transfer Characteristics Between Turbulent Double Jet Impingement and a Moving Plate
Authors: Satish N. , Venkatasubbaiah K.
Published: February 2019

The analysis of fluid flow and heat transfer characteristics of double turbulent jet flow impinging on a stationary and moving plate has been numerically studied. Unsteady-state two-dimensional incompressible turbulent forced convection flow is considered for present analysis. Turbulence is modelled by the Reynolds-averaged Navier–Stokes (RANS) equation with the k − ε model and enhanced wall treatment. The governing equations are solved using a finite volume based commercial solver. The results for the effect of single jet and double jet, jet Reynolds number, plate velocity, location, and center spacing between the two jets on flow and heat transfer characteristics are reported. The results show that the enhancement of heat transfer is 32.70% for the double jet compared with the single jet impingement on a stationary plate. As significant enhancement of heat transfer is observed with an increase in the second jet Reynolds number and plate velocity. The results show that the size and shape of the recirculation zones between jets are greatly altered with respect to spacing between the jets to the plate and the center distance between the jets. The results show that the enhancement of heat transfer is 37.3% for moving plate velocity due to a decrease in the spacing between the jets and the plate from 6 to 4. Results show that the local peak Nusselt number is influenced by the plate velocity. These results are validated by experimental and numerical results available in the literature.
Modeling Strategy for the Analysis of Forced Draft Air-Cooled Condensers Using Rotational Fan Models
Authors: Engelbrecht Ruan A. , Meyer Chris J. , van der Spuy Johan
Published: February 2019

Air-cooled condenser (ACC) design methodologies use empirical correlations that are unable to account for the complex flow phenomena associated with ACCs. Numerical models are seen as an alternative evaluation tool. This paper details the development of a modeling strategy for an ACC in the computational fluid dynamics (CFD) code of OpenFOAM. The axial flow fan is modeled using the extended actuator disk model (EADM) and validated using the B2a-fan. A good agreement between experimental and numerical results are noted for the volumetric flow rates expected in the ACC operating range. The A-frame heat exchanger is also validated using the empirical data. The ACC operating point is numerically and analytically determined. An overprediction of the numerical results to the analytical solution is attributed to the presence of kinetic energy recovery and validated using experimental results. A numerical recovery coefficient of 0.527 is measured and correlates well with the experimentally determined coefficient of 0.553.
Optimum Design of Serial Robots
Authors: Gupta Vinay , Saha Subir Kumar , Chaudhary Himanshu
Published: February 2019

An optimum design of an industrial robot can be achieved from different point of views. For example, a robot can be conceived from the standpoint achieving maximum workspace or minimum weight, etc. In this paper, the objective is to arrive at a robot design that will require optimum driving torques/forces at its joints to perform tasks within its workspace. Such a design will automatically save energy. Note that these torques/forces at the joints are highly dependent on the mass and the inertia properties of the robot’s links. Therefore, these quantities were minimized by determining the optimum masses and optimum mass centers and finding out the corresponding inertia properties of the moving links. Such an approach was briefly introduced earlier by the authors with the help of a simple two-link planar arm. In this paper, the concept is generalized and demonstrated with the help of a complex robot, a 6-degrees-of-freedom PUMA robot. To achieve the design for optimum driving torques/forces at the joints, the concept of equimomental system of point masses was introduced, which helped to obtain the optimum locations of the mass centers of each link quite conveniently. However, to compute the driving torques/forces recursively for such equivalent point mass systems, the decoupled natural orthogonal complement matrices for point masses (DeNOC-P) was derived. It has led to a simplified algorithm for obtaining driving torques/forces. The proposed algorithm for optimization is illustrated with the help of a PUMA robot.
Assessment of Topography Parameters During Running-In and Subsequent Rolling Contact Fatigue Tests
Authors: Prajapati Deepak K. , Tiwari Mayank
Published: February 2019

Rolling contact fatigue (RCF) is one of the major problems observed in gear mechanisms, which leads to high friction, ultimately resulting in high energy consumption. This paper demonstrates the evolution of surface topography during running-in and subsequent RCF tests under boundary or mixed-elastohydrodynamic lubrication regimes. The case-hardened disks of equal surface finish and hardness are used in the experiments, and the evolution of surface topography is investigated using a white light interferometer. Surface topography at different load stages is measured at three distinct points, on the disks and average roughness and topography parameters are reported. Semi-quantitative techniques are used to determine the asperity-level parameters at different load stages. From the running-in experiment, it is found that running-in is a fast process where substantial change in surface topography occurs due to plastic deformation of most prominent asperity. From the RCF test, it is concluded that within range of the fatigue cycles, the root-mean-square (RMS) roughness (Sq) is negatively correlated with the summit radius (R) and the autocorrelation length (Sal) and positively correlated with the summit density (Sds) and the RMS slope (Sdq). Scanning electron microscope (SEM) analysis reveals the disappearance of grinding ridges, the formation of micropits at a very small scale, and pit growth in the sliding direction.
Facile Synthesis of Uniform Calcite Microcubes and Their Enhanced Tribological Performance in Lithium-Based Commercial Grease
Authors: Akhtar Khalida , Hussain Abid , Gul Muhammad , Khalid Hina , Yousaf Zai Saniya
Published: February 2019

This study describes a facile synthesis of calcium carbonate (CaCO3) monodispersed fine particles from an abundant indigenous and economical source (quicklime) and its enhanced tribological performance as a green additive in commercial lithium grease (CLG). The effects of various experimental parameters on particle morphology were thoroughly examined, and the conditions were optimized. The synthesized uniform particles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and thermogravimetric (TG) /differential thermal analysis (DTA), and their results confirmed the calcite structure of the synthesized particles. The friction and wear studies were carried out under the applied load of 0.863 N at an ambient temperature for 5 min. The tribological performance of various amounts (1–7%) of cubic-CaCO3 (CCC) particles in CLG showed that 5 wt. % of CCC was the optimum concentration as additive in the present case. For comparison purposes, a commercial CaCO3 powder was used and a decrease in the friction coefficient of CLG was observed to be 33.4% and 16.4% for 5 wt. % CCC and commercial CaCO3 additives, respectively. The significantly enhanced antiwear and antifriction performance of the optimum CCC-CLG in comparison with the blank and commercial CaCO3-additized CLG was quite encouraging, and extensive studies in a real machine-operating environment are in progress for evaluation of the CCC-CLG blend to be used as an economical, green, and high-performance lubricant in mechanical components.
Stability Analysis of Highly Deviated Boreholes to Minimize Drilling Risks and Nonproductive Time
Authors: Abbas Ahmed K. , Flori Ralph E. , Alsaba Mortadha
Published: February 2019

The Lower Cretaceous Zubair Formation is a regionally extended gas- and oil-producing sandstone sequence in Southern Iraq. Due to the weak nature of the Zubair Formation, the lack of wellbore stability is one of the most critical challenges that continuously appears during the drilling development operations. Problems associated with lack of wellbore stability, such as the tight hole, shale caving, stuck pipe, and sidetracking, are both time-consuming and expensive. This study aimed to construct a geotechnical model based on offset well data, including rock mechanical properties, in situ stresses, and formation pore pressure, coupled with suitable rock failure criteria. Mohr–Coulomb and Mogi–Coulomb failure criteria were used to predict the potential rock failure around the wellbore. The effect of the inclination and azimuth of the deviated wells on the shear failure and tensile failure mud weights was investigated to optimize the wellbore trajectory. The results show that the best orientation to drill highly deviated wells (i.e., inclinations higher than 60 deg) is along to the minimum horizontal stress (140 deg). The recommended mud weight for this selected well trajectory ranges from 1.45 to 1.5 g/cc. This study emphasizes that a wellbore stability analysis can be applied as a cost-effective tool to guide future highly deviated boreholes for better drilling performance by reducing the nonproductive time.
Fuzzy Sliding Mode Controller Design for a Cooperative Robotic System With Uncertainty for Handling an Object
Authors: Farahmandrad Maryam , Ganjefar Soheil , Talebi Heidar Ali , Bayati Mahdi
Published: February 2019

This paper proposes a control framework for a cooperative robotic system to grasp and handle an object with known geometry in the presence of uncertainty in robot dynamics. Based on passive decomposition approach, dynamic equations of the cooperative robotic system are decomposed into two decoupled systems, shape and locked systems. The locked system and the shape system are controlled by two fuzzy sliding mode controllers (SMCs). Stability is studied through passivity property and Lyapunov theorem. Simulation results confirm that the proposed control scheme works well.
Fixed-Time Inverse Dynamics Control for Robot Manipulators
Authors: Su Yuxin , Zheng Chunhong
Published: February 2019

This paper concerns with global fixed-time trajectory tracking of robot manipulators. A simple nonlinear inverse dynamics control (IDC) is proposed by using bi-limit homogeneity technique. Lyapunov stability theory and geometric bi-limit homogeneity technique are employed to prove global fixed-time tracking stability. It is proved that there exists a convergence time that is uniformly bounded a priori and such a bound is independent of the initial states such that the tracking errors converge to zero globally. The appealing advantages of the proposed control are that it is fairly easy to construct and has the global fixed-time tracking stability featuring faster transient and higher steady-state precision. Numerical simulation comparisons are provided to demonstrate the improved performance of the proposed approach.
Coherence resonance and stochastic bifurcation behaviors of simplified standing-wave thermoacoustic systems
Authors: Li Xinyan , Zhao Dan , Shi Baolu
Published: February 2019

In this work, noise-induced motions (i.e., external fluctuations) in two modelled standing-wave thermoacoustic systems are studied when these systems are close to the deterministic stability boundary. These systems include (1) open-open (i.e., Rijke-type) and (2) closed-open boundary conditions. It is found from the smooth transitions of the stationary probability density function that the thermoacoustic system is destabilized via stochastic P bifurcation, as the external noise intensity is continuously increased. In addition, the increased noise intensity can shift the hysteresis region, which makes the system more prone to quasi-periodic oscillations, but also reduces the hysteresis area. The noise-induced coherence motions are observed numerically in the open-open system, which is denoted by the occurrence of a bell-shaped signal to noise ratio (SNR). The SNR is shown to be applicable as a precursor. It becomes larger and the optimal noise intensity is decreased as the modelled thermoacoustic system approaches the critical bifurcation point. In addition, coherence resonance is observed in the closed-open system. To validate the findings, experimental studies are conducted on an open-open Rijke tube. Good qualitative agreements are obtained. The present study shed lights on the stochastic and coherence behaviors of the standing-wave thermoacoustic systems with different boundary conditions.
In Vitro
Activity of Tebipenem (SPR859) against Penicillin-Binding Proteins of Gram-Negative and Gram-Positive Bacteria
Authors: Lacasse Evelyne , Brouillette Eric , Larose Audrey , Parr Thomas R. , Rubio Aileen , Malouin François
Published: February 2019

Tebipenem (SPR859) is the microbiologically active form of SPR994 (tebipenem-pivoxil), an orally available carbapenem with activity against extended-spectrum β-lactamase (ESBL)-producing
Enterobacteriaceae
. Measurement of the relative binding of SPR859 to the bacterial cell targets revealed that it is a potent inhibitor of multiple penicillin-binding proteins (PBPs) but primarily a Gram-negative PBP 2 inhibitor, similar to other compounds in this class.
Viability Screen of LOPAC
1280
Reveals Tyrosine Kinase Inhibitor Tyrphostin A9 as a Novel Partner Drug for Artesunate Combinations To Target the
Plasmodium falciparum
Ring Stage
Authors: Tong Jie Xin , Ang Sarah E. L. , Tan Esther H. N. , Tan Kevin S. W.
Published: February 2019

The emergence of artemisinin-resistant
Plasmodium falciparum
poses a major threat to current frontline artemisinin combination therapies. Artemisinin resistance is widely associated with mutations in the
P. falciparum
Kelch13 (PfKelch13) propeller region, leading to delayed parasite clearance and increased survival of early-ring-stage parasites.
Human Papillomavirus E6/E7 and Long Noncoding RNA TMPOP2 Mutually Upregulated Gene Expression in Cervical Cancer Cells
Authors: He Hongpeng , Liu Xiang , Liu Yue , Zhang Mengmeng , Lai Yongwei , Hao Yunpeng , Wang Qiutong , Shi Danyang , Wang Nan , Luo Xue-Gang , Ma Wenjian , Zhang Tong-Cun
Published: February 2019

Human papillomaviruses 16 and 18 (HPV16/18) are the main causative agents of cervical cancer. Viral proteins HPV16/18 E6 and E7 are constitutively expressed in cancer cells to maintain oncogenic phenotypes. Accumulating evidences suggest that HPVs are correlated with the deregulation of long noncoding RNAs (lncRNAs) in cervical cancer, although the mechanism was unexplored in most cases. TMPOP2 is a newly identified lncRNA excessively expressed in cervical cancer. However, the mechanism for the upregulation of
TMPOP2
in cervical cancer cells remains largely unknown and its relationship with HPVs is still elusive. The significance of our research is in revealing the mutual upregulation of HPV16/18 E6/E7 and TMPOP2 with the molecular mechanisms explored. This study will expand our understandings of the oncogenic activities of human papillomaviruses and lncRNAs.
Punctuated Evolution of Myxoma Virus: Rapid and Disjunct Evolution of a Recent Viral Lineage in Australia
Authors: Kerr Peter J. , Eden John-Sebastian , Di Giallonardo Francesca , Peacock David , Liu June , Strive Tanja , Read Andrew F. , Holmes Edward C.
Published: February 2019

The coevolution of myxoma virus (MYXV) and European rabbits in Australia is one of the most important natural experiments in evolutionary biology, providing insights into virus adaptation to new hosts and the evolution of virulence. Previous studies of MYXV evolution have also shown that the virus evolves both relatively rapidly and in a strongly clock-like manner. Using newly acquired MYXV genome sequences from Australia, we show that the virus has experienced a dramatic change in evolutionary behavior over the last 20 years, with a breakdown in clock-like structure, the appearance of a rapidly evolving virus lineage, and the accumulation of multiple nonsynonymous and indel mutations. We suggest that this punctuated evolutionary event may reflect a change in selection pressures as rabbit numbers declined following the introduction of rabbit hemorrhagic disease virus and drought in the geographic regions inhabited by rabbits.
Coronavirus Endoribonuclease Activity in Porcine Epidemic Diarrhea Virus Suppresses Type I and Type III Interferon Responses
Authors: Deng Xufang , van Geelen Albert , Buckley Alexandra C. , O’Brien Amornrat , Pillatzki Angela , Lager Kelly M. , Faaberg Kay S. , Baker Susan C.
Published: February 2019

Coronaviruses (CoVs) can emerge from an animal reservoir into a naive host species to cause pandemic respiratory or gastrointestinal diseases with significant mortality in humans or domestic animals. Porcine epidemic diarrhea virus (PEDV), an alphacoronavirus (alpha-CoV), infects gut epithelial cells and macrophages, inducing diarrhea and resulting in high mortality in piglets. How PEDV suppresses the innate immune response was unknown. We found that mutating a viral endoribonuclease, EndoU, results in a virus that activates both the type I interferon response and the type III interferon response in macrophages and epithelial cells. This activation of interferon resulted in limited viral replication in epithelial cell cultures and was associated with reduced virus shedding and mortality in piglets. This study reveals a role for EndoU activity as a virulence factor in PEDV infection and provides an approach for generating live-attenuated vaccine candidates for emerging coronaviruses.
Mycobacterium ulcerans Population Genomics To Inform on the Spread of Buruli Ulcer across Central Africa
Authors: Vandelannoote Koen , Phanzu Delphin Mavinga , Kibadi Kapay , Eddyani Miriam , Meehan Conor J. , Jordaens Kurt , Leirs Herwig , Portaels Françoise , Stinear Timothy P. , Harris Simon R. , de Jong Bouke C.
Published: February 2019

Buruli ulcer is a destructive skin and soft tissue infection caused by
Mycobacterium ulcerans
. The disease is characterized by progressive skin ulceration, which can lead to permanent disfigurement and long-term disability. Currently, the major hurdles facing disease control are incomplete understandings of both the mode of transmission and environmental reservoirs of
M. ulcerans
. As decades of spasmodic environmental sampling surveys have not brought us much closer to overcoming these hurdles, the Buruli ulcer research community has recently switched to using comparative genomics. The significance of our research is in how we used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our approach shows that it might be possible to use bacterial population genomics to assess the impact of health interventions, providing valuable feedback for managers of disease control programs in areas where health surveillance infrastructure is poor.