bluuebunny/crossref_metadata_2025 huggingface dataset:
Reproductive isolation between Salvia elegans and S. fulgens, two hummingbird‐pollinated sympatric sages
Authors: Cuevas E. , Espino J. , Marques I.
Published: July 2018

The integrity of species in sympatric contact sites is dependent on the existence of reproductive isolating mechanisms, which restrict gene flow between them. However, we know little about the mechanisms that enable the coexistence of species with similar floral morphologies. Here, we evaluated several reproductive isolation barriers between Salvia elegans and S. fulgens, two sympatric sages with a similar ornithophilous floral syndrome, offering nectar as the main reward.

Over 3 years, we evaluated broad‐scale geographic isolation, floral phenologies and floral visitors as pre‐pollination barriers, and fruit set, seed number and seed germination as post‐pollination barriers.

We found considerable geographic isolation and significant altitudinal differences between the two sages. The flowering period of both sages always overlapped extensively during the 3 years of this study, but hummingbirds were highly specific, visiting one or the other Salvia species and showing aggressive territorial behaviour. Interspecific experimental crosses revealed that hybrid seeds might be formed although strong asymmetric barriers were found depending on the species acting as the maternal donor.

Despite the low level of flowering asynchrony, reproductive isolation was remarkably high in the two sages. Geographic isolation and pollinator fidelity were the main factors responsible for maintaining species integrity. Despite an extensive review, we found very few studies quantifying the efficiency of isolation barriers in Neotropical plants or even the importance of hummingbirds as pollinators.
Whole‐plant reddening in Silene germana is due to anthocyanin accumulation in response to visible light
Authors: Narbona E. , Jaca J. , del Valle J. C. , Valladares F. , Buide M. L.
Published: July 2018

The phenology of anthocyanin accumulation in leaves has been widely studied in perennial plants; several hypotheses have been proposed to explain their adaptive significance. Here, we explored the photoprotection hypothesis in Silene germana, a Mediterranean annual plant with late‐spring/summer flowering.

We analysed the temporal patterns of anthocyanin accumulation in photosynthetic calyces, leaves and stems and throughout the reproductive season, and their relationship with flower abortion, florivory and plant mortality due to drought. In addition, the flavonoid production and the photoinhibitory response were measured in a shading experiment.

The whole plant becomes red at the end of the flowering and remains red until fruiting and senescence. Calyces were redder on the side with more sun exposition. Aborted flowers showed redder calyces than those of fruiting flowers. No effect of plant redness on florivory or plant mortality was found. The shading experiment showed a positive relationship between anthocyanin accumulation and intensity of solar radiation, but plants growing in absence of UV showed similar redness than full sunlight plants. Plants growing in natural shade lack anthocyanins but produced the same amount of non‐anthocyanin flavonoids. Anthocyanic and non‐anthocyanic plants showed similar photochemical efficiency (Fv/Fm) after sun exposition, but in early morning, the former showed lower Fv/Fm values. Plants growing in full sunlight produced more fruits than those of natural shade plants.

Whole‐plant reddening during fruiting and senescence appears to be a property of S. germana. Our results suggest that anthocyanin accumulation depends on sunlight intensity, but non‐anthocyanin flavonoids are produced constitutively.
Towards an assessment of perceived COPD exacerbation triggers: Initial development and validation of a questionnaire
Authors: Werchan Chelsey A. , Steele Ashton M. , Janssens Thomas , Millard Mark W. , Ritz Thomas
Published: July 2018

Background and objective

Prevention of exacerbations in chronic obstructive pulmonary disease (COPD) is important to decrease overall declines in functioning and improve quality of life. The present study sought to develop a psychometrically valid measure of perceived triggers of exacerbations in COPD patients, the COPD Exacerbation Trigger Inventory (CETI).

Methods

Participants (n = 192) were recruited through local clinics and online to complete surveys of the CETI, demographic information, disease‐specific information and the COPD Assessment Test (CAT). The CETI included a free response section on patients’ individual top triggers, combined with ratings of their controllability.

Results

Exploratory principal component analyses identified a stable 5‐factor structure (33 items), from which trigger subscales for weather/climate, air pollution/irritants, exercise, infection/illness and psychological factors were formed (internal consistency Cronbach's α = 0.90–0.94). Trigger factors were associated with COPD functional status, exacerbation frequency and healthcare utilization. Participants found personal triggers related to dust, air pollution, smoking and physical activity to be the most easily controlled, whereas those related to psychological factors, climate, infection, respiratory symptoms and sleep to be more difficult to control. Greater perceived controllability of triggers was associated with lower CAT scores, indicating better health status and less impact of the disease on functioning.

Conclusion

The CETI is a psychometrically valid measure of perceived exacerbation triggers in patients with COPD. Perceived triggers are associated with clinical outcomes. Assessment of trigger classes and their controllability may prove useful in both research and clinical settings with COPD patients and to further our knowledge in prevention and disease management.
Identification of a novel HLA‐DQB1 allele, DQB1*06:111, by sequence‐based typing in a Taiwanese individual
Authors: Chang C. L. , Lin C. Y.
Published: July 2018

HLA‐DQB1*06:111 differs from HLA‐DQB1*06:02:01 by the single nucleotide substitution resulting in one amino acid change.
Natural variation in GmGBP1 promoter affects photoperiod control of flowering time and maturity in soybean
Authors: Zhao Lin , Li Minmin , Xu Chongjing , Yang Xue , Li Dongmei , Zhao Xue , Wang Kuo , Li Yinghua , Zhang Xiaoming , Liu Lixue , Ding Fuquan , Du Hailong , Wang Chunsheng , Sun Jingzhe , Li Wenbin
Published: July 2018

The present study screened for polymorphisms in coding and non‐coding regions of the GmGBP1 gene in 278 soybean accessions with variable maturity and growth habit characteristics under natural field conditions in three different latitudes in China. The results showed that the promoter region was highly diversified compared with the coding sequence of GmGBP1. Five polymorphisms and four haplotypes were closely related to soybean flowering time and maturity through association and linkage disequilibrium analyses. Varieties with the polymorphisms SNP_‐796G, SNP_‐770G, SNP_‐307T, InDel_‐242normal, SNP_353A, or haplotypes Hap‐3 and Hap‐4 showed earlier flowering time and maturity in different environments. The shorter growth period might be largely due to higher GmGBP1 expression levels in soybean that were caused by the TCT‐motif with SNP_‐796G in the promoter. In contrast, the lower expression level of GmGBP1 in soybean caused by RNAi interference of GmGBP1 resulted in a longer growth period under different day lengths. Furthermore, the gene interference of GmGBP1 also caused a reduction in photoperiod response sensitivity (PRS) before flowering in soybean. RNA‐seq analysis on GmGBP1 underexpression in soybean showed that 94 and 30 predicted genes were significantly upregulated and downregulated, respectively. Of these, the diurnal photoperiod‐specific expression pattern of three significant flowering time genes GmFT2a, GmFT5a, and GmFULc also showed constantly lower mRNA levels in GmGBP1‐i soybean than in wild type, especially under short day conditions. Together, the results showed that GmGBP1 functioned as a positive regulator upstream of GmFT2a and GmFT5a to activate the expression of GmFULc to promote flowering on short days.
The multistress‐induced Translocator protein (TSPO) differentially modulates storage lipids metabolism in seeds and seedlings
Authors: Jurkiewicz Pawel , Melser Su , Maucourt Mickaël , Ayeb Haitham , Veljanovski Vasko , Maneta‐Peyret Lilly , Hooks Mark , Rolin Dominique , Moreau Patrick , Batoko Henri
Published: July 2018

Translocator proteins (TSPO) are conserved membrane proteins extensively studied in mammals, but their function is still unclear. Angiosperm TSPO are transiently induced by abiotic stresses in vegetative tissues. We showed previously that constitutive expression of the Arabidopsis TSPO (AtTSPO) could be detrimental to the cell. Degradation of AtTSPO requires an active autophagy pathway. We show here that genetic modifications of TSPO expression in plant and yeast cells reduce the levels of cytoplasmic lipid droplets (LD). Transgenic Arabidopsis seedlings overexpressing AtTSPO contain less LD as compared with wild type (WT). LD levels were increased in Arabidopsis AtTSPO knockout (KO) seedlings. Deletion of the Schizosaccharomyces pombe TSPO resulted in an increase in LD level in the cell. As compared with the WT, the mutant strain was more sensitive to cerulenin, an inhibitor of fatty acids and sterol biosynthesis. We found that in contrast with seedlings, overexpression of AtTSPO (OE) resulted in an up to 50% increase in seeds fatty acids as compared with WT. A time course experiment revealed that after 4 days of seed imbibition, the levels of triacylglycerol (TAG) was still higher in the OE seeds as compared with WT or KO seeds. However, the de novo synthesis of phospholipids and TAG after 24 h of imbibition was substantially reduced in OE seeds as compared with WT or KO seeds. Our findings support a plant TSPO role in energy homeostasis in a tissue‐specific manner, enhancing fatty acids and LD accumulation in mature seeds and limiting LD levels in seedlings.
Diacylglycerol acyltransferase 1 is activated by phosphatidate and inhibited by SnRK1‐catalyzed phosphorylation
Authors: Caldo Kristian Mark P. , Shen Wei , Xu Yang , Hanley‐Bowdoin Linda , Chen Guanqun , Weselake Randall J. , Lemieux M. Joanne
Published: July 2018

Diacylglycerol acyltransferase 1 (DGAT1) catalyzes the final and committed step in the Kennedy pathway for triacylglycerol (TAG) biosynthesis and, as such, elucidating its mode of regulation is critical to understand the fundamental aspects of carbon metabolism in oleaginous crops. In this study, purified Brassica napus diacylglycerol acyltransferase 1 (BnaDGAT1) in n‐dodecyl‐β‐d‐maltopyranoside micelles was lipidated to form mixed micelles and subjected to detailed biochemical analysis. The degree of mixed micelle fluidity appeared to influence acyltransferase activity. BnaDGAT1 exhibited a sigmoidal response and eventual substrate inhibition with respect to increasing concentrations of oleoyl‐CoA. Phosphatidate (PA) was identified as a feed‐forward activator of BnaDGAT1, enabling the final enzyme in the Kennedy pathway to adjust to the incoming flow of carbon leading to TAG. In the presence of PA, the oleoyl‐CoA saturation plot became more hyperbolic and desensitized to substrate inhibition indicating that PA facilitates the transition of the enzyme into the more active state. PA may also relieve possible autoinhibition of BnaDGAT1 brought about by the N‐terminal regulatory domain, which was shown to interact with PA. Indeed, PA is a key effector modulating lipid homeostasis, in addition to its well recognized role in lipid signaling. BnaDGAT1 was also shown to be a substrate of the sucrose non‐fermenting‐1‐related kinase 1 (SnRK1), which catalyzed phosphorylation of the enzyme and converted it to a less active form. Thus, this known regulator of carbon metabolism directly influences TAG biosynthesis.
Comparative efficacy of three antiseptics as surgical skin preparations in dogs
Authors: Boucher Charles , Henton Maryke M. , Becker Piet J. , Kirberger Robert M. , Hartman Marthinus J.
Published: July 2018

Objective

To compare the antimicrobial efficacy of a 2% chlorhexidine gluconate and 70% ethanol solution (CG+A) with that of F10 Skin Prep Solution (F10) and electrochemically activated water (EAW) when used as a surgical preparation in canine patients.

Study design

Prospective randomized clinical study.

Sample population

One hundred sixteen dogs presented for ovariohysterectomy.

Methods

Dogs were randomly divided into 1 of the 3 antiseptic groups (CG+A, F10, EAW). Skin samples with replicating organism detection and counting plates were taken at 4 different perioperative sites and time intervals (postskin preparation, postskin antisepsis, 2 hours after the second sample, and at the end of surgery) during ovariohysterectomies performed by students. The colony forming unit (CFU) counts from each sample were quantified according to the level of bacterial contamination. Zero CFU was defined as no contamination, 1‐12 CFU was defined as low contamination, and greater than 12 CFU was defined as high contamination. The 3 antiseptics were compared with respect to the level of contamination.

Results

There was no difference in the level of colonization between the antiseptics at the first sampling time (P = .454). However, the level of contamination for CG+A was lower compared with F10 and EAW at the second, third, and fourth sampling times (P = .001,P = .01,P = .02, respectively).

Conclusion

CG+A was more effective at achieving a zero CFU count and low levels of contamination compared with F10 and EAW for surgical preparation in dogs undergoing ovariohysterectomy.

Clinical significance

This study does not provide evidence to support the use of F10 and EAW instead of CG+A for the surgical skin preparation of dogs undergoing ovariohysterectomy.
Arthroscopic approach and intra‐articular anatomy of the equine atlanto‐occipital joint
Authors: Wright Linda , Puchalski Sarah M. , Kristoffersen Mads , Lindegaard Casper
Published: July 2018

Objective

To develop arthroscopic approaches to the atlanto‐occipital (A‐O) and describe associated arthroscopic anatomy.

Study design

Experimental ex vivo study and clinical case report.

Animals

Ten equine cadaver joints and 1 clinical case.

Methods

CT arthrograms of 8 A‐O joints were performed to determine the placement of an arthroscopic portal. Arthroscopy was performed via dorsal and/or ventral approaches (dorsal or ventral to the longissimus capitis tendon) in 10 cadaveric A‐O joints and the A‐O joint of a 2‐week‐old foal with septic arthritis. Accessible cartilage was debrided in 3 cadaver joints. Accessibility and risks were assessed by review of arthroscopic images, postoperative necropsy, and computed tomography (CT).

Results

Dorsal and ventral outpouchings of the A‐O joint were identified with CT. Arthroscopy of the dorsal pouch provided access to 50% of the dorsocranial occipital condyle and 15% of the dorsocranial atlas articular surfaces. Joint distension caused displacement of the dura. Dura perforation occurred with a blind dorsal approach in 2 of 5 joints. Dura perforation did not occur after ultrasonography‐guided approaches. Arthroscopic debridement of septic arthritis and osteomyelitis was successful in 1 clinical case.

Conclusion

Approaches to the A‐O joint were determined from CT examinations. The cranial aspect of the dorsal pouch of the A‐O joint was accessed via arthroscopic triangulation in all horses of this study. Ultrasound‐guided joint access prevented perforation of vital structures, including the spinal canal.

Clinical significance

Advanced imaging improves the diagnosis of A‐O joint pathology. Descriptions of arthroscopic anatomy and accessibility provide important information for surgical intervention.
Central sensitization of the spino‐parabrachial‐amygdala pathway that outlasts a brief nociceptive stimulus
Authors: Kissiwaa Sarah A , Bagley Elena E
Published: July 2018

Key points

Chronic pain is disabling because sufferers form negative associations between pain and activities, such as work, leading to the sufferer limiting these activities. Pain information arriving in the amygdala is responsible for forming these associations and contributes to us feeling bad when we are in pain.

Ongoing injuries enhance the delivery of pain information to the amygdala. If we want to understand why chronic pain can continue without ongoing injury, it is important to know whether this facilitation continues once the injury has healed.

In the present study, we show that a 2 min noxious heat stimulus, without ongoing injury, is able to enhance delivery of pain information to the amygdala for 3 days. If the noxious heat stimulus is repeated, this enhancement persists even longer.

These changes may prime this information pathway so that subsequent injuries may feel even worse and the associative learning that results in pain‐related avoidance may be promoted.

Pain is an important defence against dangers in our environment; however, some clinical conditions produce pain that outlasts this useful role and persists even after the injury has healed. The experience of pain consists of somatosensory elements of intensity and location, negative emotional/aversive feelings and subsequent restrictions on lifestyle as a result of a learned association between certain activities and pain. The amygdala contributes negative emotional value to nociceptive sensory information and forms the association between an aversive response and the environment in which it occurs. It is able to form this association because it receives nociceptive information via the spino‐parabrachio‐amygdaloid pathway and polymodal sensory information via cortical and thalamic inputs. Synaptic plasticity occurs at the parabrachial‐amygdala synapse and other brain regions in chronic pain conditions with ongoing injury; however, very little is known about how plasticity occurs in conditions with no ongoing injury. Using immunohistochemistry, electrophysiology and behavioural assays, we show that a brief nociceptive stimulus with no ongoing injury is able to produce long‐lasting synaptic plasticity at the rat parabrachial‐amygdala synapse. We show that this plasticity is caused by an increase in postsynaptic AMPA receptors with a transient change in the AMPA receptor subunit, similar to long‐term potentiation. Furthermore, this synaptic potentiation primes the synapse so that a subsequent noxious stimulus causes prolonged potentiation of the nociceptive information flow into the amygdala. As a result, a second injury could have an increased negative emotional value and promote associative learning that results in pain‐related avoidance.
Influence of Internal Corrosive Defect on the Burn-Through of In-Service Welding on Pipelines
Authors: Qian Wu , Yong Wang , Tao Han , Ling Ding
Published: July 2018

In the course of the service of long-distance oil/gas pipelines, due to corrosion, abrasion, and other reasons, the possibility of pipeline leakage is growing. In-service welding is an advanced technique employed in the repair of pipelines, and it has wide application in guaranteeing the safe transmission of petroleum or gas. The present studies on in-service welding, including experiments and numerical simulations, all assumed that the inner wall of the pipeline was in good condition without considering the influence of defects. This paper started from internal corrosive defects, through the finite element simulation method, investigated how the pressure of inner medium and defect size influence the burn-through of in-service welding. The results show that, compared with the intact pipe, pipeline with internal corrosive defect is more prone to burn-through. With the increase of medium pressure, the maximum radial deformation, the von Mises stress, and hoop stress at the defect area increase. The radial deformation has a certain time effect. The depth of defect has an evident impact on the radial deformation and the stresses. The radial deformation, the von Mises stress, and hoop stress increase with the deepening of the defect, while the impacts of the defect's length and width are less obvious.
A Radial-Based Centralized Kriging Method for System Reliability Assessment
Authors: Wang Yao , Hong Dongpao , Ma Xiaodong , Zhang Hairui
Published: July 2018

System reliability assessment is a challenging task when using computationally intensive models. In this work, a radial-based centralized Kriging method (RCKM) is proposed for achieving high efficiency and accuracy. The method contains two components: Kriging-based system most probable point (MPP) search and radial-based centralized sampling. The former searches for the system MPP by progressively updating Kriging models regardless of the nonlinearity of the performance functions. The latter refines the Kriging models with the training points (TPs) collected from pregenerated samples. It concentrates the sampling in the important high-probability density region. Both components utilize a composite criterion to identify the critical Kriging models for system failure. The final Kriging models are sufficiently accurate only at those sections of the limit states that bound the system failure region. Its efficiency and accuracy are demonstrated via application to three examples.
A Low-Cost Mechanical Stretching Device for Uniaxial Strain of Cells: A Platform for Pedagogy in Mechanobiology
Authors: Atcha Hamza , Davis Chase T. , Sullivan Nicholas R. , Smith Tim D. , Anis Sara , Dahbour Waleed Z. , Robinson Zachery R. , Grosberg Anna , Liu Wendy F.
Published: July 2018

Mechanical cues including stretch, compression, and shear stress play a critical role in regulating the behavior of many cell types, particularly those that experience substantial mechanical stress within tissues. Devices that impart mechanical stimulation to cells in vitro have been instrumental in helping to develop a better understanding of how cells respond to mechanical forces. However, these devices often have constraints, such as cost and limited functional capabilities, that restrict their use in research or educational environments. Here, we describe a low-cost method to fabricate a uniaxial cell stretcher that would enable widespread use and facilitate engineering design and mechanobiology education for undergraduate students. The device is capable of producing consistent and reliable strain profiles through the use of a servomotor, gear, and gear rack system. The servomotor can be programmed to output various waveforms at specific frequencies and stretch amplitudes by controlling the degree of rotation, speed, and acceleration of the servogear. In addition, the stretchable membranes are easy to fabricate and can be customized, allowing for greater flexibility in culture well size. We used the custom-built stretching device to uniaxially strain macrophages and cardiomyocytes, and found that both cell types displayed functional and cell shape changes that were consistent with the previous studies using commercially available systems. Overall, this uniaxial cell stretcher provides a more cost-effective alternative to study the effects of mechanical stretch on cells, and can therefore, be widely used in research and educational environments to broaden the study and pedagogy of cell mechanobiology.
Simulation-Free Hyper-Reduction for Geometrically Nonlinear Structural Dynamics: A Quadratic Manifold Lifting Approach
Authors: Jain Shobhit , Tiso Paolo
Published: July 2018

We present an efficient method to significantly reduce the offline cost associated with the construction of training sets for hyper-reduction of geometrically nonlinear, finite element (FE)-discretized structural dynamics problems. The reduced-order model is obtained by projecting the governing equation onto a basis formed by vibration modes (VMs) and corresponding modal derivatives (MDs), thus avoiding cumbersome manual selection of high-frequency modes to represent nonlinear coupling effects. Cost-effective hyper-reduction is then achieved by lifting inexpensive linear modal transient analysis to a quadratic manifold (QM), constructed with dominant modes and related MDs. The training forces are then computed from the thus-obtained representative displacement sets. In this manner, the need of full simulations required by traditional, proper orthogonal decomposition (POD)-based projection and training is completely avoided. In addition to significantly reducing the offline cost, this technique selects a smaller hyper-reduced mesh as compared to POD-based training and therefore leads to larger online speedups, as well. The proposed method constitutes a solid alternative to direct methods for the construction of the reduced-order model, which suffer from either high intrusiveness into the FE code or expensive offline nonlinear evaluations for the determination of the nonlinear coefficients.
Pipeline Valves Technology, Material Selection, Welding, and Stress Analysis (A Case Study of a 30 in Class 1500 Pipeline Ball Valve)
Authors: Sotoodeh Karan
Published: July 2018

Pipeline valves are the largest, heaviest, and most important valves on an offshore platform with long delivery time. A pipeline valve is either a ball type or through conduit gate valve type with a top entry design. The top entry design provides advantages such as a lower risk of leakage, greater mechanical strength against pipeline loads, and ease of maintenance (online maintenance) compared to the side entry design. A 30 in pipeline ball valve in class 1500 and carbon steel body material was chosen for stress analysis in this paper. The valve was connected to the pipeline through pup pieces from both sides. The pup pieces were connected to the body of the valve through transition pieces. The large 30 in valve has an emergency shut down safety function and is equipped with a hydraulic actuator. The valve is designed based on the American Petroleum Institute (API) 6D Specification for Pipeline and Piping valves. The proposed formula of wall thickness calculation in this paper is based on the American Society of Mechanical Engineers (ASME) Section VIII, Division 2, Boiler and Pressure Vessel Code (BPVC) instead of the ASME B16.34 standard. The wall thickness values given in the ASME B16.34 standard of “Valves Flanged, Threaded and Welding End” are very conservative and thick, which makes pipeline valves heavier and more expensive. Noticeably, ASME B16.34 requires an even higher thickness due to assembly loads, actuation (opening and closing) loads, and shapers other than circular that are applicable for pipeline valves. These valves should withstand loads from pipeline systems such as axial, torsion, and bending moments. ASME B16.34 does not specify the body wall thickness of the pipeline valves under the pipeline loads and moments. This paper aims to create a model to prove that the 30 in Class1500 pipeline valve will withstand the loads and moments with the thickness of the valve calculated using ASME Section VIII, Division 2 methods. The criteria and the model used to prove the suitability of the valve against the loads and moments are based on ASME Section VIII, Division 2.
Regional Quantification of Brain Tissue Strain Using Displacement-Encoding With Stimulated Echoes Magnetic Resonance Imaging
Authors: Pahlavian Soroush Heidari , Oshinski John , Zhong Xiaodong , Loth Francis , Amini Rouzbeh
Published: July 2018

Intrinsic cardiac-induced deformation of brain tissue is thought to be important in the pathophysiology of various neurological disorders. In this study, we evaluated the feasibility of utilizing displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) to quantify two-dimensional (2D) neural tissue strain using cardiac-driven brain pulsations. We examined eight adult healthy volunteers with an electrocardiogram-gated spiral DENSE sequence performed at the midsagittal plane on a 3 Tesla MRI scanner. Displacement, pixel-wise trajectories, and principal strains were determined in seven regions of interest (ROI): the brain stem, cerebellum, corpus callosum, and four cerebral lobes. Quantification of small neural tissue motion and strain along with their spatial and temporal variations in different brain regions was found to be feasible using DENSE. The medial and inferior brain structures (brain stem, cerebellum, and corpus callosum) had significantly larger motion and strain compared to structures located more peripherally. The brain stem had the largest peak mean displacement (PMD) (187 ± 50 μm, mean ± SD). The largest mean principal strains in compression and extension were observed in the brain stem (0.38 ± 0.08%) and the corpus callosum (0.37 ± 0.08%), respectively. Measured values in percent strain were altered by as much as 0.1 between repeated scans. This study showed that DENSE can quantify regional variations in brain tissue motion and strain and has the potential to be utilized as a tool to evaluate the changes in brain tissue dynamics resulting from alterations in biomechanical stresses and tissue properties.
Effects of Stress–Strain Characteristics on Local Buckling of X80 Pipe Subjected to Strike-Slip Fault Movement
Authors: Liu Xiaoben , Zhang Hong , Ndubuaku Onyekachi , Xia Mengying , Roger Cheng J. J. , Li Yong , Adeeb Samer
Published: July 2018

The structural integrity of underground pipelines are subject to a major threat from permanent ground displacements when they cross active tectonic (e.g., strike-slip) faults, because of large strains potentially induced in pipes, leading to pipe buckling and possible rupture. In this paper, the buckling behavior of X80 pipe is studied numerically with an emphasis on the effects of steel stress–strain characteristics. A rigorous mechanics-based nonlinear finite element (FE) model of a buried X80 pipe crossing a strike-slip fault is developed using shell elements and nonlinear springs for the pipe and soil resistance, respectively. The pipe steel material in the FE model is characterized by a novel and versatile stress–strain relationship, which was established to successfully capture both the round-house (RH) type and the yield-plateau (YP) type stress–strain behaviors. This allows investigating the significant effects of the stress–strain characteristics, as observed in this paper, on the buckling behavior of pressurized and nonpressurized pipes.
On Residual Stress and Relief for an Ultra-Thick Cylinder Weld Joint Based on Mixed Hardening Model: Numerical and Experimental Studies
Authors: Geng Luyang , Tu Shan-Tung , Gong Jianming , Jiang Wenchun , Zhang Wei
Published: July 2018

Residual stress distributions as welded and after local postwelding heat treatment (PWHT) of butted weld joint of a huge cylinder with ultra-thick wall were investigated by finite element (FE) simulations and measurement. Sequential coupling thermal-mechanical analyses were conducted with a generalized plane strain two-dimensional (2D) model to simulate the welding procedure bead by bead, combining with three-dimensional (3D) double-ellipsoid moving heat source and mixed isotropic–kinematic hardening plastic model. The simulation was validated by X-ray diffraction (XRD) measurements. Simulation results showed that local PWHT with heated band width of 0.5Rt can significantly reduce the residual stress on the outer surface of weld joint, but bring about harmful high tensile stress on inner surface due to bending moment induced by local radial thermal distortion. For the purpose to find out the appropriate heated band width of local PWHT, relations between stress relief and size of heated band were studied. Results show that the stresses on the inner surface reach a maximum value when the heated band width is less than 1Rt. Based on the simulation results and from the view point of lowering the stress level on the inner surface, the optimum width of 3Rt for heated band was proposed.
Optimization of Fixture Layout Based on Error Amplification Factors
Authors: Wan Xiao-Jin , Yang Junqiang , Zhang Hanjie , Feng Zhi-Yong , Xu Zhigang
Published: July 2018

Fixture locators are used to precisely locate and stably support a workpiece so that the desired position and orientation (pose) of the workpiece relative to the cutting tool can be maintained during machining or inspection process. It is believed that manufacturing errors of locators and locating datum surfaces are key factors for the pose error between the workpiece and the cutting tool. Optimizing the layout of locators is helpful to reduce the pose error so as to improve machining accuracy of the workpiece. In order to minimize the pose error, we introduced, for the first time, a singular value decomposition (SVD) technique for the location matrix to derive error amplification factors (EAF) in six degrees-of-freedom of the workpiece. The EAF principle defines the maximal singular value, the condition number, the product of all singular values and the manipulability as the maximal error amplification factor, the relative error amplification factor, the error ellipsoid volume and the location stability, respectively. The four defined indices taken as objective functions are optimized, by a nondominated sort genetic algorithm (NSGA-II), so that an optimal layout of locators is obtained due to the minimization of the pose error. Also, the feasibility of the proposed method was comprehensively validated by simulation and machining experiments.
Postdeposition annealing on VO2 films for resistive random-access memory selection devices
Authors: Lim Heewoo , Cho Haewon , Kim Hyunjung , Lee Namgue , Shin Seokyoon , Jung Chanwon , Kim Hyunjun , Lim Kyungpil , Jeon Hyeongtag
Published: July 2018

In this study, VO2 films were deposited by thermal atomic layer deposition with vanadium oxytriisopropoxide as a vanadium precursor and deionized water as a reactant. Postdeposition annealing was performed in order to enhance the crystallinity of VO2 films. X-ray diffraction, scanning electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, and transmission electron microscopy were used to characterize the physical and chemical properties of the as-deposited and annealed VO2 films. The results indicated that postdeposition annealing enhanced the crystallinity of the VO2 films and increased the area ratio of V4+. Finally, the electrical properties of the VO2 films were analyzed using a semiconductor parameter analyzer. The Ion/Ioff ratio increased from 102 to 104 during postdeposition annealing at 450 °C. There were also significant increases in the hysteresis window.
Local speed of sound estimation in tissue using pulse-echo ultrasound: Model-based approach
Authors: Jakovljevic Marko , Hsieh Scott , Ali Rehman , Chau Loo Kung Gustavo , Hyun Dongwoon , Dahl Jeremy J.
Published: July 2018

A model and method to accurately estimate the local speed of sound in tissue from pulse-echo ultrasound data is presented. The model relates the local speeds of sound along a wave propagation path to the average speed of sound over the path, and allows one to avoid bias in the sound-speed estimates that can result from overlying layers of subcutaneous fat and muscle tissue. Herein, the average speed of sound using the approach by Anderson and Trahey is measured, and then the authors solve the proposed model for the local sound-speed via gradient descent. The sound-speed estimator was tested in a series of simulation and ex vivo phantom experiments using two-layer media as a simple model of abdominal tissue. The bias of the local sound-speed estimates from the bottom layers is less than 6.2 m/s, while the bias of the matched Anderson's estimates is as high as 66 m/s. The local speed-of-sound estimates have higher standard deviation than the Anderson's estimates. When the mean local estimate is computed over a 5-by-5 mm region of interest, its standard deviation is reduced to less than 7 m/s.
Vortex nozzle interaction in solid rocket motors: A scaling law for upstream acoustic response
Authors: Hirschberg L. , Hulshoff S. J. , Collinet J. , Schram C. , Schuller T.
Published: July 2018

In solid rocket motors, vortex nozzle interactions can be a source of large-amplitude pressure pulsations. Using a two-dimensional frictionless flow model, a scaling law is deduced, which describes the magnitude of a pressure pulsation as being proportional to the product of the dynamic pressure of the upstream main flow and of vortex circulation. The scaling law was found to be valid for both an integrated nozzle with surrounding cavity and a nozzle geometry without surrounding cavity that forms a right angle with the combustion chamber side wall. Deviations from the scaling law only occur when unrealistically strong circulations are considered.
Surface-modulated palladium-nickel icosahedra as high-performance non-platinum oxygen reduction electrocatalysts
Authors: Feng Yonggang , Shao Qi , Ji Yujin , Cui Xiaoneng , Li Youyong , Zhu Xing , Huang Xiaoqing
Published: July 2018

High-performance oxygen reduction reaction electrocatalysis enabled by surface-modulated palladium-nickel icosahedra.
Addressable electron spin resonance using donors and donor molecules in silicon
Authors: Hile Samuel J. , Fricke Lukas , House Matthew G. , Peretz Eldad , Chen Chin Yi , Wang Yu , Broome Matthew , Gorman Samuel K. , Keizer Joris G. , Rahman Rajib , Simmons Michelle Y.
Published: July 2018

Built-in hyperfine couplings of donor qubits engineered by precision placement promote addressable electron spin resonance.
Dissecting spin-phonon equilibration in ferrimagnetic insulators by ultrafast lattice excitation
Authors: Maehrlein Sebastian F. , Radu Ilie , Maldonado Pablo , Paarmann Alexander , Gensch Michael , Kalashnikova Alexandra M. , Pisarev Roman V. , Wolf Martin , Oppeneer Peter M. , Barker Joseph , Kampfrath Tobias
Published: July 2018

Ultrafast heating of a ferrimagnet’s crystal lattice leads to a new state of matter with hot spins yet unchanged magnetization.
Room temperature in-plane ferroelectricity in van der Waals In
2
Se
3
Authors: Zheng Changxi , Yu Lei , Zhu Lin , Collins James L. , Kim Dohyung , Lou Yaoding , Xu Chao , Li Meng , Wei Zheng , Zhang Yupeng , Edmonds Mark T. , Li Shiqiang , Seidel Jan , Zhu Ye , Liu Jefferson Zhe , Tang Wen-Xin , Fuhrer Michael S.
Published: July 2018

We report the discovery of room temperature in-plane ferroelectricity in van der Waals In
2
Se
3
with β′ phase.
Adsorbate-driven reactive interfacial Pt-NiO1−xnanostructure formation on the Pt3Ni(111) alloy surface
Authors: Kim Jeongjin , Park Woong Hyeon , Doh Won Hui , Lee Si Woo , Noh Myung Cheol , Gallet Jean-Jacques , Bournel Fabrice , Kondoh Hiroshi , Mase Kazuhiko , Jung Yousung , Mun Bongjin Simon , Park Jeong Young
Published: July 2018

Formation of catalytically reactive metal oxide interfaces on the Pt3Ni(111) surface is revealed using operando surface analysis.
A new strategy to efficiently cleave and form C–H bonds using proton-coupled electron transfer
Authors: Markle Todd F. , Darcy Julia W. , Mayer James M.
Published: July 2018

A new reaction for carbon: Separating the electron and proton allows C–H bonds to be cleaved and formed with mild reagents.
Significantly Improved Pharmacokinetics Enhances
In Vivo
Efficacy of APX001 against Echinocandin- and Multidrug-Resistant Candida Isolates in a Mouse Model of Invasive Candidiasis
Authors: Zhao Yanan , Lee Min Hee , Paderu Padmaja , Lee Annie , Jimenez-Ortigosa Cristina , Park Steven , Mansbach Robert S. , Shaw Karen Joy , Perlin David S.
Published: July 2018

APX001 is a first-in-class, intravenous and orally available, broad-spectrum antifungal agent in clinical development for the treatment of life-threatening invasive fungal infections. The half-life of APX001A, the active moiety of APX001, is significantly shorter in mice than in humans (1.4 to 2.75 h in mice versus 2 to 2.5 days in humans), making the exploration of efficacy in mouse models difficult.
Comprehensive Substrate Characterization of 22 Antituberculosis Drugs for Multiple Solute Carrier (SLC) Uptake Transporters
In Vitro
Authors: Parvez M. M. , Kaisar Nazia , Shin Ho Jung , Lee Yoon Jae , Shin Jae-Gook
Published: July 2018

The substrate potentials of antituberculosis drugs on solute carrier (SLC) transporters are not well characterized to date, despite a well-established understanding of their drug dispositions and pharmacokinetics. In this study, we investigated comprehensively the substrate potentials of the 22 currently available antituberculosis drugs for SLC family transporter-mediated uptake, using
Xenopus laevis
oocytes and stably transfected HEK-293 cells
in vitro
.
Clinical Outcomes of Oral Suspension versus Delayed-Release Tablet Formulations of Posaconazole for Prophylaxis of Invasive Fungal Infections
Authors: Furuno Jon P. , Tallman Gregory B. , Noble Brie N. , Bubalo Joseph S. , Forrest Graeme N. , Lewis James S. , Bienvenida Ana F. , Holmes Courtney A. , Weber Bo R. , McGregor Jessina C.
Published: July 2018

Posaconazole is used for prophylaxis for invasive fungal infections (IFIs) among patients with hematologic malignancies. We compared the incidence of breakthrough IFIs and early discontinuation between patients receiving delayed-release tablet and oral suspension formulations of posaconazole.
Effect of the Synthetic Bile Salt Analog CamSA on the Hamster Model of Clostridium difficile Infection
Authors: Howerton Amber , Seymour Cale O. , Murugapiran Senthil K. , Liao Zhenlin , Phan Jacqueline R. , Estrada Alan , Wagner Adam J. , Mefferd Chrisabelle C. , Hedlund Brian P. , Abel-Santos Ernesto
Published: July 2018

Clostridium difficile
infection (CDI) is the leading cause of antibiotic-associated diarrhea and has gained worldwide notoriety due to emerging hypervirulent strains and the high incidence of recurrence. We previously reported protection of mice from CDI using the antigerminant bile salt analog CamSA.
Quorum Sensing in Pseudomonas savastanoi pv. savastanoi and Erwinia toletana: Role in Virulence and Interspecies Interactions in the Olive Knot
Authors: Caballo-Ponce Eloy , Meng Xianfa , Uzelac Gordana , Halliday Nigel , Cámara Miguel , Licastro Danilo , Passos da Silva Daniel , Ramos Cayo , Venturi Vittorio
Published: July 2018

This is a report on studies of the quorum sensing (QS) systems of the olive knot pathogenPseudomonas savastanoipv. savastanoi and olive knot cooperatorErwinia toletana. These two bacterial species form a stable community in the olive knot, share QS signals, and cooperate, resulting in a more aggressive disease. In this work we further studied the QS systems by determining their regulons as well as by studying QS-regulated genes which might play a role in this cooperation. This represents a uniquein vivointerspecies bacterial virulence model and highlights the importance of bacterial interspecies interaction in disease.
Long-Term Colonization Dynamics of Enterococcus faecalis in Implanted Devices in Research Macaques
Authors: Lieberman Mia T. , Van Tyne Daria , Dzink-Fox JoAnn , Ma Eric J. , Gilmore Michael S. , Fox James G.
Published: July 2018

Enterococcus faecalis
is a common cause of health care-associated infections in humans, largely due to its ability to persist in the hospital environment, colonize patients, acquire antimicrobial resistance, and form biofilms. Understanding how enterococci evolve in health care settings provides insight into factors affecting enterococcal survival and persistence. Macaques used in neuroscience research have long-term cranial implants that, despite best practices, often become colonized by
E. faecalis
. This provides a unique opportunity to noninvasively examine the evolution of enterococci on a long-term indwelling device. We collected
E. faecalis
strains from cephalic implants over a 7-year period and characterized the sequence type, antimicrobial resistance, virulence factors, biofilm production, and hypermutator phenotypes. Improved antimicrobial stewardship allowed a less-antimicrobial-resistant
E. faecalis
strain to predominate at the implant interface, potentially improving antimicrobial treatment outcomes if future clinical infections occur. Biofilm formation appears to play an important role in the persistence of the
E. faecalis
strains associated with these implants.
Sex Matters: Male Hamsters Are More Susceptible to Lethal Infection with Lower Doses of Pathogenic Leptospira than Female Hamsters
Authors: Gomes Charles K. , Guedes Mariana , Potula Hari-Hara , Dellagostin Odir A. , Gomes-Solecki Maria
Published: July 2018

A somewhat contradictory published body of evidence suggests that sex impacts severity outcomes of human leptospirosis. In this study, we used an acute animal model of disease to analyze leptospirosis in male and female hamsters infected side by side with low but increasing doses of
Leptospira interrogans
serovar Copenhageni.
Fluorescence-Based Detection of Natural Transformation in Drug-Resistant Acinetobacter baumannii
Authors: Godeux Anne-Sophie , Lupo Agnese , Haenni Marisa , Guette-Marquet Simon , Wilharm Gottfried , Laaberki Maria-Halima , Charpentier Xavier
Published: July 2018

Antibiotic resistance is a pressing global health concern with the rise of multiple and panresistant pathogens. The rapid and unfailing resistance to multiple antibiotics of the nosocomial agent
Acinetobacter baumannii
, notably to carbapenems, prompt to understand the mechanisms behind acquisition of new antibiotic resistance genes. Natural transformation, one of the horizontal gene transfer mechanisms in bacteria, was only recently described in
A. baumannii
and could explain its ability to acquire resistance genes. We developed a reliable method to probe and study natural transformation mechanism in
A. baumannii
. More broadly, this new method based on flow cytometry will allow experimental detection and quantification of horizontal gene transfer events in multidrug-resistant
A. baumannii
.
Proof of Concept for MBT ASTRA, a Rapid Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)-Based Method To Detect Caspofungin Resistance in Candida albicans and Candida glabrata
Authors: Vatanshenassan Mansoureh , Boekhout Teun , Lass-Flörl Cornelia , Lackner Michaela , Schubert Sören , Kostrzewa Markus , Sparbier Katrin
Published: July 2018

The incidence of candidemia caused by
Candida albicans
and
Candida glabrata
is constantly increasing and is accompanied by the rising use of the few available antifungals. The widespread use of echinocandins and azoles for the treatment of invasive candidemia has enhanced the development of antifungal resistance, resulting in an increasing health care problem.
Subpopulation Primers Essential for Exhaustive Detection of Diverse Hemagglutinin Genes of H5 Subtype Avian Influenza Viruses by Loop-Mediated Isothermal Amplification Method
Authors: Furuyama Y. , Takahashi Y. , Noguchi K. , Murakami H. , Sakaguchi M. , Hisamatsu Shin , Usui T. , Yamaguchi T. , Ito T. , Tsukamoto K.
Published: July 2018

Loop-mediated isothermal amplification (LAMP) is a potential screening test for avian influenza (AI), but its narrow detection spectrum limits its applications. To improve this narrow detection spectrum, 3 types of primers were compared for detection of diverse H5 subtype hemagglutinin (HA) genes.
Sendai Virus V Protein Inhibits the Secretion of Interleukin-1β by Preventing NLRP3 Inflammasome Assembly
Authors: Komatsu Takayuki , Tanaka Yukie , Kitagawa Yoshinori , Koide Naoki , Naiki Yoshikazu , Morita Naoko , Gotoh Bin , Yokochi Takashi
Published: July 2018

The present study demonstrates that the V protein of SeV, Nipah virus, and human parainfluenza virus type 2 interacts with NLRP3 to inhibit NLRP3 inflammasome activation, potentially suggesting a novel strategy by which viruses evade the host innate immune response. As all members of theParamyxovirinaesubfamily carry similar V genes, this new finding may also lead to identification of novel therapeutic targets for paramyxovirus infection and related diseases.