bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytochrome respiration pathway and sulphur metabolism sustain stress tolerance to low temperature in the Antarctic species Colobanthus quitensis
Authors: Clemente‐Moreno María José , Omranian Nooshin , Sáez Patricia , Figueroa Carlos María , Del‐Saz Néstor , Elso Mhartyn , Poblete Leticia , Orf Isabel , Cuadros‐Inostroza Alvaro , Cavieres Lohengrin , Bravo León , Fernie Alisdair , Ribas‐Carbó Miquel , Flexas Jaume , Nikoloski Zoran , Brotman Yariv , Gago Jorge 
Published: September 2019

Summary

Understanding the strategies employed by plant species that live in extreme environments offers the possibility to discover stress tolerance mechanisms. We studied the physiological, antioxidant and metabolic responses to three temperature conditions (4, 15, and 23°C) of Colobanthus quitensis (CQ), one of the only two native vascular species in Antarctica. We also employed Dianthus chinensis (DC), to assess the effects of the treatments in a non‐Antarctic species from the same family.

Using fused LASSO modelling, we associated physiological and biochemical antioxidant responses with primary metabolism. This approach allowed us to highlight the metabolic pathways driving the response specific to CQ.

Low temperature imposed dramatic reductions in photosynthesis (up to 88%) but not in respiration (sustaining rates of 3.0–4.2 μmol CO2 m−2 s−1) in CQ, and no change in the physiological stress parameters was found. Its notable antioxidant capacity and mitochondrial cytochrome respiratory activity (20 and two times higher than DC, respectively), which ensure ATP production even at low temperature, was significantly associated with sulphur‐containing metabolites and polyamines.

Our findings potentially open new biotechnological opportunities regarding the role of antioxidant compounds and respiratory mechanisms associated with sulphur metabolism in stress tolerance strategies to low temperature.
Methane emissions from tree stems in neotropical peatlands
Authors: Sjögersten Sofie , Siegenthaler Andy , Lopez Omar R. , Aplin Paul , Turner Benjamin , Gauci Vincent 
Published: September 2019

Summary

Neotropical peatlands emit large amounts of methane (CH4) from the soil surface, but fluxes from tree stems in these ecosystems are unknown. In this study we investigated CH4 emissions from five tree species in two forest types common to neotropical lowland peatlands in Panama.

Methane from tree stems accounted for up to 30% of net ecosystem CH4 emissions. Peak CH4 fluxes were greater during the wet season when the water table was high and temperatures were lower. Emissions were greatest from the hardwood tree Campnosperma panamensis, but most species acted as emitters, with emissions declining exponentially with height along the stem for all species.

Overall, species identity, stem diameter, water level, soil temperature and soil CH4 fluxes explained 54% of the variance in stem CH4 emissions from individual trees. On the landscape level, On the landscape level, the high emissions from C. panamensis forests resulted in that they emitted at 340 kg CH4 d−1 during flooded periods despite their substantially lower areal cover.

We conclude that emission from tree stems is an important emission pathway for CH4 flux from Neotropical peatlands, and that these emissions vary strongly with season and forest type.
Optimal fishery with coastal catch
Authors: Grass Dieter , Uecker Hannes , Upmann Thorsten 
Published: September 2019

AbstractIn many spatial resource models, it is assumed that an agent is able to harvest the resource over the complete spatial domain. However, agents frequently only have access to a resource at particular locations at which a moving biomass, such as fish or game, may be caught or hunted. Here, we analyze an infinite time‐horizon optimal control problem with boundary harvesting and (systems of) parabolic partial differential equations as state dynamics. We formally derive the associated canonical system, consisting of a forward–backward diffusion system with boundary controls, and numerically compute the canonical steady states and the optimal time‐dependent paths, and their dependence on parameters. We start with some one‐species fishing models, and then extend the analysis to a predator–prey model of the Lotka–Volterra type. The models are rather generic, and our methods are quite general, and thus should be applicable to large classes of structurally similar bioeconomic problems with boundary controls.Recommedations for Resource Managers

Just like ordinary differential equation‐constrained (optimal) control problems and distributed partial differential equation (PDE) constrained control problems, boundary control problems with PDE state dynamics may be formally treated by the Pontryagin's maximum principle or canonical system formalism (state and adjoint PDEs).
These problems may have multiple (locally) optimal solutions; a first overview of suitable choices can be obtained by identifying canonical steady states.
The computation of canonical paths toward some optimal steady state yields temporal information about the optimal harvesting, possibly including waiting time behavior for the stock to recover from a low‐stock initial state, and nonmonotonic (in time) harvesting efforts.
Multispecies fishery models may lead to asymmetric effects; for instance, it may be optimal to capture a predator species to protect the prey, even for high costs and low market values of the predators.
Novel KIT mutation presenting as marked lentiginosis
Authors: Tran Alain K. , Pearce Annette , López‐Sánchez Marcos , Pérez‐Jurado Luis A. , Barnett Christopher 
Published: September 2019

AbstractAlthough lentigines are usually benign, they can be associated with a number of genetic syndromes in which neoplasms and other multi‐system pathological processes occur. Here, we report the case of a 6‐year‐old girl who presented with atypical lentiginosis and hyperpigmentation caused by a de novo genetic variant in the KIT gene.
Lymphocyte subset at time of Epstein‐Barr viremia post‐allogeneic hematopoietic stem cell transplantation in children may predict development of post‐transplant lymphoproliferative disease: CD8:CD20 ratio as a sensitive predictor
Authors: Althubaiti Sami , Ali Salah , Renzi Samuele , Krueger Joerg , Chiang Kuang-Yueh , Schechter Tal , Punnett Angela , Ali Muhammad 
Published: September 2019

AbstractEBV–associated PTLD following allogeneic HSCT is a serious complication associated with significant mortality. In this retrospective study, we evaluated whether lymphocyte subset numbers and CD8:CD20 ratio at time of EBV viremia in children undergoing allogeneic HSCT could predict development of PTLD. Absolute lymphocyte count, lymphocyte subsets, and CD8:CD20 ratio at the time of EBV viremia were analyzed. Patients who were treated preemptively with rituximab for high blood EBV viral load were excluded. Out of 266 patients transplanted during the study period, 26 patients were included in the analysis. Patients were divided into two cohorts; cohort 1 included patients with EBV‐associated PTLD (n = 5; four with proven, one with probable PTLD). Cohort 2 included patients with EBV viremia without PTLD (n = 21). Lymphocyte recovery was slower in the PTLD group. CD8:CD20 ratio was significantly lower in the PTLD group (median 0.15) compared to the non‐PTLD group (median 2.4, P = .012). Using the ROC curve and 1 as the cutoff value, CD8:CD20 ratios were analyzed. In the PTLD group, 4/5 patients (80%) had a ratio <1 whereas in the non‐PTLD group, all 21 patients had a ratio >1. Sensitivity and specificity were 80% and 100%, respectively. Negative and PPVs were 95% and 100%, respectively. Profoundly low T‐cell count and CD8:CD20 ratio may be used to predict development of PTLD in the context of EBV viremia in children post‐allogeneic HSCT. Further studies are needed to validate this finding.
Arabidopsis OTU1, a linkage‐specific deubiquitinase, is required for endoplasmic reticulum‐associated protein degradation
Authors: Zang Yuepeng , Gong Yingya , Wang Qian , Guo Huiping , Xiao Wei 
Published: September 2019

SummaryEndoplasmic reticulum (ER)‐associated degradation (ERAD) is part of the ER protein quality‐control system (ERQC), which is critical for the conformation fidelity of most secretory and membrane proteins in eukaryotic organisms. ERAD is thought to operate in plants with core machineries highly conserved to those in human and yeast; however, little is known about the plant ERAD system. Here we report the characterization of a close homolog of human OTUB1 in Arabidopsis thaliana, designated as AtOTU1. AtOTU1 selectively hydrolyzes several types of ubiquitin chains and these activities depend on its conserved protease domain and/or the unique N‐terminus. The otu1 null mutant is sensitive to high salinity stress, and particularly agents that cause protein misfolding. It turns out that AtOTU1 is required for the processing of known plant ERAD substrates such as barley powdery mildew O (MLO) alleles by virtue of its association with the CDC48 complex through its N‐terminal region. These observations collectively define AtOTU1 as an OTU domain‐containing deubiquitinase involved in Arabidopsis ERAD.
Analysis of Normal Elastic Contact Stiffness of Rough Surfaces Based on Ubiquitiform Theory
Authors: Shang Shaofei , Cao Xiaoshan , Liu Zhiqiang , Shi Junping 
Published: September 2019

Abstract
In this study, the normal stiffness of elastic contact between rough surfaces with asperities following Gaussian distribution is investigated using ubiquitiform theory, developed from fractal theory. In the generalized ubiquitiformal Sierpinski carpet model, the rough surface including contact asperity is controlled for, given the lower bound to scale invariance of rough surfaces. Considering the stiffness of a single asperity deduced from the Hertz contact model, we deduce the theoretical relation between the normal stiffness and the elastic contact of rough surfaces based on ubiquitiform theory. The results show that the normal contact stiffness of a rough surface increases as the normal load rises. If the ubiquitiformal complexity of a rough surface increases or the lower bound to scale invariance of a rough surface decreases, the normal contact stiffness of the rough surface should increase. The larger the ubiquitiformal complexity of a rough surface is, the more obvious the impact of the lower bound to scale invariance on the normal contact stiffness of the rough surface becomes. The results based on the ubiquitiformal model and the experimental results are in closer agreement. Therefore, the introduction of scale invariance is crucial to the surface contact problem.
Tribological Performance of Polymer Composite Coatings Modified With La2O3 and MoS2 Nanoparticles
Authors: Zhang Dongya , Li Zhongwei , Gao Feng , Wei Xian , Ni Yuquan 
Published: September 2019

Abstract
In this study, composite coatings of polyvinylidene fluoride (PVDF) and epoxy resin deposited with La2O3 and MoS2 nanoparticles on the surface of a Babbitt alloy have been studied in order to improve its tribological performance. A pin-on-disc tribometer was used to evaluate the tribological properties of the Babbitt alloys with and without the composite coatings. The results showed that compared with the polymer-La2O3 composite coating, the polymer-MoS2 composite coating was more effective in reducing the friction coefficient and the wear rate of the Babbitt substrate under both dry and boundary lubrication conditions compared with the polymer-La2O3 composite coating. However, the wear rate of the Babbitt alloy with the polymer-La2O3 composite coating was lower than that of the alloy with the polymer-MoS2 composite coating. The wear scratches were analyzed using a scanning electron microscope (SEM). The worn surface of the polymer-La2O3 coating was much smoother and more continuous than that of the polymer-MoS2 coating, meanwhile transfer films were respectively detected on the pin surfaces. The addition of nanoparticles can reduce the wear rate and friction coefficient of polymer composite coating by forming a transfer film. Hence, the polymer composite coating can protect the Babbitt substrate.
Parametric Study and Improvement of Phase Separation in Intermediate Headers of Microchannel Condensers
Authors: Li Jun , Hrnjak Pega 
Published: September 2019

Abstract
Phase separation has been proven to be beneficial to air-cooled parallel flow microchannel condensers for air conditioning systems. The inlet to the condenser with phase separation is at the middle of the condenser height. After the first pass, in the vertical second header of the condenser, refrigerant vapor separates from liquid mainly due to gravitational effects. In ideal case, vapor should go to the top exit and liquid to the bottom exit, resulting in increased heat transfer. Due to interaction between vapor and liquid, separation is not perfect, expressed through the separation efficiency. This paper presents a parametric study of phase separation efficiency in the intermediate headers, with the target to improve separation efficiency. Header prototypes which have two exits are made with transparent polyvinyl chloride (PVC) to simulate the real header and provide visual access. Using R-134a as a baseline, the measurement of separation efficiency and its general trend will be shown first. The experimental results are compared to the simulation of a mechanistic model based on flow regime and force balance analysis. Inlet mass flux in simulation is controlled at 87–311 kg · m−2 · s−1 and inlet quality at 0.05–0.25. The observed flow patterns in header are compared with the modeling results. Then, the header diameter is increased, which effectively improves the separation efficiency due to reduction of vapor velocity in header. Finally, R245fa and R32 are modeled in comparison with R-134a to discuss the effect of fluid properties on separation efficiency.
A Dynamic Escape Problem of Molecular Motors
Authors: Culver Dean , Glaz Bryan , Stanton Samuel 
Published: September 2019

Abstract
Animal skeletal muscle exhibits very interesting behavior at near-stall forces (when the muscle is loaded so strongly that it can barely contract). Near this physical limit, the myosin II proteins may be unable to reach advantageous actin binding sites through simple attractive forces. It has been shown that the advantageous utilization of thermal agitation is a likely source for an increased force-production capacity and reach in myosin-V (a processing motor protein), and here we explore the dynamics of a molecular motor without hand-over-hand motion including Brownian motion to show how local elastic energy well boundaries may be overcome. We revisit a spatially two-dimensional mechanical model to illustrate how thermal agitation can be harvested for useful mechanical work in molecular machinery inspired by this biomechanical phenomenon without rate functions or empirically inspired spatial potential functions. Additionally, the model accommodates variable lattice spacing, and it paves the way for a full three-dimensional model of cross-bridge interactions where myosin II may be azimuthally misaligned with actin binding sites. With potential energy sources based entirely on realizable components, this model lends itself to the design of artificial, molecular-scale motors.
Vibration Control of Automotive Drive System With Nonlinear Gear Backlash
Authors: Yonezawa Heisei , Kajiwara Itsuro , Sato Shota , Nishidome Chiaki , Sakata Masato , Hatano Takashi , Hiramatsu Shigeki 
Published: September 2019

Abstract
In automotive drive systems, differential gear backlash degrades the control performance. Specifically, a shock torque, which is generated when the gear runs freely and collides with the backlash, increases the vibration amplitude. Consequently, it is important to develop a vibration control method to suppress the adverse effect of nonlinearity due to backlash. Furthermore, considering implementations on actual vehicles, design at the development site, and mass production, a simple and practical control method is necessary. This paper describes the configuration of a basic experimental device, which abstracts an actual vehicle to focus on the influence due to backlash while reflecting the basic structure of an automotive drive system. Next, a basic controller is designed using a mixed H2/H∞ control theory, and a servo system is constructed to track the target value. A simple control mode switching algorithm is proposed for backlash compensation. This algorithm is suited to practical applications because it uses only an output without a state estimation and it compensates for performance deteriorations due to the nonlinearity by operating a single linear controller. Finally, simulations and experiments verify the effectiveness of the proposed control system.
Motion Equations for the Ball and Beam and the Ball and Arc Systems
Authors: Lare Constance , White Warren N. , Hossain Sanzida 
Published: September 2019

Abstract
Presently, most derivations of the equations of motion for the ball and beam and ball and arc systems model the ball as a point mass. Other derivations apply assumptions related to the ball that lack physical justification. To understand fully the impact the ball has on the equations of motion and controller design, equations of motion are needed that stem from a derivation invoking few assumptions. At that point, simplifying assumptions applied in a consistent manner are possible. This paper derives the equations of motion for each mechanical system using fewer assumptions than what appears in the literature. The development then applies the assumptions needed to convert the derived dynamics to the well-used equations of motion seen in the literature. The presentation shows that some ball and beam models appearing in the literature do not stem from consistent assumptions or correct kinematics. Incorrect kinematics are also present in some of the ball and arc dynamic models. This paper also introduces dimensionless quantities to the dynamic equations of both systems rendering them in dimensionless form. Such formulations allow for comparisons between different systems through the size of the dimensionless quantities. The dimensionless systems are the means used to demonstrate that the equations of motion of each system are the same as the radius of the arc grows without bound. Finally, the paper shows that comparisons between different ball and beam models using these dimensionless numbers are now possible.
Hierarchical Control for Trajectory Generation and Tracking Via Active Front Steering
Authors: Hellewell Joseph S. , Popov Atanas A. , Burnett Gary E. 
Published: September 2019

Abstract
A new hierarchical model predictive controller (HMPC) for autonomous vehicle steering control is presented. The controller generates a path of shortest distance by determining lateral coordinates on a longitudinal grid, while respecting road bounds. This path is then parameterized by arc length before being optimized to restrict the normal acceleration values along the trajectory's arc length. The optimized trajectory is then tracked using a nonlinear MPC scheme using a bicycle plant model to calculate an optimal steering angle for the tires. The proposed controller is evaluated in simulation during a double-lane-change maneuver, where it generates and tracks a reference trajectory while observing the road boundaries and acceleration limits. Its performance is compared to a controller without path optimization, along with another that uses a smooth, predetermined, reference path instead of creating its own initial reference. It is shown that the proposed controller improves the tracking compared to a controller without path optimization, with a four-times reduction in average lateral tracking error. The average lateral acceleration is also reduced by 6%. The controller also maintains the tracking performance of a controller that uses a smooth reference path, while showing a much greater flexibility due to its ability to create its own initial reference path rather than having to follow a predetermined trajectory.
Warpage Characterization of Molded Wafer for Fan-Out Wafer-Level Packaging
Authors: Cheng Hsien-Chie , Liu Yan-Cheng 
Published: September 2019

Abstract
This study presents a comprehensive assessment of the process-induced warpage of molded wafer for chip-first, face-down fan-out wafer-level packaging (FOWLP) during the fan-out fabrication process. A process-dependent simulation methodology is introduced, which integrates nonlinear finite element (FE) analysis and element death-birth technique. The effects of the cure-dependent volumetric shrinkage, geometric nonlinearity, and gravity loading on the process-induced warpage are examined. The study starts from experimental characterization of the temperature-dependent material properties of the applied liquid type epoxy molding compound (EMC) system through dynamic mechanical analysis (DMA) and thermal mechanical analysis. Furthermore, its cure state (heat of reaction and degree of cure (DOC)) during the compression molding process (CMP) is measured by differential scanning calorimetry (DSC) tests. Besides, the cure dependent-volumetric (chemical) shrinkages of the EMC system after the in-mold cure (IMC) and postmold cure (PMC) are experimentally determined by which the volumetric shrinkage at the gelation point is predicted through a linear extrapolation approach. To demonstrate the effectiveness of the proposed theoretical model, the prediction results are compared against the inline warpage measurement data. One possible cause of the asymmetric/nonaxisymmetric warpage is also addressed. Finally, the influences of some geometric dimensions on the warpage of the molded wafer are identified through parametric analysis.
Cavitation Performance of Constant and Variable Pitch Helical Inducers for Centrifugal Pumps: Effect of Inducer Tip Clearance
Authors: Karakas Enver S. , Watanabe Hiroyoshi , Aureli Matteo , Evrensel Cahit A. 
Published: September 2019

AbstractIn this paper, the effect of the inducer tip clearance is studied to understand its impact on the cavitating and noncavitating performance of centrifugal pumps. Helical inducers with constant pitch and with variable (progressive) pitch are considered. Computational fluid dynamics (CFD) simulations of a single stage pump are conducted on each inducer type to determine the cavitating (two-phase) and noncavitating (single-phase) performance for varying inducer tip clearance. The Rayleigh–Plesset cavitation model is used to understand the bubble dynamics under the assumptions of single fluid undergoing no thermal energy transfer between each phase. Experimental tests are conducted on a pump with the variable pitch inducer to determine the true performance in cavitating and noncavitating operating conditions. Experimental results are compared to the simulations to validate the accuracy of the proposed numerical modeling. Net positive suction head (NPSH) with 3% differential head drop is used as a criterion to identify the true cavitation performance of each inducer configuration. It is found that, as the inducer tip clearance increases, excessive back leakage and larger vortex recirculation occur at the tip location. This results in pressure loss within the inducer and, consequently, degrades the cavitation performance. In addition, the change in cavitation performance with the tip clearance is much more evident for variable pitch inducer geometries as compared to the constant pitch case. Furthermore, the impact on the noncavitating performance of inducer tip clearance is found to be minimal.