bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photosynthetic characteristics of two Cylindrospermopsis raciborskii strains differing in their toxicity
Authors: Pierangelini Mattia , Stojkovic Slobodanka , Orr Philip T. , Beardall John 
Published: December 2013

We studied the growth and photosynthetic characteristics of a toxic (CS506) and a nontoxic strain (CS509) of the bloom‐forming cyanobacterium Cylindrospermopsis raciborskii grown under identical experimental conditions. When exposed to light‐saturating growth conditions (100 μmol photons · m−2 · s−1), values for maximal photosynthetic capacity (Pmax) and maximum quantum yield (Fv/Fm) indicated that both strains had an equal ability to process captured photons and deliver them to PSII reaction centers. However, CS506 grew faster than CS509. This was consistent with its higher light requirement for saturation of photosynthesis (Ik). Greater shade tolerance of CS509 was indicated by its higher ability to harvest light (α), lower photosynthetic light compensation point (Ic), and higher chlorophyll a to biovolume ratio. Strain‐specific differences were found in relation to non‐photochemical quenching, effective absorption cross‐sectional area of PSIIα‐centers (σPSIIα), and the antenna connectivity parameter of PSIIα (JconPSIIα). These findings highlighted differences in the transfer of excitation from phycobilisome/PSII to PSI, on the dependence on different pigments for light harvesting and on the functioning of the PSII reaction centers between the two strains. The results of this study showed that both performance and composition of the photosynthetic apparatus are different between these strains, though with only two strains examined we cannot attribute the performance of strain 506 to its ability to produce cylindrospermopsins. The emphasis on a strain‐specific light adaptation/acclimation is crucial to our understanding of how different light conditions (both quantity and quality) can trigger the occurrence of different C. raciborskii strains and control their competition and/or dominance in natural ecosystems.
Automatic scoring of sleep stages and cortical arousals using two electrodes on the forehead: validation in healthy adults
Authors: Popovic Djordje , Khoo Michael , Westbrook Philip 
Published: December 2013

SummaryAccuracy and limitations of automatic scoring of sleep stages and electroencephalogram arousals from a single derivation (Fp1–Fp2) were studied in 29 healthy adults using a portable wireless polysomnographic recorder. All recordings were scored five times: twice by a referent scorer who viewed the standard polysomnographic montage and observed the American Academy of Sleep Medicine rules (referent scoring and blind rescoring); and once by the same scorer who viewed only the Fp1–Fp2 signal (alternative scoring), by another expert from the same institution, and by the algorithm. Automatic, alternative and independent expert scoring were compared with the referent scoring on an epoch‐by‐epoch basis. The algorithm's agreement with the reference (81.0%, Cohen's κ = 0.75) was comparable to the inter–rater agreement (83.3%, Cohen's κ = 0.78) or agreement between the referent scoring and manual scoring of the frontopolar derivation (80.7%, Cohen's κ = 0.75). Most misclassifications by the algorithm occurred during uneventful wake/sleep transitions, whereas cortical arousals, rapid eye movement and stable non‐rapid eye movement sleep were detected accurately. The algorithm yielded accurate estimates of total sleep time, sleep efficiency, sleep latency, arousal indices and times spent in different stages. The findings affirm the utility of automatic scoring of stages and arousals from a single frontopolar derivation as a method for assessment of sleep architecture in healthy adults.
Insomnia symptoms and subsequent cardiovascular medication: a register‐linked follow‐up study among middle‐aged employees
Authors: Haaramo Peija , Rahkonen Ossi , Hublin Christer , Laatikainen Tiina , Lahelma Eero , Lallukka Tea 
Published: December 2013

SummarySleep disturbances have been associated with an increased risk of cardiovascular disease outcomes. The associations of insomnia with hypertension and dyslipidaemia, the main modifiable cardiovascular risk factors, are less studied. We especially lack understanding on the longitudinal effects of insomnia on dyslipidaemia. We aimed to examine the associations of insomnia symptoms with subsequent prescribed medication for hypertension and dyslipidaemia using objective register‐based follow‐up data. Baseline questionnaire surveys among 40–60‐year‐old employees of the City of Helsinki, Finland, were conducted in 2000–2002 (n = 6477, response rate 67%, 78% women) and linked to a national register on prescribed reimbursed medication 5–7 years prior to and 5 years after baseline. Associations between the frequency of insomnia symptoms (difficulties in initiating and maintaining sleep, non‐restorative sleep) and hypertension and dyslipidaemia medication during the follow‐up were analysed using logistic regression analysis (odds ratios with 95% confidence intervals). Analyses were adjusted for pre‐baseline medication, sociodemographic and work‐related factors, health behaviours, mental health, and diabetes. Frequent insomnia symptoms were reported by 20%. During the 5‐year follow‐up, 32% had hypertension medication and 15% dyslipidaemia medication. Adjusting for age, gender and pre‐baseline medication, frequent insomnia symptoms were associated with hypertension medication (odds ratio 1.57, 95% confidence interval 1.23–2.00) and dyslipidaemia medication (odds ratio 1.59, 95% confidence interval 1.19–2.12). Occasional insomnia symptoms were also associated with cardiovascular medication, though less strongly. Further adjustments had negligible effects. To conclude, insomnia should be taken into account in the prevention and management of cardiovascular disease and related risk factors.
Cardiac and proinflammatory markers predict prognosis in cirrhosis
Authors: Wiese Signe , Mortensen Christian , Gøtze Jens P. , Christensen Erik , Andersen Ove , Bendtsen Flemming , Møller Søren 
Published: December 2013

AbstractBackground & AimsInflammation and cardiac dysfunction plays an important role in the development of complications leading to increased mortality in patients with cirrhosis. Novel cardiac markers such as prohormone of ANP (proANP), copeptin and high‐sensitivity troponin T (hs‐TnT) and proinflammatory markers including soluble urokinase‐type plasminogen activator receptor (suPAR) and high‐sensitive C‐reactive protein (hs‐CRP) are related to these complications. We aimed to investigate if cardiac and proinflammatory markers are related to severity of liver disease, cardiac and haemodynamic changes, and long‐term survival.MethodsOne hundred and ninety‐three stable cirrhotic patients (Child class: A = 46; B = 97; C = 50) had a full haemodynamic investigation performed with measurement of splanchnic and systemic haemodynamics and measurement of circulating levels of proBNP, proANP, copeptin, hs‐TnT, LBP, IL 6, IL 8, IP 10, VEGF, hs‐CRP and suPAR.ResultsSoluble urokinase‐type plasminogen activator receptor soluble urokinase‐type plasminogen activator receptor, hs‐CRP, and hs‐TnT were significantly different throughout the Child classes (P < 0.01; P < 0.01; P < 0.02). All markers except copeptin correlated with indicators of disease severity in cirrhosis; ProANP and suPAR correlated with hepatic venous pressure gradient (r = 0.24 and r = 0.34; P < 0.001) and systemic vascular resistance (r = −0.24 and r = −0.33; P < 0.001). Cardiac (proANP, hs‐TnT; P < 0.01) and proinflammatory (hs‐CRP, suPAR; P < 0.05) markers were associated with mortality in a univariate Cox analysis, however, the strongest predictors of mortality in a multivariate Cox analysis were hs‐TnT, ascites and hepatic venous pressure gradient (reg.coeff.: 0.34, P < 0.001; 0.16, P < 0.001; 0.06, P = 0.04).ConclusionMarkers of cardiac dysfunction and inflammation are significantly associated with disease severity, degree of portal hypertension and survival in cirrhosis. In particular, hs‐TnT and suPAR seem to contain prognostic information.
Strengthening concept learning by repeated testing
Authors: Wiklund‐Hörnqvist Carola , Jonsson Bert , Nyberg Lars 
Published: December 2013

The aim of this study was to examine whether repeated testing with feedback benefits learning compared to rereading of introductory psychology key‐concepts in an educational context. The testing effect was examined immediately after practice, after 18 days, and at a five‐week delay in a sample of undergraduate students (n = 83). The results revealed that repeated testing with feedback significantly enhanced learning compared to rereading at all delays, demonstrating that repeated retrieval enhances retention compared to repeated encoding in the short‐ and the long‐term. In addition, the effect of repeated testing was beneficial for students irrespectively of working memory capacity. It is argued that teaching methods involving repeated retrieval are important to consider by the educational system.
Influence of Wooden Board Strength Class on the Performance of Cross‐laminated Timber Plates Investigated by Means of Full‐field Deformation Measurements
Authors: Hochreiner G. , Füssl J. , Serrano E. , Eberhardsteiner J. 
Published: December 2013

ABSTRACTAlthough cross‐laminated timber (CLT) plates are increasingly used in high‐performance building structures, a tailored composition of them or, at least, a performance‐based classification scheme is not available. Especially, the influence of the quality of the ‘raw’ material (wooden boards) on the load carrying capacity of CLT elements is hardly investigated yet. For this reason, within this work, bending tests on 24 CLT plates consisting of wooden boards from three different strength classes have been carried out. The global mechanical response as well as the formation of failure mechanisms were investigated, including a full‐field deformation measurement system, which allowed for a qualitatively as well as quantitatively identification of board failure modes. Interestingly, no influence of the board strength class on the elastic limit load of the CLT plates was observed, but the situation was different for the load displacement history beyond the elastic regime, where basically, two different global failure mechanisms could be distinguished. The obtained knowledge about the ‘post‐elastic’ behaviour of CLT plates may serve as a basis for the optimisation of CLT products and the development or improvement of design concepts, respectively. Moreover, the obtained large ‘post‐elastic’ capacity reserve of CLT consisting of high quality boards could lead to a better utilisation of the raw material.
Myometrial physiology – time to translate?
Authors: Arrowsmith Sarah , Kendrick Annabelle , Hanley Jacqui‐Ann , Noble Karen , Wray Susan 
Published: December 2013

New Findings
What is the topic of this review?
To provide an overview of the current understanding of myometrial contractility and give examples of where this has or is close to being applied clinically.
What advances does it highlight?
Examples of where myometrial science has been translated into clinical practice/patient benefit are discussed, as well as including suggestions of how it can be advanced.
In this short review, we discuss how recent insights into myometrial physiology may be taken forward and translated into much‐needed novel therapies for problems associated with labour. We consider excitation–contraction coupling in the myometrium and how this relates to our understanding of the changes that occur to produce myometrial contractions and successful labour. We then discuss how this information has already been used in the development of drugs to either stimulate or relax the myometrium, to address the needs of women with either slow (dystocic) labours or threatened preterm labours, respectively. We next present the data showing how basic physiological findings pertaining to hypoxia and lactate production have been taken and translated into a tool for predicting and thus better managing difficult labours. We then highlight examples of where physiological research has started to provide mechanistic insight into clinical problems associated with labour and parturition (obesity, diabetes, advanced maternal age, postdate and twin pregnancies) and suggest how these findings could be translated into new therapies for difficult labours.
Taguchi Methodology to Optimize the Design of a MR-Brake With Permanent Magnet
Authors: Erol Ozan , Gurocak Hakan 
Published: December 2013

Magnetorheological (MR) brakes provide variable friction torque by electronically changing the viscosity of a magnetic fluid inside the actuator. The MR-brakes have many desirable characteristics, such as high torque-to-volume ratio, inherent stability and ease of control. However, the design process of such an actuator is complex and time consuming due to many parameters involved in the design, including geometric and physical factors and their interactions.
The first contribution of this research is a new optimization approach where we combined the Taguchi optimization method with parameterized magnetic finite element analysis. Unlike other optimization techniques, this method can identify the dominant parameters of the design and investigate their interactions with the design output while reducing the search space and the design time. The second contribution is the design optimization of a novel MR-brake, which incorporates a serpentine flux path and a permanent magnet. To the best of our knowledge, this is the first such MR-brake. The new MR-brake design provides a fail-safe feature while reducing the volume by decreasing the number of coil turns required. Results showed that some of the geometric parameters and the current have the most significant effect on the torque output out of the 12 design parameters.
Numerical Simulation of Well Trajectory While Drilling Isotropic and Anisotropic Formations
Authors: Tikhonov Vadim , Valiullin Khaydar , Ring Lev 
Published: December 2013

In spite of research efforts to develop a numerical model for predicting wellbore trajectory, there isn’t an adequate model for simulating new hole creation and predicting wellbore curvature and build rates that accounts for bottomhole assembly (BHA) dynamics, geometric constraints, rock properties, and steering tool action.
This paper presents new, comprehensive 3D model of BHA dynamics for lateral and torsional modes of motion. This model includes the presence of stabilizers and sections with different geometric and mechanical properties along the BHA. It considers changes in trajectory due to action of bent subs or rotary steerable systems (RSS); allows for abrupt changes to friction factors during transitions from sliding to rolling motions in the wellbore; and accounts for the effects of the bit’s side-milling capacity and side load changes due to changes in the formation.
The DYNTUB software, an advanced simulation tool for predicting well trajectories while drilling, was developed based on this model. This paper presents a mathematical model for the BHA and the well trajectory, the numerical integration method, and the results calculated for various examples steering tools and formations.
Control Strategies for a Linear MR-Brake With Serpentine Flux Path for Haptics
Authors: Alkan Mustafa Sait , Gurocak Hakan 
Published: December 2013

In haptics applications actuators with compact volume and high force output are desired for stable and stiff interfaces. Magnetorheological (MR) brakes are viable options since they have large force-to-volume ratios. However, linear MR-brakes available on the market have limited stroke due to the piston-cylinder design and show viscous damping behavior where the force output highly depends on the velocity of the actuator resulting in a high off-state friction force. Another problem is the inherent magnetic hysteresis, which requires complex control systems.
In this research, we focused on the development and control of a linear MR-brake with infinite stroke and minimal off-state friction. The common piston-cylinder arrangement was removed from the design to address the limited stroke and high off-state-friction issues. The serpentine flux path methodology was followed to achieve compact geometry. Three control strategies namely, open-loop control, force feedback control, and current feedback with Preisach model, were implemented on the developed prototype. The results using Preisach model showed that the hysteresis could be reduced significantly without the need for an expensive force sensor in the control loop.
Our new device has a 3% ratio of the off-state friction force to the maximum force output in comparison to more than 10% for most MR-damper devices in the literature. At the same time, our prototype is about half the size of a commercially available product.
Modeling and Simulation of an Electro-Hydraulic Servovalve in an Intelligent Programming Environment
Authors: Harf Mait , Grossschmidt Gunnar 
Published: December 2013

Composing of models and simulation of statics, steady state conditions and dynamic responses of an electro-hydraulic servovalve is considered in the paper. The observed servovalve contains an electro-mechanical transducer (as a torque motor), a nozzle-and-flapper valve and a sliding spool in sleeve with elastic position feedback from spool to flapper. For composing mathematical models of the servovalve multi-pole models of functional elements are used. For representing relations between inner variables oriented graphs are used.
Results of the current work will be used in modeling and simulation of electro-hydraulic servo-systems.
A Stability Analysis of the Wheel Shimmy
Authors: Di Massa Giandomenico , Pagano Stefano , Strano Salvatore , Terzo Mario 
Published: December 2013

The wheel shimmy is a classical non-linear problem. The most frequently used approach to study this phenomena is based on linearized low degree of freedom models, that from one side, thanks the simplicity of the equations of the motion, allows to evaluate the stability with classical stability-analysis approach, but from the other side it limits the study about the equilibrium point. In this paper a stability-analysis, based on a three degree of freedom non-linear analytical model, is presented. Starting from the system numerical response, adopting a time-domain modal analysis method, the modal parameters were identified.
The proposed procedure, through a 3 degree of freedom nonlinear representation of the castor, highlights the three main castor oscillation modes whose characteristics can then be identified with a method applicable even for experimental investigations.
Path Following Performance of Narrow Tilting Vehicles Equipped With Active Steering
Authors: Robertson James W. , Darling Jos , Plummer Andrew R. 
Published: December 2013

Narrow Tilting Vehicles offer an opportunity to reduce both traffic congestion and carbon emissions by having a small road footprint, low weight, and a small frontal area. Their narrow width requires that they tilt into corners to maintain stability; this may be achieved by means of an automated tilting system. Automated tilt control systems can be classed as Steering Tilt Control (STC) in which active control of the front wheel steer angle is used to maintain stability, Direct Tilt Control (DTC) in which some form of actuator is used to exert a moment between the tilting part(s) of the vehicle and a non-tilting base, or a combination of the two (SDTC). Combined SDTC systems have the potential to offer improved performance as, unlike STC systems, they are effective at low speeds whilst offering superior transient roll stability to DTC systems. However, alterations to the front wheel steer angle made by STC and SDTC systems may result in unwanted deviations from the driver’s intended path.
This paper uses multi-body simulations of a three-wheeled Narrow Tilting Vehicle performing an emergency lane change manoeuvre to show that the path followed by a SDTC equipped vehicle in response to a given series of steer inputs differs significantly from that followed by a DTC equipped vehicle. It is also shown that by using a revised series of steer inputs, a vehicle equipped with SDTC is able to successfully follow a similar path to one equipped with DTC, and that the roll stability of the vehicle is not unduly compromised. Finally, the influence of higher DTC system gains on the SDTC system is considered. It is shown that the result is a small improvement in the vehicle’s path following response at the expense of a small reduction in vehicle roll stability.
Integrating Vehicle Body Concept Modelling and Flexible Multi-Body Techniques for Ride and Handling Simulations
Authors: Carpinelli M. , Mundo D. , Tamarozzi T. , Gubitosa M. , Donders S. , Desmet W. 
Published: December 2013

This paper deals with the integration of a vehicle body concept modeling methodology, based on reduced models of beams, joints and panels, with flexible Multi-body (MB) representation of the chassis of a passenger car. The aim is to enable ride and handling simulations in the initial phases of the vehicle design process, where the availability of predictive Computer Aided Engineering (CAE) tools is a key factor to steer design choices such that a faster convergence of the vehicle development cycle towards improved products is achieved.
The proposed approach is demonstrated on an industrial case study, involving a commercial passenger car, for which a detailed chassis and suspension model for MB simulations is developed in LMS Virtual.Lab Motion. A flexible concept model of the vehicle’s Body In White (BIW) is created as well and included in the MB model to enable fast investigations on how ride and handling performance of the full vehicle are affected by body modifications.
To demonstrate the validity of the resulting concept model, a number of standard handling manoeuvres and ride excitations are simulated by using both the flexible MB model described above and a rigid MB model of the vehicle, which is derived from the same FE model. The numerical results are compared to allow assessing the influence of body flexibility on the predicted handling and ride behaviour of the vehicle.