bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the mode of heating on cerebral blood flow, non‐invasive intracranial pressure and thermal tolerance in humans
Authors: Gibbons Travis D. , Ainslie Philip N. , Thomas Kate N. , Wilson Luke C. , Akerman Ashley P. , Donnelly Joseph , Campbell Holly A. , Cotter Jim D. 
Published: February 2021

Key points
The human brain is particularly vulnerable to heat stress; this manifests as impaired cognition, orthostatic tolerance, work capacity and eventually, brain death.
The brain's limitation in the heat is often ascribed to inadequate cerebral blood flow (CBF), but elevated intracranial pressure is commonly observed in mammalian models of heat stroke and can on its own cause functional impairment.
The CBF response to incremental heat strain was dependent on the mode of heating, decreasing by 30% when exposed passively to hot, humid air (sauna), while remaining unchanged or increasing with passive hot‐water immersion (spa) and exercising in a hot environment.
Non‐invasive intracranial pressure estimates (nICP) were increased universally by 18% at volitional thermal tolerance across all modes of heat stress, and therefore may play a contributing role in eliciting thermal tolerance.
The sauna, more so than the spa or exercise, poses a greater challenge to the brain under mild to severe heating due to lower blood flow but similarly increased nICP.
AbstractThe human brain is particularly vulnerable to heat stress; this manifests as impaired cognitive function, orthostatic tolerance, work capacity, and eventually, brain death. This vulnerability is often ascribed to inadequate cerebral blood flow (CBF); however, elevated intracranial pressure (ICP) is also observed in mammalian models of heat stroke. We investigated the changes in CBF with incremental heat strain under three fundamentally different modes of heating, and assessed whether heating per se increased ICP. Fourteen fit participants (seven female) were heated to thermal tolerance or 40°C core temperature (Tc; oesophageal) via passive hot‐water immersion (spa), passive hot, humid air exposure (sauna), cycling exercise, and cycling exercise with CO2 inhalation to prevent heat‐induced hypocapnia. CBF was measured with duplex ultrasound at each 0.5°C increment in Tc and ICP was estimated non‐invasively (nICP) from optic nerve sheath diameter at thermal tolerance. At thermal tolerance, CBF was decreased by 30% in the sauna (P < 0.001), but was unchanged in the spa or with exercise (P ≥ 0.140). CBF increased by 17% when end‐tidal was clamped at eupnoeic pressure (P < 0.001). On the contrary, nICP increased universally by 18% with all modes of heating (P < 0.001). The maximum Tc was achieved with passive heating, and preventing hypocapnia during exercise did not improve exercise or thermal tolerance (P ≥ 0.146). Therefore, the regulation of CBF is dramatically different depending on the mode and dose of heating, whereas nICP responses are not. The sauna, more so than the spa or exercise, poses a greater challenge to the brain under equivalent heat strain.
Assessment of Human Reliability Under the Conditions of Uncertainty: SPAR-H Methodology Interpreted in Terms of Interval-Valued Probabilities
Authors: Krymsky Victor G. , Akhmedzhanov Farit M. 
Published: February 2021

Abstract
The well-known standardized plant analysis risk-human reliability (SPAR-H) methodology is widely used for analysis of human reliability in complex technological systems. It allows assessing the human error probability taking into account eight important groups of performance shaping factors. Application of this methodology to practical problems traditionally involves assumptions which are difficult to verify under the conditions of uncertainty. In particular, it introduces only two possible values of the nominal human error probabilities (for diagnosis and for actions) which do not cover the whole spectrum of the tasks within operator's activity. In addition, although the traditional methodology considers the probabilities of human errors as the random variables, it operates only on a single predefined type of distribution for these variables and does not deal with the real situations in which the type of distribution remains uncertain. The paper proposes modification to the classical approach to enable more adequate modeling of real situations with the lack of available information. The authors suggest usage of the interval-valued probability technique and of the expert judgment on the maximum probability density for actual probabilities of human errors. Such methodology allows obtaining generic results that are valid for the entire set of possible distributions (not only for one of them). The modified methodology gives possibility to derive final assessments of human reliability in interval form indicating “the best case” and “the worst case.” A few numerical examples illustrate the main stages of the suggested procedure.
Low Friction Coefficient Nanocomposite CrAlSiN/Gradient-CrAlSiCN Coatings for High Speed/Dry Machining Applications
Authors: Puneet C. , Valleti Krishna , Venu Gopal A. 
Published: February 2021

Abstract
Providing advanced coating solutions for high-speed dry machining applications is gaining importance by the day especially with the increasing employment of difficult-to-machine materials in niche areas. Taking into account the recent demands in developing such coatings, in the present study, a novel low-friction coefficient nanocomposite coating: CrAlSiN/gradient (G)-CrAlSiCN was developed which can be used in high-speed or dry machining applications. Initially, CrAlSiN nanocomposite coating and carbon incorporated CrAlSiN coating were deposited separately using the cylindrical cathodic arc physical vapor deposition (PVD) technique. The as-deposited films were comprehensively analyzed to determine their adhesion strength, phase composition, sliding wear properties (friction coefficient), hardness, and tool life. Preliminary observations revealed that the films did not show evidence of diamond-like carbon (DLC) formation (from Raman analysis). Further, an increase in the carbon content led to a steep decrease in the adhesion strength. This result persuaded a study on developing a novel coating with gradient carbon architecture that would retain the properties of a nanocomposite whilst supporting the nanocomposite underlayer by reducing the coefficient of friction. In comparison with the CrAlSiN nanocomposite coating and a standard DLC coating, the novel gradient carbon coating showed superior tribological properties along with better tool life. This study marks the first such attempt at studying the influence of carbon incorporation to the CrAlSiN nanocomposite coating on improving the overall mechanical and tribological properties of the coating architecture (CrAlSiN/G-CrAlSiCN) for dry machining applications.
Increasing Throughput in Fused Deposition Modeling by Modulating Bed Temperature
Authors: Snapp Kelsey L. , Gongora Aldair E. , Brown Keith A. 
Published: February 2021

Abstract
Additive manufacturing (AM) techniques, such as fused deposition modeling (FDM), are able to fabricate physical components from three-dimensional (3D) digital models through the sequential deposition of material onto a print bed in a layer-by-layer fashion. In FDM and many other AM techniques, it is critical that the part adheres to the bed during printing. After printing, however, excessive bed adhesion can lead to part damage or prevent automated part removal. In this work, we validate a novel testing method that quickly and cheaply evaluates bed adhesion without constraints on part geometry. Using this method, we study the effect of bed temperature on the peak removal force for polylactic acid (PLA) parts printed on bare borosilicate glass and polyimide (PI)-coated beds. In addition to validating conventional wisdom that bed adhesion is maximized between 60 and 70 °C (140 and 158 °F), we observe that cooling the bed below 40 °C (104 °F), as is commonly done to facilitate part removal, has minimal additional benefit. Counterintuitively, we find that heating the bed after printing is often a more efficient process for facile part removal. In addition to introducing a general method for measuring and optimizing bed adhesion via bed temperature modulation, these results can be used to accelerate the production and testing of AM components in printer farms and autonomous research systems.
Adaptive Parameter Estimation With Convergence Analysis for the Prandtl–Ishlinskii Hysteresis Operator
Authors: Xu Rui , Zhou Miaolei , Tan Xiaobo 
Published: February 2021

Abstract
Hysteresis is a nonlinear characteristic ubiquitously exhibited by smart material sensors and actuators, such as piezoelectric actuators and shape memory alloys. The Prandtl–Ishlinskii (PI) operator is widely used to describe hysteresis of smart material systems due to its simple structure and the existence of analytical inverse. A PI operator consists of a weighted superposition of play (backlash) operators. While adaptive estimation of the weights for PI operators has been reported in the literature, rigorous analysis of parameter convergence is lacking. In this article, we establish persistent excitation and thus parameter convergence for adaptive weight estimation under a rather modest condition on the input to the PI operator. The analysis is further supported via simulation, where a recursive least square (RLS) method is adopted for parameter estimation.
Characterization and Synthesis of Duty Cycles for Battery Energy Storage Used in Peak Shaving Dispatch
Authors: Moy Kevin , Lee Seong Beom , Onori Simona 
Published: February 2021

Abstract
Energy storage systems (ESSs), such as lithium-ion batteries, are being used today in renewable grid systems to provide the capacity, power, and quick response required for operation in grid applications, including peak shaving, frequency regulation, back-up power, and voltage support. Each application imposes a different duty cycle on the ESS. This represents the charge/discharge profile associated with energy generation and demand. Different duty cycle characteristics can have different effects on the performance, life, and duration of ESSs. Within lithium-ion batteries, various chemistries exist that own different features in terms of specific energy, power, and cycle life, that ultimately determine their usability and performance. Therefore, the characterization of duty cycles is a key to determine how to properly design lithium-ion battery systems for grid applications. Given the usage-dependent degradation trajectories, this research task is a critical step to study the unique aging behaviors of grid batteries. Significant energy and cost savings can be achieved by the optimal application of lithium-ion batteries for grid-energy storage, enabling greater utilization of renewable grid systems. In this paper, we propose an approach, based on unsupervised learning and frequency domain techniques, to characterize duty cycles for the grid-specific peak shaving applications. Finally, we propose synthetic duty cycles to mimic grid-battery dynamic behaviors for use in laboratory testing.
The Low-Temperature Adsorption Characteristics of Activated Carbon With 3He and 4He as Sorption Cooler Cryogens
Authors: Xi Xiaotong , Yang Biao , Wang Jue , Chen Liubiao , Wang Junjie 
Published: February 2021

Abstract
As a commonly used sub-Kelvin refrigeration technology, helium sorption coolers play an important role in space and ground applications. The adsorption characteristics of the porous material inside the sorption cooler at low temperature have a crucial influence on its performance. At present, the analysis and calculation of sorption coolers are mainly based on helium 4 (4He) as the working gas, and there is a lack of systematic research on the low-temperature adsorption characteristics of helium-3 (3He) and its coupling effect characteristics of temperature, pressure, and mass distribution in different components. In this paper, a molecular model of activated carbon that is similar to the actual structure was constructed, and the adsorption isobars and isosteric heat of 3He and 4He at 0.8–5 K were comparatively studied based on the grand canonical Monte Carlo (GCMC) method. Besides, the influence of adsorption characteristics of 3He and 4He on the condensation efficiency, the mass distribution after condensation equilibrium, and the self-cooling loss of the sorption cooler were analyzed. The results show that for the 3He sorption cooler, the main factor affecting the condensation efficiency is the adsorbed helium in the sorption pump, while for the 4He sorption cooler, it is the adsorbed helium and the gas in the dead volume. For both 3He and 4He sorption coolers, the condensation efficiency increases as the sorption pump temperature increases or the heat sink temperature decreases, while the self-cooling loss decreases as the heat sink temperature decreases or the operating temperature increases.
Methodologies for Predicting the Effectiveness of Full-Scale Fixed-Bed Regenerators From Small-Scale Test Data
Authors: Krishnan Easwaran N. , Ramin Hadi , Gurubalan A. , Alabi Wahab O. , Simonson Carey J. 
Published: February 2021

Abstract
Fixed-bed regenerators (FBRs) are air-to-air energy exchangers (AAEEs) used to reduce energy consumption in heating, ventilation, and air conditioning (HVAC) systems. Since energy savings are directly related to the effectiveness of FBRs, testing is essential to determine the effectiveness of FBRs for quality assurances and during product development. However, testing of full-scale FBRs has disadvantages such as requiring full-scale prototypes, a high volume of conditioned airflow, long tests, and large testing laboratories. The disadvantages are especially crucial during product development and can be overcome by small-scale testing provided the test data can be used to evaluate accurately full-scale FBRs. The major contribution of this paper is two new methodologies (one direct method and one predictive method) to determine the sensible effectiveness of full-scale FBRs from small-scale test data. In the direct method, the effectiveness of the full-scale FBR is determined directly from the small-scale test data, whereas in the predictive method the effectiveness is determined using the Wilson plot technique and a numerical model in addition to the small-scale test data. Both methods are shown to have uncertainties within the specified uncertainty limits required by testing standards and are applied to evaluate the influence of geometrical parameters (corrugation angle and corrugation depth) on the effectiveness of FBRs. The test methods and results will be useful in the design and development of FBRs for HVAC applications.
Heat Transfer and Second Law Analysis of Ethylene Glycol-Based Ternary Hybrid Nanofluid Under Laminar Flow
Authors: Sundar L. Syam , Chandra Mouli Kotturu V.V. , Said Zafar , Sousa Antonio C. M. 
Published: February 2021

Abstract
Experiments were conducted to evaluate the thermal entropy generation, frictional entropy generation, and exergy efficiency of reduced graphene oxide (rGO)–Fe3O4–TiO2 hybrid nanofluid flow in a circular tube under laminar flow. The ternary nanoparticles were synthesized using the sol–gel technique and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). The stable ethylene glycol-based ternary hybrid nanofluid was prepared and its thermophysical properties, heat transfer, friction factor, and pumping power at various values of particle weight concentrations (0.05–0.2%) and Reynolds number (211–2200) were studied experimentally. Nusselt number, heat transfer coefficient, friction factor, and exergy efficiency augment with increasing values of particle loading and Reynolds number. Results show the thermal conductivity and viscosity increase, as compared to the base fluid, by 10.6% and 108.3% at ψ = 0.2% and 60 °C. Similarly, for ψ = 0.2% and Reynolds number of 1548, and in comparison to the base fluid data, the Nusselt number and heat transfer coefficient enhancement are 17.78% and 24.76%, respectively, the thermal entropy generation reduction is 19.85%, and the exergy efficiency enhancement is 6.23%. At Reynolds number of 221.1, the rise in pressure drop, pumping power, and friction factor is 13.65%, 11.33%, and 16%, respectively, for ψ = 0.2% as compared to the base fluid data. The overall thermal performance of the system is enhanced by 14.32%. New equations are developed for the evaluation of the thermophysical properties, Nusselt number, and friction factor.
Exercise Plus Presleep Protein Ingestion Increases Overnight Muscle Connective Tissue Protein Synthesis Rates in Healthy Older Men
Authors: Holwerda Andrew M. , Trommelen Jorn , Kouw Imre W.K. , Senden Joan M. , Goessens Joy P.B. , van Kranenburg Janneau , Gijsen Annemie P. , Verdijk Lex B. , van Loon Luc J.C. 
Published: February 2021

Protein ingestion and exercise stimulate myofibrillar protein synthesis rates. When combined, exercise further increases the postprandial rise in myofibrillar protein synthesis rates. It remains unclear whether protein ingestion with or without exercise also stimulates muscle connective tissue protein synthesis rates. The authors assessed the impact of presleep protein ingestion on overnight muscle connective tissue protein synthesis rates at rest and during recovery from resistance-type exercise in older men. Thirty-six healthy, older men were randomly assigned to ingest 40 g intrinsically L-[1-13C]-phenylalanine and L-[1-13C]-leucine-labeled casein protein (PRO, n = 12) or a nonprotein placebo (PLA, n = 12) before going to sleep. A third group performed a single bout of resistance-type exercise in the evening before ingesting 40 g intrinsically-labeled casein protein prior to sleep (EX+PRO, n = 12). Continuous intravenous infusions of L-[ring-2H5]-phenylalanine and L-[1-13C]-leucine were applied with blood and muscle tissue samples collected throughout overnight sleep. Presleep protein ingestion did not increase muscle connective tissue protein synthesis rates (0.049 ± 0.013 vs. 0.060 ± 0.024%/hr in PLA and PRO, respectively; p = .73). Exercise plus protein ingestion resulted in greater overnight muscle connective tissue protein synthesis rates (0.095 ± 0.022%/hr) when compared with PLA and PRO (p < .01). Exercise increased the incorporation of dietary protein-derived amino acids into muscle connective tissue protein (0.036 ± 0.013 vs. 0.054 ± 0.009 mole percent excess in PRO vs. EX+PRO, respectively; p < .01). In conclusion, resistance-type exercise plus presleep protein ingestion increases overnight muscle connective tissue protein synthesis rates in older men. Exercise enhances the utilization of dietary protein-derived amino acids as precursors for de novo muscle connective tissue protein synthesis during overnight sleep.
Impaired exocrine pancreatic function in different stages of type 1 diabetes
Authors: Dozio Nicoletta , Indirli Rita , Giamporcaro Gian Maria , Frosio Laura , Mandelli Alessandra , Laurenzi Andrea , Bolla Andrea Mario , Stabilini Angela , Valle Andrea , Locatelli Massimo , Cavestro Giulia Martina , Scavini Marina , Battaglia Manuela , Bosi Emanuele 
Published: February 2021

IntroductionAim of this study was to investigate the pancreatic exocrine function in patients with type 1 diabetes (T1D) by multiple non-invasive tests.Research design and methodsThe study is a single-center, cross-sectional study of pancreatic exocrine function in adult patients with new-onset or long-standing T1D and healthy controls.ResultsHealthy controls, new-onset T1D, and long-standing T1D were similar for age at the time of the study, gender and body mass index (BMI) categories. Age of onset of T1D patients with long-standing disease was younger than that of patients with new-onset T1D (p<0.001). As expected, the three groups differed for C-peptide and hemoglobin A1c (HbA1c) levels. Lipase activity measured by13C-mixed triglyceride breath test was reduced progressively, although not significantly, from controls to recent-onset T1D and long-standing T1D participants. Fecal elastase-1 was significantly lower in participants with T1D, either new onset or long standing. Pancreatic amylase, lipase, retinol binding protein and prealbumin were significantly different across the groups, with a significant trend toward lower values in long-standing T1D and intermediate values in new-onset T1D, while no differences were observed for total amylase. The markers of impaired exocrine function tests (fecal elastase-1, serum pancreatic amylase and lipase) and of nutritional status (retinol binding protein and prealbumin levels) correlated with the reduction of fasting and urinary C-peptide.ConclusionsOur results confirm that exocrine pancreatic impairment is a feature of T1D, with low fecal elastase-1, serum pancreatic amylase and lipase as specific markers, associated with reduced levels of nutritional indexes. Moreover, the evidence of more advanced insufficiency in long-standing disease reflects the chronic nature of this process, and its correlation with the residual β-cell function suggests parallel pathways for the impairment of the endocrine and exocrine pancreatic function.
When does proton pump inhibitor treatment become long term? A scoping review
Authors: Haastrup Peter Fentz , Jarbøl Dorte Ejg , Thompson Wade , Hansen Jane Møller , Søndergaard Jens , Rasmussen Sanne 
Published: February 2021

ObjectiveProton pump inhibitor (PPI) use has risen substantially, primarily driven by ongoing use over months to years. However, there is no consensus on how to define long-term PPI use. Our objectives were to review and compare definitions of long-term PPI use in existing literature and describe the rationale for each definition. Moreover, we aimed to suggest generally applicable definitions for research and clinical use.DesignThe databases PubMed and Cochrane Library were searched for publications concerning long-term use of PPIs and ClinicalTrials.gov was searched for registered studies. Two reviewers independently screened the titles, abstracts, and full texts in two series and subsequently extracted data.ResultsA total of 742 studies were identified, and 59 met the eligibility criteria. In addition, two ongoing studies were identified. The definition of long-term PPI use varied from >2 weeks to >7 years. The most common definition was ≥1 year or ≥6 months. A total of 12/61 (20%) of the studies rationalised their definition.ConclusionThe definitions of long-term PPI treatment varied substantially between studies and were seldom rationalised.In a clinical context, use of PPI for more than 8 weeks could be a reasonable definition of long-term use in patients with reflux symptoms and more than 4 weeks in patients with dyspepsia or peptic ulcer. For research purposes, 6 months could be a possible definition in pharmacoepidemiological studies, whereas studies of adverse effects may require a tailored definition depending on the necessary exposure time. We recommend to always rationalise the choice of definition.