Absolute Variation Research Articles

Neuromuscular Fatigue after Small-Sided Games in Wheelchair Basketball Players with and without Spinal Cord Injury

ABSTRACT Purpose: The aim was to analyze the differences between wheelchair basketball players with Spinal Cord Injury (SCI) and without Spinal Cord injury (Non-SCI) in psycho-physiological response and neuromuscular fatigue in a series of small-sided games (SSG). Methods: Thirteen high-level wheelchair basketball male players (age 28.8 ± 9.2 years, body mass 75.9 ± 11.3 kg) participated in four versus four SSG once a week for five consecutive weeks. Absolute and relative heart rate (HR) during SSG and muscular and respiratory perceived exertion (RPEmus and RPEres), tympanic temperature, and acceleration capacity were recorded at the end of each SSG. Results: No significant differences were observed between SCI and non-SCI players in relative HR variables in SSG series. However, the SCI group had a lower absolute HR (mean HR and peak HR) (p < .05 or p < .01, ES = 0.73–1.39) and higher perceived muscular load (RPEmusTL) (p < .01, ES = 0.75–0.82) during SSG. Regarding the evolution of the physiological response, no differences were observed between the four bouts in the SCI group. However, the Non-SCI group showed an increase in the absolute and relative variables of HR and RPEres and RPEmus (p < .05 or p < .01, ES = 0.45–1.06). On the contrary, only the SCI group showed a loss of acceleration capacity between the four series (p < .05, ES = 0.28–0.35). Conclusion: The results of this study show that there are differences between SCI and non-SCI wheelchair basketball players in their physiological response and acceleration capacity during SSG tasks.

The Cycle study: a prospective study on cholesterol levels during the menstrual cycle

Abstract Background Previous studies showed fluctuating lipid levels during the menstrual cycle in healthy women with normal cholesterol (nChol). Cycle-related variations in lipid levels in women with familial hypercholesterolemia (FH) have not been studied, while these might have important consequences for lipid management. Purpose To investigate menstrual cycle-related fluctuations in lipid levels in women with FH compared to those with nChol. Methods In the Netherlands and Norway, 20 women with clinical/genetic FH and 63 healthy women with nChol were included - details are presented in the figures. Participants had to have a regular cycle between 21-35 days, while pregnant women, and those using hormone-based contraceptives without hormone free interval (HFI) were excluded. Lipid levels were measured in the follicular (visit 1), ovulation (visit 2), and luteal (visit 3) phases. In women using oral contraceptives (OC) measurements were taken during day 12-14 of the pill period (visit 1) and during day 5-7 of the HFI (visit 2). Results Mean (sd) age of the included subjects was 33 (9) years, BMI 23.9 (4) kg/m2, and cycle duration 28 (2) days. These characteristics were similar in FH and nChol. Women with nChol showed slight, although statistically significant, cycle-related variations in cholesterol levels (mean maximum variation total Chol 0.53, LDL-Chol 0.39 and HDL-Chol 0.22 mmol/L; figure 1). FH women who did not receive statin therapy for various reasons showed largest mean variations (total Chol 0.80, LDL-Chol 0.59 and HDL-Chol 0.23 mmol/L), with the highest lipid levels during the ovulation phase. The women with OC had an increase in total- and LDL-cholesterol (groups combined: mean difference 0.55 and 0.51 mmol/L, respectively) between the two visits (n=9) (figure 2). Conclusions In women with untreated FH and normal cholesterol with a regular menstrual cycle, total- and HDL-cholesterol were highest at ovulation. These menstrual fluctuations were absent in women with FH who used statins. Women with OC showed an increase in total- and LDL-cholesterol from the contraceptive pill period to the HFI. Even though in most women the absolute variation in lipid levels during the menstrual cycle and OC are modest, the moment of measurement can be of clinical value in particular in women with untreated high lipid levels. In these women, it is recommended to measure lipid levels at a fixed time of the menstrual cycle.Figure 1Figure 2

Sliding mode controller design for unstable processes with dead time with a case study on continuous stirred tank reactor

Unstable processes are difficult to control because one or more poles lie on the right-hand side of the s-plane. Control becomes further complicated by the presence of dead time in such systems. In this study, a sliding mode control (SMC) design is proposed for the control of unstable processes with dead time. To apply the SMC, a second order plus dead time (SOPDT) model of the unstable process is used, and a proportional-integral-derivative-acceleration type sliding surface is considered. The parameters of continuous and discontinuous control laws are obtained using the differential evolution optimization technique. The optimal control problem is solved by satisfying a new weighted bi-objective function constituting the performance index integral absolute error and control input total variation. The proposed control scheme has been satisfactorily extended to control unstable integrating and higher-order unstable processes with dead time by approximating them into the unstable SOPDT model. The efficacy of the suggested scheme has been evaluated on several benchmark unstable industrial chemical processes, including the continuous stirred tank reactor (CSTR). Further, this scheme has been compared with recently reported work, and the obtained results clearly demonstrate the effectiveness of the suggested controller.

Preoperative Embolization in Surgical Resection of Cervical Paragangliomas: Usefulness and Current Evidence.

Cervical paragangliomas (CPG) are slow-growing tumours, most of which are highly vascular, making surgical resection challenging. Preoperative embolisation of afferent arteries has been recommended to facilitate operative dissection, reduce perioperative blood loss, and shorten the duration of the operation. However, there is conflicting evidence on the benefits of preoperative embolisation on surgical outcomes, operative time, and bleeding. The objective of this study was to compare the perioperative parameters and outcomes like duration of surgery, blood transfusion, duration of stay in the ICU, cranial nerve injuries, and postoperative stroke between patients who underwent excision of CPGs with and without preoperative embolisation. This is a retrospective study conducted at the Division of Vascular Surgery, Sree Chitra Tirunal Institute of Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. The study included a review of the medical records of 32 patients who underwent excision of CPGs.Patients who underwent surgical resection without preoperative embolisation (SR) were compared with those who underwent surgical resection with embolisation (SREMB). Statistical analysis was done in R statistical software (R Foundation for Statistical Computing, Vienna, Austria). Categorical variables were reported in absolute numbers and percentages continuous variables were compared with an unpaired Mann-Whitney U test. The chi-square test was used to compare the categorical data. Out of 32 patients included in this study, 13 (40.6%) patients were included in the SREMB group. Between the two groups, there were no significant differences in operative time (120 vs. 150 minutes; p = 0.59), blood transfusion requirement (0.69 vs. 0.37 units; p = 0.39) and ICU stays (1 vs. 1; p = 0.56).Postoperative cranial nerve injury was significantly more in the SREMB group (6 vs 1; p = 0.01) but stroke (0 vs 2; p = 0.50) was not statistically significant between the two groups. In this study, we found that there was insufficient evidence to support routine preoperative embolisation in CPG.Hence, preoperative embolisation should only be used in a very select group of patients.

Effect of Repeated Intravitreal Injections in Glaucoma Spectrum Diseases.

To evaluate whether repeated intravitreal injections (IVI) with an anti-vascular endothelial growth factor (anti-VEGF) agent are associated with glaucomatous progression in eyes with glaucoma spectrum diseases (GSD). Single-center, retrospective, longitudinal study of patients with bilateral and similar GSD who: (1) received ≥8 IVI in only one eye during the study period; (2) had ≥2 retinal nerve fiber layer thickness (RNFL) measurements obtained by spectral-domain optical coherence tomography (SD-OCT) at least 12 months apart. The primary outcome was the absolute RNFL thickness change, comparing injected and fellow uninjected eyes. Linear mixed effects models were constructed, including a multivariable model. Sixty-eight eyes from 34 patients were included, 34 injected and 34 fellow uninjected eyes. Average baseline age was 67.68±21.77 years with a follow-up of 3.66±1.89 years and 25.12±14.49 IVI. RNFL thickness decreased significantly from 80.92±15.78 to 77.20±17.35 μm (p<0.001; -1.18±1.93 μm/year) in injected eyes and from 79.95±17.91 to 76.61±17.97 μm (p<0.001; -1.07±0.98 μm/year) in uninjected eyes. In a multivariable linear mixed model of injected eyes, only higher baseline RNFL thickness (p < 0.001) significantly predicted higher absolute RNFL thickness loss. Neither absolute RNFL thickness variation (p=0.716) nor RNFL rate (p=0.779) was significantly different between paired injected and uninjected eyes. Absolute IOP variation was not significantly different between groups (16.62±4.77 to 15.09±4.34 mmHg in injected eyes and 17.68±5.01 to 14.50±3.39 mmHg in fellow uninjected eyes; p=0.248). The proportion of eyes receiving glaucoma medical treatment increased significantly in both groups (55.9% to 76.5% in injected eyes; p=0.039; 58.8% to 76.5% in uninjected eyes; p = 0.031). The number of glaucoma medications also increased significantly in both groups (1.03±1.11 to 1.59±1.18 glaucoma medications in injected eyes; p=0.003; 1.09±1.11 to 1.56±1.19 glaucoma medications in uninjected eyes; p=0.003). Repeated IVI do not seem to accelerate glaucomatous progression. Future studies with a longer follow-up are needed.

Conflicting Associations among Bioelectrical Impedance and Cardiometabolic Health Parameters in Young White and Black Adults.

The purpose of this cross-sectional evaluation was to determine the associations between raw bioelectrical impedance and cardiometabolic health parameters in a sample of young non-Hispanic White and African American adults. A total of 96 (female: 52, male: 44) non-Hispanic White ( n = 45) and African American adults ( n = 51) between the ages of 19 and 37 yr (22.7 ± 3.83 yr) completed several fasted assessments including resting systolic blood pressure (rSBP), blood glucose (FBG), blood lipids, and bioelectrical impedance spectroscopy. Bioelectrical impedance spectroscopy-derived measurements included phase angle, bioimpedance index (BI), impedance ratio (IR), reactance index (XCi), fat-free mass (FFM), FFM index (FFMi), and absolute (a) and relative (%) total body water (TBW) and extracellular (ECF) and intracellular fluid (ICF). All bioelectric variables were collected at 50 kHz other than IR (250 kHz/5 kHz). Multiple regressions were conducted and adjusted for sex, age, and body mass index. rSBP was positively, and HDL was inversely, associated with all bioelectrical impedance and absolute hydration variables (all P ≤ 0.050) other than XCi for rSBP and XCi and FFMi for HDL. rSBP ( P < 0.001) was inversely, and HDL ( P = 0.034) was positively, associated with IR. FBG was positively associated with BI, XCi, FFM, TBWa, and ECFa (all P < 0.050). Metabolic syndrome severity was positively associated with BI, FFM, TBWa, and ECFa for women (all P ≤ 0.050) and with ICFa for African American women ( P = 0.016). Given the rapid increase in the prevalence of cardiometabolic health risks among young adults and the broad use of bioelectrical impedance in practice, the conflicting associations we observed in this age group suggest that bioelectrical impedance parameters should be used with caution in the context of cardiometabolic health risks and age.

A Ratio Between Infrarenal and Suprarenal Aortic Diameters Corrects for Absolute Aortic Diameter Variations due to Patients' Sex and Body Size.

Aortic diameters may differ significantly between patients with different gender and body size. The aim of this study was to relate absolute aortic diameters to age, sex, height, and weight of the patients and to correct for these factors by calculating the ratio between the infrarenal and the suprarenal aortic diameters. A total of 458 patients who underwent elective endovascular aneurysm repair (EVAR) between 2004 and 2018 were included. The aortic anatomy in this group of elective EVAR patients was compared with a control group of 75 patients without an abdominal aortic aneurysm (AAA). The aortic diameter was measured at 4 suprarenal points and 4 infrarenal points. Ratios were calculated by dividing the mean infrarenal neck diameter by 4 suprarenal measurements. Patients in the aneurysm group had significantly larger suprarenal and infrarenal aortic diameters. The ratios between the mean infrarenal neck diameter and all 4 suprarenal measurements were larger in the AAA group than in the control group. In both groups, there was a significant correlation between the mean infrarenal neck diameter and sex, height, weight, and body surface area (BSA). However, in both groups, all 4 ratios between the mean infrarenal neck diameter and suprarenal aortic diameters were not correlated with age, sex, height, weight, or BSA, except for the ratio between the mean infrarenal neck diameter and the aortic diameter measurement proximal to the upper renal artery, which was correlated to weight and BSA in the control group. The mean infrarenal neck diameter is correlated with sex, height, weight, and BSA. However, when the suprarenal aortic diameter was used as an internal control for the mean infrarenal neck diameter, we were able to correct for these variations in aortic diameters due to sex and body size. The clinical relevance of this ratio in patients treated by EVAR has yet to be assessed in future research. In the assessment for EVAR suitability the absolute diameter of the aneurysm neck is taken into account. We believe that using absolute diameters is not the appropriate way to assess this suitability, but that patient characteristics such as age, gender and body size, should be factored into this assessment. In this paper, we show that suprarenal and infrarenal aortic diameters are both significantly increased in patients with an aneurysm compared with patients without an aneurysm. Besides, we found that mean infrarenal aortic diameter is correlated with sex, height, weight, and body surface area. Finally, we propose a new ratio system, using suprarenal diameters as an internal control, to correct for aortic diameter variations due to sex and body size.

Computational Fluid Dynamics Evaluation of an Oil-flooded Screw Compressor

The cost of energy is directly influenced by geopolitical, economic, and environmental factors. There is an international trend towards renewable resources, although the implementation pace and legislation in force have issues. Complete abolishment of fossil fuels is practically impossible. Evolution is only possible with the use of these fuels but with modern, efficient equipment to reduce the pollution resulting from the process of extracting, processing, and using fossil fuels. In this paper, a screw compressor with oil injection, used in oil extraction stations, is analyzed numerically. This analysis is useful in the process of modernizing and improving the efficiency of this type of compressor, which is capable of operating in extreme working regimes, highly contaminated with impurities. The numerical analysis presented certain challenges related to biphasic flow in extremely small spaces at high compression ratios. The results include the absolute pressure variation and the flow rate variation. Regarding future research, test series will be carried out to validate the numerical results on the test bench with a 1:1 scale prototype.

Does broadband affect local economic outcomes less than we thought? Micro evidence from Louisiana

AbstractHigh‐speed internet access is a core tenet of economic development strategies post‐COVID. While expanding access is linked to many positive benefits, evidence associating broadband to job growth and business formation is more mixed. This study expands the literature along several dimensions, most notably exploring how business download speeds affect employment, business formation, and survival at a microscale. Using conventional and Least Absolute Shrinkage and Selection Operator instrumental variables strategies, with terrain features as instruments, we find consistent evidence that broadband speeds stimulate local development. However, our estimates are 60%–65% smaller than those from recent studies, suggesting that broadband may be less beneficial than previously assumed.

OR10-02 Effect Of Phosphodiesterase 4 Inhibitors On Weight Loss And Energy Homeostasis In Mice With Obesity Induced By A High-fat-diet

Abstract Disclosure: M.A. de Andrade: None. H. da Silva: None. A.A. Jesus: None. F.J. de Paula: None. L. Elias: None. INTRODUCTION: Obesity is a worldwide health problem and the incidence of associated diseases such as type 2 diabetes is increasing. Leptin (Lep) resistance arises from obesity-related inflammation, enhancing the appetite. The expression of phosphodiesterase 4 enzymes (PDE4) is increased in inflammatory conditions. Rolipram (Rol) acts to inhibit PDE4 reducing adiposity and peripheral inflammation. Notwithstanding, the effects of Rol on Lep sensitivity and energy balance are still unknown. Objective: To evaluate the effect of PDE4 inhibition on energy homeostasis and Lep sensitivity and glucose tolerance in mice with obesity induced by a high-fat diet (HFD). Methodology: Four-week-old male C57BL6 mice were fed a HFD (60%, Research Diets) or chow diet (C) for 10 weeks. In the 8th week, they received daily subcutaneous Rol injections (2mg/kg) or vehicle (V) and food intake and body weight were daily measured. Energy expenditure (EE) was measured on the 8th day of treatment using a metabolic cage (Oxymax). After treatment, mice underwent 6h fasting and subsequent intraperitoneal (i.p.) glucose injection (2g/kg). Fasting blood glucose (FG) and 120 minutes after glucose (GTT) were measured. On the last day of treatment, 90 minutes after the Rol or V injection, i.p. Lep (5mg/kg in 100ul) or saline (S) was injected, and weight and food intake were measured 14 and 24h later. Results: 5-10 mice were analyzed in each group (chow + V, CV; chow + Rol, CR; HFD + V, HV; HFD + Rol, HR). There was a significant difference in body weight between HR and HV: absolute weight (HR 35+-4.18; HV 38.8+-3.88g; p 0.038) and weight variation (HR -2.26+-0.99; HV -0.19+-1.25g; p 0.002), but no difference between CR and CV (27.98+-2.25; 26.8 +- 2.22g, p 0.97). Rol effectively reduced ingestion in both diets (CR 42.85+-2.7; CV 48.13+-4.51g; p 0.03) (HR 24.75+-2.44; HV 28.31 +-2.81g; p 0.01). In the HFD groups, compared to V, Rol increased VO2 (p 0.04) and energy expenditure (p 0.049) as well as the heat (p 0.03). There was no difference in VCO2 nor motor activity. Lep sensitivity was evaluated in the HFD group and there was a significant reduction in food intake 24h after the Lep application compared to S (Lep 2.18+-0.2; S 2.47+-0.18g, p 0.04). There was no difference in food intake 14h after Lep or weight after injection at either time point (14/24h). Rol was ineffective to improve FG/GTT in the HFD group. Conclusion: Rolipram, a PDE4 inhibitor, effectively reduces the body weight of diet-induced obesity by reducing food intake, increasing basal energy expenditure and improving leptin sensitivity. PDE4 appears as a potential target to treat obesity. Presentation: Friday, June 16, 2023

Investigation on the pressure and flow characteristics for a high-speed bullet in high-altitude flight

The pressure analysis and flow characteristics during the flight of a high-speed bullet are significant for aerodynamic performance, flight trajectory control, safety and reliability, performance optimization, guidance and navigation. To accurately monitor the pressure variation for a high-speed bullet in the high-altitude flight, a novel local fluid domain method is introduced in current study. This method overcomes the limitations of conventional global fluid domain simulation methods, which often suffer from poor convergence and stability issues. On the basis, the force analysis is conducted and the mathematical model for the theoretical trajectory is established, which is applied to simulate the flight trajectory and construct fluid domain for the high-speed bullet. The findings reveal that monitoring points within the bullet hole are influenced by both cavity flow and the collision of forward airflows during the high-altitude flight. Furthermore, it is observed that the absolute total pressure and reference pressure at these monitoring points within the bullet hole are influenced by altitude variations. Subsequently, the factors affecting the absolute total pressure within the hole are explored, including the hole depth, the hole diameter, the hole position, and the bullet orientation. The results indicate that modifying the bullet structure to incorporate 45° angled hole, as opposed to standard holes, can lead to a 13.6% reduction in absolute total pressure variation. Additionally, mitigating the interaction between the external and internal fluids emerges as a critical factor in reducing absolute total pressure within the hole. This research not only presents a fresh perspective for pressure monitoring within the bullet hole, but also establishes a theoretical foundation for the precise guidance of high-altitude bullets.

Signal Variability Comparative Analysis of Healthy Early- and Late-Pubertal Children during Cardiopulmonary Exercise Testing.

The kinetics of physiological responses to exercise have traditionally been characterized by estimating exponential equation parameters using iterative best-fit techniques of heart rate (HR) and gas exchange (respiratory rate, oxygen uptake (V̇O 2 ), carbon dioxide output, and ventilation). In this study, we present a novel approach to characterizing the maturation of physiological responses to exercise in children by accounting for response uncertainty and variability. Thirty-seven early-pubertal (17 females, 20 males) and 44 late-pubertal (25 females, 19 males) participants performed three multiple brief exercise bouts (MBEB). MBEB consisted of ten 2-min bouts of cycle ergometry at constant work rate interspersed by 1-min rest. Exercise intensity was categorized as low, moderate, or high, corresponding to 40%, 60%, and 80% of peak work rate, and performed in random order on 3 separate days. We evaluated sample entropy (SampEn), approximate entropy, detrended fluctuation analysis, and average absolute local variability of HR and gas exchange. SampEn of HR and gas-exchange responses to MBEB was greater in early- compared with late-pubertal participants (e.g., V̇O 2 early-pubertal vs late-pubertal, 1.70 ± 0.023 vs 1.41 ± 0.027; P = 2.97 × 10 -14 ), and decreased as MBEB intensity increased (e.g., 0.37 ± 0.01 HR for low-intensity compared with 0.21 ± 0.014 for high intensity, P = 3.56 × 10 -17 ). Females tended to have higher SampEn than males (e.g., 1.61 ± 0.025 V̇O 2 for females vs 1.46 ± 0.031 for males, P = 1.28 × 10 -4 ). Average absolute local variability was higher in younger participants for both gas exchange and HR (e.g., early-pubertal vs late-pubertal V̇O 2 , 17.48 % ± 0.56% vs 10.24 % ± 0.34%; P = 1.18 × 10 -21 ). The greater entropy in signal response to a known, quantifiable exercise perturbation in the younger children might represent maturation-dependent, enhanced competition among physiological controlling mechanisms that originate at the autonomic, subconscious, and cognitive levels.

Physical fitness, cardiovascular and musculoskeletal health, and occupational performance in firefighters.

To perform their work efficiently and safely, firefighters should maintain all aspects of physical fitness. Cardiac-related incidents are the leading cause of duty-related deaths in firefighters, and many firefighters have poor musculoskeletal health (MSH) that hinder their occupational performance (OP). Establishing the relationship between physical fitness, cardiovascular health (CVH), MSH and OP may add new insight on the most significant factors influencing OP in firefighters, specifically in the City of Cape Town Fire and Rescue Service (CoCTFS), which had not been studied before. Therefore, the purpose of this study was to investigate whether physical fitness, CVH and MSH were associated with OP in firefighters, in the COCTFRS. This cross-sectional study included 283 full-time firefighters aged 20-65 years from Cape Town, South Africa. A researcher-generated questionnaire was used to collect data on sociodemographic characteristics, lifestyle factors and MSH. Physical measures were used to collect information on physical fitness, CVH, and OP [using a physical ability test (PAT)]. Linear and binary logistic regressions, adjusted for age, sex, height and weekly metabolic equivalent minutes (WMETM), multivariate analysis of covariance (MANCOVA), adjusted for age, sex, height and body mass index (BMI) and backward stepwise regressions were used to investigate the associations between the various constructs. From multivariable analyses, age, lean body mass, body fat percentage (BF%), estimated absolute oxygen consumption (abV̇O2max), grip strength, leg strength, push-ups, sit-ups, WMETM and heart rate variability were associated with PAT completion times (all p < 0.01). The MANCOVA showed a significant difference between performance categories of the PAT based on physical fitness and CVH (both p < 0.001). WMETM, BF%, abV̇O2max, grip strength, leg strength and sit-ups explained the highest proportion (50.5%) of the variation in PAT completion times. Younger, non-obese, fitter and stronger firefighters, with a better CVH status, performed significantly better and were most likely to pass the PAT in firefighters, in Cape Town, South Africa. Firefighters should maintain high levels of physical fitness and a good level of CVH to ensure a satisfactory level of OP.

Utilisation of transitional clusters exhibited within soccer game play to inform training design

The aims of this study were to investigate the effect of 15min blocks on physical metrics during transitions, analyse frequency, type, duration, and recovery period between clusters of transitional activities (CTA) in elite football. During ten official matches 23 elite footballers were tracked using GPS devices. Metrics per minute (m·min-1) as well as absolute variables: total distance (TD), high-speed running distance (HSRD &gt; 19.8 km·h-1), sprint distance (SD &gt; 25.2 km·h-1), relative high-speed running distance (VelB4), relative sprint distance (VelB5), acceleration distance (AccB3 Dist, distance with variations in running speed &gt; 3 m·s-2), the number of high-intensity accelerations (HI Acc &gt; 3 m·s-2) and decelerations (HI Dec &gt; 3 m·s-2) were quantified. Significant effects of 15min blocks were found for TD (m) (p &lt; .001; ES = .078), TD (m·min-1) (p = .047; ES = .036), HSRD (m) (p = .033; ES = .039), VelB4 (m) (p &lt; .001; ES = .132), and HI Dec (n·min-1) (p = .002; ES = .059). Transitional activities recovery period was found to be 108.5 ± 26.2 s, CTA recovery period was 25.7 ± 3.6 s, while CTA peak duration reached 53.3 ± 18.2 s. This study indicates that physical metrics decrease in the last 15min blocks during transitions and high-pressure activities in games. In conclusion, repeated high intensity / high velocity activities frequently occur during contextualized peak intensity periods (transitions) in football, which should be reflected in modern training design.

Pressure Drop and Heat Transfer Characteristics of TiO2/R1234yf Nanorefrigerant: A Numerical Approach

Global warming is one of the most dangerous ecological issues facing the globe. Refrigerants are a major contributor to global warming. This investigation mainly focuses on the analysis of a greener nanorefrigerant. Nanorefrigerant can improve the efficiency of refrigeration and air conditioning systems that use vapor compression. In the present investigation, mathematical and computational methods are used to assess the heat transfer and pressure drop properties of TiO2/R1234yf. In order to analyze the heat transfer characteristics and the transport features of the innovative nanorefrigerant, appropriate mathematical predictive models were adapted from earlier investigations. The models are validated by the experiments using TiO2/POE nanolubricant as a test fluid. The investigation was conducted with a temperature range of 10 °C to 40 °C and a volume percentage of nano-sized TiO2 particles in R1234yf refrigerant ranging from 0.2 to 1%. According to the research, the introduction of nanoparticles increases viscosity, thermal conductivity, and density. However, as the amount of nanoparticles rises, the specific heat capacity of the nano-enhanced refrigerant decreases. The nanorefrigerant’s heat transfer coefficient and pressure drop are improved by 134.03% and 80.77%, respectively. The outcomes observed from the predictive technique and the simulation approach had an average absolute variation of 9.91%.

Monitoring absolute vertical land motions and absolute sea-level changes from GPS and tide gauges data over French Polynesia

In this study, we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System (GNSS) receivers over French Polynesia during the period 2007–2020, and obtain, as ancillary results, estimates of the absolute changes in sea level at the same locations. To verify our processing approach to determining vertical motion, we first modeled vertical motion at the International GNSS Service (IGS) THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations, with a good agreement. We obtained the following estimates for the vertical land motions at the tide gauges: Tubuai island, Austral Archipelago −0.92 ± 0.17 mm/yr, Vairao village, Tahiti Iti: −0.49 ± 0.39 mm/yr, Rikitea, Gambier Archipelago −0.43 ± 0.17 mm/yr. The absolute variations of the sea level are: Tubuai island, Austral Archipelago 5.25 ± 0.60 mm/yr, Vairao village, Tahiti Iti: 3.62 ± 0.52 mm/yr, Rikitea, Gambier Archipelago 1.52 ± 0.23 mm/yr. We discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.

Cerebral autoregulation and cerebral blood flow response to mean arterial pressure challenge following induction of general anaesthesia for neuroradiology procedure

IntroductionIntraoperative hypotension is common following general anaesthesia induction with propofol, but its impact on cerebral autoregulation (CA) remains unclear. We investigate the incidence and risk factors of impaired CApost-propofol induction and its recovery after a mean arterial pressure (mAP) challenge.MethodsWe included 40 non-emergency neuroradiology surgery patients [58 (47, 58)years old., 57% women]. We recorded mAP, mean blood flow velocity in the mean cerebral artery (MCAvmean), and regional cerebral oxygen saturation (rSO2). We computed the mean flow index (Mxa) pre and post mAP challenge. Mxa &amp;gt; 0.3 defined poor CA.ResultsAfter anaesthesia induction, 21 (53%) had impaired CBF autoregulation (CA−, Mxa &amp;gt; 0.3). The average mAP was 66 ± 9 mmHg, average MCAv was 39 ± 12 cm.s−1, and rSO2 was 63 ± 7%. We found no significant difference in age, norepinephrine infusion rate, and cardiovascular risks factors were similar between CA− and CA+ (Mxa ≤ 0.3) patients. Among the 22 patients (CA−: n = 14; CA+: n = 8) undergoing mAP challenge, there was a significant Mxa improvement and MCAv increase among CA− patients, (CA−: 0.63 ± 0.18 vs. 0.28 ± 0.20, p &amp;lt; 0.001), and [absolute variation: 1 (0.7–1.5) vs. 7 (3–9) cm.sec−1], respectively.ConclusionAfter induction of general anaesthesia for neuroradiology procedure, 53% of the patients had an impaired CA, regardless of age or medical history. Importantly, a mAP challenge effectively restored CA and improved CBF.Clinical Trial Registrationidentifier, NCT04288869

Patient specific prior cross attention for kV decomposition in paraspinal motion tracking.

X-ray image quality is critical for accurate intrafraction motion tracking in radiation therapy. This study aims to develop a deep-learning algorithm to improve kV image contrast by decomposing the image into bony and soft tissue components. In particular, we designed a priori attention mechanism in the neural network framework for optimal decomposition. We show that a patient-specific prior cross-attention (PCAT) mechanism can boost the performance of kV image decomposition. We demonstrate its use in paraspinal SBRT motion tracking with online kV imaging. Online 2D kV projections were acquired during paraspinal SBRT for patient motion monitoring. The patient-specific prior images were generated by randomly shifting and rotating spine-only DRR created from the setup CBCT, simulating potential motions. The latent features of the prior images were incorporated into the PCAT using multi-head cross attention. The neural network aimed to learn to selectively amplify the transmission of the projection image features that correlate with features of the priori. The PCAT network structure consisted of (1) a dual-branch generator that separates the spine and soft tissue component of the kV projection image and (2) a dual-function discriminator (DFD) that provides the realness score of the predicted images. For supervision, we used a loss combining mean absolute error loss, discriminator loss, perceptual loss, total variation, and mean squared error loss for soft tissues. The proposed PCAT approach was benchmarked against previous work using the ResNet generative adversarial network (ResNetGAN) without prior information. The trained PCAT had improved performance in effectively retaining and preserving the spine structure and texture information while suppressing the soft tissues from the kV projection images. The decomposed spine-only x-ray images had the submillimeter matching accuracy at all beam angles. The decomposed spine-only x-ray significantly reduced the maximum errors to 0.44mm(<2 pixels) in comparison to 0.92mm (∼4 pixels) of ResNetGAN. The PCAT decomposed spine images also had higher PSNR and SSIM (p-value<0.001). The PCAT selectively learned the important latent features by incorporating the patient-specific prior knowledge into the deep learning algorithm, significantly improving the robustness of the kV projection image decomposition, and leading to improved motion tracking accuracy in paraspinal SBRT.

Future variation of land surface temperature in the Yangtze River Basin based on CMIP6 model

ABSTRACT In recent years, past changes in global and regional land surface temperatures (LST) have been well studied, however, future LST changes have been largely ignored owing to data limitations. In this study, three climate variables of CMIP6, namely air temperature (AT), precipitation (Pre), and leaf area index (LAI), were spatially corrected using the Delta downscaling method. On this basis, by combining MODIS LST, elevation, slope and aspect, a random forest (RF) model was built to calculate the LST from 2022 to 2100. The absolute variability (AV) and Mann-Kendall (M-K) tests were used to quantitatively detect interannual and seasonal LST changes in different Shared Socioeconomic Pathways (SSPs) scenarios. The results showed that the AV value increased successively from SSP1-2.6 to SSP2-4.5 and then to SSP5-8.5. Compared with the base period (2003-2021), the increment in interannual, spring, summer and autumn LST during 2022–2100 was mainly between 1 and 2 °C under three scenarios. The interannual and seasonal LST were spatially characterized by significant warming over large areas, and the increasing was the fastest under SSP5-8.5. These results indicate that, in the future, LST will increase further over large areas, especially in winter.

The Relationship between Bodyweight, Maximum and Relative Strength, and Power Variables during Flywheel Inertial Training

The main aim of this study was to examine the relationship between body weight, absolute and relative strength and power variables in a flywheel Romanian deadlift. A secondary aim was to assess the inter-day reliability of a novel power assessment protocol previously used to determine the inertial load that produced the maximum power output in Flywheel Inertia Training. Ten physically active males took part in this study. Participants had some experience with flywheel devices, but all had a minimum of 24 months of traditional resistance training experience. The first testing session consisted of three sets of 10 repetitions with a different inertial load for each set (0.050, 0.075, and 1.00 kg·m2). Each set’s first and second repetitions were used to build momentum and were excluded from data analysis. The order of inertial load used in each trial was standardized for all participants: first, 0.050 kg·m2, second, 0.075 kg·m2, and last, 0.100 kg·m2. The secondary testing session followed the same procedure as the first. No statistically significant (p &lt; 0.05) effect was found between any of the variables in the correlation analysis. There were large positive correlations between the 1 repetition max flywheel Romanian deadlift and peak concentric power, relative strength, and peak concentric and eccentric peak powers. Both body weight and relative strength showed moderate negative correlations with % eccentric overload, whereas moderate positive correlations were observed between 1RM and peak eccentric power. Both concentric power and eccentric power showed excellent reliability, while the reliability for % eccentric overload ranged from poor to excellent depending on the inertial load. In conclusion, this study shows that a protocol to assess the maximum power output has excellent reliability for both ECC and CON power and may be used in future flywheel training. The results also showed that body weight, maximum strength, and relative strength were not largely related to power variables. An individualized approach to flywheel training is required.