Fitness Tolerance Research Articles

Multi-objective optimization of a triple-eccentric butterfly valve considering structural safety and sealing performance

The structural safety and sealing performance of a triple-eccentric butterfly valve are crucial technical indicators that influence its reliability and service life. In this study, a new multi-objective optimization strategy is proposed to realize a lightweight design of valve trims, reduce the maximum equivalent stress, and reasonably distribute the sealing-specific pressure. A two-stage optimization scheme is designed by combining topology optimization (TO) and response surface methodology optimization (RSM). The topology optimization is employed to allocate the material distribution of the valve trims and provide the parameters for the response surface optimization, while the response surface methodology optimization conducts a further revision and optimization of the structural parameters of the valve trims. The results of the simulation experiments indicate that the maximum equivalent stress of the lightweight designed valve trims is reduced from 290.85 MPa to 99.88 MPa, and the maximum sealing-specific pressure of the sealing surface is reduced from 197.78 MPa to 77.83 MPa. Additionally, a novel approach is presented for assessing the sealing performance using the clearance of the fitting surface. This method can intuitively evaluate the state of metal sealing and guide the design of the fitting tolerance by analyzing the sensitivity of the dimensional deviation to the sealing-specific pressure. The findings demonstrate that the optimized valve exhibits good structural safety and sealing performance.

A review on endophytic bacteria of orchids: functional roles toward synthesis of bioactive metabolites for plant growth promotion and disease biocontrol.

In this review, we have discussed the untapped potential of orchid endophytic bacteria as a valuable reservoir of bioactive metabolites, offering significant contributions to plant growth promotion and disease protection in the context of sustainable agriculture. Orchidaceae is one of the broadest and most diverse flowering plant families on Earth. Although the relationship between orchids and fungi is well documented, bacterial endophytes have recently gained attention for their roles in host development, vigor, and as sources of novel bioactive compounds. These endophytes establish mutualistic relationships with orchids, influencing plant growth, mineral solubilization, nitrogen fixation, and protection from environmental stress and phytopathogens. Current research on orchid-associated bacterial endophytes is limited, presenting significant opportunities to discover new species or genetic variants that improve host fitness and stress tolerance. The potential for extracting bioactive compounds from these bacteria is considerable, and optimization strategies for their sustainable production could significantly enhance their commercial utility. This review discusses the methods used in isolating and identifying endophytic bacteria from orchids, their diversity and significance in promoting orchid growth, and the production of bioactive compounds, with an emphasis on their potential applications in sustainable agriculture and other sectors.

Enhancing arbuscular mycorrhiza symbiosis effectiveness through the involvement of the tomato GRAS transcription factor SCL3/SlGRAS18

Arbuscular mycorrhizal (AM) fungi improve plant growth, nutrition, fitness and stress tolerance while AM fungi obtain carbohydrates and lipids from the host. This whole process of mutual benefit requires substantial alterations in the structural and functional aspects of the host root cells. These modifications ultimately culminate in the formation of arbuscules, which are specialized intraradical and highly branched fungal structures. Arbuscule-containing cells undergo massive reprogramming to hosting arbuscule and members of the GRAS transcription factor family have been characterized as AM inducible genes which play a pivotal role in these process. Here, we show a functional analysis for the GRAS transcription factor SCL3/SlGRAS18 in tomato. SlGRAS18 interacts with SlDELLA, a central regulator of AM formation. Silencing of SlGRAS18 positively impacts arbuscule development and the improvement in symbiotic status, favouring flowering and therefore progress in the formation and development of fruits in SlGRAS18 silenced plants which parallel to a discernible pattern of mineral nutrient redistribution in leaves. Our results advance the knowledge of GRAS transcription factors involved in the formation and establishment of AM symbiosis and provide experimental evidence for how specific genetic alterations can lead to more effective AM symbiosis.

Growth fitness, virulence, and heat tolerance of Salmonella Typhimurium variants resistant to food preservation methods

To study potential ramifications of antimicrobial resistance, we carried out adaptive laboratory evolution assays (ALE) to isolate three resistant variants (RVs) of Salmonella enterica Typhimurium, employing three different types of food preservation methods: 1) an emergent technology, plasma-activated water (PAW), leading to variant RV-PAW; a traditional method, heat, leading to variant RV-HT, and a natural antimicrobial compound, carvacrol, leading to variant RV-CAR. The variant resistant to plasma-activated water, RV-PAW, had mutations in rpoA and rpoD; it showed increased tolerance to heat in orange juice but ultimately did not pose a significant threat, as it exhibited a fitness cost at refrigeration temperature (8 °C), whereas its virulence against Caenorhabditis elegans decreased. The variant resistant to heat, RV-HT, had mutations in flhC, dnaJ: it exhibited a fitness cost at high growth temperatures (43 °C) and induced morphofunctional alterations in C. elegans. The variant resistant to carvacrol, RV-CAR, had mutations in sseG, flhA, wbaV, lon; this variant not only exhibited significantly higher thermotolerance in both laboratory media and food models but also effectively increased its growth fitness at refrigeration temperatures while retaining its virulence, evidenced by the highest percentage of Smurf phenotype in C. elegans.To address these challenges, we applied a process combining thermal treatment with citral, with the aim of leveraging the sublethal damage caused in RVs by heat treatments in orange juice. This approach achieves enhanced microbial inactivation without having to escalate the intensity of the thermal treatment. The result was particularly encouraging in the case of RV-CAR, the most challenging strain, for which we improved lethality by up to 3 log10 inactivation cycles.

EFFECTS OF CARDIAC REHABILITATION IN PATIENTS WITH VENTRICULAR ASSIST DEVICES: A SCOPING REVIEW

Introduction Ventricular assist devices represent a treatment option for patients with advanced heart failure, offering control over various haemodynamic variables. Similarly, the prescription of exercise within a cardiac rehabilitation programme for heart failure patients is recommended to reduce symptoms, hospitalisations, improve cardiorespiratory fitness, and increase exercise tolerance. Therefore, exercise prescription can impact those with ventricular assist devices. Given the limited evidence on exercise-based cardiac rehabilitation programmes for this population, this review aims to describe the most commonly used strategies and their health benefits when physical exercise is included in a cardiac rehabilitation programme for patients with ventricular assist devices. Materials and Methods An exploratory review was conducted through searches in the databases: PubMed, SCOPUS, PeDro, and ScienceDirect. The search was limited to studies published between 2013 and 2023. Filters were applied independently by title, abstract, and full text. The included articles were analysed based on the description of the types of cardiac rehabilitation strategies used in patients with ventricular assist devices. Results Seven articles were included. Each programme employed a cardiopulmonary exercise test before prescribing physical exercise. The most commonly used strategy was aerobic exercise, predominantly high-intensity interval training (HIIT) with intensities close to 90% of peak VO2, followed by continuous moderate-intensity exercise. Limb strength exercises were included in three programmes. Conclusions The analysed literature suggests that cardiac rehabilitation in patients with ventricular assist devices is safe and can provide benefits in cardiorespiratory fitness and exercise tolerance. High-intensity interval training is identified as an appropriate strategy for achieving results, offering short-term improvements.

Multigenerational Effect of Heat Stress on the Drosophila melanogaster Sperm Proteome.

The effect of the parental environment on offspring through non-DNA sequence-based mechanisms, such as DNA methylation, chromatin modifications, noncoding RNAs, and proteins, could only be established after the conception of "epigenetics". These effects are now broadly referred to as multigenerational epigenetic effects. Despite accumulating evidence of male gamete-mediated multigenerational epigenetic inheritance, little is known about the factors that underlie heat stress-induced multigenerational epigenetic inheritance via the male germline in Drosophila. In this study, we address this gap by utilizing an established heat stress paradigm in Drosophila and investigating its multigenerational effect on the sperm proteome. Our findings indicate that multigenerational heat stress during the early embryonic stage significantly influences proteins in the sperm associated with translation, chromatin organization, microtubule-based processes, and the generation of metabolites and energy. Assessment of life-history traits revealed that reproductive fitness and stress tolerance remained unaffected by multigenerational heat stress. Our study offers initial insights into the chromatin-based epigenetic mechanisms as a plausible means of transmitting heat stress memory through the male germline in Drosophila. Furthermore, it sheds light on the repercussions of early embryonic heat stress on male reproductive potential. The data sets from this study are available at the ProteomeXchange Consortium under the identifier PXD037488.

Six-Minute Walk Test among obese and nonobese subjects: A comparative analysis among apparently healthy volunteers

Abstract Context: The Six-Minute Walk Test (6MWT) is a simple measure for objective assessment of physical fitness and exercise tolerance. It has also been standardized to follow up on the prognosis and progression of chronic cardiovascular and respiratory diseases. Though there are standardized formulas for analyzing the 6MWT results concerning age, height, weight, regional, and ethnic population these should be revisited considering the wider variations of subjects in the reference studies. Aim: This article aims to compare the 6MWT performance among obese and nonobese, apparently healthy volunteers. Settings and Design: A cross-sectional study was conducted in the Physiology Department, AIIMS Kalyani, West Bengal, India. Materials and Methods: Age and sex-matched apparently healthy volunteers were included in the study after their consent. After collection of anthropometric data, they were divided into two groups; group A with body mass index (BMI) <30 kg/m2 and group B with BMI >30 kg/m2. The 6MWT was implemented according to standard guidelines; the Six-Minute Walk Distance (6MWD) and other parameters were noted. Statistical analysis was performed by Statistical Package for the Social Sciences software version 17 (IBM Corp., Chicago, IL, USA). Results: The results revealed that a comparison was done between actual values and predicted values of 6MWD. Among obese groups, the actual 6MWD covered was significantly lesser than the predicted values. Significant differences were also found between the two groups concerning Borg score, Calculated volume of oxygen max, systolic and diastolic blood pressures, respiratory rate, heart rate, and Peripheral capillary oxygen saturation. Conclusions: The results revealed that our result shows that the weight-based reference equation for interpretation of 6MWT may not be sufficient for obese subjects.

Semi-supervised exercise training program more effective for individuals with postural orthostatic tachycardia syndrome in randomized controlled trial

PurposeExercise like any medication requires the correct dose; to be effective the appropriate frequency, duration, and intensity are necessary. This study aimed to assess if a semi-supervised exercise training (ET) program would be more effective at improving aerobic fitness (VO2PEAK), exercise tolerance, and symptoms in individuals with postural orthostatic tachycardia syndrome (POTS) compared to the standard of care (SOC).MethodsSubjects were randomized to either the ET or SOC groups (n 26 vs. 23; age 33 ± 11 vs. 37 ± 10 years; VO2PEAK 66 ± 15 vs. 62 ± 15% predicted, ET vs. SOC respectively, p > 0.05). Composite Autonomic Symptom Score (COMPASS 31), 10 min stand test, and cardiopulmonary exercise test were performed at baseline and following 12 weeks. The ET group received an exercise consultation and eight semi-supervised in-person or virtual exercise sessions.ResultsThe ET group demonstrated a greater improvement in VO2PEAK, higher or longer tolerance for baseline peak workload, and more often had a delayed symptom onset with exercise than the SOC group (ΔVO2PEAK 3.4 vs. − 0.2 mL/min/kg, p < 0.0001, ΔWorkload 19 ± 17 vs. 0 ± 10 W; Workload time 63 ± 29 vs. 22 ± 30 s; onset-delay 80% vs. 30%, p < 0.05). Individuals in the ET group reported a significant improvement in orthostatic intolerance domain score (p = 0.02), but there was not a significant difference in the improvement in total COMPASS score (− 11.38 vs. − 6.49, p = 0.09).ConclusionExercise training was more effective with greater improvements in aerobic fitness, orthostatic symptoms, and exercise tolerance for individuals with POTS when intensity and progression were personalized and delivered with minimal supervision compared to the SOC.

Effects of rope skipping exercise on physical, cardiovascular fitness and exercise tolerance in adolescent students with moderate intellectual disability.

Adolescents with intellectual disabilities (ID) who live a sedentary lifestyle may lead to an increased risk of chronic cardiovascular disease in adulthood. The aim of this study is to investigate the effects of 8-week progressive rope skipping training on physical, cardiovascular fitness and exercise tolerance of high school students with moderate ID. Thirty-four senior high school with ID (aged 15-18years old) were randomised into experimental group received progressive skipping rope exercise (RS, n=17) and control group no rope skipping exercise intervention group (CON, n=17). The RS group were received progressive rope skipping exercise for 50min each time, three times a week, for 8weeks. The control group was not allowed to participate in intervention activities during the study period. The physical fitness, body composition, arterial stiffness index (ASI) and blood pressure were measured before and after the 8-week intervention. After the 8-week progressive skipping rope exercise intervention, the participants from the RS group increased in the 3-min step test, sit-up test, grip strength and sit and reach test, when compared to the baseline (P<0.05). The RS group exhibited lower the area under curve of heart rate (HR) during post-exercise recovery (P<0.05). The participants in the RS group showed significant decreases in systolic (SBP) and diastolic (DBP) blood pressure, mean arterial pressure (MAP) and HR when compared to the baseline (P<0.05). Change SBP has moderate positive correlation with change ASI. The results of this experiment suggest that progressive rope skipping exercise might improve physical fitness and promote cardiovascular health, as well as enhance exercise tolerance for adolescent students with moderate ID.

Comparative experimental evolution reveals species-specific idiosyncrasies in marine phytoplankton adaptation to warming.

A number of experimental studies have demonstrated that phytoplankton can display rapid thermal adaptation in response to warmed environments. While these studies provide insight into the evolutionary responses of single species, they tend to employ different experimental techniques. Consequently, our ability to compare the potential for thermal adaptation across different, ecologically relevant, species remains limited. Here, we address this limitation by conducting simultaneous long-term warming experiments with the same experimental design on clonal isolates of three phylogenetically diverse species of marine phytoplankton; the cyanobacterium Synechococcus sp., the prasinophyte Ostreococcus tauri and the diatom Phaeodoactylum tricornutum. Over the same experimental time period, we observed differing levels of thermal adaptation in response to stressful supra-optimal temperatures. Synechococcus sp. displayed the greatest improvement in fitness (i.e., growth rate) and thermal tolerance (i.e., temperature limits of growth). Ostreococcus tauri was able to improve fitness and thermal tolerance, but to a lesser extent. Finally, Phaeodoactylum tricornutum showed no signs of adaptation. These findings could help us understand how the structure of phytoplankton communities may change in response to warming, and possible biogeochemical implications, as some species show relatively more rapid adaptive shifts in their thermal tolerance.

Inbreeding-Driven Innate Behavioral Changes in Drosophila melanogaster.

Drosophila melanogaster has long been used to demonstrate the effect of inbreeding, particularly in relation to reproductive fitness and stress tolerance. In comparison, less attention has been given to exploring the influence of inbreeding on the innate behavior of D. melanogaster. In this study, multiple replicates of six different types of crosses were set in pair conformation of the laboratory-maintained wild-type D. melanogaster. This resulted in progeny with six different levels of inbreeding coefficients. Larvae and adult flies of varied inbreeding coefficients were subjected to different behavioral assays. In addition to the expected inbreeding depression in the-egg to-adult viability, noticeable aberrations were observed in the crawling and phototaxis behaviors of larvae. Negative geotactic behavior as well as positive phototactic behavior of the flies were also found to be adversely affected with increasing levels of inbreeding. Interestingly, positively phototactic inbred flies demonstrated improved learning compared to outbred flies, potentially the consequence of purging. Flies with higher levels of inbreeding exhibited a delay in the manifestation of aggression and courtship. In summary, our findings demonstrate that inbreeding influences the innate behaviors in D. melanogaster, which in turn may affect the overall biological fitness of the flies.

Relationship between Maximum Oxygen Consumption and Lactate Metabolism with Situational Efficiency of Highly Selected Young Judoists

Judo is often referred to as an explosive sport, which requires great anaerobic strength and capacity, with a well-developed aerobic system. Attaining a high level of physical fitness, strength, and fatigue tolerance is essential for achieving success in competition. Fatigue leads to decreased muscle strength, prolonged reaction time, reduced agility, neuromuscular coordination, overall body speed, concentration, and agility. The intensity at which this phenomenon occurs is known as the lactate threshold. The primary objective of the planned research was to establish a link between maximal oxygen consumption (VO2max), lactate metabolism, and the situational efficiency of selected young judoists. The sample consisted of 30 cadet and junior judo athletes from the national teams of Serbia (average age of 16.43±0.76 years, body height of 176.94±5.15 cm, and body weight of 69.71±10.64 kg). The research employed precisely standardized protocols and modern equipment to determine anthropometric characteristics, and the values of maximal oxygen consumption, lactate thresholds, and the index of a specific judo fitness test among the selected young judo athletes. Based on the obtained results, there was a moderate negative correlation between VO2max and the index of the special judo fitness test, as well as a low correlation between the first lactate threshold (PLAP) and the second lactate threshold (DLAP) with the index of the special judo fitness test (ISJFT). Additionally, a moderate negative correlation was found between VO2max and anthropometric parameters, while PLAP and DLAP exhibited low correlations with anthropometric parameters. The research results quantitatively illustrate the physiological adaptation of the top young judo athletes to the physical demands encountered during years of specific training. The proposed battery of tests can be utilized to assess the functional status of competitors more accurately and determine the competition profile for elite judo athletes.

Calculation of Fit Tolerance with Clearance to Increase Relative Wear Resistance of Joints

Calculation of Fit Tolerance with Clearance to Increase Relative Wear Resistance of Joints

Design of Lung Transplant Go (LTGO): A randomized controlled trial evaluating the efficacy of a telerehabilitation behavioral exercise intervention to improve physical activity, physical function, and blood pressure control after lung transplantation

BackgroundLung transplantation is an established treatment option for persons with advanced lung disease. After transplantation, lung function typically returns to near normal levels, however exercise capacity remains low due to chronic deconditioning, limited physical function, and inactive lifestyles which undermine the intended benefits of the highly selective, resource-intensive transplant procedure. Pulmonary rehabilitation is recommended to improve fitness and activity tolerance, however due to multiple barriers, lung transplant recipients either never participate, or fail to complete, pulmonary rehabilitation programs. PurposeTo describe the design of Lung Transplant Go (LTGO), a trial modified for the remote environment based on recommendations to preserve trial integrity during COVID. The aims are to evaluate a behavioral exercise intervention to improve physical function, physical activity, and blood pressure control in lung transplant recipients conducted safely and effectively using a telerehabilitation (telerehab) platform, and to explore the role of potential mediators and moderators of the relationship between LTGO and outcomes. MethodsSingle-site, 2-group randomized controlled trial with lung transplant recipients randomized 1:1 to either the LTGO intervention (a 2-phased, supervised, telerehab behavioral exercise program), or to enhanced usual care (activity tracking and monthly newsletters). All study activities, including intervention delivery, recruitment, consenting, assessment, and data collection, will be performed remotely. ConclusionIf efficacious, this fully scalable and replicable telerehab intervention could be efficiently translated to reach large numbers of lung recipients to improve and sustain self-management of exercise habits by overcoming barriers to participation in existing, in-person pulmonary rehabilitation programs.

Calculation of joint fits of elastic sleeve-pin couplings with shafts

The causes of defects in the connections of elastic pin-sleeve couplings with shafts are analyzed. It was revealed that such defects as the wear of the mounting holes of the half-coupling and the bearing of the keys and grooves on the shaft and in the holes of the half-coupling are due to the lack of tightness in the shaft-coupling connection. An analysis of the standards for the manufacture of couplings and shaft ends showed that most of the recommended fits would not provide the specified durability of the joint due to the presence of gaps and small interferences, at which there would be a relative movement of the surfaces of the mating parts. A technique is developed for selecting fits for joints of elastic pin-sleeve couplings with shafts to increase their reliability and service life. The technique was tested on the example of calculating the fit of half-couplings on shafts for H 090.40 gearboxes, depending on the method of their assembly. As a result of calculations Ø50H8/v7 and Ø50H8/u8 fits were obtained, each of which differs from that recommended by the standard. Ø50H8/v7 fit has high interference and guarantees no twisting when transmitting torque. It is the most expedient to use the Ø50H8/u8 fit, obtained by assembling by heating the bushing, since it is more stable in the range of tightness with a lower accuracy of shaft processing and, therefore, the cost of shaft processing will be lower. Keywords: elastic pin-sleeve coupling, tightness, fit, limit tightness, fit tolerance, torque. metr@rgau-msha.ru

Calculation and selection of interference fits for restoring the shaft surface under the sealing ring by pressing thin-walled bushings

Methods for restoring shaft surfaces to nominal sizes are analyzed. It is recommended to use the thin-walled bushing method. The research used the principles of the theory of accuracy, interchangeability, and the theory of strength of materials. The input shaft of the ЯМЗ-239 engine gearbox was studied. As a result of research, a technique is developed that allows one to determine the interferences and select fits that guarantee clear fixation of pressed-in thin-walled bushings on the shaft. Keywords fit, cup-type seal, reliability, durability, interference, dimension tolerance, fit tolerance

When to shear dairy ewes: before breeding, during pregnancy or let them unshorn?

Shearing dairy ewes may improve their fitness and heat tolerance during late pregnancy, with positive effects on lambs and lactation performances. To test this hypothesis, two Mediterranean breeds (MN, Manchega, n = 43; LC, Lacaune, n = 28), differing in lactation performances and fleece traits, were submitted to three shearing strategies: (i) shorn before breeding (SBB), (ii) shorn at day 100 of pregnancy (S100) and (iii) unshorn (CO). Ewes were bred in spring and gestated during summer. Fleece traits and respiratory rate were measured on pregnant (107–121 days) resting ewes at different barn temperatures. Blood and colostrum were sampled at lambing. Ewes suckled their lambs (28 days) and were machine-milked until 180 days of lactation. Lamb and ewe weights, and condition score of the ewes, were recorded throughout the experiment. Milk yield was assessed during suckling (fortnightly) and milking (daily), and milk was sampled for composition (fortnightly). Fleece extension and wool weight at S100 were 13 and 45% greater in MN than in LC ewes, respectively, but the ewe’s respiration rate at late pregnancy, between 20 and 25 °C, did not vary among shearing treatments nor breeds. Nevertheless, S100 ewes had a 37% lower respiration rate than SBB and CO ewes at 28 °C. At lambing, SBB and S100 ewes had 86% higher glycaemia than CO in MN, but LC ewes did not vary. Shearing treatment had no effect in plasma insulin, β-hydroxybutyrate or non-esterified fatty acids (NEFAs) at lambing in both breeds. Lamb’s birthweight and growth during suckling did not differ by shearing treatment in both breeds. Colostrum composition and milk yield during suckling were not modified by shearing treatment in either breed, although S100 suckling milk composition increased in MN (protein and casein, 6%) and LC ewes (total solids, 8%; fat, 18%), compared to CO and SBB. No effects were detected in milk yield or composition during milking, but S100 tended to yield 28% more milk than CO in the LC ewes. The S100 treatment improved the body reserves in late pregnancy, when compared to CO and SBB in both breeds. In conclusion, shearing dairy ewes in late pregnancy was a recommendable management practice under summer conditions, because alleviated heat stress and improved the weight of the ewes, without detrimental effects on lambing and lactational performances, the last tending to increase milk yield in high-yielding dairy ewes.

A Dexamethasone Sparing-Regimen with Daratumumab and Lenalidomide in Frail Patients with Newly-Diagnosed Multiple Myeloma: Efficacy and Safety Analysis of the Phase 3 IFM2017-03 Trial

Background. Two-third of patients with newly diagnosed multiple myeloma (NDMM) are over the age of 65. Those patients have heterogeneous fitness and disparate tolerance to treatment. Frailty scoring systems have informed the stratification of elderly patients and treatment guidance. The use of long term dexamethasone is associated with multiple side effects specifically in elderly patients. Here we present the response rates and safety analysis of the randomized phase 3 IFM2017-03 trial, comparing daratumumab lenalidomide (DR) without long term dexamethasone to lenalidomide dexamethasone (Rd) in a frail population of patients with NDMM. Methods. Patients with NDMM over the age of 65 and with an ECOG proxy frailty score ≥ 2 were randomized 1:2 to receive 28-day cycles of lenalidomide (25mg/day, 21/28) and dexamethasone (20mg QW) or daratumumab (1800mg SC QW for 8 weeks, Q2W for 16 weeks and Q4W thereafter), lenalidomide (25mg/day, 21/28) and 2 cycles of dexamethasone (20mg QW for 8 weeks), until progression or unacceptable toxicity. Randomization was stratified on ISS and age. MRD by NGS at 10-5 was performed at 12 months for all patients. Interim analysis endpoints were overall response rate, VGPR or better rate, MRD rate and occurrence of grade 3 or more side effects. The present analysis was done at 12-months-therapy data cut. Results. In total, 295 patients were randomized (95 in Rd arm and 200 in DR arm). Median age was 81 years (68-92) with 84% of patients over the age of 75 years and 61% over the age of 80 years. Baseline demographics and disease characteristics were well balanced between arms. Overall response rates were 77% in Rd arm and 89% in DR arm (p=0.025). 12-months rates of VGPR or better were 42% and 58% in Rd and DR arms, respectively (p=0.013). Depth of response improved during treatment and the median time to reach VGPR was 11 months in Rd group and 5 months in DR group. Treatment benefit for DR was homogeneous across all subgroups defined by age, ECOG, Charlson, ISS, cytogenetics and creatinine clearance. Among patients with VGPR or better at 12 months, 63 were evaluable for MRD at 10-5 by NGS. MRD status at 12 months was negative in 18% of patients in Rd arm and 33% in DR arm (p=0.36). During the first year of treatment, at least one AE (grade ≥ 3) occurred in 64% and 76% of patients in Rd and DR arms, respectively (p=0.052). Patients in DR group had more grade ≥ 3 hematologic AE with neutropenia (Rd 15%, DR 44%, p<0.001) and anemia (Rd 2%, DR 11%, p=0.01) but similar grade ≥ 3 infections, with 17% in Rd and 13% in DR arms (p=0.38). Among patients with infections, 13 had COVID-19 (3 in Rd and 10 in DR). Discontinuations for AEs were similar in both arms (16% in Rd and 13% in DR, p=0.64). Conclusion. In this phase 3 trial dedicated for frail patients with NDMM, a dexamethasone-sparing regimen combining daratumumab and lenalidomide demonstrates deep and rapid responses and a favorable safety profile.

Calculation of Iron Loss with Stress in Stator Core by Shrinkage Tolerance

This paper presents a method for calculating the iron loss of the stator core of an electric motor owing to the stress generated by shrink fit tolerance in the production process. Shrink fit is used to fix the frame and stator core, shaft, and rotor core in a motor, and the corresponding condition varies depending on the material. Three finite element analysis steps were performed to reduce the iron loss owing to stress during shrinking of a frame and stator core. In step 1, the shrink fit process was applied to a frame and stator core, considering the manufacturing tolerances through three-dimensional modeling. Thermal-structure finite element analysis was performed to apply the same conditions as those in the shrink fit process. The shrink fit was expanded by applying heat to the frame, followed by natural cooling to calculate the contact stress between the frame and the stator core. In step 2, the same contact stress as that in step 1 was derived using structural analysis through two-dimensional modeling of the frame and stator core without tolerances. The contact stress was calculated by applying the equivalent thermal expansion coefficient of the frame, and it was confirmed that the manufacturing tolerance and maximum stress intensity are linearly related. In step 3, electromagnetic analysis was performed at the rated operating point of the 2.2-kW induction motor using the model obtained in step 2. The magnetic flux density distribution of the stator core was derived via electromagnetic analysis and the iron loss, including the stress distribution, realized in step 2. The iron losses obtained under different conditions, including the stress of the stator core owing to the shrink fit tolerance, were compared, and the effectiveness of the shrink fit tolerance required to achieve a motor with high efficiency was evaluated.

Determination of Cutting Transition Parameters in the APQP Pre-production Process of the Engine Camshaft Bearing Housing

An example of the application of the experimental planning method in the APQP pre-production process to find the values of the cutting process parameters that provide a given margin of accuracy is considered on the example of roughing and finishing boring of the inner hole of the camshaft bearing housing. From the total set of geometric parameters, special characteristics are highlighted - the size of the inner hole, which ensures the fit tolerance of the steel-fiber sleeve and the height parameter of roughness Ra, as well as radial runout. The objectives and results of the application of engineering methods (calculation of allowances, dimensional analysis, evaluation of technological accuracy of machine systems, planning experiments) as well as special methods of APQP process (quality management tools - FMEA analysis, SPS, MSA) are considered. Attention is drawn to the insufficient information content of the methods, which does not allow for the selection of process indicators to ensure the necessary margin of accuracy of special characteristics. In order to achieve a given margin of accuracy, technological components of the internal diametrical size are identified - the deviation of the tuning size, the deviation of the cross-section profile and the height roughness parameter Ra, the values of which are found as a result of production experiments. The planning of a full-factor experiment is carried out according to the parameters of the cutting process - cutting speed, feed and cutting depth. To implement the plan, special samples of products with a stepped allowance were designed and manufactured. The shape of the product samples makes it possible to reduce the number of samples for a full-factor experiment from eight to four, providing a check of the linearity of regression models. The calculation and regression models are given, which allow predicting the values of the components of the internal diametrical size at the design stage of the manufacturing operations of parts. The solution of the regression model system that satisfies the specified limitations for a given margin of accuracy allows you to find the optimal range of values of the parameters of the cutting process, to provide rare settings of special characteristics in the serial manufacturing process of camshaft bearing housings. Systematic application of the methodology, along with statistical methods of quality management, allows monitoring the technical condition of equipment and maintaining it in the condition required for the production of quality products. Systematic application of the methodology, along with statistical methods of quality management, allows monitoring the technical condition of equipment and maintaining it in the condition required for the production of quality products.