Relaxation Effects Research Articles

Effectiveness of smartphone-based virtual reality relaxation (SVR) for enhancing comfort in cancer patients undergoing chemotherapy: a randomized controlled trial.

Comfort, anxiety, and pain significantly impact the quality of life and treatment adherence in cancer patients undergoing chemotherapy. Virtual reality (VR) technology offers a novel non-pharmacological intervention to address these primary concerns. While vital signs provide objective physiological data, they are considered secondary outcomes that may reflect changes in patients' subjective experiences. This study aims to evaluate the effectiveness of smartphone-based virtual reality relaxation (SVR) interventions on improving comfort and reducing anxiety and pain (primary outcomes) in patients with cancer undergoing chemotherapy. Additionally, it assesses the impact on blood pressure and pulse rate (secondary outcomes). This prospective, two-arm, randomized controlled trial involved 99 cancer patients undergoing chemotherapy who were randomized into the SVR group (n = 50) and control group (n = 49) from March to May 2023. The SVR group received a 10-min immersive VR experience featuring 360-degree natural scenery videos with relaxing sounds, while participants in the control group received standard care and guided imagery leaflets. The primary outcomes-comfort, anxiety, and pain-were evaluated at various time points: comfort was assessed at baseline and post-chemotherapy, while anxiety and pain were assessed at four stages (pre-chemotherapy, pre-VR, immediate post-intervention, and post-chemotherapy). Secondary outcomes included vital signs (blood pressure and pulse rate), which were assessed at the same four stages. Cybersickness symptoms were examined post-chemotherapy. Data analysis involved independent t tests, linear regression, and Generalized Estimating Equations (GEE). Among 99 randomized patients, the SVR group reported significantly higher comfort levels (p = 0.01; Cohen's d = 0.4), reduced anxiety (p = 0.01; Cohen's d = 0.50), and pain (p = 0.015; Cohen's d = 0.35) compared to the control group. No significant differences were found in heart rate (p = 0.92), systolic blood pressure (p = 0.36), or diastolic blood pressure (p = 0.95). The majority of participants (66-96%) in the SVR group did not report cybersickness symptoms. SVR shows promise as an intervention for improving comfort and reducing anxiety and pain in cancer patients undergoing chemotherapy. Healthcare providers at chemotherapy centers should consider incorporating VR devices and curated content into patient care routines. ClinicalTrials.gov: NCT05756465, registered on January 22, 2023.

Manganese Oxide Nanoparticles for MRI-Based Multimodal Imaging and Theranostics

Manganese-based MRI contrast agents have recently attracted much attention as an alternative to Gd-based compounds. Various nanostructures have been proposed for potential applications in in vivo diagnostics and theranostics. This review is focused on the discussion of different types of Mn oxide-based nanoparticles (MnxOy NPs) obtained at the +2, +3 and +4 oxidation states for MRI, multimodal imaging or theranostic applications. These NPs show favorable magnetic properties, good biocompatibility, and an improved toxicity profile relative to Gd(III)-based nanosystems, showing that the Mn paramagnetic ions offer advantages for the next generation of nanoscale MRI and theranostic contrast agents. Their potential for enhancing relaxivity and MRI contrast effects is illustrated through discussion of selected examples published in the past decade.

Understanding the Finite Size and Surface Relaxation Effects on the Surface States of Bi2Se3 Family Topological Insulators

Understanding the Finite Size and Surface Relaxation Effects on the Surface States of Bi₂Se₃ Family Topological Insulators

The impact of the type of playful massage movements on the perception of tactile stimulation in children: EEG study

Tactile play and playful massage are a normal interaction between adults and children in many cultures. Experimental data show that activation of the C-tactile system during such playful touches contributes to children’s socialization and the establishment of psychoemotional bonds in the parent-child dyad. However, comprehensive studies of the effects of different types of touch on perception of tactile stimulation in children have not been conducted before. Twenty-three children participated in the present study: 10 in the preschool age group and 13 in the elementary school age group. Children in both groups received play massage containing different types of touch with simultaneous recording of electroencephalogram (EEG) and heart rate. EEG processing included determination of spectral power, alpha rhythm peak frequency and fractal dimension. Analysis of the results showed that the relaxing effect of the procedure was more pronounced in children of primary school age, which can be explained both by the greater maturity of the CNS and the greater need for tactile contact, which is not realized in the school environment.

In vitro skin permeation of flavonoid esters enzymatically derived from natural oils: release mechanism from gel emulsion, stability, and dermatological compatibility

Due to their broad spectrum of biological activities and attractive pharmacological properties, flavonoids are very promising molecules for application in skin care products. In this study, phloridzin and naringin medium- and long-chain fatty acid esters were enzymatically synthesized in reaction with natural oils (coconut and linseed oil) and in vitro transdermal delivery of synthesized esters through artificial Strat-M® membrane was investigated. Experimental results were succesfully fitted using Peppas and Sahlin model which includes the lag phase. Release kinetics of all examined flavonoid esters from gel emulsions through the membrane depended on both diffusion and polymer relaxation effect (0.5<n < 1). The estimated effective diffusion coefficients ranged from 0.168·10-8 to 6.149·10-8 cm2 s-1 for phloridzin esters and from 0.116·10-8 to 4.210·10-8 cm2 s-1 for naringin esters. The effective diffusion coefficients decreased with the increase in ester molecular weight indicating the size-dependent diffusion. All formulation showed good stability, excellent hydration effect, and excellent dermatological compatibility without irritating effect. It can be concluded that gel emulsions with a mixture of flavonoid esters enzymatically synthesized in reaction with vegetable oils can be effectively topically applied as a skin care products.

Novel Pharmaceutical Cocrystal Consisting of Chlorzoxazone and Nicotinamide: A New Promising Carrier for Solubility Augmentation.

Chlorzoxazone (CHZ) is a centrally acting muscle relaxant used to treat muscle spasms. It is employed as a first-line medication for treating muscle spasms, offering both musculoskeletal relaxation and mild sedative effects. According to the biopharmaceutics classification system, it belongs to class II drug having poor solubility and high permeability. In order to improve the flow property, water solubility, and dissolution of CHZ, CHZ-nicotinamide (NA) cocrystal was prepared by liquid-assisted grinding cocrystallization (LAG CC) method using methanol as the choice of solvent. CHZ-NA cocrystal was characterized by differential scanning calorimeter (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectrometry, and scanning electron microscopy (SEM). DSC scan showed a sharp endothermic peak shift, which is caused by the formation of a new crystal form with altered physical properties, which was further confirmed by PXRD. Also, a change in the surface morphology of LAG CC compared to CHZ was observed in SEM. The resultant CHZ-NA cocrystal displayed improved powder flow properties compared to the native form of CHZ. LAG CC demonstrated a 3.1- and 2.6-fold increase in saturated solubility and intrinsic dissolution rate, respectively, compared to CHZ alone. Furthermore, the in vitro dissolution study showed that the cumulative dissolution of CHZ in 2 h was about 53%. Whereas, dissolution of LAG CC reached 99% in 2 h, showing obvious dissolution improvement. Thus, CHZ-NA cocrystal could significantly improve the flow properties, solubility and dissolution of CHZ.

The Psychophysiological Relaxation Effects of Essential Oil Combined with Still-Life Painting Activities on Older Adults in Taiwan During the COVID-19 Pandemic.

Although the COVID-19 pandemic affected all types of people, older adults were disproportionately affected. Therefore, we developed an indoor program inspired by art and natural elements (plant essential oils [EOs]) intended to have a relaxing effect akin to a forest atmosphere to enhance psychophysiological health during this period. Thirty Taiwanese older adults (range, 59-79 years) participated in the study. We combined an art activity (still-life painting of vegetables) with the inhalation of Pseudotsuga menziesii and Lavandula angustifolia EOs during a 100-minute experiment. The study showed that physiological measures (heart rate, normalized low-frequency heart variability, the ratio of low- to high-frequency heart variability, high-beta waves, and gamma waves) decreased during the experiment; correspondingly, increased standard deviation of normal-to-normal intervals, normalized high-frequency heart variability, and high-alpha waves were observed, indicating relaxed physiological state. Subjective psychological assessments using the State-Trait Anxiety Inventory-State showed lower posttest scores, further supporting the relaxation effects. The psychophysiological data from this study provide important scientific evidence for the physical and mental health benefits of indoor nature-based activity programs for older adults, thereby improving their quality of life.

Research on Adhesion Pull-Off Behavior of Rigid Flat Punch and Viscoelastic Substrate

Interfacial adhesion is one of the key factors affecting the reliability of micro–nano systems. The adhesion contact mechanism is still unclear as the time-dependent viscoelasticity of soft materials. To clarify the adhesion interaction, the pull-off detachment between the rigid flat punch and viscoelastic substrate is explored considering the viscoelasticity of soft materials and rate-dependent adhesion. Taking the Lennard-Jones (L-J) potential characterizing interfacial adhesion and the Prony series defining the viscoelasticity of materials as references, the bilinear cohesion zone model (CZM) and standard Maxwell model are employed, and an adhesion analysis framework is established by combining finite element technology. The influence laws of the loading and unloading rates, material relaxation coefficients and size effect on adhesion pull-off behavior are revealed. The results show that the pull-off force is independent of the material relaxation effect and related to the unloading rate. When v^ ≥ 50 or v^ &lt; 0.01, the pull-off force has nothing to do with the unloading rate, but when 0.01 &lt; v^ &lt; 50, the pull-off force increases with the increasing unloading rate. Also, it is controlled by the size effect, and the changing trend conforms to the MD-n model proposed by Jiang. The energy required for interfacial separation (i.e., effective adhesion work) is a result of the comprehensive influence of unloading rates, material properties and the relaxation effect, which is consistent with Papangelo1’s research results. In addition, we derive the critical contact radius of the transition from the Kendall solution to the strength control solution. This work not only provides a detailed solution for the interfacial adhesion behavior but also provides guidance for the application of adhesion in Micro-Electro-Mechanical Systems (MEMSs).

Exploring Antidepressant and Skeletal Muscle Relaxant Effects of the Hydroalcholic Extract of the Sedum lineare Thunb

Exploring Antidepressant and Skeletal Muscle Relaxant Effects of the Hydroalcholic Extract of the Sedum lineare Thunb

The Effect of Combined Foot Massage and Nature Music on the Sleep Quality of Critically Ill Patients

Aims: Critical patients in ICU and HCU often experience poor sleep due to excessive stress and various symptoms like environmental factors, pain, noise, anxiety, and physical discomfort. Foot massage and natural music interventions can help meet their sleep needs, providing a relaxing effect and improving physical and psychological conditions. The purpose of this study is to determine the effect of providing combination therapy of foot massage and natural music therapy in Dr. Hospital's peacock room Salamun 2023. Methods: This type of research is pre-experimental with a pre-post test of one group and uses the Richard Champbell Sleep Questionnaire (RCSQ). Then the data was processed using a paired sample T-test. The sample in this study is 16 respondents. Results: The results of the statistical test obtained a p-value of 0.01, meaning that there was an effect between the pretest and posttest of the combination of foot massage and natural music therapy on the quality of sleep in critical patients in the peacock room at Dr. Salamun Hospital, Bandung City, 2023. Conclusions : the conclusion of this study is that there is an effect of foot massage therapy and natural music on the sleep quality of critical patients as shown by the results of measuring the quality of critical patients before and after consecutive interventions with massage of both feet combined with natural music. For 10 minutes it has been proven to be able to improve sleep quality in critically ill patients so that this intervention can be applied as a therapy to improve sleep quality.

Effectiveness of Finger Hand Relaxation and Progressive Muscle Relaxation Techniques on Anxiety in Pre-Operative Sectio Caesarea Patients

Background: Anxiety is a common thing that occurs in patients who will undergo surgery. The anxiety that occurs in preoperative patients can be felt from the time they are scheduled for surgery until the time of surgery arrives. Anxiety management can be done using pharmacological and non-pharmacological therapy. Purpose: The aim of this research is to analyze the effectiveness of finger grip relaxation techniques and progressive muscle relaxation on anxiety in pre-caesarean section surgery patients in the Kediri Regency Regional General Hospital. Method: This study used a Quasy-experiment With Pretest Posttest to determine the effect of finger grip and progressive muscle relaxation techniques. The sample selection in this study used a purposive sampling technique and a total of 56 patients were obtained who were divided into 2 groups, namely the finger grip intervention group and the progressive muscle intervention group. The pretest and posttest data for each group were then analyzed using the Wilcoxon Test to determine the effect and the Mann-Whitney Test to compare the posttest results of the 2 groups. Results: The results of the study showed that the Wilcoxon test in both intervention groups obtained a p-value &lt; α (0.05), which means that before and after the intervention, both progressive muscle relaxation and finger grip relaxation had an influence on the anxiety level of pre-caesarean section patients. For the results of the Mann-Whitney test, the p-value was 0.063 or p-value &gt; α (0.05), which means there was no significant difference between changes in anxiety whether those given progressive muscle relaxation intervention or finger grip relaxation. Conclusion: Finger grip relaxation techniques and progressive muscle relaxation techniques are both effective in reducing anxiety levels in pre-caesarean section surgery patients. So this non- pharmacological therapy can be an option for patients in dealing with anxiety problems before caesarean section surgery.

Impact of COVID-19 restrictions liberalization on air quality: a case study of Chongqing, Southwest China.

To mitigate the societal impact of the COVID-19 pandemic, China implemented long-term restrictive measures. The sudden liberalization at the end of 2022 disrupted residents' daily routines, making it scientifically intriguing to explore its effect on air quality. Taking Chongqing City in Southwest China as an example, we examined the impact of restriction liberalization on air quality, identified potential sources of pollutants, simulated the effects of abrupt anthropogenic control relaxation using a Random Forest Model, and applied an optimized model to predict the post-liberalization pollutant concentrations. The results showed increases in PM2.5 (72.3%), PM10 (67.7%), and NO2 (21.9%) concentrations, while O3 concentration decreased by 20.5%. Although potential pollution source areas contracted, pollution levels intensified with northeastern Sichuan, interior Chongqing, and northern Guizhou being major contributors to pollutant emissions. Anthropogenic emissions accounted for 26.7 ~ 33% changes in PM2.5 and PM10 concentrations while meteorological conditions contributed to 40.2 ~ 43.3% variations observed during the period. The optimized model demonstrated a correlation between predicted and observed values with R2 ranging from 0.70 to 0.89, enabling accurate prediction of post-liberalization pollutant concentrations. This study can enhance our understanding regarding the impact of sudden social lockdown relaxation events on air quality while providing support for urban air pollution prevention.

Effects of Anisotropy, Convection, and Relaxation on Nonlinear Reaction-Diffusion Systems

The effects of relaxation, convection, and anisotropy on a two-dimensional, two-equation system of nonlinearly coupled, second-order hyperbolic, advection–reaction–diffusion equations are studied numerically by means of a three-time-level linearized finite difference method. The formulation utilizes a frame-indifferent constitutive equation for the heat and mass diffusion fluxes, taking into account the tensorial character of the thermal diffusivity of heat and mass diffusion. This approach results in a large system of linear algebraic equations at each time level. It is shown that the effects of relaxation are small although they may be noticeable initially if the relaxation times are smaller than the characteristic residence, diffusion, and reaction times. It is also shown that the anisotropy associated with one of the dependent variables does not have an important role in the reaction wave dynamics, whereas the anisotropy of the other dependent variable results in transitions from spiral waves to either large or small curvature reaction fronts. Convection is found to play an important role in the reaction front dynamics depending on the vortex circulation and radius and the anisotropy of the two dependent variables. For clockwise-rotating vortices of large diameter, patterns similar to those observed in planar mixing layers have been found for anisotropic diffusion tensors.

Cavity-modified local and non-local electronic interactions in molecular ensembles under vibrational strong coupling.

Resonant vibrational strong coupling (VSC) between molecular vibrations and quantized field modes of low-frequency optical cavities constitutes the conceptual cornerstone of vibro-polaritonic chemistry. In this work, we theoretically investigate the role of complementary nonresonant electron-photon interactions in the cavity Born-Oppenheimer (CBO) approximation. In particular, we study cavity-induced modifications of local and non-local electronic interactions in dipole-coupled molecular ensembles under VSC. Methodologically, we combine CBO perturbation theory (CBO-PT) [E. W. Fischer and P. Saalfrank, J. Chem. Theory Comput. 19, 7215 (2023)] with non-perturbative CBO Hartree-Fock (HF) and coupled cluster (CC) theories. In a first step, we derive up to second-order CBO-PT cavity potential energy surfaces, which reveal non-trivial intra- and inter-molecular corrections induced by the cavity. We then introduce the concept of a cavity reaction potential (CRP), minimizing the electronic energy in the cavity subspace to discuss vibro-polaritonic reaction mechanisms. We present reformulations of CBO-HF and CBO-CC approaches for CRPs and derive second-order approximate CRPs from CBO-PT for unimolecular and bimolecular scenarios. In the unimolecular case, we find small local modifications of molecular potential energy surfaces for selected isomerization reactions dominantly captured by the first-order dipole fluctuation correction. Excellent agreement between CBO-PT and non-perturbative wave function results indicates minor VSC-induced state relaxation effects in the single-molecule limit. In the bimolecular scenario, CBO-PT reveals an explicit coupling of interacting dimers to cavity modes besides cavity-polarization dependent dipole-induced dipole and van der Waals interactions with enhanced long-range character. An illustrative CBO-coupled cluster theory with singles and doubles-based numerical analysis of selected molecular dimer models provides a complementary non-perturbative perspective on cavity-modified intermolecular interactions under VSC.

Spatiotemporal evolution of post-seismic deformation caused by large earthquakes around the Pacific and its impact on plate movement

SUMMARY The fully relaxed deformation caused by an earthquake refers to the total deformation of the earth caused by the earthquake, including the coseismic deformation and the total effect of post-seismic stress relaxation in the mantle on crustal deformation. An in-depth investigation into post-seismic and fully relaxed deformation resulting from large earthquakes is conducive to comprehending the feedback effect of earthquakes on plate motion. In this paper, we first calculated theoretically the coseimic, post-seicmic and fully relaxed deformations caused by the Tohoku-Oki Mw9.0 earthquake using the spherical dislocation theory. The post-seismic displacement caused by the great earthquake leads to the continuous convergence of plates on both sides of the seismogenic fault, which will certainly facilitate the downward insertion of the subduction plate. As time goes by the influence range of seismic deformations becomes larger and larger. The Tohoku-Oki Mw9.0 earthquake can produce &amp;gt;5 cm of cumulative post-seismic horizontal displacement at a far place like the East Pacific Rise over 100 millenniums. Then, we built slip models of 375 earthquakes with Mw7.0 and above in the circum-Pacific seismic belt, calculated the cumulative post-seismic deformations of them, and found that significant post-seismic horizontal displacements covered the entire Pacific Ocean. The post-seismic deformation field caused by the 2011 Tohoku-Oki Mw9.0 earthquake, the 2010 Chile Mw8.8 earthquake, the 1964 Prince William Sound Mw9.1 earthquake and the 1960 Chile Mw(9.3–9.4) earthquake determines the overall distribution pattern of the deformation field in the Pacific region. Those large earthquakes around the Pacific make the total Pacific Plate present a tension strain in the northwest–southeast direction. The one at the East Pacific Rise reaches 300–400 nstr, with orientation of principle strain approximately perpendicular to the Rise. This tensile strain is bound to encourage transverse expansion of the mid-ocean ridge. By a logical extension, the post-seismic stress relaxation in the mantle caused by past earthquakes should be an important driving force for the current plate movement, in addition to the classic driving force like negative buoyancy and plate material phase transition. This study proves theoretically that there is a two-way relationship between great earthquakes and plate movement, and the viscous structure of mantle plays a key role in the relationship.

Magnesium sulphate: Current application in anaesthesia

The role of magnesium in medicine has advanced considerably over the two decades. It is now generally accepted that magnesium is a crucial nutrient, and its deficiency has adverse effects on a variety of physiological processes. Magnesium deficiency should be avoided in the perioperative period. Magnesium has been developed as a drug with various clinical uses. It is a key cation in physiological processes, and its homeostasis is essential for the normal function of human body organs. Magnesium sulphate is a mineral pharmaceutical preparation of magnesium. It has a high therapeutic index and cost-effectiveness. Magnesium sulphate is readily available, affordable and its use in clinical practice is associated with less complications. Recently, the potentiation of effects of muscle relaxation and perioperative analgesia has drawn the attention of anaesthetists to the use of magnesium sulphate in anaesthesia and pain management. The characteristics features of magnesium sulphate as a vasodilator, ability to protect the blood brain barrier, reduction of cerebral oedema and central anticonvulsant action make it very useful in intensive care.

Delivery system for dexamethasone phosphate based on a Zn2+-crosslinked polyelectrolyte complex of diethylaminoethyl chitosan and chondroitin sulfate

Hybrid nano- and microparticles based on metal ion crosslinked biopolymers are promising carriers for the development of drug delivery systems with improved biopharmaceutical properties. In this work, dexamethasone phosphate-containing particles based on chondroitin sulfate and chitosan or diethylaminoethyl chitosan additionally crosslinked with Zn2+ were prepared. Depending on the polycation/polyanion ratio in the system, anionic and cationic polyelectrolyte complexes (PECs) were obtained. The anionic Zn2+-containing and Zn2+-free PECs had sizes of 154 and 180 nm and ζ-potentials of −22.4 and −27.5 mV, respectively. The cationic Zn2+-containing and Zn2+-free PECs had sizes of 242 and 362 nm and ζ-potentials of 22.4 and 24.7 mV, respectively. The presence of Zn2+ in the system significantly prolonged the release of dexamethasone phosphate from the hybrid polyelectrolyte particle. The resulting release profiles of dexamethasone phosphate were in agreement with the Peppas-Sahlin kinetic model, which considers the combined effects of Fickian diffusion and polymer chain relaxation on the drug release rate. It was shown that the prolongation of drug release was mainly due to swelling and relaxation of the Zn2+ crosslinked polymers. The developed particles exhibited good mucoadhesive properties and pronounced anti-inflammatory activity, making them attractive candidates for biomedical applications.

Effectiveness of Contract-relax Vs Post-isometric Relaxation in Hamstring Tightness in Healthy Young Adults

Objective: The objective of the study was to compare the effectiveness of Post-isometric Relaxation Technique VS Contract-Relax Technique to improve hamstring flexibility in healthy young adults. Method: Total 30, male and female participants,15 in each group, i.e. Group A &amp; Group B between the age group 18 to 24 years were selected from RJS Group of Institutes, Kopargaon using random sampling method according to the inclusion and exclusion criteria. Pre-assessment of active knee extension range of motion (ROM) was done using Active Knee Extension (AKE) test with the universal full- circle goniometer and Reading 1 was noted for each subject. The subjects in Group A were given Post-isometric relaxation, 8 seconds for 12 days and Group B were given Contract-Relax Technique, 17 seconds for 12 days. Reading 2 &amp; Reading 3 were noted on the 6th and 12th day of the treatment session respectively. Results: The results indicate a statistically significant difference between Group A and Group B. The t-value of 5.908 and p-value of less than 0.01 provides significant support for the alternative hypothesis of Hypothesis 1. The Mean values of Group B [4.44] is significantly higher than that for Group A [2.36] which suggests that Contract-Relax technique showed more significant increase in the Active knee extension range of motion than the Post-isometric relaxation after 12 days of treatment protocol. Conclusion: The statistical data results concluded that Contract-relax technique is more effective than Post-isometric relaxation technique in improving the hamstring flexibility in healthy young adults.

Effectiveness of Combined Pulmonary Rehabilitation and Progressive Muscle Relaxation in Treating Long-Term COVID-19 Symptoms: A Randomized Controlled Trial

Background: The aim of this study was to investigate the effects of pulmonary rehabilitation (PR) and additional progressive muscle relaxation (PMR) techniques in patients with long-term COVID-19 symptoms. Methods: We included 61 patients with long COVID-19 symptoms and randomly assigned them to two groups: PR only (group 1 with 30 subjects) and PR with PMR (group 2 with 31 subjects). The PR program consisted of gradual aerobic conditioning, strength training, and breathing exercises. Group 2 received additional 20 min daily sessions of progressive muscle relaxation techniques. Results: Following a 21-day intervention, it was observed that both groups had noteworthy improvements in lung function, exercise capacity, and sleep quality with statistical significance (p &lt; 0.0001). Group 2 showed significant improvements in overall health (as measured by the General Health Questionnaire-12), patient health (as assessed by the Patient Health Questionnaire-9), general anxiety levels (as indicated by the Generalized Anxiety Disorders Scale-7), and sleep quality (as measured by the Pittsburgh Sleep Quality Index), with statistical significance (p &lt; 0.0001), compared to group 1. Moreover, the statistical analysis demonstrated no significant difference in exercise capacity improvement between group 1 and group 2, as indicated by a p-value of 0.1711. Conclusions: The addition of progressive muscle relaxation to pulmonary rehabilitation significantly enhances mental health outcomes, particularly in reducing anxiety and improving sleep quality, for patients with long-term COVID-19 symptoms. These findings suggest that incorporating PMR into PR programs offers a valuable non-pharmacological approach to improving overall patient well-being during long-term COVID-19 recovery.

Fatigue notch strengthening effect of nickel-based single crystal superalloys under different stress ratios

Nickel-based single crystal superalloys (Ni-SXs) are widely used in turbine blades of aircraft engines. With the increasing demand for higher temperature-bearing capacity, the introduction of film cooling holes, impingement holes, and trailing edge slots for cooling induces stress concentration, which compromises the structural integrity of the blades, generates complex multiaxial stress states, and adversely affects their operational performance. In this study, Ni-SXs, DD6, was utilized to investigate the influence of stress ratios on fatigue performance under complex stress states. Low cycle fatigue (LCF) tests were carried out at different stress ratios with stress concentration coefficient Kt = 1.0, 2.0 and 3.0. The results indicate that the notched specimens exhibit a significant fatigue notch strengthening effect under high stress ratios. The fracture surface and microstructure also indicate that under high stress ratios loading, the notches exhibit significant creep failure characteristics. This means that the main cause of fatigue notch strengthening is similar to creep notch strengthening effect. A macroscopic anisotropic constitutive model coupled with damage was developed and applied to finite element analysis of notched specimens. The results demonstrate that as the stress ratio rises, the stress relaxation effect at the notch becomes more pronounced, yet the level of damage diminishes. Additionally, a stress-equivalent model based on Bridgman stress was proposed, which effectively unifies the lifetime trends of notched and smooth specimens, predicting lifetimes within a threefold error band.