Strain Changes Research Articles

Experimental study on the desorption behavior of high-volatile bituminous coals following CO2 and CH4 injection at various compositional ratios

CO2-ECBM (Enhanced Coalbed Methane recovery) offers the dual benefits of increasing methane production and reducing carbon emissions through sequestration. Previous studies have primarily focused on the competitive adsorption effects of different gas compositions during the CO2-ECBM. However, the dynamic changes in desorption volume, desorption strain, and gas composition for different compositional ratios of CO2/CH4 after injecting CO2 remain unclear. Therefore, high-volatile bituminous coals from the southern margin of the Junggar Basin are chosen for desorption experiments with five different compositional ratios of CO2/CH4. Desorption volume, desorption strain, and gas composition of the coal samples are monitored during the desorption process. Finally, the mechanism influencing the dynamic changes in gas composition during desorption is analyzed. The results indicate that as CO2 concentration increases, both desorption volume and desorption strain correspondingly increase. At the same desorption volume, a higher CO2 concentration results in greater desorption strain. For different compositional ratios of CO2/CH4, CH4 concentration gradually decreases while CO2 concentration gradually increases over desorption time. The concentration of the desorption gas is influenced by the initial CO2 concentration and the pore structure. Specifically, higher initial CO2 concentrations, better pore opening, and more developed mesopores and macropores lead to greater changes in composition concentrations during desorption. Different concentrations of CO2 all promote CH4 production, with higher CO2 concentrations enhancing CH4 production efficiency more significantly, especially for samples that are more difficult to produce. The research findings can provide guidance for the efficient production of CBM after CO2 injection.

Telebehavioral Health for Caregivers of Children With Behavioral Health Needs to Address Caregiver Strain: Cohort Study.

Behavioral health conditions among children have worsened over the past decade. Caregivers for children with behavioral health conditions are at risk for two types of caregiver strain: (1) an objective strain, that results directly from the child's condition and (2) subjective strain, that arises from the caregiver's feelings regarding these events. This study aimed to evaluate the impact of a technology-enabled pediatric and family behavioral health service on caregivers' strain among a commercially insured population. We also explore the common symptom clusters of caregiver strain to better understand the caregiver presentation to inform future care planning. We examined changes in caregiver strain using the Caregiver Strain Questionnaire-Short Form 7 over the course of their child's web-based behavioral health care between 2021 and 2023 using a pre-post study design. Common caregiver strain symptom clusters were identified using Ward hierarchical agglomerative clustering. The majority of children were White 60.8% (1002/1647), female 53.6% (882/1647), and aged between 5 and 9 years (33.7%, 555/1647). Families fall broadly into 4 groups based on what drives caregiver strain the most, namely those experiencing (1) disrupted family relationships and time interruption, (2) missed work, (3) worried about their child's future and feeling tired and sad, and (4) financial strain. Caregiver strain, which was associated with the child's disease severity (P<.001), decreased significantly in all therapeutic groups. Web-based family-oriented behavioral health care can improve caregiver strain and reduce family and time disruptions, missed work, and financial strain. Sources of caregiver strain vary and may be overlooked when relying on the conventional scoring of the Caregiver Strain Questionnaire-Short Form 7.

A Hermetic Package Technique for Multi-Functional Fiber Sensors through Pressure Boundary of Energy Systems Based on Glass Sealants

This paper presents a hermitic fiber sensor packaging technique that enables fiber sensors to be embedded in energy systems for performing multi-parameter measurements in high-temperature and strong radiation environments. A high-temperature, stable Intrinsic Fabry–Perot interferometer (IFPI) array, inscribed by a femtosecond laser direct writing scheme, is used to measure both temperature and pressure induced strain changes. To address the large disparity in thermo-expansion coefficients (TECs) between silica fibers and metal parts, glass sealants with TEC between silica optical fibers and metals were used to hermetically seal optical fiber sensors inside stainless steel metal tubes. The hermetically sealed package is validated for helium leakages between 1 MPa and 10 MPa using a helium leak detector. An IFPI sensor embedded in glass sealant was used to measure pressure. The paper demonstrates an effective technique to deploy fiber sensors to perform multi-parameter measurements in a wide range of energy systems that utilize high temperatures and strong radiation environments to achieve efficient energy production.

Evaluation of physiological and thermal comfort effectiveness of ceiling fan and table fan during a heat wave

Heat waves are becoming a significant global concern as they have substantial repercussions on human health. Further, the adverse impact of heat waves on health will likely worsen globally. The use of electric fans is an energy-saving and sustainable cooling strategy against heat waves, but current health guidelines discourage fan use during heat waves. Previous research has shown that health guidelines underestimated the evaporative cooling impact of fans. These studies mainly focused on the effects of table fans on various physiological parameters of occupants in hot environments. Nevertheless, the air movement produced by both table fans and ceiling fans may influence the occupants’ physiological and perceptual responses significantly. Hence, the present study investigated the effectiveness of no-fan, table-fan and ceiling-fan conditions during heat waves through an experimental approach. Sixteen healthy young participants were exposed to an air temperature of 41.0 ± 0.5 °C and relative humidity of 35 ± 2 % for 2 hours. The participants’ physiological parameters and perceptual responses were collected. We found that both table and ceiling fans delay the changes in thermoregulatory and cardiovascular strain compared to the no-fan scenario. Moreover, table fans minimize physiological strain and provide greater comfort than ceiling fans. Hence, people should opt for table fans over ceiling fans during heat waves.

Investigating the dielectric and ferromagnetic behaviour of Ni and Co dual doped ZnO for diluted magnetic semiconductor

Herein, Ni/Co co-doped ZnO nanoparticles (NPs) were successfully prepared via chemical co-precipitation process. The structural, purity and crystallite size of as-prepared particles were confirmed by using x-ray diffraction (XRD). The results revealed the hexagonal wurtzite structure of ZnO without any impurity phase of as-prepared samples. The crystallite size decreased from 34.9 to 9.6 nm, whereas lattice strain reduced to 0.00086. The change in crystallite size, lattice parameters, strains and dislocation density further indicates the successful incorporation of dopants in ZnO host lattice. The dielectric properties, ac conductivity, and magnetic behaviour were steadily examined. The dielectric constant has been found to be 1070 with 5wt% at low frequency and become constant at higher frequency. It was revealed that dopant additions lead to attain high dielectric constant and low loss possibly attributed to interface polarization, and dipole polarization due to oxygen vacancy defects. M-H measurement observed that ferromagnetism at room temperature pure and doped ZnO samples. The ferromagnetic behaviour of pure ZnO NPs with Ms = 0.17 emu g−1, Mr = 0.11 emu g−1 and Hc = 67 which was increased to Ms = 0.85 emu g−1 and Mr = 0.65 emu/g for 5wt% Co. This improvement with increasing Co concentration indicates that oxygen defects may stabilize the ferromagnetic order. These interesting features encouraging to use this material for ultrahigh dielectric materials and spintronics.

Identification of Novel Independent Correlations between Cellular Components of the Immune System and Strain-Related Indices of Myocardial Dysfunction in CKD Patients and Kidney Transplant Recipients without Established Cardiovascular Disease.

The role of immune system components in the development of myocardial remodeling in chronic kidney disease (CKD) and kidney transplantation remains an open question. Our aim was to investigate the associations between immune cell subpopulations in the circulation of CKD patients and kidney transplant recipients (KTRs) with subclinical indices of myocardial performance. We enrolled 44 CKD patients and 38 KTRs without established cardiovascular disease. A selected panel of immune cells was measured by flow cytometry. Classical and novel strain-related indices of ventricular function were measured by speckle-tracking echocardiography at baseline and following dipyridamole infusion. In CKD patients, the left ventricular (LV) relative wall thickness correlated with the CD14++CD16- monocytes (β = 0.447, p = 0.004), while the CD14++CD16+ monocytes were independent correlates of the global radial strain (β = 0.351, p = 0.04). In KTRs, dipyridamole induced changes in global longitudinal strain correlated with CD14++CD16+ monocytes (β = 0.423, p = 0.009) and CD4+ T-cells (β = 0.403, p = 0.01). LV twist and untwist were independently correlated with the CD8+ T-cells (β = 0.405, p = 0.02 and β = -0.367, p = 0.03, respectively) in CKD patients, whereas the CD14++CD16+ monocytes were independent correlates of LV twist and untwist in KTRs (β = 0.405, p = 0.02 and β = -0.367, p = 0.03, respectively). Immune cell subsets independently correlate with left ventricular strain and torsion-related indices in CKD patients and KTRs without established CVD.

Diagnosis of spine pseudoarthrosis based on the biomechanical properties of bone

BACKGROUND CONTEXTFailure to fuse following anterior cervical discectomy and fusion (ACDF) may result in symptomatic pseudoarthrosis. Traditional diagnosis involves computerized tomography to detect bridging bone and/or flexion-extension radiographs to assess whether segmental motion is above specific thresholds; however, there are currently no well-validated diagnostic tests. We propose a biomechanically rational approach to achieve a reliable diagnostic test for pseudoarthrosis. PURPOSEDevelop and test a biomechanically based approach to the diagnosis of pseudoarthrosis. STUDY DESIGNLiterature review, development of theory, re-analysis of a previously published study with surgical exploration as the gold-standard, and retrospective analysis of pooled studies to understand time to fusion. METHODSFully automated methods were used to measure disc space strains (change in disc space height divided by initial height). Measurement error combined with the reported failure strain of trabecular bone led to a proposed strain threshold for diagnosis of pseudoarthrosis following ACDF. We reanalyzed previously reported flexion-extension radiographs for asymptomatic volunteers to assess whether flexion-extension radiographs, in the absence of fusion surgery, can be expected to provide sufficient stress on motion segments to allow for reliable strain-based fusion assessment. The sensitivity and specificity of strain- and rotation-based pseudoarthrosis diagnosis were assessed by reanalysis of previously reported post-ACDF flexion-extension radiographs, where intraoperative fusion assessments were also available. Finally, we assessed changes in strain over time using 9,869 flexion-extension radiographs obtained 6 weeks to 84 months post-ACDF surgery from 1,369 patients. RESULTSThe estimated error in automated measurement of disc space strain from radiographs was approximately 3%, and the reported failure strain of bridging bone was less than 2.5%. On that basis, we propose a 5% strain threshold for pseudoarthrosis diagnosis. Reanalysis of a study in which intraoperative fusion assessments were available revealed 67% sensitivity and 82% specificity for strain-based diagnosis of pseudoarthrosis, which was comparable to rotation-based diagnosis. Analysis of post-ACDF flexion-extension radiographs revealed rapid strain reduction for up to 24 months, followed by a slower decrease for up to 84 months. When rotation is less than 2 degrees, the strain-based diagnosis differed from the rotation-based diagnosis in approximately 14% of the cases. CONCLUSIONSWe propose steps for standardizing diagnosis of pseudoarthrosis based on the failure strain of bone, measurement error, and retrospective data. These steps include obtaining high-quality flexion-extension studies, the application of proposed diagnostic thresholds, and the use of image stabilization for conclusive diagnosis, when motion is near thresholds. The necessity for an accurate diagnosis with minimal radiation exposure underscores the need for further optimization and standardization in diagnosing pseudoarthrosis following ACDF surgery. CLINICAL SIGNIFICANCEIn a symptomatic postspine fusion patient, it is important to diagnose or rule-out pseudoarthrosis. There are currently no well-validated diagnostic tests for this condition. Incorporating strain-based intervertebral motion analysis into the diagnosis could lead to a standardized and validated test for detecting spine pseudoarthrosis.

Mechanical properties of AlCoCrCuFeNi high-entropy alloys using molecular dynamics and machine learning

High-entropy alloys (HEAs) stand out from multi-component alloys due to their attractive microstructures and mechanical properties. In this investigation, molecular dynamics (MD) simulation and machine learning (ML) were used to ascertain the deformation mechanism of AlCoCrCuFeNi HEAs under the influence of temperature, strain rate, and grain sizes. First, the MD simulation shows that the yield stress decreases significantly as the strain and temperature increase. In other cases, changes in strain rate and grain size have less effect on mechanical properties than changes in strain and temperature. The alloys exhibited superplastic behavior under all test conditions. The deformity mechanism discloses that strain and temperature are the main sources of beginning strain, and the shear bands move along the uniaxial tensile axis inside the workpiece. Furthermore, the fast phase shift of inclusion under mild strain indicates the relative instability of the inclusion phase of hexagonal close-packed (HCP). Ultimately, the dislocation evolution mechanism shows that the dislocations are transported to free surfaces under increased strain when they nucleate around the grain boundary. Surprisingly, the ML prediction results also confirm the same characteristics as those confirmed from the MD simulation. Hence, the combination of MD and ML reinforces the confidence in the findings of mechanical characteristics of HEA. Consequently, this combination fills the gaps between MD and ML, which can significantly save time, human power, and cost to conduct real experiments for testing HEA deformation in practice.

Wavelength-Dependent Bragg Grating Sensors Cascade an Interferometer Sensor to Enhance Sensing Capacity and Diversification through the Deep Belief Network

Fiber-optic sensors, such as fiber Bragg grating (FBG) sensors and fiber-optic interferometers, have excellent sensing capabilities for industrial, chemical, and biomedical engineering applications. This paper used machine learning to enhance the number of fiber-optic sensing placement points and promote the cost-effectiveness and diversity of fiber-optic sensing applications. In this paper, the framework adopted is the FBG cascading an interferometer, and a deep belief network (DBN) is used to demodulate the wavelength of the sampled complex spectrum. As the capacity of the fiber-optic sensor arrangement is optimized, the peak spectra from FBGs undergoing strain or temperature changes may overlap. In addition, overlapping FBG spectra with interferometer spectra results in periodic modulation of the spectral intensity, making the spectral intensity variation more complex as a function of different strains or temperature levels. Therefore, it may not be possible to analyze the sensed results of FBGs with the naked eye, and it would be ideal to use machine learning to demodulate the sensed results of FBGs and the interferometer. Experimental results show that DBN can successfully interpret the wavelengths of individual FBG peaks, and peaks of the interferometer spectrum, from the overlapping spectrum of peak-overlapping FBGs and the interferometer.

Reproducibility Analysis of Two Speckle Tracking Software for the Antenatal Semiautomated Assessment of the Fetal Cardiac Function

Introduction: Speckle tracking echocardiography is a non-Doppler modality allowing the semiautomated evaluation of the fetal cardiac function by tracking the speckles of the endocardial borders. Little evidence is available on the evaluation and comparison of different software for the functional assessment of the fetal heart by means of speckle tracking echocardiography. The aim of this study was to evaluate the reproducibility and agreement of two different proprietary speckle tracking software for the prenatal semiautomated assessment of the fetal cardiac function. Methods: The prospective study including non-anomalous fetuses was referred for different indications at two tertiary academic units in Italy (University of Parma) and Spain (University of Barcelona). Two-dimensional clips of the four-chamber view of the fetal heart were acquired by two dedicated operators using high-end ultrasound machines with a frame rate higher than 60 Hz. The stored clips were pseudo-anonymized and shared between the collaborating units. Functional echocardiographic analyses were independently performed using the two proprietary software (TomTec GmbH and FetalHQ®) by the same operators. Inter-software reproducibility of the endocardial global longitudinal strain (EndoGLS) and fractional area change (FAC) of the left (LV) and the right ventricles (RV) and ejection fraction (EF) of the LV were evaluated by the intraclass correlation coefficient (ICC). Results: Forty-eight fetuses were included at a median of 31+2 (21+6–40+3) gestational weeks. Moderate reproducibility was found for the functional parameters of the LV: EndoGLS (Pearson’s correlation 0.456, p < 0.01; ICC 0.446, 95% CI: 0.189–0.647, p < 0.01); EF (Pearson’s correlation 0.435, p < 0.01; ICC 0.419, 95% CI: 0.156–0.627, p < 0.01); FAC (Person’s correlation 0.484, p < 0.01; ICC 0.475, 95% CI: 0.223–0.667, p < 0.01). On the contrary, RV functional parameters showed poor reproducibility between the two software: EndoGLS (Pearson’s correlation 0.383, p = 0.01; ICC 0.377, 95% CI: 0.107–0.596, p < 0.01) and FAC (ICC 0.284, 95% CI: 0.003–0.524, p = 0.02). Conclusion: Our results demonstrate a moderate reproducibility of the speckle tracking analysis of the LV using TomTec GmbH and FetalHQ®, with poor reproducibility for RV analysis.

Experimental study on test of wheel-rail impact based on iron plate strain of fastener system

The wheel-rail impact load can reach up to 3–4 times the normal wheel load, with two peaks including a high-frequency impact force (P1) and a mid-frequency or quasi-static impact force (P2). To effectively monitor the wheel-rail impact, this study utilizes strain gauges adhered to bottom of iron plates of fastener to measure rail-seat force, and conducts indoor static load and wheel-drop tests. A finite element model is established for verification and analysis. By analyzing the transmission law of the wheel-rail impact, a monitoring method through rail-seat force is proposed. The results reveal that the strain change of the iron plate in the static load test remains stable and exhibits a linear relationship with rail-seat force. Through a full-scale wheel-drop test, it demonstrates that rail-seat force can effectively monitor P2 force of wheel-rail impact. Compared to traditional method of directly adhering strain gauges to rail, the method of adhering strain gauges to iron plate enabled wheel-rail impact invalid test sections measurement. The peak value of wheel-rail impact P2 can be deduced from peak value of rail-seat force under different impact location, impact levels, and elastic pad stiffness. The proposed monitoring method of based on fastener iron plate strain offers a more efficient alternative for identifying wheel defects and rail defects.

Size-strain distribution analysis from XRD peak profile of (Mg, Fe) co-doped SnO2 nanoparticles fabricated using chemical co-precipitation route

In this study, we synthesize pristine and (Mg, Fe) co-doped SnO2 nanoparticles using the chemical co-precipitation method, where the Mg doping amount is fixed (2 mol%) and the amount of Fe is varied between 2 and 6 mol%. The narrow and sharp natures of intense XRD peaks notify that the crystallinity is pretty well. The formation of the single-phase tetragonal rutile type structure of all prepared compounds has been identified by Rietveld refinement, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. Moreover, the well incorporation of Fe and Mg in SnO2 and absence of any other unexpected elements are confirmed by the energy dispersive X-ray spectroscopy. How the co-doping of Mg and Fe alter the crystallite size, microstrain, and dislocation density of the prepared samples have been investigated by Scherrer method with various modified version of it, Williamson-Hall method (W–H) in three factions (UDM, USDM, and UDEDM), Size strain plot (SSP) method, Halder-Wagner (H–W) method, Wagner-Aqua (W-A) method, and Warren-Averbach (WA) method. The obtained crystallite size using the WA method is smaller than the other methods and Scherrer-based methods show much comparable (except SLMSE) sizes. Additionally, the W–H, H–W, SSP, and W-A plots show almost similar tendency of decreasing crystal size, increasing dislocation density and lattice strain with increasing doping. The scanning electron microscopy (SEM) profiles revealed that the synthesized nanoparticles are agglomerated in nature, where the agglomeration increases with decreasing crystal size. The magnetic response of the prepared samples revealed a weak ferromagnetic (or soft magnetic) nature, where saturation magnetization increased due to doping, and a reducing trend of remanent magnetization and coercivity was explored which indicates the phase transition from ferromagnetic to paramagnetic. However, this soft magnetic nature was modified with the influence of defects like changes in lattice parameters, strain, and oxygen vacancy. This phase transition at higher doping concentration makes our nanomaterial as a suitable contender for memory devices, hyperthermia treatment, and photothermal effect.

Sensor Systems for Measuring Force and Temperature with Fiber-Optic Bragg Gratings Embedded in Composite Materials

Currently, there is a lot of interest in smart sensors and integrated composite materials in various industries such as construction, aviation, automobile, medical, information technology, communication, and manufacturing. Here, a new conceptual design for a force and temperature sensor system is developed using fiber-optic Bragg grating sensors embedded within composite materials, and a mathematical model is proposed that allows one to estimate strain and temperature based on signals obtained from the optical Bragg gratings. This is important for understanding the behaviors of sensors under different conditions and for creating effective monitoring systems. Describing the strain gradient distribution, especially considering different materials with different Young’s modulus values, provides insight into how different materials respond to applied forces and temperature changes. The shape of the strain gradient distribution was obtained, which is a quadratic function with a maximum value of 1500 µ, with a maximum value at the center of the lattice and a symmetrically decreasing strain value with distance from the central part of the fiber Bragg grating. With the axial strain at the installation site of the Bragg grating sensor under applied force values ranging from 10 to 11 N, the change in strain was linear. As a result of theoretical research, it was found that the developed system with fiber-optic sensors based on Bragg gratings embedded in composite materials is resistant to external influences and temperature changes.

Mechanical strain effect on the optoelectronic properties and photocatalysis applications of layered AlN/GaN nanoheterostructure.

The aim of this work is to use first principles calculations to examine the effects of different mechanical strains on the optoelectronic and photocatalytic capabilities of the 2D/2D nanoheterostructure of AlN/GaN. By utilizing the lmBJ (Meta-GGA) and PBEsol (GGA) functional, the bandgap of the nanoheterostructure is calculated and found to be 4.89eV and 3.24eV. Simulated 2D AlN/GaN nanoheterostructure exhibits exceptional optical and electronic characteristics under applied biaxial tensile and compressive strains. The band gap changes from 4.89 to 3.77eV, while the energy gap nature transitions from direct to indirect during tensile strain fluctuations of 0% to 8%. Strain is also found to have a significant effect on the optical absorption peaks. And a 0-8% rise in tensile strain causes the initial absorption peak of the 2D AlN/GaN nanoheterostructure to shift from 4.88 to 4.20eV, which results in a 14% red shift in photon energy for every 2% change in strain. Furthermore, the optimum bandgap and band edge positions of the 2D AlN/GaN nanoheterostructure enable the water redox process to produce hydrogen and oxygen for wide range of pH. Thus, modification via strain may be an effective method for altering the optical as well as electronic characteristics of a 2D AlN/GaN nanoheterostructure, and this study may pave the way for new applications of this material in optoelectronic devices in the future. In the current work, density functional theory is used to explore every attribute of the 2D AlN/GaN nanoheterostructure. To characterize the electronic exchange-correlation, we used the PBEsol functional. In order to prevent any interlayer contact between periodicity of images, a vacuum is produced along the z-direction of approximately 10 Å. To increase the precision of bandgap prediction, the electronic and optical characteristics were computed using the meta-GGA lmBJ functional. To account for interlayer van der Waals interactions, nanoheterostructure computations were performed using the DFT-D3 functional.

Acoustomotive diffuse correlation spectroscopy for sensing mechanical stiffness in tissue-mimicking phantoms.

Many diseases, such as inflammation, dropsy, or tumors, often cause alterations in the mechanical stiffness of human tissues. Ultrasound-based techniques are commonly adopted in clinics for stiffness assessment, whereas optical methodologies hold promise for sensing strain changes and providing optical information pertaining to the microcirculatory network, thereby facilitating comprehensive measurements of tissue physiopathology. Diffuse correlation spectroscopy (DCS), an emerging dynamic light scattering technique, has been used to capture the enhanced motion of light scatterers induced by acoustic radiation force (ARF). Theoretically, the amplitude of this enhanced scatterers motion is related to the medium stiffness. Based on this relationship, we report a light coherent technique that combines ARF and DCS to qualitatively evaluate changes in the stiffness of medium. We experimentally demonstrate the accuracy and feasibility of this technique for probing stiffness in homogeneous phantom by comparing it with independent ultrasound methods. Additionally, we explore a potential application of this technique in distinguishing between fluid filled lesion and homogeneous tissue through heterogeneous phantom experiments. This unique combination of ARF and DCS, namely, acoustomotive DCS (AM-DCS), would provide an alternative way to measure particle-motion related stiffness, thereby assisting in the diagnosis and treatment of diseases.

A four core fiber temperature and strain dual parameter sensor based on T-shaped taper

A four core fiber temperature and strain dual parameter sensor based on T-shaped taper is proposed and prepared. The sensor is composed of single-mode fiber (SMF), multi-mode fiber (MMF), and four core fiber (FCF). Among them, MMF plays a role in beam expansion, and FCF is tapered and fused with SMF to form a T-shaped taper structure, thereby preparing a sensor based on Mach Zehnder interference principle. When the external environmental temperature and strain change, due to thermal effect and elastic optical effect, the refractive index of the FCF cladding and fiber core changes differently, resulting in shift in the interference spectrum. Based on the temperature and strain sensitivity at different interference valleys, the temperature and strain dual parameter matrix equation of the sensor can be obtained. The experimental results indicate that when the temperature rises within the range of 30 ℃ to 90 ℃, the sensor spectrum shows a red shift phenomenon, and the maximum temperature sensitivity can reach 55 pm/ ℃. When the strain increases within the range of 0 με∼ 2000 με, the transmission spectrum of the sensor exhibits a blue shift phenomenon, and the maximum strain sensitivity can reach −2.6 pm/ με. Finally, based on the experimental results, the matrix equation for dual parameter sensing can be obtained. This sensor is easy to manufacture and has high sensitivity. It can measure sensing parameters normally in micro magnetic and micro electric field environments.

Genetic background affects neutrophil activity and determines the severity of autoinflammatory osteomyelitis in mice.

The knowledge about the contribution of the innate immune system to health and disease is expanding. However, to obtain reliable results, it is critical to select appropriate mouse models for in vivo studies. Data on genetic and phenotypic changes associated with different mouse strains can assist in this task. Such data can also facilitate our understanding of how specific polymorphisms and genetic alterations affect gene function, phenotypes, and disease outcomes. Extensive information is available on genetic changes in all major mouse strains. However, comparatively little is known about their impact on immune response and in particular on innate immunity. Here, we analyzed a mouse model of chronic multifocal osteomyelitis (CMO), an autoinflammatory disease driven exclusively by the innate immune system, which is caused by an inactivating mutation in the Pstpip2 gene. We investigated how the genetic background of BALB/c, C57BL/6J, and C57BL/6NCrl strains alters the molecular mechanisms controlling disease progression. While all mice developed the disease, symptoms were significantly milder in BALB/c and partially also in C57BL/6J when compared to C57BL/6NCrl. Disease severity correlated with the number of infiltrating neutrophils and monocytes and with the production of chemokines attracting these cells to the site of inflammation. It also correlated with increased expression of genes associated with autoinflammation, rheumatoid arthritis, neutrophil activation, and degranulation, resulting in altered neutrophil activation in vivo. Together, our data demonstrate striking effects of genetic background on multiple parameters of neutrophil function and activity influencing the onset and course of the CMO disease.

(Invited) Tackling Interface Challenges for Shallow Diamond Color Centers

Spin defects in wide-bandgap semiconductors, such as color centers in diamond, can be highly sensitive to local (nanoscale) changes in magnetic field, temperature, and strain. These solid-state quantum sensors have certain advantages over their atomic counterparts owing to their room-temperature operation without the need for vacuum components and the relative ease of photonic- and RF-component integration. However, near-surface quantum defects exhibit spin decoherence and most of the light emitted is trapped within the bulk crystal due total internal reflection at the interface. In this presentation, I will summarize our recent work towards better understanding and addressing these interface challenges, including the modeling and experimental characterization of radiative emission of near-surface emitters, design of nanophotonic components to improve light extraction, and surface analysis and chemical termination techniques aimed at improving spin coherence of emitters.

Recruitment-to-inflation ratio to assess response to PEEP during laparoscopic surgery: A physiologic study

Study objectiveDuring laparoscopic surgery, the role of PEEP to improve outcome is controversial. Mechanistically, PEEP benefits depend on the extent of alveolar recruitment, which prevents ventilator-induced lung injury by reducing lung dynamic strain. The hypotheses of this study were that pneumoperitoneum-induced aeration loss and PEEP-induced recruitment are inter-individually variable, and that the recruitment-to-inflation ratio (R/I) can identify patients who benefit from PEEP in terms of strain reduction. DesignSequential study. SettingOperating room. PatientsSeventeen ASA I-III patients receiving robot-assisted prostatectomy during Trendelenburg pneumoperitoneum. Interventions and measurementsPatients underwent end-expiratory lung volume (EELV) and respiratory/lung/chest wall mechanics (esophageal manometry and inspiratory/expiratory occlusions) assessment at PEEP = 0 cmH2O before and after pneumoperitoneum, at PEEP = 4 and 12 cmH2O during pneumoperitoneum. Pneumoperitoneum-induced derecruitment and PEEP-induced recruitment were assessed through a simplified method based on multiple pressure-volume curve. Dynamic and static strain changes were evaluated. R/I between 12 and 4 cmH2O was assessed from EELV. Inter-individual variability was rated with the ratio of standard deviation to mean (CoV). Main resultsPneumoperitoneum reduced EELV by (median [IqR]) 410 mL [80–770] (p < 0.001) and increased dynamic strain by 0.04 [0.01–0.07] (p < 0.001), with high inter-individual variability (CoV = 70% and 88%, respectively). Compared to PEEP = 4 cmH2O, PEEP = 12 cmH2O yielded variable amount of recruitment (139 mL [96–366] CoV = 101%), causing different extent of dynamic strain reduction (median decrease 0.02 [0.01–0.04], p = 0.002; CoV = 86%) and static strain increases (median increase 0.05 [0.04–0.07], p = 0.01, CoV = 33%). R/I (1.73 [0.58–3.35]) estimated the decrease in dynamic strain (p ≤0.001, r = −0.90) and the increase in static strain (p = 0.009, r = −0.73) induced by PEEP, while PEEP-induced changes in respiratory and lung mechanics did not. ConclusionsTrendelenburg pneumoperitoneum yields variable derecruitment: PEEP capability to revert these phenomena varies significantly among individuals. High R/I identifies patients in whom higher PEEP mostly reduces dynamic strain with limited static strain increases, potentially allowing individualized settings.

Abstract Mo024: Integrated analysis of ex vivo biomechanical ventricular remodeling and imaging-based in vivo strain changes in a pre-clinical murine model of radiation-induced cardiotoxicity

Introduction: Thoracic radiation therapy (RT) is commonly used for the treatment of many common malignancies, such as lung and breast cancer, but carries a high risk of radiation-induced cardiotoxicity (RIC). Existing diagnosis of RIC is challenged by subclinical ventricular dysfunction, not captured by global indices of cardiac function. Understanding RIC-driven biomechanical remodeling of the myocardium will provide novel insights into developing high-fidelity imaging approaches for early detection of RIC. Methods: A pre-clinical model of RIC was developed by administering whole heart irradiation under image guidance in mice (8 Gy x 5) over five consecutive days. A longitudinal study was carried out to investigate the biomechanical response of the left ventricle (LV). Cardiac magnetic resonance imaging was performed to estimate end-systolic strains. Mechanical testing was performed on the harvested LV free wall (LVFW) specimens to measure passive stiffness, calculated as the tangent to the ensemble stress-strain curve at 30% strain. Results: A significant increase in passive LVFW stiffness was observed at 3M post-RT (Figs. 1A and B). Significant declines in both global circumferential strain (GCS) and global radial strain (GRS) at 3M post-RT, compared to respective measurements at pre-RT, were observed (Figs. 1C and D). Suppressed contractile strains suggested biomechanical remodeling of the LV, including impaired contractility and passive stiffening of the LVFW, consistent with ex-vivo measurements. Conclusion: We have established a direct correlation between ex-vivo mechanical testing (elevated stiffness) and reduced contractile strains in in-vivo analysis in a mouse model of RIC. Such integrated analysis will pave the way towards developing highly sensitive imaging approaches that non-invasively recapitulate the ventricular remodeling events associated with RIC, thereby enabling early detection of RIC in patients receiving thoracic RT.