Ultrasound Speed Research Articles

Intrarater and Interrater Reliability of Quantitative Ultrasound Speed of Sound by Trained Raters at the Distal Radius in Postmenopausal Women.

Quantitative ultrasound (QUS) performed at the distal radius shows potential as an effective tool for evaluating fracture risk, especially in postmenopausal women, but the reliability of this tool has not been reported in this patient population. This study investigated the within-day intrarater and interrater reliability of trained raters performing QUS measures at the distal radius of postmenopausal community-dwelling women. Eighteen women between the ages of 56 and 87years were recruited from senior centers in the Greenville area of South Carolina and consented to participate. A QUS bone sonometer was used in this study; the trained raters performed 3 repeated speed of sound (SOS) measures at the nondominant radius of each participant on the same day. Intraclass correlation coefficients (ICCs) were calculated (model 3,1 for intrarater and 2,3 for interrater reliability) to determine the reliability within and between raters. In addition, we calculated the standard error of measurement (SEM) and the minimal detectable change at 95% confidence interval (MDC 95 ). The within-day intrarater reliability was excellent for both physical therapist raters (ICC (3,1) ranging from 0.93 to 0.91). The SEM and MDC for the within-day intrarater reliability measures were small for both raters (SEM=36.79-38.75 or 0.92%-0.97% of the pooled mean; MDC 95 =101.99-107.40). The interrater reliability for SOS measurements using radial QUS was good with an ICC (2,3) of 0.77 (95% CI, 0.36-0.92) for 3 averaged measures. The SEM and MDC were larger for the interrater reliability measures (SEM=62.79 or 1.57% of the pooled mean; MDC 95 =174.05). Quantitative ultrasound SOS measurement at the distal radius showed excellent within-day intrarater and good interrater (when 3 measures were averaged) reliability in community-dwelling postmenopausal women. The SEM and MDC 95 were also low for interrater reliability when a mean of 3 trials was used. This study is the first to demonstrate that this particular QUS device at the radius may be a reliable fracture risk screening tool for postmenopausal women.

Genome-wide study identifies novel genes associated with bone toxicities in children with acute lymphoblastic leukaemia.

Bone toxicities are common among paediatric patients treated for acute lymphoblastic leukaemia (ALL) with potentially major negative impact on patients' quality of life. To identify the underlying genetic contributors, we conducted a genome-wide association study (GWAS) and a transcriptome-wide association study (TWAS) in 260 patients of European-descent from the DFCI 05-001 ALL trial, with validation in 101 patients of European-descent from the DFCI 11-001 ALL trial. We identified a significant association between rs844882 on chromosome 20 and bone toxicities in the DFCI 05-001 trial (p = 1.7 × 10-8). In DFCI 11-001 trial, we observed a consistent trend of this variant with fracture. The variant was an eQTL for two nearby genes, CD93 and THBD. In TWAS, genetically predicted ACAD9 expression was associated with an increased risk of bone toxicities, which was confirmed by meta-analysis of the two cohorts (meta-p = 2.4 × 10-6). In addition, a polygenic risk score of heel quantitative ultrasound speed of sound was associated with fracture risk in both cohorts (meta-p = 2.3 × 10-3). Our findings highlight the genetic influence on treatment-related bone toxicities in this patient population. The genes we identified in our study provide new biological insights into the development of bone adverse events related to ALL treatment.

Advanced ultrasound techniques for studying liquid–liquid dispersions in confined impinging jets

Advanced ultrasound techniques were used to study liquid–liquid dispersed flows formed in impinging jets confined in small channels. Ultrasound speed and attenuation coefficient spectra of the propagated sound waves were used to obtain volume fraction and drop size distributions, respectively. The results were compared against drop size distributions obtained with high-speed imaging. Experiments were conducted in a 2 mm internal diameter tube for both kerosene oil continuous and glycerol/water continuous dispersions. The overall mixture flow rate was set at 60 ml/s, and the dispersed phase fractions were 0.02, 0.05, and 0.10. The measured volume fractions were found to be very close to the input ones, indicating a very small slip between the phases in the dispersed flows. From the ultrasound measurements, the drop size distributions were found to range from 32 to 695 μm under the different conditions used. The drop sizes at the two low input volume fractions were in reasonable agreement with the results from the imaging. Imaging, however, could not be used for the 0.10 input dispersed phase fraction. These results demonstrate the applicability of the ultrasound techniques to measurements in dispersed liquid–liquid flows in small channels.

Evaluating building stones: Physical-mechanical changes from high-temperature fire and water cooling

Heritage sites built with natural stone are at risk from fires, which can alter stone properties and compromise its structural integrity. Over 60 studies in the past three decades have examined fire impact on natural stone, providing insights for their prevention and restoration. The primary objectives are to develop effective strategies to mitigate fire risks, protect heritage structures, and ensure the preservation of our cultural legacy. Two noteworthy Portuguese limestones used as heritage building materials: Lioz (LL) and grey Ançã stone (GAS), were studied regarding the effect of high-temperature exposure for simulating fire at 200 °C, 400 °C and 600 °C, followed by cooling in water to reproduce fire extinguish in natural stone buildings. The findings provided insights into how the different temperatures impact the stone morphological, physical and mechanical properties. Color measurements (CIE L*a*b*) showed a color difference from 3 to 32 %; SEM-EDS confirmed microstructure modifications after fire exposure with cracks formation and intragranular porosity development. Among the diverse physical and mechanical properties of the stones, uniaxial compressive strength decreased from 1 to 33 %, Leeb D hardness decreased up to 12.2 %, lowering in open porosity was detected in the range 70–289 % and ultrasound speed propagation were significantly affected after thermal cycle at 600 °C with a negative variation reaching 49 %. Results from TGA show a loss of mass due to retained water (∼40 °C) and loss of hydration water at ∼ 120 °C in both limestones. The total mass loss (∼42–∼44 %) is associated with the loss of H2O, CO2. In conclusion, stones with higher toughness and compression strength exhibited reduced damage at high temperatures due to their enhanced resistance to fracturing under stress. As limestone's mechanical strength decreases under high temperatures, it's advisable to increase its thickness to ensure sufficient support for loads and intended conditions of use. The deficiency of analysis on limestone's mechanical decay from fire reveals a significant knowledge gap regarding the complete extent of damage and deterioration in stone heritage structures.

Impact of Curing Periods on the Evaluation of Thermal, Mechanical Properties, and Energy Consumption of Concrete Buildings

This study examines the impact of the curing period on the thermal and mechanical properties of concrete and its subsequent effect on building energy consumption. The research methodology is divided into two parts: experimental and simulation. In the experimental section, concrete specimens were created using regular concrete with a dosage of cement of 350 Kg/m³, and curing periods were varied (without curing, 3, 7, 14, 21, and 28 days) to assess thermal conductivity, density, ultrasonic pulse velocity, and compressive strength at 28 days. The results indicated that compressive strength increased by 71% between uncured and 28-day cured specimens, ultrasound propagation speed increased by 15%, and thermal conductivity increased by 31% with longer curing periods. A simulation using TRNSYS software estimated the energy consumption of a reference building with varying concrete properties based on the curing period. The simulated building consisted of three rooms, a hall, and a kitchen, with double exterior walls of 25 cm thickness and interior walls of 10 cm thickness. The findings revealed that longer curing periods contributed to increased energy consumption in the building. This study provides valuable insights into the relationship between curing periods, concrete properties, and their effect on the energy efficiency of concrete buildings.

Clinical value of endoscopic ultrasound sound speed in differential diagnosis of pancreatic solid lesion and prognosis of pancreatic cancer.

Differential diagnosis of pancreatic solid lesion (PSL) and prognosis of pancreatic cancer (PC) is a clinical challenge. We aimed to explore the differential diagnostic value of sound speed (SS) obtained from endoscopic ultrasonography (EUS) in PSL and the prognostic value of SS in PC. Patients with PSL in The Third Xiangya Hospital of Central South University from March 2019 to October 2019 were prospectively enrolled, who obtained SS from PSL. Patients were divided into the PC group and the pancreatic benign lesion (PBL) group. SS1 is the SS of lesions and SS2 is the SS of normal tissues adjacent to lesions. Ratio1 is equal to SS1 divided by SS2 of PSL (ratio1 = SS1/SS2). Eighty patients were enrolled (24 PBL patients, 56 PC patients). SS1 and ratio1 in PC group were higher compared with PBL group (SS1:1568.00 vs. 1550.00, Z = -2.066, p = 0.039; ratio1: 1.0110 vs. 1.0051, Z = -3.391, p = 0.001). The SS1 in PC (Z = -6.503, p < 0.001) was higher compared to SS2. In the nonsurgical group of PC, low ratio1 predicted high overall survival (OS) (7.000 months vs. 4.000 months; p = 0.039). In the surgical group of PC, low SS1 was associated with low median OS (4.000 months vs. 12.000 months; p = 0.033). SS plays a vital role in distinguishing between PBL and PC. Higher SS1 and ratio1 obtained by EUS are more related to PC than PBL. In PC patients, high SS1 may predict pancreatic lesions. In the nonsurgical group of PC, low ratio1 may predict high OS. However, in the surgical group of PC, low SS1 may predict low OS.

A polygenic score associated with fracture risk in breast cancer patients treated with aromatase inhibitors

Identifying women at high risk of osteoporotic fracture from aromatase inhibitor (AI) therapy for breast cancer is largely based on known risk factors for healthy postmenopausal women, which might not accurately reflect the risk in breast cancer patients post-AI therapy. To determine whether a polygenic score associated with fracture in healthy women is also significant in women treated with AIs for breast cancer, we used data from a prospective observational cohort of 2152 women diagnosed with hormonal receptor positive breast cancer treated with AIs as the initial endocrine therapy and examined a polygenic score of heel quantitative ultrasound speed of sound (gSOS) in relation to incident osteoporotic fracture after AI therapy during a median 6.1 years of follow up after AI initiation. In multivariable models, patients with the second and third highest tertiles (T) versus the lowest tertile of gSOS had significantly lower risk of fracture (T2: adjusted HR = 0.61, 95% CI: 0.46-0.80; T3: adjusted HR = 0.53, 95% CI: 0.40-0.70). The lower risk of fracture in patients with the highest tertile of gSOS remained significant after further adjustment for BMD at the hip (T3: adjusted HR = 0.62, 95% CI: 0.42-0.91). In conclusion, our analysis showed gSOS as a novel genetic predictor for fracture risk independent of BMD among breast cancer patients treated with AIs. Future studies are warranted to evaluate the performance of incorporating gSOS in prediction models for the risk of AI-related fracture in breast cancer patients.

Ultrasound shear wave speeds reduced following hamstring strain injury but not after returning to sport

ObjectivesThe purpose of the study was to investigate differences in ultrasound shear wave speed (SWS) between uninjured and injured limbs following hamstring strain injury (HSI) at time of injury (TOI), return to sport (RTS), and 12 weeks after RTS (12wks).MethodsThis observational, prospective, cross-sectional design included male and female collegiate athletes who sustained an HSI. SWS imaging was performed at TOI, RTS, and 12wks with magnetic resonance imaging. SWS maps were acquired by a musculoskeletal-trained sonographer at the injury location of the injured limb and location-matched on the contralateral limb. The average SWS from three 5 mm diameter Q-boxes on each limb were used for analysis. A linear mixed effects model was performed to determine differences in SWS between limbs across the study time points.ResultsSWS was lower in the injured limb compared to the contralateral limb at TOI (uninjured – injured limb difference: 0.23 [0.05, 0.41] m/s, p = 0.006). No between-limb differences in SWS were observed at RTS (0.15 [-0.05, 0.36] m/s, p = 0.23) or 12wks (-0.11 [-0.41, 0.18] m/s, p = 0.84).ConclusionsThe SWS in the injured limb of collegiate athletes after HSI was lower compared to the uninjured limb at TOI but not at RTS or 12 weeks after RTS.Critical relevance statementHamstring strain injury with structural disruption can be detected by lower injured limb shear wave speed compared to the uninjured limb. Lack of between-limb differences at return to sport may demonstrate changes consistent with healing. Shear wave speed may complement traditional ultrasound or MRI for monitoring muscle injury.Key points• Ultrasound shear wave speed can non-invasively measure tissue elasticity in muscle injury locations.• Injured limb time of injury shear wave speeds were lower versus uninjured limb but not thereafter.• Null return to sport shear wave speed differences may correspond to structural changes associated with healing.• Shear wave speed may provide quantitative measures for monitoring muscle elasticity during recovery.Graphical

Genetic susceptibility and late bone outcomes in childhood acute lymphoblastic leukemia survivors.

Childhood acute lymphoblastic leukemia (cALL) survivors are at increased risk for bone comorbidities, but accurate screening tools for such comorbidities are limited. Polygenic scores (PGS) could stratify cALL survivors for risk of long-term adverse bone outcomes. We evaluated 214 (51% female) cALL survivors from the Prévenir les Effets TArdifs de la LEucémie study (median age 21yr). Bone mineral density (BMD) measurements were obtained using dual X-ray absorptiometry at the lumbar spine (LS-BMD), femoral neck (FN-BMD), and total body (TB-BMD), and vertebral fractures (VF) were documented using the vertebral deformity criterion. We computed a PGS for adult heel quantitative ultrasound speed of sound (gSOS), known to be associated with the risk of osteoporotic fracture, using imputed genotype data of the participants, and tested it for association with BMD Z-scores and VF risk, adjusting for clinical risk factors, and in sex and prognostic risk-stratified analyses. We found that a gSOS below the mean was associated with lower BMD in all three sites in univariate and multivariate models. In univariate analyses, 1 SD increase in gSOS conferred a 0.16 SD increase in LS-BMD (95% CI 0.005-0.31), whereas a gSOS above the mean was associated with a 0.31 SD higher LS-BMD (95% CI 0.008-0.61), a 0.36 SD higher TB-BMD (95% CI 0.06-0.67), and a 0.43 SD higher FN-BMD (95% CI 0.13-0.72). Models combining gSOS with clinical risk factors explained up to 16% of the variance of BMD phenotypes and obtained an area under the receiver operating characteristic curve for VF of 0.77 in subgroup analyses. Cranial radiation, high cumulative glucocorticoid doses, high risk group, and male sex were significant risk factors for lower BMD Z-scores. In conclusion, a PGS, in combination with clinical risk factors, could be used as a tool to risk stratify cALL survivors for treatment-related bone morbidity.

Assessment of risk factors for osteopenia development in premature babies

Neonatal osteopenia (KB 61.3 (ICD-11)) – violation of mineral exchange of bone tissue (BT) of premature babies (PB). Predicting and detection of osteopenia is the key to its successful control.&#x0D; Aim. The aim of the article was to determine risk factors influencing the formation of neonatal osteopenia of PB and during the term of intensive care / postintensive nursing.&#x0D; Materials and methods. Ultrasound densitometer Sunlight Omnisense 9000 was used to measure the ultrasound speed in BT (SOS, m/s) with estimation Z-score (SD) according to gestational age of 56 PB and 20 mature babies (control group) in the early neonatal age. Verification of osteopenia was carried out under the WHO guidelines for radiation methods by Z-score indicator less than SD by -1.0. Estimation of Z-score -2.0 SD and less was attributed to ultra-low indicators. The characteristics of obstetric and gynecological, somatic anamnesis and pregnancy course of premature babies’ mothers, factors of PB postnatal development that influence the formation of BT were studied.&#x0D; Results. Children born at 33 weeks or earlier are 3.23 times more likely (OR = 3.23; CI 95 % [1.08; 9.70]) to develop BT demineralization by the corresponding term of birth than other PB. The chances of ultra-low SOS by Z-score are 14.22 times higher (OR = 14.22; CI 95 % [3.29; 61.57]) in PB born at 32 weeks of gestation and earlier. Extragenital diseases, clinical signs of calcium deficiency in mothers, and women’s intake of calcium and vitamin D3 during pregnancy did not have a statistically significant difference (p &gt; 0.05) in the studied PB and control group. The mother’s preeclampsia increases the chances of insufficient BT mineralization by 5.47 times (OR = 5.47; CI 95 % [1.07; 27.93]), second parity pregnancy (and subsequent ones) – by 4.51 times (OR = 4.51, CI 95 % [1.38; 14.80]). The factors of the ratio of the duration of mechanical ventilation relative to the total time of PB treatment, the duration of parenteral feeding have an inverse correlation (moderate (r = -0.42, р &lt; 0.05) and significant (r = -0.51, р &lt; 0.05) respectively) with a decrease in SOS to low Z-score.&#x0D; Conclusions. In PB born at 32 weeks of gestation and earlier, the chances of ultra-low SOS indicators by Z-score are 14.22 times higher (OR = 14.22; CI 95 % [3.29; 61.57]). The following factors predicts insufficient mineralization of BT according to SOS indicators according to the Z-score: mother’s second parity pregnancy (and subsequent ones), preeclampsia, parenteral feeding of PB for more than 8 days (Se = 75.00 %, Sp = 71.87 %, p &lt; 0.0001), duration of mechanical ventilation, which is more than 6.48 % of the total time of PB treatment (Se = 86.67 %, Sp = 59.38 %, p &lt; 0.046).

Identifying Rare Genetic Determinants for Improved Polygenic Risk Prediction of Bone Mineral Density and Fracture Risk.

Osteoporosis and fractures severely impact the elderly population. Polygenic risk scores for bone mineral density have demonstrated potential clinical utility. However, the value of rare genetic determinants in risk prediction has not been assessed. With whole-exome sequencing data from 436,824 UK Biobank participants, we assigned White British ancestry individuals into a training data set (n = 317,434) and a test data set (n = 74,825). In the training data set, we developed a common variant-based polygenic risk score for heel ultrasound speed of sound (SOS). Next, we performed burden testing to identify genes harboring rare determinants of bone mineral density, targeting influential rare variants with predicted high deleteriousness. We constructed a genetic risk score, called ggSOS, to incorporate influential rare variants in significant gene burden masks into the common variant-based polygenic risk score. We assessed the predictive performance of ggSOS in the White British test data set, as well as in populations of non-White British European (n = 18,885), African (n = 7165), East Asian (n = 2236), South Asian (n = 9829), and other admixed (n = 1481) ancestries. Twelve genes in pivotal regulatory pathways of bone homeostasis harbored influential rare variants associated with SOS (p < 5.5 × 10-7 ), including AHNAK, BMP5, CYP19A1, FAM20A, FBXW5, KDM5B, KREMEN1, LGR4, LRP5, SMAD6, SOST, and WNT1. Among 4013 (5.4%) individuals in the test data set carrying these variants, a one standard deviation decrease in ggSOS was associated with 1.35-fold (95% confidence interval [CI] 1.16-1.57) increased hazard of major osteoporotic fracture. However, compared with a common variant-based polygenic risk score (C-index = 0.641), ggSOS had only marginally improved prediction accuracy in identifying at-risk individuals (C-index = 0.644), with overlapping confidence intervals. Similarly, ggSOS did not demonstrate substantially improved predictive performance in non-European ancestry populations. In summary, modeling the effects of rare genetic determinants may assist polygenic prediction of fracture risk among carriers of influential rare variants. Nonetheless, improved clinical utility is not guaranteed for population-level risk screening. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Ultrasonic Sound Speed Estimation for Liver Fat Quantification: A Review by the AIUM-RSNA QIBA Pulse-Echo Quantitative Ultrasound Initiative.

Non-alcoholic fatty liver disease (NAFLD) is a significant cause of diffuse liver disease, morbidity and mortality worldwide. Early and accurate diagnosis of NALFD is critical to identify patients at risk of disease progression. Liver biopsy is the current gold standard for diagnosis and prognosis. However, a non-invasive diagnostic tool is desired because of the high cost and risk of complications of tissue sampling. Medical ultrasound is a safe, inexpensive and widely available imaging tool for diagnosing NAFLD. Emerging sonographic tools to quantitatively estimate hepatic fat fraction, such as tissue sound speed estimation, are likely to improve diagnostic accuracy, precision and reproducibility compared with existing qualitative and semi-quantitative techniques. Various pulse-echo ultrasound speed of sound estimation methodologies have been investigated, and some have been recently commercialized. We review state-of-the-art in vivo speed of sound estimation techniques, including their advantages, limitations, technical sources of variability, biological confounders and existing commercial implementations. We report the expected range of hepatic speed of sound as a function of liver steatosis and fibrosis that may be encountered in clinical practice. Ongoing efforts seek to quantify sound speed measurement accuracy and precision to inform threshold development around meaningful differences in fat fraction and between sequential measurements.

Demonstration of the feasibility and practical value of direct acoustic measurements in liquid metals

The temperature dependences of ultrasound absorption and propagation speed in simple semimetals, semiconductors, and semiconductor compounds have been studied in this article. Experimental and theoretical results testify to the microheterogeneity of semimetals and semiconductor melts. Generalization and analysis of experimental data on the absorption and propagation speed of ultrasound in melts based on D.I. Mendeleev periodic law clearly indicate the presence of micro-groups of atoms (clusters) in them, microheterogenizing melts of semimetals and semiconductors. The urgency of this problem is predetermined by the problem of the liquid state of matter. The dependence of ultrasound absorption and propagation speed on temperature is measured using several groups of samples in paper, each group is heated to a different temperature. It is proved that melts have clustered in their atomic matrix, and so melts with semiconductor properties are micro-inhomogeneous. These results are needed to scale melt sonication to an industrial scale and are needed to provide valuable new insights into temperature dependencies of ultrasound absorption.

Ultrasound Shear Wave Speeds Following Hamstring Strain Injury &amp; Return To Sport

Ultrasound Shear Wave Speeds Following Hamstring Strain Injury &amp; Return To Sport

Dynamics of changes in the velocity of ultrasound propagation in the bone tissue of premature children according to the data of ultrasound densitometry

All premature babies lack the intrauterine phase of active mineralization of the bones, osteogenesis changes, speed of ultrasound propagation in bone tissue changes. Aim. The purpose of the article was to determine osteopenia in premature babies (PB) based on ultrasound densitometry at birth and during the period of intensive care. Materials and methods. 70 premature babies and 20 full-term newborns were studied. The authors determined the bone ultrasound speed (SOS, m/s) and its comparative evaluation (Z-score) with the representative base of the ultrasound sonometer “Sunlight Omnisense 9000” (Israel). SOS was defined as average at Z ≥-1.0 SD, as low – at Z from -1.1 to -2.0 SD, and as significantly low – Z ≤- 2.0 SD. Results. 54.3 % of PB had osteopenia at birth: low indicators in 28.6 %, significantly low in 25.7 %. Postnatally, an increase in bone tissue deficiency of PB was observed – osteopenia with a low Z was diagnosed in 41.1 %, with a significantly low – in 37.5 % of PB. Conclusions. The number of PB with osteopenia increased 1.4 times, during the first 4 weeks of life. An increase in bone tissue deficiency was most often (p &lt; 0.05) observed among children (52.0 %) with normal / average Z-score SOS indicators. Z-score SOS indicators in children with osteopenia were stable during the first month of life. The odds ratio of having osteopenia were 3.37 times higher for those born in GA of 33 weeks or less (OR = 3.37; CI 95 % [1.25, 9.09], p &lt; 0.05), and 7.50 times higher odds of having significantly low Z-scores (OR = 7.50; CI 95 % [1.60, 34.59], p &lt; 0.05), ), and 8.15 times higher odds of having significantly low Z-scores after 1 month of life (OR = 8.15; CI 95 % [2.23; 29.70], р &lt; 0.05), than in children with greater GA. Indicators of physical development of premature newborns do not allow assessing the state of bone mineral velocity and require dynamic ultrasonic densitometry, despite the presence of correlations of SOS with indicators of the mass or length of infants depending on the gestational timing of birth.

Calcium supplementation and body mass index modify associations between prenatal phthalate exposure and perinatal bone ultrasound measures among pregnant women

Phthalates have endocrine activity that may interfere with bone health, particularly during pregnancy and the early postpartum period, when bone resorption increases. We evaluated associations between prenatal phthalate exposure and perinatal bone health among 289 mothers in the ELEMENT birth cohort in Mexico City who were randomized upon recruitment to receive 1,200 mg daily calcium supplementation or placebo throughout pregnancy. Spot urine samples at up to three timepoints during pregnancy were assayed for 9 phthalate metabolites. Bone integrity was assessed by quantitative ultrasound speed of sound (SOS) measurements of the phalange and distal radius at 3, 6, and 8 months of pregnancy and 1, 3, 7, and 12 months postpartum. Geometric means of specific gravity-corrected phthalate concentrations were used as overall measures of prenatal exposure. Linear mixed effect models estimated associations between phthalate exposure and repeated perinatal bone SOS measures, adjusting for age, pre-pregnancy body mass index (BMI), education, parity, calcium supplementation, and month of pregnancy/postpartum. Effect modification by calcium supplementation and BMI were assessed in sensitivity analyses. An interquartile range increase in MEP and MiBP increased pregnancy phalange z-scores (β: 0.11; 95%CI: 0.003, 0.31 and β: 0.15; 95%CI: 0.00,0.42, respectively). Higher concentrations of several phthalate metabolites resulted in lower SOS measures among women who received calcium supplements (compared to placebo group) but higher SOS measures among women with a BMI≥25 (compared to BMI<25). These results suggest that phthalate exposure may interfere with bone remodeling during pregnancy, and that consideration of effect modifiers is paramount to fully understand the effects of environmental exposures on bone health.

Short-termed changes in quantitative ultrasound estimated bone density among young men in an 18-weeks follow-up during their basic training for the Swiss Armed Forces.

Quantitative Ultrasound (QUS) methods have been widely used to assess estimated bone density. This study aimed to assess changes in estimated bone density in association with changes in body composition, physical activity, and anthropometry. We examined changes in anthropometry, body composition, and physical activity associated with changes in estimated bone mineral density (measured using quantitative ultrasound with a heel ultrasound device indicating broadband ultrasound attenuation BUA and speed of sound SOS) in a follow-up sample of n = 73 young men at the beginning and again 18 weeks later at the end of basic military training. At the end of the basic training, the subjects were on average significantly heavier (+1.0%), slightly taller (+0.5%) and had a higher fat mass (+6.6%) and grip strength (+8.6%). A significant decrease in mean physical activity (-49.5%) and mean estimated bone density calculated with BUA (-7.5%) was observed in the paired t-test. The results of the multivariable linear regressions (backward selection) show that changes in skeletal muscle mass (delta = 2nd measurement minus 1st measurement) have negative and body weight (delta) have positive association with the speed of sound SOS (delta), while fat mass (delta) and physical activity (delta) had the strongest negative associations with estimated bone mineral density (delta). In particular, we found a negative association between fat mass (delta) and estimated bone mineral density (delta, estimated with BUA). Our study suggests that estimated bone density from the calcaneus can change within a few months even in young and mostly healthy individuals, depending upon physical activity levels and other co-factors. Further studies including other troop types as control groups as well as on women should follow in order to investigate this public health relevant topic in more depth. To what extent the estimated bone density measurement with quantitative ultrasound is clinically relevant needs to be investigated in further studies.

Dynamic Speed of Sound Adaptive Transmission-Reflection Ultrasound Computed Tomography.

Ultrasound computed tomography (USCT) can visualize a target with multiple imaging contrasts, which were demonstrated individually previously. Here, to improve the imaging quality, the dynamic speed of sound (SoS) map derived from the transmission USCT will be adapted for the correction of the acoustic speed variation in the reflection USCT. The variable SoS map was firstly restored via the optimized simultaneous algebraic reconstruction technique with the time of flights selected from the transmitted ultrasonic signals. Then, the multi-stencils fast marching method was used to calculate the delay time from each element to the grids in the imaging field of view. Finally, the delay time in conventional constant-speed-assumed delay and sum (DAS) beamforming would be replaced by the practical computed delay time to achieve higher delay accuracy in the reflection USCT. The results from the numerical, phantom, and in vivo experiments show that our approach enables multi-modality imaging, accurate target localization, and precise boundary detection with the full-view fast imaging performance. The proposed method and its implementation are of great value for accurate, fast, and multi-modality USCT imaging, particularly suitable for highly acoustic heterogeneous medium.

Influence of Short Carbon Fibers on the Properties of Autoclaved Fiber Cement in Standard Fire Environment.

In case of a fire, the flame can spread from the building through the outer openings to the outside. In such cases, the fire temperature thermal effect determines the façade fibrocement tile thermal destruction, while the flammable thermo-insulating systems used for building energy effectiveness ensures it sets on fire. The spread of such a fire becomes uncontrollable and raises an immediate danger to the people inside the building, while such event dynamics delay and make it harder to put out the fire. Extra additive usage in façade fibrocement tiles can raise its resistance to fire temperature effect. Carbon fiber is widely known as a material resistant to the high temperature destructive effect. An investigation was conducted on the influence that carbon fiber has on the properties of autoclaved fiber cement samples. The autoclaved fiber cement samples were made from the raw materials, typical for façade fiber cement plates, produced in an industrial way (using the same proportions). In the samples, carbon fiber was used instead of mix cellulose fiber in 0.5%, 0.75%, 1% proportions. After completing the density research, it was determined that the carbon fiber effect had no general effect on the sample density. Ultrasound speed spreading research showed that the carbon fiber insignificantly makes sample structure denser; however, after the fire temperature effect, sample structure is less dense when using carbon fiber. The results of both these investigations could be within the margin of error. Insignificant sample structure density rise was confirmed with water absorption research, which during the 1% carbon fiber usage case was lower by 4.3%. It was found that up to 1% carbon fiber usage instead of mix cellulose fiber creates a dense structure of autoclaved fiber cement samples, and the carbon fiber in the microstructure influences the mechanical properties of the autoclaved fiber cement samples. After using carbon fiber in ambient temperature, the sample compressive strength and bending strength increased. However, the results of mechanical properties were completely different after experiencing fire temperature effect. Scanning electron microscopy research showed that the bond between the carbon fiber and the cement matrix was not resistant to high temperature effect, due to which the structure of the samples with carbon fiber weakened. Research showed that carbon fiber lowers the mechanical properties of the autoclaved fiber cement samples after high temperature effect. After analyzing the density, ultrasound speed spreading, water absorption, microstructure and macrostructure, compressive strength, and bending strength, the authors determined the main CF usage for AFK dependencies: 1. CF usage up to 1% replacing MCF makes the AFK structure more dense up to 1.5%, and lowers the water absorption up to 4.3%; 2. CF incorporates itself densely into the AFC microstructure; 3. CF usage up to replacing MCF improves the AFK strength properties up to until the fire temperature effect. Compression strength increases up 7.3% while bending strength increases up to 14.9%. 4. AFK hydrate amount on CF surface is lower than on MCF; 5. Fire temperature effect on AFK with CF causes dehydration by removing water vapor from the microstructure, resulting in a lot of microcracks due to stress; 6. The CF and cement matrix contact zone is not resistant to fire temperature effect. SEM experiments were used to determine the CF "self-removing" effect; 7. Due to complex changes happening in the AFK during fire temperature effect, CF usage does not improve strength properties in the microstructure. Compression strength decreases to 66.7% while bending strength decreases to 20% when compared with E samples.

All-optical, non-contact, local measurement of both Young’s modulus and Poisson’s ratio in metals using a combination of Rayleigh and leaky surface acoustic waves

In non-destructive evaluation (NDE), measuring ultrasound (US) longitudinal and shear wave speeds is the main method to determine two independent mechanical moduli (Young’s modulus and Poisson’s ratio). Most US techniques use time-of-flight measurements. However, when the local sample thickness is unknown or the sample geometry is complex, bulk-wave propagation speeds cannot be accurately defined. Here we show that a properly shaped beam of nanosecond laser pulses can be used to efficiently excite (without material ablation) two types of surface acoustic waves. In addition to a conventional surface, or Rayleigh, wave, a leaky surface wave (LSAW) can be launched in the near field of the excitation region. We present the theoretical background, numerical simulations, and experimental results clearly showing that both elastic constants can be reconstructed locally by tracking Rayleigh and LSAW waves. Spatially resolved elastic properties can be obtained using local values of wave speeds obtained by sample scanning. Non-contact optical detection of propagating waves at the sample surface, in which a fiber-optic Sagnac interferometer was used, is a key piece of the method. It does not require acoustic coupling and allows remote measurements in the near field of the laser source with micron-scale resolution.