The Influence of a 14-Week Infantry Commanders Courses on the Achilles Tendon and Patellar Tendon Structure

ABSTRACT Introduction Alternated tendon structure may raise stress to the musculoskeletal structures and may increase the potential for overuse injury. Screening the tendon structure of soldiers pre- and post-participation in a strenuous combat course is essential. The aim of the present study was to investigate the influence of a 14-week infantry commanders courses on the Achilles tendon (AT) structure and patellar tendon (PT) structure in combat soldiers. Materials and Methods Ninety-eight participants from an infantry commanders course were screened pre- and post-course for the AT and PT structures, using ultrasonographic tissue characterizaton (UTC) imaging to capture a 3D structure of four echo-type fibers (I-IV). Results In both tendons, the mean relative frequency of echo-type I fibers significantly decreased from pre- to post-testing, with a significant increase in the relative frequency of echo-types II, III, and IV fibers. In the AT, 60.2% of the subjects showed positive differences (between pre- and post-testing in the echo-type III + IV fiber (“worsened” tendon structure), whereas in the PT, 92.2% of the subject showed an increased frequency. No significant correlation (r = 0.108; P = .324) was found between the differences of echo-type III + IV fibers of the AT and that of the PT. Conclusions Loads to the musculoskeletal structures along the combat course increased the mean relative frequency of the “reduced” echo-type fibers (III + IV) in both the AT structure and the PT structure. Yet, whereas in the AT around 40% of the soldiers showed an improved tendon structure along the course, in the PT less than 10% of the soldiers showed that improvement. Soldiers and commanders should be aware of the different influence of the loading exercises along the course on the AT and on the PT structure, as “reduced” tendons structure might put the soldiers at higher risk for injury in the future.

Semantic analysis of fluctuations of a radar pack for identification of air objects

A method for semantic analysis of amplitude fluctuations of the radar pack to identify air objects in surveillance radars has been developed and implemented in software. This method is based on the determination of semantic components at the stage of formation and analysis of the symbolic model of a burst of impulse signals from mobile aircraft. Signal information is described by the predicate function of the process knowledge of the formation and analysis of the symbolic model of a burst of impulse signals from mobile aircraft such as an airplane, helicopter, UAV, and from atmospheric inhomogeneities of the angel-echo type. As a result of semantic analysis of the amplitude fluctuations, classification distinguishing attributes of fluctuations from interfering reflections and air objects are obtained. The semantic components of the decision-making algorithm, which are similar to decision-making algorithms by the operator, are investigated. In the developed algorithm, the signal information is described by a predicate function on the set of amplitudes of burst pulses exceeding a certain threshold value. Identification of the types of fluctuations is carried out by solving the developed equations of predicate operations. Based on these equations, a functional diagram of automatic determination of the fluctuation types is synthesized. The verification of the developed method was carried out on real data obtained on a survey centimeter-band radar (pulse duration 1 μs, sounding frequency 365 Hz, survey period 10 s). Based on these data, types of characteristic packs of radar signals are simulated. According to the results of the experiments, they were all correctly identified.

Age and gender dependence of liver diffusion parameters and the evidence of intravoxel incoherent motion modelling of perfusion component is constrained by diffusion component

ObjectivesTo establish reference values for middle aged subjects and investigate age and gender dependence of liver diffusion MRI parameters.MethodsThe IVIM type of liver diffusion scan was based on a single-shot spin-echo type echo-planar sequence using a 1.5-T magnet with 16 b-values. DDVD (diffusion-derived vessel density) was the signal difference between b=0 and b=2 s/mm2 images after removing visible vessels. IVIM analysis was performed with full-fitting and segmented-fitting, and with threshold b-value of 60 or 200 s/mm2, and fitting started from b=2 s/mm2. 32 men (age range: 25-71 years) and 26 men (age: 22-69 years) had DDVD and IVIM analysis respectively, while 36 women (age: 20-71 years) had DDVD and IVIM analysis.ResultsDDVD had an age-related reduction noted for women. IVIM results of full fitting had good agreement with segmented fitting with threshold b of 60 s/mm2 results, but less so with results of threshold b of 200 s/mm2. As age increases, female subjects’ Dslow measure had significant reduction, and PF and Dfast measure had significant increase. For the age group of 40-55 years, DDVD, Dslow, PF, and Dfast were 12.27±3.90, 1.072±0.067 (10−3mm2/s), 0.141±0.025, 61.0±14.0 (10−3mm2/s), and 13.4±3.6, 1.069±0.074 mm2/s, 0.119±0.014, 57.1±13.2 mm2/s, for men and women, respectively.ConclusionDDVD measure suggest that aging may be associated with reduction in liver perfusion. Lower Dslow measurement can lead to artificial higher PF and Dfast measurement, providing the evidence of IVIM modeling of perfusion component is constrained by diffusion component.

Ultrasound Tissue Characterization (UTC) of the Achilles Tendon in Pre- and Post-Pubertal Dancers

This study examined whether maturation status, body physique, and the impact of training are related to the development of Achilles tendon structure in young dancers. Seventy-one pre- and post-menarche dancers (12 to 15 years of age) were recruited. The Achilles tendon of each dancer was examined via ultrasonography tissue characterization (UTC) imaging. The cross-sectional area (CSA) and the fibrillar structure (echo types I to IV) were measured. The participants were screened for anthropometric parameters (weight, height, and leg length) with body mass index (BMI) and BMI percentile calculated; for hours and impact of training; for Tanner pubertal maturation; and for pain in their Achilles tendon (VAS scale). In addition, age and age at onset of menarche were documented. Tendon structure was found to differ between pre- and post-menarche dancers. Post-menarche dancers had a significantly lower percentage of echo type I fibers and a significantly higher percentage of echo type II, III, and IV fibers, with a greater CSA compared to pre-menarche dancers. The tendon structure was found to be correlated with BMI percentile, but no correlations were found with chronologic age or the impact of dance training. Furthermore, ANCOVA showed that BMI had a statistically significant effect on fiber types II and III (p < 0.005) and that the effect of menarche was significant, meaning that pre-menarche dancers had a lower BMI compared with those who were post-menarche. It is concluded that pre- and post-menarche dancers had developed different patterns of Achilles tendon fiber structure. Body mass index was found to be the most significant factor influencing the different tendon structures in young pubertal dancers.

Running a Marathon—Its Influence on Achilles Tendon Structure

Context Several studies have been conducted to better understand the effect of load on the Achilles tendon structure. However, the effect of a high cumulative load consisting of repetitive cyclic movements, such as those that occur during the running of a marathon, on Achilles tendon structure is not yet clear. Clinicians, coaches, and athletes will benefit from knowledge about the effects of a marathon on the structure of the Achilles tendon. Objective To investigate the short-term response of the Achilles tendon structure to running a marathon. Design Case series (prospective). Setting Sports medicine centers. Patients or Other Participants Ten male nonelite runners who ran in a marathon. Main Outcomes Measure(s) Tendon structure was assessed before and 2 and 7 days after a marathon using ultrasound tissue characterization (UTC), an imaging tool that quantifies tendon organization in 4 echo types (I–IV). Echo type I represents the most stable echo pattern, and echo type IV, the least stable. Results At 7 days postmarathon, both the insertional and midportion structure changed significantly. At both sites, the percentage of echo type II increased (insertion P &lt; .01; midportion P = .02) and the percentages of echo types III and IV decreased (type III: insertion P = .01; midportion P = .02; type IV: insertion P = .01; midportion P &lt; .01). Additionally, at the insertion, the percentage of echo type I decreased (P &lt; .01). Conclusions We observed the effects of running a marathon on the Achilles tendon structure 7 days after the event. Running the marathon combined with the activity performed shortly thereafter might have caused the changes in tendon structure. This result emphasizes the importance of sufficient recovery time after running a marathon to prevent overuse injuries.

Ultrasound tissue characterization - to measure matrix integrity and to quantify regenerative processes in equine tendons and ligaments

Tendon injuries often threaten the athletic career of performance horses. There may be single overloading but frequently the injury is the result of a gradual matrix degradation, initially without clinical signs, which may lead to impaired regenerative capacity. Another complicating factor is the lack of uniform pathology; frequently multiple stages of matrix integrity can be found and, therefore, there is no cure-all treatment. Ultrasound Tissue Characterization (UTC) is designed for tomographic visualization and quantification of 3-D matrix integrity. UTC is based on standardized compilation of ultrasound-data by means of an ultrasound probe that moves automatically along the tendon’s long axis, collecting transverse images every 0.2 mm, generating a 3-D volume. UTC-algorithms can discriminate 4 different echo-types, related to size and integrity of structures in the matrix (van Schie et al. 2003): Echo-type I, generated by intact and aligned fascicles with axial diameter ≥ spatial resolution. Echo-type II, generated by discontinuous, waving and/or swollen fascicles with axial diameter ≥ spatial resolution. Echo-type III, generated by a matrix mainly consisting of fibrils with axial diameter < spatial resolution. Echo-type IV, generated by a mainly amorphous matrix and fluid. Fundamental research with isolated tendons revealed that the ratios of these 4 echo-types are highly correlated with tendon matrix integrity, showing the discriminative power of UTC for tissue characterization (van Schie et al. 2009).Normal superficial digital flexor tendons in young mature horses are characterized by 80-90% type I, 10-15% type II and barely any type III and/or IV echoes. Loss of integrity is characterized by significant changes like decrease of type I, increase of type II (remodeling or inferior repair) and increase of type III (fibrillar) and/or IV (amorphous). Intra- and inter- observer reliability appeared to have intra-class correlations (ICC) ranging 0.92-0.98, indicative for excellent reproducibility. Clinical research revealed that UTC is sensitive and reliable to: • Monitor load-effects and detect matrix degradation (Plevin et al. 2019). Stage lesions for selection of appropriate intervention. • Quantify regenerative processes for objective evaluation of therapy and guided rehabilitation (Bosch et al. 2011).

Isotopically enhanced triple-quantum-dot qubit

Like modern microprocessors today, future processors of quantum information may be implemented using all-electrical control of silicon-based devices. A semiconductor spin qubit may be controlled without the use of magnetic fields by using three electrons in three tunnel-coupled quantum dots. Triple dots have previously been implemented in GaAs, but this material suffers from intrinsic nuclear magnetic noise. Reduction of this noise is possible by fabricating devices using isotopically purified silicon. We demonstrate universal coherent control of a triple-quantum-dot qubit implemented in an isotopically enhanced Si/SiGe heterostructure. Composite pulses are used to implement spin-echo type sequences, and differential charge sensing enables single-shot state readout. These experiments demonstrate sufficient control with sufficiently low noise to enable the long pulse sequences required for exchange-only two-qubit logic and randomized benchmarking.