Multi-stage coherent beam combination of semiconductor optical amplifiers in ready-made fiber couplers.

We report on multi-stage coherent beam combination (CBC) of continuous-wave (CW) outputs from semiconductor optical amplifiers (SOAs) in ready-made fiber couplers. The first CBC stage combines two 120-mW outputs from SOAs seeded by an extended-cavity diode laser (ECDL) at 1458 nm in a 2×2 50%:50% fiber coupler. Two beams generated by two such CBC setups are then combined in the second stage. By concatenating three stages we obtained an output power of 723 mW at 1458 nm from eight SOAs with a total combining efficiency of 75.3%. Stable power generation without interrupts nor degradation over three days was successfully implemented using a simple low-bandwidth servo system. An averaged single-stage combining efficiency of 89.5% deduced from seven CBC setups constituting the three-stage CBC is used to estimate scaling to further stages. As a practical application the output is used to second harmonic generation (SHG) in a nonlinear crystal to achieve an output power of 239 mW at 729 nm.

USV-Observed Turbulent Heat Flux Induced by Late Spring Cold Dry Air Incursion over Sub-Mesoscale Warm Regions off Sanriku, Japan.

We performed oceanic and atmospheric observations in the region off the Sanriku coast, Japan, from May 11 to 5 July 2022, using a wave-propelled unmanned surface vehicle, a Wave Glider (WG). Despite the severe weather conditions of atmospheric low-pressure system crossings, we successfully measured wind, air temperature, humidity, and sea surface temperature over the course of 55 days to calculate the turbulent heat flux. The WG observed that the atmosphere became more humid due to the southerly wind along the northwestern rim of the North Pacific subtropical high. The warm Kuroshio water expanded to the southeast of Hokkaido as a result of the northward shedding of an anticyclonic mesoscale (~100 km) eddy, called a warm-core ring, from the Kuroshio Extension. The WG traversed smaller (sub-mesoscale) water regions that were warmer and saltier than the surrounding Kuroshio water. The observations indicate that cold, dry air masses advected by northerly winds following the passage of atmospheric low-pressure systems generate a substantial upward turbulent heat flux over sub-mesoscale warm water regions, contrasting to no heat flux in the surrounding Kuroshio water region.

[Improvement of Brain Contrast Using Spin Echo T1-weighted Image at 3 T MRI].

Brain T1-weighted images using spin echo (SE) sequence has poor contrast at 3.0 Tesla magnetic resonance imaging (3.0 T MRI) systems from the influence of crosstalk and magnetized transfer (MT) effect, and prolongation of the T1 value. Therefore, improving of scan parameters has been reported such as excitation flip angle (FA) and interleave data acquisition. The purpose of this study was to show the effects of alterations of presaturation pulse amplitude and chemical shift selective (CHESS) pulse amplitude. Gray-to-white matter contrast increased with decreasing amplitude of presaturation pulse in whole brain imaging. Presaturation and CHESS pulse consist of radio frequency pulse. Therefore, both pulses have a similar effect on MT pulse. Manual alteration of presaturation pulse amplitude for each scan lacks versatility on clinical use. However, decreasing amplitude of presaturation pulse is equal to decreasing thickness of presaturation pulse. About CHESS pulse, it requires no manual alteration for each scan. For example, switching fat suppression mode from strong to weak increase T1 contrast. Our study demonstrated that using not only low excitation FA and interleave date acquisition but also low amplitude of presaturation and CHESS pulse increase the contrast in T1 SE brain scans at 3.0 T MRI.

An uncertainty metric to evaluate deformation vector fields for dose accumulation in radiotherapy.

BACKGROUND AND PURPOSE: In adaptive radiotherapy, deformable image registration (DIR) is used to propagate delineations of tumors and organs into a new therapy plan and to calculate the accumulated total dose. Many DIR accuracy metrics have been proposed. An alternative proposed here could be a local uncertainty (LU) metric for DIR results. MATERIALS AND METHODS: The LU represented the uncertainty of each DIR position and was focused on deformation evaluation in uniformly-dense regions. Four cases demonstrated LU calculations: two head and neck cancer cases, a lung cancer case, and a prostate cancer case. Each underwent two CT examinations for radiotherapy planning. RESULTS: LU maps were calculated from each DIR of the clinical cases. Reduced fat regions had LUs of 4.6 ±â€¯0.9 mm, 4.8 ±â€¯1.0 mm, and 4.5 ±â€¯0.7 mm, while the shrunken left parotid gland had a LU of 4.1 ±â€¯0.8 mm and the shrunken lung tumor had a LU of 3.7 ±â€¯0.7 mm. The bowels in the pelvic region had a LU of 10.2 ±â€¯3.7 mm. LU histograms for the cases were similar and 99% of the voxels had a LU < 3 mm. CONCLUSIONS: LU is a new uncertainty metric for DIR that was demonstrated for clinical cases. It had a tolerance of <3 mm.

Efficacy of distortion correction on diffusion imaging: comparison of FSL eddy and eddy_correct using 30 and 60 directions diffusion encoding.

Diffusion imaging is a unique noninvasive tool to detect brain white matter trajectory and integrity in vivo. However, this technique suffers from spatial distortion and signal pileup or dropout originating from local susceptibility gradients and eddy currents. Although there are several methods to mitigate these problems, most techniques can be applicable either to susceptibility or eddy-current induced distortion alone with a few exceptions. The present study compared the correction efficiency of FSL tools, "eddy_correct" and the combination of "eddy" and "topup" in terms of diffusion-derived fractional anisotropy (FA). The brain diffusion images were acquired from 10 healthy subjects using 30 and 60 directions encoding schemes based on the electrostatic repulsive forces. For the 30 directions encoding, 2 sets of diffusion images were acquired with the same parameters, except for the phase-encode blips which had opposing polarities along the anteroposterior direction. For the 60 directions encoding, non-diffusion-weighted and diffusion-weighted images were obtained with forward phase-encoding blips and non-diffusion-weighted images with the same parameter, except for the phase-encode blips, which had opposing polarities. FA images without and with distortion correction were compared in a voxel-wise manner with tract-based spatial statistics. We showed that images corrected with eddy and topup possessed higher FA values than images uncorrected and corrected with eddy_correct with trilinear (FSL default setting) or spline interpolation in most white matter skeletons, using both encoding schemes. Furthermore, the 60 directions encoding scheme was superior as measured by increased FA values to the 30 directions encoding scheme, despite comparable acquisition time. This study supports the combination of eddy and topup as a superior correction tool in diffusion imaging rather than the eddy_correct tool, especially with trilinear interpolation, using 60 directions encoding scheme.

Comparison of the effects of flexion and extension of the thumb and fingers on the position and cross-sectional area of the median nerve.

OBJECTIVE: To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area. METHODS: Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied. RESULTS: Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2 ± 0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2 ± 0.9 and 3.1 ± 1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0 ± 0.8 mm) and little finger (1.2 ± 0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5 ± 1.1 mm(2)). CONCLUSIONS: Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.

Cardiovascular responses to static muscle contraction in patients with brachial plexus injury treated with intercostal nerve transfer.

Pressor response is carried in afferent fibers of somatic nerves to increase blood pressure (BP) and heart rate (HR) during static exercise in humans. However, there is no information that peripheral responses restore muscle contraction with nerve transfer operation. In this study, we aimed to assess isometric exercise-induced pressor responses in patients with brachial plexus injury (BPI) after intercostal nerve transfer (ICNT) to restore elbow flexor muscles. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR during 2-min sustained isometric muscle contraction of elbow flexors at 20% and 35% of maximal voluntary contraction (MVC) on the unaffected side and the ICNT side, were measured in seven subjects with BPI treated with ICNT. SBP, DBP, and HR during 2-min sustained isometric muscle contraction of elbow flexors at 20% of MVC on the unaffected side were similar to those recorded before and after the exercise. However, the same variables increased significantly (p<0.001) during a similar type of exercise at 35% MVC on the unaffected side. On the ICNT side, no significant differences were noted in elbow flexors at 20% and 35% MVC. Isometric static exercise at 35% of MVC did not induce pressor and HR changes on the ICNT side. The difference in the responses between the two sides could have been caused by incomplete recovery of afferent nerve function following nerve repair, despite the restoration of efferent nerve function. Alternatively, the HR and BP responses to static contraction may depend upon the active muscle mass.

CLP36 interacts with palladin in dorsal root ganglion neurons.

CLP36, a member of the alpha-actinin-associated LIM protein (ALP)/enigma protein family, plays a role in neurite outgrowth in the peripheral nervous system. However, the underlying molecular mechanisms are not known. In this study, we performed yeast two-hybrid screening of an E18 mouse whole-body cDNA library with CLP36 as the bait and isolated palladin as a CLP36-binding protein. Palladin is an actin-binding protein and it was shown to have a role in the extension of cortical neurons. A coimmunoprecipitation study showed that CLP36 and palladin formed a complex in the dorsal root ganglion (DRG). In addition, CLP36 and palladin were colocalized in the neurites and cell bodies of primary DRG neurons. Furthermore, sciatic nerve transection increased the expression of both CLP36 and palladin mRNAs in DRG neurons, with the increase in CLP36 mRNA being more prominent. This implies that CLP36 has a more specific role in nerve regeneration than palladin. Our results suggest that CLP36 may interact with palladin to influence neurite outgrowth during sciatic nerve regeneration.

A longitudinal analysis of urinary biochemical markers and bone mineral density in STR/Ort mice as a model of spontaneous osteoarthritis.

OBJECTIVE: To investigate the longitudinal changes both in the urinary concentrations of biochemical markers and in bone mineral density (BMD) during disease progression in the STR/Ort mouse model of osteoarthritis (OA). METHODS: Male STR/Ort mice were studied, with CBA mice used as nonarthritic controls. Radiographic evaluation and grading of the knee and measurements of urinary C-terminal crosslinking telopeptide of type II collagen (CTX-II), pyridinoline (Pyr), and deoxypyridinoline were performed between 8 weeks and 40 weeks of age. The BMD of the femoral shaft was measured from 20 weeks to 40 weeks of age and adjusted for body weight. Histologic evaluation and grading were performed at 40 weeks of age. STR/Ort mice were divided into 2 subgroups (STR OA and STR non-OA) based on histologic grading. RESULTS: No significant differences between STR/Ort and CBA mice were observed for any biochemical marker or BMD at any time point. Urinary CTX-II levels and BMD in the STR OA subgroup were higher than those in the STR non-OA subgroup before radiographic changes of OA were apparent. Higher urinary Pyr levels in the STR OA subgroup were observed at the advanced stage of OA. CONCLUSION: Urinary CTX-II could be a useful marker in the early diagnosis and predicting the progression of OA, and urinary Pyr may be a potential marker to assess the severity of OA at an advanced stage. An increase in BMD prior to the establishment of radiographic OA may be related to the induction of OA.

Patellar impingement by synovial cord following anterior cruciate ligament reconstruction.

We found a cordlike structure (synovial cord) in the patellofemoral joint causing patellar impingement in a 45-year-old man after anterior cruciate ligament (ACL) reconstruction. Arthroscopic examination revealed that a cylindrical cordlike soft tissue with a smooth surface extended between the medial and lateral capsule of the patellofemoral joint. The tissue histologically consisted of dense collagen fibers in parallel bundles covered with thin layers of synovial tissue; in addition, there was a proliferation of small vessel patches surrounded by hemosiderin-laden macrophages, which indicated bleeding episodes due to impingement in the patellofemoral joint. To our knowledge, this is the first case report of a synovial cord in the patellofemoral joint causing patellar impingement following ACL reconstruction.

Quantitative evaluation of bone resorption activity of osteoclast-like cells by measuring calcium phosphate resorbing area using incubator-facilitated and video-enhanced microscopy.

Quantitative evaluation of the ability of bone resorption activity in live osteoclast-like cells (OCLs) has not yet been reported on. In this study, we observed the sequential morphological change of OCLs and measured the resorbing calcium phosphate (CP) area made by OCLs alone and with the addition of elcatonin utilizing incubator facilitated video-enhanced microscopy. OCLs, which were obtained from a coculture of ddy-mouse osteoblastic cells and bone marrow cells, were cultured on CP-coated quartz cover slips. The CP-free area increased constantly in the OCLs alone, whereas it did not increase after the addition of elcatonin. This study showed that analysis of the resorbed areas under the OCL body using this method enables the sequential quantitative evaluation of the bone resorption activity and the effect of several therapeutic agents on bone resorption in vitro.

Lateral radiographic study of the tibial sagital insertions of the anteromedial and posterolateral bundles of human anterior cruciate ligament.

Recently, the femoral attachments of anteromedial and posterolateral bundles of anterior cruciate ligament (ACL) have been extensively discussed, however, few publications have mentioned radiographic measurements of the tibial insertions of two bundles. The aim of this study is to determine the radiographic measurements of the tibial sagital insertions for anteromedial (AM) and posterolateral (PL) bundles of ACL. Thirty-one cadaveric proximal tibias were used. After identification of the AM and PL bundles insertion sites on the tibia, the insertion center and the other anatomic landmarks were marked with a lead pin, and lateral radiographs were taken. Sagital percentage is a percentage of the location of the insertion point calculated from the anterior margin of the tibia in the anteroposterior direction. Anterior edge of ACL averaged 25.0%, center of AM averaged 34.6%, center of PL averaged 38.4%, posterior edge of ACL averaged 50.2%. This study defines the radiographic location of the tibial insertions of the anteromedial and posterolateral bundles of ACL. This contributes to more precise evaluation of anatomical double bundle ACL reconstruction surgery postoperatively.

Evaluation of team-doctor actions during football games in Japanese professional football.

There have been many studies on football (soccer) match injuries both in national leagues and international tournaments, including the World Cup. However, no previous study on the number and types of actions taken by a team-doctor during a football season has been investigated. The aim of this study is to investigate what actions and how much a team doctor acts during professional football matches in a typical season of the Japanese professional football league (J-League). Injuries were prospectively recorded by team doctors with a Japanese professional league club during the 2004 season. Data recorded by the attending doctor after each match included information relating to the injury, time of occurrence and actions taken by the doctor in response to the injuries. The activity of the doctor was graded into 6 categories (grade A to F). During the 42 official matches held throughout the 2004 season, a total of 67 doctor-actions were taken. The overall doctor-action frequency rate (DAFR) was 1.6 actions per match. This study demonstrated how the team doctor acts during an average football match, and provides some useful information for team-doctors who attend football matches.

Distribution of hydroxyapatite crystallite orientation and ultrasonic wave velocity in ring-shaped cortical bone of bovine femur.

At the nanoscopic level, bone consists of calcium phosphate, which forms incomplete hydroxyapatite (HAp) crystals. The preferred orientation of the c-axis of HAp crystallites induces anisotropy and inhomogeneity of elastic properties in bone. In this study, the effect of the preferred orientation of HAp crystallites on the spatial distribution of ultrasonic wave velocity was experimentally investigated, considering bone mineral density (BMD) and microstructure. Three ring-shaped cortical bone samples were made from a 36-month-old bovine femur. Longitudinal wave velocity was measured by a conventional ultrasonic pulse system, using self-made polyvinylidene fluoride transducers. The integrated intensity of the (0002) peak obtained using X-ray diffraction was estimated to evaluate the amount of preferred orientation. The velocity distribution pattern was similar to the distribution of integrated intensity of (0002). The effect of the preferred orientation of HAp crystallites on velocity was clearly observed in the plexiform structure, despite the fact that the BMD value was almost independent of the preferred orientation of HAp crystallites. Velocity measurement of cortical bone can reveal information about HAp crystallite orientation.

Comparison between resection arthroplasty alone and resection arthroplasty with arthrodesis of the first MTP joint for rheumatoid forefoot deformities.

It has been reported that nearly 90% of patients with rheumatoid arthritis (RA) have problems with their feet. Several methods of treating hallux valgus deformity in RA have previously been reported, including arthrodesis and joint resection, and good results have been observed with surgical procedures. In this report, we compare the clinical and radiological outcomes of resection arthroplasty alone (the first method) and resection arthroplasty with arthrodesis of the first MTP joint (the second method) for the treatment of forefoot deformities of RA patients. On clinical assessment, the American Orthopaedic Foot and Ankle Society (AOFAS) scale score significantly improved in both methods; however, the second method gave better results than the first method in relation to the footwear and alignment components. On radiographic assessment, in the first method there were no significant changes in the valgus angle (H-V angle) and the fifth metatarsal bone (M1/5) angle between preoperation and last follow-up. In contrast, these angles were decreased in the second method. One of the most important issues in the treatment of forefoot deformities in RA patients is to correct splaying foot deformity. We believe that the second method, which can correct splaying foot deformity, is currently the most reliable treatment method.

Correlation between hydroxyapatite crystallite orientation and ultrasonic wave velocities in bovine cortical bone.

The mineral component of bone is mainly composed of calcium phosphate, constituting 70% of total bone mass almost entirely in the form of hydroxyapatite (HAp) crystals. HAp crystals have a hexagonal system and uniaxial elastic anisotropy. The objective of this study was to investigate the effect of HAp crystallite preference on macroscopic elasticity. Ultrasonic longitudinal wave velocity and the orientation of HAp crystallites in bovine cortical bone are discussed, considering microstructure, density, and bone mineral density (BMD). Eighty cube samples of cortical bone were made from two bovine femurs. The orientation of HAp crystallites was evaluated by integrated intensity ratio of (0002) peak using an X-ray diffractometer. Ultrasonic longitudinal wave velocity was investigated with a conventional pulse system. The intensity ratio of HAp crystallites and velocity were measured in three orthogonal directions; most HAp crystallites aligned in the axial direction of the femurs. Our results demonstrate a linear correlation between velocity and intensity ratio in the axial direction. Significant correlation between velocity and BMD values was observed; however, the correlation disappeared if we focused on the identical type of microstructure. In conclusion, differences in microstructure type have an impact on density and BMD, which clearly affects the velocity. In addition, at the nanoscopic level, HAp crystallites aligned in the axial direction also affected the velocity and anisotropy.

Biochemical study of collagen and its crosslinks in the anterior cruciate ligament and the tissues used as a graft for reconstruction of the anterior cruciate ligament.

Among tissue grafts used for reconstruction of the anterior cruciate ligament (ACL), the pateller tendon (PT) and semitendinosus tendon (ST) are commonly used. It was thought that there were differences in the biochemical composition and process of healing between PT and ST. The aim of this study was to investigate the biochemical difference between ACL and the graft tissues used for reconstruction of the ACL. Hydroxyproline and crosslinks of collagen and elastin were measured from samples of 29 knees from cadavers preserved in formalin solutions. The results of measurements were hydroxyproline: ACL 0.522, PT 0.577, ST 0.463 (micromol/mg dry weight); pyridinoline/collagen: ACL 0.381, PT 0.272, ST 0.244 (mol/mol); and pentosidine/collagen: ACL 0.0434, PT 0.0558, ST 0.0799 (mol/mol). The biochemical properties of PT was not so different from ST. Pentosidine also was measured in the present study to aid in the comparison of the ligament and tendons of the knee joint.

Sequential changes of bone metabolism in normal and delayed union of the spine.

UNLABELLED: Time-dependent changes in bone markers in delayed or nonunion of vertebral fracture were compared with those of normal union. Thirty-three patients with a fresh vertebral fracture were enrolled. Urinary Type I collagen C-terminal telopeptide, pyridinoline, deoxypyridinoline, serum C-terminal telopeptide, and N-midportion of osteocalcin (OC(N-mid)) were determined at the time of hospital admission (within 24 hours after the fracture event in all cases) and at 2, 4, 12, 24, and 48 weeks thereafter. Subjects were divided into two groups according to the results of MR images taken 48 weeks after fracture. Twenty-four were normally united (Group N) and nine had delayed or nonunion (Group D) of the spine. No differences between values of bone resorption markers in Group N and Group D were observed at any time. Serum OC(N-mid) in Group N started to increase at 2 weeks and reached the peak value at 24 weeks (180%); however, serum OC(N-mid) in Group D increased at most 120% from baseline to 4 weeks. Values of serum OC(N-mid) in Group N were higher at 24 and 48 weeks than those in Group D. Impairment of fracture healing was strongly associated with a deficit in the increase of osteocalcin in the later stage of fracture repair. LEVEL OF EVIDENCE: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Etanercept reduces the oxidative stress marker levels in patients with rheumatoid arthritis.

This study was performed to evaluate the effects of the TNF-alpha inhibitor etanercept on oxidation stress markers representing DNA damage, lipid peroxidation, and protein glycosylation. Twenty-two rheumatoid arthritis (RA) patients underwent etanercept treatment. The levels of serum total, urinary total, and urinary free pentosidine, which is an advanced glycation end-product (AGE), of urinary N(epsilon)-hexanoyl lysine (N(epsilon)-HEL), and of 8-hydroxy-deoxy guanosine (8-OHdG) were measured at baseline and at 3 and 6 months after the initial treatment with etanercept. Serum total and urinary total pentosidine levels were reduced at 6 months after the initial treatment with etanercept, and urinary free pentosidine levels were reduced at 3 and 6 months. Urinary N(epsilon)-HEL levels were also reduced at 3 and 6 months, and urinary 8-OHdG levels were reduced at 6 months. Serum total and urinary total pentosidine levels in RA patients correlated with the number of swelling joints and tender joints, and urinary total pentosidine levels correlated with the Disease Activity Score using 28 joints (DAS28). This study demonstrated that etanercept acts as a regulator against pentosidine formation, oxidative DNA damage, and lipid peroxidation in RA patients.