Delayed response in rectus abdominis muscle following a step perturbation in subjects with and without recurrent low back pain.

BACKGROUND: Delayed trunk and lower limb muscle activation is associated with balance loss and fall injuries in subjects with recurrent low back pain (LBP). PURPOSE: This study was conducted to compare differences in the onset of muscle contractions of the trunk and lower limb muscles following a treadmill-induced step perturbation between subjects with and without LBP. METHODS: Eighty-three right limb dominant individuals (43 subjects with LBP and 40 control subjects) were exposed to the perturbation (0.31 m/s velocity for 0.2 m). The electromyography (EMG) reaction times were analyzed during the first step following the perturbation. The EMG electrodes were placed on both sides of the trunk and lower limbs, including the rectus abdominis (RA), erector spinae (ES), tibialis anterior (TA), and gastrocnemius (GA) muscles. RESULTS: The group x muscle interaction was statistically significant (F = 9.44, p = 0.003). The TA muscle activation was significantly delayed compared to the RA, ES, and GA. There was a significant interaction on side x muscle (F = 4.14, p = 0.04). The RA muscles were significantly delayed on the non-dominant (t = - 3.35, p = 0.001) and dominant (t = - 2.53, p = 0.01) sides in the LBP group. CONCLUSION: The LBP group demonstrated a delayed reaction time on the RA muscles, which indicated poor trunk control relative to the lower limbs. The delayed bilateral RA muscle might indicate possible coordination problems relative to the ES and lower limb muscles, which may lead to potential fall hazards.

Quality Management System for an IoT Meteorological Sensor Network-Application to Smart Seoul Data of Things (S-DoT).

Meteorological data with a high horizontal resolution are essential for user-specific weather application services, such as flash floods, heat waves, strong winds, and road ice, in urban areas. National meteorological observation networks, such as the Automated Synoptic Observing System (ASOS) and Automated Weather System (AWS), provide accurate but low horizontal resolution data to address urban-scale weather phenomena. Many megacities are constructing their own Internet of Things (IoT) sensor networks to overcome this limitation. This study investigated the status of the smart Seoul data of things (S-DoT) network and the spatial distribution of temperature on heatwave and coldwave event days. The temperature at above 90% of S-DoT stations was higher than that at the ASOS station, mainly because of different surface covers and surrounding local climate zones. A quality management system for an S-DoT meteorological sensor network (QMS-SDM) comprising pre-processing, basic quality control, extended quality control, and data reconstruction using spatial gap-filling was developed. The upper threshold temperatures for the climate range test were set higher than those adopted by the ASOS. A 10-digit flag for each data point was defined to discriminate between normal, doubtful, and erroneous data. Missing data at a single station were imputed using the Stineman method, and the data with spatial outliers were filled with values at three stations within 2 km. Using QMS-SDM, irregular and diverse data formats were changed to regular and unit-format data. QMS-SDM application increased the amount of available data by 20-30%, and significantly improved data availability for urban meteorological information services.

The progression of the vertebral body bruise associated with a spinal fracture.

BACKGROUND: Advances in magnetic resonance imaging (MRI) have made it possible to find the vertebral body bruise (VBB), which was not found in computed tomography (CT) after trauma. There has been only one study with adult patients about whether traumatic VBB will cause a collapse of the vertebral body or not. The purpose is to elucidate the progression of VBB in non-osteoporotic adult patients and to identify the possible factors influencing the progression. METHOD: The VBB was defined on MRI as band-like or diffuse zones of high signal intensity on T2-weighted sequences without fracture of the cortex based on CT. The study population with traumatic VBB associated with non-osteoporotic spinal fracture was composed of 15 females and 21 males. The minimal follow-up period was 6 months. The ratio of anterior to posterior heights of the VBB, the ratio of anterior heights of the VBB to the average of those of cranial and caudal adjacent vertebral bodies, the anterior wedge angle of the VBB, and the focal angle around the VBB were compared between the initial and final visits. We evaluated the age of the patients, the C2 plumb line distance, the regional location of VBB, the etiology of VBB, and the treatment methods of the fractures as possible risk factors influencing the progression. RESULTS: There was no difference in the ratios and angles between the initial and final visits. The differences in the ratios and angles between the initial and final visits were not dependent on the possible risk factors. The anterior superior area is the most common in the distribution of VBB. CONCLUSIONS: Unlike compression fractures, the vertebral body with traumatic VBB found in adult patients with non-osteoporotic spinal fractures of AO classification A or B types did not develop collapse. In clinical practice, it is reasonable to diagnose it as a spinal fracture rather than a VBB if the collapse of a possible VBB occurs.

The reaction times and symmetry indices in the bilateral trunk and limb muscles in control subjects and subjects with low back pain that persisted two months or longer.

PURPOSE: This study was conducted to investigate the reaction times and symmetry index (SI) of the bilateral trunk and limb muscles between control subjects and subjects with low back pain (LBP) that persisted for two months or longer. METHODS: Fifty-seven right limb dominant subjects (31 healthy control subjects and 26 subjects with LBP) participated in this study. The subjects were exposed to a slip perturbation (0.24 m/sec velocity for 1.20 cm), which caused them to move forward for 0.10 s in standing while holding a tray. The electromyography (EMG) electrodes were placed on the bilateral erector spinae (ES), rectus abdominis (RA), rectus femoris, hamstring, tibialis anterior, gastrocnemius, biceps brachii (BB), and triceps brachii muscles. The reaction times were analyzed, and the SI was used to compare the bilateral trunk and limb muscles for the degree of asymmetry between groups. RESULTS: The ES reaction time was significantly delayed in the control group (0.33 ± 0.22 vs. 0.22 ± 0.17; t = 2.25, p = 0.03). The SI of reaction times was significantly different on the RA (t = -2.28, p = 0.03), ES (t = -2.36, p = 0.04), and BB (t = -2.15, p = 0.04) muscles between groups. CONCLUSION: The delayed non-dominant ES reaction time might indicate a freedom of pain recurrence in the control group. Although the asymmetry increased on the RA and BB muscles in the LBP group, it decreased on the ES muscle. The asymmetries on the trunk and BB muscles were evident in the LBP group. The asymmetrical reactions in the arm-trunk muscles need to be considered for rehabilitation strategies.

Reoperations after fusion surgeries for degenerative spinal diseases depending on cervical and lumbar regions: a national database study.

BACKGROUND: Reoperation is one of the key factors affecting postoperative clinical outcomes. The reoperation rates of cervical surgeries might be different from those of lumbar surgeries due to the anatomical and biomechanical differences. However, there has been no study to compare the reoperation rate between them. The purpose is to compare reoperation rates after fusion surgeries for degenerative spinal diseases depending on the anatomic region of cervical and lumbar spines. METHOD: We used the Korean Health Insurance Review & Assessment Service national database. Subjects were included if they had any of the primary procedures of fusion combined with the procedure of decompression procedures under the diagnosis of degenerative diseases (n = 42,060). We assigned the patients into two groups based on anatomical regions: cervical and lumbar fusion group (n = 11,784 vs 30,276). The primary endpoint of reoperation was the repeat of any aforementioned fusion procedures. Age, gender, presence of diabetes, associated comorbidities, and hospital types were considered potential confounding factors. RESULTS: The reoperation rate was higher in the patients who underwent lumbar fusion surgery than in the patients who underwent cervical fusion surgery during the entire follow up period (p = 0.0275). A similar pattern was found during the late period (p = 0.0468). However, in the early period, there was no difference in reoperation rates between the two groups. Associated comorbidities and hospital type were noted to be risk factors for reoperation. CONCLUSIONS: The incidence of reoperation was higher in the patients who underwent lumbar fusion surgery than those who underwent cervical fusion surgery for degenerative spinal diseases.

K-line tilt as a novel radiographic parameter in cervical sagittal alignment.

OBJECTIVE: To investigate the relationship between the K-line tilt and classical cervical parameters such as the C2-C7 sagittal vertical axis (SVA), cervical lordosis, and the T1 slope in cervical sagittal alignment. We assessed whether the K-line tilt can be used as an excellent cervical parameter. METHODS: We reviewed 50 patients aged 60-89 years who visited the spine center outpatient clinic from May 2017 to September 2017 through cervical spine lateral radiography and checked the cervical spine parameters. All targeted patients were randomized without any prejudice. Radiographic measurements included the K-line tilt, C2-C7 lordosis, the C2-C7 SVA, the T1 slope, and T1 slope minus C2-C7 lordosis (T1S-CL). Pearson correlation coefficients were calculated between the K-line tilt and each cervical parameter. RESULTS: Of the 50 patients, 33 were men. The mean age of the patients was 70.84 ± 7.52 years. The mean K-line tilt was 11.28 ± 8.31°. The K-line tilt was correlated with the C2-C7 SVA (r = 0.813, P = 0.000) and T1S-CL (r = 0.315, P = 0.026). CONCLUSION: This study showed that the K-line tilt is also a useful parameter like the C2-C7 SVA and T1S-CL in cervical sagittal alignment. These slides can be retrieved under Electronic Supplementary Material.

Osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture without posterior ligament injury: its clinical and radiologic significances.

PURPOSE: To assess the clinical and radiologic outcome of osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture (SPF) without posterior ligament injury. METHODS: A total of 391 patients with single-level osteoporotic thoracolumbar junctional (T10-L2) fracture were selectively enrolled. The patients were divided into two groups by absence (group I) or presence (group II) of SPF. Clinical and radiologic parameters were compared between the two groups. RESULTS: Group I comprised of 332 patients with only vertebral body fracture, and group II comprised of 59 patients with both vertebral body and SPFs. In all cases of group II, SPFs were located just one level above the fractured vertebral body, and the injury of the posterior ligament was not found. At the time of injury, group II patients showed worse outcomes in anterior vertebral body compression percentage, kyphotic Cobb angle, cranial disk status, and the rate of the initial neurologic injury. Kyphotic alignment changes during 1-year follow-up were compared between the conservative subgroups of groups I and II. At the time of injury, there were no statistical differences in anterior vertebral body compression percentage and Cobb angle between the two conservative subgroups. However, the difference was significant after 1-year follow-up. Comparison of kyphotic alignment change at 12 months after diagnosis within group II was done according to the treatment method. Vertebroplasty subgroup in group II did not show benefit even in preventing such kyphotic alignment change, whereas instrumentation subgroup in group II showed lordotic alignment restoration despite more severe kyphotic alignment at the time of injury. CONCLUSIONS: Osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture without posterior ligament injury represented more severe injury with flexion forces on the anterior column and tensile forces on the posterior column, and was related with more severe posttraumatic kyphotic changes during the 12-month follow-up.

Relationship between modic changes and facet joint degeneration in the cervical spine.

PURPOSE: Given that the disc moves simultaneously with facet joints, there would be a relationship between Modic changes and facet joint degeneration in the cervical spine. However, there is no literature investigating the relationship. The purpose is to evaluate the relationship between Modic changes and facet joint degeneration in the cervical spine. METHODS: Ninety-eight patients underwent both computed tomography (CT) and magnetic resonance images (MRI) of the cervical spine. They consisted of fifty-one males and forty-eight females and their mean age was 60.1 years (ranged from 40 years to 81 years). We compared the degree of facet joint degeneration based on CTs with Modic changes based on MRIs from C2-C3 to C6-C7. The degree of facet joint degeneration was classified into four categories and Modic changes were classified into four types. Disc degeneration was determined with Miyazaki's grading system. RESULTS: Facet joint degeneration was most common at C2-C3 and C4-C5 and rarest at C6-C7. Modic changes were most common at C2-C3 and rarest at C6-C7. However, there was no relationship between facet joint degeneration and any Modic changes at the same level. However, the presence of facet joint degeneration and the presence of Modic change are common in high grades of disc degeneration at the same level of the cervical spine. CONCLUSION: Modic changes and facet joint degeneration are most common at C2-C3 in the cervical spine. However, there were no relationships between the presence of Modic changes and facet joint degeneration at the same level of the cervical spine.

Cloning of PaAtg8 and roles of autophagy in adaptation to starvation with respect to the fat body and midgut of the Americana cockroach, Periplaneta americana.

Starvation, in particular amino acid deprivation, induces autophagy in trophocytes (adipocytes), the major component of the fat body cell types, in the larvae of Drosophila melanogaster. However, the fat body of cockroach has two additional cell types: urocytes depositing uric acid in urate vacuoles as a nitrogen resource and mycetocytes harboring an endosymbiont, Blattabacterium cuenoti, which can synthesize amino acids from the metabolites of the stored uric acid. These cells might complement the roles of autophagy in recycling amino acids in the fat body or other organs of cockroaches under starvation. We investigate the presence of autophagy in tissues such as the fat body and midgut of the American cockroach, Periplaneta americana, under starvation by immunoblotting with antibody against Atg8, a ubiquitin-like protein required for the formation of autophagosomes and by electron microscopy. Corresponding changes in acid phosphatase activity were also investigated as representing lysosome activity. Starvation increased the level of an autophagic marker, Atg8-II, in both the tissues, extensively stimulating the formation of autophagic compartments in trophocytes of the fat body and columnar cells of the midgut for over 2 weeks. Acid phosphatase showed no significant increase in the fat body of the starved cockroaches but was higher in the midgut of the continuously fed animals. Thus, a distinct autophagic mechanism operates in these tissues under starvation of 2 weeks and longer. The late induction of autophagy implies exhaustion of the stored uric acid in the fat body. High activity of acid phosphatase in the midgut of the fed cockroaches might represent enhanced assimilation and not an autophagy-related function.

Yam tuber mucilage as a candidate substance for saliva substitute: in vitro study of its viscosity and influences on lysozyme and peroxidase activities.

OBJECTIVE: To investigate the viscosity of yam tuber mucilage (YTM) and its effects on lysozyme and peroxidase activities in solution phase and on surface phase. METHODS: Two kinds of YTM were extracted, one containing both protein and carbohydrate and the other containing mainly carbohydrate. Hen egg-white lysozyme and bovine lactoperoxidase were used as lysozyme and peroxidase sources, respectively. Viscosity was measured with a cone-and-plate digital viscometer. Lysozyme activity was determined using the turbidimetric method, and peroxidase activity was determined using the NbsSCN assay. Hydroxyapatite beads were used as a solid phase. RESULTS: The viscosity values of YTM followed a pattern of a non-Newtonian fluid. The carbohydrate concentration affected the viscosity values at all shear rates, while the protein concentration affected the viscosity values at low shear rates. It could be suggested that YTM composed of 1.0 mg/ml protein and 1.0 mg/ml carbohydrate has viscosity values similar to those of unstimulated whole saliva at shear rates present at routine oral functions. Hydroxyapatite-adsorbed YTM significantly increased the adsorption and subsequent enzymatic activities of lysozyme, but not those of peroxidase. CONCLUSIONS: Yam tuber mucilage has viscoelastic properties similar to those of human saliva and enhances the enzymatic activity of lysozyme on hydroxyapatite surfaces.

Compensatory latency time delays during consecutive perturbations in older adults with and without kinesiophobia.

BACKGROUND: Fear of movement has been related to lower limb activation patterns in older adults. However, insight into consecutive perturbations on stepping strategy while considering fall-related confidence is unknown. RESEARCH QUESTION: Are there latency time delays following three consecutive slip perturbations between subjects with and without kinesiophobia when considering limb dominance and fall efficacy differences? METHODS: There were 15 older adults with kinesiophobia and 15 age- and body mass index (BMI)-matched control subjects. The subjects stood on the platform during three consecutive perturbations (250, 300, and 400 msec excursions), which were produced by a Bertec device. The subjects completed questionnaires to evaluate the psychological features of their fall-related fear (Tampa Scale for Kinesiophobia: TSK) as well as the modified fall efficacy scale (FES). The latency times (msec) measured the time it took for a subject to respond to a translation. RESULTS: Overall, the results of the FES demonstrated a moderate negative association with the TSK (r = -0.52, p = 0.004). There was a significant group difference for the FES (t = 2.78, p = 0.01). The FES demonstrated significant positive correlation coefficients (ranging from 0.40 to 0.51) and significant negative correlation coefficients (ranging from -0.41 to -0.61), except for the slow perturbations. The groups demonstrated a significant interaction on consecutive latency times and limb side (F = 5.84, p = 0.02). The latency time during the fast perturbations on the dominant limb (F = 5.53, p = 0.02) was significantly shorter in the kinesiophobia group. SIGNIFICANCE: The control group demonstrated confidence during fall-related activities, but the latency times were significantly different between groups when considering the dominant limb following repeated slip perturbations. The kinesiophobia group demonstrated shorter latency times on the dominant limb to protect against potential fall-risks from perturbations. The group interactions on limb side and consecutive perturbations need to be considered with fall-related confidence and improved standing balance in older adults with kinesiophobia.

Age-stratified analysis of temporomandibular joint osteoarthritis using cone-beam computed tomography.

Purpose: This study aimed to evaluate age-stratified radiographic features in temporomandibular joint osteoarthritis using cone-beam computed tomography. Materials and Methods: In total, 210 joints from 183 patients (144 females, 39 males, ranging from 12 to 88 years old with a mean age of 44.75±19.97 years) diagnosed with temporomandibular joint osteoarthritis were stratified by age. Mandibular condyle position and bony changes (flattening, erosion, osteophytes, subchondral sclerosis, and subchondral pseudocysts in both the condyle and articular eminence, thickening of the glenoid fossa, joint space narrowing, and joint loose bodies) were evaluated through cone-beam computed tomography. After adjusting for sex, the association between age groups and radiographic findings was analyzed using both a multiple regression model and a multinomial logistic regression model (α=0.05). Results: The prevalence of joint space narrowing and protruded condyle position in the glenoid fossa significantly increased with age (P<0.05). The risks of bony changes, including osteophytes and subchondral pseudocysts in the condyle; flattening, erosion, osteophyte, and subchondral sclerosis in the articular eminence; joint loose bodies; and thickening of the glenoid fossa, also significantly rose with increasing age (P<0.05). The number of radiographic findings increased with age; in particular, the increase was more pronounced in the temporal bone than in the mandibular condyle (P<0.05). Conclusion: Increasing age was associated with a higher frequency and greater diversity of bony changes in the temporal bone, as well as a protruded condyle position in the glenoid fossa, resulting in noticeable joint space narrowing in temporomandibular joint osteoarthritis.

Spontaneous Hematomyelia Associated with the Use of Non-vitamin K Antagonist.

Vitamin K antagonists have been frequently prescribed as anticoagulants with the potential side effect of spontaneous hematomyelia with a poor prognosis. However, to our knowledge, there has been no report of spontaneous hematomyelia combined with the use of a non-vitamin K antagonist. A 63-year-old man presented with left leg weakness, impaired sensation, and urinary retention while taking rivaroxaban (non-vitamin K antagonist) for 4 months for atrial fibrillation. Anticoagulant agents were discontinued. Methylprednisolone pulse therapy was administered without surgical hematoma evacuation. Three months after the initial development of the hematomyelia, the symptoms improved to grade 5 for both lower extremities, and there was complete recovery in sensory and urinary functions. This might be the first description of a complete recovery of neurologic deficits without hematoma evacuation in spontaneous hematomyelia patients caused by non-vitamin K antagonist therapy.

The Effect of Cervical Fusion on Functional Sagittal Spinal Alignment Based on the Inflection Point: Case Series Study.

STUDY DESIGN: A retrospective radiologic study. OBJECTIVE: The inflection point is the disc space between a lordotic and kyphotic segment of spine. To our knowledge, there has been no study evaluating changes in functional sagittal alignment determined by inflection points after cervical fusion surgery. The purpose is to identify changes in functional sagittal alignment after cervical fusion as determined by functional segments between cervicothoracic and thoracolumbar inflection points. METHODS: Standing radiographs of the sagittal whole spine were taken in 62 patients who underwent cervical fusion procedures. We identified cervicothoracic and thoracolumbar inflection points in the sagittal plane and measured Cobb angles of resulting "functional" cervical, thoracic, and lumbar segments. We also measured the C2 and T1 sagittal vertical axis (SVA) distance to S1 and the anatomic cervical lordosis, thoracic kyphosis, lumbar lordosis, spinopelvic parameters, and T1 sagittal slope. We compared the pre- and post-op values. RESULTS: The functional cervical segment and T1 sagittal slope increased postoperatively. C2 and T1 SVA distance to S1 decreased postoperatively. In patients with a single level fusion or lower instrumented vertebra (LIV) proximal or equal to C6, functional cervical segment, and anatomic cervical lordosis increased postoperatively. In those with multiple level fusion or LIV distal or equal to C7, the C2 SVA distance to S1 decreased postoperatively. CONCLUSIONS: After cervical fusion surgery, functional cervical sagittal parameters determined by the inflection point improve without changes in the anatomic sagittal parameters. Postoperative changes in functional sagittal parameters were affected by the number of fused levels and LIV.

Polygenic risk score for tumor aggressiveness and early-onset prostate cancer in Asians.

We attempted to assess the performance of an ethnic-specific polygenic risk score (PRS) designed from a Korean population to predict aggressive prostate cancer (PCa) and early-onset (age < 60). A PRS score comprised of 22 SNPs was computed in 3695 patients gathered from one of 4 tertiary centers in Korea. Males with biopsy or radical prostatectomy-proven PCa were included for analysis, collecting additional clinical parameters such as age, BMI, PSA, Gleason Group (GG), and staging. Patients were divided into 4 groups of PRS quartiles. Intergroup differences were assessed, as well as risk ratio and predictive performance based on GG using logistic regression analysis and AUC. No significant intergroup differences were observed for BMI, PSA, and rate of ≥ T3a tumors on pathology. Rate of GG ≥ 2, GG ≥ 3, and GG ≥ 4 showed a significant pattern of increase by PRS quartile (p < 0.001, < 0.001, and 0.039, respectively). With the lowest PRS quartile as reference, higher PRS groups showed sequentially escalating risk for GG ≥ 2 and GG ≥ 3 pathology, with a 4.6-fold rise in GG ≥ 2 (p < 0.001) and 2.0-fold rise in GG ≥ 3 (p < 0.001) for the highest PRS quartiles. Combining PRS with PSA improved prediction of early onset csPCa (AUC 0.759) compared to PRS (AUC 0.627) and PSA alone (AUC 0.736). To conclude, an ethnic-specific PRS was found to predict susceptibility of aggressive PCa in addition to improving detection of csPCa when combined with PSA in early onset populations. PRS may have a role as a risk-stratification model in actual practice. Large scale, multi-ethnic trials are required to validate our results.

Nationwide sample data analysis of additional surgery rate after anterior or posterior cervical spinal surgery.

Surgical outcomes of degenerative cervical spinal disease are dependent on the selection of surgical techniques. Although a standardized decision cannot be made in an actual clinical setting, continued education is provided to standardize the medical practice among surgeons. Therefore, it is necessary to supervise and regularly update overall surgical outcomes. This study aimed to compare the rate of additional surgery between anterior and posterior surgeries for degenerative cervical spinal disease using the National Health Insurance Service-National Sample Cohort (NHIS-NSC) nationwide patient database. The NHIS-NSC is a population-based cohort with about a million participants. This retrospective cohort study included 741 adult patients (> 18 years) who underwent their first cervical spinal surgery for degenerative cervical spinal disease. The median follow-up period was 7.3 years. An event was defined as the registration of any type of cervical spinal surgery during the follow-up period. Event-free survival analysis was used for outcome analysis, and the following factors were used as covariates for adjustment: location of disease, sex, age, type of insurance, disability, type of hospital, Charles comorbidity Index, and osteoporosis. Anterior cervical surgery was selected for 75.0% of the patients, and posterior cervical surgery for the remaining 25.0%. Cervical radiculopathy due to foraminal stenosis, hard disc, or soft disc was the primary diagnosis in 78.0% of the patients, and central spinal stenosis was the primary diagnosis in 22.0% of them. Additional surgery was performed for 5.0% of the patients after anterior cervical surgery and 6.5% of the patients after posterior cervical surgery (adjusted subhazard ratio, 0.83; 95% confidence interval, 0.40-1.74). The rates of additional surgery were not different between anterior and posterior cervical surgeries. The results would be helpful in evaluating current practice as a whole and adjusting the health insurance policy.

Three-dimensional interpretation of intercanine width change in children: a 9-year longitudinal study.

INTRODUCTION: The immutability of intercanine width has long been the subject of discussion. The aims of this study were to describe the longitudinal intercanine width changes of children from 6 to 14 years of age and to interpret them with a 3-dimensional method. METHODS: Complete dental stone casts were annually prepared for 66 subjects (50 girls, 16 boys) from 6 to 14 years of age. By using 3-dimensional laser scanning and reconstruction software, virtual casts were constructed. Intercanine width was measured as well as the related 3-dimensional measurements, such as the area of the intercanine triangle, the intercanine angle, the radius of the inscribed circle, and the angles formed by the virtual axes of the canines and the occlusal plane. The measurement changes over time were analyzed by using mixed-effects analysis for longitudinal data. RESULTS: There were slight decreases in intercanine widths for both sexes and both arches. However, the amounts of change were relatively small when compared with the initial values and individual random variability. The values of area, the angles formed by the virtual axes of the canines and the occlusal plane, and the radius showed decreasing trends, whereas the intercanine angle exhibited increasing trends during the observation period. Although the intercanine width changed over time, it was not clinically significant, showing relative stability. CONCLUSIONS: The intercanine width of an untreated subject after stabilization in the mouth is considered to be quite stable, even though individual variation is great.

Asymmetrical thoracic-lumbar coordination during trunk rotation between adolescents with and without thoracic idiopathic scoliosis.

STUDY DESIGN: Cross-sectional comparative study. PURPOSE: To compare thoracic-lumbar kinematic changes and coordination based on coupling angles (CAs) in two different directions of trunk rotation between adolescents with idiopathic scoliosis (AIS) and control subjects. Altered three-dimensional (3D) deviations are often apparent in AIS groups during functional activities, such as gait. However, there is a lack of consistent evidence on coordinated motions during different directions of trunk rotation. METHODS: This study included 14 AIS and 17 age-matched control subjects who were all right limb dominant. A motion capture system was utilized to analyze the spinal segment motions. The outcome measures included range of motion (ROM) at the first thoracic (T1), seventh thoracic (T7), and first lumbar (L1) spinous processes as well as the sacral tubercle (S1). The CAs compared in-phase (rotation from right to left) and anti-phase (rotation from left to right) trunk rotations. RESULTS: Although there was no significant association with the spinal segments in the control group, the Cobb angle demonstrated significant positive correlations with anti-phase at T7 and L1 as well as in-phase at L1. Regarding the CAs, the groups demonstrated a significant interaction with both phases (F = 4.7, p = 0.04). The AIS group demonstrated positive correlations with ROM during in-phase at L1 and anti-phase at T7 and L1. CONCLUSION: The coordination based on the CAs of the lumbar spine relative to the thoracic spine significantly decreased during left to right trunk rotation in the AIS group. These results indicated that the AIS group demonstrated directional dissociation toward the dominant side of lumbar rotation. LEVEL OF EVIDENCE: III.

Ankle reaction times with tray usage following a slip perturbation between subjects with and without chronic low back pain.

BACKGROUND: Abnormal stepping strategies have been associated with handheld tasks in subjects with chronic low back pain (LBP). However, the dominant ankle reactions of subjects with LBP remain unclear following a perturbation during handheld tasks. RESEARCH QUESTION: Are there differences in the reaction times of the ankle muscles during handheld tasks between subjects with and without LBP following a treadmill-induced slip perturbation? METHODS: Thirty-seven right limb dominant subjects with LBP and 37 subjects without LBP participated in the study. Each subject was introduced to a slip perturbation (1.37 m/sec velocity for 8.22 cm) with and without a handheld tray in random order. Subjects were allowed to recover by stepping forward for a 0.12 s duration while bilateral tibialis anterior (TA) and gastrocnemius (GA) muscle reaction times were measured by electromyography (EMG). RESULTS: The EMG results indicated that the groups demonstrated significant interactions on the limb sides and muscles (F = 4.86, p = 0.03). The dominant TA reaction time was significantly faster in the LBP group (t = 2.14, p = 0.03) while holding a tray. SIGNIFICANCE: The LBP group demonstrated faster reaction times on the dominant TA muscles during perturbations. Clinicians need to consider dominance-dependent compensatory ankle dorsiflexion strategies in LBP patients to help enhance dynamic balance and control.

Spatiotemporal variations in urban CO2 flux with land-use types in Seoul.

BACKGROUND: Cities are a major source of atmospheric CO2; however, understanding the surface CO2 exchange processes that determine the net CO2 flux emitted from each city is challenging owing to the high heterogeneity of urban land use. Therefore, this study investigates the spatiotemporal variations of urban CO2 flux over the Seoul Capital Area, South Korea from 2017 to 2018, using CO2 flux measurements at nine sites with different urban land-use types (baseline, residential, old town residential, commercial, and vegetation areas). RESULTS: Annual CO2 flux significantly varied from 1.09 kg C m- 2 year- 1 at the baseline site to 16.28 kg C m- 2 year- 1 at the old town residential site in the Seoul Capital Area. Monthly CO2 flux variations were closely correlated with the vegetation activity (r = - 0.61) at all sites; however, its correlation with building energy usage differed for each land-use type (r = 0.72 at residential sites and r = 0.34 at commercial sites). Diurnal CO2 flux variations were mostly correlated with traffic volume at all sites (r = 0.8); however, its correlation with the floating population was the opposite at residential (r = - 0.44) and commercial (r = 0.80) sites. Additionally, the hourly CO2 flux was highly related to temperature. At the vegetation site, as the temperature exceeded 24 ℃, the sensitivity of CO2 absorption to temperature increased 7.44-fold than that at the previous temperature. Conversely, the CO2 flux of non-vegetation sites increased when the temperature was less than or exceeded the 18 ℃ baseline, being three-times more sensitive to cold temperatures than hot ones. On average, non-vegetation urban sites emitted 0.45 g C m- 2 h- 1 of CO2 throughout the year, regardless of the temperature. CONCLUSIONS: Our results demonstrated that most urban areas acted as CO2 emission sources in all time zones; however, the CO2 flux characteristics varied extensively based on urban land-use types, even within cities. Therefore, multiple observations from various land-use types are essential for identifying the comprehensive CO2 cycle of each city to develop effective urban CO2 reduction policies.