1,572 research outputs found

    Observation of a Geometric Hall Effect in a Spinor Bose-Einstein Condensate with a Skyrmion Spin Texture

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    For a spin-carrying particle moving in a spatially varying magnetic field, effective electromagnetic forces can arise due to the geometric phase associated with adiabatic spin rotation of the particle. We report the observation of a geometric Hall effect in a spinor Bose-Einstein condensate with a skyrmion spin texture. Under translational oscillations of the spin texture, the condensate resonantly develops a circular motion in a harmonic trap, demonstrating the existence of an effective Lorentz force. When the condensate circulates, quantized vortices are nucleated in the boundary region of the condensate and the vortex number increases over 100 without significant heating. We attribute the vortex nucleation to the shearing effect of the effective Lorentz force from the inhomogeneous effective magnetic field.Comment: 9 pages, 11 figure

    The effect of age on sagittal plane profile of the lumbar spine according to standing, supine, and various sitting positions

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    BACKGROUND: The sagittal alignment of the spine changes depending on body posture and degenerative changes. This study aimed to observe changes in sagittal alignment of the lumbar spine with different positions (standing, supine, and various sitting postures) and to verify the effect of aging on lumbar sagittal alignment. METHODS: Whole-spine lateral radiographs were obtained for young volunteers (25.4 ± 2.3 years) and elderly volunteers (66.7 ± 1.7 years). Radiographs were obtained in standing, supine, and sitting (30°, 60°, and 90°) positions respectively. We compared the radiological changes in the lordotic and segmental angles in different body positions and at different ages. Upper and lower lumbar lordosis were defined according to differences in anatomical sagittal mobility and kinematic behavior. RESULTS: Lumbar lordosis was greater in a standing position (52.79° and 53.90° in young and old groups, respectively) and tended to decrease as position changed from supine to sitting. Compared with the younger group, the older group showed significantly more lumbar lordosis in supine and 60° and 90° sitting positions (P = 0.043, 0.002, 0.011). Upper lumbar lordosis in the younger group changed dynamically in all changed positions compared with the old group (P = 0.019). Lower lumbar lordosis showed a decreasing pattern in both age groups, significantly changing as position changed from 30° to 60° (P = 0.007, 0.007). CONCLUSIONS: Lumbar lordosis decreases as position changes from standing to 90°sitting. The upper lumbar spine is more flexible in individuals in their twenties compared to those in their sixties. Changes in lumbar lordosis were concentrated in the lower lumbar region in the older group in sitting positions

    A better method of predicting face changes after cosmetic surgery: the partial least squares regression.

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    Accurate prediction of post-surgery face changes is an essential step in the treatment planning of cosmetic surgery. During cosmetic treatment in facial deformity patients, the face does not directly follow the surgical skeletal movements in the underlying bony structures. The algorithms of currently available commercial programs are all based upon the 1-to-1 correspondence ratio and/or the ordinary least squares methods, which is far from being accurate. Predicting face changes after surgery requires a number of variables to consider. Human face landmarks in face photos and x-rays have a 2-dimensional entity. A landmark (or variable) has 2 measurements in the x-axis and the y-axis. A certain degree of vertical repositioning surgery induces horizontal relocation also and vice versa. Furthermore, the face response at a specific face landmark is highly dependent on its adjacent response, and its neighboring points are also dependent on each other. Applying the PLS method would be a solution for prediction and interpretation of this highly correlated 2-dimensional situation. Therefore, the aim of the present study is to propose a better statistical method of predicting face changes after cosmetic surgery by applying the partial least squares regression. In addition, we will also discuss a method to report error analyses for 2-dimensional data. Previously published error reports of 2-dimensional data sets have inappropriately applied 1-dimensional approaches, such as differences in distance or angular measurements. Our visualization method can be applied to 2- dimensional data sets. This method shows errors in both the x-axis and the y-axis simultaneously, which can also identify any between-group differences.OAIID:oai:osos.snu.ac.kr:snu2014-01/104/0000030821/2SEQ:2PERF_CD:SNU2014-01EVAL_ITEM_CD:104USER_ID:0000030821ADJUST_YN:NEMP_ID:A076080DEPT_CD:861CITE_RATE:0FILENAME:2014년03월03일 abstract_pls2014_word_2pages.pdfDEPT_NM:치의학과CONFIRM:

    Clinical effectiveness of omental transposition in facilitating perineal wound healing after abdominoperineal resection: a systematic review

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    Background Omental transposition has been used to facilitate perineal wound healing in patients undergoing abdominoperineal resection (APR). However, there is no high-level evidence supporting the effectiveness of omental transposition in this regard. This study aimed to investigate the clinical efficacy of omental transposition in facilitating perineal wound healing after APR. Methods In this systematic review, we systematically searched the PubMed/MEDLINE, Embase, Scopus, Cochrane Library, and Web of Science databases for literature regarding the topic of our study. Studies published since the inception of each database were considered for review. The outcomes of interest were the perineal wound healing rate at 1 and 3 months postoperatively, perineal wound infection rate, and perineal wound healing period. Results Of the 1,923 studies identified, four articles representing 819 patients (omental transposition patients, n=295) were included in the final analysis. The wound healing rates at 1 and 3 months postoperatively in the omental transposition group (68.5% and 79.7%, respectively) did not significantly differ from those in the control group (57.4% and 78.7%, respectively) (p=0.759 and p=0.731, respectively). Perineal wound infection and chronic wound complication rates, including sinus, dehiscence, and fistula rates, also did not significantly differ between the omental transposition (8% and 7%, respectively) and control (11% and 7%, respectively) groups (p=0.221 and p=0.790, respectively). Conclusion Our results suggest that omental transposition does not affect perineal wound healing in patients who undergo APR

    Clinical Implications of Residual Urine in Korean Benign Prostatic Hyperplasia (BPH) Patients: A Prognostic Factor for BPH-Related Clinical Events

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    Purpose Although post-void residual urine (PVR) is frequently utilized clinically in patients with benign prostatic hyperplasia (BPH), mainly because of its procedural simplicity, its role as a clinical prognostic factor, predictive of treatment goals, is still under much dispute. We investigated the predictive value of PVR for BPH-related clinical events including surgery, acute urinary retention (AUR), and admission following urinary tract infection (UTI). Methods From January to June of 2006, patients over 50 years of age who were diagnosed with BPH for the first time at the outpatient clinic and were then treated for at least 3 years with medications were enrolled in this study. The variables of patients who underwent surgical intervention for BPH, had occurrences of AUR, or required admission due to UTI (Group 1, n=43) were compared with those of patients who were maintained with medications only (Group 2, n=266). Results Group 1 had a significantly higher PVR, more severe symptoms, and a larger prostate at the time of the initial diagnosis in both the univariate and the multivariate analysis. In the 39 patients who underwent BPH-related surgery, although there was a significant change in Qmax at the time of surgery (mean, 13.1 months), PVR and the symptom score remained unchanged compared with the initial evaluation. In the receiver-operating characteristic curve analysis, the area under the curve of Group 1 was in the order of prostate volume (0.834), PVR (0.712), and symptom score (0.621). When redivided by arbitrarily selected PVR cutoffs of 50 mL, 100 mL, and 150 mL, the relative risk of clinical BPH progression was measured as 3.93, 2.61, and 2.11. Conclusions These data indicate that, in the symptomatic Korean population, increased PVR at baseline is a significant indicator of BPH-related clinical events along with increased symptom score or prostate volume
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