Klaassen, Zachary; Tubbs, R Shane; Apaydin, Nihal; Hage, Robert; Jordan, Robert; Loukas, Marios
2011-03-01
Osteoarthritis is a common complication in the elderly and is often associated with osteophyte growth on vertebral bodies. The clinical presentation of vertebral osteophytes is related to anatomical structures adjacent to the spinal column. For instance, cervical osteophytes potentially involve the pharynx and esophagus, leading to dysphagic symptoms that may be accompanied by food aspiration, vocal fold paralysis and obstructive sleep apnea. In addition to anterior cervical osteophytes, posterior and uncinate process osteophytes may form, compressing the spinal cord and vertebral artery blood supply, respectively. Cervical osteophytes have also been shown to form an accessory median atlanto-occipital joint when the relationship between the atlas, dens and basiocciput is involved. In the thorax, the esophagus is often affected by osteophytes and may result in dysphagia. Traumatic and non-traumatic thoracic aorta pseudoaneurysm formation has been attributed to sharp osteophytes lacerating the aorta, a direct complication of the relationship between the aorta anterior vertebral column. Additionally, aspiration pneumonia was reported in patients with compression of a main stem bronchus, due to mechanical compression by thoracic osteophytes. In the lumbar spinal region, the two major structures in close proximity to the spine are the inferior vena cava and abdominal aorta, both of which have been reported to be affected by osteophytes. Treatment of osteophytes is initially conservative with anti-inflammatory medications, followed by surgical removal. Increasing obesity and geriatric populations will continue to result in an array of osteoarthritic degenerative changes such as osteophyte formation. PMID:20383671
ANTERIOR OSTEOPHYTE IDENTIFICATION IN CERVICAL VERTEBRAE
A. T. Chougale
2011-06-01
Full Text Available Radiologist always examines X-ray to determine abnormal changes in cervical, lumbar & thoracic vertebrae. Osteophyte (bony growth may appear at the corners of vertebrae so that vertebral shape becomes abnormal. This paper presents the idea from Image processing techniques such as customised Hough transform which will be used for segmentation which should be independent of rotation, scale, noise & shape. This segmented image will be then used for computing size invariant, convex hull based features to differentiate normal cervical vertebrae from cervical vertebrae containing anterior osteophyte. This approach effectively finds anterior osteophytes in cervical vertebrae.
Dysphagia produced by cervical spine osteophyte. A case report
Claudio Silveri; Juan Manuel Velasco; Asdrúbal Silveri
2014-01-01
We present a case of a 73-year-old male patient with progressive dysphagia, and hoarseness (irritability in the throat). He was studied with the appropriate imaging techniques, and esophagoscopy led to a diagnosis of extrinsic esophageal dysphagia for osteophyte obstruction of the cervical spine due to the arthrosis. A surgical resection was performed, without complications. Some considerations are given on this theme.
Dysphagia produced by cervical spine osteophyte. A case report
Claudio Silveri
2014-01-01
Full Text Available We present a case of a 73-year-old male patient with progressive dysphagia, and hoarseness (irritability in the throat. He was studied with the appropriate imaging techniques, and esophagoscopy led to a diagnosis of extrinsic esophageal dysphagia for osteophyte obstruction of the cervical spine due to the arthrosis. A surgical resection was performed, without complications. Some considerations are given on this theme.
Tsurumoto, Toshiyuki; Saiki, Kazunobu; OKAMOTO, Keishi; Imamura, Takeshi; Maeda, Junichiro; Manabe, Yoshitaka; Wakebe, Tetsuaki
2013-01-01
Objective The aim of this study was to investigate the possibility that periarticular osteophytes plays a role as a appendicular joint stress marker (JSM) which reflects the biomechanical stresses on individuals and populations. Methods A total of 366 contemporary Japanese skeletons (231 males, 135 females) were examined closely to evaluate the periarticular osteophytes of six major joints, the shoulder, elbow, wrist, hip, knee, and ankle and osteophyte scores (OS) were determined using an or...
Spectroscopic Properties of Gold Curvilinear Nanorod Arrays
Yukie Yokota
2016-04-01
Full Text Available We designed and fabricated gold curvilinear nanorod periodical arrays using microfabrication techniques. The gold curvilinear nanorods had two distinct resonant peaks in the near-infrared region between 1630 nm and 3000 nm. Similar peak was observed in gold straight nanorods at specific lengths. At lengths identical to the arc length of the curvilinear nanorod, the peak was in the relative range of 3000 nm, which corresponds to the longitudinal plasmon mode (L-mode. At lengths identical to half of the arc length of the curvilinear nanorod, the peak was close to 1630 nm. Plasmon resonant peaks were tunable in the infrared region by changing the arc length of the curve, the line width, and distance between the curvilinear nanorods. In particular, when two curvilinear nanorods were closely packed in a range of less than 100 nm, the peak wavelength of curvilinear nanorod was shifted due to the plasmonic coupling of each mode.
Anterior cervical osteophytes causing dysphagia and dyspnea: an uncommon entity revisited.
Giger, Roland; Dulguerov, Pavel; Payer, Michael
2006-10-01
Large anterior cervical osteophytes can occur in degeneration of the cervical spine or in diffuse idiopathic skeletal hyperostosis (DISH). We present the case of an 83-year-old patient with progressive dysphagia and acute dyspnea, necessitating emergency tracheotomy. Voluminous anterior cervical osteophytes extending from C3 to C7 and narrowing the pharyngoesophageal segment by external compression and bilateral vocal fold immobility were diagnosed radiologically and by fiberoptic laryngoscopy. Surgical removal of all osteophytes led to the resolution of symptoms. Dyspnea with or without dysphagia caused by hypertrophic anterior cervical osteophytes is an uncommon entity. The exhaustive diagnostic workup proposed in the literature could be simplified by using fiberoptic laryngoscopy and dynamic videofluoroscopy. The causes, treatment, and outcome are discussed. PMID:17216390
Anterior Cervical Osteophytes Causing Dysphagia and Dyspnea: An Uncommon Entity Revisited
Giger, Roland; Dulguerov, Pavel; Payer, Michael
2007-01-01
Large anterior cervical osteophytes can occur in degeneration of the cervical spine or in diffuse idiopathic skeletal hyperostosis (DISH). We present the case of an 83-year-old patient with progressive dysphagia and acute dyspnea, necessitating emergency tracheotomy. Voluminous anterior cervical osteophytes extending from C3 to C7 and narrowing the pharyngoesophageal segment by external compression and bilateral vocal fold immobility were diagnosed radiologically and by fiberoptic laryngoscop...
Seo, Joon Won; Park, Ji Woong; Jang, Jae Chil; Kim, Jae Wook; Lee, Yang Gyun; Kim, Yun Tae; Lee, Seok Min
2013-01-01
Anterior cervical osteophytes are common and usually asymptomatic in elderly people. Due to mechanical compressions, inflammations, and tissues swelling of osteophytes, patients may be presented with multiple complications, such as dysphagia, dysphonia, dyspnea, and pulmonary aspiration. Paradoxical vocal cord motion is an uncommon disease characterized by vocal cord adductions during inspiration and/or expiration. This condition can create shortness of breath, wheezing, respiratory stridor o...
Fokker - Planck equation in curvilinear coordinates
Tanski, Igor A.
2005-01-01
The aim of this paper is to rewrite the Fokker - Planck equation according to transformation of space coordinates. This is nontrivial problem, because transformation of space coordinates induces transformation of velocities. We can use covariant, contravariant or physical velocity components as independent variables in curvilinear coordinate system. These 3 possibilities are considered in this paper and 3 kinds of Fokker - Planck equation in curvilinear coordinates are formulated.
Toshiyuki Tsurumoto
Full Text Available OBJECTIVE: The aim of this study was to investigate the possibility that periarticular osteophytes plays a role as a appendicular joint stress marker (JSM which reflects the biomechanical stresses on individuals and populations. METHODS: A total of 366 contemporary Japanese skeletons (231 males, 135 females were examined closely to evaluate the periarticular osteophytes of six major joints, the shoulder, elbow, wrist, hip, knee, and ankle and osteophyte scores (OS were determined using an original grading system. These scores were aggregated and analyzed statistically from some viewpoints. RESULTS: All of the OS for the respective joints were correlated logarithmically with the age-at-death of the individuals. For 70 individuals, in whom both sides of all six joints were evaluated without missing values, the age-standardized OS were calculated. A right side dominancy was recognized in the joints of the upper extremities, shoulder and wrist joints, and the bilateral correlations were large in the three joints on the lower extremity. For the shoulder joint and the hip joint, it was inferred by some distinctions that systemic factors were relatively large. All of these six joints could be assorted by the extent of systemic and local factors on osteophytes formation. Moreover, when the age-standardized OS of all the joints was summed up, some individuals had significantly high total scores, and others had significantly low total scores; namely, all of the individuals varied greatly in their systemic predisposition for osteophytes formation. CONCLUSIONS: This study demonstrated the significance of periarticular osteophytes; the evaluating system for OS could be used to detect differences among joints and individuals. Periarticular osteophytes could be applied as an appendicular joint stress marker (JSM; by applying OS evaluating system for skeletal populations, intra-skeletal and inter-skeletal variations in biomechanical stresses throughout the
Ramappa Manjunath
2009-02-01
Full Text Available Abstract Introduction Knee pain is a complex problem that can occur after total knee arthroplasty. One cause of knee pain may be due to a retained osteophyte, but it is not clear if the retained osteophyte is sufficient explanation of the pain, as not all patients with retained osteophytes are symptomatic. In fact, the literature shows that excised osteophytes can also recur over a period of time, without any symptoms. Therefore a retained osteophyte alone is probably not sufficient to cause symptoms. Case presentation We present a case of intermittent medial knee pain occurring post-primary total knee arthroplasty, in a patient who underwent several investigations over a period of 5 years. Radiographs showed an osteophyte in the postero-medial femur along with slight tibial component overhang which was normal for that knee implant design. The symptoms eventually settled with excision of only the osteophyte, without altering the tibial component. Conclusion A retained osteophyte alone, or tibial component overhang alone, did not seem to cause significant symptoms in our patient whose symptoms completely settled with excision of the osteophyte alone, without changing the tibial component. Therefore, it seems that the combination of retained osteophyte and tibial component overhang (tibia-femoral component size mismatch are detrimental and therefore best avoided. This report also emphasises the importance of meticulous osteophyte excision and avoiding tibial component overhang during knee arthroplasty.
Jeong, Hyeonghui; Seo, Han Gil; Han, Tai Ryoon; Chung, Chun Kee; Oh, Byung-Mo
2014-01-01
This retrospective case series included five patients who underwent surgical resection of the cervical anterior osteophyte due to dysphagia. Videofluoroscopic swallowing studies (VFSSs) were performed before and after surgery on each patient, and kinematic analysis of the video clips from the VFSS of a 5-mL liquid barium swallow was carried out. Functional oral intake improved after surgery in 3/4 patients who had required a modified diet before surgery. Kinematic analysis showed increases in...
Hayeri, Mohammad Reza; Shiehmorteza, Masoud; Trudell, Debra J.; Hefflin, Tori; Resnick, Donald
2010-01-01
Objective Tibial spiking (i.e., spurring of tibial spines), eburnation, and osteophytes are considered features of osteoarthritis. This investigation employed direct inspection of the medial and lateral tibial plateaus in paleopathological specimens to analyze the frequency and morphological features of osteoarthritis and to define any relationship between the size of osteophytes and that of the intercondylar tibial spines. Materials and Methods A total of 35 tibial bone specimens were evalua...
A series of 685 x-rays films of the cervical spine obtained in coal miners was analyzed to explore the occurrence of narrowed disc spaces and osteophytes in this occupational group, and to examine the association of x-rays changes with age, duration of employment, and duration of occupational exposure to hand-arm vibration. All data were extracted from individual medical files of coal miners examined for suspected hand-arm vibration-related disorders in 1989-1999 at the Occupational Medicine Center in Katowice. The narrowed intervertebral disc spaces were found in 188 coal miners (26.9%) and osteophytes in 332 coal miners (47.5%). The occurrence of degenerative changes in coal miners was similar to that observed in a small group of 68 blue-collar workers (no exposure to hand-arm vibration) employed in the coal industry. Univariate comparisons showed that intervertebral disc spaces and osteophytes were more frequent among older subjects and among subjects with longer duration of employment. The results of logistic regression analysis confirmed statistically significant effect of age, but not of other factors included in the model. When both x-ray changes were grouped together (a combined dependent variable) age remained the only statistically significant explanatory variable. The findings do not support the view that the examined degenerative changes in cervical spine are more prevalent in coal miners and depend on duration of physical work or local exposure to hand-arm vibration in this occupational group. (author)
Superior Dislocation of the Patella in a Young Woman without Osteophytes: A Case Report.
Kataoka, Tatsunori; Iizawa, Norishige; Takai, Shinro
2016-01-01
Superior dislocation of the patella without patellar ligament injury is an extremely rare condition. A review of the English-language literature found only 23 reported cases. In addition, the primary factor for dislocation in most of these cases was considered to be osteophytes in the inferior pole of the patella and the anterior surface of the femoral condyle; only 1 case had no osteophytes. We treated a 19-year-old woman who sustained a painful locking of the left knee after colliding with a friend. Plain radiography and computed tomography showed superior-lateral dislocation of the patella and an interlocking between notches in the inferior pole of the patella and the anterior surface of the femoral condyle. Closed reduction without sedation was performed without difficulty, and the patient was able to walk home without pain. After 1 week, the knee was without problems. The patient had no osteophytes in the knee and had no other common risk factors, such as patella alta, ligamentous laxity, genu recurvatum, and paralytic disorders. After a comparison with previously reported cases of superior patella dislocation, we concluded that the primary factor in the present case might have been a different condition. PMID:26960585
Direct Volume Rendering of Curvilinear Volumes
Vaziri, Arsi; Wilhelms, J.; Challinger, J.; Alper, N.; Ramamoorthy, S.; Kutler, Paul (Technical Monitor)
1998-01-01
Direct volume rendering can visualize sampled 3D scalar data as a continuous medium, or extract features. However, it is generally slow. Furthermore, most algorithms for direct volume rendering have assumed rectilinear gridded data. This paper discusses methods for using direct volume rendering when the original volume is curvilinear, i.e. is divided into six-sided cells which are not necessarily equilateral hexahedra. One approach is to ray-cast such volumes directly. An alternative approach is to interpolate the sample volumes to a rectilinear grid, and use this regular volume for rendering. Advantages and disadvantages of the two approaches in terms of speed and image quality are explored.
A new cause of curvilinear renal calcification: calcified hydrocalycosis
Atakan, Irfan Hueseyin; Pekindil, Goekhan; Alagoel, Buelent; Inci, Osman
2000-10-01
Although many causes of curvilinear renal calcifications have been described, calcified hydrocalycosis mimicking hydatid cyst has not previously been reported. We report a case of hydrocalycosis which was appeared as a curvilinear calcified cystic lesion resulted from staghorn calculus associated with xanthogranolomatous pyelonephritis (XGPN) on intravenous pyelography (IVU) and computed tomography (CT)
A new cause of curvilinear renal calcification: calcified hydrocalycosis
Although many causes of curvilinear renal calcifications have been described, calcified hydrocalycosis mimicking hydatid cyst has not previously been reported. We report a case of hydrocalycosis which was appeared as a curvilinear calcified cystic lesion resulted from staghorn calculus associated with xanthogranolomatous pyelonephritis (XGPN) on intravenous pyelography (IVU) and computed tomography (CT)
Elastic turbulence in a curvilinear channel flow
Jun, Yonggun
2011-01-01
We report detailed quantitative studies of elastic turbulence in a curvilinear channel flow in a dilute polymer solution of high molecular weight polyacrylamide in a high viscosity water-sugar solvent. Detailed studies of the average and rms velocity and velocity gradients profiles reveal an emergence of the boundary layer associated with the nonuniform distribution of the elastic stresses across the channel. The characteristic boundary width is independent of the Weissenberg number Wi and proportional to the channel width that follows from our early investigations of the boundary layer in elastic turbulence of different flow geometries. The appearance of the characteristic spatial scales of the order of the boundary layer width of both velocity and velocity gradient in the correlation functions of the velocity and velocity gradient fields in a bulk flow suggests that rare and strong parcels of excessive elastic stresses, concentrated in the boundary layer, are ejected into the bulk flow similar to jets obser...
General relativistic hydrodynamics in curvilinear coordinates
Montero, Pedro J; Müller, Ewald
2013-01-01
In this paper we report on what we believe is the first successful implementation of relativistic hydrodynamics, coupled to dynamical spacetimes, in spherical polar coordinates without symmetry assumptions. We employ a high-resolution shock-capturing scheme, which requires that the equations be cast in flux-conservative form. One example of such a form is the :Valencia" formulation, which has been adopted in numerous applications, in particular in Cartesian coordinates. Here we generalize this formulation to allow for a reference-metric approach, which provides a natural framework for calculations in curvilinear coordinates. In spherical polar coordinates, for example, it allows for an analytical treatment of the singular r and sin(\\theta) terms that appear in the equations. We experiment with different versions of our generalized Valencia formulation in numerical implementations of relativistic hydrodynamics for both fixed and dynamical spacetimes. We consider a number of different tests -- non-rotating and ...
The Current Scenario of Curvilinear Architecture in Malaysia
Faridah Aduan
2007-12-01
Full Text Available The Bilbao Effect incorporates itself into numerous iconic buildings and grand design s of international architects such as Frank Gehry, Santiago Calatrava, Norman Foster, Renzo Piano, Phillip Cox and Toyo Ito who exploit curvilinear forms as their architectural language .Throughout the world, major events such as the Olympic Games have catalysed the implementation of curvilinear architecture while in Malaysia, the development of Putrajaya has provided opportunity for iconic forms, expressed in curvilinearity. The paper focuses on the current scenario of curvilinear architecture in Malaysia and its posit ion in the international arena. It strives to answer the question of 'How far have Malaysian architects gone in implementing curvilinear architecture?' This is done by first formulating a 'Taxonomy of Rigid Curvilinear Architectural Forms' based on the works of renowned international architects. The taxonomy constitutes the instrument for gauging the position of Malaysian architects. This is achieved by having the works of local architects mapped on to the taxonomy. The research findings indicate that the international architects have advanced by leaps and bounds ahead of their Malaysian counterparts in implementing curvilinear architecture. Several recommendations are proposed in order to narrow this gap .The paper focuses on column-free, rigid and permanent buildings completed from 1990 onwards .
Geometry-based SAR curvilinear feature selection for damage detection
Brett, P.T.B.,; Guida, R.
2012-01-01
Bright curvilinear features in Synthetic Aperture Radar (SAR) images arising from the geometry of urban structures have been successfully used for estimating urban earthquake damage, using single pre- and post-event high resolution amplitude SAR images. In this paper, further automation of the process of selecting candidate curvilinear features for change detection is proposed, based on a model selection using priors derived from idealised building geometry. The technique is demonstrated usin...
Quantifying the curvilinear metabolic scaling in mammals.
Packard, Gary C
2015-10-01
A perplexing problem confronting students of metabolic allometry concerns the convex curvature that seemingly occurs in log-log plots of basal metabolic rate (BMR) vs. body mass in mammals. This putative curvilinearity has typically been interpreted in the context of a simple power function, Y=a*Xb, on the arithmetic scale, with the allometric exponent, b, supposedly increasing steadily as a dependent function of body size. The relationship can be quantified in arithmetic domain by exponentiating a quadratic equation fitted to logarithmic transformations of the original data, but the resulting model is not in the form of a power function and it is unlikely to describe accurately the pattern in the original distribution. I therefore re-examined a dataset for 636 species of mammal and discovered that the relationship between BMR and body mass is well-described by a power function with an explicit, non-zero intercept and lognormal, heteroscedastic error. The model has an invariant allometric exponent of 0.75, so the appearance in prior investigations of a steadily increasing exponent probably was an aberration resulting from undue reliance on logarithmic transformations to estimate statistical models in arithmetic domain. Theoretical constructs relating BMR to body mass in mammals may need to be modified to accommodate a positive intercept in the statistical model, but they do not need to be revised, or rejected, at present time on grounds that the allometric exponent varies with body size. New data from planned experiments will be needed to confirm any hypothesis based on data currently available. PMID:26173580
TomDTurmezei
2011-12-01
Full Text Available Bone is a fundamental component of the disordered joint homeostasis seen in osteoarthritis, a disease that has been primarily characterised by the breakdown of articular cartilage accompanied by local bone changes and a limited degree of joint inflammation. In this review we consider the role of computed tomography imaging and computational analysis in osteoarthritis research, focusing on subchondral bone and osteophytes in the hip. We relate what is already known in this area to what could be explored through this approach in the future in relation to both clinical research trials and the underlying cellular and molecular science of osteoarthritis. We also consider how this area of research could impact on our understanding of the genetics of osteoarthritis.
Tibial spiking (i.e., spurring of tibial spines), eburnation, and osteophytes are considered features of osteoarthritis. This investigation employed direct inspection of the medial and lateral tibial plateaus in paleopathological specimens to analyze the frequency and morphological features of osteoarthritis and to define any relationship between the size of osteophytes and that of the intercondylar tibial spines. A total of 35 tibial bone specimens were evaluated for the degree of osteoarthritis and presence of eburnation. Each plateau was also divided into four quadrants and the presence and size of bone outgrowths were recorded in each quadrant. The ''medial/lateral tibial intercondylar spine index'' for each specimen was calculated as follows: (medial/lateral intercondylar tibial spine height)/(anteroposterior width of the superior tibial surface). The relationships between medial and lateral tibial height indexes with the degree of osteoarthritis were then tested. Osteophytes were observed more frequently in the anterior quadrants of both tibial plateaus than in the posterior quadrants (29 vs 16 for the medial tibial plateau [p = 0.01] and 28 vs 20 for the lateral tibial plateau [p = 0.04]). Eburnation was seen more frequently in the posterior regions of both tibial plateaus than in the anterior regions (17 vs 5, p < 0.01). In specimens with no signs of osteoarthritis the lateral intercondylar tibial index was significantly lower than that in specimens with some degree of osteoarthritis (p = 0.02). The medial intercondylar tibial index of the specimens with no signs of osteoarthritis was not significantly different from that of the specimens with some degree of osteoarthritis (p = 0.45). There was a positive correlation between the lateral spine height index and the overall grading of osteoarthritis, (r = 0.6, p < 0.01). In the anteromedial and posteromedial quadrants of the lateral tibial plateau, the association between the lateral intercondylar tibial spine
Hayeri, Mohammad Reza [Children' s National Medical Center, Department of Radiology, Washington, DC (United States); Shiehmorteza, Masoud; Trudell, Debra J.; Resnick, Donald [University of California San Diego, Department of Radiology, San Diego, CA (United States); Hefflin, Tori [Museum of Man San Diego, San Diego, CA (United States)
2010-09-15
Tibial spiking (i.e., spurring of tibial spines), eburnation, and osteophytes are considered features of osteoarthritis. This investigation employed direct inspection of the medial and lateral tibial plateaus in paleopathological specimens to analyze the frequency and morphological features of osteoarthritis and to define any relationship between the size of osteophytes and that of the intercondylar tibial spines. A total of 35 tibial bone specimens were evaluated for the degree of osteoarthritis and presence of eburnation. Each plateau was also divided into four quadrants and the presence and size of bone outgrowths were recorded in each quadrant. The ''medial/lateral tibial intercondylar spine index'' for each specimen was calculated as follows: (medial/lateral intercondylar tibial spine height)/(anteroposterior width of the superior tibial surface). The relationships between medial and lateral tibial height indexes with the degree of osteoarthritis were then tested. Osteophytes were observed more frequently in the anterior quadrants of both tibial plateaus than in the posterior quadrants (29 vs 16 for the medial tibial plateau [p = 0.01] and 28 vs 20 for the lateral tibial plateau [p = 0.04]). Eburnation was seen more frequently in the posterior regions of both tibial plateaus than in the anterior regions (17 vs 5, p < 0.01). In specimens with no signs of osteoarthritis the lateral intercondylar tibial index was significantly lower than that in specimens with some degree of osteoarthritis (p = 0.02). The medial intercondylar tibial index of the specimens with no signs of osteoarthritis was not significantly different from that of the specimens with some degree of osteoarthritis (p = 0.45). There was a positive correlation between the lateral spine height index and the overall grading of osteoarthritis, (r = 0.6, p < 0.01). In the anteromedial and posteromedial quadrants of the lateral tibial plateau, the association between the lateral
Bednarczyk, Ewa; Lekszycki, Tomasz
2016-08-01
In this paper, a novel evolution equation for capillaries growth is proposed. An essential ingredient is given by the consideration of nutrient supply, for which a novel constitutive equation is also proposed. The biological and mechanical stimuli are assumed to depend in non-local way on relevant kinematical descriptors. The integro-differential equations governing the system evolution are extremely sensitive to parameter variations. However, it was possible to perform some meaningful numerical simulations in which osteophyte onset has been observed. While the choice of these parameters was judiciously driven by biomechanical "a priori" knowledge, the mathematical problems concerning well-posedness, stability and continuous dependence of solutions seem to be very challenging and will be object of future investigations. This effort seems motivated by the fact that proposed equations are, to our knowledge, the first ones allowing for the prediction of osteophytes onset.
Relationship between soy milk intake and radiographic knee joint space narrowing and osteophytes.
Li, Hui; Zeng, Chao; Wei, Jie; Yang, Tuo; Gao, Shu-Guang; Li, Yu-Sheng; Luo, Wei; Xiao, Wen-Feng; Xiong, Yi-Lin; Lei, Guang-Hua
2016-09-01
The purpose of this study was to examine the cross-sectional association between dietary soy milk intake and the prevalence of radiographic knee joint space narrowing (JSN) and osteophytes (OST). Soy milk intake was assessed using a validated semiquantitative food frequency questionnaire and classified into three categories: never, sex), the prevalence of OST decreased in "≥once a day" category (OR 0.52, 95 % CI 0.28-0.98, P = 0.042) and "educational background, diabetes, hypertension, and other dairy product intake) ("≥once a day" category: OR 0.49, 95 % CI 0.26-0.92, P = 0.026; "
Aggressive Behavior and Quality of Friendships: Linear and Curvilinear Associations
Fanti, Kostas A.; Brookmeyer, Kathryn A.; Henrich, Christopher C.; Kuperminc, Gabriel P.
2009-01-01
The current study investigates linear and curvilinear associations between overt aggressive behavior and the adolescents' reports of the quality of their friendships over time. Moderation by gender was also investigated. The sample consisted of 246 boys and 253 girls from the sixth and seventh grades of a large public middle school. Findings…
The modelling of plane curvilinear dipole antenna arrays
Hoblyk, Viktor V.; Liske, O. M.; Yakovenko, Eugenia I.
2005-01-01
In this work the results of mathematical model design for printed dipole antenna arrays are presented. The arrays are feeding by curvilinear transmission slotline. The investigation is important for the antenna arrays theory and useful for the design of antenna arrays with improved characteristics.
A novel curvilinear approach for prostate seed implantation
Podder, Tarun K.; Dicker, Adam P.; Hutapea, Parsaoran; Darvish, Kurosh; Yu Yan [Department of Radiation Oncology, Leo Jenkins Cancer Center, Brody School of Medicine, East Carolina University, Greenville, North Carolina 27834 (United States); Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Department of Mechanical Engineering, Temple University, Philadelphia, Pennsylvania 19122 (United States); Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States)
2012-04-15
Purpose: A new technique called ''curvilinear approach'' for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. Methods: Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V{sub 100}). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D{sub 90}, V{sub 150}, V{sub 200}), urethra (D{sub 30}, D{sub 10}) and rectum (D{sub 5}, V{sub 100}) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. Results: Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D{sub 30} reduced by 10.1% (p < 0.01) and D{sub 10} reduced by 9.9% (p < 0.02). Reduction in rectum dose D{sub 5} was 18.5% (p < 0.03) and V{sub 100} was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V{sub 150} and V{sub 200} coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. Conclusions: Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V{sub 150}, V{sub 200}) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the
Linear and/or curvilinear rail mount system
Thomas, Jackie D. (Inventor); Harris, Lawanna L. (Inventor)
2012-01-01
One or more linear and/or curvilinear mounting rails are coupled to a structure. Each mounting rail defines a channel and at least one cartridge assembly is engaged in the channel. Each cartridge assembly includes a housing that slides within the channel. The housing defines a curvilinearly-shaped recess longitudinally aligned with the channel when the housing is in engagement therewith. The cartridge assembly also includes a cleat fitted in the recess for sliding engagement therealong. The cleat can be coupled to a fastener that passes through the mounting rail and the housing when the housing is so-engaged in the channel. The cleat is positioned in the recess by a position of the fastener.
Higher-Order Finite Element Modeling with Curvilinear Elements
Karban, P.; Mach, F.; Doležel, Ivo
Gliwice : Silesian University of Technology, 2011, s. 5-6. ISBN 978-83-85940-33-3. [INTERNATIONAL CONFERENCE ON FUNDAMENTALS OF ELECTROTECHNICS AND CIRCUIT THEORY /34./. Ustroň (PL), 18.05.2011-21.05.2011] R&D Projects: GA ČR(CZ) GAP102/11/0498 Institutional research plan: CEZ:AV0Z20570509 Keywords : automatic adaptivity * higher-order finite element method * curvilinear elements Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Earthquake Damage Detection in Urban Areas using Curvilinear Features
Brett, PTB; Guida, R.
2013-01-01
Bright curvilinear features arising from the geometry of man-made structures are characteristic of synthetic aperture radar (SAR) images of urban areas, particularly due to double-reflection mechanisms. An approach to urban earthquake damage detection using double-reflection line amplitude change in single-look images has been established in previous literature. Based on this method, this paper introduces an automated tool for fast, unsupervised damage detection in urban areas. Ridge-based cu...
GAIA: A 2-D Curvilinear moving grid hydrodynamic code
The GAIA computer code is developed for time dependent, compressible, multimaterial fluid flow problems, to overcome some drawbacks of traditional 2-D Lagrangian codes. The initial goals of robustness, entropy accuracies, efficiency in presence of large interfacial slip, have already been achieved. The general GODUNOV approach is applied to an arbitrary time varying control-volume formulation. We review in this paper the Riemann solver, the GODUNOV cartesian and curvilinear moving grid schemes and an efficient grid generation algorithm. We finally outline a possible second order accuracy extension
Borazjani, Iman; Ge, Liang; Le, Trung; Sotiropoulos, Fotis
2013-01-01
We develop an overset-curvilinear immersed boundary (overset-CURVIB) method in a general non-inertial frame of reference to simulate a wide range of challenging biological flow problems. The method incorporates overset-curvilinear grids to efficiently handle multi-connected geometries and increase the resolution locally near immersed boundaries. Complex bodies undergoing arbitrarily large deformations may be embedded within the overset-curvilinear background grid and treated as sharp interfac...
Curvilinear shapes and the snake detection hypothesis: An ERP study.
Van Strien, Jan W; Christiaans, Gerwin; Franken, Ingmar H A; Huijding, Jorg
2016-02-01
Consistent with the snake detection hypothesis, previous ERP studies have established a larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Here, we examined to what extent the curvilinear shape of the snake's body drives the larger EPN. To this end, we employed pictures of threatening and nonthreatening species with or without typical curvature. Participants watched a random rapid serial visual presentation of snake, worm, spider, and beetle pictures. The EPN was scored as the mean activity (225-300 ms after picture onset) at occipital and parieto-occipital electrodes. Across electrodes, the EPN was significantly larger for snake pictures than for spider, worm, and beetle pictures, and for spider and worm pictures than for beetle pictures. The results suggest that curvilinear body shapes may partly drive the enhanced EPN. However, the unique cortical response to snakes is not fully explained by this mechanism, and is most probably also determined by other threat-relevant cues. PMID:26481589
Differential Geometrically Consistent Artificial Viscosity in Comoving Curvilinear Coordinates
Höller, Harald; Dorfi, Ernst; Benger, Werner
2013-01-01
Context. High-resolution numerical methods have been developed for nonlinear, discontinuous problems as they appear in simulations of astrophysical objects. One of the strategies applied is the concept of artificial viscosity. Aims. Grid-based numerical simulations ideally utilize problem-oriented grids in order to minimize the necessary number of cells at a given (desired) spatial resolution. We want to propose a modified tensor of artificial viscosity which is employable for generally comoving, curvilinear grids. Methods. We study a differential geometrically consistent artificial viscosity analytically and visualize a comparison of our result to previous implementations by applying it to a simple self-similar velocity field. We give a general introduction to artificial viscosity first and motivate its application in numerical analysis. Then we present how a tensor of artificial viscosity has to be designed when going beyond common static Eulerian or Lagrangian comoving rectangular grids. Results. We find t...
Rapid exploration of curvilinear grids using direct volume rendering
Vangelder, Allen; Wilhelms, Jane
1993-01-01
Fast techniques for direct volume rendering over curvilinear grids of hexahedral cells are developed. This type of 3D grid is common in computational fluid dynamics and finite element analysis. Four new projection methods are presented and compared with each other and with previous methods for tetrahedral grids and rectilinear grids. All four methods use polygon-rendering hardware for speed. A simplified algorithm for visibility ordering, which is based on a combination of breadth-first and depth-first searches, is described. A new multi-pass blending method is described that reduces visual artifacts that are introduced by linear interpolation in hardware where exponential interpolation is needed. Multi-pass blending is of equal interest to hardware-oriented projection methods used on rectilinear grids. Visualization tools that permit rapid data banding and cycling through transfer functions, as well as region restrictions, are described.
Elastic turbulence in curvilinear flows of polymer solutions
Following our first report (A Groisman and V Steinberg 2000 Nature 405 53), we present an extended account of experimental observations of elasticity-induced turbulence in three different systems: a swirling flow between two plates, a Couette-Taylor (CT) flow between two cylinders, and a flow in a curvilinear channel (Dean flow). All three set-ups had a high ratio of the width of the region available for flow to the radius of curvature of the streamlines. The experiments were carried out with dilute solutions of high-molecular-weight polyacrylamide in concentrated sugar syrups. High polymer relaxation time and solution viscosity ensured prevalence of non-linear elastic effects over inertial non-linearity, and development of purely elastic instabilities at low Reynolds number (Re) in all three flows. Above the elastic instability threshold, flows in all three systems exhibit features of developed turbulence. They include: (i) randomly fluctuating fluid motion excited in a broad range of spatial and temporal scales and (ii) significant increase in the rates of momentum and mass transfer (compared with those expected for a steady flow with a smooth velocity profile). Phenomenology, driving mechanisms and parameter dependence of the elastic turbulence are compared with those of the conventional high-Re hydrodynamic turbulence in Newtonian fluids. Some similarities as well as multiple principal differences were found. In two out of three systems (swirling flow between two plates and flow in the curvilinear channel), power spectra of velocity fluctuations decayed rather quickly, following power laws with exponents of about -3.5. It suggests that, being random in time, the flow is rather smooth in space, in the sense that the main contribution to deformation and mixing (and, possibly, elastic energy) is coming from flow at the largest scale of the system. This situation, random in time and smooth in space, is analogous to flows at small scales (below the Kolmogorov
Profiles for voltage-activated currents are multiphasic, not curvilinear
Nissen, Per
2016-01-01
Data for voltage-activation of a potassium channel (Matulef et al. Proc Natl Acad Sci USA 110: 17886-17891. 2013) were, as conventionally done, fitted by the authors by a Boltzmann function, i.e. by a curvilinear profile. Reanalysis of the data reveals however that this interpretation must be rejected in favor of a multiphasic profile, a series of straight lines separated by discontinuous transitions, quite often in the form of noncontiguities (jumps). In contrast to the generally very poor fits to the Boltzmann profiles, the fits to multiphasic profiles are very good. (For the four replicates, the average deviations from the Boltzmann curves were 10- to 100-fold larger than the deviations from the multiphasic profiles.) The difference in the median values was statistically highly significant, P<0.001 in most cases. For the mean values the deviations from the Boltzmann curve were 20-fold larger than the deviations from the multiphasic profile, and the difference in the median values was also highly signifi...
Guarding curvilinear art galleries with vertex or point guards
Karavelas, Menelaos I
2008-01-01
One of the earliest and most well known problems in computational geometry is the so-called art gallery problem. The goal is to compute the minimum possible number guards placed on the vertices of a simple polygon in such a way that they cover the interior of the polygon. In this paper we consider the problem of guarding an art gallery which is modeled as a polygon with curvilinear walls. Our main focus is on polygons the edges of which are convex arcs pointing towards the exterior or interior of the polygon (but not both), named piecewise-convex and piecewise-concave polygons. We prove that, in the case of piecewise-convex polygons, if we only allow vertex guards, $\\lfloor\\frac{4n}{7}\\rfloor-1$ guards are sometimes necessary, and $\\lfloor\\frac{2n}{3}\\rfloor$ guards are always sufficient. Moreover, an $O(n\\log{}n)$ time and $O(n)$ space algorithm is described that produces a vertex guarding set of size at most $\\lfloor\\frac{2n}{3}\\rfloor$. When we allow point guards the afore-mentioned lower bound drops down ...
To define the number and distribution of osteophytes (OPs) in bilateral knee MRI (magnetic resonance imaging) of patients with unilateral anterior cruciate ligament (ACL) rupture. Bilateral knee MRIs of 20 patients with unilateral ACL rupture and reconstruction were retrospectively analyzed for OPs. OPs were graded following the KOSS (knee OA scoring system) classification and their compartmental distribution was assessed following the WORMS (Whole-Organ Magnetic Resonance Imaging Score) classification. All examined knees revealed OPs. Knees with ACL rupture showed significant (p < 0.001) higher total numbers of OPs (mean 11.6; SD ± 4.4) than knees with intact ACL (mean 5.1; SD ± 2.3). Knees with ACL rupture showed increased OP formation in all knee compartments with predominance of marginal OPs in the lateral femorotibial compartment especially on the tibia. Our results show that after knee injury with ACL rupture and reconstruction, all knee compartments were involved in post-traumatic increase of OP formation. The most affected compartment was the lateral femorotibial compartment on the tibial side. (orig.)
Panzer, Stephanie [Department of Radiology, Trauma Center Murnau, Murnau (Germany); Augat, Peter [Trauma Center Murnau and Paracelsus Medical University, Institute of Biomechanics, Murnau (Germany); Atzwanger, Joerg; Hergan, Klaus [University Hospital Salzburg, Paracelsus Medical University, Department of Radiology, Salzburg (Austria)
2012-12-15
To define the number and distribution of osteophytes (OPs) in bilateral knee MRI (magnetic resonance imaging) of patients with unilateral anterior cruciate ligament (ACL) rupture. Bilateral knee MRIs of 20 patients with unilateral ACL rupture and reconstruction were retrospectively analyzed for OPs. OPs were graded following the KOSS (knee OA scoring system) classification and their compartmental distribution was assessed following the WORMS (Whole-Organ Magnetic Resonance Imaging Score) classification. All examined knees revealed OPs. Knees with ACL rupture showed significant (p < 0.001) higher total numbers of OPs (mean 11.6; SD {+-} 4.4) than knees with intact ACL (mean 5.1; SD {+-} 2.3). Knees with ACL rupture showed increased OP formation in all knee compartments with predominance of marginal OPs in the lateral femorotibial compartment especially on the tibia. Our results show that after knee injury with ACL rupture and reconstruction, all knee compartments were involved in post-traumatic increase of OP formation. The most affected compartment was the lateral femorotibial compartment on the tibial side. (orig.)
Use of generalized curvilinear coordinate systems in electromagnetic and hybrid codes
Swift, D.W. [Univ. of Alaska, Fairbanks, AK (United States)
1995-07-01
The author develops a code to simulate the dynamics in the magnetosphere system. The calculation involves a single level, structured, curvilinear 2D mesh. The mesh density is varied to support regions which demand higher resolution.
Shrinkage and whitening of the anterior capsule opening - capsular contraction syndrome - is a well-known complication after continuous curvilinear capsulorrhexis. A 72-year-old women underwent continuous curvilinear capsulorrhexis, phacoemulsification, and implantation of posterior chamber intraocular lens with polymethylmethacrylate haptics. Four months postoperatively, the patient reported deterioration in visual acuity that was resulted due to complete occlusion of anterior capsular opening by fibrotic tissue. The fibrous membrane was excised surgically in capsulorrhexis fashion. (author)
Global-local Finite Element Fracture Analysis of Curvilinearly Stiffened Panels and Adhesive Joints
Islam, Mohammad Majharul
2012-01-01
Global-local finite element analyses were used to study the damage tolerance of curvilinearly stiffened panels; fabricated using the modern additive manufacturing process, the so-called unitized structures, and that of adhesive joints. A damage tolerance study of the unitized structures requires cracks to be defined in the vicinity of the critical stress zone. With the damage tolerance study of unitized structures as the focus, responses of curvilinearly stiffened panels to the combined shear...
Curvilinear T1 hyperintense lesions representing cortical necrosis after cerebral infarction
Kinoshita, Toshibumi; Tamura, Hajime; Kado, Hirotsugu; Okudera, Toshio [Research Institute of Brain and Blood Vessels-Akita, Department of Radiology, Akita (Japan); Ogawa, Toshihide [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Yonago, Tottori (Japan); Yoshida, Yasuji [Research Institute of Brain and Blood Vessels-Akita, Department of Pathology, Akita (Japan)
2005-09-01
Curvilinear T1 hyperintense lesions in the cerebral cortex in patients with subacute infarction were investigated for: (1) the presence or absence of T2* hypointensity and (2) correlations with neuropathologic findings. Thirty-six consecutive patients with subacute to chronic embolic infarction, in whom curvilinear hyperintense lesions in the infarcted cortex were seen on T1-weighted images, underwent echo-planar gradient-echo (GRE-EPI) T2*-weighted imaging. GRE-EPI T2*-weighted imaging revealed no evidence of hemorrhage within the curvilinear T1 hyperintense lesions of the cerebral cortex in all of the patients. In 11 of the 36 patients, focal hypointense lesions were seen in the depth of infarcted gyri on GRE-EPI T2*-weighted images. In the remaining 25 patients, no T2* hypointensities were seen in the infarct zone. Pathological correlation was performed in a patient with middle cerebral artery infarction and curvilinear hyperintense lesions on postmortem T1-weighted images. In the autopsied brain, curvilinear T1 hyperintense lesions corresponded to necrosis of all the cortical layers on histological examination. These data suggest that curvilinear hyperintense lesions in the cerebral cortex on T1-weighted images during the subacute to chronic period of cerebral infarction may not represent hemorrhage. (orig.)
Three-dimensional curvilinear device reconstruction from two fluoroscopic views
Delmas, Charlotte; Berger, Marie-Odile; Kerrien, Erwan; Riddell, Cyril; Trousset, Yves; Anxionnat, René; Bracard, Serge
2015-03-01
In interventional radiology, navigating devices under the sole guidance of fluoroscopic images inside a complex architecture of tortuous and narrow vessels like the cerebral vascular tree is a difficult task. Visualizing the device in 3D could facilitate this navigation. For curvilinear devices such as guide-wires and catheters, a 3D reconstruction may be achieved using two simultaneous fluoroscopic views, as available on a biplane acquisition system. The purpose of this paper is to present a new automatic three-dimensional curve reconstruction method that has the potential to reconstruct complex 3D curves and does not require a perfect segmentation of the endovascular device. Using epipolar geometry, our algorithm translates the point correspondence problem into a segment correspondence problem. Candidate 3D curves can be formed and evaluated independently after identifying all possible combinations of compatible 3D segments. Correspondence is then inherently solved by looking in 3D space for the most coherent curve in terms of continuity and curvature. This problem can be cast into a graph problem where the most coherent curve corresponds to the shortest path of a weighted graph. We present quantitative results of curve reconstructions performed from numerically simulated projections of tortuous 3D curves extracted from cerebral vascular trees affected with brain arteriovenous malformations as well as fluoroscopic image pairs of a guide-wire from both phantom and clinical sets. Our method was able to select the correct 3D segments in 97.5% of simulated cases thus demonstrating its ability to handle complex 3D curves and can deal with imperfect 2D segmentation.
Curvilinear parabolic approximation for surface wave transformation with wave current interaction
Shi, Fengyan; Kirby, James T.
2005-04-01
The direct coordinate transformation method, which only transforms independent variables and retains Cartesian dependent variables, may not be an appropriate method for the purpose of simplifying the curvilinear parabolic approximation of the vector form of the wave-current equation given by Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. In this paper, the covariant-contravariant tensor method is used for the curvilinear parabolic approximation. We use the covariant components of the wave number vector and contravariant components of the current velocity vector so that the derivation of the curvilinear equation closely follows the higher-order approximation in rectangular Cartesian coordinates in Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. The resulting curvilinear equation can be easily implemented using the existing model structure and numerical schemes adopted in the Cartesian parabolic wave model [J.T. Kirby, R.A. Dalrymple, F. Shi, Combined Refraction/Diffraction Model REF/DIF 1, Version 2.6. Documentation and User's Manual, Research Report, Center for Applied Coastal Research, Department of Civil and Environmental Engineering, University of Delaware, Newark, 2004]. Several examples of wave simulations in curvilinear coordinate systems, including a case with wave-current interaction, are shown with comparisons to theoretical solutions or measurement data.
Curvilinear parabolic approximation for surface wave transformation with wave-current interaction
The direct coordinate transformation method, which only transforms independent variables and retains Cartesian dependent variables, may not be an appropriate method for the purpose of simplifying the curvilinear parabolic approximation of the vector form of the wave-current equation given by Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. In this paper, the covariant-contravariant tensor method is used for the curvilinear parabolic approximation. We use the covariant components of the wave number vector and contravariant components of the current velocity vector so that the derivation of the curvilinear equation closely follows the higher-order approximation in rectangular Cartesian coordinates in Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. The resulting curvilinear equation can be easily implemented using the existing model structure and numerical schemes adopted in the Cartesian parabolic wave model [J.T. Kirby, R.A. Dalrymple, F. Shi, Combined Refraction/Diffraction Model REF/DIF 1, Version 2.6. Documentation and User's Manual, Research Report, Center for Applied Coastal Research, Department of Civil and Environmental Engineering, University of Delaware, Newark, 2004]. Several examples of wave simulations in curvilinear coordinate systems, including a case with wave-current interaction, are shown with comparisons to theoretical solutions or measurement data
Lam, Chak Fu; Liang, Jian; Ashford, Susan J; Lee, Cynthia
2015-03-01
This article examined a curvilinear relationship between job insecurity and organizational citizenship behavior (OCB). Drawing from social exchange theory and research on personal control, we developed and tested an explanation for employees' reactions to job insecurity based on their conceptualization of their social exchange relationship with the organization at different levels of job insecurity. Using data from 244 Chinese employees and 102 supervisory ratings of OCB, we found support for a U-shaped relationship between job insecurity and OCB. Moreover, 2 factors--psychological capital and subordinate-supervisor guanxi--moderated the curvilinear relationship, such that the curvilinear relationship is more pronounced among those with lower psychological capital or less positive subordinate-supervisor guanxi. PMID:25602119
Meunier, Jean Christophe; Bisceglia, Rossana; Jenkins, Jennifer M.
2012-01-01
In this study the associations between mothers' and fathers' differential parenting and children's oppositional and emotional problems were examined. A curvilinear relationship between differential parenting and children's outcomes was hypothesized, as well as the combined effect of mothers' and fathers' parenting. Data came from a community…
High Order Finite Difference Methods, Multidimensional Linear Problems and Curvilinear Coordinates
Nordstrom, Jan; Carpenter, Mark H.
1999-01-01
Boundary and interface conditions are derived for high order finite difference methods applied to multidimensional linear problems in curvilinear coordinates. The boundary and interface conditions lead to conservative schemes and strict and strong stability provided that certain metric conditions are met.
Becker, William J.; Cropanzano, Russell
2011-01-01
Previous research pertaining to job performance and voluntary turnover has been guided by 2 distinct theoretical perspectives. First, the push-pull model proposes that there is a quadratic or curvilinear relationship existing between these 2 variables. Second, the unfolding model of turnover posits that turnover is a dynamic process and that a…
Keeley, Jared; Zayac, Ryan; Correia, Christopher
2008-01-01
This study examined the possibility of a curvilinear relationship between statistics anxiety and performance in a statistics course. Eighty-three undergraduate students enrolled in an introductory course completed measures of statistics anxiety and need for achievement at seven points during the semester in conjunction with six tests. Statistics…
Borazjani, Iman; Ge, Liang; Le, Trung; Sotiropoulos, Fotis
2013-04-01
We develop an overset-curvilinear immersed boundary (overset-CURVIB) method in a general non-inertial frame of reference to simulate a wide range of challenging biological flow problems. The method incorporates overset-curvilinear grids to efficiently handle multi-connected geometries and increase the resolution locally near immersed boundaries. Complex bodies undergoing arbitrarily large deformations may be embedded within the overset-curvilinear background grid and treated as sharp interfaces using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, Journal of Computational Physics, 2007). The incompressible flow equations are formulated in a general non-inertial frame of reference to enhance the overall versatility and efficiency of the numerical approach. Efficient search algorithms to identify areas requiring blanking, donor cells, and interpolation coefficients for constructing the boundary conditions at grid interfaces of the overset grid are developed and implemented using efficient parallel computing communication strategies to transfer information among sub-domains. The governing equations are discretized using a second-order accurate finite-volume approach and integrated in time via an efficient fractional-step method. Various strategies for ensuring globally conservative interpolation at grid interfaces suitable for incompressible flow fractional step methods are implemented and evaluated. The method is verified and validated against experimental data, and its capabilities are demonstrated by simulating the flow past multiple aquatic swimmers and the systolic flow in an anatomic left ventricle with a mechanical heart valve implanted in the aortic position. PMID:23833331
Claassen, Daniel O; Dobolyi, David G; Isaacs, David A; Roman, Olivia C; Herb, Joshua; Wylie, Scott A; Neimat, Joseph S; Donahue, Manus J; Hedera, Peter; Zald, David H; Landman, Bennett A; Bowman, Aaron B; Dawant, Benoit M; Rane, Swati
2016-05-01
Advancing age and disease duration both contribute to cortical thinning in Parkinson's disease (PD), but the pathological interactions between them are poorly described. This study aims to distinguish patterns of cortical decline determined by advancing age and disease duration in PD. A convenience cohort of 177 consecutive PD patients, identified at the Vanderbilt University Movement Disorders Clinic as part of a clinical evaluation for Deep Brain Stimulation (age: M= 62.0, SD 9.3), completed a standardized clinical assessment, along with structural brain Magnetic Resonance Imaging scan. Age and gender matched controls (n=53) were obtained from the Alzheimer Disease Neuroimaging Initiative and Progressive Parkinson's Marker Initiative (age: M= 63.4, SD 12.2). Estimated changes in cortical thickness were modeled with advancing age, disease duration, and their interaction. The best-fitting model, linear or curvilinear (2(nd), or 3(rd) order natural spline), was defined using the minimum Akaike Information Criterion, and illustrated on a 3-dimensional brain. Three curvilinear patterns of cortical thinning were identified: early decline, late decline, and early-stable-late. In contrast to healthy controls, the best-fit model for age related changes in PD is curvilinear (early decline), particularly in frontal and precuneus regions. With advancing disease duration, a curvilinear model depicts accelerating decline in the occipital cortex. A significant interaction between advancing age and disease duration is evident in frontal, motor, and posterior parietal areas. Study results support the hypothesis that advancing age and disease duration differentially affect regional cortical thickness and display regional dependent linear and curvilinear patterns of thinning. PMID:27330836
A method of smooth bivariate interpolation for data given on a generalized curvilinear grid
Zingg, David W.; Yarrow, Maurice
1992-01-01
A method of locally bicubic interpolation is presented for data given at the nodes of a two-dimensional generalized curvilinear grid. The physical domain is transformed to a computational domain in which the grid is uniform and rectangular by a generalized curvilinear coordinate transformation. The metrics of the transformation are obtained by finite differences in the computational domain. Metric derivatives are determined by repeated application of the chain rule for partial differentiation. Given the metrics and the metric derivatives, the partial derivatives required to determine a locally bicubic interpolant can be estimated at each data point using finite differences in the computational domain. A bilinear transformation is used to analytically transform the individual quadrilateral cells in the physical domain into unit squares, thus allowing the use of simple formulas for bicubic interpolation.
MATHEMATICAL MODEL FOR 2-D TIDAL FLOW AND WATER QUALITY WITH ORTHOGONAL CURVILINEAR COORDINATES
Liu Yu-ling; Wei Wen-li; Shen Yong-ming
2003-01-01
This paper presents a numerical method forsimulating the 2-D tidal flow and water quality with the or-thogonal curvilinear coordinates. In order to overcome thecomputational difficulties in natural rivers, such as the com-plicated boundary figures, the great disparity between lengthand width of computational domain, etc. , orthogonal bounda-ry-fitted grid was used. The irregular domain in physical planewas transformed into a rectangular domain in a transformedplane, and the depth-averaged momentum equations and massequation were given and discretized based on the alternatingdirection implicit finite difference scheme in curvilinear coordi-nates. The application of the presented method was illustratedby an example of analyzing the Yangtze River in the vicinity ofNanjing city. A fair agreement between the measured data andcomputed results demonstrates the validity of the developedmethod.
Modeling of a Curvilinear Planar Crack with a Curvature-Dependent Surface Tension
Zemlyanova, A. Y.
2012-01-01
An approach to modeling fracture incorporating interfacial mechanics is applied to the example of a curvilinear plane strain crack. The classical Neumann boundary condition is augmented with curvature-dependent surface tension. It is shown that the considered model eliminates the integrable crack-tip stress and strain singularities of order 1/2 present in the classical linear fracture mechanics solutions, and also leads to the sharp crack opening that is consistent with empirical observations. Unlike for the case of a straight crack, for a general curvilinear crack some components of the stresses and the derivatives of the displacements may still possess weaker singularities of a logarithmic type. Generalizations of the present study that lead to complete removal of all crack-tip singularities, including logarithmic, are the subject of a future paper. © 2012 Society for Industrial and Applied Mathematics.
'Perfectly' curvilinear profiles for binding as determined by ITC may in fact be multiphasic
Nissen, Per
2016-01-01
In a structural analysis of the proteasome activator PafE in Mycobacterium tuberculosis, the binding of the activator or shorter constructs to the 20S proteasome core particle (20S CP) or derivatives was measured by isothermal titration calorimetry (Bai et al. Proc Natl Acad Sci USA 113: E1983-E1992. 2016). The data were fitted by the authors by nonlinear least squares to give curvilinear profiles that, at least in part, appear to fit the data very well. However, reanalysis of the data shows that the profiles are much better (P < 0.001) represented as multiphasic, i.e. by a series of straight lines separated by discontinuous transitions, often in the form jumps, than by the conventional curvilinear profiles.
A New View on Geometry Optimization: the Quasi-Independent Curvilinear Coordinate Approximation
Németh, Károly; Challacombe, Matt
2004-01-01
This article presents a new and efficient alternative to well established algorithms for molecular geometry optimization. The new approach exploits the approximate decoupling of molecular energetics in a curvilinear internal coordinate system, allowing separation of the 3N-dimensional optimization problem into an O(N) set of quasi-independent one-dimensional problems. Each uncoupled optimization is developed by a weighted least squares fit of energy gradients in the internal coordinate system...
Reduced curvilinear velocity of boar sperm on substrates with increased hydrophobicity
Mears, M.; Kennelly, T.M.; Geoghegan, M; Howse, J.R.; Tarmey, D.S.; Pacey, A. A.
2014-01-01
The curvilinear velocity (VCL) of boar spermatozoa between standard microscopy glassware decreases when the slides are coated with the hydrophobic polymer polystyrene (PS) compared with the less hydrophobic poly(methyl methacrylate) (PMMA) coating. Sperm from three boars were observed and analyzed using particle tracking software. The VCL did not differ significantly between coatings of different thickness, indicating no penetration of the sperm into the coating and that only the surface laye...
Modeling of a curvilinear planar crack with a curvature-dependent surface tension
Zemlyanova, A Y
2011-01-01
In this paper, an approach to modeling fracture incorporating interfacial mechanics is applied to the example of a curvilinear plane strain crack. The classical Neumann boundary condition is augmented with curvature-dependent surface tension. It is shown that the considered model eliminates the integrable crack-tip stress and strain singularities of order 1/2 present in the classical linear fracture mechanics solutions, and also leads to the sharp crack opening that is consistent with empirical observations.
Cannistraci, Carlo
2010-09-01
Motivation: Nonlinear small datasets, which are characterized by low numbers of samples and very high numbers of measures, occur frequently in computational biology, and pose problems in their investigation. Unsupervised hybrid-two-phase (H2P) procedures-specifically dimension reduction (DR), coupled with clustering-provide valuable assistance, not only for unsupervised data classification, but also for visualization of the patterns hidden in high-dimensional feature space. Methods: \\'Minimum Curvilinearity\\' (MC) is a principle that-for small datasets-suggests the approximation of curvilinear sample distances in the feature space by pair-wise distances over their minimum spanning tree (MST), and thus avoids the introduction of any tuning parameter. MC is used to design two novel forms of nonlinear machine learning (NML): Minimum Curvilinear embedding (MCE) for DR, and Minimum Curvilinear affinity propagation (MCAP) for clustering. Results: Compared with several other unsupervised and supervised algorithms, MCE and MCAP, whether individually or combined in H2P, overcome the limits of classical approaches. High performance was attained in the visualization and classification of: (i) pain patients (proteomic measurements) in peripheral neuropathy; (ii) human organ tissues (genomic transcription factor measurements) on the basis of their embryological origin. Conclusion: MC provides a valuable framework to estimate nonlinear distances in small datasets. Its extension to large datasets is prefigured for novel NMLs. Classification of neuropathic pain by proteomic profiles offers new insights for future molecular and systems biology characterization of pain. Improvements in tissue embryological classification refine results obtained in an earlier study, and suggest a possible reinterpretation of skin attribution as mesodermal. © The Author(s) 2010. Published by Oxford University Press.
"All or nothing": attachment avoidance and the curvilinear effects of partner support.
Girme, Yuthika U; Overall, Nickola C; Simpson, Jeffry A; Fletcher, Garth J O
2015-03-01
People high in attachment avoidance typically respond more negatively to partner support, but some research suggests they can be calmed by high levels of practical support. In the present research, we attempted to reconcile these inconsistencies by modeling curvilinear associations between romantic partners' support and support recipients' outcomes and testing whether these curvilinear associations were moderated by recipients' degree of attachment avoidance. We examined the effect of partner support during support-relevant discussions (Studies 1-3) and in daily life (Study 4) on support recipients' distress (Studies 1-4), self-efficacy (Studies 2 and 3), perceived partner control/criticism (Studies 2 and 4), and distancing from the partner (Study 4). The results and a meta-analysis across all four studies (N = 298 couples) demonstrated that the curvilinear effect of practical support on recipients' outcomes was moderated by attachment avoidance. Highly avoidant recipients exhibited more negative responses as their partner provided them low-to-moderate levels of practical support, including increasing distress, perceived partner control/criticism and distancing, and decreasing self-efficacy. However, as partners' practical support shifted from moderate to high levels, highly avoidant recipients experienced more positive outcomes, including decreasing distress, perceived partner control/criticism and distancing, and increasing self-efficacy. Less avoidant individuals were resilient and experienced better outcomes regardless of the level of partner support they received. These results demonstrate the utility of curvilinear models in reconciling the costs and benefits of support, and indicate that high levels of practical support can overcome the defenses of highly avoidant individuals by offering undeniable evidence of the partner's availability. PMID:25751717
Formulations of the 3+1 evolution equations in curvilinear coordinates
Alcubierre, Miguel; Mendez, Martha D.
2010-01-01
Following Brown, in this paper we give an overview of how to modify standard hyperbolic formulations of the 3+1 evolution equations of General Relativity in such a way that all auxiliary quantities are true tensors, thus allowing for these formulations to be used with curvilinear sets of coordinates such as spherical or cylindrical coordinates. After considering the general case for both the Nagy-Ortiz-Reula (NOR) and the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulations, we specialize t...
Pande, M
1993-01-01
The successful use of continuous curvilinear (circular) capsulorhexis (CCC) in planned extracapsular cataract extraction (ECCE) is dependent on the feasibility of safe nuclear delivery through the smaller anterior capsular opening. Experimental evidence supports the proposition that the anterior capsular rim can stretch without tearing to dimensions which allow for safe nucleus delivery. Clinical reports of accidental intracapsular expression during nucleus delivery in CCC seemingly contradic...
Distributed Representation of Curvilinear Self-Motion in the Macaque Parietal Cortex
Zhixian Cheng
2016-05-01
Full Text Available Information about translations and rotations of the body is critical for complex self-motion perception during spatial navigation. However, little is known about the nature and function of their convergence in the cortex. We measured neural activity in multiple areas in the macaque parietal cortex in response to three different types of body motion applied through a motion platform: translation, rotation, and combined stimuli, i.e., curvilinear motion. We found a continuous representation of motion types in each area. In contrast to single-modality cells preferring either translation-only or rotation-only stimuli, convergent cells tend to be optimally tuned to curvilinear motion. A weighted summation model captured the data well, suggesting that translation and rotation signals are integrated subadditively in the cortex. Interestingly, variation in the activity of convergent cells parallels behavioral outputs reported in human psychophysical experiments. We conclude that representation of curvilinear self-motion perception is widely distributed in the primate sensory cortex.
To evaluate how the reading of knee radiographs by site investigators differs from that by an expert musculoskeletal radiologist who trained and validated them in a multicenter knee osteoarthritis (OA) study. A subset of participants from the Osteoarthritis Initiative progression cohort was studied. Osteophytes and joint space narrowing (JSN) were evaluated using Kellgren-Lawrence (KL) and Osteoarthritis Research Society International (OARSI) grading. Radiographs were read by site investigators, who received training and validation of their competence by an expert musculoskeletal radiologist. Radiographs were re-read by this radiologist, who acted as a central reader. For KL and OARSI grading of osteophytes, discrepancies between two readings were adjudicated by another expert reader. Radiographs from 96 subjects (49 women) and 192 knees (138 KL grade ≥ 2) were included. The site reading showed moderate agreement for KL grading overall (kappa=0.52) and for KL ≥ 2 (i.e., radiographic diagnosis of ''definite OA''; kappa=0.41). For OARSI grading, the site reading showed substantial agreement for lateral and medial JSN (kappa=0.65 and 0.71), but only fair agreement for osteophytes (kappa=0.37). For KL grading, the adjudicator's reading showed substantial agreement with the centralized reading (kappa=0.62), but only slight agreement with the site reading (kappa = 0.10). Site investigators over-graded osteophytes compared to the central reader and the adjudicator. Different thresholds for scoring of JSN exist even between experts. Our results suggest that research studies using radiographic grading of OA should use a centralized reader for all grading. (orig.)
Generation of orthogonal curvilinear grids on the sphere surface based on Laplace-Beltrami equations
In this paper, Laplace-Beltrami equations are used to generate orthogonal curvilinear grids on the sphere for ocean models. In addition to overcoming the pole-problem, the grid configuration has quasi-uniform cell-size on the whole sphere. Some quantities such as the grid length along two directions, the angle deviation from orthogonality, the area of the cell to evaluate the quality of the grid, which demonstrate the grid produced is fit to be a model grid on which the finite difference method or finite volume method can be implemented for numerical simulating of global atmosphere and ocean dynamics on large scale
A curvilinear, fully implicit, conservative electromagnetic PIC algorithm in multiple dimensions
Chacón, L.; Chen, G.
2016-07-01
We extend a recently proposed fully implicit PIC algorithm for the Vlasov-Darwin model in multiple dimensions (Chen and Chacón (2015) [1]) to curvilinear geometry. As in the Cartesian case, the approach is based on a potential formulation (ϕ, A), and overcomes many difficulties of traditional semi-implicit Darwin PIC algorithms. Conservation theorems for local charge and global energy are derived in curvilinear representation, and then enforced discretely by a careful choice of the discretization of field and particle equations. Additionally, the algorithm conserves canonical-momentum in any ignorable direction, and preserves the Coulomb gauge ∇ ṡ A = 0 exactly. An asymptotically well-posed fluid preconditioner allows efficient use of large cell sizes, which are determined by accuracy considerations, not stability, and can be orders of magnitude larger than required in a standard explicit electromagnetic PIC simulation. We demonstrate the accuracy and efficiency properties of the algorithm with numerical experiments in mapped meshes in 1D-3V and 2D-3V.
Kiel, Elizabeth J; Premo, Julie E; Buss, Kristin A
2016-04-01
Various parenting behaviors (e.g., protection, intrusiveness, sensitivity) have been shown to impact young children's anxiety development, particularly for temperamentally inhibited children. These behaviors have sometimes predicted both increases and decreases in anxiety in inhibited children, suggesting that linear relations may not adequately model their influence. In the current study, we proposed the dimension of encouragement to approach novelty to characterize parenting behavior ranging from very little encouragement (i.e., protective behavior) to very strong encouragement (i.e., intrusiveness), with gentle encouragement residing in the middle. In a sample of 110 toddlers (48 female, 62 male) and their mothers, the linear and curvilinear effects of this parenting dimension were investigated in relation to change in child separation anxiety and shyness from age 2 to age 3. Inhibited temperament was also investigated as a moderator. Encouragement to approach novelty displayed the hypothesized curvilinear relation to change in separation anxiety, but not shyness, at extreme levels of inhibited temperament. Toddlers increased in separation anxiety when mothers' encouragement resided at either extreme end of the continuum, with lower child anxiety occurring when mothers displayed behavior closer to the middle of the continuum. Implications for the study of parenting outcomes for inhibited toddlers are discussed. PMID:26050798
Wave propagations of curvilinear motors driven by partially laminated piezoelectric actuators
A piezoelectric arc stator is the key component delivering driving actions to an ultrasonic curvilinear motor. The arc stator drives the rotor along the arc structure to any specific angular position. Usually conventional stators in ultrasonic motors are fully bounded with piezoelectric patch actuators. To reduce production costs while maintaining similar driving characteristics, an arc stator partially bonded with piezoelectric actuators is proposed and its dynamic characteristics are analyzed in this study. The effect of actuator locations on the wave propagation is investigated. Both analytical and finite element results demonstrate similar dynamic responses. That is, the response of the wave propagation depends on specific locations of piezoelectric actuators. One of the two configurations investigated shows that the partially laminated piezoelectric actuator pattern can also generate rather steady traveling waves on the stator with consistent wave amplitude. This implies that the partially laminated actuator technique could be an alternative actuator pattern to the fully laminated actuators in the design of ultrasonic curvilinear motors or other finite-length ultrasonic motors
Development of a computational environment for the General Curvilinear Ocean Model
The General Curvilinear Ocean Model (GCOM) differs significantly from the traditional approach, where the use of Cartesian coordinates forces the model to simulate terrain as a series of steps. GCOM utilizes a full three-dimensional curvilinear transformation, which has been shown to have greater accuracy than similar models and to achieve results more efficiently. The GCOM model has been validated for several types of water bodies, different coastlines and bottom shapes, including the Alarcon Seamount, Southern California Coastal Region, the Valencia Lake in Venezuela, and more recently the Monterey Bay. In this paper, enhancements to the GCOM model and an overview of the computational environment (GCOM-CE) are presented. Model improvements include migration from F77 to F90; approach to a component design; and initial steps towards parallelization of the model. Through the use of the component design, new models are being incorporated including biogeochemical, pollution, and sediment transport. The computational environment is designed to allow various client interactions via secure Web applications (portal, Web services, and Web 2.0 gadgets). Features include building jobs, managing and interacting with long running jobs; managing input and output files; quick visualization of results; publishing of Web services to be used by other systems such as larger climate models. The CE is based mainly on Python tools including a grid-enabled Pylons Web application Framework for Web services, pyWSRF (python-Web Services-Resource Framework), pyGlobus based web services, SciPy, and Google code tools.
Nevill, A M; Allen, S V; Ingham, S A
2011-02-01
Previous studies have investigated the determinants of indoor rowing using correlations and linear regression. However, the power demands of ergometer rowing are proportional to the cube of the flywheel's (and boat's) speed. A rower's speed, therefore, should be proportional to the cube root (0.33) of power expended. Hence, the purpose of the present study was to explore the relationship between 2000 m indoor rowing speed and various measures of power of 76 elite rowers using proportional, curvilinear allometric models. The best single predictor of 2000 m rowing ergometer performance was power at VO(2max)(WVO(2max))(0.28), that explained R(2)=95.3% in rowing speed. The model realistically describes the greater increment in power required to improve a rower's performance by the same amount at higher speeds compared with that at slower speeds. Furthermore, the fitted exponent, 0.28 (95% confidence interval 0.226-0.334) encompasses 0.33, supporting the assumption that rowing speed is proportional to the cube root of power expended. Despite an R(2)=95.3%, the initial model was unable to explain "sex" and "weight-class" differences in rowing performances. By incorporating anaerobic as well as aerobic determinants, the resulting curvilinear allometric model was common to all rowers, irrespective of sex and weight class. PMID:19883389
Marker Pen Lithography for Flexible and Curvilinear On-Chip Energy Storage
Jiang, Qiu
2015-07-14
On-chip energy storage using microsupercapacitors can serve the dual role of supplementing batteries for pulse power delivery, and replacement of bulky electrolytic capacitors in ac-line filtering applications. Despite complexity and processing costs, microfabrication techniques are being employed in fabricating a great variety of microsupercapacitor devices. Here, a simple, cost-effective, and versatile strategy is proposed to fabricate flexible and curvilinear microsupercapacitors (MSCs). The protocol involves writing sacrificial ink patterns using commercial marker pens on rigid, flexible, and curvilinear substrates. It is shown that this process can be used in both lift-off and etching modes, and the possibility of multistack design of active materials using simple pen lithography is demonstrated. As a prototype, this method is used to produce conducting polymer MSCs involving both poly(3,4-ethylenedioxythiophene), polyaniline, and metal oxide (MnO
Development of a computational environment for the General Curvilinear Ocean Model
Thomas, Mary P.; Castillo, Jose E.
2009-07-01
The General Curvilinear Ocean Model (GCOM) differs significantly from the traditional approach, where the use of Cartesian coordinates forces the model to simulate terrain as a series of steps. GCOM utilizes a full three-dimensional curvilinear transformation, which has been shown to have greater accuracy than similar models and to achieve results more efficiently. The GCOM model has been validated for several types of water bodies, different coastlines and bottom shapes, including the Alarcon Seamount, Southern California Coastal Region, the Valencia Lake in Venezuela, and more recently the Monterey Bay. In this paper, enhancements to the GCOM model and an overview of the computational environment (GCOM-CE) are presented. Model improvements include migration from F77 to F90; approach to a component design; and initial steps towards parallelization of the model. Through the use of the component design, new models are being incorporated including biogeochemical, pollution, and sediment transport. The computational environment is designed to allow various client interactions via secure Web applications (portal, Web services, and Web 2.0 gadgets). Features include building jobs, managing and interacting with long running jobs; managing input and output files; quick visualization of results; publishing of Web services to be used by other systems such as larger climate models. The CE is based mainly on Python tools including a grid-enabled Pylons Web application Framework for Web services, pyWSRF (python-Web Services-Resource Framework), pyGlobus based web services, SciPy, and Google code tools.
Parkes, Katharine R
2016-05-01
Although additive combinations of age and work environment characteristics have been found to predict sleep impairment, possible age x work environment interactions have been largely disregarded. The present study examined linear and curvilinear interactions of age with work environment measures in relation to sleep quality and duration. Survey data were collected from offshore day-shift personnel (N = 901). Main effects and interactions of the age terms with work environment measures (job demand, control, and social support, physical environment and strenuous work) were evaluated. Sleep duration was predicted by a curvilinear interaction, age(2)x job demand (p social support interaction (p < .002); sleep quality was predicted by age x job demand (p < .002). Job control and physical environment showed significant additive effects. At a time when older employees are encouraged to remain in the workforce, the findings serve to increase understanding of how ageing and work demands jointly contribute to sleep impairment. PMID:26851463
Kaul, Upender K. (Inventor)
2009-01-01
Modeling and simulation of free and forced structural vibrations is essential to an overall structural health monitoring capability. In the various embodiments, a first principles finite-difference approach is adopted in modeling a structural subsystem such as a mechanical gear by solving elastodynamic equations in generalized curvilinear coordinates. Such a capability to generate a dynamic structural response is widely applicable in a variety of structural health monitoring systems. This capability (1) will lead to an understanding of the dynamic behavior of a structural system and hence its improved design, (2) will generate a sufficiently large space of normal and damage solutions that can be used by machine learning algorithms to detect anomalous system behavior and achieve a system design optimization and (3) will lead to an optimal sensor placement strategy, based on the identification of local stress maxima all over the domain.
Lorenz, Tierney Ahrold; Harte, Christopher B; Hamilton, Lisa Dawn; Meston, Cindy M
2012-01-01
There is increasing evidence that women's physiological sexual arousal is facilitated by moderate sympathetic nervous system (SNS) activation. Literature also suggests that the level of SNS activation may play a role in the degree to which SNS activity affects sexual arousal. We provide the first empirical examination of a possible curvilinear relationship between SNS activity and women's genital arousal using a direct measure of SNS activation in 52 sexually functional women. The relationship between heart rate variability (HRV), a specific and sensitive marker of SNS activation, and vaginal pulse amplitude (VPA), a measure of genital arousal, was analyzed. Moderate increases in SNS activity were associated with higher genital arousal, while very low or very high SNS activation was associated with lower genital arousal. These findings imply that there is an optimal level of SNS activation for women's physiological sexual arousal. PMID:22092348
Loss of lag-response curvilinearity of indices of heart rate variability in congestive heart failure
Smith Michael L
2006-06-01
Full Text Available Abstract Background Heart rate variability (HRV is known to be impaired in patients with congestive heart failure (CHF. Time-domain analysis of ECG signals traditionally relies heavily on linear indices of an essentially non-linear phenomenon. Poincaré plots are commonly used to study non-linear behavior of physiologic signals. Lagged Poincaré plots incorporate autocovariance information and analysis of Poincaré plots for various lags can provide interesting insights into the autonomic control of the heart. Methods Using Poincaré plot analysis, we assessed whether the relation of the lag between heart beats and HRV is altered in CHF. We studied the influence of lag on estimates of Poincaré plot indices for various lengths of beat sequence in a public domain data set (PhysioNet of 29 subjects with CHF and 54 subjects with normal sinus rhythm. Results A curvilinear association was observed between lag and Poincaré plot indices (SD1, SD2, SDLD and SD1/SD2 ratio in normal subjects even for a small sequence of 50 beats (p value for quadratic term 3 × 10-5, 0.002, 3.5 × 10-5 and 0.0003, respectively. This curvilinearity was lost in patients with CHF even after exploring sequences up to 50,000 beats (p values for quadratic term > 0.5. Conclusion Since lagged Poincaré plots incorporate autocovariance information, these analyses provide insights into the autonomic control of heart rate that is influenced by the non-linearity of the signal. The differences in lag-response in CHF patients and normal subjects exist even in the face of the treatment received by the CHF patients.
Cannistraci, Carlo
2013-06-21
Motivation: Most functions within the cell emerge thanks to protein-protein interactions (PPIs), yet experimental determination of PPIs is both expensive and time-consuming. PPI networks present significant levels of noise and incompleteness. Predicting interactions using only PPI-network topology (topological prediction) is difficult but essential when prior biological knowledge is absent or unreliable.Methods: Network embedding emphasizes the relations between network proteins embedded in a low-dimensional space, in which protein pairs that are closer to each other represent good candidate interactions. To achieve network denoising, which boosts prediction performance, we first applied minimum curvilinear embedding (MCE), and then adopted shortest path (SP) in the reduced space to assign likelihood scores to candidate interactions. Furthermore, we introduce (i) a new valid variation of MCE, named non-centred MCE (ncMCE); (ii) two automatic strategies for selecting the appropriate embedding dimension; and (iii) two new randomized procedures for evaluating predictions.Results: We compared our method against several unsupervised and supervisedly tuned embedding approaches and node neighbourhood techniques. Despite its computational simplicity, ncMCE-SP was the overall leader, outperforming the current methods in topological link prediction.Conclusion: Minimum curvilinearity is a valuable non-linear framework that we successfully applied to the embedding of protein networks for the unsupervised prediction of novel PPIs. The rationale for our approach is that biological and evolutionary information is imprinted in the non-linear patterns hidden behind the protein network topology, and can be exploited for predicting new protein links. The predicted PPIs represent good candidates for testing in high-throughput experiments or for exploitation in systems biology tools such as those used for network-based inference and prediction of disease-related functional modules. The
Lee, Hoyee Flora; Gorsuch, Richard L.; Saklofske, Donald H.; Patterson, Colleen A.
2008-01-01
Adult cognitive age differences in the Wechsler Adult Intelligence Scale-III Canadian normative data were curvilinear for most scales and for the Verbal Comprehension (VC), Perceptual Organization (PO), and Working Memory (WM) factors. These showed stable or increasing scores in early adulthood followed by decreasing scores, necessitating a…
Zhang, Xiaomeng; Bartol, Kathryn M.
2010-01-01
Integrating theories addressing attention and activation with creativity literature, we found an inverted U-shaped relationship between creative process engagement and overall job performance among professionals in complex jobs in an information technology firm. Work experience moderated the curvilinear relationship, with low-experience employees…
Claassen, Daniel O.; Dobolyi, David G.; Isaacs, David A.; Roman, Olivia C.; Herb, Joshua; Wylie, Scott A.; Neimat, Joseph S.; Donahue, Manus J.; Hedera, Peter; Zald, David H.; Landman, Bennett A.; Bowman, Aaron B.; Dawant, Benoit M.; Rane, Swati
2016-01-01
Advancing age and disease duration both contribute to cortical thinning in Parkinson’s disease (PD), but the pathological interactions between them are poorly described. This study aims to distinguish patterns of cortical decline determined by advancing age and disease duration in PD. A convenience cohort of 177 consecutive PD patients, identified at the Vanderbilt University Movement Disorders Clinic as part of a clinical evaluation for Deep Brain Stimulation (age: M= 62.0, SD 9.3), completed a standardized clinical assessment, along with structural brain Magnetic Resonance Imaging scan. Age and gender matched controls (n=53) were obtained from the Alzheimer Disease Neuroimaging Initiative and Progressive Parkinson’s Marker Initiative (age: M= 63.4, SD 12.2). Estimated changes in cortical thickness were modeled with advancing age, disease duration, and their interaction. The best-fitting model, linear or curvilinear (2nd, or 3rd order natural spline), was defined using the minimum Akaike Information Criterion, and illustrated on a 3-dimensional brain. Three curvilinear patterns of cortical thinning were identified: early decline, late decline, and early-stable-late. In contrast to healthy controls, the best-fit model for age related changes in PD is curvilinear (early decline), particularly in frontal and precuneus regions. With advancing disease duration, a curvilinear model depicts accelerating decline in the occipital cortex. A significant interaction between advancing age and disease duration is evident in frontal, motor, and posterior parietal areas. Study results support the hypothesis that advancing age and disease duration differentially affect regional cortical thickness and display regional dependent linear and curvilinear patterns of thinning. PMID:27330836
3D Numerical Simulation of Overbank Flow in Non-Orthogonal Curvilinear Coordinates
ZHANG Ming-liang; SHEN Yong-ming; WU Xiu-guang
2005-01-01
The velocity field in meandering compound channels with overbank flow is highly three dimensional. To date, its features have been investigated experimentally and little research has been undertaken to investigate the feasibility of reproducing these velocity fields with computer models. If computer modeling were to prove successful in this context, it could become a useful prediction technique and research tool to enhance our understanding of natural river dynamics. A 3-D k-ε turbulence hydrodynamic model in curvilinear coordinates is established to simulate the overbank flow. The body-fitted coordinate is adopted in the horizontal plane, the part grid is adopted in the vertical direction, and the wall-function method is employed to simulate the bed resistance. The model is applied to the simulation of the meandering channel with straight flood plain banks, and the main velocities and secondary velocities for both the longitudinal and cross sections are presented. Comparison and analysis show that the results of simulation are fit to reflect the results of experiment. These results show the application value of the model to 3D overbank flow.
Shikakhwa, M. S.; Chair, N.
2016-08-01
The Schrödinger Hamiltonian of a spin-less particle as well as the Pauli Hamiltonian with spin-orbit coupling included of a spin one-half particle in electromagnetic fields that are confined to a curved surface embedded in a three-dimensional space spanned by a general Orthogonal Curvilinear Coordinate are constructed. A new approach, based on the physical argument that upon squeezing the particle to the surface by a potential, then it is the physical gauge-covariant kinematical momentum operator (velocity operator) transverse to the surface that should be dropped from the Hamiltonian(s). In both cases, the resulting Hermitian gauge-invariant Hamiltonian on the surface is free from any reference to the component of the vector potential transverse to the surface, and the approach is completely gauge-independent. In particular, for the Pauli Hamiltonian these results are obtained exactly without any further assumptions or approximations. Explicit covariant plug-and-play formulae for the Schrödinger Hamiltonians on the surfaces of a cylinder, a sphere and a torus are derived.
Micro-Grooving and Micro-Threading Tools for Fabricating Curvilinear Features
ADAMS,DAVID P.; VASILE,MICHAEL J.; KRISHNAN,A.S.M.
2000-07-24
This paper presents techniques for fabricating microscopic, curvilinear features in a variety of workpiece materials. Micro-grooving and micro-threading tools having cutting widths as small as 13 {micro}m are made by focused ion beam sputtering and used for ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide to create a number of critically aligned facets. Sputtering produces rake facets of desired angle and cutting edges having radii of curvature equal to 0.4 {micro}m. Clearance for minimizing frictional drag of a tool results from a particular ion beam/target geometry that accounts for the sputter yield dependence on incidence angle. It is believed that geometrically specific cutting tools of this dimension have not been made previously. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close match between tool width and feature size. Microtools are used to machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061 Al cylindrical workplaces. Micro-grooving tools are also used to fabricate sinusoidal cross-section features in planar metal samples.
Talukdar, P.; Steven, M.; Issendorff, F.V.; Trimis, D. [Institute of Fluid Mechanics (LSTM), University of Erlangen-Nuremberg, Cauerstrasse 4, D 91058 Erlangen (Germany)
2005-10-01
The finite volume method of radiation is implemented for complex 3-D problems in order to use it for combined heat transfer problems in connection with CFD codes. The method is applied for a 3-D block structured grid in a radiatively participating medium. The method is implemented in non-orthogonal curvilinear coordinates so that it can handle irregular structure with a body-fitted structured grid. The multiblocking is performed with overlapping blocks to exchange the information between the blocks. Five test problems are considered in this work. In the first problem, present work is validated with the results of the literature. To check the accuracy of multiblocking, a single block is divided into four blocks and results are validated against the results of the single block simulated alone in the second problem. Complicated geometries are considered to show the applicability of the present procedure in the last three problems. Both radiative and non-radiative equilibrium situations are considered along with an absorbing, emitting and scattering medium. (author)
Numerical study of elastic turbulence in a 3D curvilinear micro-channel
Zhang, Hongna; Kunugi, Tomoaki; Li, Fengchen
2012-11-01
Elastic turbulence is an intriguing phenomenon of viscoelastic fluid flow, and dominated by the strong nonlinear elasticity due to the existence of flexible microstructures. It implies the possibility to generate a turbulent state (so-called an elastic turbulence) in the micro-scale devices by introducing the viscoelastic fluids, which could significantly enhance the mixing efficiency therein. Several experiments have been carried out to study its characteristics and underlying physics. However, the difficulty in measuring the flow information and behaviors of the microstructures, especially in the cross section normal to the mean flow direction, limits our current understanding and controlling. In the present study, the nondimensionalization method in which the characteristic velocity is defined as the ratio of the solution viscosity to the width of the channel was adopted to simulate the elastic turbulence in the micro-scale devices. And the elastic turbulent flow was obtained numerically in the 3D curvilinear micro-channel. Therein, the characteristics of the velocity field and polymer's behavior are discussed. Moreover, the energy transfer between the kinetic energy and the polymer's elastic energy is also investigated to understand its physical mechanism. Supported by the Japan Society for the Promotion of Science research fellowship and the Ministry of Education, Culture, Sports, Science and Technology via `Energy Science in the Age of Global Warming' of Global Center of Excellence (G-COE) program (J-051).
Ahmet Taylan Yazici
2012-01-01
Full Text Available Objective: To evaluate the 2-year outcomes of phacoemulsification combined with primary posterior curvilinear capsulorhexis (PPCC in adults. Materials and Methods: In this retrospective case series, 93 eyes of 91 patients with bilateral age-related cataract who underwent phacoemulsification combined with PPCC were evaluated. The study included cases due to postoperative residual posterior capsule opacification despite careful polishing. Data were evaluated on preoperative and postoperative best corrected visual acuity (CDVA (Snellen acuity, slit-lamp biomicroscopy and intraocular pressure (IOP measurement. Perioperative and postoperative complications were also recorded. Results: The mean follow-up was 24.9 ±13.5 months (range, 12-53 months. At the last visit, 87.1% of the eyes had CDVA ≥ 20/40 and 58% had ≥ 20/25. Posterior capsular opacification (PCO occurred in 2 (2.2% of patients. No serious complications such as retinal detachment and endophthalmitis were observed during follow-up. Conclusions: Cataract surgery combined with PPCC is a safe procedure with a low rate of complications over the long term. This procedure reduced the necessity of Nd:YAG laser capsulotomy in adults with postoperative residual posterior capsule opacification despite careful polishing.
Pravir Dutt; Satyendra Tomar
2003-11-01
In this paper we show that the ℎ- spectral element method developed in [3,8,9] applies to elliptic problems in curvilinear polygons with mixed Neumann and Dirichlet boundary conditions provided that the Babuska–Brezzi inf-sup conditions are satisfied. We establish basic stability estimates for a non-conforming ℎ- spectral element method which allows for simultaneous mesh refinement and variable polynomial degree. The spectral element functions are non-conforming if the boundary conditions are Dirichlet. For problems with mixed boundary conditions they are continuous only at the vertices of the elements. We obtain a stability estimate when the spectral element functions vanish at the vertices of the elements, which is needed for parallelizing the numerical scheme. Finally, we indicate how the mesh refinement strategy and choice of polynomial degree depends on the regularity of the coefficients of the differential operator, smoothness of the sides of the polygon and the regularity of the data to obtain the maximum accuracy achievable.
Endeve, Eirik; Xing, Yulong; Mezzacappa, Anthony
2014-01-01
We extend the positivity-preserving method of Zhang & Shu (2010, JCP, 229, 3091-3120) to simulate the advection of neutral particles in phase space using curvilinear coordinates. The ability to utilize these coordinates is important for non-equilibrium transport problems in general relativity and also in science and engineering applications with specific geometries. The method achieves high-order accuracy using Discontinuous Galerkin (DG) discretization of phase space and strong stability-preserving, Runge-Kutta (SSP-RK) time integration. Special care in taken to ensure that the method preserves strict bounds for the phase space distribution function $f$; i.e., $f\\in[0,1]$. The combination of suitable CFL conditions and the use of the high-order limiter proposed in Zhang & Shu (2010) is sufficient to ensure positivity of the distribution function. However, to ensure that the distribution function satisfies the upper bound, the discretization must, in addition, preserve the divergence-free property of ...
Andrews, Naomi C Z; Hanish, Laura D; Updegraff, Kimberly A; Martin, Carol Lynn; Santos, Carlos E
2016-09-01
Are early adolescent victims of peer-directed aggression youth who hold prominent positions in the social hierarchy or those who are socially marginalized? The present study tackles this question by testing for linear and curvilinear relationships between social network prestige and physical and relational forms of peer victimization for boys and girls. Participants were 952 middle schoolers (age range = 10-14 years; 49.9 % girls; 44 % Latino). Participants nominated victims and friends; friendship nominations were used to calculate social network prestige. Both hypotheses received support, with variation by gender. Girls high in social network prestige were highly victimized. For boys, those both high and low in social network prestige were highly victimized, whereas those at mid-levels of social network prestige were low in victimization. The findings are discussed in relation to a social dominance model of peer-directed aggression, and the practical implications are discussed in relation to protecting youth who are frequent targets of peer victimization. PMID:26920566
Shikakhwa, M. S.; Chair, N.
2016-05-01
The Hermitian Hamiltonian of a spin one-half particle with spin-orbit coupling (SOC) confined to a surface that is embedded in a three-dimensional space spanned by a general Orthogonal Curvilinear Coordinate (OCC) is constructed. A gauge field formalism, where the SOC is expressed as a non-Abelian SU (2) gauge field is used. A new practical approach, based on the physical argument that upon confining the particle to the surface by a potential, then it is the physical Hermitian momentum operator transverse to the surface, rather than just the derivative with respect to the transverse coordinate that should be dropped from the Hamiltonian. Doing so, it is shown that the Hermitian Hamiltonian for SOC is obtained with the geometric potential and the geometric kinetic energy terms emerging naturally. The geometric potential is shown to represent a coupling between the transverse component of the gauge field and the mean curvature of the surface that replaces the coupling between the transverse momentum and the gauge field. The most general Hermitian Hamiltonian with linear SOC on a general surface embedded in any 3D OCC system is reported. Explicit plug-and-play formulae for this Hamiltonian on the surfaces of a cylinder, a sphere and a torus are given. The formalism is applied to the Rashba SOC in three dimensions (3D RSOC) and the explicit expressions for the surface Hamiltonians on these three geometries are worked out.
Bimurzaev, S B
2002-01-01
Movement equations of two-dimensional electron mirrors with curvilinear axial trajectory have been reduced to form similar for such mirrors with rectilinear axial trajectory by introduction of effective potentials. On the basis of this analogy the general expressions to within sizes of the second order trifle, describing time-of-flight and equation of a trajectory in an average plane in two-dimensional electronic mirrors with curvilinear by an axial trajectory are received. The space and time-of-flight focusing conditions and also conditions of elimination of separate kind aberration are determined. By numerical accounts the condition stigmatic focusing elimination spherical aberration of the second order in two and three-electrode mirror electrostatic power analyser are found which electrodes serve pairs of parallel plates divided by direct cracks. The time-of-flight focusing condition up to the second order inclusive for a three-electrode flat mirror are found also. (author)
Melaaen, M. C.
1992-02-01
Tensor calculus is presently employed to furnish both necessary coordinate and velocity transformations in the present use of two different finite-volume methods for discretization of conservation equations in 3D curvilinear nonorthogonal coordinates. While one method is based on the nonstaggered grid arrangement and employs Cartesian velocity components as dependent variables in the momentum equations, the other combines a staggered grid arrangement with physical covariant velocity projections in a locally fixed coordinate system. In the second part of this work, a comparative evaluation of the two methods indicates that while results of comparable accuracy are achieved after a similar number of iterations, the staggered method may be recommended for curvilinear nonorthogonal coordinate problems due to its reduced memory and computational requirements.
Tanskanen, Jussi; Taipale, Sakari; Anttila, Timo
2016-01-01
Previous studies measuring different aspects of the quality of life have, as a rule, presumed linear relationships between a dependent variable and its predictors. This article utilizes non-parametric statistical methodology to explore curvilinear relations between work engagement and its main predictors: job demands, job control and social support. Firstly, the study examines what additional information non-linear modeling can reveal regarding the relationship between work eng...
The Bay of Bengal is surrounded by the coasts from all sides except in the south where there is open sea. The coasts are curvilinear in nature and the bending is very high along the coast of Bangladesh. Moreover, there are many small and big islands in the offshore region of the Bangladesh coast. In order to incorporate the island boundaries and the coastlines properly in the numerical scheme it is necessary to consider a very fine grid resolution along the coastal belts, whereas this is unnecessary away from the coasts. Consideration of very fine resolution involves, unnecessarily, more memory and more CPU time in the solution process and invites problem of numerical instability. In hydrodynamic models for coastal seas, bays, and estuaries the use of boundary-fitted curvilinear grids not only makes the model grids fit to the coastline, but also make the finite difference scheme simple and more accurate. In this study we use the boundary-fitted curvilinear grids where the complete boundary of the analysis area is represented by four curves and they are defined by four functions. Based on them, the four boundaries of each island are represented approximately by two generalized functions. Appropriate transformations of independent coordinates are considered so that the curvilinear physical domain transforms to a square one and also each island boundary transforms to a rectangle within this square domain. The vertically integrated shallow water equations are transformed to the new space domain. In the transformed domain, the regular explicit finite difference scheme is used to solve the shallow water equations. The model is applied to compute the water levels due to astronomical tide and surges associated with a few tropical storms that hit the coast of Bangladesh. (author)
Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis
2008-08-10
The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A Numerical Method for Solving the 3D Unsteady Incompressible Navier-Stokes Equations in Curvilinear Domains with Complex Immersed Boundaries, Journal of Computational Physics 225 (2007) 1782-1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions unconditionally unstable iteration schemes result even when strong coupling FSI is employed. For such cases, however, combining the strong-coupling iteration with under-relaxation in conjunction with the Aitken's acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the FSI
Zhang, Haichong K.; Aalamifar, Fereshteh; Boctor, Emad M.
2016-04-01
Synthetic aperture for ultrasound is a technique utilizing a wide aperture in both transmit and receive to enhance the ultrasound image quality. The limitation of synthetic aperture is the maximum available aperture size limit determined by the physical size of ultrasound probe. We propose Synthetic-Tracked Aperture Ultrasound (STRATUS) imaging system to overcome the limitation by extending the beamforming aperture size through ultrasound probe tracking. With a setup involving a robotic arm, the ultrasound probe is moved using the robotic arm, while the positions on a scanning trajectory are tracked in real-time. Data from each pose are synthesized to construct a high resolution image. In previous studies, we have demonstrated the feasibility through phantom experiments. However, various additional factors such as real-time data collection or motion artifacts should be taken into account when the in vivo target becomes the subject. In this work, we build a robot-based STRATUS imaging system with continuous data collection capability considering the practical implementation. A curvilinear array is used instead of a linear array to benefit from its wider capture angle. We scanned human forearms under two scenarios: one submerged the arm in the water tank under 10 cm depth, and the other directly scanned the arm from the surface. The image contrast improved 5.51 dB, and 9.96 dB for the underwater scan and the direct scan, respectively. The result indicates the practical feasibility of STRATUS imaging system, and the technique can be potentially applied to the wide range of human body.
Chun-Tao Zhang; Yuan He; Jun Jia
2016-01-01
AIM:To discuss the application of trypan blue before continuous curvilinear capsulorhexis(CCC)during the surgery for all white or over ripe stage cataract. METHODS:Forty-two eyes in 42 patients with cataract in all white or over ripe stage were selected. During the operations, 0.2mL trypan blue(0.6mg/mL)was injected into the anterior chambers of all the 42 eyes. The anterior capsule was stained to light blue. Then the CCC was conducted. The density of corneal endothelial cells and the percent...
Md. Fazlul Karim
2007-01-01
Full Text Available The west coast of Peninsular Malaysia and Thailand is curvilinear in nature and the bending is especially high along the coast of South Thailand. In hydrodynamic models for coastal seas, bays and estuaries, the use of boundary-fitted curvilinear grids not only makes the model grids fit well with the coastline and bathymetry, but also makes the finite difference scheme simple. In this study, a shallow water model is developed using boundary fitted curvilinear mesh. The west coast of Peninsular Malaysia and Thailand and the western open boundary are represented by two curves, which are defined by two functions. The other two boundaries are considered as straight lines along the open sea. Appropriate transformations of independent coordinates are applied so that the curvilinear physical domain transforms to a rectangular domain and the curvilinear grid system transforms to a rectangular system. The depth averaged shallow water equations and the boundary conditions are transformed to the new space domain and these are solved in the rectangular mesh of the transformed space. The model is applied to compute some aspects of the tsunami associated with the 26 December 2004 Indonesian tsunami along the coastal belts of Penang in Malaysia and Phuket in Thailand. The computed results along the coastal belts are in excellent agreement with the observe data available in the USGS website.
Yuan, Xuefei
2012-07-01
Numerical simulations of the four-field extended magnetohydrodynamics (MHD) equations with hyper-resistivity terms present a difficult challenge because of demanding spatial resolution requirements. A time-dependent sequence of . r-refinement adaptive grids obtained from solving a single Monge-Ampère (MA) equation addresses the high-resolution requirements near the . x-point for numerical simulation of the magnetic reconnection problem. The MHD equations are transformed from Cartesian coordinates to solution-defined curvilinear coordinates. After the application of an implicit scheme to the time-dependent problem, the parallel Newton-Krylov-Schwarz (NKS) algorithm is used to solve the system at each time step. Convergence and accuracy studies show that the curvilinear solution requires less computational effort than a pure Cartesian treatment. This is due both to the more optimal placement of the grid points and to the improved convergence of the implicit solver, nonlinearly and linearly. The latter effect, which is significant (more than an order of magnitude in number of inner linear iterations for equivalent accuracy), does not yet seem to be widely appreciated. © 2012 Elsevier Inc.
Vaillon, R.; Lallemand, M.; Lemonnier, D. [Ecole Nationale Superieure de Mecanique et d`Aerotechnique (ENSMA), 86 - Poitiers (France)
1996-12-31
The method of discrete ordinates, which is more and more widely used in radiant heat transfer studies, is mainly developed in Cartesian, (r,z) and (r,{Theta}) cylindrical, and spherical coordinates. In this study, the approach of this method is performed in orthogonal curvilinear coordinates: determination of the radiant heat transfer equation, treatment of the angular redistribution terms, numerical procedure. Some examples of application are described in 2-D geometry defined in curvilinear coordinates along a curve and at the thermal equilibrium. A comparison is made with the discrete ordinates method in association with the finite-volumes method in non structured mesh. (J.S.) 27 refs.
Höller, Harald
2012-01-01
A generalization of implicit conservative numerics to multiple dimensions requires advanced concepts of tensor analysis and differential geometry and hence a more thorough dedication to mathematical fundamentals than maybe expected at first glance. Hence we begin to discuss fundamental mathematics and physics of RHD with special focus on differential geometric consistency and study numerical methods for nonlinear conservation laws to gain a solid definition of the term conservative. The efforts in tensor analysis will be needed when applying Vinokurs theorem to gain the strong conservation form for conservation laws in general curvilinear coordinates. Moreover, it will be required to slightly reformulate the artificial viscosity for such nonlinear coordinates. Astronomical objects are characterized by fast flows and high propagation speeds on the one hand but astronomical length and time scales on the other hand. Implicit numerical schemes are not affected by the Courant Friedrichs Levy condition which limits...
Khosronejad, Ali; Kang, Seokkoo; Borazjani, Iman; Sotiropoulos, Fotis
2011-07-01
The fluid-structure interaction curvilinear immersed boundary (FSI-CURVIB) numerical method of Borazjani et al. [3] is extended to simulate coupled flow and sediment transport phenomena in turbulent open-channel flows. The mobile channel bed is discretized with an unstructured triangular mesh and is treated as a sharp-interface immersed boundary embedded in a background curvilinear mesh used to discretize the general channel outline. The unsteady Reynolds-averaged Navier-Stokes (URANS) equations closed with the k - ω turbulence model are solved numerically on a hybrid staggered/non-staggered grid using a second-order accurate fractional step method. The bed deformation is calculated by solving the sediment continuity equation in the bed-load layer using an unstructured, finite-volume formulation that is consistent with the CURVIB framework. Both the first-order upwind and the higher-order hybrid GAMMA schemes [12] are implemented to discretize the bed-load flux gradients and their relative accuracy is evaluated through a systematic grid refinement study. The GAMMA scheme is employed in conjunction with a sand-slide algorithm for limiting the bed slope at locations where the material angle of repose condition is violated. The flow and bed deformation equations are coupled using the partitioned loose-coupling FSI-CURVIB approach [3]. The hydrodynamic module of the method is validated by applying it to simulate the flow in an 180° open-channel bend with fixed bed. To demonstrate the ability of the model to simulate bed morphodynamics and evaluate its accuracy, we apply it to calculate turbulent flow through two mobile-bed open channels, with 90° and 135° bends, respectively, for which experimental measurements are available.
Hofmans, Joeri; Debusscher, Jonas; Dóci, Edina; Spanouli, Andromachi; De Fruyt, Filip
2015-01-01
Whereas several studies have demonstrated that core self-evaluations (CSE)-or one's appraisals about one's own self-worth, capabilities, and competences-relate to job outcomes, less is known about the mechanisms underlying these relationships. In the present study, we address this issue by examining the role of within- and between-person variation in CSE in the relationship between work pressure and task performance. We hypothesized that (a) work pressure relates to task performance in a curvilinear way, (b) state CSE mediates the curvilinear relationship between work pressure and task performance, and (c) the relationship between work pressure and state CSE is moderated by trait CSE. Our hypotheses were tested via a 10-day daily diary study with 55 employees in which trait CSE was measured at baseline, while work pressure, task performance, and state CSE were assessed on a daily basis. Bayesian multilevel path analysis showed that work pressure affects task performance via state CSE, with state CSE increasing as long as the employee feels that (s)he is able to handle the work pressure, while it decreases when the level of work pressure exceeds the employees' coping abilities. Moreover, we found that for people low on trait CSE, the depleting effect of work pressure via state CSE happens for low levels of work pressure, while for people high in trait CSE the depleting effect is located at high levels of work pressure. Together, our findings suggest that the impact of work pressure on task performance is driven by a complex interplay of between- and within-person differences in CSE. PMID:26579053
Kumar, D.
1980-01-01
The computer program AFTBDY generates a body fitted curvilinear coordinate system for a wedge curved after body. This wedge curved after body is being used in an experimental program. The coordinate system generated by AFTBDY is used to solve 3D compressible N.S. equations. The coordinate system in the physical plane is a cartesian x,y,z system, whereas, in the transformed plane a rectangular xi, eta, zeta system is used. The coordinate system generated is such that in the transformed plane coordinate spacing in the xi, eta, zeta direction is constant and equal to unity. The physical plane coordinate lines in the different regions are clustered heavily or sparsely depending on the regions where physical quantities to be solved for by the N.S. equations have high or low gradients. The coordinate distribution in the physical plane is such that x stays constant in eta and zeta direction, whereas, z stays constant in xi and eta direction. The desired distribution in x and z is input to the program. Consequently, only the y-coordinate is solved for by the program AFTBDY.
Wongwathanarat, Annop; Müller, Ewald
2016-01-01
We present a new fourth-order finite-volume hydrodynamics code named Apsara. The code employs the high-order finite-volume method for mapped coordinates developed by Colella et al. (2011) with extensions for non-linear hyperbolic conservation laws by McCorquodale & Colella (2011) and Guzik et al. (2012). Using the mapped-grid technique Apsara can handle arbitrary structured curvilinear meshes in three spatial dimensions. The code has successfully passed several hydrodynamic test problems including the advection of a Gaussian density profile and a non-linear vortex, as well as the propagation of linear acoustic waves. For these test problems Apsara produces fourth-order accurate results in case of smooth grid mappings. The order of accuracy is reduced to first-order when using the non-smooth circular grid mapping of Calhoun et al. (2008). When applying the high-order method by McCorquodale & Colella (2011) to simulations of low-Mach number flows, e.g. the Gresho vortex and the Taylor-Green vortex, we d...
Khil, Eun Kyung; Lee, A. Leum; Chang, Kee-Hyun; Yun, Tae Jin; Hong, Hyun Sook
2015-01-01
Abstract Lung cancer is one of the most common neoplasms to appear leptomeningeal metastasis (LM). Contrast-enhanced magnetic resonance imaging (MRI) is better diagnostic choice for LM and usually shows focal nodular or diffuse linear enhancement on the leptomeninges along the sulci and tentorium in the brain. We experienced atypical 2 cases of lung cancer in patients who showed unusual brain MRI finding of symmetrical curvilinear or band-like, nonenhancing cytotoxic edema along the surface o...
Quantization in curvilinear coordinates
The general covariant quantization method based on the equivalence principle is proposed. According to this method, it is found that an extra term: -1/3R appears in the Klein-Gordon equation. As a result, the effective mass of an electron, for example, will increase by the ratio of 10-35 at the center of a neutron star. (author)
Ge, Liang; Sotiropoulos, Fotis
2007-08-01
A novel numerical method is developed that integrates boundary-conforming grids with a sharp interface, immersed boundary methodology. The method is intended for simulating internal flows containing complex, moving immersed boundaries such as those encountered in several cardiovascular applications. The background domain (e.g the empty aorta) is discretized efficiently with a curvilinear boundary-fitted mesh while the complex moving immersed boundary (say a prosthetic heart valve) is treated with the sharp-interface, hybrid Cartesian/immersed-boundary approach of Gilmanov and Sotiropoulos [1]. To facilitate the implementation of this novel modeling paradigm in complex flow simulations, an accurate and efficient numerical method is developed for solving the unsteady, incompressible Navier-Stokes equations in generalized curvilinear coordinates. The method employs a novel, fully-curvilinear staggered grid discretization approach, which does not require either the explicit evaluation of the Christoffel symbols or the discretization of all three momentum equations at cell interfaces as done in previous formulations. The equations are integrated in time using an efficient, second-order accurate fractional step methodology coupled with a Jacobian-free, Newton-Krylov solver for the momentum equations and a GMRES solver enhanced with multigrid as preconditioner for the Poisson equation. Several numerical experiments are carried out on fine computational meshes to demonstrate the accuracy and efficiency of the proposed method for standard benchmark problems as well as for unsteady, pulsatile flow through a curved, pipe bend. To demonstrate the ability of the method to simulate flows with complex, moving immersed boundaries we apply it to calculate pulsatile, physiological flow through a mechanical, bileaflet heart valve mounted in a model straight aorta with an anatomical-like triple sinus. PMID:19194533
Byun, Jaeseung; Bodony, Daniel; Pantano, Carlos
2014-11-01
Improved order-of-accuracy discretizations often require careful consideration of their numerical stability. We report on new high-order finite difference schemes using Summation-By-Parts (SBP) operators along with the Simultaneous-Approximation-Terms (SAT) boundary condition treatment for first and second-order spatial derivatives with variable coefficients. In particular, we present a highly accurate operator for SBP-SAT-based approximations of second-order derivatives with variable coefficients for Dirichlet and Neumann boundary conditions. These terms are responsible for approximating the physical dissipation of kinetic and thermal energy in a simulation, and contain grid metrics when the grid is curvilinear. Analysis using the Laplace transform method shows that strong stability is ensured with Dirichlet boundary conditions while weaker stability is obtained for Neumann boundary conditions. Furthermore, the benefits of the scheme is shown in the direct numerical simulation (DNS) of a Mach 1.5 compressible turbulent supersonic jet using curvilinear grids and skew-symmetric discretization. Particularly, we show that the improved methods allow minimization of the numerical filter often employed in these simulations and we discuss the qualities of the simulation.
孙建民; 孙良智; 苏保辉; 李忠; 徐晓梅; 刘美秀
2012-01-01
[Objective] To discuss the clinical curative effect of minimal invasion surgery for heel pain in elderly patients (age ≥60 years) with calcaneal tubercle osteophyte. [Methods] From July 2000 to July 2010, the surgical methods and clinical curative effect were analyzed in 159 cases ( 173 feet) of heel pain with calcaneal lubercle osteophyle. According to the Maryland scoring system, all the cases were < 50 scores before surgery. Minimally invasive removal of osteophytes, the release of plantar fascia insertion and bursa surgery were operated in 57 feet (minimal invasion group) , while other 47 feet received open surgery ( open group) . [ Results] A total of 93 cases (104 feet) obtained a mean of 19 months follow up. In minimal invasion group, the pain was completely relieved without walking effect in 55 feet. Other 2 feet also improved pain relief significantly, but the pain was residual after severe activity, which can be relieved by rest. In open group, the pain was completely relieved without walking effect in 45 feet. One foot improved pain relief significantly, but the pain was residual after severe activity, which can be relieved by rest. One foot suffered from scarring pain for six months, which disappeared after the softening of the scar. [Conclusion] For the heel pain with calcaneal tubercle osteophyte, it can obtain good clinical curative effect by releasing the plantar fascia insertion and removing the osteophytes and bursa both in minimal invasion surgery and open surgery. Compared with the open surgery, the minimal invasion surgery can be acceptable easily for ihe less invasion and faster recovery.%[目的]探讨老年(年龄≥60岁)跟骨结节骨赘型跟痛症微创治疗的临床疗效.[方法]对2000年7月～2010年7月本院治疗的159例(173足)跟骨结节骨赘型跟痛症老年患者的手术方式及疗效进行分析.根据Maryland 评分患者均＜50分,其中82足(微创组)患者接受了微创骨赘切除、跖腱膜止
Changala, P Bryan
2016-01-01
We present a perturbative method for ab initio calculations of rotational and rovibrational effective Hamiltonians of both rigid and non-rigid molecules. Our approach is based on a curvilinear implementation of second order vibrational M{\\o}ller-Plesset perturbation theory (VMP2) extended to include rotational effects via a second order contact transformation. Though more expensive, this approach is significantly more accurate than standard second order vibrational perturbation theory (VPT2) for systems that are poorly described to zeroth order by rectilinear normal mode harmonic oscillators. We apply this method and demonstrate its accuracy on two molecules: Si$_2$C, a quasilinear triatomic with significant bending anharmonicity, and CH$_3$NO$_2$, which contains a completely unhindered methyl rotor. In addition to these two examples, we discuss several key technical aspects of the method, including an efficient implementation of Eckart and quasi-Eckart frame embedding that does not rely on numerical finite d...
王兴武; 陆建猛; 俞武良; 韦勇力; 方明
2014-01-01
目的 观察单纯采用椎体骨赘填充椎体护架(Cage)行颈前路椎体间融合的融合率.方法 2010年1月至2012年7月,对81例行颈前路椎间盘切除减压、融合、钛板内固定手术的患者单纯采集手术间隙椎体前后缘的骨赘填充Cage.男52例,女29例;年龄55～78岁,平均64.1岁,单节段手术46例,双节段35例.术后3个月、6个月和1年复查颈椎X线片和CT观察重建融合效果.结果 术后3个月总融合率为76.5％(62/81),单节段融合率为78.3％(36/46),双节段融合率为74.3％％(26/35).术后6个月总融合率为93.8％(76/81),单节段融合率为95.7％(44/46),双节段融合率为91.4％(32/35).术后1年总融合率为100％(81/81).不同节段手术的融合率差异无统计学意义. 结论 对颈前路单节段或双节段手术,以骨赘填充Cage进行椎体间融合可获得满意的融合率.%Objective To observe the fusion rate by using cage filled with osteophyte in anterior cervical disectomy and fusion.Methods From January 2010 to July 2012,81 patients receiving anterior cervical disectomy and spine fusion underwent treatment with cages containing exclusively autologous osteophyte collected from both anterior and posterior vertebral edges adjacent to the intervertebral space.There were 52 males and 29 females,aged from 55 to 78 years,average 64.1 years in this study.46 patients received one-level fusion,and 35 patients received two-level fusion respectively.Patients were followed up at 3 months,6 months and 1 year after operation.The fusion was evaluated by X-ray film and reconstructive CT.Results The total fusion rate after 3 months of operation was 76.5％ (62/81),the one-level and two-level fusion rate were 78.3％ (36/46) and 74.3％ (26/35),respectively.The total fusion rate after 6 months of operation was 93.8％ (76/81),the one-level and two-level fusion rate were 95.7％ (44/46) and 91.4％ (32/35),respectively.The total fusion rate was 100％ (81/81) after 1 year of
Schou, Morten; Gustafsson, Finn; Corell, Pernille; Kistorp, Caroline N; Kjaer, Andreas; Hildebrandt, Per R
2007-01-01
BACKGROUND: N-terminal pro-brain natriuretic peptide (NT-proBNP) carries prognostic information in patients with chronic heart failure and predicts risk for mortality and cardiovascular events. It is unknown whether NT-proBNP predicts risk for hospitalization for any cause. Furthermore, a...... doubling NT-proBNP on adjusted hazard ratios was 1.56 (95% CI 1.32-1.85) for mortality and 1.19 (95% CI 1.09-1.31) for hospitalization. We observed a curvilinear relationship between NT-proBNP and risk for mortality and hospitalization in the whole range of NT-proBNP. CONCLUSIONS: N-terminal pro-brain...... natriuretic peptide predicts risk for hospitalization and mortality. A simple algorithm indicates that every time NT-proBNP is doubled, estimated hazard ratio for death increases by a factor of 1.56 (56%) and by a factor of 1.19 (19%) for hospitalization. Finally, the relationship between NT-proBNP and risk...
Bruno, Oscar
2015-01-01
This paper introduces alternating-direction implicit (ADI) solvers of higher order of time-accuracy (orders two to six) for the compressible Navier-Stokes equations in two- and three-dimensional curvilinear domains. The higher-order accuracy in time results from 1) An application of the backward differentiation formulae time-stepping algorithm (BDF) in conjunction with 2) A BDF-like extrapolation technique for certain components of the nonlinear terms (which makes use of nonlinear solves unnecessary), as well as 3) A novel application of the Douglas-Gunn splitting (which greatly facilitates handling of boundary conditions while preserving higher-order accuracy in time). As suggested by our theoretical analysis of the algorithms for a variety of special cases, an extensive set of numerical experiments clearly indicate that all of the BDF-based ADI algorithms proposed in this paper are "quasi-unconditionally stable" in the following sense: each algorithm is stable for all couples $(h,\\Delta t)$ of spatial and t...
Bruno, Oscar P.; Cubillos, Max
2016-02-01
This paper introduces alternating-direction implicit (ADI) solvers of higher order of time-accuracy (orders two to six) for the compressible Navier-Stokes equations in two- and three-dimensional curvilinear domains. The higher-order accuracy in time results from 1) An application of the backward differentiation formulae time-stepping algorithm (BDF) in conjunction with 2) A BDF-like extrapolation technique for certain components of the nonlinear terms (which makes use of nonlinear solves unnecessary), as well as 3) A novel application of the Douglas-Gunn splitting (which greatly facilitates handling of boundary conditions while preserving higher-order accuracy in time). As suggested by our theoretical analysis of the algorithms for a variety of special cases, an extensive set of numerical experiments clearly indicate that all of the BDF-based ADI algorithms proposed in this paper are "quasi-unconditionally stable" in the following sense: each algorithm is stable for all couples (h , Δt)of spatial and temporal mesh sizes in a problem-dependent rectangular neighborhood of the form (0 ,Mh) × (0 ,Mt). In other words, for each fixed value of Δt below a certain threshold, the Navier-Stokes solvers presented in this paper are stable for arbitrarily small spatial mesh-sizes. The second-order formulation has further been rigorously shown to be unconditionally stable for linear hyperbolic and parabolic equations in two-dimensional space. Although implicit ADI solvers for the Navier-Stokes equations with nominal second-order of temporal accuracy have been proposed in the past, the algorithms presented in this paper are the first ADI-based Navier-Stokes solvers for which second-order or better accuracy has been verified in practice under non-trivial (non-periodic) boundary conditions.
Momentum Deposition in Curvilinear Coordinates
Cleveland, Mathew Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lowrie, Robert Byron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rockefeller, Gabriel M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thompson, Kelly Glen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wollaber, Allan Benton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-08-03
The momentum imparted into a material by thermal radiation deposition is an important physical process in astrophysics and inertial confinement fusion (ICF) simulations. In recent work we presented a new method of evaluating momentum deposition that relies on the combination of a time-averaged approximation and a numerical integration scheme. This approach robustly and efficiently evaluates the momentum deposition in spherical geometry. Future work will look to extend this approach to 2D cylindrical geometries.
刘宁; 孙宇
2010-01-01
Objective To observe the short-term fusion rate of using osteophyte filled cage in ante-rior cervical disectomy and fusion. Methods From May 2007 to May 2009, 103 patients receiving anterior cervical disectomy, spine fusion by different surgeons were performed with cages containing exclusively au-tologous osteophyte collected from both anterior and posterior vertebral edges adjacent to the intervertebral space. There are 69 males, 34 females, from 25 to 77 years of age, average 53.6 years. 60 patients received one level fusion. 33 and 10 patients received two-level and three-level fusion respectively. Patients were re-viewed 3 months after operation and fusion was evaluated by X-ray film, reconstructive CT and MR. Results 1. Only 1.9% (2/103) of patients' X-ray films indicate non-fusion (internal fixation failure) while 31.7% (32/ 103) of patients' CT and 30.1% (31/103) of patients' MR indicate non-fusion or being confusing to make a diagnosis. 2. The diagnostic coherence between CT and MR as to evaluate fusion is good (kappa=0.686, P= 0.00). 3. The total fusion rate was 77.7%(80/103) while the highest fusion rate achieved by single surgeon was 90%(18/20). The total one level fusion rate was 80%(48/60) while the highest rate by single surgeon was 88.2%(15/17). The total two-level fusion rate was 78.6%(26/33) while the highest rate by single sur-geon was 90%(9/10). The total three-level fusion rate was 60%(60/100) while the highest rate by single surgeon was 100%(3/3). No statistic significant difference in fusion rate was found between any two of the three groups. Conclusion The method of using osteophyte filled cage can acquire ideal short-term fusion rate in one and two-level anterior cervical disectomy, fusion and plate fixation.%目的 观察单纯采用椎体骨赘填充cage行颈前路椎体间融合的短期融合率.方法 2007年5月至2009年5月,不同医生对103例行颈前路椎间盘切除减压、融合、钛板内固定手术的患者单纯采集
Particle simulation in curvilinear coordinate systems
We present methods for particle simulation of plasmas in a nearly arbitrary coordinate metric and describe a toroidal electrostatic simulation code that evolved from this effort. A Mercier-type coordinate system is used, with a nonuniform radial grid for improved cross-field resolution. A fast iterative method for solving the Poisson equation is employed, and the interpolation/filtering technique shown to be momentum and energy conserving in the continuum limit. Lorentz ion and drift electron species are used. The code has been thoroughly tested for its reproduction of linear and nonlinear physics, and has been applied to the toroidal drift wave problem and its impact on anomalous transport in tokamaks. 40 refs., 10 figs., 1 tab
Optimizing the geometrical accuracy of curvilinear meshes
Toulorge, Thomas; Remacle, Jean-François
2015-01-01
This paper presents a method to generate valid high order meshes with optimized geometrical accuracy. The high order meshing procedure starts with a linear mesh, that is subsequently curved without taking care of the validity of the high order elements. An optimization procedure is then used to both untangle invalid elements and optimize the geometrical accuracy of the mesh. Standard measures of the distance between curves are considered to evaluate the geometrical accuracy in planar two-dimensional meshes, but they prove computationally too costly for optimization purposes. A fast estimate of the geometrical accuracy, based on Taylor expansions of the curves, is introduced. An unconstrained optimization procedure based on this estimate is shown to yield significant improvements in the geometrical accuracy of high order meshes, as measured by the standard Haudorff distance between the geometrical model and the mesh. Several examples illustrate the beneficial impact of this method on CFD solutions, with a part...
汪建军; 许才军
2009-01-01
本文建立了顾及地球扁率和局部切标架随点变化特性的椭球坐标系下的刚体运动模型和块体运动与应变模型,以及球坐标系下顾及局部切标架随点变化特性的严密的块体运动与应变模型,分析了球坐标系下块体运动与应变模型及椭球坐标系下的块体运动与应变模型间的差异;通过计算具体讨论了地球扁率和曲线坐标系的局部切标架随点变化特性对欧拉矢量与应变张量的影响.结果表明:地球扁率对刚体欧拉矢量和应变参数的影响甚小,具体计算时可以不予考虑,但曲线坐标系的局部切标架随点变化特性对两者的影响较大,在建模过程中需要顾及,常用的Savage模型需要修正.%We present rigid block motion model and strain rate model in a geodetic coordinate system as well as those in a spherical coordinate system under the framework of tensor analysis. Both eccentricity and local tangential moving frame are now considered in these models,which is not the case for previous modeling. To explore the effects of these two geometrical characteristics,we investigate differences in parameters such as Euler pole and strain rate tensor by employing these models to invert them. Our results show that the eccentricity has minor effects on determining Euler pole and strain rate tensor,indicating that it is reasonable not to consider crustal motion and deformation models in a geodetic coordinate system. On the contrary,the local tangential moving frame plays a big role in changing both of them,meaning that the local frame of velocity being different at each observation site should be taken account of when one builds up strain model in a curvilinear coordinate system. Accordingly,the conventional Savage's crustal deformation model should be refurnished.
孙健敏; 陆欣欣; 孙嘉卿
2015-01-01
As a type of important job resource , perceived organizational support has been identified as a salient antecedent of work engagement .However , the extant literature has ignored that with the norm of reciprocity as its core tenet , perceived organization-al support requires reciprocation from the recipients .Then, below a certain point, employees who perceive organizational support are expected to reciprocate by performing extra-role behavior , which reduces their engagement in assigned work .Based on Job-Demand Resource model and social exchange theory , we argue that there may be U-shaped relationship between perceived organi-zational support and work engagement .Moreover, the extent to which individuals are engaged in extra-role performance is pro-foundly shaped by their affective commitment with the organization .Therefore, we propose that affective commitment moderates the curvilinear relationship between perceived organizational support and work engagement . We collected data among 302 employees with diverse positions in securities industry who self-reported the variables .Confirmatory factor analysis was conducted to detect potential Common Method Bias and the results suggested that CMB was not serious as con -cerned.Theoretical hypotheses were tested using polynomial regression .The results suggested that after controlling for affective commitment, there was U-shaped relationship between perceived organizational support and work engagement , such that only over a certain point perceived organizational support was positively related with work engagement .Moreover , the non-linear relation-ship was moderated by affective commitment .Specifically , for those with high affective commitment , perceived organizational support was related to work engagement in a U-shaped manner , whereas the relationship was linear among those with low affective commitment. Our research shed light on the negative effect of perceived organizational support on work engagement and
孙健敏; 陆欣欣; 孙嘉卿
2015-01-01
As a type of important job resource , perceived organizational support has been identified as a salient antecedent of work engagement .However , the extant literature has ignored that with the norm of reciprocity as its core tenet , perceived organization-al support requires reciprocation from the recipients .Then, below a certain point, employees who perceive organizational support are expected to reciprocate by performing extra-role behavior , which reduces their engagement in assigned work .Based on Job-Demand Resource model and social exchange theory , we argue that there may be U-shaped relationship between perceived organi-zational support and work engagement .Moreover, the extent to which individuals are engaged in extra-role performance is pro-foundly shaped by their affective commitment with the organization .Therefore, we propose that affective commitment moderates the curvilinear relationship between perceived organizational support and work engagement . We collected data among 302 employees with diverse positions in securities industry who self-reported the variables .Confirmatory factor analysis was conducted to detect potential Common Method Bias and the results suggested that CMB was not serious as con -cerned.Theoretical hypotheses were tested using polynomial regression .The results suggested that after controlling for affective commitment, there was U-shaped relationship between perceived organizational support and work engagement , such that only over a certain point perceived organizational support was positively related with work engagement .Moreover , the non-linear relation-ship was moderated by affective commitment .Specifically , for those with high affective commitment , perceived organizational support was related to work engagement in a U-shaped manner , whereas the relationship was linear among those with low affective commitment. Our research shed light on the negative effect of perceived organizational support on work engagement and
Motion of Plasmoid in a Curvilinear Magnetic Field
The passage of. a plasmoid through the magnetic field of a toroidal solenoid and its decontamination from heavy ion impurities have been studied theoretically and experimentally. The theoretical analysis has been carried out within the framework of a drift approximation. The passage of the plasma is achieved through the closing currents which SinelnikoV assumed to exist. The circuit-closing currents substantially reduce the polarization fields but, as calculations show, do not prevent me drift ofheavy ions to the chamber walls. Even in dense plasma, in which 4πn0Mc2/H20 >> 1, the heavy-ion drift is governed by the same laws as in the single-particle approximation. More precise analysis of the field structure shows that, in addition to the polarization field perpendicular to the torus plane, there is a radial electric field directed towards the inner wall of the toroidal chamber. The magnitude of the polarization field is determined essentially by the shorting currents and measurement of the polarization fields therefore confirms indirectly the assumed existence of these currents. Earlier experiments showed that the measured polarization fields agree in order of magnitude with the theoretical predictions. We study the results of the experimental investigation of the passage and decontamination of fast plasmoids of high density (n0 > 1013 cm-3, 4πn0Mc2/H20 ≃ 5 x 103 >> 1). A coaxial source with a pulsed gas inlet was used to obtain the plasmoids (1 cm3 of hydrogen at atmospheric pressure). The 17-μF source bank was charged to 18 kV. After passing through the rectilinear section of the magnetic field (L = 150 cm) the plasma entered the toroidal magnetic field (radius of curvature, 75 cm; angle of deflection, approximately 90°). The magnitude of the pulsed magnetic field reached 10 kOe and remained virtually unchanged during the passage of the plasma (T = 10 ms). A Thompson mass-spectrograph, a transit mass-analyser, electric and high-frequency probes, calorimeters and a plasmascope were employed in the utilization of the plasmoids. On entry into the toroidal solenoid, the velocity of the plasma fronts of density n1 ∼ 1012 cm-3 and n2 ∼ 1013 cm-3 was 7 x 107 cm/s. By photometric measurement of the Thompson parabolas, the mean energy of the H+ ions was found to exceed 3 keV while impurities accounted for about 40%. The main impurities were carbon and oxygen ions and the ions of the electrode materials, and their mean energy was higher than that of the hydrogen ions. As the plasmoid moved along the toroidal solenoid, the energy transferred by the plasma and the total number of charged particles decreased by factors of 5 and 3, respectively, for H = 8000 be; at the same time the fraction of fast particles in the H+ ion spectrum declined and the mean energy fell to 2 or 2.5 keV. The velocity of the density front ni remained unchanged, while that of the density front ne fell to approximately 4 x 107 cm/s. The impurities in the fast plasmoid (mainly C++ and O++ ions) accounted for about 5%. The mean energy of the impurity ions passing through the toroidal field was approximately half the initial energy (after passing through the straight solenoid). (author)
Misperceptions in the trajectories of objects undergoing curvilinear motion.
Yilmaz, Ozgur; Tripathy, Srimant P; Ogmen, Haluk
2012-01-01
Trajectory perception is crucial in scene understanding and action. A variety of trajectory misperceptions have been reported in the literature. In this study, we quantify earlier observations that reported distortions in the perceived shape of bilinear trajectories and in the perceived positions of their deviation. Our results show that bilinear trajectories with deviation angles smaller than 90 deg are perceived smoothed while those with deviation angles larger than 90 degrees are perceived sharpened. The sharpening effect is weaker in magnitude than the smoothing effect. We also found a correlation between the distortion of perceived trajectories and the perceived shift of their deviation point. Finally, using a dual-task paradigm, we found that reducing attentional resources allocated to the moving target causes an increase in the perceived shift of the deviation point of the trajectory. We interpret these results in the context of interactions between motion and position systems. PMID:22615775
Misperceptions in the trajectories of objects undergoing curvilinear motion.
Ozgur Yilmaz
Full Text Available Trajectory perception is crucial in scene understanding and action. A variety of trajectory misperceptions have been reported in the literature. In this study, we quantify earlier observations that reported distortions in the perceived shape of bilinear trajectories and in the perceived positions of their deviation. Our results show that bilinear trajectories with deviation angles smaller than 90 deg are perceived smoothed while those with deviation angles larger than 90 degrees are perceived sharpened. The sharpening effect is weaker in magnitude than the smoothing effect. We also found a correlation between the distortion of perceived trajectories and the perceived shift of their deviation point. Finally, using a dual-task paradigm, we found that reducing attentional resources allocated to the moving target causes an increase in the perceived shift of the deviation point of the trajectory. We interpret these results in the context of interactions between motion and position systems.
Parental competence and maltreatment: the curvilinear influence of plan complexity.
Strickland, Amanda L; Samp, Jennifer A
2013-03-01
A parent's ability to plan for child behavior problems was proposed to influence the relationship between parental competence and attitudes/beliefs about parenting behaviors. One hundred and one parents from three community sites completed questionnaires measuring parental competence, plan complexity, and attitudes/beliefs about parenting. Results indicated that plan complexity significantly influenced the relationship between parental competence and judgments about corporal punishment. The same influence existed between parental competence and power independence. We discuss these results with regard to forwarding theoretical work on planning processes, as well as practical implications for enhancing parent education curricula to better address the constructive management of difficult child behaviors. PMID:23027836
Height among Women is Curvilinearly Related to Life History Strategy
Buunk, Abraham P.; Pollet, Thomas V.; Klavina, Liga; Figueredo, Aurelio Jose; Dijkstra, Pieternel
2009-01-01
It was hypothesized that women of medium height would show a more secure, long-term mating pattern characterized by less jealousy, less intrasexual competition and a "slower" life history strategy. In three samples of female undergraduate students clear support was found for these hypotheses. In Stu
Analyzing genotype-by-environment interaction using curvilinear regression
Dulce Gamito Santinhos Pereira
2012-12-01
Full Text Available In the context of multi-environment trials, where a series of experiments is conducted across different environmental conditions, the analysis of the structure of genotype-by-environment interaction is an important topic. This paper presents a generalization of the joint regression analysis for the cases where the response (e.g. yield is not linear across environments and can be written as a second (or higher order polynomial or another non-linear function. After identifying the common form regression function for all genotypes, we propose a selection procedure based on the adaptation of two tests: (i a test for parallelism of regression curves; and (ii a test of coincidence for those regressions. When the hypothesis of parallelism is rejected, subgroups of genotypes where the responses are parallel (or coincident should be identified. The use of the Scheffé multiple comparison method for regression coefficients in second-order polynomials allows to group the genotypes in two types of groups: one with upward-facing concavity (i.e. potential yield growth, and the other with downward-facing concavity (i.e. the yield approaches saturation. Theoretical results for genotype comparison and genotype selection are illustrated with an example of yield from a non-orthogonal series of experiments with winter rye (Secalecereale L.. We have deleted 10 % of that data at random to show that our meteorology is fully applicable to incomplete data sets, often observed in multi-environment trials.
Owman, H; Ericsson, Y B; Englund, M; Tiderius, C J; Tjörnstrand, J; Roos, Ewa M.; Dahlberg, L E
2014-01-01
OBJECTIVE: To examine the association between the relaxation time (T1Gd) of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and grade of tibiofemoral joint space narrowing (JSN) and osteophytosis 11 years later, in a cohort of meniscectomized patients. DESIGN: Patients...
Transformational leadership and R&D innovation : taking a curvilinear approach
Eisenbeiss, Silke Astrid; Boerner, Sabine
2010-01-01
Only few studies have examined innovation at the team level so far. Moreover, there are different positions when it comes to the role of leadership in engendering R&D team innovation. Innovation research outlines that high levels of team autonomy are beneficial to innovation in R&D teams and thus suggests that leaders should give as little intellectual guidance as possible. Leadership research proposes transformational leadership as a lever for facilitating team innovation. We integrate these...
CellFIT: a cellular force-inference toolkit using curvilinear cell boundaries.
G Wayne Brodland
Full Text Available Mechanical forces play a key role in a wide range of biological processes, from embryogenesis to cancer metastasis, and there is considerable interest in the intuitive question, "Can cellular forces be inferred from cell shapes?" Although several groups have posited affirmative answers to this stimulating question, nagging issues remained regarding equation structure, solution uniqueness and noise sensitivity. Here we show that the mechanical and mathematical factors behind these issues can be resolved by using curved cell edges rather than straight ones. We present a new package of force-inference equations and assessment tools and denote this new package CellFIT, the Cellular Force Inference Toolkit. In this approach, cells in an image are segmented and equilibrium equations are constructed for each triple junction based solely on edge tensions and the limiting angles at which edges approach each junction. The resulting system of tension equations is generally overdetermined. As a result, solutions can be obtained even when a modest number of edges need to be removed from the analysis due to short length, poor definition, image clarity or other factors. Solving these equations yields a set of relative edge tensions whose scaling must be determined from data external to the image. In cases where intracellular pressures are also of interest, Laplace equations are constructed to relate the edge tensions, curvatures and cellular pressure differences. That system is also generally overdetermined and its solution yields a set of pressures whose offset requires reference to the surrounding medium, an open wound, or information external to the image. We show that condition numbers, residual analyses and standard errors can provide confidence information about the inferred forces and pressures. Application of CellFIT to several live and fixed biological tissues reveals considerable force variability within a cell population, significant differences between populations and elevated tensions along heterotypic boundaries.
In this paper, we improve the collocation method for computing vibrational spectra that was presented in Avila and Carrington, Jr. [J. Chem. Phys. 139, 134114 (2013)]. Using an iterative eigensolver, energy levels and wavefunctions are determined from values of the potential on a Smolyak grid. The kinetic energy matrix-vector product is evaluated by transforming a vector labelled with (nondirect product) grid indices to a vector labelled by (nondirect product) basis indices. Both the transformation and application of the kinetic energy operator (KEO) scale favorably. Collocation facilitates dealing with complicated KEOs because it obviates the need to calculate integrals of coordinate dependent coefficients of differential operators. The ideas are tested by computing energy levels of HONO using a KEO in bond coordinates
Biological arches and changes to the curvilinear form of the aging maxilla.
Zadoo, V P; Pessa, J E
2000-08-01
The facial skeleton can be conceptualized as a series of arches aligned along a vertical axis, with regional differences in shape. Previous work suggested that the maxilla undergoes differential growth with time. Because these arch forms resemble geometric forms, it may be possible to measure changes to their shape with the aging process. A contour analysis of the aging maxilla was undertaken. Computed tomographic data were assembled retrospectively. Only men were studied, and they were divided into two groups: young (aged 18 to 24 years; n = 6) and old (aged 40 to 66 years; n = 6). The computed tomography data were reconstructed into three-dimensional images and underwent standardization for comparison purposes. An axial view of the maxilla along the Frankfort horizontal was used for analysis. To quantify changes between curves, measurements were made of the vertical distance from eight equidistant points along each curve perimeter to a standardized baseline. Average arch forms for young and old men were then generated for comparison purposes. Each of the eight points along the older maxillary arch form existed further from the baseline than the younger arch form. This difference reached statistical significance at three of the eight points measured along the two curves. The greatest difference occurred at point 8 (p = .0006), which was at the medial maxilla near the nasomaxillary junction. The results of the study suggest that the actual contour of the maxilla undergoes changes as a result of the aging process. Mathematically defined idealized skeletal contours could help guide reconstructive surgery and aesthetic augmentation of the facial skeleton in the future. In addition, certain soft tissues of the face and torso seem to share a common shape (an alpha contour). This shape may also exhibit idealized forms open to quantitative analysis. The skeletal arch form and alpha contour most likely exhibit sexual dimorphism and will require further investigation. The ubiquity of the arch form in nature and possible implications for growth and development of the human facial skeleton are also discussed. PMID:10946946
Avila, Gustavo, E-mail: Gustavo-Avila@telefonica.net; Carrington, Tucker, E-mail: Tucker.Carrington@queensu.ca [Chemistry Department, Queen’s University, Kingston, Ontario K7L 3N6 (Canada)
2015-12-07
In this paper, we improve the collocation method for computing vibrational spectra that was presented in Avila and Carrington, Jr. [J. Chem. Phys. 139, 134114 (2013)]. Using an iterative eigensolver, energy levels and wavefunctions are determined from values of the potential on a Smolyak grid. The kinetic energy matrix-vector product is evaluated by transforming a vector labelled with (nondirect product) grid indices to a vector labelled by (nondirect product) basis indices. Both the transformation and application of the kinetic energy operator (KEO) scale favorably. Collocation facilitates dealing with complicated KEOs because it obviates the need to calculate integrals of coordinate dependent coefficients of differential operators. The ideas are tested by computing energy levels of HONO using a KEO in bond coordinates.
Marital Adjustment Over the Family Life Cycle: The Issue of Curvilinearity
Spanier, Graham B.; And Others
1975-01-01
Marital adjustment over the family life cycle is reexamined using data from probability samples of married couples studied in coordinated research projects in three different states--Iowa, Ohio, and Georgia. (Author)
CellFIT: A Cellular Force-Inference Toolkit Using Curvilinear Cell Boundaries
Brodland, G. Wayne; Veldhuis, Jim H.; Kim, Steven; Perrone, Matthew; Mashburn, David; Hutson, M. Shane
2014-01-01
Mechanical forces play a key role in a wide range of biological processes, from embryogenesis to cancer metastasis, and there is considerable interest in the intuitive question, “Can cellular forces be inferred from cell shapes?” Although several groups have posited affirmative answers to this stimulating question, nagging issues remained regarding equation structure, solution uniqueness and noise sensitivity. Here we show that the mechanical and mathematical factors behind these issues can b...
APPLIED PROBLEMS OF CURVILINEAR MOTION DYNAMICS OF ALL-WHEEL DRIVE TRACTION MEANS
G. S. Gorin
2014-01-01
Full Text Available Fundamental principles for hybrid theory on turning of an all-wheel drive system are given in the paper. The paper shows expediency of accounting longitudinal additional tangential reactions (parasitic forces in contacts of central and lateral wheels with foundation. Algorithms for calculating additional tangential reactions have been proposed in the paper. The paper presents calculation kinematics model for turning of steered and rigid bogie with inter-wheel differential at various axial drive.
Marital Adjustment Over the Family Life Cycle: The Issue of Curvilinearity.
Spanier, Graham B.; And Others
Marital adjustment over the family life cycle is reexamined using data from probability samples of married couples studied in coordinated research projects in three different states--Iowa, Ohio, and Georgia. A total of 1,584 respondents completed the Locke-Wallace Marital Adjustment Scale and responded to questions about stage of the family life…
Curvilinear relationship between phonological working memory load and social-emotional modulation.
Mano, Quintino R; Brown, Gregory G; Bolden, Khalima; Aupperle, Robin; Sullivan, Sarah; Paulus, Martin P; Stein, Murray B
2013-01-01
Accumulating evidence suggests that working memory load is an important factor for the interplay between cognitive and facial-affective processing. However, it is unclear how distraction caused by perception of faces interacts with load-related performance. We developed a modified version of the delayed match-to-sample task wherein task-irrelevant facial distracters were presented early in the rehearsal of pseudoword memoranda that varied incrementally in load size (1-syllable, 2-syllables, or 3-syllables). Facial distracters displayed happy, sad, or neutral expressions in Experiment 1 (N=60) and happy, fearful, or neutral expressions in Experiment 2 (N=29). Facial distracters significantly disrupted task performance in the intermediate load condition (2-syllable) but not in the low or high load conditions (1- and 3-syllables, respectively), an interaction replicated and generalised in Experiment 2. All facial distracters disrupted working memory in the intermediate load condition irrespective of valence, suggesting a primary and general effect of distraction caused by faces. However, sad and fearful faces tended to be less disruptive than happy faces, suggesting a secondary and specific valence effect. Working memory appears to be most vulnerable to social-emotional information at intermediate loads. At low loads, spare capacity is capable of accommodating the combinatorial load (1-syllable plus facial distracter), whereas high loads maximised capacity and deprived facial stimuli from occupying working memory slots to cause disruption. PMID:22928750
Curvilinear relationship between phonological working memory load and social-emotional modulation
Quintino R. Mano; Brown, Gregory G.; Bolden, Khalima; Aupperle, Robin; Sullivan, Sarah; Paulus, Martin P.; Stein, Murray B.
2012-01-01
Accumulating evidence suggests that working memory load is an important factor for the interplay between cognitive and facial-affective processing. However, it is unclear how distraction caused by perception of faces interacts with load-related performance. We developed a modified version of the delayed match-to-sample task wherein task-irrelevant facial distracters were presented early in the rehearsal of pseudoword memoranda that varied incrementally in load size (1-syllable, 2-syllables, o...
Curvilinear Three-Dimensional Modeling of Spinal Curves with Dual Kriging.
Poncet, PHILIPPE; Trochu, FRANÇOIS; Dansereau, JEAN
1999-01-01
In spinal deformation studies, three-dimensional reconstruction of the spine is frequently represented as a curve in space fitted to the vertebral centroids. Conventional interpolation techniques such as splines, Bezier and the least squares method are limited since they cannot describe precisely the great variety of spinal morphologies. This article presents a more general technique called dual kriging, which includes two mathematical constituents (drift and covariance) to adjust the interpolated functions to spinal deformity better. The cross-validation technique was used to compare the parametric representations of spinal curves with different combinations of drift and covariance functions. Model validation was performed from a series of analytic curves reflecting typical scoliotic spines. Calculation of geometric torsion, a sensitive parameter, was done to evaluate the accuracy of the kriging models. The best model showed an absolute mean difference of 1.2 x 10(-5) (+/- 7.1 x 10(-5) ) mm(-1) between the analytical and estimated geometric torsions compared to 5.25 x 10(-3) (+/- 3.7 x 10(-2) ) mm(-1) for the commonly used least-squares Fourier series method, a significant improvement in spinal torsion evaluation. PMID:11264834
A Hybrid PO - Higher-Order Hierarchical MoM Formulation using Curvilinear Geometry Modeling
Jørgensen, E; Meincke, Peter; Breinbjerg, Olav
2003-01-01
A very efficient hybrid PO-MoM method has been presented. In contrast to existing methods, the present solution employs higher-order hierarchical basis functions to discretize the MoM and PO currents. This allows to reduce the number of basis functions in both the PO and MoM regions considerably which implies a very modest memory requirement. Nevertheless, the hierarchical feature of the basis functions maintains the ability to treat small geometrical details efficiently. In addition, the sca...
A Hybrid PO - Higher-Order Hierarchical MoM Formulation using Curvilinear Geometry Modeling
Jørgensen, E.; Meincke, Peter; Breinbjerg, Olav
2003-01-01
A very efficient hybrid PO-MoM method has been presented. In contrast to existing methods, the present solution employs higher-order hierarchical basis functions to discretize the MoM and PO currents. This allows to reduce the number of basis functions in both the PO and MoM regions considerably...
Modelling the Shallow Water Equations in Curvilinear Coordinates with Physical Application
Wingenter, S
2005-01-12
The goal of this project is to provide the capability for simulating fluid flow on complicated geometries, such as in the Bahia de Todos Santos. The Bahia de Todos Santos is a bay situated in the northwest corner of Mexico, off the coast of Ensenada and south of San Diego, California, USA. Figure 1.1 shows the Bahia de Todos Santos. It is part of an image taken from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Aqua and Terra satellites in late June and early July 2003 [8]. Roughly 200 square kilometers in size, the bay also contains two islands off the peninsula of Punta Banda. Characteristics of flow in this bay are driven by the moon tide (M2) and wind forcing [9].
Autofocus algorithm for synthetic aperture radar imaging with large curvilinear apertures
An approach to autofocusing for large curved synthetic aperture radar (SAR) apertures is presented. Its essential feature is that phase corrections are being extracted not directly from SAR images, but rather from reconstructed SAR phase-history data representing windowed patches of the scene, of sizes sufficiently small to allow the linearization of the forward- and back-projection formulae. The algorithm processes data associated with each patch independently and in two steps. The first step employs a phase-gradient-type method in which phase correction compensating (possibly rapid) trajectory perturbations are estimated from the reconstructed phase history for the dominant scattering point on the patch. The second step uses phase-gradient-corrected data and extracts the absolute phase value, removing in this way phase ambiguities and reducing possible imperfections of the first stage, and providing the distances between the sensor and the scattering point with accuracy comparable to the wavelength. The features of the proposed autofocusing method are illustrated in its applications to intentionally corrupted small-scene 2006 Gotcha data. The examples include the extraction of absolute phases (ranges) for selected prominent point targets. They are then used to focus the scene and determine relative target–target distances. (paper)
Karavelas, Menelaos I
2008-01-01
In this paper we consider the problem of monitoring an art gallery modeled as a polygon, the edges of which are arcs of curves, with edge or mobile guards. Our focus is on piecewise-convex polygons, i.e., polygons that are locally convex, except possibly at the vertices, and their edges are convex arcs. We transform the problem of monitoring a piecewise-convex polygon to the problem of 2-dominating a properly defined triangulation graph with edges or diagonals, where 2-dominance requires that every triangle in the triangulation graph has at least two of its vertices in its 2-dominating set. We show that: (1) $\\lfloor\\frac{n+1}{3}\\rfloor$ diagonal guards are always sufficient and sometimes necessary, and (2) $\\lfloor\\frac{2n+1}{5}\\rfloor$ edge guards are always sufficient and $\\lfloor\\frac{2n}{5}\\rfloor$ edge guards are sometimes necessary, in order to 2-dominate a triangulation graph. Based on the above-mentioned results, we prove that, for piecewise-convex polygons, we can compute: (1) a mobile guard set of ...
Qin, Xin; Direnzo, Marco S.; Xu, Minya; Duan, Yilong
2014-01-01
Two studies were conducted to address the potential nonlinear relationship between emotional exhaustion and voice. Study 1 developed and tested a model rooted in conservation of resources theory in which responses to emotional exhaustion are determined by individual-level and group-level conditions that influence the perceived safety and efficacy of voice and drive prohibitive voice behaviors by giving rise to either resource-conservation-based or resource-acquisition-based motiva...
Janssen, O
2001-01-01
Activation theory suggests that intermediate rather than low or high levels of quantitative job demands benefit job performance and job satisfaction among managers. Using an equity theory framework, I hypothesize that perceptions of effort-reward fairness moderate these inverted U-shaped demand-resp
AbuAlSaud, Moataz
2012-07-01
The purpose of this thesis is to solve unsteady two-dimensional compressible Navier-Stokes equations for a moving mesh using implicit explicit (IMEX) Runge- Kutta scheme. The moving mesh is implemented in the equations using Arbitrary Lagrangian Eulerian (ALE) formulation. The inviscid part of the equation is explicitly solved using second-order Godunov method, whereas the viscous part is calculated implicitly. We simulate subsonic compressible flow over static NACA-0012 airfoil at different angle of attacks. Finally, the moving mesh is examined via oscillating the airfoil between angle of attack = 0 and = 20 harmonically. It is observed that the numerical solution matches the experimental and numerical results in the literature to within 20%.
Van Ruysseveldt, Joris; Van Dijke, Marius
2011-01-01
textabstractBuilding on theoretical frameworks like the Job Demands Control model and Action Theory we tested whether the relationship between workload and employees’ experiences of opportunities for workplace learning is of an inverted u-shaped nature and whether autonomy moderates this relationship. We predicted that – at moderate levels of autonomy - workload was positively associated with learning opportunities at low levels of workload, but negatively at high levels of workload. Also, we...
van Ruysseveldt, Joris; van Dijke, Marius
2011-01-01
Building on theoretical frameworks like the Job Demands Control model and Action Theory we tested whether the relationship between workload and employees' experiences of opportunities for workplace learning is of an inverted u-shaped nature and whether autonomy moderates this relationship. We predicted that--at moderate levels of…
Kwak, D.
1994-01-01
INS3D computes steady-state solutions to the incompressible Navier-Stokes equations. The INS3D approach utilizes pseudo-compressibility combined with an approximate factorization scheme. This computational fluid dynamics (CFD) code has been verified on problems such as flow through a channel, flow over a backwardfacing step and flow over a circular cylinder. Three dimensional cases include flow over an ogive cylinder, flow through a rectangular duct, wind tunnel inlet flow, cylinder-wall juncture flow and flow through multiple posts mounted between two plates. INS3D uses a pseudo-compressibility approach in which a time derivative of pressure is added to the continuity equation, which together with the momentum equations form a set of four equations with pressure and velocity as the dependent variables. The equations' coordinates are transformed for general three dimensional applications. The equations are advanced in time by the implicit, non-iterative, approximately-factored, finite-difference scheme of Beam and Warming. The numerical stability of the scheme depends on the use of higher-order smoothing terms to damp out higher-frequency oscillations caused by second-order central differencing. The artificial compressibility introduces pressure (sound) waves of finite speed (whereas the speed of sound would be infinite in an incompressible fluid). As the solution converges, these pressure waves die out, causing the derivation of pressure with respect to time to approach zero. Thus, continuity is satisfied for the incompressible fluid in the steady state. Computational efficiency is achieved using a diagonal algorithm. A block tri-diagonal option is also available. When a steady-state solution is reached, the modified continuity equation will satisfy the divergence-free velocity field condition. INS3D is capable of handling several different types of boundaries encountered in numerical simulations, including solid-surface, inflow and outflow, and far-field boundaries. Three machine versions of INS3D are available. INS3D for the CRAY is written in CRAY FORTRAN for execution on a CRAY X-MP under COS, INS3D for the IBM is written in FORTRAN 77 for execution on an IBM 3090 under the VM or MVS operating system, and INS3D for DEC RISC-based systems is written in RISC FORTRAN for execution on a DEC workstation running RISC ULTRIX 3.1 or later. The CRAY version has a central memory requirement of 730279 words. The central memory requirement for the IBM is 150Mb. The memory requirement for the DEC RISC ULTRIX version is 3Mb of main memory. INS3D was developed in 1987. The port to the IBM was done in 1990. The port to the DECstation 3100 was done in 1991. CRAY is a registered trademark of Cray Research Inc. IBM is a registered trademark of International Business Machines. DEC, DECstation, and ULTRIX are trademarks of the Digital Equipment Corporation.
R Muralidhar
2012-01-01
Full Text Available Context : Pediatric cataract surgery is traditionally done with the aid of high-molecular-weight viscoelastics which are expensive. It needs to be determined if low-cost substitutes are just as successful. Aims : The study aims to determine the success rates for anterior and posterior capsulorrhexis and intraocular lens (IOL implantation in the bag for pediatric cataract surgery performed with the aid of a low-molecular-weight viscoelastic. Settings and Design : Nonrandomized observational study. Materials and Methods: Children less than 6 years of age who underwent cataract surgery with IOL implantation in the period May 2008-May 2009 were included. The surgeries were done by pediatric ophthalmology fellows. A standard procedure of anterior capsulorrhexis, lens aspiration with primary posterior capsulorrhexis, anterior vitrectomy, and IOL implantation was followed. Three parameters were studied: successful completion of anterior and posterior capsulorrhexis and IOL implantation in the bag. Results: 33 eyes of 28 children were studied. The success rate for completion was 66.7% and 88.2 % for anterior and posterior capsulorrhexis, respectively. IOL implantation in the bag was successful in 87.9%. Conclusions: 2% hydroxypropylmethylcellulose is a viable low-cost alternative to more expensive options similar to high-molecular-weight viscoelastics. This is of great relevance to hospitals in developing countries.
Borazjani, Iman; Asgharzadeh, Hafez
2015-11-01
Flow simulations involving complex geometries and moving boundaries suffer from time-step size restriction and low convergence rates with explicit and semi-implicit schemes. Implicit schemes can be used to overcome these restrictions. However, implementing implicit solver for nonlinear equations including Navier-Stokes is not straightforward. Newton-Krylov subspace methods (NKMs) are one of the most advanced iterative methods to solve non-linear equations such as implicit descritization of the Navier-Stokes equation. The efficiency of NKMs massively depends on the Jacobian formation method, e.g., automatic differentiation is very expensive, and matrix-free methods slow down as the mesh is refined. Analytical Jacobian is inexpensive method, but derivation of analytical Jacobian for Navier-Stokes equation on staggered grid is challenging. The NKM with a novel analytical Jacobian was developed and validated against Taylor-Green vortex and pulsatile flow in a 90 degree bend. The developed method successfully handled the complex geometries such as an intracranial aneurysm with multiple overset grids, and immersed boundaries. It is shown that the NKM with an analytical Jacobian is 3 to 25 times faster than the fixed-point implicit Runge-Kutta method, and more than 100 times faster than automatic differentiation depending on the grid (size) and the flow problem. The developed methods are fully parallelized with parallel efficiency of 80-90% on the problems tested.
Wendland, David; Aranda Alonso, María; Kobe, Alexander
2015-01-01
The current state of research on the design and construction of late Gothic vaults is principally based on the interpretation of sources, but rarely on surveys of existing vaults. In particular the idea for the criteria upon which the radii of the single ribs and arches were determined (so-called "principal arch"), is found to derive from sources dating from later periods when Gothic vaulting was no longer generally practised. In fact, this interpretation cannot be supported by geometric surv...
Total Knee Replacement for Women
Full Text Available ... It’s important to maintain this as a contiguous soft tissue flap, which will be important for closure. When ... osteophytes out. You have less tethering of the soft tissue over those osteophytes. Ken, how often do you ...
Baxi Vaibhavi
2010-01-01
Full Text Available This is a report of anterior osteophytes on the cervical vertebra resulting in distortion of the airway and leading to difficulty during intubation. The osteophytes associated with the syndrome of diffuse idiopathic skeletal hyperostosis were at the C2-3 and C6-7, T1 level and resulted in anterior displacement of the pharynx and the trachea respectively.
Spinal surgery -- cervical - series (image)
... on the vertebral bodies (osteophytes), which compress spinal nerves, trauma, and narrowing (stenosis) of the spinal column around the spinal cord. Symptoms of cervical spine problems include: pain that interferes with daily ...
Total Knee Replacement for Women
Full Text Available ... over those osteophytes. Ken, how often do you use this approach, and what patients would not be a good candidate for this approach? I use this approach at about 80 percent of my ...
Anterior Approach Total Hip Replacement
Full Text Available ... mild dysplasia with cystic changes and loss of joint space. No real significant osteophytes we’re going ... inclination to her hips and her slightly dysplastic joint; otherwise having excellent and relatively normal anatomy. Any ...
Anterior Approach Total Hip Replacement
Full Text Available ... dysplasia with cystic changes and loss of joint space. No real significant osteophytes we’re going to ... sort of used to looking at things in space. I agree completely. But when you put your ...
Anatomic Total Shoulder System
Full Text Available ... patient is a 78-year-old male who has osteoarthritis of his left shoulder. If you look ... does not have a really big inferior osteophyte. Has a little bit of proximal migration and even ...
Full Text Available ... out the plexus or the nerves, there are large osteophytes that might get in the way, or ... And since we couldn’t quite fit the large -- the second reamer, in here, we're just ...
Total Knee Replacement for Women
Full Text Available ... point, because they actually aid in the initial exposure if you take the osteophytes out. You have ... what do you do for post-op pain management? Patients are under a spinal anesthetic and most ...
Anatomic Total Shoulder System
Full Text Available ... severe osteoarthritis. He does not have a really big inferior osteophyte. Has a little bit of proximal ... that you can do to give yourself a big break as far as glenoid exposure is concerned ...
Intra- and interobserver agreement of computed tomography in assessment of the mandibular condyle
Cho, Bong Hae; Jung, Yun Hoa [Pusan National Univ. College of Dentistry, Pusan (Korea, Republic of)
2007-12-15
To study the intra- and interobserver agreement of multidetector row computed tomography (MDCT) in interpretation of degenerative changes of the mandibular condyle. Five observers independently evaluated one hundred temporomandibular joint MDCT images for signs of osteophytes, erosion, sclerosis and flattening. The intra- and interobserve agreements were calculated by using Kappa statistics. The intraobserver agreement was substantial for erosion (k=0.75), flattening (k=0.74) and sclerosis (k=0.72) and almost perfect for osteophytes (k=0.84). The interobserver agreement was fair for flattening (k=0.39), moderate for erosion (k=0.58) and sclerosis (k=0.48) and substantial for osteophytes (k=0.75). This study shows that we can expert good agreement for the presence of osteophytes, but not for flattening in the interpretation of MDCT images of the condyle.
Full Text Available ... going to come under the acromium so that leave the coracoacromial ligament to reinforce that deltoid flap ... want to be very sure you didn’t leave on any osteophytes inferiorally on the glenoid that ...
Full Text Available ... going to use these cutaway reamers with square teeth that Zimmer provides for these minimally invasive procedures. ... we spin forward and actually catch the reamer teeth on instruments or on osteophytes, we can have ...
Anatomic Total Shoulder System
Full Text Available ... inferior osteophyte. Has a little bit of proximal migration and even has a little bit of juxta- ... push gradually medially. It's sort of like the concept of when you're reaming a femur, don' ...
Full Text Available ... is a very nice time that we can access those osteophytes that we tend to get about ... extend an AD duct, helps us gain good access to the working on the proximal femur. The ...
Total Knee Replacement for Women
Full Text Available ... m removing some lateral osteophytes, which, again, will help me getting my patella subluxated laterally. Now I ... with computer navigation. I believe that that does help with the overall alignment of the knee. We’ ...
Total Knee Replacement for Women
Full Text Available ... see that the medial wear pattern present, as well as some posterior osteophytes on the femur that ... our plan is to resurface the patella as well. So if you can go ahead and we’ ...
Risk Factors for the Development of Adjacent Segment Disease Following Anterior Cervical Arthrodesis
Ezgi Akar; Mehmet Ufuk Akmil; Merih İş
2015-01-01
Aim: The aim of this study was to clinically and radiologically evaluate the efficacy of anterior cervical discectomy and fusion (ACDF) in the treatment of adjacent level degeneration. Methods: We retrospectively evaluated 89 patients (55 females, 34 males) who underwent ACDF. Adjacent segment degeneration findings were evaluated by investigating new osteophyte formation, growth of existing osteophytes, ossification of the anterior longitudinal ligament, presence of inter...
Reliability and validity of ultrasound imaging of features of knee osteoarthritis in the community
Pearce Mark S
2011-04-01
Full Text Available Abstract Background Radiographs are the main outcome measure in epidemiological studies of osteoarthritis (OA. Ultrasound imaging has unique advantages in that it involves no ionising radiation, is easy to use and visualises soft tissue structures. Our objective was to measure the inter-rater reliability and validity of ultrasound imaging in the detection of features of knee OA. Methods Eighteen participants from a community cohort, had both knees scanned by two trained musculoskeletal sonographers, up to six weeks apart. Inter-rater reliability for osteophytes, effusion size and cartilage thickness was calculated by estimating Kappa (κ and Intraclass correlation coefficients (ICC, as appropriate. A measure of construct validity was determined by estimating κ between the two imaging modalities in the detection of osteophytes. Results Reliability: κ for osteophyte presence was 0.77(right femur, 0.65(left femur and 0.88 for both tibia. ICCs for effusion size were 0.70(right and 0.85(left. Moderate to substantial agreement was found in cartilage thickness measurements. Validity: For osteophytes, κ was moderate to excellent at 0.52(right and 0.75(left. Conclusion Substantial to excellent agreement was found between ultrasound observers for the presence of osteophytes and measurement of effusion size; it was moderate to substantial for femoral cartilage thickness. Moderate to substantial agreement was observed between ultrasound and radiographs for osteophyte presence.
Drevets, Wayne C.; Price, Joseph L.; Furey, Maura L.
2008-01-01
The neural networks that putatively modulate aspects of normal emotional behavior have been implicated in the pathophysiology of mood disorders by converging evidence from neuroimaging, neuropathological and lesion analysis studies. These networks involve the medial prefrontal cortex (MPFC) and closely related areas in the medial and caudolateral orbital cortex (medial prefrontal network), amygdala, hippocampus, and ventromedial parts of the basal ganglia, where alterations in grey matter vol...
De Lasalle, Julie; Alexander, Kate; Olive, Julien; Laverty, Sheila
2016-09-01
A better understanding of imaging characteristics of equine stifle osteoarthritis (OA) may allow earlier detection and improve prognosis. Objectives of this ex vivo, prospective, methods comparison study were to (1) describe the location and severity of naturally acquired OA lesions in the equine stifle using ultrasound (US), radiography (XR), computed tomography (CT), and macroscopic evaluation (ME); (2) compare the diagnostic performance of each imaging modality with ME; and (3) describe subchondral bone mineral density (BMD) in equine stifle joints with OA using CT. Radiographic, CT, and US evaluations were performed on 23 equine cadaver stifles and compared with ME. Significant associations were found between osteophyte global scores for all imaging modalities (CT, P ˂ 0.0001; XR, P = 0.005; US, P = 0.04) vs. ME osteophyte global scores. Osteophytes were detected most frequently in the medial femorotibial (MFT) joint. A specific pattern of osteophytes was observed, with a long ridge of new bone at the insertion of the MFT joint capsule cranially on the medial femoral condyle. A novel caudo-10°proximo-5°lateral-cranio-disto-medial oblique radiographic projection was helpful for detection of intercondylar osteophytes. Multiplanar CT reformatted images were helpful for characterizing all osteophytes. Osteophyte grades at most sites did not differ among modalities. Low sensitivity/specificity for subchondral bone sclerosis and flattening of femoral condyles suggested that these signs may not be reliable radiographic and CT indicators of equine stifle OA. Equine stifle OA was associated with a decrease in BMD and specific sites of focal subchondral bone resorption/cyst formation were found in some specimens. PMID:27237699
Technetium 99m methylene diphosphonate bone scanning in osteoarthritic hands
In this prospective study, the radiological features characteristic of osteoarthritis of the hand were compared with the radionuclide bone scan images. A total of 32 patients was assessed at 6-monthly intervals for 18 months. Microfocal radiographs were taken at each visit. The high magnification and resolution of this technique permitted direct measurement of joint space width, subchondral sclerosis, osteophyte number and area and juxta-articular radiolucency area for each joint in the hand. Four-hour technetium 99m methylene diphosphonate bone scans were taken at 0 and 12 months and the activity of tracer uptake at each joint scored. The latter was compared with each X-radiographic feature at every visit and the changes between visits analysed. The scan scores did not correlate with any of the X-radiographic features other than osteophyte size. During the study the size of growing and remodelling osteophytes increased significantly at joints with raised or increased isotope uptake. (orig.)
To evaluate the diagnostic performance of radiography for the detection of MRI-detected osteoarthritis-associated features in various articular subregions of the hip joint. Forty-four patients with chronic hip pain (mean age, 63.3 ± 9.5 years), who were part of the Hip Osteoarthritis MRI Scoring (HOAMS) cohort, underwent both weight-bearing anteroposterior pelvic radiography and 1.5 T MRI. The HOAMS study was a prospective observational study involving 52 subjects, conducted to develop a semiquantitative MRI scoring system for hip osteoarthritis features. In the present study, eight subjects were excluded because of a lack of radiographic assessment. On radiography, the presence of superior and medial joint space narrowing, superior and inferior acetabular/femoral osteophytes, acetabular subchondral cysts, and bone attrition of femoral head was noted. On MRI, cartilage, osteophytes, subchondral cysts, and bone attrition were evaluated in the corresponding locations. Diagnostic performance of radiography was compared with that of MRI, and the area under curve (AUC) was calculated for each pathological feature. Compared with MRI, radiography provided high specificity (0.76-0.90) but variable sensitivity (0.44-0.78) for diffuse cartilage damage (using JSN as an indirect marker), femoral osteophytes, acetabular subchondral cysts and bone attrition of the femoral head, and a low specificity (0.42 and 0.58) for acetabular osteophytes. The AUC of radiography for detecting overall diffuse cartilage damage, marginal osteophytes, subchondral cysts and bone attrition was 0.76, 0.78, 0.67, and 0.82, respectively. Diagnostic performance of radiography is good for bone attrition, fair for marginal osteophytes and cartilage damage, but poor for subchondral cysts. (orig.)
Munetaka Iwata
Full Text Available Obesity and high body mass index are associated with a higher incidence of osteoarthritis (OA. The aim of this study is to investigate the involvement of the infrapatellar fat pad (IPFP in the sub-acute effect of a high fat diet (HFD on the development of knee-OA. C57BL/6J male mice were fed either a HFD or a normal diet beginning at seven weeks of age. Tissue sections were evaluated with immunohistological analysis. The IPFP was excised, and mRNA expression profiles were compared using real-time RT-PCR analysis. Osteoarthritic changes were initiated in the HFD group after eight weeks of the HFD. Increased synovial cell number and angiogenesis at the anterior edge of the tibial plateau were exhibited prior to osteophyte formation. Quantitative histological analysis indicated that osteophyte volume was significantly increased in the HFD group after eight weeks, along with an increase in the IPFP volume, the size of individual adipocytes and the number of vessels in the IPFP. Histomorphometrical analysis revealed osteophyte area was significantly associated with IPFP area, individual adipocyte area and vascular area. Real-time RT-PCR analysis demonstrated elevated mRNA expression of inflammatory cytokines, growth factor, and adipokines in the IPFP after eight weeks of the HFD. These findings are in parallel with increased expression of the CD68 macrophage marker after eight weeks of the HFD. Expression levels of the adipokines were significantly correlated with expression of TNF-α, VEGF and TGF-β. Immunohistological analysis revealed that the Nampt protein was highly expressed in the IPFP especially around the site of osteophyte formation. Apoptosis and proliferation of chondrocytes were both enhanced at the site of osteophyte formation, indicating higher cell turnover at this region. These observations suggest the IPFP plays a pivotal role in the formation of osteophytes and functions as a secretory organ in response to a HFD.
Dynamic equations for curved submerged floating tunnel
无
2007-01-01
In virtue of reference Cartesian coordinates, geometrical relations of spatial curved structure are presented in orthogonal curvilinear coordinates. Dynamic equations for helical girder are derived by Hamilton principle. These equations indicate that four generalized displacements are coupled with each other. When spatial structure degenerates into planar curvilinear structure, two generalized displacements in two perpendicular planes are coupled with each other. Dynamic equations for arbitrary curvilinear structure may be obtained by the method used in this paper.
Dynamic ASE Modeling and Optimization of Aircraft with SpaRibs Project
National Aeronautics and Space Administration — We propose development and demonstration of a dynamic aeroservoelastic modeling and optimization system based on curvilinear internal structural arrangements of...
Debruyn, Katrien; Vandermeulen, Eva; Saunders, Jimmy H; Dobbeleir, André A; Ham, Hamphrey R; Peremans, Kathelijne
2013-08-01
Evaluation of glomerular function is a useful part of the diagnostic approach in animals suspected of having renal disease. Time-interval and background region of interest (bg ROI) selection are determining factors when calculating the glomerular filtration ratio (GFR) based on percentage uptake of (99m)technetium-labelled diethylene triamine penta-acetic acid ((99m)Tc-DTPA). Therefore, three different time intervals (60-120 s, 120-180 s, 60-180 s) and three different bg ROIs (C-shape, caudolateral, cranial + caudal) were investigated. In addition, global GFRs based on percentage dose uptake of (99m)Tc-DTPA for the different time-intervals and bg ROIs were compared with the global GFR based on (51)chromium-ethylene diaminic tetra-acetic acid ((51)Cr-EDTA) plasma clearance in nine healthy European domestic shorthair cats. Paired Student's t-tests and linear regression analysis were used to analyse the data. Different time intervals seemed to cause significant variation (P <0.01) in absolute GFR values, regardless of the choice of bg ROI. Significant differences (P <0.01) between bg ROIs were only observed in the 120-180s time interval between the C-shape and cranial + caudal bg ROI, and between the caudolateral and cranial + caudal bg ROI. The caudolateral bg ROI in the 60-180 s time interval showed the highest correlation coefficient (r = 0.882) between (99m)Tc-DTPA and (51)Cr-EDTA, although a significant difference (P <0.05) was present between both techniques. PMID:23349527
Dysphagia due to anterior cervical osteophytosis: case report
Frederico Miguel Santos Silva Marquez Correia; João Paulo de Sousa Goucha Jorge; Ana Sofia Teixeira Neves; Gabriel Filipe Gonçalves Xavier; Marco Miguel Barroso de Oliveira; José Eduardo Paiva Ferreira
2014-01-01
The objective of this study is to highlight the possibility of dysphagia induced by anterior cervical osteophytes. When not diagnosed early this condition may be responsible for complications such as severe dysphagia and potential lung aspiration, especially in elderly patients. Analysis of a case report of a 72-year old woman who presented cervical pain and progressive dysphagia. Imaging studies have shown anterior ce...
Bone scintigraphy in chronic knee pain: comparison with magnetic resonance imaging
Boegard, T.; Rudling, O.; Dahlstrom, J.; Dirksen, H.; Petersson, I.; Jonsson, K.
1999-01-01
OBJECTIVE—To compare increased bone uptake of 99Tcm-MDP and magnetic resonance (MR) detected subchondral lesions, osteophytes, and cartilage defects in the knee in middle aged people with longstanding knee pain. METHODS—Fifty eight people (aged 41-58 years, mean 50) with chronic knee pain, with or without radiographic knee osteoarthritis, were examined with bone scintigraphy. The pattern and the grade of increased bone uptake was assessed. On the same day, a MR examination on a 1.0 T imager was performed. The presence and the grade of subchondral lesions, osteophytes, and cartilage defects were registered. RESULTS—The κ values describing the correlation between increased bone uptake and MR detected subchondral lesions varied between 0.79 and 0.49, and between increased bone uptake and MR detected osteophytes or cartilage defects the values were <0.54. The κ values describing the correlation between the grade of bone uptake and the grade of the different MR findings was <0.57. CONCLUSIONS—Good agreement was found between increased bone uptake and MR detected subchondral lesion. The agreement between increased bone uptake and osteophytes or cartilage defects was in general poor as well as the agreement between the grade of bone uptake and the grade of the MR findings. Keywords: knee; osteoarthritis; magnetic resonance imaging; bone scintigraphy PMID:10343536
Ultrasound findings of the locked metacarpophalangeal joint
Wessely, Kathryn; Healy, Jeremiah; Lee, Justin [Chelsea and Westminster Hospital, Department of Radiology, London (United Kingdom); Owers, Kate [Chelsea and Westminster Hospital, Department of Trauma and Orthopaedics Hand Unit, London (United Kingdom)
2009-01-15
The radiographs and sonographic findings of two cases of locked metacarpophalangeal joint secondary to tethering of the volar plate are described. The presence of osteophytes and the dynamic ultrasound assessment of the volar plate have provided confirmation of the clinical diagnosis prior to surgery. (orig.)
Minimally Invasive Total Knee Arthroplasty
Full Text Available ... 3/4 inch cured osteotome -- it’s relatively simple business to come back in an remove these osteophytes. ... I don't believe so. So even your small patients, they can still accommodate a 12 millimeter ...
Richard M. Young
2015-12-01
Conclusion: ACDF has been demonstrated to be an effective surgical procedure in treating degenerative spine disease in patients with radiculopathy and/or myelopathy. However, in a population with isolated radiculopathy and radiological imaging confirming an anterolateral disc or osteophyte complex, the MIPKF can provide similar results without the associated risks that accompany an anterior cervical spine fusion.
Jacobsen, Steffen; Sonne-Holm, Stig; Søballe, Kjeld;
2004-01-01
: Formation of cysts, osteophytes and subchondral sclerosis was significantly more frequent in men. Average minimum JSW was narrower in women than in men (p < 0.001). In both sexes, minimum JSW decreased after the fourth decade of life, but progressively more so in women. Women reported hip pain more...
Anterior Approach Total Hip Replacement
Full Text Available ... cystic changes and loss of joint space. No real significant osteophytes we’re going to have to ... outliers the big blood-loss case and the real increased time case. That’s about the timeframe when ...
Stationary magnetohydrodynamic flows in curved coaxial channels
The curvilinear geometry of the channel does not significantly affects the gas parameters. For sufficiently high inflow velocities, the velocity of the plasma and gas over the channel, both in the case of its curvilinear configuration and the configuration with the constant average radius, remains constant, and their other main parameters stop changing
To assess, with a peripheral magnetic resonance imaging system (pMRI), the prevalence of bony and soft tissue abnormalities in the knee joints of normal subjects, osteoarthritis (OA) patients, and individuals who have suffered an anterior cruciate ligament (ACL) rupture; and 2) to compare the prevalence among groups. Magnetic resonance (MR) images of 28 healthy, 32 OA, and 26 ACL damaged knees were acquired with a 1.0-T pMRI system. Two radiologists grade the presence and severity of 9 MR image features: cartilage degeneration, osteophytes, subchondral cyst, bone marrow edema, meniscal abnormality, ligament integrity, loose bodies, popliteal cysts, and joint effusion. Ten of 28 healthy (35.7%), 24 of 26 ACL (92.3%), and all OA knees (100%) showed prevalent cartilage defects; 5 healthy (17.9%), 20 ACL (76.9%), and all OA knees (100%) had osteophytes; and 9 normal (32.1%), 21 ACL (80.8%), and 29 OA knees (90.6%) had meniscal abnormalities. One-half of the knees in the OA group (16 of 32, 50%) had subchondral cysts, and almost one-half had bone marrow edema (15 of 32, 46.9%). These features were not common in the ACL group (7.7%, and 11.5%, respectively) and were not observed in healthy knees. The OA group had the most severe cartilage defects, osteophytes, bone marrow edema, subchondral cysts, and meniscal abnormalities; the ACL group showed more severe cartilage defects, osteophytes, and meniscal abnormalities than did normal subjects. The results suggest that knees that have sustained ACL damage have OA-like features, most subjects (19 of 26, 73.1%) could be identified as in the early stage of OA. The prominent abnormalities present in ACL-damaged knees are cartilage defects, osteophytes, and meniscal abnormalities. (author)
Wu, H. [McMaster Univ., Dept. of Medical Sciences, Hamilton, Ontario (Canada)]. E-mail: wuh5@mcmaster.ca; Webber, C. [Hamilton Health Sciences, Dept. of Nuclear Medicine, Hamilton, Ontario (Canada); McMaster Univ., Dept. of Radiology, Hamilton, Ontario (Canada); Fuentes, C.O. [Hamilton Health Sciences, Dept. of Radiology, Hamilton, Ontario (Canada); Benson, R.; Beattie, K. [McMaster Univ., Dept. of Medical Sciences, Hamilton, Ontario (Canada); Adachi, J.D.; Xie, X. [McMaster Univ., Dept. of Medical Sciences, Hamilton, Ontario (Canada); Jabbari, F. [Hamilton Health Sciences, Hamilton, Ontario (Canada); Levy, D.R. [McMaster Univ., Sports Medicine, Dept. of Family Medicine and Dept. of Medicine, Hamilton, Ontario (Canada)
2007-06-15
To assess, with a peripheral magnetic resonance imaging system (pMRI), the prevalence of bony and soft tissue abnormalities in the knee joints of normal subjects, osteoarthritis (OA) patients, and individuals who have suffered an anterior cruciate ligament (ACL) rupture; and 2) to compare the prevalence among groups. Magnetic resonance (MR) images of 28 healthy, 32 OA, and 26 ACL damaged knees were acquired with a 1.0-T pMRI system. Two radiologists grade the presence and severity of 9 MR image features: cartilage degeneration, osteophytes, subchondral cyst, bone marrow edema, meniscal abnormality, ligament integrity, loose bodies, popliteal cysts, and joint effusion. Ten of 28 healthy (35.7%), 24 of 26 ACL (92.3%), and all OA knees (100%) showed prevalent cartilage defects; 5 healthy (17.9%), 20 ACL (76.9%), and all OA knees (100%) had osteophytes; and 9 normal (32.1%), 21 ACL (80.8%), and 29 OA knees (90.6%) had meniscal abnormalities. One-half of the knees in the OA group (16 of 32, 50%) had subchondral cysts, and almost one-half had bone marrow edema (15 of 32, 46.9%). These features were not common in the ACL group (7.7%, and 11.5%, respectively) and were not observed in healthy knees. The OA group had the most severe cartilage defects, osteophytes, bone marrow edema, subchondral cysts, and meniscal abnormalities; the ACL group showed more severe cartilage defects, osteophytes, and meniscal abnormalities than did normal subjects. The results suggest that knees that have sustained ACL damage have OA-like features, most subjects (19 of 26, 73.1%) could be identified as in the early stage of OA. The prominent abnormalities present in ACL-damaged knees are cartilage defects, osteophytes, and meniscal abnormalities. (author)
Possible linkage between neuronal recruitment and flight distance in migratory birds.
Barkan, Shay; Roll, Uri; Yom-Tov, Yoram; Wassenaar, Leonard I; Barnea, Anat
2016-01-01
New neuronal recruitment in an adult animal's brain is presumed to contribute to brain plasticity and increase the animal's ability to contend with new and changing environments. During long-distance migration, birds migrating greater distances are exposed to more diverse spatial information. Thus, we hypothesized that greater migration distance in birds would correlate with the recruitment of new neurons into the brain regions involved with migratory navigation. We tested this hypothesis on two Palearctic migrants - reed warblers (Acrocephalus scirpaceus) and turtle doves (Streptopelia turtur), caught in Israel while returning from Africa in spring and summer. Birds were injected with a neuronal birth marker and later inspected for new neurons in brain regions known to play a role in navigation - the hippocampus and nidopallium caudolateral. We calculated the migration distance of each individual by matching feather isotopic values (δ(2)H and δ(13)C) to winter base-maps of these isotopes in Africa. Our findings suggest a positive correlation between migration distance and new neuronal recruitment in two brain regions - the hippocampus in reed warblers and nidopallium caudolateral in turtle doves. This multidisciplinary approach provides new insights into the ability of the avian brain to adapt to different migration challenges. PMID:26905978
The medical records, radiographic and nuclear scintigraphic findings of 26 racing horses with 27 stress fracture episodes of the humerus, radius, or tibia were reviewed. The purposes of this study were to describe the radiographic and/or scintigraphic features of stress fractures of the humerus, radius, or tibia, and to evaluate the signalment and history of horses in which stress fracture occurred. Stress fractures of the three long bones examined were primarily seen in 2- and 3-year-old male Thoroughbred horses; commonly, the onset of lameness was immediately following training gallops or racing. There were 13 humeral stress fracture episodes in 12 horses. Ten were in the proximal caudolateral cortex, and three were in the distal craniomedial cortex. Radical stress fractures were seen in three horses, all in the midshaft radius. Tibial stress fractures were diagnosed in 11 horses. They were located in the proximal lateral tibia in six horses, the distal caudolateral tibia in three horses, and the midshaft tibia in three horses. Fifteen stress fractures were diagnosed with radiography alone, one was diagnosed with scintigraphy alone, nine were diagnosed with radiographs and scintigraphy, and, in two horses, radiographs were negative, but the scintigraphic findings were consistent with stress fracture
Dysphagia due to anterior cervical osteophytosis: case report
Frederico Miguel Santos Silva Marquez Correia
2014-12-01
Full Text Available The objective of this study is to highlight the possibility of dysphagia induced by anterior cervical osteophytes. When not diagnosed early this condition may be responsible for complications such as severe dysphagia and potential lung aspiration, especially in elderly patients. Analysis of a case report of a 72-year old woman who presented cervical pain and progressive dysphagia. Imaging studies have shown anterior cervical osteophytosis and multilevel degenerative changes in the cervical spine. The patient underwent surgical excision of the cervical anterior osteophytes (C4, C5 and C6 and C5/C6 arthrodesis through anterior approach. The postoperative period was uneventful and symptoms resolved within 2 weeks. Early diagnosis and treatment led to complete resolution, avoiding late and serious complications associated with this pathology in the geriatric population, especially severe and progressive dysphagia and risk of pulmonary aspiration, and the consequent morbidity and mortality associated. A multidisciplinary approach is essential for the correct assessment of this condition
Larsson, S; Englund, M; Struglics, A; Lohmander, L S
2012-01-01
subjects at two time points after meniscectomy. Time point A was on average 18years after meniscectomy, time point B was on average 7.5years later; 74 subjects had SF available from both examinations. We measured SF ARGS by an electrochemiluminescence immunoassay, graded radiographic features of...... between examinations was increased 6- and 4-fold respectively compared to those increasing in SF ARGS (odds ratio (OR) 5.72; 95% confidence interval (CI) 1.53-21.4 and 3.66; 1.01-13.2, respectively). No significant associations were seen between decreasing SF ARGS and progression of osteophytes (OR 0.......88; 0.28-2.78), or for patient-reported outcomes other than KOOS pain. CONCLUSION: Having decreasing levels of SF ARGS over time was associated with an increased risk of loss of joint space and pain worsening, but showed no association with other patient-reported outcomes or osteophyte progression....
Jacobsen, Steffen; Sonne-Holm, Stig; Søballe, Kjeld;
2004-01-01
OBJECTIVE: The aims of this study were to investigate the influence of sex, age and individual physical and occupational factors on the distribution of radiographic features of hip joint osteoarthritis (OA), and to determine the inter-relationships between the primary radiographic OA discriminator......-relationships and correlations to age, sex, body mass index (BMI) and occupational exposure to repeated lifting. RESULTS: Overall, subchondral sclerosis, cysts and osteophytes were more frequently recorded in male hip joints compared to female hip joints, while a decrease in minimum JSW by age was more pronounced...... and progressive in women after the fifth decade compared to men. Applying logistic regression analyses, only age was found to be significantly associated to pathologically reduced minimum JSW (cut off value set at < or =2.0 mm), and the presence of osteophytes and subchondral cysts in both sexes (P...
Capsulorhexis contraction after cataract surgery
Corydon, Charlotte; Lindholt, Michael; Knudsen, Ellen B;
2007-01-01
PURPOSE: To evaluate the reduction in the anterior capsule opening after phacoemulsification, continuous curvilinear capsulorhexis, and implantation of 1 of 2 acrylic intraocular lenses (IOLs). SETTING: Department of Ophthalmology, Vejle Hospital, Vejle, Denmark. METHODS: Eighty-four patients (84...
Perceived neighbourhood environmental attributes associated with adults׳ recreational walking
Sugiyama, Takemi; Cerin, Ester; Owen, Neville;
2014-01-01
crime, and proximity to parks were linearly associated with recreational walking, while curvilinear associations were found for residential density, land use mix, and aesthetics. The observed associations were consistent across countries, except for aesthetics. Using data collected from environmentally...
Miller, Jacob Lee
2015-04-21
An explosive bulk charge, including: a first contact surface configured to be selectively disposed substantially adjacent to a structure or material; a second end surface configured to selectively receive a detonator; and a curvilinear side surface joining the first contact surface and the second end surface. The first contact surface, the second end surface, and the curvilinear side surface form a bi-truncated hemispherical structure. The first contact surface, the second end surface, and the curvilinear side surface are formed from an explosive material. Optionally, the first contact surface and the second end surface each have a substantially circular shape. Optionally, the first contact surface and the second end surface consist of planar structures that are aligned substantially parallel or slightly tilted with respect to one another. The curvilinear side surface has one of a smooth curved geometry, an elliptical geometry, and a parabolic geometry.
Laursen, Keld; Salter, Ammon
2005-01-01
both strategies are curvilinearly (taking an invertedU-shape) related to innovative performance, indicting that some firms may sufferfrom a myopia of protectiveness, relying too heavily on appropriation to the detrimentof other activities.Keywords: Appropriability, Intellectual property rights...
The Use of Linear Programming for Prediction.
Schnittjer, Carl J.
The purpose of the study was to develop a linear programming model to be used for prediction, test the accuracy of the predictions, and compare the accuracy with that produced by curvilinear multiple regression analysis. (Author)
Calcified congenital aneurysm of the left sinus of Valsalva associated with coarctation of the aorta
A case of calcified unruptured congenital aneurysm of the left sinus of Valsalva associated with coarctation of the aorta is presented. Routine chest radiographs demonstrated unusual curvilinear calcifications at the cardiac base which were subsequently demonstrated within the aneurysm. (orig.)
Appendicular bone mass and knee and hand osteoarthritis in Japanese women: a cross-sectional study
Moji Kazuhiko
2002-10-01
Full Text Available Abstract Background It has been reported that there is an inverse association between osteoarthritis (OA and osteoporosis. However, the relationship of bone mass to OA in a Japanese population whose rates of OA are different from Caucasians remains uncertain. Methods We studied the association of appendicular bone mineral density (second metacarpal; mBMD and quantitative bone ultrasound (calcaneus; stiffness index with knee and hand OA among 567 Japanese community-dwelling women. Knee and hand radiographs were scored for OA using Kellgren-Lawrence (K/L scales. In addition, we evaluated the presence of osteophytes and of joint space narrowing. The hand joints were examined at the distal and proximal interphalangeal (DIP, PIP and first metacarpophalangeal/carpometacarpal (MCP/CMC joints. Results After adjusting for age and body mass index (BMI, stiffness index was significantly higher in women with K/L scale, grade 3 at CMC/MCP joint compared with those with no OA. Adjusted means of stiffness index and mBMD were significantly higher in women with definite osteophytes at the CMC/MCP joint compared to those without osteophytes, whereas there were no significant differences for knee, DIP and PIP joints. Stiffness index, but not mBMD, was higher in women with definite joint space narrowing at the CMC/MCP joint compared with those with no joint space narrowing. Conclusions Appendicular bone mass was increased with OA at the CMC/MCP joint, especially among women with osteophytes. Our findings suggest that the association of peripheral bone mass with OA for knee, DIP or PIP may be less clearcut in Japanese women than in other populations.
Cornelius, Jan Frédérick; George, Bernard
2009-01-01
Cervical nerve root compression caused by disco-osteophytic changes is classically operated by anterior transdiscal approach with disc replacement. If compression persists or recurs, reoperation via the same surgical route may be difficult, because of scar tissue and/or implants. An alternative approach may be necessary. We recommend the lateral cervical approach (retrojugular) as salvage operation in such cases. We report a patient with cervical nerve root compression operated by anterior tr...
Pterygoid hamulus bursitis as a cause of craniofacial pain: a case report
Cho, Jin-Yong; Cheon, Kang-Yong; Shin, Dong-Whan; Chun, Won-Bae; Lee, Ho
2013-01-01
Pain on the soft palate and pharynx can originate in several associated structures. Therefore, diagnosis of patients who complain of discomfort in these areas may be difficult and complicated. Pterygoid hamulus bursitis is a rare disease showing various symptoms in the palatal and pharyngeal regions. As such, it can be one of the reported causes of pain in these areas. Treatment of hamular bursitis is either conservative or surgical. If the etiologic factor of bursitis is osteophytic formatio...
Low back pain and degenerative disc disease
Jandrić Slavica; Antić Branislav
2006-01-01
Introduction. Various clinical conditions can cause low back pain, and in most cases it is of a degenerative origin. Degenerative disc disease is a common condition which affects young to middle-aged men and women equally. Changes in the mechanical properties of the disc lead to degenerative arthritis in the intervertebral joints, osteophytes, and narrowing the intervertebral foramen or the spinal canal. Pathophysiology. Degenerative cascade, described by Kirkaldy-Willis, is the widely accept...
Radiographic changes of lumbar spine and pelvis in chronic spinal injury
Shamsa Shariatpanahi
2014-12-01
Conclusion: The most frequent cause of chronic spinal injuries of our patients has been the injury by quiver, it seems our results may not be extended to all patients with spinal cord injury. In lumbar spine radiography of the patients, osteophytes, the quiver and psoriasis like ossifications were mostly seen. In the pelvis x-rays the most changes were hip joint narrowing, sacroiliitis and the heterotopic ossification.
Salih Gulsen
2015-03-01
CONCLUSION: We achieved better cervical lordotic angles at the postoperative period by implanting one-level, two-level, three-level or four-level PEEK cage filled with demineralized bone matrix. Also, the causes of cervical root and or medulla spinalis impingement were different in group1 and 2. While extruded cervical disc impingement was the first pathology in group 1, osteophyte formation was the first pathology in group 2.
Early x-ray diagnosis of coxarthrosis
Lingg, G.; Nebel, G.
Radiological and pathological comparisons on specimen of femur head and neck at autopsy have shown a statistical relationship between osteophytosis of the femoral head and ulcerations of the joint cartilage. Especially, there are highly significant relationships between the length of osteophytes and the diameter of the ulcera. The 'plaque'-sign is shown to be a very sensitive indicator of early arthrosis. So there exist semiquantitative parameters for the X-ray diagnosis of early coxarthrosis.
Maxis, Kelitha; Delalandre, Aline; Martel-Pelletier, Johanne; Pelletier, Jean-Pierre; Duval, Nicolas; Lajeunesse, Daniel
2006-01-01
Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic bone changes with osteophyte formation and abnormal bone remodeling. Two groups of OA patients were identified via the production of variable and opposite levels of prostaglandin E2 (PGE2) or leukotriene B4 (LTB4) by subchondral osteoblasts, PGE2 levels discriminating between low and high subgroups. We studied whether the expression of 5-lipoxygenase (5-LO) or 5-LO-activating protein (FLAP) is responsible...
Update on anterior ankle impingement
Vaseenon, Tanawat; Amendola, Annunziato
2012-01-01
Anterior ankle impingement results from an impingement of the ankle joint by a soft tissue or osteophyte formation at the anterior aspect of the distal tibia and talar neck. It often occurs secondary to direct trauma (impaction force) or repetitive ankle dorsiflexion (repetitive impaction and traction force). Chronic ankle pain, swelling, and limitation of ankle dorsiflexion are common complaints. Imaging is valuable for diagnosis of the bony impingement but not for the soft tissue impingemen...
反変速度-圧力交互時間進行による一般曲線座標系FDTD音場解析手法
大嶋, 拓也; Oshima, Takuya
2006-01-01
Finite-difference time-domain (FDTD) acoustic simulation technique in generalized curvilinear coordinates using contravariant velocity and pressure as variables for two-step leapfrog time marching scheme is presented. The technique excels the conventional generalized curvilinear technique using contravariant velocity, covariant velocity and pressure as variables for three-step time marching, especially in that normal acoustic impedance boundary conditions which are indispensable in practical ...
Large Eddy Simulation of Turbulent Combustion with Chemical Kinetics
Panjwani, Balram
2011-01-01
The present doctoral thesis studies and develops methodologies for turbulent combustion with the Large Eddy Simulation (LES). Three main objectives for present doctoral thesis were.First, development of LES methodology in curvilinear coordinates. LES formulation in curvilinear coordinates can be achieved in two ways, (1) conventional approach, where filtering is performed prior to the transformation, and (2) alternate approach, where filtering is performed after the transformation. In present...
Emotional and Physiological Desensitization to Real-Life and Movie Violence
Mrug, Sylvie; Madan, Anjana; Cook, Edwin W.; Wright, Rex A.
2014-01-01
Youth are exposed to large amounts of violence in real life and media, which may lead to desensitization. Given evidence of curvilinear associations between exposure to violence and emotional distress, we examined linear and curvilinear associations of exposure to real-life and movie violence with PTSD symptoms, empathy, and physiological arousal, as well emotional and physiological reactivity to movie violence. College students (N=209; mean age=18.74) reported on their exposure to real-life ...
Ultrasound transducer shape has no effect on measurements of lumbar multifidus muscle size
Worsley, Peter; Smith, Nick; Warner, Martin; Stokes, Maria
2011-01-01
Objective: Evidence is currently lacking for guidance on ultrasound transducer configuration (shape) when imaging muscle to measure its size. This study compared measurements made of lumbar multifidus on images obtained using curvilinear and linear transducers. Method: Fifteen asymptomatic males (aged 21–32 years) had their right lumbar multifidus imaged at L3. Two transverse images were taken with two transducers (5 MHz curvilinear and 6 MHz linear), and linear and cross-sectional area (...
Multidisciplinary Optimization and Damage Tolerance of Stiffened Structures
Jrad, Mohamed
2015-01-01
The structural optimization of a cantilever aircraft wing with curvilinear spars and ribs and stiffeners is described. The design concept of reinforcing the wing structure using curvilinear stiffening members has been explored due to the development of novel manufacturing technologies like electron-beam-free-form-fabrication (EBF3). For the optimization of a complex wing, a common strategy is to divide the optimization procedure into two subsystems: the global wing optimization which optimize...
奥村, 勇; I., Okumura
2000-01-01
Stress and strain tensors, the equilibrium equation in terms of the stress tensor and transformation laws for the tensors, in orthogonal curvilinear coordinates, are presented. The components of the tensor are defined as covariant components of second-order tensors, which are identical to stress and strain components. The invariants of stress and strain, and the principal stress and strains in the orthogonal curvilinear coordinates are obtained from characteristic polynomials and eigenvalues...
Some shell formulations, in view of their applicability to finite elements
Debongnie, Jean-François
1986-01-01
Surface geometry and shell geometry, in the frame of general tensor calculus. Fundamentals of the theory of thin shells. Expressing strains from curvilinear components of the displacements. Applicability of the preceeding theory to finite elements. Expressing strains from the cartesian components of the displacements. Moderate rotation theory (curvilinear components). Moderate rotation theory (cartesian components). Quasi-plane and almost-plane shells. Shells with shearing strains (cartesian ...
Hybrid Finite Element and Volume Integral Methods for Scattering Using Parametric Geometry
Volakis, John L.; Sertel, Kubilay; Jørgensen, Erik;
2004-01-01
n this paper we address several topics relating to the development and implementation of volume integral and hybrid finite element methods for electromagnetic modeling. Comparisons of volume integral equation formulations with the finite element-boundary integral method are given in terms of...... accuracy and computing resources. We also discuss preconditioning and parallelization of the multilevel fast multipole method, and propose higher-order basis functions for curvilinear quadrilaterals and volumetric basis functions for curvilinear hexahedra. The latter have the desirable property of...
MR imaging of cervical disc disease
Since magnetic resonance imaging (MRI) technology has been greatly improved, MRI for cervical disc disease has become widely used in many facilities. Among non-invasive procedures, MRI is regarded as one of the most useful ones. Conventional myelography, CT myelography, and MRI were performed on 10 patients with cervical disc disease. The authors discussed the correlation between conventional myelography, CT myelography, and MRI as regards their ability to determine the localization and the laterality of disc protrusion and osteophyte. In our MRI study, we use both short-echo (SE) images and GRASS images. The parameters of our GRASS included 5 mm-thick sections. TR=200, TE=20, and flip angles of 10deg. This pulse sequence generates images with high signal cerebrospinal fluid (CSF), resulting in a high-contrast CSF-spinal cord, osteophyte, and disc protrusion. As yet, although it easily shows the localization and laterality of the disc and/or osteophyte, image quality of the GRASS is not yet sufficient to allow us to evaluate detailed deformity of the spinal cord and nerve root. The authors stress the usefulness of this GRASS image for the evaluation of suspected cervical disc disease. (author)
Bestami Yilmaz
2011-01-01
Full Text Available This study is carried out with five Turkish shepherd dog (Canis familiaris, five curly sheep (Ovis aries and five native hair goats (Capra hircus which were adult and in different gender, macroanatomical, subgross and comprehensive research of sensible nerves (n. innervating shoulder joint capsule was aimed. The shoulder joint capsule was found to be innervated by axillary and suprascapular nerves in Turkish shepherd dog, curly sheep and native hair goats in macroscopic and subgross analysis. The articular branch of axillary nerve was detected to generally terminate in joint capsule with 3 branches from caudolateral and suprascapular nerve was detected to terminate in joint capsule with 1 branch from lateral. In conclusion, number of the articular branches was found to be more in Turkish shepherd dogs and native hair goats compared to curly sheep. These differences were considered to be related to stated two species being more athletic and faster than curly sheep.
The Neural Basis of Long-Distance Navigation in Birds.
Mouritsen, Henrik; Heyers, Dominik; Güntürkün, Onur
2016-01-01
Migratory birds can navigate over tens of thousands of kilometers with an accuracy unobtainable for human navigators. To do so, they use their brains. In this review, we address how birds sense navigation- and orientation-relevant cues and where in their brains each individual cue is processed. When little is currently known, we make educated predictions as to which brain regions could be involved. We ask where and how multisensory navigational information is integrated and suggest that the hippocampus could interact with structures that represent maps and compass information to compute and constantly control navigational goals and directions. We also suggest that the caudolateral nidopallium could be involved in weighing conflicting pieces of information against each other, making decisions, and helping the animal respond to unexpected situations. Considering the gaps in current knowledge, some of our suggestions may be wrong. However, our main aim is to stimulate further research in this fascinating field. PMID:26527184
A Note on Natural Coordinates and Frenet Frames
ZHOU Xiaozhou; ZHU Keqin
2007-01-01
This paper discusses the relationship between natural coordinates in fluid mechanics and orthogonal curvilinear coordinates. Since orthogonal curvilinear coordinates have some excellent mathematical properties, natural coordinates can be applied more widely if they can be transformed to orthogonal curvilinear coordinates. Frenet formulas which describe the differential properties of natural coordinates were compared with the derivative formulas of orthogonal curvilinear coordinates to show that natural coordinates are not generally orthogonal curvilinear coordinates. A method was introduced to transform natural coordinates into orthogonal curvilinear coordinates by rotating the normal planes of the natural coordinates about the streamlines. The transformation is true as long as the natural coordinates satisfy several equations. Vorticity decomposition in the natural coordinates is used to show that these conditional equations are satisfied only if the streamlines are perpendicular to the vortexlines on every given point in the flow field. These equations apply in both planar flows and axisymmetric flows without a circumferential velocity component, but do not apply in some 3-D flows such as Beltrami flow.
The laparotomy incision: a technique to facilitate capsulorhexis in microincision cataract surgery.
O'Connor, Jeremy C; O'Connell, Eamon D; Sciscio, Andrea; Mulhern, Mark G
2008-01-01
Microincision cataract surgery is a new technique in the development of cataract surgery and is not without difficulties. Creation of the continuous curvilinear capsulorhexis as performed in conventional coaxial phacoemulsification surgery does not apply as readily. The authors describe a method for initiating the continuous curvilinear capsulorhexis (the laparotomy incision) using only an inexpensive 25-gauge bent needle cystototome. The technique involves a long linear incision in the anterior capsule down the belly of the lens as a means of initiating the capsulorhexis. Advantages of the technique include the creation of a large capsular flap, which allows easier completion of the continuous curvilinear capsulorhexis through a smaller range of movement, avoiding "oar locking" in the small incision and creation of striae in the cornea. It also allows better maintenance of anterior chamber depth, minimizing risk of radial tears. PMID:19065989
Methods of forming a fluidized bed of circulating particles
Marshall, Douglas W.
2011-05-24
There is disclosed an apparatus for forming a fluidized bed of circulating particles. In an embodiment, the apparatus includes a bottom portion having a sidewall, the sidewall defining a curvilinear profile, and the bottom portion configured to contain a bed of particles; and a gas inlet configured to produce a column of gas to carry entrained particles therein. There is disclosed a method of forming a fluidized bed of circulating particles. In an embodiment, the method includes positioning particles within a bottom portion having a sidewall, the sidewall defining a curvilinear profile; producing a column of gas directed upwardly through a gas inlet; carrying entrained particles in the column of gas to produce a fountain of particles over the fluidized bed of circulating particles and subside in the particle bed until being directed inwardly into the column of gas within the curvilinear profile.
Design of a new nozzle for direct current plasma guns with improved spraying parameters
Jankovic, M.; Mostaghimi, J.; Pershin, V.
2000-03-01
A new design is proposed for direct current plasma spray gas-shroud attachments. It has curvilinearly shaped internal walls aimed toward elimination of the cold air entrainment, recorded for commercially available conical designs of the shrouded nozzle. The curvilinear nozzle design was tested; it proved to be capable of withstanding high plasma temperatures and enabled satisfactory particle injection. Parallel measurements with an enthalpy probe were performed on the jet emerging from two different nozzles. Also, corresponding calculations were made to predict the plasma flow parameters and the particle parameters. Adequate spray tests were performed by spraying iron-aluminum and MCrAlY coatings onto stainless steel substrates. Coating analyses were performed, and coating qualities, such as microstructure, open porosity, and adhesion strength, were determined. The results indicate that the coatings sprayed with a curvilinear nozzle exhibited lower porosity, higher adhesion strength, and an enhanced microstructure.
Visser, A W; Mertens, B; Reijnierse, M; Bloem, J L; de Mutsert, R; le Cessie, S; Rosendaal, F R; Kloppenburg, M
2016-01-01
Objective To investigate which structural MR abnormalities discriminate symptomatic knee osteoarthritis (OA), taking co-occurrence of abnormalities in all compartments into account. Methods The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort aged 45–65 years. In 1285 participants (median age 56 years, 55% women, median body mass index (BMI) 30 kg/m2), MRI of the right knee were obtained. Structural abnormalities (osteophytes, cartilage loss, bone marrow lesions (BMLs), subchondral cysts, meniscal abnormalities, effusion, Baker's cyst) at 9 patellofemoral and tibiofemoral locations were scored following the knee OA scoring system. Symptomatic OA in the imaged knee was defined following the American College of Rheumatology criteria. Logistic ridge regression analyses were used to investigate which structural abnormalities discriminate best between individuals with and without symptomatic OA, crude and adjusted for age, sex and BMI. Results Symptomatic knee OA was present in 177 individuals. Structural MR abnormalities were highly frequent both in individuals with OA and in those without. Baker's cysts showed the highest adjusted regression coefficient (0.293) for presence of symptomatic OA, followed by osteophytes and BMLs in the medial tibiofemoral compartment (0.185–0.279), osteophytes in the medial trochlear facet (0.262) and effusion (0.197). Conclusions Baker's cysts discriminate best between individuals with and without symptomatic knee OA. Structural MR abnormalities, especially in the medial side of the tibiofemoral joint and effusion, add further in discriminating symptomatic OA. Baker's cysts may present as a target for treatment. PMID:27252896
Agreement in the Interpretation of Magnetic Resonance Images of the Lumbar Spine
Background: Correlation between clinical features and magnetic resonance imaging (MRI) findings is essential in low-back-pain patients. Most previous studies have analyzed concordance in the interpretation of lumbar MRI among a few radiologists who worked together. This may have overestimated concordance. Purpose: To evaluate intra- and interobserver agreement in the interpretation of lumbar MRI performed in an open 0.2T system. Material and Methods: Seven radiologists from two different geographic settings in Spain interpreted the lumbar MRIs of 50 subjects representative of the general Danish population aged 40 years. The radiologists interpreted the images in routine clinical practice, having no knowledge of the clinical and demographic characteristics of the subjects and blinded to their colleagues' assessments. Six of the radiologists evaluated the same MRIs 14 days later, having no knowledge of the previous results. Data on the existence of disc degeneration, high-intensity zones, disc contour, Schmorl nodes, Modic changes, osteophytes, spondylolisthesis, and spinal stenosis were collected in the Nordic Modic Consensus Group Classification form. Intra- and interobserver agreement was analyzed for variables with a prevalence =10% and =90% by means of the kappa statistic. Results: Intra- and interobserver agreement was excellent for variables related to Modic changes, and fair to good for disc contour, high-intensity zones, and Schmorl nodes. The evaluations for disc degeneration and osteophytes were found to have fair to good intraobserver agreement and poor interobserver agreement. The agreement for the evaluations of spondylolisthesis and spinal stenosis was not analyzed because they were observed in <10% of reports. Conclusion: Images from 0.2T MRIs appear to lead to good agreement in the reporting of disc contour, high-intensity zones, Schmorl nodes, and, in particular, Modic changes, suggesting that they can possibly be reliably used for clinical research
Takahashi, Tomoki [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Kumamoto University, Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Kumamoto (Japan); Tins, Bernhard; McCall, Iain W.; Ashton, Karen [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Trust, Department of Diagnostic Imaging, Oswestry, Shropshire (United Kingdom); Richardson, James B. [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); RJAH Orthopaedic Hospital, Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Takagi, Katsumasa [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Kumamoto Aging Research Institute, Kumamoto (Japan)
2006-01-01
To relate the magnetic resonance imaging (MRI) appearance of autologous chondrocyte implantation (ACI) in the knee in the 1st postoperative year with other knee features on MRI and with clinical outcome. Forty-nine examinations were performed in 49 patients at 1 year after ACI in the knee. Forty-one preoperative magnetic resonance (MR) examinations were also available. The grafts were assessed for smoothness, thickness in comparison with that of adjacent cartilage, signal intensity, integration to underlying bone and adjacent cartilage, and congruity of subchondral bone. Presence of overgrowth and bone marrow appearance beneath the graft were also assessed. Presence of osteophyte formation, further cartilage defects, appearance of the cruciate ligaments and the menisci were also recorded. An overall graft score was constructed, using the graft appearances. This was correlated with the knee features and the Lysholm score, a clinical self-assessment score. The data were analysed by a Kruskal-Wallis H test followed by a Mann-Whitney U test with Bonferroni correction as post-hoc test. Of 49 grafts, 32 (65%) demonstrated complete defect filling 1 year postoperatively. General overgrowth was seen in eight grafts (16%), and partial overgrowth in 13 grafts (26%). Bone marrow change underneath the graft was seen; oedema was seen in 23 grafts (47%), cysts in six grafts (12%) and sclerosis in two grafts (4%). Mean graft score was 8.7 (of maximal 12) (95% CI 8.0-9.5). Knees without osteophyte formation or additional other cartilage defects (other than the graft site) had a significantly higher graft score than knees with multiple osteophytes (P=0.0057) or multiple further cartilage defects (P=0.014). At 1 year follow-up improvement in the clinical scores was not significantly different for any subgroup. (orig.)
Cervical disc hernia operations through posterior laminoforaminotomy
Coskun Yolas
2016-01-01
Full Text Available Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years. Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%. On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.
Agreement in the Interpretation of Magnetic Resonance Images of the Lumbar Spine
Kovacs, F.M. (Dept. Cientfico, Fundacin Kovacs, Palma de Majorca (Spain)); Royuela, A. (Spanish Back Pain Research Network, Fundacin Kovacs, Palma de Majorca (Spain)); Jensen, T.S. (Back Research Center, Backcenter Funen, Ringe (Denmark)) (and others)
2009-06-15
Background: Correlation between clinical features and magnetic resonance imaging (MRI) findings is essential in low-back-pain patients. Most previous studies have analyzed concordance in the interpretation of lumbar MRI among a few radiologists who worked together. This may have overestimated concordance. Purpose: To evaluate intra- and interobserver agreement in the interpretation of lumbar MRI performed in an open 0.2T system. Material and Methods: Seven radiologists from two different geographic settings in Spain interpreted the lumbar MRIs of 50 subjects representative of the general Danish population aged 40 years. The radiologists interpreted the images in routine clinical practice, having no knowledge of the clinical and demographic characteristics of the subjects and blinded to their colleagues' assessments. Six of the radiologists evaluated the same MRIs 14 days later, having no knowledge of the previous results. Data on the existence of disc degeneration, high-intensity zones, disc contour, Schmorl nodes, Modic changes, osteophytes, spondylolisthesis, and spinal stenosis were collected in the Nordic Modic Consensus Group Classification form. Intra- and interobserver agreement was analyzed for variables with a prevalence =10% and =90% by means of the kappa statistic. Results: Intra- and interobserver agreement was excellent for variables related to Modic changes, and fair to good for disc contour, high-intensity zones, and Schmorl nodes. The evaluations for disc degeneration and osteophytes were found to have fair to good intraobserver agreement and poor interobserver agreement. The agreement for the evaluations of spondylolisthesis and spinal stenosis was not analyzed because they were observed in <10% of reports. Conclusion: Images from 0.2T MRIs appear to lead to good agreement in the reporting of disc contour, high-intensity zones, Schmorl nodes, and, in particular, Modic changes, suggesting that they can possibly be reliably used for clinical
To relate the magnetic resonance imaging (MRI) appearance of autologous chondrocyte implantation (ACI) in the knee in the 1st postoperative year with other knee features on MRI and with clinical outcome. Forty-nine examinations were performed in 49 patients at 1 year after ACI in the knee. Forty-one preoperative magnetic resonance (MR) examinations were also available. The grafts were assessed for smoothness, thickness in comparison with that of adjacent cartilage, signal intensity, integration to underlying bone and adjacent cartilage, and congruity of subchondral bone. Presence of overgrowth and bone marrow appearance beneath the graft were also assessed. Presence of osteophyte formation, further cartilage defects, appearance of the cruciate ligaments and the menisci were also recorded. An overall graft score was constructed, using the graft appearances. This was correlated with the knee features and the Lysholm score, a clinical self-assessment score. The data were analysed by a Kruskal-Wallis H test followed by a Mann-Whitney U test with Bonferroni correction as post-hoc test. Of 49 grafts, 32 (65%) demonstrated complete defect filling 1 year postoperatively. General overgrowth was seen in eight grafts (16%), and partial overgrowth in 13 grafts (26%). Bone marrow change underneath the graft was seen; oedema was seen in 23 grafts (47%), cysts in six grafts (12%) and sclerosis in two grafts (4%). Mean graft score was 8.7 (of maximal 12) (95% CI 8.0-9.5). Knees without osteophyte formation or additional other cartilage defects (other than the graft site) had a significantly higher graft score than knees with multiple osteophytes (P=0.0057) or multiple further cartilage defects (P=0.014). At 1 year follow-up improvement in the clinical scores was not significantly different for any subgroup. (orig.)
L V Sizova
2008-01-01
Full Text Available Objective. To assess significance of arthrosonography in diagnosis of in knee joint changes in patients with early rheumatoid arthritis (RA. Material and methods. 44 patients with early RA aged 19 to 73 years were examined. 29,5% of pts had early RA without primary osteoarthritis (OA, 70,5% had early RA with primary OA. Ultrasonography of knee joints was performed with Diasonics (USA, 1997 by the linear sensor with frequency of 7 MHz. The protocol of ultrasonic examination of knee joints was filled for each pt. Results. Clinical signs of of knee joint synovitis have been revealed in 61,5% of pts with early RA without primary OA, and in 80,6% of pts with early RA with primary OA, ultrasonic - in 100% of pts. Intraarticular knee joint effusion resulted in increase of suprapatellar bursa and lateral recesses size. Extraarticular inflammation was frequently shown by thickening of semymemranous muscles tendons, especially in pts with the early RA with primary OA (p<0,005. Degenerative changes in the group of pts with primary OA were more expressed in early RA and usually accompanied by non-uniform decrease of cartilage thickness and occurrence of osteophytes while cartilage in pts with early RA without primary OA had normal thickness or thickening because of swelling, and osteophytes were absent. Conclusion. Prevalence of knee joint intraarticular and extraarticular inflammatory changes over degenerate changes (symmetric thickening of the synovium, primary increase of the sizes of suprapatellar bursa and lateral recesses because of effusion, thickening of tendons of knee joints at the normal or increased thickness of cartilage because of inflammation can be considered sonographic sign of early RA. In pts with early RA coincided with primary OA these changes were usually found in combination with non-uniform decrease of cartilage thickness. In case of cartilage inflammatory edema, detection of osteophytes allows to confirm presence of OA in pts with
Objective. To evaluate the efficiency of DVT in comparison with OPG in the assessment of bony condylar changes in patients of TMJ pain. Methods. 100 temporomandibular joints of 62 patients with the complaint of temporomandibular joint pain were included in the study. DVT and OPG radiographs were taken for all the 100 joints. Three observers interpreted the DVT and OPG radiograph for the bony changes separately for two times with an interval of one week. The bony changes seen in the condyle were given coding from 0 to 6. (0: Normal, 1: Erosion, 2: Flattening, 3: Osteophyte, 4: Sclerosis, 5: Resorption, and 6: other changes). Interobserver and intra observer variability was assessed with one-way Anoka statistics. Z test was used to see the significant difference between OPG and DVT. Results. In the present study the inter examiner reliability for Og and DVT was 0.903 and 0.978, respectively. Intra examiner reliability for OPG and DVT was 0.908 and 0.980, respectively. The most common condylar bony change seen in OPG and DVT was erosion followed by flattening and osteophyte. There was significant difference between OPG and DVT in detecting erosion and osteophytes. The other changes observed in our study were Elys cyst, pointed condyle, and bifid condyle. All the bony changes are more commonly seen in females than males. Conclusion. DVT provides more valid and accurate information on condylar bony changes. The DVT has an added advantage of lesser radiation exposure to the patient and cost effectiveness and could be easily accessible in a dental hospital
Cervical disc hernia operations through posterior laminoforaminotomy
Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit
2016-01-01
Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.
Jonathan C Rawstorn
Full Text Available Use of the Global Positioning System (GPS for quantifying athletic performance is common in many team sports. The effect of running velocity on measurement validity is well established, but the influence of rapid directional change is not well understood in team sport applications. This effect was systematically evaluated using multidirectional and curvilinear adaptations of a validated soccer simulation protocol that maintained identical velocity profiles. Team sport athletes completed 90 min trials of the Loughborough Intermittent Shuttle-running Test movement pattern on curvilinear, and multidirectional shuttle running tracks while wearing a 5 Hz (with interpolated 15 Hz output GPS device. Reference total distance (13 200 m was systematically over- and underestimated during curvilinear (2.61±0.80% and shuttle (-3.17±2.46% trials, respectively. Within-epoch measurement uncertainty dispersion was widest during the shuttle trial, particularly during the jog and run phases. Relative measurement reliability was excellent during both trials (Curvilinear r = 1.00, slope = 1.03, ICC = 1.00; Shuttle r = 0.99, slope = 0.97, ICC = 0.99. Absolute measurement reliability was superior during the curvilinear trial (Curvilinear SEM = 0 m, CV = 2.16%, LOA ± 223 m; Shuttle SEM = 119 m, CV = 2.44%, LOA ± 453 m. Rapid directional change degrades the accuracy and absolute reliability of GPS distance measurement, and caution is recommended when using GPS to quantify rapid multidirectional movement patterns.
Footballer's ankle: a case report
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2002-01-01
@@ Footballer' s ankle is anterior bony spur or anterior impingement symptom of the ankle with anterior ankle pain, limited and painful dorsiflexion. The cause is commonly seen in athletes and dancers, and is probably due to repetitive minor trauma. The condition was firstly described by Morris;1 McMurray2 reported good results from excision of the spurs, naming it footballer's ankle. Opening resection of osteophytes of the anterior tibial and superior talar is an effective treatment for anterior impingement of the ankle.
Hip dysplasia in a litter of Domestic Shorthair cats
A 14-month-old female Domestic Shorthair cat was presented with bilaterally shallow acetabuli, flattened femoral heads, and subluxation of the hips, changes consistent with hip dysplasia. Follow-up radiographs showed additional osteophyte formation and remodeling of both coxofemoral joints. Two of her female littermate exhibited the same condition. Pelvic examinations of a male from the same litter as well as those of the queen and two other 3-year-old offspring were normal. This report demonstrates that it is likely that genetics plays a role in felinehip dysplasia, although further detailed reports and similar investigations of related cats affected by this condition are needed
Dable, Rajani A.; Wasnik, Pradnya B.; Nagmode, Sunilkumar L.; Ali, Mukkaram Faridi
2013-01-01
Herein, presenting a case of a 42-year-old female with the chief complaint of dysphagia. The problem was assumed to be of dental origin, due to the onset of dental pain followed by dysphagia. A cervical radiograph revealed the presence of osteophytic lipping which proved to be the cause of dysphagia. Confusing and overlapping disease entities showing similar symptoms need thorough investigation. Dysphagia related to cervical spondylosis may have a direct connection with the person's occupation. Dentistry is considered a potentially hazardous occupation with regard to musculoskeletal disorders. However, additional studies are required to understand the occupational hazards faced by dentists. PMID:24250178
Rajani A Dable
2013-01-01
Full Text Available Herein, presenting a case of a 42-year-old female with the chief complaint of dysphagia. The problem was assumed to be of dental origin, due to the onset of dental pain followed by dysphagia. A cervical radiograph revealed the presence of osteophytic lipping which proved to be the cause of dysphagia. Confusing and overlapping disease entities showing similar symptoms need thorough investigation. Dysphagia related to cervical spondylosis may have a direct connection with the person′s occupation. Dentistry is considered a potentially hazardous occupation with regard to musculoskeletal disorders. However, additional studies are required to understand the occupational hazards faced by dentists.
When degraded, type II collagen, which is contained in large quantities in the cartilage and intervertebral discs, produces a C-terminal peptide (type II collagen C terminal telopeptide, CTX-II), which is excreted in the urine. It has been reported that CTX-II is useful for evaluating the severity of cartilage degeneration and abrasion in the hip and knee joints, but shows no correlation with the severity of degeneration of intervertebral discs, which are mostly composed of type II collagen. The present study was performed to clarify whether urinary CTX-II was correlated with intervertebral X-ray findings. A cross-sectional study was performed to clarify correlations between urinary CTX-II and the progression of degeneration of each intervertebral disc on lumbar X-P films. The subjects of this study were 100 patients (400 intervertebral discs) aged≥40 years. They visited this hospital for the first time because of low backache. Intervertebral disc height, osteophyte length and Kellgren-Lawrence classification were measured to evaluate the degree of lumbar disc degeneration on X-ray films. The second freshly voided urine was used for measuring urinary CTX-II. The measurement results were investigated for correlations with disc height, osteophyte length, age, sex, body mass index (BMI), and lumbar MRI findings by cross-sectional analysis. The t-test and Kruskal-Wallis-test were used for statistical analysis of data. Urinary CTX-II was not correlated with age or BMI but was significantly higher in females than in males. It was only correlated with the degeneration of L2/3 and 3/4 discs and showed a significant difference between lower, medium, and higher disc groups. It was not correlated with osteophyte length or lumbar MRI findings. Urinary CTX-II was only correlated with L2/3 and 3/4 disc degeneration. This was presumably ascribable to the focus and distance during radiography. Osteophyte formation is a phenomenon secondary to intervertebral disc degeneration