Joaquín Pérez Rendón
2011-04-01
Full Text Available El Hallux Abductus Valgus (HAV, comúnmente llamado juanete, se define como la desviación lateral del primer dedo del pie y su rotación en valgo. Su origen es multifactorial, existiendo etiología patomecánica de base: hiperpronación subastragalina, excesiva longitud del primer metatarsiano y/o del primer dedo, o la insuficiencia del músculo peroneo largo. Estadísticamente, afecta más al sexo femenino que al masculino, y, en relación al baile flamenco, hay dos factores que se han asociado con una alta incidencia: uso del calzado de tacón y puntera estrecha, y ciertas modalidades del gesto deportivo.Mediante estudio observacional transversal realizado en diferentes academias de flamenco de Andalucía, Área Clínica de Podología de la Universidad de Sevilla y centros privados de Investigación y Podología, sobre 32 bailaoras de flamenco, se determina que existe una muy alta prevalencia de hallux abductus valgus en la bailaora profesional de flamenco.The hallux abductus valgus (HAV, commonly known as bunion, is defined as first toe lateral curvature and its rotation in valgus. Its origin can be derived from multiple factors, such as the existence of pathomechanics etiology: subastragalina joint hiperpronation, excessive length of first metatarsal and/or first toe, or peroneus longus muscle failure. Statiscally, it affects more to females than males, and as regards flamenco dance there are two factors which are closely related to such high levels of deformity: high-heeled shoes and narrow toe cap use, and some sports gesture methods.
Radiographic measurements of hallux angles: a review of current techniques.
Srivastava, Subodh; Chockalingam, N; El Fakhri, Tarek
2010-03-01
Radiographic angles are commonly used in patients with hallux valgus deformity to assess the severity, plan surgery, assess outcome and compare results. Many different manual methods have been used, but are prone to error. More recently computer-assisted methods using software have become available. To review the different methods that have been used to measure radiographic angles in hallux valgus. A general literature search using relevant key words was undertaken using databases such as Medline, Embase, Cinahl and Cochrane Library. REVIEW FINDINGS AND DISCUSSION: The manual methods used are prone to errors. The reliability can be improved by using standardised radiographic technique and measurement technique using specific reference points. Computer-assisted methods using software, might improve reliability of measurements. Further studies are needed to assess if these methods are easy to use, and to compare different software's that are available. Specifically designed software for the foot might further improve the reliability of radiographic measurements in hallux valgus. Copyright (c) 2009 Elsevier Ltd. All rights reserved.
Approach for measuring the angle of hallux valgus
Jin Zhou
2013-01-01
Materials and Methods: Fifteen age, body weight, and height matched male students were included and those with foot disorders, deformities, or injuries were excluded from the study. The dorsal protrusions of the first metatarsal and the hallux were marked by palpating from three experienced observers; then their barefoot model in standing was collected by a three dimensional laser scanning system. The AoH was defined in the X-Y plane by the angle between the line joining the marks of centre of head and centre of base of metatarsal shaft and the one connecting the marks of the centre of metatarsal head and the hallux. The same procedure was repeated a week later. Besides, other measures based on the footprint, outline, and the radiography were also available for comparisons. Paired t-test, linear regression, and reliability analysis were applied for statistical analysis with significant level of 0.05 and 95% confidence interval. Results: There were no significant differences recorded between the new method and the radiographic method ( P = 0.069. The AoH was superior to the methods of footprint and outline and it displayed a relative higher correlation with the radiographic method (r = 0.94, r2 = 0.89. Moreover both the inter and intraobserver reliabilities of this method were proved to be good. Conclusion: This new method can be used for hallux valgus inspection and evaluation.
Bipartite hallucal sesamoid bones: relationship with hallux valgus and metatarsal index
Munuera, Pedro V.; Dominguez, Gabriel [University of Seville, Department of Podiatrics, Seville (Spain); Centro Docente de Fisioterapia y Podologia, Departamento de Podologia, Seville (Spain); Reina, Maria; Trujillo, Piedad [Centro Docente de Fisioterapia y Podologia, Departamento de Podologia, Seville (Spain)
2007-11-15
The objective was to relate the incidence of the partition of the hallucal sesamoid bones to the size of the first metatarsal and the hallux valgus deformity. In a sample of 474 radiographs, the frequency of appearance of bipartite sesamoids was studied. The length and relative protrusion of the first metatarsal, and the hallux abductus angle, were measured and compared between the feet with and without sesamoid partition. The results showed that 14.6% of the feet studied had at least one partite sesamoid, that the sesamoid most frequently divided was the medial, and that unilateral partition was the most common. No difference was found in the incidence of partite sesamoids between men and women, or between left and right feet. Protrusion and length of the first metatarsal are greater in feet with partite sesamoids than in feet without this condition. A significantly higher incidence of bipartite medial sesamoid was obtained in feet with hallux valgus compared with normal feet. (orig.)
Radiographic angles in hallux valgus: Comparison between protractor and iPhone measurements.
Meng, Hong-Zheng; Zhang, Wei-Lin; Li, Xiu-Cheng; Yang, Mao-Wei
2015-08-01
Radiographic angles are used to assess the severity of hallux valgus deformity, make preoperative plans, evaluate outcomes after surgery, and compare results between different methods. Traditionally, hallux valgus angle (HVA) has been measured by using a protractor and a marker pen with hardcopy radiographs. The main objective of this study is to compare HVA measurements performed using a smartphone and a traditional protractor. The secondary objective was to compare the time taken between those two methods. Six observers measured major HVA on 20 radiographs of hallux valgus deformity with both a standard protractor and an Apple iPhone. Four of the observers repeated the measurements at least a week after the original measurements. The mean absolute difference between pairs of protractor and smartphone measurements was 3.2°. The 95% confidence intervals for intra-observer variability were ±3.1° for the smartphone measurement and ±3.2° for the protractor method. The 95% confidence intervals for inter-observer variability were ±9.1° for the smartphone measurement and ±9.6° for the protractor measurement. We conclude that the smartphone is equivalent to the protractor for the accuracy of HVA measurement. But, the time taken in smartphone measurement was also reduced.
Radiographic Relevance of the Distal Medial Cuneiform Angle in Hallux Valgus Assessment.
Hatch, Daniel J; Smith, Abigail; Fowler, Troy
2016-01-01
The angle formed by the distal articular facet of the medial cuneiform has been evaluated and discussed by various investigators. However, no consistent method has been available to radiograph and measure this entity. The wide variability of the angle is not conducive to comparative analysis. Additionally, investigators have noted that the angles observed (obliquity) vary greatly because of changes in radiographic angle, foot position, rotation of the first ray, and declination of the first metatarsal. Recognizing that these variables exist, we propose a reproducible assessment using digital radiography and application of deformity of correction principles. Our results have indicated a mean distal medial cuneiform angle of 20.69° in normal feet, 23.51° with moderate hallux valgus, and 20.41° with severe hallux valgus deformity. The radiograph beam was kept at 15° from the coronal plane. An inverse relationship was found between the distal medial cuneiform angle and bunion severity. This was in contrast to our expected hypothesis. The overall angle of the first metatarsal-medial cuneiform did, however, correlate with the severity of the bunion deformity (p positioning, and soft tissue imbalances. Perhaps, 3-dimensional computed tomography imaging will provide better insight into this entity.
Kundi Michael
2009-12-01
Full Text Available Abstract Background Wearing shoes of insufficient length during childhood has often been cited as leading to deformities of the foot, particularly to the development of hallux valgus disorders. Until now, these assumptions have not been confirmed through scientific research. This study aims to investigate whether this association can be statistically proven, and if children who wear shoes of insufficient length actually do have a higher risk of a more pronounced lateral deviation of the hallux. Methods 858 pre-school children were included in the study. The study sample was stratified by sex, urban/rural areas and Austrian province. The hallux angle and the length of the feet were recorded. The inside length of the children's footwear (indoor shoes worn in pre-school and outdoor shoes were assessed. Personal data and different anthropometric measurements were taken. The risk of hallux valgus deviation was statistically tested by a stepwise logistic regression analysis and the relative risk (odds ratio for a hallux angle ≥ 4 degrees was calculated. Results Exact examinations of the hallux angle could be conducted on a total of 1,579 individual feet. Only 23.9% out of 1,579 feet presented a straight position of the great toe. The others were characterized by lateral deviations (valgus position at different degrees, equalling 10 degrees or greater in 14.2% of the children's feet. 88.8% of 808 children examined wore indoor footwear that was of insufficient length, and 69.4% of 812 children wore outdoor shoes that were too short. A significant relationship was observed between the lengthwise fit of the shoes and the hallux angle: the shorter the shoe, the higher the value of the hallux angle. The relative risk (odds ratio of a lateral hallux deviation of ≥ 4 degrees in children wearing shoes of insufficient length was significantly increased. Conclusions There is a significant relationship between the hallux angle in children and footwear that is
Park, Chul Hyun; Cho, Jae Ho; Moon, Jeong Jae; Lee, Woo Chun
2016-01-01
No previous study has reported the results of double metatarsal osteotomy for adult hallux valgus deformity with an increased distal metatarsal articular angle (DMAA). The purpose of the present study was to evaluate the results after double metatarsal osteotomy in adult patients with incongruent hallux valgus deformity. We retrospectively reviewed 16 cases of consecutive first metatarsal double metatarsal osteotomy without lateral soft tissue release in 14 patients with symptomatic hallux valgus associated with an increased DMAA (≥15° after proximal chevron osteotomy on intraoperative radiographs). Clinical results were assessed using the American Orthopaedic Foot and Ankle Society scale and the visual analog scale. The radiographic results were assessed over time, and changes in the DMAA and the relative length of the first metatarsal were assessed by measuring each value preoperatively and at the last follow-up visit. The American Orthopaedic Foot and Ankle Society and visual analog scale scores were significantly improved after surgery. The hallux valgus angle and intermetatarsal angle were stabilized >3 months after surgery. The sesamoid position did not increase significantly beyond the immediate postoperative period. The mean DMAA was corrected from 21.6° (range 15° to 29°) preoperatively to 11.1° (range -2° to 17°) at the last follow-up visit. The mean amount of shortening of the first metatarsal after surgery was 5.5 (range 4 to 7) mm. In conclusion, double metatarsal osteotomy without lateral soft tissue release in adult hallux valgus deformity results in high postoperative recurrence and complication rates. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.
Descriptive quantitative analysis of hallux abductovalgus transverse plane radiographic parameters.
Meyr, Andrew J; Myers, Adam; Pontious, Jane
2014-01-01
Although the transverse plane radiographic parameters of the first intermetatarsal angle (IMA), hallux abductus angle (HAA), and the metatarsal-sesamoid position (MSP) form the basis of preoperative procedure selection and postoperative surgical evaluation of the hallux abductovalgus deformity, the so-called normal values of these measurements have not been well established. The objectives of the present study were to (1) evaluate the descriptive statistics of the first IMA, HAA, and MSP from a large patient population and (2) to determine an objective basis for defining "normal" versus "abnormal" measurements. Anteroposterior foot radiographs from 373 consecutive patients without a history of previous foot and ankle surgery and/or trauma were evaluated for the measurements of the first IMA, HAA, and MSP. The results revealed a mean measurement of 9.93°, 17.59°, and position 3.63 for the first IMA, HAA, and MSP, respectively. An advanced descriptive analysis demonstrated data characteristics of both parametric and nonparametric distributions. Furthermore, clear differentiations in deformity progression were appreciated when the variables were graphically depicted against each other. This could represent a quantitative basis for defining "normal" versus "abnormal" values. From the results of the present study, we have concluded that these radiographic parameters can be more conservatively reported and analyzed using nonparametric descriptive and comparative statistics within medical studies and that the combination of a first IMA, HAA, and MSP at or greater than approximately 10°, 18°, and position 4, respectively, appears to be an objective "tipping point" in terms of deformity progression and might represent an upper limit of acceptable in terms of surgical deformity correction.
... Common causes of hallux rigidus are faulty function (biomechanics) and structural abnormalities of the foot that can ... by cold, damp weather Difficulty with certain activities (running, squatting) Swelling and inflammation around the joint As ...
McBride's operation for hallux valgus can be used in patients older than 30 years
Gebuhr, Peter Henrik; Soelberg, M; Larsen, T
1992-01-01
Over a 10-year period, 46 feet with hallux valgus in 36 patients were treated with the McBride procedure. The median age was 35 years. At follow-up of 2 to 11 years after operation, a reduction in the hallux valgus angles, the intermetatarsal angles and the width of the forefeet was found. In pat...
Tendon shift in hallux valgus: observations at MR imaging
Eustace, S. [Department of Radiology, Boston University Medical Center Hospital, 88 East Newton Street, Atrium - 2, Boston, MA 02118 (United States); Williamson, D. [Department of Radiology, Brigham and Womens Hospital, Boston, Massachusetts (United States); Wilson, M. [Department of Orthopedics, Brigham and Womens Hospital, Boston, Massachusetts (United States); O`Byrne, J. [Department of Radiology, Boston University Medical Center Hospital, 88 East Newton Street, Atrium - 2, Boston, MA 02118 (United States); Bussolari, L. [Department of Radiology, Brigham and Womens Hospital, Boston, Massachusetts (United States); Thomas, M. [Department of Radiology, Brigham and Womens Hospital, Boston, Massachusetts (United States); Stephens, M. [Department of Radiology, Boston University Medical Center Hospital, 88 East Newton Street, Atrium - 2, Boston, MA 02118 (United States); Stack, J. [Department of Radiology, Boston University Medical Center Hospital, 88 East Newton Street, Atrium - 2, Boston, MA 02118 (United States); Weissman, B. [Department of Radiology, Brigham and Womens Hospital, Boston, Massachusetts (United States)
1996-08-01
Objective. This study was undertaken to demonstrate a shift in tendon alignment at the first metatarsophalangeal joint in patients with hallux valgus by means of magnetic resonance imaging. Design. Ten normal feet and 20 feet with the hallux valgus deformity conforming to conventional clinical and radiographic criteria were prospectively studied using magnetic resonance imaging. Correlation was made between tendon position at the first metatarsophalangeal joint and the severity of the hallux valgus deformity. Results. There is a significant shift in tendon position at the first metatarsophalangeal joint of patients with hallux valgus. The insertion of the abductor hallucis tendon is markedly plantarward and the flexor and extensor tendons bowstring at the first metatarsophalangeal joint compared with patients without the deformity. The severity of the tendon shift correlates with the hallux valgus angle and clinical severity of the hallux valgus deformity in each case. Conclusion. Patients with hallux valgus have a significant tendon shift at the first metatarsophalangeal joint which appears to contribute to development of the deformity. (orig.). With 4 figs., 1 tab.
Effects of balance taping using kinesiology tape in a patient with moderate hallux valgus
Lee, Sun-Min; Lee, Jung-Hoon
2016-01-01
Abstract Background: Hallux valgus, an increased angle of lateral deviation in the big toe, can cause pain and difficulties in balancing and walking. This study aimed to investigate the effects of balance taping using elastic therapeutic tape on moderate hallux valgus. Methods: When she walked with shoes, she complained of pain over the medial eminence of the hallux metatarsophalangeal (MTP) joint. Balance taping using kinesiology tape was applied for 3 months (average, 16hours/d) to both big...
Hallux varus following scarf osteotomy.
Akhtar, Shahid; Malek, Sabur; Hariharan, Kartik
2016-12-01
Hallux varus is an uncommon condition and majority of the cases are iatrogenic. It can occur as a result of any type of hallux valgus correction surgery and in our cases scarf osteotomy is not an exception. Treatment of this complication can be challenging and it is important to understand the factors that cause this deformity before embarking on surgical correction. Four cases of hallux varus following Scarf osteotomy (1% of our total Scarf osteotomy cases) and discuss the salient features of these patients. The authors ascertained the factors that caused iatrogenic hallux varus and formulated a classification of the nature of the deformity. The management of iatrogenic hallux varus based on our experience and proposed classification system has also been outlined and discussed. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.
The hallux sesamoids revisited
Potter, H.G.; Pavlov, H. (Cornell Univ. Medical Coll., New York, NY (United States) Hospital for Special Surgery and New York Hospital, NY (United States)); Abrahams, T.G. (Univ. of Vermont School of Medicine and Maine Medical Center, Portland, ME (United States))
1992-10-01
The hallux sesamoids are vulnerable to significant injury and weight-bearing stress in both the athlete and the nonathlete. Unfortunately, they are often dismissed as inconsequential accessory bones. The historical significance, embryology, anatomy, and physiology of the sesamoids and the salient features of both traumatic and nontraumatic pathologic conditions affecting these structures are presented. Because the sesamoids can be responsible for prolonged disabling foot pain and discomfort, it is important for both clinician and radiologist to pay attention to these bones and recognize the early signs of abnormality. (orig.).
Effects of balance taping using kinesiology tape in a patient with moderate hallux valgus
Lee, Sun-Min; Lee, Jung-Hoon
2016-01-01
Abstract Background: Hallux valgus, an increased angle of lateral deviation in the big toe, can cause pain and difficulties in balancing and walking. This study aimed to investigate the effects of balance taping using elastic therapeutic tape on moderate hallux valgus. Methods: When she walked with shoes, she complained of pain over the medial eminence of the hallux metatarsophalangeal (MTP) joint. Balance taping using kinesiology tape was applied for 3 months (average, 16hours/d) to both big toes of a 26-year-old woman with moderate hallux valgus. Results: On the right side, the hallux valgus angle (HVA) decreased from 21° to 14° and the intermetatarsal angle (IMA) decreased from 15° to 14.5°. On the left side, the HVA decreased from 22° to 11° and the IMA decreased from 15° to 12°. Furthermore, the patient was able to walk long distances in shoes without pain in the medial eminence of the hallux metatarsophalangeal joint. Conclusion: This study suggested that repeated balance taping with kinesiology tape could be used as a complementary treatment method for moderate hallux valgus. PMID:27861365
Considering treatment of Hallux Valgus
Llontop Vite, Carlos S.; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú; Temple S., Roberto; Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Perú
2014-01-01
Hallux valgus , common and unsightly foot deformation, apparent simplicity , is to present a complex etiopathogenic and therapeutic problem . The multiplicity of proposed techniques for correction and the diversity of etiological theories , undoubtedly pose a series of controversies uncertain solution . Hallux valgus , as any medical problem should be approached from a global point of view. It is extremely important then assess foot deformities therefore carry often personality disorders and ...
Yadollah Pournia
2012-02-01
Full Text Available Hallux valgus or the lateral deviation of the great toe is a complex disease. If it is not treated, it will cause the deviation of other toes. Hallux valgus is three times more common in females and may cause uncomfortable deformity of the foot, problems in putting on unsuitable and narrow toe box shoes, and pain on the medial side of the first metatarsophalangeal joint; therefore, patients seek medical services. Untreated hallux valgus may cause the hammer toe deformity of the second toe. In this cohort study, 30 patients referring to the Orthopedic Clinic of Shohada Ashayer Hospital of Khorramabad, Iran, with a complaint of hallux valgus were randomly divided into two groups. The splints designed by the researches (slippers splints were given to the case group, and the splints on the market including night splints and interdigital pads were given to the control group. The patients were followed every three months for a year and every time the weight bearing anteroposterior radiography of both feet were taken and hallux valgus and inter-metatarsal angles were measured. The data was analyzed by the SPSS software using repeated measure tests. In the case group that used the designed splints regularly, hallux valgus angles decreased more dramatically than in the control group (P<0.001. This study showed that, despite controversies over the nonoperative treatment of hallux valgus, if hallux valgus angle in patient is mild to moderate, the splint can be used as a nonoperative treatment.
Wester, Jens Ulrik; Hamborg-Petersen, Ellen; Herold, Niels
2016-01-01
BACKGROUND: Different techniques of proximal osteotomies have been introduced to correct severe hallux valgus. The open wedge osteotomy is a newly introduced method for proximal osteotomy. The aim of this prospective randomized study was to compare the radiological and clinical results after...... operation for severe hallux valgus, comparing the open wedge osteotomy to the crescentic osteotomy which is our traditional treatment. METHODS: Forty-five patients with severe hallux valgus (hallux valgus angle >35̊, and intermetatarsal angle >15̊) were included in this study. The treatment was proximal...... open wedge osteotomy and fixation with plate (Hemax), group 1, or operation with proximal crescentic osteotomy and fixation with a 3mm cannulated screw, group 2. The mean age was 52 years (19-71). Forty-one females and four males were included. Clinical and radiological follow-ups were performed 4...
Karpe, Prasad; Killen, Marie C; Pollock, Raymond D; Limaye, Rajiv
2016-12-01
Translation and shortening of Scarf osteotomy allows correction of severe hallux valgus deformity. Shortening may result in transfer metatarsalgia. To evaluate outcome of patients undergoing shortening Scarf osteotomy for severe hallux valgus deformities. Fifteen patients (20feet, mean age 58 years) underwent shortening Scarf osteotomy for severe hallux valgus deformities. Outcomes were pre and postoperative AOFAS scores, IM and HV angles, patient satisfaction. Mean follow-up was 25 months (range 22-30). The IM angle improved from a median of 18.60 (range 13.4-26.20) preoperatively to 9.70 (range 8.0-13.70) postoperatively (8.9; 95% CI=7.6-10.3; posteotomies united. Shortening Scarf osteotomy is a viable option for treating severe hallux valgus deformities with no transfer metatarsalgia. Copyright © 2016 Elsevier Ltd. All rights reserved.
Hallux ulceration in diabetic patients.
ElMakki Ahmed, Mohamed; Tamimi, Abdulhakim O; Mahadi, Seif I; Widatalla, Abubakr H; Shawer, Mohamed A
2010-01-01
We undertook a prospective cohort study to assess risk factors associated with hallux ulceration, and to determine the incidence of healing or amputation, in consecutive patients with diabetes mellitus who were treated over the observation period extending from September 2004 to March 2005, at the Jabir Abu Eliz Diabetic Centre, Khartoum City, Sudan. There were 122 diabetic patients in the cohort (92 males and 30 females) with an overall mean age of 58 +/- 9 years. Fifty-three percent of patients had complete healing within 8 weeks and 43% healed within 20 weeks. The overall mean time to healing was 16 +/- 8 weeks. In 32 (26.2%) patients, osteomyelitic bone was removed, leaving a healed and boneless hallux. The hallux was amputated in 17 (13.9%) patients; in 2 (1.6%) patients it was followed by forefoot amputation and in 7 (5.7%) patients by below-the-knee amputation. In 90 (73.8%) patients the initial lesion was a blister. In conclusion, hallux ulceration is common in patients with diabetes mellitus and is usually preceded by a blister. Neuropathy, foot deformity, and wearing new shoes are common causative factors; and ischemia, osteomyelitis, any form of wound infection, and the size of the ulcer are main outcome determinants. Complete healing occurred in 103 (85%) of diabetic patients with a hallux ulcer. Vascular intervention is important relative to limb salvage when ischemia is the main cause of the ulcer.
Lee, Sun-Min; Lee, Jung-Hoon
2016-11-01
Hallux valgus, an increased angle of lateral deviation in the big toe, can cause pain and difficulties in balancing and walking. This study aimed to investigate the effects of balance taping using elastic therapeutic tape on moderate hallux valgus. When she walked with shoes, she complained of pain over the medial eminence of the hallux metatarsophalangeal (MTP) joint. Balance taping using kinesiology tape was applied for 3 months (average, 16hours/d) to both big toes of a 26-year-old woman with moderate hallux valgus. On the right side, the hallux valgus angle (HVA) decreased from 21° to 14° and the intermetatarsal angle (IMA) decreased from 15° to 14.5°. On the left side, the HVA decreased from 22° to 11° and the IMA decreased from 15° to 12°. Furthermore, the patient was able to walk long distances in shoes without pain in the medial eminence of the hallux metatarsophalangeal joint. This study suggested that repeated balance taping with kinesiology tape could be used as a complementary treatment method for moderate hallux valgus.
Mitchell′s osteotomy in the management of hallux valgus: An Indian perspective
Baba Asif
2009-01-01
Full Text Available Background: Hallux valgus is a common condition that affects the forefoot. A large number of procedures are described for managing this condition. Mitchell′s osteotomy and its modifications are being widely used for treating hallux valgus. However, most of the studies describe the results from the developed world. We present results of the classic Mitchell′s osteotomy in hallux valgus in Indian subcontinent. Materials and Methods: Forty eight adult patients (including 12 bilateral ones in the age range of 18-60 years with hallux valgus were managed with the classic Mitchell′s osteotomy. Pain over the bunion was the reason for surgery in 53 of 60 feet and cosmesis in the remaining 7 feet. Patients with hallux valgus angle more than 20° degrees and not responding to a trial of conservative treatment were included. Patients having metatarsophalangeal (MTP joint osteoarthritis (Grade II and higher, hallux rigidus, rheumatoid arthritis, and with subluxation of MTP joint were excluded from the study. Further, patients with first metatarsal more than 3 mm shorter than second metatarsal were also excluded. Results: The average follow-up period is 3 yrs (range 18months - 6yrs. About 55 feet (83% were painless after surgery. Forty-two (70% patients were happy with the cosmetic results of the surgery. Metatarsalgia was the reason for dissatisfaction with the procedure in five patients. The average correction of hallux valgus and the intermetatarsal angles achieved was 19.7° and 6.9°, respectively. Using the Broughton and Winson scoring system, 37 (61.7% feet had excellent results, 18 (30% had good, and five (8.3% feet had a poor results. Conclusion: The classic Mitchell′s procedure is a simple procedure and gives good cosmetic and radiological results.
McBride's operation for hallux valgus can be used in patients older than 30 years
Gebuhr, Peter Henrik; Soelberg, M; Larsen, T
1992-01-01
Over a 10-year period, 46 feet with hallux valgus in 36 patients were treated with the McBride procedure. The median age was 35 years. At follow-up of 2 to 11 years after operation, a reduction in the hallux valgus angles, the intermetatarsal angles and the width of the forefeet was found....... In patients older than 30 years there were significant reductions. In patients younger than 30 years, the reduction was not significant. The rate of problems with daily footwear was reduced from 36 of 46 feet to 13 of 38 feet. The authors noted few problems and a high rate of satisfied patients, despite...... the age. In 37 of 46 feet the overall result was found satisfactory by the patients. The authors find that McBride's operation can be used for hallux valgus, also in patients above 30 years, in spite of the generally accepted restriction to younger individuals....
A geometric analysis of hallux valgus: correlation with clinical assessment of severity
Vila Joan
2009-05-01
Full Text Available Abstract Background Application of plane geometry to the study of bunion deformity may represent an interesting and novel approach in the research field of hallux valgus. For the purpose of contributing to development of a different perspective in the assessment of hallux valgus, this study was conducted with three objectives: a to determine the position on the intersection point of the perpendicular bisectors of the longitudinal axes of the first metatarsal and proximal phalanx (IP, b to correlate the location of this point with hallux valgus deformity according to angular measurements and according to visual assessment of the severity carried out by three independent observers, and c to assess whether this IP correlated with the radius of the first metatarsophalangeal arc circumference. Methods Measurements evaluated were intermetatarsal angle (IMA, hallux valgus angle (HVA, and proximal phalangeal articular angle (PPAA. The Autocad® program computed the location of the IP inside or outside of the foot. Three independent observers rated the severity of hallux valgus in photographs using a 100-mm visual analogue scale (VAS. Results Measurements of all angles except PPAA showed significantly lower values when the IP was located out of the foot more distantly and vice versa, significantly higher values for severe deformities in which the IP was found inside the foot (p p Conclusion The IP is a useful indicator of hallux valgus deformity because correlated significantly with IMA and HVA measurements, VAS scores obtained by visual inspection of the degree of deformity, and location of the center of the first metatarsophalangeal arc circumference.
Hailin Xu; Kaiji Jin; Zhongguo Fu; Mingtai Ma; Zhongdi Liu; Shuai An; Baoguo Jiang
2015-01-01
Background:There are no unified theories as to the anatomical changes that occur with hallux valgus,we investigated the radiological characteristics and anatomical risk factors for hallux valgus deformity in Chinese adults.Methods:We reviewed 141 patients with hallux valgus (206 feet; 15 males,126 females; mean age,58.5 years).These patients attended Peking University People's Hospital from April 2008 to March 2014.All feet had intact radiological data,obtained using the Centricity RIS/PACS system.We measured hallux valgus angle (HVA),1-2 intermetatarsal angle (IMA),proximal articular set angle (PASA),distal articular set angle,hallux interphalangeal angle,metatarsocuneiform angle,size of the medial eminence of the distal first metatarsal,tibial sesamoid position,and joint congruity of the first metatarsophalangeal joint (MTPJ).Results:We found positive correlations between the HVA and IMA (r =0.279,P ＜ 0.01) and HVA and PASA (r =0.358,P ＜ 0.01),but not for IMA and PASA (P ＞ 0.05).Feet were divided into three groups based on HVA severity.IMA (P ＜ 0.05) and PASA (P ＜ 0.05) in the mild group were significantly lower than that in the moderate and severe groups,with no significant difference determined for IMA or PASA between the moderate and severe groups (P ＞ 0.05).Feet were then grouped based on the shape of the first metatarsal head.Using this grouping,HVA was significant higher in the rounded shape (19.92°) than in a flat shape (17.66°).The size of the medial eminence of the distal first metatarsal was positively correlated with HVA (r =0.185,P ＜ 0.01).The medial eminence in the moderate and severe groups was significantly larger than that in the mild group; moderate and severe groups were not significantly different.Conclusions:PASA enlargement is an adaptive change during early hallux valgus formation,and decompensation leads to subdislocation in the first MTPJ.A rounded first metatarsal head would thus predispose a foot to hallux valgus
The treatment of hallux valgus.
Wülker, Nikolaus; Mittag, Falk
2012-12-01
Hallux valgus is the commonest forefoot deformity, with an estimated prevalence of 23% to 35%. It causes symptoms on the medial edge of the foot, the sole, and the small toes. Non-operative treatment may alleviate symptoms but does not correct the deformity of the big toe. Surgery is indicated if the pain persists. The correct operation must be selected from a wide variety of available techniques. In this article, we selectively review the pertinent literature, including the recommendations of medical societies in Germany and abroad, in the light of our own clinical experience. There have been many clinical trials of various treatments for hallux valgus, but very few of these were randomized, and the case numbers were generally small. Mild deformities are best treated by distal first metatarsal osteotomies, e.g. the Chevron osteotomy. Severe deformities require a soft-tissue procedure at the first metatarsophalangeal joint and a proximal first metatarsal osteotomy. In case of osteoarthritis, and in elderly patients, a resection arthroplasty is preferred; arthrodesis is performed in physically active patients. After correction of hallux valgus, patients can usually bear their full weight on the treated foot while wearing a flat surgical shoe. Proper surgical treatment results in a good or very good outcome in 85% of patients and a satisfactory result in a further 10%. The clinical outcome of present treatments seems to be good in most cases, but large-scale randomized trials are still needed to verify the efficacy of the wide variety of operations and fixation techniques that are currently being offered.
Perez Boal, Eduardo; Becerro de Bengoa Vallejo, Ricardo; Fuentes Rodriguez, Miguel; Lopez Lopez, Daniel
2016-01-01
Background Hallux abducto valgus (HAV) is one of the most common forefoot deformities in adulthood with a variable prevalence but has been reported as high as 48%. The study proposed that HAV development involves a skeletal parameter of the first metatarsal bone and proximal phalanx hallux (PPH) to determine if the length measurements of the metatarsal and PPH can be used to infer adult HAV. Methods All consecutive patients over 21 years of age with HAV by roentgenographic evaluation were included in a cross-sectional study. The control group included patients without HAV. The study included 160 individuals. We identified and assessed the following radiographic measurements to evaluate HAV: the distances from the medial (LDM), central (LDC), and lateral (LDL) aspects of the base to the corresponding regions of the head of the PPH. The difference between the medial and lateral aspect of PPH was also calculated. Results The reliability of the variables measured in 40 radiographic films show perfect reliability ranging from 0.941 to 1 with a small error ranging from 0.762 to 0. Also, there were no systematic errors between the two measurements for any variable (P > 0.05). The LDM PPH showed the highest reliability and lowest error. Conclusion It is more suitable to measure the LDM PPH instead of the LDC PPH when calculating the hallux valgus angle based on our reliability results. When the differences of the medial and lateral PPH are greater, the risk for developing HAV increases. PMID:27861517
Therapeutic Management of the Hallux Rigidus
Anoop Aggarwal
2012-01-01
Full Text Available Background. Hallux rigidus is a chronic, disabling condition of foot characterized by reduced great toe extension. The manual therapy approaches are described theoretically however their practical published evidence has not been analyzed well. Objective. Aim of the present paper was to systematically review the literature available for therapeutic management of the hallux rigidus by identifying and evaluating the randomized controlled trials (RCTs and non-RCTs. Methods. To view the hallux rigidus and its rehabilitation, a webbased published literature search of Pubmed, Ovid Medline, Science direct, Cochrane Database, PEDro database, CINAHL was conducted for last 35 years in August 2010 using 4 specific keywords “hallux rigidus, physical therapy, chiropractic, and manual therapy” typed in exactly same manner in the search column of the databases. Result. the review finds that there is acute need of the quality studies and RCTs for the manual therapy, chiropractic, or physiotherapeutic management of the hallux rigidus. Conclusion. Review conclude that conservative programs for hallux rigidus consists of comprehensive intervention program that includes great toe mobilization, toe flexor strengthening, sesamoid bones mobilization and long MTP joint. The clinician should put an emphasis on the mobilization program with proper follow up along with comparative studies for rehabilitation of hallux rigidus.
Double First Metatarsal and Akin Osteotomy for Severe Hallux Valgus.
Al-Nammari, Shafic Said; Christofi, Theodoros; Clark, Callum
2015-10-01
The technique of double first metatarsal osteotomies was first developed in response to the high frequency of recurrence noted in the treatment of severe adolescent congruent hallux valgus deformities. The concept behind the use of this technique is that it allows the individual correction of each component of the deformity. We have modified the technique for use in adult hallux valgus where the majority of deformities are incongruent deformities and the distal chevron osteotomy is used primarily for its additional translational properties rather than purely to correct the distal metatarsal articular angle (DMAA). We report on a series of double first metatarsal osteotomies (basal opening wedge and distal chevron osteotomy) with Akin osteotomy in the treatment of moderate to severe adult hallux valgus deformity. All patients presenting to our institution with a hallux valgus deformity and treated with this procedure between 2008 and 2013 with a minimum of 1 year of follow-up were identified. Data were obtained through review of case notes, electronic charts, and digital imaging. A total of 50 feet in 48 patients underwent double first metatarsal osteotomy with Akin osteotomy. Three patients were excluded due to loss to follow-up, leaving 47 feet in 45 patients with a mean follow-up of 45 months (range, 14-60 months). Of these 43 (96%) were female and the mean age was 56 years (range, 35-70 years). The mean preoperative hallux valgus angle (HVA), intermetatarsal angle (IMA), DMAA, sesamoid position, and lateral first metatarsotalar angle were 42 degrees (range, 32-52 degrees), 18 degrees (range, 6-26 degrees), 12 degrees (range, 4-26 degrees), stage 6 (range, 4-7), and 2 degrees of dorsiflexion (range, 20 degrees of dorsiflexion to 4 degrees of plantar flexion), respectively. The mean postoperative HVA, IMA, DMAA, sesamoid position, and lateral first metatarsotalar angle were 7 degrees (range, 2 to 24 degrees), 4 degrees (range, 4-14 degrees), 6 degrees (range, 10
Oliver, Noah G; Attinger, Christopher E; Steinberg, John S; Evans, Karen K; Vieweger, David; Kim, Paul J
2015-01-01
Diabetic foot ulceration of the plantar hallux is a challenging condition and can require partial hallux amputation when complicated by infection. Lower extremity biomechanics play an important role in the development of hallux ulcers, and hallux rigidus (HR) could influence the outcomes after partial hallux amputation. We hypothesized that radiographic evidence of HR in patients with diabetes would be associated with greater ulcer recurrence and reamputation rates after partial hallux amputation. We performed a retrospective review of all patients with diabetes who had undergone a partial hallux amputation from January 2005 to December 2012. The subjects were divided into 2 cohorts according to the presence or absence of HR identified on preoperative radiographs. Baseline characteristics and outcomes were compared using a 2-sample Student's t test for continuous variables, and categorical variables were compared using the chi-square test for homogeneity and Fisher's exact test. A total of 52 patients were included, with 16 (31%) positive for radiographic evidence of HR at partial hallux amputation. Differences in the patient demographics and comorbidities were not significant between 2 cohorts with and without HR or reamputation. Reamputation was required in 5 subjects (31%) with HR and 2 (6%) without HR (p = .023). The average follow-up duration was 126 ± 89 weeks. Our results have demonstrated that the reamputation rate after partial hallux amputation is significantly greater in patients with than in those without radiographic evidence of HR. Surgeons should evaluate patients for HR when planning partial hallux amputation and use adjuvant methods of offloading when HR is evident to prevent recurrent ulceration and reamputation. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.
翁习生; 贺仁诚; 李柯; 廉清宇; 李秉璐
1995-01-01
72 feet with hallux valges among 40 patients treated by recoestruction of metatarsal arch and modified McBride operation are reported in this paper. After an average of 4. 5 years of postoperative follow-up , the results showed an overll 9° and 3° correction of the hallux abductes angle and the intermetatarsal angle, re-spectively. 95% of the cases of bunions disappeared, 66% calli under the heads of the first and second metatarsal disappeared, and 91% patients were satisfied with the changes of their feet appearance.
Kilmartin Timothy E
2010-02-01
Full Text Available Abstract Background The Cochrane review of hallux valgus surgery has disputed the scientific validity of hallux valgus research. Scoring systems and surrogate measures such as x-ray angles are commonly reported at just one year post operatively but these are of dubious relevance to the patient. In this study we extended the follow up to a minimum of 8 years and sought to address patient specific concerns with hallux valgus surgery. The long term follow up also allowed a comprehensive review of the complications associated with the combined rotation scarf and Akin osteotomies. Methods Between 1996 and 1999, 101 patients underwent rotation scarf and Akin osteotomies for the treatment of hallux valgus. All patients were contacted and asked to participate in this study. 50 female participants were available allowing review of 73 procedures. The average follow up was over 9 years and the average age at the time of surgery was 57. The participants were physically examined and interviewed. Results Post-operatively, in 86% of the participants there were no footwear restrictions. Stiffness of the first metatarsophalangeal joint was reported in 8% (6 feet; 10% were unhappy with the cosmetic appearance of their feet, 3 feet had hallux varus, and 2 feet had recurrent hallux valgus. There were no foot-related activity restrictions in 92% of the group. Metatarsalgia occurred in 4% (3 feet. 96% were better than before surgery and 88% were completely satisfied with their post-operative result. Hallux varus was the greatest single cause of dissatisfaction. The most common adverse event in the study was internal fixation irritation. Hallux valgus surgery is not without risk and these findings could be useful in the informed consent process. Conclusions When combined the rotation scarf and Akin osteotomies are an effective treatment for hallux valgus that achieves good long-term correction with a low incidence of recurrence, footwear restriction or metatarsalgia
Lew, Eric; Nicolosi, Nicole; McKee, Patrick
2015-01-01
Patients with chronic diabetes can develop plantar hallux ulcerations secondary to neuropathy, increased pressure, and deformity. The present retrospective study evaluated the efficacy of hallux interphalangeal joint (HIPJ) arthroplasty to address recalcitrant ulceration. Two groups of patients with diabetes were compared: a surgical group of 13 patients and a nonsurgical standard therapy group of 13 patients. The patients in the surgical group underwent HIPJ arthroplasty. All the patients in the standard therapy group received local wound care and offloading. The mean duration of follow-up was 19.5 (range 1.2 to 47.9) months, and the mean age was 55 ± 13.0 years. Statistical significance was found in the surgical group for faster time to healing (3.5 weeks [2.5, 4.25] vs 9 weeks [2, 17.29], p = .033) and lower incidence of ulcer recurrence (8% ± 7.69 vs 54% ± 53.85, p = .031). There were also fewer amputations in the surgical group (0% ± 0 vs 38% ± 38.6, p = .063). To our knowledge, only 1 other published study has evaluated HIPJ arthroplasty as a treatment of recalcitrant hallux ulceration. The present study adds comparison data from a nonoperative standard therapy group and found that HIPJ arthroplasty is an effective curative treatment option to address chronic plantar hallux ulcerations in diabetic patients with neuropathy.
Han, Seung Hwan; Park, Eui Hyun; Jo, Joon; Koh, Yong Gon; Lee, Jin Woo; Choi, Woo Jin; Kim, Yong Sang
2015-05-01
The aim of this study was to compare clinical and radiographic outcomes of proximal opening wedge osteotomy using a straight versus oblique osteotomy. We retrospectively reviewed 104 consecutive first metatarsal proximal opening wedge osteotomies performed in 95 patients with hallux valgus deformity. Twenty-six feet were treated using straight metatarsal osteotomy (group A), whereas 78 feet were treated using oblique metatarsal osteotomy (group B). The hallux valgus angle (HVA), intermetatarsal angle (IMA), distal metatarsal articular angle, and distance from the first to the second metatarsal (distance) were measured for radiographic evaluation, whereas the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score was used for clinical evaluation. Significant corrections in the HVA, IMA, and distance from the first to the second metatarsal were obtained in both groups at the last follow-up (posteotomy, an oblique first metatarsal osteotomy yielded better clinical and radiological outcomes.
Wester, Jens Ulrik; Hamborg-Petersen, Ellen; Herold, Niels; Hansen, Palle Bo; Froekjaer, Johnny
2016-03-01
Different techniques of proximal osteotomies have been introduced to correct severe hallux valgus. The open wedge osteotomy is a newly introduced method for proximal osteotomy. The aim of this prospective randomized study was to compare the radiological and clinical results after operation for severe hallux valgus, comparing the open wedge osteotomy to the crescentic osteotomy which is our traditional treatment. Forty-five patients with severe hallux valgus (hallux valgus angle >35̊, and intermetatarsal angle >15̊) were included in this study. The treatment was proximal open wedge osteotomy and fixation with plate (Hemax), group 1, or operation with proximal crescentic osteotomy and fixation with a 3mm cannulated screw, group 2. The mean age was 52 years (19-71). Forty-one females and four males were included. Clinical and radiological follow-ups were performed 4 and 12 months after the operation. In group 1 the hallux valgus angle decreased from 39.0̊ to 24.1̊ after 4 months and 27.9̊ after 12 months. In group 2 the angle decreased from 38.3̊ to 21.4̊ after 4 months and 27.0̊ after 12 months. The intermetatarsal angle in group 1 was 19.0̊ preoperatively, 11.6̊ after 4 months and 12.6̊ after 12 months. In group 2 the mean intermetatarsal angle was 18.9̊ preoperatively, 12.0̊ after 4 months and 12.6̊ after 12 months. The AOFAS score improved from 59.3 to 81.5 in group 1 and from 61.8 to 84.8 in group 2 respectively measured 12 months postoperatively. The relative length of the 1 metatarsal compared to 2 metatarsal bone was 0.88 and 0.87 preoperatively and 0.88 and 0.86 for group 1 and 2 respectively measured after 12 months. Crescentic osteotomy and open wedge osteotomy improve AOFAS score and VAS scores on patients operated with severe hallux valgus. No significant difference was found in the two groups looking at the postoperative improvement of HVA and IMA measured 4 and 12 months postoperatively. The postoperative VAS score and AOFAS score were
Díaz Fernández, R
2015-01-01
To evaluate the clinical and radiological results in the surgical treatment of moderate and severe hallux valgus by performing percutaneous double osteotomy. A retrospective study was conducted on 45 feet of 42 patients diagnosed with moderate-severe hallux valgus, operated on in a single centre and by the same surgeon from May 2009 to March 2013. Two patients were lost to follow-up. Clinical and radiological results were recorded. An improvement from 48.14 ± 4.79 points to 91.28 ± 8.73 points was registered using the American Orthopedic Foot and Ankle Society (AOFAS) scale. A radiological decrease from 16.88 ± 2.01 to 8.18 ± 3.23 was observed in the intermetatarsal angle, and from 40.02 ± 6.50 to 10.51 ± 6.55 in hallux valgus angle. There was one case of hallux varus, one case of non-union, a regional pain syndrome type I, an infection that resolved with antibiotics, and a case of loosening of the osteosynthesis that required an open surgical refixation. Percutaneous distal osteotomy of the first metatarsal when performed as an isolated procedure, show limitations when dealing with cases of moderate and severe hallux valgus. The described technique adds the advantages of minimally invasive surgery by expanding applications to severe deformities. Percutaneous double osteotomy is a reproducible technique for correcting severe deformities, with good clinical and radiological results with a complication rate similar to other techniques with the advantages of shorter surgical times and less soft tissue damage. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.
Lucas y Hernandez, J; Golanó, P; Roshan-Zamir, S; Darcel, V; Chauveaux, D; Laffenêtre, O
2016-03-01
The aim of this study was to report a single surgeon series of consecutive patients with moderate hallux valgus managed with a percutaneous extra-articular reverse-L chevron (PERC) osteotomy. A total of 38 patients underwent 45 procedures. There were 35 women and three men. The mean age of the patients was 48 years (17 to 69). An additional percutaneous Akin osteotomy was performed in 37 feet and percutaneous lateral capsular release was performed in 22 feet. Clinical and radiological assessments included the type of forefoot, range of movement, the American Orthopedic Foot and Ankle (AOFAS) score, a subjective rating and radiological parameters. The mean follow-up was 59.1 months (45.9 to 75.2). No patients were lost to follow-up. The mean AOFAS score increased from 62.5 (30 to 80) pre-operatively to 97.1 (75 to 100) post-operatively. A total of 37 patients (97%) were satisfied. At the last follow up there was a statistically significant decrease in the hallux valgus angle, the intermetatarsal angle and the proximal articular set angle. The range of movement of the first metatarsophalangeal joint improved significantly.. There was more improvement in the range of movement in patients who had fixation of the osteotomy of the proximal phalanx. Preliminary results of this percutaneous approach are promising. This technique is reliable and reproducible. Its main asset is that it maintains an excellent range of movement. The PERC osteotomy procedure is an effective approach for surgical management of moderate hallux valgus which combines the benefits of percutaneous surgery with the versatility of the chevron osteotomy whilst maintaining excellent first MTPJ range of motion. ©2016 The British Editorial Society of Bone & Joint Surgery.
Involvement of valgus hindfoot deformity in hallux valgus deformity in rheumatoid arthritis.
Yamada, Shutaro; Hirao, Makoto; Tsuboi, Hideki; Akita, Shosuke; Matsushita, Masato; Ohshima, Shiro; Saeki, Yukihiko; Hashimoto, Jun
2014-09-01
The involvement of valgus hindfoot deformity in hallux valgus deformity was confirmed in a rheumatoid arthritis case with a destructive valgus hindfoot deformity. Correction of severe valgus, calcaneal lateral offset, and pronated foot deformity instantly normalized hallux valgus deformities postoperatively. Thus, careful hindfoot status evaluation is important when assessing forefoot deformity, including hallux valgus, in rheumatoid arthritis cases.
Foot pain and functional limitation in healthy adults with hallux valgus: a cross-sectional study
Nix Sheree E
2012-10-01
Full Text Available Abstract Background Hallux valgus (HV is a very common deformity of the first metatarsophalangeal joint that often requires surgical correction. However, the association between structural HV deformity and related foot pain and disability is unclear. Furthermore, no previous studies have investigated concerns about appearance and difficulty with footwear in a population with HV not seeking surgical correction. The aim of this cross-sectional study was to investigate foot pain, functional limitation, concern about appearance and difficulty with footwear in otherwise healthy adults with HV compared to controls. Methods Thirty volunteers with HV (radiographic HV angle >15 degrees and 30 matched controls were recruited for this study (50 women, 10 men; mean age 44.4 years, range 20 to 76 years. Differences between groups were examined for self-reported foot pain and disability, satisfaction with appearance, footwear difficulty, and pressure-pain threshold at the first metatarsophalangeal joint. Functional measures included balance tests, walking performance, and hallux muscle strength (abduction and plantarflexion. Mean differences (MD and 95% confidence intervals (CI were calculated. Results All self-report measures showed that HV was associated with higher levels of foot pain and disability and significant concerns about appearance and footwear (p Conclusions These findings show that HV negatively impacts on self-reported foot pain and function, and concerns about foot appearance and footwear in otherwise healthy adults. There was also evidence of impaired hallux muscle strength and increased postural sway in HV subjects compared to controls, although general physical functioning and participation in physical activity were not adversely affected.
Halstead, Jill; Redmond, Anthony C
2006-08-01
Case control study. To explore the validity of the assumptions underpinning the Hubscher maneuver of hallux dorsiflexion in relaxed standing, by comparing the relationship between static and dynamic first metatarsophalangeal (MTP) joint motions in groups differentiated by normal and abnormal clinical test findings. Limitation of motion at the first MTP joint during gait may be due to either structural or functional factors. Functional hallux limitus (FHL) has been proposed as a term to describe the situation in which the first MTP joint shows no limitation when non-weight bearing, but shows limited dorsiflexion during gait. One clinical test of first MTP joint limitation during standing (the Hubscher maneuver or Jack's test) has become widely used in physical therapy, orthopedic, and podiatric assessments, supposedly to assess for the presence of hallux limitations during gait. The utility of the test is based on an assumption that restriction during the static maneuver is predictive of functional limitation at this joint during gait. Despite a lack of evidence for the validity of such an assumption, the outcome of the static test is often used to infer risk of overuse injury or as an outcome for functional therapy. This paper examines the validity of the assumptions supporting this widely used static test. First-MTP-joint motion was assessed using an electromagnetic motion tracking system in cases (n = 15) demonstrating clinically limited passive hallux dorsiflexion in relaxed standing, and in 15 controls matched for age and gender and demonstrating a clinically normal Hubscher maneuver. Maximum hallux dorsiflexion was measured with the subject non-weight bearing (seated), during relaxed standing, and during normal walking. Hallux dorsiflexion was similar in cases and controls when motions were measured non-weight bearing (cases mean +/- SD, 55.0 degrees +/- 11.0 degrees; controls mean + SD, 55.0 degrees +/- 10.7 degrees), confirming the absence of structural
Perisciatic infusion of ropivacaine and analgesia after hallux valgus repair
Zaric, D; Jørgensen, B G; Laigaard, F;
2010-01-01
Moderate to severe pain after hallux valgus repair can be successfully treated with a continuous popliteal sciatic nerve block in ambulatory patients. Different anesthesiologists use various infusion rates for this purpose. The aim of this study was to compare the analgesic efficacy of two infusion...
Osteosarcoma: A rare cause of painful enlargement of the hallux.
Sproule, J A
2011-12-01
Malignant osseous and soft-tissue tumors of the foot are rare. We report a case of osteosarcoma in the proximal phalanx of the hallux in a 45-year-old man. In patients with foot-related symptoms, a high index of suspicion for pedal osteosarcoma is required. Delayed or inappropriate diagnosis may compromise limb-sparing surgery and survivorship.
Takao, Masato; Komatsu, Fumito; Oae, Kazunori; Miyamoto, Wataru; Uchio, Yuji; Ochi, Mitsuo; Matsushita, Takashi
2007-10-01
Flat foot and/or metatarsal primus varus are the major causes of hallux valgus, and it is important to correct these deformities in order to prevent the recurrence of this condition. We demonstrate the clinical and radiological assessment of the correction of hallux valgus, metatarsal primus varus, and flat foot after proximal oblique-domed osteotomy of the metatarsus with distal soft tissue reconstruction. Twenty-seven feet of 22 patients with moderate or severe hallux valgus who had undergone proximal oblique-domed osteotomy were studied. After the adductor hallucis tendon was cut at the attachment of the proximal phalanx and at the sesamoid bone, the osteotomy was performed 3 cm dorsal-distal to the metatarsocuneiform joint to transfer distal fragment approximately 5 mm in the plantar direction, and rotated laterally decreasing the first-second intermetatarsal angle to 5 degrees. The mean AOFAS score was 54.1 +/- 2.8 points at pre-operation and 92.8 +/- 4.8 points at the most recent follow-up (P surgery and at one year after surgery. The average improvement of the talar pitch and calcaneal plantar angle was 2.6 +/- 1.4 and 2.4 +/- 1.5 degrees, respectively. This study suggest that proximal oblique-domed osteotomy of the metatarsal as a surgical procedure for the treatment of moderate or severe hallux valgus with flat foot can be recommended to correct the longitudinal arch of the foot and the first-second intermetatarsal angle.
Vander Griend, Robert
2017-02-01
Operative correction of a symptomatic hallux valgus interphalangeus (HVI) deformity is often achieved with an osteotomy at the proximal end of the proximal phalanx (Akin osteotomy). However, the apex of the typical HVI deformity (center of rotation angle) is at the interphalangeal joint of the hallux. This study was done to evaluate the results of performing a medial closing wedge osteotomy at the distal end of the proximal phalanx. Thirty-three patients (33 feet) underwent an osteotomy at the distal end of the proximal phalanx for correction of HVI. All of the patients had other forefoot deformities which were corrected at the same time. Eight of these were revision procedures of prior forefoot operations. The length of follow-up was determined by the associated procedures with a minimum follow-up of 4 months. The preoperative hallux valgus interphalangeus angle averaged 16 degrees of valgus (range 7-32 degrees) and was corrected to an average of 2 degrees of valgus (range 5 degrees valgus to 5 degrees varus). All of the patients were satisfied with the postoperative appearance and function of the first toe. Because of simultaneous correction of numerous other forefoot problems, it was not possible to specifically isolate or evaluate the effects and benefits of this osteotomy using outcomes measures. There was one intraoperative complication resulting in a fracture extending into the adjacent IP joint. Correction of an HVI deformity can be achieved with an osteotomy at the distal end of the proximal phalanx. This was a safe technique with few complications and with good results in terms of both correction and patient satisfaction. Level IV, retrospective case series.
Eustace, S. (Dept. of Radiology, Mater Misericordiae Hospital, Dublin (Ireland)); O' Byrne, J. (Dept. of Orthopaedics, Mater Misericordiae Hospital, Dublin (Ireland)); Stack, J. (Dept. of Radiology, Mater Misericordiae Hospital, Dublin (Ireland)); Stephens, M.M. (Dept. of Orthopaedics, Mater Misericordiae Hospital, Dublin (Ireland))
1993-04-01
This study describes a method of detecting first metatarsal pronation on the basis of the movement of the inferior tuberosity of the base of 20 cadaveric first metatarsals at 0 , 10 , 20 and 30 pronation. On pronation, the inferior tuberosity of the base of the first metatarsal moved lateral to the mid-line axis. At 10 , the tuberosity pointed to the junction of the inner third and outer two-thirds of a line between the midpoint and lateral tubercle of the base. At 20 , it pointed to the junction of the inner two-thirds and outer third of that line. At 30 , it pointed to the outer marting of the lateral third. Using these features, the amount of first metatarsal pronation in 100 consecutive weigth-bearing views of feet was recorded and plotted against the corresponding intermetatarsal angles in those feet. Four of 43 patients with an intermetatarsal angle of less than 9 had pronation greater than 10 , 48 of 57 patients with an intermetatarsal angle greater than 9 had pronation greater than 10 (P<0.001). As intermetatarsal angles increase, the amount of first metatarsal pronation increases (r=0.69). Pronation and varus deviation of the first metatarsal are linked; both alter the tendon balance maintaining proximal phalanx alignment and lead to the development of hallux valgus. (orig.)
Hadi Mohammed
2012-06-01
Conclusion: This study has demonstrated an increased pressure transmitted through the outer aspect of the sole of the foot in the patients suffering from hallux rigidus. This is helpful in choosing treatment options and managing hallux rigidus patients particularly when using conservative and foot wear considerations.
Hallux Rigidus Grade Does Not Correlate With Foot and Ankle Ability Measure Score.
Nixon, Devon C; Lorbeer, Karly F; McCormick, Jeremy J; Klein, Sandra E; Johnson, Jeffrey E
2017-09-01
Classification systems for hallux rigidus imply that, as radiographic changes progress, symptoms will concurrently increase in severity. However, symptom intensity and radiographic severity can be discordant for many patients. We studied the correlation between hallux rigidus grades and the Foot and Ankle Ability Measure (FAAM) scores to better understand this relationship. We retrospectively reviewed weight-bearing radiographs of the foot and FAAM Activities of Daily Living (ADL) questionnaires for 84 patients with hallux rigidus. The Spearman rank coefficient was used to correlate clinical-radiographic hallux rigidus grade with FAAM ADL scores. In 84 patients, the clinical-radiographic grade for hallux rigidus showed no relationship with FAAM ADL score (r = -0.10; P = 0.36) but did show moderate correlation with patient age (r = 0.63; P < 0.001). Advancing radiographic changes in hallux rigidus did not correspond with patient symptoms as measured via FAAM ADL scores. The reliability and validity of current grading criteria for hallux rigidus may require further exploration. Level III.
Joint Manipulation Under Anesthesia for Arthrofibrosis After Hallux Valgus Surgery.
Feuerstein, Catherine; Weil, Lowell; Weil, Lowell Scott; Klein, Erin E; Argerakis, Nicholas; Fleischer, Adam E
2016-01-01
Arthrofibrosis is a known complication of hallux valgus surgery. Joint manipulation under anesthesia has been studied for adhesive capsulitis of the shoulder; however, a paucity of published data exists on the use of this modality in the foot and ankle. The purpose of the present study was to investigate the outcomes of first metatarsophalangeal joint manipulation for arthrofibrosis that occurred as a complication of bunion surgery. The study population consisted of patients attending a single foot and ankle specialty clinic who were evaluated for arthrofibrosis after bunion surgery. Patients who underwent joint manipulation under anesthesia were asked to complete a research visit in which a clinical examination was performed and the presence and severity of joint pain were assessed. A total of 38 patients (34 females, 4 males, 53 feet), with a mean age of 55.7 ± 11.8 (range 30 to 83) years, agreed to participate. The mean follow-up period was 6.5 ± 3.4 (range 1 to 17) years. The visual analog scale scores improved significantly from baseline to the final follow-up visit (baseline 6.5 ± 1.5, range 2 to 10; final follow-up visit 2.3 ± 1.5, range 0 to 6; p arthrofibrosis after surgical correction of hallux valgus. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.
A new and simplified functional tendon transfer for a dropped hallux
Singh Sukhbir
2010-01-01
Full Text Available A case of fracture of the right tibia proximal 1/3rd extending up to diaphysis after a road traffic accident along with a dropped hallux is being reported. The extensor digitorum longus (EDL was intact. Patient was taken up for surgery for the fracture tibia with conservative management for his dropped hallux for initial six weeks. After six weeks when no improvement was seen surgical intervention was planned for the dropped hallux. The subsequent management of this patient is being described.
Boffeli, Troy J; Hyllengren, Shelby B
2015-01-01
Diabetes-related neuropathic ulcers located at the plantar aspect of the hallux interphalangeal joint are often chronic or recurrent and frequently become complicated by osteomyelitis. Once infected, treatment will typically involve hallux amputation. Although intended as a definitive procedure, amputation of the first toe is not desirable from a cosmetic or functional standpoint and often leads to transfer ulcers at adjacent locations of the foot. Reconstructive wound surgery, combined with limited bone resection, is possible if the infection is caught early before the local tissue and bone have become necrotic. In addition to neuropathy, biomechanical issues, including ankle equinus, hallux limitus, hallux extensus, and hallux valgus, predispose patients with diabetes mellitus to developing plantar hallux ulcers. We commonly employ a proximal based unilobed plantar rotational flap combined with hallux interphalangeal joint arthroplasty as an alternative to hallux amputation. We present a typical case with long-term follow-up to highlight our flap protocol, including patient selection criteria, flap design, surgical technique, bone resection and biopsy pearls, staging timeline, and a typical postoperative course. Periodic follow-up during the next 72 months for unrelated conditions allowed long-term monitoring with no recurrence of osteomyelitis or subsequent amputation. The foot remained ulcer free 6 years later. The benefits of this surgical approach include complete excision of the ulcer, adequate exposure for bone resection, early bone biopsy before the spread of infection or necrosis of local tissue, flap coverage with viable soft tissue, and partial offloading of mechanical pressure at the plantar interphalangeal joint.
Neuropathic foot ulcer prevention in diabetic American Indians with hallux limitus.
Dannels, E
1989-09-01
Infected neuropathic ulcerations are the leading cause of diabetes-related partial foot amputations at the Phoenix Indian Medical Center. Ten hallucal ulcerations in seven American Indian patients with hallux limitus were resolved by local wound care and partial first metatarsophalangeal joint resection. The average length of postsurgical follow-up care was 28.8 months. There have been no recurrences of the plantar hallux ulcerations in any of the patients.
Varus instability of the hallux interphalangeal joint in a taekwondo athlete
Gong, Hyun Sik; Kim, Yeun Ho; Park, Moon Seok
2009-01-01
The hallux interphalangeal joint is stable in the transverse plane and there have been only a few reports of varus instability of this joint. A case is described of varus subluxation of the hallux interphalangeal joint in a taekwondo athlete and the surgical outcome after reconstruction of the collateral ligament. Taekwondo athletes, who require fast powerful kicks, should be warned about this type of forefoot injury. PMID:21686680
Giant cell reparative granuloma of the hallux following enchondroma
Kamoun, Khaled; Sellami, Tarak; Jlailia, Zied; Abid, Layla; Jenzri, Mourad; Bouaziz, Mouna; Zouar, Omar
2015-01-01
Giant cell reparative granuloma (GCRG) is a rare, benign intra osseous lytic lesion occurring especially in gnathis bone but also seen in feet and hands. It has similar clinical and radiological presentations than giant cell tumor, chondroblastoma, aneurysmal bone cyst, and hyperparathyroidism brown tumors but with specific histological findings We report a case of a GCRG of hallux phalanx in 18 years old patient appearing many years after enchondroma curettage and grafting. Radiographs showed a multiloculated osteolytic lesions involving whole phalanx with cortical thinning and without fluid-fluid levels in CT view. Expected to be an enchondroma recurrence, second biopsy confirmed diagnosis of GCRG with specific histological findings. Although if aetiopathogeny remains unknown, GCRG is reported to be a local non neoplasic reaction to an intraosseous hemorrhage. Our exceptional case claims that this tumor can appear in reaction to cellular disturbance primary or secondary. PMID:26985281
Disorders of the hallux sesamoid complex: MR features
Karasick, D.; Schweitzer, M.E. [Thomas Jefferson Univ., Philadelphia, PA (United States). Dept. of Radiology
1998-08-01
Numerous painful conditions can affect the first metatarsophalangeal-sesamoid joint complex. Symptoms can be of sudden or insidious onset, and be of acute or chronic duration. Although conventional radiography is recognized as the initial diagnostic procedure for these symptoms, there is often a need to proceed to MR imaging. MR imaging is sensitive and can be utilized in the investigation of the hallux sesamoid complex to differentiate soft tissue from osseous pathology. Synovitis, tendonitis, and bursitis can be distinguished from bony abnormalities such as sesamoid fracture, avascular necrosis, and osteomyelitis. An understanding of MR imaging features and techniques will result in the highest diagnostic yield. Early and accurate diagnosis of sesamoid complex disorders can guide the physician to the appropriate clinical management and prevent potentially harmful longstanding joint dysfunction. (orig.) With 11 figs., 30 refs.
Radiologic Patterning of Hallux Deformity in Rheumatoid Arthritis and Its Relationship to Flatfoot.
Matsumoto, Takumi; Nakada, Izumi; Juji, Takuo; Nakamura, Ichiro; Ito, Katsumi
2016-01-01
Hallux deformities other than hallux valgus, especially those in the sagittal plane, have not yet been elucidated in the feet of patients with rheumatoid arthritis. The objectives of the present study were to classify rheumatoid arthritis hallux deformity in both the horizontal and the sagittal planes and investigate its relationship with flatfoot. Using a cross-sectional study design, we assessed patients with rheumatoid arthritis (527 feet in 274 patients) using radiographs and classified the deformity patterns of the great toes using cluster analysis. Of the 274 patients, the range of motion in the metatarsophalangeal joint was clinically investigated in 44 (16.1%) patients. The great toes could be divided into 5 clusters according to the characteristic configuration as follows: cluster I (normal type), cluster II (hallux valgus type), cluster III (boutonniere type), cluster IV (boutonniere with hallux valgus type), and cluster V (swan-neck type). Radiographic measurements revealed the characteristic deformities of each cluster, including splayed foot for cluster II; flat foot, metatarsal primus elevatus, and plantar displacement of the proximal phalanx for cluster III; and a mixture of these characteristics for cluster IV. Plantar displacement of the proximal phalanx, which was a specific characteristic of the boutonniere deformity, correlated significantly with the decreased dorsiflexion in the metatarsophalangeal joint. Our classification method revealed the relationship of hallux deformity in the sagittal plane to flatfoot and also demonstrated the usefulness of measuring basal phalanx displacement in predicting the range of motion of the metatarsophalangeal joint.
Hallux valgus-a case for a physiotherapist or only for a surgeon? Literature review.
Mortka, Kamila; Lisiński, Przemysław
2015-10-01
[Purpose] Hallux valgus is one of the most common deformations of the human foot, and it causes great difficulties for the patients. The aim of this paper was to review available medical literature in search of evidence which would justify implementation of physiotherapy, based on its effectiveness for patients with hallux valgus. [Subjects and Methods] The following databases were searched for applicable papers: PubMed, Google Scholar, Clinical Key and UpToDate. Full-text articles from the last 15 years were subjected to a review, which ultimately selected seven papers about hallux valgus therapy published over the past 12 years. These studies were grouped according to their design and level of evidence and classified depending on whether they concerned physiotherapy as postoperative therapy or as the only treatment. [Results] The studies included in the present analysis used the following interventions for patients with hallux valgus: exercise, manual therapy, gait training, taping and orthosis. All the studies showed beneficial effects and the most frequently observed results were reductions in pain and improvements in function. [Conclusion] The evidence found in the reviewed materials clearly indicates that patients with hallux valgus should not only be subject to surgical procedures but also undergo physiotherapeutic treatment.
Deenik, A.; Mameren, H van; Visser, E. de; Waal Malefijt, M.C. de; Draijer, F.; Bie, R. de
2008-01-01
BACKGROUND: Chevron osteotomy is a widely accepted osteotomy for correction of hallux valgus.(18) Algorithms were developed to overcome the limitations of distal osteotomies. Scarf osteotomy has become popular as a versatile procedure that should be able to correct most cases of acquired hallux valg
Cho, Jaeho
2014-01-01
Chronic varus instability of the hallux interphalangeal joint is a rare injury, and only a few reports of this injury have been published. In some studies, this injury has been related to taekwondo. Taekwondo is an essential martial art in the Korean military. We have described a case of varus instability of the hallux interphalangeal joint in a professional soldier who had practiced taekwondo for 5 years and the surgical outcome after reconstruction of the lateral collateral ligament with the fourth toe extensor tendon.
Hallux amputation after a freshwater stingray injury in the Brazilian Amazon.
Monteiro, Wuelton Marcelo; Oliveira, Sâmella Silva de; Sachett, Jacqueline de Almeida Gonçalves; Silva, Iran Mendonça da; Ferreira, Luiz Carlos de Lima; Lacerda, Marcus Vinícius Guimarães
2016-01-01
Freshwater stingray injuries are a common problem in the Brazilian Amazon, affecting mostly riverine and indigenous populations. These injuries cause severe local and regional pain, swelling and erythema, as well as complications, such as local necrosis and bacterial infection. Herein, we report a case of bacterial infection and hallux necrosis, after a freshwater stingray injury in the Brazilian Amazon, which eventually required amputation. Different antimicrobial regimens were administered at different stages of the disease; however, avoiding amputation through effective treatment was not achieved.
Congenital tibial dysplasia with lateral bowing and duplication of hallux: case presentations.
Beck, Jennifer J; Altiok, Haluk
2013-05-01
This article reports on two children with congenital unilateral tibial dysplasia with lateral bowing with no associated sagittal plane deformity. In both cases, it is associated with ipsilateral duplication of the hallux. Long-term follow-up of the patients showed spontaneous, almost complete resolution of the bowing without progressing into fracture or pseudoarthrosis. Leg length discrepancy appeared to be the only orthopedic sequela related to this phenomenon.
Scarf截骨治疗(足母)外翻的短期疗效分析%Short-term curative effect of Scarf osteotomy for treatment of hallux valgus
宋秀锋; 李荣俊; 杨涛; 李宏志; 郑加法
2012-01-01
Background: Hallux valgus is a common disease in foot and ankle surgery. It is given priority to the surgical treatment at present. However, there are great differences in terms of clinical outcomes and recurrence for operative treatments. Objective: The purpose of the study is to evaluate the short-term results of Scarf osteotomy combined with other surgical procedures in the treatment of moderate or severe hallux valgus. Methods: From July 2008 to June 2010, 33 patients (41 feet) with moderate or severe hallux valgus were treated with Scarf osteotomy. There were 4 males (4 feet) and 29 females (37 feet) with an average age of 5L7 years (range, 24 to 69 years). The therapeutic effects were assessed by American Orthopedic Foot and Ankle Society (AOFAS) Maryland scoring, X-ray films were taken under enough weight loading during follow-up. Hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured before and after the treatment. Results: The average follow-up time was 20.4 months (range, 12 to 36 months). The mean HVA decreased from 32.78° to 10.18°, and the mean IMA decreased from 11.57° to 6.26°. According to AOFAS Maryland scoring, 28 feet (68.3%) were excellent, 11 feet (26.8%) good, 2 feet (4.9%) fair, and the rate of excellent or good was 95.1 % (39/41). Conclusions: Scarf osteotomy is a reliable method to treat hallux valgus. The osteotomy technique is simple, and could provide satisfactory short-term results with lower complication rate.%背景:(足母)外翻为足踝外科常见病、多发病,目前以各种手术治疗为主,术后效果及复发率有较大差异.目的:探讨Scarf截骨联合其他手术方式治疗中、重度(足母)外翻的短期疗效.方法:2008年7月至2010年6月,采用Scarf截骨治疗中、重度(足母)外翻患者33例(41足),男4例(4足),女29例(37足)；年龄24～69岁,平均51.7岁.在Scarf截骨的基础上部分患者联合第一跖趾关节骨赘切除、软组织松解及(足母)趾近节趾
Klaue, K
1991-12-01
Today, bunion surgery is still very controversial. Considering that a bunion deformity is actually a result of multiple possible causes, the rationale of the currently applied techniques has not been conclusively demonstrated. Multiple techniques are still applied with uncertain outcome, as shown by the not insignificant recurrence rate. The tarsometatarsal reorientation arthrodesis addresses the deficient anteromedial buttress which is due to the most often concomittent hypermobile first ray. This is an important aspect of treating hallux valgus deformity and includes the sagittal alignment besides the horizontal reposition of the metatarsal over the sesamoid complex. Since in hallux valgus, the first metatarsal looses its position also by the insufficiency of the intrinsic musculature and the ligamento-capsular structures, the arthrodesis regulates the elasticity of the multiarticular first ray within the sagittal plane. Recurrences are less likely after this operation, even when performed on the adolescent hallux which is known as very difficult to be treated successfully.
Kia, Cameron; Yoshida, Ryu; Cote, Mark; DiVenere, Jessica; Geaney, Lauren E
2017-04-01
Proximal opening wedge osteotomy (POWO) is an established procedure for moderate to severe hallux valgus. A common concern of this procedure is that it results in lengthening of the first metatarsal, which could cause increased intra-articular pressure of the first metatarsophalangeal joint (MTP) and may ultimately lead to arthritis because of these altered mechanics. The purpose of this study was to use a cadaveric model to compare intra-articular pressures and articulating contact properties of the MTP joint following either scarf osteotomy or POWO. Fresh-frozen cadaveric below-knee specimens with pre-existing hallux valgus (n = 12) and specimens without hallux valgus (n = 6, control group) were used. The hallux valgus specimens were stratified into 2 groups (n = 6 each): POWO or scarf osteotomy. The groups were matched based on the degree of deformity. Peak intra-articular pressure, force, and area were measured in all normal, preoperative, and postoperative specimens with a simulated weightbearing model. These measurements were made with a pressure transducer placed within the first MTP joint. Postoperatively POWO group had slightly higher contact forces and pressures compared to the scarf group and lower contact forces and pressures than those of the normal group but were not statistically significant ( P > .05). Normal specimens had higher intra-articular force, pressure, and area than postoperative specimens but the difference was not found to be significant. First metatarsal lengthening was found in both the scarf and POWO specimens; however, neither increase was found to be significant ( P > .05). The results from this study show that after operative correction, contact properties of the fist MTP joint among normal, POWO, and scarf osteotomy groups revealed no significant differences. First MTP joints in those with hallux valgus had significantly lower contact force and pressure compared to those without hallux valgus. With little long-term outcomes of
Osterwalder, A; Maestretti, G
1993-09-01
The procedure known as the Metatarsus Primus Double Osteotomy ("L'ostéotomie métatarsienne bipolaire" of Schnepp-Carret) for the treatment of the hallux valgus is a logical, efficient and non-mutilating procedure. The technique consists in reducing the hallux valgus deformity by a subcapital bone wedge resection of the metatarsus primus. The bone wedge is then pinched into a second proximal osteotomy of the metatarsus primus, correcting the varus deformity in a valgus direction. This procedure is little known and is not even mentioned in the classic orthopedic literature of German and English language.
Surgical treatment of hallux valgus%(足母)外翻的手术治疗
盛锟琨; 王宸
2009-01-01
Hallux valgus is a frequent forefoot disease, which has the high incidence, more happened among females, hallux valgus becomes more serious along with the age increasing, it usually needed to be done with surgery treatment owing to deformity and pain. The surgery with regard to hallux valgus had emerged widespread at the end of the 18~(th) century, most of the operation styles had been eliminated due to their disadvantages along with the carried out and the follow up judgment of the operation styles , however, some operation styles had been certified effective, which have been modified and consummated endlessly, have been added in the contemporary therapeutic methods. Operation styles mostly consist of soft issue repairment, osteotomy, arthroplasty and arthrodesis , selecting the operation styles reasonably is the key point of guarantee the treatment effectiveness.%(足母)外翻是一种常见的前足疾病,发病率较高,多见于女性,常随年龄增长而呈加重趋势,由于畸形和疼痛,常需手术治疗.(足母)外翻的手术治疗早在18世纪末已广泛兴起,随着各种术式的广泛开展及对其效果的追踪评价,大多数手术方式由于弊大于利被淘汰,而一些术式被证实有效,且经过不断改良与完善,已融入现代治疗方法中,手术方式主要包括软组织修复手术、截骨术、关节成形术及关节融合术,手术方法的合理选择是保证治疗效果的关键.
Traumatic Mallet Toe of the Hallux in a Paediatric Patient: A Case Report
Jason Chow
2013-06-01
Full Text Available We describe a case of traumatic avulsion fracture of the distal phalanx of the hallux in a paediatric patient. The patient had a Salter Harris type III fracture of the distal phalanx with 40% of the articular cartilage involved and a clinical extension lag. We treated the injury non-operatively with applying a fibreglass dorsiflexion interphalangeal plaster for 6 weeks. An excellent outcome was achieved with normal range of interphalangeal motion and solid painless union of fracture at 12 weeks.
Hallux amputation after a freshwater stingray injury in the Brazilian Amazon
Wuelton Marcelo Monteiro
2016-06-01
Full Text Available Abstract: Freshwater stingray injuries are a common problem in the Brazilian Amazon, affecting mostly riverine and indigenous populations. These injuries cause severe local and regional pain, swelling and erythema, as well as complications, such as local necrosis and bacterial infection. Herein, we report a case of bacterial infection and hallux necrosis, after a freshwater stingray injury in the Brazilian Amazon, which eventually required amputation. Different antimicrobial regimens were administered at different stages of the disease; however, avoiding amputation through effective treatment was not achieved.
Correlation between generalized joint hypermobility and hallux valgus
A. A. Kardanov
2015-01-01
Full Text Available Purpose: to evaluate correlation between generalized joint hypermobility, forefoot deformities and elasticity of the first ray of the foot. Material and methods. We examined 138 patients with complaints related with deformities at the forefoot level. During this study the medical history was obtained, the elasticity type of the feet was defined and the degree of motion of the medial metatarsal-cuneiform joint was evaluated. Forefoot elasticity was identified by bringing together the heads I and V metatarsal bones with fingers. If convergence occurred with little resistance, those feet were called hyperelastic. The convergence of the heads I and V metatarsal bones of the foot with an average type of elasticity occurred with resistance. It was impossible to converge the heads of I and V metatarsal bones. Due to the results of weight-bearing and non-weight bearing X-ray, analysis of the main radiographic angles of the foot was performed: between I and V metatarsal bones, between the first and second metatarsal bones and between the first metatarsal bone and proximal phalanx of the great toe. Calculation formula of the forefoot flatness index, showing the average ratios of basic radiographic angles of the foot on the x-ray images (weight-bearing and non-weight bearing was created. An assessment of total joint hypermobility using Beighton scale and evaluation of first ray deformity using DuPont scale were performed. Statistical analysis of obtained data was performed, as a result of which significantly strong correlation between total joint hypermobility, forefoot elasticity and valgus deviation of the great toe were revealed. Results. 11% of the feet were hyperelastic. Calculation of the index of forefoot flatness showed that forefoot flatness wasn’t significant for a rigid foot - 5.6 %, for the feet with an average degree of mobility it was 6.0% and it was expressed for hypemobile feet - 12.3 %. Strong correlation relation between the forefeet
Short term effect of Scarf osteotomy on moderate to severe hallux valgus%Scarf截骨治疗中重度外翻的短期疗效分析
徐子涵; 孙天胜; 汤宇; 戴鹤玲; 刘志杰; 程明
2013-01-01
背景：外翻是最常见的前足畸形，越来越受到矫形外科医生的重视，其治疗方式多种多样，如何选择适合的手术方式是治疗成功的关键。 目的：探讨Scarf截骨术治疗外翻的疗效。 方法：2010年7月至2012年6月，我院采用Scarf截骨术治疗中重度外翻患者47例（61足），男5例（7足），女42例（54足）；年龄20~78岁，平均52.2岁。比较手术前后外翻角及第1、2跖骨间角纠正程度。采用AOFAS评分评估患者临床症状改善情况。 结果：所有患者均获得随访，随访时间4~8个月，平均6个月。外翻角由术前42.6°减小至12.9°，平均减小29.7°。第1、2跖骨间角由术前18.4°减小至8.9°，平均减小9.5°。AOFAS评分由术前49.9分增加至术后86.2分，平均增加26.5分。并发症发生率10%。 结论：Scarf截骨术治疗中重度外翻可以获得较好的短期临床结果，但需严格掌握手术适应证。%Background:Hallux valgus is the most common deformity in forefoot. There are many treatments for it. Therefore, it is very important to choose an appropriate surgical therapy for each patient. Objective:The purpose of the study is to explore the efficacy of Scarf osteotomy for the treatment of hallux valgus. Methods:From July 2010 to June 2012, 47 patients with 61 feet underwent Scarf osteotomy for the treatment of moderate to severe hallux valgus. There were 5 males (7 feet) and 42 females (54 feet) with an average age of 52.2 years (range, 20-78 years). The hallux valgus angle(HVA) and intermetatarsal angle (IMA) were compared before and after surgery. Clinical outcomes were assess by American Orthopedic Foot and Ankle Society (AOFAS) scoring. Results:The mean duration of follow-up was 6 months in all the patients (range, 4-8 months). HVA was decreased by 29.7° (from 42.6° preoperative to 12.9° postoperative). IMA was decreased by 9.5° (from 18.4° preoperative to 8.9° postopera
Isolated intraosseous gout in hallux sesamoid mimicking a bone tumor in a teenaged patient
Liu, Shi-Zuo; Yeh, LeeRen; Chen, Clement Kuen-Huang; Pan, Huay-Ban [Department of Radiology, Kaohsiung Veterans General Hospital, 386 Ta-Chung first Rd., 813, Kaohsiung, Taiwan (Taiwan); Chou, Yi-Jiun [Department of Orthopedics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan (Taiwan)
2003-11-01
We are reporting an unusual case of isolated intraosseous tophus in medial hallux sesamoid presenting as tumor-like lesion in a teenage patient without prior history of gouty attack and underlying systemic disorders. The lesion manifested isointensity to surrounding muscles with internal low signal on spin echo (SE) T1-weighted images, and heterogeneous low signal intensity on fast spin echo (FSE) T2-weighted images. Computed tomography (CT) scan disclosed expansion and diffusely increased attenuation of the medial hallux sesamoid with focal cortical erosion and extraosseous extension of high attenuation content. The subsequent resection and pathology revealed intraosseous tophus deposition, which is particularly rare at this site and at this age. Imaging studies revealed some characteristic imaging features which can retrospectively be attributed to gouty tophus. When an expansile osteolytic lesion manifesting low signal intensity on T2-weighted image and internal calcifications on CT scan is encountered, the possibility of intraosseous tophus should be included in the list of differential diagnoses, even in a teenage patient without prior history of gout. (orig.)
Scarf截骨治疗中重度(足母)外翻%Scarf osteotomy for moderate to severe hallux valgus
宋秀锋; 郑加法; 李宏志; 周锦明; 关盛溢; 赵鹏
2015-01-01
目的 探讨Scarf截骨治疗中重度(足母)外翻的手术技巧及疗效.方法 2008年9月至2014年4月,采用Scarf截骨结合其他手术方法治疗中重度(足母)外翻患者144例(195足),获得随访110例(168足),男12例(16足),女98例(152足);年龄19～71岁,平均51岁.所有病例均采用scarf截骨联合第1跖趾关节骨赘切除、软组织松解手术,多数患者加用(足母)趾近节趾骨Akin截骨.采用美国足踝外科协会(American Orthopedic Foot and Ankle Society,AOFAS)Maryland(足母)跖趾关节评分系统进行疗效评估.术前、术后数据采用SPSS17.0软件进行统计学分析.结果 随访时间12～36个月,平均20.4个月.(足母)外翻角(hallux valgus angle,HVA)较术前平均矫正24.6°,第1、2跖骨间角(intermetatarsal angle,IMA)较术前平均矫正8.4°.AOFAS评分从术前(46.2±13.6)分改善为(86.1±4.1)分.结论 Scarf截骨术具有较好的自身稳定性,可以缩短、延长、旋转和降低第1跖骨头,矫形能力强,接触面积大,愈合快,螺钉内固定可使患者早期下地活动,并发症少,节约医疗费用等优点,结合其他手术方式是治疗中重度(足母)外翻的理想方法.
Effects of the lapidus arthrodesis and chevron bunionectomy on plantar forefoot pressures.
King, Christy M; Hamilton, Graham A; Ford, Lawrence A
2014-01-01
Hallux valgus with or without first ray insufficiency has been strongly implicated as a contributing factor in lesser metatarsal overload. The principle goals of a bunionectomy are to relieve the pain, correct the deformity, and restore first metatarsophalangeal joint congruity. Until now, little evidence has been available to assess the effects of bunionectomy procedures on forefoot pressure. The primary aim of the present prospective study was to evaluate the preoperative and postoperative plantar pressures after 2 specific bunionectomies: the chevron bunionectomy and Lapidus arthrodesis. A total of 68 subjects, 34 in each group, were included for radiographic and pedographic evaluation. Both procedures demonstrated radiographic improvements in the mean intermetatarsal and hallux abductus angles. The mean hallux plantar pressure decreased significantly in both procedure groups (p forefoot pressure (p = .01). Furthermore, the pressure under the second metatarsal as a percentage of the total forefoot pressure decreased significantly (p = .01). This study suggests that the Lapidus arthrodesis and chevron bunionectomy both provide correction for hallux valgus deformity, but when comparing forefoot load sharing pressures, the Lapidus arthrodesis appeared to have greater influence on the load sharing distribution of forefoot pressure than did the bunionectomy employing the chevron osteotomy.
赵鸿声; 靖光武; 张建军; 黄吉利
2012-01-01
目的 探讨跖趾关节内侧副韧带重建加跖趾关节成形术治疗外翻疗效.方法 采用改良跖趾关节成形术治疗外翻23例(38足),并对趾畸形的矫正程度、疼痛症状的改善及行走功能的恢复等进行充分评估.结果 本组患者外翻角(HAV)及第一、二跖骨间夹角(IMA)术前、后比较,差异有统计学意义(P<0.05).术后随访(13.6±2.3)个月,疗效优28足,良8足,可1足,差1足,总优良率达94.7%.结论 跖趾关节内侧副韧带重建加跖趾关节成形术能够治疗多种中、重度外翻及合并趾跖关节炎患者,能有效改善足部外形及症状,恢复行走功能,并发症少.%Objective To investigate clinical effect of medial collateral ligament reconstruction and arthroplasty of metatarsophalangeal joint for the treatment of hallux valgus. Methods From 2006 to 2011,38 feet of 23 patients were treated with the modified operation. All patients were followed up and the degree of deformity correction, the improvement of pain and the recovery of walking function were fully e-valuated. Results After the surgery, there were significant differences in hallux valgus angle( HVA )and intermetatarsal angle( IMA )( P <0. 05 ). All the cases were followed up for( 13. 6 ± 2. 3 )months and an excellent outcome was found in 28 feet, good in 8, fair in 1 and poor in 1, the excellent and good rate was 94.7%. Conclusion The modified metatarsophalangeal joint arthroplasty is an effective method for patients with hallux valgus and extensor digitorum communis arthritis. It can markedly improve the appearance, release the symptoms, restore the function and reduce the complications.
Calvo de Cos, Alberto
2005-01-01
INTRODUCCIÓN La limitación en el plano sagital del movimiento y el dolor de la primera articulación metatarsofalángica fue denominada por primera vez "hallux flexus" en 1887 por Davies-Colley. En 1888 Cotterill fue el primero en utilizar el término "hallux rigidus" para describir esta patología. Después del hallux valgus, el hallux rigidus es la patología que más frecuentemente afecta a la primera articulación metatarsofalángica, pudiendo ser más imposibilitante para el paciente.Después ...
Shahid, Muhammad Saleem; Lee, Paul; Evans, Sam; Thomas, Rhys
2012-09-01
The aim of this study was to assess bone loss and thickness of the cut with the use of a burr in percutaneous hallux valgus surgery. Twelve blocks of saw bone were used. Cuts of same depth were made in each block with two different saw blades and a burr. Each block was assessed for bone loss and thickness of the cut. There was statistically significant (ptwo different saw blades. The use of a burr resulted in threefold increased loss of bone material and fourfold increase in the thickness of the cut as compare to use of two different saw blades. The metatarsal shortening is a risk factor in percutaneous hallux valgus surgery with the use of a burr. Copyright © 2011 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Lorkowski, Jacek; Trybus, Marek; Hładki, Waldemar; Brongel, Leszek
2006-01-01
The aim of our study was to estimate underfoot pressure distribution of a patient after bilateral hallux amputation and the unilateral calcaneal bone fracture on the left side at the end of orthopaedic end rehabilitation treatment. The pedobarographic examination during bipedal standing revealed localisation of maximal pressure at H region on the side of fracture and on MT1 and H foot regions on the other side. After the and of orthopaedic treatment underfoot pressure distribution changes persists in spite of pain regression.
CLINICAL CONCEPTION OF KELLER’S OPERATION FOR HALLUX VALGUS DEFORMITY——A SURVEY OF 112 CASES
葛茂之
1993-01-01
In a long-term follow-up study (average, 6.5 years) of 112 feet (90 pa-tients) subjected to Keller’s operation for hallux valgus deformity, the author observed arelationship between Keller’s operation and the metatarsalgia which was located beneaththe central metatarsal heads. The data showed that the metatarsalgia developed or was ag-gravated in 26 feet (23%), and was eliminated or alleviated in 23 feet (21%) afterKeller’s operation. When more than one-third of the proximal phalanx of the big toe wasresected, the incidence of the metatarsalgia obviously increased following surgery. Theautho rpreferred a "Z" lengthening of the extensor hallucis longus tendon instead ofresecting excessive proximal phalanx. The total incidence of the metatarsalgia was 36%(40 feet) preoperatively and 38% (43 feet) postoperatively. This result indicated thatthere was no obvious difference in the incidence of the preoperative and postoperativemetatarsalgia. No more than one-third of the proximal phalanx of the big toe should beremoved. This seems to reduce the incidence of the metatarsalgia after Keller’s operation.After operation, the three princepal symptoms of hallux valgus deformity, painful bunionand difficulty in shoe-wearing were improved for more than 95% in the 112 feet.Eighty one% of the patients were satisfied with the result of the operation. We considerthat this method is one of the effective operation for correcting the hallux valgusdeformity and it is also important to select suitable patients.
孙卫东; 吴夏勃; 戴鹤玲; 温建民; 胡海威; 孙永生; 桑志成; 蒋科卫; 梁朝; 程程; 林新晓
2010-01-01
Objective To evaluate the long-term results of minimal incision osteotomy for hallux valgus.Methods From February 1996 to May 1999,372 cases(705 feet)with hallux valgus were treated with minimal incision osteotomy.Seventy-nine cases after surgery were followed up for more than 5 years,including 6 males(10 feet)and 73 females(140 feet)with an average age of 47 years(range,13-75 years).The average follow-up time was 7.5 years(range,5.3-13.2 years).The preoperative and postoperative hallux valgus angles(HVA),intermetatarsal angles(IMA),the tibial sesamoid position(TSP),American orthopedic foot and ankle society(AOFAS)score,range of movement of the first metatarsophalangeal joint,and lateral metatarsalgia etc.were observed and measured.And the clinic outcome were studied and evaluated.Results Based on Wen Jian-min's clinic curative effect evaluation criterion(2001),56 feet(37.3%)were excellent,88 feet(58.7%)good ,6 feet(4.0%)fair.The rate of excellent or good was 96.0%(144/150).The postoperative mean AOFAS score was 84.20±4.32 points(range,60-100 points).The mean HVA decreased from 33.28 to 12.31 degrees,the mean IMA from 11.75 to 6.80 degrees.The TSP was corrected from an average preoperative grade of 4.29 to a grade of 3.07 at final follow-up.There are no nonunion or delayed union of osteotomy,avascular necrosis of the 1st metatarsal head,infection,hallux varus.Four feet(2.7%)had numbness in the medial of the big toe.The 1st metatarsophalangeal joint range of motion decreased from 70.20 to 69.53 degrees.There were 97 feet(64.7%)with the 2-5 metatarsalgia before operation,and 35 feet(23.3%)disappeared,54 feet(36.0%)improved,8 feet(5.3%)aggravated after operation.Conclusion Minimal incision osteotomy technique is sound and reliable method to treat hallux valgus.The osteotomy technique is simple,and could provide satisfactory long-term results with lower complication rate.%目的 评价微创截骨治疗(足母)外翻的远期疗效.方法 对1996年2月至1999年5月
杨波; 李强; 鲁英; 喻飞
2011-01-01
Objective To observe the outcomes of Ludloff proximal first metatarsal osteotomy. Methods Twentysix patients (34 feet) with a mean age of fifty-eight years underwent a modified Ludloff proximal first metatarsal osteotomy and a distal soft-tissue procedure at our hospital for the treatment of a moderate-to-severe hallux valgus deformity. The American Orthopaedic Foot and Ankle Society score and weight-bearing radiographs of the foot were assessed preoperatively and after a mean duration of follow-up of twenty-five months. Results The mean American Orthopaedic Foot and Ankle Society score improved significantly ( P ＜ 0. 01 ) from 52 points preoperatively to 88 points at the time of the most recent follow-up. The average hallux valgus angle improved from 31° preoperatively to 10. 3° at follow-up. The average intermetatarsal angle improved from 17° to 7. 8°. No severe complication has found. Conclusion Our intermodiateterm results demonstrate that the procedure achieves significant correction of moderate-to-severe hallux valgus deformity, significant reduction in forefoot pain, and significant improvement in functional outcome. This technique is valuable in correction of moderate to severe hallux valgus deformities.%目的 研究Ludloff截骨术对中、重度拇外翻的治疗效果.方法 2007年9月至2008年10月对26例(34足)中、重度拇外翻患者使用Ludloff截骨配合远端软组织手术进行矫形手术治疗,截骨使用螺钉固定.男4例,女22例,年龄48～67岁,平均58岁.术后采用AOFAS评分对患足进行临床功能评价,同时拍负重位足的正侧位X线片进行影像学评价,比较术后AOFAS评分及跖拇角和第一二跖间角的变化,了解患者的满意程度.结果 平均随访时间25个月(19～36个月).在最后一次随访时,31足基本无痛,3足偶有疼痛或轻微疼痛.患者对拇外翻畸形纠正满意.AOFAS评分为从术前的51分(27～65分)提高到术后的88分(72～96分),HVA从术前的31°(21
Luiz Carlos Ribeiro Lara
2012-12-01
Full Text Available OBJETIVO: Comparar clínica e radiograficamente os resultados da correção do hálux valgo, através de duas técnicas de osteotomia de adição: uma utilizando-se da exostose ressecada e outra, mediante a fixação com placa para cunha de adição. MÉTODOS: Avaliamos 24 pés em 19 pacientes, com média de idade de 51,3 anos, portadores de hálux valgo, com seguimento médio de 50,1 meses. Submeteram-se à técnica de osteotomia de adição com exostose óssea (OAEO 13 pés e à osteotomia de adição com placa para cunha de adição (OPCA 11 pés. Foram avaliados no pré e pós operatório o escore AOFAS, os ângulos intermetatársicos 1 e 2, e ângulo de valgismo do hálux. RESULTADOS: Na técnica OAEO a média no pré-operatório do AOFAS foi 46,6 pontos, AIM 14º e AVH 32º, enquanto no pós-operatório AOFAS 81,3 pontos, AIM 9º e AVH 25ºcom 92,3% de resultados satisfatórios. Na técnica OPCA a média no pré-operatório do AOFAS foi 42,1 pontos, AIM 15º e AVH 29º, enquanto no pós-operatório AOFAS 77,4 pontos, AIM 11º e AMF 23º com 81,8% de resultados satisfatórios. CONCLUSÕES: Ambas as técnicas cirúrgicas mostraram-se eficazes no tratamento do hálux valgo, clínica e radiograficamente, sem diferença estatística entre elas. Nível de evidência III, Estudo retrospectivo comparativo.OBJECTIVE: To clinically and radiographically compare the results of treatment of hallux valgus, by two addition osteotomy techniques: one using resected exostosis, and the other using a plate fixation for addition wedge. METHODS: We evaluated 24 feet of 19 patients, mean age 51.3 years, affected by hallux valgus, with a mean follow-up of 50.1 months. 13 feet underwent addition osteotomy with resected exostosis (AORE and 11 patients (11 feet underwent addition osteotomy with plate (AOP. The AOFAS score, intermetatarsal 1 and 2 angles, and hallux valgus angle were evaluated before and after surgery. RESULTS: In the AORE technique, the mean
孙建峰; 申杨勇; 韩斌; 陈京峰; 吴长喜; 李治斌; 崇辉; 顾敏琪
2012-01-01
[Objective] To retrospectively study and discuss the indications, surgical techniques and outcomes of selective distal osteotomy of the first metatarsal [Methods] From March 2007 to January 2011, 60 patients (101 feet) with hallux val-gus received distal osteotomy of the first metatarsal in our hospital, including 57 females and 3 males, with the mean age of 62.6 years (range ,23~81 years) . [ Results ] The followed - up period varied from 6 months to 4 years, wilh an average of 22 months. AU patients were evaluated with the American Orthopaedic Foot and Ankle Society ( AOFAS) hallux metatarsophalange-al - interphalangeal scale for the clinical assessment The excellent result was abtained in 40 (66 feet), good in 16 (30 feet) , and fair in 4 (5 feet) . The hallux valgus angles decreased from 36° (30°~44°) to 15. 3° (10. 5°~21°) . The intermetatar-sal angles were 16° (13°~18°) before surgery, and decreased to 8.5° (6°~10°) after surgery. The hallux metatarsophalan-geal joint range of motion increased from 16° (0°~30°) to 35° (25°~50°) . The length of the first metatareals decreasedby 4.2 mm (3-6 mm) . [ Conclusion ] This technique is of a soft - tissue and bone surgery, which has the advantages of minimal invasion, stable fixation and sufficiently plastic metatarsal head. It should be widely used in the clinical practice. decreasedby 4.2%[目的]探讨选择性跖骨远端截骨治疗(足母)外翻的手术适应证、手术方法及疗效.[方法]对2007年3月～2011年1月本院60例(101足)中度及重度(足母)外翻进行回顾性分析.双足41例,单足19例.其中女性57例,男性3例；年龄23～81岁,平均62.6岁.[结果]本组60例(101足)均获随访,随访时间6～48个月,平均22个月.参照美国足踝外科协会Maryland(足母)跖趾关节百分评分系统,90～ 100分40例(66足)；80～89分16例(30足)；70～79分4例(5足)；优良率95％.术前HVA 30°～44°,平均36°；术后10.5°～21°,平均15.3°.IMA 13
李昕宇; 林顺福; 王剑; 陈宇明; 王正义
2013-01-01
Objective To explore the curative effect of the operation of double wedge osteotomy of the first metatarsal for correction of severe hallux valgus.Methods The data of 62 patients (87 feet) with severe hallux valgus caused by enlarged distal metatarsal articular angle (DMAA) who were followed up after receiving the treatment of double wedge osteotomy of the first metatarsal from January 2008 to December 2011 were analyzed retrospectively.There are 9 males (14 feet),and 53 females (73 feet),with an average age of 56 years (range,28-70 years).Preoperative radiographs showed hallux valgus angle (HVA) was 48.6° in average,intermetatarsal angle (IMA) was 19.8° in average,and DMAA was 22.1° in avcragc.Thc opcration plan was made based on the preoperative deformity,and the osteotomy site,the angle,the capacity of osteotomy was all based on preoperative measurement.Compare the changes of HVA,IMA,DMAA before and after operation.The changes were also compared before and after the internal fixation extraction.The curative effect was observation based on American Orthopaedic Foot and Ankle Society (AOFAS) propodium score standard.Results Sixty-two patients (87 feet) were followed up for 10 to 57 months,with an average of 21 months.HVA (14.6°±1.2°),IMA (7.9°±0.7°),DMAA (7.7°±0.9°) were all satisfied 6 months after the operation.Stiff occurred in 2 patients after the operation.Cutaneous nerve injury occurred in 2 patients,and metastatic metatarsalgia occurred in 1 patient.No sever recurrence of deformity,bone nonunion and bone necrosis was found in all the patients.AOFAS score reached 91.8±1.8 one year after the operation,which was 28.4±9.1 preoperatively.Among them,49 feet were rated as excellent,31 as good,and 7 as fair.The excellent and good rate was 92％ (80/87).Conclusion The first metatarsal double osteotomy can effectively correct the severe hallux valgus deformity with enlarged DMAA with few complications.It achieves good effect.Patients can bear part of
如何治疗(足母)外翻%How to treat hallux valgus
陈宝兴
2002-01-01
@@ 本期有三篇分析(足母)外翻外科治疗效果的文 章.(足母)外翻(hallux abducto valgus,HAV)是足外科最常见的疾病,门诊患者几乎占2/3以上.HAV的治疗目的是矫正畸形,但曾有规定将(足母)外翻的治疗归为美容学范等,因而许多医院将(足母)外翻改称为(足母)囊炎(bunion,bursitis),实际上二者是并存的.(足母)外翻的病因有两种说法:遗传及鞋.北京足踝外科研究所的调查显示,20%的患者有家族史,但主要的原因还是"鞋".不穿鞋时,(足母)趾与跖骨在同一顺列,穿鞋后产生外翻角.
Ultrasound evaluation of intrinsic plantar muscles and fascia in hallux valgus
Lobo, César Calvo; Marín, Alejandro Garrido; Sanz, David Rodríguez; López, Daniel López; López, Patricia Palomo; Morales, Carlos Romero; Corbalán, Irene Sanz
2016-01-01
Abstract A cross-sectional area (CSA) and thickness reduction of the abductor hallucis (AbH) is shown in subjects with hallux valgus (HV). To date, other soft-tissue structures have not been researched in relation with HV. The aim of this study was to compare the CSA and thickness of the intrinsic plantar muscles and fascia (PF) between feet with and without HV. Therefore, a cross-sectional and case-control study was performed using B-mode with an iU22 Philips ultrasound system and a 5 to 17-MHz transducer. The CSA and thickness were measured for the AbH, flexor digitorum brevis (FDB) and flexor hallucis brevis (FHB), and also the thickness for the anterior, middle, and posterior PF portions. A convenience sample of 40 feet, 20 with HV and 20 without HV, was recruited from a clinical and research center. A multivariate regression analysis using linear regression was performed to evaluate the ultrasound imaging measurements (α = 0.05). Consequently, statistically significant differences were observed between the groups (P fascia thickness increase in favor of the HV group. On the contrary, the FDB thickness and CSA did not show statistically significant differences (P ≥ 0.05). In conclusion, the CSA and thickness of the AbH and FHB intrinsic plantar muscles are reduced, whereas the thickness of the anterior, middle, and posterior PF portions are increased, in subjects with HV compared with those without HV. PMID:27828846
Berillon, Gilles
1999-05-01
The degree of hallux abduction in extant and fossil hominoids is analysed in terms of geometric relationships between the first metatarsal and the medial cuneiform and quantified by angular data, in relation to grasping ability and locomotor pattern. The 'australopithecine' pattern corresponds to an abducted first podal ray with some grasping abilities and seems to be derived from a ' Proconsul-like' pattern rather than a 'living African great ape-like' pattern. The Olduvai Hominid 8 condition closely resembles that of the modern human which corresponds to a full bipedalism.
Goniometría (1993 Formación continuada)
Novel Martí, Virginia; Ogalla, José Manuel
1993-01-01
Con este artículo lo que se pretende es hacer un breve recordatorio de aquellas mediciones más útiles que podemos emplear en podología para la interpretación y diagnóstico de las placas radiológicas pre-quirúrgicas del hallux abductus valgo.
Choi, Jun Young; Suh, Yu Min; Yeom, Ji Woong; Suh, Jin Soo
2017-01-01
We aimed to compare the postoperative height of the second metatarsal head relative to the first metatarsal head using axial radiographs among 3 different commonly used osteotomy techniques: proximal chevron metatarsal osteotomy (PCMO), scarf osteotomy, and distal chevron metatarsal osteotomy (DCMO). We retrospectively reviewed the radiographs and clinical findings of the patients with painful callosities under the second metatarsal head, complicated by hallux valgus, who underwent isolated PCMO, scarf osteotomy, or DCMO from February 2005 to January 2015. Each osteotomy was performed with 20 degrees of plantar ward obliquity. Along with lateral translation and rotation of the distal fragment to correct the deformity, lowering of the first metatarsal head was made by virtue of the oblique metatarsal osteotomy. Significant postoperative change in the second metatarsal height was observed on axial radiographs in all groups; this value was greatest in the PCMO group (vs scarf: P = .013; vs DCMO: P = .008) but did not significantly differ between the scarf and DCMO groups ( P = .785). The power for second metatarsal height correction was significantly greater in the PCMO group (vs scarf: P = .0005; vs DCMO: P = .0005) but did not significantly differ between the scarf and DCMO groups ( P = .832). Among the 3 osteotomy techniques commonly used to correct hallux valgus deformity, we observed that PCMO yielded the most effective height change of the second metatarsal head. Level III, retrospective comparative series.
闫行超; 刘志刚; 潘月海; 贾晓燕; 刘鉴锋; 张亚楠; 邵江波; 刘彬
2015-01-01
Objective To explore the curative effect of clinical application of modified McBride's procedure on correcting mild-moderate hallux valgus.Methods We had retrospectively assessed 32 patients(52 feet)treated with the procedure of modified McBride's procedure.All patients were followed up,the follow -up period from 6 months to 6 years(3.1 years on average).There were 2 male(4 feet)patients and 30 female(48 feet)patients in this group.The average age at the time of surgery was 41.6 years old(from 21 to 59 years).Results According to the forefoot score of American Orthopedics Foot and Ankle Society(AOFAS),29 feet(55.8%)were excellent,17 feet (32.7%)were good,And the rate of excellent and good was 88.5%.The average correction of HVA and IMA was 13.68°and 3.24°respectively compared with the preoperative cases.Conclusion This procedure can not only effec-tively reduce the increased hallux valgus angle,but also narrow the angle between the 1st and 2nd metatarsal,relocate the sesamoid system,and effectively relieve patients'pain.This approach is of minor side effects to bone and joint structure,and of rapid recovery.It is a preferential choice to treat mild-to-moderate hallux valgus deformity.%目的：探讨改良Mcbride术治疗轻、中度拇外翻的临床疗效。方法选取采用改良Mcbride术治疗的拇外翻32例（52足），均获得随访，随访时间为6个月至6年，平均3．1年；男2例4足，女30例48足，手术年龄在21～59岁，平均41．6岁。结果参照美国足踝外科协会（AOFAS）前足评分系统对所有患者进行评定，优29足（55．8％），良17足（32．7％），优良率为88．5％；拇外翻角（HVA）较术前平均纠正了13．68°，第一、二跖骨间角（IMA）较术前平均纠正了3．24°。结论此术式能有效地减小增大的拇外翻角，同时也缩小第1、2跖骨间角，复位相对脱位的籽骨，有效地去除或减缓拇囊炎症状。此方法创伤小，恢复快，能较
V. P. Pavlov
2014-01-01
Full Text Available Objective: to study results of arthrodesis of the first metatarsophalangeal joint (I MPT joint in patients with rheumatoidarthritis (RA and hallux valgus, assess methods of arthrodesis fixation, reveal complications and analyze longterm results.Subjects and methods. Authors observed 86 patients with RA, female : male ratio 3.2:1, mean age was 53.8±9.5 years (from 18 to 75 years; 80 from them had seropositive and 6 – seronegative RA. 72 patients had low, and 14 –moderate activity of the disease. II stage of RA was revealed in 31.4%, III – in 62.8%, IV – in 5.8%; 52.3% of patients had I and 47.7% – II functional class. All patients ad hallux valgus as a component of typical deformation of the forefoot – digitis V rheumaticus (DVR. Standard global reconstructive operation (SGRO and its modification (MGRO were used. Both techniques included arthrodesis of the I MTP joint where fusion of bones was fixed with Kirschner wire and compression clamps in groups A and B respectively. Results of surgical treatmentwere assessed separately for I and II–V toes. The present work provides solely the results of the I MTP joint arthrodesis.Results. Assessment of the I MTP joint with hallux valgus before and 2.3±1.5 years after operation based on AOFAS comprised 35.51±8.16/82.32±6.09 in the group A and 39.93±6.65/82.26±5,59 in the group B. Inefficiency of arthrodesis of the I MTP joint was observed in 3 patients from the group B (2.15%. Before operation, 3 from 141 feet had hallux valgus of the II stage (21–40°; III (41–60° and IV (>60° stages of hallux valgus were recorded in 90 and48 feet respectively. Following 2.3 years after arthrodesis normal I MTP joints (10–11° were observed in 131 feet whereas, that of the II stage of hallux valgus (12–20° – in 10 feet.Conclusion. High efficacy of arthrodesis of the I MTP joint in patients with RA and hallux valgus and, subsequently, low failure rate (2.15% were achieved as
Prevalence of hallux valgus in the general population: a systematic review and meta-analysis
Vicenzino Bill
2010-09-01
Full Text Available Abstract Background Hallux valgus (HV is a foot deformity commonly seen in medical practice, often accompanied by significant functional disability and foot pain. Despite frequent mention in a diverse body of literature, a precise estimate of the prevalence of HV is difficult to ascertain. The purpose of this systematic review was to investigate prevalence of HV in the overall population and evaluate the influence of age and gender. Methods Electronic databases (Medline, Embase, and CINAHL and reference lists of included papers were searched to June 2009 for papers on HV prevalence without language restriction. MeSH terms and keywords were used relating to HV or bunions, prevalence and various synonyms. Included studies were surveys reporting original data for prevalence of HV or bunions in healthy populations of any age group. Surveys reporting prevalence data grouped with other foot deformities and in specific disease groups (e.g. rheumatoid arthritis, diabetes were excluded. Two independent investigators quality rated all included papers on the Epidemiological Appraisal Instrument. Data on raw prevalence, population studied and methodology were extracted. Prevalence proportions and the standard error were calculated, and meta-analysis was performed using a random effects model. Results A total of 78 papers reporting results of 76 surveys (total 496,957 participants were included and grouped by study population for meta-analysis. Pooled prevalence estimates for HV were 23% in adults aged 18-65 years (CI: 16.3 to 29.6 and 35.7% in elderly people aged over 65 years (CI: 29.5 to 42.0. Prevalence increased with age and was higher in females [30% (CI: 22 to 38] compared to males [13% (CI: 9 to 17]. Potential sources of bias were sampling method, study quality and method of HV diagnosis. Conclusions Notwithstanding the wide variation in estimates, it is evident that HV is prevalent; more so in females and with increasing age. Methodological quality
孙洋; 吴俊; 马海东; 曲家富; 曹立海; 赵国志; 高建华; 彭义; 李绍光; 杜晓健; 王良
2012-01-01
, uncomfortable walking, re-displacement of osteotomized ends and stiffness of the first metatarsophalangeal joint. Objective: The purpose of the study is to explore the clinical outcomes of minimally invasive three-dimensional correction with limited fixation for treating hallux valgus. Methods: From July 2005 to October 2010, 151 patients with hallux valgus (281 feet) underwent minimally invasive three-dimensional correction and limited fixation with Kirschner wire. Among them, 132 patients (245 feet) were followed up. There were 8 males and 124 females. The age of the patients ranged from 16 to 76 years (50.2±10.3 years). Some parameters, including hallux valgus angle (HVA), intermetatarsal angle (IMA), interphalangeal angle (IPA), proximal articular set angle(PASA), distal articular set angle(DASA), metatarsal cuneiform angle(MCA), AOFAS and propodium pressure were compared before and after the surgery. Results: The follow-up time ranged from 2 to 6.25 years (average, 3.9 years). There were 236 feet without recurrence and 6 feet with recurrence. Metatarsophalangeal arthritis occurred in 3 feet, which were cured after arthrodesis. The pain in the corpus callosum at the bottom of the second and third metatarsal heads alleviated in the early stage, and the pain gradually disappeared in 233 feet at later stage, while the pain did not completely disappear in 12 feet. Numbness in the dorsum of thumb occurred in 6 feet. The range of motion of metatarsophalangeal joint ranged from 4° to 9° in 15 feet. The wounds healed at phase I in all the patients. No infection, nonunion, metatarsal head necrosis and Kirschner wire breaking occurred. Postoperative X-rays showed that HVA was less than 20 ?and IMA was less than 10 ?in the 245 feet. There were significant differences in the measured angles and AOFAS score before and after surgery (P< 0.001). The preoperative descending order of pressure of the front foot sole was the second, third, first, fourth and fifth head of metatarsal bone
手术治疗拇外翻218例的临床症状分析%Clinical Symptoms of 218 Patients with Hallux Valgus Undergoing Operation
黄加张; 马昕; 王旭; 张超; 顾湘杰; 陈立
2011-01-01
Objective To analyze presenting symptoms of hallux valgus and the relationship between presenting symptoms and hallvu valgus stage. Methods All of 218 patients (291 feet) with hallux valgus admitted to Huashan Hospital in 2004~2009 were analyzed. According to presenting symptoms: bunion, less toe deformity, forefoot planter pain. According to X-ray assessment: mild, moderate or severe hallux valgus. Results Many kinds of presenting symptoms were reported:27 feet with bunion, 47 feet with less toe deformity, 14 feet with forefoot planter pain, 205 feet with two or three presenting symptoms. Mild, moderate and severe hallux valgus were 58, 108 and 125 feet respectively. The magnitude of hallux valgus deformity was not related with bunion or fore planter pain (P ≥0.05). Severe hallux valgus was significantly related with less toe deformity (P <0.05). Two or three presenting symptoms were significantly related with moderate or severe hallux valgus (P<0.05). Presenting symptoms of moderate and severe hallux valgus were not significantly related (P ≥0.05). Conclusion There are many presenting symptoms of hallux valgus, each of them with its own particular pathogenesis and problems. Different procedures should depend on not only X-ray assessment but also presenting symptoms and other deformities.%目的 探讨拇外翻患者就诊手术原因及与分度的关系.方法 收集2004年1月～2009年8月复旦大学附属华山医院手术治疗拇外翻218例(291足)的临床资料,根据临床症状分为四类:单纯跖骨头内侧疼痛,单纯小趾畸形,单纯前足胼胝疼痛.根据X线测量拇外翻角、跖骨间角分为轻度、中度、重度.结果 拇外翻患者就诊原因多种多样,其中单纯拇囊炎疼痛27足,单纯小趾畸形疼痛45足,单纯前足疼痛14足,有两项或两项以上症状205足.根据X线分型:轻度拇外翻58足,中度拇外翻108足,重度拇外翻125足.单纯拇囊炎疼痛、单纯前足疼痛与拇外
V. M. Mashkov
2013-01-01
Full Text Available Objective: to determine the opportunity of usage of Schede-Brandes procedure in the treatment of patients with hallux valgus. Material and methods. The results of Shede-Brandeis operation were studied in 119 patients (198 feet. The study included patients who were followed up long-term results of treatment for up to 10 years. The results of the surgical treatment were assessed by the AOFAS scale and total criteria proposed I.A. Pakhomov. According to these scales the following results were obtained: the good - in 59,59% of patients, satisfactory - in 22,73%, poor - in 17,68%. Conclusion. These results allow to recommend Schede-Brandes procedure for use in elderly patients with osteoporosis, concomitant vascular diseases of lower extremities and with rheumatoid arthritis.
Quality of Life Impact Related to Foot Health in a Sample of Older People with Hallux Valgus
López, Daniel López; Callejo González, Lucía; Iglesias, Marta Elena Losa; Canosa, Jesús Luis Saleta; Sanz, David Rodríguez; Lobo, Cesar Calvo; de Bengoa Vallejo, Ricardo Becerro
2016-01-01
Hallux Valgus (HV) is a highly prevalent forefoot deformity in older people associated with progressive subluxation and osteoarthritis of the first metatarsophalangeal (MTP) joint and it is believed to be associated with varying degrees of HV effect on the quality of life related to foot health. The aim of this study is to compare the impact of varying degrees of HV on foot health in a sample of older people. The sample consisted of 115 participants, mean age 76.7 ± 9.1, who attended an outpatient center where self-report data were recorded. The degree of HV deformity was determined in both feet using the Manchester Scale (MS) from stage 1 (mild) to 4 (very severe). Scores obtained on the Foot Health Status Questionnaire (FHSQ) were compared. This has 13 questions that assess 4 health domains of the feet, namely pain, function, general health and footwear. The stage 4 of HV shown lower scores for the footwear domain (11.23 ± 15.6); general foot health (27.62 ± 19.1); foot pain (44.65 ± 24.5); foot function (53.04 ± 27.2); vigour (42.19 ± 16.8); social capacity (44.46 ± 28.1); and general health (41.15 ± 25.5) compared with stage 1 of HV (P<0.05) and there were no differences of physical activity (62.81 ± 24.6). Often, quality of life decreases in the elderly population based in large part on their foot health. There is a progressive reduction in health in general and foot health with increasing severity of hallux valgus deformity which appears to be associated with the presence of greater degree of HV, regardless of gender. PMID:26816663
陈新宇
2014-01-01
目的：探讨 Silver 手术联合 Akin 截骨术治疗足拇外翻老年患者的临床疗效。方法选取2010年1月至2012年12月收治的足拇外翻老年患者40例。给予 Silver 手术联合 Akin 截骨术治疗，术后不采用外固定，尽早下床功能锻炼。随访并观察统计患者外翻角（HVA）、跖间角（IMA）和近侧关节固定角（PASA）的变化，疗效客观评价采用美国足踝外科协会（AOFAS）评分系统，采用自制调查表进行满意度调查。结果术前 HVA（29.65±4.79）°，术后矫正到（10.41±3.37）°，差异有统计学意义（t =27.47，P ﹤0.01），术前 IMA（9.47±2.48）°，术后矫正到（8.37±2.58）°，差异有统计学意义（t =3.21，P ﹤0.05）。术前 AOFAS 评分（28.37±5.81）术后提高到（82.74±10.76），具有统计学意义（t =35.71，P ﹤0.05）。结论 Silver 手术联合 Akin 截骨术治疗轻中度足拇外翻老年患者，矫正效果佳、复发率低，同时因不需要外固定，术后允许早期负重锻炼，可有效降低老年人围术期并发症发生率。%Objective To investigate the clinical curative effect of Silver operation combined with Akin osteotomy on elderly hallux valgus. Methods Forty cases of elderly hallux valgus patients from January 2010 to December 2012 were selected. All of the patients were given Silver operation com-bined with Akin osteotomy surgery treatment,with no external fixation after operation,and they all took functional exercise as soon as possible. The hallux valgus angle(HVA),intermetatarsal angle(IMA) and proximal articular set angle(PASA)were followed - up and observed. The curative effect was evalu-ated objectively by the American Orthopaedic Foot and Ankle Society(AOFAS)scoring system,and self-designed questionnaire was used for satisfaction survey. Results HVA was(29. 65 ± 4. 79)° before op-eration and it was corrected to the(10. 41 ± 3. 37)°after operation,there was significant
俞光荣; 樊健; 周家钤; 李海丰; 杨云峰; 李兵
2011-01-01
目的 探讨经单一内侧切口Austin跖骨截骨联合(母)收肌、跖横韧带切断治疗轻中度(母)外翻的临床疗效.方法 2006年5月-2009年1月,收治41例45足轻中度(母)外翻.男9例10足,女32例35足;年龄23～71岁,平均45.3岁.左足22例,右足15例,双足4例.(母)外翻角(halluxvalgus angle,HVA)为(33.1±1.4)°,第1、2跖间角为(20.4±1.1)°.患足功能根据美国矫形足踝协会(AOFAS)踝与后足评分标准评分为(47.2±3.7)分.于第1趾跖关节内侧作纵形切口,同时完成Austin跖骨截骨及(母)收肌、跖横韧带等外侧软组织松解术.结果 术中1足腓浅神经足背支损伤,行显微缝合修复.术后患者切口均Ⅰ期愈合.41例均获随访,随访时间16～36个月,平均26个月.术后3 d 2足出现前足内侧麻木,6周内自行缓解.X线片检查示截骨处均于8周内达骨性愈合.末次随访时HVA为(10.7±1.7)°,与术前比较差异有统计学意义(t=22.32,P=0.00);第1、2跖间角为(12.1±1.7)°,与术前比较差异亦有统计学意义(t=21.17,P=0.03).AOFAS踝与后足评分为(84.9±4.5)分,与术前比较差异有统计学意义(t=20.75,P=0.01).随访期间无(母)内翻、(母)外翻及跖骨头坏死等并发症发生.结论 经单一内侧切口Austin跖骨截骨联合(母)收肌、跖横韧带等外侧软组织松解能有效矫正轻中度(母)外翻,手术创伤小,避免了外侧切口瘢痕及腓深神经分支损伤等并发症的发生.%Objective To evaluate the primary clinical effectiveness of Austin metatarsal osteotomy combined with transection of adductor muscle and transverse metatarsal ligament for treating mild or moderate hallux valgus through a single medial incision. Methods Between May 2006 and January 2009, 41 patients (45 feet) with mild or moderate hallux valgus were treated. There were 9 males (10 feet) and 32 females (35 feet) with an average age of 45.3 years (range, 23-71 years). The hallux valgus angle (HVA
A new angle on the Euler angles
Markley, F. Landis; Shuster, Malcolm D.
1995-01-01
We present a generalization of the Euler angles to axes beyond the twelve conventional sets. The generalized Euler axes must satisfy the constraint that the first and the third are orthogonal to the second; but the angle between the first and third is arbitrary, rather than being restricted to the values 0 and pi/2, as in the conventional sets. This is the broadest generalization of the Euler angles that provides a representation of an arbitrary rotation matrix. The kinematics of the generalized Euler angles and their relation to the attitude matrix are presented. As a side benefit, the equations for the generalized Euler angles are universal in that they incorporate the equations for the twelve conventional sets of Euler angles in a natural way.
... Programs Home > Statistics and Data > Glaucoma, Open-angle Glaucoma, Open-angle Open-angle Glaucoma Defined In open-angle glaucoma, the fluid passes ... 2010 2010 U.S. Age-Specific Prevalence Rates for Glaucoma by Age and Race/Ethnicity The prevalence of ...
Faulí, A; Anglada, M T; Gomar, C; Sala, X; López, A; Pons, M; Gambús, P; Fábregas, N
2012-12-01
To compare 3 combinations of 0.5% levobupivacaine (L) and 1% mepivacaine (M) for popliteal block for hallux valgus surgery. Prospective, double blind study of 120 patients undergoing unilateral hallux valgus outpatient surgery with posterior popliteal block with ultrasound-guided single injection. Patients were randomly allocated into three groups: G1: 20mL L+10mL M; G2: 10mL L+20mL M; and G3: 15mL L+15mL M. Recorded variables were: time of block, onset and reversal times for tibial and peroneal nerves block; postoperative pain until the 7(th) day by means of visual analogue scale (VAS), simple descriptive scale and the quality of nocturnal rest, complications, and patient satisfaction. ANOVA and chi2 were applied in the statistical analysis, with a Pmepivacaine 1% provide a good alternative for a lasting postoperative analgesia. Copyright © 2011 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.
Nixon, Devon C; McCormick, Jeremy J; Johnson, Jeffrey E; Klein, Sandra E
2017-08-23
Traditional patient-reported outcome instruments like the Foot and Ankle Ability Measure (FAAM) quantify patient disability but often are limited by responder burden and incomplete questionnaires. The Patient-Reported Outcome Measurement Information System (PROMIS) overcomes such obstacles through computer-adaptive technology and can capture outcome data from various domains including physical and psychosocial function. Prior work has compared the FAAM with PROMIS physical function; however, there is little evidence comparing the association between foot and ankle-specific tools like the FAAM with more general outcomes measures of PROMIS pain interference and depression in foot and ankle conditions. (1) We asked whether there was a relationship between FAAM Activities of Daily Living (ADL) scores with PROMIS physical function, pain interference, and depression in patients with hallux valgus. (2) Additionally, we asked if we could identify specific factors that are associated with variance in FAAM and PROMIS physical function scores in patients with hallux valgus. Eighty-five new patients with either a primary or secondary diagnosis of hallux valgus based on clinic billing codes from July 2015 to February 2016 were retrospectively identified. Patients completed FAAM ADL paper-based surveys and electronic PROMIS questionnaires for physical function, pain interference, and depression from new patient visits at a single time. Spearman rho correlations were performed between FAAM ADL and PROMIS scores. Analyses then were used to identify differences in FAAM ADL and PROMIS physical function measures based on demographic variables. Stepwise linear regressions then determined which demographic and/or outcome variable(s) accounted for the variance in FAAM ADL and PROMIS physical function scores. FAAM scores correlated strongly with PROMIS physical function (r = 0.70, p < 0.001), moderately with PROMIS pain interference (r = -0.65, p < 0.001), and weakly with PROMIS
Karow, Jens-Hagen; Abt, Hans-Peter; Fröhling, Markus; Ackermann, Hanns
2008-01-01
This study was undertaken to answer the question: "Is Arnica D4 as efficacious as diclofenac in relation to symptoms and wound healing after foot surgery?" In this randomized double-blinded, parallel-group study (GCP-standard), the efficacy of Arnica D4 10 pillules (taken orally, 3 times per day) and diclofenac sodium, 50 mg (taken orally, 3 times per day) were investigated for equivalence in 88 patients 4 days after hallux valgus surgery. Outcome parameters were (1) postoperative irritation, (2) patient mobility, (3) rated pain, and (4) use of analgesics. The hierarchic equivalence test based on one-sided Wilcoxon-Mann-Whitney-U confidence intervals (CIs) was used. Equivalence was perceived, when the lower margin of the 95% CI was > 0.36 corresponding to a range of equivalence of 1/2 standard deviation. Arnica D4 and diclofenac were equivalent for wound irritation (lower margin of the 95% CI on day 4: 0.4729 for rubor; 0.3674 for swelling; 0.4106 for calor) and patient mobility (0.4726). A descriptive analysis showed the superiority of Arnica D4 with respect to patient mobility (p = 0.045). With respect to pain, Arnica D4 was inferior to diclofenac (lower margin of the 95% CI 0.026). No significant differences were found regarding the use of additional analgesics during the 4 postoperative days (Dipidolor, Janssen-Cilag, Neuss, Germany; p = 0.54; Tramal, Grünenthal, Aachen, Germany; p = 0.1; and Novalgin, AVENTIS-Pharma, Bad Soden, Germany; p = 0.1). Arnica D4 was significantly better tolerated than diclofenac (p = 0.049). Nine (9) patients (20.45%) of the diclofenac group and 2 (4.5%) of the Arnica D4 group reported intolerance. There was no disturbance in wound healing in any of the patients. Arnica D4 is 60% cheaper than diclofenac. After foot operations, Arnica D4 can be used instead of diclofenac to reduce wound irritation.
Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...
孙卫东; 温建民; 胡海威; 孙永生; 成永忠; 王庆雷
2012-01-01
Objective To analyze the relationship between the osteotomy stability and the different osteotomy angles on the first metatarsal neck of hallux valgus, and to explore the best osteotomy angle to maintain osteotomy stability. Methods Finite element osteotomy models of hallux valgus were established. Seven kinds of working conditions were simulated, which of the osteotomy line and the first metatarsal axis were angulated in 30°, 45°, 60°, 75°, 90°, 105°, 120° on the sagittal plane. The proximal osteotomy segment was set as fixed segment, the distal as the free segment. Between the two sides granulation tissue was set to fill with. A hallux valgus patient' s single foot with 62 kg body weight was bear about 310 N loads. The effects of flexor pollicis longus and flexor pollicis brevis muscle were considered to the osteotomy segment only when standing with hallux plantar flexion after osteotomy. Muscle strength was set parallel to the long axis of the first metatarsal and expressed load. The friction coefficient between the osteotomy segments was set to 0. 6. We calculated the maximum Von Mises stress and the total displacement V value of osteotomy segment edge node of 7 kinds of working conditions on the above constraints and loading conditions, and compared the calculations. Results The total displacement V value of osteotomy segment diminished gradually from 30° , reached to the minimum at 60° , and then increased significantly as osteotomy angle exceeded 90°. The Von Mises stress of osteotomy segment increased gradually from 30°, reached the first peak at 75° , and then flattened and reduced gradually. The stress increased rapidly at 105°. Conclusions Only keep the osteotomy direction of the first metatarsal on the sagittal plane from the distal dorsal to proximal plantar side, can the osteotomy segment maintain stability. It is at 60° or so that the osteotomy segment was the most stable. The best osteotomy angle needs adjustment according to different
Perugia, Dario; Fabbri, Mattia; Guidi, Marco; Lepri, Marco; Masi, Vincenzo
2014-12-01
The purpose of this study was to describe four exceptional cases of Salter-Harris type III and IV fractures of the proximal phalanx of the hallux in young high-level gymnasts. All gymnasts underwent the same mechanism of injury of hyperadduction, which indicates a role of the abductor hallucis muscle in the genesis and displacement of these fractures. An open reduction and internal fixation was performed to achieve an anatomical reduction and avoid chronic disability. At 1-year follow-up, all patients had an excellent American Orthopaedic Foot and Ankle Society (AOFAS) score (100 points), and there was no shortening or angulation of the first ray and no evidence of degenerative joint disease on X-ray. Moreover, all the gymnasts had returned to pre-injury levels of sporting activity. To our knowledge, there are no previous studies that address these types of injuries and how they are handled in gymnasts.
Bunions (Hallux Abducto Valgus)
... front part of the foot. The big toe leans toward the second toe, rather than pointing straight ... ankle surgeons. All Fellows of the College are board certified by the American Board of Foot and ...
Demographic, physical, and radiographic factors associated with functional flatfoot deformity.
Shibuya, Naohiro; Kitterman, Ryan T; LaFontaine, Javier; Jupiter, Daniel C
2014-01-01
In 1 of our previous studies, the occurrence of self-reported flatfoot was associated with self-reported increased age, male gender, Asian and African American races, veteran status, poor health, increased body mass index, callus, bunion, hammertoe, and arthritis. However, we had to rely on survey data to identify these risk factors, and the accuracy of the survey results was unknown. Therefore, we decided to identify the risk factors associated with flatfeet using objectively and more accurately measured data. A total of 94 patients were enrolled in the present study. The demographic data and physical and radiographic examination results were recorded by the investigators in the clinic. The data were then analyzed to identify the factors unique to flatfoot, measured and defined using a plantar pressure measurement system during natural gait. We learned that a painful tibialis posterior tendon was associated with flatfoot. The calcaneal inclination angle was also decreased in the flatfoot group. The talar declination, intermetatarsal, hallux abductus, and calcaneal cuboid angles, and static calcaneal stance eversion were elevated in the flatfoot group compared with the non-flatfoot group. Systematic evaluation of these associated factors will help in the understanding of the functional status of the flatfoot deformity.
Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.
2014-01-01
Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…
Podzharenko, Volodymyr A.; Kulakov, Pavlo I.
2001-06-01
The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.
A survey on the relationship between wedge heel of nurse shoes and hallux valgus%坡跟护士鞋与足拇外翻的相关性研究
胡婷
2013-01-01
Objective To investigate the relationship between the heel design of nurse shoes and the incidences of hallux valgus. The findings of this study will help clinical nurses to choose right shoes to keep the occupational safety. Methods To investigate 87 clinical nurses in different department through answering the questionnaire designed by the investigator. Results 63.2% clinical nurses felt squeezing wearing wedge heel of nurse shoes, 69% clinical nurses showed that wedge heel of nurse shoes could contribute the pain of the hallux joint. The working position and the extent of squeezing of shoes have positive relationship with the pain of po-darthrum (P<0.05), and the wedge heel has positive relationship with hallux valgus(P<0.01).Conclusion The result of the study demonstrated that the wedge heel of nurse shoes will cause hallux valgus. Therefore, wedge heel of the nurse shoes should not be de-signed for reducing the occurence of hallux valgus in clinical nurses.%目的研究护士鞋跟设计与诱发拇外翻的相关性，为临床护士选择合适的工作鞋从而改善护士职业安全提供依据。方法采用自行设计的调查问卷，对87例各科临床护士进行护士鞋跟设计对足部影响的调查。结果63.2%的护士认为坡跟护士鞋的鞋尖处感觉狭窄，认为工作时穿着坡跟护士鞋会感足趾关节疼痛的护士占69%，护士的工作状态、护士鞋对足趾挤压程度与坡跟鞋引起的足趾关节疼痛呈正相关（P<0.05），且坡跟鞋引起的足趾关节疼痛又与拇外翻发生呈正相关（P<0.01）。结论护士鞋坡跟设计增加了拇外翻病变的发生几率，针对护士群体，及护士特殊工作状态，应减少采取护士鞋坡跟设计，以改善临床护士的职业健康状况。
闫行超; 刘鉴峰; 刘彬; 刘志刚; 潘月海; 贾晓燕; 张亚楠; 邵江波
2015-01-01
目的 探讨(踇)收肌与(踇)展肌移位吻接重建前足横弓矫治(踇)外翻畸形的疗效.方法 回顾分析2010年1月-2014年1月,采用(踇)收肌与(踇)展肌移位吻接重建前足横弓治疗并获随访的28例(40足)(踇)外翻畸形患者临床资料.其中男3例(6足),女25例(34足);年龄20～71岁,平均51.7岁.单足16例,双足12例.病程1～ 30年,平均8.9年.患者均有不同程度(踇)囊炎表现;22足有明显前足横弓塌陷并足底胼胝,8足合并锤状趾畸形.美国足踝外科协会(AOFAS)评分为(59.07±8.49)分.术前X线片示(踇)外翻角(hallux valgus angle,HVA)(33.68±8.10)°,跖间角(intermetatarsal angle,IMA)(15.60±4.07)°.根据Mann(踇)外翻分类标准,轻度9足,中度23足,重度8足.结果 术后1例(1足)切口感染,其余切口均Ⅰ期愈合.2例(3足)出现(踇)趾麻木.28例均获随访,随访时间6个月～4年,平均1.8年.末次随访时根据AOFAS评分量表评定疗效:获优24足,良9足,可4足,差3足;优良率为82.5％.末次随访时,HVA为(15.10±5.28)°,IMA为(9.05±2.42)°,AOFAS评分为(86.03±7.45)分,与术前比较差异均有统计学意义(P=0.00).伴前足横弓塌陷者横弓均有一定程度恢复,足底胼胝消失(14足)或变小(8足).2例(3足)分别于术后3个月和2个月时(踇)外翻复发,无(踇)内翻发生.结论 (踇)收肌与(踇)展肌移位吻接重建前足横弓矫治(踇)外翻畸形,能减小HVA及IMA,复位脱位籽骨,重建前足横弓,有效恢复前足生理解剖结构及功能.
Farley, Gary L.
1990-01-01
Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.
Kim, Taeho; Lee, Dong Yeon; Park, Jinah
2016-03-01
Clinical management of foot pathology requires accurate and robust measurement of the anatomical angles. In order to measure a 3D angle, recent approaches have adopted a landmark-based local coordinate system to establish bone angles used in orthopedics. These measurement methods mainly assess the relative angle between bones using a representative axis derived from the morphological feature of the bone and therefore, the results can be affected by bone deformities. In this study, we propose a method of deriving a global frame-of-reference to acquire consistent direction of the foot by extracting the undersurface of the foot from the CT image data. The two lowest positions of the foot skin are identified from the surface to define the base plane, and the direction from the hallux to the fourth toe is defined together to construct the global coordinate system. We performed the experiment on 10 volumes of foot CT images of healthy subjects to verify that the proposed method provides reliable measurements. We measured 3D angles for talus-calcaneus and talus-navicular using facing articular surfaces of paired bones. The angle was reported in 3 projection angles based on both coordinate systems defined by proposed global frame-of-reference and by CT image planes (saggital, frontal, and transverse). The result shows that the quantified angle using the proposed method considerably reduced the standard deviation (SD) against the angle using the conventional projection planes, and it was also comparable with the measured angles obtained from local coordinate systems of the bones. Since our method is independent from any individual local shape of a bone, unlike the measurement method using the local coordinate system, it is suitable for inter-subject comparison studies.
Kim, Ho Kyung; Cho, Min Kook; Kim, Seong Sik [Pusan National University, Busan (Korea, Republic of)
2007-07-01
In computed tomography (CT), many situations are restricted to obtain enough number of projections or views to avoid artifacts such as streaking and geometrical distortion in the reconstructed images. Speed of motion of an object to be imaged can limit the number of views. Cardiovascular imaging is a representative example. Size of an object can also limit the complete traverse motion or geometrical complexity can obscure to be imaged at certain range of angles. These situations are frequently met in industrial nondestructive testing and evaluation. Dental CT also suffers from similar situation because cervical spine causes less x-ray penetration from some directions such that the available information is not sufficient for standard reconstruction algorithms. The limited angle tomography is now greatly paid attention as a new genre in medical and industrial imaging, popularly known as digital tomosynthesis. In this study, we introduce a modified filtered backprojection method in limited angle tomography and demonstrate its application for the dental imaging.
Maeda, Kei-ichi; Uzawa, Kunihito
2016-12-01
We discuss the dynamical D p -brane solutions describing any number of D p branes whose relative orientations are given by certain SU(2) rotations. These are the generalization of the static angled D p -brane solutions. We study the collision of the dynamical D3 brane with angles in type-II string theory, and show that the particular orientation of the smeared D3-brane configuration can provide an example of colliding branes if they have the same charges. Otherwise a singularity appears before D3 branes collide.
Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona
2012-01-01
: Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...
Contact angle hysteresis explained.
Gao, Lichao; McCarthy, Thomas J
2006-07-04
A view of contact angle hysteresis from the perspectives of the three-phase contact line and of the kinetics of contact line motion is given. Arguments are made that advancing and receding are discrete events that have different activation energies. That hysteresis can be quantified as an activation energy by the changes in interfacial area is argued. That this is an appropriate way of viewing hysteresis is demonstrated with examples.
Morgan, Jeannie; Lynnerup, Niels; Hoppa, R.D.
2013-01-01
measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability...... method appears to be of minimal practical use in forensic anthropology and archeology. © 2013 American Academy of Forensic Sciences....
Relationship between the Angle of Repose and Angle of Internal ...
Keywords: Angle of repose, angle of internal friction, granular materials, triaxial compression ... such a granular material is sharp, making a steep .... study. Therefore, grains had to be condi- tioned to the respective moisture contents by adding ...
Variable angle correlation spectroscopy
Lee, Y K [Univ. of California, Berkeley, CA (United States)
1994-05-01
In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.
Landorf Karl B
2009-01-01
Full Text Available Abstract Background Osteoarthritis of the first metatarsophalangeal joint (MPJ of the foot, termed hallux limitus, is common and painful. Numerous non-surgical interventions have been proposed for this disorder, however there is limited evidence for their efficacy. Intra-articular injections of hyaluronan have shown beneficial effects in case-series and clinical trials for the treatment of osteoarthritis of the first metatarsophalangeal joint. However, no study has evaluated the efficacy of this form of treatment using a randomised placebo controlled trial. This article describes the design of a randomised placebo controlled trial to evaluate the efficacy of intra-articular hyaluronan (Synvisc® to reduce pain and improve function in people with hallux limitus. Methods One hundred and fifty community-dwelling men and women aged 18 years and over with hallux limitus (who satisfy inclusion and exclusion criteria will be recruited. Participants will be randomised, using a computer-generated random number sequence, to receive a single intra-articular injection of up to 1 ml hyaluronan (Synvisc® or sterile saline (placebo into the first MPJ. The injections will be performed by an interventional radiologist using fluoroscopy to ensure accurate deposition of the hyaluronan in the joint. Participants will be given the option of a second and final intra-articular injection (of Synvisc® or sterile saline according to the treatment group they are in either 1 or 3 months post-treatment if there is no improvement in pain and the participant has not experienced severe adverse effects after the first injection. The primary outcome measures will be the pain and function subscales of the Foot Health Status Questionnaire. The secondary outcome measures will be pain at the first MPJ (during walking and at rest, stiffness at the first MPJ, passive non-weightbearing dorsiflexion of the first MPJ, plantar flexion strength of the toe-flexors of the hallux, global
Angle-deviation optical profilometer
Chen-Tai Tan; Yuan-Sheng Chan; Zhen-Chin Lin; Ming-Hung Chiu
2011-01-01
@@ We propose a new optical profilometer for three-dimensional (3D) surface profile measurement in real time.The deviation angle is based on geometrical optics and is proportional to the apex angle of a test plate.Measuring the reflectivity of a parallelogram prism allows detection of the deviation angle when the beam is incident at the nearby critical angle. The reflectivity is inversely proportional to the deviation angle and proportional to the apex angle and surface height. We use a charge-coupled device (CCD) camera at the image plane to capture the reflectivity profile and obtain the 3D surface profile directly.%We propose a new optical profilometer for three-dimensional (3D) surface profile measurement in real time.The deviation angle is based on geometrical optics and is proportional to the apex angle of a test plate.Measuring the refiectivity of a parallelogram prism allows detection of the deviation angle when the beam is incident at the nearby critical angle. The refiectivity is inversely proportional to the deviation angle and proportional to the apex angle and surface height. We use a charge-coupled device (CCD) camera at the image plane to capture the refiectivity profile and obtain the 3D surface profile directly.
Heterodyne Interferometer Angle Metrology
Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud
2010-01-01
A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.
Equilibrium contact angle or the most-stable contact angle?
Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A
2014-04-01
It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation.
Mermerkaya MU
2016-12-01
Full Text Available Musa Ugur Mermerkaya,1 Houman Adli2 1Department of Orthopaedics and Traumatology, Medical School, Bozok University, 2Department of Orthopaedics and Traumatology, Yozgat State Hospital, Yozgat, Turkey Purpose: We evaluated the short- to midterm outcomes of metatarsal head-resurfacing hemiarthroplasty and total metatarsophalangeal joint arthroplasty (total joint replacement [TJR] as surgical treatments for advanced-stage hallux rigidus (HR.Patients and methods: From 2012 to 2014, all data from patients who underwent surgery for the treatment of grades 2–3 HR were retrospectively reviewed, and 45 patients were included in this study. Of these patients, 26 underwent metatarsal head-resurfacing hemiarthroplasty (Group I and 19 underwent TJR (Group II. All patients were clinically graded prior to surgery and at their final follow-up visits using the American Orthopedic Foot and Ankle Society’s (AOFAS hallux metatarsophalangeal–interphalangeal scale, a visual analog scale (VAS, and the “first metatarsophalangeal joint range of motion” (MTPJ ROM score.Results: Metatarsal head resurfacing was performed on 26 patients. Two patients underwent bilateral procedures, yielding a total of 28 cases in Group I. TJR was performed on 19 patients in Group II. Of the 26 Group I patients, 12 (46.2% were male and 14 (53.8% were female, with a mean age of 56.3±4.5 years (range: 47–63 years; the mean follow-up duration was 29.9±5.2 months. Of the 19 Group II patients, eight (42.1% were male and eleven (57.9% were female, with a mean age of 57.1±5.8 years (range: 45–66 years; the mean follow-up duration was 27.1±7.5 months. Significant improvements were evident in the AOFAS scores, and the VAS scores decreased, in both groups. No significant difference was evident between groups I and II.Conclusion: After failure of conservative treatment in patients with moderate-to-severe HR, both MTPJ hemiarthroplasty and TJR were associated with effective
Generalization of the Euler Angles
Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis
2002-01-01
It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.
Small angle neutron scattering
Cousin Fabrice
2015-01-01
Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of
Elaine Cristina Martinez Teodoro
2007-01-01
Full Text Available OBJETIVO: Este trabalho teve como objetivo estimar as forças plantares nos dedos dos pés de mulheres com hálux valgo e/ou pés planos. MÉTODOS: Trata-se de um estudo transversal envolvendo mulheres com hálux valgo e/ou pés planos confirmado através de análise radiográfica. Mediram-se as forças plantares, utilizando plataformas de forças. Coletaram-se estas forças com as mulheres descalças e em posição ereta, por três medidas sendo obtida uma média. Os dados foram adquiridos através da ponte amplificadora Spider 8 da HBM e analisados através do programa Catman®. Obtiveram-se as medidas de forças dos dedos de ambos os pés e as médias foram comparadas pelo teste t de Student segundo a presença de hálux valgo e pés planos; a associação entre essas deformidades foi estimada pelo teste exato de Fischer bicaudal, a significância estatística adotada foi alfa = 5%. RESULTADOS: Foram incluídas no estudo, vinte mulheres com presença ou não de hálux valgo. As forças médias encontradas mostraram-se maiores no 5º dedo em relação ao 1º dedo de ambos os pés (pOBJECTIVE: to measure the plantar forces above the toes of women with hallux valgus and/or flat feet. METHODS: This study involved women with hallux valgus and/or flat feet confirmed by X-ray images. The plantar forces were measured utilizing force plates. Force was measured three times, which were taken with the women on barefoot and at upright position, recording the average for the three measurements. Data were acquired from Spider 8 system (HBM and analyzed by using a Catman® software. The measurements for both feet's toes force were reported and the averages were compared by the Student's t-test according to the presence of hallux valgus and flat feet; the association between these deformities was estimated by using the two-tailed Fischer's exact test, the statistical significance adopted was alpha = 5%. RESULTS: For this study, 20 women with or without hallux
Resultados y prospectiva de la investigación podológica en el baile flamenco.
José Manuel Castillo-López
2016-01-01
La expansión mundial y el grado de profesionalización del baile flamenco han equiparado las demandas físicas de esta forma dancística a la de cualquier disciplina deportiva de alto rendimiento. El propio gesto técnico del flamenco, especialmente el zapateado y el impacto que éste genera, es el principal factor predisponentes de lesiones en los pies y miembros inferiores. De estas lesiones, destacan por su alta incidencia el hallux abductus valgus, dedos en garra, juanetes de sastre y onicodis...
余志勇; 温建民; 王林侠; 孙卫东; 蒋云峰; 张帅; 张明敏
2011-01-01
Objective It is to investigate the clinic follow-up compliance of patients with hallux valgus after surgery and puts forwards the corresponding strategies. Methods Through the form of questionnaire, the inquiry scale was filled by telephone interviews. Results 113 effective scales were hacked, there were 83 cases ( 73. 45％ ) with good compliance and 30 cases ( 26.55％ ) with poor compliance. The compliance was not correlated with age, education level, surgical procedure, limbs, hallux valgus severity , but related with residence. Conclusion Patient visits far as the main cause of poor compliance , followed by “ that there is no need to review” . It can be taken corresponding measures to improve compliance and ensure effective operation.%目的 调查拇外翻患者术后门诊随访依从性并提出应对策略.方法 通过问卷调查形式,采用电话访谈方法填写调查量表.结果 收回有效量表113份,其中依从性好83例(73.45%),依从性差30例(26.55%);依从性与患者年龄、文化程度、手术术肢、拇外翻严重程度无相关性,但受居住地影响.结论 患者就诊太远为依从性差的主因,其次为"认为没有必要复查".针对这些人群,可采取相应措施提高依从性,保证术后疗效.
Hysteresis during contact angles measurement.
Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D
2010-03-15
A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle.
Glaister, P.
1997-09-01
Tetrahedral Bond Angle from Elementary Trigonometry The alternative approach of using the scalar (or dot) product of vectors enables the determination of the bond angle in a tetrahedral molecule in a simple way. There is, of course, an even more straightforward derivation suitable for students who are unfamiliar with vectors, or products thereof, but who do know some elementary trigonometry. The starting point is the figure showing triangle OAB. The point O is the center of a cube, and A and B are at opposite corners of a face of that cube in which fits a regular tetrahedron. The required bond angle alpha = AÔB; and using Pythagoras' theorem, AB = 2(square root 2) is the diagonal of a face of the cube. Hence from right-angled triangle OEB, tan(alpha/2) = (square root 2) and therefore alpha = 2tan-1(square root 2) is approx. 109° 28' (see Fig. 1).
Oriented angles in affine space
Włodzimierz Waliszewski
2004-05-01
Full Text Available The concept of a smooth oriented angle in an arbitrary affine space is introduced. This concept is based on a kinematics concept of a run. Also, a concept of an oriented angle in such a space is considered. Next, it is shown that the adequacy of these concepts holds if and only if the affine space, in question, is of dimension 2 or 1.
The Semiotic and Conceptual Genesis of Angle
Tanguay, Denis; Venant, Fabienne
2016-01-01
In the present study, we try to understand how students at the end of primary school conceive of angle: Is an angle a magnitude for them or a geometric figure, and how do they manage to coordinate the two aspects in their understanding of the concepts of angle and of angle measurement? With the aim of better grasping the way "angle" is…
Frequency scaling for angle gathers
Zuberi, M. A H
2014-01-01
Angle gathers provide an extra dimension to analyze the velocity after migration. Space-shift and time shift-imaging conditions are two methods used to obtain angle gathers, but both are reasonably expensive. By scaling the time-lag axis of the time-shifted images, the computational cost of the time shift imaging condition can be considerably reduced. In imaging and more so Full waveform inversion, frequencydomain Helmholtz solvers are used more often to solve for the wavefields than conventional time domain extrapolators. In such cases, we do not need to extend the image, instead we scale the frequency axis of the frequency domain image to obtain the angle gathers more efficiently. Application on synthetic data demonstrate such features.
Angle independent velocity spectrum determination
2014-01-01
An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral vel...... velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes....
Scaling of misorientation angle distributions
Hughes, D.A.; Chrzan, D.C.; Liu, Q.
1998-01-01
The measurement of misorientation angle distributions following different amounts of deformation in cold-rolled aluminum and nickel and compressed stainless steel is reported. The sealing of the dislocation cell boundary misorientation angle distributions is studied. Surprisingly, the distributions...... for the small to large strain regimes for aluminum, 304L stainless steel, nickel, and copper (taken from the literature )appear to be identical. Hence the distributions may be "universal." These results have significant implications for the development of dislocation based deformation models. [S0031...
Systematic variations in divergence angle
Okabe, Takuya
2012-01-01
Practical methods for quantitative analysis of radial and angular coordinates of leafy organs of vascular plants are presented and applied to published phyllotactic patterns of various real systems from young leaves on a shoot tip to florets on a flower head. The constancy of divergence angle is borne out with accuracy of less than a degree. It is shown that apparent fluctuations in divergence angle are in large part systematic variations caused by the invalid assumption of a fixed center and/or by secondary deformations, while random fluctuations are of minor importance.
Mermerkaya, Musa Ugur; Adli, Houman
2016-01-01
Purpose We evaluated the short- to midterm outcomes of metatarsal head-resurfacing hemiarthroplasty and total metatarsophalangeal joint arthroplasty (total joint replacement [TJR]) as surgical treatments for advanced-stage hallux rigidus (HR). Patients and methods From 2012 to 2014, all data from patients who underwent surgery for the treatment of grades 2–3 HR were retrospectively reviewed, and 45 patients were included in this study. Of these patients, 26 underwent metatarsal head-resurfacing hemiarthroplasty (Group I) and 19 underwent TJR (Group II). All patients were clinically graded prior to surgery and at their final follow-up visits using the American Orthopedic Foot and Ankle Society’s (AOFAS) hallux metatarsophalangeal–interphalangeal scale, a visual analog scale (VAS), and the “first metatarsophalangeal joint range of motion” (MTPJ ROM) score. Results Metatarsal head resurfacing was performed on 26 patients. Two patients underwent bilateral procedures, yielding a total of 28 cases in Group I. TJR was performed on 19 patients in Group II. Of the 26 Group I patients, 12 (46.2%) were male and 14 (53.8%) were female, with a mean age of 56.3±4.5 years (range: 47–63 years); the mean follow-up duration was 29.9±5.2 months. Of the 19 Group II patients, eight (42.1%) were male and eleven (57.9%) were female, with a mean age of 57.1±5.8 years (range: 45–66 years); the mean follow-up duration was 27.1±7.5 months. Significant improvements were evident in the AOFAS scores, and the VAS scores decreased, in both groups. No significant difference was evident between groups I and II. Conclusion After failure of conservative treatment in patients with moderate-to-severe HR, both MTPJ hemiarthroplasty and TJR were associated with effective recovery of toe function and MTPJ ROM, as well as good short- to midterm functional outcomes. PMID:28008240
Contactless angle detection using permalloy
Eijkel, Kees J.; Rijk, Rolf
1988-01-01
An overview is given of measurements on angle detectors. The detectors consist of a pair of planar-Hall elements opposite to a rotatable magnet. The measurements are performed on a number of planar-Hall elements of different shape and size, and show good agreement with a previously described theoret
Effects of slant angle and illumination angle on MTF estimations
Vhengani, LM
2012-07-01
Full Text Available .085 0.09 0.095 K:\\Working Folder\\Project_On_orbit MTF\\edgetargets\\MTF_Lab_Measurements _20120302_Edge Slant Angle (degrees) Ny qu ist MT F (c yc le/p ixe l) Data Regression -18 -16 -14 -12 -10 -8 -6 -4 -2 0.05 0.055 0.06 0....065 0.07 0.075 0.08 0.085 0.09 K:\\Working Folder\\Project_On_orbit MTF\\edgetargets\\MTF_Lab_Measurements_20120303_Edge Slant Angle (degrees) Ny qu ist MT F (c yc le/p ixe l) Data Regression Figure 6. Regression of positive slant...
An Angle Criterion for Riesz Bases
Lindner, Alexander M; Bittner, B.
1999-01-01
We present a characterization of Riesz bases in terms ofthe angles between certain finite dimensional subspaces. Correlationsbetween the bounds of the Riesz basis and the size of the angles arederived.......We present a characterization of Riesz bases in terms ofthe angles between certain finite dimensional subspaces. Correlationsbetween the bounds of the Riesz basis and the size of the angles arederived....
Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Sillesen, Henrik
1998-01-01
to conventional B-mode imaging MACI offers better defined tissue boundaries and lower variance of the speckle pattern, resulting in an image with reduced random variations. Design and implementation of a compound imaging system is described, images of rubber tubes and porcine aorta are shown and effects......This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared...... on visualization are discussed. The speckle reduction is analyzed numerically and the results are found to be in excellent agreement with existing theory. An investigation of detectability of low-contrast lesions shows significant improvements compared to conventional imaging. Finally, possibilities for improving...
Optimisation of Fan Blade Angle
Swaroop M P
2017-01-01
Full Text Available This report represents the optimization of fan blade angle in accordance with the various room temperatures that can be in the tropical area like India. We took this work mainly because cooling is an important factor now a days in every area where construction and rooms are there and ceiling fans are the most common device that is commonly used. So it is of utmost importance to tweak the performance of this ceiling fan so that it can function in its most optimal condition. We have modeled the fan in a modeling software (SOLIDWORKS and imported that into an analyzing software (ANSYS and a result is generated on the various blade angles (0, 4, 8 and 12.5 degrees in accordance to room conditions. A trend line curve with the obtained data is expected as the result which can be crucial for designing of future fans
Nucleation of small angle boundaries
Nabarro, FRN
1996-12-01
Full Text Available -ANGLE BOUNDARIES F.R.N. Nabarro Condensed Matter Physics Research Unit, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, and Division of Materials Science and Technology, CSIR, P.O. Box 395, Pretoria, South... with eq. 11. Acknowledgment F.R.N. Nabarro is grateful to the University of Virginia for hospitality during the course of this work. D. Kuhlmann-Wilsdorf thanks the National Science Foundation, (Surface Engineering...
LHC Report: playing with angles
Mike Lamont for the LHC team
2016-01-01
Ready (after a machine development period), steady (running), go (for a special run)! The crossing angles are an essential feature of the machine set-up. They have to be big enough to reduce the long-range beam-beam effect. The LHC has recently enjoyed a period of steady running and managed to set a new record for “Maximum Stable Luminosity Delivered in 7 days” of 3.29 fb-1 between 29 August and 4 September. The number of bunches per beam remains pegged at 2220 because of the limitations imposed by the SPS beam dump. The bunch population is also somewhat reduced due to outgassing near one of the injection kickers at point 8. Both limitations will be addressed during the year-end technical stop, opening the way for increased performance in 2017. On 10 and 11 September, a two day machine development (MD) period took place. The MD programme included a look at the possibility of reducing the crossing angle at the high-luminosity interaction points. The crossing angles are an ess...
Small angle scattering and polymers
Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)
1996-12-31
The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.
Theta angle in holographic QCD
Jarvinen, Matti
2016-01-01
V-QCD is a class of effective holographic models for QCD which fully includes the backreaction of quarks to gluon dynamics. The physics of the theta-angle and the axial anomaly can be consistently included in these models. We analyze their phase diagrams over ranges of values of the quark mass, N_f/N_c, and theta, computing observables such as the topological susceptibility and the meson masses. At small quark mass, where effective chiral Lagrangians are reliable, they agree with the predictions of V-QCD.
Device for Measuring Landslide Critical Angle
Li Xueling; Xia Weisheng; Huang Daoyou; Yu Yun
2016-01-01
The mountain landslide has high destructive effects, discussion of its landslide critical angle has always been one of the major concerns, and we designed a system that can automatically measure the landslide critical angle. This equipment consists of the
30 CFR 56.19037 - Fleet angles.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fleet angles. 56.19037 Section 56.19037 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Sheaves § 56.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979, shall not...
30 CFR 57.19037 - Fleet angles.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fleet angles. 57.19037 Section 57.19037 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Sheaves § 57.19037 Fleet angles. Fleet angles on hoists installed after November 15, 1979, shall not...
Helencar Ignácio
2006-01-01
Full Text Available Os autores avaliaram 33 pacientes (48 pés com hálux valgo moderado a grave tratados cirurgicamente com a técnica de osteotomia de base do I metatarso em cunha de adição associada a reparação de tecidos moles. Comparações correlacionando sexo, idade e parâmetros radiográficos, foram feitas pelo teste t para amostras independentes; o desvio do sesamóide foi comparado pelo teste não paramétrico de Kruskal-Wallis. Todos os pacientes responderam a um questionário no qual expressaram o grau de satisfação com o resultado final da cirurgia. 76% dos pacientes eram do sexo feminino, com idade entre 14 e 60 anos (média de 38,15 anos, com tempo médio de seguimento de 41 meses. Em relação ao sexo não houve diferença na variação radiográfica. Também não foram constatadas diferenças no pré e pós-operatório quando comparado os valores médios dos pés direito e esquerdo. A avaliação radiológica apresentou 73% de resultados excelentes e o grau de satisfação total foi de 60,7% . Não há evidência da idade média influenciar no grau de satisfação, porém acima de 60 anos todos os pacientes relataram satisfação parcial. Concluímos que o procedimento cirúrgico apresentado seja um método seguro e eficaz para o tratamento do halux valgo moderado e grave.The authors evaluated 33 patients (48 feet with moderate to severe hallux valgus, surgically treated by using a 1st metatarsal wedged base osteotomy technique associated to soft tissues repair. Comparisons correlating gender, age, and x-ray parameters were performed by using the t-test for independent samples; sesamoid deviation was compared by Kruskal-Wallis non-parametric test. All patients answered to a questionnaire in which they expressed their degree of satisfaction regarding the final results of the surgery. Seventy six per cent of patients were women between 14 and 60 years old (average 38.15 years old with an average follow-up time of 41 months. There was no
Hahn, Thomas; Foldspang, Anders
1997-01-01
Quadriceps muscle contraction tends to straighten the Q angle. We expected that sports comprising a high amount of quadriceps training could be associated with low Q angles. The aim of the present study was to estimate the Q angle in athletes and to investigate its potential associations with par......Quadriceps muscle contraction tends to straighten the Q angle. We expected that sports comprising a high amount of quadriceps training could be associated with low Q angles. The aim of the present study was to estimate the Q angle in athletes and to investigate its potential associations...... with participation in sport. Three hundred and thirty-nine athletes had their Q angle measured. The mean of right-side Q angles was higher than left side, and the mean Q angle was higher in women than in men. The Q angle was positively associated with years of jogging, and negatively with years of soccer, swimming...... and sports participation at all. It is concluded that the use of Q angle measurements is questionable....
Individualized optimal release angles in discus throwing.
Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing
2010-02-10
The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques.
Wafer scale oblique angle plasma etching
Burckel, David Bruce; Jarecki, Jr., Robert L.; Finnegan, Patrick Sean
2017-05-23
Wafer scale oblique angle etching of a semiconductor substrate is performed in a conventional plasma etch chamber by using a fixture that supports a multiple number of separate Faraday cages. Each cage is formed to include an angled grid surface and is positioned such that it will be positioned over a separate one of the die locations on the wafer surface when the fixture is placed over the wafer. The presence of the Faraday cages influences the local electric field surrounding each wafer die, re-shaping the local field to be disposed in alignment with the angled grid surface. The re-shaped plasma causes the reactive ions to follow a linear trajectory through the plasma sheath and angled grid surface, ultimately impinging the wafer surface at an angle. The selected geometry of the Faraday cage angled grid surface thus determines the angle at with the reactive ions will impinge the wafer.
Transcription and the Pitch Angle of DNA
Olsen, Kasper W
2013-01-01
The question of the value of the pitch angle of DNA is visited from the perspective of a geometrical analysis of transcription. It is suggested that for transcription to be possible, the pitch angle of B-DNA must be smaller than the angle of zero-twist. At the zero-twist angle the double helix is maximally rotated and its strain-twist coupling vanishes. A numerical estimate of the pitch angle for B-DNA based on differential geometry is compared with numbers obtained from existing empirical data. The crystallographic studies shows that the pitch angle is approximately 38 deg., less than the corresponding zero-twist angle of 41.8 deg., which is consistent with the suggested principle for transcription.
Meningiomas of the cerebellopontine angle.
Matthies, C; Carvalho, G; Tatagiba, M; Lima, M; Samii, M
1996-01-01
Meningiomas of the cerebellopontine angle (CPA) represent a clinically and surgically interesting entity. The opportunity of complete surgical excision and the incidence of impairment of nerval structures largely depend on the tumour biology that either leads to displacement of surrounding structures by an expansive type of growth or to an enveloping of nerval and vascular structures by an en plaque type of growth. As the origin and the direction of growth are very variable, the exact tumour extension in relation to the nerval structures and the tumour origin can be identified sometimes only at the time of surgery. Out of a series of 230 meningiomas of the posterior skull base operated between 1978 and 1993, data of 134 meningiomas involving the cerebellopontine angle are presented. There were 20% male and 80% female patients, age at the time of surgery ranging from 18 to 76 years, on the average 51 years. The clinical presentation was characterized by a predominant disturbance of the cranial nerves V (19%), VII (11%), VIII (67%) and the caudal cranial nerves (6%) and signs of ataxia (28%). 80% of the meningiomas were larger than 30 mm in diameter, 53% led to evident brainstem compression or dislocation and 85% extended anteriorly to the internal auditory canal. Using the lateral suboccipital approach in the majority of cases and a combined presigmoidal or combined suboccipital and subtemporal approaches in either sequence in 5%, complete tumour removal (Simpson I and II) was accomplished in 95% and subtotal tumour removal in 5%. Histologically the meningiotheliomatous type was most common (49%) followed by the mixed type (19%), fibroblastic (16%), psammomatous (7%), hemangioblastic (7%) and anaplastic (2%) types. Major post-operative complications were CSF leakage (8%) requiring surgical revision in 2% and hemorrhage (3%) requiring revision in 2%. While the majority of neurological disturbances showed signs of recovery, facial nerve paresis or paralysis was
Dynamic contact angle measurements on superhydrophobic surfaces
Kim, Jeong-Hyun; Kavehpour, H. Pirouz; Rothstein, Jonathan P.
2015-03-01
In this paper, the dynamic advancing and receding contact angles of a series of aqueous solutions were measured on a number of hydrophobic and superhydrophobic surfaces using a modified Wilhelmy plate technique. Superhydrophobic surfaces are hydrophobic surfaces with micron or nanometer sized surface roughness. These surfaces have very large static advancing contact angles and little static contact angle hysteresis. In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth hydrophobic Teflon surface were found to obey the scaling with capillary number predicted by the Cox-Voinov-Tanner law, θD3 ∝ Ca. The response of the dynamic contact angle on the superhydrophobic surfaces, however, did not follow the same scaling law. The advancing contact angle was found to remain constant at θA = 160∘, independent of capillary number. The dynamic receding contact angle measurements on superhydrophobic surfaces were found to decrease with increasing capillary number; however, the presence of slip on the superhydrophobic surface was found to result in a shift in the onset of dynamic contact angle variation to larger capillary numbers. In addition, a much weaker dependence of the dynamic contact angle on capillary number was observed for some of the superhydrophobic surfaces tested.
Caustic graphene plasmons with Kelvin angle
Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile
2015-01-01
A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.
A thermodynamic model of contact angle hysteresis
Makkonen, Lasse
2017-08-01
When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.
Contact angle measurements under thermodynamic equilibrium conditions.
Lages, Carol; Méndez, Eduardo
2007-08-01
The precise control of the ambient humidity during contact angle measurements is needed to obtain stable and valid data. For a such purpose, a simple low-cost device was designed, and several modified surfaces relevant to biosensor design were studied. Static contact angle values for these surfaces are lower than advancing contact angles published for ambient conditions, indicating that thermodynamic equilibrium conditions are needed to avoid drop evaporation during the measurements.
高战鳌; 张云; 赵思桥; 马顺前
2016-01-01
目的：分析微创截骨矫形后绷带外固定拇外翻治疗的效果。方法对519例(961足)拇外翻患者微创截骨矫形术后采用“8”字绷带缠绕外固定。结果患者均获得随访，时间3~36个月。截骨均愈合，时间为12~20周。无骨折不愈合或假关节形成者。结论绷带外固定可以达到维持复位后的固定要求，使骨折愈合；与传统固定方法比较该方法具有方便、灵活、痛苦小且可早期功能锻炼等优点，值得在一些特殊部位骨折固定中应用。%Objective To analyze the efficacy of the external bandage fixation for corrective osteotomy surgery of hal-lux valgus. Methods All the 519 patients (961 feet) were carried out minimally invasive corrective osteotomy sur-gery, twining the incision with bandage as “8” shape for external fixation. Results All the patients had been fol-lowed-up from 3 months to 36 months and the fracture were healed within the time of 12~20 weeks, no fracture non-union or pseudoarthrosis was found. Conclusions The way of external bandage fixation can meet the requirements of maintaining restoration, make the fracture heal up. Comparing with the traditional way of fixation, the advantages of convenience, agility, less pain and early functional exercises are obvious in this way, so it′s worth to popularize and apply in fracture fixation of some special body parts.
Contact angle hysteresis on fluoropolymer surfaces.
Tavana, H; Jehnichen, D; Grundke, K; Hair, M L; Neumann, A W
2007-10-31
Contact angle hysteresis of liquids with different molecular and geometrical properties on high quality films of four fluoropolymers was studied. A number of different causes are identified for hysteresis. With n-alkanes as probe liquids, contact angle hysteresis is found to be strongly related to the configuration of polymer chains. The largest hysteresis is obtained with amorphous polymers whereas the smallest hysteresis occurs for polymers with ordered molecular chains. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Correlation of contact angle hysteresis with the size of n-alkane molecules supports this conclusion. On the films of two amorphous fluoropolymers with different molecular configurations, contact angle hysteresis of one and the same liquid with "bulky" molecules is shown to be quite different. On the surfaces of Teflon AF 1600, with stiff molecular chains, the receding angles of the probe liquids are independent of contact time between solid and liquid and similar hysteresis is obtained for all the liquids. Retention of liquid molecules on the solid surface is proposed as the most likely cause of hysteresis in these systems. On the other hand, with EGC-1700 films that consist of flexible chains, the receding angles are strongly time-dependent and the hysteresis is large. Contact angle hysteresis increases even further when liquids with strong dipolar intermolecular forces are used. In this case, major reorganization of EGC-1700 chains due to contact with the test liquids is suggested as the cause. The effect of rate of motion of the three-phase line on the advancing and receding contact angles, and therefore contact angle hysteresis, is investigated. For low viscous liquids, contact angles are independent of the drop front velocity up to approximately 10 mm/min. This agrees with the results of an earlier study that showed that the rate-dependence of the contact angles is an issue only
Automatic cobb angle determination from radiographic images
Sardjono, Tri Arief; Wilkinson, Michael H.F.; Veldhuizen, Albert G.; Ooijen, van Peter M.A.; Purnama, Ketut E.; Verkerke, Gijsbertus J.
2013-01-01
Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Met
Automatic Cobb Angle Determination From Radiographic Images
Sardjono, Tri Arief; Wilkinson, Michael H. F.; Veldhuizen, Albert G.; van Ooijen, Peter M. A.; Purnama, Ketut E.; Verkerke, Gijsbertus J.
2013-01-01
Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Methods.
Does gallbladder angle affect gallstone formation?
Sanal, Bekir; Korkmaz, Mehmet; Zeren, Sezgin; Can, Fatma; Elmali, Ferhan; Bayhan, Zulfu
2016-01-01
Morphology of gallbladder varies considerably from person to person. We believe that one of the morphological variations of gallbladder is the "gallbladder angle". Gallbladder varies also in "angle", which, to the best of our knowledge, has never been investigated before. The purpose of this study was to investigate the impact of gallbladder angle on gallstone formation. in this study, 1075 abdominal computed tomography (CT) images were retrospectively examined. Patients with completely normal gallbladders were selected. Among these patients, those with both abdominal ultrasound and blood tests were identified in the hospital records and included in the study. Based on the findings of the ultrasound scans, patients were divided into two groups as patients with gallstones and patients without gallstones. Following the measurement of gallbladder angles on the CT images, the groups were statistically evaluated. The gallbladder angle was smaller in patients with gallstones (49 ± 21 degrees and 53 ± 19 degrees) and the gallbladder with larger angle was 1.015 (1/0.985) times lower the risk of gallstone formation. However, these were not statistically significant (p>0,05). A more vertically positioned gallbladder does not affect gallstone formation. However, a smaller gallbladder angle may facilitate gallstone formation in patients with the risk factors. Gallstones perhaps more easily and earlier develop in gallbladders with a smaller angle.
Automatic cobb angle determination from radiographic images
Sardjono, Tri Arief; Wilkinson, Michael H.F.; Veldhuizen, Albert G.; van Ooijen, Peter M.A.; Purnama, Ketut E.; Verkerke, Gijsbertus Jacob
2013-01-01
Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Methods.
Acute angle closure glaucoma following ileostomy surgery
Mariana Meirelles Lopes
2015-02-01
Full Text Available Angle-closure glaucoma can be induced by drugs that may cause pupillary dilatation. We report a case of a patient that developed bilateral angle closure glaucoma after an ileostomy surgery because of systemic atropine injection. This case report highlights the importance of a fast ophthalmologic evaluation in diseases with ocular involvement in order to make accurate diagnoses and appropriate treatments.
Apparent contact angle and contact angle hysteresis on liquid infused surfaces
Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim
We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as `weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.
Apparent contact angle and contact angle hysteresis on liquid infused surfaces.
Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim
2016-12-21
We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as 'weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.
Solid angles III. The role of conformers in solid angle calculations
White, D
1995-06-14
Full Text Available The values of the solid angles Omega for a range of commonly encountered ligands in organometallic chemistry (phosphines, phosphites, amines, arsines and cyclopentadienyl rings) have been determined. The solid angles were derived from a single...
Reliable measurement of the receding contact angle.
Korhonen, Juuso T; Huhtamäki, Tommi; Ikkala, Olli; Ras, Robin H A
2013-03-26
Surface wettability is usually evaluated by the contact angle between the perimeter of a water drop and the surface. However, this single measurement is not enough for proper characterization, and the so-called advancing and receding contact angles also need to be measured. Measuring the receding contact angle can be challenging, especially for extremely hydrophobic surfaces. We demonstrate a reliable procedure by using the common needle-in-the-sessile-drop method. Generally, the contact line movement needs to be followed, and true receding movement has to be distinguished from "pseudo-movement" occurring before the receding angle is reached. Depending on the contact angle hysteresis, the initial size of the drop may need to be surprisingly large to achieve a reliable result. Although our motivation for this work was the characterization of superhydrophobic surfaces, we also show that this method works universally ranging from hydrophilic to superhydrophobic surfaces.
Development of Tibiofemoral Angle in Korean Children
Yoo, Jae Ho; Cho, Tae-Joon; Chung, Chin Youb; Yoo, Won Joon
2008-01-01
This study was performed to identify the chronological changes of the knee angle or the tibiofemoral angles in normal healthy Korean children. Full-length anteroposterior view standing radiographs of 818 limbs of 452 Korean children were analyzed. The overall patterns of the chronological changes in the knee angle were similar to those described previously in western or Asian children, but the knee angle development was delayed, i.e., genu varum before 1 yr, neutral at 1.5 yr, increasing genu valgum with maximum a value of 7.8° at 4 yr, followed by a gradual decrease to approximately 5-6° of genu valgum of the adult level at 7 to 8 yr of age. These normative data on chronological changes of knee angles should be taken into consideration when evaluating lower limb alignment in children. PMID:18756063
Nanodrop contact angles from molecular dynamics simulations
Ravipati, Srikanth; Aymard, Benjamin; Yatsyshin, Petr; Galindo, Amparo; Kalliadasis, Serafim
2016-11-01
The contact angle between three phases being in thermodynamic equilibrium is highly sensitive to the nature of the intermolecular forces as well as to various fluctuation effects. Determining the Young contact angle of a sessile drop sitting on a substrate from molecular dynamics (MD) simulations is a highly non-trivial task. Most commonly employed methods for finding droplet contact angles from MD simulation data either require large numbers of particles or are system-dependent. We propose a systematic geometry based methodology for extracting the contact angle from simulated sessile droplets by analysing an appropriately coarse-grained density field. To demonstrate the method, we consider Lennard-Jones (LJ) and SPC/E water nanodroplets of different sizes sitting on planar LJ walls. Our results are in good agreement with Young contact angle values computed employing test-area perturbation method.
Apparent contact angle and contact angle hysteresis on liquid infused surfaces
Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim
2017-01-01
We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small b...
Contact angle hysteresis of microbead suspensions.
Waghmare, Prashant R; Mitra, Sushanta K
2010-11-16
Microbead suspensions are often used in microfluidic devices for transporting biomolecules. An experimental investigation on the wettability of microbead suspension is presented in this study. The variation in the surface tension and the equilibrium contact angle with the change in the volume fraction of the microbead is presented here. The surface tension of the microbead suspension is measured with the pendant drop technique, whereas the dynamic contact angle measurements, i.e., advancing and receding contact angles, are measured with the sessile drop technique. An equilibrium contact angle of a suspension with particular volume fraction is determined by computing an average over the measured advancing and receding contact angles. It is observed that the surface tension and the equilibrium contact angle determined from advancing and receding contact angles vary with the magnitude of the microbeads volume fraction in the suspension. A decrease in the surface tension with an increase in the volume fraction of the microbead suspension is observed. The advancement and the recession in contact line for dynamic contact angle measurements are achieved with the motorized dosing mechanism. For microbead suspensions, the advancement of the contact line is faster as compared to the recession of the contact line for the same flow rate. The presence of microbeads assists in the advancement and the recession of the contact line of the suspension. A decrease in the equilibrium contact angles with an increase in the microbead suspension volume fraction is observed. Inclusion of microbeads in the suspension increases the wetting capability for the considered combination of the microbead suspension and substrate. Finally, empirical correlations for the surface tension and the contact angle of the suspension as a function of microbead volume fraction are proposed. Such correlations can readily be used to develop mechanistic models for the capillary transport of microbead
林涧; 梁成; 郑和平; 陆骅; 张天浩; 王之江; 万华俊
2015-01-01
目的 报道(足母)趾胫侧底动脉蒂足内侧缘静脉营养血管皮瓣的临床应用效果.方法 根据跨趾胫侧底动脉与足内侧缘静脉营养血管间吻合关系,以第1跖趾关节近端(2.2±0.7) cm 处的(足母)趾胫侧底动脉穿出点为旋转点,以旋转点与内踝尖之间足内侧缘静脉走向为轴心线,设计(足母)趾胫侧底动脉蒂足内侧缘静脉营养血管皮瓣,转位修复(足母)趾皮肤软组织缺损.结果 临床应用共5例,皮瓣均成活,创面一期愈合,经1～12个月随访,皮瓣质地优良、色泽接近正常,外形美观.结论 (足母)趾胫侧底动脉蒂足内侧缘静脉营养血管皮瓣可转位修复跨趾皮肤软组织缺损.%Objective To introduce the clinical application of venous nutrition flap pedicled by medial plantar artery of the hallux on the medical aspect of the foot.Methods Based on the anastomoses between the medial plantar artery of the hallux and the nutritional vein,the flap was designed with the perforator of medial plantar artery adjacent to the first metatarsal bone as the rotation point.The flap axis was along the vein at the medial aspect of the foot between rotation point and medial malleolus.Results 5 cases were treated with primary healing and complete survival flaps.The patients were followed up for 1-12 months with good match of texture and color.Conclusions The venous nutrition flap pedicled by medial plantar artery of the hallux on the medical aspect of the foot can be transpositioned to repair the defect at forefoot.
Globographic visualisation of three dimensional joint angles.
Baker, Richard
2011-07-07
Three different methods for describing three dimensional joint angles are commonly used in biomechanics. The joint coordinate system and Cardan/Euler angles are conceptually quite different but are known to represent the same underlying mathematics. More recently the globographic method has been suggested as an alternative and this has proved particularly attractive for the shoulder joint. All three methods can be implemented in a number of ways leading to a choice of angle definitions. Very recently Rab has demonstrated that the globographic method is equivalent to one implementation of the joint coordinate system. This paper presents a rigorous analysis of the three different methods and proves their mathematical equivalence. The well known sequence dependence of Cardan/Euler is presented as equivalent to configuration dependence of the joint coordinate system and orientation dependence of globographic angles. The precise definition of different angle sets can be easily visualised using the globographic method using analogues of longitude, latitude and surface bearings with which most users will already be familiar. The method implicitly requires one axis of the moving segment to be identified as its principal axis and this can be extremely useful in helping define the most appropriate angle set to describe the orientation of any particular joint. Using this technique different angle sets are considered to be most appropriate for different joints and examples of this for the hip, knee, ankle, pelvis and axial skeleton are outlined.
Contact angle hysteresis, adhesion, and marine biofouling.
Schmidt, Donald L; Brady, Robert F; Lam, Karen; Schmidt, Dale C; Chaudhury, Manoj K
2004-03-30
Adhesive and marine biofouling release properties of coatings containing surface-oriented perfluoroalkyl groups were investigated. These coatings were prepared by cross-linking a copolymer of 1H,1H,2H,2H-heptadecafluorodecyl acrylate and acrylic acid with a copolymer of poly(2-isopropenyl-2-oxazoline) and methyl methacrylate at different molar ratios. The relationships between contact angle, contact angle hysteresis, adhesion, and marine biofouling were studied. Adhesion was determined by peel tests using pressure-sensitive adhesives. The chemical nature of the surfaces was studied by using X-ray photoelectron spectroscopy. Resistance to marine biofouling of an optimized coating was studied by immersion in seawater and compared to previous, less optimized coatings. The adhesive release properties of the coatings did not correlate well with the surface energies of the coatings estimated from the static and advancing contact angles nor with the amount of fluorine present on the surface. The adhesive properties of the surfaces, however, show a correlation with water receding contact angles and contact angle hysteresis (or wetting hysteresis) resulting from surface penetration and surface reconstruction. Coatings having the best release properties had both the highest cross-link density and the lowest contact angle hysteresis. An optimized coating exhibited unprecedented resistance to marine biofouling. Water contact angle hysteresis appears to correlate with marine biofouling resistance.
Wide-angle vision for road views
Huang, F.; Fehrs, K.-K.; Hartmann, G.; Klette, R.
2013-03-01
The field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.
Bite Angle Effects in Hydroformylation Catalysis
van LEEUWEN
2001-01-01
Recent advances in rhodium catalyzed hydroformylation using xanthene-based ligands will be reviewed.The calculated natural bite angles of the ligands discussed are in the range 100-123℃ While the general trend is clear-higher 1:b ratios at wider angles, small changes in the bite angle do not exhibit a regular effect on the selectivity of the reaction.The same is true for the rate of CO dissociation;the larger the rate of the CO dissociation, the larger the rate of hydroformylation, but for small changes the effects do not comply with this rule.
Rajjoub LZ
2014-07-01
Full Text Available Lamise Z Rajjoub, Nisha Chadha, David A Belyea Department of Ophthalmology, The George Washington University, Washington, DC, USA Abstract: This is a case report describing recurrent intermittent acute angle closure episodes in the setting of topiramate use in a female suffering from migraines. Despite laser peripheral iridotomy placement for the pupillary block component, and the discontinuation of topiramate, the acute angle closure did not resolve in the left eye with chronic angle closure and the patient required urgent trabeculectomy. The right eye responded to laser peripheral iridotomy immediately and further improved after the cessation of topiramate. While secondary angle closure glaucoma due to topiramate use has been widely reported, its effects in patients with underlying primary angle closure glaucoma have not been discussed. Our report highlights the importance of recognizing the often multifactorial etiology of angle closure glaucoma to help guide clinical management. Keywords: angle closure glaucoma, plateau iris, topiramate, secondary glaucoma, drug-induced glaucoma
EMERGENCE ANGLE OF FLOW OVER AN AERATOR
无
2007-01-01
Aerator is an important device for release works of hydraulic structures with high-speed flow in order to protect them from cavitation damage. This kind of protecting effect is related closely to cavity length below the aerator, while the cavity length is dominated by the emergence angle over the aerator. Therefore it is crucial to determine this angle accurately. In the present paper the affecting intensities of flow depth and the fluctuating velocity on this angle were analyzed through two introduced parameters. Furthermore, the improved expressions of emergence angle estimation, for both ramp-type and step-type aerators, were presented by means of 68 sets of experimental data from 6 projects based on error theory. The results showed that the present method has higher accuracy than the previously reported methods.
Nanofluid surface wettability through asymptotic contact angle.
Vafaei, Saeid; Wen, Dongsheng; Borca-Tasciuc, Theodorian
2011-03-15
This investigation introduces the asymptotic contact angle as a criterion to quantify the surface wettability of nanofluids and determines the variation of solid surface tensions with nanofluid concentration and nanoparticle size. The asymptotic contact angle, which is only a function of gas-liquid-solid physical properties, is independent of droplet size for ideal surfaces and can be obtained by equating the normal component of interfacial force on an axisymmetric droplet to that of a spherical droplet. The technique is illustrated for a series of bismuth telluride nanofluids where the variation of surface wettability is measured and evaluated by asymptotic contact angles as a function of nanoparticle size, concentration, and substrate material. It is found that the variation of nanofluid concentration, nanoparticle size, and substrate modifies both the gas-liquid and solid surface tensions, which consequently affects the force balance at the triple line, the contact angle, and surface wettability.
Haematological Parameters in Open Angle Glaucoma Patients ...
GA Akinlabi, VI Iyawe. Abstract. There is potential for blood related factors to affect aqueous production or optic nerve functions. ... Here we compare hematological parameters for a group of 68 chronic open-angle glaucoma (OAG) patients and ...
Contact angle hysteresis on superhydrophobic stripes.
Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I
2014-08-21
We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.
A microscopic view on contact angle selection
Snoeijer, Jacco H.; Andreotti, Bruno
2008-01-01
We discuss the equilibrium condition for a liquid that partially wets a solid on the level of intermolecular forces. Using a mean field continuum description, we generalize the capillary pressure from variation of the free energy and show at what length scale the equilibrium contact angle is selected. After recovering Young's law for homogeneous substrates, it is shown how hysteresis of the contact angle can be incorporated in a self-consistent fashion. In all cases the liquid-vapor interface...
Pressure dependence of the contact angle.
Wu, Jiyu; Farouk, T; Ward, C A
2007-06-07
When a liquid and its vapor contact a smooth, homogeneous surface, Gibbsian thermodynamics indicates that the contact angle depends on the pressure at the three-phase line of an isothermal system. When a recently proposed adsorption isotherm for a solid-vapor interface is combined with the equilibrium conditions and the system is assumed to be in a cylinder where the liquid-vapor interface can be approximated as spherical, the contact-angle-pressure relation can be made explicit. It indicates that a range of contact angles can be observed on a smooth homogeneous surface by changing the pressure at the three-phase line, but it also indicates that the adsorption at the solid-liquid interface is negative, and leads to the prediction that the contact angle increases with pressure. The predicted dependence of the contact angle on pressure is investigated experimentally in a system that has an independent mechanism for determining when thermodynamic equilibrium is reached. The predictions are in agreement with the measurements. The results provide a possible explanation for contact angle hysteresis.
Winding angles of long lattice walks
Hammer, Yosi; Kantor, Yacov
2016-07-01
We study the winding angles of random and self-avoiding walks (SAWs) on square and cubic lattices with number of steps N ranging up to 107. We show that the mean square winding angle of random walks converges to the theoretical form when N → ∞. For self-avoiding walks on the square lattice, we show that the ratio /2 converges slowly to the Gaussian value 3. For self-avoiding walks on the cubic lattice, we find that the ratio /2 exhibits non-monotonic dependence on N and reaches a maximum of 3.73(1) for N ≈ 104. We show that to a good approximation, the square winding angle of a self-avoiding walk on the cubic lattice can be obtained from the summation of the square change in the winding angles of lnN independent segments of the walk, where the ith segment contains 2i steps. We find that the square winding angle of the ith segment increases approximately as i0.5, which leads to an increase of the total square winding angle proportional to (lnN)1.5.
Hennig, A; Eichhorn, K-J; Staudinger, U; Sahre, K; Rogalli, M; Stamm, M; Neumann, A W; Grundke, K
2004-08-03
The phenomenon of contact angle hysteresis was studied on smooth films of polyimide, a polymer type used in the microelectronic industry, by dynamic cycling contact angle measurements based on axisymmetric drop shape analysis-profile in combination with variable angle spectroscopic ellipsometry (VASE). It was found that both advancing and receding contact angles became smaller with increasing the number of cycles and are, therefore, not a property of the dry solid alone. The changes of the wetting behavior during these dynamic cycling contact angle measurements are attributed mainly to swelling and/or liquid retention. To reveal the water-induced changes of the polymer film, the polyimide surface was studied before and after the contact with a water droplet by VASE. Both the experimental ellipsometric spectrum for Delta and that for Psi as well as the corresponding simulations show characteristic shifts due to the contact with water. The so-called effective medium approximation was applied to recover information about the thickness and effective optical constants of the polymer layer from the ellipsometrically measured values of Delta and Psi. On the basis of these results, the swelling and retention behavior of the polyimide films in contact with water droplets were discussed.
Contact angle of unset elastomeric impression materials.
Menees, Timothy S; Radhakrishnan, Rashmi; Ramp, Lance C; Burgess, John O; Lawson, Nathaniel C
2015-10-01
Some elastomeric impression materials are hydrophobic, and it is often necessary to take definitive impressions of teeth coated with some saliva. New hydrophilic materials have been developed. The purpose of this in vitro study was to compare contact angles of water and saliva on 7 unset elastomeric impression materials at 5 time points from the start of mixing. Two traditional polyvinyl siloxane (PVS) (Aquasil, Take 1), 2 modified PVS (Imprint 4, Panasil), a polyether (Impregum), and 2 hybrid (Identium, EXA'lence) materials were compared. Each material was flattened to 2 mm and a 5 μL drop of distilled water or saliva was dropped on the surface at 25 seconds (t0) after the start of mix. Contact angle measurements were made with a digital microscope at initial contact (t0), t1=2 seconds, t2=5 seconds, t3=50% working time, and t4=95% working time. Data were analyzed with a generalized linear mixed model analysis, and individual 1-way ANOVA and Tukey HSD post hoc tests (α=.05). For water, materials grouped into 3 categories at all time-points: the modified PVS and one hybrid material (Identium) produced the lowest contact angles, the polyether material was intermediate, and the traditional PVS materials and the other hybrid (EXA'lence) produced the highest contact angles. For saliva, Identium, Impregum, and Imprint 4 were in the group with the lowest contact angle at most time points. Modified PVS materials and one of the hybrid materials are more hydrophilic than traditional PVS materials when measured with water. Saliva behaves differently than water in contact angle measurement on unset impression material and produces a lower contact angle on polyether based materials. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
Bioelectric impedance phase angle in breast carcinoma
Ruchi Tyagi
2014-01-01
Full Text Available Context: Worldwide breast cancer is the most frequently diagnosed life threatening cancer and the leading cause of death in women. Bioelectric impedance analysis (BIA affords an emerging opportunity to assess prognosis because of its ability to non invasively assess cell and plasma membrane structure and function by means of phase angle. Aims: To compare the phase angle between patients of breast cancer and their matched control with the help of BIA. Settings and Design: After taking clearance from ethical committee, a total of 34 female cases of histologically proven infiltrating ductal breast carcinoma were included from the surgery IPD, department of surgery. Equal numbers of the matched controls were recruited from the friends and relatives of cases. Materials and Methods: Bio Electrical Impedance Analyzer (BIA BODY STAT QUAD SCAN 4000 was used to measure resistance (R and reactance (Xc by recording a voltage drop in applied current. Phase angle is the ratio of reactance to resistance and is a measure of cell vitality. Statistical analysis used: Unpaired "t" test was applied. Results: In control group, the phase angle showed a mean of 5.479 whereas in test group, it showed a mean value of 4.726. The P value showed a significant difference (P < 0.0001. The smaller the phase angle values were higher was the tumor, nodes, metastases (TNM staging. The phase angles differed significantly from the healthy age matched control values. Conclusions: This study demonstrated that phase angle is a strong predictor of severity of breast cancer and differed significantly between the two groups.
LoCelso, F.; Triolo, F.; Triolo, A.; Lin, J.S.; Lucido, G.; Triolo, R.
1999-10-14
Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.
Lateral angle and cranial base sexual dimorphism
Duquesnel Mana, Mathilde; Adalian, Pascal; Lynnerup, Niels
2016-01-01
SUMMARY: Previous studies have yielded very different results in sex estimation based on measurements of the lateral angle (LA) of the temporal bone. The purpose of this study was to, first, investigate if the bad results obtained by the LA method could be due to the methodology and then, second......, to examine sexual dimorphism in the relationship between the lateral angle and cranial base shape. The lateral angle method was tested using a forensic sample of 102 CT scans of the head with known sex. We measured the angle using two methods: measurements directly on the CT slide, the method usually applied...... the direct measurements. The mean angle was greater in females (48.2° ± 7.2°) than in males (45.38° ±8.06°) but the difference was not significant (t-test, p = 0.063). A statistically significant difference in cranial base shape existed between the two sexes, but the results also demonstrated a major overlap...
PRIMARY OPEN ANGLE GLAUCOMA IN THYROID DISORDER
Pragati Garg
2016-07-01
Full Text Available PURPOSE To assess the association of thyroid profile with open angle glaucoma. DESIGN Cross-sectional observational study. MATERIAL AND METHOD 128 cases of diagnosed thyroid disorder were enrolled. 5 cases dropped out. Ocular examination included applanation tonometry, stereoscopic optic disc photography, and automated perimetry. Correlative association of thyroid disorder and open angle glaucoma was assessed. RESULTS Of 123 patients of thyroid disorder, 87.8% had hypothyroidism and remaining 12.2% had hyperthyroidism. 15.74% of hypothyroidism and 20% of hyperthyroidism patients had open angle glaucoma, which was statistically significant (Pearson chi-square: Value=6.548, df=2, p=0.040. On multivariate analysis with other risk factors like female sex, family history of glaucoma, myopia, hypertension, and diabetes; it was found that hypothyroidism is an independent risk factor for open angle glaucoma. CONCLUSION All patients having thyroid disorder should be investigated for early diagnosis of open angle glaucoma so that if need be antiglaucoma treatment is started at the earliest and the eye maybe saved from any further deterioration.
Three paths toward the quantum angle operator
Gazeau, Jean Pierre; Szafraniec, Franciszek Hugon
2016-12-01
We examine mathematical questions around angle (or phase) operator associated with a number operator through a short list of basic requirements. We implement three methods of construction of quantum angle. The first one is based on operator theory and parallels the definition of angle for the upper half-circle through its cosine and completed by a sign inversion. The two other methods are integral quantization generalizing in a certain sense the Berezin-Klauder approaches. One method pertains to Weyl-Heisenberg integral quantization of the plane viewed as the phase space of the motion on the line. It depends on a family of "weight" functions on the plane. The third method rests upon coherent state quantization of the cylinder viewed as the phase space of the motion on the circle. The construction of these coherent states depends on a family of probability distributions on the line.
Michelson interferometer for precision angle measurement.
Ikram, M; Hussain, G
1999-01-01
An angle-measuring technique based on an optical interferometer is reported. The technique exploits a Michelson interferometric configuration in which a right-angle prism and a glass strip are introduced into a probe beam. Simultaneous rotation of both components along an axis results in an optical path difference between the reference and the probe beams. In a second arrangement two right-angle prisms and glass strips are introduced into two beams of a Michelson interferometer. The prisms and the strips are rotated simultaneously to introduce an optical path difference between the two beams. In our arrangement, optimization of various parameters makes the net optical path difference between the two beams approximately linear for a rotation as great as +/-20 degrees . Results are simulated that show an improvement of 2-3 orders of magnitude in error and nonlinearity compared with a previously reported technique.
Tunable contact angle hysteresis on micropatterned surfaces
Debuisson, Damien; Arscott, Steve
2011-01-01
Micropatterned surfaces composed of concentric circular defects having a smooth trench-like profile are formed using a photoresist (SU-8). When an evaporating droplet encounters the micropatterned surface an evaporation phase is observed consisting of distinct discontinuities and steps in the droplet wetting contact angle and base radius respectively. The addition of gaps into the circular defects enables tuning of the contact angle hysteresis; the receding contact angle of fluorocarbon coated SU-8 can be tuned between 34.6{\\deg} and 89.1{\\deg} and that of SU-8 surfaces from 5.6{\\deg} to 43.3{\\deg} depending on the gap length. In addition, a model is developed which accurately predicts the observed behavior.
Magic-angle thermal desorption mass spectroscopy
Pauls, Steven W.; Campbell, Charles T.
1990-02-01
Accurate quantitative measurements of desorption rates or adsorbate coverages in thermal desorption mass spectroscopy (TDS) using line-of-sight mass spectrometers are hindered by the fact that the angular distributions of desorption flux can vary widely from desorbate to desorbate, ranging from cos 1ø to cos 9 ø for most species studied to date (ø = polar angle from surface normal). These differences can easily lead to errors exceeding 400% in measuring the relative desorption rates of different species. We show here that, by placing the mass spectrometer's ion source or entrance aperture at a "magic-angle" ø mthese errors can be reduced to less than 26% maximum deviation (or ± 7% standard deviation). Depending upon the sample-to-detector distance, ø m varies from ~ 42° to 34°. It is recommended that TDS experiments be performed at this "magic-angle" for improvement in the quantitative accuracy of coverage or rate measurements.
Notes on large angle crossing graphs
Dujmovic, Vida; Morin, Pat; Wolle, Thomas
2009-01-01
A graph G is an a-angle crossing (aAC) graph if every pair of crossing edges in G intersect at an angle of at least a. The concept of right angle crossing (RAC) graphs (a=Pi/2) was recently introduced by Didimo et. al. It was shown that any RAC graph with n vertices has at most 4n-10 edges and that there are infinitely many values of n for which there exists a RAC graph with n vertices and 4n-10 edges. In this paper, we give upper and lower bounds for the number of edges in aAC graphs for all 0 < a < Pi/2.
Weak lensing using only galaxy position angles
Whittaker, Lee; Battye, Richard
2013-01-01
We develop a method for performing a weak lensing analysis using only measurements of galaxy position angles. By analyzing the statistical properties of the galaxy orientations given a known intrinsic ellipticity distribution, we show that it is possible to obtain estimates of the shear by minimizing a $\\chi^2$ statistic. The method is demonstrated using simulations where the components of the intrinsic ellipticity are taken to be Gaussian distributed. Uncertainties on the position angle measurements introduce a bias into the shear estimates which can be reduced to negligible levels by introducing a correction term into the formalism. We generalize our approach by developing an algorithm to obtain direct shear estimators given any azimuthally symmetric intrinsic ellipticity distribution. We demonstrate this technique by applying it to simulations where the ellipticities are taken to follow a log-normal distribution. We compare the performance of the position angle only method with the standard method based on...
Precision measurements of the CKM angle gamma
CERN. Geneva
2016-01-01
The level of CP-violation permitted within the Standard Model cannot account for the matter dominated universe in which we live. Within the Standard Model the CKM matrix, which describes the quark couplings, is expected to be unitary. By making precise measurements of the CKM matrix parameters new physics models can be constrained, or with sufficient precision the effects of physics beyond the standard model might become apparent. The CKM angle gamma is the least well known angle of the unitarity triangle. It is the only angle easily accessible at tree-level, and furthermore has almost no theoretical uncertainties. Therefore it provides an invaluable Standard Model benchmark against which other new physics sensitive tests of the CP-violation can be made. I will discuss recent measurements of gamma using the the Run 1 LHCb dataset, which improve our knowledge of this key parameter.
Bicycle helmet ventilation and comfort angle dependence.
Brühwiler, Paul A; Ducas, Charline; Huber, Roman; Bishop, Phillip A
2004-09-01
Five modern bicycle helmets were studied to elucidate some of the variations in ventilation performance, using both a heated manikin headform and human subjects (n = 7). Wind speed and head angle were varied to test their influence on the measured steady-state heat exchange (cooling power) in the skull section of the headform. The cooling power transmitted by the helmets varied from about 60% to over 90% of that of the nude headform, illustrating the range of present manufacturer designs. Angling the head forward by 30 degrees was found to provide better cooling power to the skull (up to 25%) for three of the helmets and almost equal cooling power in the remaining two cases. Comparisons of skull ventilation at these angles with human subjects strongly supported the headform results.
Positron Emission Mammography with Multiple Angle Acquisition
Mark F. Smith; Stan Majewski; Raymond R. Raylman
2002-11-01
Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FbG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three-dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.
Positron Emission Mammography with Multiple Angle Acquisition
Mark F. Smith; Stan Majewski; Raymond R. Raylman
2002-11-01
Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FDG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three- dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.
Methodology for high accuracy contact angle measurement.
Kalantarian, A; David, R; Neumann, A W
2009-12-15
A new version of axisymmetric drop shape analysis (ADSA) called ADSA-NA (ADSA-no apex) was developed for measuring interfacial properties for drop configurations without an apex. ADSA-NA facilitates contact angle measurements on drops with a capillary protruding into the drop. Thus a much simpler experimental setup, not involving formation of a complete drop from below through a hole in the test surface, may be used. The contact angles of long-chained alkanes on a commercial fluoropolymer, Teflon AF 1600, were measured using the new method. A new numerical scheme was incorporated into the image processing to improve the location of the contact points of the liquid meniscus with the solid substrate to subpixel resolution. The images acquired in the experiments were also analyzed by a different drop shape technique called theoretical image fitting analysis-axisymmetric interfaces (TIFA-AI). The results were compared with literature values obtained by means of the standard ADSA for sessile drops with the apex. Comparison of the results from ADSA-NA with those from TIFA-AI and ADSA reveals that, with different numerical strategies and experimental setups, contact angles can be measured with an accuracy of less than 0.2 degrees. Contact angles and surface tensions measured from drops with no apex, i.e., by means of ADSA-NA and TIFA-AI, were considerably less scattered than those from complete drops with apex. ADSA-NA was also used to explore sources of improvement in contact angle resolution. It was found that using an accurate value of surface tension as an input enhances the accuracy of contact angle measurements.
Angle-Resolved Spectroscopy of Parametric Fluorescence
Hsu, Feng-kuo
2013-01-01
The parametric fluorescence from a nonlinear crystal forms a conical radiation pattern. We measure the angular and spectral distributions of parametric fluorescence in a beta-barium borate crystal pumped by a 405-nm diode laser employing angle-resolved imaging spectroscopy. The experimental angle-resolved spectra and the generation efficiency of parametric down conversion are compared with a plane-wave theoretical analysis. The parametric fluorescence is used as a broadband light source for the calibration of the instrument spectral response function in the wavelength range from 450 to 1000 nm.
Angles between Curves in Metric Measure Spaces
Han Bang-Xian
2017-08-01
Full Text Available The goal of the paper is to study the angle between two curves in the framework of metric (and metric measure spaces. More precisely, we give a new notion of angle between two curves in a metric space. Such a notion has a natural interplay with optimal transportation and is particularly well suited for metric measure spaces satisfying the curvature-dimension condition. Indeed one of the main results is the validity of the cosine formula on RCD*(K, N metric measure spaces. As a consequence, the new introduced notions are compatible with the corresponding classical ones for Riemannian manifolds, Ricci limit spaces and Alexandrov spaces.
Spherical Parameterization Balancing Angle and Area Distortions.
Nadeem, Saad; Su, Zhengyu; Zeng, Wei; Kaufman, Arie; Gu, Xianfeng
2017-06-01
This work presents a novel framework for spherical mesh parameterization. An efficient angle-preserving spherical parameterization algorithm is introduced, which is based on dynamic Yamabe flow and the conformal welding method with solid theoretic foundation. An area-preserving spherical parameterization is also discussed, which is based on discrete optimal mass transport theory. Furthermore, a spherical parameterization algorithm, which is based on the polar decomposition method, balancing angle distortion and area distortion is presented. The algorithms are tested on 3D geometric data and the experiments demonstrate the efficiency and efficacy of the proposed methods.
Crompton, Helen
2015-01-01
Mobile technologies are quickly becoming tools found in the educational environment. The researchers in this study use a form of mobile learning to support students in learning about angle concepts. Design-based research is used in this study to develop an empirically-substantiated local instruction theory about students' develop of angle and…
Using Digital Technology to See Angles from Different Angles. Part 2: Openings and Turns
Host, Erin; Baynham, Emily; McMaster, Heather
2015-01-01
Ever wondered how to use technology to teach angles? This article follows on from an earlier article published last year, providing a range of ideas for integrating technology and concrete materials with the teaching of angle concepts. The authors also provide a comprehensive list of free online games and learning objects that can be used to teach…
Crompton, Helen
2015-01-01
Mobile technologies are quickly becoming tools found in the educational environment. The researchers in this study use a form of mobile learning to support students in learning about angle concepts. Design-based research is used in this study to develop an empirically-substantiated local instruction theory about students' develop of angle and…
Angle at the Medial Border: The Spinovertebra Angle and Its Significance
G. S. Oladipo
2015-01-01
Full Text Available Background. The evolution from quadrupedalism to bipedalism has adjusted the balance of the upper limb to extensive movement at the shoulder. The scapular angles provide the point of attachment and control to various muscles and have been associated with the different movements of the shoulder girdle and joint. This has made the morphometric and anthropometric study of scapula a subject of extensive investigation. Aim. In the present study, the angle at the medial border was measured in the South-Southern Nigerian population and an anatomical name was ascribed to the angle. Method. The study was conducted on 173 scapulae (75 right and 98 left obtained from various Anatomy Department of South-Sothern Nigerian Universities. The angle at medial border was obtained by pinning the edge of the superior and inferior angles, the lined traced out, and the angle measured using a protractor. SPSS version 20 was used to analyse the data. t-test was used to determine mean angular difference in the sides. Result. The mean ± SD of the medial angle was observed to be 136.88 ± 7.70° (R = 138.13 ± 7.06° : L = 135.92 ± 8.05°. Statistical analysis using the Z-test for mean difference showed the medial angle was found to be higher in the right side of the scapula (mean difference of 2.214 ± 1.152°, but the observed difference was not statistically significant (P > 0.05. The above findings have adjusted the scapula from three to four angles (lateral, superior, inferior, and medial formed from four borders (lateral, superior, inferior, and superomedial and inferomedial. The medial angle because of its anatomical location was named “spinovertebral” angle, owing to its position at the scapulae spine, and located in medial proximity to the vertebra column. Conclusion. The medial angle (now referred to as the spinovertebral angle of the right side of the scapula is wider than the left. The representation of the spinovertebral angle is very important, as
A thin-film magnetoresistive angle detector
Eijkel, Kees J.M.; Wieberdink, Johan W.; Fluitman, Jan H.J; Popma, Theo J.A.; Groot, Peter; Leeuwis, Henk
1990-01-01
An overview is given of the results of our research on a contactless angle detector based on the anisotropic magnetoresistance effect (AMR effect) in a permalloy thin film. The results of high-temperature annealing treatment of the pemalloy film are discussed. Such a treatment suppresses the effects
Wind Turbine Blade with Angled Girders
2011-01-01
The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...
Incidence angle normalization of radar backscatter data
NASA’s Soil Moisture Passive Active (SMAP) satellite (~2014) will include a radar system that will provide L-band multi-polarization backscatter at a constant incidence angle of 40º. During the pre-launch phase of the project there is a need for observations that will support the radar-based soil mo...
[Cerebellopontine angle meningeal melanocytoma: a benign tumor?].
González-Tortosa, J; Ferri-Níguez, B; Ros de San Pedro, J
2009-08-01
We report a case of a rare meningeal melanocytoma in the cerebellopontine angle. One year after tumor gross total removal, the patient suffered a sudden and devastating meningeal melanomatosis. The relevant literature is reviewed looking for the keys to establish preoperative diagnosis and to obtain information about its treatment and postsurgical management.
Partitioning Pythagorean Triangles Using Pythagorean Angles
Swenson, Carl E.; Yandl, Andre L.
2012-01-01
Inside any Pythagorean right triangle, it is possible to find a point M so that drawing segments from M to each vertex of the triangle yields angles whose sines and cosines are all rational. This article describes an algorithm that generates an infinite number of such points.
Statistical analysis of Contact Angle Hysteresis
Janardan, Nachiketa; Panchagnula, Mahesh
2015-11-01
We present the results of a new statistical approach to determining Contact Angle Hysteresis (CAH) by studying the nature of the triple line. A statistical distribution of local contact angles on a random three-dimensional drop is used as the basis for this approach. Drops with randomly shaped triple lines but of fixed volumes were deposited on a substrate and their triple line shapes were extracted by imaging. Using a solution developed by Prabhala et al. (Langmuir, 2010), the complete three dimensional shape of the sessile drop was generated. A distribution of the local contact angles for several such drops but of the same liquid-substrate pairs is generated. This distribution is a result of several microscopic advancing and receding processes along the triple line. This distribution is used to yield an approximation of the CAH associated with the substrate. This is then compared with measurements of CAH by means of a liquid infusion-withdrawal experiment. Static measurements are shown to be sufficient to measure quasistatic contact angle hysteresis of a substrate. The approach also points towards the relationship between microscopic triple line contortions and CAH.
Measurement of the angle alpha at BABAR
Pérez, A
2009-01-01
We present recent measurements of the CKM angle alpha using data collected by the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider at the SLAC National Accelerator Laboratory, operating at the Upsilon(4S) resonance. We present constraints on alpha from B->pipi, B->rhorho and B->rhopi decays.
Molecular mechanisms underlying primary open angle glaucoma
Janssen, S.F.
2014-01-01
Primary open angle glaucoma (POAG) is a complex, multigenetic and heterogeneous optic neuropathy. It is an insidious disease that untreated leads to irreversible visual field loss and blindness. Worldwide, glaucoma causes around 12% of blindness. Although various risk factors have been established,
Constant Angle Surfaces in the Heisenberg Group
Johan FASTENAKELS; Marian Ioan MUNTEANU; Joeri VAN DER VEKEN
2011-01-01
In this article we extend the notion of constant angle surfaces in S2 × R and H2 × R to general Bianchi-Cartan-Vranceanu spaces. We show that these surfaces have constant Gaussian curvature and we give a complete local classification in the Heisenberg group.
Testing CMB polarization data using position angles
Preece, Michael
2014-01-01
We consider a novel null test for contamination which can be applied to CMB polarization data that involves analysis of the statistics of the polarization position angles. Specifically, we will concentrate on using histograms of the measured position angles to illustrate the idea. Such a test has been used to identify systematics in the NVSS point source catalogue with an amplitude well below the noise level. We explore the statistical properties of polarization angles in CMB maps. If the polarization angle is not correlated between pixels, then the errors follow a simple $\\sqrt{N_{pix}}$ law. However this is typically not the case for CMB maps since these have correlations which result in an increase in the variance since the effective number of independent pixels is reduced. Then we illustrate how certain classes of systematic errors can result in very obvious patterns in these histograms, and thus that these errors could possibly be identified using this method. We discuss how this idea might be applied in...
Measurement of the UT angle phi_2
Mohanty, Gagan B
2011-01-01
We give a status report on measurements of the angle phi_2 (alpha) of the CKM unitarity triangle (UT) and the so-called Kpi puzzle. Results presented are mostly from the two B-factory experiments, Belle and BaBar.
Contact Angle Effects in Boiling Heat Transfer
Urquiola, Erwin; Fujita, Yasunobu
2002-01-01
This paper reports boiling experiments with pure water and surfactant solutions of SDS on horizontal heating surface. The static contact angle, rather than the surface tension value, was found to be the leading factor for the results and probably its prev
Wind Turbine Blade with Angled Girders
2011-01-01
The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...
Camber Angle Inspection for Vehicle Wheel Alignments
Young, Jieh-Shian; Hsu, Hong-Yi; Chuang, Chih-Yuan
2017-01-01
This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU)-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ±0.015∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi. PMID:28165365
Camber Angle Inspection for Vehicle Wheel Alignments
Jieh-Shian Young
2017-02-01
Full Text Available This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ± 0.015 ∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi.
Marco Túlio Costa
2009-06-01
to severe hallux valgus with osteotomy of the first metatarsal base associated to distal release of soft parts and medial capsuloplasty. METHODS: 13 patients were assessed (15 feet submitted to surgical treatment of hallux valgus moderate to severe. The mean follow-up time was 102 months; there were 12 female and 1 male patients, with mean age at the time of surgery of 49 years. The patients enrolled were interviewed according to the questionnaire developed by our service, clinically examined according to the AOFAS scale and submitted to X-ray tests for comparing the results with baseline images. RESULTS: The mean score of the AOFAS scale obtained at the final assessment was 82 points. Nine of the 15 feet (60% showed some late complications, with four (27% varus deformities, three (20% recurrences; two patients (13% presenting with pain complaints with no associated deformity. In the hallux metatarsophalangeal joint, movement loss was 41º (57%; dorsiflexion movement was mostly affected, with a mean loss of 37º (60%. The range of motion on the contralateral intact side served as control group. Arthrosis progression was seen on the final X-ray evaluation. In all cases, shortening and lifting of the first metatarsal were noticed; however, we couldn't correlate the shortening and lifting with metatarsalgia, plant callosity or lower scoring on the AOFAS scale at the final evaluation. CONCLUSIONS: The osteotomy technique by the basis and with distal realignment of soft parts employed in the treatment of moderate to severe hallux valgus showed a high rate of late complications. Due to the high number of complications, we believe that adopting this technique for correcting hallux valgus deformities should be carefully considered.
Resultados y prospectiva de la investigación podológica en el baile flamenco.
José Manuel Castillo-López
2016-11-01
Full Text Available La expansión mundial y el grado de profesionalización del baile flamenco han equiparado las demandas físicas de esta forma dancística a la de cualquier disciplina deportiva de alto rendimiento. El propio gesto técnico del flamenco, especialmente el zapateado y el impacto que éste genera, es el principal factor predisponentes de lesiones en los pies y miembros inferiores. De estas lesiones, destacan por su alta incidencia el hallux abductus valgus, dedos en garra, juanetes de sastre y onicodistrofias, además de problemas de sobrecarga y dolor metatarsal, que afecta a más del 80% de la muestra analizada, 44 bailaoras profesionales de flamenco con más de 20h de práctica semanal de baile. Desde el campo de la podología, han sido registradas dos patentes dirigidas a prevenir y/o paliar la sintomatología asociada a estas patologías y alteraciones podológicas: soportes plantares y calzado fisiológico para baile flamenco. The global expansion and the degree of flamenco dancing professionalization have matched the physical demands of this dance to any high-performance sport. The technical gesture, typical of flamenco, especially the footwork and its generated impacts, is the main predisposing factor of injury in feet and lower limbs. Forty four professional flamenco dancers, with more than 20 hours of weekly dance practice, have been studied. The following injuries are noted for their high incidence: hallux abductus valgus, hammertoes, bunions tailor, onychodystrophy, overload problems and metatarsal pain, which affect more than 80% of the sample. From the field of podiatry, two patents have been registered to prevent and/or alleviate the symptoms associated with these diseases and podiatry disorders: orthotic devices and physiological footwear for flamenco dancing.
Experimental Validation of the Invariance of Electrowetting Contact Angle Saturation
Chevalliot, S.; Dhindsa, M.; Kuiper, S.; Heikenfeld, J.
2011-01-01
Basic electrowetting theory predicts that a continued increase in applied voltage will allow contact angle modulation to zero degrees. In practice, the effect of contact angle saturation has always been observed to limit the contact angle modulation, often only down to a contact angle of 60 to 70°.
On some relations between advancing, receding and Young's contact angles.
Chibowski, Emil
2007-05-31
Problems of experimental determination and theoretical verification of equilibrium contact angles are discussed basing on the literature data. A relationship between the advancing and receding contact angles versus the equilibrium contact angle is described and then verified using the literature contact angles determined on paraffin wax and polypropylene. Using the proposed relationship and experimentally determined equilibrium contact angles, obtained by plotting the advancing and receding contact angles versus the contact angle hysteresis or by applying vibration of the system liquid drop/solid surface, it is found that the same value of the surface free energy for paraffin wax is calculated from the contact angles of water and ethylene glycol. However, in the case of polypropylene some inconsistency appears between the equilibrium contact angles of the probe liquid used and the calculated surface free energy. More experimental data of the equilibrium contact angle are needed to verify further the relationship.
Contact angle and contact angle hysteresis measurements using the capillary bridge technique.
Restagno, Frédéric; Poulard, Christophe; Cohen, Céline; Vagharchakian, Laurianne; Léger, Liliane
2009-09-15
A new experimental technique is proposed to easily measure both advancing and receding contact angles of a liquid on a solid surface, with unprecedented accuracy. The technique is based on the analysis of the evolution of a capillary bridge formed between a liquid bath and a solid surface (which needs to be spherical) when the distance between the surface and the liquid bath is slowly varied. The feasibility of the technique is demonstrated using a low-energy perfluorinated surface with two different test liquids (water and hexadecane). A detailed description of both experimental procedures and computational modeling are given, allowing one to determine contact angle values. It is shown that the origin of the high accuracy of this technique relies on the fact that the contact angles are automatically averaged over the whole periphery of the contact. This method appears to be particularly adapted to the characterization of surfaces with very low contact angle hysteresis.
The Contact Angle in Inviscid Fluid Mechanics
P N Shankar; R Kidambi
2005-05-01
We show that in general, the specification of a contact angle condition at the contact line in inviscid fluid motions is incompatible with the classical field equations and boundary conditions generally applicable to them. The limited conditions under which such a specification is permissible are derived;however, these include cases where the static meniscus is not flat. In view of this situation, the status of the many `solutions’ in the literature which prescribe a contact angle in potential flows comes into question. We suggest that these solutions which attempt to incorporate a phenomenological, but incompatible, condition are in some, imprecise sense `weak-type solutions’;they satisfy or are likely to satisfy, at least in the limit, the governing equations and boundary conditions everywhere except in the neighbourhood of the contact line. We discuss the implications of the result for the analysis of inviscid flows with free surfaces.
Picoliter water contact angle measurement on polymers.
Taylor, Michael; Urquhart, Andrew J; Zelzer, Mischa; Davies, Martyn C; Alexander, Morgan R
2007-06-19
Water contact angle measurement is the most common method for determining a material's wettability, and the sessile drop approach is the most frequently used. However, the method is generally limited to macroscopic measurements because the base diameter of the droplet is usually greater than 1 mm. Here we report for the first time on a dosing system to dispense smaller individual droplets with control of the position and investigate whether water contact angles determined from picoliter volume water droplets are comparable with those obtained from the conventional microliter volume water droplets. This investigation was conducted on a group of commonly used polymers. To demonstrate the higher spatial resolution of wettability that can be achieved using picoliter volume water droplets, the wettability of a radial plasma polymer gradient was mapped using a 250 microm interval grid.
Sparse regularization in limited angle tomography
Frikel, Jürgen
2011-01-01
We investigate the reconstruction problem of limited angle tomography. Such problems arise naturally in applications like digital breast tomosynthesis, dental tomography, electron microscopy etc. Since the acquired tomographic data is highly incomplete, the reconstruction problem is severely ill-posed and the traditional reconstruction methods, such as filtered backprojection (FBP), do not perform well in such situations. To stabilize the reconstruction procedure additional prior knowledge about the unknown object has to be integrated into the reconstruction process. In this work, we propose the use of the sparse regularization technique in combination with curvelets. We argue that this technique gives rise to an edge-preserving reconstruction. Moreover, we show that the dimension of the problem can be significantly reduced in the curvelet domain. To this end, we give a characterization of the kernel of limited angle Radon transform in terms of curvelets and derive a characterization of solutions obtained thr...
The small angle diffractometer SANS at PSI
Wagner, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1996-11-01
With the start-up of SINQ an instrument for small angle neutron scattering will be operational which compares well with the world`s largest and most powerful facilities of this kind. Following the classical principle of the D11-instrument of ILL, it is equipped with state-of-the-art components as are nowadays available, including options for further upgrading. Great emphasis was laid upon providing a flexible, universal multi-user facility which guarantees a comfortable and reliable operation. In the present paper, the principle layout of the instrument is presented, and the individual components are described in detail. The paper concludes with model application of small angle scattering to a system of dilute CuCo alloys which undergo a phase separation under thermal treatment, forming spherical Co-precipitates dispersed in a Cu-rich matrix. (author) 3 figs., 1 tab., 14 refs.
Gaia: focus, straylight and basic angle
Mora, A; Bombrun, A; Boyadian, J; Chassat, F; Corberand, P; Davidson, M; Doyle, D; Escolar, D; Gielesen, W L M; Guilpain, T; Hernandez, J; Kirschner, V; Klioner, S A; Koeck, C; Laine, B; Lindegren, L; Serpell, E; Tatry, P; Thoral, P
2016-01-01
The Gaia all-sky astrometric survey is challenged by several issues affecting the spacecraft stability. Amongst them, we find the focus evolution, straylight and basic angle variations Contrary to pre-launch expectations, the image quality is continuously evolving, during commissioning and the nominal mission. Payload decontaminations and wavefront sensor assisted refocuses have been carried out to recover optimum performance. An ESA-Airbus DS working group analysed the straylight and basic angle issues and worked on a detailed root cause analysis. In parallel, the Gaia scientists have also analysed the data, most notably comparing the BAM signal to global astrometric solutions, with remarkable agreement. In this contribution, a status review of these issues will be provided, with emphasis on the mitigation schemes and the lessons learned for future space missions where extreme stability is a key requirement.
Gaia: focus, straylight and basic angle
Mora, A.; Biermann, M.; Bombrun, A.; Boyadjian, J.; Chassat, F.; Corberand, P.; Davidson, M.; Doyle, D.; Escolar, D.; Gielesen, W. L. M.; Guilpain, T.; Hernandez, J.; Kirschner, V.; Klioner, S. A.; Koeck, C.; Laine, B.; Lindegren, L.; Serpell, E.; Tatry, P.; Thoral, P.
2016-07-01
The Gaia all-sky astrometric survey is challenged by several issues affecting the spacecraft stability. Amongst them, we find the focus evolution, straylight and basic angle variations Contrary to pre-launch expectations, the image quality is continuously evolving, during commissioning and the nominal mission. Payload decontaminations and wavefront sensor assisted refocuses have been carried out to recover optimum performance. An ESA-Airbus DS working group analysed the straylight and basic angle issues and worked on a detailed root cause analysis. In parallel, the Gaia scientists have also analysed the data, most notably comparing the BAM signal to global astrometric solutions, with remarkable agreement. In this contribution, a status review of these issues will be provided, with emphasis on the mitigation schemes and the lessons learned for future space missions where extreme stability is a key requirement.
Absorbing angles, Steiner minimal trees, and antipodality
Martini, Horst; de Wet, P Oloff; 10.1007/s10957-009-9552-1
2011-01-01
We give a new proof that a star $\\{op_i:i=1,...,k\\}$ in a normed plane is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles formed by the edges at o are absorbing [Swanepoel, Networks \\textbf{36} (2000), 104--113]. The proof is more conceptual and simpler than the original one. We also find a new sufficient condition for higher-dimensional normed spaces to share this characterization. In particular, a star $\\{op_i: i=1,...,k\\}$ in any CL-space is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles are absorbing, which in turn holds if and only if all distances between the normalizations $\\frac{1}{\\|p_i\\|}p_i$ equal 2. CL-spaces include the mixed $\\ell_1$ and $\\ell_\\infty$ sum of finitely many copies of $R^1$.
Magic-angle turning with double acquisition.
Matsunaga, Tatsuya; Takegoshi, K
2017-01-01
The double-acquisition scheme for efficient data collection of hypercomplex data (the States method) of a two-dimensional experiment is adopted to magic-angle hopping (MAH) and magic-angle turning (MAT) experiments, which are powerful methods to measure the principal values of the chemical shift anisotropy (CSA) in a powder sample. It is shown that the double acquisition MAT (DAMAT) sequence realizes the S/N ratio comparable to or better than those of other variants of the MAH/MAT sequences. In addition, we show that DAMAT has preferable features that there are no spinning sidebands in the indirect dimension, and no spectral shearing is necessary. Copyright © 2016 Elsevier Inc. All rights reserved.
Reactor mixing angle from hybrid neutrino masses
Sierra, D Aristizabal
2014-01-01
In terms of its eigenvector decomposition, the neutrino mass matrix (in the basis where the charged lepton mass matrix is diagonal) can be understood as originating from a tribimaximal dominant structure with small deviations, as demanded by data. If neutrino masses originate from at least two different mechanisms, referred to as "hybrid neutrino masses", the experimentally observed structure naturally emerges provided one mechanism accounts for the dominant tribimaximal structure while the other is responsible for the deviations. We demonstrate the feasibility of this picture in a fairly model-independent way by using lepton-number-violating effective operators, whose structure we assume becomes dictated by an underlying $A_4$ flavor symmetry. We show that if a second mechanism is at work, the requirement of generating a reactor angle within its experimental range always fixes the solar and atmospheric angles in agreement with data, in contrast to the case where the deviations are induced by next-to-leading ...
Dancing droplets: Contact angle, drag, and confinement
Benusiglio, Adrien; Cira, Nate; Prakash, Manu
2015-11-01
When deposited on a clean glass slide, a mixture of water and propylene glycol forms a droplet of given contact angle, when both pure liquids spread. (Cira, Benusiglio, Prakash: Nature, 2015). The droplet is stabilized by a gradient of surface tension due to evaporation that induces a Marangoni flow from the border to the apex of the droplets. The apparent contact angle of the droplets depends on both their composition and the external humidity as captured by simple models. These droplets present remarkable properties such as lack of a large pinning force. We discuss the drag on these droplets as a function of various parameters. We show theoretical and experimental results of how various confinement geometries change the vapor gradient and the dynamics of droplet attraction.
AGN jet physics and apparent opening angles
Clausen-Brown, Eric; Pushkarev, Alexander B; Kovalev, Yuri Y; Lister, Matthew L
2013-01-01
We present a new method to measure Gamma*theta_j in flux-limited samples of active galactic nuclei (AGN) jets, where Gamma is the bulk Lorentz factor and theta_j is the jet's half-opening angle. The Gamma*theta_j parameter is physically important for models of jet launching, and also determines the effectiveness of jet instabilities and magnetic reconnection. We measure Gamma*theta_j by analyzing the observed distribution of apparent opening angles in very long baseline interferometry (VLBI) flux-limited samples of jets, given some prior knowledge of the active galactic nuclei (AGN) radio luminosity function. We then apply this method to the MOJAVE flux-limited sample of radio loud objects and find Gamma*theta_j = 0.1 +- 0.03, which implies that AGN jets are subject to a variety of physical processes that require causal connection.
Measurement of the angle alpha at BABAR
Perez, A.; /Orsay, LAL
2009-06-25
The authors present recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory, operating at the {Upsilon}(4S) resonance. They present constraints on {alpha} from B {yields} {pi}{pi}, B {yields} {rho}{rho} and B {yields} {rho}{pi} decays.
Contact angle hysteresis at the nanometer scale.
Delmas, Mathieu; Monthioux, Marc; Ondarçuhu, Thierry
2011-04-01
Using atomic force microscopy with nonconventional carbon tips, the pinning of a liquid contact line on individual nanometric defects was studied. This mechanism is responsible for the occurrence of the contact angle hysteresis. The presence of weak defects which do not contribute to the hysteresis is evidenced for the first time. The dissipated energy associated with strong defects is also measured down to values in the range of kT, which correspond to defect sizes in the order of 1 nm.
On accurate determination of contact angle
Concus, P.; Finn, R.
1992-01-01
Methods are proposed that exploit a microgravity environment to obtain highly accurate measurement of contact angle. These methods, which are based on our earlier mathematical results, do not require detailed measurement of a liquid free-surface, as they incorporate discontinuous or nearly-discontinuous behavior of the liquid bulk in certain container geometries. Physical testing is planned in the forthcoming IML-2 space flight and in related preparatory ground-based experiments.
Primary open-angle glaucoma genes
Fingert, J.H.
2011-01-01
A substantial fraction of glaucoma has a genetic basis. About 5% of primary open angle glaucoma (POAG) is currently attributed to single-gene or Mendelian forms of glaucoma (ie glaucoma caused by mutations in myocilinor optineurin). Mutations in these genes have a high likelihood of leading to glaucoma and are rarely seen in normal subjects. Other cases of POAG have a more complex genetic basis and are caused by the combined effects of many genetic and environmental risk factors, each of whic...
Constraining the CKM angle $\\gamma$ at LHCb
Vallier, Alexis
2015-01-01
A selection of latest LHCb measurements related to the determination of the CKM angle $\\gamma$ is presented. Included are: the current combination of direct $\\gamma$ measurements, the first observation of the $B^0_s \\to D^{*±} K^±$ decay, the first observation and amplitude analysis of the $B^- \\to D^+ K^- \\pi^-$ decay and the constraint on $\\gamma$ from charmless B decays
Black hole microstates from branes at angle
Pieri, Lorenzo
2016-01-01
We derive the leading g_s perturbation of the SUGRA fields generated by a supersymmetric configuration of respectively 1, 2 or 4 D3-branes intersecting at an arbitrary angle via the computation of the string theory disk scattering amplitude of one massless NSNS field interacting with open strings stretched between the branes. The configuration with four branes is expected to be relevant for black hole microstate counting in four dimensions.
Target Localization Based on Angle of Arrivals
Yi-Chao Cao
2007-01-01
Mobile location using angle of arrival (AOA) measurements has received considerable attention. This paper presents an approximation of maximum likelihood estimator (MLE) for localizing a source based on AOA measurements. By introducing an intermediate variable, the nonlinear equations relating AOA estimates can be transformed into a set of equations which are linear in the unknown parameters. It is an approximate realization of the MLE. Simulations show that the proposed algorithm outperforms the previous contribution.
Wireless Orbiter Hang-Angle Inclinometer System
Lucena, Angel; Perotti, Jose; Green, Eric; Byon, Jonathan; Burns, Bradley; Mata, Carlos; Randazzo, John; Blalock, Norman
2011-01-01
A document describes a system to reliably gather the hang-angle inclination of the orbiter. The system comprises a wireless handheld master station (which contains the main station software) and a wireless remote station (which contains the inclinometer sensors, the RF transceivers, and the remote station software). The remote station is designed to provide redundancy to the system. It includes two RF transceivers, two power-management boards, and four inclinometer sensors.
Angles-Let's treat them squarely
Brownstein, K. R.
1997-07-01
We suggest a self-consistent treatment of the dimensions and units of the geometric quantity "angle." The method regards "angle" as a fundamental dimensional physical quantity, on a par with length, mass, time, etc. All units (whether angular or otherwise) are treated on an equal footing and balance out correctly; in particular, "radian" units need never be spuriously inserted or deleted. The method could find application in algebraic and calculus symbolic manipulation computer programs to correctly process units of physical quantities. The technique necessitates a minor modification of the relation "s=Rθ" and its consequences, rather than any modification of the units of other physical quantities (such as moment arms) as previously suggested by others. We make several important clarifying distinctions: (a) ω [SI: radṡs-1] for rotational motion (as in θ=ωt) versus Ω [SI: s-1] for simple harmonic motion [as in x=xm cos(Ωt)], (b) geometric trigonometric functions whose arguments are angles [SI: rad] versus mathematical trigonometric functions whose arguments are pure numbers, (c) simple harmonic motion versus uniform circular motion in the reference circle analogy.
Multi-Angle Snowflake Camera Instrument Handbook
Stuefer, Martin [University of Alaska--Fairbanks; Bailey, J [University of Alaska--Fairbanks
2016-07-01
The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASC cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.
Angle-resolved optical coherence tomography
Desjardins, Adrien Emmanuel
Optical coherence tomography (OCT) has emerged as a powerful tool for probing the microstructure of biological tissue non-invasively at high-speed. OCT measures depth-resolved reflectance of infrared light, generating cross-sectional images non-invasively with micron-scale resolution. As with other imaging modalities that employ coherent detection, OCT images are confounded by speckle noise. Speckle imposes a grainy texture on images that reduces the signal-to-noise ratio to near unity values. As a result, it conceals subtle differences in scattering properties known to be crucial for differentiating normal from diseased tissue states. In this thesis, we developed a novel OCT modality called "Angle-Resolved OCT" in which depth scans (A-lines) are obtained simultaneously from a broad range of backscattering angles. We demonstrated that high levels of speckle reduction can be achieved by averaging the magnitudes of A-lines corresponding to the same transverse locations. With both experimental and analytic approaches, we demonstrated that this averaging method does not lead to a substantial loss in spatial resolution. We developed two different imaging systems for performing Angle-Resolved OCT. With the first system, angular data was acquired simultaneously; with the second, it was acquired sequentially. The first system had superior speckle-reduction capabilities but image quality degraded significantly with small sample movements. The second system allowed for in vivo imaging, as demonstrated with Resolved OCT systems, the speckle-reduced images showed hitherto unprecedented delineation of tissue microstructure.
Constitutive modeling of contact angle hysteresis.
Vedantam, Srikanth; Panchagnula, Mahesh V
2008-05-15
We introduce a phase field model of wetting of surfaces by sessile drops. The theory uses a two-dimensional non-conserved phase field variable to parametrize the Gibbs free energy of the three-dimensional system. Contact line tension and contact angle hysteresis arise from the gradient term in the free energy and the kinetic coefficient respectively. A significant advantage of this approach is in the constitutive specification of hysteresis. The advancing and receding angles of a surface, the liquid-vapor interfacial energy and three-phase line tension are the only required constitutive inputs to the model. We first simulate hysteresis on a smooth chemically homogeneous surface using this theory. Next we show that it is possible to study heterogeneous surfaces whose component surfaces are themselves hysteretic. We use this theory to examine the wetting of a surface containing a circular heterogeneous island. The contact angle for this case is found to be determined solely by the material properties at the contact line in accord with recent experimental data.
Dynamic contact angle cycling homogenizes heterogeneous surfaces.
Belibel, R; Barbaud, C; Mora, L
2016-12-01
In order to reduce restenosis, the necessity to develop the appropriate coating material of metallic stent is a challenge for biomedicine and scientific research over the past decade. Therefore, biodegradable copolymers of poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) were prepared in order to develop a new coating exhibiting different custom groups in its side chain and being able to carry a drug. This material will be in direct contact with cells and blood. It consists of carboxylic acid and hexylic groups used for hydrophilic and hydrophobic character, respectively. The study of this material wettability and dynamic surface properties is of importance due to the influence of the chemistry and the potential motility of these chemical groups on cell adhesion and polymer kinetic hydrolysis. Cassie theory was used for the theoretical correction of contact angles of these chemical heterogeneous surfaces coatings. Dynamic Surface Analysis was used as practical homogenizer of chemical heterogeneous surfaces by cycling during many cycles in water. In this work, we confirmed that, unlike receding contact angle, advancing contact angle is influenced by the difference of only 10% of acidic groups (%A) in side-chain of polymers. It linearly decreases with increasing acidity percentage. Hysteresis (H) is also a sensitive parameter which is discussed in this paper. Finally, we conclude that cycling provides real information, thus avoiding theoretical Cassie correction. H(10)is the most sensible parameter to %A.
Off-Angle Iris Correction Methods
Santos-Villalobos, Hector J [ORNL; Thompson, Joseph T [ORNL; Karakaya, Mahmut [ORNL; Boehnen, Chris Bensing [ORNL
2016-01-01
In many real world iris recognition systems obtaining consistent frontal images is problematic do to inexperienced or uncooperative users, untrained operators, or distracting environments. As a result many collected images are unusable by modern iris matchers. In this chapter we present four methods for correcting off-angle iris images to appear frontal which makes them compatible with existing iris matchers. The methods include an affine correction, a retraced model of the human eye, measured displacements, and a genetic algorithm optimized correction. The affine correction represents a simple way to create an iris image that appears frontal but it does not account for refractive distortions of the cornea. The other method account for refraction. The retraced model simulates the optical properties of the cornea. The other two methods are data driven. The first uses optical flow to measure the displacements of the iris texture when compared to frontal images of the same subject. The second uses a genetic algorithm to learn a mapping that optimizes the Hamming Distance scores between off-angle and frontal images. In this paper we hypothesize that the biological model presented in our earlier work does not adequately account for all variations in eye anatomy and therefore the two data-driven approaches should yield better performance. Results are presented using the commercial VeriEye matcher that show that the genetic algorithm method clearly improves over prior work and makes iris recognition possible up to 50 degrees off-angle.
Wide Angle Effects in Galaxy Surveys
Yoo, Jaiyul
2013-01-01
Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...
Head flexion angle while using a smartphone.
Lee, Sojeong; Kang, Hwayeong; Shin, Gwanseob
2015-01-01
Repetitive or prolonged head flexion posture while using a smartphone is known as one of risk factors for pain symptoms in the neck. To quantitatively assess the amount and range of head flexion of smartphone users, head forward flexion angle was measured from 18 participants when they were conducing three common smartphone tasks (text messaging, web browsing, video watching) while sitting and standing in a laboratory setting. It was found that participants maintained head flexion of 33-45° (50th percentile angle) from vertical when using the smartphone. The head flexion angle was significantly larger (p smartphone, could be a main contributing factor to the occurrence of neck pain of heavy smartphone users. Practitioner Summary: In this laboratory study, the severity of head flexion of smartphone users was quantitatively evaluated when conducting text messaging, web browsing and video watching while sitting and standing. Study results indicate that text messaging while sitting caused the largest head flexion than that of other task conditions.
Protein Amyloidogenesis Investigated by Small Angle Scattering.
Ricci, Caterina; Spinozzi, Francesco; Mariani, Paolo; Ortore, Maria Grazia
2016-01-01
In the last decades, the study of the mechanisms inducing amyloid fibril formation has involved several experimental and theoretical biophysical approaches. Many efforts have been made by scientist at the borderline between biology, chemistry, biochemistry and physics in order to understand why and in which way a protein starts its amyloidogenic pattern. This fundamental research issue is evolving in parallel to the development of drugs and inhibitors able to modify protein self assembly towards amyloid fibrils. Small angle xray and neutron scattering experiments represent suitable methods to investigate protein amyloidogenesis and the possible effects of inhibitors: they are in-solution techniques, require low amount of sample and their time-resolution makes it possible to follow aggregation pattern. In this paper we review small angle x-ray and neutron scattering studies dedicated to investigate amyloid β peptide and α-synuclein, related to Alzheimer`s and Parkinson`s diseases, respectively, together with some other studies that introduced innovative models to describe with small angle scattering techniques amyloid fibrillation processes.
The Brewster angle effect in SAR polarimetry
Chapman, B.
1993-01-01
For the double bounce case, where the radar signal is reflected twice before returning to the radar antenna, some polarization effects may be observed related to the dielectric constant of the two surfaces causing the reflections. The most noticeable effect would be that the returned signal would be preferentially H polarized. In fact, it may be possible to discern the Brewster angle for both surfaces. The locations of the Brewster angle will depend on the dielectric constant and permittivity of each surface. If it is assumed that both reflections are in the same plane of incidence, and that both surfaces are smooth and flat, there is a straightforward relationship between the degree of linear polarization m and both the dielectric constants of the two reflecting surfaces and the angle of incidence of the illuminating wave: m carat = cos 2(arccot (square root of (R(sub v) / R(sub h)))) where R(sub v,h) are the V and H polarized Fresnel reflection coefficients for two surfaces perpendicular to each other. The degree of linear polarization may be calculated from AIRSAR compressed Stokes data and compared with the given equation. The degree of linear polarization may also be calculated using tree models and compared with AIRSAR data. With further work, it may be possible to use the degree of linear polarization to determine surface parameters of certain imaged areas.
Visual estimation of pro-supination angle is superior to wrist or elbow angles.
Luria, Shai; Apt, Elad; Kandel, Leonid; Bdolah-Abram, Tali; Zinger, Gershon
2015-05-01
To examine our hypothesis that the accuracy of visual estimation, while measuring the angles of forearm, wrist and elbow, may vary between the different angles, and that this may depend on the experience of the observer. A slide show comprising of clinical photos and radiographs of different elbow, forearm and wrist angles was presented to 164 attending orthopedic surgeons, orthopedic residents and medical students who made a visual estimation of the different joints' angles. Forearm pronation was found to be estimated most accurately (mean 6.1°) while radiographs of wrist flexion (mean 12°) and photos of wrist extension (mean 16°) were estimated the least accurately. Specialists estimated angles more accurately than residents and both were more accurate than students, regardless of the estimated joint. The accuracy of visual estimation of a joint's angle depends on the specific joint viewed. Experience in the practice of orthopedic surgery (and not only upper extremity surgery) will improve the accuracy of estimation in general. Regarding the elbow, forearm and wrist, the results of our study suggest that a goniometer should be used whenever an accuracy of up to 10° is important, and for measuring wrist flexion and extension.
Pair Creation at Large Inherent Angles
Chen, P.; Tauchi, T.; Schroeder, D.V.; /SLAC
2007-04-25
In the next-generation linear colliders, the low-energy e{sup +}e{sup -} pairs created during the collision of high-energy e{sup +}e{sup -} beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al[1]. At energies where the beamstrahlung parameter {Upsilon} lies approximately in the range 0.6 {approx}< {Upsilon} {approx}< 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen[2]. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. One source of transverse momentum is from the kick by the field of the oncoming beam which results in an outcoming angle {theta} {proportional_to} 1/{radical}x, where x is the fractional energy of the particle relative to the initial beam particle energy[2,3]. As was shown in Ref. 131, there in fact exists an energy threshold for the coherent pairs, where x{sub th} {approx}> 1/2{Upsilon}. Thus within a tolerable exiting angle, there exists an upper limit for {Upsilon} where all coherent pairs would leave the detector through the exhaust port[4]. A somewhat different analysis has been done by Schroeder[5]. In the next generation of linear colliders, as it occurs, the coherent pairs can be exponentially suppressed[2] by properly choosing the {Upsilon}({approx}< 0.6). When this is achieved, the incoherent pairs becomes dominant. Since the central issue is the transverse momentum for particles with large angles, we notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. This issue was
Research on recognition of ramp angle based on transducer
Wenhao GU
2015-12-01
Full Text Available Focusing on the recognition of ramp angle, the relationship between the signal of vehicle transducer and real ramp angle is studied. The force change of vehicle on the ramp, and the relationship between the body tilt angle and front and rear suspension scale is discussed. According to the suspension and tire deformation, error angle of the ramp angle is deduced. A mathematical model is established with Matlab/Simulink and used for simulation to generate error curve of ramp angle. The results show that the error angle increases with the increasing of the ramp angle, and the limit value can reach 6.5%, while the identification method can effectively eliminate this error, and enhance the accuracy of ramp angle recognition.
邓婷; 贾建平; 吴格日勒
2007-01-01
目的 讨论巴宾斯基征拇趾背屈角度、持续时间和肢体肌力变化关系及引出巴宾斯基征敏感轨迹点的变化规律.方法 对锥体束首次损害的106例患者从急性期到恢复期的整个病程中每天查体1次,记录巴宾斯基征检查中手划时间、拇趾背屈时间、拇趾背屈角度、趾手始动时间差和瘫痪肢体肌力,并进行统计学分析.结果 和结论肌力越弱,拇趾背屈角度越大,拇趾背屈持续时间越长,引出巴宾斯基征敏感轨迹点越接近足跟部;病情减轻,拇趾背屈时间变短,敏感点越接近趾跖部.
Determining surface wave arrival angle anomalies
Larson, Erik W. F.; Ekström, Göran
2002-06-01
A new method for measuring arrival angles of teleseismic Love and Rayleigh waves is developed. The new method utilizes estimates of surface wave dispersion to create a phase-matched filter to isolate the Love or Rayleigh wave in three-component recordings. The polarization of the filtered wave group is determined in the time domain by application of a variation of the complex polarization method of Vidale [1986]. Orientation, linearity, and ellipticity of particle motion are estimated in several frequency bands to determine the frequency-dependent polarization. The method employs an iterative scheme, by which a predicted Love wave, based on the estimated dispersion and polarization, is subtracted from the three-component data prior to the estimation of Rayleigh wave polarization, and vice versa. The method is applied to an extensive set of Global Seismographic Network data covering the years 1989-1998. Between 4244 and 15,075 measurements are collected for fundamental mode Love and Rayleigh waves at nine different periods (37 to 150 s). Measurement uncertainties are estimated using the statistics of observations for pairwise similar paths and are generally of the order of 15-50% of the total signal, depending on the period and the wave type. Large and azimuthally invariant angle anomalies are documented for several stations and are consistent with misorientation of the horizontal seismometers. Two schemes are employed to determine the misorientations: (1) an azimuthally weighted average at each station, and (2) a joint inversion for seismometer misorientation and globally heterogeneous phase velocities. The determined corrections are robust and correlate well with those reported in earlier studies. Azimuthally varying arrival angle anomalies are shown to agree qualitatively with predictions of wave refraction calculated for recent phase velocity maps, which explain up to 30% of the variance in the new measurements.
Wren, Tishya A L; Mitiguy, Paul C
2007-08-01
Clinical gait analysis usually describes joint kinematics using Euler angles, which depend on the sequence of rotation. Studies have shown that pelvic obliquity angles from the traditional tilt-obliquity-rotation (TOR) Euler angle sequence can deviate considerably from clinical expectations and have suggested that a rotation-obliquity-tilt (ROT) Euler angle sequence be used instead. We propose a simple alternate approach in which clinical joint angles are defined and exactly calculated in terms of Euler angles from any rotation sequence. Equations were derived to calculate clinical pelvic elevation, progression, and lean angles from TOR and ROT Euler angles. For the ROT Euler angles, obliquity was exactly the same as the clinical elevation angle, rotation was similar to the clinical progression angle, and tilt was similar to the clinical lean angle. Greater differences were observed for TOR. These results support previous findings that ROT is preferable to TOR for calculating pelvic Euler angles for clinical interpretation. However, we suggest that exact clinical angles can and should be obtained through a few extra calculations as demonstrated in this technical note.
Optimum Staging with Varying Thrust Attitude Angle
T. N. Srivastava
1966-07-01
Full Text Available Optimum staging programme for step rockets of arbitrary number of stages having different specific impulses and mass fractions with stages is derived, the optimization criterion being minimum take-off weight for a desired burntout velocity at an assigned altitude. Variation of thrust attitude angle from stage to stage and effects of gravity factor are taken into account. Analysis is performed for a degenerate problem obtained by relaxing the altitude constraint and it has been shown that problems of Weisbord, Subotowicz, Hall & Zambelli and Malina & Summerfield are the particular cases of the degenerate problem.
Rapidly-Indexing Incremental-Angle Encoder
Christon, Philip R.; Meyer, Wallace W.
1989-01-01
Optoelectronic system measures relative angular position of shaft or other device to be turned, also measures absolute angular position after device turned through small angle. Relative angular position measured with fine resolution by optoelectronically counting finely- and uniformly-spaced light and dark areas on encoder disk as disk turns past position-sensing device. Also includes track containing coarsely- and nonuniformly-spaced light and dark areas, angular widths varying in proportion to absolute angular position. This second track provides gating and indexing signal.
Angle of arrival estimation using spectral interferometry
Barber, Z.W.; Harrington, C.; Thiel, C.W.; Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Krishna Mohan, R., E-mail: krishna@spectrum.montana.ed [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)
2010-09-15
We have developed a correlative signal processing concept based on a Mach-Zehnder interferometer and spatial-spectral (S2) materials that enables direct mapping of RF spectral phase as well as power spectral recording. This configuration can be used for precise frequency resolved time delay estimation between signals received by a phased antenna array system that in turn could be utilized to estimate the angle of arrival. We present an analytical theoretical model and a proof-of-principle demonstration of the concept of time difference of arrival estimation with a cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm.
Vaughan, Arthur H. (Inventor)
1993-01-01
A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180 deg strip or arc of a target image. Light received by the spherical mirror section is reflected to a frustoconical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180 deg strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.
Cluster headache or narrow angle glaucoma?
Prasad Palimar
1991-01-01
Full Text Available A 47 year old man with episodes of attacks of pain, redness and mild blurring of vision was investigated for narrow angle glaucoma in view of shallow anterior chambers and a cupped optic disc. The history was reviewed following a spontaneous attack in hospital, which had features other than acute glaucoma. A diagnosis of cluster headache was made on the basis of tests. Cluster headache has been defined as unilateral intense pain, involving the eye and head on one side, usually associated with flushing, nasal congestion and lacrimation; the attacks recurring one or more times daily and lasting 20 - 120 minutes. Such attacks commonly continue for weeks or months and are separated by an asymptomatic period of months to years. This episodic nature, together with unilaterality and tendency to occur at night, closely mimics narrow angle glaucoma. Further, if patients have shallow anterior chambers and disc cupping, the differentiation becomes more difficult yet critical. Resource to provocative tests is often the only answer as the following case report demonstrates.
Hidden topological angles and Lefschetz thimbles
Behtash, Alireza; Schaefer, Thomas; Unsal, Mithat
2015-01-01
We demonstrate the existence of hidden topological angles (HTAs) in a large class of quantum field theories and quantum mechanical systems. HTAs are distinct from theta-parameters in the lagrangian. They arise as invariant angle associated with saddle points of the complexified path integral and their descent manifolds (Lefschetz thimbles). Physical effects of HTAs become most transparent upon analytic continuation in $n_f$ to non-integer number of flavors, reducing in the integer $n_f$ limit to a $\\mathbb Z_2$ valued phase difference between dominant saddles. In ${\\cal N}=1$ super Yang-Mills theory we demonstrate the microscopic mechanism for the vanishing of the gluon condensate. The same effect leads to an anomalously small condensate in a QCD-like $SU(N)$ gauge theory with fermions in the two-index representation. The basic phenomenon is that, contrary to folklore, the gluon condensate can receive both positive and negative contributions in a semi-classical expansion. In quantum mechanics, a HTA leads to ...
Active limited-angle tomographic phase microscope.
Kus, Arkadiusz; Krauze, Wojciech; Kujawinska, Malgorzata
2015-01-01
We demonstrate an active, holographic tomography system, working with limited angle of projections, realized by optical-only, diffraction-based beam steering. The system created for this purpose is a Mach–Zehnder interferometer modified to serve as a digital holographic microscope with a high numerical aperture illumination module and a spatial light modulator (SLM). Such a solution is fast and robust. Apart from providing an elegant solution to viewing angle shifting, it also adds new capabilities of the holographic microscope system. SLM, being an active optical element, allows wavefront correction in order to improve measurement accuracy. Integrated phase data captured with different illumination scenarios within a highly limited angular range are processed by a new tomographic reconstruction algorithm based on the compressed sensing technique: total variation minimization, which is applied here to reconstruct nonpiecewise constant samples. Finally, the accuracy of full measurement and the proposed processing path is tested for a calibrated three-dimensional micro-object as well as a biological object--C2C12 myoblast cell.
determination of determination of optimal tilt angle for maximum ...
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Keywords: Energy output, photovoltaic module, best tilt angle, solar radiation, sunshine hours, ambient temperature. 1. .... at any given time is vital in the design of a PV system. ..... Panels at Different Temperatures and Tilt Angles,”. ISESCO ...
Studying of the Contact Angle Hysteresis on Various Surfaces
Kirichenko E. O.; Gatapova E. Ya.
2016-01-01
This paper is devoted to investigation of the contact angle hysteresis on various surfaces. It was carried out by two different methods: measuring the advancing and the receding contact angles and measuring the contact angles at water droplet evaporation under isothermal conditions. Data obtained using two methods have been compared. The influence of the contact angle hysteresis on the mode of the drop evaporation has been shown.
Studying of the Contact Angle Hysteresis on Various Surfaces
Kirichenko E. O.
2016-01-01
Full Text Available This paper is devoted to investigation of the contact angle hysteresis on various surfaces. It was carried out by two different methods: measuring the advancing and the receding contact angles and measuring the contact angles at water droplet evaporation under isothermal conditions. Data obtained using two methods have been compared. The influence of the contact angle hysteresis on the mode of the drop evaporation has been shown.
A Hydrodynamic Model of Dynamic Contact Angle Hysteresis.
contact angle hysteresis is developed in terms of the interaction of capillary, viscous, and...used to obtain the equations which describe the contact angle region and thereby to define the dynamic contact angle . The analysis is limited to...velocity dependence of the receding contact angle and of the thickness of the deposited film of the receding interface of a wetting liquid are determined as functions of the capillary, viscous, and disjoining forces.
Influence of higher order modes on angled-facet amplifiers
Wang, Z.; Mikkelsen, B.; Stubkjær, Kristian
1991-01-01
The influence of the first-order mode on the residual reflectivity of angled-facet amplifiers is analyzed. For a 7 degrees angled-facet ridge waveguide amplifier with a single-layer antireflective (AR) coating, a gain ripple lower than 1-dB at 25-dB gain can be obtained independent...... by increasing the facet angles to 10 degrees...
Fostering Students' Development of the Concept of Angles Using Technology
Richardson, Sue Ellen; Koyunkaya, Melike Yigit
2017-01-01
We have used "GeoGebra," a dynamic geometry software environment, to explore how Year 4 students understand definitions of angles. Seven students defined angle and then completed several activities adapted for the dynamic environment. Afterward, students again shared their definitions of angles. We found that even a short investigation…
INFLUENCE OF SURFACE-ROUGHNESS ON THE WETTING ANGLE
Zhou, X.B; de Hosson, J.T.M.
1995-01-01
In this paper the influence of surface roughness on contact angles in the system of liquid Al wetting solid surfaces of Al2O3 has been studied. It was observed that contact angles of liquid Al vary significantly on different rough surfaces of Al2O3 A model is proposed to correlate contact angles wit
Surgery for an "Acute Erection Angle," When Counseling Fails
Nugteren, Helena M.; Pascal, Astrid L.; Schultz, Willibrord C. M. Weijmar; van Driel, Mels F.
2010-01-01
Introduction. During erection, the penis increases in volume, rigidity, and angle. Textbooks of urology and sexology provide only very limited information about erection angle dysfunction. In some men, this angle is too tight toward their belly, causing problems with intercourse. Aim. We reported tw
Maximum Atmospheric Entry Angle for Specified Retrofire Impulse
T. N. Srivastava
1969-07-01
Full Text Available Maximum atmospheric entry angles for vehicles initially moving in elliptic orbits are investigated and it is shown that tangential retrofire impulse at the apogee results in the maximum entry angle. Equivalence of maximizing the entry angle and minimizing the retrofire impulse is also established.
Optimal angle reduction - a behavioral approach to linear system approximation
Roorda, Berend; Fuhrmann, P.A.
2001-01-01
We investigate the problem of optimal state reduction under minimization of the angle between system behaviors. The angle is defined in a worst-case sense, as the largest angle that can occur between a system trajectory and its optimal approximation in the reduced-order model. This problem is analyz
Lateral angle: a method for sexing using the petrous bone
Norén, Anna; Lynnerup, Niels; Czarnetzki, Alfred
2005-01-01
We report on the results of applying the so-called lateral angle method for sex determination on skeletal remains. The lateral angle denotes the angle of the internal auditory canal in relation to the medial surface of the petrous part of the temporal bone. The method involves making a small cast...
47 CFR 25.205 - Minimum angle of antenna elevation.
2010-10-01
... 47 Telecommunication 2 2010-10-01 2010-10-01 false Minimum angle of antenna elevation. 25.205... SATELLITE COMMUNICATIONS Technical Standards § 25.205 Minimum angle of antenna elevation. (a) Earth station antennas shall not normally be authorized for transmission at angles less than 5° measured from the...
Surgery for an "Acute Erection Angle," When Counseling Fails
Nugteren, Helena M.; Pascal, Astrid L.; Schultz, Willibrord C. M. Weijmar; van Driel, Mels F.
Introduction. During erection, the penis increases in volume, rigidity, and angle. Textbooks of urology and sexology provide only very limited information about erection angle dysfunction. In some men, this angle is too tight toward their belly, causing problems with intercourse. Aim. We reported
Spray coating of superhydrophobic and angle-independent coloured films.
Ge, Dengteng; Yang, Lili; Wu, Gaoxiang; Yang, Shu
2014-03-07
Angle-independent coloured films with superhydrophobicity were fabricated from quasi-amorphous arrays of monodispersed fluorinated silica nanoparticles via one-step spray coating. The film exhibited a high contact angle (>150°) and a low roll-off angle (~2°) and the colour could be tuned to blue, green and moccasin by varying the size of the nanoparticles.
Zhang, Sai; Zhang, Yu; Gao, Xiao-Wei
2014-12-01
In this paper, superwide-angle acoustic propagations above the critical angles of the Snell law in liquid—solid superlattice are investigated. Incident waves above the critical angles of the Snell law usually inevitably induce total reflection. However, incident waves with big oblique angles through the liquid—solid superlattice will produce a superwide angle transmission in a certain frequency range so that total reflection does not occur. Together with the simulation by finite element analysis, theoretical analysis by using transfer matrix method suggests the Bragg scattering of the Lamb waves as the physical mechanism of acoustic wave super-propagation far beyond the critical angle. Incident angle, filling fraction, and material thickness have significant influences on propagation. Superwide-angle propagation phenomenon may have potential applications in nondestructive evaluation of layered structures and controlling of energy flux.
Xie, Z.Y. (Dept. of Materials Science and Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)); Vailhe, C. (Dept. of Materials Science and Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)); Farkas, D. (Dept. of Materials Science and Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States))
1993-10-01
The atomistic structure of dislocation cores of left angle 111 right angle dislocations in NiAl was simulated using embedded atom method potentials and molecular statics computer simulation. In agreement with previous simulation work and experimental observations, the complete left angle 111 right angle dislocation is stable with respect to the two superpartials of 1/2 left angle 111 right angle separated by an antiphase boundary. The structure of the latter configuration, though metastable, is of interest in the search for ways of improving ductility in this material. The structure of the complete dislocation and that of the metastable superpartials was studied using atomistic computer simulation. An improved visualization method was used for the representation of the resulting structures. The structure of the partials is different from that typical of 1/2 left angle 111 right angle dislocations in b.c.c. materials and that reported previously for the B2 structure using model pair potentials. (orig.)
Distinguishing features of shallow angle plunging jets
Deshpande, Suraj S.; Trujillo, Mario F.
2013-08-01
Numerical simulations employing an algebraic volume-of-fluid methodology are used to study the air entrainment characteristics of a water jet plunging into a quiescent water pool at angles ranging from θ = 10° to θ = 90° measured from the horizontal. Our previous study of shallow angled jets [S. S. Deshpande, M. F. Trujillo, X. Wu, and G. L. Chahine, "Computational and experimental characterization of a liquid jet plunging into a quiescent pool at shallow inclination," Int. J. Heat Fluid Flow 34, 1-14 (2012)], 10.1016/j.ijheatfluidflow.2012.01.011 revealed the existence of a clearly discernible frequency of ingestion of large air cavities. This is in contrast with chaotic entrainment of small air pockets reported in the literature in case of steeper or vertically plunging jets. In the present work, the differences are addressed by first quantifying the cavity size and entrained air volumes for different impingement angles. The results support the expected trend - reduction in cavity size (D43) as θ is increased. Time histories of cavity volumes in the vicinity of the impingement region confirm the visual observations pertaining to a near-periodic ingestion of large air volumes for shallow jets (10°, 12°), and also show that such cavities are not formed for steep or vertical jets. Each large cavity (defined as Dc/Dj ≳ 3) exists in close association with a stagnation point flow. A local mass and momentum balance shows that the high stagnation pressure causes a radial redirection of the jet, resulting in a flow that resembles the initial impact of a jet on the pool. In fact, for these large cavities, their speed matches closely Uimpact/2, which coincides with initial cavity propagation for sufficiently high Froude numbers. Furthermore, it is shown that the approximate periodicity of air entrainment scales linearly with Froude number. This finding is confirmed by a number of simulations at θ = 12°. Qualitatively, for steeper jets, such large stagnation
A superconducting large-angle magnetic suspension
Downer, James R.; Anastas, George V., Jr.; Bushko, Dariusz A.; Flynn, Frederick J.; Goldie, James H.; Gondhalekar, Vijay; Hawkey, Timothy J.; Hockney, Richard L.; Torti, Richard P.
1992-01-01
SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demonstration of the control technology required to develop an advanced momentum exchange effector. The Phase 2 research was directed toward the demonstration for the key technology required for the advanced concept CMG, the controller. The Phase 2 hardware consists of a superconducting solenoid ('source coils') suspended within an array of nonsuperconducting coils ('control coils'), a five-degree-of-freedom positioning sensing system, switching power amplifiers, and a digital control system. The results demonstrated the feasibility of suspending the source coil. Gimballing (pointing the axis of the source coil) was demonstrated over a limited range. With further development of the rotation sensing system, enhanced angular freedom should be possible.
Rare lesions of the cerebellopontine angle.
Yilmaz, Cem; Altinors, Nur; Sonmez, Erkin; Gulsen, Salih; Caner, Hakan
2010-07-01
Vestibular schwannomas, meningiomas and epidermoids account for a vast majority of the lesions occurring in the cerebellopontine angle (CPA). Neoplastic and non-neoplastic pathologies other than these tumors constitute 1% of all lesions located in the CPA. The aim of this study was to reveal our experience in the treatment of the rare lesions of the CPA. We have retrospectively reviewed the medical files and radiological data of all patients who underwent surgery involving any kind of pathology in the CPA. We have excluded those patients with a histopathological diagnosis of meningioma, schwannoma and epidermoids. Our research revealed a case of craniopharyngioma, a case of chloroma, a case of solitary fibrous tumor, a case of pinealoblastoma, a case of atypical teratoid rhabdoid tumor, a case of an aneurysm, a case of hemorrhage and a case of abscess.
Narrow-angle astrometry with PRIMA
Sahlmann, J; Mérand, A; Zimmerman, N; Abuter, R; Chazelas, B; Delplancke, F; Henning, T; Kaminski, A; Köhler, R; Launhardt, R; Mohler, M; Pepe, F; Queloz, D; Quirrenbach, A; Reffert, S; Schmid, C; Schuhler, N; Schulze-Hartung, T
2012-01-01
The Extrasolar Planet Search with PRIMA project (ESPRI) aims at characterising and detecting extrasolar planets by measuring the host star's reflex motion using the narrow-angle astrometry capability of the PRIMA facility at the Very Large Telescope Interferometer. A first functional demonstration of the astrometric mode was achieved in early 2011. This marked the start of the astrometric commissioning phase with the purpose of characterising the instrument's performance, which ultimately has to be sufficient for exoplanet detection. We show results obtained from the observation of bright visual binary stars, which serve as test objects to determine the instrument's astrometric precision, its accuracy, and the plate scale. Finally, we report on the current status of the ESPRI project, in view of starting its scientific programme.
Pneumatic Rotary Actuator Angle Control System
王鹏; 彭光正; 伍清河
2003-01-01
Based on the adaptive control method, a kind of parameter adjustor was used to control pneumatic rotary actuator to track the expected output. The system uses electropneumatic proportional valve as control device, which adjusts the gas flow of actuator 's two cavities, then changes the pressure of cavity and pushes the piston of actuator to move, so the rotary actuator 's axis can be made to revolve to the required angle at last. According to the characteristic of pneumatic system, the control system was described with a fourth-order mathematic model. The control rule is deduced by model reference adaptive control method. By the result of experiment, it was proved that by using the adaptive control method, the output of rotary actuator could track the expected value timely and accurately.
Intrinsic polarization angle ambiguity in Faraday tomography
Kumazaki, Kohei; Ideguchi, Shinsuke; Kurayama, Tomoharu; Takahashi, Keitaro
2014-01-01
Faraday tomography is a powerful method to diagnose polarizations and Faraday rotations along the line of sight. Quality of Faraday tomography is, however, limited by several conditions. Recently, it is reported that Faraday tomography indicates false signals in some specific situations. In this paper, we systematically investigate the condition of the appearance of false signals in Faraday tomography. We study the situations that we observe two sources within a beam, and change the intrinsic polarization angles, rotation measures, intensities, and frequency coverage. We find that false signals arise when rotation measure between the sources is less than 1.5 times the full width at half maximum of the rotation measure spread function. False signals also depend on the intensity ratio between the sources and are reduced for large ratio. On the other hand, the appearance of false signals does not depend on frequency coverage, meaning that the uncertainty should be correctly understood and taken into consideratio...
Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)
Roberts, B.
1986-01-01
The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.
Small angle electron diffraction and deflection
T. Koyama
2012-03-01
Full Text Available Electron optical system is constructed in order to obtain small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 radian in the reciprocal space. Long-distance camera length up to 3000 m is achieved in a conventional transmission electron microscope with LaB6 thermal emission type. The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited in Permalloy elements. A simultaneous recording of electron diffraction and Lorentz deflection is also demonstrated in 180 degree striped magnetic domains of La0.825Sr0.175MnO3.
Sinusoidal Order Estimation Using Angles between Subspaces
Søren Holdt Jensen
2009-01-01
Full Text Available We consider the problem of determining the order of a parametric model from a noisy signal based on the geometry of the space. More specifically, we do this using the nontrivial angles between the candidate signal subspace model and the noise subspace. The proposed principle is closely related to the subspace orthogonality property known from the MUSIC algorithm, and we study its properties and compare it to other related measures. For the problem of estimating the number of complex sinusoids in white noise, a computationally efficient implementation exists, and this problem is therefore considered in detail. In computer simulations, we compare the proposed method to various well-known methods for order estimation. These show that the proposed method outperforms the other previously published subspace methods and that it is more robust to the noise being colored than the previously published methods.
Flow angle from intermediate mass fragment measurements
Rami, F.; Crochet, P.; Dona, R.; De Schauenburg, B.; Wagner, P.; Alard, J.P.; Andronic, A.; Basrak, Z.; Bastid, N.; Belyaev, I.; Bendarag, A.; Berek, G.; Best, D.; Caplar, R.; Devismes, A.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fodor, Z.; Gobbi, A.; Grishkin, Y.; Herrmann, N.; Hildenbrand, K.D.; Hong, B.; Kecskemeti, J.; Kirejczyk, M.; Korolija, M.; Kotte, R.; Lebedev, A.; Leifels, Y.; Merlitz, H.; Mohren, S.; Moisa, D.; Neubert, W.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Plettner, C.; Reisdorf, W.; Schuell, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Stoicea, G.; Stockmeir, M.; Vasiliev, M.; Wisniewski, K.; Wohlfarth, D.; Yushmanov, I.; Zhilin, A
1999-02-15
Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 A MeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anisotropic expanding thermal source, we show that the value at saturation can provide a good estimate of the flow angle, {theta}{sub flow}, in the participant region. It is found that {theta}{sub flow} depends strongly on the impact parameter. The excitation function of {theta}{sub flow} reveals striking deviations from the ideal hydrodynamical scaling. The data exhibit a steep rise of {theta}{sub flow} to a maximum at around 250 - 400 A MeV, followed by a moderate decrease as the bombarding energy increases further.
Angle-resolved cathodoluminescence imaging polarimetry
Osorio, Clara I; Brenny, Benjamin; Polman, Albert; Koenderink, A Femius
2015-01-01
Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the polarization was not fully determined. Here we demonstrate a technique to access the full polarization state of the cathodoluminescence emission, that is the Stokes parameters as a function of the emission angle. Using this technique, we measure the emission of metallic bullseye nanostructures and show that the handedness of the structure as well as nanoscale changes in excitation position induce large changes in polarization ellipticity and helicity. Furthermore, by exploiting the ability of polarimetry to distinguish polarized from unpolarized light, we quantify the contributions of different types of coherent and incoherent radiation to the emission of a gold surface, silicon and gallium arsenide bulk semiconductor...
Wide-angle energy-momentum spectroscopy
Dodson, Christopher M; Li, Dongfang; Zia, Rashid
2014-01-01
Light emission is defined by its distribution in energy, momentum, and polarization. Here, we demonstrate a method that resolves these distributions by means of wide-angle energy-momentum spectroscopy. Specifically, we image the back focal plane of a microscope objective through a Wollaston prism to obtain polarized Fourier-space momentum distributions, and disperse these two-dimensional radiation patterns through an imaging spectrograph without an entrance slit. The resulting measurements represent a convolution of individual radiation patterns at adjacent wavelengths, which can be readily deconvolved using any well-defined basis for light emission. As an illustrative example, we use this technique with the multipole basis to quantify the intrinsic emission rates for electric and magnetic dipole transitions in europium-doped yttrium oxide (Eu$^{3+}$:Y$_{2}$O$_{3}$) and chromium-doped magnesium oxide (Cr$^{3+}$:MgO). Once extracted, these rates allow us to reconstruct the full, polarized, two-dimensional radi...
Disequilibrium dihedral angles in dolerite sills
Holness, Marian B.; Richardson, Chris; Helz, Rosalind T.
2012-01-01
The geometry of clinopyroxene-plagioclase-plagioclase junctions in mafic rocks, measured by the median dihedral angle Θcpp, is created during solidification. In the solidifying Kilauea Iki (Hawaii) lava lake, the wider junctions between plagioclase grains are the first to be filled by pyroxene, followed by the narrower junctions. The final Θcpp, attained when all clinopyroxene-plagioclase-plagioclase junctions are formed, is 78° in the upper crust of the lake, and 85° in the lower solidification front. Θcpp in the 3.5-m-thick Traigh Bhàn na Sgùrra sill (Inner Hebrides) is everywhere 78°. In the Whin Sill (northern England, 38 m thick) and the Portal Peak sill (Antarctica, 129 m thick), Θcpp varies symmetrically, with the lowest values at the margins. The 266-m-thick Basement Sill (Antarctica) has asymmetric variation of Θcpp, attributed to a complex filling history. The chilled margins of the Basement Sill are partially texturally equilibrated, with high Θcpp. The plagioclase grain size in the two widest sills varies asymmetrically, with the coarsest rocks found in the upper third. Both Θcpp and average grain size are functions of model crystallization times. Θcpp increases from 78° to a maximum of ∼100° as the crystallization time increases from 1 to 500 yr. Because the use of grain size as a measure of crystallization time is dependent on an estimate of crystal growth rates, dihedral angles provide a more direct proxy for cooling rates in dolerites.
Mobarak, K A; Espeland, L; Krogstad, O; Lyberg, T
2001-04-01
The objective of this cephalometric study was to compare skeletal stability and the time course of postoperative changes in high-angle and low-angle Class II patients after mandibular advancement surgery. The subjects were 61 consecutive mandibular retrognathism patients whose treatment included bilateral sagittal split osteotomy and rigid fixation. The patients were divided according to the preoperative mandibular plane angle; the 20 patients with the lowest mandibular plane angle (20.8 degrees +/- 4.9 degrees ) constituted the low-angle group, while the 20 cases with the highest mandibular plane angle (43.0 degrees +/- 4.0 degrees ) represented the high-angle group. Lateral cephalograms were taken on 6 occasions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Results demonstrated that the high-angle and low-angle groups had different patterns of surgical and postoperative changes. High-angle patients were associated with both a higher frequency and a greater magnitude of horizontal relapse. While 95% of the total relapse took place during the first 2 months after surgery in the low-angle group, high-angle patients demonstrated a more continuous relapse pattern, with a significant proportion (38%) occurring late in the follow-up period. Possible reasons for the different postsurgical response are discussed.
Investigation of drop dynamic contact angle on copper surface
Orlova, Evgenija; Feoktistov, Dmitriy; Kuznetsov, Geniy
2015-01-01
This paper presents experimental results of the studying the effect of surface roughness, microstructure and flow rate on the dynamic contact angle at spreading of distilled non deaerate water drop on a solid horizontal substrates. Copper substrates with different roughness have been investigated. For each substrate static contact angles depending on volume flow rate have been obtained using shadow system. Increasing the volume flow rate resulted in an increase of the static contact angle. It was found that with increasing surface roughness dynamic contact angle arises. Also difference in formation of the equilibrium contact angle at low and high rates of drop growth has been detected.
Development of a Contact Angle Measurement Method Based Upon Geometry
Kim, Dong Su; Pyo, Na Young; Seo, Seung Hee [Ewha Womans University, Seoul (Korea); Choi, Woo Jin [Suwon University, Suwon (Korea); Kwon, Young Shik [Suwon Science College, Suwon (Korea)
1998-12-31
A new way of contact angle measurement is derived based on simple geometrical calculation. Without using complicated contact angle measurement instrument, just measuring the diameter and height of liquid lens made it possible to calculate the contact angle value with a reasonable reliability. To validate the contact angle value obtained by this method, contact angle of the same liquid lens is measured using conventional goniometer and it is verified that two values are nearly same within the limit of observational error. (author). 6 refs., 2 tabs., 3 figs.
Absolute small-angle measurement based on optical feedback interferometry
Jingang Zhong; Xianhua Zhang; Zhixiang Ju
2008-01-01
We present a simple but effective method for small-angle measurement based on optical feedback inter-ferometry (or laser self-mixing interferometry). The absolute zero angle can be defined at the biggest fringe amplitude point, so this method can also achieve absolute angle measurement. In order to verify the method, we construct an angle measurement system. The Fourier-transform method is used to analysis the interference signal. Rotation angles are experimentally measured with a resolution of 10-6 rad and a measurement range of approximately from -0.0007 to +0.0007 rad.
Optimal relative view angles for an object viewed multiple times
Gilani, Syed U.; Shende, Apoorva; Nguyen, Bao; Stilwell, Daniel J.
2015-05-01
Typically, the detection of an object of interest improves as we view the object from multiple angles. For cases where viewing angle matters, object detection can be improved further by optimally selecting the relative angles of multiple views. This motivates the search for viewing angles that maximize the expected probability of detection. Although our work is motivated by applications in subsea sensing, our fundamental analysis is easily adapted for other classes of applications. The specific challenge that motivates our work is the selection of optimal viewing angles for subsea sensing in which sonar is used for bathymetric imaging.
Measurement of dihedral angles by scanning electron microscopy.
Achutaramayya, G.; Scott, W. D.
1973-01-01
The extension of Hoover's (1971) technique to the case of dihedral-angle measurement is described. Dihedral angles are often determined by interferometry on thermally grooved grain boundaries to obtain information on relative interfacial energies. In the technique considered the measured angles approach the true angles as the tilt angle approaches 90 deg. It is pointed out that the scanning electron microscopy method provides a means of seeing the real root of a groove at a lateral magnification which is higher than that obtainable with interferometry.
Rates of solar angles for two-axis concentrators
Yung, C. S.; Lansing, F. L.
1982-01-01
The Sun's position by the azimuth and elevation angles and its rate of change at any time of day are determined to design 2 axis tracking mechanisms of solar concentrators. The Sun's angles and their rates for selected months of the year (March, June, September and December) and for seven selected atitudes (0, + or - 30, + or - 60, + or - 90) covering both the northern and southern hemispheres were studied. The development of the angle and angle rate analytical expressions for any month, hour of day, and latitude provides the solar concentrator designer with a quantitative determination of the limiting Sun's position and angle rates for an accurate automatic tracking mechanism.
Investigation of drop dynamic contact angle on copper surface
Orlova Evgenija
2015-01-01
Full Text Available This paper presents experimental results of the studying the effect of surface roughness, microstructure and flow rate on the dynamic contact angle at spreading of distilled non deaerate water drop on a solid horizontal substrates. Copper substrates with different roughness have been investigated. For each substrate static contact angles depending on volume flow rate have been obtained using shadow system. Increasing the volume flow rate resulted in an increase of the static contact angle. It was found that with increasing surface roughness dynamic contact angle arises. Also difference in formation of the equilibrium contact angle at low and high rates of drop growth has been detected.
Scattering angle-based filtering via extension in velocity
Kazei, Vladimir
2016-09-06
The scattering angle between the source and receiver wavefields can be utilized in full-waveform inversion (FWI) and in reverse-time migration (RTM) for regularization and quality control or to remove low frequency artifacts. The access to the scattering angle information is costly as the relation between local image features and scattering angles has non-stationary nature. For the purpose of a more efficient scattering angle information extraction, we develop techniques that utilize the simplicity of the scattering angle based filters for constantvelocity background models. We split the background velocity model into several domains with different velocity ranges, generating an
Measurement of dihedral angles by scanning electron microscopy.
Achutaramayya, G.; Scott, W. D.
1973-01-01
The extension of Hoover's (1971) technique to the case of dihedral-angle measurement is described. Dihedral angles are often determined by interferometry on thermally grooved grain boundaries to obtain information on relative interfacial energies. In the technique considered the measured angles approach the true angles as the tilt angle approaches 90 deg. It is pointed out that the scanning electron microscopy method provides a means of seeing the real root of a groove at a lateral magnification which is higher than that obtainable with interferometry.
Dilemma of gonial angle measurement: Panoramic radiograph or lateral cephalogram
Radhakrishnan, Pillai Devu; Varma, Nilambur Kovilakam Sapna; Ajith, Vallikat Velath [Dept. of Orthodontics, Amrita School of Dentistry, Kochi (India)
2017-06-15
The purpose of this study was to evaluate the accuracy of panoramic imaging in measuring the right and left gonial angles by comparing the measured angles with the angles determined using a lateral cephalogram of adult patients with class I malocclusion. The gonial angles of 50 class I malocclusion patients (25 males and 25 females; mean age: 23 years) were measured using both a lateral cephalogram and a panoramic radiograph. In the lateral cephalograms, the gonial angle was measured at the point of intersection of the ramus plane and the mandibular plane. In the panoramic radiographs, the gonial angle was measured by drawing a line tangent to the lower border of the mandible and another line tangent to the distal border of the ascending ramus and the condyle on both sides. The data obtained from both radiographs were statistically compared. No statistically significant difference was observed between the gonial angle measured using the lateral cephalograms and that determined using the panoramic radiographs. Further, there was no statistically significant difference in the measured gonial angle with respect to gender. The results also showed a statistically insignificant difference in the mean of the right and the left gonial angles measured using the panoramic radiographs. As the gonial angle measurements using panoramic radiographs and lateral cephalograms showed no statistically significant difference, panoramic radiography can be considered in orthodontics for measuring the gonial angle without any interference due to superimposed images.
Impacts of tropical cyclone inflow angle on ocean surface waves
ZHAO Wei; HONG Xin
2011-01-01
The inflow angle of tropical cyclones (TC) is generally neglected in numerical studies of ocean surface waves induced by TC. In this study, the impacts of TC inflow angle on ocean surface waves were investigated using a high-resolution wave model. Six numerical experiments were conducted to examine, in detail, the effects of inflow angle on mean wave parameters and the spectrum of wave directions. A comparison of the waves simulated in these experiments shows that inflow angle significantly modifies TC-induced ocean surface waves. As the inflow angle increases, the asymmetric axis of the significant wave height (SWH) field shifts 30° clockwise, and the maximum SWH moves from the front-right to the rear-right quadrant. Inflow angle also affects other mean wave parameters, especially in the rear-left quadrant, such as the mean wave direction, the mean wavelength, and the peak direction. Inflow angle is a key factor in wave models for the reproduction of double-peak or multi-peak patterns in the spectrum of wave directions. Sensitivity experiments also show that the simulation with a 40° inflow angle is the closest to that of the NOAA statistical SLOSH inflow angle. This suggests that 40° can be used as the inflow angle in future TC-induced ocean surface wave simulations when SLOSH or observed inflow angles are not available.
A robust polynomial fitting approach for contact angle measurements.
Atefi, Ehsan; Mann, J Adin; Tavana, Hossein
2013-05-14
Polynomial fitting to drop profile offers an alternative to well-established drop shape techniques for contact angle measurements from sessile drops without a need for liquid physical properties. Here, we evaluate the accuracy of contact angles resulting from fitting polynomials of various orders to drop profiles in a Cartesian coordinate system, over a wide range of contact angles. We develop a differentiator mask to automatically find a range of required number of pixels from a drop profile over which a stable contact angle is obtained. The polynomial order that results in the longest stable regime and returns the lowest standard error and the highest correlation coefficient is selected to determine drop contact angles. We find that, unlike previous reports, a single polynomial order cannot be used to accurately estimate a wide range of contact angles and that a larger order polynomial is needed for drops with larger contact angles. Our method returns contact angles with an accuracy of contact angles in a wide range with a fourth-order polynomial. We show that this approach returns dynamic contact angles with less than 0.7° error as compared to ADSA-P, for the solid-liquid systems tested. This new approach is a powerful alternative to drop shape techniques for estimating contact angles of drops regardless of drop symmetry and without a need for liquid properties.
Surgery for an "acute erection angle," when counseling fails.
Nugteren, Helena M; Pascal, Astrid L; Weijmar Schultz, Willibrord C M; van Driel, Mels F
2010-03-01
During erection, the penis increases in volume, rigidity, and angle. Textbooks of urology and sexology provide only very limited information about erection angle dysfunction. In some men, this angle is too tight toward their belly, causing problems with intercourse. We reported two cases of an acute erection angle and reviewed pertinent literature. Comprehensive literature review was performed using PubMed. We performed additional searches based on relevant books. There is very limited knowledge about erection angles and the "acute erection angle." Our cases show that simple and safe surgical techniques can yield adequate results. Counseling a couple with complaints of sexual inadequacy, which has resulted specifically from the increased erection angle, should be based on objective reassuring information about anatomical and physiological facts. In selected cases surgical intervention can yield adequate results.
Shinoj, V. K.; Murukeshan, V. M.; Baskaran, M.; Aung, T.
2014-06-01
Noninvasive medical imaging techniques have high potential in the field of ocular imaging research. Angle closure glaucoma is a major disease causing blindness and a possible way of detection is the examination of the anterior chamber angle in eyes. Here, a simple optical method for the evaluation of angle-closure glaucoma is proposed and illustrated. The light propagation from the region associated with the iridocorneal angle to the exterior of eye is considered analytically. The design of the gel assisted probe prototype is carried out and the imaging of iridocorneal angle is performed on an eye model.
Conservative compensatory Angle Class III malocclusion treatment
Marcio Costa Sobral
2012-12-01
Full Text Available INTRODUCTION: Angle's Class III malocclusion is a dental discrepancy in a sagittal view that may appear or not with an important skeletal discrepancy. Facial esthetics may be affected by this skeletal discrepancy and it is one of the most common complaints of patients who seek orthodontic treatment. Class III treatment, in adults, may be done by compensatory tooth movement, in simple cases, or through an association between orthodontics and orthognathic surgery, in more severe cases. OBJECTIVE: This article describes a non-extraction compensatory Class III treatment case, applying the Tweed-Merrifield mechanical principles with headgear (J-Hook in the mandibular arch. This case was presented at the V Brazilian Association of Orthodontics and Dentofacial Orthopedics (ABOR Meeting, it was evaluated by members of Brazilian Board of Orthodontics and obtained third place in the general classification.INTRODUÇÃO: a má oclusão de Classe III se caracteriza por uma desarmonia dentária anteroposterior, podendo estar ou não acompanhada por discrepâncias esqueléticas. A estética facial pode se apresentar comprometida, em maior ou menor grau, a depender da magnitude da discrepância, constituindo um dos principais fatores motivadores da procura por tratamento ortodôntico. O tratamento da Classe III em pacientes adultos pode ser realizado mediante compensação dentária, nos casos mais simples, ou, em situações mais severas, mediante a associação entre Ortodontia e Cirurgia Ortognática. OBJETIVO: o presente artigo objetiva relatar um caso clínico caracterizado por uma má oclusão de Classe III de Angle, tratado de forma compensatória, com extração dos terceiros molares inferiores, mediante a utilização de aparelhagem extrabucal na arcada inferior (J-hook, aplicando-se princípios da técnica de Tweed-Merrifield. Esse caso foi apresentado no 5º Congresso da Associação Brasileira de Ortodontia e Ortopedia Facial (ABOR, na categoria
Bai,M.; Ptitsyn, V.; Roser, T.
2008-10-01
To keep the spin tune in the spin depolarizing resonance free region is required for accelerating polarized protons to high energy. In RHIC, two snakes are located at the opposite side of each accelerator. They are configured to yield a spin tune of 1/2. Two pairs of spin rotators are located at either side of two detectors in each ring in RHIC to provide longitudinal polarization for the experiments. Since the spin rotation from vertical to longitudinal is localized between the two rotators, the spin rotators do not change the spin tune. However, due to the imperfection of the orbits around the snakes and rotators, the spin tune can be shifted. This note presents the impact of the horizontal orbital angle between the two snakes on the spin tune, as well as the effect of the vertical orbital angle between two rotators at either side of the collision point on the spin tune.
The correlation of multi-angle thermal infrared data and the choice of optimal view angles
FAN; Wenjie; XU; Xiru
2004-01-01
Based on the matrix formula of thermal infrared radiant system, the components temperature can be retrieved by the inversive matrix. Around the stability problem of retrieved result, the research work we did was focused on (i) the correlation of (wk,j) which is the key to affect the retrieval accuracy, (ii) a general method which can help us find the number of retrievable parameters and evaluate the retrieval error before its performance, (iii) the choice of "optimal viewing angle group" based on the formula of absolute error propagation. The row winter wheat field was chosen as an example. The results can provide a theoretical basis for multi-angle thermal infrared remote sensing and components temperature retrieval.
Lam, C N C; Wu, R; Li, D; Hair, M L; Neumann, A W
2002-02-25
Two types of experiments were used to study the behavior of both advancing and receding contact angles, namely the dynamic one-cycle contact angle (DOCA) and the dynamic cycling contact angle (DCCA) experiments. For the preliminary study, DOCA measurements of different liquids on different solids were performed using an automated axisymmetric drop shape analysis-profile (ADSA-P). From these experimental results, four patterns of receding contact angle were observed: (1) time-dependent receding contact angle; (2) constant receding contact angle; (3) 'stick/slip'; (4) no receding contact angle. For the purpose of illustration, results from four different solid surfaces are shown. These solids are: FC-732-coated surface; poly(methyl methacrylate/n-butyl methacrylate) [P(MMA/nBMA)]; poly(lactic acid) (DL-PLA); and poly(lactic/glycolic acid) 50/50 (DL-PLGA 50/50). Since most of the surfaces in our studies exhibit time dependence in the receding contact angle, a more extended study was conducted using only FC-732-coated surfaces to better understand the possible causes of decreasing receding contact angle and contact angle hysteresis. Contact angle measurements of 21 liquids from two homologous series (i.e. n-alkanes and 1-alcohols) and octamethylcyclotetrasiloxane (OCMTS) on FC-732-coated surfaces were performed. It is apparent that the contact angle hysteresis decreases with the chain length of the liquid. It was found that the receding contact angle equals the advancing angle when the alkane molecules are infinitely large. These results strongly suggest that the chain length and size of the liquid molecule could contribute to contact angle hysteresis phenomena. Furthermore, DCCA measurements of six liquids from the two homologous series on FC-732-coated surfaces were performed. With these experimental results, one can construe that the time dependence of contact angle hysteresis on relatively smooth and homogeneous surfaces is mainly caused by liquid retention
Mapping of low flip angles in magnetic resonance
Balezeau, Fabien; Saint-Jalmes, Herve [LTSI, INSERM U642, Universite Rennes 1 (France); Eliat, Pierre-Antoine [PRISM, IFR 140, Universite Rennes 1 (France); Cayamo, Alejandro Bordelois, E-mail: fabien.balezeau@gmail.com [Centro De BiofIsika Medica, Universidad de Oriente, Santiago de Cuba (Cuba)
2011-10-21
Errors in the flip angle have to be corrected in many magnetic resonance imaging applications, especially for T1 quantification. However, the existing methods of B1 mapping fail to measure lower values of the flip angle despite the fact that these are extensively used in dynamic acquisition and 3D imaging. In this study, the nonlinearity of the radiofrequency (RF) transmit chain, especially for very low flip angles, is investigated and a simple method is proposed to accurately determine both the gain of the RF transmitter and the B1 field map for low flip angles. The method makes use of the spoiled gradient echo sequence with long repetition time (TR), such as applied in the double-angle method. It uses an image acquired with a flip angle of 90{sup 0} as a reference image that is robust to B1 inhomogeneity. The ratio of the image at flip angle alpha to the image at a flip angle of 90{sup 0} enables us to calculate the actual value of alpha. This study was carried out at 1.5 and 4.7 T, showing that the linearity of the RF supply system is highly dependent on the hardware. The method proposed here allows us to measure the flip angle from 1{sup 0} to 60{sup 0} with a maximal uncertainty of 10% and to correct T1 maps based on the variable flip angle method.
Numerical aperture characteristics of angle-ended plastic optical fiber
Gao, Cheng; Farrell, Gerard
2003-03-01
With the increasing information rates demanded in consumer, automotive and aeronautical applications, a low cost and high performance physical transmission medium is required. Compared with Silica Optical Fiber, Plastic Optical Fiber (POF) offers an economic solution for a range of high-capacity, short-haul applications in industrial and military environments. Recently, a new type of POF, the perfluorinated graded-index plastic optical fiber (PF GI-POF), has been introduced that has low losses and high bandwidth at the communication wavelengths 850 nm and 1300nm. POF is normally terminated perpendicular to the fiber axis. We propose an angle-ended POF, which is terminated at non-perpendicular angles to the fiber axis. The aim of the research is to investigate the numerical aperture (NA) characteristics of angle-ended POF along the major axis of the elliptical endface. A theoretical model indicates that the NA of the angle-ended POF will increase nonlinearly with tilt-angle and the acceptance cone will be deflected with the angle of the deflection increasing nonlinearly with tilt-angle. We present results for the measured NA and the measured deflection angle using the far-field radiation method. Results are presented for 13 angle-ended SI-POF tilt-angles. We also present results for theoretical value of NA and deflection angle as a function of tilt-angle. The agreement between the measured and theoretical value is good up to tilt-angles of about 15 degrees, beyond which deviation occurs.
徐海栋; 陈勇; 赵建宁
2013-01-01
BACKGROUND: Treatments for hal ux valgus are diverse. Mini double thread hol ow screw combined with osteotomy surgery is a smal invasive surgery, which can meet the orthopedic purpose of hal ux valgus and can be considered as the new minimal y invasive biological fixation material in clinic. OBJECTIVE: To retrospectively analyze the curative effect of mini double-thread hol ow screw combined with osteotomy for the treatment of hal ux valgus. METHODS: Thirty patients with hal ux valgus (eight patients with bilateral orthopedic operation and 22 patients with unilateral orthopedic operation) were selected and treated with the first metatarsal osteotomy combined with mini double-thread hol ow screw internal fixation according to the wil ingness of the patients. The X-ray films were taken before and after operation to compare the hal ux valgus angle, intermetatarsal angle, sesamoides position and the American Orthopedic Foot and Ankle Society Ankle Hindfoot Scale score. And the shortening length of first metatarsal bone was calculated.RESULTS AND CONCLUSION: Hal ux valgus angle, intermetatarsal angle, sesamoides position and American Orthopaedic Foot and Ankle Society Ankle Hindfoot Scale score post-operation were improved obviously compared with those pre-operation. The shortening length of the first metatarsal bone was in orthopedic control able scope, thereby avoiding deformity recurrence and metatarsus pain.% 背景：拇外翻畸形矫正方式多样，采用迷你双螺纹空心钉材料结合截骨矫形的方式损伤小，能够满足拇外翻矫形的目的，是临床上新型的微创生物型内固定材料。目的：回顾性分析迷你双螺纹空心钉材料应用于截骨矫形拇外翻治疗中的临床疗效。方法：选择拇外翻畸形患者30例，其中双侧矫形患者8例，单侧矫形患者22例。根据自愿均采用第一跖骨截骨矫形迷你双螺纹空心钉内固定，治疗前后拍摄 X 射线片测量外翻角、跖间
Neutron elastic scattering at very small angles
2002-01-01
This experiment will measure neutron-proton elastic scattering at very small angles and hence very small four-momentum transfer, |t|. The range of |t| depends on the incident neutron momentum of the events but the geometrical acceptance will cover the angular range 0.025 < $\\Theta_{lab}$ < 1.9 mrad. The higher figure could be extended to 8.4 mrad by changing the geometry of the experiment in a later phase. \\\\ \\\\ The neutron beam will be highly collimated and will be derived from a 400 GeV external proton beam of up to $4 \\times 10^{10}$ protons per pulse in the SPS North Area Hall 1. The hydrogen target will be gaseous, operating at 40 atm. pressure and acts as a multiwire proportional chamber to detect the recoil protons. The forward neutron will be detected and located by interaction in a neutron vertex detector and its energy measured by a conventional steel plate calorimeter. \\\\ \\\\ The experiment will cover the angular region of nucleon-nucleon scattering which is dominated by Coulomb scattering ...
Angle resolved photoemission spectroscopy and surface states
Kar, Nikhiles
2016-10-01
Angle Resolved Photo Emission Spectroscopy (ARPES) has been a very effective tool to study the electronic states of solids, from simple metals to complex systems like cuprate superconductors. For photon energy in the range of 10 - 100 eV, it is a surface sensitive process as the free path of the photo emitted electrons is of the order of a few lattice parameters. However to interpret the experimental data one needs to have a theoretical foundation for the photoemission process. From the theory of photoemission it may be seen that one can get information about the state from which the electron has been excited. As the translational periodicity is broken normal to the surface, a new type of electron state in the forbidden energy gap can exist localized in the surface region. ARPES can reveal the existence and the property of such surface states. We shall also discuss briefly how the electromagnetic field of the photons are influenced by the presence of the surface and how one can try to take that into account in photoemission theory.
Impact Angle Control of Interplanetary Shock Geoeffectiveness
Oliveira, D M
2015-01-01
We use OpenGGCM global MHD simulations to study the nightside magnetospheric, magnetotail, and ionospheric responses to interplanetary (IP) fa st forward shocks. Three cases are presented in this study: two inclined oblique shocks, here after IOS-1 and IOS-2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30$^o$ in relation to the Sun-Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along the Sun-Earth line, with the same Mach number as IOS-1. We find that, in the IOS-1 case, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the FPS compresses the magnetotail from both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in stronger...
Rubber hand illusion affects joint angle perception.
Martin V Butz
Full Text Available The Rubber Hand Illusion (RHI is a well-established experimental paradigm. It has been shown that the RHI can affect hand location estimates, arm and hand motion towards goals, the subjective visual appearance of the own hand, and the feeling of body ownership. Several studies also indicate that the peri-hand space is partially remapped around the rubber hand. Nonetheless, the question remains if and to what extent the RHI can affect the perception of other body parts. In this study we ask if the RHI can alter the perception of the elbow joint. Participants had to adjust an angular representation on a screen according to their proprioceptive perception of their own elbow joint angle. The results show that the RHI does indeed alter the elbow joint estimation, increasing the agreement with the position and orientation of the artificial hand. Thus, the results show that the brain does not only adjust the perception of the hand in body-relative space, but it also modifies the perception of other body parts. In conclusion, we propose that the brain continuously strives to maintain a consistent internal body image and that this image can be influenced by the available sensory information sources, which are mediated and mapped onto each other by means of a postural, kinematic body model.
Apparent contact angle of an evaporating drop
Morris, S. J. S.
2012-11-01
In experiments by Poulard et al. (2005), a sessile drop of perfectly wetting liquid evaporates from a non-heated substrate into an under-saturated mixture of vapour with an inert gas; evaporation is limited by vapour diffusion. The system exhibits an apparent contact angle θ that is a flow property. Under certain conditions, the apparent contact line was stationary relative to the substrate; we predict θ for this case. Observed values of θ are small, allowing lubrication analysis of the liquid film. The liquid and vapour flows are coupled through conditions holding at the phase interface; in particular, vapour partial pressure there is related to the local value of liquid pressure through the Kelvin condition. Because the droplet is shallow, the interfacial conditions can be transferred to the solid-liquid interface at y = 0 . We show that the dimensionless partial pressure p (x , y) and the film thickness h (x) are determined by solving ∇2 p = 0 for y > 0 subject to a matching condition at infinity, and the conditions - p = L hxx +h-3 and (h3px) x + 3py = 0 at y = 0 . The parameter L controls the ratio of Laplace to disjoining pressure. We analyse this b.v.p. for the experimentally-relevant case L --> 0 .
Small angle diffraction imaging for disease diagnosis
Wilkinson, S.J. [Department of Materials and Medical Sciences, Cranfield University, Shrivenham, Swindon, Wiltshire SN6 8LA (United Kingdom)]. E-mail: s.j.wilkinson@dl.ac.uk; Rogers, K.D. [Department of Materials and Medical Sciences, Cranfield University, Shrivenham, Swindon, Wiltshire SN6 8LA (United Kingdom); Hall, C.J. [Darebury Research Laboratory, Keckwick Lane, Warrington, Cheshire, WA4 4AD (United Kingdom); Lewis, R.A. [Monash University, Melbourne, Victoria (Australia); Round, A. [Darebury Research Laboratory, Keckwick Lane, Warrington, Cheshire, WA4 4AD (United Kingdom); Pinder, S.E. [Nottingham City Hospital, Nottingham (United Kingdom); Boggis, C. [Withington Hospital, Manchester (United Kingdom); Hufton, A. [Christie Hospital, Manchester (United Kingdom)
2005-08-11
Current work in small angle X-ray scattering (SAXS) as a means of determining the disease state of tissue biopsy samples is showing encouraging results. Statistical analyses of SAXS patterns have identified components of the data which correlate well with the presence or absence of cancer in breast tissue. A study has now been started which attempts to create images of macroscopic scale samples using this information. One way of building up a two-dimensional map of this SAXS information on such a sample would be to raster scan a small X-ray beam. However, the time taken to perform such a scan is likely to make this technique impractical, especially if it would be considered for use in a clinical environment. Some initial work using a wide, thin X-ray beam, has shown that it is possible to deconvolve a model SAXS pattern from the smeared out SAXS pattern and is verified using slightly modified methods. Three distinct tissue types were successfully distinguished and imaged from a single scan of the beam. We are continuing this work by building a more sophisticated phantom and using a higher quality SAXS facility on the SRS in the UK. The results of the first steps towards disease specific imaging are presented. The possibility of making tomographic SAXS images is also being pursued. Techniques for data analysis on SAXS from blocks of tissues are discussed.
Small angle diffraction imaging for disease diagnosis
Wilkinson, S. J.; Rogers, K. D.; Hall, C. J.; Lewis, R. A.; Round, A.; Pinder, S. E.; Boggis, C.; Hufton, A.
2005-08-01
Current work in small angle X-ray scattering (SAXS) as a means of determining the disease state of tissue biopsy samples is showing encouraging results. Statistical analyses of SAXS patterns have identified components of the data which correlate well with the presence or absence of cancer in breast tissue. A study has now been started which attempts to create images of macroscopic scale samples using this information. One way of building up a two-dimensional map of this SAXS information on such a sample would be to raster scan a small X-ray beam. However, the time taken to perform such a scan is likely to make this technique impractical, especially if it would be considered for use in a clinical environment. Some initial work using a wide, thin X-ray beam, has shown that it is possible to deconvolve a model SAXS pattern from the smeared out SAXS pattern and is verified using slightly modified methods. Three distinct tissue types were successfully distinguished and imaged from a single scan of the beam. We are continuing this work by building a more sophisticated phantom and using a higher quality SAXS facility on the SRS in the UK. The results of the first steps towards disease specific imaging are presented. The possibility of making tomographic SAXS images is also being pursued. Techniques for data analysis on SAXS from blocks of tissues are discussed.
Magic angle spinning NMR of paramagnetic proteins.
Knight, Michael J; Felli, Isabella C; Pierattelli, Roberta; Emsley, Lyndon; Pintacuda, Guido
2013-09-17
Metal ions are ubiquitous in biochemical and cellular processes. Since many metal ions are paramagnetic due to the presence of unpaired electrons, paramagnetic molecules are an important class of targets for research in structural biology and related fields. Today, NMR spectroscopy plays a central role in the investigation of the structure and chemical properties of paramagnetic metalloproteins, linking the observed paramagnetic phenomena directly to electronic and molecular structure. A major step forward in the study of proteins by solid-state NMR came with the advent of ultrafast magic angle spinning (MAS) and the ability to use (1)H detection. Combined, these techniques have allowed investigators to observe nuclei that previously were invisible in highly paramagnetic metalloproteins. In addition, these techniques have enabled quantitative site-specific measurement of a variety of long-range paramagnetic effects. Instead of limiting solid-state NMR studies of biological systems, paramagnetism provides an information-rich phenomenon that can be exploited in these studies. This Account emphasizes state-of-the-art methods and applications of solid-state NMR in paramagnetic systems in biological chemistry. In particular, we discuss the use of ultrafast MAS and (1)H-detection in perdeuterated paramagnetic metalloproteins. Current methodology allows us to determine the structure and dynamics of metalloenzymes, and, as an example, we describe solid-state NMR studies of microcrystalline superoxide dismutase, a 32 kDa dimer. Data were acquired with remarkably short times, and these experiments required only a few milligrams of sample.
Moderate positive spin Hall angle in uranium
Singh, Simranjeet; Anguera, Marta; Barco, Enrique del, E-mail: delbarco@ucf.edu, E-mail: cwmsch@rit.edu [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Springell, Ross [H. H. Will Laboratory, University of Bristol, Bristol BS2 8BS (United Kingdom); Miller, Casey W., E-mail: delbarco@ucf.edu, E-mail: cwmsch@rit.edu [School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, New York 14623 (United States)
2015-12-07
We report measurements of spin pumping and the inverse spin Hall effect in Ni{sub 80}Fe{sub 20}/uranium bilayers designed to study the efficiency of spin-charge interconversion in a super-heavy element. We employ broad-band ferromagnetic resonance on extended films to inject a spin current from the Ni{sub 80}Fe{sub 20} (permalloy) into the uranium layer, which is then converted into an electric field by the inverse spin Hall effect. Surprisingly, our results suggest a spin mixing conductance of order 2 × 10{sup 19} m{sup −2} and a positive spin Hall angle of 0.004, which are both merely comparable with those of several transition metals. These results thus support the idea that the electronic configuration may be at least as important as the atomic number in governing spin pumping across interfaces and subsequent spin Hall effects. In fact, given that both the magnitude and the sign are unexpected based on trends in d-electron systems, materials with unfilled f-electron orbitals may hold additional exploration avenues for spin physics.
Magnetic resonance imaging of cerebellopontine angle lesions
Pratiksha Yadav
2015-01-01
Full Text Available Background: Cerebellopontine angle (CPA tumors are usually benign, and they are divided into extra-axial, intra-axial, extradural, and petrous axis tumors. CPA pathologies can be asymptomatic or it may present with vertigo, tinnitus, or unilateral hearing loss depending upon the site of tumor origin and displacement of the neurovascular structure. Aim and Objectives: To evaluate the role of magnetic resonance imaging (MRI aided with contrast-enhanced MRI as an imaging modality for diagnosis of CPA lesions. Materials and Methods: Analysis of 36 patients of CPA lesions over a period of 2 years was done. MRI was performed on Siemens 1.5 Tesla MAGNETOM Avanto Machine. Conclusion: There are spectrums of pathologies, which can present with these symptoms, which includes tumors, vascular malformations, and vascular loop compressing vestibulocochlear nerve or mastoid pathology so it is important to investigate the patient by MRI. Contrast-enhanced MRI is the most sensitive investigation in the evaluation of the CPA lesions, its characteristic, and its extent.
The traction angle and cervical intervertebral separation.
Wong, A M; Leong, C P; Chen, C M
1992-02-01
Seventeen normal young adults were evaluated for cervical intervertebral separation under different traction angles through motorized intermittent traction in the supine position. In all cases, the anterior and posterior intervertebral spaces were increased by traction at neutral position and in 30 degrees flexion, but not in 15 degrees extension. The effects of separation were 1) neutral position: anterior intervertebral separation C4-5 (12%) greater than C3-4 (8%), posterior intervertebral separation C6-7 (37%) greater than C3-4 (22%) greater than C4-5 (19%); and 2) 30 degrees flexion: anterior intervertebral separation C2-3 (21%) greater than C4-5 (16%) greater than C5-6 (15%) greater than C3-4 (10%), posterior intervertebral separation C6-7 (20%) greater than C5-6 (19%) greater than C4-5 (17%). There was a significant decrease in intervertebral separation posteriorly in extension traction, especially at C6-7 (-50%), C5-6 (-37%), C4-5 (-26%), and C3-4 (-14%). The separation of facet joint surfaces was found after traction at 15 degrees extension, but not in the neutral or flexion positions.
NMR probe for dynamic-angle spinning
Mueller, K. T.; Chingas, G. C.; Pines, A.
1991-06-01
We describe the design of a probe for dynamic-angle spinning (DAS) NMR experiments, comprised of a spinning cylindrical sample holder whose axis may be reoriented rapidly between discrete directions within the bore of a superconducting magnet. This allows the refocusing of nuclear spin magnetization that evolves under anisotropic interactions such as chemical shift anisotropy and quadrupolar coupling, providing high resolution NMR spectra for quadrupolar nuclei in solid materials. The probe includes an axial air delivery system to bearing and drive jets which support and spin a rotor containing the sample. Axis reorientation is accomplished with a pulley attached to the probehead and coupled to a stepping motor outside of the magnet. The choice of motor and gear ratio is based on an analysis of the moments of inertia of the motor and load, the desired angular resolution, and simplicity of design. Control of angular accuracy and precision are discussed, as well as the efficiency of radiofrequency irradiation and detection. High resolution DAS spectra of oxygen-17 and aluminum-27 nuclei in polycrystalline minerals illustrate the experimental capabilities.
Perturbative estimates of lepton mixing angles in unified models
Antusch, Stefan [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Muenchen (Germany)], E-mail: antusch@mppmu.mpg.de; King, Stephen F. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Malinsky, Michal [Department of Theoretical Physics, School of Engineering Sciences, Royal Institute of Technology (KTH) - AlbaNova University Center, Roslagstullsbacken 21, SE-106 91 Stockholm (Sweden)
2009-10-11
Many unified models predict two large neutrino mixing angles, with the charged lepton mixing angles being small and quark-like, and the neutrino masses being hierarchical. Assuming this, we present simple approximate analytic formulae giving the lepton mixing angles in terms of the underlying high energy neutrino mixing angles together with small perturbations due to both charged lepton corrections and renormalisation group (RG) effects, including also the effects of third family canonical normalization (CN). We apply the perturbative formulae to the ubiquitous case of tri-bimaximal neutrino mixing at the unification scale, in order to predict the theoretical corrections to mixing angle predictions and sum rule relations, and give a general discussion of all limiting cases. We also discuss the implications for the sum rule relations of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.
Study of the course of the incidence angle during growth.
Mangione, P; Gomez, D; Senegas, J
1997-01-01
Standing posture is made possible by hip extension and lumbar lordosis. Lumbar lordosis is correlated with pelvic parameters, such as the declivity angle of the upper surface of the sacrum and the incidence angle, which determine the sagittal morphotype. Incidence angle, which is different for each individual, is known to be very important for up-right posture, but its course during life has not yet been established. Incidence angle was measured on radiographs of 30 fetuses, 30 children and 30 adults, and results were analysed using the correlation coefficient r and Student's t test. A statistically significant correlation between age and incidence angle was observed. Incidence angle considerably increases during the first months, continues to increase during early years, and stabilizes around the age of 10 years. Incidence is a mark of bipedism, and its role in sagittal balance is essential.
Variable angle transmittance of silver grid transparent electrodes
Zhao, Yuan-Yuan; Zheng, Mei-Ling; Dong, Xian-Zi; Zhao, Zhen-Sheng; Duan, Xuan-Ming
2016-10-01
We focus on investigating the optical transmittance of silver grid transparent electrodes (SGTEs) in variable angle view theoretically and experimentally, rather than the optical transmittance under the normal incidence. The variable angle transmittance (VAT) values of SGTEs are measured on a home-made experimental setup. The experimental results about difference of the transmittance difference under different angles are small and negligible, although the measured angle is changed. Theoretically, the physical mechanism on nearly constant transmittance for different angle view can be well explained according to the theory of geometrical optics. This study provides an approach for investigating the VAT values of SGTEs in a controllable fashion and the influence of viewing angle of the touch screen.
Luminosity Anti-leveling with Crossing Angle (MD 1669)
Gorzawski, Arkadiusz; Ponce, Laurette; Salvachua Ferrando, Belen Maria; Wenninger, Jorg; CERN. Geneva. ATS Department
2016-01-01
A significant fraction of the LHC luminosity ($\\sim$30\\% in 2016) is lost due to the presence (and necessity) of the crossing angles at the IPs. At the LHC the crossing angle is typically set to a value that provides sufficient separation of the beams at the start of fills for the peak bunch intensities. As the bunch intensity decays during a fill, it is possible to reduce the crossing angle and recover some luminosity. A smooth crossing angle reduction procedure must be developed to take advantage of this option during stable beam operation. During this MD a smooth procedure for luminosity leveling with crossing angle was tested. It was demonstrated that the orbit was well controlled, beam losses were low and the offset leveled experiments ALICE and LHCb were not affected by crossing angle leveling in ATLAS and CMS.
As-placed contact angles for sessile drops.
Tadmor, Rafael; Yadav, Preeti S
2008-01-01
As-placed contact angle is the contact angle a drop adapts as a result of its placement on a surface. As expected, the as-placed contact angle, thetaAP, of a sessile drop on a horizontal surface decreases with the drop size due to the increase in hydrostatic pressure. We present a theoretical prediction for thetaAP which shows that it is a unique function of the advancing contact angle, thetaA, drop size, and material properties (surface tensions and densities). We test our prediction with published and new data. The theory agrees with the experiments. From the relation of the as-placed contact angle to drop size the thermodynamic equilibrium contact angle is also calculated.
Mechanism and Etiology of Primary Chronic Angle Closure Glaucoma
无
1994-01-01
The ocular anatomic features, pupil-blocking force, status of angle synechiae closure and positivity of provocative tests were compared between the primary chronic angle closure glaucoma (PCACG) and primary a-cute angle closure glaucoma (PAACG) by using ultrasonic biometry, computerized anterior ocular segment image processing technique, gonioscopy and provocative tests. The studies showed that the anterior chamber depth of PAACG was shallower than that of PCACG; the pupil-blocking force of PAACG was st...
Bilateral acute angle-closure glaucoma after dexfenfluramine treatment.
Denis, P; Charpentier, D; Berros, P; Touameur, S
1995-01-01
We report the case of a patient with narrow angles who had an attack of bilateral acute angle-closure glaucoma precipitated by dexfenfluramine, a serotoninergic drug developed for appetite suppression. Although the exact mechanism remains uncertain, the pupillary block observed in our case may be the result of the serotoninergic or indirect parasympatholytic properties of the drug on the iris sphincter muscle. Serotonergic psychoactive drugs should be prescribed cautiously in patients with known narrow angles and should be monitored by an ophthalmologist.
Shape, gravity, and the perception of the right angle.
Maniatis, Lydia M
2010-01-01
Past efforts to determine whether orientation-dependent sensitivity to right angles is due to retinal or environmental/gravitational frames of reference have produced conflicting conclusions. I attempt to show that the chief factor underlying this phenomenon is, rather, the shape of the object containing the angle. This shape mediates the typical orientation of the object in a ground- gravity context and the consequent force-structure of the incorporated angle-a force structure that is reflected in the percept.
Analyzing the installation angle error of a SAW torque sensor
Fan, Yanping; Ji, Xiaojun; Cai, Ping
2014-09-01
When a torque is applied to a shaft, normal strain oriented at ±45° direction to the shaft axis is at its maximum, which requires two one-port SAW resonators to be bonded to the shaft at ±45° to the shaft axis. In order to make the SAW torque sensitivity high enough, the installation angle error of two SAW resonators must be confined within ±5° according to our design requirement. However, there are few studies devoted to the installation angle analysis of a SAW torque sensor presently and the angle error was usually obtained by a manual method. Hence, we propose an approximation method to analyze the angle error. First, according to the sensitive mechanism of the SAW device to torque, the SAW torque sensitivity is deduced based on the linear piezoelectric constitutive equation and the perturbation theory. Then, when a torque is applied to the tested shaft, the stress condition of two SAW resonators mounted with an angle deviating from ±45° to the shaft axis, is analyzed. The angle error is obtained by means of the torque sensitivities of two orthogonal SAW resonators. Finally, the torque measurement system is constructed and the loading and unloading experiments are performed twice. The torque sensitivities of two SAW resonators are obtained by applying average and least square method to the experimental results. Based on the derived angle error estimation function, the angle error is estimated about 3.447°, which is close to the actual angle error 2.915°. The difference between the estimated angle and the actual angle is discussed. The validity of the proposed angle error analysis method is testified to by the experimental results.
Rotating Shaft Tilt Angle Measurement Using an Inclinometer
2015-01-01
This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendic...
Investigation of drop dynamic contact angle on copper surface
Orlova Evgenija; Feoktistov Dmitriy; Kuznetsov Geniy
2015-01-01
This paper presents experimental results of the studying the effect of surface roughness, microstructure and flow rate on the dynamic contact angle at spreading of distilled non deaerate water drop on a solid horizontal substrates. Copper substrates with different roughness have been investigated. For each substrate static contact angles depending on volume flow rate have been obtained using shadow system. Increasing the volume flow rate resulted in an increase of the static contact angle. It...
UPPER LIMITS FOR THE CONTACT ANGLES OF LIQUIDS ON SOLIDS
available on equilibrium contact angles . These data were obtained under well- controlled and comparable experimental conditions for many liquids on...Earlier systematic studies of the angle of contact (theta) exhibited by drops of liquid on plane solid surfaces of low surface energy have made data...From the parameters defining this straight line, estimates can be made of the limiting contact angles for each liquid.
Dynamic contact angle at nano-scale: a unified view
Lukyanov, Alex V.; Likhtman, Alexei E.
2016-01-01
Generation of dynamic contact angle in the course of wetting is a fundamental phenomenon of nature. Dynamic wetting processes have a direct impact on flows at nano-scale, and therefore their understanding is exceptionally important to emerging technologies. Here, we reveal the microscopic mechanism of dynamic contact angle generation. It has been demonstrated using large-scale molecular dynamics simulations of bead-spring model fluids that the main cause of local contact angle variations is t...
Angle Class II correction with MARA appliance
Kelly Chiqueto
2013-02-01
Full Text Available OBJECTIVE: To assess the effects produced by the MARA appliance in the treatment of Angle's Class II, division 1 malocclusion. METHODS: The sample consisted of 44 young patients divided into two groups: The MARA Group, with initial mean age of 11.99 years, treated with the MARA appliance for an average period of 1.11 years, and the Control Group, with initial mean age of 11.63 years, monitored for a mean period of 1.18 years with no treatment. Lateral cephalograms were used to compare the groups using cephalometric variables in the initial and final phases. For these comparisons, Student's t test was employed. RESULTS: MARA appliance produced the following effects: Maxillary growth restriction, no change in mandibular development, improvement in maxillomandibular relationship, increased lower anterior facial height and counterclockwise rotation of the functional occlusal plane. In the upper arch, the incisors moved lingually and retruded, while the molars moved distally and tipped distally. In the lower arch, the incisors proclined and protruded, whereas the molars mesialized and tipped mesially. Finally, there was a significant reduction in overbite and overjet, with an obvious improvement in molar relationship. CONCLUSIONS: It was concluded that the MARA appliance proved effective in correcting Angle's Class II, division 1 malocclusion while inducing skeletal changes and particularly dental changes.OBJETIVO: avaliar os efeitos proporcionados pelo aparelho MARA no tratamento da má oclusão de Classe II, 1ª divisão. MÉTODOS: utilizou-se uma amostra de 44 jovens, divididos em dois grupos - Grupo MARA, com idade inicial média de 11,99 anos e tratado com o aparelho MARA por um período médio de 1,11 ano; e Grupo Controle, com idade inicial média de 11,63 ano e observado por um período médio de 1,18 ano, sem nenhum tratamento. Utilizou-se as telerradiografias em norma lateral para comparar os grupos quanto às variáveis cefalométricas das
周晓; 许亚军; 芮永军; 寿奎水; 陈学明
2013-01-01
Objective To investigate the effectiveness of repairing hallux metatarsophalangeal skin and soft tissue defect with medial flap with double blood supply system in elderly patients.Methods Between June 2011 and March 2012,9 cases (9 toes) of skin and soft tissue defect at hallux metatarsophalangeal joint were treated with medial flap with double blood supply system.There were 7 males and 2 females,aged 60-70 years (mean,65.4 years).Injury included crush injury in 5 cases,traffic accident injury in 4 cases.The interval of injury and operation ranged from 3 hours to 5 days (mean,35 hours).The patients had bone or tendon exposure with pollution of wounds.The size of defects ranged from 2.0 cm × 1.5 cm to 2.5 cm × 2.0 cm.The size of flaps ranged from 2.0 cm × 1.7 cm to 3.0 cm × 2.2 cm.Medial dorsal nerves were anastomosed with toe nerves to recover flap sensation.The donor site was repaired with skin grafting.Results All 9 flaps and skin grafting survived completely,and primary healing of wounds were obtained.Nine patients were followed up 6-8 months (mean,7 months).The colour,texture,and contour of the flaps were good.The two-point discrimination of the flaps was 12-16 mm (mean,14 mm) at last follow-up.The patients could walk normally.No scar contracture formed at donor site.No wear occurred.Conclusion The medial flap with double blood supply system can be used to repair hallux metatarsophalangeal skin and soft tissue defect in elderly patients because the flap can be easily obtained,has good blood supply,and has no injury to the main artery and nerve.%目的 探讨带两套血供的足内侧皮瓣修复老年患者(足母)趾跖趾关节附近皮肤软组织缺损的疗效.方法 2011年6月-2012年3月,收治9例(9趾)(足母)趾跖趾关节附近皮肤软组织缺损老年患者.男7例,女2例;年龄60～70岁,平均65.4岁.致伤原因:挤压伤5例,交通事故伤4例.伤后至手术时间为3h～5d,平均35h.创面污染,均伴骨或
Miloslav Klugar
2011-12-01
Full Text Available BACKGROUND: The hallux and the first metatarsophalangeal joint play a major role in load transmission during walking. OBJECTIVE: The main aim of this study was to investigate differences in kinematics of the pelvis and lower extremities during gait by comparing people with hallux valgus (HV and a control group (CG. METHODS: We compared subjects with asymptomatic bilateral HV (n = 6, 57.8 ± 5.64 years with those who had CG (n = 11, 50.7 ± 4.41 years. Gait analysis was investigated using an optoelectronic system Vicon MX. The subjects walked at self-selected speeds. In total, five trials of each subject were analyzed. The statistical processing was performed by means of the Student t-test. The effect size was determined using the ω2 measure. RESULTS: In people with HV there was a significantly smaller maximum of dorsal flexion during the stance phase (p 0.06 and a greater maximum of plantar flexion at the beginning of the stance phase (p 0.06. The maximum of knee extension at the end of the swing phase was significantly greater (p 0.06 in subjects with HV. In the frontal plane, a significantly smaller maximum of hip abduction (p 0.06 during the gait cycle was observed in people with HV. The range of the pelvic obliquity (p 0.06 and the pelvic rotation (p 0.06 were significantly smaller in people with HV. CONCLUSION: This study demonstrated that HV does not exclusively concern the foot. The valgus deformity of the big toe can negatively influence function of the lower extremities and can cause overloading of those segments as well.[VÝCHODISKA: Palec a I. metatarzofalangeální kloub hrají klíčovou úlohu v přenosu zatížení při chůzi. CÍLE: Účelem této studie bylo analyzovat a interpretovat rozdíly v kinematických parametrech chůze u osob s hallux valgus v porovnání s kontrolní skupinou. METODIKA: Porovnávali jsme osoby s asymptomatickou oboustrannou valgózní deformitou palce (n = 6; 57,8 ± 5,64 let s kontrolní skupinou
Chapman Solar Zenith Angle variations at Titan
Royer, Emilie M.; Ajello, Joseph; Holsclaw, Gregory; West, Robert; Esposito, Larry W.; Bradley, Eric Todd
2016-10-01
Solar XUV photons and magnetospheric particles are the two main sources contributing to the airglow in the Titan's upper atmosphere. We are focusing here on the solar XUV photons and how they influence the airglow intensity. The Cassini-UVIS observations analyzed in this study consist each in a partial scan of Titan, while the center of the detector stays approximately at the same location on Titan's disk. We used observations from 2008 to 2012, which allow for a wide range of Solar Zenith Angle (SZA). Spectra from 800 km to 1200 km of altitude have been corrected from the solar spectrum using TIMED/SEE data. We observe that the airglow intensity varies as a function of the SZA and follows a Chapman curve. Three SZA regions are identified: the sunlit region ranging from 0 to 50 degrees. In this region, the intensity of the airglow increases, while the SZA decreases. Between SZA 50 and 100 degrees, the airglow intensity decreases from it maximum to its minimum. In this transition region the upper atmosphere of Titan changes from being totally sunlit to being in the shadow of the moon. For SZA 100 to 180 degrees, we observe a constant airglow intensity close to zero. The behavior of the airglow is also similar to the behavior of the electron density as a function of the SZA as observed by Ågren at al (2009). Both variables exhibit a decrease intensity with increasing SZA. The goal of this study is to understand such correlation. We demonstrate the importance of the solar XUV photons contribution to the Titan airglow and prove that the strongest contribution to the Titan dayglow occurs by solar fluorescence rather than the particle impact that predominates at night.
Tachometer Derived From Brushless Shaft-Angle Resolver
Howard, David E.; Smith, Dennis A.
1995-01-01
Tachometer circuit operates in conjunction with brushless shaft-angle resolver. By performing sequence of straightforward mathematical operations on resolver signals and utilizing simple trigonometric identity, generates voltage proportional to rate of rotation of shaft. One advantage is use of brushless shaft-angle resolver as main source of rate signal: no brushes to wear out, no brush noise, and brushless resolvers have proven robustness. No switching of signals to generate noise. Another advantage, shaft-angle resolver used as shaft-angle sensor, tachometer input obtained without adding another sensor. Present circuit reduces overall size, weight, and cost of tachometer.
Contact-angle hysteresis on super-hydrophobic surfaces.
McHale, G; Shirtcliffe, N J; Newton, M I
2004-11-09
The relationship between perturbations to contact angles on a rough or textured surface and the super-hydrophobic enhancement of the equilibrium contact angle is discussed theoretically. Two models are considered. In the first (Wenzel) case, the super-hydrophobic surface has a very high contact angle and the droplet completely contacts the surface upon which it rests. In the second (Cassie-Baxter) case, the super-hydrophobic surface has a very high contact angle, but the droplet bridges across surface protrusions. The theoretical treatment emphasizes the concept of contact-angle amplification or attenuation and distinguishes between the increases in contact angles due to roughening or texturing surfaces and perturbations to the resulting contact angles. The theory is applied to predicting contact-angle hysteresis on rough surfaces from the hysteresis observable on smooth surfaces and is therefore relevant to predicting roll-off angles for droplets on tilted surfaces. The theory quantitatively predicts a "sticky" surface for Wenzel-type surfaces and a "slippy" surface for Cassie-Baxter-type surfaces.
Orientation angle workspaces of planar serial three-link manipulators
DAI; Jian; S
2009-01-01
This paper presents a classification on the workspaces of planar serial three-link manipulators, that is, position workspace and orientation angle workspace. Position workspace indicates the region reached by the reference point on the end-effector. Orientation angle workspace indicates a set of angle ranges by which the end-effector can reach with certain orientation for every point in the reachable position workspace. By introducing a virtual equivalent mechanism, reachable position workspace can be di- vided into several Grashof intervals and non-Grashof intervals. The calculation equations of orientation angle workspace are deduced in three situations according to the relationships among four link lengths in the virtual four-bar chain. Three examples are given for three kinds of relationship of link lengths. The orientation angle workspace of extended groups, that is, two of the three link lengths equal, and the orientation angle workspace when the reference point on the end-effector moves along a non-radial direction are also discussed. A program is developed to calculate orientation angle workspaces and output variation curves of orientation angle workspace and key data within the position workspace. The approach and program in this paper can be used for fast calculation and identification of the variation rule of the orientation angle workspace of any given planar serial three-link manipulator on the basis of its link parameters, and for the design of a highly dexterous serial manipulator with proposed link rela- tions.
Orientation angle workspaces of planar serial three-link manipulators
LI RuiQin; DAI Jian S
2009-01-01
This paper presents a classification on the workspaces of planar serial three-link manipulators, that is,position workspace and orientation angle workspace. Position workspace indicates the region reached by the reference point on the end-effector. Orientation angle workspace indicates a set of angle ranges by which the end-effector can reach with certain orientation for every point in the reachable position workspace. By introducing a virtual equivalent mechanism, reachable position workspace can be divided into several Grashof intervals and non-Grashof intervals. The calculation equations of orientation angle workspace are deduced in three situations according to the relationships among four link lengths in the virtual four-bar chain. Three examples are given for three kinds of relationship of link lengths.The orientation angle workspace of extended groups, that is, two of the three link lengths equal, end the orientation angle workspace when the reference point on the end-effector moves along a non-radial direction are also discussed. A program is developed to calculate orientation angle workspaces and output variation curves of orientation angle workspace and key data within the position workspace. The approach and program in this paper can be used for fast calculation and identification of the variation rule of the orientation angle workspace of any given planar serial three-link manipulator on the basis of its link parameters, and for the design of a highly dexterous serial manipulator with proposed link relations.
Tibial and fibular angles in homozygous sickle cell disease
Akamaguna, A.I.; Odita, J.C.; Ugbodaga, C.I.; Okafor, L.A.
1986-05-01
Measurements of the tibial and fibular angles made on ankle radiographs of 34 patients with sickle cell disease were compared with those of 36 normal Nigerians. Widening of the fibular angle, which is an indication of tibiotalar slant, was demonstrated in about 79% of sickle cell disease patients. By using fibular angle measurements as an objective method of assessing subtle tibiotalar slant, it is concluded that the incidence of this deformity is much higher among sickle cell disease patients than previously reported. The mean values of tibial and fibular angles in normal Nigerians are higher than has been reported amongst Caucasians.
Contact angle distribution of particles at fluid interfaces.
Snoeyink, Craig; Barman, Sourav; Christopher, Gordon F
2015-01-27
Recent measurements have implied a distribution of interfacially adsorbed particles' contact angles; however, it has been impossible to measure statistically significant numbers for these contact angles noninvasively in situ. Using a new microscopy method that allows nanometer-scale resolution of particle's 3D positions on an interface, we have measured the contact angles for thousands of latex particles at an oil/water interface. Furthermore, these measurements are dynamic, allowing the observation of the particle contact angle with high temporal resolution, resulting in hundreds of thousands of individual contact angle measurements. The contact angle has been found to fit a normal distribution with a standard deviation of 19.3°, which is much larger than previously recorded. Furthermore, the technique used allows the effect of measurement error, constrained interfacial diffusion, and particle property variation on the contact angle distribution to be individually evaluated. Because of the ability to measure the contact angle noninvasively, the results provide previously unobtainable, unique data on the dynamics and distribution of the adsorbed particles' contact angle.
Antibody elbow angles are influenced by their light chain class
Stanfield, R; Zemla, A; Wilson, I; Rupp, B
2006-01-12
We have examined the elbow angles for 365 different Fab fragments, and observe that Fabs with lambda light chains have adopted a wider range of elbow angles than their kappa-chain counterparts, and that the lambda light chain Fabs are frequently found with very large (>195{sup o}) elbow angles. This apparent hyperflexibility of lambda-chain Fabs may be due to an insertion in their switch region, which is one residue longer than in kappa chains, with glycine occurring most frequently at the insertion position. A new, web-based computer program that was used to calculate the Fab elbow angles is also described.
Influence of Atmospheric Refraction on Horizontal Angle Surveying
ZHANG Zhenglu; DENG Yong; LUO Changlin; MEI Wensheng
2006-01-01
Side-refraction is the main error source of horizontal angle surveying, but it has little influence on the sides by analyzing the influence of atmospheric-infraction on the ultrahigh-precision side and angle surveying. Choosing oriented direction is crucial to distance and angle measurement in triangulateration network. How to select the oriented direction during angle measurement is presented, and the means to check the quality of auto-surveying with Georobot is brought forward as well. At last some solutions to reduce the influence of side-refraction while disposing and surveying ultrahigh-precision triangulateration network are put forward.
Creation of a multi-reference-angle comparator
Bručas, Domantas; Giniotis, Vytautas
2009-03-01
Many geodetic and industrial instruments utilize precise angle determination. Metrological calibration and testing of such devices is very complicated, due to the large number of angular position values generated, and often cannot be accomplished using classical means of angle determination. Therefore a special comparator (test rig) capable of calibration geodetic and other angle-measuring instruments and implementing multiple references for angle determination has been created. Several modernized optical devices were used on the test rig, together with the implementation of a special calibration method. In this paper the construction of the rig, modernization of the optical devices, calibration, and some results of measurements are presented.
Revisiting the Force-Joint Angle Relationship After Eccentric Exercise.
Welsh, Molly C; Allen, David L; Batliner, Matthew E; Byrnes, William C
2015-12-01
The purpose of this study was to evaluate force-angle curve fitting techniques pre-eccentric exercise, quantify changes in curve characteristics postexercise, and examine the relationship between curve changes and markers of muscle damage. Fourteen males unaccustomed to eccentric exercise performed 60 eccentric muscle actions of the elbow flexors. Maximal voluntary isometric force was measured throughout a range of angles pre- (Pre1 and Pre2), immediately post (IP), and 1, 2, 4, and 7 days postexercise. Force-angle curves for each visit were constructed using second-order polynomials. Changes in curve characteristics (optimal angle, peak force, curve height), range of motion, soreness, and creatine kinase activity were quantified. Optimal joint angle and force at optimal angle were significantly correlated from Pre1 to Pre2 (ICC = 0.821 and 0.979, respectively). Optimal angle was significantly right shifted (p = 0.035) by 10.4 ± 12.9° from Pre2 to IP and was restored by 1 day post exercise. Interestingly, the r value for curve fit was significantly decreased (p exercise (r = 0.750). Curve height was significantly decreased (39%) IP and restored to pre-exercise height by 4 days postexercise. There was no correlation between optimal angle or curve height and other damage markers. In conclusion, force-angle relationships can be accurately described using second-order polynomials. After eccentric exercise, the force-angle curve is flattened and shifted (downward and rightward), but these changes are not correlated to other markers of muscle damage. Changes in the force-angle relationship are multifaceted, but determining the physiological significance of these changes requires further investigation.
Simulation of Canopy Leaf Inclination Angle in Rice
ZHANG Xiao-cui; LU Chuan-gen; HU Ning; YAO Ke-min; ZHANG Qi-jun; DAI Qi-gen
2013-01-01
A leaf inclination angle distribution model, which is applicable to simulate leaf inclination angle distribution in six heights of layered canopy at different growth stages, was established by component factors affecting plant type in rice. The accuracy of the simulation results was validated by measured values from a field experiment. The coefficient of determination (R2) and the root mean square error (RMSE) between the simulated and measured values were 0.9472 and 3.93%, respectively. The simulation results showed that the distribution of leaf inclination angles differed among the three plant types. The leaf inclination angles were larger in the compact variety Liangyoupeijiu with erect leaves than in the loose variety Shanyou 63 with droopy leaves and the intermediate variety Liangyou Y06. The leaf inclination angles were distributed in the lower range in Shanyou 63, which matched up with field measurements. The distribution of leaf inclination angles in the same variety changed throughout the seven growth stages. The leaf inclination angles enlarged gradually from transplanting to booting. During the post-booting period, the leaf inclination angle increased in Shanyou 63 and Liangyou Y06, but changed little in Liangyoupeijiu. At every growth stage of each variety, canopy leaf inclination angle distribution on the six heights of canopy layers was variable. As canopy height increased, the layered leaf area index (LAI) decreased in all the three plant types. However, while the leaf inclination angles showed little change in Liangyoupeijiu, they became larger in Shanyou 63 but smaller in Liangyou Y06. The simulation results used in the constructed model were very similar to the actual measurement values. The model provides a method for estimating canopy leaf inclination angle distribution in rice production.
Bioimpedance-Derived Phase Angle and Mortality Among Older People.
Genton, Laurence; Norman, Kristina; Spoerri, Adrian; Pichard, Claude; Karsegard, Véronique L; Herrmann, François R; Graf, Christophe E
2017-04-01
Phase angle measured by bioelectrical impedance analysis (BIA) may be a marker of health state. This historical cohort study of prospectively collected BIA measurements aims to investigate the link between phase angle and mortality in older people and evaluate whether a phase angle cutoff can be defined. We included all adults aged ≥65 years who underwent a BIA measurement by the Nutriguard(®) device at the Geneva University Hospitals. We retrieved retrospectively the phase angle and comorbidities at the last BIA measurement and mortality until December 2012. We calculated phase angle standardized for sex, age, and body mass index (BMI), using reference values determined with the same brand of BIA device. Sex-specific and standardized phase angle were categorized into quartiles. The association of mortality with sex-specific or standardized phase angle was evaluated through univariate and multivariate Cox regression models, Kaplan-Meier curves, and receiver operating characteristic (ROC) curves. We included 1307 (38% women) participants, among whom 628 (44% women) died. In a multivariate Cox regression model adjusted for comorbidities and setting of measurement (ambulatory vs. hospitalized), the protective effect against mortality increased progressively as the standardized phase angle quartile increased (HR 0.71 [95% CI 0.58, 0.86], 0.53 [95% CI 0.42, 0.67], and 0.32 [95% CI 0.23, 0.43]). The discriminative value of continuous standardized phase angle, assessed as the area under the ROC curve, was 0.72 (95%CI 0.70, 0.75). We could not define an acceptable phase angle cutoff for individual prediction of mortality (LK), based on sensibility and specificity values. This study shows the association of phase angle and mortality in older patients, independent of age, sex, comorbidities, BMI categories, and setting of measurement.
Role of Optical Coherence Tomography in Assessing Anterior Chamber Angles
Kochupurakal, Reema Thomas; Jha, Kirti Nath; Rajalakshmi, A.R.; Nagarajan, Swathi; Ezhumalai, G.
2016-01-01
Introduction Gonioscopy is the gold standard in assessing anterior chamber angles. However, interobserver variations are common and there is a need for reliable objective method of assessment. Aim To compare the anterior chamber angle by gonioscopy and Spectral Domain Optical Coherence Tomography (SD-OCT) in individuals with shallow anterior chamber. Materials and Methods This comparative observational study was conducted in a rural tertiary multi-speciality teaching hospital. A total of 101 eyes of 54 patients with shallow anterior chamber on slit lamp evaluation were included. Anterior chamber angle was graded by gonioscopy using the shaffer grading system. Angles were also assessed by SD-OCT with Trabecular Iris Angle (TIA) and Angle Opening Distance (AOD). Chi-square test, sensitivity, specificity, positive and negative predictive value to find correlation between OCT parameters and gonioscopy grading. Results Females represented 72.7%. The mean age was 53.93 ±8.24 years and mean anterior chamber depth was 2.47 ± 0.152 mm. Shaffer grade ≤ 2 were identified in 95(94%) superior, 42(41.5%) inferior, 65(64.3%) nasal and 57(56.4%) temporal quadrants. Cut-off values of TIA ≤ 22° and AOD ≤ 290 μm were taken as narrow angles on SD-OCT. TIA of ≤ 22° were found in 88(92.6%) nasal and 87(87%) temporal angles. AOD of ≤ 290 μm was found in 73(76.8%) nasal and 83(83%) temporal quadrants. Sensitivity in detecting narrow angles was 90.7% and 82.2% for TIA and AOD, while specificity was 11.7% and 23.4%, respectively. Conclusion Individuals were found to have narrow angles more with SD-OCT. Sensitivity was high and specificity was low in detecting narrow angles compared to gonioscopy, making it an unreliable tool for screening. PMID:27190851
Investigation of Complex Angle Processing to Reduce Radome Induced Angle Pointing Errors.
1979-10-01
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Stocco, Antonio; Su, Ge; Nobili, Maurizio; In, Martin; Wang, Dayang
2014-09-28
Here multiple angle of incidence ellipsometry was successfully applied to in situ assess the contact angle and surface coverage of gold nanoparticles as small as 18 nm, coated with stimuli-responsive polymers, at water-oil and water-air interfaces in the presence of NaCl and NaOH, respectively. The interfacial adsorption of the nanoparticles was found to be very slow and took days to reach a fairly low surface coverage. For water-oil interfaces, in situ nanoparticle contact angles agree with the macroscopic equilibrium contact angles of planar gold surfaces with the same polymer coatings, whilst for water-air interfaces, significant differences have been observed.
Accelerated iterative beam angle selection in IMRT
Bangert, Mark, E-mail: m.bangert@dkfz.de [Department of Medical Physics in Radiation Oncology, German Cancer Research Center—DKFZ, Im Neuenheimer Feld 280, Heidelberg D-69120 (Germany); Unkelbach, Jan [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)
2016-03-15
Purpose: Iterative methods for beam angle selection (BAS) for intensity-modulated radiation therapy (IMRT) planning sequentially construct a beneficial ensemble of beam directions. In a naïve implementation, the nth beam is selected by adding beam orientations one-by-one from a discrete set of candidates to an existing ensemble of (n − 1) beams. The best beam orientation is identified in a time consuming process by solving the fluence map optimization (FMO) problem for every candidate beam and selecting the beam that yields the largest improvement to the objective function value. This paper evaluates two alternative methods to accelerate iterative BAS based on surrogates for the FMO objective function value. Methods: We suggest to select candidate beams not based on the FMO objective function value after convergence but (1) based on the objective function value after five FMO iterations of a gradient based algorithm and (2) based on a projected gradient of the FMO problem in the first iteration. The performance of the objective function surrogates is evaluated based on the resulting objective function values and dose statistics in a treatment planning study comprising three intracranial, three pancreas, and three prostate cases. Furthermore, iterative BAS is evaluated for an application in which a small number of noncoplanar beams complement a set of coplanar beam orientations. This scenario is of practical interest as noncoplanar setups may require additional attention of the treatment personnel for every couch rotation. Results: Iterative BAS relying on objective function surrogates yields similar results compared to naïve BAS with regard to the objective function values and dose statistics. At the same time, early stopping of the FMO and using the projected gradient during the first iteration enable reductions in computation time by approximately one to two orders of magnitude. With regard to the clinical delivery of noncoplanar IMRT treatments, we could
Virtuts castrenses de l'angle recte
Antonio Bustamante
2003-01-01
Full Text Available Está muy arraigada la idea de que, en una postura sedente sana, los segmentos corporales han de orientarse en ángulo recto. La desinformación que encierra esta idea es demasiado evidente y puede parecer fácil, a primera vista, retirar de la circulación esta paradójica receta; pero no es así. La pertinaz veneración de lo ortogonal que, en lo postural, se encuentra por doquier, ha hecho sospechar al autor que la fuerza de los 90° no se debe a errores de apreciación biomecánica, sino a simbologías cuyo origen, si no se pierde en la noche de los tiempos, sí que aparece en la aurora del Neolítico. Este artículo trata de mostrar que si lo ortogonal está justificado por la cultura para la construcción de objetos, no lo está para la adopción de posturas sedentes. _____________________________________________________________________________________________________________________________________________________________________ L’idée est profondément ancrée dans les esprits que dans une position assise correcte les segments corporaux doivent former entre eux une série d’angles droits. L’ignorance qui se cache derrière cette conception semble à priori trop évidente et devrait être facile à combattre, or tel n’est pas le cas. La vénération persistante de la position orthogonale est si étendue qu’elle a amené l’auteur à soupçonner que le culte des 90 degrés n’est pas dû à des erreurs d’appréciation biomécaniques mais à une forte symbologie dont les origines si elles ne remontent pas à la nuit des temps, renvoient au moins à l’aube du Néolithique. L’article essaie de démontrer que si la position orthogonale est culturellement justifiée pour la fabrication d’objets elle ne l’est pas de façon systématique pour ce qui de s’asseoir.The idea is well-rooted that in a healthy sitting position the segments of the body have to adopt a right angle. The disinformation surrounding this idea is
Showers with large zenith angles observed in emulsion chambers
任敬儒; 陆穗苓; 解卫; 王承瑞; 何瑁; 张乃健
1997-01-01
Showers with large zenith angles are observed in emulsion chambers exposed at Mt.Kanbala.The intensity of high energy muons is given and the multicore showers with large zenith angles are found.It is indicated that a new phenomenon may exist in the high energy nuclear interactions of cosmic rays.
Properties of tangential and radial angles of muons in EAS
Zabierowski, J.; Daumiller, K.; Doll, P.
2002-01-01
Tangential and radial angles of muons in EAS, a useful concept in investigation of the muon production height, can be used also for the investigation of the muon momenta. A parameter zeta, being a combination of tangential and radial angles, is introduced and its possible applications in investigation of muons in showers are presented.
Angle dependence of Andreev scattering at semiconductor-superconductor interfaces
Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka
1999-01-01
and increase of the probability of normal reflection. We show that in the presence of a Fermi velocity mismatch between the semiconductor and the superconductor the angles of incidence and transmission are related according to the well-known Snell's law in optics. As a consequence there is a critical angle...
V-shaped nematogens with the "magic bent angle".
Seltmann, Jens; Müller, Kathrin; Klein, Susanne; Lehmann, Matthias
2011-06-21
V-shaped nematogens 1a-c and 2a-b with benzodithiophene bending units have been synthesised. The derivatives 1a-c comprise a flat core with a bending angle of 109°, which is almost the tetrahedral angle proposed to be optimal in the realization of mesogens forming a biaxial nematic thermotropic mesophase.
Hierarchically structured superoleophobic surfaces with ultralow contact angle hysteresis.
Kota, Arun K; Li, Yongxin; Mabry, Joseph M; Tuteja, Anish
2012-11-14
Hierarchically structured, superoleophobic surfaces are demonstrated that display one of the lowest contact angle hysteresis values ever reported - even with extremely low-surface-tension liquids such as n-heptane. Consequently, these surfaces allow, for the first time, even ≈2 μL n-heptane droplets to bounce and roll-off at tilt angles. ≤ 2°.
Contact angle hysteresis: a review of fundamentals and applications
Eral, H.B.; Mannetje, 't D.J.C.M.; Oh, J.M.
2013-01-01
Contact angle hysteresis is an important physical phenomenon. It is omnipresent in nature and also plays a crucial role in various industrial processes. Despite its relevance, there is a lack of consensus on how to incorporate a description of contact angle hysteresis into physical models. To clarif
The Extent of Visual Space Inferred from Perspective Angles
Casper J. Erkelens
2015-02-01
Full Text Available Retinal images are perspective projections of the visual environment. Perspective projections do not explain why we perceive perspective in 3-D space. Analysis of underlying spatial transformations shows that visual space is a perspective transformation of physical space if parallel lines in physical space vanish at finite distance in visual space. Perspective angles, i.e., the angle perceived between parallel lines in physical space, were estimated for rails of a straight railway track. Perspective angles were also estimated from pictures taken from the same point of view. Perspective angles between rails ranged from 27% to 83% of their angular size in the retinal image. Perspective angles prescribe the distance of vanishing points of visual space. All computed distances were shorter than 6 m. The shallow depth of a hypothetical space inferred from perspective angles does not match the depth of visual space, as it is perceived. Incongruity between the perceived shape of a railway line on the one hand and the experienced ratio between width and length of the line on the other hand is huge, but apparently so unobtrusive that it has remained unnoticed. The incompatibility between perspective angles and perceived distances casts doubt on evidence for a curved visual space that has been presented in the literature and was obtained from combining judgments of distances and angles with physical positions.
Engineering sidewall angles of silica-on-silicon waveguides
Haiyan, Ou
2004-01-01
Burned photoresist is used as etch mask when producing silica-onsilicon waveguides. The sidewall angle of the optical glass waveguides is engineered by varying photoresist thickness and etch selectivity. The principle for the formation of the angles is introduced and very promising experimental...
Tube thoracostomy: Increased angle of insertion is associated with complications.
Hernandez, Matthew C; Laan, Danuel V; Zimmerman, Stacey L; Naik, Nimesh D; Schiller, Henry J; Aho, Johnathon M
2016-08-01
Tube thoracostomy (TT), considered a routine procedure, has significant complications. Current recommendations for placement rely on surface anatomy. There is no information to guide operators regarding angle of insertion relative to chest wall. We aim to determine if angle of insertion is associated with complications of TT. We performed a retrospective review of adult trauma patients who necessitated TT at a Level I trauma center over a 2-year period (January 2012 to December 2013). Tube thoracostomies performed intraoperatively or using radiological guidance were excluded. Thoracic anteroposterior or posteroanterior radiographs were reviewed to determine the angle of insertion of TT relative to the thoracic wall. A previously validated classification method was used to categorize complications. Descriptive and univariate statistics were used to compare angle of insertion and complicated versus uncomplicated TT. Review identified 154 patients who underwent a total of 246 TT placed for emergent trauma. All patients had a postprocedural chest x-ray. We identified 90 complications (37%) over the study period. One hundred forty-four of the TTs reviewed had an angle of insertion less than 45 degrees of which there were 27 complications (19%). One hundred two of the TTs had an angle greater than 45 degrees and 63 complications (62%); p thoracostomy insertion is inherently dangerous. Placement of TT using a higher angle of insertion greater than 45 degrees is associated with increased complications. Further prospective studies quantifying TT angle of insertion on outcomes are needed. Therapeutic study, level IV.
An assessment of recreational bank angling in the Free State ...
1Free State Department of Economic, Small Business Development, Tourism and Environmental Affairs, .... the seasonal flows of the rivers and reported that the best angling was to be ... of the event. The aim ... (ground bait) and angling places may not be marked. ..... working on the eutrophic Hartbeespoort Dam, estimated.
The effective take-off angle in PHI Quantera systems
Van der Marel, C.
2010-01-01
It is well known that for quantitative analysis of XPS results theeffective take-off angle of the electrons is an important parameter.In the report is shown that the effective take-off angle i n PHI Quantera systems deviates significanlty from the set value. This is NOT a consequence of inadequa
EVALUATION OF NECK SHAFT ANGLE OF FEMUR ON DRY BONES
Radha
2015-04-01
Full Text Available BACKGROUND: Evaluation of the neck shaft angle of femur helps to understand clinical relevance in bio mechanics of the hip joint. It helps for the better treatment of different pathological conditions of hip and femur and also to design prosthesis. Femoral neck shaft angle is important to convey the information regarding the race to which they belong. Hence the present study was under taken to determine the neck shaft angle of femur in humans. OBJECTIVE: 1. To correct the different types of deformity and to have a normal good walking Mechanism. 2. To know the recent methodology and attempt to evaluate the range of normal Angles of femora and their sex differences. METHODS: ANTHROPOMETRIC: 100 Adult dry bones were studied and analyzed . The neck shaft angle of femur was measured by tracing outlines of contours of all femora. RESULTS: The neck shaft angle of the femur have revealed that there is no much difference in between males and females. There was slightly higher 0.2° in females. INTERPRETATION & CONCLUSION: There was no significant gender difference in neck shaft angle. The Knowledge of knowing the neck shaft angle helps to understand the Biomechanics of the hip joint and also for better treatment of pathological condition of hip and femur.
EVALUATION OF NECK SHAFT ANGLE OF FEMUR ON DRY BONES
Radha; Ravi Shankar; Naveen; Roopa
2015-01-01
BACKGROUND: Evaluation of the neck shaft angle of femur helps to understand clinical relevance in bio mechanics of the hip joint. It helps for the better treatment of different pathological conditions of hip and femur and also to design prosthesis. Femoral neck shaft angle is important to convey the information regarding the race to ...
Dynamic aspects of contact angle measurements on adsorbed protein layers
Scheer, van der At; Smolders, Cees A.
1978-01-01
Contact angle measurements using drops of paraffin oil have been performed on polystyrene (PS) substrates, coated with human serum albumin (HSA) or human fibrinogen (HFb), immersed in buffer solution. The contact angle appeared to be time dependent. The final value for HSA-coated substrates was 50°
Bite angle effects of diphosphines in carbonylation reactions
P.W.N.M. van Leeuwen; Z. Freixa
2008-01-01
This chapter contains sections titled: * Introduction * Rhodium-Catalyzed Hydroformylation o Introduction o Steric Bite Angle Effect and Regioselectivity o Electronic Bite Angle Effect and Activity o Isotope Effects [24] * Platinum-Catalyzed Alkene Hydroformylation * Palladium-Catalyzed CO/Ethene Co
Investigation of Polarimetric SAR Data Acquired at Multiple Incidence Angles
Svendsen, Morten Thougaard; Skriver, Henning; Thomsen, A.
1998-01-01
The dependence of different polarimetric parameters on the incidence angles in the range of 30° to 60° is investigated for a number of different crops using airborne SAR data. The purpose of the investigation is to determine the effect of the variation of incidence angle within a SAR image when...
A Novel Monopulse Angle Estimation Method for Wideband LFM Radars
Yi-Xiong Zhang
2016-06-01
Full Text Available Traditional monopulse angle estimations are mainly based on phase comparison and amplitude comparison methods, which are commonly adopted in narrowband radars. In modern radar systems, wideband radars are becoming more and more important, while the angle estimation for wideband signals is little studied in previous works. As noise in wideband radars has larger bandwidth than narrowband radars, the challenge lies in the accumulation of energy from the high resolution range profile (HRRP of monopulse. In wideband radars, linear frequency modulated (LFM signals are frequently utilized. In this paper, we investigate the monopulse angle estimation problem for wideband LFM signals. To accumulate the energy of the received echo signals from different scatterers of a target, we propose utilizing a cross-correlation operation, which can achieve a good performance in low signal-to-noise ratio (SNR conditions. In the proposed algorithm, the problem of angle estimation is converted to estimating the frequency of the cross-correlation function (CCF. Experimental results demonstrate the similar performance of the proposed algorithm compared with the traditional amplitude comparison method. It means that the proposed method for angle estimation can be adopted. When adopting the proposed method, future radars may only need wideband signals for both tracking and imaging, which can greatly increase the data rate and strengthen the capability of anti-jamming. More importantly, the estimated angle will not become ambiguous under an arbitrary angle, which can significantly extend the estimated angle range in wideband radars.
46 CFR 58.01-40 - Machinery, angles of inclination.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Machinery, angles of inclination. 58.01-40 Section 58.01... AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-40 Machinery, angles of inclination. (a) Propulsion machinery and all auxiliary machinery essential to the propulsion and safety of the vessel must...
Poincare duality angles for Riemannian manifolds with boundary
Shonkwiler, Clayton
2009-01-01
On a compact Riemannian manifold with boundary, the absolute and relative cohomology groups appear as certain subspaces of harmonic forms. DeTurck and Gluck showed that these concrete realizations of the cohomology groups decompose into orthogonal subspaces corresponding to cohomology coming from the interior and boundary of the manifold. The principal angles between these interior subspaces are all acute and are called Poincare duality angles. This paper determines the Poincare duality angles of a collection of interesting manifolds with boundary derived from complex projective spaces and from Grassmannians, providing evidence that the Poincare duality angles measure, in some sense, how "close" a manifold is to being closed. This paper also elucidates a connection between the Poincare duality angles and the Dirichlet-to-Neumann operator for differential forms, which generalizes the classical Dirichlet-to-Neumann map arising in the problem of Electrical Impedance Tomography. Specifically, the Poincare duality...
Optimal handle angle of the fencing foil for improved performance.
Lin, Fang-Tsan
2004-06-01
Improperly designed hand tools and sports equipment contribute to undesired injuries and accidents. The idea of bending the tool, not the wrist, has been applied to sports equipment. According to Bennett's idea, the design of an ideal handle angle should be in the range of 14 degrees to 24 degrees. Thus design of the handle angle in the sport of fencing is also important. A well-designed handle angle could not only reduce ulnar deviation to avoid wrist injury but also enhance performance. An experiment with several different handle angles was conducted to analyze the effect on performance. Analysis showed an angle of 18 degrees to 21 degrees provided best overall performance in fencing.
Contact angles in the pseudopotential lattice Boltzmann modeling of wetting
Li, Q; Kang, Q J; Chen, Q
2014-01-01
In this paper, we aim to investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio. The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994)] is a popular mesoscopic model for simulating multiphase flows and interfacial dynamics. In this model, the contact angle is usually realized by a fluid-solid interaction. Two widely used fluid-solid interactions: the density-based interaction and the pseudopotential-based interaction, as well as a modified pseudopotential-based interaction formulated in the present paper, are numerically investigated and compared in terms of the achievable contact angles, the maximum and the minimum densities, and the spurious currents. It is found that the pseudopotential-based interaction works well for simulating small static (liquid) contact angles, however, is unable to reproduce static contact angles close to 180 degrees. Meanwhile, it is found that the proposed modif...
The effect of knee joint angle on torque control.
Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T
2010-01-01
The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque.
Deep learning methods for protein torsion angle prediction.
Li, Haiou; Hou, Jie; Adhikari, Badri; Lyu, Qiang; Cheng, Jianlin
2017-09-18
Deep learning is one of the most powerful machine learning methods that has achieved the state-of-the-art performance in many domains. Since deep learning was introduced to the field of bioinformatics in 2012, it has achieved success in a number of areas such as protein residue-residue contact prediction, secondary structure prediction, and fold recognition. In this work, we developed deep learning methods to improve the prediction of torsion (dihedral) angles of proteins. We design four different deep learning architectures to predict protein torsion angles. The architectures including deep neural network (DNN) and deep restricted Boltzmann machine (DRBN), deep recurrent neural network (DRNN) and deep recurrent restricted Boltzmann machine (DReRBM) since the protein torsion angle prediction is a sequence related problem. In addition to existing protein features, two new features (predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments) are used as input to each of the four deep learning architectures to predict phi and psi angles of protein backbone. The mean absolute error (MAE) of phi and psi angles predicted by DRNN, DReRBM, DRBM and DNN is about 20-21° and 29-30° on an independent dataset. The MAE of phi angle is comparable to the existing methods, but the MAE of psi angle is 29°, 2° lower than the existing methods. On the latest CASP12 targets, our methods also achieved the performance better than or comparable to a state-of-the art method. Our experiment demonstrates that deep learning is a valuable method for predicting protein torsion angles. The deep recurrent network architecture performs slightly better than deep feed-forward architecture, and the predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments are useful features for improving prediction accuracy.
Micheal, S.; Ayub, H.; Khan, M.I.; Bakker, B.; Schoenmaker-Koller, F.E.; Ali, M.; Akhtar, F.; Khan, W.A.; Qamar, R.; Hollander, A.I. den
2014-01-01
PURPOSE: Despite the different etiology of primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG), and pseudoexfoliative glaucoma (PEXG), several studies have suggested that these forms of glaucoma have overlapping genetic risk factors. Therefore, the aim of this study was to eval
EFFECT OF SWEEP ANGLE ON THE VORTICAL FLOW OVER DELTA WINGS AT AN ANGLE OF ATTACK OF 10°
JAMES BRETT
2014-12-01
Full Text Available CFD simulations have been used to analyse the vortical flows over sharp edged delta wings with differing sweep angles under subsonic conditions at an angle of attack of 10°. RANS simulations were validated against experimental data for a 65° sweep wing, with a flat cross-section, and the steadiness of the flow field was assessed by comparing the results against unsteady URANS and DES simulations. To assess the effect of sweep angle on the flow field, a range of sweep angles from 65° to 43° were simulated. For moderate sweep wings the primary vortex was observed to detach from the leading edge, undergoing vortex breakdown, and a weaker, replacement, "shadow" vortex was formed. The shadow vortex was observed for sweep angles of 50° and less, and resulted in reduced lift production near the wing tips loss of the stronger primary vortex.
Good, Philipp; Cooper, Thomas; Querci, Marco; Wiik, Nicolay; Ambrosetti, Gianluca; Steinfeld, Aldo
2016-03-01
The spectral specular reflectance of conventional and novel reflective materials for solar concentrators is measured with an acceptance angle of 17.5 mrad over the wavelength range 300-2500 nm at incidence angles 15-60° using a spectroscopic goniometry system. The same experimental setup is used to determine the spectral narrow-angle transmittance of semi-transparent materials for solar collector covers at incidence angles 0-60°. In addition, the angle-resolved surface scattering of reflective materials is recorded by an area-scan CCD detector over the spectral range 350-1050 nm. A comprehensive summary, discussion, and interpretation of the results are included in the associated research article "Spectral reflectance, transmittance, and angular scattering of materials for solar concentrators" in Solar Energy Materials and Solar Cells.
Philipp Good
2016-03-01
Full Text Available The spectral specular reflectance of conventional and novel reflective materials for solar concentrators is measured with an acceptance angle of 17.5 mrad over the wavelength range 300−2500 nm at incidence angles 15–60° using a spectroscopic goniometry system. The same experimental setup is used to determine the spectral narrow-angle transmittance of semi-transparent materials for solar collector covers at incidence angles 0–60°. In addition, the angle-resolved surface scattering of reflective materials is recorded by an area-scan CCD detector over the spectral range 350–1050 nm. A comprehensive summary, discussion, and interpretation of the results are included in the associated research article “Spectral reflectance, transmittance, and angular scattering of materials for solar concentrators” in Solar Energy Materials and Solar Cells.
Dynamic angle selection in X-ray computed tomography
Dabravolski, Andrei, E-mail: andrei.dabravolski@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Batenburg, Kees Joost, E-mail: joost.batenburg@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Centrum Wiskunde and Informatica (CWI), Science Park 123, 1098 XG Amsterdam (Netherlands); Sijbers, Jan, E-mail: jan.sijbers@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium)
2014-04-01
Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes.
A study of images of Projective Angles of pulmonary veins
Wang Jue [Beijing Anzhen Hospital, Beijing (China); Zhaoqi, Zhang [Beijing Anzhen Hospital, Beijing (China)], E-mail: zhaoqi5000@vip.sohu.com; Yu Wei; Miao Cuilian; Yan Zixu; Zhao Yike [Beijing Anzhen Hospital, Beijing (China)
2009-09-15
Aims: In images of magnetic resonance and computed tomography (CT) there are visible angles between pulmonary veins and the coronary, transversal or sagittal section of body. In this study these angles are measured and defined as Projective Angles of pulmonary veins. Several possible influential factors and characters of distribution are studied and analyzed for a better understanding of this imaging anatomic character of pulmonary veins. And it could be the anatomic base of adjusting correctly the angle of the central X-ray of the angiography of pulmonary veins undergoing the catheter ablation of atrial fibrillation (AF). Method: Images of contrast enhanced magnetic resonance angiography (CEMRA) and contrast enhanced computer tomography (CECT) of the left atrium and pulmonary veins of 137 health objects and patients with atrial fibrillation (AF) are processed with the technique of post-processing, and Projective Angles to the coronary and transversal sections are measured and analyzed statistically. Result: Project Angles of pulmonary veins are one of real and steady imaging anatomic characteristics of pulmonary veins. The statistical distribution of variables is relatively concentrated, with a fairly good representation of average value. It is possible to improve the angle of the central X-ray according to the average value in the selective angiography of pulmonary veins undergoing the catheter ablation of AF.
RESEARCH OF BASIFACIAL CONTOURING SCULPTURE BY MANDIBULAR ANGLE OSTECTOMY
FANG Jian-lin; DAI Chuan-chang; ZHU Guo-xian; ZHANG Ying; JIN Yu-qing; WANG Wei; QI Chuan-liang
2006-01-01
Objective Mandibular angle ostectomy is usually applied to the facial contouring sculpture.We evaluated the various techniques in order to enhance the precision and avoid unnecessary damage. Methods Before operation the area and quantity resected bone were designed according to facial measurement, mandible pantomography and orthophoria and lateral localized radiograph of skull. The Incises of mandibular angle ostectomy included intraoral, retroauricular or intraoral associated with retroauricular. Howerer, the sagittal resection of mandible outer table was necessary in all intraoral incise. Results Single mandibular angle ostectomy was not satisfactory for the patients having mandible hypertrophy with over-width basifacial contouring. Mandibular angle ostectomy combined with the sagittal resection of outer table of mandibular angle were required. Good symmetry and ap pearance were gained in 206 cases. One case had facial paralysis. Two patients occured mandibular fracture during the operation. Three cases complicated angled deformity at mandible body. Conclusion Reduction mandibuloplasty should be selected depends on varied types of mandibular angle hypertrophy before operation.
Geometric relation for neutrino mixing angles and theta(13)
Lipmanov, E M
2011-01-01
Inspired by the recent T2K discovery of a relatively large theta(13) angle in the neutrino mixing matrix we propose here a simple geometric relation between the three usually thought "independent" neutrino mixing angles - solar {\\theta}12, atmospheric {\\theta}23 and reactor {\\theta}13 ones: cos2(2{\\theta}sol) + cos2(2{\\theta}atm) + cos2(2{\\theta}13) = 1. Using the estimations for the two largest neutrino mixing angles from experimental data analyses in the literature, {\\theta}sol{\\cong} ~ 34.4o, {\\theta}atm{\\cong} ~ 42.8o, the reactor neutrino mixing angle is uniquely predicted {\\theta}13 = 10.8o. In case a little changed data, {\\theta}sol{\\cong} = 34o and {\\theta}atm{\\cong} = 43o the result will be {\\theta}13 =11.2o. And so, the {\\theta}13-value is not very sensitive to the accurate magnitudes of the two largest mixing angles. That prediction for the 'small' neutrino mixing angle is compatible with the latest T2K experimental data with best fit values for the reactor angle ({\\theta}13)bf{\\cong}= 9.7o(11o) fo...
Going round the bend: Persistent personal biases in walked angles.
Jetzschke, Simon; Ernst, Marc O; Moscatelli, Alessandro; Boeddeker, Norbert
2016-03-23
For navigation through our environment, we can rely on information from various modalities, such as vision and audition. This information enables us for example to estimate our position relative to the starting position, or to integrate velocity and acceleration signals from the vestibular organ and proprioception to estimate the displacement due to self-motion. To better understand the mechanisms that underlie human navigation we analysed the performance of participants in an angle-walking task in the absence of visual and auditory signals. To this end, we guided them along paths of different lengths and asked them to turn by an angle of ±90°. We found significant biases in turn angles, i.e. systematic deviations from the correct angle and that these were characteristic for individual participants. Varying path length, however, had little effect on turn accuracy and precision. To check whether this idiosyncrasy was persistent over time and present in another type of walking task, we performed a second experiment several weeks later. Here, the same participants were guided to walk angles with varying amplitude. We then asked them to judge whether they had walked an angle larger or smaller than 90° in a two-alternative forced-choice paradigm. The personal bias was highly correlated between the two experiments even though they were conducted weeks apart. The presence of a persistent bias in walked angles in the absence of external directional cues indicates a possible error component for navigation, which is surprisingly time stable and idiosyncratic.
Biophysical optimality of the golden angle in phyllotaxis.
Okabe, Takuya
2015-10-16
Plant leaves are arranged around a stem axis in a regular pattern characterized by common fractions, a phenomenon known as phyllotaxis or phyllotaxy. As plants grow, these fractions often transition according to simple rules related to Fibonacci sequences. This mathematical regularity originates from leaf primordia at the shoot tip (shoot apical meristem), which successively arise at fixed intervals of a divergence angle, typically the golden angle of 137.5°. Algebraic and numerical interpretations have been proposed to explain the golden angle observed in phyllotaxis. However, it remains unknown whether phyllotaxis has adaptive value, even though two centuries have passed since the phenomenon was discovered. Here, I propose a new adaptive mechanism explaining the presence of the golden angle. This angle is the optimal solution to minimize the energy cost of phyllotaxis transition. This model accounts for not only the high precision of the golden angle but also the occurrences of other angles observed in nature. The model also effectively explains the observed diversity of rational and irrational numbers in phyllotaxis.
Performance analysis of CO2 laser polished angled ribbon fiber
Sohn, Ik-Bu; Choi, Hun-Kook; Noh, Young-Chul; Lee, Man-Seop; Oh, Jin-Kyoung; Kim, Seong-min; Ahsan, Md. Shamim
2017-01-01
This paper demonstrates CO2 laser assisted simultaneous polishing of angled ribbon fibers consisting eight set of optical fibers. The ribbon fibers were rotated vertically at an angle of 12° and polished by repetitive irradiation of CO2 laser beam at the end faces of the fibers. Compared to mechanically polished sharp edged angled fibers, CO2 laser polishing forms curve edged angled fibers. Increase in the curvature of the end faces of the ribbon fibers causes the increase of the fibers' strength, which in turn represents great robustness against fiber connections with other devices. The CO2 laser polished angled fibers have great smoothness throughout the polished area. The smoothness of the fiber end faces have been controlled by varying the number of laser irradiation. After CO2 laser polishing, the average value of the fiber angle of the ribbon fibers is ∼8.28°. The laser polished ribbon fibers show low insertion and return losses when connecting with commercial optical communication devices. The proposed technique of polishing the angled ribbon fibers is highly replicable and reliable and thus suitable for commercial applications.
Biophysical optimality of the golden angle in phyllotaxis
Okabe, Takuya
2015-10-01
Plant leaves are arranged around a stem axis in a regular pattern characterized by common fractions, a phenomenon known as phyllotaxis or phyllotaxy. As plants grow, these fractions often transition according to simple rules related to Fibonacci sequences. This mathematical regularity originates from leaf primordia at the shoot tip (shoot apical meristem), which successively arise at fixed intervals of a divergence angle, typically the golden angle of 137.5°. Algebraic and numerical interpretations have been proposed to explain the golden angle observed in phyllotaxis. However, it remains unknown whether phyllotaxis has adaptive value, even though two centuries have passed since the phenomenon was discovered. Here, I propose a new adaptive mechanism explaining the presence of the golden angle. This angle is the optimal solution to minimize the energy cost of phyllotaxis transition. This model accounts for not only the high precision of the golden angle but also the occurrences of other angles observed in nature. The model also effectively explains the observed diversity of rational and irrational numbers in phyllotaxis.
Determination of basic friction angle using various laboratory tests.
Jang, Bo-An
2016-04-01
The basic friction angle of rock is an important factor of joint shear strength and is included within most shear strength criteria. It can be measured by direct shear test, triaxial compression test and tilt test. Tilt test is mostly used because it is the simplest method. However, basic friction angles measured using tilt test for same rock type or for one sample are widely distributed and often do not show normal distribution. In this research, the basic friction angles for the Hangdeung granite form Korea and Berea sandstone from USA are measured accurately using direct shear test and triaxial compression test. Then basic friction angles are again measured using tilt tests with various conditions and are compared with those measured using direct shear test and triaxial compression test to determine the optimum condition of tilt test. Three types of sliding planes, such as planes cut by saw and planes polished by #100 and #600 grinding powders, are prepared. When planes are polished by #100 grinding powder, the basic friction angles measured using direct shear test and triaxial compression test are very consistent and show narrow ranges. However, basic friction angles show wide ranges when planes are cut by saw and are polished by #600 grinding powder. The basic friction angle measured using tilt test are very close to those measured using direct shear test and triaxial compression test when plane is polished by #100 grinding powder. When planes are cut by saw and are polished by #600 grinding powder, basic friction angles measured using tilt test are slightly different. This indicates that tilt test with plane polished by #100 grinding powder can yield an accurate basic friction angle. In addition, the accurate values are obtained not only when planes are polished again after 10 times of tilt test, but values are averaged by more 30 times of tests.
Algorithms of wave reflective critical angle on interface
Zhang, YongGang; Zhang, JianXue; Jiao, Lin; Li, Qinghong
2017-02-01
This article is in connection with calculating of reflection critical angle on interface, author has found that reflective wave have a quarter wavelength effects and deduced both absolute and relative reflection critical Angle calculation formulas. The two formulas can easy solve the question of reflection critical angle on interface of one side of the air where it is not calculated by Snell's law. Snell's law only reveals that rate of the wave velocity projected to the interface, the methods of this paper reveal the normal component of wave velocity on the interface relationship. The methods will be widely used in various fields such as light, electromagnetic waves, sound waves and water waves etc.
Research of the Pressure Angle for Whole Cycloidal Gears
LIU Ling-tao; WANG Jian-hua
2011-01-01
The working profile of whole cycloidal gear is made up of epicycloid and hypocycloid entirely, according to the theory of meshing of gears and the properties of the cycloid, deals with the derivation of the pressure angle formula for the whole cycloidal gear in theory, and reveals changes of the pressure angle of whole cycloidal gear through examples, finds the application relationships between the pressure angle and other design parameters of the whole cycloidal gear, proves the possibility that the whole cycloidal gear can be used in internal parallel move gear mechanism, also provides theoretic fundament for designing internal parallel move whole cycloidal gear correctly.
Primary cerebello-pontine angle malignant melanoma : a case report.
Desai K
2001-04-01
Full Text Available A rare case of primary malignant melanoma in the cerebello-pontine angle, in a 17 year old girl is presented. The patient presented with one month history of headache, diplopia, facial asymmetry and ataxia. The computerised tomography (CT scan and magnetic resonance imaging (MRI revealed a large cerebello-pontine angle mass with features suggestive of a melanoma. The typical black coloured, solid and vascular melanoma was excised completely. Cerebello-pontine angle melanoma are extremely rare tumours with dismal long term outcome in majority of these cases.
Control of Angular Intervals for Angle-Multiplexed Holographic Memory
Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki
2009-03-01
In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.
Projection angles of mandibular condyles in panoramic and transcranial radiographs
Nah, Kyung Soo [Pusan National Univ. College of Dentistry, Pusan (Korea, Republic of)
2006-09-15
To evaluate the true projection angles of film-side mandibular condyles in panoramic and transcranial radiographs. 52 panoramic and transcranial radiographs of 4 condyles from two human dry mandibles with gradual horizontal and vertical angle changes were taken. The results were compared with the standard panoramic and transcranial radiographs and the identical pairs were selected. Panoramic radiography projected 10 degree to the film-sided condyles both horizontally and vertically. Transcranial radiography projected 15 degree to the film-sided condyles vertically. The medical and lateral poles were not forming the outline of condylar images in both projections when the horizontal angles of condyles were not sufficiently big enough.
Measurement of Critical Contact Angle in a Microgravity Space Experiment
Concus, P.; Finn, R.; Weislogel, M.
1998-01-01
Mathematical theory predicts that small changes in container shape or in contact angle can give rise to large shifts of liquid in a microgravity environment. This phenomenon was investigated in the Interface Configuration Experiment on board the USMT,2 Space Shuttle flight. The experiment's "double proboscis" containers were designed to strike a balance between conflicting requirements of sizable volume of liquid shift (for ease of observation) and abruptness of the shift (for accurate determination of critical contact angle). The experimental results support the classical concept of macroscopic contact angle and demonstrate the role of hysteresis in impeding orientation toward equilibrium.
Research advances on multifocal electroretinogram in primary open angle glaucoma
Feng-Fei Mo
2013-10-01
Full Text Available Primary open angle glaucoma is a chronic and progressive optic neuropathy. It can lead to serious damage of visual impairment, and it is an important eye disease of blindness. Multifocal electroretinogram is a new way to measure visual electrophysiology. It can measure electroretinogram of the whole visual field of many small parts in a relatively short period of time, and it can reflect the function of regional retina. It has an extremely important value for early diagnosis of primary open angle glaucoma. The research advances on multifocal electroretinogram in diagnosing primary open angle glaucoma were summarized in this paper.
Evaluation of the nasolabial angle in the Indian population
Vinay Dua
2010-01-01
Full Text Available Nasolabial angle has become the angle depicting the esthetics so has attained the prime importance in the treatment planning. Dr Jay P. Fitzgerland and Dr. Ram S. Nanda. In 1992 gave norms for Caucasian population. A radiographic cephalometric study was undertaken with 45 subjects of Indian origin to evaluate and compare with their result. The method of evaluation was according to the criteria given by Dr. Jay P Fitzergerald in AJODO 1992; 102:328-34. Significant decrease in nasolabial angle values was found in case of Indian population as compared to white adults.
The modified Cassie’s equation and contact angle hysteresis
Xu, Xianmin
2012-08-29
In this paper, we derive a modified Cassie\\'s equation for wetting on chemically patterned surfaces from a homogenization approach. The derivation reveals that effective contact angle is a local average of the static contact angle along the contact line which describes all possible equilibrium states including the local minimum of the free energy of the system. The usual Cassie\\'s state which corresponds to the global minimum is only a special case. We then discuss the contact angle hysteresis on chemically patterned surfaces. © 2012 Springer-Verlag.
Remote logo detection using angle-distance histograms
Youn, Sungwook; Ok, Jiheon; Baek, Sangwook; Woo, Seongyoun; Lee, Chulhee
2016-05-01
Among all the various computer vision applications, automatic logo recognition has drawn great interest from industry as well as various academic institutions. In this paper, we propose an angle-distance map, which we used to develop a robust logo detection algorithm. The proposed angle-distance histogram is invariant against scale and rotation. The proposed method first used shape information and color characteristics to find the candidate regions and then applied the angle-distance histogram. Experiments show that the proposed method detected logos of various sizes and orientations.
Evaluation of the nasolabial angle in the Indian population.
Dua, Vinay; Gupta, Shilpa; Singh, Chanjyot
2010-04-01
Nasolabial angle has become the angle depicting the esthetics so has attained the prime importance in the treatment planning. Dr Jay P. Fitzgerland and Dr. Ram S. Nanda. In 1992 gave norms for Caucasian population. A radiographic cephalometric study was undertaken with 45 subjects of Indian origin to evaluate and compare with their result. The method of evaluation was according to the criteria given by Dr. Jay P Fitzergerald in AJODO 1992; 102:328-34. Significant decrease in nasolabial angle values was found in case of Indian population as compared to white adults.
Drop Size Dependence of the Contact Angle of Nanodroplets
GUO Hong-Kai; FANG Hai-Ping
2005-01-01
@@ The contact angle of nanosized non-polarized argon sessile droplets on a solid substrate is studied by using molecular dynamics simulations.It is found that the drop size dependence of the contact angle is sensitive to the interaction between the liquid molecules and solid molecules.The contact angle decreases with the decreasing drop size for larger interaction between the liquid molecules and the solid substrate, and vice versa.This observation is consistent with most of the previous theoretical and experimental results.
Determination of the position angle of stellar spin axes
Lesage, Anna-Lea
2014-01-01
Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis of high resolution long-slit spectra. The method has been designed in particular for slowly rotating stars. We investigate its applicability to existing dispersive long-slit spectrographs, identified here by their plate scale, and the size of the resulting stellar sample. The stellar rotation induces a tilt in the stellar lines whose angle depends on the stellar position angle and the orientation of the slit. We developed a rotation model to calculate and reproduce the effects of stellar rotation on unreduced high resolution stellar spectra. Then we retrieved the tilt amplitude using a spectro-astrometric extraction of the position of the photocentre of the spectrum. Finally we present two methods for analysing the position spectrum using either direct measurement of the t...
Characteristics of Rotary Electromagnet with Large Tooth-pitch Angle
Ruan Jian
2012-10-01
Full Text Available Since the conventional electro-mechanical converter of 2D valve had problems of step lose due to its small tooth-pitch angle, a novel rotary electromagnet with large tooth-pitch angle and coreless rotor structure was proposed. Combined with the approaches of magnetic circuit analysis, finite element simulation and experimental study, the static and dynamic characteristics of electromagnet including torque-angle characteristics, frequency response and step response were studied. The experimental results are in a close agreement with the simulated results. The electromagnet has sinusoidal torque-angle characteristics and good dynamic response. The maximum static torque is approximately 0.083N.M, and its frequency width is about 125Hz/-3dB, 130Hz/-90°, respectively, and the rise time is about 5.5 ms. It is appropriate to be used as the electro-mechanical converter of 2D proportional valve.
Aerial wetting contact angle measurement using confocal microscopy
Chesna, Jacob W.; Wiedmaier, Bob F.; Wang, Jinlin; Samara, Ayman; Leach, Richard K.; Her, Tsing-Hua; Smith, Stuart T.
2016-12-01
A method is presented in which the wetting contact angle of a sessile drop is acquired aerially using confocal techniques to measure the radius and the height of a droplet deposited on a planar surface. The repeatability of this method is typically less than 0.25°, and often less than 0.1°, for droplet diameters less than 1 mm. To evaluate accuracy of this method, an instrument uncertainty budget is developed, which predicts a combined uncertainty of 0.91° for a 1 mm diameter water droplet with a contact angle of 110°. For droplets having diameters less than 1 mm and contact angles between 15° and 160°, these droplets approach spherical shape and their contact angles can be computed analytically with less than 1% error. For larger droplets, gravitational deformation needs to be considered.
Polarization Position Angle Swings caused by Relativistic Effects
无
2003-01-01
Polarization position angle swings of ～ 180° observed in extragalacticradio sources are a regular behavior of variability in polarization. They shouldbe due to some kind of physically regular process. We consider relativistic shocksproducing polarization angle swing events. Two magnetic field configurations (force-free field and homogeneous helical field) are considered to demonstrate the results.It is shown that the properties of polarization angle swings and the relationshipbetween the swings and variations in total and polarized flux density are criticallydependent on the configuration of magnetic field and the dynamical behavior of theshock. In particular, we find that in some cases polarization angle swings can occurwhen the total and polarized flux densities only vary by a very small amount. Theseresults may be useful for understanding the polarization variability with both longand short timescales observed in extragalactic radio sources.
ILC Extraction Line for 14 mrad Crossing Angle
Nosochkov, Y.; Markiewicz, T.; Maruyama, T.; Seryi, A.; /SLAC; Parker, B.; /Brookhaven
2005-12-08
The earlier studies of the ILC extraction line for 20 mrad and 2 mrad crossing angle options [1]-[5] showed that the 20 mrad design has an advantage of a simpler beamline and lower extraction beam loss because of the independent incoming and extraction optics. However, the large 20 mrad crossing angle requires the use of a crab cavity correction, increases synchrotron radiation emittance growth in the solenoid, and increases photon backscattering from the forward calorimeter of the detector. To reduce these effects, an attempt has been made to minimize the crossing angle while keeping the extraction and incoming lines separate. A new quadrupole scheme near the interaction point has been proposed which allows a reduction of the crossing angle to 14 mrad [6]. The optics design and results of tracking and background simulations for the 14 mrad extraction line are presented.
Parameterization of ion channeling half-angles and minimum yields
Doyle, Barney L.
2016-03-15
A MS Excel program has been written that calculates ion channeling half-angles and minimum yields in cubic bcc, fcc and diamond lattice crystals. All of the tables and graphs in the three Ion Beam Analysis Handbooks that previously had to be manually looked up and read from were programed into Excel in handy lookup tables, or parameterized, for the case of the graphs, using rather simple exponential functions with different power functions of the arguments. The program then offers an extremely convenient way to calculate axial and planar half-angles, minimum yields, effects on half-angles and minimum yields of amorphous overlayers. The program can calculate these half-angles and minimum yields for 〈u v w〉 axes and [h k l] planes up to (5 5 5). The program is open source and available at (http://www.sandia.gov/pcnsc/departments/iba/ibatable.html).
Multi-angle Imaging SpectroRadiometer (MISR)
National Aeronautics and Space Administration — The Multi-angle Imaging SpectroRadiometer (MISR) was successfully launched into sun-synchronous polar orbit aboard Terra, NASA's first Earth Observing System (EOS)...
Uncertainty Relation between Angular Momentum and Angle Variable.
Roy, C. L.; Sannigrahi, A. B.
1979-01-01
Discusses certain pitfalls regarding the uncertainty relation between angular momentum and the angle variable from a pedagogic point of view. Further, an uncertainty relation has been derived for these variables in a simple and consistant manner. (Author/HM)
On the uniformity of films fabricated by glancing angle deposition
Wakefield, Nicholas G.; Sit, Jeremy C.
2011-04-01
Films fabricated using the glancing angle deposition technique are subject to significant variations in several important film parameters across a sample due to geometric conditions that are not uniform across the substrate. This paper presents a method to quantify the non-uniformities in these quantities, starting from a generalized geometric framework, for low-pressure, physical vapor deposition of thin films on substrates of arbitrary size and position. This method is applicable to any glancing angle deposition setup including substrate tilt and rotation but focuses on the case of constant deposition angle and arbitrary azimuthal rotation. While some quantities, such as the effective deposition angle and the deposited mass per unit area at any given point on the substrate can be determined purely from the geometry of the deposition setup, obtaining further quantities, such as the film density and thickness, requires additional, material-specific information that is easily measured.
On Ruby's solid angle formula and some of its generalizations
Friot, Samuel
2014-01-01
Using the Mellin-Barnes representation, we show that Ruby's solid angle formula and some of its generalizations may be expressed in a compact way in terms of the Appell F4 and Lauricella Fc functions.
Modeling contact angle hysteresis on chemically patterned and superhydrophobic surfaces.
Kusumaatmaja, H; Yeomans, J M
2007-05-22
We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasistatically increased and decreased. We consider both two (cylindrical drops) and three (spherical drops) dimensions using analytical and numerical approaches to minimize the free energy of the drop. In two dimensions, we find, in agreement with other authors, a slip, jump, stick motion of the contact line. In three dimensions, this behavior persists, but the position and magnitude of the contact line jumps are sensitive to the details of the surface patterning. In two dimensions, we identify analytically the advancing and receding contact angles on the different surfaces, and we use numerical insights to argue that these provide bounds for the three-dimensional cases. We present explicit simulations to show that a simple average over the disorder is not sufficient to predict the details of the contact angle hysteresis and to support an explanation for the low contact angle hysteresis of suspended drops on superhydrophobic surfaces.
Can dynamic contact angle be measured using molecular modeling?
Malani, Ateeque; Raghavanpillai, Anilkumar; Wysong, Ernest B; Rutledge, Gregory C
2012-11-02
A method is presented for determining the dynamic contact angle at the three-phase contact between a solid, a liquid, and a vapor under an applied force, using molecular simulation. The method is demonstrated using a Lennard-Jones fluid in contact with a cylindrical shell of the fcc Lennard-Jones solid. Advancing and receding contact angles and the contact angle hysteresis are reported for the first time by this approach. The increase in force required to wet fully an array of solid cylinders (robustness) with decreasing separation distance between cylinders is evaluated. The dynamic contact angle is characterized by partial slipping of the three phase contact line when a force is applied.
Flow tilt angles near forest edges - Part 1: Sonic anemometry
Dellwik, Ebba; Mann, Jakob; Larsen, Klaus Steenberg
2010-01-01
-sets. These features of the investigated sonic anemometers make them unsuitable for measuring vertical velocities over highly turbulent forested terrain. By comparing the sonic anemometer results to that of a conically scanning Doppler lidar (Dellwik et al., 2010b), sonic anemometer accuracy for measuring mean flow...... distortion and vertical alignment, it was only possible to a limited extent to relate sonic anemometer flow tilt angles to upwind forest edges, but the results by the lidar indicated that an internal boundary layer affect flow tilt angles at 21m above the forest. This is in accordance with earlier studies......An analysis of flow tilt angles from a fetch-limited beech forest site with clearings is presented in the context of vertical advection of carbon dioxide. Flow angles and vertical velocities from two sonic anemometers by different manufacturers were analyzed. Instead of using rotations, where zero...
Folded cavity angled-grating broad-area lasers.
Zhao, Yunsong; Zhu, Lin
2013-10-01
The angled-grating broad-area laser is a promising candidate for high power, high brightness diode laser source. The key point in the design is the angled gratings which can simultaneously support the unique snake-like zigzag lasing mode and eliminate the direct Fabry-Perot (FP) feedback. Unlike a conventional laser waveguide mode, the phase front of the zigzag mode periodically changes along the propagation direction. By use of the mirror symmetry of the zigzag mode, we propose and demonstrate the folded cavity angled-grating broad-area lasers. One benefit of this design is to reduce the required wafer space compared to a regular angled-grating broad-area laser, especially in a long cavity laser for high power operation. Experimental results show that the folded cavity laser exhibits good beam quality in far field with a slightly larger threshold and smaller slope efficiency due to the additional interface loss.
Setting of angles on machine tools speeded by magnetic protractor
Vale, L. B.
1964-01-01
An adjustable protractor facilitates transference of angles to remote machine tools. It has a magnetic base incorporating a beam which can be adjusted until its shadow coincides with an image on the screen of a projector.
First statistics of the isopistonic angle for long baseline interferometry
Ziad, A.; Elhalkouj, T.; Petrov, R. G.; Borgnino, J.; Lazrek, M.; Benkhaldoun, Z.; Martin, F.; Elazhari, Y.
2016-06-01
To reach a suitable limiting magnitude with a multi-aperture interferometer, we need to cophase the different telescopes using a reference source. The latter should be located in the same isopistonic domain as the science source. We developed a direct analytical expression of deducing the isopistonic angle from atmospheric optical parameters as seeing, isoplanatic angle and outer scale. All of these atmospheric turbulence parameters are measured by the Generalized Seeing Monitor (GSM). The first statistics of the isopistonic angle obtained from the GSM data are presented and comparison between the major sites over the world are discussed (La Silla, Cerro Pachon, Paranal, San Pedro, Mt Palomar, Mauna Kea, La Palma, Oukaïmeden, Maydanak, Dome C). Implications of these isopistonic angle statistics on large interferometers cophasing in terms of sky coverage and limiting magnitude are discussed.
Bond Angles in the Crystalline Silicon/Silicon Nitride Interface
Leonard, Robert H.; Bachlechner, Martina E.
2006-03-01
Silicon nitride deposited on a silicon substrate has major applications in both dielectric layers in microelectronics and as antireflection and passivation coatings in photovoltaic applications. Molecular dynamic simulations are performed to investigate the influence of temperature and rate of externally applied strain on the structural and mechanical properties of the silicon/silicon nitride interface. Bond-angles between various atom types in the system are used to find and understand more about the mechanisms leading to the failure of the crystal. Ideally in crystalline silicon nitride, bond angles of 109.5 occur when a silicon atom is at the vertex and 120 angles occur when a nitrogen atom is at the vertex. The comparison of the calculated angles to the ideal values give information on the mechanisms of failure in silicon/silicon nitride system.
Shrinkage and trajectory of the flat jet with inclination angle
Shufeng Ye; Yusheng Xie; Hongzhi Guo; Ye Huang; Shantong Jin
2003-01-01
The performance of the flat jet with an inclination angle was investigated by a water model. A mathematical model for theshrinkage and the trajectory of the flat jet with an inclination angle was derived theoretically and verified by experimental data of thewater model. The experimental results indicate that the inclination angle (α) has no influence on the shrinkage of the flat jet, theshrinkage of the flat jet along the width direction decreases with the increasing of the initial velocity at the exit (u0) and the initialthickness of the flat jet (t0). Enough bigger initial exit velocity (u0) and initial thickness can suppress the shrinkage of the flat jetalong the width direction and keep the flat jet stabilized. In addition, the trajectory of the flat jet with an inclination angle is parabolicand must be taking into consideration when to determine the striking distance.
Generalized parton distributions and wide-angle exclusive scattering
Kroll, P
2004-01-01
The handbag mechanism for wide-angle exlusive scattering reactions is discussed and compared with other theoretical approaches. Its application to Compton scattering, meson photoproduction and two-photon annihilations into pairs of hadrons is reviewed.
Dynamic contact angle analysis of silicone hydrogel contact lenses.
Read, Michael Leonard; Morgan, Philip Bruce; Kelly, Jeremiah Michael; Maldonado-Codina, Carole
2011-07-01
Contact angle measurements are used to infer the clinical wetting characteristics of contact lenses. Such characterization has become more commonplace since the introduction of silicone hydrogel contact lens materials, which have been associated with reduced in vivo wetting due to the inclusion of siloxane-containing components. Using consistent methodology and a single investigator, advancing and receding contact angles were measured for 11 commercially available silicone hydrogel contact lens types with a dynamic captive bubble technique employing customized, fully automated image analysis. Advancing contact angles were found to range between 20° and 72° with the lenses falling into six statistically discrete groupings. Receding contact angles fell within a narrower range, between 17° and 22°, with the lenses segregated into three groups. The relationship between these laboratory measurements and the clinical performance of the lenses requires further investigation.
Evaluation of the correlation of ramus height, gonial angle, and ...
... gonial angle, and dental height with different facial forms in individuals with ... Abstract. Background: Restoring the vertical dimension is a critical procedure in ... statistically with one way analysis of variance and regression correlation test.
"Angle" Operator Conjugate to Photon's Intrinsic Angular Momentum
范洪义
2001-01-01
We find the correct "angle" operator conjugate to the intrinsic angular momentum of the photon by introducing a suitable representation which involves both left-handed and right-handed polarization photon operators.
Bistatic MIMO Radar Clutter Suppression by Exploiting the Transmit Angle
Li Jun
2014-04-01
Full Text Available The transmit angle of bistatic radars can be obtained by introducing Multiple-Input Multiple-Output (MIMO radar techniques. The Three-Dimensional (3D clutter spectra, that is, the transmit angle, receive angle, and Doppler frequency, are introduced using the additional angle information to Space-Time Adaptive Processing (STAP. This study reviews the researches on bistatic MIMO-STAP. 3D space-time adaptive processing methods for airborne bistatic side-looking MIMO radars, such as 3D-LCMV, 3D-ACR, 3D-JDL, and 3D projection-based reduced dimensional STAP methods, are discussed. Simulation results show that the proposed methods can improve the small-sample support performance of range-dependent clutter suppression in bistatic side-looking MIMO radar. Finally, the results are summarized and the prospects of bistatic MIMO-STAP are discussed.
Angle-resolved neutralization-reionization mass spectrometry.
Fura, A; Turecek, F; McLafferty, F W
1991-12-01
Neutralization -reionization mass spectra of 2-propenal, isomeric butenes, and isomeric n-hexenes have been found to depend significantly on the z-axis scattering angle of the neutralization event. As shown by Cooks for ion dissociations, increasing scattering angles generally favor products of higher activation-energy reactions. For isomeric butenes and n-hexenes, these reactions provide more definitive information for isomeric characterization.
Landweber Iterative Methods for Angle-limited Image Reconstruction
Gang-rong Qu; Ming Jiang
2009-01-01
We introduce a general itcrative scheme for angle-limited image reconstruction based on Landwe-ber's method. We derive a representation formula for this scheme and consequently establish its convergence conditions. Our results suggest certain relaxation strategies for an accelerated convergcnce for angle-limited im-age reconstruction in L2-norm comparing with alternative projection methods. The convolution-backprojection algorithm is given for this iterative process.
Pitch angle scattering of energetic particles by oblique whistler waves
Inan, U. S.; Bell, T. F.
1991-01-01
First order cyclotron or Landau resonant pitch angle scattering of electrons by oblique whistler waves propagating at large angles to the ambient field are found to be at least as large as that due to parallel propagating waves. Commonly observed precipitation of more than 40 keV electrons in association with ducted whistlers may thus be accompanied by substantial fluxes of lower energy (10 eV-40 keV) electrons precipitated by the nonducted components.
Measurement of the angle of superficial tension by images
Yanez M., Javier; Alonso R., Sergio
2006-02-01
When a liquid is deposited on a surface, this one form a certain angle with respect to the surface, where depending on its value, it will conclude that so hard it is his adhesion with the surface. By means of the analysis of images we looked for to measure this angle of superficial tension. In order to make this measurement, we propose a technique by means of projective transformations and one method of regression to estimation parameters to conic fitting.
A spin- and angle-resolving photoelectron spectrometer
Berntsen, M H; Leandersson, M; Hahlin, A; hlund, J \\AA; Wannberg, B; nsson, M M\\aa; Tjernberg, O
2010-01-01
A new type of hemispherical electron energy analyzer that permits angle and spin resolved photoelectron spectroscopy has been developed. The analyzer permits standard angle resolved spectra to be recorded with a two-dimensional detector in parallel with spin detection using a mini-Mott polarimeter. General design considerations as well as technical solutions are discussed and test results from the Au(111) surface state are presented.
Determining pitch-angle diffusion coefficients from test particle simulations
Ivascenko, A.; S. Lange; Spanier, F.; R. Vainio
2016-01-01
Transport and acceleration of charged particles in turbulent media is a topic of great interest in space physics and interstellar astrophysics. These processes are dominated by the scattering of particles off magnetic irregularities. The scattering process itself is usually described by small-angle scattering with the pitch-angle coefficient $D_{\\mu\\mu}$ playing a major role. Since the diffusion coefficient $D_{\\mu\\mu}$ can be determined analytically only for the approximation of quasi-linear...
Comparison of different passive knee extension torque-angle assessments.
Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro
2013-11-01
Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m(-2); tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome.
Contact angles in the pseudopotential lattice Boltzmann modeling of wetting
Li, Qing; Luo, K. H.; Kang, Q. J.; Chen, Q.
2014-11-01
In this paper we investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio ρL/ρV=500 . The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994), 10.1103/PhysRevE.49.2941] is a popular mesoscopic model for simulating multiphase flows and interfacial dynamics. In this model the contact angle is usually realized by a fluid-solid interaction. Two widely used fluid-solid interactions, the density-based interaction and the pseudopotential-based interaction, as well as a modified pseudopotential-based interaction formulated in the present paper are numerically investigated and compared in terms of the achievable contact angles, the maximum and the minimum densities, and the spurious currents. It is found that the pseudopotential-based interaction works well for simulating small static (liquid) contact angles θ static contact angles close to 180∘. Meanwhile, it is found that the proposed modified pseudopotential-based interaction performs better in light of the maximum and the minimum densities and is overall more suitable for simulating large contact angles θ >90∘ as compared with the two other types of fluid-solid interactions. Furthermore, the spurious currents are found to be enlarged when the fluid-solid interaction force is introduced. Increasing the kinematic viscosity ratio between the vapor and liquid phases is shown to be capable of reducing the spurious currents caused by the fluid-solid interactions.
A Universal Formula for Extracting the Euler Angles
Shuster, Malcolm D.; Markley, F. Landis
2004-01-01
Recently, the authors completed a study of the Davenport angles, which are a generalization of the Euler angles for which the initial and final Euler axes need not be either mutually parallel or mutually perpendicular or even along the coordinate axes. During the conduct of that study, those authors discovered a relationship which can be used to compute straightforwardly the Euler angles characterizing a proper-orthogonal direction-cosine matrix for an arbitrary Euler-axis set satisfying n(sub 1) x n(sub 2) = 0 and n(sub 3) x n(sub 1) = 0, which is also satisfied by the more usual Euler angles we encounter commonly in the practice of Astronautics. Rather than leave that relationship hidden in an article with very different focus from the present Engineering note, we present it and the universal algorithm derived from it for extracting the Euler angles from the direction-cosine matrix here. We also offer literal "code" for performing the operations, numerical examples, and general considerations about the extraction of Euler angles which are not universally known, particularly, the treatment of statistical error.
Proper Angle of Sono-guided Central Venous Line Insertion
Barzegari, Hassan; Forouzan, Arash; Fahimi, Mohammad Ali; Zohrevandi, Behzad; Ghanavati, Mandana
2016-01-01
Introduction: Determining the proper angle for inserting central venous catheter (CV line) is of great importance for decreasing the complications and increasing success rate. The present study was designed to determine the proper angle of needle insertion for internal jugular vein catheterization. Methods: In the present case series study, candidate patients for catheterization of the right internal jugular vein under guidance of ultrasonography were studied. At the time of proper placing of the catheter, photograph was taken and Auto Cad 2014 software was used to measure the angles of the needle in the sagittal and axial planes, as well as patient’s head rotation. Result: 114 patients with the mean age of 56.96 ± 14.71 years were evaluated (68.4% male). The most common indications of catheterization were hemodialysis (55.3%) and shock state (24.6%). The mean angles of needle insertion were 102.15 ± 6.80 for axial plane, 36.21 ± 3.12 for sagittal plane and the mean head rotation angle was 40.49 ± 5.09. Conclusion: Based on the results of the present study it seems that CV line insertion under the angles 102.15 ± 6.80 degrees in the axial plane, 36.21 ± 3.12 in the sagittal plane and 40.49 ± 5.09 head rotation yield satisfactory results. PMID:27299146
Contact angle of sessile drops in Lennard-Jones systems.
Becker, Stefan; Urbassek, Herbert M; Horsch, Martin; Hasse, Hans
2014-11-18
Molecular dynamics simulations are used for studying the contact angle of nanoscale sessile drops on a planar solid wall in a system interacting via the truncated and shifted Lennard-Jones potential. The entire range between total wetting and dewetting is investigated by varying the solid-fluid dispersive interaction energy. The temperature is varied between the triple point and the critical temperature. A correlation is obtained for the contact angle in dependence of the temperature and the dispersive interaction energy. Size effects are studied by varying the number of fluid particles at otherwise constant conditions, using up to 150,000 particles. For particle numbers below 10,000, a decrease of the contact angle is found. This is attributed to a dependence of the solid-liquid surface tension on the droplet size. A convergence to a constant contact angle is observed for larger system sizes. The influence of the wall model is studied by varying the density of the wall. The effective solid-fluid dispersive interaction energy at a contact angle of θ = 90° is found to be independent of temperature and to decrease linearly with the solid density. A correlation is developed that describes the contact angle as a function of the dispersive interaction, the temperature, and the solid density. The density profile of the sessile drop and the surrounding vapor phase is described by a correlation combining a sigmoidal function and an oscillation term.
Predicting bed form roughness: the influence of lee side angle
Lefebvre, Alice; Winter, Christian
2016-04-01
Flow transverse bedforms (ripples and dunes) are ubiquitous in rivers and coastal seas. Local hydrodynamics and transport conditions depend on the size and geometry of these bedforms, as they constitute roughness elements at the bed. Bedform influence on flow energy must be considered for the understanding of flow dynamics, and in the development and application of numerical models. Common estimations or predictors of form roughness (friction factors) are based mostly on data of steep bedforms (with angle-of-repose lee slopes), and described by highly simplified bedform dimensions (heights and lengths). However, natural bedforms often are not steep, and differ in form and hydraulic effect relative to idealised bedforms. Based on systematic numerical model experiments, this study shows how the hydraulic effect of bedforms depends on the flow structure behind bedforms, which is determined by the bedform lee side angle, aspect ratio and relative height. Simulations reveal that flow separation behind bedform crests and, thus, a hydraulic effect is induced at lee side angles steeper than 11 to 18° depending on relative height, and that a fully developed flow separation zone exists only over bedforms with a lee side angle steeper than 24°. Furthermore, the hydraulic effect of bedforms with varying lee side angle is evaluated and a reduction function to common friction factors is proposed. A function is also developed for the Nikuradse roughness (k s), and a new equation is proposed which directly relates k s to bedform relative height, aspect ratio and lee side angle.
Contact angle hysteresis on regular pillar-like hydrophobic surfaces.
Yeh, Kuan-Yu; Chen, Li-Jen; Chang, Jeng-Yang
2008-01-01
A series of pillar-like patterned silicon wafers with different pillar sizes and spacing are fabricated by photolithography and further modified by a self-assembled fluorosilanated monolayer. The dynamic contact angles of water on these surfaces are carefully measured and found to be consistent with the theoretical predictions of the Cassie model and the Wenzel model. When a water drop is at the Wenzel state, its contact angle hysteresis increases along with an increase in the surface roughness. While the surface roughness is further raised beyond its transition roughness (from the Wenzel state to the Cassie state), the contact angle hysteresis (or receding contact angle) discontinuously drops (or jumps) to a lower (or higher) value. When a water drop is at the Cassie state, its contact angle hysteresis strongly depends on the solid fraction and has nothing to do with the surface roughness. Even for a superhydrophobic surface, the contact angle hysteresis may still exhibit a value as high as 41 degrees for the solid fraction of 0.563.
OCULAR BIOMETRY IN ANGLE CLOSURE GLAUCOMA AND SENILE CATARACT
WANG Yu-lan; SHENG Yao-hua; YE Xiang-yu
2008-01-01
Objective To compare ocular biometric values in angle closure glaucoma and cataract in senile population.Methods Ocular biometry was performed in eyes classified to have angle closure glaucoma (29 eyes) and senile cataract (31 eyes). Ocular biometry readings between two groups were compared and analyzed statistically. Intraocular pressure was also recorded before and after lens extraction.Results Anterior chamber depth was shallower in patients with angle closure glaucoma group [(1.79±0.56) mm] compared with senile cataract group [(2.69±0.40) mm] (P<0.01). Lens thickness was greater in angle closure glaucoma group [(5.30±0.61) mm] than that in senile cataract group [(3.84±0.61) mm] (P<0.01). Phacoemusification was performed in 5 patients with persistent acute attack of angle closure glaucoma. IOPs were controlled in all five cases after lens extraction.Conclusion Eyes with angle closure glaucoma seems to have significantly shallow anterior chamber and greater lens thickness compared to senile cataract eyes in the same age. Lens extraction might be effective in those cases with such anatomy features.
Guidance law with impact time and impact angle constraints
Zhang Youan; Ma Guoxin; Liu Aili
2013-01-01
A novel closed-form guidance law with impact time and impact angle constraints is proposed for salvo attack of anti-ship missiles,which employs missile's normal acceleration (not jerk) as the control command directly.Firstly,the impact time control problem is formulated as tracking the designated time-to-go (the difference between the designated impact time and the current flight time) for the actual time-to-go of missile,and the impact angle control problem is formulated as tracking the designated heading angle for the actual heading angle of missile.Secondly,a biased proportional navigation guidance (BPNG) law with designated heading angle constraint is constructed,and the actual time-to-go estimation for this BPNG is derived analytically by solving the system differential equations.Thirdly,by adding a feedback control to this constructed BPNG to eliminate the time-to-go error-the difference between the standard time-to-go and the actual time-to-go,a guidance law with adjustable coefficients to control the impact time and impact angle simultaneously is developed.Finally,simulation results demonstrate the performance and feasibility of the proposed approach.
Angle-Resolved Plasmonic Properties of Single Gold Nanorod Dimers
Jian Wu; Xuxing Lu; Qiannan Zhu; Junwei Zhao; Qishun Shen; Li Zhan; Weihai Ni
2014-01-01
Through wet-chemical assembly methods, gold nanorods were placed close to each other and formed a dimer with a gap distance*1 nm, and hence degenerated plasmonic dipole modes of individual nanorods coupled together to produce hybridized bonding and antibonding resonance modes. Previous studies using a condenser for illumination result in averaged signals over all excitation angles. By exciting an individual dimer obliquely at different angles, we demonstrate that these two new resonance modes are highly tunable and sensitive to the angle between the excitation polarization and the dimer orientation, which follows cos2u dependence. Moreover, for dimer structures with various structure angles, the resonance wavelengths as well as the refractive index sensitivities were found independent of the structure angle. Cal-culated angle-resolved plasmonic properties are in good agreement with the measurements. The assembled nanostructures investigated here are important for fundamental researches as well as potential applications when they are used as building blocks in plasmon-based optical and optoelectronic devices.
Limbus Impact on Off-angle Iris Degradation
Karakaya, Mahmut [ORNL; Barstow, Del R [ORNL; Santos-Villalobos, Hector J [ORNL; Thompson, Joseph W [ORNL; Bolme, David S [ORNL; Boehnen, Chris Bensing [ORNL
2013-01-01
The accuracy of iris recognition depends on the quality of data capture and is negatively affected by several factors such as angle, occlusion, and dilation. Off-angle iris recognition is a new research focus in biometrics that tries to address several issues including corneal refraction, complex 3D iris texture, and blur. In this paper, we present an additional significant challenge that degrades the performance of the off-angle iris recognition systems, called the limbus effect . The limbus is the region at the border of the cornea where the cornea joins the sclera. The limbus is a semitransparent tissue that occludes a side portion of the iris plane. The amount of occluded iris texture on the side nearest the camera increases as the image acquisition angle increases. Without considering the role of the limbus effect, it is difficult to design an accurate off-angle iris recognition system. To the best of our knowledge, this is the first work that investigates the limbus effect in detail from a biometrics perspective. Based on results from real images and simulated experiments with real iris texture, the limbus effect increases the hamming distance score between frontal and off-angle iris images ranging from 0.05 to 0.2 depending upon the limbus height.
Hydrologic controls on junction angle of river networks
Hooshyar, Milad; Singh, Arvind; Wang, Dingbao
2017-05-01
The formation and growth of river channels and their network evolution are governed by the erosional and depositional processes operating on the landscape due to the movement of water. The branching angles, i.e., the angle between two adjoining channels, in drainage networks are important features related to the network topology and contain valuable information about the forming mechanisms of the landscape. Based on the channel networks extracted from 1 m Digital Elevation Models of 120 catchments with minimal human impacts across the United States, we show that the junction angles have two distinct modes with α1¯≈49.5° and α2¯≈75.0°. The observed angles are physically explained as the optimal angles that result in minimum energy dissipation and are linked to the exponent characterizing the slope-area curve. Our findings suggest that the flow regimes, debris-flow dominated or fluvial, have distinct characteristic angles which are functions of the scaling exponent of the slope-area curve. These findings enable us to understand the geomorphic signature of hydrologic processes on drainage networks and develop more refined landscape evolution models.
Equilibrium contact angles of liquid droplets on ideal rough solids.
Kang, Hie Chan; Jacobi, Anthony M
2011-12-20
This work proposes a theoretical model for predicting the apparent equilibrium contact angle of a liquid on an ideal rough surface that is homogeneous and has a negligible body force, line tension, or contact angle hysteresis between solid and liquid. The model is derived from the conservation equations and the free-energy minimization theory for the changes of state of liquid droplets. The work of adhesion is expressed as the contact angles in the wetting process of the liquid droplets. Equilibrium contact angles of liquid droplets for rough surfaces are expressed as functions of the area ratios for the solid, liquid, and surrounding gas and the roughness ratio and wetting ratio of the liquid on the solid for the partially and fully wet states. It is found that the ideal critical angle for accentuating the contact angles by the surface roughness is 48°. The present model is compared with existing experimental data and the classical Wenzel and Cassie-Baxter models and agrees with most of the experimental data for various surfaces and liquids better than does the Wenzel model and accounts for trends that the Wenzel model cannot explain.
Capillary rise with velocity-dependent dynamic contact angle.
Popescu, M N; Ralston, J; Sedev, R
2008-11-04
The classic description of the rate of capillary rise given by the Washburn equation, which assumes that the contact angle preserves the equilibrium value at all times, has been recently questioned in the light of the known experimental dependence of the dynamic contact angle on the velocity of the contact line. For a number of such proposed functions of velocity for the dynamic contact angle, we analyze the resulting dependences of the contact angle and of the time of rise, respectively, on the height of the capillary rise. By applying our results to the particular cases of a high-viscosity silicone oil and water, respectively, in a glass capillary, we show that, in general, strong similarities arise between the various approaches and the classic theory in what concerns the time dependence of the capillary rise, which explains the lack of consistent experimental evidence for deviations in the rate of capillary rise from the Washburn equation. However, for a strong dependency of the contact angle on the velocity in the range of small velocities, as in the case of water on glass, one of the models predicts significant deviations even for the time dependence of the capillary rise. Moreover, our results show that the time or height dependence of the contact angle during the capillary rise can clearly discriminate between the various models.
Measuring static and dynamic contact angles using a liquid needle
Sanedrin, Raymond; Jin, Ming; Frese, Daniel; Scheithauer, Carsten; Willers, Thomas
2016-11-01
The optical determination of static and advancing contact angle is made on drops applied or extended, respectively, onto a substrate through the use of thin solid needles. Although this method has been used extensively, this method of dosing can be time consuming, cumbersome and if not meticulously performed can lead to erroneous contact angle results. Herein, we present an alternative way of applying drops onto substrates using a small liquid jet, which is produced by a liquid pressure dosing system acting as a "liquid needle." A comparative static contact angle study on 14 different surfaces with two different liquids were performed utilizing two different ways of dosing: the conventional solid and a novel liquid needle based technique. We found, for all but one sample, that the obtained results were highly comparable. Observed differences can be explained by the characteristics of either way of dosing. In addition, we used the liquid pressure based dosing system for optical advancing contact angle measurement on two different samples. The liquid needle based method facilitates the expansion of a drop from 0.1 to 22 μL within less than 1.2 seconds, which provided constant contact angle versus drop base diameter curves. The obtained results were highly comparable with dynamic Wilhelmy contact angle measurements.
Contact angle and local wetting at contact line.
Li, Ri; Shan, Yanguang
2012-11-06
This theoretical study was motivated by recent experiments and theoretical work that had suggested the dependence of the static contact angle on the local wetting at the triple-phase contact line. We revisit this topic because the static contact angle as a local wetting parameter is still not widely understood and clearly known. To further clarify the relationship of the static contact angle with wetting, two approaches are applied to derive a general equation for the static contact angle of a droplet on a composite surface composed of heterogeneous components. A global approach based on the free surface energy of a thermodynamic system containing the droplet and solid surface shows the static contact angle as a function of local surface chemistry and local wetting state at the contact line. A local approach, in which only local forces acting on the contact line are considered, results in the same equation. The fact that the local approach agrees with the global approach further demonstrates the static contact angle as a local wetting parameter. Additionally, the study also suggests that the wetting described by the Wenzel and Cassie equations is also the local wetting of the contact line rather than the global wetting of the droplet.
An efficient magic state approach to small angle rotations
Campbell, Earl T.; O'Gorman, Joe
2016-12-01
Standard error-correction techniques only provide a quantum memory and need extra gadgets to perform computation. Central to quantum algorithms are small angle rotations, which can be fault-tolerantly implemented given a supply of an unconventional species of magic state. We present a low-cost distillation routine for preparing these small angle magic states. Our protocol builds on the work of Duclos-Cianci and Poulin (2015 Phys. Rev. A 91 042315) by compressing their circuit. Additionally, we present a method of diluting magic states that reduces costs associated with very small angle rotations. We quantify performance by the expected number of noisy magic states consumed per rotation, and compare with other protocols. For modest-sized angles, our protocols offer a factor 24 improvement over the best-known gate synthesis protocols and a factor 2 over the Duclos-Cianci and Poulin protocol. For very small angle rotations, the dilution protocol dramatically reduces costs, giving several orders magnitude improvement over competitors. There also exists an intermediary regime of small, but not very small, angles where our approach gives a marginal improvement over gate synthesis. We discuss how different performance metrics may alter these conclusions.
Determination of the Contact Angle Based on the Casimir Effect
Mazuruk, K.; Volz, M. P.
2015-01-01
In several crystal growth processed based on capillarity, a melt comes into contact with a crucible wall at an angle defined as the contact angle. For molten metals and semiconductors, this contact angle is dependent upon both the crucible and melt material and typical values fall in the range 80-170deg. However, on a microscopic scale, there does not exist a precise and sharp contact angle but rather the melt and solid surfaces merge smoothly and continuously over a distance of up to several micrometers. Accurate modeling requires a more advanced treatment of this interaction. The interaction between the melt and solid surfaces can be calculated by considering two forces: a short-range repulsive force and a longer range (up to a few micrometers) Casimir force. The Casimir force between the two bodies of complex geometry is calculated using a retarded temperature Green's function (Matsubara type) for the photon in the medium. The governing equations are cast in the form of a set of boundary integral equations which are then solved numerically for the case of molten Ge on SiO2. The shape of the molten surface approaching the flat solid body is determined, and the contact angle is defined as the angle between the two surfaces at the microscopically asymptotic distance of 1-2 micrometers. The formulation of this model and the results of the numerical calculations will be presented and discussed.
Evaluation of the nasolabial angle of the Komarapalayam population
Kohila Kandhasamy
2012-01-01
Full Text Available Esthetic features are different from one race to another, and this should be considered during the treatment planning. The great variance in soft tissue drape of the human face complicates accurate assessment. The nose-lip-chin relationships are exceedingly important in determining the facial esthetics. One important soft tissue parameter in orthodontic diagnosis is the nasolabial angle. The purpose of this study was to establish norms for nasolabial angle as proposed by Fitzgerald for the Komarapalayam population. Normative data for the three nasolabial parameters were produced from a sample of 40 (20 male and 20 female adults determined by the authors to have well-balanced faces. Mean and standard deviation values from this pooled sample demonstrated a lower border of the nose to Frankfort horizontal plane angle of 18° ± 7°, upper lip to Frankfort horizontal plane angle of 98° ± 5°, and nasolabial angle of 116° ± 10°. No statistically significant difference was demonstrated between the values for men and women in this study, but men did have a slightly larger nasolabial angle.
Influence of Contact Angle, Growth Angle and Melt Surface Tension on Detached Solidification of InSb
Wang, Yazhen; Regel, Liya L.; Wilcox, William R.
2000-01-01
We extended the previous analysis of detached solidification of InSb based on the moving meniscus model. We found that for steady detached solidification to occur in a sealed ampoule in zero gravity, it is necessary for the growth angle to exceed a critical value, the contact angle for the melt on the ampoule wall to exceed a critical value, and the melt-gas surface tension to be below a critical value. These critical values would depend on the material properties and the growth parameters. For the conditions examined here, the sum of the growth angle and the contact angle must exceed approximately 130, which is significantly less than required if both ends of the ampoule are open.
Assessment of angle velocity in girls with adolescent idiopathic scoliosis
Tejero Marta
2009-09-01
Full Text Available Abstract Background Although it has been demonstrated that the peak height velocity (PHV is a predictive factor of progression in adolescent idiopathic scoliosis (AIS, little is known about the usefulness of angle progression in clinical practice. The purpose of this study was to establish a relationship between height and angle velocities, as well as to determine if peak angle velocity (PAV occurs at the same time than PHV. Methods A retrospective study of a cohort of girls with idiopathic scoliotic curves greater than 10°. Data of 132 girls who participated in a previous retrospective study about growth in AIS were used to calculate height and angle velocities. Relationship between height and angle velocities was estimated by the use of a Linear Mixed Model. Results PHV and PAV take place simultaneously 1 year before menarche in progressive curves managed with a brace in AIS. Changes in angle velocity are influenced by changes in height growth velocity, in such a way that as from 6 months post-menarche, height growth velocity in this group of girls estimates curve progression velocity (β-coefficient -0.88, p = 0.04. Conclusion As from 6 months post-menarche, there is an inverse relationship between height velocity and curve progression in the group of AIS girls with progressive curves managed with a brace. Because height velocity is decreasing from 1 year before menarche, this finding corroborates that at the end of puberty, there is still a risk of progression in this group of girls despite bracing. The assessment of both height and angle velocity might be useful in clinical practice at the time of assessing brace effectiveness and how long bracing has to be indicated.
The human heart: application of the golden ratio and angle.
Henein, Michael Y; Zhao, Ying; Nicoll, Rachel; Sun, Lin; Khir, Ashraf W; Franklin, Karl; Lindqvist, Per
2011-08-04
The golden ratio, or golden mean, of 1.618 is a proportion known since antiquity to be the most aesthetically pleasing and has been used repeatedly in art and architecture. Both the golden ratio and the allied golden angle of 137.5° have been found within the proportions and angles of the human body and plants. In the human heart we found many applications of the golden ratio and angle, in addition to those previously described. In healthy hearts, vertical and transverse dimensions accord with the golden ratio, irrespective of different absolute dimensions due to ethnicity. In mild heart failure, the ratio of 1.618 was maintained but in end-stage heart failure the ratio significantly reduced. Similarly, in healthy ventricles mitral annulus dimensions accorded with the golden ratio, while in dilated cardiomyopathy and mitral regurgitation patients the ratio had significantly reduced. In healthy patients, both the angles between the mid-luminal axes of the pulmonary trunk and the ascending aorta continuation and between the outflow tract axis and continuation of the inflow tract axis of the right ventricle approximate to the golden angle, although in severe pulmonary hypertension, the angle is significantly increased. Hence the overall cardiac and ventricular dimensions in a normal heart are consistent with the golden ratio and angle, representing optimum pump structure and function efficiency, whereas there is significant deviation in the disease state. These findings could have anatomical, functional and prognostic value as markers of early deviation from normality. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Reliability of the ATD Angle in Dermatoglyphic Analysis.
Brunson, Emily K; Hohnan, Darryl J; Giovas, Christina M
2015-09-01
The "ATD" angle is a dermatoglyphic trait formed by drawing lines between the triradii below the first and last digits and the most proximal triradius on the hypothenar region of the palm. This trait has been widely used in dermatoglyphic studies, but several researchers have questioned its utility, specifically whether or not it can be measured reliably. The purpose of this research was to examine the measurement reliability of this trait. Finger and palm prints were taken using the carbon paper and tape method from the right and left hands of 100 individuals. Each "ATD" angle was read twice, at different times, by Reader A, using a goniometer and a magnifying glass, and three times by a Reader B, using Adobe Photoshop. Inter-class correlation coefficients were estimated for the intra- and inter-reader measurements of the "ATD" angles. Reader A was able to quantify ATD angles on 149 out of 200 prints (74.5%), and Reader B on 179 out of 200 prints (89.5%). Both readers agreed on whether an angle existed on a print 89.8% of the time for the right hand and 78.0% for the left. Intra-reader correlations were 0.97 or greater for both readers. Inter-reader correlations for "ATD" angles measured by both readers ranged from 0.92 to 0.96. These results suggest that the "ATD" angle can be measured reliably, and further imply that measurement using a software program may provide an advantage over other methods.
Controlling Compressor Vane Flow Vectoring Angles at Transonic Speeds
Munson, Matthew; Rempfer, Dietmar; Williams, David; Acharya, Mukund
2003-11-01
The ability to control flow separation angles from compressor inlet guide vanes with a Coanda-type actuator is demonstrated using both wind tunnel experiments and finite element simulations. Vectoring angles up to 40 degrees from the uncontrolled baseline state were measured with helium schlieren visualization at transonic Mach numbers ranging from 0.1 to 0.6, and with airfoil chord Reynolds numbers ranging from 89,000 to 710,000. The magnitude of the vectoring angle is shown to depend upon the geometry of the trailing edge, and actuator slot size, and the momentum flux coefficient. Under certain conditions the blowing has no effect on the vectoring angle indicating that the Coanda effect is not present. DNS simulations with the finite element method investigated the effects of geometry changes and external flow. Continuous control of the vectoring angle is demonstrated, which has important implications for application to rotating machinery. The technique is shown to reduce the stall flow coefficient by 15 percent in an axial flow compressor.
Determination of the Contact Angle Based on the Casimir Effect
Mazuruk, Konstantin; Volz, Martin P.
2015-01-01
On a macroscopic scale, a nonreactive liquid partially covering a homogeneous solid surface will intersect the solid at an angle called the contact angle. For molten metals and semiconductors, the contact angle is materially dependent upon both the solid and liquid and typical values fall in the range 80-170 deg, depending on the crucible material. On a microscopic scale, there does not exist a precise and sharp contact angle but rather the liquid and solid surfaces merge smoothly and continuously. Consider the example of the so called detached Bridgman crystal growth process. In this technique, a small gap is formed between the growing crystal and the crucible. At the crystal/melt interface, a meniscus ring is formed. Its width can be in the range of a few micrometers, approaching a microscopic scale. It then becomes questionable to describe the shape of this meniscus by the contact angle. A more advanced treatment of the interface is needed and here we propose such a refined model. The interaction of the liquid surface with the solid can be calculated by considering two forces: a short-range repulsive force and a longer range (up to a few micrometers) Casimir or van der Waals force.
High Pressure Angle Gears: Comparison to Typical Gear Designs
Handschuh, Robert F.; Zabrajsek, Andrew J.
2010-01-01
A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).
Contact angles of wetting and water stability of soil structure
Kholodov, V. A.; Yaroslavtseva, N. V.; Yashin, M. A.; Frid, A. S.; Lazarev, V. I.; Tyugai, Z. N.; Milanovskiy, E. Yu.
2015-06-01
From the soddy-podzolic soils and typical chernozems of different texture and land use, dry 3-1 mm aggregates were isolated and sieved in water. As a result, water-stable aggregates and water-unstable particles composing dry 3-1 mm aggregates were obtained. These preparations were ground, and contact angles of wetting were determined by the static sessile drop method. The angles varied from 11° to 85°. In most cases, the values of the angles for the water-stable aggregates significantly exceeded those for the water-unstable components. In terms of carbon content in structural units, there was no correlation between these parameters. When analyzing the soil varieties separately, the significant positive correlation between the carbon content and contact angle of aggregates was revealed only for the loamy-clayey typical chernozem. Based on the multivariate analysis of variance, the value of contact wetting angle was shown to be determined by the structural units belonging to water-stable or water-unstable components of macroaggregates and by the land use type. In addition, along with these parameters, the texture has an indirect effect.
Assessing manual lifting tasks based on segment angle interpolations.
Chang, Chien-Chi; Xu, Xu; Faber, Gert S; Kingma, Idsart; Dennerlein, Jack
2012-01-01
This study investigates the effects of the number of interpolation points on the prediction accuracy of segment angle trajectory during lifting. Ten participants performed various lifting tasks while a motion tracking system recorded their movements. Two-point through ten-point equal time-spaced segment angles extracted from major segment trajectory data captured by the motion tracking system were used to re-generate the whole body lifting motion by using polynomial and cubic spline interpolation methods. The root mean square error (RMSE) between the reference (motion tracking system) and the estimated (interpolation method) segment angle trajectories were calculated to quantify the prediction accuracy. The results showed that the cubic spline interpolation will yield a smaller RMSE value than one based on the polynomial interpolation. While increasing the number of interpolation points can reduce the RMSE of the estimated segment angle trajectories, there was a diminishing advantage in continuing to add interpolation points. A sensitivity analysis suggests that if the estimation of the segment angles at each interpolation point deviates considerably from the real value, and cannot be controlled at a low level (interpolation points will not improve the estimation accuracy.
Shoulder and elbow joint angle tracking with inertial sensors.
El-Gohary, Mahmoud; McNames, James
2012-09-01
Wearable inertial systems have recently been used to track human movement in and outside of the laboratory. Continuous monitoring of human movement can provide valuable information relevant to individuals' level of physical activity and functional ability. Traditionally, orientation has been calculated by integrating the angular velocity from gyroscopes. However, a small drift in the measured velocity leads to increasing integration error over time. To compensate that drift, complementary data from accelerometers are normally fused into tracking systems using the Kalman or extended Kalman filter. In this study, we combine kinematic models designed for control of robotic arms with state-space methods to continuously estimate the angles of human shoulder and elbow using two wearable inertial measurement units. We use the unscented Kalman filter to implement the nonlinear state-space inertial tracker. Shoulder and elbow joint angles obtained from 8 subjects using our inertial tracker were compared to the angles obtained from an optical-tracking reference system. On average, there was an RMS angle error of less than 8° for all shoulder and elbow angles. The average correlation coefficient for all movement tasks among all subjects was r ≥ 0.95 . This agreement between our inertial tracker and the optical reference system was obtained for both regular and fast-speed movement of the arm. The same method can be used to track movement of other joints.
Estimation of crank angle for cycling with a powered prosthesis.
Lawson, B E; Shultz, A; Ledoux, E; Goldfarb, M
2014-01-01
In order for a prosthesis to restore power generation during cycling, it must supply torque in a manner that is coordinated with the motion of the bicycle crank. This paper outlines an algorithm for the real time estimation of the angular position of a bicycle crankshaft using only measurements internal to an intelligent knee and ankle prosthesis. The algorithm assumes that the rider/prosthesis/bicycle system can be modeled as a four-bar mechanism. Assuming that a prosthesis can generate two independent angular measurements of the mechanism (in this case the knee angle and the absolute orientation of the shank), Freudenstein's equation can be used to synthesize the mechanism continuously. A recursive least-squares algorithm is implemented to estimate the Freudenstein coefficients, and the resulting link lengths are used to reformulate the equation in terms of input-output relationships mapping both measured angles to the crank angle. Using two independent measurements allows the algorithm to uniquely determine the crank angle from multi-valued functions. In order to validate the algorithm, a bicycle was mounted on a trainer and configured with the prosthesis using an artificial hip joint attached to the seat post. Motion capture was used to monitor the mechanism for forward and backward pedaling and the results are compared to the output of the presented algorithm. Once the parameters have converged, the algorithm is shown to predict the crank angle within 15° of the externally measured value throughout the entire crank cycle during forward rotation.
Determination of refractive index of various materials on Brewster angle
Tikhonov, Eugene A
2015-01-01
Studied experimentally the origin of the non-zero reflection of p-polarized radiation (TM) of Brewster's angle. The results have shown the residual reflected light in the vicinity of Brewster angle occurs due to inaccessibility 100% polarization degree the incident linearly-polarized radiation and installation of the zero azimuthal angle. These factors create the s-component of the radiation reflected from the examined surface indeed. A smooth change of reflected light polarization in the vicinity of Brewster angle in the sequence p-s-p appears due to the changing power proportion of reflected p-, and s-components but not is the result of the atomically thin transitional layer at the border of the material/environment according to Drude model. Metrological aspects of refractive index measurement by Brewster angle are investigated: due to the above-mentioned factors, as well as due to the contribution of the reflected scattered light caused by on residual roughness of the optical surface. Advantages of Brewste...
Low frequency seabed scattering at low grazing angles.
Zhou, Ji-Xun; Zhang, Xue-Zhen
2012-04-01
Low-frequency (LF) seabed scattering at low grazing angles (LGA) is almost impossible to directly measure in shallow water (SW), except through inversion from reverberation. The energy flux method for SW reverberation is briefly introduced in this paper. The closed-form expressions of reverberation in an isovelocity waveguide, derived from this method, indicate that in the three-halves law range interval multimode/ray sea bottom scattering with different incident and scattering angles in forming the reverberation may equivalently be represented by the bottom backscattering at a single range-dependent angle. This equivalent relationship is used to derive the bottom backscattering strength (BBS) as a function of angle and frequency. The LF&LGA BBS is derived in a frequency band of 200-2500 Hz and in a grazing angle range of 1.1°-14.0° from reverberation measurements at three sites with sandy bottoms. This is based on three previous works: (1) The closed-form expressions of SW reverberation [Zhou, (Chinese) Acta Acustica 5, 86-99 (1980)]; (2) the effective geo-acoustic model of sandy bottoms that follows the Biot model [Zhou et al., J. Acoust. Soc. Am. 125, 2847-2866 (2009)] and (3) A quality database of wideband reverberation level normalized to source level [Zhou and Zhang, IEEE J. Oceanic Eng. 30, 832-842 (2005)].
Modeling liquid bridge between surfaces with contact angle hysteresis.
Chen, H; Amirfazli, A; Tang, T
2013-03-12
This paper presents the behaviors of a liquid bridge when being compressed and stretched in a quasi-static fashion between two solid surfaces that have contact angle hysteresis (CAH). A theoretical model is developed to obtain the profiles of the liquid bridge given a specific separation between the surfaces. Different from previous models, both contact lines in the upper and lower surfaces were allowed to move when the contact angles reach their advancing or receding values. When the contact angles are between their advancing and receding values, the contact lines are pinned while the contact angles adjust to accommodate the changes in separation. Effects of CAH on both asymmetric and symmetric liquid bridges were analyzed. The model was shown to be able to correctly predict the behavior of the liquid bridge during a quasi-static compression/stretching loading cycle in experiments. Because of CAH, the liquid bridge can have two different profiles at the same separation during one loading and unloading cycle, and more profiles can be obtained during multiple cycles. The maximum adhesion force generated by the liquid bridge is found to be influenced by the CAH of surfaces. CAH also leads to energy cost during a loading cycle of the liquid bridge. In addition, the minimum separation between the two solid surfaces is shown to affect how the contact radii and angles change on the two surfaces as the liquid bridge is stretched.
Contact angle of a nanodrop on a nanorough solid surface.
Berim, Gersh O; Ruckenstein, Eli
2015-02-21
The contact angle of a cylindrical nanodrop on a nanorough solid surface is calculated, for both hydrophobic and hydrophilic surfaces, using the density functional theory. The emphasis of the paper is on the dependence of the contact angle on roughness. The roughness is modeled by rectangular pillars of infinite length located on the smooth surface of a substrate, with fluid-pillar interactions different in strength from the fluid-substrate ones. It is shown that for hydrophobic substrates the trend of the contact angle to increase with increasing roughness, which was noted in all previous studies, is not universally valid, but depends on the fluid-pillar interactions, pillar height, interpillar distance, as well as on the size of the drop. For hydrophilic substrate, an unusual kink-like dependence of the contact angle on the nanodrop size is found which is caused by the change in the location of the leading edges of the nanodrop on the surface. It is also shown that the Wenzel and Cassie-Baxter equations can not explain all the peculiarities of the contact angle of a nanodrop on a nanorough surface.
Fabrication of zero contact angle ultra-super hydrophilic surfaces.
Jothi Prakash, C G; Clement Raj, C; Prasanth, R
2017-01-05
Zero contact angle surfaces have been created with the combined effect of nanostructure and UV illumination. The contact angle of titanium surface has been optimized to 3.25°±1°. with nanotubular structures through electrochemical surface modification. The porosity and surface energy of tubular TiO2 layer play critical role over the surface wettability and the hydrophilicity of the surface. The surface free energy has been enhanced from 23.72mJ/m(2) (bare titanium surface) to 87.11mJ/m(2) (nanotubular surface). Similar surface with TiO2 nanoparticles coating shows superhydrophilicity with contact angle up to 5.63°±0.95°. This implies liquid imbibition and surface curvature play a crucial role in surface hydrophilicity. The contact angle has been further reduced to 0°±0.86° by illuminating the surface with UV radiation. Results shows that by tuning the nanotube morphology, highly porous surfaces can be fabricated to reduce contact angle and enhance wettability. This study provides an insight into the inter-relationship between surface structural factors and ultra-superhydrophilic surfaces which can help to optimize thermal hydraulic and self cleaning surfaces.
Repulsion-based model for contact angle saturation in electrowetting.
Ali, Hassan Abdelmoumen Abdellah; Mohamed, Hany Ahmed; Abdelgawad, Mohamed
2015-01-01
We introduce a new model for contact angle saturation phenomenon in electrowetting on dielectric systems. This new model attributes contact angle saturation to repulsion between trapped charges on the cap and base surfaces of the droplet in the vicinity of the three-phase contact line, which prevents these surfaces from converging during contact angle reduction. This repulsion-based saturation is similar to repulsion between charges accumulated on the surfaces of conducting droplets which causes the well known Coulombic fission and Taylor cone formation phenomena. In our model, both the droplet and dielectric coating were treated as lossy dielectric media (i.e., having finite electrical conductivities and permittivities) contrary to the more common assumption of a perfectly conducting droplet and perfectly insulating dielectric. We used theoretical analysis and numerical simulations to find actual charge distribution on droplet surface, calculate repulsion energy, and minimize energy of the total system as a function of droplet contact angle. Resulting saturation curves were in good agreement with previously reported experimental results. We used this proposed model to predict effect of changing liquid properties, such as electrical conductivity, and system parameters, such as thickness of the dielectric layer, on the saturation angle, which also matched experimental results.
Magnetically induced decrease in droplet contact angle on nanostructured surfaces.
Zhou, Qian; Ristenpart, William D; Stroeve, Pieter
2011-10-04
We report a magnetic technique for altering the apparent contact angle of aqueous droplets deposited on a nanostructured surface. Polymeric tubes with embedded superparamagnetic magnetite (Fe(3)O(4)) nanoparticles were prepared via layer-by-layer deposition in the 800 nm diameter pores of polycarbonate track-etched (PCTE) membranes. Etching away the original membrane yields a superparamagnetic film composed of mostly vertical tubes attached to a rigid substrate. We demonstrate that the apparent contact angle of pure water droplets deposited on the nanostructured film is highly sensitive to the ante situm strength of an applied magnetic field, decreasing linearly from 117 ± 1.3° at no applied field to 105 ± 0.4° at an applied field of approximately 500 G. Importantly, this decrease in contact angle did not require an inordinately strong magnetic field: a 15° decrease in contact angle was observed even with a standard alnico bar magnet. We interpret the observed contact angle behavior in terms of magnetically induced conformation changes in the film nanostructure, and we discuss the implications for reversibly switching substrates from hydrophilic to hydrophobic via externally tunable magnetic fields.
Adiabatic Berry Phase and Hannay Angle for Open Paths
Pati, A K
1998-01-01
We obtain the adiabatic Berry phase by defining a generalised gauge potential whose line integral gives the phase holonomy for arbitrary evolutions of parameters. Keeping in mind that for classical integrable systems it is hardly clear how to obtain open-path Hannay angle, we establish a connection between the open-path Berry phase and Hannay angle by using the parametrised coherent state approach. Using the semiclassical wavefunction we analyse the open-path Berry phase and obtain the open-path Hannay angle. Further, by expressing the adiabatic Berry phase in terms of the commutator of instantaneous projectors with its differential and using Wigner representation of operators we obtain the Poisson bracket between distribution function and its differential. This enables us to talk about the classical limit of the phase holonomy which yields the angle holonomy for open-paths. An operational definition of Hannay angle is provided based on the idea of classical limit of quantum mechanical inner product. A probab...
Scattering-angle based filtering of the waveform inversion gradients
Alkhalifah, Tariq Ali
2014-11-22
Full waveform inversion (FWI) requires a hierarchical approach to maneuver the complex non-linearity associated with the problem of velocity update. In anisotropic media, the non-linearity becomes far more complex with the potential trade-off between the multiparameter description of the model. A gradient filter helps us in accessing the parts of the gradient that are suitable to combat the potential non-linearity and parameter trade-off. The filter is based on representing the gradient in the time-lag normalized domain, in which the low scattering angle of the gradient update is initially muted out in the FWI implementation, in what we may refer to as a scattering angle continuation process. The result is a low wavelength update dominated by the transmission part of the update gradient. In this case, even 10 Hz data can produce vertically near-zero wavenumber updates suitable for a background correction of the model. Relaxing the filtering at a later stage in the FWI implementation allows for smaller scattering angles to contribute higher-resolution information to the model. The benefits of the extended domain based filtering of the gradient is not only it\\'s ability in providing low wavenumber gradients guided by the scattering angle, but also in its potential to provide gradients free of unphysical energy that may correspond to unrealistic scattering angles.
Automated measurement of diagnostic angles for hip dysplasia
de Raedt, Sepp; Mechlenburg, Inger; Stilling, Maiken; Rømer, Lone; Søballe, Kjeld; de Bruijne, Marleen
2013-03-01
A fully automatic method for measuring diagnostic angles of hip dysplasia is presented. The method consists of the automatic segmentation of CT images and detection of anatomical landmarks on the femur and acetabulum. The standard angles used in the diagnosis of hip dysplasia are subsequently automatically calculated. Previous work in automating the measuring of angles required the manual segmentation or delineation of the articular joint surface. In the current work automatic segmentation is established using graph-cuts with a cost function based on a sheetness score to detect the sheet-like structure of the bone. Anatomical landmarks are subsequently detected using heuristics based on ray-tracing and the distance to the approximated acetabulur joint surface. Standard diagnositic angles are finally calculated and presented for interpretation. Experiments using 26 patients, showed a good agreement with gold standard manual measurements by an expert radiologist as performed in daily practice. The mean difference for the five angles was between -1:1 and 2:0 degrees with a concordance correlation coefficient between 0:87 and 0:93. The standard deviation varied between 2:3 and 4:1 degrees. These values correspond to values found in evaluating interobserver and intraobserver variation for manual measurements. The method can be used in clinical practice to replace the current manual measurements performed by radiologists. In the future, the method will be integrated into an intraoperative surgical guidance system.
Estimation of Upper Limb Joint Angle Using Surface EMG Signal
Yee Mon Aung
2013-10-01
Full Text Available In the development of robot-assisted rehabilitation systems for upper limb rehabilitation therapy, human electromyogram (EMG is widely used due to its ability to detect the user intended motion. EMG is one kind of biological signal that can be recorded to evaluate the performance of skeletal muscles by means of a sensor electrode. Based on recorded EMG signals, user intended motion could be extracted via estimation of joint torque, force or angle. Therefore, this estimation becomes one of the most important factors to achieve accurate user intended motion. In this paper, an upper limb joint angle estimation methodology is proposed. A back propagation neural network (BPNN is developed to estimate the shoulder and elbow joint angles from the recorded EMG signals. A Virtual Human Model (VHM is also developed and integrated with BPNN to perform the simulation of the estimated angle. The relationships between sEMG signals and upper limb movements are observed in this paper. The effectiveness of our developments is evaluated with four healthy subjects and a VHM simulation. The results show that the methodology can be used in the estimation of joint angles based on EMG.
Rotating Shaft Tilt Angle Measurement Using an Inclinometer
Luo Jun
2015-10-01
Full Text Available This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.
Rotating Shaft Tilt Angle Measurement Using an Inclinometer
Luo, Jun; Wang, Zhiqian; Shen, Chengwu; Wen, Zhuoman; Liu, Shaojin; Cai, Sheng; Li, Jianrong
2015-10-01
This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.
The Influence of Dynamic Contact Angle on Wetting Dynamics
Rame, Enrique; Garoff, Steven
2005-01-01
When surface tension forces dominate, and regardless of whether the situation is static or dynamic, the contact angle (the angle the interface between two immiscible fluids makes when it contacts a solid) is the key parameter that determines the shape of a fluid-fluid interface. The static contact angle is easy to measure and implement in models predicting static capillary surface shapes and such associated quantities as pressure drops. By contrast, when the interface moves relative to the solid (as in dynamic wetting processes) the dynamic contact angle is not identified unambiguously because it depends on the geometry of the system Consequently, its determination becomes problematic and measurements in one geometry cannot be applied in another for prediction purposes. However, knowing how to measure and use the dynamic contact angle is crucial to determine such dynamics as a microsystem throughput reliably. In this talk we will present experimental and analytical efforts aimed at resolving modeling issues present in dynamic wetting. We will review experiments that show the inadequacy of the usual hydrodynamic model when a fluid-fluid meniscus moves over a solid surface such as the wall of a small tube or duct. We will then present analytical results that show how to parametrize these problems in a predictive manner. We will illustrate these ideas by showing how to implement the method in numerical fluid mechanical calculations.
Dynamic contact angles in oil-aqueous polymer solutions.
Al-Shareef, Amer; Neogi, P; Bai, Baojun
2017-01-25
Polymer flooding is an important process in enhanced oil recovery. The displacement front is unstable when low viscosity brine displaces the heavy crude oil in the reservoir. Water-soluble polymers are added to the brine to increase its viscosity which stabilizes the displacement process. To analyze the displacement process at the micro-level, we have investigated the dynamic contact angles in silicone oil-polymer (polyethylene oxide) solution and for the first time. The dynamic contact angle is the apparent contact angle at the three-phase contact line which governs the capillary pressure, and thus is important for the displacement process. The data show no obvious signs of either shear thinning or elastic behavior, although for some systems with highest elastic effects some unexplained effects on dynamic contact angles are observed that correlate with elastic effects. Overall, dynamic contact angles are explained well using existing models for two Newtonian fluids, when the zero shear viscosity is used for the polymer solution.
Wide-angle incidence and P-wave transmission
Xie, Jun-Fa; Sun, Cheng-Yu; Lin, Mei-Yan; Li, Jing-Jing
2015-12-01
Polarity reversals may occur to transmitted P waves if the incidence angle is greater than the critical incidence angle. We analyze the characteristics of reflection and transmission coefficients under the condition of wide incidence angle based on Zoeppritz equations. We find that for specific conditions, as the incidence angle increases, the characteristic curve of the transmitted P-wave coefficient enters the third quadrant from the first quadrant through the origin, which produces a transition in the transmitted P wave and the corresponding coefficient experiences polarity reversal. We derive the incidence angle when the transmitted P-wave coefficient is zero and verify that it equals zero by using finite-difference forward modeling for a single-interface model. We replace the water in the model reservoir by gas and see that the reservoir P-wave velocity and density decrease dramatically. By analyzing the synthetic seismogram of the transmitted P wave in the single-interface model, we show that the gas-saturated reservoir is responsible for polarity reversal.
Large optical field enhancement for nanotips with large opening angles
Thomas, Sebastian; Wachter, Georg; Lemell, Christoph; Burgdörfer, Joachim; Hommelhoff, Peter
2015-06-01
We theoretically investigate the dependence of the enhancement of optical near-fields at nanometric tips on the shape, size, and material of the tip. We confirm the strong dependence of the field enhancement factor on the radius of curvature. In addition, we find a surprisingly strong increase of field enhancement with increasing opening angle of the nanotips. For gold and tungsten nanotips in the experimentally relevant parameter range (radius of curvature ≥slant 5 nm at 800 nm laser wavelength), we obtain field enhancement factors of up to ∼ 35 for Au and ∼ 12 for W for large opening angles. We confirm this strong dependence on the opening angle for many other materials featuring a wide variety in their dielectric response. For dielectrics, the opening angle dependence is traced back to the electrostatic force of the induced surface charge at the tip shank. For metals, the plasmonic response strongly increases the field enhancement and shifts the maximum field enhancement to smaller opening angles.
Analysis of the changing Solar Radiation Angle on Hainan Island
Ge Zhiwu
2017-01-01
Full Text Available As the only tropical provinces in China, Hainan province has advantageous geographical location, and abundant solar energy resources. But because of Local ideas and habits, especially the lack of theoretical research on local solar resources, development and application of solar energy in Hainan is almost blank. In this paper, we studied the variation regularity of sunlight angle on Hainan tropical island, analyzed the revolution and rotation of the earth, and the change rule of sunlight angle caused by the sun’s movement between the tropic of cancer and the tropic of capricorn, deduced the change rule of sunlight angle in the spring equinox, the autumnal equinox, summer solstice and winter solstice day, and got the movement rules of solar elevation angle throughout the year. Theoretic analysis is consistent with field measurement results. These rules are of importance and can effectively guide the local People’s daily life and production, such as the reasonable layout of the buildings, floor distance between different heights of buildings, the direction of the lighting windows of tall buildings, installation angle of photovoltaic panels, and other similar solar energy absorbing and conversion equipment.
Large-area, wide-angle, spectrally selective plasmonic absorber
Wu, Chihhui; John, Jeremy; Milder, Andrew; Zollars, Byron; Savoy, Steve; Shvets, Gennady
2011-01-01
A simple metamaterial-based wide-angle plasmonic absorber is introduced, fabricated, and experimentally characterized using angle-resolved infrared spectroscopy. The metamaterials are prepared by nano-imprint lithography, an attractive low-cost technology for making large-area samples. The matching of the metamaterial's impedance to that of vacuum is responsible for the observed spectrally selective "perfect" absorption of infrared light. The impedance is theoretically calculated in the single-resonance approximation, and the responsible resonance is identified as a short-range surface plasmon. The spectral position of the absorption peak (which is as high as 95%) is experimentally shown to be controlled by the metamaterial's dimensions. The persistence of "perfect" absorption with variable metamaterial parameters is theoretically explained. The wide-angle nature of the absorber can be utilized for sub-diffraction-scale infrared pixels exhibiting spectrally selective absorption/emissivity.
Note: A new angle-resolved proton energy spectrometer
Zheng, Y.; Su, L. N.; Liu, M.; Liu, B. C.; Shen, Z. W.; Fan, H. T.; Li, Y. T.; Chen, L. M.; Lu, X.; Ma, J. L.; Wang, W. M.; Wang, Z. H.; Wei, Z. Y. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, J. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory for Laser Plasmas (MoE) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)
2013-09-15
In typical laser-driven proton acceleration experiments Thomson parabola proton spectrometers are used to measure the proton spectra with very small acceptance angle in specific directions. Stacks composed of CR-39 nuclear track detectors, imaging plates, or radiochromic films are used to measure the angular distributions of the proton beams, respectively. In this paper, a new proton spectrometer, which can measure the spectra and angular distributions simultaneously, has been designed. Proton acceleration experiments performed on the Xtreme light III laser system demonstrates that the spectrometer can give angle-resolved spectra with a large acceptance angle. This will be conductive to revealing the acceleration mechanisms, optimization, and applications of laser-driven proton beams.
Interstellar Refractive Scintillation and Intraday Polarization Angle Swings
Shan-Jie Qian; Xi-Zhen Zhang; A. Kraus
2005-01-01
Intraday polarization angle swings of ～180° observed in two sources (QSO 0917+624 and QSO 1150+812) are discussed in the framework of refractive interstellar scintillation by a continuous interstellar medium. Model-fits to the I-,Q- and U- light curves were made for both sources. It is shown that for the case of 0917+624 both the intraday intensity variations and the polarization angle swing of ～180° could be explained consistently in terms of a four-component model, which comprises one steady and two scintillating polarized components and one further non-polarized scintillating component. The polarization angle swing of ～180° observed in 1150+812, which occurred when the polarized flux density was almost constant, could not be explained in terms of refractive scintillation by a continuous medium and might be due to other mechanisms (e.g., scintillation by interstellar clouds).