bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptive and Nonlinear Fuzzy Force Control Techniques Applied to Robots Operating in Uncertain Environments
Authors: Burn K. , Short M. , Bicker R. 
Published: July 2003

AbstractFor robots to perform many complex tasks there is a need for robust and stable force control. Linear, fixed‐gain controllers can only provide adequate performance when they are tuned to specific task requirements, but if the environmental stiffness at the robot/task interface is unknown and varies significantly, performance is degraded. This paper describes the design of two nonlinear, fuzzy force controllers, developed primarily using analytical methods, which overcome the problems of conventional control. Using simulation and an experimental robot, they are shown to perform well over a wide range of stiffness and both a quantitative and qualitative assessment of their performance compared with conventional force control is presented. © 2003 Wiley Periodicals, Inc.
A Linear Algebraic Procedure in Obtaining Reciprocal Screw Systems
Authors: Dai Jian S. , Jones John Rees 
Published: July 2003

AbstractThis paper presents a linear algebraic procedure in obtaining (6−n) reciprocal screws from an n‐screw system of a robotic manipulator. The procedure starts by formulating the reciprocal relationship between a screw system and its reciprocal screw system in matrix form, and augmenting the screw matrix which is assembled with n screws in the screw system. Vectors of cofactors of the augmented row are then produced and the partitioning of the screw matrix is implemented to generate each of the (6−n) reciprocal screws. The theory developed in this paper provides a novel and simple procedure to obtain reciprocal screws from any screw system. The paper illustrates applications to cases with different screw systems. © 2003 Wiley Periodicals, Inc.
Review: Don't Cross‐Thread the Screw!*
Authors: Hunt Kenneth H. 
Published: July 2003

AbstractThe screw is a geometrical element. As Sir Robert Ball stated a century or more ago, the screw joins the company of point, plane, and line. In mechanics, especially instantaneous kinematics and statics of rigid bodies, angular and translational velocity of a body combine as a twist on a screw; precisely analogously a force and a couple combine as awrench on a screw. In three dimensions screw theory provides essential and simple insight into the behavior of systems of jointed bodies. And screw theory can also play a leading role in the systematic selection of suitable geometrical patterns that should relate to such jointed systems. Yet the mechanics of robots—the prime example today of systems of jointed bodies—has developed with little respect for the screw, even at the most elementary level. Here I focus mainly on robot performance, the study of which has, to an excessive extent, been proceeding blindly in territory where there is an abundance of screws and systems of screws, all, as it were, shouting to be taken on board to show the way. Failure to recognize the screw, and an unwillingness to use it properly, has led to the screw's being violently abused—“cross‐threaded.” There are far too many examples of “cross‐threading” that have, regrettably, appeared in recent years in several well‐known journals. Offenses have been perpetrated and yet left unchallenged. Here I try to remove any mystery that some may see surrounding, and even concealing, the screw. I then venture to deal critically with a small selection of the many instances of cross‐threading. However, this symposium has as a main objective the celebration of a Centenary. So it betokens an element of light‐heartedness that I resort to at times within the pages that follow. © 2003 Wiley Periodicals, Inc.
Describing three‐dimensional cervical spine movement in a diseased and a non‐diseased group using multilevel modelling
Authors: Jordan K. , Jones P. W. , Dziedzic K. 
Published: July 2003

AbstractClinicians often request patients to perform movements of joints as an aid to assessment and diagnosis of many diseases. However, patients may perform abnormal secondary movements where their primary movement is limited. A new measuring system, the FASTRAK, has the potential to measure movement in three dimensions, and to measure movements of the body away from the primary movement. This paper explores the use of multilevel modelling to describe the patterns of movement where subjects are measured on several occasions for both a non‐diseased group and for a group of subjects suffering from ankylosing spondylitis. Three‐level multilevel models are described with level 3 being the subjects, level 2 being the measurement occasions (up to three) and level 1 being the measurements (three) on each occasion. The models highlight which are the most important secondary movements during the primary movement and show clinically interpretable patterns of movement that can highlight differences between diseased and non‐diseased groups. Copyright © 2003 John Wiley & Sons, Ltd.
Applying the right statistics: analyses of measurement studies
Authors: Bland J. M. , Altman D. G. 
Published: July 2003

AbstractThe study of measurement error, observer variation and agreement between different methods of measurement are frequent topics in the imaging literature. We describe the problems of some applications of correlation and regression methods to these studies, using recent examples from this literature. We use a simulated example to show how these problems and misinterpretations arise. We describe the 95% limits of agreement approach and a similar, appropriate, regression technique. We discuss the difference vs. mean plot, and the pitfalls of plotting difference against one variable only. We stress that these are questions of estimation, not significance tests, and show how confidence intervals can be found for these estimates. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Maternal anxiety and fetal behavior at 15 weeks' gestation
Authors: Bartha J. L. , Martinez‐Del‐Fresno P. , Romero‐Carmona R. , Hunter A. , Comino‐Delgado R. 
Published: July 2003

AbstractObjectiveTo analyze the relationship between maternal anxiety and fetal behavior at 15 weeks' gestation.MethodsTwenty women in two groups were studied: 10 women underwent amniocentesis and 10 controls did not. Maternal anxiety was evaluated using the State Trait Anxiety Inventory questionnaire. Maternal plasma catecholamines (noradrenaline, adrenaline, dopamine) and maternal serum adrenocorticotropic hormone, cortisol, glucose, insulin, triiodothyronine, thyroxine and thyroid‐stimulating hormone were measured. Catecholamines were also measured in the amniotic fluid of women undergoing amniocentesis. Compiled actograms of 40‐min observations were done using ultrasonography.ResultsMaternal state‐anxiety was significantly increased in the amniocentesis group. Except for fetal hiccups (r = 0.49, P = 0.03) there was no significant correlation between maternal anxiety and any of the other studied fetal movements. Maternal glucose was significantly correlated with hiccups (r = −0.59, P = 0.01), isolated leg movements (r = −0.52, P = 0.03), startles (r = −0.47, P = 0.04) and the total of the studied movements (r = −0.47, P = 0.04). Amniotic fluid catecholamines were significantly correlated with hand–face contact (r = 0.71, P = 0.02 for adrenaline), startles (r = 0.75, P = 0.01 for noradrenaline and r = 0.64, P = 0.04 for dopamine) and general movements (r = 0.89, P = 0.001 for noradrenaline).ConclusionsThis study does not support a relationship between maternal anxiety and fetal behavior in early pregnancy. Maternal glucose and plasma catecholamines could be related to fetal movements at 15 weeks' gestation. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Estimation of fetal urinary bladder volume using the sum‐of‐cylinders method vs. the ellipsoid formula
Authors: Fägerquist M. , Fägerquist U. , Odén A. , Blomberg S. G. 
Published: July 2003

AbstractObjectivesA changing hourly fetal urine production rate (HFUPR) has been demonstrated when fetuses are subjected to hypoxia, which is of clinical interest. Conventionally, calculations of the HFUPR have been based on repeated two‐dimensional ultrasound bladder images during the filling phase and the formula for ellipsoids. However, the bladder shape changes from the ellipsoidal to super‐ellipsoidal during filling and the volume could be underestimated. In this study the sum‐of‐cylinders method was used, a method which does not depend on the longitudinal bladder shape being an ellipse.MethodsThe volumes from 102 urinary bladder images from 34 fetuses (three per fetus) were assessed using the sum‐of‐cylinders method. These results were compared with the corresponding findings when using the ellipsoid formula on the identical material of bladder images in a previous study.ResultsWhen using the sum‐of‐cylinders method vs. the ellipsoid formula, the mean volume difference was +1.6 mL. Applying the sum‐of‐cylinders method for bladder volumes of 5–40 mL resulted in standard deviations of 8.8–3.5% vs. 12.9–5.5% when using the ellipsoid formula. No deviation was found when using the sum‐of‐cylinders method vs. a known volume formula for cylinders, which simulated super‐ellipsoids on the computer screen.ConclusionsVolume calculation by the sum‐of‐cylinders method is independent of the longitudinal bladder shape when it comes to producing accurate estimations. This method demonstrated a systematically larger volume compared with the ellipsoid formula. The sum‐of‐cylinders method is therefore preferable for volume estimations of the fetal urinary bladder. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Uterine contractions increase fetal heart preload
Authors: Takahashi Y. , Iwagaki S. , Nakagawa Y. , Kawabata I. , Tamaya T. 
Published: July 2003

AbstractObjectiveThe preload index (PLI) has been shown to increase in the recipient fetus of twin–twin transfusion syndrome in the presence of uterine contractions. The objective of this study was to determine whether there are changes in PLI in the presence of uterine contractions in normal fetuses.MethodsInferior vena cava blood flow was measured using Doppler sonography in 45 normal fetuses at 18–41 weeks' gestation in the presence of uterine contractions and during quiescence and the PLI was compared between groups.ResultsThere was a highly significant difference (P < 0.0001) between the mean ± SD PLI in fetuses in the absence (0.235 ± 0.07) and in the presence (0.534 ± 0.183) of uterine contractions.ConclusionUterine contractions appear to increase fetal preload conditions in normal pregnancy. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
A histological and radiological investigation of the nasal bone in fetuses with Down syndrome
Authors: Tuxen A. , Keeling J. W. , Reintoft I. , Fischer Hansen B. , Nolting D. , Kjær I. 
Published: July 2003

AbstractObjectivesPrevious studies of nasal bone development in Down syndrome have used radiographs or ultrasound for the detection of nasal bone length or nasal bone absence. The aim of this study was to investigate the presence and size of the nasal bones in postmortem Down syndrome fetuses by means of radiographs and histological examination.MethodsThirty‐three aborted human fetuses (gestational age 14–25 weeks) with Down syndrome were included. A mid‐sagittal tissue block was excised from the skull base to the foramen magnum and along the lateral aspect of the spine. Radiographs of the tissue block were taken in lateral, frontal and axial projections. The length of the nasal bone was measured. The tissue blocks were cut in serial sections and stained. The crown–rump length (CRL), foot length (FL) and number of ossified bones in the hand and foot (CNO) were recorded.ResultsA total of 8/33 fetuses had bilateral nasal bone absence and two had unilateral absence. In fetuses with radiographically diagnosed nasal bone absence, no nasal bone could be found histologically. The majority of the Down syndrome fetuses had CRL, FL and CNO values within the range of those for normal age‐matched fetuses. Nasal bone length was normal or reduced.ConclusionsAbsence of the nasal bone was registered by postmortem examination in one‐third of fetuses with Down syndrome. In some fetuses this could be a result of delayed maturation associated with Down syndrome. The phenotypic differences in nasal bone appearance may reflect genotypic differences in the Down syndrome group. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of femur–fibula–ulna complex by ultrasound examination at 20 weeks of gestation
Authors: Geipel A. , Berg C. , Germer U. , Krokowski M. , Smrcek J. , Gembruch U. 
Published: July 2003

AbstractWe describe the prenatal sonographic diagnosis of femur–fibula–ulna complex at 20 weeks of gestation. On targeted ultrasound examination, a severe malformation of the lower limbs was observed. Further sonographic exploration demonstrated bilateral asymmetrical femoral hypoplasia, hypoplasia of both tibiae, bilateral aplasia of the fibulae and oligosyndactyly of the right hand with absence of the 4th and 5th rays. The prenatal sonographic features and differential diagnosis are discussed. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Acoustic streaming: a new technique for assessing adnexal cysts
Authors: Edwards A. , Clarke L. , Piessens S. , Graham E. , Shekleton P. 
Published: July 2003

AbstractObjectivesTo determine whether acoustic streaming has clinical value in the differentiation between various ovarian and adnexal cysts.MethodsWe assessed 29 adnexal cysts, for which pathological diagnosis was available, for the presence of acoustic streaming during B‐mode and color sonographic evaluation.ResultsAcoustic streaming was detected in 15 (52%) of the cysts. The most common cyst, endometrioma (n = 7), did not exhibit acoustic streaming in any case, while of the remaining 22 cysts, 15 exhibited acoustic streaming (P = 0.0017). Dermoid cysts exhibited acoustic streaming in two of six (33%) cases. In addition acoustic streaming was noted in two of two (100%) hemorrhagic cysts, eight of ten (80%) cystadenomas, two of three (67%) malignant cysts and in the one abscess.ConclusionsAcoustic streaming is the first sonographic feature that may be able to completely exclude endometrioma as a possible diagnosis for an adnexal cyst. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Reliability and validity of two methods of three‐dimensional cervical volume measurement
Authors: Farrell T. , Cairns M. , Leslie J. 
Published: July 2003

AbstractObjectivesTo determine if cervical length obtained with three‐dimensional ultrasound correlated with the ‘true cervical volume’ and to evaluate the reliability and validity of transabdominal and transvaginal three‐dimensional cervical volume measurement.MethodsThis was a prospective observational study. Three‐dimensional cervical volume measurements were made prior to hysterectomy in 28 women. Following hysterectomy the amputated cervical volume was calculated using water displacement. For the assessment of intra‐ and interobserver reliability, the intraclass correlation coefficient (ICC) was used. The index of concordance between the sonographic cervical volumes and those obtained by the reference standard (true cervical volume) was assessed with the limits of agreement method and the ICC.ResultsTransabdominal cervical length and transvaginal cervical length correlated moderately with actual cervical volume; correlation coefficients were 0.64 and 0.57 (P < 0.05), respectively. Intraobserver reliability for both transabdominal and transvaginal cervical volume assessment was good (> 0.75). Interobserver reliability for transvaginal cervical volumes was similarly good (ICC = 0.90). However, for transabdominal measurements the interobserver reliability was poor (ICC = 0.51). The validity of both methods of three‐dimensional volume assessment was poor (ICC < 0.75). This was reflected in the wide limits of agreement, which ranged from approximately − 25 mL to + 30 mL.ConclusionThe reliability and validity of three‐dimensional cervical volume measurement are poor. Clinical introduction of cervical volume measurement should be avoided at this time. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
The nasal bone in fetuses with trisomy 21: sonographic versus pathomorphological findings
Authors: Minderer S. , Gloning K. P. , Henrich W. , Stöger H. 
Published: July 2003

AbstractObjectiveTo compare the sonographic findings of the nasal bone in fetuses with trisomy 21 with pathomorphological findings to determine whether the bone is truly absent.MethodsSeventeen first‐trimester fetuses with trisomy 21 were identified; the median gestational age was 12 weeks (range, 11–14) and the median maternal age was 38 (range, 27–47) years. Transabdominal ultrasound examination, preceding transabdominal chorionic villus sampling (TA‐CVS) for karyotyping, included assessment of the fetal nose. The nasal bone was determined to be ‘hypoplastic’ or ‘absent’ and its length was measured. All pregnancies underwent termination after diagnosis. Serial sagittal sectioning with hematoxylin and eosin‐staining of formalin fixed tissue was performed.ResultsOf the 17 cases, the nasal bone was sonographically evident, but with severe hypoplasia in 10 cases, absent in six, and in the remaining case it was not able to be assessed due to fetal position. Histomorphologically, in 16 cases a nasal bone was present, detectable by the evidence of an ossification center, and in one case the ossification structure was not clearly visualized. Retrospective review of ultrasound images could identify nasal bones in five of the six cases in which they were initially reported as being absent on ultrasound examination. These were visible, but less distinct and had decreased echogenicity, hence misinterpretation led to the false finding of an absent nasal bone when it was in fact present but hypoplastic.ConclusionSonographic assessment of the fetal nasal bone should not distinguish between ‘present’ and ‘absent’, but instead between ‘normal’ and ‘hypoplastic’. For reproducible results it is necessary to standardize the sonographic examination. The sonographic landmarks of the fetal nose are: the nasal bone, the skin above and the cartilaginous tip of the nose. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Sonographic diagnosis of vesicouterine fistula
Authors: Park O.‐R. , Kim T.‐S. , Kim H.‐J. 
Published: July 2003

AbstractVesicouterine fistula is one of the least common types of urogenital fistula, accounting for only 1–4% of all cases. We report a case of vesicouterine fistula after vacuum delivery in a woman with a history of a previous Cesarean section. The 29‐year‐old woman was hospitalized due to continuous serosanguinous vaginal leakage and hematuria. Transvaginal sonography demonstrated the presence of a fistulous tract between the uterus and the bladder. Cystoscopy demonstrated a small opening in the posterior bladder wall and a cystogram revealed a fistulous tract between the posterior portion of the bladder and the uterine cavity. Since the patient could not tolerate her symptoms, we decided to close the fistulous tract surgically. The fistulous tract was excised and the bladder and uterus were closed primarily. The bladder was drained with a Foley catheter for 12 days and subsequent follow‐up of the patient has demonstrated urinary continence. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Revisiting first‐trimester fetal biometry
Authors: Salomon L. J. , Bernard J. P. , Duyme M. , Dorion A. , Ville Y. 
Published: July 2003

AbstractIntroductionAlthough advances in ultrasound have facilitated the diagnosis of fetal abnormalities in the first trimester, fetal biometry at this stage of pregnancy remains underused in prenatal diagnosis. We hypothesized that charts which directly correlate measurements to crown–rump length (CRL) could be more accurate than those based on gestational age (GA) derived from CRL measurement. The aim of this study was to construct CRL‐based biometric charts.MethodsMeasurements of biparietal diameter (BPD), head circumference (HC) and abdominal circumference (AC) were prospectively collected from 939 normal singleton fetuses. Charts and predictive equations were constructed from data obtained from pregnancies in which the CRL was between 45 and 84 mm and for which the outcome was normal.ResultsMeasurements of BPD, HC and AC from 880 fetuses who met the criteria were correlated with CRL and used to construct charts and predictive equations. The standard error of estimates using CRL was significantly lower than that using GA in all cases.DiscussionFirst‐trimester growth charts and predictive equations based on CRL instead of GA are more accurate. They might have a role in quality control of first‐trimester ultrasound examination and may help in the diagnosis of fetal conditions that involve early growth abnormalities. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Pre‐induction sonographic measurement of cervical length in prolonged pregnancy: the effect of parity in the prediction of induction‐to‐delivery interval
Authors: Rane S. M. , Pandis G. K. , Guirgis R. R. , Higgins B. , Nicolaides K. H. 
Published: July 2003

AbstractObjectiveTo examine the effect of parity on the relationship between pre‐induction cervical length and the induction‐to‐delivery interval and rate of vaginal delivery within 24 h in women undergoing induction of labor for prolonged pregnancy.MethodsIn 382 singleton pregnancies, induction of labor was carried out at 41 + 3 to 42 + 1 weeks of gestation. The cervical length was measured by transvaginal sonography before induction. Univariate analyses were performed by constructing Kaplan–Meier survival curves for the induction‐to‐delivery interval for various subgroups, and comparing these using log rank tests. Multivariate analyses were performed using the Cox proportional hazards model and multiple linear regression.ResultsSuccessful vaginal delivery within 24 h of induction occurred in 67% of the women and the pre‐induction cervical length was significantly associated with the induction‐to‐delivery interval and the rate of vaginal delivery within 24 h. Sonographically measured cervical length was better than the Bishop score or cervical length by vaginal examination in predicting the outcome of induction. Parity provided a significant independent contribution, in addition to pre‐induction cervical length, in the prediction of the outcome of labor. Thus, in multiparae the incidence of successful vaginal delivery within 24 h of induction was about 30% higher than in nulliparae. For the same cervical length, the induction‐to‐delivery interval in multiparae was 37% lower than in nulliparae.ConclusionIn women undergoing induction of labor for prolonged pregnancy, cervical length and parity provide independent prediction of induction‐to‐delivery interval and the likelihood of vaginal delivery within 24 h of induction. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.