bluuebunny/crossref_metadata_2025_split huggingface dataset:
A batch‐type time‐true ATM‐network simulator—design for parallel processing
Authors: Logothetis Michael , Liotopoulos Fotios 
Published: October 2002

AbstractThis paper presents a new type of network simulator for simulating the call‐level operations of telecom networks and especially ATM networks. The simulator is a pure time‐true type as opposed to a call‐by‐call type simulator. It is also characterized as a batch‐type simulator. The entire simulation duration is divided into short time intervals of equal duration,t. Duringt, a batch processing of call origination or termination events is executed and the time‐points of these events are sorted. The number of sorting executions is drastically reduced compared to a call‐by‐call simulator, resulting in considerable timesaving. The proposed data structures of the simulator can be implemented by a general‐purpose programming language and are well fitted to parallel processing techniques for implementation on parallel computers, for further savings of execution time. We have first implemented the simulator in a sequential computer and then we have applied parallelization techniques to achieve its implementation on a parallel computer. In order to simplify the parallelization procedure, we dissociate the core simulation from the built‐in call‐level functions (e.g. bandwidth control or dynamic routing) of the network. The key point for a parallel implementation is to organize data by virtual paths (VPs) and distribute them among processors, which all execute the same set of instructions on this data. The performance of the proposed batch‐type, time‐true, ATM‐network simulator is compared with that of a call‐by‐call simulator to reveal its superiority in terms of sequential execution time (when both simulators run on conventional computers). Finally, a measure of the accuracy of the simulation results is given. Copyright © 2002 John Wiley & Sons, Ltd.
Association between first trimester absence of fetal nasal bone on ultrasound and Down syndrome
Authors: Otaño L. , Aiello H. , Igarzábal L. , Matayoshi T. , Gadow E.C. 
Published: October 2002

AbstractObjectivesTo evaluate the association between absence of nasal bone on ultrasound and Down syndrome in fetuses at 11–14 weeks of pregnancy.MethodsOne hundred and ninety‐four consecutive fetuses from singleton pregnancies undergoing chorionic villi sampling (CVS) were evaluated by transabdominal ultrasound. A sagittal view of the fetal face was obtained and the absence or presence of nasal bone was recorded and correlated with the fetal karyotype.ResultsA successful view of the fetal profile was possible in 183 of 194 (94%) fetuses. The nasal bone was absent in three of five fetuses with Down syndrome, and in one of 175 (0.6%) chromosomally normal fetuses.ConclusionAbsence of nasal bone by first trimester ultrasound was significantly associated with Down syndrome. When a proper view of the fetal face was obtained, the nasal bone was visible in more than 99% of karyotypically normal fetuses. Copyright © 2002 John Wiley & Sons, Ltd.
Agreement between predicted risk and prevalence of Down syndrome in first trimester nuchal translucency screening
Authors: Prefumo Federico , Thilaganathan Basky 
Published: October 2002

AbstractThe agreement between predicted risks of Down syndrome and observed prevalence was investigated in a population of 11 847 singleton pregnancies screened by first trimester nuchal translucency at a single institution. Twenty‐seven cases of Down syndrome were observed; 20 were detected prenatally by nuchal translucency and maternal age screening, three by other means and four postnatally. The screened women were grouped according to their predicted risk of having an affected pregnancy, and this was compared with the observed prevalence. A significant correlation between predicted and observed prevalences was noted, thus demonstrating that risk estimates for Down syndrome based on first trimester nuchal translucency screening are accurate. Copyright © 2002 John Wiley & Sons, Ltd.
Role of the CdS buffer layer as an active optical element in Cu(In,Ga)Se2thin‐film solar cells
Authors: Orgassa Kay , Rau Uwe , Nguyen Quang , Werner Schock Hans , Werner Jürgen H. 
Published: October 2002

AbstractZnO/CdS/Cu(In,Ga)Se2(CIGS) thin‐film heterojunction solar cells with CdS buffer layers of thicknesses between 0 and 85 nm are characterized by current–voltage, quantum efficiency, and optical reflection measurements. We investigate the correlation between the short‐circuit current density and the CdS layer thickness, focusing on the counteracting effects of light absorption and reduced optical reflection induced by the CdS layer. Both effects almost compensate each other for CdS layer thicknesses between 0 and 40 nm. Thus, an optimization of the short‐circuit current density is not achieved by omitting the CdS layer, but rather by replacing the CdS buffer with an alternative buffer material with higher bandgap energy and optical constants similar to those of CdS. Copyright © 2002 John Wiley & Sons, Ltd.
Composite beams and floor systems fully integrated with building services
Authors: Chung K F 
Published: October 2002

AbstractThis paper reviews the latest design developments in composite beams and floor systems fully integrated with building services. A number of composite floor systems developed specifically for integration of building services in commercial buildings are presented, namely, fabricated beams with tapered webs, haunched beams, trusses, stub girders, parallel beam grillage systems and slim floor systems.Furthermore, the design and construction of steel and composite beams with large web openings is also discussed. Recent design developments for steel beams with web openings of various shapes and composite beams with large web openings to Eurocode 4 are also reported.
Genetic Screening for MEN1 Mutations in Families Presenting with Familial Primary Hyperparathyroidism
Authors: Perrier Nancy D. , Villablanca Andrea , Larsson Catharina , Wong Mariwil , Ituarte Philip , Teh Bin Tean , Clark Orlo H. 
Published: October 2002

A large number of families with familial isolated hyperparathyroidism (FIHP) have been reported. We wanted to determine if some of these families represent early manifestations of full‐blown syndromes such as multiple endocrine neoplasia type 1
(MEN‐1), as early identification may alter surgical and medical management. Four small families with a family history of hyperparathyroidism without clear‐cut MEN‐1 features were screened for a MEN1 mutation. The 10 exons of the MEN1 gene were amplified and analyzed by single‐strand conformation analysis
(SSCA). Abnormal SSCA shifts were then sequenced using an automated sequencer. Two germline mutations were found: R527X and P277H. The former was detected in three members of a family consisting of two children and a mother. At the time of testing the youngest son was normocalcemic and clinically normal but subsequently developed hyperparathyroidism (HPT). Since the initial testing, the family has been confirmed to be a MEN‐1 family as the mother has developed abdominal pain and an elevated serum pancreatic polypeptide and the younger brother an anterior pituitary tumor and recurrent HPT. The latter P277H mutation was identified in two of three members tested from another family. Manifestations of MEN‐1 syndrome have also developed. The father now has developed diarrhea and elevated serum gastrin; and the daughter has developed recurrent HPT. Genetic screening of families who clinically have FIHP is important and may influence the type of medical and surgical treatment and follow‐up, as some have MEN‐1 syndrome. Long‐term screening for MEN syndromes should be included in this set of patients. Positive screening may predict disease and allow early detection and appropriate treatment before initiation of symptoms.
Antepartum prophylactic transabdominal amnioinfusion in preterm pregnancies complicated by oligohydramnios
Authors: Turhan N.Ö , Atacan N 
Published: October 2002

AbstractObjective: To assess the role of amnioinfusion in preterm pregnancies with oligohydramnios. Method: 29 women between 23 and 35 weeks’ gestation were enrolled in the study. Transabdominal amnioinfusion was performed in 15 pregnancies, 14 patients were managed expectantly. The latency period and perinatal outcome of both groups were compared using the Mann–Whitney U‐test and χ2‐test. Result: The amniotic fluid index significantly increased from a median value of 6 to 11 cm (P<0.0001) in the amnioinfusion group after amnioinfusion. The latency period of the amnioinfusion group was significantly longer (median 15 vs. 8 days P<0.05). Gestational week of the amnioinfusion group was earlier on admission (median 30.6 vs. 33.4 weeks, P=0.01) but at delivery this diversity disappeared (median 33.4 vs. 34.8 weeks, P=0.10). The perinatal outcomes of the two groups were similar. Conclusion: Transabdominal amnioinfusion prolongs the latency period and improves perinatal outcome in preterm pregnancies complicated by oligohydramnios.
Toward a theory of project interdependencies in high tech R&D environments
Authors: Verma Devesh , Sinha Kingshuk K 
Published: October 2002

AbstractIn today’s intensely competitive market place, high technology firms are challenged with the task of managing multiple‐concurrent research and development (R&D) projects with constrained resources. As success in the business world depends on the ability to do more with less, it is important for these high technology firms to understand why certain projects consume less monetary resources but still achieve superior product development outcomes. To address this question, we develop a theoretical framework for understanding the interdependencies between projects and their relationship to project performance in a multiple‐concurrent R&D environment. The framework is developed through multiple‐case studies of projects undertaken by a Fortune 500 high technology manufacturing firm. The seven projects that comprised the sample for the multiple‐case study were chosen from a larger portfolio of projects belonging to a technology group at the firm’s corporate R&D center. The choice of the seven projects was guided by a data envelopment analysis (DEA)‐based project performance metric, also proposed in this paper.
Mechanobiology of initial pseudarthrosis formation with oblique fractures
Authors: Loboa Elizabeth G. , Beaupré Gary S. , Carter Dennis R. 
Published: October 2002

AbstractMechanical stresses play an important role in regulating tissue differentiation in a variety of contexts during skeletal development and regeneration. It has been shown that some intermittent loading at a fracture site can accelerate secondary fracture healing. However, it has not been shown how the stress and strain histories resulting from mechanical loading of a fracture might, in some cases, inhibit normal fracture healing and induce pseudarthrosis formation. In this study, finite element analysis is used to calculate hydrostatic stress and maximum principal tensile strain patterns in regenerating tissue around the site of an oblique fracture. Using a mechanobiologic view on tissue differentiation, we compared calculated stress and strain patterns within the fracture callus to the histomorphology of a typical oblique pseudarthrosis. Tissue differentiation predictions were consistent with the characteristic histomorphology of oblique pseudarthrosis: in the interfragmentary gap, tensile strains led to “cleavage” of the callus; at the ends of both fracture fragments, hydrostatic pressure and tensile strain caused fibrocartilage formation; and, at discrete locations of the periosteum at the oblique fracture ends, mild hydrostatic tension caused bone formation. We also found that discrete regions of high hydrostatic pressure correlated with locations of periosteal bone resorption. When previous findings with distraction osteogenesis are considered with these observations, it appears that low levels of hydrostatic pressure may be conducive to periosteal cartilage formation but high hydrostatic pressure may induce periosteal bone resorption during bone healing. We concluded that tissue differentiation in pseudarthrosis formation is consistent with concepts previously presented for understanding fracture healing, distraction osteogenesis, and joint formation. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The role of collagen in determining bone mechanical properties
Authors: Wang Xiaodu , Bank Ruud A. , Tekoppele Johan M. , Agrawal C. Mauli 
Published: October 2002

AbstractThe hypothesis of this study was that collagen denaturation would lead to a significant decrease in the toughness of bone, but has little effect on the stiffness of bone. Using a heating model, effects of collagen denaturation on the biomechanical properties of human cadaveric bone were examined. Prior to testing, bone specimens were heat treated at varied temperatures (37–200°C) to induce different degrees of collagen denaturation. Collagen denaturation and mechanical properties of bone were determined using a selective digestion technique and three‐point bending tests, respectively. The densities and weight fractions of the mineral and organic phases in bone also were determined. A repeated measures analysis of variance showed that heating had a significant effect on the biomechanical integrity of bone, corresponding to the degree of collagen denaturation. The results of this study indicate that the toughness and strength of bone decreases significantly with increasing collagen denaturation, whereas the elastic modulus of bone is almost constant irrespective of collagen denaturation. These results suggest that the collagen network plays an important role in the toughness of bone, but has little effect on the stiffness of bone, thereby supporting the hypothesis of this study. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Mechanisms of chondrocyte adhesion to cartilage: role of β1‐integrins, CD44, and annexin V
Authors: Kurtis Melissa S. , Tu Buu P. , Gaya Omar A. , Mollenhauer JÜRgen , Knudson Warren , Loeser Richard F. , Knudson Cheryl B. , Sah Robert L. 
Published: October 2002

AbstractThe initial adhesion of transplanted chondrocytes to surrounding host cartilage may be important in the repair of articular defects. Adhesion may position cells to secrete molecules that fill the defect and integrate repair tissue with host tissue. While chondrocytes are known to become increasingly adherent to cartilage with time, the molecular basis for this is unknown. The objective of this study was to investigate the role of β1‐integrin, CD44, and annexin V receptors in chondrocyte adhesion to cartilage. Chondrocytes were cultured in high density monolayer, released with trypsin, and allowed to recover in suspension for 2 h at 37°C. Under these conditions, flow cytometry analysis showed that chondrocytes expressed β1‐integrins, CD44, and annexin V. In a rapid screening assay to assess chondrocyte adhesion to cartilage, cell detachment decreased from 79% at 10 min following transplantation to 10% at 320 min. Treatment of cells with a monoclonal antibody to block β1‐integrins significantly increased chondrocyte detachment from cartilage compared to untreated controls. Similarly, results from a parallel‐plate shear flow adhesion assay showed that blocking β1‐integrins significantly increased chondrocyte detachment from cartilage compared to untreated controls at each level of applied shear (0–70 Pa). In both assays, treatment of cells with reagents that block CD44 (hyaluronan oligosaccharides or monoclonal Ab IM7) or annexin V (polyclonal Ab #8958) had no detectable effect on adhesion. With cartilage treated with chondroitinase ABC, blocking β1‐integrins also increased chondrocyte detachment, while blocking CD44 and annexin V also had no detectable effect. Under the conditions studied here, β1‐integrins appear to mediate chondrocyte adhesion to a cut cartilage surface. Delineation of the mechanisms of adhesion may have clinical implications by allowing cell manipulations or matrix treatments to enhance chondrocyte adhesion and retention at a defect site. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The effect of ovariectomy and ovarian steroid treatment on growth hormone and insulin‐like growth factor‐I levels in the rat femur
Authors: Suliman Isam A. , El‐Bakri Nahid K. , Adem Abdu , Mustafa Amged , Lindgren J Urban 
Published: October 2002

AbstractGrowth hormone (GH) and insulin‐like growth factor‐I (IGF‐I) are known to play an important role in bone metabolism. The regulation of plasma levels of GH and IGF‐I by ovarian steroids is well known, however, their effect on local GH and IGF‐I is still unclear. In this study, we investigated the effect of ovariectomy and ovarian steroid treatment on the femur GH and IGF‐I levels as well as on bone density in the rat. Nine month‐old rats were ovariectomized (OVX) or sham‐operated (SHAM) and 9 weeks after the surgery they were treated with daily s.c. injections of either 17β‐estradiol (OVX + E), progesterone (OVX + P), or vehicle (OVX + V) for another 10 weeks. GH and IGF‐I levels in the femur extracts were measured by specific radioimmunoassay (RIA). Ovariectomy decreased GH and had no effect on IGF‐I levels. Estradiol treatment increased femur GH and IGF‐I levels compared to SHAM rats. Progesterone restored GH and increased IGF‐I levels. Ovariectomy decreased, estrogen restored and progesterone partially restored femur bone density. Our results demonstrate that ovariectomy and ovarian steroids modulate the levels of GH and IGF‐I in the bone of aged OVX rats. However, these effects appear to be limited to supraphysiological concentrations of estradiol and progesterone. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
EMG activity of trunk muscles and torque output during isometric axial rotation exertion: a comparison between back pain patients and matched controls
Authors: Ng Joseph K.‐F. , Richardson Carolyn A. , Parnianpour Mohamad , Kippers Vaughan 
Published: October 2002

AbstractAbnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial torque output during isometric axial rotation at different exertion levels in back pain patients and matched controls. Twelve back pain patients and 12 matched controls performed isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions in a standing position. Surface EMG activity of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were measured. Results showed that there was a trend (P = 0.08) of higher flexion coupling torque during left axial rotation exertion in back pain patients. Higher activity for external oblique and lower activity for multifidus was shown during left axial rotation exertion in back pain group when compared to the control group. In right axial rotation, back pain patients exhibited lesser activity of rectus abdominis at higher levels of exertion when compared with matched controls. These findings demonstrated that decreased activation of one muscle may be compensated by overactivity in other muscles. The reduced levels of activity of the multifidus muscle during axial rotation exertion in back pain patients may indicate that spinal stability could be compromised. Future studies should consider these alternations in recruitment patterns in terms of spinal stability and internal loading. The findings also indicate the importance of training for coordination besides the strengthening of trunk muscles during rehabilitation process. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Stretch and interleukin‐1β induce matrix metalloproteinases in rabbit tendon cells in vitro
Authors: Archambault Joanne , Tsuzaki Mari , Herzog Walter , Banes Albert J. 
Published: October 2002

AbstractLittle is known about the factors that initiate and propagate tendon overuse injuries, but chronic inflammation and matrix destruction have been implicated. The purpose of this study was to evaluate the production of cyclooxygenase II (COX‐2) and matrix metalloproteinases (MMPs) by tendon cells exposed to cyclic strain and inflammatory cytokines in vitro. Rabbit Achilles tendon cells were subjected to a stretching protocol with 5% elongation at 0.33 Hz for 6 h, or treated with 1000 pM interleukin‐1β (IL‐1β), or exposed to IL‐1β and stretching together. Gene expression was evaluated by RT‐PCR and production of stromelysin was quantified with an ELISA. IL‐1β induced the expression of the collagenase‐1 and stromelysin‐1 genes. Production of stromelysin proenzyme by cells stimulated with IL‐1β was 17 times higher than production by control cells. Cells exposed to IL‐1β and stretching produced 20 times more stromelysin than control cells. Cells subjected to stretching alone did not produce more stromelysin than control cells. The synergistic effect of IL‐1β and stretching was observed at doses of IL‐1β ranging from 10 to 1000 pM. These data suggest that mechanical load and inflammatory cytokines can initiate a matrix destructive pathway in tendon that is more pronounced than with mechanical loading or inflammation alone. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Altered swelling behavior of femoral cartilage following joint immobilization in a canine model
Authors: Narmoneva Daria A. , Cheung Herman S. , Wang Jean Y. , Howell David S. , Setton Lori A. 
Published: October 2002

AbstractPeriods of reduced joint loading have been shown to induce changes in the biochemical composition, metabolism and mechanics of articular cartilage. In this study, changes in cartilage swelling behavior were studied following a 4‐week period of joint immobilization, using a recently developed osmotic loading technique [J. Biomech. 32 (1999) 401–408]. The magnitude and distribution of swelling strains were measured in cartilage–bone samples equilibrated in physiological and hypotonic saline, relative to a hypertonic reference NaCl solution. Physicochemical parameters (glycosaminoglycan fixed charge density and water volume fraction) were determined in site‐matched cartilage samples. The experimental data for swelling strains, fixed charge density and water volume fraction were used with a triphasic mechano‐chemical theory [J. Biomech. Eng. 113 (1991) 245–258] to determine the effect of joint immobilization on the tensile modulus of the cartilage solid matrix. Four weeks of immobilization resulted in a significant increase in the magnitude of swelling‐induced strains, and a significant decrease in fixed charge density in cartilage, as compared with the contralateral controls. Joint immobilization also resulted in decreases in values for the modulus of cartilage, as compared with the contralateral controls. Our results suggest that 4 weeks of joint immobilization had a significant effect on cartilage mechanical function that may be linked to collagen changes in the cartilage extracellular matrix. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.