bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved diffusion‐weighted single‐shot echo‐planar imaging (EPI) in stroke using sensitivity encoding (SENSE)
Authors: Bammer Roland , Keeling Stephen L. , Augustin Michael , Pruessmann Klaas P. , Wolf Roswitha , Stollberger Rudolf , Hartung Hans‐Peter , Fazekas Franz
Published: August 2002

Diffusion‐weighted single‐shot EPI (sshEPI) is one of the most important tools for the diagnostic assessment of stroke patients, but it suffers from well known artifacts. Therefore, sshEPI was combined with SENSitivity Encoding (SENSE) to further increase EPI's potential for stroke imaging. Eight healthy volunteers and a consecutive series of patients (N = 8) with suspected stroke were examined with diffusion‐weighted SENSE‐sshEPI using different reduction factors (1.0 ≤ R ≤ 3.0). Additionally, a high‐resolution diffusion‐weighted SENSE‐sshEPI scan was included. All examinations were diagnostic and of better quality than conventional sshEPI. No ghostings or aliasing artifacts were discernible, and EPI‐related image distortions were markedly diminished. Chemical shift artifacts and eddy current‐induced image warping were still present, although to a markedly smaller extent. Measured direction‐dependent diffusion‐coefficients and isotropic diffusion values were comparable to previous findings but showed less fluctuation. We have demonstrated the technical feasibility and clinical applicability of diffusion‐weighted SENSE‐sshEPI in patients with subacute stroke. Because of the faster k‐space traversal, this novel technique is able to reduce typical EPI artifacts and increase spatial resolution while simultaneously remaining insensitive to bulk motion. Magn Reson Med 46:548–554, 2001. © 2001 Wiley‐Liss, Inc.
T and T maps derived in vivo from the rat using longitudinally detected electron spin resonance phase imaging: Application to abdominal oxygen mapping
Authors: Panagiotelis Ioannis , Nicholson Ian , Foster Margaret A. , Hutchison James M.S.
Published: August 2002

A novel imaging modality is introduced which uses radiofrequency longitudinally detected electron spin resonance (RF‐LODESR). It is capable of providing qualitative and semiquantitative information on a variety of parameters reflecting physiological function, the most significant being tissue oxygenation. Effective spin‐lattice (T) and spin‐spin (T) electronic relaxation time maps of the abdomen of living 200‐g rats were generated after intravenous administration of a triarylmethyl free radical (TAM). These maps were used to evaluate oxygen distribution. Differences between the liver, kidneys, and bladder were noted. Conclusions were made regarding the distribution, perfusion, and excretion rate of the contrast medium. Ligature‐induced anoxia in the kidney was also visualized. LODESR involves transverse ESR irradiation with a modulated excitation, and observing oscillations in the spin magnetization parallel to the main magnetic field. The T and T maps were calculated from a set of LODESR signal phase images collected at different detection frequencies. Each phase image also provides qualitative information on tissue oxygen levels without any further processing. This method presents an alternative to the conventional transverse ESR linewidth‐based oximetry methods, particularly for animal whole‐body imaging applications. Magn Reson Med 46:1223–1232, 2001. © 2001 Wiley‐Liss, Inc.
Continuous myonuclear addition to single extraocular myofibers in uninjured adult rabbits
Authors: McLoon Linda K. , Wirtschafter Jonathan D.
Published: August 2002

Extraocular muscles (EOM) are unique among mammalian skeletal muscles in that they normally express molecules associated with muscle development and regeneration. In this study we show that satellite cells of EOM, unlike those of other skeletal muscles, continually divide in the normal, uninjured adult. Adult EOM contained activated satellite cells positive for the myogenic regulatory factor MyoD. EOM satellite cells did not require a prolonged activation period prior to onset of cell division and differentiation in vitro. EOM satellite cells incorporated bromodeoxyuridine (brdU), a marker for cell division, and with longer postlabeling survival, brdU‐labeled nuclei populated EOM myofibers. This was not seen with leg muscle. These findings suggest the possibility that continual division of satellite cells and fusion of their daughter myocytes with existing adult EOM myofibers contribute to the unique sparing or susceptibility of EOM to certain muscle diseases. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Digit distribution of proper digital nerve action potential
Authors: King John C. , Dumitru Daniel , Wertsch Jacqueline J.
Published: August 2002

Antidromic sensory nerve action potential testing is well characterized and commonly used to assess the sensory component of the upper limb median and ulnar nerves. The final terminal segments of these nerves are the proper digital nerves. Ring recording electrodes are commonly used to detect the proper digital nerves' antidromic responses. Attempts to record the separate contributions of individual digital nerves along the lateral aspects of each finger, using small surface electrodes, is shown to be unreliable for determining the integrity of a single terminal digital branch. We found between 50% to 77% of the stimulated terminal branch's response amplitude when recorded at electrodes positioned over the nonstimulated branch located 180° from the activated terminal branch. Detecting a single terminal nerve response was achieved by using the fourth digit and the second digit with one of the second digit's branches neurophysiologically blocked by local anesthetic. The volume‐conducted response from the opposite side of the finger resulted in this relatively large recorded response, which remains within the range of reference values precluding the simple use of antidromic techniques to assess injury to a single proper digital nerve. Techniques are proposed to avoid such pitfalls and to assess most accurately the desired response. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1489–1495, 2001
An analytical assessment on the impact of covers on the onset of air convection in mine wastes
Authors: Lu Ning
Published: August 2002

If a mine waste pile is left open, an active chemical reaction of oxidation is often found due to the commonly high content of pyritic materials. The oxidation of pyrites is an exothermic process and the released heat will promote the flow of fresh oxygen from the surrounding atmosphere into the waste dump. As a result, oxidation reaction will accelerate and temperature within the dump can increase to as high as 60°C above the ambient temperature. The oxidation process also releases sulphuric acid and hydrogen ions into ground water to cause water contamination. Low‐permeability covers such as clay liners have been recently proposed to abate the oxidation process in mine wastes. The effectiveness of using low‐permeability materials to cover mine wastes in order to suppress the pyrite oxidation is examined. By conducting the theoretical analysis of the onset of convective air flow within waste rocks, the conditions under which soil gas flow is significant are identified. By comparing the results with previous field measurements and theoretical analysis for the uncovered conditions, it is shown that low‐permeability covers can effectively suppress soil gas flow and slow down the pyrite oxidation process in mine wastes. Copyright © 2001 John Wiley & Sons, Ltd.
Neurological signs are common in patients with urodynamically verified “idiopathic” bladder overactivity
Authors: Ahlberg Jarl , Edlund Christer , Wikkelsö Carsten , Rosengren Lars , Fall Magnus
Published: August 2002

Overactive bladder dysfunction is an expression of defective neuromuscular control of the lower urinary tract. The causes and the way to classify this problem are currently under debate. In some patients the overactive bladder is one sign of a neurological disorder, in so called “idiopathic detrusor instability” the cause is less obvious. That an overactive bladder has a neurogenic cause is a reasonable hypothesis. We made a detailed neurological investigation in 45 patients with idiopathic overactive bladder. Cerebrospinal fluid (CSF) was examined and blood tests for vitamin B12and folic acid deficiency were checked, too. In 37 of the 45 patients (82%) pathological signs were observed in the neurological tests. The most common finding was central or peripheral paresis of the legs appearing in 24 patients (53%). Of the 45 patients, eight received a neurological diagnosis, definite or possible MS or dorsal column sensation neuropathy. The results of this study give an indication of the importance of the neurological examination and suggest that neuropathy might not be uncommon in patients with so‐called idiopathic detrusor instability. This also invites to reconsideration of the current classification. It is possible that a new classification based on a functional view could provide a better fundament in the search of etiologic and pathogenetic factors and also guide in the selection of the treatment most optimal for the individual patient. Neurourol. Urodynam. 21:65–70, 2002. © 2002 Wiley‐Liss, Inc.
Bayesian testing strategies for software with an operational profile
Authors: Özekici S. , Soyer R.
Published: August 2002

We consider a software reliability model where the failure rate of each fault depends on the specific operation performed. The software is tested in a given sequence of test cases for fixed durations of time to collect data on failure times. We present a Bayesian analysis of software failure data by treating the initial number of faults as a random variable. Our analysis relies on the Markov Chain Monte Carlo methods and is used for developing optimal testing strategies in an adaptive manner. Two different models involving individual and common faults are analyzed. We illustrate an implementation of our approach by using some simulated failure data. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:747–763, 2001
Proton T1 and T2 relaxation times of human brain metabolites at 3 Tesla
Authors: Mlynárik Vladimír , Gruber Stephan , Moser Ewald
Published: August 2002

Longitudinal and transverse relaxation times were measured for proton MRS signals from human brain metabolites at 3 T using a short‐echo STEAM protocol and a surface coil as a transmitter/receiver. Volumes of interest containing mostly grey or mostly white matter were selected in occipital lobes of healthy subjects and relaxation times for the following resonances were obtained: N‐acetylaspartate at 2.01 ppm (T1 and T2), glutamate at 2.35 ppm (T1), creatine at 3.03 and 3.92 ppm (T1 and T2), choline‐containing substances at 3.22 ppm (T1 and T2), myo‐inositol at 3.57 and 3.65 ppm (T1) and the overlapping signals of glutamate and glutamine at 3.75 ppm (T1). The T1 relaxation times obtained range from 0.97 to 1.47 s for grey matter and from 0.87 to 1.35 s for white matter. On the other hand, T2 relaxation times range from 116 to 247 ms and from 141 to 295 ms in grey and white matter, respectively. Generally, the T1 values measured at 3 T are close to the previously published data found at 1.5, 2 and 4.1 T. Also, the T2 values confirm the previously observed decrease in transverse relaxation times with increasing static magnetic field. The proton relaxation times obtained will allow improved sequence design and spectra quantitation at 3 T, currently tested for enhanced clinical applications. Copyright © 2001 John Wiley & Sons, Ltd.
On the traveling salesman problem restricted to inputs satisfying a relaxed triangle inequality
Authors: Andreae Thomas
Published: August 2002

For a finite set X, let c be a mapping which assigns to every two‐element subset {u, v} of X a nonnegative real number c(u, v), the cost of {u, v}. For τ ∈ ℝ, τ ≥ 1, we say that the pair (X, c) satisfies the τ‐inequality (“relaxed triangle inequality”) if c(u, v) ≤ τ(c(u, w) + c(w, v)) for each three‐element subset {u, v, w} of X. For fixed τ ≥ 1, we denote by Δτ TSP the Traveling Salesman Problem (TSP) restricted to inputs (X, c) satisfying the τ‐inequality. In a paper of the present author and H.‐J. Bandelt [SIAM J Discr Math 8 (1995), 1–16], a heuristic, called the T3‐algorithm, was proposed for the TSP and it was shown that this heuristic is an approximation algorithm for Δτ TSP with performance guarantee $c_{{approx}} {\le} ({{3}\over{2}}\tau^{2} + {{1}\over{2}}{\tau}){c}_{{min}}$. In the present paper, by means of appropriately refining the T3‐algorithm, an improved performance guarantee of factor τ2 + τ (instead of ${{3}\over{2}}\tau^{2} + {{1}\over{2}}\tau$) is established (which is best possible for certain refined versions of the T3‐algorithm). This settles a conjecture of Andreae and Bandelt. Also, related results are derived and examples are given which shed light on the original (unrefined) T3‐algorithm and the improved version presented here. © 2001 John Wiley & Sons, Inc.
A comparison of domain integral evaluation techniques for boundary element methods
Authors: Ingber Marc S. , Mammoli Andrea A. , Brown Mary J.
Published: August 2002

In many cases, boundary integral equations contain a domain integral. This can be evaluated by discretization of the domain into domain elements. Historically, this was seen as going against the spirit of boundary element methods, and several methods were developed to avoid this discretization, notably dual and multiple reciprocity methods and particular solution methods. These involved the representation of the interior function with a set of basis functions, generally of the radial type. In this study, meshless methods (dual reciprocity and particular solution) are compared to the direct domain integration methods. The domain integrals are evaluated using traditional methods and also with multipole acceleration. It is found that the direct integration always results in better accuracy, as well as smaller computation times. In addition, the multipole method further improves on the computation times, in particular where multiple evaluations of the integral are required, as when iterative solvers are used. The additional error produced by the multipole acceleration is negligible. Copyright © 2001 John Wiley & Sons, Ltd.
An objective finite element approximation of the kinematics of geometrically exact rods and its use in the formulation of an energy–momentum conserving scheme in dynamics
Authors: Romero I. , Armero F.
Published: August 2002

We present in this paper a new finite element formulation of geometrically exact rod models in the three‐dimensional dynamic elastic range. The proposed formulation leads to an objective (or frame‐indifferent under superposed rigid body motions) approximation of the strain measures of the rod involving finite rotations of the director frame, in contrast with some existing formulations. This goal is accomplished through a direct finite element interpolation of the director fields defining the motion of the rod's cross‐section. Furthermore, the proposed framework allows the development of time‐stepping algorithms that preserve the conservation laws of the underlying continuum Hamiltonian system. The conservation laws of linear and angular momenta are inherited by construction, leading to an improved approximation of the rod's dynamics. Several numerical simulations are presented illustrating these properties. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of nicotine on motor activity, passive avoidance and plus‐maze behavior in aged NMRI and C57BL mice
Authors: Redolat R. , Vicens P. , Carrasco M.C.
Published: August 2002

The aim of the present study is to evaluate the effects of nicotine (0.35 and 0.175 mg/kg) on locomotor activity, passive avoidance and plus maze behavior in aged mice of two strains (C57BL and NMRI). In a first experiment, aged mice of these strains were injected with nicotine or saline and immediately afterwards were put on the actimeter. Results showed that nicotine significantly decreased locomotor activity in C57 mice. In a second experiment, nicotine was administered before training and retention sessions of a passive avoidance task. Results indicated that 0.175 mg/kg nicotine significantly increased entry latency in aged NMRI mice but had no effects on C57 mice. In the last experiment, mice were injected with nicotine and 15 min later evaluated in the plus‐maze for 5 min. It was observed that in NMRI mice no measure was significantly affected by nicotine but in C57 mice this drug significantly reduced the number of total entries, number of entries in open arms and in the central area of the maze. It is concluded that in aged mice nicotine effects depend on the baseline behaviors of the strains evaluated.
Nonnested multigrid methods for linear problems
Authors: Bittencourt Marco L. , Douglas Craig C. , Feijóo Raúl A.
Published: August 2002

This article presents an application of nonnested and unstructured multigrid methods to linear elastic problems. A variational formulation for transfer operators and some multigrid strategies, including adaptive algorithms, are presented. Expressions for the performance evaluation of multigrid strategies and its comparison with direct and preconditioned conjugate gradient algorithms are also presented. A C++ implementation of the multigrid algorithms and the quadtree and octree data structures for transfer operators are discussed. Some two‐ and three‐dimensional elasticity examples are analyzed. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17:313–331, 2001
Psychometric evaluation of the personal lifestyle questionnaire for adolescents†
Authors: Mahon Noreen E. , Yarcheski Adela , Yarcheski Thomas J.
Published: August 2002

The purpose of this study was to provide evidence of validity for the Personal Lifestyle Questionnaire (PLQ), a measure of positive health practices, in a sample of 222 adolescents ages 15–21. Using a priori criteria, it was found that a two‐factor solution, resulting from a principal components analysis with an orthogonal rotation, best represented the factor structure of the PLQ for adolescents. Of the two factors, only Factor I demonstrated an acceptable coefficient alpha reliability; this factor was labeled General Health Practices. Evidence of construct validity for the total PLQ was provided by two statistically significant correlations found between the scale and the theoretically relevant variables of perceived health status and symptom patterns. Contrary to expectation, dependency was not related to positive health practices. A post hoc analysis indicated that Factor I correlated significantly with perceived health status and symptom patterns. The results support the use of Factor I, consisting of 13 items, as a measure of general health practices with adolescents. © 2002 John Wiley & Sons, Res Nurs Health 25:68–75, 2002.
Sociospatial knowledge networks: Appraising community as place
Authors: Skelly Anne H. , Arcury Thomas A. , Gesler Wilbert M. , Cravey Altha J. , Dougherty Molly C. , Washburn Sarah A. , Nash Sally
Published: August 2002

This article introduces a new theory of geographical analysis, sociospatial knowledge networks, for examining and understanding the spatial aspects of health knowledge (i.e., exactly where health beliefs and knowledge coincide with other support in the community). We present an overview of the theory of sociospatial knowledge networks and an example of how it is being used to guide an ongoing ethnographic study of health beliefs, knowledge, and knowledge networks in a rural community of African Americans, Latinos, and European Americans at high risk for, but not diagnosed with, type 2 diabetes mellitus. We believe that the geographical approach to understanding health beliefs and knowledge and how people acquire health information presented here is one that could serve other communities and community health practitioners working to improve chronic disease outcomes in diverse local environments. © 2002 Wiley Periodicals, Inc. Res Nurs Health 25:159–170, 2002
Testing a model of exercise behavior in older adults
Authors: Resnick Barbara
Published: August 2002

The purpose of this study was to test a model of exercise behavior in older adults. It was hypothesized that (a) mental and physical health directly influence self‐efficacy expectations; (b) mental and physical health, age, and self‐efficacy expectations influence outcome expectations; and (c) all these variables directly and/or indirectly influence exercise behavior. The sample was composed of 175 older adults living in a continuing‐care retirement community, each of whom was interviewed once. Seven of the 10 hypothesized paths were significant. Physical health, self‐efficacy expectations, and outcome expectations directly influenced exercise behavior, and age and mental health indirectly influenced exercise through self‐efficacy expectations and outcome expectations. Combined these variables accounted for 30% of the variance in exercise behavior. To improve exercise behavior in older adults, health care providers should focus on developing interventions to strengthen self‐efficacy and outcome expectations related to exercise. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 83–92, 2001
Name that rat: molecular and morphological identification of Pacific rodent remains
Authors: Matisoo‐Smith Elizabeth , Allen John S.
Published: August 2002

Generally, species identification of rodent remains from archaeological sites in the Pacific is made based on the overall size and robusticity of those bones most commonly recovered—mandibles and femora. Molecular identifications of Pacific rat remains suggest that the current method of morphological identification may not be appropriate for species identification. It appears that there is a high degree of size variation in Rattus exulans throughout the Pacific, and an overlap in size between R. exulans and other rat species present in the region. Our results suggest not only a need to re‐examine our current methods for identification of rodent skeletal remains, but also, perhaps, our views on the distribution of various rodent species throughout the Pacific, and the implications of such for the human prehistory of the region. Copyright © 2001 John Wiley & Sons, Ltd.
Institutional pluralism in public administration and politics: applications in Bolivia and beyond
Authors: Blair Harry
Published: August 2002

In their book Administrative Decentralization: Strategies for Developing Countries, John Cohen and Steven Peterson construct a model they call ‘institutional pluralism’, which they contend is superior to more traditional modes of decentralization. It is characterized chiefly by multiple channels of service provision, thus inducing accountability into a sphere where previously there has been very little. While they restrict their analysis to the administrative realm, this article argues that the institutional pluralist model makes at least as much sense in political decentralization. Bolivia, which recently launched political reforms offering three separate structures linking citizen to state, serves as an excellent illustration of institutional pluralism in politics. This approach shows considerable promise for implementation in other settings, as can be seen in El Salvador, and a case can be made for its replication potential elsewhere as well. Copyright © 2001 John Wiley & Sons, Ltd.
Risk, rule and reason: leadership in Africa
Authors: Goldsmith Arthur A.
Published: August 2002

Why are most African countries poorly led? This article looks at the question from the perspective of political economy, considering leaders to be individuals who respond rationally to incentives created by their environment. Critical is the level of risk, which can encourage leaders to pursue short‐term, economically destructive policies. Using a new database of national leadership transitions in Africa since 1960, the article demonstrates that the risks of office holding are very high in the region. It also finds that African countries where leaders face less risk tend to have more open economic regimes and to have lower levels of perceived political corruption, as predicted by political economy theory. Because it makes the political environment less perilous, democratization in the region holds out some hope for encouraging leaders to govern with an eye to longer‐term results. Copyright © 2001 John Wiley & Sons, Ltd.
Paying for grades: Impact of merit‐based financial aid on educational quality
Authors: Henry Gary T. , Rubenstein Ross
Published: August 2002

In contrast to education reform efforts that target teachers and schools, merit‐based financial aid
for college increases the incentives for high school students and their families to directly affect the quality
of education by investing more time and effort in schoolwork. Large‐scale merit‐based aid
programs, such as Georgia's HOPE Scholarship, seek to improve education by encouraging students to meet
higher standards, in this case by obtaining a 3.0 grade point average in high school and college. Since the HOPE
program began in 1993, the number of high school graduates qualifying for the aid has steadily increased to more
than 38,000 graduates in the class of 1998, or 59.5 percent of the graduating class. At the same time, the
relationship between grades and achievement has remained consistent or, in some cases, improved since HOPE
began. In fact, African–American males and females with a 3.1 high school core course grade point average
have increased their average Scholastic Assessment Test (SAT) scores by more than 20 points. This
indicates that merit‐based aid has improved the quality of K–12 education in Georgia and reduced
racial performance disparities by motivating students and their families to commit greater effort to schooling.
© 2002 by the Association for Public Policy Analysis and Management.
Structural characteristics of p‐t‐Octylphenol formaldehyde resole resins using molecular simulation
Authors: Choi Sung‐Seen
Published: August 2002

p‐t‐Octylphenol formaldehyde resole resins have two linkage types of methylene‐ and dimethylene ether‐linkages and have three terminal types of hydrogen, methylol, and o‐methylene quinone. Variation of structural characteristics of the resins due to different types of linkages and terminals were studied using molecular dynamics and molecular mechanics. The structural characteristics of the methylene‐bridged resins were intramolecular hydrogen bonds between hydroxyl groups of the adjacent p‐t‐octylphenols. In the dimethylene ether‐bridged resin, the intramolecular hydrogen bonds between oxygen atoms of the dimethylene ether‐linkages and hydroxyl groups of the neighboring phenolic units were found. For the resins with both methylol terminals, one of both terminals of the resins was hidden at the center of the molecule when the resin size is large. The number of hydrogen bonds in the resins with the methylol terminal was larger than for the resins with the o‐methylene quinone terminal. Variation of the structural characteristics of the resins by dehydration of the terminal methylol was discussed. Using the calculated results, dissociation of the dimethylene ether linkage and crosslinking reaction of rubber chains by the resin were explained. Copyright © 2002 John Wiley & Sons, Ltd.
Cyclin A expression in superficial spreading malignant melanomas correlates with clinical outcome
Authors: Ann Flørenes Vivi , Mari Mælandsmo Gunhild , Faye Ragnar , Nesland Jahn M. , Holm Ruth
Published: August 2002

The present study analysed by immunohistochemistry the protein level of cyclin A and Ki‐67 in a panel of paraffin‐embedded tissue obtained from 172 primary (110 superficial and 62 nodular) and 73 metastatic melanomas, and ten benign naevi. Since cyclin A exists in the same quaternary complex in the S‐phase of the cell cycle as the cdk inhibitor p21WAF1/CIP1, the levels of the two proteins were compared. Cyclin A and Ki‐67 were heterogeneously expressed in the malignant tumours, whereas in benign naevi, only rare positive cells were detected. In superficial spreading melanomas, the cyclin A level was related to tumour thickness, with less expression in thinner lesions (p<0.00001), and to Ki‐67 (p<0.00001) and p21WAF1/CIP1 (p=0.01) scores. Multivariate analysis showed that in addition to the depth of the primary tumour, the protein level of cyclin A was an independent indicator of relapse‐free period (thickness, p<0.00001; cyclin A, p=0.0003). In contrast, in nodular melanoma, the cyclin A level was associated with Ki‐67 expression, but neither cyclin A nor Ki‐67 was related to tumour thickness (cyclin A, p=0.06; Ki‐67, p=0.61) and neither had any impact on relapse‐free (cyclin A, p=0.64; Ki‐67, p=0.32) or overall (cyclinA, p=0.94; Ki‐67, p=0.45) survival. In conclusion, the results indicate that cyclin A is a strong prognostic factor for patients with superficial spreading melanomas. In nodular melanomas, the proliferation rate seems to have little impact on disease progression. Copyright © 2001 John Wiley & Sons, Ltd.
A simple, rapid method for HPLC analysis of lycopene isomers
Authors: Ishida Betty K. , Ma Jason , Chan Bock
Published: August 2002

A rapid method for the extraction, separation and quantification of the geometric isomers of lycopene and β‐carotene from tomato fruit is described. Carotenoids in tomato were separated and eluted using a reversed‐phase HPLC with a C30 column and a mobile phase consisting of methyl‐t‐butyl ether, methanol and ethyl acetate. The system provided sharp resolution of cis‐ and trans‐isomers of lycopene within approximately 23 min in contrast to the longer and more complex gradient procedures required by previously described methods. Experiments indicate that the stability of extracts of fresh tomato may be improved if stored at −20°C, and that the presence of the antioxidant BHA has no apparent effect on stability. Copyright © 2001 John Wiley & Sons, Ltd.
Aspects of biopsy procedures prior to preimplantation genetic diagnosis
Authors: De Vos Anick , Van Steirteghem André
Published: August 2002

Today, preimplantation genetic diagnosis (PGD) is offered in over 40 centres worldwide for an expanded range of genetic defects causing disease. This very early form of prenatal diagnosis involves the detection of affected embryos by fluorescent in situ hybridization (FISH) (sex determination or chromosomal defects) or by polymerase chain reaction (PCR) (monogenic diseases) prior to implantation. Genetic analysis of the embryos involves the removal of some cellular mass from the embryos (one or two blastomeres at cleavage‐stage or some extra‐embryonic trophectoderm cells at the blastocyst stage) by means of an embryo biopsy procedure. Genetic analysis can also be performed preconceptionally by removal of the first polar body. However, additional information is then often gained by removal of the second polar body and/or a blastomere from the embryo. Removal of polar bodies or cellular material from embryos requires an opening in the zona pellucida, which can be created in a mechanical way (partial zona dissection) or chemical way (acidic Tyrode's solution). However, the more recent introduction of laser technology has facilitated this step enormously. Different biopsy procedures at different preimplantation stages are reviewed here, including their pros and cons and their clinical applications. The following aspects will also be discussed: safety of zona drilling by laser, use of Ca2+/Mg2+‐free medium for decompaction, and removal of one or two cells from cleavage‐stage embryos. Copyright © 2001 John Wiley & Sons, Ltd.
Ultrasound‐guided umbilical cord occlusion using bipolar diathermy for Stage III/IV twin–twin transfusion syndrome
Authors: Taylor M. J. O. , Shalev E. , Tanawattanacharoen S. , Jolly M. , Kumar S. , Weiner E. , Cox P. M. , Fisk N. M
Published: August 2002

Objectives

To evaluate bipolar diathermy as a technique for selective fetocide in the treatment of advanced (Stage III/IV) twin–twin transfusion syndrome (TTTS).

Methods

A prospective observational study in two tertiary referral fetal medicine centres: Queen Charlotte's Hospital, London, UK and Haemek Hospital, Afula , Israel. Fifteen cases of TTTS (14 twins and one triplet pregnancy) were treated by selective occlusion of either the donor (n=8) or recipient's (n=7) umbilical cord using ultrasound‐guided bipolar diathermy. Following each procedure, patients were scanned serially for fetal growth, liquor volume and umbilical Doppler measurements. Procedural complications and obstetric outcome were recorded. Postnatal placental injection studies were performed.

Results

Overall co‐twin survival in Stage III/IV TTTS was 13/14 (93%). There were no treatment failures. The incidence of preterm prelabour rupture of membranes (PPROM) within 3 weeks of the procedure was 3/15 (20%). In those cases where pre‐procedure umbilical artery Dopplers were abnormal, the Doppler findings normalised post‐procedure in all non‐cord‐occluded fetuses. Growth velocities of surviving donors were similar to those of surviving recipients.

Conclusions

Bipolar diathermy appears an effective technique for the selective reduction of monochorionic twins complicated by severe as well as preterminal TTTS, with recipient and donor fetuses being equally appropriate choices for fetocide. We suggest that for advanced‐stage disease where the parents can contemplate this option, cord occlusion as a single pre‐emptive procedure maximises the opportunity for intact survival of a single survivor. Copyright © 2002 John Wiley & Sons, Ltd.
Fluorescence in situ hybridization (FISH) for rapid detection of aneuploidy: experience in 911 prenatal cases†
Authors: Weremowicz Stanislawa , Sandstrom Deborah J. , Morton Cynthia C. , Niedzwiecki Catherine A. , Sandstrom Mary McH. , Bieber Frederick R.
Published: August 2002

Fluorescence in situ hybridization (FISH) was performed with probes specific for chromosomes 13, 18, 21, X and Y on 911 of 11123 (8.2%) amniotic fluid samples submitted to the present authors' laboratory for cytogenetic analysis over an 8‐year period. Altogether 3516 hybridizations were performed with an interpretable FISH result on all chromosomes requested in 884/911 (97%) of cases. An uninformative FISH result occurred in 44 hybridizations among 27 cases (3%). Of a total of 89 karyotypically proven cases with aneuploidy that might have been detected by FISH, the overall detection rate was 84%. An inconclusive or incomplete FISH result occurred in 9/89 (10%) of these proven aneuploid cases. In the remaining 80 informative proven aneuploid cases, correct detection of aneuploidy was accomplished in 75/80 (94%) of samples. A false‐negative result occurred in the remaining 5/80 (6%) of such informative cases. Eighteen cases had karyotypically proven abnormalities that could not have been detected by the targeted FISH. Aside from these 18 cases, FISH allowed correct detection of normal disomy in 785/804 (98%) of such cases. An incomplete FISH result occurred in 18 normal disomic cases. There was a single possible ‘false‐positive’ FISH result for chromosome 21. Interphase FISH analysis of uncultured amniotic fluid cells has been shown to be a useful laboratory tool for rapid fetal aneuploidy screening during pregnancy. As with all clinical laboratory diagnostic tests, incomplete or inconclusive results (or even interpretive errors) occur in a small percentage of cases. Nevertheless, FISH results accompanied by other data and by appropriate counseling provide clinicians and patients with valuable information for clinical decision‐making surrounding family planning and pregnancy management. Copyright © 2001 John Wiley & Sons, Ltd.
Prenatal diagnosis of mosaic tetrasomy 5p
Authors: Park Jonathan P. , Barefoot Katharine H. , Ornvold Kim , Berg Susan Z. , Dossu Josiane R. , Mohandas T. K.
Published: August 2002

We report the prenatal diagnosis of a fetus with tetrasomy 5p mosaicism resulting from a supernumerary isochromosome for the short arm of chromosome 5. The pregnancy was terminated and fetal autopsy revealed minor facial abnormalities (long philtrum, up‐slanting palpebral fissures and a broad nasal bridge). Cultures were established from fetal skin, kidney, and pancreas for cytogenetic analysis; the i(5p) was observed only in the skin fibroblasts. To our knowledge, this is the fourth report of mosaic tetrasomy 5p and the first report of prenatal diagnosis of this abnormality. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of a small supernumerary marker chromosome, r(2)(p10q11.2), and the problem of determining prognosis
Authors: Villa N. , Riva P. , Colombo D. , Sala E. , Mariani S. , Zorloni C. , Crosti F. , Dalprà L.
Published: August 2002

The identification of small supernumerary marker chromosomes (SMCs) and the elucidation of their clinical significance remain two of the problems in classical human cytogenetics. We observed a small supernumerary ring in amniotic fluid cell cultures and identified its origin as r(2)(p10q11.2) and its extent by means of fluorescent in situ hybridisation (FISH). Uniparental disomy (UPD) was excluded by microsatellite analysis using polymorphic markers localised in the same region. On the basis of normal ultrasonographic checks, the patient decided to continue the pregnancy. A normal female was delivered at term and subsequent neonatal follow‐ups confirmed the normal phenotype and development. In the present case, genetic counselling was not helpful because of the absence of reference cases. Detailed characterisation made it possible to correlate the normal baby phenotype with the trisomic 2p10‐2q11.2 genomic region. Further molecular cytogenetic investigations of SMCs classified by DNA content and pregnancy outcome data should improve genetic counselling and risk evaluation. Copyright © 2001 John Wiley & Sons, Ltd.
Predictability of C‐peptide for autoimmune diabetes in young adult diabetic patients
Authors: Törn Carina , Landin‐Olsson Mona , Scherstén Bengt
Published: August 2002

C‐peptide is measured to evaluate the endogenous insulin production. Since the secretion of both insulin and C‐peptide are stimulated by food intake, the sampling procedure is standardized to fasting conditions. The aim of this study was to evaluate the difference in C‐peptide levels in fasting and non‐fasting states in diabetic patients and also to investigate the use of fasting and non‐fasting C‐peptide as instruments to discriminate between diabetes with autoimmune markers (islet cell antibodies, glutamic acid decarboxylase antibodies or antibodies against tyrosine phosphatase) and without autoimmune markers at diagnosis. In patients with autoimmune markers, the median level of C‐peptide was slightly lower in the fasting state (n=283; 0.27; 0.16–0.36 nmol/L) compared to C‐peptide levels in the non‐fasting state (n=138; 0.30; 0.20–0.52 nmol/L; p=0.0066). In patients without autoimmune markers, C‐peptide levels were lower in fasting patients (n=105; 0.51; 0.28–0.76 nmol/L) compared to non‐fasting patients (n=38; 0.74; 0.39–1.1 nmol/L; p=0.011). The highest positive predictive value (94%) for autoimmune diabetes was observed for a C‐peptide below 0.30 nmol/L in the non‐fasting condition.

We conclude that C‐peptide can be taken either fasting or randomly in patients with type 1 diabetes since the beta cell function was stimulated only to a limited extent by food intake. At the time of diagnosis, C‐peptide can prefarably be taken randomly during the day since this improves the discrimination between patients with and without autoimmune markers. Copyright © 2001 John Wiley & Sons, Ltd.
Fate of abstracts presented at five International Conferences on Pharmacoepidemiology (ICPE): 1995–1999
Authors: Stolk P. , Egberts A. C. G. , Leufkens H. G. M.
Published: August 2002

Background

Meetings are an important way of exchanging scientific information, but full diffusion of new information can only be achieved when results are published in scientific journals.

Purpose

(1) To determine the publication frequency of accepted abstracts for the yearly international conferences on pharmacoepidemiology (ICPE) and to examine predicting variables; (2) if published, to determine impact differences between ‘oral’ and ‘poster’ abstracts and to determine type and nature of publishing journals.

Results

Overall, one out of three abstracts resulted in a publication in the peer‐reviewed journals studied. Abstracts from North America were more often presented orally than abstracts from Europe, but had lower publication chances. ‘Oral’ abstracts were more likely to be published than ‘poster’ abstracts; abstracts with a strong methodological content had a lower publication frequency. Most of the published abstracts were found in pharmacology and pharmacy journals (33%) and journals on specific clinical topics (30%).

Conclusions

Only one out of three papers presented at ICPE ends up in established peer‐reviewed journals. Although the publication characteristics for ICPE are not very different from other conferences, there are certain questions that warrant further investigation. Copyright © 2002 John Wiley & Sons, Ltd.
Variability in abciximab (ReoPro®) prescribing: evidence based or budget driven?
Authors: Zwart‐van Rijkom J. E. F. , Leufkens H. G. M. , Simoons M. L. , Broekmans A. W.
Published: August 2002

Purpose

Abciximab improves outcomes in patients undergoing percutaneous transluminal coronary intervention (PTCA). Clinicians, however, have expressed concerns that they do not have enough budget to administer abciximab to all eligible patients. We studied the patterns of prescribing of abciximab and identified factors that correlate with the level of usage.

Methods

In each of all 13 Dutch PTCA centres one opinion‐leading cardiologist was approached to provide data on the abciximab prescribing in their centre and to co‐operate in an interview on this topic. We performed linear regression analysis in which the level of abciximab prescribing was the dependent variable. Potential determinants investigated were the number of PTCAs performed, the criteria for abciximab prescribing, funding and possible financial restrictions, participation in clinical trials in the past, percentage stenting, and desired level of abciximab prescribing.

Results

All 13 PTCA centres in the Netherlands participated in our study. The level of abciximab prescribing varied from 2 to 36% of all PTCAs. The criteria for patient selection significantly differed between centres. Together budget, investigatorship, size, and type of the institution were highly predictive for the level of abciximab prescribing (R2 = 0.93, p < 0.001). The more patients doctors had included in clinical trials in the past, the higher was the likelihood that they had prescribed abciximab.

Conclusions

Shortly after its introduction, patterns of abciximab prescribing varied widely between PTCA centres. There was no agreement on which patients to select for this preventive treatment. Budget and involvement in clinical trials in the past were important predictors of the level of prescribing in each centre. Copyright © 2002 John Wiley & Sons, Ltd.
Front and rear silicon‐nitride‐passivated multicrystalline silicon solar cells with an efficiency of 18.1%
Authors: Mittelstädt L. , Dauwe S. , Metz A. , Hezel R. , Häßler C.
Published: August 2002

A solar cell process designed to utilise low‐temperature plasma‐enhanced chemical vapour deposited (PECVD) silicon nitride (SiNx) films as front and rear surface passivation was applied to fabricate multicrystalline silicon (mc‐Si) solar cells. Despite the simple photolithography‐free processing sequence, an independently confirmed efficiency of 18.1% (cell area 2 × 2 cm2) was achieved. This excellent efficiency can be predominantly attributed to the superior quality of the rear surface passivation scheme consisting of an SiNxfilm in combination with a local aluminium back‐surface field (LBSF). Thus, it is demonstrated that low‐temperature PECVD SiNxfilms are well suited to achieve excellent rear surface passivation on mc‐Si. Copyright © 2002 John Wiley & Sons, Ltd.
Strategies used by teachers to rate student behavior
Authors: Brennan O'Neill Kathleen , Liljequist Laura
Published: August 2002

Upon completing the Teacher Report Form (TRF; Achenbach, 1991) on a randomly selected child in their current classroom, teachers were surveyed about the approaches or strategies they used to formulate their ratings. In Phase 1, teachers identified eight rating strategies. In Phase 2, a new group of teachers indicated the extent to which they relied on the eight strategies. Rather than the two approaches hypothesized to be foremost, (“I compared the child to other children in the same classroom,” “I compared the child to other children of the same age”), teachers relied primarily on their “experience with the child in many different settings.” © 2002 John Wiley & Sons, Inc.
Self‐report objective measures of personality for children: A review of psychometric properties for RQC
Authors: Burns Matthew K.
Published: August 2002

Knoff (1995) indicated that Referral Question Consultation (RQC) can be applied to personality assessment and suggested several self‐report objective measures that could be consistent with this approach. The current article reviews the tools mentioned by Knoff, including the Children's Personality Questionnaire, The Millon Adolescent Clinical Inventory, The Minnesota Multiphasic Personality Inventory–Adolescents, The Personality Inventory for Youth, and The Self Report of Personality (SRP) from the Behavior Assessment System for Children. Each review addressed the reliability of the scales and composite scores, validity, usefulness of results for planning interventions, the empirical basis for analyses of individual items, and whether each measure accounted for response biases. The appropriateness of each for use with RQC, and individual strengths and weaknesses varied considerably. Therefore, practitioners should keep each test's limitations in mind when using it for intervention planning, and future research is needed to validate the tools for this purpose. © 2002 Wiley Periodicals, Inc.
Polymerization of cyclic imino ethers: From its discovery to the present state of the art
Authors: Kobayashi Shiro , Uyama Hiroshi
Published: August 2002

Topics concerning the cationic ring‐opening polymerization of cyclic imino ethers and functional material production based on the resulting polymers are reviewed. Cyclic imino ethers are readily subjected to isomerization polymerization via cationic initiators. Mechanistic studies have provided a new concept, electrophilic polymerization. Double isomerization polymerization and no‐catalyst alternating copolymerization are interesting examples that show characteristics of the ring opening of cyclic imino ethers. The living polymerization of these monomers affords precisely controlled polymeric materials. Through the use of the unique properties of the product polymers, various functional polymeric materials, such as polymeric nonionic surfactants, compatibilizers, hydrogels, stabilizers for dispersion polymerization, biocatalyst modifiers, and supramolecular assemblies, have been developed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 192–209, 2002
Poly(phenylene ethynylene)s with alkoxyphenyl substituents
Authors: Spiliopoulos Ioakim K. , Mikroyannidis John A.
Published: August 2002

Two new poly(phenylene ethynylene)s with alkoxyphenyl substituents were synthesized and characterized. The polymers were amorphous, dissolved readily in common organic solvents, and showed glass‐transition temperatures at 162–175 °C. They showed blue photoluminescence both in solution and in the solid state due to the steric interaction between the substituents and the main chain that caused an interruption of the conjugation length. The quantum yields in a tetrahydrofuran solution were up to 0.63. Excimer emission was the dominant product of the photoexcitation of thin films of the polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1449–1455, 2002