bluuebunny/crossref_metadata_2025 huggingface dataset:
MRI mapping of cerebrovascular reactivity using square wave changes in end‐tidal PCO2
Authors: Vesely Alex , Sasano Hiroshi , Volgyesi George , Somogyi Ron , Tesler Janet , Fedorko Ludwik , Grynspan Jonathan , Crawley Adrian , Fisher Joseph A. , Mikulis David
Published: August 2002

Cerebrovascular reactivity can be quantified by correlating blood oxygen level dependent (BOLD) signal intensity with changes in end‐tidal partial pressure of carbon dioxide (PCO2). Four 3‐min cycles of high and low PCO2 were induced in three subjects, each cycle containing a steady PCO2 level lasting at least 60 sec. The BOLD signal closely followed the end‐tidal PCO2. The mean MRI signal intensity difference between high and low PCO2 (i.e., cerebrovascular reactivity) was 4.0 ± 3.4% for gray matter and 0.0 ± 2.0% for white matter. This is the first demonstration of the application of a controlled reproducible physiologic stimulus, i.e., alternating steady state levels of PCO2, to the quantification of cerebrovascular reactivity. Magn Reson Med 45:1011–1013, 2001. © 2001 Wiley‐Liss, Inc.
Diffusion time dependence of the apparent diffusion tensor in healthy human brain and white matter disease
Authors: Clark Chris A. , Hedehus Maj , Moseley Michael E.
Published: August 2002

The diffusion time dependence of the brain water diffusion tensor provides information regarding diffusion restriction and hindrance but has received little attention, primarily due to limitations in gradient amplitude available on clinical MRI systems, required to achieve short diffusion times. Using new, more powerful gradient hardware, the diffusion time dependence of tensor‐derived metrics were studied in human brain in the range 8–80 ms, which encompasses the shortest diffusion times studied to date. There was no evidence for a change in mean diffusivity, fractional anisotropy, or in the eigenvalues with diffusion time in healthy human brain. The findings are consistent with a model of unrestricted, but hindered water diffusion with semipermeable membranes, likely originating from the extracellular space in which the average extracellular separation is less than 7 microns. Similar findings in two multiple sclerosis plaques indicated that the size of the water diffusion space in the lesion did not exceed this dimension. Magn Reson Med 45:1126–1129, 2001. © 2001 Wiley‐Liss, Inc.
Significant precision improvement for temperature mapping
Authors: Li Lin , Shapiro Erik M. , Leigh John S.
Published: August 2002

MR temperature measurements are important for applications such as the evaluation of thermal therapies and radiofrequency (RF) coil heating effects. In this work the spherical mean value (SMV) method has been applied to significantly improve the precision of MR temperature mapping in a homogeneous gel phantom. Temperature‐increase maps of the phantom were obtained with three‐dimensional (3D) MR phase difference mapping after heating with the RF coil. The temperature‐increase distribution in most regions in the phantom is a harmonic function with the mean value property. Based on this property, the precision of temperature‐increase maps was improved up to sixfold with the SMV method. Comparison of this method with conventional smoothing, further precision improvement, and the in vivo application of the SMV method are discussed. Magn Reson Med 4:678–682, 2001. © 2001 Wiley‐Liss, Inc.
Comparison of potentiated and unpotentiated twitches as an index of muscle fatigue
Authors: Kufel Thomas J. , Pineda Lilibeth A. , Mador M. Jeffery
Published: August 2002

Recent data suggest that the potentiated twitch is a more sensitive index of contractile fatigue than is the unpotentiated twitch. We hypothesized that after a potentially fatiguing load, the fall in twitch amplitude of the potentiated twitch would be significantly greater than that of an unpotentiated twitch. We compared the response of the potentiated and unpotentiated twitches to a series of potentially fatiguing loads using magnetic stimulation of the femoral nerve in 10 healthy subjects. The baseline unpotentiated quadriceps twitch force (TwQu), potentiated quadriceps twitch force (TwQp), and maximal voluntary contraction (MVC) were 129 ± 6 N, 198 ± 6 N, and 622 ± 25 N, respectively. During a fatigue protocol that was designed to induce a spectrum of fatigue from mild to marked, the percent fall in quadriceps twitch force was significantly greater for the potentiated method than for the unpotentiated method at all levels of fatigue (P < .005). The within‐subject within‐day coefficient of variation was 7.5 ± 0.5% for TwQu and 5.6 ± 0.9% for TwQp. Thus, TwQp is reproducible and is superior to TwQu for detecting early muscle fatigue. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Informed consent
Authors: Bernat James L.
Published: August 2002

Physicians have an ethical and legal duty to obtain patients' informed consent before ordering testing and treatment. Informed consent encompasses informed refusal, the correlative right of patients to refuse tests and therapies they do not want. A patient's informed consent requires adequate information, capacity to decide, and absence of coercion. Informed consent is incorporated into a process of agreement between a patient and a physician called “shared decision making.” The procedural requirements of informed consent vary as a function of the risks of the tests or treatments. Incompetent patients require surrogate decision makers to consent or refuse on their behalf. Older children and adolescents should be asked to provide their assent for treatment in addition to their parents' permission. Treatment may be provided in an emergency situation without consent if the treatment given represents the standard of emergency care. Consent of human subjects for participation in research requires that they fully understand their role and risks, not be coerced, and be allowed to withdraw at any time without penalty. Institutional review boards help guarantee the protection of human subjects. Vulnerable research subjects, such as children and the cognitively or mentally impaired, require additional protection. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 614–621, 2001
An innovative hand brace for carpal tunnel syndrome: A randomized controlled trial
Authors: Manente G. , Torrieri F. , Di Blasio F. , Staniscia T. , Romano F. , Uncini A.
Published: August 2002

We developed a hand brace and studied its efficacy and tolerability in patients with carpal tunnel syndrome (CTS). We randomized 83 subjects into a treated group, which wore the hand brace at night for 4 weeks, and a control group, which received no treatment. The primary efficacy measure was change in the Boston Carpal Tunnel Questionnaire (BCTQ) score. Secondary measures were Subjects' Global Impression of Change Questionnaire (SGICQ), median distal motor latency, sensory conduction velocity and amplitude, and neurophysiological class of severity. The treated group showed a reduction in BCTQ symptomatic score (from 2.75 to 1.54 at 4 weeks; P < 0.001) and functional score (from 1.89 to 1.48; P < 0.001). There were no significant changes in the control subjects. SGICQ documented improvement in all treated subjects (P = 0.006). No significant difference was found in electrophysiological measurements, but overall neurophysiological classification shifted to less severe classes in the treated group (P < 0.05). Thus, the study demonstrates that this hand brace is highly efficient in relieving symptoms and functional loss in CTS. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1020–1025, 2001
Terminal latency index in polyneuropathy with IgM paraproteinemia and anti‐MAG antibody
Authors: Cocito Dario , Isoardo Gianluca , Ciaramitaro Palma , Migliaretti Giuseppe , Pipieri Antonio , Barbero Pierangelo , Cucci Angele , Durelli Luca
Published: August 2002

Criteria for the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) are met by the polyneuropathy associated with immunoglobulin M (IgM) paraproteinemia and anti‐myelin–associated glycoprotein (MAG) antibody (MAG‐CIDP). However, MAG‐CIDP differs from other types of CIDP, mainly in its poorer response to treatment. The utility of terminal latency index (TLI) as an electrophysiological marker for MAG‐CIDP has been debated. In this study we confirmed its diagnostic usefulness and evaluated TLI threshold values for motor nerves investigated in routine nerve conduction studies. Median, ulnar, peroneal, and tibial TLIs of 11 subjects with MAG‐CIDP, 18 with CIDP, and 76 healthy controls were compared, and threshold values for MAG‐CIDP evaluated as the lowest value with a likelihood ratio higher than 10. Mean TLI values and TLIs of all but the peroneal nerve were significantly lower in MAG‐CIDP. Median nerve TLI of 0.26 and ulnar nerve TLI of 0.33 were identified as the threshold TLI values for MAG‐CIDP. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1278–1282, 2001
Role of supraspinal serotonin receptors for micturition in normal conscious rats
Authors: Ishizuka Osamu , Gu Baojun , Igawa Yasuhiko , Nishizawa Osamu , Pehrson Rikard , Andersson Karl‐Erik
Published: August 2002

Serotonin (5‐HT) receptors are widely distributed in the central nervous system, including several areas involved in the control of micturition reflex pathways. However, the roles of the different subtypes of 5‐HT receptors are not well known. We studied in normal, conscious rats, the effects on the cystometrogram of intracerebroventricular (i.c.v.) administration of 5‐HT, 8‐hydroxy‐2‐(di‐N‐propylaminotetralin) (8‐OH‐DPAT; agonist at 5‐HT1A receptors), α‐methyl‐5‐hydroxytryptamine maleate (agonist at 5‐HT2 receptors), 2‐methyl‐5‐hydroxytryptamine hydrochloride (agonist at 5‐HT3 receptors), and 1‐(4‐amino‐5‐chloro‐2methoxyphenyl)‐3‐(1‐n‐butyl‐4piperidinyl)‐1‐propanone hydrochloride (RS67506; agonist at 5‐HT4 receptors). Female Sprague‐Dawley rats, weighing approximately 230 g, were used. A polyethylene catheter was inserted into the bladder through the dome for cystometric investigations. For administration of drugs, a catheter was implanted into the right cerebral ventricle. Three days after implantation of the bladder catheter, continuous cystometry was performed. Administration of 5‐HT (6 nmol/kg i.c.v.), 8‐OH‐DPAT (6 nmol/kg), α‐methyl‐5‐hydroxytryptamine maleate (6 nmol/kg), or RS67506 hydrochloride (6 nmol/kg) significantly (P < 0.05) increased micturition pressure and decreased bladder capacity and micturition volume. The effects increased in a dose‐dependent manner (18, 60 nmol/kg). Intracerebroventricular administration of 2‐methyl‐5‐hydroxytryptamine hydrochloride (60 nmol/kg) caused no change in the cystometric parameters. The results suggest that in normal conscious rats, at the supraspinal level, 5‐HT (via 5‐HT1A, 5‐HT2, and 5‐HT4 receptors) can enhance the micturition reflex induced by bladder filling. Whether this means that 5‐HT1A, 5‐HT2, and 5‐HT4 receptors can be targets for drugs meant for treatment of bladder hyperactivity, should be explored. Neurourol. Urodynam. 21:225–230, 2002. © 2002 Wiley‐Liss, Inc.
Warehouse sizing to minimize inventory and storage costs
Authors: Goh Mark , Jihong Ou , Chung‐Piaw Teo
Published: August 2002

This paper considers a warehouse sizing problem whose objective is to minimize the total cost of ordering, holding, and warehousing of inventory. Unlike typical economic lot sizing models, the warehousing cost structure examined here is not the simple unit rate type, but rather a more realistic step function of the warehouse space to be acquired. In the cases when only one type of stock‐keeping unit (SKU) is warehoused, or when multiple SKUs are warehoused, but, with separable inventory costs, closed form solutions are obtained for the optimal warehouse size. For the case of multi‐SKUs with joint inventory replenishment cost, a heuristic with a provable performance bound of 94% is provided. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 299–312, 2001
Lactate efflux and the neuroenergetic basis of brain function
Authors: Shulman Robert G. , Hyder Fahmeed , Rothman Douglas L.
Published: August 2002

In the unstimulated brain energy is primarily supplied by the oxidation of glucose. However the oxygen‐to‐glucose index (OGI), which is the ratio of metabolic rates of oxygen to glucose, CMRO2/CMRglc, diverges from the theoretical value of 6 as activity is increased. In vivo measurements of brain lactate show its concentration to increase with stimulation. The decreasing OGI with stimulation had led to the suggestion that activation, unlike resting activity, is supported by anaerobic glycolysis. To date a unifying concept that accommodates glucose oxidation at rest with lactate generation and OGI decrease during stimulation of brain is lacking. Furthermore, energetics that change with increasing activity are not consistent with a neuroenergetic model that has been proposed from 1‐13C‐glucose MRS experiments. That model, based upon in vivo MRS measurements and cellular studies by Pellerin and Magistretti, showed that glutamate neurotransmitter cycling was coupled to glucose oxidation over a wide range of brain activities from rest down to deep anesthesia. Here we reconcile these paradoxical observations by suggesting that anaerobic glucose consumption (which can provide energy rapidly) increases with activation to meet the power requirements of millisecond neuronal firing. It is proposed, in accord with our neuroenergetic model, that the extra glucose mobilized rapidly for glial clearance of glutamate, is not needed for the oxidative processes that are responsible for neuronal firing and glutamate release, and consequently it is effluxed as lactate. A stoichiometric relation between OGI and lactate concentration is derived from the neuroenergetic model, showing that the enhanced glucose uptake during activation is consistent with neuronal activity being energetically supported by glucose oxidation. Copyright © 2001 John Wiley & Sons, Ltd.
From voice‐band modems to DSL technologies
Authors: Peden Mark , Young Gavin , Sokol Allison
Published: August 2002

This paper provides an overview of the evolution of digital transmission in the copper access network from voice‐band modems to Digital Subscriber Line (DSL) technologies. The various types of DSL technology are described. Copyright © 2001 John Wiley & Sons, Ltd.
Multiphoton stimulation of neurons
Authors: Hirase Hajime , Nikolenko Volodymyr , Goldberg Jesse H. , Yuste Rafael
Published: August 2002

We pulsed the activation of neurons using a femtosecond laser. Pyramidal neurons are depolarized and fire action potentials when high intensity mode‐locked infrared light irradiates somatic membranes and axon initial segments. This depolarization is reversible, does not occur with CW laser light, and appears to be due to multiphoton excitation. We describe two regimes of multiphoton optical stimulation. Low intensity, long duration laser irradiation produces a sustained depolarization, insensitive to sodium channel blockers yet sensitive to antioxidants. On the other hand, high intensity, short duration irradiation can induce fast depolarizations, which appear due to different mechanism. The combination of multiphoton stimulation and optical probing could enable systematic analysis of circuits. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 237–247, 2002
Testosterone regulates the activity and expression of aromatase in the canary neostriatum
Authors: Fusani Leonida , Hutchison John B. , Gahr Manfred
Published: August 2002

The estrogen synthesizing enzyme, P450 aromatase, plays a critical role in the regulation of vertebrate sexual behavior. Songbirds differ from other avian species in the distribution and expression of aromatase in the telencephalon. The highest concentration of aromatase in the songbird brain is found in the caudomedial neostriatum (NCM). This area surrounds the only nucleus of the neural song system that contains estrogen receptors, the high vocal center (HVC). It has been suggested that estrogen produced in NCM via aromatization of circulating testosterone (T) is involved in song development and adult song plasticity. The modalities of regulation of aromatase in NCM are not well understood, and some studies suggest that in NCM, unlike in the preoptic‐hypothalamic areas, aromatase is not regulated by androgen and/or estrogen. In this work, we studied whether the treatment of female canaries with T, which induces the development of malelike song and the masculinization of the song system, also induces an increase in the expression and activity of aromatase in NCM. Our results show that both the expression and activity of aromatase in NCM increase in female canaries following T treatment. This study provides the first direct evidence that T regulates telencephalic aromatase in songbirds, and suggests that an increase in estrogen production in NCM might be functional in neural and behavioral plasticity during phases of song organization. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 1–8, 2001
Immunoelectron microscopic localization of the neural recognition molecules L1, NCAM, and its isoform NCAM180, the NCAM‐associated polysialic acid, beta1 integrin and the extracellular matrix molecule tenascin‐R in synapses of the adult rat hippocampus
Authors: Schuster Thomas , Krug Manfred , Stalder Martina , Hackel Natalie , Gerardy‐Schahn Rita , Schachner Melitta
Published: August 2002

We have investigated the possibility that morphologically different excitatory glutamatergic synapses of the “trisynaptic circuit” in the adult rodent hippocampus, which display different types of long‐term potentiation (LTP), may express the immunoglobulin superfamily recognition molecules L1 and NCAM, the extracellular matrix molecule tenascin‐R, and the extracellular matrix receptor constituent beta1 integrin in a differential manner. The neural cell adhesion molecules L1, NCAM (all three major isoforms), NCAM180 (the largest major isoform with the longest cytoplasmic domain), beta1 integrin, polysialic acid (PSA) associated with NCAM, and tenascin‐R were localized by pre‐embedding immunostaining procedures in the CA3/CA4 region (mossy fiber synapses) and in the dentate gyrus (spine synapses) of the adult rat hippocampus. Synaptic membranes of mossy fiber synapses where LTP is expressed presynaptically did not show detectable levels of immunoreactivity for any of the molecules/epitopes studied. L1, NCAM, and PSA, but not NCAM180 or beta1 integrin, were detectable on axonal membranes of fasciculating mossy fibers. In contrast to mossy fiber synapses, spine synapses in the outer third of the molecular layer of the dentate gyrus, which display postsynaptic expression mechanisms of LTP, were both immunopositive and immunonegative for NCAM, NCAM180, beta1 integrin, and PSA. Those spine synapses postsynaptically immunoreactive for NCAM or PSA also showed immunoreactivity on their presynaptic membranes. NCAM180 was not detectable presynaptically in spine synapses. L1 could not be found in spine synapses either pre‐ or postsynaptically. Also, the extracellular matrix molecule tenascin‐R was not detectable in synaptic clefts of all synapses tested, but was amply present between fasciculating axons, axon‐astrocyte contact areas, and astrocytic gap junctions. Differences in expression of the membrane‐bound adhesion molecules at both types of synapses may reflect the different mechanisms for induction and/or maintenance of synaptic plasticity. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 142–158, 2001
Two‐dimensional unsteady heat conduction analysis with heat generation by triple‐reciprocity BEM
Authors: Ochiai Yoshihiro
Published: August 2002

If the initial temperature is assumed to be constant, a domain integral is not needed to solve unsteady heat conduction problems without heat generation using the boundary element method (BEM).However, with heat generation or a non‐uniform initial temperature distribution, the domain integral is necessary. This paper demonstrates that two‐dimensional problems of unsteady heat conduction with heat generation and a non‐uniform initial temperature distribution can be solved approximately without the domain integral by the triple‐reciprocity boundary element method. In this method, heat generation and the initial temperature distribution are interpolated using the boundary integral equation. Copyright © 2001 John Wiley & Sons, Ltd.
An assumed strain triangular solid shell element with bubble function displacements for analysis of plates and shells
Authors: Hong Won I. , Kim Yong H. , Lee Sung W.
Published: August 2002

Bubble function displacements are used in conjunction with the assumed strain formulation to construct efficient triangular solid shell elements tailored for shell analysis. Two versions of 36‐DOF triangular elements are presented with different bubble function displacements and the corresponding assumed strain fields. In the first version the bubble function displacement is independent of the thickness while in the second version the bubble function varies linearly in the thickness direction. The assumed strain fields are carefully selected to alleviate locking effect. The first version models curved shells with flat triangular elements. The second version is effective in alleviating the membrane locking and thus allows more accurate modelling of curved shells. Various numerical examples demonstrate the validity and effectiveness of the present assumed strain formulation elements with the bubble function displacements. Copyright © 2001 John Wiley & Sons, Ltd.
Micromechanics of high temperature hydrogen attack
Authors: Schlögl Sabine M. , Van der Giessen Erik
Published: August 2002

Hydrogen attack is a material degradation process that occurs at elevated temperatures in hydrogen‐rich environments, such as found in petrochemical installations. Weldments in components such as reactor vessels are particularly susceptible to hydrogen attack. This paper discusses a multi‐scale micromechanics modelling approach in which the chemico‐mechanical damage processes at sub‐micron scale are coupled to the macroscopic behaviour through a series of size‐scale transitions. A simulation of hydrogen attack in a welded reactor serves as an illustration of the approach. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of individual and family hardiness on caregiver depression and fatigue†
Authors: Clark Patricia C.
Published: August 2002

Hardiness is defined as commitment to life, viewing change as challenge, and having control over one's life. Previous research suggests that hardiness is related to better outcomes in stressful situations. The effects of individual and family hardiness on depression and fatigue of caregivers of disabled older adults (DA) were examined using a descriptive, cross‐sectional design. The sample was 67 caregivers of DA with high functional impairment. One‐third of caregivers reported moderate to high fatigue, and 40% had scores indicating possible clinical depression. Memory and behavior problems of the DA were positively correlated with caregiver depression and fatigue. Family hardiness was negatively related to memory and behavior problems of the DA. Controlling for covariates, individual hardiness was negatively associated with depression and fatigue; coping strategies did not mediate the relationship. Caregivers with low individual and family hardiness had more depression than those high in both resources. Additional research is needed to determine the relevance of hardiness theory in caregiving research. © 2002 John Wiley & Sons, Res Nurs Health 25:37–48, 2002.
Fishing in Peru between 10 000 and 3750 BP
Authors: Reitz Elizabeth J.
Published: August 2002

Archaeozoological data for the period of 10 000–5000 bp were rare for the southeastern Pacific coast, until recent work provided data from eight sites in Peru and Ecuador. These sites span the early to mid‐Holocene period, during which time modern climatic conditions became established. Vertebrate faunal data from these sites provide an opportunity to explore the influence of mid‐Holocene environmental changes on fishing in Peru during this time. With two exceptions, most faunal collections are dominated by marine animals, with virtually no terrestrial vertebrates. Many of the marine organisms are catholic species, tolerant of a wide variety of water conditions, rather than ones which clearly prefer warm–tropical or warm–temperate ones. Warm–tropical species are more common in the northern assemblages, as would be expected. There is a temporal pattern as well. Within three subdivisions of this area, warm–tropical animals diminish in abundance, and warm–temperate animals increase. These differences probably reflect cultural responses to mid‐Holocene environmental change, in which coastal waters from southern Peru into Ecuador became cooler. Copyright © 2001 John Wiley & Sons, Ltd.
Education and training in public administration and development: what does the customer really want and are we prepared to provide it?
Authors: Rubienska Annie
Published: August 2002

This article examines some of the difficulties arising from the introduction of market forces into the field of higher education.In particular it notes how the changing demands of sponsors and other key players, coupled with recent trends in teaching and learning methods, have caused providers of education and training in development to review ‘core products’ and modify the style of service delivery to accommodate the changing expectations of ‘customers.’ Copyright © 2001 John Wiley & Sons, Ltd.
VEGFR‐3 in adult angiogenesis
Authors: Witmer A. N. , van Blijswijk B. C. , Dai J. , Hofman P. , Partanen T. A. , Vrensen G. F. J. M. , Schlingemann R. O.
Published: August 2002

Vascular endothelial growth factor receptor 3 (VEGFR‐3, Flt‐4), the receptor for vascular endothelial growth factors (VEGFs) C and D, is expressed on lymphatic endothelium and may play a role in lymphangiogenesis. In embryonic life, VEGFR‐3 is essential for blood vessel development. The purpose of this study was to investigate whether VEGFR‐3 is also involved in blood vessel angiogenesis in the adult. This was studied in human tissues showing angiogenesis andin a model of VEGF‐A‐induced iris neovascularization in the monkey eye, by the use of immunohistochemistry at the light and electron microscopic level. VEGFR‐3 was expressed on endothelium of proliferating blood vessels in tumours. In granulation tissue, staining was observed in the proliferative superficial zone in plump blood vessel sprouts, in the intermediate zone in blood vessels and long lymphatic sprouts, and in the deeper fibrous zone in large lymphatics, in a pattern demonstrating that lymphangiogenesis follows behind blood vessel angiogenesis in granulation tissue formation. At the ultrastructural level, VEGFR‐3 was localized in the cytoplasm and on the cell membrane of endothelial cells of sprouting blood vessels and sprouting lymphatics. In monkey eyes injected with VEGF‐A, blood vessel sprouts on the anterior iris surface and pre‐existing blood vessels in the iris expressed VEGFR‐3. In conclusion, these results support a role for VEGFR‐3 and its ligands VEGF‐C and/or VEGF‐D in cell‐to‐cell signalling in adult blood vessel angiogenesis. The expression of VEGFR‐3 in VEGF‐A‐induced iris neovascularization and in pre‐existing blood vessels exposed to VEGF‐A suggests that this receptor and possibly its ligands are recruited in VEGF‐A‐driven angiogenesis. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of GC and HPLC for the quantification of organic acids in coffee
Authors: Jham Gulab N. , Fernandes Sergio A. , Garcia Cleverson Fernando , Silva Alexsandro Araujo da
Published: August 2002

A GC and an HPLC method for the quantification of organic acids OAs in coffee have been compared. The GC procedure, employing trimethylsilyl derivatives, was found to be very tedious. The HPLC method, which employed an ion exchange column using a flow gradient of water containing 1% phosphoric acid and UV detection (210 nm), was found to be much simpler for the quantification of eight organic acids (oxalic, succinic, fumaric, malic, tartaric, citric, quinic and fumaric acids) in four representative coffee samples. The HPLC procedure was more convenient than that described in the literature since no pre‐purification was required for quantification of the OAs. Copyright © 2002 John Wiley & Sons, Ltd.
Prenatal findings on ultrasound and X‐ray in a case of overgrowth syndrome associated with increased nuchal translucency
Authors: Schwärzler P. , Homfray T. , Campbell S. , Ville Y.
Published: August 2002

A case of prenatal diagnosis of an overgrowth syndrome at 30 weeks of gestation is reported. The diagnosis was suggested on the basis of increased fetal growth from 16 weeks onwards, advanced bone age, and characteristic facial features such as hypertelorism, broad forehead and small chin. The fetus presented at 12 weeks with a markedly increased nuchal translucency thickness and generalized skin edema, but normal karyotype. Serial ultrasound scans revealed brain abnormalities including mild unilateral ventriculomegaly and a cyst in the cavum septi pellucidi. The pregnancy was terminated at the parents' request at 32 weeks of gestation and postmortem examination confirmed the prenatal findings. This case demonstrates the possibility of prenatal diagnosis of early overgrowth syndromes and highlights the dilemma arising from the prenatal diagnosis of a non‐lethal condition associated with an uncertain prognosis and poorly documented in utero. Copyright © 2001 John Wiley & Sons, Ltd.
Data validity issues in using claims data
Authors: Strom Brian L.
Published: August 2002

This paper overviews the use of claims data in pharmacoepidemiology, examines problems related to claims data use, and focuses on the uncertain validity of diagnosis data. Two contrasting studies are provided of drug‐induced neutropenia and Stevens‐Johnson Syndrome; both studies were launched at the same time with similar designs. Neutropenia is a laboratory‐driven diagnosis, easy to make and confirm. The neutropenia study yielded many useful results, ranging from incidence rates to results with specific drug classes and individual drugs. However, the medical records revealed major unexpected issues from chronic and cyclic neutropenia. In contrast, Stevens‐Johnson Syndrome is harder to diagnose, and is represented poorly in the ICD‐9‐CM coding system. The result was a study productive of much less clinical information. These studies show the important implications of variable data validity to study interpretation. Uniquely problematic situations exist: the illness does not reliably come to medical attention; inpatient drug exposures; an outcome is poorly defined by the diagnostic coding system; descriptive studies; drug effects are delayed and patients lose eligibility; and there are important unknown confounders such as cigarette smoking, occupation, menarche, menopause, etc., about which information cannot be obtained without accessing the patient. Copyright © 2001 John Wiley & Sons, Ltd.
The role of databases in drug postmarketing surveillance
Authors: Rodriguez Evelyn M. , Staffa Judy A. , Graham David J.
Published: August 2002

This paper describes the role of databases used for postmarketing surveillance of drugs at the United States Food and Drug Administration (FDA). First we describe the Adverse Event Reporting System (AERS), the largest database of adverse event reports in the world. Next, we explain the methods we have used for assembling these adverse event reports into a case series and analysing them, as well as techniques for employing drug use databases to construct reporting rates in the evaluation of drug safety issues. Finally, we discuss the FDA's use of the databases it accesses through its Cooperative Agreement Program to conduct high priority studies to support regulatory decision‐making. Published in 2001 by John Wiley & Sons, Ltd.
Types and variables: towards a congenial procedure for handling personality data
Authors: Hofstee Willem K. B.
Published: August 2002

Standard procedures for processing and interpreting data in personality assessment run the risk of losing their audience. Most notably, relative scaling of data, whether through interindividual or intra‐individual comparison, leads to losing either the persons or the variables from view. I set out an alternative, more congenial procedure for handling personality data, consisting of (i) translating assessments to a bipolar bounded scale running from − 1 to + 1, (ii) adopting the uncorrected average cross‐product (ACP) as the index of association or correspondence between variables and between individuals, and (iii) applying raw‐scores principal component analysis to find factors and types. The ACP index appears eminently fit for handling individual (N = 1) cases. Adoption of the congenial procedure would imply a substantive correction of one's views of individual differences in personality and their structure. Copyright © 2002 John Wiley & Sons, Ltd.
Toughening of cyanate ester resin by N‐phenylmaleimide–N‐(p‐hydroxy)phenyl‐maleimide–styrene terpolymers and their hybrid modifiers
Authors: Iijima Takao , Maeda Takanori , Tomoi Masao
Published: August 2002

N‐Phenylmaleimide–N‐(p‐hydroxy)phenylmaleimide–styrene terpolymer (HPMS), carrying reactive p‐hydroxyphenyl groups, was prepared and used to improve the toughness of cyanate ester resins. Hybrid modifiers composed of N‐phenylmaleimide–styrene copolymer (PMS) and HPMS were also examined for further improvement in toughness. Balanced properties of the modified resins were obtained by using the hybrid modifiers. The morphology of the modified resins depends on HPMS structure, molecular weight and content, and hybrid modifier compositions. The most effective modification of the cyanate ester resin was attained because of the co‐continuous phase structure of the modified resin. Inclusion of the modifier composed of 10 wt% PMS (Mw 136 000 g mol−1) and 2.5 wt% HPMS (hydroxyphenyl unit 3 mol%, Mw 15 500 g mol−1) led to 135% increase in the fracture toughness (KIC) for the modified resin with a slight loss of flexural strength and retention of flexural modulus and glass transition temperature, compared with the values for the unmodified resin. Furthermore, the effect of the curing conditions on the mechanical and thermal properties of the modified resins was examined. The toughening mechanism is discussed in terms of the morphological and dynamic viscoelastic behaviour of the modified cyanate ester resin system.

© 2001 Society of Chemical Industry
Third generation photovoltaics: Ultra‐high conversion efficiency at low cost
Authors: Green Martin A.
Published: August 2002

Since the early days of terrestrial photovoltaics, a common perception has been that ‘first generation’ silicon wafer‐based solar cells eventually would be replaced by a ‘second generation’ of lower cost thin‐film technology, probably also involving a different semiconductor. Historically, cadmium sulphide, amorphous silicon, copper indium diselenide, cadmium telluride and now thin‐film polycrystalline silicon have been regarded as key thin‐film candidates. Any mature solar cell technology seems likely to evolve to the stage where costs are dominated by those of the constituent materials, be they silicon wafers or glass sheet. It is argued, therefore, that photovoltaics is likely to evolve, in its most mature form, to a ‘third generation’ of high‐efficiency thin‐film technology. By high efficiency, what is meant is energy conversion values double or triple the 15–20% range presently targeted, closer to the thermodynamic limit of 93%. Tandem cells are the best known of such high‐efficiency approaches, where efficiency can be increased merely by adding more cells of different bandgap to a cell stack, at the expense of increased complexity and spectral sensitivity. However, a range of other more ‘paralleled’ approaches offer similar efficiency to an infinite stack of tandem cells. These options are reviewed together with possible approaches for practical implementation, likely to become more feasible with the evolution of materials technology over the next two decades. Copyright © 2001 John Wiley & Sons, Ltd.
Threats of violence in schools: The Dallas independent school district's response
Authors: Ryan‐Arredondo Kim , Renouf Kristin , Egyad Carla , Doxey Meridith , Dobbins Maria , Sanchez Serafin , Rakowitz Bert
Published: August 2002

School violence has become a primary concern for parents, students, school personnel, and the public. As a result, educators are searching for methods to prevent violent acts perpetrated by youth. Dallas Public Schools developed procedures for assessing the potential for violence among children who express intent to harm others. The Dallas Violence Risk Assessment (DVRA) was developed to evaluate students who have made verbal or written threats of violence and to assist school staff in determining appropriate intervention strategies. This article describes the development of the DVRA, and presents case studies utilizing the DVRA procedures. Challenges and implications of the use of the DVRA are also discussed. © 2001 John Wiley & Sons, Inc.
Psychological characteristics of academically gifted students in a residential setting: A cluster analysis
Authors: Dixon Felicia A. , Cross Tracy L. , Adams Cheryll M.
Published: August 2002

Students in one entering class at a Midwestern residential school for gifted and talented adolescents (N = 156) took three instruments: the Self‐Description Questionnaire III (SDQIII; Marsh, 1988), the Minnesota Multiphasic Personality Inventory for Adolescents (MMPI‐A; Butcher, Williams, Graham, Archer, Tellegen, Ben‐Porath, & Kaemmer, 1992), and the Self‐Perception Profile for Adolescents (SPPA; Harter, 1988) in order to determine the psychological makeup of academically gifted students who are admitted to and leave home to attend a residential school. Scores from the SDQIII were cluster analyzed using Ward's hierarchical method. Clusters were validated using data from the MMPI‐A and the SPPA. Results indicated six different cluster groups that were described as follows: a mathematics focus (21%); a social focus (18%); a nonathletic group (21%); a low overall self‐concept group (16%); a verbal group (9%); and a nonspiritual/religious group (14%). Characteristics of the clusters and implications for residential schools are discussed. © 2001 John Wiley & Sons, Inc.
Second harmonic generation in polymers containing a new azo chromophore based on phenylnitrobenzoxazole
Authors: Bruno Vincenza , Castaldo Anna , Centore Roberto , Sirigu Augusto , Sarcinelli Felice , Casalboni Mauro , Pizzoferrato Roberto
Published: August 2002

The synthesis of the new chromophores 2‐{4‐[4‐(N,N‐dihydroxyethylamino)‐phenylazo]‐phenyl}‐6‐nitrobenzoxazole (1) and 4‐[4‐(N,N‐dihydroxyethylamino)phenylazo]‐benzoic acid (2) is described. Three homopolymers obtained by the polycondensation of 1 with propyloxy‐terephthalic acid and 1 and 2 with 2,4‐tolylenediisocianate as well as two copolymers obtained by polycondensation of appropriate mixtures of chromophores 1 and 2 with 2,4‐tolylene‐diisocianate were prepared and characterized. All as‐prepared polymers but one (homopolyurethane of 1) were amorphous and exhibited good optical clarity, good thermal stability above the glass transition, and solubility in organic solvents. The second‐order nonlinear optical behavior of the amorphous polymers was investigated on spin‐coated corona‐poled films through second harmonic generation (SHG) experiments at 1064 nm. At this wavelength, resonance‐enhanced values of the SHG coefficient d33 were found in the range between 6 and 34 pm/V where higher values were observed for polymers with a higher molar content of 1. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1468–1475, 2002
Preparation and characterization of poly(ethyl acrylate)/bentonite nanocomposites by in situ emulsion polymerization
Authors: Tong Xin , Zhao Haichao , Tang Tao , Feng Zhiliu , Huang Baotong
Published: August 2002

Transparent poly(ethyl acrylate) (PEA)/bentonite nanocomposites containing intercalated–exfoliated combinatory structures of clay were synthesized by in situ emulsion polymerizations in aqueous dispersions containing bentonite. The samples for characterization were prepared through direct‐forming films of the resulting emulsions without coagulation and separation. An examination with X‐ray diffraction and transmission electron microscopy showed that intercalated and exfoliated structures of clay coexisted in the PEA/bentonite nanocomposites. The measurements of mechanical properties showed that PEA properties were greatly improved, with the tensile strength and modulus increasing from 0.65 and 0.24 to 11.16 and 88.41 MPa, respectively. Dynamic mechanical analysis revealed a very marked improvement of the storage modulus above the glass‐transition temperature. In addition, because of the uniform dispersion of silicate layers in the PEA matrix, the barrier properties of the materials were dramatically improved. The permeability coefficient of water vapor decreased from 30.8 × 10−6 to 8.3 × 10−6 g cm/cm2 s cmHg. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1706–1711, 2002
Synthesis and photochemical property of polymers with pendant donor–acceptor‐type norbornadiene moieties
Authors: Kawashima Naoyuki , Kameyama Atsushi , Nishikubo Tadatomi , Nagai Takabumi
Published: August 2002

The donor–acceptor‐type norbornadiene (D–A NBD) 1,4,5,6‐tetramethyl‐3‐phenyl‐2,5‐NBD‐2‐carboxylic acid was prepared by the Diels–Alder reaction of methyl 3‐phenylprop‐2‐ynoate with 1,2,3,4‐tetramethyl‐1,3‐cyclopentadiene. 1,4,5,6,7‐Pentamethyl‐3‐phenyl‐2,5‐NBD‐2‐carboxylic acid was also synthesized in the same way. Styrene‐type polymers with pendant D–A NBD moieties were prepared with a 100% degree of substitution (DS) by the reaction of D–A NBD carboxylic acids with poly[(p‐chloromethyl)styrene] with 1,8‐diazabicyclo[5.4.0]undecene‐7 in dimethyl sulfoxide at 70 °C for 6 h. In the reaction of D–A NBD carboxylic acids with poly(2‐chloroethyl vinyl ether), the DSs were about 60%. The photochemical valence isomerizations of all the NBD polymers proceeded smoothly with UV irradiation in tetrahydrofuran solutions and in the film state. In addition, the rate of the photochemical reaction of the NBD polymers increased efficiently by the addition of 4,4′‐bis(diethylamino)benzophenone as a photosensitizer in a film state. The stored thermal energy of the irradiated polymers was also evaluated by differential scanning calorimetry to be 55–74 kJ/mol. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1764–1773, 2001
Fluoropolyether coatings: Relationships of electrochemical impedance spectroscopy measurements, barrier properties, and polymer structure
Authors: Delucchi M. , Turri S. , Barbucci A. , Bassi M. , Novelli S. , Cerisola G.
Published: August 2002

Ten model coatings, selected and obtained from a family of fluorinated resins synthesized by the reaction of perfluoroether oligomeric diols of different molecular weights with polyisocyanurates of hexamethylenediisocyanate (HDI) and isophoronediisocyanate (IPDI), were characterized with differential scanning calorimetry, mechanical testing, and electrochemical impedance spectroscopy measurements. The electrochemical and chemico‐physical measurements show that the glass‐transition temperature of the starting isocyanate trimers greatly influences the properties of the final urethane coatings; the IPDI trimer gives harder coatings with lower water permeabilities than the corresponding HDI‐based materials. Moreover, for each class of materials (from IPDI or HDI), the fluorine content plays a relevant role: the higher the fluorine percentage, the lower the water absorption into the coatings. Furthermore, the chain length of the polyols used for the synthesis of the prepolymers is a variable that exhibits great influence on the coating properties: coatings containing shorter perfluoropolyether segments show better barrier properties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 52–64, 2002
Fourier transform infrared study on the sorption of water to various kinds of polymer thin films
Authors: Ichikawa Ken , Mori Takayuki , Kitano Hiromi , Fukuda Mitsuhiro , Mochizuki Akira , Tanaka Masaru
Published: August 2002

The state of sorbed water and the sorbing processes of water to various polymer thin films were studied with Fourier transform infrared (FTIR) spectroscopy. To prepare the polymer films, we used poly(ethylene glycol)s of different molecular weights and various kinds of vinyl polymers, such as poly(2‐methoxyethyl acrylate). The OH stretching band of water sorbed in the films increased gradually on contact with water vapor at 50% relative humidity and leveled off. When OH stretching bands of water sorbed to polymer films were compared, the peak positions and profiles of water sorbed to the polymeric materials with the same hydrogen‐bonding site were similar. A hybrid density‐functional method supported the assignment of the peaks. Furthermore, the diffusion coefficient (D) of water vapor in the polymer films was estimated by time‐resolved measurements of the sorbed water at the very initial stage (0–830 s). It was clearly shown that the D values of water vapor in the polymer materials with a strong hydrogen‐bonding site were smaller than those in hydrophobic polymers. The usefulness of the FTIR technique to investigate water sorption to polymer materials was definitely demonstrated. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2175–2182, 2001
Thermal, mechanical, and morphological properties of novolac‐type phenolic resin blended with fullerenol polyurethane and linear polyurethane
Authors: Ma Chen‐Chi M. , Sung Shang‐Chin , Wang Feng‐Yih , Chiang Long Y. , Wang Lee Y. , Chiang Chin‐Lung
Published: August 2002

Fullerenol polyurethane (C60‐PU) and linear polyurethane (linear‐PU) modified phenolic resins were prepared in this study. Phenolic resin/C60‐PU and phenolic resin/linear‐PU blends show good miscibility as a result of the intermolecular hydrogen bonding existing between phenolic resin and PU modifiers. DSC and thermogravimetric analysis methods were used to study the thermal properties of phenolic resin blended with different types of PUs. The intermolecular hydrogen bonding that existed between phenolic resin and C60‐PU was investigated by Fourier transform infrared spectroscopy. The morphology and mechanical properties of phenolic resin/C60‐PU and phenolic resin/linear‐PU blends were also investigated. The char yield of the modified phenolic resins decreased with increasing PU modifier content. Significant improvement in the toughness of the modified phenolic resins was observed. The improvements of impact strength were 27.4% for the phenolic resin/linear‐PU system and 54.3% for the phenolic resin/C60‐PU system, respectively, both with 3 phr linear‐PU and C60‐PU content. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2436–2443, 2001