bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Algorithms for Creation of Linearly‐independent Decision Diagrams and their Mapping to Regular Layouts
Authors: Perkowski Marek , Falkowski Bogdan , Chrzanowska-Jeske Malgorzata , Drechsler Rolf
Published: August 2002

A new kind of a decision diagrams are presented: its nodes correspond to all types of nonsingular expansions for groups of input variables, in particular pairs. The diagrams are called the Linearly Independent (LI) Decision Diagrams (LI DDs). There are 840 nonsigular expansions for a pair of variables, thus 840 different types of nodes in the tree. Therefore, the number of nodes in such (exact) diagrams is usually much smaller than the number of nodes in the well‐known Kronecker diagrams (which have only single‐variable Shannon, Positive Davio, and Negative Davio expansions in nodes). It is usually much smaller than 1/3 of the number of nodes in Kronecker diagrams. Similarly to Kronecker diagrams, the LI Diagrams are a starting point to a synthesis of multilevel AND/OR/EXOR circuits with regular structures. Other advantages of LI diagrams include: they generalize the well‐known Pseudo‐Kronecker Functional Decision Diagrams, and can be used to optimize the new type of PLAs called LI PLAs. Importantly, while the known decision diagrams used AND/EXOR or AND/OR bases, the new diagrams are AND/OR/EXOR‐based. Thus, because of a larger design space, multi‐level structures of higher regularity can be created with them. This paper presents both new concepts and new efficient synthesis algorithms.
Word‐serial Architectures for Filtering and Variable Rate Decimation
Authors: Grayver Eugene , Daneshrad Babak
Published: August 2002

A new flexible architecture is proposed for word‐serial filtering and variable rate decimation/interpolation. The architecture is targeted for low power applications requiring medium to low data rate and is ideally suited for implementation on either an ASIC or an FPGA. It combines the small size and low power of an ASIC with the programmability and flexibility of a DSP. An efficient memory addressing scheme eliminates the need for power hungry shift registers and allows full reconfiguration. The decimation ratio, filter length and filter coefficients can all be changed in real time. The architecture takes advantage of coefficient symmetries in linear phase filters and in polyphase components.
A Fast Dynamic 64‐bit Comparator with Small Transistor Count
Authors: Wang Chua-Chin , Hsueh Ya-Hsin , Wu Hsin-Long , Wu Chih-Feng
Published: August 2002

In this paper, we propose a 64‐bit fast dynamic CMOS comparator with small transistor count. Major features of the proposed comparator are the rearrangement and re‐ordering of transistors in the evaluation block of a dynamic cell, and the insertion of a weak n feedback inverter, which helps the pull‐down operation to ground. The simulation results given by pre‐layout tools, e.g. HSPICE, and post‐layout tools, e.g. TimeMill, reveal that the delay is around 2.5 ns while the operating clock rate reaches 100 MHz. A physical chip is fabricated to verify the correctness of our design by using UMC (United Microelectronics Company) 0.5 μm (2P2M) technology.
Global cDNA Amplification Combined with Real-Time RT–PCR: Accurate Quantification of Multiple Human Potassium Channel Genes at the Single Cell Level
Authors: Al-Taher A. , Bashein A. , Nolan T. , Hollingsworth M. , G. Brady
Published: August 2002

We have developed a sensitive quantitative RT–PCR procedure suitable for the analysis of small samples, including single cells, and have used it to measure levels of potassium channel mRNAs in a panel of human tissues and small numbers of cells grown in culture. The method involves an initial global amplification of cDNA derived from all added polyadenylated mRNA followed by quantitative RT–PCR of individual genes using specific primers. In order to facilitate rapid and accurate processing of samples, we have adapted the approach to allow use ofTaqMan™real-time quantitative PCR. We demonstrate that the approach represents a major improvement over existing conventional and real-time quantitative PCR approaches, since it can be applied to samples equivalent to a single cell, is able to accurately measure expression levels equivalent to less than 1/100th copy/cell (one specific cDNA molecule present amongst108total cDNA molecules). Furthermore, since the initial step involves a global amplification of all expressed genes, a permanent cDNA archive is generated from each sample, which can be regenerated indefinitely for further expression analysis.
T‐γ large granular lymphocyte leukemia associated with amegakaryocytic thrombocytopenic purpura, Sjögren's syndrome, and polyglandular autoimmune syndrome type II, with subsequent development of pure red cell aplasia
Authors: Ergas David , Tsimanis Alexander , Shtalrid Mordechai , Duskin Chen , Berrebi Alain
Published: August 2002

We present a female patient with T‐γ LGL leukemia, who was followed for the last 20 years. Over these years she developed several autoimmune disorders, including Sjögren's syndrome, Hashimoto's thyroiditis, premature ovarian failure (compatible with type II autoimmune polyglandular syndrome), amegakaryocytic thrombocytopenic purpura, and finally pure red cell aplasia. PCR analysis confirmed rearrangement for TCR γ. This case emphasizes the complex association of LGL leukemia with autoimmune disorders. Am. J. Hematol. 69:132–134, 2002. © 2002 Wiley‐Liss, Inc.
Molecular characteristics of pediatric patients with sickle cell anemia and stroke
Authors: Sarnaik Sharada A. , Ballas Samir K.
Published: August 2002

Cerebrovascular accidents (CVA) are serious complications of sickle cell anemia (SS) in children. Factors that predispose children to this complication are not well established. In an effort to elucidate the risk factors associated with CVA in SS, we have determined the α‐globin genotype and the βS haplotype of children with this complication. Among 700 children with SS followed at Children's Hospital of Michigan, 41 (6%) are on chronic transfusions because of stroke due to cerebral infarction. The mean age of patients with CVA at the time of stroke was 5.6 ± 3.2 years (mean ± SD). The male/female ratio was 2/3. Only 8 of 41 patients (19.5%) had one α‐gene deletion, compared to the reported prevalence of 30% in African‐Americans. None of the patients had two α‐gene deletions, and two (5%) had five α‐genes. These findings are different than those in our adult patients with SS, where the prevalence of −α/−α and ααα/αα is 4% and <2%, respectively. Ten different βS‐haplotypes were detected in the patients studied. The majority of the patients (31%) were doubly heterozygous for the Ben/CAR haplotypes followed by Ben/Ben, Ben/Sen, and CAR/CAR haplotypes, respectively. The prevalence of these haplotypes, with the exception of the CAR/CAR haplotype, was higher in females than males. All the patients with CAR/CAR haplotype were males, had four α‐genes, and ranked third in prevalence. Three patients were heterozygous for the Cameron haplotype. The Cameron and atypical haplotypes were more prevalent than reported in patients with SS at large. The data suggest that CVA in children seems to occur more frequently in females and in patients with certain βS haplotype. α‐Gene deletion seems to offer a protective effect against this complication. Neonates with four or more α‐genes whose βS haplotype is Ben/CAR, atypical, or CAR/CAR seem to be at a higher risk for CAV than other patients. A prospective study on a larger group of patients with or without CVA may clarify this issue. Am. J. Hematol. 67:179–182, 2001. © 2001 Wiley‐Liss, Inc.
Nested case‐control analysis of high pesticide exposure events from the Agricultural Health Study
Authors: Alavanja Michael C. R. , Sprince Nancy L. , Oliver Eugene , Whitten Paul , Lynch Charles F. , Gillette Patricia P. , Logsden‐Sacket Nyla , Zwerling Craig
Published: August 2002

Background

A nested case‐control analysis of high pesticide exposure events (HPEEs) was conducted using the Iowa farmers enrolled in the Agricultural Health Study (AHS).

Methods

In the 12 months of the study, 36 of the 5,970 farmer applicators randomly chosen from the AHS cohort (six per 1,000 farmer applicators per year) met our definition of an HPEE, by reporting “an incident with fertilizers, weed killers, or other pesticides that caused an unusually high personal exposure” resulting in physical symptoms or a visit to a health care provider or hospital. Eligibility criteria were met by 25 HPEE cases and 603 randomly selected controls.

Results

Significant risk factors for an HPEE included: poor financial condition of the farm which limited the purchase of rollover protective structures OR = 4.6 (1.5–16.6), and having a high score on a risk acceptance scale OR = 3.8 (1.4–11.2). Other non‐significant factors were also identified.

Conclusions

The limited statistical power of this study necessitates replication of these analyses with a larger sample. Nonetheless, the observed elevated odds ratios of an HPEE provide hypotheses for future studies that may lead to preventive action. Am. J. Ind. Med. 39:557–563, 2001. © 2001 Wiley‐Liss, Inc.
The 5‐HT2A receptor gene 102T/C polymorphism is associated with suicidal behavior in depressed patients
Authors: Arias Bárbara , Gastó Cristobal , Catalán Rosa , Gutiérrez Blanca , Pintor Luis , Fañanás Lourdes
Published: August 2002

Several lines of evidence suggest that genetic factors constitute an important determinant of suicidal behavior. A significant association between the 5‐HT2A‐C allele and suicidality has recently been reported. The aim of this study was to investigate whether the proposed association between 5‐HT2A‐102T/C polymorphism and suicidality could be replicated in a larger and independent sample of Spanish patients with major depression. The 102T/C polymorphism of the 5‐HT2A receptor gene was analyzed in 159 patients with major depression (DSM‐IV criteria) and 164 unrelated and healthy controls using a case control design. All individuals were subjects of Spanish origin. Significant differences in allele (chi‐square = 4.13, df = 1, P = 0.04) and genotype (chi‐square = 6.19, df = 2, P = 0.04) distributions were found between non–suicide attempters and suicide attempters. Moreover, those patients carrying 5‐HT2A‐C allele had more than five times the risk for attempting suicide than noncarriers (OR = 5.50, 95% CI = 1.18–35.20, P = 0.01). Our results replicate the proposed association between 5HT2A‐C allele and suicidality in major depression. Moreover, no overall associations are detected when patients with major depression and controls are compared for 102T/C frequencies, suggesting that the increased risk for suicidality conferred by 5‐HT2A‐C allele is primarily associated with suicidal behavior and not with the diagnosis of major depression itself. © 2001 Wiley‐Liss, Inc.
Common mutations of ATP7B in Wilson disease patients from Hungary
Authors: Firneisz Gábor , Lakatos Péter L. , Szalay Ferenc , Polli Claudia , Glant Tibor T. , Ferenci Peter
Published: August 2002

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. The H1069Q mutation in exon 14 of ATP7B is far the most frequent in Wilson patients of European origin. Mutations in exon 8 and 15 are also common among the over 150 described mutations in the WD gene. The aim was to investigate the frequency of these common WD gene mutations in Hungarian patients. A total of 42 patients with WD from 39 Hungarian families were examined. The H1069Q mutation was assessed by a seminested polymerase chain reaction (PCR)‐based restriction fragment length polymorphism (RFLP) assay, while mutations in exons 8, 13, 15, and 18 of WD gene were identified by sequencing. In addition, haplotype analysis was performed using three common microsatellite markers (D13S314, D13S301, D13S316). The H1069Q mutation was found in 27 patients (64.3%). Nine patients were H1069Q homozygous. Eighteen patients were H1069Q compound heterozygous, two of them had H1069Q/P969Q and one patient H1069Q/3400delC genotype. In two of the 15 H1069Q‐negative patients a novel mutation in exon 13 (T977M) was detected. One H1069Q‐negative patient had a mutation in exon 8 (G710S). None of the studied mutations was detected in 12 WD patients. H1069Q‐positive patients from various European countries had the same haplotype pattern. The H1069Q point mutation is frequent in Hungarian patients with WD and appears to have originated from a single founder in Eastern Europe. In contrast, mutations in exons 8, 13, 15, and 18 are uncommon in Hungarian WD patients. © 2002 Wiley‐Liss, Inc.
Complete overlap of PHACE syndrome and sternal malformation—vascular dysplasia association
Authors: James Paul A. , McGaughran Julie
Published: August 2002

PHACE syndrome is the term applied to the association of posterior fossa brain abnormalities, hemangiomas, arterial anomalies in the cranial vasculature, coarctation of the aorta/cardiac defects, and eye abnormalities. An overlap with the sternal malformation/vascular dysplasia association has been described. We report an adult patient with complete manifestations of both conditions. As an adult she has demonstrated resolution of the hemangiomas and only mild intellectual difficulties.
Fine mapping supports previous linkage evidence for a bipolar disorder susceptibility locus on 13q32
Authors: Liu Chunyu , Badner Judith A. , Christian Susan L. , Guroff Juliet J. , Detera‐Wadleigh Sevilla D. , Gershon Elliot S.
Published: August 2002

A region between D13S71 and D13S274 on 13q32 showed linkage to bipolar disorder (BP) based on a genome scan using markers with an average spacing of ∼6 cM and an average heterozygosity of ∼60% [Detera‐Wadleigh et al., 1999: Proc Natl Acad Sci USA 96:5604–5609]. In an attempt to confirm this finding and achieve fine mapping of the susceptibility region, nine additional microsatellite markers with average heterozygosity of ∼86%, located between D13S71 and D13S274, were typed in the same sample. The strongest linkage evidence was detected by multipoint linkage analysis (ASPEX program) around D13S779–D13S225 with maximum LOD score of 3.25 under Affection Status Model II (ASM II; P = 0.0000546). Data from additional nine markers resulted in a decrease of the 95% confidence interval of the linkage region. Association analyses with GASSOC TDT and ASPEX/sib_tdt detect potential linkage disequilibrium with several markers, including D13S280 (ASPEX TDT P = 0.0033, ASM I). These data generated using a higher marker density within the proposed susceptibility region strengthen the validity of our previous findings and suggest a finer localization of the susceptibility gene(s) on 13q32. © 2001 Wiley‐Liss, Inc.
No association between CHRNA7 microsatellite markers and attention‐deficit hyperactivity disorder
Authors: Kent Lindsey , Green Elaine , Holmes Jane , Thapar Anita , Gill Michael , Hawi Ziarah , Fitzgerald Michael , Asherson Philip , Curran Sarah , Mills John , Payton Anthony , Craddock Nick
Published: August 2002

Attention‐deficit hyperactivity disorder (ADHD) is a highly heritable, common psychiatric disorder of childhood that probably involves several genes. There are several lines of evidence suggesting that the nicotinic system may be functionally significant in ADHD. First, nicotine promotes the release of dopamine and has been shown to improve attention in adults with ADHD, smokers, and nonsmokers. Second, ADHD is a significant risk factor for early initiation of cigarette smoking in children and maternal cigarette smoking appears to be a risk factor for ADHD. Finally, animal studies in rats and monkeys also suggest that nicotine may be involved in attentional systems and locomotor activity. The nicotinic system has previously been studied in schizophrenia where the neuronal nicotinic acetylcholine receptor α7 subunit gene (CHRNA7) has been implicated in decreased P50 inhibition and attentional disturbances in patients with schizophrenia and in many of their nonschizophrenic relatives. Three known microsatellite markers (D15S165, D15S1043, and D15S1360) near the nicotinic acetylcholine α7 receptor gene, CHRNA7, were studied in 206 ADHD parent‐proband trios of children aged 5–16 with ADHD according to DSM‐IV criteria. Children with known major medical or psychiatric conditions or mental retardation (IQ < 70) were excluded from the study. Markers D15S165 and D15S1360 were in linkage disequilibrium. The extended Transmission Disequilibrium Test analyses demonstrated no evidence that variation at the microsatellite markers D15S1360, D15S1043, and D15S165 influences susceptibility to ADHD. However, it remains possible that the CHRNA7 gene and other nicotinic system genes may be involved in conferring susceptibility to ADHD. © 2001 Wiley‐Liss, Inc.
Relationship between platelet‐activating factor concentration in rhesus monkey (Macaca mulatta) spermatozoa and sperm motility
Authors: Roudebush William E. , Gerald Melissa S. , Cano Jose A. , Lussier Isabelle D. , Westergaard Greg , Higley J. Dee
Published: August 2002

Platelet‐activating factor (PAF) is a potent signaling phospholipid that has been implicated in a number of biological activities. PAF concentration in primate spermatozoa has a positive correlation with fertility. While PAF is present in rhesus spermatozoa, there are no relational reports on its concentration and the cell’s motility. The study objective was to determine if PAF concentration in rhesus spermatozoa was correlated with motility indices (percent motility and forward progression). Semen was collected from sexually mature males and cell counts, and percent motilities and forward progressions were recorded prior to PAF measurement by radioimmunoassay. Spermatozoa‐derived PAF concentration ranged from a low of 0.9 picomoles/106 cells to a high of 13.0 picomoles/106 cells. The overall mean (±SEM) PAF concentration was 4.6 (±1.6) picomoles/106 spermatozoa. Regression analysis revealed a positive and significant relationship between PAF concentration in the spermatozoa and percent motility (R2 = 0.914; P < 0.01) as well as forward progression (R2 = 0.849; P < 0.05). A receiver‐operator characteristic curve and the calculation of the probability that a positive forward progression will be predicted indicated a cutoff limit of 1.5 picomoles/106 cells for PAF concentration in rhesus sperm. Rhesus monkey spermatozoa motility was significantly greater (P < 0.01) in the high‐PAF (≥2 picomoles/106 cells) group (31.0 ± 7.6) than in the low‐PAF (<2 picomoles/106 cells) group (6.8 ± 2.1). Rhesus monkey spermatozoa forward progression was significantly greater (P < 0.05) in the high‐PAF (≥2 picomoles/106 cells) group (3.0 ± 1.0) than in the low‐PAF (<2 picomoles/106 cells) group (0.7 ± 0.3). The data demonstrate that PAF concentration in rhesus spermatozoa has a significant relationship with percent motility and the cell’s forward progression. Determining PAF concentration in spermatozoa may be a significant predictor of fertility in the primate. Additional studies will elucidate the role of PAF in spermatozoa function and the significance PAF plays in primate fertility. Am. J. Primatol. 56:1–7, 2002. © 2002 Wiley‐Liss, Inc.
Extreme mtDNA homogeneity in continental Asian populations
Authors: Oota Hiroki , Kitano Takashi , Jin Feng , Yuasa Isao , Wang Li , Ueda Shintaroh , Saitou Naruya , Stoneking Mark
Published: August 2002

Mitochondrial DNA (mtDNA) variation in continental Asia has not been well‐studied. Here, we report mtDNA HV1 sequences for 84 Xi'an and 82 Changsha Han Chinese, 89 Honshu Japanese, and 35 Vietnamese. Comparison of these sequences with other Asian mtDNA sequences reveals high variability within populations, but extremely low differentiation among Asian populations. Correlations between genetic distance and geographic distance, based on mtDNA and Y chromosome variation, indicate a higher migration rate in females than in males. This may reflect patrilocality, as suggested previously, but another plausible hypothesis is that the demographic expansion associated with the spread of agriculture in Asia may be responsible for the extreme genetic homogeneity in Asia. Am J Phys Anthropol 118:146–153, 2002. © 2002 Wiley‐Liss, Inc.
Case of metastatic carcinoma from end of the 8th–Early 9th century Slovakia
Authors: Šefčáková Alena , Strouhal Eugen , Němečková Alena , Thurzo Milan , Staššíková‐Štukovská Danica
Published: August 2002

The first case of metastatic carcinoma ever detected in Slovakia comes from a Slavonic cemetery at Borovce, in the district of Piešt'any, which is dated from the end of the 8th to the middle of the 12th century AD. The disease afflicted a 50–60‐year‐old male, buried in a grave from the older phase of inhumation (8th–early 9th century AD). A number of osteolytic metastases were found in all bones of the skull and postcranial skeleton except for the forearms, hands, lower legs, and feet. They were studied macroscopically by standard X‐rays, and by scanning electron microscopy and laser scanning confocal microscopy. Analogous finds from Central European countries were also obtained. They are discussed in relation to their chronology, which shows a tendency of increasing occurrence culminating in the Middle Ages. Some demographic and paleopathological characteristics of the burials in the Borovce cemetery are also provided. Am J Phys Anthropol 116:216–229, 2001. © 2001 Wiley‐Liss, Inc.
Environmental enrichment slows disease progression in R6/2 Huntington's disease mice
Authors: Hockly Emma , Cordery Patricia M. , Woodman Benjamin , Mahal Amarbirpal , Van Dellen Anton , Blakemore Colin , Lewis Cathryn M. , Hannan Anthony J. , Bates Gillian P.
Published: August 2002

Huntington's disease is a genetic disorder that causes motor dysfunction, personality changes, dementia, and premature death. There is currently no effective therapy. Several transgenic models of Huntington's disease are available, the most widely used of which is the R6/2 mouse, because of its rapid disease progression. Environmental enrichment alters gene expression in the normal mouse brain, and modulates the course of several neurological disorders. Environmentally enriched mice may actually mimic human disease more accurately. We found that even limited environmental enrichment slows decline in RotaRod performance in R6/2 mice, despite rapid disease progression, whereas in normal littermates, maximal enrichment was required to induce a marked improvement in behavioral tests. Enrichment also delayed the loss of peristriatal cerebral volume in R6/2 brains. These results could provide the basis for a rational approach to ameliorate the effects of Huntington's disease.
Childhood cerebellar hemangioblastoma does not predict germline or somatic mutations in the von Hippel‐Lindau tumor suppressor gene
Authors: Fisher Paul Graham , Tontiplaphol Art , Pearlman Eric M. , Duffner Patricia K. , Hyder Douglas J. , Stolle Catherine A. , Vortmeyer Alexander O. , Zhuang Zhengping
Published: August 2002

Tumor suppressor gene “knockout” models would predict that children who present with hemangioblastoma are likely to harbor germline mutation of the von Hippel‐Lindau gene. We screened 6 pediatric patients with cerebellar hemangioblastoma for germline or somatic mutations of the von Hippel‐Landau gene. Two had prior clinical manifestations of von Hippel‐Lindau disease and, as expected, had germline von Hippel‐Lindau gene mutations. Four children with solitary hemangioblastoma did not have a detectable germline deletion, rearrangement, or point mutation in their von Hippel‐Landau gene, and tumor specimens in 3 of these 4 showed no somatic von Hippel‐Landau allelic loss. Solitary cerebellar hemangioblastoma in children does not predict a germline or somatic mutation in the von Hippel‐Landau tumor suppressor gene. The tumorigenesis of hemangioblastoma in younger patients may differ from that in adults, and may involve a molecular process unrelated to the von Hippel‐Lindau tumor suppressor pathway.
Adaptive functional changes in the cerebral cortex of patients with nondisabling multiple sclerosis correlate with the extent of brain structural damage
Authors: Rocca Maria A. , Falini Andrea , Colombo Bruno , Scotti Giuseppe , Comi Giancarlo , Filippi Massimo
Published: August 2002

In multiple sclerosis, the mechanisms underlying the accumulation of disability are poorly understood. Recently, it has been suggested that adaptive cortical changes may limit the clinical impact of multiple sclerosis injury. In this study, functional magnetic resonance imaging and a general search method were used to assess patterns of brain activation associated with a simple motor task in 14 right‐handed, nondisabled relapsing‐remitting multiple sclerosis patients that were compared to those from 15 right‐handed, sex‐ and age‐matched healthy volunteers. Also investigated were the extent to which the functional magnetic resonance imaging changes correlated with T2 lesion volume and severity of multiple sclerosis pathology in lesions and normal‐appearing brain tissue, measured using magnetisation transfer and diffusion tensor magnetic resonance imaging. Compared to controls, multiple sclerosis patients showed increased activation in the contralateral primary sensorimotor cortex, bilaterally in the supplementary motor area, bilaterally in the cingulate motor area, in the contralateral ascending bank of the sylvian fissure, and in the contralateral intraparietal sulcus. T2 lesion volume was correlated with relative activation in the ipsilateral supplementary motor area, and in the ipsilateral and contralateral cingulate motor area. Average lesion magnetisaiton transfer ratio and average lesion water diffusivity were correlated with relative activation in the contralateral sensorimotor cortex. Average lesion magnetisation transfer ratio was also correlated with relative activation in the ipsilateral cingulate motor area. Average water diffusivity and peak height of the normal‐appearing brain tissue diffusivity histogram were both correlated with relative activation in the contralateral intraparietal sulcus. This study shows that cortical activation occurs over a rather distributed sensorimotor network in nondisabled relapsing‐remitting multiple sclerosis patients. It also suggests that increased recruitment of this cortical network contributes to the limitation of the functional impact of white matter multiple sclerosis injury.
Neuronal activity in the globus pallidus in chorea caused by striatal lacunar infarction
Authors: Hashimoto Takao , Morita Hiroshi , Tada Tsuyoshi , Maruyama Tetsuhiro , Yamada Yuzo , Ikeda Shu‐Ichi
Published: August 2002

Pallidotomy was performed in a patient with hemichorea caused by lacunar infarction in the striatum. Chorea in the lower limb was reduced after a neurosurgical lesion in the medial portion of the sensorimotor territory of the internal segment of the globus pallidus, and chorea in the upper limb disappeared after an additional lesion in the lateral portion of that same area. Intraoperative neuronal recording revealed that mean firing rates were low, and that firing was irregular in the globus pallidus compared with off‐state parkinsonian patients. These results suggest that chorea with striatal infarction is driven by phasic neuronal activity with a low firing rate in the globus pallidus and that the neural pathway of chorea has a functional somatotopical organization in the globus pallidus.
Improved spinnerette design for extrusion of polymeric large internal diameter hollow fiber membranes
Authors: Sonnenschein Mark F.
Published: August 2002

Spinnerettes for extrusion of large (∼ 1 mm) internal diameter (i.d.) hollow fiber membranes must possess certain features to extrude fibers with the proper tensile and geometrical properties. Spinnerette designs that properly extrude small i.d. (< 200 μm) hollow fibers will produce large i.d. hollow fibers with low burst strengths because of poor flow patterns and insufficient time in the spinnerette to knit a strong seam interface. In this report, an alternative design is offered that provides much better fiber properties without creating high pressure drops or shear stresses at the spinnerette wall that would normally result in melt fracture. The equations that guide the presented spinnerette design are provided and the suggested design is successfully guided by the results. The new spinnerette design also has the feature of allowing rapid change of hollow fiber wall thickness by making the core fluid pin replaceable. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2157–2163, 2002
Interfacial tension of polycaprolactone/polystyrene blends by the imbedded fiber retraction method
Authors: Biresaw G. , Carriere C. J.
Published: August 2002

Polycaprolactone (PCL) is a biodegradable polyester that is widely used in blends with synthetic and natural polymers for various applications. PCL is blended with biopolymers such as starch to improve its wet mechanical properties without impairing the biodegradability and other useful properties of starch. In spite of its importance, little is known about the interfacial tension of PCL blends. Indirect estimates of the room‐temperature interfacial tension of PCL blends using wettability methods have been reported. However, direct measurements of the interfacial tension of PCL blends have not been achieved until now, mainly because of the unsuitability of existing equilibrium methods for measuring the interfacial tension of high viscosity blends. We have measured the interfacial tension of PCL/PS blends using the imbedded fiber retraction (IFR) method. The IFR is a dynamic method that allows for the measurement of interfacial tension of high viscosity polymer blends in a relatively short period of time. The interfacial tension of PCL/PS blends was measured from 160 to 200°C. In this temperature range, the interfacial tension of PCL/PS blends is independent of temperature and has a value of 7.6 ± 1.8 dyn/cm. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3145–3151, 2002; DOI 10.1002/app.10178
Impact modification of polyacetal by thermoplastic elastomer polyurethane
Authors: Mehrabzadeh M. , Rezaie D.
Published: August 2002

The main goal of this study was impact modification of polyacetal [polyoxymethylene (POM)] with thermoplastic elastomer polyurethane (TPU). We modified the impact strength of POM 10‐fold. The mechanical properties, thermal behavior, and morphology of POM/TPU blends consisting of 5 to 50% of TPU were studied. It was found that the best impact modification of the blends was at 15% concentration of TPU and the maximum elongation at break was at 30% concentration of TPU. The impact strength of POM/TPU blends can be improved by using diphenylmethane diisocyanate (MDI) as compatibilizer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2573–2582, 2002
Improved adhesion property and electromagnetic interference shielding effectiveness of electroless Cu‐plated layer on poly(ethylene terephthalate) by plasma treatment
Authors: Oh Kyung Wha , Kim Dong Jun , Kim Seong Hun
Published: August 2002

To develop high‐quality electromagnetic interference (EMI) shielding materials, the effect of plasma pretreatment with various gases prior to Cu plating was investigated. Plasma treatment increased the surface roughness in the decreasing order of Ar > O2 > NH3, but adhesion of the Cu layer on poly(ethylene terephthalate) (PET) film increased in the following order of O2 < Ar < NH3, indicating that the appropriate surface roughness and introduction of an affinitive functional group to Pd on the surface of the PET film were key factors for improving adhesion of the Cu layer. As investigated by XPS analysis, plasma treatment with NH3 produced N atoms on the PET film, which enhances the chemisorption of Pd2+ on PET film, resulting in improved adhesion and shielding effectiveness of the Cu layer deposited on the Pd‐catalyzed surface, because of the high affinity of Pd2+ for nitrogen. Comparatively, O2 plasma treatment allowed the chemisorption of more Sn2+ than of Pd2+ due to a lack in the affinity of Pd2+ for oxygen, resulting in the lowest Pd3d/Sn3d ratio; thereby, the lowest EMI–shielding effectiveness (SE) value was obtained. In addition, fairly low adhesion was obtained with Ar plasma‐treated PET, even though the PET surface was significantly etched with Ar plasma, due to introduced oxygen groups on the PET surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1369–1379, 2002; DOI 10.1002/app.10272
Morphological prediction and its application to the synthesis of polyacrylate/polysiloxane core/shell latex particles
Authors: Kan Cheng You , Kong Xiang Zheng , Yuan Qing , Liu De Shan
Published: August 2002

A theoretical analysis and a morphological prediction of polyacrylate (PA)/polysiloxane (PSi) latex particles with core/shell morphologies were first conducted based on interfacial tensions and relative volumes of the two polymers in the latex system. The results indicated that the normal core/shell morphology particles (PSi/PA), with hydrophobic polysiloxane as the core and with hydrophilic polyacrylate as the shell, can be easily formed. Although the inverted core/shell morphology particles (PA/PSi) with polyacrylate as the core could not be formed in most cases, even if the fraction volume of polysiloxane was larger than 0.872, which is the smallest value of forming a PA/PSi particle, the PSi/PA particles were unavoidably formed simultaneously with PA/PSi particle formation. The synthesis of PA/PSi particles containing equal amounts of polyacrylate and polysiloxane was then carried out using seeded emulsion polymerization. Before the cyclosiloxane cationic polymerization, 3‐methacryloyloxypropyl trimethoxysilane (MATS) was introduced into the polyacrylate seed latex to form an intermediate layer and chemical bonds between the core and the shell polymers. The characterization by transmission electron microscopy (TEM) demonstrated that the perfect PA/PSi core/shell particle is successfully synthesized when both the core and the shell polymers are crosslinked. The experiments showed that both the hardness and water adsorption ratio characteristics of latex films of the PA/PSi particles are in good agreement with those of the polysiloxane film. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2251–2258, 2001
An investigation of water crosslinking reactions of silane‐grafted LDPE
Authors: Shieh Yeong‐Tarng , Liau Jia‐Sheng , Chen Tzung‐Kai
Published: August 2002

Factors—including time, temperature, morphology, and thickness of sample, the extent of silane grafting, and water concentration—that affect the rate and degree of water crosslinking reactions of the silane‐grafted LDPE are investigated. The gel content of the water‐crosslinked sample increases with increasing time, temperature, and water concentration, but with decreasing content of the crystalline component in the sample and thickness of the sample. The relationship between the gel content and the crosslinking time is dependent on thickness and morphology of the sample, and the extent of silane grafting in the sample. The crosslinking rates and the resultant gel content are inversely proportional to the content of crystalline component of the sample, suggesting that the crosslinking reactions occur mainly in the amorphous domain of the sample. For those samples with high resultant gel contents, the crystallizations of the samples are significantly enhanced by crosslinking when the gel contents are higher than about 40%, leading to a dual relationship between the gel contents of the samples and the crosslinking times. For low temperatures, the rate‐determining step of the crosslinking reactions is the diffusion of water, rather than the hydrolysis and the subsequent condensation reactions of the silyl trimethoxy groups. For high temperatures and high extents of silane grafting in the samples, however, the chemical reactions dominate the crosslinking process. The overall activation energy of the crosslinking reactions is dependent on thickness of the sample. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 186–196, 2001
Study of the kinetics, mass transfer, and particle morphology in the production of high‐impact polypropylene
Authors: Kittilsen P. , McKenna T. F.
Published: August 2002

A sequence of experimental steps was perfected to produce high‐impact modified polypropylene (PP), and to study the influence of particle morphology and rubber content on the reaction kinetics, especially in terms of mass transfer limitations. It was found that after a critical copolymer content at approximately 40% (with respect to total weight), it was impossible to obtain high reaction rates. This is thought to be the result of a fundamental change in particle morphology attributed to the presence of a soft EPR copolymer phase in the micropores. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1047–1060, 2001
Examination of selected synthesis and room‐temperature storage parameters for wood adhesive‐type urea–formaldehyde resins by 13C‐NMR spectroscopy. IV
Authors: Kim Moon G. , Wan Hui , No Byung Y. , Nieh World L.
Published: August 2002

Typical particleboard wood‐adhesive urea–formaldehyde (UF) resins, synthesized with formaldehyde/first urea (F/U1) mol ratios of 1.80, 2.10, and 2.40 and the second urea added to an overall F/U ratio of 1.15, in weak alkaline pH, were allowed to stand at room temperature over a period of 50 days. 13C‐NMR of time samples taken over the storage period showed gradual migration of hydroxymethyl groups from the polymeric first‐urea components to the monomeric second‐urea components and also an advancing degree of polymerization of resins by forming methylene and methylene ether groups involving the second urea. These phenomena that varied with the F/U1 mol ratios used in the resin syntheses due to the varying polymer branching structures resulted in the first step of resin synthesis. Varying viscosity decreases and increases of the resins also occurred. Due to these chemical and physical changes, the particleboards that bonded with the sampled resins showed varying bond strength and formaldehyde‐emission values, indicating process optimizations possible to improve bonding and formaldehyde‐emission performances. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1155–1169, 2001
Correlation between molecular structure, free volume, and physical properties of a wide range of main chain thermotropic liquid crystalline polymers
Authors: Hsieh Tsung‐Tang , Tiu Carlos , Simon George P.
Published: August 2002

Physical phenomena such as glass transition temperatures, melting points, and relaxational behavior have been determined for a wide range of thermotropic liquid crystalline polymers (TLCPs) and polycarbonate (PC). Damping intensities of rigid TLCPs during glass transition are greater than those of semirigid and semiflexible TLCPs. Positron annihilation lifetime spectroscopy was also employed to evaluate free volume parameters of polymers. In general, the positron annihilation lifetime spectroscopy (PALS) free volume parameters show that all TLCPs have much smaller, fewer free volume sites compared with PC. Correlations were found between PALS free volume parameters and glass transition temperature, dynamic mechanical damping strength, and bulk density where greater free volume parameters corresponded to higher glass transition temperatures, greater damping strength, and lower density. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2252–2267, 2001
Dynamics and evolution of structure in fiber extrusion
Authors: Shimizu Jiro , Kikutani Takeshi
Published: August 2002

This paper gives a review of scientific advances in the understanding of the mechanism of fiber structure development in the high‐speed melt spinning process. Research in this field has been active since the late 1970s. Particular attention is paid to the molecular orientation and orientation‐induced crystallization occurring in the high‐speed spinning process of poly(ethylene terephthalate), polyamides, and some other types of polymers. Characteristics of crystalline morphology developed in the spin line and evolution of structural variation in the cross‐section of the fiber are also discussed. On‐line measurement of the spin line revealed that fiber structure development is accompanied with neck‐like deformation. Detailed behavior of the neck‐like deformation such as diameter profile, necking temperature, and necking draw ratio are presented, and the relation between the neck‐like deformation and the structure development is also discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 539–558, 2002
The conservation of unionid mussels in Louisiana rivers: diversity, assemblage composition and substrate use
Authors: Brown Kenneth M. , Banks Patrick D.
Published: August 2002

1. To aid in their conservation, unionid mussel assemblages were surveyed in three relatively unstudied rivers in south‐eastern Louisiana.

2. Although total species richness varied among rivers, species diversity (as estimated both by Shannon‐Weaver H′ and rank‐abundance curves) was fairly similar.

3. Assemblage composition varied among the rivers, with the West Pearl River having the most dissimilar group of species. The endangered inflated heel splitter, Potamilus inflatus, was found only in the lower Amite River.

4. The most common species had size distributions skewed towards larger individuals, but small individuals were collected (including the inflated heel splitter), indicating successful recruitment.

5. Mussels were more common in silt than in sand or gravel, perhaps because fine sediments are more stable through time in these river systems.

6. The greatest threat to these assemblages is gravel mining in the upper reaches of the rivers. At the present time only rivers with endangered species, or that have been declared scenic rivers, have any protection from gravel mining. Copyright © 2001 John Wiley & Sons, Ltd.
Extracting macroscopic information from Web links
Authors: Thelwall Mike
Published: August 2002

Much has been written about the potential and pitfalls of macroscopic Web‐based link analysis, yet there have been no studies that have provided clear statistical evidence that any of the proposed calculations can produce results over large areas of the Web that correlate with phenomena external to the Internet. This article attempts to provide such evidence through an evaluation of Ingwersen's (1998) proposed external Web Impact Factor (WIF) for the original use of the Web: the interlinking of academic research. In particular, it studies the case of the relationship between academic hyperlinks and research activity for universities in Britain, a country chosen for its variety of institutions and the existence of an official government rating exercise for research. After reviewing the numerous reasons why link counts may be unreliable, it demonstrates that four different WIFs do, in fact, correlate with the conventional academic research measures. The WIF delivering the greatest correlation with research rankings was the ratio of Web pages with links pointing at research‐based pages to faculty numbers. The scarcity of links to electronic academic papers in the data set suggests that, in contrast to citation analysis, this WIF is measuring the reputations of universities and their scholars, rather than the quality of their publications.
Intuitions about declining marginal utility
Authors: Greene Joshua , Baron Jonathan
Published: August 2002

In two studies, subjects judged the desirability of distributions of life expectancy or money. Their judgments showed declining marginal utility. That is, they were less sensitive to changes at the high end of each scale. Subjects also made utility ratings of the outcomes of individuals. And they made ratings of the distributions when these were described in terms of utility ratings rather than goods (years or dollars). The judgments of utility ratings showed equivalent declining marginal utility, even though they were based on utilities that themselves declined marginally. People extend their intuition about declining marginal utility to utility itself, as if utility had utility that declined marginally. In one experiment, a similar result was found with gambles: people are risk averse for utility as well as for money. We argue that this is an overextension of a reasonable heuristic and that this heuristic may account for one classic objection to utilitarian distributions. Copyright © 2001 John Wiley & Sons, Ltd.
Relative contribution of residential and occupational magnetic field exposure over twenty‐four hours among people living close to and far from a power line
Authors: Forssén Ulla M. , Ahlbom Anders , Feychting Maria
Published: August 2002

This study sought to estimate the relative contribution of exposure to 50 Hz magnetic fields experienced at home, at work/school, or elsewhere to the total exposure over 24 hr. Personal exposure meters were carried by 97 adults and children in the Stockholm area. About half of the subjects lived close (< 50 m) to a transmission line and half far (> 100 m) away. Spot measurements and calculations for the residential exposure were also made. For subjects living < 50 m from the line, the exposure at home contributed about 80% of the total magnetic field exposure, measured in μT‐hours. Adults living far away experienced only 38% of the total exposure at home, but children still received 55%. Subjects with low time‐weighted average (TWA) exposure both at home and at work spent 84% of their time in fields < 0.1 μT, and those with high TWA at both locations spent 69% of their time in fields ≥ 0.2 μT. This contrast was diluted if only exposure at one location was considered. For spot measurements and calculations of the residential exposure, both sensitivity and specificity was good. However, the intermediate field exposure category (0.1–0.19 μT) showed poor correlation to the 24 hr personal measurements. Bioelectromagnetics 23:239–244, 2002. © 2002 Wiley‐Liss, Inc.
Experiments on the effects of a continuous 16.7 Hz magnetic field on melatonin secretion, core body temperature, and heart rates in humans
Authors: Griefahn Barbara , Künemund Christa , Blaszkewicz Meinolf , Golka Klaus , Mehnert Peter , Degen Gisela
Published: August 2002

The present study investigated the hypothesis that a strong extremely low frequency magnetic field partially suppresses the synthesis of melatonin and subsequently elevates the core body temperature. Seven healthy young men (16–22 years) took part in a control and in an exposure session. Three men experienced first the control and then the exposure session, four men experienced the sessions in reverse order. Control sessions were performed as constant routines, where the participants spent 24 hour periods continuously in bed while air temperature was 18°C, illumination less than 30 lux, and the sound pressure level 50 dBA. The exposure sessions differed from that protocol only between 6 pm and 2 am when a strong extremely low frequency magnetic field was continuously applied (16.7 Hz, 0.2 mT). Assuming that the participants were unable to perceive the field consciously, they were blind against the actual condition. Salivary melatonin levels were determined hourly; body core temperatures and heart rates were registered continuously throughout. Neither of these parameters revealed alterations that can be related to the influence of the magnetic field. The present results, taken together with other investigations using that particular field, lead to the hypothesis that the effects most likely, occur, only after repetitive exposures to intermittent fields. Bioelectromagnetics 22:581–588, 2001. © 2001 Wiley‐Liss, Inc.