bluuebunny/crossref_metadata_2025 huggingface dataset:
Neutralization Profiles of Newly Transmitted Human Immunodeficiency Virus Type 1 by Monoclonal Antibodies 2G12, 2F5, and 4E10
Authors: Mehandru Saurabh , Wrin Terri , Galovich Justin , Stiegler Gabriela , Vcelar Brigitta , Hurley Arlene , Hogan Christine , Vasan Sandhya , Katinger Hermann , Petropoulos Christos J. , Markowitz Martin
Published: November 2004

As the AIDS epidemic continues unabated, the development of a human immunodeficiency virus (HIV) vaccine is critical. Ideally, an effective vaccine should elicit cell-mediated and neutralizing humoral immune responses. We have determined the in vitro susceptibility profile of sexually transmitted viruses from 91 patients with acute and early HIV-1 infection to three monoclonal antibodies, 2G12, 2F5, and 4E10. Using a recombinant virus assay to measure neutralization, we found all transmitted viruses were neutralized by 4E10, 80% were neutralized by 2F5, and only 37% were neutralized by 2G12. We propose that the induction of 4E10-like antibodies should be a priority in designing immunogens to prevent HIV-1 infection.
Association of DC-SIGN Promoter Polymorphism with Increased Risk for Parenteral, but Not Mucosal, Acquisition of Human Immunodeficiency Virus Type 1 Infection
Authors: Martin Maureen P. , Lederman Michael M. , Hutcheson Holli B. , Goedert James J. , Nelson George W. , van Kooyk Yvette , Detels Roger , Buchbinder Susan , Hoots Keith , Vlahov David , O'Brien Stephen J. , Carrington Mary
Published: November 2004

There is considerable debate about the fundamental mechanisms that underlie and restrict acquisition of human immunodeficiency virus type 1 (HIV-1) infection. In light of recent studies demonstrating the ability of C type lectins to facilitate infection with HIV-1, we explored the potential relationship between polymorphisms in the
DC-SIGN
promoter and risk for acquisition of HIV-1 according to route of infection. Using samples obtained from 1,611 European-American participants at risk for parenteral (
n
= 713) or mucosal (
n
= 898) infection, we identified single-nucleotide polymorphisms in the
DC-SIGN
promoter using single-strand conformation polymorphism. Individuals at risk for parenterally acquired infection who had −336C were more susceptible to infection than were persons with −336T (odds ratio = 1.87,
P
= 0.001). This association was not observed in those at risk for mucosally acquired infection. A potential role for
DC-SIGN
specific to systemic acquisition and dissemination of infection is suggested.
Sensory level electrical muscle stimulation: effect on markers of muscle injury
Authors: McLoughlin T J , Snyder A R , Brolinson P G , Pizza F X
Published: November 2004

Background:Monophasic high voltage stimulation (MHVS) is widely prescribed for the treatment of inflammation associated with muscle injury. However, limited scientific evidence exists to support its purported benefits in humans.

Objective:To examine the efficacy of early initiation of MHVS treatment after muscle injury.

Methods:In a randomised, cross over design, 14 men performed repetitive eccentric contractions of the elbow flexor muscles followed by either MHVS or control treatment. MHVS treatments were applied five minutes and 3, 6, 24, 48, 72, 96, and 120 hours after eccentric contractions.

Results:MHVS resulted in a significant reduction (p<0.05) in delayed onset muscle soreness 24 hours after eccentric exercise compared with controls. Elbow extension was significantly increased immediately after administration of MHVS compared with controls. No significant differences were observed between MHVS treatment and controls for maximal isometric strength, flexed arm angle, or arm volume.

Conclusions:Early and frequent application of MHVS may provide transient relief from delayed onset muscle soreness and short term improvements in range of motion after injurious exercise. However, MHVS treatment may not enhance recovery after muscle injury because of lack of improvements in strength and active range of motion.
Unusual cause of wrist pain in a golfer: Figure 1
Authors: McHardy A J , Pollard H P
Published: November 2004

Wrist injury is common in golfers and normally occurs at the impact of the club with the ball. The unusual case is reported of a low handicap golfer with wrist pain aggravated by the putting stroke. The condition was resolved with treatment. The likely mechanism for the injury is discussed.
Endurance exercise and the production of growth hormone and haematopoietic factors in patients with anaemia
Authors: Dimeo F , Knauf W , Geilhaupt D , Böning D
Published: November 2004

Background:Physical activity has been shown to stimulate haematopoiesis in patients with anaemia due to chronic renal failure or haematological malignancies.

Objective:To evaluate the effect of moderate exercise on the production of haematopoietically active factors.

Methods:Ten patients (four men and six women, mean (SD) age 51 (10) years) with a haemoglobin concentration under 130 g/l (men) or 120 g/l (women) carried out five three minute exercise bouts at an intensity of 80% of the maximal heart rate, corresponding to a lactate concentration of 3 (0.5) mmol/l. Patients rested for three minutes between bouts. The concentrations of interleukin 6, stem cell factor, granulocyte-monocyte colony stimulating factor, granulocyte colony stimulating factor, erythropoietin, and growth hormone (GH) were evaluated before and in the eight hours after exercise.

Results:GH had risen significantly 15 minutes after exercise (1.1 (1.3)v2.7 (2.8) ng/ml; p<0.05). No change in the concentration of the other cytokines and growth factors was observed in the eight hours after exercise.

Conclusions:In patients with anaemia, submaximal exercise does not affect the concentration of haematopoietically active cytokines. However, it leads to an increased concentration of GH. This may be responsible for the improved haematopoiesis observed after an exercise programme in patients with chronic diseases.
A simple multistage field test for the prediction of anaerobic capacity in female games players
Authors: Cooper S-M , Baker J S , Eaton Z E , Matthews N
Published: November 2004

Objective:To establish the validity of a 15 m multistage shuttle run test (MSRT) as a predictor of anaerobic capacity (expressed as mean power output (MPO) from the 30 second Wingate anaerobic test (WAnT)) in female university standard games players.

Methods:Data came from three phases using a total of 72 players (mean (SD) age 20.3 (1.5) years, body mass 64.9 (8.8) kg, and stature 1.67 (0.04) m). The repeatability of the MSRT was assessed in phase 1 by applying 95% limits of agreement (LoA) to the test and retest results from a random sample of 20 players. In phase 2, linear relations between MPO and performance on the MSRT were investigated in a random sample of 36 players. As a result, a calibration model (Y  =  a + bX) was developed and cross validated in phase 3, in which the remaining 36 players performed both the WAnT and the MSRT. Time (seconds) to volitional exhaustion/disqualification from the MSRT was substituted into the calibration model from which MPO was predicted. The agreement between MPO predicted and MPO measured from the WAnT was quantified using LoA.

Results:Insignificant bias between repeat applications of the MSRT (meandiff(SDdiff)  =  1.0 (3.5) seconds (4 (14) m),t =  1.23, p  =  0.230) was found from phase 1. Data were homoscedastic (r =  0.061, p  =  0.799) with LoA ± 6.9 seconds (± 27 m). In phase 2 the strongest correlation was between MPO (W/kg0.67) and time to volitional exhaustion/disqualification on the MSRT;r =  0.715 (r2 =  51.1%, p  =  0.0005). As a result, the calibration model developed was: MPO (W/kg0.67)  =  12.5 + (0.2 × time (seconds)) with a standard error of prediction of 2.1 W/kg0.67. The cross validation in phase 3 showed insignificant bias between measured and predicted MPO (meandiff(SDdiff)  =  0.3 (2.8) W/kg0.67,t =  0.75, p  =  0.460). Data were homoscedastic (r =  0.05, p  =  0.774) with LoA ± 5.5 W/kg0.67.

Conclusions:The MSRT requires minimal equipment and training of assessors, and it is easy to perform. In the population studied, it provides scores that are repeatable, and anaerobic capacity (MPO) can be successfully predicted from its performance. It would seem therefore to be a useful field based test for use by female games players, their coaches, and support scientists.
Indeterminate colitis
Authors: Guindi M , Riddell R H
Published: November 2004

Indeterminate colitis (IC) originally referred to those 10–15% of cases of inflammatory bowel disease (IBD) in which there was difficulty distinguishing between ulcerative colitis (UC) and Crohn’s disease (CD) in the colectomy specimen. However, IC is increasingly used when a definitive diagnosis of UC or CD cannot be made at colonoscopy, in colonic biopsies or at colectomy. The diagnostic difficulties may explain the variably reported prevalence of IC. Clinically, most patients with IC evolve to a definite diagnosis of UC or CD on follow up. The role of ancillary tests in the distinction of UC from CD is reviewed. The low sensitivity of serological markers limits their usefulness. Other tests include upper endoscopy and magnetic resonance imaging. The definition of IC may not be a purely histological one derived from resected specimens, but rather a clinicopathological one. This review offers some personal observations and viewpoints, and proposes an approach to some of the relatively more esoteric combinations of findings.
Sialometaplasia arising in the ectopic salivary gland ductal inclusions of multiple intraparotid lymph nodes
Authors: Sarioğlu S , Pabuççuoğlu U , Ecevit C , Ceryan K , Paksoy S , Ada E
Published: November 2004

Sialometaplasia, squamous metaplasia of salivary gland lobules, is a benign condition occasionally presenting with lesions clinically simulating malignancy. “Necrotising sialometaplasia”, recognised by lobular infarction, necrosis, and simultaneous squamous metaplasia of ducts and acini is a well known condition. There are only a few reports of the “proliferative type of sialometaplasia”, which is recognised by a more mature morphology of larger and more irregular metaplastic nests, lacking necrosis. This report describes a unique case of “proliferative sialometaplasia of multiple intraparotid lymph nodes” occurring in a 55 year old woman, presenting with multiple parotid lumps. This interesting case points to the importance of intraparotid lymph nodes as sites for multiple lesions of the parotid region.
nm23-H1 expression and loss of heterozygosity in colon adenocarcinoma
Authors: Kapitanović S , Čačev T , Berković M , Popović-Hadžija M , Radošević S , Seiwerth S , Spaventi Š , Pavelić K , Spaventi R
Published: November 2004

Background:The discovery that genetic alterations in oncogenes and tumour suppressor genes accompany tumour formation in many human tumours has encouraged the search for genes that promote or suppress tumour spread and metastasis; nm23 is a promising candidate for a metastasis suppressing gene.

Aims:To evaluate whether expression of nm23-H1 protein or loss of heterozygosity (LOH) of the nm23-H1 gene is associated with colon cancer progression.

Materials/Methods:Paraffin wax embedded tissue sections were analysed immunohistochemically. DNA isolated from normal and tumour tissue was used for LOH analysis using a variable nucleotide tandem repeat (VNTR) marker located in the untranslated 5′ region of the nm23-H1 gene. RNA isolated from tumour and normal tissue was used for “real time” RT-PCR.

Results:Of 102 adenocarcinomas examined, 58.8% stained weakly for nm23-H1 protein. There was a negative correlation between nm23-H1 positivity and tumour histological grade. In VNTR analysis, 70.2% of patients were informative and 27.4% of tumours had nm23-H1 LOH. There was a positive correlation between nm23-H1 LOH and both tumour histological grade and Dukes’s stage. Expression of nm23-H1 mRNA was increased in 22 of 30 colon tumours compared with normal tissue. No significant correlation was found between nm23-H1 mRNA expression and histological grade or Dukes’s stage of tumours.

Conclusions:These findings suggest that nm23-H1 protein expression in early stages may have a role in suppressing metastasis in sporadic colon cancer, whereas at a later stage both reduced nm23-H1 protein expression and LOH of the nm23-H1 gene may play role in colon cancer progression and metastasis.
Identification of helicobacter species in human liver samples from patients with primary hepatocellular carcinoma
Authors: Huang Y , Fan X-G , Wang Z-M , Zhou J-H , Tian X-F , Li N
Published: November 2004

Aims:Several studies have shown the presence of helicobacter species in the human biliary tract and in the intestinal tract of animals. Experimental infection byHelicobacter hepaticusin mice causes chronic hepatitis and hepatocellular carcinoma (HCC). This study investigated whether helicobacter species could be detected in the liver of patients with HCC.

Methods:Liver samples from 20 patients with primary liver carcinoma diagnosed by histopathology and 16 controls without primary liver carcinoma were studied. Histology with standard and immunohistochemical stains, culture, and polymerase chain reaction (PCR) amplification using helicobacter genus specific 16S rRNA primers were used to detect the presence of bacteria. Amplified products were identified by Southern hybridisation and sequencing. A search for other genes specific forHelicobacter pyloriwas also performed.

Results:Helicobacter species 16S rDNA was found in eight of 20 samples of primary liver carcinoma, whereas none of the controls harboured this rDNA. Six helicobacter specific PCR amplicons were sequenced and were found to have 98.5–99.0% similarity to the 16S rDNA ofH pylori.Of the eight positive samples, seven were positive in PCR using 26 kDa protein primers and six showed morphological and immunohistochemical evidence ofH pylori. The cagA and glmM genes were detected in only two samples. The vacA and rps4 genes were not detected.

Conclusions:Helicobacter can be present in the liver of patients with primary liver carcinoma and is probably linked to the carcinogenic process in the liver.
Surviving acute myocardial infarction: survivin expression in viable cardiomyocytes after infarction: Figure 1
Authors: Santini D , Abbate A , Scarpa S , Vasaturo F , Biondi-Zoccai G G , Bussani R , De Giorgio F , Bassan F , Camilot D , Di Marino M P , Feroce F , Baldi F , Silvestri F , Crea F , Baldi A
Published: November 2004

Background:Apoptosis is a key feature in postinfarction remodelling leading to progressive myocyte loss. Both proapoptotic and antiapoptotic factors contribute to the delicate balance between death and survival. The survivin pathway has emerged as essential in the control of apoptosis, although its role in heart disease is unknown.

Aim:To evaluate survivin expression after acute myocardial infarction (AMI).

Methods:Survivin expression was assessed immunohistochemically in the peri-infarct and remote viable myocardium in 17 consecutive patients who died 1–30 weeks after AMI and in four control hearts.

Results:Survivin was expressed by myocytes in the peri-infarct area in eight patients and in the remote region in 13 patients. The rate of survivin expression after AMI was significantly higher in the remote versus peri-infarct regions and compared with control hearts. Its expression was inversely associated with the presence of dilated cardiopathy and of apoptosis, independently from the gross pathology infarct size.

Conclusions:Survivin myocardial expression after AMI may be associated with the survival of at risk myocardium and may be indicative of more favourable remodelling after AMI. These findings identify a potential new target for the treatment of postinfarction remodelling.
Benign mixed tumour of the skin with extensive ossification and marrow formation: a case report
Authors: Awasthi R , Harmse D , Courtney D , Lyons C B A
Published: November 2004

Benign mixed tumour of the skin (chondroid syringoma) is an uncommon skin adnexal tumour, usually presenting as a slow growing solitary painless nodule. The morphological appearances are similar to those of a pleomorphic adenoma of the salivary gland. Hair matrix and sebaceous differentiation can be seen in some lesions. Focal ossification is a rare finding. This report presents a case of a similar tumour arising in the cheek of a 43 year old white man, showing extensive ossification. Clinical, radiological, and pathological correlation and diagnosis proved to be difficult preoperatively. Only two cases of a benign mixed tumour with pronounced ossification have been reported so far, both in Japanese patients. This is the first reported case seen in a white man. Awareness of these lesions will avoid potential diagnostic pitfalls.
ON THE POWER OF ONE-WAY SYNCHRONIZED ALTERNATING MACHINES WITH SMALL SPACE
Authors: HROMKOVIČ JURAJ , INOUE KATSUSHI , ROVAN BRANISLAV , SLOBODOVÁ ANNA , TAKANAMI ITSUO , WAGNER KLAUS W.
Published: November 2004

This paper continues the investigation of the concept of synchronized alternation. The open problems from Ref. 4 are solved by showing that one-way synchronized alternating (multihead) automata are as powerful as two-way ones. More precisely it is shown that:

(i) one-way synchronized alternating finite automata recognize exactly context-sensitive languages, and

(ii) NSPACE(nk) is exactly the family of languages recognized by one-way (two-way) synchronized alternating k-head finite automata, for k≥1.

Finaly, the synchronization complexity of one-way synchronized Turing machines (1satm's) is investigated and an infinite hierarchy among classes of sets accepted by 1satm's with space and synchronization bounds between log log n and log n is established. Some closure properties of the classes in this hierarchy are also proved.
THE DOT-DEPTH OF A GENERATING CLASS OF APERIODIC MONOIDS IS COMPUTABLE
Authors: BLANCHET-SADRI F.
Published: November 2004

Given a finite alphabet A and a sequence of positive integers [Formula: see text] congruences on A*, denoted by [Formula: see text] and related to a version of the Ehrenfeucht-Fraïssé game, have been defined by Thomas in order to give a new proof that the Brzozowski’s dot-depth hierarchy of star-free languages is infinite. A natural extension of some of the results of Thomas states that the monoid variety corresponding to level k of the Straubing hierarchy (the Straubing hierarchy is closely related to the Brzozowski’s dot-depth hierarchy) can be characterized in terms of the monoids [Formula: see text]. In this paper, it is shown that the dot-depth of the [Formula: see text]’s is computable.
DESIGN OF GENERAL BIDIRECTIONAL ASSOCIATIVE MEMORIES WITH IMPROVED RECALL CAPABILITY
Authors: LEE DONQ-LIANG , CHUANG THOMAS C.
Published: November 2004

The concept of qth order Hamming ball for general bidirectional associative memories (GBAMs) is presented, which results in an enhanced recall capability. A technique based on the minimum overlap algorithm (MOA) is proposed to deal with the separability problem of the qth order Hamming balls. Simulation results show that the recall capability obtained by using the proposed method is indeed larger than that obtained by using the conventional method.
LEARNING TO GENERATE ARTIFICIAL FOVEA TRAJECTORIES FOR TARGET DETECTION
Authors: Schmidhuber Jürgen , Huber Rudolf
Published: November 2004

This paper shows how ‘static’ neural approaches to adaptive target detection can be replaced by a more efficient and more sequential alternative. The latter is inspired by the observation that biological systems employ sequential eye movements for pattern recognition. A system is described, which builds an adaptive model of the time-varying inputs of an artificial fovea controlled by an adaptive neural controller. The controller uses the adaptive model for learning the sequential generation of fovea trajectories causing the fovea to move to a target in a visual scene. The system also learns to track moving targets. No teacher provides the desired activations of ‘eye muscles’ at various times. The only goal information is the shape of the target. Since the task is a ‘reward-only-at-goal’ task, it involves a complex temporal credit assignment problem. Some implications for adaptive attentive systems in general are discussed.
A THREE-LAYER ADAPTIVE NETWORK FOR PATTERN DENSITY ESTIMATION AND CLASSIFICATION
Authors: Wu Jian-xiong , Chan Chorkin
Published: November 2004

Based on the assumption that most probability densities in real life can be approximated by a mixture of Gaussian densities, we propose here a three-layer adaptive network with each neuron in the lower hidden layer representing a Gaussian basis function (covariance matrix equal to [Formula: see text] where I is a unit matrix) to estimate various probability densities and serve as a Bayes classifier. The width of the basis function [Formula: see text] may be the same for all neurons in this layer or it may vary from one neuron to another. This paper investigates the effectiveness of the network for both cases and presents a localized learning algorithm to adjust the network parameters. The network was trained with artificial data derived from known mixtures of memoryless Gaussian sources as well as exponential and Gamma densities. The performance of the network as a pattern density estimator was measured in terms of the relative difference between the target probability density function (p.d.f.) which generates the training and testing data and the network output representing the estimation. Samples from two mixtures corresponding to two classes were used to test the network capability as a classifier by comparing its error rate against that of a Bayes classifier. Both one- and two-dimensional cases were explored. The successfulness of the network depended on how well the target p.d.f.’s were represented by the training samples, the number of hidden neurons employed in the network and how thoroughly the network was trained. It was also found that allowing each basis function to have an independent width had a predominant effect on the network performance.
DIFFERENT RETINAL GANGLION CELLS HAVE DIFFERENT FUNCTIONAL GOALS
Authors: LI ZHAOPING
Published: November 2004

In mammalian retina, the Y (or M) ganglion cells are significantly more transient in response, more selective to stimuli of low spatial and high temporal frequencies and less selective to spectral information than the X (or P) cells. It is shown that these differences in cell properties can be explained by a model that assigns different functional goals to the different ganglion cell types. In this model, the goal of the Y cells is to extract as fast as possible the minimum amount of information necessary for quick responses. In contrast, the goal of the X cells is to extract as much information as possible. Temporal characteristics of the information extraction by the two cell groups are also derived.
LEARNING ATTRACTOR NEURAL NETWORK: THE ELECTRONIC IMPLEMENTATION
Authors: Badoni Davide , Riccardi Roberto , Salina Gaetano
Published: November 2004

In this article we describe the electronic implementation of an attractor neural network with plastic analog synapses. The project for a 27 neurons fully connected network will be shown together with the most important electronic tests we have carried out on a smaller network.
A VISUAL MODEL FOR PATTERN RECOGNITION
Authors: Stringa Luigi
Published: November 2004

A general model for an optical recognition system capable of simultaneous recognition of patterns at different resolution levels is outlined. The model is based on two hierarchic stages of processing networks and presents interesting analogies with the human visual system. Illustrative applications and preliminary experimental results are also briefly discussed.
MEASURING NATURAL NEURAL PROCESSING WITH ARTIFICIAL NEURAL NETWORKS
Authors: Hertz J.A. , Kjær T.W. , Eskandar E.N. , Richmond B.J.
Published: November 2004

We show how to use artificial neural networks as a quantitative tool in studying real neuronal processing in the monkey visual system. Training a network to classify neuronal signals according to the stimulus that elicited them permits us to calculate the information transmitted by these signals. We illustrate this for neurons in the primary visual cortex with measurements of the information transmitted about visual stimuli and for cells in inferior temporal cortex with measurements of information about behavioral context. For the latter neurons we also illustrate how artificial neural networks can be used to model the computation they do.
DYNAMICS OF COHERENCE IN CORTICAL NEURAL ACTIVITY: EXPERIMENTAL OBSERVATIONS AND FUNCTIONAL INTERPRETATIONS
Authors: Aertsen Ad , Vadia Eilon , Abeles Moshe , Ahissar Ehud , Bergman Hagai , Karmon Benny , Lavner Yizhar , Margalit Eyal , Nelken Israel , Rotter Stefan
Published: November 2004

We present results from an ongoing electrophysiological study of cortical function in the awake, behaving monkey. Single and multiple neuron activity is recorded from the frontal cortex, while the monkey is engaged in a sensory-motor association task. Results show that neighboring neurons in the frontal cortex may be functionally related and share common features. However, even when neurons were reduced by the same microelectrode, they were not all activated in unison, nor did they all show the same functional properties. Correlation analysis reveals that interactions between neurons may strongly depend on stimulus context and/or behavioral state. Moreover, the interactions may be highly dynamic, with time constants of modulation as low as tens of milliseconds. These findings point at the need to distinguish between anatomical connectivity and functional coupling. The underlying mechanisms as well as the functional implications of such dynamic coupling in cortical networks are discussed.
HIGH RESOLUTION SOFT X-RAY SPECTROMETER FOR CHEMICAL STATE ANALYSIS BY PIXE
Authors: MAEDA K. , SASA Y. , UDA M.
Published: November 2004

A soft X-ray crystal spectrometer designed for chemical state analysis by PIXE is described. A windowless, microchannel plate (MCP) electron multiplier combined with a photodiode array was used as a position-sensitive detector for X-rays diffracted by a plane crystal. The spectrometer was tested for Al Kα and Fe L X-ray spectra induced by 15 MeV N2+ ion impact. An energy resolution (FWHM) of 1.5 eV for the 1487 eV Al Kα1, 2 line was obtained for metallic Al, and satellite structures of Al Kα arising from multiply ionized states were well resolved. Fe L X-ray spectra were measured for Fe2O3 and metallic Fe. Chemical effects were clearly recognized in the Fe Lα/Lβ intensity ratio and in the intensity distributions of their multiple vacancy satellites.
CHANNELING ANALYSIS OF Ge EPITAXIAL LAYER ON Si SUBSTRATE AND DOPED Ga ATOMS BY USING RBS AND PIXE METHODS
Authors: TANAKA KOKI , YAGI EIICHI , KAWAKAMI KAZUTO , ONO AKIHIRO
Published: November 2004

On the crystalline quality of Ge layers heteroepitaxially grown on Si substrates by the MBE two-step procedure without the intermediate annealing process, the effect of growth temperature and thickness of the first layer was investigated between 135 and 600 °C, and for 20 and 200 nm, respectively, by means of RBS-channeling and cross-sectional TEM methods. The second layer growth temperature was fixed at 600 °C. It was found that, in reducing the total amount of lattice disorder, the two-step procedure has an advantage over the direct deposition, and 200 nm is more favorable than 20 nm as the first layer thickness. The Ge layer of the best quality was obtained when the first layer of 200nm was grown at 400–500 °C, and subsequently the second layer was grown at 600 °C. The PIXE-channeling method was effectively applied to locate Ga atoms doped in the Ge layer grown by the two-step procedure at 300 and 550 °C. Approximately 40% of Ga atoms were located at substitutional sites and the rest at random sites, probably in the form of precipitates.
AUTOMATIZATION OF A PIXE SYSTEM FOR SERIES OF BIO-MEDICAL AND ENVIRONMENTAL ANALYSES
Authors: BAX H. , WÄTJEN U.
Published: November 2004

The PIXE chamber of CBNM, designed for high flexibility in analytical conditions and high throughput of samples, is equipped with stepper motors to serve the various movable components in the chamber. A versatile motor controller was designed which is steering all motors in the chamber, allows for a safety interlock system, and which can readily be expanded or adapted to more and other types of stepper motors if necessary. By interfacing this controller to a computer via the IEEE-488 protocol, it can be remotely controlled in order to automatize complete series of full analysis cycles. An integrated software package has been written, which combines the motor steering—including the necessary safety interlocks—with the control of all MCA functions under a single menu-oriented program. The modular design of the controller and the interfacing by standard IEEE-488 make it portable to other experiment environments.
PREPARATION OF THIN SUPPORT FILM FOR PIXE AND ITS APPLICATION TO TRACE ANALYSIS OF BIOLOGICAL MATERIALS
Authors: IWATA YOSHIHIRO , FUJIWARA TATEKI , SUZUKI NOBUO
Published: November 2004

A thin support film is indispensable to make targets of biological material for trace analysis by PIXE. We developed a simple technique for the preparation of high quality support film. Polyvinylformal (PVF) was dissolved in tetrahydrofuran (THF) and the solution was spread on the surface of sucrose solution. The THF was evaporated and a PVF film formed on the surface. The thickness of the PVF film was 0.1µm with good homogeneity. The PVF film was stable to 3MeV proton bombardment and no impurity elements were observed. The continuous X-ray background was <1/20 that of 280µg/cm2 Mylar. We used the PVF film as a support film for some biological materials. Because of the lower X-ray background from the PVF film, K, Ca, Fe, Ni, Cu, Zn, As and Br in 50–100µg of biological materials could be detected.
SIMULTANEOUS DETERMINATION OF NINE ELEMENTS IN PLASMA OF JAPANESE EELS, Anguilla japonica, INFECTED WITH ATYPICAL Aeromonas salmonicida BY PIXE
Authors: Kakuta I. , Yukawa M. , Kitao K. , Taguchi Y. , Murachi S.
Published: November 2004

Investigations of the levels of nine elements (P, S, Cl, K, Ca, Fe, Cu, Zn, Br) in plasma collected continuously from eels infected with atypical A. salmonicida by PIXE analysis were performed. The PIXE technique proved to be a powerful tool for performing multielement analysis in a small amount of blood collected by an intra-vascular cannulation technique. Decreases in Hb and plasma protein, P, Cl, Ca, Fe and Cu, and increase in plasma K were observed with the infection. On day 3, the reduction in plasma Zn were found in the control and the deseased groups. At the moribund stage, increased ammonia and decreased Br in plasma were observed. The decrease in Fe of the diseased eels was remarkable. No significant change in plasma S was found.
PIXE ANALYSIS OF HILAR GLAND FOR THE EVALUATION OF PERSONAL HISTORY OF EXPOSURE TO ENVIRONMENTAL CONTAMINANTS
Authors: ADACHI SHUICHI , TAKEMOTO KAZUO , SASA YOSHIHIKO , MAEDA KUNIHIKO
Published: November 2004

Seven autopsied cases were studied for the evaluation of individual history of exposure to environmental contaminants based on the elemental profile of hilar gland by PIXE and lung tissue by AAS. The results well characterized their occupational history, especially from Cr, Al, Si and As detection. Moreover, it might be possible that these analyses would provide data to suspect the chemical form of each element in deposited particles of lung parenchyma, since the solubility could reflect the different profile of element between hilar gland and lung parenchyma. In addition to these retrospective analyses using the materials obtained from autopsies, it is possible to assess the individual risk using small quantity of hilar gland or lung tissue obtained by biopsy or surgical resection.
ALUMINUM NEUROTOXICITY IN THE RAT BRAIN
Authors: YUMOTO S. , OHASHI H. , NAGAI H. , KAKIMI S. , OGAWA Y. , IWATA Y. , ISHII K.
Published: November 2004

To investigate the etiology of Alzheimer’s disease, we administered aluminum to healthy rats and examined the aluminum uptake in the brain and isolated brain cell nuclei by particle-induced X-ray emission (PIXE) analysis.

Ten days after the last injection, Al was detected in the rat brain and in isolated brain cell nuclei by PIXE analysis. Al was also demonstrated in the brain after 15 months of oral aluminum administration. Moreover, Al was detected in the brain and isolated brain cell nuclei from the patients with Alzheimer’s disease. Silver impregnation studies revealed that spines attached to the dendritic processes of cortical nerve cells decreased remarkably after aluminum administration. Electron microscopy revealed characteristic inclusion bodies in the hippocampal nerve cells 75 days after the injection. These morphological changes in the rat brain after the aluminum administration were similar to those reportedly observed in the brain of Alzheimer’s disease patients.

Our results indicate that Alzheimer’s disease is caused by irreversible accumulation of aluminum in the brain, as well as in the nuclei of brain cells.
MINERALIZATION OF AORTIC WALL - PIXE STUDIES
Authors: ROKITA E.
Published: November 2004

The application of PIXE and micro-PIXE methods for the description of human aortic wall mineralization including its dynamics is presented. The data was collected both from human autopsy samples and from animal material. The mean concentrations of P, S, Cl, K, Ca, Fe, Cu, Zn, Br, Sr and Pb were determined in tissue samples and in the aortic wall sections. On the basis of PIXE results the following conclusion may be drawn: the concentrations of Ca, Zn, Sr and Pb increase while that of S, Cl and K contents decrease when the mineralization of the vessel wall (determined histochemically) develops. The micro-PIXE method enabled: (1) the determination of the elemental composition of both inorganic and organic materials in the sample, (2) the identification of different Ca—P compounds on the basis of the Ca/P ratio, (3) the investigations of the involvement of other elements in the development of mineralization process (4) the determination of the deposit radii on the basis of Ca concentration and (5) the generalized analysis on the inorganic deposit growth using mathematical description.
ELEMENTAL COMPOSITION OF ATMOSPHERIC AEROSOLS COLLECTED DURING EPISODIC AIR POLLUTION EVENTS IN JAPAN
Authors: Kasahara M. , Choi K-.C. , Takahashi K.
Published: November 2004

More than 3,000 aerosol samples have been collected since 1986 in Kyoto under various meteorological and environmental conditions, including episodic air pollution events such as heavy air pollution, Kosa dust, very clean air, etc. The elemental concentrations of these aerosol samples were determined by PIXE techniques, and elemental concetration data were used to estimate a source contribution of aerosols by applying a receptor model.

The concentrations of Si, K, Ca, Ti and Fe in both coarse and fine fractions increased tremendously at Kosa event. The maximum source contribution of soil dust amounted to 140 μg/m3 for a six hour average during a Kosa event. On the other hand, the concentrations of S, Zn, Pb and Cu in the fine fraction increased remarkably during heavy air pollution and photochemical smog events.
HIGH SPEED BIPOLAR SRAMS — DESIGN CONSIDERATIONS AND ADVANCES
Authors: CHUANG C.T.
Published: November 2004

This paper reviews the design considerations and recent advances in high speed bipolar static random access memories (SRAMs). The design constraints and limitations of some most commonly used bipolar SRAM cells, including the resistor-loaded Schottky-clamped ECL cell, the pnp-loaded ECL cell, and the MTL/L2L cell, are examined. Process modification, device optimization, and circuit innovation to address these constraints and limitations are discussed. The density and performance potential of these cells are projected.
A GaAs8×8 CROSS-POINT SWITCH FOR HIGH SPEED DIGITAL COMMUNICATIONS
Authors: MITTAL MANISH , SALAMA C. ANDRE T.
Published: November 2004

Design of a 1.9 Gbits/s, 8×8 cross-point switch using nonself-aligned 1 µm D-MESFET GaAs technology is presented. An 8×1 switch bit-slice was fabricated and tested. Experimental results are provided to verify the functionality and performance of the bit-slice. The bit-slice occupies an area of 0.512×0.711 mm 2 (including the 50 Ω output drivers and excluding the input/output pads) dissipating 192 mW of power (including the output drivers). The performance of the 8×8 cross-point is estimated on the basis of the performance of the 8×1 bit-slice.
BEAR-FP: A ROBUST FRAMEWORK FOR FLOORPLANNING
Authors: PEDRAM MASSOUD , KUH ERNEST S.
Published: November 2004

This paper presents a hierarchical floorplanning approach for macrocell layouts which is based on the bottom-up clustering, shape function computation, and top-down floorplan optimization with integrated global routing and pin assignment. This approach provides means for specifying and techniques for satisfying a wide range of constraints (physical, topological, timing) and is, therefore, able to generate floorplans for a number of different layout styles. A systematic and efficient optimization procedure during the selection of suitable floorplan patterns that integrates floorplanning, global routing and pin assignment, a new pin assignment technique based on linear assignment and driven by the global routing solution and floorplan topology, and an effective timing-driven floorplanning scheme are among the other novel features of the floorplanner. These techniques have been incorporated in BEAR-FP, a macrocell layout system developed at the University of California, Berkeley. Results on various placement and floorplanning benchmarks are quite good.
UNIFIED GaAs MESFET MODEL FOR CIRCUIT SIMULATIONS
Authors: SHUR M.S. , FJELDLY T.A. , YTTERDAL T. , LEE K.
Published: November 2004

We describe a new, unified model for MEtal Semiconductor Field Effect Transistors (MESFETs) which covers all ranges of operation, including the subthreshold regime. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics are described by continuous, analytical expressions with relatively few, physically based parameters. The model includes effects such as velocity saturation, parasitic series resistances, the dependence of the threshold voltage on drain bias, finite output conductance in saturation, and temperature dependence of the device parameters. We also describe a parameter extraction routine which allows the model parameters to be derived in a straightforward fashion from experimental data. The model has been incorporated into our new circuit simulator AIM-Spice. The new device characterization is applied with good results to a typical ion-implanted GaAs MESFET and a delta-doped MESFET.
ELECTRICAL SUBCARRIER-MULTIPLE-ACCESS FOR LIGHTWAVE NETWORKS
Authors: SHANKARANARAYANAN N.K. , LAU KAM Y.
Published: November 2004

Multiplexing of information on microwave carriers, whose frequencies are within the direct modulation and detection bandwidths of semiconductor lasers and photoreceivers, can be used to provide multiple concurrent channels for lightwave networks in multiaccess applications. This is in effect an electrical multiplexing scheme applied to optical systems which is referred to as “Subcarrier Frequency-Division Multiple Access” (SFDMA). This paper provides an introduction to this subject, which includes discussions on factors that determine the performance of such a network as well as network architecture issues.
KOBAYASHI CONFORMAL METRIC ON MANIFOLDS, CHERN-SIMONS AND η-INVARIANTS
Authors: APANASOV BORIS N.
Published: November 2004

The main aim of this paper is to present a canonical Riemannian smooth metric on a given uniformized conformal manifold (conformally flat manifold) which is compatible with the conformal structure. This metric is related to the Kobayashi construction for complex-analytic manifolds and gives a new conformal invariant.

As an application, the paper studies the Chern-Simons functional and the η-invariant associated with the conformal class of conformally-Euclidean metrics on a closed hyperbolic 3-manifold.
FREE-PRODUCT GROUPS, CUNTZ-KRIEGER ALGEBRAS, AND COVARIANT MAPS
Authors: SPIELBERG JOHN
Published: November 2004

A construction is given relating a finitely generated free-product of cyclic groups with a certain Cuntz-Krieger algebra, generalizing the relation between the Choi algebra and 02. It is shown that a certain boundary action of such a group yields a Cuntz-Krieger algebra by the crossed-product construction. Certain compact convex spaces of completely positive mappings associated to a crossed-product algebra are introduced. These are used to generalize a problem of J. Anderson regarding the representation theory of the Choi algebra. An explicit computation of these spaces for the crossed products under study yields a negative answer to this problem.
GENERALIZED CONNECTIONS AND CHARACTERISTIC CLASSES
Authors: KIM HONG-JONG
Published: November 2004

We study derivations on a smooth manifold, its twisted de Rham cohomology, generalized connections on vector bundles and their characteristic classes.
FINITE-DIMENSIONAL REPRESENTATIONS OF FREE PRODUCT C*-ALGEBRAS
Authors: EXEL RUY , LORING TERRY A.
Published: November 2004

Our main theorem is a characterization of C*-algebras that have a separating family of finite-dimensional representations. This characterization makes possible a solution to a problem posed by Goodearl and Menaul. Specifically, we prove that the free product of such C*-algebras again has this property.
ON DISCRETE SEMIGROUPS OF *-ENDOMORPHISMS OF TYPE I FACTORS
Authors: DINH HUNG T.
Published: November 2004

The purpose of this paper is to study semigroups of *-endomorphisms of type I factors, with parameters in a countable dense subgroup of the real line. Most of our results are motivated by the theory of semigroups of isometries. It is shown that every semigroup of *-endomorphisms can be extended to a group of *-automorphisms in a minimal way. In certain situations, it is shown that a semigroup of *-endomorphisms can be decomposed into three simpler semigroups. Shifts are defined and classified up to outer conjugacy.
The Impact of Modern Graphics Tools on Science, and their Limitations
Authors: ETIENNE F.
Published: November 2004

Within the last few years the range of scientific applications for which computer graphics is used has become extremely large. However, not all scientists require the same level of computing power.

Until recently the software interface to graphics display systems has been provided by the manufacturers of the hardware. This generated interest in the possibility of using graphics standards. Another important issue is related to the deluge of data generated by super-computers and high-volume data sources which make it impossible for users to have an overall knowledge of either the data structures or the application programs. Partial solutions can be found in emerging products providing an interactive computational environment for scientific visualization.

Some of the characteristics required for graphics hardware are presented. From a hardware perspective, graphics computing involves the use of a graphical computer system with sufficient power and functionality that the user can manipulate and interact with displayed objects. To achieve such a level of performance computers are usually designed as networked workstations with access to local graphics capabilities. Finally, it is made clear that the main computer graphics applications are scientific activities. From high energy physics experiments with wireframe event displays up to medical imaging with interactive volume rendering, scientific visualization is not simply displaying data from data intensive sources. Fields of computer graphics like image processing, computer aided design, signal processing and user interfaces provide tools helping researchers to understand and steer scientific computation.
Fast Algorithms for Slow Processes in Lattice-Gas Cellular Automata
Authors: FRENKEL D.
Published: November 2004

The accurate numerical study of long-time tails in time-correlation functions requires large amounts of computer time. In some cases, the necessary calculations are too time-consuming to be carried out even on present-day (super)computers. However, if we consider ‘lattice-gas’ versions of the same problems, then it turns out that for certain problems, a speed-up of 6–10 orders of magnitude can be achieved using a very simple algorithm. As a result, we can now test theoretical (mode-coupling) predictions for long-time tails with unprecedented accuracy.
Three-Dimensional Ideal Magnetohydrodynamic Stability on Parallel Machines
Authors: SCHWENN ULRICH , COOPER W. ANTHONY , FU GUO Y. , GRUBER RALF , MERAZZI SILVIO , ANDERSON DAVID V.
Published: November 2004

On the path towards a thermonuclear fusion reactor there are several technological and physical uncertainties to be understood and solved. One of the most fundamental problems is the appearance of many sorts of instabilities which can either enhance the energy outflow or even destroy the magnetic confinement of the fusion plasma. The knowledge of such instabilities is a prerequisite to a good understanding of the behaviour of actual experiments, and to the design of new devices. Most of the effort is devoted to the study of axisymmetric toroidal configurations such as tokamaks or spheromaks and to helically twisted toroidal devices such as stellarators.
Electric Field Lines
Authors: ARRIBAS E. , GALLARDO C. , MOLINA M. , SANJOSÉ V.
Published: November 2004

We present the computer program called LINES which is able to calculate and visualize the electric field lines due to seven different discrete configurations of electric point charges. Also we show two examples of the graphic screens generated by LINES.
Finite Difference, Finite Element and Boundary Element Formulae as a Language of Applied Physics
Authors: KAFKA JIŘÍ , NHAC NGUYEN VAN
Published: November 2004

When deducing the finite difference formulae, one has to discretize partial differential equations. On the other hand, those equations have been previously derived having started from laws of physics in their integral form. So, a question arises, why not avoid the approach to the limit (necessary to deduce the partial differential equation) and why not deduce the finite difference formulae directly on the base of laws of physics in their integral form.
Multiphoton Ionization
Authors: KARULE ERNA
Published: November 2004

Multiphoton ionization happens in an intense light beam when atoms absorb more than one photon. In strong fields an atom may absorb not only the minimum energetically necessary number of photons for ionization, but also excess photons. The last process is the so called “above threshold ionization” (ATI) which as well as “normal” multiphoton ionization (MPI) takes place in the strong laser fields. Both processes are between those responsible for the energy transfer from the laser to the plasma.

The paper deals with the quantum mechanical calculation of MPI and ATI of atomic hydrogen. At the moderate intensities of light these processes may be treated by methods of perturbation theory.
PARALLELIZATION OF THE WORLDLINE QUANTUM MONTE CARLO METHOD
Authors: GUBERNATIS J.E. , SOMSKY W.R.
Published: November 2004

The worldline quantum Monte Carlo method is a computational technique for studying the properties of many-electron and quantum-spin systems. In this paper, we describe our efforts in developing an efficient implementation of this method for the massively-parallel Connection Machine CM-2. We discuss why one must look beyond the obvious parallelism in the method in order to reduce interprocessor communication and increase processor utilization, and how these goals may be achieved using a plaquette-based data representation. We also present performance statistics for our implementation and sample calculations for the spinless fermion model.