bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Experimental Study of Step Dynamics under the Influence of Electromigration: Si(111)
Authors: Métois J.-J. , Audiffren M. 
Published: October 2003

The velocity of monoatomic step motion in the neighborhood of a bunch has been measured in situ using a UHV electron microscope. The width of step bunches at different temperatures and the intrinsic time that lead to step bunching have also been determined. Direct and alternating current were used to heat the Silicon(111) between 1000°C and 1300°C. The results show that the diffusion regime prevails. The asymmetry of the surface diffusion of adatoms is proved experimentally. It is consistent with the adatom electromigration effects. The surface diffusion field under the influence of an electric current can induce an attractive force between the steps. This force balances the step-step repulsive interactions (entropic and energetic) inside the bunch and stabilizes its width. The effective charge on the adatom has been estimated from the critical frequency of AC when the step bunching does not operate. It is around 0.001 electron.
Determination of the Donor–Acceptor Pair Separation in GaP Semiconductor Doped with Sulfur and Zinc Using its Photoluminescence Spectrum
Authors: Baskoutas S. , Athanasiou N.S. 
Published: October 2003

Considering the gallium phosphide (GaP) semiconductors doped with sulfur (S) and zinc (Zn) acceptors, we have studied the behavior of Huang-Rhys factor S theor as a function of the donor–acceptor (D–A) pair separation R. It turned out that the form of the bands — broad or narrow — that are attributed to (D–A) recombination, depends on the values of the pair separation — large or small, respectively. More specifically for R=0.5 nm we obtain S theor =0.117 and for R=3.5 nm, S theor =3.616. The above values of the factor S impose sub-Poissonian (with ℏω=49.97 meV) and super-Poissonian (with ℏω=78 meV) distribution shapes on the bands.
Low Power Design for Wireless RF Transceiver–An Industrial View
Authors: Wang Nan-Lei , Adam Douglas 
Published: October 2003

In recent years, wireless communication in the radio frequency has a rapid growth, most noticeably the cellular phone. Analog FM systems, such as AMPS and TACS, have won a great success. In the 90s, digital systems appear, such as GSM in Europe, IS54/136 and IS95 in US, and PDC in Japan. Most recently, PCS draws the attention; there are many standards proposed around the world and they all use digital modulation schemes. With the ISM bands at 900 MHz and 2.4 MHz, many other innovative application will become possible. Unlike the computer such RF wireless gadgets contain one peculiar subsystem: the RF transceiver. The RF transceiver translates the baseband voice and data to and from a radio frequency signal which is emitted and received by antennae. Each system specifies the operation frequency, the transmit power, the receiver sensitivity, and the signal quality. The RF transceiver must satisfy all these requirements. As technology progresses, portable product becomes the dominant one which relies on the rechargeable battery. To maintain a decent talk time standby time, the completed product must be designed with low power consumption in mind. In the portable cellular phone the RF transceiver faces the greatest challenge in the low power design since it is the most power hungry portion: the transmitter consumes 90% power during transmission in the FM cellular phone nowadays. To achieve low power consumption of the RF transceiver, the designer has to work to: (1) transceiver architecture to reduce parts count and therefore power comsumption. (2) selection/design the lowest power comsumption IC/module for a given function block. (3) maintain competitive pricing and small size. In this article, FM system will be used as the baseline example to illustrate the importance of the RF transceiver in low power application. The RF transceiver architecture is described first, followed by the introduction to each function block. State-of-the-art products for each function block will be referred to. Theorectical limit of power consumption for each block will be discussed. Impact from digital modulation on RF circuit design will be reviewed as well.
Power-Area Trade-Offs in Divided Word Line Memory Arrays
Authors: Chang Meng-Fan , Irwin Mary Jane , Owens Robert Michael 
Published: October 2003

Since on-chip caches account for a significant portion of the power budget of modern microprocessors, low power caches are needed in microprocessors destined for portable electronic applications. A significant portion of the power consumption of caches comes from accessing the cache memory array and most of the power consumption of the memory array comes from driving the bit line pairs (i.e., the column current). Various memory array architectures have been proposed to improve the word line delay and the column current. For example, in a divided word line memory array memory cells in each row are organized into blocks. Only the memory cells which are in the activated block have their bit line pairs driven, thus both improving the speed (by decreasing the word line delay) and lowering the power consumption (by decreasing the column current). In this paper we analyze the power-area tradeoffs of divided word line memories with different size blocks. We compare the area and power consumption of 16 Kbit and 64 Kbit memory arrays with 2, 4, 8, and 16 memory cells per block. Our experiments show that a divided word line memory array can lower the power consumption by 50% to 90% over a nondivided word line memory array. However, they consume more area; the area of a divided word line memory array can be 15% to 27% larger than the area of a comparable nondivided word line array. Our experiments also showed that divided word line memory arrays with two or four memory cells in a block have better power-area product than those with more than four cells per block.
A Nonlinear Dynamics Perspective of Wolfram's New Kind of Science Part II: Universal Neuron
Authors: Chua Leon O. , Sbitnev Valery I. , Yoon Sook 
Published: October 2003

Wolfram's celebrated three-input Cellular Automata is further developed and extended from the perspective of neural networks. A single explicit formula involving two nested absolute-value functions and eight adjustable parameters called synaptic weights, is presented. Such a neuron is proved to be universal by specifying the synaptic weights of all 256 local rules. Applying the nonlinear dynamics concepts developed from Part I of this multipart series of papers, we present the rational for partitioning the entire set of 256 local rules into 16 distinct gene families, each composed of 16 gene siblings. Such a partitioning allows us to explain, if not predict, the pattern features generated from each local rule. Finally, these 16 gene families of Cellular Automata rules are encoded onto a new compact and insightful representation called the "double-helix torus."
Finding a Covering Triangulation Whose Maximum Angle is Provably Small
Authors: Mitchell Scott A. 
Published: October 2003

We consider the following problem: given a planar straight-line graph, find a covering triangulation whose maximum angle is as small as possible. A covering triangulation is a triangulation whose vertex set contains the input vertex set and whose edge set contains the input edge set. The covering triangulation problem differs from the usual Steiner triangulation problem in that we may not add a vertex on any input edge. Covering triangulations provide a convenient method for triangulating multiple regions sharing a common boundary, as each region can be triangulated independently. We give an explicit lower bound γopt on the maximum angle in any covering triangulation of a particular input graph in terms of its local geometry. Our algorithm produces a covering triangulation whose maximum angle γ is provably close to γopt. Specifically, we show that [Formula: see text], i.e., our γ is not much closer to π than is γopt. To our knowledge, this result represents the first nontrivial bound on a covering triangulation's maximum angle. Our algorithm adds O(n) Steiner points and runs in time O(n log n), where n is the number of vertices of the input. We have implemented an O(n2) time version of our algorithm.
Matching Shapes with a Reference Point
Authors: Aichholzer Oswin , Alt Helmut , Rote Günter 
Published: October 2003

For two given point sets, we present a very simple (almost trivial) algorithm to translate one set so that the Hausdorff distance between the two sets is not larger than a constant factor times the minimum Hausdorff distance which can be achieved in this way. The algorithm just matches the so-called Steiner points of the two sets. The focus of our paper is the general study of reference points (like the Steiner point) and their properties with respect to shape matching. For more general transformations than just translations, our method eliminates several degrees of freedom from the problem and thus yields good matchings with improved time bounds.
Bremsstrahlung and Pair Creation by a Photon in the Spacetime of a Cosmic String
Authors: Bayer Rolf M. , Lotze Kaerl-Heinz 
Published: October 2003

We consider two tree-graph processes in the spacetime of an infinite, straight and static cosmic string, namely Bremsstrahlung and electron–positron pair production. Results based on a simplified model with scalar fields which were obtained by other authors are extended to the more realistic QED case. In empty Minkowski spacetime, energy and momentum conservation preclude these processes. In spite of the local flatness of the metric, it is a topological defect that gives rise to non-conservation of momentum in the plane perpendicular to the string. Analytic expressions for the total transition probabilities and, in the case of Bremsstrahlung, the total radiation energy are found and compared with the results for the scalar field model. In a sense, the cylindrical mode solutions of the Dirac equation allow a spatial localisation of the decay processes relative to the string axis.
Normalizing Possibility Distributions Using t-Norms
Authors: Recasens J. , Lawry J. 
Published: October 2003

A new approach to normalizing fuzzy sets is introduced where it is assumed that the normalization method is compatible with a given t-norm. In this context it is proved that the most usual ways to normalize fuzzy subsets correspond to the most common t-norms. For a given fuzzy subset μ, the corresponding normalized fuzzy subset [Formula: see text] can be viewed as the distribution of μ conditioned on the (degree of) existence of its elements with maximal membership. From this view point we investigate the less specific normal fuzzy subset of X among the most similar fuzzy subsets to μ and the normal fuzzy subset generating the same fuzzy T-preorder as μ.
Clinical Relevance of the SYT-SSX Fusion Gene in Synovial Sarcoma
Authors: Hashimoto N. , Araki N. , Fukuda H. , Kudawara I. , Yoshikawa H. , Uchida A. , Ochi T. 
Published: October 2003

Recent molecular analyses have reported that the specific translocation t(X;18) (p11.2;q11.2) in synovial sarcoma induces the fusion of the SYT gene on chromosome 18 to either of two duplicated genes on chromosome X, SSX1 or SSX2. As a result, two types of fusion genes SYT-SSX1 and SYT-SSX2, whose products play major roles in tumorigenesis, are formed. However, the precise function of the fusion genes is still unclear. To determine clinical relevance of the SYT-SSX fusion genes, we analyzed the fusion transcripts in 13 synovial sarcomas by reverse transcription-polymerase chain reaction (RT-PCR) and also determined the subtype by restriction enzyme assay. These molecular results were compared with certain clinical features of the tumors. The SYT-SSX fusion transcript was detected in the majority of the cases (11 / 13) with synovial sarcoma, suggesting that it is a useful diagnostic marker. The subtype analysis showed that only the recurrent tumors expressed SYT-SSX2. This may indicate that there are some biological differences between the two subtypes, such as transforming activity. On this basis, SYT-SSX2 may correlate with the progressive character of this tumor and could be a predictor of prognosis.
Inflammatory Cytokines, Pleuropneumonia Infection and the Effect of Dexamethasone
Authors: Myers Michael J. , Farrell Dorothy E. , Snider 3rd T.G. Ron , Post Lynn O. 
Published: October 2003

<i>Objectives:</i><i>Actinobacillus pleuropneumoniae</i> causes an often fatal infection of swine due to pleuropneumonia. To determine if inflammatory cytokines are associated with <i>A. pleuropneumoniae</i>-induced pneumonia, infected and noninfected animals were concomitantly administered saline or dexamethasone. <i>Methods:</i> Twenty-four swine were treated with saline, <i>A. pleuropneumoniae</i>, dexamethasone, or <i>A. pleuropneumoniae</i> and dexamethasone (n = 6). The plasma levels of TNF-α, IL-1β, IL-6, IL-8, and IL-10 were examined through time of necropsy (72 h). Gross pathology and histopathology was performed on all animals. <i>Results:</i> Dexamethasone had no effect on <i>A. pleuropneumoniae</i>-induced increases in lung/body weight ratios. Gross pathology of the infected pigs included fibrinous pleuropneumonia with necrosis and hemorrhage in a focal to a multifocal pattern. Histopathology of infected pig lungs revealed necrotizing extensive, fibrinopurulent pneumonia with edema and fibrinopurulent pleuritis. Plasma IL-6 levels were elevated in <i>A. pleuropneumoniae</i>-infected animals beginning 6 h after infection. Dexamethasone treatment did not alter <i>A. pleuropneumoniae-</i>induced plasma IL-6 levels. <i>A. pleuropneumoniae</i> infection did not elicit plasma levels of TNF-α, IL-1β, IL-8, or IL-10. <i>Conclusion:</i> These results suggest that the pneumonia caused by <i>A. pleuropneumoniae</i> infection is not due to the release of systemic inflammatory cytokines.
Soluble E-selectin in cardiovascular disease and its risk factors
Authors: Roldán Vanessa , Marín Francisco , Lip Gregory , Blann Andrew 
Published: October 2003

SummaryThe initial steps in the pathogenesis of atherosclerosis involve changes to the vascular endothelium, which produces numerous substances involved in the regulation and maintenance of vascular integrity and the homeostasis of the coagulation/fibrinolysis system. A further change in endothelial physiology is an increase in the surface expression of cell adhesion molecules, such as E-selectin, which regulate adhesive interactions between certain blood cells and endothelium. As E-selectin is only expressed on activated endothelium, it therefore provides an opportunity to study pathophysiological aspects of this cell in cardiovascular and other disease. However, a soluble form of E selectin (i.e. sE-selectin) can be found in the plasma. This review will focus on sE-selectin, and its potential role in the pathogenesis of cardiovascular disease as raised levels have been found in hypertension, diabetes and hyperlipidemia, although its association in established atherosclerosis disease and its value as a prognostic factor is more controversial.Search strategy: We performed a keyword search (listed above) using electronic databases (PUB-MED, MEDLINE, EMBASE, DARE), and additionally, abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors of these studies were contacted to obtain further data.
Allele 4G of gene PAI-1 associated with prothrombin mutation G20210A increases the risk for venous thrombosis
Authors: Barcellona Doris , Fenu Lara , Cauli Cristiana , Pisu Giulia , Marongiu Francesco 
Published: October 2003

SummarySeveral studies have tried to clarify the role of polymorphism 4G/5G of the PAI-1 gene in venous thromboembolism without reaching any final conclusion. It has been demonstrated that this polymorphism may induce an increased risk for venous thromboembolism (VTE) in patients with thrombophilic defects. We studied the association of prothrombin mutation G20210A with 4G/5G polymorphism in 402 VTE patients and 466 healthy controls. Patients affected by prothrombin mutation G20210A, with or without the concomitant presence of allele 4G, had a 3.7 thrombotic risk (C.I. 95% 2.3–6.0; p<0.0001). Moreover, genotype 4G/4G is a mild risk factor for VTE, irrespectively of whether the prothrombin mutation was present.Logistic regression analysis showed that patients carrying the G20210A prothrombin mutation with allele 4G gave an odds ratio for VTE of 6.1 (C.I. 95% 3.2 – 11.4; p<0.001). The risk increased up to 13.0 (C.I. 95% 3.0 – 60.4; p<0.001) when we considered the association of the prothrombin mutation with genotype 4G/4G. The G20210A mutation without allele 4G (5G/5G) was not a risk factor for VTE. In conclusion, we believe that patients affected by VTE with concomitant presence of the G20210A prothrombin mutation could be tested for genotype 4G/4G to better define their thrombotic risk.
Markers of endothelial activation and atherothrombosis in women with history of preeclampsia or gestational hypertension
Authors: Ford Isobel , Morrison Rona , Prescott Gordon , Watson Stuart , Hannaford Philip , Smith Cairns , Campbell Doris , Greaves Michael , Vickers Mark 
Published: October 2003

SummaryWomen who have had preeclampsia (PE) or gestational hypertension (GH) exhibit relatively high rates of circulatory diseases. PE is a disease associated with inflammation and vascular endothelial dysfunction. We therefore hypothesised that women with a history of PE or GH might have abnormal levels of markers of endothelial activation or inflammation, reflecting either an innate predisposition to preeclampsia or changes induced by the eclamptic process. Levels of von Willebrand factor, fibrinogen and C-reactive protein were compared in 392 women with a history of PE between 1951 and 1970, 297 women with a history of GH and 163 matched controls. Although no significant differences between those with either PE or GH and controls were noted, subjects with a history of PE had significantly higher CRP values than those with GH. No significant differences were found when the three groups were compared for von Willebrand factor or fibrinogen. Overall, the data do not support our hypothesis.In addition, our data document increasing von Willebrand factor levels increase with age, which may help explain the age dependent increase in venous or arterial thrombosis. Moderate alcohol consumption was also associated with lower levels of inflammatory markers.
Reduction of venous thromboembolism following prolonged prophylaxis with the low molecular weight heparin Certoparin after endoprothetic joint replacement or osteosynthesis of the lower limb in elderly patients
Authors: Bodamer Iris , Galster Heide , Seidlmayer Christoph , Grambach Konrad , Koudela Karel , Eisele Ralf , Becker Clemens , Paal Valerie , Spannagel Uwe , Brom Joachim , Weidinger Gottfried , Kolb Gerald 
Published: October 2003

SummaryThe peri- and postsurgical thromboembolic prophylaxis with low molecular weight heparins is a well established therapy regimen, but the optimum duration of prophylaxis after surgery still remains uncertain. A few studies have pointed to the fact that the thromboembolic risk of high-risk patients persists longer than the in-hospital period correlating with respective hypercoagulatory conditions. The aim of the present study was to test if a prolongation of thromboprophylaxis with the low molecular weight heparin Certoparin further reduces the rate of thromboembolism in high-risk patients after orthopedic surgery. The “Long-term Thromboprophylaxis”-Study was a multicenter, randomized, double-blind, placebo-controlled trial. 360 patients who underwent endoprothetic joint replacement or osteosyn-thesis of the lower limb were initially enrolled, all of them received prophylactically 3000 U anti-Xa of Certoparin once daily for 14 days followed by randomization to prolonged Certoparin application or to placebo up to day 42. Patients were screened for deep vein thrombosis by sonography every week. Coagulation markers (fibrin monomers and D-dimers) were determined during the course of the study.Venous thromboembolism during the prolongation period was observed in 18 patients receiving placebo versus 8 patients of the prolonged Certoparin group (12.1% versus 5.0%, intention-to-treat sample). The analysis revealed a statistically significant difference in favor of Certoparin (p=0.020), which was confirmed by per-protocol analysis (14.2% versus 5.5%, p=0.012). The differences remained significant, if analyses considered only clinically symptomatic thromboembolic events (p=0.040). Patients who developed a thrombosis showed a strong increase of coagulation markers as compared to patients without subsequent thrombosis. The respective differentiation started around 18 days before diagnosis of thrombosis. Only one minor bleeding complication was observed during prolonged Certoparin prophylaxis.The present study shows that patients after joint replacement or osteosynthesis of the lower extremities have a persisting risk to develop thromboembolic complications beyond the routine duration of thromboprophylaxis. Extended prophylaxis with Certoparin resulted in a significantly lower rate of thromboembolism and should be strongly recommended.
A multi-centre collaborative study on the potency estimation of ReFacto
Authors: Sands Dawn , Sandberg Eva , Seitz Rainer , Barrowcliffe Trevor , Hubbard Anthony 
Published: October 2003

SummarySeven laboratories estimated factor VIII coagulant activity in recombinant B-domain-deleted (ReFacto) and plasma-derived FVIII concentrates (Octonativ-M) using chromogenic methods relative to the WHO 6th International Standard FVIII Concentrate (WHO 6th IS), European Pharmacopoeia BRP#2 (EP#2) and the ReFacto Laboratory Standard (RLS). Significantly higher estimates were obtained for all batches of product when calculated relative to the RLS in comparison with estimates vs WHO 6th IS and EP#2. Mean estimates for two batches of ReFacto product vs the RLS were within 10% of the labelled potency whereas estimates vs WHO 6th IS and EP#2 ranged from 21 to 31% lower than the label. Conversely, mean estimates for Octonativ-M relative to WHO 6th IS and EP#2 were within 10% of the label whereas the mean estimate vs RLS was 117% of label. Mean estimates for the ReFacto product, vs the WHO 6th IS and EP#2, varied considerably between the different chromogenic kits whereas estimates vs the RLS showed good agreement between kits. Mean estimates for the RLS vs the WHO 6th IS (8.10 IU/vial) and the EP#2 (7.66 IU/vial) were lower than the assigned value of 9.4 IU/vial. The results are consistent with ReFacto and full-length FVIII responding differently to variations in assay methodology and also indicate that the assigned value on the RLS may be too high. Since this study the unitage on the RLS has been adjusted to effectively increase the amount of ReFacto in the product by 20%.