bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFICIENT AUTOMATA CONSTRUCTIONS AND APPROXIMATE AUTOMATA
Authors: WATSON BRUCE W. , KOURIE DERRICK G. , STRAUSS TINUS , KETCHA ERNEST , CLEOPHAS LOEK
Published: February 2008

In this paper, we present data structures and algorithms for efficiently constructing approximate automata. An approximate automaton for a regular language L is one which accepts at leastL. Such automata can be used in a variety of practical applications, including network security pattern matching, in which false-matches are only a performance nuisance. The construction algorithm is particularly efficient, and is tunable to yield more or less exact automata.
AN ASYMPTOTIC LOWER BOUND FOR THE MAXIMAL NUMBER OF RUNS IN A STRING
Authors: FRANEK FRANTISEK , YANG QIAN
Published: February 2008

An asymptotic lower bound for the maxrun function ρ(n) = max {number of runs in string x | all strings x of length n} is presented. More precisely, it is shown that for any ε > 0, (α−ε)n is an asymptotic lower bound, where [Formula: see text]. A recent construction of an increasing sequence of binary strings “rich in runs” is modified and extended to prove the result.
A NORMAL FORM FOR FIRST-ORDER LOGIC OVER DOUBLY-LINKED DATA STRUCTURES
Authors: LINDELL STEVEN
Published: February 2008

We use singulary vocabularies to analyze first-order definability over doubly-linked data structures. Singulary vocabularies contain only monadic predicate and monadic function symbols. A class of mathematical structures in any vocabulary can be elementarily interpreted in a singulary vocabulary, while preserving notions of total size and degree. Doubly-linked data structures are a special case of bounded-degree finite structures in which there are reciprocal connections between elements, corresponding closely with physically feasible models of information storage. They can be associated with logical models involving unary relations and bijective functions in what we call an invertible singulary vocabulary. Over classes of these models, there is a normal form for first-order logic which eliminates all quantification of dependent variables. The paper provides a syntactically based proof using counting quantifiers. It also makes precise the notion of implicit calculability for arbitrary arity first-order formulas. Linear-time evaluation of first-order logic over doubly-linked data structures becomes a direct corollary. Included is a discussion of why these special data structures are appropriate for physically realizable models of information.
NONLINEAR TIME SERIES PREDICTION BASED ON A POWER-LAW NOISE MODEL
Authors: EMMERT-STREIB FRANK , DEHMER MATTHIAS
Published: February 2008

In this paper we investigate the influence of a power-law noise model, also called Pareto noise, on the performance of a feed-forward neural network used to predict nonlinear time series. We introduce an optimization procedure that optimizes the parameters of the neural networks by maximizing the likelihood function based on the power-law noise model. We show that our optimization procedure minimizes the mean squared error leading to an optimal prediction. Further, we present numerical results applying our method to time series from the logistic map and the annual number of sunspots and demonstrate that a power-law noise model gives better results than a Gaussian noise model.
CONTINUOUS OPINION DYNAMICS UNDER BOUNDED CONFIDENCE: A SURVEY
Authors: LORENZ JAN
Published: February 2008

Models of continuous opinion dynamics under bounded confidence have been presented independently by Krause and Hegselmann and by Deffuant et al. in 2000. They have raised a fair amount of attention in the communities of social simulation, sociophysics and complexity science. The researchers working on it come from disciplines such as physics, mathematics, computer science, social psychology and philosophy.

In these models agents hold continuous opinions which they can gradually adjust if they hear the opinions of others. The idea of bounded confidence is that agents only interact if they are close in opinion to each other. Usually, the models are analyzed with agent-based simulations in a Monte Carlo style, but they can also be reformulated on the agent's density in the opinion space in a master equation style. The contribution of this survey is fourfold. First, it will present the agent-based and density-based modeling frameworks including the cases of multidimensional opinions and heterogeneous bounds of confidence. Second, it will give the bifurcation diagrams of cluster configuration in the homogeneous model with uniformly distributed initial opinions. Third, it will review the several extensions and the evolving phenomena which have been studied so far, and fourth it will state some open questions.
MULTIPARTY QUANTUM SECRET SHARING SCHEME OF CLASSICAL MESSAGES BY SWAPPING QUDIT-STATE ENTANGLEMENT
Authors: ZHANG ZHAN-JUN , LIU YI-MIN , FANG MING , WANG DONG
Published: February 2008

A multiparty quantum secret sharing scheme based on Bell-state entanglement swapping [Z. J. Zhang and Z. X. Man (2005)] is generalized to the qutrit case, that is, with qutrit-pair entangled states we propose a multiparty quantum secret sharing (QSS) scheme of classical messages by swapping qutrit-state entanglement. The security of our scheme is analyzed and confirmed with respect to some attacks. Compared to the scheme being generalized, this scheme possesses the distinct advantages of higher code capacity and higher security. Moreover, the generalization of the scheme to the qudit case is also outined.
SIMULATION OF GENERALIZED NEWTONIAN FLUIDS WITH THE LATTICE BOLTZMANN METHOD
Authors: MALASPINAS ORESTIS , COURBEBAISSE GUY , DEVILLE MICHEL
Published: February 2008

This paper proposes a study of the computational efficiency of a lattice Boltzmann model (LBM) solver to simulate the behavior of a generalized Newtonian fluid. We present recent progress concerning a 4-1 planar contraction considering a power-law and a Carreau-law model. First we compare the power-law model for a Poiseuille flow with the analytical solution, and show that our model is second-order accurate in space. Then we compare the results obtained with LBM for both laws to those obtained using a commercial finite element solver for the 4-1 plane sharp corner contraction.
MODEL INSPIRED BY POPULATION GENETICS TO STUDY FRAGMENTATION OF BRITTLE PLATES
Authors: GOMES M. A. F. , de OLIVEIRA VIVIANE M.
Published: February 2008

We use a model whose rules were inspired by population genetics and language competition, the random capability growth model, to describe the statistical details observed in experiments of fragmentation of brittle plate-like objects, and in particular the existence of (i) composite scaling laws, (ii) small critical exponents τ associated with the power-law fragment-size distribution, and (iii) the typical pattern of cracks. The proposed computer simulations do not require numerical solutions of Newton's equations of motion, nor several additional assumptions normally used in discrete element models. The model is also able to predict some physical aspects which could be tested in new experiments of fragmentation of brittle systems.
NUCLEAR MATRIX ELEMENTS FOR DOUBLE BETA DECAY
Authors: SUHONEN JOUNI , KORTELAINEN MARKUS
Published: February 2008

The neutrinoless double beta (0νββ) decay of atomic nuclei plays a key role in the search for massive Majorana neutrinos and their mass scale. To extract the necessary information from the measured data the nuclear-structure effects have to be accounted for by computation of the associated nuclear matrix elements (NME's). In this article the NME's for the light-neutrino exchange mechanism are discussed. They are computed by using the proton-neutron quasiparticle random-phase approximation (pnQRPA). Recent developments in this field relate to the handling of the nucleon-nucleon short-range correlations and independent experimental probes of the wave functions relevant for the NME's.
TIME-DEPENDENT HARTREE-FOCK DESCRIPTION OF HEAVY IONS FUSION
Authors: SIMENEL CÉDRIC , AVEZ BENOÎT
Published: February 2008

A microscopic mean-field description of heavy ions fusion is performed in the framework of the Time-Dependent Hartree-Fock (TDHF) theory using a Skyrme interaction with the SLy 4d parametrization. A good agreement with experiments is obtained on the position of the fusion barriers for various total masses, mass asymmetries and deformations. The excitation function of the 16 O +208 Pb is overestimated by about 16% above the barrier. The restriction to an independent particles state in the mean-field dynamics prevents the description of sub-barrier fusion. Effect of transfer on fusion is discussed.
JACOBI SHAPE TRANSITIONS WITHIN THE LSD MODEL AND THE SKYRME-ETF APPROACH
Authors: BARTEL JOHANN , POMORSKI KRZYSZTOF
Published: February 2008

The "Modified Funny-Hills parametrisation" is used together with the Lublin-Strasbourg Drop Model to evaluate the stability of rotating nuclei. The Jacobi transition into triaxial shapes is studied. By a comparison with selfconsistent semiclassical calculations in the framework of the Extended Thomas-Fermi method, the validity of the present approach is demonstrated and possible improvements are indicated.
COUPLING OF SURFACE AND VOLUME DIPOLE OSCILLATIONS INC60MOLECULES
Authors: BRACK M. , WINKLER P. , MURTHY M. V. N.
Published: February 2008

We first give a short review of the "local-current approximation" (LCA), derived from a general variation principle, which serves as a semiclassical description of strongly collective excitations in finite fermion systems starting from their quantum-mechanical mean-field ground state. We illustrate it for the example of coupled translational and compressional dipole excitations in metal clusters. We then discuss collective electronic dipole excitations in C60molecules (Buckminster fullerenes). We show that the coupling of the pure translational mode ("surface plasmon") with compressional volume modes in the semiclasscial LCA yields semi-quantitative agreement with microscopic time-dependent density functional (TDLDA) calculations, while both theories yield qualitative agreement with the recent experimental observation of a "volume plasmon".
COLLECTIVE EXCITATIONS OF TRANSACTINIDE NUCLEI IN A SELF-CONSISTENT MEAN FIELD THEORY
Authors: PRÓCHNIAK L.
Published: February 2008

We applied the ATDHFB approach for study of properties of collective quadrupole states in several transactinide nuclei: 238 U , 240 Pu , 242 Pu , 246 Cm , 248 Cm , 250 Cf and 252 Cf . Calculated energies and B(E2) transition probabilities are in a reasonable agreement with experimental data. We present also results concerning superdeformed collective states in the second minimum of potential energy of the 240 Pu nucleus.
SADDLE-POINT SHAPES OF HEAVY AND SUPERHEAVY NUCLEI
Authors: SOBICZEWSKI A. , KOWAL M. , SHVEDOV L.
Published: February 2008

The potential energy of the heaviest nuclei is analyzed in a large deformation space. The main attention is given to shapes of these nuclei at their saddle point and to the comparison of these shapes with those at the ground state. The shapes are analyzed in a 10-dimensional deformation space. The analysis is performed within a macroscopic-microscopic approach. Even-even nuclei with proton number 98 ≤ Z ≤ 126 and neutron number 138 ≤ N ≤ 194 are considered.
SEMICLASSICAL DESCRIPTION OF EXOTIC NUCLEAR SHAPES
Authors: VIÑAS X. , CENTELLES M. , WARDA M.
Published: February 2008

Exotic nuclear structures such as bubbles and tori are analyzed through semiclassical extended Thomas-Fermi calculations with the Skyrme force SkM*. The variational equations for neutron and proton densities are solved fully self-consistently in spherical (bubbles) and cylindrical (tori) symmetries. The possible existence of bubble configurations in some astrophysical scenarios is discussed. The stability of toroidal structures against change of quadrupole moment is studied. A global minimum of the energy is found in heavy toroidal nuclei.
SEARCH FOR HYPERHEAVY TOROIDAL NUCLEAR STRUCTURES FORMED IN AU + AU COLLISIONS
Authors: SOCHOCKA A. , BENISZ A. , HACHAJ P. , NICOLIS N. G. , PŁANETA R. , STARYPAN Z.
Published: February 2008

We study the feasibility of an experimental observation of toroidal breakup configurations in Au + Au collisions using the CHIMERA multidetector system. BUU simulations indicate that the threshold energy for toroidal configuration is around 23 MeV/nucleon. The simulations of decay process using the ETNA code indicate the sensitivity of some observables to different studied break-up geometries.
COLLECTIVE BANDS IN SUPERDEFORMED NUCLEI
Authors: KVASIL J. , LO IUDICE N. , ANDREOZZI F. , PORRINO A. , KNAPP F.
Published: February 2008

The collective properties of excited superdeformed bands have been investigated in the framework of self-consistent cranked Nilsson plus quasiparticle random-phase approximation. The expected octupole nature of some bands observed recently in some nuclei has been confirmed by a comparative analysis of their E1 decays to the yrast band and of the anomalous behavior of their dynamical moment of inertia. It is also shown that the onset of supederformation affects considerably the structure of the giant resonances and greatly enhances the collectivity of the low-lying scissors mode.
CLUSTER RADIOACTIVITY OF TH ISOTOPES IN THE MEAN-FIELD HFB THEORY
Authors: ROBLEDO L. M. , WARDA M.
Published: February 2008

Cluster radioactivity is described as a very mass asymmetric fission process. The reflection symmetry breaking octupole moment has been used in a mean field HFB theory as leading coordinate instead of the quadrupole moment usually used in standard fission calculations. The procedure has been applied to the study of the "very mass asymmetric fission barrier" of several even-even Thorium isotopes. The masses of the emitted clusters as well as the corresponding half-lives have been evaluated on those cases where experimental data exist.
TENSOR FORMALISM FOR ROTATIONAL AND VIBRATIONAL NUCLEAR MOTIONS WITH DISCRETE SYMMETRIES: ROTATIONAL TERMS
Authors: GÓŹDŹ A. , MIŚKIEWICZ M. , DUDEK J.
Published: February 2008

The method of construction of nuclear collective Hamiltonians with discrete symmetries has been considered. The method allows to construct the collective Hamiltonians using O(3) tensors as building blocks. The formula for general form of the rotational reduced matrix elements is derived.
Peat slope failure in Ireland
Authors: Boylan N. , Jennings P. , Long M.
Published: February 2008

Recent peat slope failures in Ireland in the autumn of 2003 at Pollatomish, County Mayo and Derrybrien, County Galway have focused attention on such events. However, slope failures involving peat are not a recent phenomenon, and possible evidence of peat failures in Ireland has been identified as far back as the Early Bronze Age. This paper summarizes the issues surrounding peat slope failure in Ireland that would be of interest to an engineer or engineering geologist assessing this geohazard. The distribution of peat throughout Ireland, its formation, and its typical characteristic properties are discussed. A review of historical failures shows that there is a relationship between run-out distance and failure volume, and that the majority of the failures are clustered at slope angles between 4° and 8°. It seems that the risk of fatalities from peat slides is relatively low. The likely casual factors of peat slope failure are presented using examples including the recent failures at Pollatomish and Derrybrien, both of which have been investigated by the authors. Particular attention is paid to shear strength properties of peat and the applicability of traditional soil mechanics. Given the uncertainties that exist about peat strength, a cautious approach to slope stability assessment is advocated together with identification of potential causal factors to mitigate against this geohazard.
Engineering geomorphological input to ground models: an approach based on Earth systems
Authors: Griffiths J.S. , Stokes M.
Published: February 2008

The engineering geomorphological input to ground (‘geo’) models as part of standard site investigations tends to lack a systematic approach and is often restricted only to morphological mapping, the naming of landform features and usage of outdated morphoclimatic concepts. Ground models require more sophisticated geomorphological approaches and this is particularly apparent in regions such as Europe and North America where ground conditions can be strongly influenced by geomorphological processes linked to Quaternary or older environmental changes. Within this paper it is proposed that an ‘Earth system science’ approach underpinned by the ‘rock cycle’ can provide a framework for a systematic and more detailed geomorphological input into ground models. Such a framework lends itself to recognizing the fact that landscapes comprise multiple ‘fragments’ of process–response landforms, which, under contemporary conditions, may be: relict and inactive; relict but reactivated; subject to change once certain threshold events occur; or fully active. Using the rock cycle, a simple basis for landform categorization is outlined starting with a four-fold subdivision into structural, weathering, erosional and depositional landforms that allows the user to focus initially on the historical development of the landscape. Each category comprises a system of landforms that occur over standard geomorphological scales (pico-, nano-, micro-, meso-, macro- and mega-scale) as part of a process–response system. Macro-scale landforms are readily identifiable within a landscape, typically occurring as six principal terrain types: hills, ridges, mountains, plains, valleys and basins. These in turn comprise a series of meso-scale features that, once identified, can inform about the geomorphological processes that have resulted in their formation. The geomorphological input into ground models benefits primarily from recognition of these meso-scale landforms and the processes responsible for their formation, although smaller-scale landforms may have importance for specific engineering structures.
Thermogenic effect of triiodothyroacetic acid at low doses in rat adipose tissue without adverse side effects in the thyroid axis
Authors: Medina-Gomez G. , Calvo R. M. , Obregon M.-J.
Published: February 2008

Triiodothyroacetic acid (TRIAC) is a physiological product of triiodothyronine (T3) metabolism, with high affinity for T3nuclear receptors. Its interest stems from its potential thermogenic effects. Thus this work aimed 1) to clarify these thermogenic effects mediated by TRIAC vs. T3in vivo and 2) to determine whether they occurred predominantly in adipose tissues. To examine this, control rats were infused with equimolar T3or TRIAC doses (0.8 or 4 nmol·100 g body wt−1·day−1) or exposed for 48 h to cold. Both T3doses and only the highest TRIAC dose inhibited plasma and pituitary thyroid-stimulating hormone (TSH) and thyroxine (T4) in plasma and tissues. Interestingly, the lower TRIAC dose marginally inhibited plasma T4. T3infusion increased plasma and tissue T3in a tissue-specific manner. The highest TRIAC dose increased TRIAC concentrations in plasma and tissues, decreasing plasma T3. TRIAC concentrations in tissues were <10% those of T3. Under cold exposure or high T3doses, TRIAC increased only in white adipose tissue (WAT). Remarkably, only the lower TRIAC dose activated thermogenesis, inducing ectopic uncoupling protein (UCP)-1 expression in WAT and maximal increases in UCP-1, UCP-2, and lipoprotein lipase (LPL) expression in brown adipose tissue (BAT), inhibiting UCP-2 in muscle and LPL in WAT. TRIAC, T3, and cold exposure inhibited leptin secretion and mRNA in WAT. In summary, TRIAC, at low doses, induces thermogenic effects in adipose tissues without concomitant inhibition of TSH or hypothyroxinemia, suggesting a specific role regulating energy balance. This selective effect of TRIAC in adipose tissues might be considered a potential tool to increase energy metabolism.
Endogenous sodium pump inhibitors and age-associated increases in salt sensitivity of blood pressure in normotensives
Authors: Anderson David E. , Fedorova Olga V. , Morrell Christopher H. , Longo Dan L. , Kashkin Vladimir A. , Metzler Jessica D. , Bagrov Alexei Y. , Lakatta Edward G.
Published: February 2008

Factors that mediate increases in salt sensitivity of blood pressure with age remain to be clarified. The present study investigated 1) the effects of high-NaCl intake on two Na pump inhibitors, endogenous ouabain (EO) and marinobufagenin (MBG), in middle-aged and older normotensive Caucasian women; and 2) whether individual differences in EO and MBG are linked to variations in sodium excretion or salt sensitivity. A change from 6 days of a lower (0.7 mmol·kg−1·day−1)- to 6 days of a higher (4 mmol·kg−1·day−1)-NaCl diet elicited a sustained increase in MBG excretion that directly correlated with an increase in the fractional Na excretion and was inversely related to age and to an age-dependent increase in salt sensitivity. In contrast, EO excretion increased only transiently in response to NaCl loading and did not vary with age or correlate with fractional Na excretion or salt sensitivity. A positive correlation of both plasma and urine levels of EO and MBG during salt loading may indicate a casual link between two Na pump inhibitors in response to NaCl loading, as observed in animal models. A linear mixed-effects model demonstrated that age, dietary NaCl, renal MBG excretion, and body mass index were each independently associated with systolic blood pressure. Thus, a sustained increase in MBG in response to acutely elevated dietary NaCl is inversely linked to salt sensitivity in normotensive middle-aged and older women, and a relative failure of MBG elaboration by these older persons may be involved in the increased salt sensitivity with advancing age.
Role of Interneuron Diversity in the Cortical Microcircuit for Attention
Authors: Buia Calin I. , Tiesinga Paul H.
Published: February 2008

Receptive fields of neurons in cortical area V4 are large enough to fit multiple stimuli, making V4 the ideal place to study the effects of selective attention at the single-neuron level. Experiments have revealed evidence for stimulus competition and have characterized the effect thereon of spatial and feature-based attention. We developed a biophysical model with spiking neurons and conductance-based synapses. To account for the comprehensive set of experimental results, it was necessary to include in the model, in addition to regular spiking excitatory (E) cells, two types of interneurons: feedforward interneurons (FFI) and top-down interneurons (TDI). Feature-based attention was mediated by a projection of the TDI to the FFI, stimulus competition was mediated by a cross-columnar excitatory connection to the FFI, whereas spatial attention was mediated by an increase in activity of the feedforward inputs from cortical area V2. The model predicts that spatial attention increases the FFI firing rate, whereas feature-based attention decreases the FFI firing rate and increases the TDI firing rate. During strong stimulus competition, the E cells were synchronous in the beta frequency range (15–35 Hz), but with feature-based attention, they became synchronous in the gamma frequency range (35–50 Hz). We propose that the FFI correspond to fast-spiking, parvalbumin-positive basket cells and that the TDI correspond to cells with a double-bouquet morphology that are immunoreactive to calbindin or calretinin. Taken together, the model results provide an experimentally testable hypothesis for the behavior of two interneuron types under attentional modulation.
Recording Temperature Affects the Excitability of Mouse Superficial Dorsal Horn Neurons, In Vitro
Authors: Graham B. A. , Brichta A. M. , Callister R. J.
Published: February 2008

Superficial dorsal horn (SDH) neurons in laminae I–II of the spinal cord play an important role in processing noxious stimuli. These neurons represent a heterogeneous population and are divided into various categories according to their action potential (AP) discharge during depolarizing current injection. We recently developed an in vivo mouse preparation to examine functional aspects of nociceptive processing and AP discharge in SDH neurons and to extend investigation of pain mechanisms to the genetic level of analysis. Not surprisingly, some in vivo data obtained at body temperature (37°C) differed from those generated at room temperature (22°C) in spinal cord slices. In the current study we examine how temperature influences SDH neuron properties by making recordings at 22 and 32°C in transverse spinal cord slices prepared from L3–L5 segments of adult mice (C57Bl/6). Patch-clamp recordings (KCH3SO4 internal) were made from visualized SDH neurons. At elevated temperature all SDH neurons had reduced input resistance and smaller, briefer APs. Resting membrane potential and AP afterhyperpolarization amplitude were temperature sensitive only in subsets of the SDH population. Notably, elevated temperature increased the prevalence of neurons that did not discharge APs during current injection. These reluctant firing neurons expressed a rapid A-type potassium current, which is enhanced at higher temperatures and thus restrains AP discharge. When compared with previously published whole cell recordings obtained in vivo (37°C) our results suggest that, on balance, in vitro data collected at elevated temperature more closely resemble data collected under in vivo conditions.
Similar Properties of Transient, Persistent, and Resurgent Na Currents in GABAergic and Non-GABAergic Vestibular Nucleus Neurons
Authors: Gittis Aryn H. , du Lac Sascha
Published: February 2008

Sodium currents in fast firing neurons are tuned to support sustained firing rates >50–60 Hz. This is typically accomplished with fast channel kinetics and the ability to minimize the accumulation of Na channels into inactivated states. Neurons in the medial vestibular nuclei (MVN) can fire at exceptionally high rates, but their Na currents have never been characterized. In this study, Na current kinetics and voltage-dependent properties were compared in two classes of MVN neurons with distinct firing properties. Non-GABAergic neurons (fluorescently labeled in YFP-16 transgenic mice) have action potentials with faster rise and fall kinetics and sustain higher firing rates than GABAergic neurons (fluorescently labeled in GIN transgenic mice). A previous study showed that these neurons express a differential balance of K currents. To determine whether the Na currents in these two populations were different, their kinetics and voltage-dependent properties were measured in acutely dissociated neurons from 24- to 40-day-old mice. All neurons expressed persistent Na currents and large transient Na currents with resurgent kinetics tuned for fast firing. No differences were found between the Na currents expressed in GABAergic and non-GABAergic MVN neurons, suggesting that differences in properties of these neurons are tuned by their K currents.
Indications of the Mechanisms Involved in Improved Sperm Parameters by Zinc Therapy
Authors: Omu A.E. , Al-Azemi M.K. , Kehinde E.O. , Anim J.T. , Oriowo M.A. , Mathew T.C.
Published: February 2008

Objective: To determine possible indications of the mechanisms involved in improved sperm parameters by zinc therapy in asthenozoospermic men. Subjects and Methods: Forty-five men with asthenozoospermia (≧40% immotile sperm) were randomized into four therapy groups: zinc only: n = 11; zinc + vitamin E: n = 12 and zinc + vitamins E + C: n = 14 for 3 months, and non-therapy control group: n = 8. Semen analysis was done according to WHO guidelines. Malone dialdehyde, tumour necrosis factor-α (TNF-α), total antioxidant capacity, superoxide dismutase (SOD) and glutathione peroxidase were determined in the semen and serum. Antisperm antibodies IgG, IgM and IgA were evaluated by immunobeads. Sperm chromatin integrity was determined by acid denaturation by acridine orange and sperm apoptosis by light and electron microscopy. The effect of zinc on in vitro induced sperm oxidative stress by NADH was evaluated. Results: Asthenozoospermia was significantly associated with oxidative stress with higher seminal malone dialdehyde (8.8 vs. 1.8 mmol/l, p < 0.001) and TNF-α (60 vs. 12 pg/l, p < 0.001), and low total antioxidant capacity (1.8 vs. 8.4, p < 0.01), SOD (0.8 vs. 3.1, p < 0.01) and glutathione peroxidase (1.6 vs. 4.2, p < 0.05), compared to normozoospermia. Zinc therapy alone, in combination with vitamin E or with vitamin E + C were associated with comparably improved sperm parameters with less oxidative stress, sperm apoptosis and sperm DNA fragmentation index (DFI). On the whole, there was no difference in the outcome measures between zinc only and zinc with vitamin E and combination of vitamins E + C. In the in vitro experiment zinc supplementation resulted in significantly lower DFI (14–29%, p < 0.05) compared to zinc deficiency. Conclusion: Zinc therapy reduces asthenozoospermia through several mechanisms such as prevention of oxidative stress, apoptosis and sperm DNA fragmentation.
Aseptic Meningitis among Children in Kuwait
Authors: Husain Entesar H. , Bahbahani Esmaeel , Al-Shawaf Faisal , El-Nabi Mamdooh Hasab , Shafiq Majdi Hilmi , Al-Ateeqi Nahid , Talib Atef Abo
Published: February 2008

Objective: To describe the epidemiology, clinical features, and the morbidity caused by aseptic meningitis in children in Kuwait. Subjects and Method: A multicenter retrospective study of previously healthy children hospitalized with a diagnosis of aseptic meningitis in the period 2001–2003 was carried out. Results: There were 172 children with the diagnosis of meningitis based on changes in the cerebrospinal fluid. Aseptic meningitis was diagnosed in 86 (50%) of the cases; their mean age was 3.2 ± 3.8 years. There were two peaks of cases, one during the months of May and June and the other in November/December. Older children (≧5 years) presented more frequently with signs and symptoms suggestive of meningeal irritation than younger children (<5 years) (p ≤ 0.01). The median duration of hospitalization was 7 days. The majority (n = 56, 65%) received a 7- to 10-day course of antibiotics despite negative cerebrospinal fluid cultures. Six (7%) hospitalized children had complications: 3 had convulsions, 2 were ventilated, and 1 had motor palsy. Intensive care unit admission was necessary in 3. All the children were discharged home without sequelae. There were no mortalities in the study group. Conclusions: Aseptic meningitis among children in Kuwait is a major cause of morbidity and requires prolonged hospitalization. The complication rate is low and there were no sequelae or mortality among the studied cohort.
Effects of Cyanocobalamin on Immunity in Patients with Pernicious Anemia
Authors: Erkurt Mehmet Ali , Aydogdu Ismet , Dikilitaş Mustafa , Kuku Irfan , Kaya Emin , Bayraktar Nihayet , Ozhan Onur , Ozkan Ibrahim , Sönmez Ahmet
Published: February 2008

Objective: The aim of the study was to evaluate the role of vitamin B12 in patients with pernicious anemia. Materials and Methods: This study was conducted prospectively at the Turgut Özal Medical Center, Department of Hematology, between April and November 2002. Absolute numbers and ratio of the surface antigens of T and B lymphocyte subgroups, CD4/CD8 ratio were calculated in order to evaluate changes in leukocyte and lymphocyte numbers; natural killer (NK) cell count, serum C3, C4, and levels of immunoglobulins G, A, and M were also measured to evaluate vitamin B12 effect on immunity. Values obtained before treatment with cyanocobalamin were compared with those found during peak reticulocyte count. Results: In vitamin B12-deficient patients, absolute numbers of CD4+ and especially CD8+ lymphocytes were found to be decreased; CD4/CD8 ratio increased, and NK cell activity was depressed. After cyanocobalamin treatment, absolute numbers and percentage of lymphocyte subgroups were elevated. Increased CD4/CD8 ratio and depressed NK cell activity were restored and levels of C3, C4, and immunoglobulins were elevated. Conclusion: These findings suggest that vitamin B12 has important immunomodulatory effects on cellular immunity, and abnormalities in the immune system in pernicious anemia are restored by vitamin B12 replacement therapy.
Effects of Cigarette Smoking on Hematological Parameters and von Willebrand Factor Functional Activity Levels in Asymptomatic Male and Female Arab Smokers
Authors: Al-Awadhi Anwar M. , AlFadhli Suad M. , Mustafa Nada Y. , Sharma Prem N.
Published: February 2008

Objectives: This study aimed at determining the effects of cigarette smoking based on gender, on several hematological parameters and von Willebrand factor protein in the asymptomatic Arab population of Kuwait. Subjects and Methods: Ninety-two subjects participated in this study: 55 males (31 smokers and 24 nonsmokers) and 37 females (18 smokers and 19 nonsmokers). Complete blood count results were obtained using Beckman Coulter Hematology Analyzer. Von Willebrand factor functional activity was determined using an enzyme-linked immunoassay-based test in which anti-von Willebrand factor IgG monoclonal antibody was used that recognizes a functional epitope of the protein. The coagulation profile was obtained using ACL® 9000 coagulation analyzer. Results: Male smokers had significantly higher levels of white blood cell count (p = 0.03) and von Willebrand factor protein levels (p = 0.029), and a significantly shorter thrombin time (p = 0.019) than nonsmokers. Smoking did not appear to affect any of the parameters analyzed in females as no significant difference was found between smokers and nonsmokers (p > 0.05). Conclusion: Our results showed that smoking affected white blood cell count and von Willebrand factor levels in males and not in females, and as such could be potential markers for smoking-induced endothelial damage in asymptomatic Arab male smokers.
The Use of Lithium Carbonate in the Preparation for Definitive Therapy in Hyperthyroid Patients
Authors: Akin Fulya , Yaylali Guzin Fidan , Bastemir Mehmet
Published: February 2008

Objective: The aim of this study was to elucidate the effectiveness of lithium carbonate prior to thyroidectomy or radioiodide therapy in patients with thyrotoxicosis. Subjects and Methods: Lithium carbonate was used as preoperative preparation or radioiodide therapy in 5 patients with Graves’ disease and in 1 patient with toxic multinodular goiter because of side effects of thionamide in 5 patients and ineffectiveness of antithyroid medication in the remaining patient. Results: All 6 patients had a benign course following treatment without thyroid storm. No adverse effects or complications of lithium carbonate were observed. Conclusion: This report shows that lithium carbonate can be safely used preoperatively or prior to radioiodide therapy in circumstances where antithyroid medications are contraindicated and are ineffective in obtaining an euthyroid status.
Fetal Cytomegalovirus Infection Associated with Cerebral Hemorrhage, Hydrops Fetalis, and Echogenic Bowel: Case Report
Authors: Tongsong Theera , Sukpan Kornkanok , Wanapirak Chanane , Phadungkiatwattna Podjanee
Published: February 2008

We describe some fetal ultrasound findings associated with intrauterine cytomegalovirus (CMV) infection. We report a 38-year-old gravida 3, para 2 at 16 weeks of gestation who underwent ultrasound examination for anomaly screening. The scan revealed an extensive irregular echogenic area in the fetal brain, especially at the level of lateral ventricles, suggestive of intraventricular and cerebral hemorrhage. Cardiomegaly, hepatomegaly, and mild ascites as well as an echogenic bowel were demonstrated. Abnormal chromosomes and hemoglobin Bart disease were excluded by analysis of fetal blood. Follow-up ultrasound at 20 weeks of gestation showed frank hydrops fetalis, and termination of the pregnancy was performed based on the couple’s decision, giving stillbirth to a male fetus weighing 450 g. Autopsy findings showed intracerebral hemorrhage (right cerebral hemisphere) and hydrops fetalis with hepatosplenomegaly. Microscopic investigation showed typical changes of CMV infection in several organs, including brain, thyroid gland, lung, liver, kidney, heart, pancreas, and placenta. Sonographically, the combination of hydrops fetalis, cerebral hemorrhage, and hyperechoic bowel should raise the possibility of a CMV infection, particularly in cases with no obvious cause of hydrops fetalis.
Risk of Chromosome Abnormalities in the Presence of Bilateral or Unilateral Choroid Plexus Cysts
Authors: Beke Artúr , Barakonyi Emese , Belics Zorán , Joó József G. , Csaba Ákos , Papp Csaba , Tóth-Pál Ernő , Papp Zoltán
Published: February 2008

Objectives: To evaluate the rate of chromosome abnormalities in cases of uni- and bilateral choroid plexus cysts (CPCs). Methods: A total of 10,875 ultrasound (US) examinations were performed in the second trimester, and 435 cases with CPC (4%) were found. After genetic counseling, 45 patients decided not to undergo karyotyping. The authors performed a chromosome analysis in 390 cases of CPCs. Results: The total risk of chromosome abnormalities was 3.59% (n = 14) and risk of trisomies was 2.05% (n = 8). Trisomy 18 was found in 6 cases (1.54%), trisomy 21 in 1 case (0.26%), and trisomy 9 in 1 case (0.26%). The risk of 45,X karyotype was 0.77% (n = 3). One case of 47,XXY karyotype and 2 cases with other chromosome abnormalities were found. In 212 unilateral cases there were 7 with chromosome abnormalities (3.3%). In 178 bilateral cases there were 7 with abnormal karyotypes (3.93%). The CPC was associated with additional fetal US anomalies (with or without polyhydramnios/oligohydramnios) in 112 cases; chromosome abnormalities were detected in 4 cases (3.57%). 66 cases were associated with polyhydramnios/oligohydramnios but not with other fetal US anomalies; 3 cases of abnormal karyotypes were found (4.55%). The CPC was isolated in 212 cases and 7 cases were associated with chromosome disorders (3.3%). Conclusions: US plays an important role in prenatal diagnostics. Further genetic counseling is recommended in cases with CPCs.
Feticide Does Not Modify Duration of Labor Induction in Cases of Medical Termination of Pregnancy
Authors: Silva Luciana Vivas , Cecatti José Guilherme , Pinto e Silva João Luiz , Amaral Eliana , Barini Ricardo
Published: February 2008

Objectives: To compare the general characteristics and clinical outcome of women who underwent medical termination of pregnancy preceded or not by feticide. Methods: A total of 146 women of diverse gestational ages, who had received a sonographic or genetic diagnosis of fetal abnormality incompatible with postnatal life and chose to legally terminate their pregnancy, had labor induced following feticide (n = 82) or without having feticide performed (n = 64). Results: The number of obstetrical procedures was higher (p = 0.001) in the feticide group. Time of labor induction and complications were similar in both groups. Conclusion: Feticide does not alter the clinical obstetrical course of women undergoing medical termination of pregnancy, and poses no risk to maternal health regardless of gestational age.
Analysis of Factors Influencing the Ultrasonic Fetal Weight Estimation
Authors: Heer Ivo Markus , Kümper Carolin , Vögtle Nadin , Müller-Egloff Susanne , Dugas Martin , Strauss Alexander
Published: February 2008

Objective: The aim of our study was the evaluation of sonographic fetal weight estimation taking into consideration 9 of the most important factors of influence on the precision of the estimation. Methods: We analyzed 820 singleton pregnancies from 22 to 42 weeks of gestational age. We evaluated 9 different factors that potentially influence the precision of sonographic weight estimation (time interval between estimation and delivery, experts vs. less experienced investigator, fetal gender, gestational age, fetal weight, maternal BMI, amniotic fluid index, presentation of the fetus, location of the placenta). Finally, we compared the results of the fetal weight estimation of the fetuses with poor scanning conditions to those presenting good scanning conditions. Results: Of the 9 evaluated factors that may influence accuracy of fetal weight estimation, only a short interval between sonographic weight estimation and delivery (0–7 vs. 8–14 days) had a statistically significant impact. Conclusion: Of all known factors of influence, only a time interval of more than 7 days between estimation and delivery had a negative impact on the estimation.
Human Placental Growth Hormone Is Increased in Maternal Serum in Pregnancies Affected by Down Syndrome
Authors: Papadopoulou Eleftheria , Sifakis Stavros , Giahnakis Emmanuel , Fragouli Yvoni , Karkavitsas Nikolaos , Koumantakis Eugenios , Kalmanti Maria
Published: February 2008

Objective: To evaluate the relationship between maternal serum levels of human placental growth hormone (hPGH) and fetal Down syndrome at gestational midtrimester. Methods: We retrospectively analyzed samples of serum from 21 women with Down syndrome pregnancies detected at gestational midtrimester. The samples were obtained at 16–23 weeks’ gestation during amniocentesis for fetal karyotyping. Sixty-two serum samples were used as controls, which were obtained at 16–23 weeks’ gestation from women with singleton, uncomplicated pregnancies, who gave birth to healthy neonates with a birth weight appropriate for gestational age. The hPGH levels were measured by a solid-phase immunoradiometric assay using 2 different epitopes. Results: The median hPGH values in the serum of the Down-syndrome-affected pregnancies were significantly higher (p < 0.05) than those of the normal pregnancies at 16–23 weeks’ gestation: the median value in the serum was 9.4 ng/ml (5th to 95th percentiles = 1.49–39.03) versus 4.7 ng/ml (0.53–7.88). Conclusion: The hPGH levels in maternal serum were found to be higher at 16–23 weeks’ gestation in pregnancies affected by fetal Down syndrome. Further investigation is needed to examine if maternal serum hPGH could be used as an additional marker in prenatal screening of Down syndrome at gestational midtrimester.
Fetal Manifestation of the Fine-Lubinsky Syndrome
Authors: Schoner Katharina , Bald Rainer , Fritz Barbara , Rehder Helga
Published: February 2008

Objectives: We report on a female fetus of 24 weeks gestational age with Fine-Lubinsky syndrome (FLS), representing the 7th case published so far. Methods: Prenatal ultrasound was performed at 22+1 weeks of gestation and thorough postmortem examination was made after termination of pregnancy. Results: The diagnosis of FLS in the fetus was based on characteristic features that were already apparent in early prenatal life, such as growth deficiency, brachycephaly, flat face with associated dysmorphic signs, microstomia and cataract, while deafness and mental retardation, which are syndrome-specific functional disorders and evident only postnatally, could not be taken into account. Conclusions: This case demonstrates the diagnostic problems in fetal syndromology if syndrome-specific features are not yet recognizable and additional complications occur that had not been observed in this disorder.
Adverse Outcome of Pregnancies with Extremely High Levels of Maternal Serum Human Chorionic Gonadotropin
Authors: Sharony Reuven , Itzhaky Deganit , Amiel Aliza , Hershko Anat , Grinshpoon Yulia , Fejgin Moshe
Published: February 2008

Background: The associated risk of elevated levels of maternal serum human chorionic gonadotropin (MShCG) with pregnancy complications was reported in many studies. However, the outcome of pregnancies with extremely high levels of MShCG was never independently studied. Methods: We report on 6 out of 45,990 studied patients with extremely high levels of MShCG (>15 multiples of the medians) analyzed during the second trimester. Results: Although our patient population was composed of more Jewish than Arab pregnant women, all those patients were Arabs. Overall, the prognosis of those pregnancies was poor. In 1 case, an antepartum fetal death occurred, 2 had premature deliveries (one of the newborns had severe failure to thrive), and 2 delivered small for gestational age babies. In 5 of these 6 cases, no specific diagnosis was established. One case was complete hydatidiform mole with a coexisting normal fetus. Conclusions: We recommend that these patients undergo counseling in which the predicted outcome will be described. In addition, a follow-up of high-risk pregnancy should be implemented: sonographic evaluation should be performed, initially to rule out a molar gestation. The patients should then be followed for growth restriction and they should be monitored to rule out other pregnancy complications such as premature labor and antepartum fetal death. Finally, the overrepresentation of Arabs among our affected patients raises the question of a possible genetic tendency for increased MShCG levels especially in the extreme level group.
Fetal Cardiocentesis: A Review of Indications, Risks, Applications and Technique
Authors: Sarno, Jr. Albert P. , Wilson R. Douglas
Published: February 2008

Objectives: To review the indications, applications and technique of fetal cardiocentesis. Methods: Review of published case reports and case series of fetal cardiocentesis utilizing the PubMed search engine of the National Library of Medicine. Results: Case reports and case series demonstrate that fetal cardiocentesis may be an alternative method by which to facilitate prenatal diagnosis, intravascular therapy, multifetal and selective fetal reduction and in utero therapy of congenital heart disease. However, procedure-associated risk is higher than with cordocentesis and may limit use of this procedure. Conclusions: Fetal cardiocentesis may be a reasonable option to obtain fetal intravascular access and facilitate therapeutic interventions when cordocentesis fails or is not feasible. However, expected benefit must clearly outweigh the procedure-associated risk.
Interleukin-6 Is a Better Predictor of Mortality as Compared to C-Reactive Protein, Homocysteine, Pentosidine and Advanced Oxidation Protein Products in Hemodialysis Patients
Authors: Pachaly Maria A. , do Nascimento Marcelo M. , Suliman Mohamed E. , Hayashi Shirley Y. , Riella Miguel C. , Manfro Roberto C. , Stenvinkel Peter , Lindholm Bengt
Published: February 2008

Inflammatory markers predict mortality in hemodialysis (HD) patients, whereas a possible association between oxidative stress (OS) markers and survival is less clear. We assessed the impact on all-cause mortality of baseline inflammatory [high-sensitivity C-reactive protein and interleukin-6 (IL-6)] and OS markers (advanced oxidation protein products, pentosidine, homocysteine) in 112 HD patients. We found no significant correlations between inflammatory and OS markers. During the 5.5 years of follow-up, 51 patients died. In a Kaplan-Meier analysis, the survival rate was reduced in patients with IL-6 higher than the median (IL-6 >4.2 pg/ml) (log- rank = 6.47; p = 0.01), in diabetics (log-rank = 12.26; p = 0.0005) and in older patients (log-rank = 11.22; p = 0.0008). Moreover, in Cox analysis only IL-6 and age were independently associated with mortality. We conclude that in this group of prevalent Brazilian HD patients, IL-6 was a better predictor of survival than other inflammatory and OS markers.