bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Basic Heart Rate and Sex on Heart Rate Turbulence in Healthy Subjects
Authors: SCHWAB JÖRG O. , EICHNER GERRIT , VEIT GUDRUN , SCHMITT HEIKO , LEWALTER THORSTEN , LÜDERITZ BERNDT
Published: December 2004

Acceleration and deceleration of the heart rate after the occurrence of a ventricular premature complex is characterized as heart rate turbulence (HRT). Two parameters quantify heart rate turbulence: onset and slope. The physiological properties have not been clarified in a large cohort of persons yet. This study evaluated properties of HRT, and focused on the influence of basic heart rate and sex on HRT. Using a special protocol, 95 persons were studied prospectively. HRT and its physiological properties were determined in 95 persons using Holter ECGs. The authors found 24% with a turbulence onset 0% and 5% with a turbulence slope <2.5 ms/RRI. Mean heart rate during Holter differed significantly between women and men (745 vs 817 ms, P < 0.0001). A linear, weighted regression model revealed that an increased heart rate before a ventricular premature complex is associated with a decreased turbulence onset (P < 0.0001). Turbulence slope was attenuated by basic heart rate only in men (P = 0.0022). On the contrary, the study detected no influence of the basic heart rate on turbulence slope in women (P = 0.0015 for the comparison between women and men). Basic heart rate and sex show an influence on HRT and should be considered when using HRT for noninvasive risk stratification.
Recording Atrial Monophasic Action Potentials Using Standard Pacemaker Leads:
Authors: CHRIST TORSTEN , RAUWOLF THOMAS , BRAUN MARTIN , DOBREV DOBROMIR , RAVENS URSULA , STRASSER RUTH H.
Published: December 2004

AF leads to electrophysiological changes, but it is not known if similar alterations also appear before the onset of the first episode of AF because invasive electrophysiological studies are not justified in otherwise symptom‐free patients. To address this question requires a safe method of obtaining atrial electrophysiological parameters at no extra risk or discomfort for the patient. The aim of this study was to test if recording of monophasic action potentials (MAPs) is feasible during pacemaker implantation. The study included 22 patients undergoing pacemaker implantation for symptomatic bradycardia without any history of AF. Using a custommade amplifier and a minor modification of the routine procedure for intraoperatively measured P waves, atrial electrograms could be recorded using a standard active pacemaker lead. MAP‐like electrograms were obtained in 15 patients. MAP amplitude was 2.6 ± 0.3 mV, mean action potential duration was 316 ± 12 ms at a spontaneous heart rate of 67.2 ± 3.2 beats/min. MAP duration was decreased when atria were stimulated at shorter cycle lengths (249 ± 12 ms at 150 beats/min, P <0.05 vs sinus rhythm). In about two thirds of patients undergoing pacemaker implantation, recording of MAP‐like electrograms was feasible with only minor modification of the atrial electrogram recording technique. The method should allow screening patients for electrophysiological alterations even before the onset of AF.
Preliminary Results with the Microwave‐Modified Maze III Procedure for the Treatment of Chronic Atrial Fibrillation
Authors: HURLÉ AQUILINO , IBÁÑEZ ALICIA , PARRA JOSÉ M. , MARTÍNEZ JUAN G.
Published: December 2004

Between February 2003 and January 2004 a microwave‐modified Maze III procedure was performed as an associated procedure in nine patients in chronic atrial fibrillation undergoing surgery for heart valve disease. Clinical follow‐up was carried out in all survivors, and an echocardiographic assessment done in all those in sinus rhythm, during the first week of February 2004. There were six women and three men with a mean age of 60 ± 9.4 years. Their rhythm at the end of surgery was sinus in 2 patients, nodal in 4, and complete AV block in 3. One patient died in hospital and there patients had no other complications related to the procedure. By the time of hospital discharge, four patients were in sinus rhythm and four were in atrial fibrillation. After a mean follow‐up of 5.2 ± 3.3 months there were no late deaths, 5 patients were in sinus rhythm, 1 required a permanent pacemaker in DDDR mode for persistent sinus bradycardia, and 2 remained in atrial fibrillation. Echocardiographic assessment, performed at a mean of 4.9 ± 2.5 months after surgery in all patients in sinus rhythm or with a pacemaker, demonstrated biatrial contraction in five patients. The Cox‐Maze III procedure can be performed safely and with good results using microwave energy instead of the conventional “cut and sew” technique.
Nonvolcanic Tremors Deep Beneath the San Andreas Fault
Authors: Nadeau Robert M. , Dolenc David
Published: December 2004

We have discovered nonvolcanic tremor activity (i.e., long-duration seismic signals with no clear
P
or
S
waves) within a transform plate boundary zone along the San Andreas Fault near Cholame, California, the inferred epicentral region of the 1857 Fort Tejon earthquake (moment magnitude ~7.8). The tremors occur between 20 to 40 kilometers' depth, below the seismogenic zone (the upper ~15 kilometers of Earth's crust where earthquakes occur), and their activity rates may correlate with variations in local earthquake activity.
Coordination arrays  Synthesis and characterization of tetranuclear complexes of grid-type
Authors: Hanan Garry S , Volkmer Dirk , Lehn Jean-Marie
Published: December 2004

A series of tetranuclear metal complexes of grid-type consisting of four bis-tridentate ligands and four divalent transition metal ions were synthesized and characterized. The 1H NMR spectra of diamagnetic complexes containing Zn(II), Cd(II), Fe(II), and Ru(II) was correlated to the radius of the metal ion. The UVvis and electrochemical results indicated that the bridging ligand π* orbital and the dπ metal orbital are stabilized by complexation of more than one metal ion. Furthermore, the Co(II) and Fe(II) grids exhibit metalmetal interaction mediated by the bis-tridentate ligands as indicated by electrochemical and spectroscopic methods. These results provide guidelines for the design of larger grids bearing several metal centres in a square arrangement, which also represent potential components of molecular electronic devices.Key words: complexes with nitrogen ligands, octahedral metal ions, self-assembly, supramolecular chemistry.
Tetraphosphinitoresorcinarene complexes  A new structural form of a rhodium(I) diphosphine complex
Authors: Eisler Dana J , Puddephatt Richard J
Published: December 2004

Tetrakis(diphenylphosphinito)resorcinarene ligands are shown to react with [Rh2(µ-Cl)2(CO)4] to give tetrarhodium(I) complexes in which there are two dirhodium units, each having the unprecedented structure syn-[Rh2(µ-Cl)2(CO)2P2], P = phosphinite donor.Key words: rhodium, resorcinarene, tetraphosphinite, carbonyl.
A Raman study of aqueous DMF and DMA solutions at low temperatures
Authors: Tomikawa K , Kanno H , Kimoto H
Published: December 2004

Hydrogen bonding in aqueous N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) solutions was studied by Raman spectroscopy of the OH-stretching spectra of water as functions of solute concentration and temperature (from 50 to 50 °C). The Raman spectra were decomposed successfully into two components (the low- and high-frequency components). The peak area ratio of the low-frequency component to the high-frequency component increases exponentially with decreasing temperature. The frequency of the low-frequency component decreases linearly with lowering temperature down to 50 °C at all solute concentrations (solute mol fraction from 0.3 to 0.7). It is shown that the hydrogen bonds in the clathrate structures around DMA molecules are stronger than those around DMF molecules.Key words: Raman spectrum, DMF, DMA, aqueous solution, low temperature.
Insertion of acetone molecules in the nanostructured tunnels of palygorskite
Authors: Kuang Wenxing , Detellier Christian
Published: December 2004

The insertion of acetone molecules in the nanostructured tunnels of palygorskite (PFl-1) was studied by thermal gravimetric analysis connected with mass spectrometry and 29Si and 13C solid-state NMR techniques. In comparison with palygorskite, new weight losses appear at 130 and 340 °C for palygorskite previously heated at 150 °C for 20 h then exposed to acetone for a week. Two types of water molecules occupy the palygorskite tunnels: weakly bound zeolitic water and structural water molecules coordinated to Mg(II) cations at the edge of the octahedral sheets. Acetone molecules that intercalate in the nanostructured tunnels replace the zeolitic water and are H-bonded to structural water. The mass loss at 130 °C is accounted for by the release of structural water and acetone. The loss at 340 °C is due to the release of acetone molecules that coordinate directly to terminal cations in the nanostructured tunnels and to residual structural water. A nanostructured hybrid material, with a structure similar to the parent palygorskite, can be formed through the direct coordination of acetone molecules to the terminal cationic coordination sites in the nanostructured tunnels of palygorskite. There is evidence for the fixation of two different types of acetone on palygorskite: mobile acetone molecules on the external surface and acetone molecules more rigidly fixed inside the nanotunnels. The former ones are detected by the 13C magic-angle spinning NMR experiment and can be easily removed by gentle heating at 60 °C, while the latter ones are detected by 13C cross-polarization magic-angle spinning NMR. It is also demonstrated that nearly complete recovery of the original structure is achieved by exposing palygorskite previously dehydrated at 150 or 300 °C to acetone vapor at room temperature. Key words: insertion, intercalation, nanostructured tunnels, palygorskite, acetone, nanocomposite materials, nanohybrid.
A solid-state NMR investigation of orexin-B
Authors: Bernard Guy M , Miskolzie Mark , Kotovych George , Wasylishen Roderick E
Published: December 2004

Some key aspects of the secondary structure of solid orexin-B, a 28 amino-acid peptide, have been investigated by solid-state NMR spectroscopy. The 13C15N dipolar coupling between the carbonyl carbon of Leu11 and the nitrogen of Leu15, as determined by rotational echo double resonance (REDOR) experiments, is 35 Hz, indicating that these nuclei are separated by approximately 4.5 Å. This distance is consistent with the α-helical structure determined for this segment of orexin-B by solution NMR measurements. REDOR measurements of the dipolar coupling between the carbonyl carbon of Ala17 and the nitrogen of Ala22 support the contention in an earlier solution NMR study that a bend exists between the two α helices of orexin-B. However, in the solid state the internuclear distance (6.4 Å) is significantly greater than that observed for orexin-B in aqueous solution. In addition to the distance measurements, the principal components of the amide carbonyl carbon chemical shift (CS) tensors for Leu11 and Ala17 and of the amide nitrogen CS tensors for Leu15 and Ala22 are reported. There are only minor differences between the amide carbonyl carbon CS tensors for Leu11 and Ala17 and between the nitrogen CS tensors for Leu15 and Ala22.Key words: orexin-B, solid-state NMR, REDOR, chemical shift tensors.
Spatial heterogeneity of lodgepole pine sapling densities following the 1988 fires in Yellowstone National Park, Wyoming, USA
Authors: Kashian Daniel M , Tinker Daniel B , Turner Monica G , Scarpace Frank L
Published: December 2004

Large disturbances create spatial heterogeneity in vegetation re-establishment, and documenting such variability is critical for understanding and predicting succession. We quantified the spatial heterogeneity of lodgepole pine sapling densities 10 years after the 1988 fires in Yellowstone National Park using color infrared orthophotographs. Densities were classified across the landscape at an accuracy of 70.9%, and landscape metrics were used to characterize their spatial variability. Densities ranged from 0 to > 500 000 saplings/ha, but >60% of the burned area was represented by densities <5000 stems/ha. The burned area consisted of small patches averaging 1.5 ha in area at a mean patch density of 68 patches/100 ha. Densities occurred in nearly equal proportions across the landscape (Shannon's evenness = 0.85) but were well dispersed (contagion index ≈ 20%), suggesting that densities varied in a complex, fine-grained mosaic across the landscape, with high-density patches occurring within a matrix of larger, lower density patches. High-density patches were similar in area to severe surface fires, suggesting that burn severity is an important explanatory variable for spatial variation in sapling density. Large, stand-replacing fires may result in heterogeneous forest landscapes rather than homogenous forests of uniform structure, which may have important consequences for postfire ecological processes.
The effect of local stand structure on growth and growth efficiency in heterogeneous stands of ponderosa pine and lodgepole pine in central Oregon
Authors: Mainwaring Douglas B , Maguire Douglas A
Published: December 2004

Basal area and height growth were analyzed for individual trees in uneven-aged ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex. Loud.) stands in central Oregon. Basal area growth was modeled as a function of other stand and tree variables to address three general objectives: (1) to compare the predictive ability of distance-dependent versus distance-independent stand density variables; (2) to determine the degree to which small trees negatively affect the growth of overstory trees; and (3) to test for differences in growth efficiency between species and between indices of spatial occupancy used to define efficiency (area potentially available, crown projection area, and a surrogate for total tree leaf area). Distance-dependent variables were found to improve growth predictions when added to models with only distance-independent variables, and small trees were found to have a quantifiably negative effect on the growth of larger trees. While volume growth efficiency declined with increasing levels of spatial occupancy for lodgepole pine, ponderosa pine volume growth efficiency was greatest at the highest levels of crown base sapwood area and crown projection area. The behavior in ponderosa pine resulted from the previously recognized correlation between tree height and total leaf area or crown size. The final statistical models distinguished between the positive effect of relative height and the negative effect of increasing tree size.
SURFACE ANALYSIS OF Bi2Sr2Can-1CunOy SUPERCONDUCTING WHISKERS USING X-RAY PHOTOELECTRON SPECTROSCOPY
Authors: TANAKA HIROMI , KISHIDA SATORU , YOSHIKAWA HIDEKI , KIMURA MASAHIRO , TANAKA AKIHIRO , FUKUSHIMA SEI , ANDOU KOUSHI
Published: December 2004

We investigated the chemical bond nature of the constituent elements in the surface of the as-grown Bi 2 Sr 2 Ca n-1 Cu n O y ( Bi -based) superconducting whiskers by a high-resolution X-ray photoelectron spectroscopy. From the results, we found that lots of the impurities, e.g., carbon, hydroxyl and so on were adsorbed or absorbed on the surface of the as-grown whiskers. Moreover, the valence of the Cu in CuO 2 plane which is important for superconductivity has changed from divalent to less than divalent, which leads to the existence of the insulating layers in the surface of the Bi -based superconducting whiskers.
INVESTIGATION OF ELECTRON TRANSPORT OF OPEN MOLECULAR STRUCTURES BASED ON FIRST PRINCIPLES THEORY
Authors: BAI PING , YANG SHUO-WANG , LI ER-PING , WU PING
Published: December 2004

We study the electron transport of thiolated benzene and borazine using ab initio method Transiesta through 3D atomic metal–molecule–metal structures. The calculation is based on well-established density functional theory (DFT) and nonequilibrium Green's functions (NEGF). DFT with norm conserving nonlocal pseudopotentials is used to define the atomic core and NEGF are used to calculate the charge distribution where the contributions of scattering sates and bound states to charge density are naturally accounted. The transmission functions and I–V characteristics are presented. Simulation results show that the conductance through benzene is about four times larger than through borazine. Negative differential resistance behavior is observed with borazine while saturation feature appears with benzene.
GIANT INCREASE OF THE EXCITON LIFETIME IN SEMIMAGNETIC SEMICONDUCTORS WITH DOUBLE QUANTUM WELLS IN MAGNETIC FIELD
Authors: Yu. GOLINEY I. , LEV S. B. , SUGAKOV V. I. , VERTSIMAKHA G. V.
Published: December 2004

Magnetic field dependence of the excitonic spectrum and the intensity of the optical transitions for excitons in the double quantum well heterostructures based on semimagnetic semiconductors of various compositions are studied. The calculations carried out for (Zn, Mn)Se -based double quantum well structures showed that in the weak magnetic fields, the lowest energy states are the single-well states (direct excitons) for which both the electron and the hole are predominantly localized in the same well. At some values of magnetic field, the crossing of the direct exciton with indirect exciton formed by an electron and a hole, situated predominantly in the different wells, occurs. In the magnetic field exceeding some critical value, the lowest energy level belongs to the indirect exciton. According to the estimates, the lifetime of the indirect exciton is by several orders of magnitude larger than that of a single-well exciton. The exciton lifetime depends significantly on the width and the material of the barrier between the wells.
ELECTRICAL PROPERTIES OF REACTIVELY-SPUTTERED HYDROGENATED CARBON NITRIDE FILMS
Authors: WEI J.
Published: December 2004

Hydrogenated carbon nitride films have been synthesized on Si (100) by DC reactive sputtering with RF bias. These films are characterized by transmission electron microscopy and atomic force microscopy. Hydrogenated carbon nitride films have low surface roughness. At low hydrogen fraction, the films include small crystallites. High hydrogen fraction promotes the films to be amorphous. The resistivities of the films are measured, which range from 6.35×105 to 1.16×108 Ω· cm . The measured resistivity results indicate that the hydrogenated carbon nitride films have semiconductive properties. The resistivity largely depends on the bonding configurations. Effects of H2 fraction, target current and substrate bias are investigated. All these deposition parameters have influence on the resistivities. High C—H, N—H and C—NH bond fractions result in high resistivity.
EVOLUTION AND ORDERING OF MULTILAYER Ge QUANTUM DOTS ON Si(001)
Authors: JEYANTHINATH M. , XU M. J. , WANG X.-S.
Published: December 2004

Evolution and ordering of multilayer Ge islands (up to 14 layers) on Si (001), prepared by physical vapor deposition at about 550°C; were studied using Scanning Tunneling Microscope (STM). In the growth process, it was observed that long huts split during the deposition of Si buffer layer. It can be explained as a consequence of strain due to lattice mismatch and intermixing of Si and Ge to form solid solution. Such a mechanism of splitting could lead the dots to order and uniformity in the subsequent layers. Apart from splitting of huts, the surface corrugation of Si spacer layer influences the nucleation of Ge islands in the next layer.
THE APPLICATION OF SELF-ASSEMBLY MONOLAYER TECHNIQUE INTO FABRICATING MULTILAYER NANOFILM
Authors: PENG Z. , KONG L.-X.
Published: December 2004

Self-Assembly Monolayer (SAM) technique, as a novel and developing technique for fabricating layer-by-layer nanofilm on substrates of various sizes, shapes and materials, has received more and more attention in the areas of light-emitting devices, nonlinear optical materials, conductive films, permselective gas membranes, sensors, modification of electrodes, resistance and printing technique. In comparison with other traditional methods, SAM technique has many significant advantages, including simple process, universality, formation with densely packed, well defined, highly ordered surfaces. This paper will give a review on the recent development in SAM technique.
Hepatic triglyceride contents are genetically determined in mice: results of a strain survey
Authors: Lin Xiaobo , Yue Pin , Chen Zhouji , Schonfeld Gustav
Published: December 2004

To assess whether genetic factor(s) determine liver triglyceride (TG) levels, a 10-mouse strain survey of liver TG contents was performed. Hepatic TG contents were highest in BALB/cByJ, medium in C57BL/6J, and lowest in SWR/J in both genders. Ninety and seventy-six percent of variance in hepatic TG in males and females, respectively, was due to strain (genetic) effects. To understand the physiological/biochemical basis for differences in hepatic TG among the three strains, studies were performed in males of the BALB/cByJ, C57BL/6J, and SWR/J strains. In vivo hepatic fatty acid (FA) synthesis rates and hepatic TG secretion rates ranked BALB/cByJ ≈ C57BL/6J > SWR/J. Hepatic 1-14C-labeled palmitate oxidation rates and plasma β-hydroxybutyrate concentrations ranked in reverse order: SWR/J > BALB/cByJ ≈ C57BL/6J. After 14 h of fasting, plasma-free FA and hepatic TG contents rose most in BALB/cByJ and least in SWR/J. β-Hydroxybutyrate concentrations rose least in BALB/cByJ and most in SWR/J. Adaptation to fasting was most effective in SWR/J and least in BALB/cByJ, perhaps because BALB/cByJ are known to be deficient in SCAD, a short-chain FA oxidizing enzyme. To assess the role of insulin action, glucose tolerance test (GTT) was performed. GTT-glucose levels ranked C57BL/6J > BALB/cByJ ≈ SWR/J. Thus strain-dependent (genetic) factors play a major role in setting hepatic TG levels in mice. Processes such as FA production and hepatic export in VLDL on the one hand and FA oxidation on the other, explain some of the strain-related differences in hepatic TG contents. Additional factor(s) in the development of fatty liver in BALB/cByJ remain to be demonstrated.
Middle cerebral artery flow velocity and pulse pressure during dynamic exercise in humans
Authors: Ogoh Shigehiko , Fadel Paul J. , Zhang Rong , Selmer Christian , Jans Øivind , Secher Niels H. , Raven Peter B.
Published: December 2004

Exercise challenges cerebral autoregulation (CA) by a large increase in pulse pressure (PP) that may make systolic pressure exceed what is normally considered the upper range of CA. This study examined the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) and systolic ( Vs), diastolic ( Vd). and mean ( Vm) middle cerebral artery (MCA) blood flow velocity during mild, moderate, and heavy cycling exercise. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated using transfer function analysis. PP increased by 37% and 57% during moderate and heavy exercise, respectively ( P < 0.05), and the pulsatility of MCA V increased markedly. Thus exercise increased MCA Vmand Vs( P < 0.05) but tended to decrease MCA Vd( P = 0.06). However, the normalized low-frequency transfer function gain between MAP and MCA Vmand between SBP and MCA Vsremained unchanged from rest to exercise, whereas that between DBP and MCA Vdincreased from rest to heavy exercise ( P < 0.05). These findings suggest that during exercise, CA is challenged by a rapid decrease rather than by a rapid increase in blood pressure. However, dynamic CA remains able to modulate blood flow around the exercise-induced increase in MCA Vm, even during high-intensity exercise.
Does Increased Predicted Warm-Season Rainfall Indicate Enhanced Likelihood of Rain Occurrence?
Authors: Gallus William A. , Segal Moti
Published: December 2004

The likelihood of simulated rainfall above a specified threshold being observed is evaluated as a function of the amounts predicted by two mesoscale models. Evaluations are performed for 20 warm-season mesoscale convective system events over the upper Midwest of the United States. Simulations were performed using 10-km versions of the National Centers for Environmental Prediction Eta Model and the Weather Research and Forecasting (WRF) model, with two different convective parameterizations tested in both models. It was found that, despite large differences in the biases of these different models and configurations, a robust relationship was present whereby a substantial increase in the likelihood of observed rainfall exceeding a specified threshold occurred in areas where the model runs forecast higher rainfall amounts. Rainfall was found to be less likely to occur in those areas where the models indicated no rainfall than it was elsewhere in the domain; it was more likely to occur in those regions where rainfall was predicted, especially where the predicted rainfall amounts were largest. The probability of rainfall relative-operating-characteristic and relative-operating-level curves showed that probabilistic forecasts determined from quantitative precipitation forecast values had skill comparable to the skill obtained using more traditional methods in which probabilities are based on the fraction of ensemble members experiencing rainfall. When the entire sample of cases was broken into training and test sets, the probability forecasts of the test sets evidenced good reliability. The relationship noted should provide some additional guidelines to operational forecasters. The results imply that the tested models are better able to indicate the regions where atmospheric processes are most favorable for convective rainfall (where the models generate enhanced amounts) than they are able to predict accurately the rainfall amounts that will be observed.
The ROC Curve and the Area under It as Performance Measures
Authors: Marzban Caren
Published: December 2004

The receiver operating characteristic (ROC) curve is a two-dimensional measure of classification performance. The area under the ROC curve (AUC) is a scalar measure gauging one facet of performance. In this short article, five idealized models are utilized to relate the shape of the ROC curve, and the area under it, to features of the underlying distribution of forecasts. This allows for an interpretation of the former in terms of the latter. The analysis is pedagogical in that many of the findings are already known in more general (and more realistic) settings; however, the simplicity of the models considered here allows for a clear exposition of the relation. For example, although in general there are many reasons for an asymmetric ROC curve, the models considered here clearly illustrate that an asymmetry in the ROC curve can be attributed to unequal widths of the distributions. Furthermore, it is shown that AUC discriminates well between “good” and “bad” models, but not between good models.
Strategies for Identifying Critical Seismic Response Combinations
Authors: Menun Charles
Published: December 2004

The effects of multiple seismic responses acting simultaneously within a structural element must often be considered when checking the capacity of the element or determining its required dimensions or material properties. In particular, an element is viewed as being adequately designed if all combinations of the responses as they evolve during an earthquake remain in the safe region of the response space defined by the relevant capacity surface of the element. In this paper, algorithms are developed to facilitate the comparison of available response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of either assessing the adequacy of an existing design of a structural element or determining the required value of a design parameter. Comprehensive examples are used to demonstrate the implementation, interpretation, and utility of the proposed algorithms.
Criticism of Current Seismic Design and Construction Practice in Venezuela: A Bleak Perspective
Authors: Searer Gary R. , Fierro Eduardo A.
Published: December 2004

During a recent visit to Caracas, Venezuela, the authors discovered that while Venezuela has adopted a building code with modern seismic provisions (Norma Covenin 1756-98) and does in fact enforce a majority of these provisions, significant conceptual errors in the design of the lateral force-resisting systems of new buildings are recurring on a near-universal level, often as a result of ignoring the potential adverse effects of nonstructural elements on the structural system. In the event of a large earthquake, this design philosophy will have substantial economic and life-safety repercussions unless the typical design philosophy of Venezuelan engineers and architects changes. It is hoped that this paper will serve as a call to action for engineers of all countries to recognize the potential adverse effects of nonstructural elements on the behavior of the lateral force-resisting system.
Site-Dependent Spectra Derived from Ground Motion Records in Turkey
Authors: Kalkan Erol , Gülkan Polat
Published: December 2004

The current spectral shapes in the Turkish Seismic Code ( TSC) are based on broadly described geological conditions, ignoring fault distance or magnitude dependencies on spectral ordinates. To address this deficiency, a data set created from a suite of 112 strong ground motion records from 57 earthquakes that occurred between 1976 and 2003 has been used to develop horizontal attenuation relationships for Turkey. This way it is possible to construct hazard-consistent design spectra for any national seismic region. The results are compared with the site-dependent spectral shapes of the Uniform Building Code ( UBC) and the current TSC. It is shown that corner periods are consistent with those of UBC. TSC yields wider constant spectral acceleration plateau. Design spectra in both of these documents are conservative if the ground motion library that we used in deriving the spectral shapes is taken as representative. The results of this study enable site-distance–magnitude-specific design spectra suitable as a tool both for deterministic (scenario earthquakes) and probabilistic seismic hazard assessments.
Experimental Investigation of Reduced Beam Section Moment Connections without Continuity Plates
Authors: Pantelides Chris P. , Okahashi Yasuteru , Reaveley Lawrence D.
Published: December 2004

The AISC 2002 Seismic Provisions for Structural Steel Buildings recommend that usage and sizing of beam flange continuity plates across the column web shall be based on tests. The Recommended Seismic Design Criteria for New Steel Moment-Frame Buildings ( FEMA-350) state that unless project-specific testing is performed to demonstrate that continuity plates are not required, moment-resisting connections should be provided with continuity plates when the thickness of the column flange is below a minimum value. One of the preferred moment connections for seismic-resistant steel frames is the reduced beam section (RBS) moment connection, which has performed well under cyclic loads in laboratory testing. To demonstrate the effectiveness of the RBS moment connection without continuity plates in the panel zone, a series of four full-scale tests of exterior beam-column connections was carried out. All materials were A572 Grade 50 steel; the beams were W30×132, two of the assemblies used W14×283 columns, and the other two used W18×211 columns. The beams were welded to the columns using complete joint-penetration welds. All four tests demonstrated that the RBS connections without continuity plates developed a total interstory drift angle greater than 0.04 radians and met the requirements for special moment frames.
Prenatal Maternal Anxiety and Depression Predict Negative Behavioral Reactivity in Infancy
Authors: Davis Elysia Poggi , Snidman Nancy , Wadhwa Pathik D. , Glynn Laura M. , Schetter Chris Dunkel , Sandman Curt A.
Published: December 2004

The effects of maternal antenatal and postnatal anxiety and depression on infant negative behavioral reactivity were examined in a sample of 22 mother‐infant pairs. Maternal anxiety and depression were assessed by standardized measures during the third trimester of pregnancy and postpartum. Infant negative behavioral responses to novelty were assessed using a previously validated measure at 4 months of age. Maternal anxiety and depression during the prenatal, but not the postnatal period, were related to infant negative behavioral reactivity to novelty. These data illustrate that prenatal maternal psychological state can exert persisting influences on human infant behavior.
Sex Differences in Infants' Ability to Represent Complex Event Sequences
Authors: Schweinle Amy , Wilcox Teresa
Published: December 2004

Prior research suggests that when very simple event sequences are used, 4.5‐month‐olds demonstrate the ability to individuate objects based on the continuity or disruption of their speed of motion (Wilcox & Schweinle, 2003). However, infants demonstrate their ability to individuate objects in an event‐monitoring task (i.e., infants must keep track of an ongoing event) at a younger age than in an event‐mapping task (i.e., infants must compare information from 2 different events). The research presented here built on these findings by examining infants' capacity to succeed on an event‐mapping task with a more complex event sequence to determine if the complexity of the event interferes with their ability to form summary representations of the event, and, in short, individuate the objects. Three experiments were conducted with infants 4.5 to 9.5 months of age. The results indicated that (a) increasing the complexity of the objects' trajectories adversely affected infants' performance on the task, and (b) boys were more likely to succeed than girls. These findings shed light on how representational capacities change during the first year of life and are discussed in terms of information processing and representational capabilities as well as neuro‐anatomical development.
14‐Month‐Old Infants Form Novel Word—Spatial Relation Associations
Authors: Casasola Marianella , Wilbourn Makeba Parramore
Published: December 2004

This study explored 14‐month‐old infants' ability to form novel word‐spatial relation associations. During habituation, infants heard 1 novel word (e.g., teek) while viewing dynamic containment events (i.e., Big Bird placed in a box) and, on other habituation trials, a second novel word (e.g., blick) while viewing dynamic support events (i.e., Big Bird placed on the box). Each novel word was presented in a sentence (e.g., “She's putting Big Bird teek the box”). During the test, infants discriminated an event that maintained the habituation word‐relation pairing from one that presented a switch in this pairing. The results indicate that 14‐month‐olds can learn to form word‐relation associations quickly, requiring only a few minutes of experience with each word‐relation pairing.
An Event—Emotion or Event—Expression Hypothesis? A Comment on the Commentaries on Bennett, Bendersky, and Lewis (2002)
Authors: Camras Linda A.
Published: December 2004

The hypothesis investigated by Bennett, Bendersky, and Lewis (2002) has 2 components. The first concerns relations between events and emotions, and the second concerns relations between emotions and facial expressions. These components should be conceptually distinguished, independently investigated, and separately evaluated.
Developmental Diethylstilbestrol Exposure Alters Genetic Pathways of Uterine Cytodifferentiation
Authors: Huang Wei-Wei , Yin Yan , Bi Qun , Chiang Tung-Chin , Garner Neysa , Vuoristo Jussi , McLachlan John A. , Ma Liang
Published: December 2004

The formation of a simple columnar epithelium in the uterus is essential for implantation. Perturbation of this developmental process by exogenous estrogen, such as diethylstilbestrol (DES), results in uterine metaplasia that contributes to infertility. The cellular and molecular mechanism underlying this transformation event is not well understood. Here we use a combination of global gene expression analysis and a knockout mouse model to delineate genetic pathways affected by DES. Global gene expression profiling experiment revealed that neonatal DES treatment alters uterine cell fate, particularly in the luminal epithelium by inducing abnormal differentiation, characterized by the induction of stratified epithelial markers including members of the small proline-rich protein family and epidermal keratins. We show that Msx2, a homeodomain transcription factor, functions downstream of DES and is required for the proper expression of several genes in the uterine epithelium including Wnt7a, PLAP, and K2.16. Finally, Msx2−/− uteri were found to exhibit abnormal water trafficking upon DES exposure, demonstrating the importance of Msx2 in tissue responsiveness to estrogen exposure. Together, these results indicate that developmental exposure to DES can perturb normal uterine development by affecting genetic pathways governing uterine differentiation.
11β-Hydroxysteroid Dehydrogenase Expression and Glucocorticoid Synthesis Are Directed by a Molecular Switch during Osteoblast Differentiation
Authors: Eijken M. , Hewison M. , Cooper M. S. , de Jong F. H. , Chiba H. , Stewart P. M. , Uitterlinden A. G. , Pols H. A. P. , van Leeuwen J. P. T. M.
Published: December 2004

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) plays an important role in the prereceptor regulation of corticosteroids by locally converting cortisone into active cortisol. To investigate the impact of this mechanism on osteoblast development, we have characterized 11β-HSD1 activity and regulation in a differentiating human osteoblast cell line (SV-HFO). Continuous treatment with the synthetic glucocorticoid dexamethasone induces differentiation of SV-HFO cells during 21 d of culture. Using this cell system, we showed an inverse relationship between 11β-HSD1 activity and osteoblast differentiation. 11β-HSD1 mRNA expression and activity were low and constant in differentiating osteoblasts. However, in the absence of differentiation (no dexamethasone), 11β-HSD1 mRNA and activity increased strongly from d 12 of culture onward, with a peak around d 19. Promoter reporter studies provided evidence that specific regions of the 11β-HSD1 gene are involved in this differentiation controlled regulation of the enzyme. Functional implication of these changes in 11β-HSD1 is shown by the induction of osteoblast differentiation in the presence of cortisone. The current study demonstrates the presence of an intrinsic differentiation-driven molecular switch that controls expression and activity of 11β-HSD1 and thereby cortisol production by human osteoblasts. This efficient mechanism by which osteoblasts generate cortisol in an autocrine fashion to ensure proper differentiation will help to understand the complex effects of cortisol on bone metabolism.
Racemic-to-Chiral Transformation in Cobaloxime Complex Crystals Only by Photoirradiation
Authors: Nemoto Takashi , Ohashi Yuji
Published: December 2004

The cobaloxime complex crystal with the racemic-1-cyanoethyl group and piperidine as axial ligands, which has a chiral space group of P212121, changed its cell dimensions with retention of the single crystal form on exposure to visible light. The chloroform solution of the crystals after irradiation showed the optical rotation ([α]D = 30°). This indicates the racemic-to-chiral transformation occurred in the crystal only by photoirradiation. The crystal before irradiation, analyzed by X-rays, has two complexes with R- and S-1-cyanoethyl groups in the asymmetric unit. After irradiation, one of the complexes with the S group, which has a larger reaction cavity than the R group, was partly inverted to create a disordered structure. The R : S ratio in the crystal changed from 50 : 50 to 70 : 30. The final ratio of 70 : 30 is well explained by the symmetric shape of the reaction cavity after the change. For the cobaloxime complex crystal with the racemic-1-cyanoethyl group and pyrrolidine as axial ligands, a similar transformation was observed. The racemic crystal with the space group P1 has four complexes in a unit cell, two of which have a R-1-cyanoethyl group while the other two complexes have a S-1-cyanoethyl group. The complexes with the S group, which have larger cavities than those with the R group, were partly inverted to create the opposite configuration. This caused optical enrichment in the crystal. Such a racemic-to-chiral transformation will be observed not rarely but commonly if the racemic crystals with chiral space groups will be examined cautiously.
Mechanism of the Photosensitized Chemiluminescence of Luminol
Authors: Yasuta Norihiko , Takahashi Sinjiro , Takenaka Nobuo , Takemura Takeshi
Published: December 2004

The photosensitized chemiluminescence (CL) of luminol in basic aqueous solution has been investigated by pulsed laser irradiation and by steady state light irradiation in order to clarify the CL in terms of Type-I (electron transfer) and Type-II (singlet oxygen) mechanisms. Short-lived (μs) and long-lived (ms) CL were observed at 420 nm upon pulsed laser irradiation near 530 nm of the luminol/sensitizer reaction mixture. The kinetics of the CL decay is explained by four rate constants,

I(t) = Aex{exp(−k2t) − exp(−k1t)} + Bex{exp(−k4t) − exp(−k3t)}.

These results, in addition to the results under steady state conditions, suggest that the long-lived CL dominates the photosensitized CL, which is caused by electron transfer to the triplet state of the sensitizers from luminol (Type-I). On the other hand, short-lived CL is due to a reaction between singlet oxygen and luminol (Type-II), the efficiency of which is smaller by two orders of magnitude compared to that of the Type-I mechanism.
A Possibility of Macroscopically Asymmetric Diffusion on Stepped Surfaces
Authors: Seto Takatoshi
Published: December 2004

We studied the macroscopic-scale surface diffusion of adsorbates under strong adsorbate–adsorbate lateral interactions (A–A potential) on a surface with periodically repeated asymmetric potential curves, such as a well-ordered stepped surface. By considering a potential curve made of adsorbate–substrate (A–S) and A–A potentials in a random-walk model, we found an asymmetry in a migration probability of an adsorbate in opposite directions. On this basis, we derived and predicted the existence of macroscopically asymmetric diffusion. A Monte-Carlo calculation of the random walk of adsorbates with a certain strong repulsive A–A potential on fcc (112) or bcc (013) caused the adsorbates to diffuse more in a direction of jumping the minimum A–S activation energy, and a difference in flux of the adsorbates in opposite directions greatly depended on the concentration.
Radiolytic and Thermal Dehalogenation of CFC-113 Adsorbed on Molecular Sieve 13X
Authors: Yamamoto Yukio , Tagawa Seiichi
Published: December 2004

The reductive dehalogenation of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) has been radiolytically and thermally initiated on molecular sieve 13X. The molecular sieve adsorbing CFC-113 was irradiated with γ-rays or heated, and was then soaked in water. The Cl− and F− concentrations and the pH of the supernatant solutions were measured to follow the dehalogenation reaction. These values for samples irradiated at a dose rate of 7.8 kGy h−1 and heated at 150 °C were almost the same when the irradiation time was twenty-times longer than the heating time. The F− concentration once increased and then decreased with the reaction time, whereas the Cl− concentration increased continuously. The F−, once produced, may be consumed with the denatured molecular sieve. When the molecular sieve adsorbing 2-propanol together with CFC-113 was irradiated, the dechlorination proceeded by a chain reaction, but the defluorination was inhibited. On the other hand, when heated in the presence of 2-propanol, both the dechlorination and the defluorination were largely suppressed. The pH of the supernatant solutions decreased from an alkaline value to a neutral or acidic one along with dehalogenation. Radiolysis of CFC-113 on activated charcoal was also examined, but the dehalogenation rates were much slower than those on the molecular sieve.
Photoemission Cross Sections for Fragments and Molecular Ions Produced by Collisions of He(2 3S) Atoms with SiCl4 and GeCl4
Authors: Tokue Ikuo , Tanaka Hiroyuki , Yamasaki Katsuyoshi
Published: December 2004

Photoemissions from excited fragments and molecular ions produced by collisions of He(2 3S) with SiCl4 and GeCl4 have been studied at the relative collision energy of 120—210 meV. Total emission cross sections in the 200—760 nm range for SiCl4 and GeCl4 are evaluated to be 4.5 ± 0.8 and 2.2 ± 0.4, respectively, in 10−20 m2 units. Emission cross sections for SiCl4+(), GeCl4+(), and Ge I atomic lines slightly decrease with increases in the collision energy. This originates from the fact that the effective potentials of He(2 3S) with SiCl4 and GeCl4 are slightly attractive. The branching ratio of Ge I states observed from GeCl4 is consistent with a simple dissociation model assuming equipartition of the available energy. These results are compatible with the harpoon mechanism as an initial step for formation of Ge I from GeCl4. The emission cross section for the SiCl(B′–X) band increases with the collision energy. This indicates that the effective potential between He(2 3S) and SiCl4 is repulsive, and that the SiCl(B′) state seems to be produced directly from SiCl4 by an excitation transfer mechanism via superexcited states.
Organotin Esters of N-Phthaloylamino Acids: Synthesis, Spectroscopic Characterization, and Biological Activities
Authors: Ashfaq Muhammad , Majeed Abdul , Rauf Abdul , Khanzada Abdul Wahab Khan , Shah Wali Ullah , Ansari Muhammad Iqbal
Published: December 2004

The synthesis, physical nature and spectroscopic characterization, i.e. CHN analyses as well as the IR, 1H-, 13C-, 119Sn NMR and 119mSn Mössbauer spectrometries, of a series of new organotin complexes of N-phthaloylamino acids are described. The monomeric diorganotin complexes possess a trans octahedral geometry. The dimeric tetraorganotin complexes have a penta-coordinate environment. The triphenyltin with N-phthaloylamino acids are assigned a polymeric trigonal bipyramidal geometry in the solid form and a tetrahedral structure in an inert solvent, while tricyclohexyltin with N-phthaloylamino acids complexes possess a tetrahedral geometry. ED50 and biological activities tests were also carried out, which indicated powerful biocidal effects.
Structure and Organic Gas-Adsorption Properties of Some Polyamine Intercalated α-Zirconium Phosphates
Authors: Danjo Mayumi , Hayashi Aki , Nakayama Hirokazu , Kimira Yumi , Shimizu Tomoko , Mizuguchi Yukari , Yagita Yukari , Tsuhako Mitsutomo , Nariai Hiroyuki , Motooka Itaru
Published: December 2004

The intercalation of polyamine into α-zirconium phosphate (α-ZrP) was examined at room temperature and 80 °C. In triethylenetetramine (3E4A), tetraethylenepentamine (4E5A), and pentaethylenehexamine (5E6A) the temperature of the reactions influenced the rate of intercalation, but did not effect the structure of the intercalation compound. On the other hand, the ratios of the constituent phases in the N,N′-bis(3-aminopropyl)-1,3-propanediamine (3P4A) intercalated solid were greatly influenced by the reaction temperature, and two phases with the different interlayer distances could be formed by controlling it. In the phase with an interlayer distance of d = 20 Å, obtained predominantly at 80 °C, 3P4A was present as a monolayer of extended molecules in the interlayer region, in which the longitudinal axis of 3P4A was inclined at ca. 60° to the α-ZrP layers. In the phase with d = 17 Å, obtained at room temperature, 3P4A existed as a bent form. These polyamine intercalated solids drastically adsorbed acetic acid, formaldehyde, acetaldehyde, and cinnamaldehyde.