bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, X‐ray Structures, Spectroscopic and Thermal Characterization of Two New Organic Ammonium Tetrathiotungstates
Authors: Srinivasan Bikshandarkoil R. , Dhuri Sunder N. , Poisot Martha , Näther Christian , Bensch Wolfgang
Published: April 2005

Two new tetrathiotungstates (pipH2)[WS4] (1) and (trenH2)[WS4] · H2O (2) (pip = piperazine and tren = tris(2‐aminoethyl)amine) were synthesized and characterized by elemental analysis, infrared, Raman, UV‐Visible and 1H NMR spectroscopy, single crystal X‐ray crystallography, and thermoanalysis. In 1 and 2 the amines pip and tren are diprotonated and they are linked to the [WS4]2− tetrahedra via weak N‐H···S (1, 2) and N‐H···O (2) hydrogen bonds. In 2 the H atoms of the H2O molecule have also contacts to S atoms. The strength and number of the S···H interactions affect the W‐S bond lengths and a relatively long W‐S bond of 2.2147(7) Å is observed in 1 while the longest W‐S bond in 2 is 2.1997(6) Å. The different degree of distortion of the [WS4]2− anions is reflected in the IR and Raman spectra. The compounds decompose upon heating in an inert atmosphere to form amorphous WS2.1C1.2N0.3 and WS2.1C3N0.8 respectively, and the C and N content of the decomposition products is determined by the C and N content of the amines. In contrast to other tetrathiotungstates, the thermal reaction of both compounds do not proceed via amorphous WS3 as an intermediate phase. Compound 2 can be reversibly de‐ and re‐hydrated, and the process of re‐hydration proceeds presumably via dissolution‐re‐crystallization mechanism.
The Controlled Oxidative Coupling of Ge94− Zintl Anions to a Linear Trimer [Ge9=Ge9=Ge9]6−
Authors: Yong Li , Hoffmann Stephan D. , Fässler Thomas F.
Published: April 2005

The compound [K(18‐crown‐6)]6[Ge9=Ge9=Ge9]·3en·tol (1) featuring a [Ge9=Ge9=Ge9]6− cluster anion was synthesized from K4Ge9. The neighboured nine‐atom clusters are connected by two covalent Ge‐Ge exo‐cluster bonds with the Ge‐Ge distances ranging from 2.581 to 2.640Å. The X‐ray single crystal structure analysis shows that, in respect to bond connection and packing style, compound 1 is quite different from the previously reported compound [Rb(2.2.2‐crypt)]6[Ge9=Ge9=Ge9]·3en (2).
From Amorphous Aggregates to Crystallites: Modelling Studies of Crystal Growth in Vacuum
Authors: Kawska A. , Brickmann J. , Hochrein O. , Zahn Dirk
Published: April 2005

The growth of NaCl and CaF2 aggregates is studied with the framework of an atomistic simulation approach. Our method combines a Monte‐Carlo type scheme for the identification of ion adsorption sites and structural optimization of the ion cluster after individual growth steps. This allows investigating putative conformers of ion aggregates as a function of size. The structure of clusters counting only a small number of ions was found to be quite amorphous. During the early stage of aggregate growth, the addition of further ions leads to considerable structural changes. Once the clusters exceed a critical size, a disorder→order transition is observed, leading to large domains exhibiting motifs of the crystalline structure. Such crystalline regions were found to be stable and hence change only marginally during further aggregate growth.
In Situ High Temperature Neutron Diffraction Study of Sr/Mg‐doped Lanthanum Gallate Superionic Conductors under Microwave Irradiation
Authors: Günter M. M. , Korte C. , Brunauer G. , Boysen Hans , Lerch Martin , Suard E.
Published: April 2005

First in situ high temperature neutron scattering experiments under microwave irradiation have been carried out on a superionic conductor, doped LaGaO3. A definite non‐thermal microwave effect on the resulting crystallographic structures was discovered mainly derived from oppositechanges of the lattice constants and the atomic displacement parameters. These effects are related to changes in the phonon density of states (DOS) due to coupling of the microwave field via (anharmonic) multi phonon processes, limited phonon life times and local modes arising from the defects. The problem of defining a temperature in a microwave field due to the non‐equilibrium DOS is discussed.
Cs3OsH9 ‐ Synthese, Struktur und magnetische Eigenschaften
Authors: Auffermann G. , Bronger Welf , Müller P. , Roth G. , Schilder H. , Sommer T.
Published: April 2005

Cs3OsH9 ‐ Synthesis, Structure, and Magnetic Properties

Cs3OsD9 was synthesized by the reaction of cesium deuteride with osmium powder at 870 K and a deuterium pressure above 1500 bar.

Elastic neutron diffraction experiments on a powder sample at room temperature led to an atomic arrangement nearly describable in a cubic unit cell (Pm3m; a = 6.128(2) Å, Z = 1). According to the formula Cs3D[OsD8] the structure corresponds to that of the perovskite type. The coordination polyhedron of the deuterium atoms surrounding each osmium atom can be described crystallographically as a statistical occupation of two 24‐fold positions with deuterium. A detailed investigation on the gaussian profiles of the neutron diffraction pattern leads to the result that the compound crystallizes in a tetragonal unit cell with a = 8.602(1) Å, c = 12.250(1) Å and Z = 4. Below a phase transition at 110 K an orthorhombic unit cell was found with a = 8.6983(4) Å, b = 8.6046(4) Å, c = 11.9437(6) Å and Z = 4. A provisional structure model is presented.

Magnetic susceptibility measurements in the temperature range between 1.8 and 400 K reveal a weak paramagnetism. Quantum mechanical calculations confirm the experimental result and show in detail that spin momentum and orbital momentum cancel each other nearly complete with regard to the ground state.
Structural and Electronic Properties of Bulk Gibbsite and Gibbsite Surfaces
Authors: Frenzel Johannes , Oliveira Augusto F. , Duarte Helio A. , Heine Thomas , Seifert Gotthard
Published: April 2005

Structure and electronic structure of gibbsite and gibbsite surfaces are studied using gradient‐corrected density functional theory and a density‐functional based tight‐binding (DFTB) scheme. The electronic density‐of‐states (DOS) is insignificantly changed when comparing bulk and single‐layer (001) surfaces, but changes for other surfaces, as pentacoordinated Al sites appear. Model structures of other chemically relevant surfaces are proposed, including a stripe and an Al6(OH)18 cluster model for the (100) face, which turns out to be equivalent to the (011) face if only covalently bound blocks are considered. In all cases quantitative agreement of GGA‐DFT and DFTB for structures and occupied electronic states is observed.
New Computational Methods for Solving Problems of the Astronomical Vessel Position
Authors: Hsu Tien-Pen , Chen Chih-Li , Chang Jiang-Ren
Published: April 2005

In this paper, a simplified and direct computation method formulated by the fixed coordinate system and relative meridian concept in conjunction with vector algebra is developed to deal with the classical problems of celestial navigation. It is found that the proposed approach, the Simultaneous Equal-altitude Equation Method (SEEM), can directly calculate the Astronomical Vessel Position (AVP) without an additional graphical procedure. The SEEM is not only simpler than the matrix method but is also more straightforward than the Spherical Triangle Method (STM). Due to tedious computation procedures existing in the commonly used methods for determining the AVP, a set of optimal computation procedures for the STM is also suggested. In addition, aimed at drawbacks of the intercept method, an improved approach with a new computation procedure is also presented to plot the celestial line of position without the intercept. The improved approach with iteration scheme is used to solve the AVP and validate the SEEM successfully. Methods of solving AVP problems are also discussed in detail. Finally, a benchmark example is included to demonstrate these proposed methods.
Internet AIS
Authors: Filjar Renato , Desic Sasa , Pokrajac Danijela , Cubic Ivica
Published: April 2005

Automatic Identification System (AIS) has recently become the leading issue in maritime navigation and traffic management worldwide. The present AIS solution, based on a VHF data communications scheme, provides AIS functionalities for SOLAS (AIS Class A) vessels only in a limited environment defined by radio propagation properties. Here we present a novel approach in AIS development based on current mobile communication technologies. It utilises existing mobile communications equipment that the majority of targetted end-users own and are familiar with. A novel AIS concept aims to offer a transition of AIS data traffic to mobile Internet. An innovative AIS architecture supports AIS data processing, storing and transferring to authorised parties. This enhances not only the operational area, but also provides the global AIS with data transfer security and an improved aids-for-navigation service, with all legally traceable vessels (both AIS Class A and AIS Class B) included in the system. In order to provide the development framework for Internet AIS, a set of essential four use-cases, a communication protocol and the first Internet AIS prototype have been recently developed and are briefly introduced in this article.
The views of parents concerning the planning of services for rehabilitation of families of children with congenital cardiac disease
Authors: Kendall Lynne , Sloper Patricia , Lewin Robert J. P. , Parsons Jonathan M.
Published: April 2005

Background and purpose:Although much previous research has focused on the medical aspects of congenital cardiac disease, there is a growing body of research which suggests that families may need help and support with the wider issues associated with the medical condition. We have previously ascertained from young people with congenital cardiac disease their views on this subject. The purpose of this study was to obtain the views of their parents about the need for, and shape of, services for rehabilitation.Methods:This was a qualitative study using semi-structured interviews. We interviewed 17 parents in their own home. Interviews were tape-recorded and transcribed.Results:Parents would welcome more help and support from health professionals to enable them to manage more effectively the condition with their children. Particular areas of concern relate to the information they receive about the condition; communication between themselves and health professionals; establishing safe levels of activity; and managing the condition at school.Conclusions:This is a small study of the experiences and views of parents, which provides some important information on ways in which health professionals could address the current lack of services for rehabilitation.
Effects of therapeutic beta blockade on myocardial function and cardiac remodelling in congenital cardiac disease
Authors: Buchhorn Reiner , Hulpke-Wette Martin , Ruschewski Wolfgang , Ross Robert D , Fielitz Jens , Pregla Reinhard , Hetzer Roland , Regitz-Zagrosek Vera
Published: April 2005

Background:Cardiac remodelling is now recognised as an important aspect of cardiovascular disease progression and is, therefore, emerging as a therapeutic target in cardiac failure due to different etiologies. Little is known about the influence of different therapies for cardiac failure on the remodelling seen in infants with congenital cardiac disease.Methods:During follow-up of a prospective and randomized trial, we investigated therapeutic effects on neurohormonal activation, ventricular function, and myocardial gene expression. We compared the data from 8 infants with severe congestive heart failure due to left-to-right shunts, who received digoxin and diuretics alone, to 9 infants who received additional treatment with propranolol.Results:In these infants, β-adrenergic blockade significantly reduced highly elevated levels of renin, from 284 ± 319 μU/ml compared to 1061 ± 769 μU/ml. Systolic ventricular function was normal in both groups, but diastolic ventricular function was improved in those receiving propranolol, indicated by significantly lower left atrial pressures, lower end-diastolic pressures, and less pronounced ventricular hypertrophy, the latter estimated by lower ratios of myocardial wall to ventricular cavity areas on average of 42%. Further hemodynamic parameters showed no significant differences between the groups, except for the lower heart rate in infants treated with propranolol. In those treated with digoxin and diuretics, there was a significant downregulation of β2-receptor and angiotensin-2 receptor genes, and up-regulation of endothelin A receptor and connective tissue growth factor genes, that were partially prevented by additional treatment with propranolol.Conclusions:β-blockade is a new therapeutic approach for congestive heart failure in infants with congenital cardiac disease, producing with significant benefits on neurohormonal activation, diastolic ventricular function, and cardiac remodelling.
The clinical pathway for fast track recovery of school activities in children after minimally invasive cardiac surgery
Authors: Ono Masamichi , Fukushima Norihide , Ohtake Shigeaki , Ichikawa Hajime , Kagisaki Koji , Matsushita Tohru , Matsuda Hikaru
Published: April 2005

Background:Minimally invasive cardiac surgery is now becoming standard in the correction of simple congenital cardiac malformations. We introduced a clinical pathway for fast track recovery of school activities in children after minimally invasive cardiac surgery, and assessed the function of the pathway in children with atrial or ventricular septal defects, comparing minimally invasive surgery to repair through a conventional full sternotomy.Methods:We studied 15 children of school age who underwent repair of an atrial or ventricular septal defect through a lower midline sternotomy, and 10 children undergoing repair through a full sternotomy. The clinical pathway was for extubation to take place in the operating room, echocardiographic evaluation on the 5th postoperative day, and discharge home on the 7th postoperative day, with return to school within 2 weeks, and resumption of all gymnastic activity within 6 weeks of the minimally invasive surgery.Results:In those having a lower midline sternotomy, postoperative hospital stay was 7.4 ± 0.8 days, with return to school 8.0 ± 2.4 days after discharge. They resumed gymnastics 41 ± 11 days after the minimally invasive surgery. In those having a full sternotomy, in contrast, these parameters were 13.5 ± 2.7, 23.1 ± 8.4, and 95 ± 43 days, respectively. Of the 15 children undergoing a minimally invasive approach, 12 (80%) fulfilled the criterions of our clinical pathway.Conclusions:We conclude that minimally invasive cardiac surgery can safely be performed in children. In addition to its cosmetic role, the technique has added value in promoting early return to normal school life, including gymnastics.
Adequate left ventricular preparation allows for arterial switch despite late referral
Authors: Corno Antonio F. , Hurni Michel , Payot Maurice , Sekarski Nicole , Tozzi Piergiorgio , von Segesser Ludwig K.
Published: April 2005

Objective:To evaluate the feasibility of the arterial switch for surgical repair of transposition, defined as the combination of concordant atrioventricular and discordant ventriculo-arterial connections, after late referral.Methods:From March 2000 to August 2001, six children underwent an arterial switch procedure following left ventricular preparation because of late referral. The mean age at referral was 8.3 months, with a range from 3 to 25 months, and mean body weight was 5.3 kg, with a range from 3.7 to 9.3 kg. The mean saturation of oxygen was 57%, with a range from 50 to 72%. Associated defects included a restrictive ventricular septal defect in three patients, aortic coarctation in one, and partially anomalous pulmonary venous connection in one. The mean interval between referral and the arterial switch procedure was 3.7 months, within a range from 1 to 7 months. A mean of 1.5 surgical procedures were undertaken to prepare the left ventricle, the most being 3 procedures, including combinations of creation of an inter-atrial communication in four patients, banding of the pulmonary trunk in five, and creation of a systemic-to-pulmonary arterial shunt in three. We evaluated left ventricle ejection and shortening fractions, left ventricular diastolic diameter and volume, right and left ventricular wall thicknesses, and the ratio of right to left ventricular values by echocardiography at referral, immediately before, and one week after the arterial switch procedure.Results:All children are alive and well, with a mean follow-up of 17 months, ranging from 9 to 26 months. Echocardiography showed a statistically significant decrease of the ratio between right and left ventricular wall thicknesses, from 1.33 ± 0.26 at referral to 0.79 ± 0.08 before the switch procedure (p < 0.005). Left ventricular function was adequate after arterial switch, with a mean ejection fraction of 79.3%, ranging from 66 to 87%, and a mean shortening fraction of 41.7%, ranging from 30 to 49%.Conclusions:Despite late referral, and initially inadequate left ventricular volume and mural thickness, children with transposition can successfully be treated with the arterial switch procedure, provided that the left ventricle is adequately prepared, using echocardiography to monitor left ventricular morphology and function.
The current state of, and future prospects for, cardiac transplantation in children
Authors: Webber Steven A.
Published: April 2005

During the last two decades, several advances have resulted in marked improvement in medium-term survival, with excellent quality of life, in children undergoing cardiac transplantation. Improved outcomes reflect better selection of donors and recipients, increased surgical experience in transplantation for complex congenital heart disease, development of effective surveillance for rejection, and wider choice of immunosuppressive medications. Despite all of these advances, recipients continue to suffer from the adverse effects of non-specific immunosupression, including infections, induction of lymphoproliferative disorders and other malignancies, renal dysfunction, and other important end-organ toxicities. Furthermore, newer immunosuppressive regimes, thus far, appear to have had relatively little impact on the incidence of chronic rejection. Progress in our understanding of the immunologic mechanisms of rejection and graft acceptance should lead to more targeted immunosuppressive therapy and avoidance of non-specific immunosupression. The ultimate goal is to induce a state of tolerance, wherein the recipient will accept the allograft indefinitely, without the need for long-term immunusupression, and yet remain immuno-competent to all non-donor antigens. This quest is currently being realized in many animal models of solid organ transplantation, and offers great hope for the future.
Duplication of the tension apparatus of the tricuspid valve
Authors: Anil Sivadasan R. , Rao Suresh G. , Kumar Raman K.
Published: April 2005

We report an infant with a large perimembranous ventricular septal defect, who had two separate orifices in the tricuspid valve, each supported by separate cordal apparatus, detected incidentally during surgery.
Cardiac catheterisation in infants weighing less than 2500 grams
Authors: McMahon Colin J. , Price Jack F. , Salerno Jack C. , El-Said Howaida , Taylor Michael , Vargo Thomas A. , Nihill Michael R.
Published: April 2005

Objectives: To investigate the indications for, and outcome of, cardiac catheterisation in infants weighing less than 2500 g at a single institution over an 8-year period. Patients and Methods: We assessed all infants who were less than 2500 g at the time of cardiac catheterisation at Texas Children's Hospital from January 1993 to January 2001. Comparisons of morbidity and mortality were drawn with an equivalent number of infants of similar age weighing greater than 2500 g seen over the same period of time. Results: We performed interventional procedures in 22, and diagnostic catheterisations in 12 infants weighing less than 2500 g. Interventions included pulmonary valvoplasty in six patients, balloon angioplasty of critical coarctation in one, aortic valvoplasty in two, septostomy in ten, and coil occlusion of an arteriovenous malformation, redirection of a subclavian venous line, and coil occlusion of a patent arterial duct in one patient each. The median age at catheterisation was 5 days for children less than 2500 g, and 10 days for those above 2500 g. The median weights were 2.3 kg and 3.3 kg, and the median gestational ages were 35 weeks and 38 weeks, for the two respective groups. Of those weighing less than 2500 g, two died (6%), with no deaths occurring in those weighing more than 2500 g. In 3 patients weighing less than 2500 g (9%), there was vascular compromise, one child with bilateral femoral venous obstruction requiring fasciotomy compared, to one in the group weighing greater than 2500 g (2%). Conclusion: There is a significantly increased risk of mortality and vascular compromise in infants weighing less than 2500 g. Interventional catheterisation in these infants may be lifesaving, but given the aforementioned risks, diagnostic catheterisation should be deferred if possible in favor of noninvasive modalities.
The ratio of flow in the superior and inferior caval veins after construction of a bidirectional cavopulmonary anastomosis in children
Authors: Eyskens Benedicte , Mertens Luc , Kuzo Ronald , Jaegere Tom De , Lawrenson John , Dymarkowski Steven , Bogaert Jan , Daenen Willem , Gewillig Marc
Published: April 2005

In patients who have undergone a superior cavopulmonary anastomosis, the superior caval venous flow provides the only, or the most important, pulmonary blood supply, while the inferior caval venous blood is not oxygenated, being mixed with the pulmonary venous blood before entering the systemic circulation. In healthy children, the contribution of superior caval venous flow to total cardiac output has been shown to decrease during growth. Patients who have undergone a superior cavopulmonary anastomosis, however, often have a higher oxygen saturation than predicted by the age-matched ratio of superior to inferior caval venous flows. This study was designed, therefore, to assess the ratio of flows in the superior and inferior caval veins subsequent to a superior cavopulmonary anastomosis. We carried out 18 magnetic resonance imaging studies with velocity-mapping and heart catheterisations so as to assess the contribution of superior caval venous flow to total cardiac output. Patients were divided into 3 groups according to their age. There were five aged from 8 to 24 months, eight aged from 24 to 48 months, and five older than 48 months. No significant difference could be found in the ratios of superior-to-inferior caval venous flow, nor of superior caval venous-to-systemic flow, between the 3 groups. The ratio of venous flows was 0.89 ± 0.34 in those aged from 8 to 24 months, 1.09 ± 0.42 in those from 24 to 48 months, and 1.25 ± 0.27 in the older patients (F analysis of variance 1.06, p 0.37). The ratio of superior caval venous-to-systemic flow was 0.46 ± 0.08 in the youngest patients, 0.50 ± 0.09 in those aged from 24 to 48 months, and 0.55 ± 0.05 in the older patients (F analysis of variance 0.76, p 0.49). These findings suggest that the hemodynamics of a cavopulmonary anastomosis may affect the normal decrease of superior caval venous flow with age. This could be related to a redistribution of flow, with a proportionally higher flow to the head and upper body after construction of a superior cavopulmonary anastomosis. Since increasing cyanosis and progressive exercise intolerance are the main indications for creation of a total cavopulmonary connection, these findings should be taken into account when determining the timing for completion of the Fontan circulation.
A model for left juxtaposition of the atrial appendages in the chick
Authors: Männer Jörg , Heinicke Franziska
Published: April 2005

The morphogenesis of most types of human congenital cardiac malformations is still obscure. The reasons for this are, first, the paucity of data from human embryos and fetuses and, second, the paucity of appropriate animal models. During the past few years, we have tested several chemicals for their teratogenic potential, hoping to find, particularly in the chick, substances that could be used for the development of models for specific cardiac malformations. We have now discovered that suramin, an antitrypanosomal drug, can induce a special type of congenital cardiac defect in which the two atrial appendages are positioned to the left of the great arteries. This situation resembles the situation found in humans and classified as left juxtaposition of the atrial appendages. In the present study, we have analysed the pathomorphological features of a series of our chicken hearts to assess precisely how accurately these cardiac malformations in the chick correspond to the situation seen in the human. We found that the cases observed in the chick did, indeed, have many features in common with the human cases described in the literature. This suggests that we have developed an animal model for human left juxtaposition. Our model could be used for two kinds of embryological studies: first, documentation of the morphogenesis of left juxtaposition; and second, studies on the mechanisms driving the normal positional changes between the atriums and outflow tract of the embryonic heart during the late phase of cardiac looping. The fact that left juxtaposition of the atrial appendages can be induced by suramin might help to elucidate the molecular mechanisms underlying this type of congenital cardiac malformation. Furthermore, the fact that suramin is used for the chemotherapy of frequent tropical diseases, such as African trypanosomiasis and onchocerciasis, poses the question as to whether this drug might play a role in the aetiology of left juxtaposition in some human populations.
Kinetics of procalcitonin, interleukin 6 and C-reactive protein after cardiopulmonary-bypass in children
Authors: Beghetti Maurice , Rimensberger Peter C. , Kalangos Afksendiyos , Habre Walid , Gervaix Alain
Published: April 2005

Cardiopulmonary bypass induces a generalized inflammatory response, with fever and leukocytes, which is difficult to differentiate from an infection. Recently, procalcitonin has been proposed as an early and specific marker of bacterial infection. The influence of cardiopulmonary bypass on production of procalcitonin, therefore, must be assessed before considering this molecule as a valuable marker of infection after cardiac surgery in children. With this in mind, we measured levels of procalcitonin, interleukin 6, and C-reactive protein before and 6 h, 1, 3 and 5 days after cardiopulmonary bypass, in 25 children undergoing cardiac surgery. Cardiopulmonary-bypass induced a transient increase in procalcitonin, with a peak at 24 h, with a median of 1.13 μg/l, a 25th and 75th interquartile of 0.68–2.25, and a p value of less than 0.001. The value had returned to normal in the majority of the children by the third day after surgery. Peak values correlated with the duration of cardiopulmonary-bypass, with a r-value of 0.58 and a p value of 0.003; cross-clamp time, with a r-value of 0.62 and a p value of 0.001; days of mechanical ventilation, with a r-value of 0.62 and a p value of 0.001; and days of stay in intensive care, with a r-value of 0.68, and a p value of 0.0003. The value returned to normal after 3 days in 83% of the patients. Levels of interleukin 6 and C-reactive protein also increased significantly after surgery, and remained elevated for up to 5 days.

Thus, in contrast to other markers, levels of procalcitonin in the serum are only slightly and transiently influenced by cardiopulmonary bypass, and may prove to be useful in the early recognition of an infection subsequent to cardiopulmonary bypass.
Prenatal diagnosis of tetralogy of Fallot associated with a fistula from the left coronary artery to the left atrium
Authors: Khan Mohammed D. , Sivasubramonian Sivasankaran , Simpson John M.
Published: April 2005

In a fetus at 20 weeks gestation, we found a large fistula from the left coronary artery to the left atrium in association with tetralogy of Fallot. Postnatally, the therapeutic issues were complex because of prematurity, low birth weight, decreased flow of blood to the lungs, and volume overload of the left ventricle because of the huge fistula. At three months, the baby underwent repair of tetralogy of Fallot, with surgical ligation of the fistula, but the baby died postoperatively.
Unusual interventional management in an adult with tetralogy of Fallot
Authors: Abdel-Massih Tony , Boudjemline Younes , Bonhoeffer Philipp
Published: April 2005

A 53-year-old man with tetralogy of Fallot had been palliated with two classic Blalock-Taussig shunts. Cardiac catheterization in our center revealed acquired atresia of the pulmonary valve. We perforated and dilated the valve as a palliative procedure with a new system using radiofrequency energy.
Broadband VLF measurements of lightning‐induced ionospheric perturbations
Authors: Cheng Zhenggang , Cummer Steven A.
Published: April 2005

Very low frequency (VLF) electromagnetic pulses radiated by lightning are an effective tool for probing the D region ionosphere. We detect and measure the D region ionospheric disturbances caused by the strong lightning flash by analyzing the broadband VLF spectrum from lightning that occurred just before and after a nearby intense lightning discharge. Comparing the measured electron density changes to those from previous measurements and the theoretical expectations, we find the detected perturbations are consistent with the theoretically predicted ionization changes produced directly by the lightning electromagnetic pulse.
Contiguous rupture areas of two Nankai Trough earthquakes revealed by high‐resolution tsunami waveform inversion
Authors: Baba Toshitaka , Cummins Phil R.
Published: April 2005

We have developed a new method for inverting tsunami waveforms that reveals considerable detail in megathrust slip during subduction zone earthquakes. Previous methods have ensured compliance with the shallow‐water theory used to compute tsunami waveforms by using large subfaults that generate only long‐wavelength seafloor deformation. We show that a better approach is to use small subfaults coupled with a smoothing criterion that ensures compliance with the shallow‐water approximation. In an application of the method to historical earthquakes in the Nankai Trough, southwestern Japan, we find that the areas with slip > 1 m for the earthquakes of 1944 and 1946, which ruptured adjacent segments of the subduction zone, are separated by a sharp, non‐overlapping boundary. This establishes that interseismic accumulation of strain energy extends very close to the boundary between rupture zones, and strongly suggests that this boundary is associated with a physical barrier to rupture.
Evidence for triggering of the Vogtland swarms 2000 by pore pressure diffusion
Authors: Parotidis M. , Shapiro S. A. , Rothert E.
Published: April 2005

Seismicity triggered by fluid injection in boreholes usually has certain typical spatiotemporal characteristics. These characteristics can be partly recognized as signatures, when pore pressure diffusion is the dominant triggering mechanism. Starting from these diffusion‐typical signatures of man‐made earthquakes, we seek analogous patterns for the earthquakes in Vogtland/NW Bohemia (VB) at the German/Czech border region in central Europe. VB is characterized by recurring intraplate earthquake swarms with magnitudes up to ML 4.5. There is strong geophysical evidence that the seismic events are correlated to fluid‐related processes in the crust. This study aims to investigate the possible role of fluids in VB. We test the hypothesis that ascending magmatic fluids trigger earthquakes by the mechanism of pore pressure diffusion (i.e., relaxation). This triggering process is mainly controlled by two physical fields, the hydraulic diffusivity and the seismic criticality (i.e., critical pore pressure value leading to failure; stable locations are characterized by higher critical pressures), both heterogeneously distributed in rocks. The results of the analysis of the year 2000 VB earthquake swarm data support this concept. We were able to recognize diffusive signatures and to obtain scalar estimates of hydraulic diffusivities with values between 0.3 and 10 m2/s for the seismically active region. Using a numerical model, where spatially correlated diffusivity and criticality patches (where patches with higher diffusivity are assumed to be less stable) are considered, we successfully simulate a general seismicity pattern of the swarms 2000, including the spatiotemporal clustering of events and the migration of seismic activity.
Effect of gravitational consistency and mass conservation on seasonal surface mass loading models
Authors: Clarke P. J. , Lavallée D. A. , Blewitt G. , van Dam T. M. , Wahr J. M.
Published: April 2005

Increasingly, models of surface mass loads are used either to correct geodetic time coordinates by removing seasonal and other “noise”, or for comparison with other geodetic parameters. However, models of surface loading obtained by simply combining the mass redistribution due to individual phenomena will not in general be self‐consistent, in that (i) the implied global water budget will not be mass‐conserving, and (ii) the modelled sea level will not be an equipotential surface of Earth's total gravity field. We force closure of the global water budget by allowing the “passive” ocean to change in mass. This medium‐term passive ocean response will not be a uniform change in non‐steric ocean surface height, but must necessarily be spatially variable to keep the “passive” ocean surface on an equipotential. Using existing load models, we demonstrate the effects of our consistency theory. Geocenter motion is amplified significantly, by up to 43%.
Tramadol produces outward currents by activating μ‐opioid receptors in adult rat substantia gelatinosa neurones
Authors: Koga Akiko , Fujita Tsugumi , Totoki Tadahide , Kumamoto Eiichi
Published: April 2005

An action of a tramadol metabolite, mono‐O‐dimethyl‐tramadol (M1), on substantia gelatinosa (SG) neurones in adult rat spinal cord slices was examined by using the whole‐cell patch‐clamp technique.

In 41% of the neurones examined, superfusing M1 produced an outward current at −70 mV; this response reversed at a potential close to the equilibrium potential for K+. M1 current hardly declined and persisted for >30 min after its washout.

M1 current correlated in amplitude with current produced by μ‐opioid receptor agonist DAMGO in the same neurone, and largely reduced in amplitude in the presence of μ‐opioid receptor antagonist CTAP but not α2‐adrenoceptor antagonist yohimbine. In a neurone where M1 had no effect on holding currents, noradrenaline produced an outward current at −70 mV.

The amplitude of the M1 response, relative to that of the DAMGO response, exhibited an EC50 value of 300 μM.

We conclude that M1 produces a persistent hyperpolarization by activating μ‐opioid receptors in adult rat SG neurones. This could contribute to at least a part of pain alleviation produced by tramadol.

British Journal of Pharmacology (2005) 145, 602–607. doi:10.1038/sj.bjp.0706225
Increased αCGRP potency and CGRP‐receptor antagonist affinity in isolated hypoxic porcine intramyocardial arteries
Authors: Hasbak Philip , Eskesen Karen , Schifter Søren , Edvinsson Lars
Published: April 2005

This study describes the effects of hypoxia on relaxing responses and cAMP production induced by the known vasodilator peptides: αCGRP, amylin (AMY) and adrenomedullin (AM) on isolated pig coronary arteries in vitro.

Hypoxic incubation increased the vasorelaxant effect of αCGRP (four‐fold; P<0.05), AMY (3.2‐fold; P<0.05), but not significantly for AM (two‐fold; NS).

Whereas hypoxia had no effect on arterial cAMP levels, it significantly potentiated the production of cAMP stimulated of αCGRP and AMY, but not of AM.

The antagonist αCGRP8–37 also exerted an increased effect in hypoxia. The Schild plot‐derived pKB values revealed an increase in the apparent affinity of the antagonist for the CGRP1 receptor from 7.0 to 7.2 under control conditions versus 8.0 in hypoxia.

Removal of endothelium, peptidase inhibitors, preincubation with the adenosine A2A receptor antagonist CSC (10−3 M), the ATP‐sensitive K‐channel inhibitor glibenclamide (10−5 M), the cyclooxygenase inhibitor indomethacin (10−3 M) or NG‐monomethyl‐L‐arginine (10−4 M) had no effect on the αCGRP‐induced vasorelaxation in hypoxia; neither did hypoxia influence the levels of CGRP and AM receptor mRNA.

We conclude that hypoxic incubation increases the relaxation and cAMP production induced by αCGRP and AMY in rings of porcine coronary arteries in vitro. A concomitant release of adenosine, a cyclooxygenase product, an endothelium‐derived substance, activation of vascular ATP‐sensitive K‐channels, peptidase inhibitors or changes in CGRP and AM receptor mRNA cannot account for the changes observed in hypoxia. Moreover, αCGRP8–37 showed increased affinity at the CGRP1 receptor during hypoxia, possibly due to a conformational change at the CGRP1 receptor site.

British Journal of Pharmacology (2005) 145, 646–655. doi:10.1038/sj.bjp.0706232
Finite jellium models. I. Restricted Hartree–Fock calculations
Authors: Ghosh Sankha , Gill Peter M. W.
Published: April 2005

Restricted Hartree–Fock calculations have been performed on the Fermi configurations of n electrons confined within a cube. The self-consistent-field orbitals have been expanded in a basis of N particle-in-a-box wave functions. The difficult one- and two-electron integrals have been reduced to a small set of canonical integrals that are calculated accurately using quadrature. The total energy and exchange energy per particle converge smoothly toward their limiting values as n increases; the highest occupied molecular orbital–lowest unoccupied molecular orbital gap and Dirac coefficient converge erratically. However, the convergence in all cases is slow.
Hopping conductivity in Cr-doped β-FeSi2 single crystals
Authors: Lisunov K. G. , Arushanov E. , Vinzelberg H. , Behr G. , Schumann J.
Published: April 2005

The resistivity of Cr-doped p-type β-FeSi2 single crystals has been investigated in the temperature interval of T=4.2–300K. The data are analyzed within the framework of the variable-range hopping (VRH) mechanism for both the Mott and the Shklovskii–Efros regimes. With decreasing temperature a crossover between the Mott and the Shklovskii–Efros VRH conductivity regimes is observed. It is shown that the temperature dependence of the resistivity, ρ (T), of Cr-doped β-FeSi2 crystals, that follows a VRH conductivity mechanism, obeys a scaling law ln(ρ∕ρ0)=Af(T∕Tx). The values of the characteristic (T0) and the transition temperatures (Tv), as well as the width of the soft Coulomb gap Δ in the spectrum of the density of the localized states (DOS) are determined. The observed values of the VRH transition and characteristic temperatures indicate the existence of a rigid gap δ in the spectrum of the DOS in addition to Δ. This points to the polaronic nature of the charge carriers in the investigated compound.
Coulomb explosion of ammonia clusters induced by intense nanosecond laser at 532 and 1064nm: Wavelength dependence of the multicharged nitrogen ions
Authors: Niu Dongmei , Li Haiyang , Liang Feng , Wen Lihua , Luo Xiaolin , Wang Bin , Qu Hongbo
Published: April 2005

The Coulomb explosion of ammonia clusters induced by nanosecond laser field with intensity in the range of 1010–1012Wcm−2 and wavelength of 532 and 1064nm has been studied. N2+ and N3+ ions are the main multicharged ions at 532nm, while He-like N5+ ion is the domain multicharged ion at 1064nm.
CdS nanobelts as photoconductors
Authors: Gao T. , Li Q. H. , Wang T. H.
Published: April 2005

Mass production of single-crystalline CdS nanobelts is achieved by thermal evaporation of CdS powders with the presence of Au catalyst. The as-synthesized CdS nanobelts are usually hundreds of nanometers to tens of micrometers in width, tens of nanometers in thickness, and several hundreds of micrometers in length. CdS nanobelts have a pronounced increase in conductance of up to four orders of magnitude upon exposure to white light, and also very fast response time about 1–3 s. The photoconductivity mechanism of CdS nanobelts is discussed. The results demonstrate the potential of fabricating nanosized photoconductors and optical switches using the integrity of a single CdS nanobelt.
Unidirectional beam emission from strained InGaAsP multiple-quantum-well quasistadium laser diodes
Authors: Fukushima Takehiro , Tanaka Tomoko , Harayama Takahisa
Published: April 2005

We present unidirectional emission from strained InGaAsP multiple-quantum-well quasistadium laser diodes, whose resonators consist of two confocal end mirrors and two long, straight, sidewall mirrors. Far-field patterns exhibit highly directional emission at a 20° angle from the cavity axis. This angle corresponds to a unidirectional ring trajectory inside the resonator. We also report that the unidirectional emission can be explained by the phase locking of two resonator modes with different symmetry classes based on the extended Fox-Li mode calculation method.
Crystal structure of prostate-specific membrane antigen, a tumor marker and peptidase
Authors: Davis Mindy I. , Bennett Melanie J. , Thomas Leonard M. , Bjorkman Pamela J.
Published: April 2005

Prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer cells and nonprostatic solid tumor neovasculature and is a target for anticancer imaging and therapeutic agents. PSMA acts as a glutamate carboxypeptidase (GCPII) on small molecule substrates, including folate, the anticancer drug methotrexate, and the neuropeptide
N
-acetyl-
l
-aspartyl-
l
-glutamate. Here we present the 3.5-Å crystal structure of the PSMA ectodomain, which reveals a homodimer with structural similarity to transferrin receptor, a receptor for iron-loaded transferrin that lacks protease activity. Unlike transferrin receptor, the protease domain of PSMA contains a binuclear zinc site, catalytic residues, and a proposed substrate-binding arginine patch. Elucidation of the PSMA structure combined with docking studies and a proposed catalytic mechanism provides insight into the recognition of inhibitors and the natural substrate
N
-acetyl-
l
-aspartyl-
l
-glutamate. The PSMA structure will facilitate development of chemotherapeutics, cancer-imaging agents, and agents for treatment of neurological disorders.
An anti-CD45RO/RB monoclonal antibody modulates T cell responses via induction of apoptosis and generation of regulatory T cells
Authors: Gregori Silvia , Mangia Patrizia , Bacchetta Rosa , Tresoldi Eleonora , Kolbinger Frank , Traversari Catia , Carballido Josè M. , de Vries Jan E. , Korthäuer Ulf , Roncarolo Maria-Grazia
Published: April 2005

The effects of a chimeric monoclonal antibody (chA6 mAb) that recognizes both the RO and RB isoforms of the transmembrane protein tyrosine phosphatase CD45 on human T cells were investigated. Chimeric A6 (chA6) mAb potently inhibited antigen-specific and polyclonal T cell responses. ChA6 mAb induced activation-independent apoptosis in CD4+CD45RO/RBhigh T cells but not in CD8+ T cells. In addition, CD4+ T cell lines specific for tetanus toxoid (TT) generated in the presence of chA6 mAb were anergic and suppressed the proliferation and interferon (IFN)-γ production by TT-specific effector T cells by an interleukin-10–dependent mechanism, indicating that these cells were equivalent to type 1 regulatory T cells. Similarly, CD8+ T cell lines specific for the influenza A matrix protein-derived peptide (MP.58-66) generated in the presence of chA6 mAb were anergic and suppressed IFN-γ production by MP.58-66–specific effector CD8+ T cells. Furthermore, chA6 mAb significantly prolonged human pancreatic islet allograft survival in nonobese diabetic/severe combined immunodeficiency mice injected with human peripheral blood lymphocytes (hu-PBL-NOD/SCID). Together, these results demonstrate that the chA6 mAb is a new immunomodulatory agent with multiple modes of action, including deletion of preexisting memory and recently activated T cells and induction of anergic CD4+ and CD8+ regulatory T cells.
Structural and kinetic basis for heightened immunogenicity of T cell vaccines
Authors: Chen Ji-Li , Stewart-Jones Guillaume , Bossi Giovanna , Lissin Nikolai M. , Wooldridge Linda , Choi Ed Man Lik , Held Gerhard , Dunbar P. Rod , Esnouf Robert M. , Sami Malkit , Boulter Jonathan M. , Rizkallah Pierre , Renner Christoph , Sewell Andrew , van der Merwe P. Anton , Jakobsen Bent K. , Griffiths Gillian , Jones E. Yvonne , Cerundolo Vincenzo
Published: April 2005

Analogue peptides with enhanced binding affinity to major histocompatibility class (MHC) I molecules are currently being used in cancer patients to elicit stronger T cell responses. However, it remains unclear as to how alterations of anchor residues may affect T cell receptor (TCR) recognition. We correlate functional, thermodynamic, and structural parameters of TCR–peptide–MHC binding and demonstrate the effect of anchor residue modifications of the human histocompatibility leukocyte antigens (HLA)–A2 tumor epitope NY–ESO-1157–165–SLLMWITQC on TCR recognition. The crystal structure of the wild-type peptide complexed with a specific TCR shows that TCR binding centers on two prominent, sequential, peptide sidechains, methionine–tryptophan. Cysteine-to-valine substitution at peptide position 9, while optimizing peptide binding to the MHC, repositions the peptide main chain and generates subtly enhanced interactions between the analogue peptide and the TCR. Binding analyses confirm tighter binding of the analogue peptide to HLA–A2 and improved soluble TCR binding. Recognition of analogue peptide stimulates faster polarization of lytic granules to the immunological synapse, reduces dependence on CD8 binding, and induces greater numbers of cross-reactive cytotoxic T lymphocyte to SLLMWITQC. These results provide important insights into heightened immunogenicity of analogue peptides and highlight the importance of incorporating structural data into the process of rational optimization of superagonist peptides for clinical trials.
Natural selection drives recurrent formation of activating killer cell immunoglobulin-like receptor and Ly49 from inhibitory homologues
Authors: Abi-Rached Laurent , Parham Peter
Published: April 2005

Expression of killer cell Ig-like receptors (KIRs) diversifies human natural killer cell populations and T cell subpopulations. Whereas the major histocompatibility complex class I binding functions of inhibitory KIR are known, specificities for the activating receptors have resisted analysis. To understand better activating KIR and their relationship to inhibitory KIR, we took the approach of reconstructing their natural history and that of Ly49, the analogous system in rodents. A general principle is that inhibitory receptors are ancestral, the activating receptors having evolved from them by mutation. This evolutionary process of functional switch occurs independently in different species to yield activating KIR and Ly49 genes with similar signaling domains. Selecting such convergent evolution were the signaling adaptors, which are older and more conserved than any KIR or Ly49. After functional shift, further activating receptors form through recombination and gene duplication. Activating receptors are short lived and evolved recurrently, showing they are subject to conflicting selections, consistent with activating KIR's association with resistance to infection, reproductive success, and susceptibility to autoimmunity. Our analysis suggests a two-stage model in which activating KIR or Ly49 are initially subject to positive selection that rapidly increases their frequency, followed by negative selection that decreases their frequency and leads eventually to loss.