bluuebunny/crossref_metadata_2025 huggingface dataset:
On the performance of molecular polarization methods. II. Water and carbon tetrachloride close to a cation
Authors: Masia Marco , Probst Michael , Rey Rossend
Published: October 2005

Our initial study on the performance of molecular polarization methods close to a positive point charge [M. Masia, M. Probst, and R. Rey, J. Chem. Phys. 121, 7362 (2004)] is extended to the case in which a molecule interacts with a real cation. Two different methods (point dipoles and shell model) are applied to both the ion and the molecule. The results are tested against high-level ab initio calculations for a molecule (water or carbon tetrachloride) close to Li+, Na+, Mg2+, and Ca2+. The monitored observable is in all cases the dimer electric dipole as a function of the ion-molecule distance for selected molecular orientations. The moderate disagreement previously obtained for point charges at intermediate distances, and attributed to the linearity of current polarization methods (as opposed to the nonlinear effects evident in ab initio calculations), is confirmed for real cations as well. More importantly, it is found that at short separations the phenomenological polarization methods studied here substantially overestimate the dipole moment induced if the ion is described quantum chemically as well, in contrast to the dipole moment induced by a point-charge ion, for which they show a better degree of accord with ab initio results. Such behavior can be understood in terms of a decrease of atomic polarizabilities due to the repulsion between electronic charge distributions at contact separations. It is shown that a reparametrization of the Thole method for damping of the electric field, used in conjunction with any polarization scheme, allows to satisfactorily reproduce the dimer dipole at short distances. In contrast with the original approach (developed for intramolecular interactions), the present reparametrization is ion and method dependent, and corresponding parameters are given for each case.
On the control of product yields in the photofragmentation of deuteriumchlorid ions (DCl+)
Authors: Korolkov Mikhail V. , Weitzel Karl-Michael
Published: October 2005

The prospect of controlling the photofragmentation of deuterium chloride ions (DCl+) via strong ultrashort IR laser pulses has been investigated by a numerical solution of coupled Schrödinger equations. The calculations provide evidence that the ratio of product ion yields Cl+ versus D+ can be manipulated by an appropriate choice of laser pulse parameters, in particular, central laser frequency, pulse duration, intensity, and chirp. The analysis of time-dependent populations reveals competition between intra- and interelectronic state excitations, enabling the understanding of quantum control at the molecular level.
Formation of a density blob and its dynamics in the edge and the scrape-off layer of a tokamak plasma
Authors: Bisai N. , Das A. , Deshpande S. , Jha R. , Kaw P. , Sen A. , Singh R.
Published: October 2005

Formation of a density blob and its motion in the edge and scrape-off layer (SOL) of a tokamak plasma have been simulated using two-dimensional, two-field, fluid model equations. The simulation results show that density blobs form in the edge or in the edge-to-SOL transition region where the poloidal velocity shear is maximum. From the numerical data, a condition for density blob formation has been obtained. Dynamics of the detached blob in the edge and SOL regions has been studied. It is observed that not all the blobs that form in the edge or edge-to-SOL transition region are capable of ejection deep into the SOL. A condition for their ejection is also discussed. Radial particle transport associated with the blobs in the SOL has been calculated. It is found that about 60% of the total radial particle flux is carried out by these blobs.
A simple theory of molecular organization in fullerene-containing liquid crystals
Authors: Peroukidis S. D. , Vanakaras A. G. , Photinos D. J.
Published: October 2005

Systematic efforts to synthesize fullerene-containing liquid crystals have produced a variety of successful model compounds. We present a simple molecular theory, based on the interconverting shape approach [Vanakaras and Photinos, J. Mater. Chem. 15, 2002 (2005)], that relates the self-organization observed in these systems to their molecular structure. The interactions are modeled by dividing each molecule into a number of submolecular blocks to which specific interactions are assigned. Three types of blocks are introduced, corresponding to fullerene units, mesogenic units, and nonmesogenic linkage units. The blocks are constrained to move on a cubic three-dimensional lattice and molecular flexibility is allowed by retaining a number of representative conformations within the block representation of the molecule. Calculations are presented for a variety of molecular architectures including twin mesogenic branch monoadducts of C60, twin dendromesogenic branch monoadducts, and conical (badminton shuttlecock) multiadducts of C60. The dependence of the phase diagrams on the interaction parameters is explored. In spite of its many simplifications and the minimal molecular modeling used (three types of chemically distinct submolecular blocks with only repulsive interactions), the theory accounts remarkably well for the phase behavior of these systems.
In situ imaging of micro-organisms in intense magnetic fields
Authors: Guevorkian Karine , Valles James M
Published: October 2005

This article describes a setup suitable for the in situ visualization and imaging of swimming unicellular organisms in intense magnetic fields at a constant temperature. It fits within a 31 T maximum field, 50 mm bore resistive magnet at the National High Magnetic Field Laboratory. The main optical component is a 6 mm side view borescope, which provides an optical axis perpendicular to the magnetic field allowing us to monitor the motion of the micro-organisms parallel to the field. The system has a maximum resolution of 20μm. We will present images of swimming paramecia in magnetic field obtained with this setup and show that the resolution is adequate for tracking purposes.
Nanoscale potential distribution across multiquantum well structures: Kelvin probe force microscopy and secondary electron imaging
Authors: Schwarzman A. , Grunbaum E. , Strassburg E. , Lepkifker E. , Boag A. , Rosenwaks Y. , Glatzel Th. , Barkay Z. , Mazzer M. , Barnham K.
Published: October 2005

Ultrahigh vacuum cross-sectional Kelvin probe force microscopy has been used to characterize In0.17GaAs∕GaAsP0.06 multiquantum well structures, together with secondary electron microscopy. Individual 8nm quantum wells were well resolved in both methods, and were found to be in a good agreement with numerical simulations of the work function profile. It is shown that the surface potential contrast in the Kelvin probe force microscopy measurements is greatly enhanced using deconvolution algorithms, and the reasons for the different contrast in the electron microscopy images are discussed.
Observation of large Hall sensitivity in thin Fe–Ge amorphous composite films
Authors: Liu Hui , Zheng R. K. , Zhang X. X.
Published: October 2005

Amorphous FexGe1−x films with different metal volume fractions (0.40<x<1.00) and film thicknesses 4–300nm were fabricated by a cosputtering method. Magnetic and magnetotransport measurements indicated that the Fe–Ge films are ferromagnetic even above room temperature. A Hall sensitivity as large as 82V∕AT was obtained in the Fe0.67Ge0.33 film with a thickness of 4.1nm. More importantly, it was found that the Hall sensitivity does not depend on the temperature in the temperature range of 50–300K. In addition, the Hall resistance depends linearly on the magnetic field within the range of −2.5–2.5kOe. This linear dependence, the larger sensitivity, and its temperature independence indicate that Fe–Ge films are potential material candidates for field sensors in a very broad temperature range.
Strain relaxation due to V-pit formation in InxGa1−xN∕GaN epilayers grown on sapphire
Authors: Song T. L.
Published: October 2005

Strain relaxation in semiconductor heterostructures generally occurs through the motion of dislocations that generates misfit dislocations above a critical thickness. However, majority of the threading dislocations in GaN-related materials have no driving force to glide, and those with a driving force are kinetically impeded even at a temperature of 1000 °C. In spite of this, the strain in InxGa1−xN∕GaN epilayers grown on c-plane sapphire substrates was observed to decrease as the InxGa1−xN layer becomes thicker. We have explored the possibility of V-pit formation at terminated dislocations as the predominant relaxation mechanism in highly mismatched systems such as InxGa1−xN∕GaN. We demonstrate that a driving force exists to nucleate V pits for strain relief. The formation of V pits was modeled through the energy balance between the strain energy in the InxGa1−xN epilayer, the destruction of dislocation energy to form V pits and the strain that is relieved due to the formation of edges during the process of nucleating V pits in thermal equilibrium. V-pit formation and growth lead to strain relief as the film becomes thicker. The model illustrates many features that correlate reasonably well with experimental observations; the most significant trends are a rise in V-pit density and a decrease in strain with increasing layer thickness.
Electron transport through hierarchical self-assembly of GaAs∕AlxGa1−xAs quantum dots
Authors: Li Shu-Shen , Xia Jian-Bai , Hirose Kenji
Published: October 2005

The transmission of electrons through a hierarchical self-assembly of GaAs∕AlxGa1−xAs quantum dots (QDs) is calculated using the coupled-channel recursion method. Our results reveal that the number of conductance peaks does not change when the barrier widths change, but the intensities decrease as the barrier widths increase. The conductance peaks will shift towards low Fermi energies as the transverse width of GaAs QD increases, as the thickness of GaAs quantum well increases, or as the height of GaAs QDs decreases. Our calculated results may be useful in the application of QDs to photoelectric devices.
Characterization and analysis of single-mode high-power continuous-wave quantum-cascade laser
Authors: Bewley W. W. , Vurgaftman I. , Kim C. S. , Meyer J. R. , Nguyen J. , Evans A. , Yu J. S. , Darvish S. R. , Slivken S. , Razeghi M.
Published: October 2005

We measured and modeled the performance characteristics of a distributed-feedback quantum-cascade laser exhibiting high-power continuous-wave (CW) operation in a single spectral mode at λ≈4.8μm and temperatures up to 333K. The sidemode suppression ratio exceeds 25dB, and the emission remains robustly single mode at all currents and temperatures tested. CW output powers of 99mW at 298K and 357mW at 200K are obtained at currents well below the thermal rollover point. The slope efficiency and subthreshold amplified spontaneous emission spectra are shown to be consistent with a coupling coefficient of no more than κL≈4–5, which is substantially lower than the estimate of 9 based on the nominal grating fabrication parameters.
Study of organic polymer thin-film etching by plasma beam irradiation
Authors: Kurihara Kazuaki , Egami Akihiro , Nakamura Moritaka
Published: October 2005

We investigated the etching characteristics of three kinds of methacrylate polymer films which have the same main chain with a different side chain using a plasma beam irradiation apparatus. The polymers are polytbutylmethacrylate (PtBuMA), polybenzylmethacrylate (PBMA), and polycyclohexylmethacrylate (PCHMA). The etch yield (EY) of PtBuMA was higher than those of the others in the case of N2 plasma beam. The EYs of PBMA and PCHMA increased with an increase in the ion energy of up to 330eV and saturated at over 330eV. On the other hand, that of PtBuMA was almost constant at the ion energy higher than 130eV. It was supposed that nitridation of the polymer plays an important role in the enhancement of etching by N2 plasma. In the case of Ar plasma, EY increased linearly with an increase in the square root of ion energy for every polymer. In the case of H2 plasmas, EY scarcely depended on the ion energy regardless of the polymers. Etching behaviors with Ar and H2 plasma irradiation showed physical sputtering and chemical sputtering, respectively. The order of the magnitude of EY was PtBuMA, PCHMA, and PBMA for all of the Ar, H2, and N2 plasmas.
Three-dimensional modeling of electron quasiviscous dissipation in guide-field magnetic reconnection
Authors: Hesse Michael , Kuznetsova Masha , Schindler Karl , Birn Joachim
Published: October 2005

A numerical study of guide-field magnetic reconnection in a three-dimensional model is presented. Starting from an initial, perturbed, force-free current sheet, it is shown that reconnection develops to an almost translationally invariant state, where magnetic perturbations are aligned primarily along the main current flow direction. An analysis of guide-field and electron flow signatures indicates behavior that is very similar to earlier, albeit not three-dimensional, simulations. Furthermore, a detailed investigation of electron pressure nongyrotropies in the central diffusion region confirms the major role the associated dissipation process plays in establishing the reconnection electric field.
Transition from ferromagnetism to antiferromagnetism in Ga1−xMnxN
Authors: Dalpian Gustavo M. , Wei Su-Huai
Published: October 2005

Using density-functional theory, we study the magnetic stability of the Ga1−xMnxN alloy system. We show that unlike Ga1−xMnxAs, which shows only ferromagnetic phase, Ga1−xMnxN can be stable in either ferromagnetic or antiferromagnetic phases depending on the alloy concentration. The magnetic order can also be altered by applying pressure or with charge compensation. A band-structure model is used to explain these behaviors.
Broadband complex permittivity measurement techniques of materials with thin configuration at microwave frequencies
Authors: Murata Ken-ichiro , Hanawa Akio , Nozaki Ryusuke
Published: October 2005

A test method to evaluate the complex permittivity of materials with thin configuration (thickness of 50–300μm) is presented. We evaluate the complex permittivity of materials with various mechanical and electrical characteristics (films, powders, and liquids) at frequencies from 100 MHz to 20 GHz and at temperatures from 293 to 353 K using an experimental method presented in this paper. We have developed a fixture having a circular parallel-plate capacitor which is suitable for the measurement of materials with thin configuration. Our method is based on theoretical consideration of wave propagation in the capacitor, which is associated with multiple reflections along the diameter of the sample. The consideration of time delay in the sample section makes it possible to evaluate the permittivity of high dielectric constant materials in the frequency range up to 20 GHz. In addition, some examples for the measurements show that the resolution with tanδ is as low as 0.001. Our method is powerful to understand the relation between dielectric properties and the microscopic dynamics of dielectric materials, because of the broadband measurement, and finally can be applied for various areas both in fundamental researches and practical applications.
Self-consistent calibration of photoluminescence and photoconductance lifetime measurements
Authors: Trupke T. , Bardos R. A. , Abbott M. D.
Published: October 2005

An experimental method is introduced by which relative photoluminescence or photoconductance signals can be converted into an absolute excess carrier concentration. This method is demonstrated by comparison of self-consistently calibrated quasi-steady-state photoluminescence measurements with transient photoluminescence and with transient and quasi-steady-state photoconductance measurements on silicon samples. The method simplifies photoluminescence lifetime measurements and the recently introduced Suns-photoluminescence technique as it allows these techniques to be used in a self-contained way, without the previous requirement for a separate experimental technique for calibration. Important experimental observations regarding photoconductance lifetime measurements are also discussed.
Frequency dispersion of ultrasonic velocity and attenuation of longitudinal waves propagating in 0.68Pb(Mg1∕3Nb2∕3)O3–0.32PbTiO3 single crystals poled along [001] and [110]
Authors: Zhang Rui , Jiang Wenhua , Cao Wenwu
Published: October 2005

Using ultrasonic spectroscopy, the frequency dispersion of ultrasonic velocity and attenuation in the frequency range of 50–110MHz were measured for longitudinal waves propagating in 0.68Pb(Mg1∕3Nb2∕3)O3–0.32PbTiO3 (PMN-32%PT) single crystals poled along [001] and [110], respectively. The measured dispersion of longitudinal wave velocity and attenuation in the multidomain PMN-32%PT crystals are smaller than that of PZT-4 but much higher than that of PMN-28%PT poled along [001]. The correlation between larger piezoelectric coefficient and higher attenuation of ultrasonic waves in multiple-domain (1−x)Pb(Mg1∕3Nb2∕3)O3–xPbTiO3 single crystal for compositions closer to the morphotropic phase boundary indicates that the physical origin of the higher piezoelectric activity is associated with higher density of non-180° domain walls.
Improved GaN layer morphology by hydride vapor phase epitaxy on misoriented Al2O3 wafers
Authors: Scholz Ferdinand , Brückner Peter , Habel Frank , Peter Matthias , Köhler Klaus
Published: October 2005

Crack-free thick GaN layers have been grown by hydride vapor phase epitaxy on on-axis as well as on off-axis GaN-Al2O3 templates. A dramatic difference in surface quality could be traced back to the misorientation of the substrates: Mirror-like layers have been obtained for slightly off-oriented substrates, whereas pyramids and other surface structures were found on samples grown on exactly oriented wafers. Such excellent surfaces may make further surface treatment prior to a subsequent use of these wafers in further epitaxial processes obsolete.
Colony specific variation in the use of a moulting site in the migratory little tern Sterna albifrons
Authors: Tavecchia Giacomo , Baccetti Nicola , Serra Lorenzo
Published: October 2005

Individual‐based data on little terns Sterna albifrons at a post‐breeding moulting area were used to investigate the spatial extent at which this site attract birds. Combining information collected on young terns, ringed at the natal colonies, with that on birds captured a few months later at the moulting site, we estimated a survival/movement parameter for each age‐by‐colony combination. This parameter is the product between the survival probability and the probability to visit the moulting site. The distance between the natal colony and the moulting site negatively influenced the probability of reaching the site in yearlings. Having corrected for the distance from the moulting area, colony characteristics explained only about 10% of the spatial variation in the survival/movement parameter of juveniles. In older birds that had visited the site at least once in their life, neither the colony nor the distance affected the survival/movement parameter significantly. The average annual adult survival/movement probability was 0.90. Juvenile survival between June and September was 0.60. Overall results suggest that the moulting area could act as a ‘population funnel’ within a system of moult migration that involves birds breeding up to 500 km away. However, other unknown moulting site must exist within this area that could be important for the conservation of the species.
Systematic review: acute colonic pseudo‐obstruction
Authors: SAUNDERS M. D. , KIMMEY M. B.
Published: October 2005

Acute colonic pseudo‐obstruction is the clinical syndrome of acute large bowel dilatation without mechanical obstruction that is an important cause of morbidity and mortality. Acute colonic pseudo‐obstruction occurs in hospitalized or institutionalized patients with serious underlying medical and surgical conditions.

The pathogenesis of acute colonic pseudo‐obstruction is not completely understood but likely results from an imbalance in the autonomic regulation of colonic motor function. Metabolic or pharmacological factors, as well as spinal or retroperitoneal trauma, may alter the autonomic regulation of colonic function, leading to excessive parasympathetic suppression or sympathetic stimulation. This imbalance results in colonic atony and dilatation.

Early recognition and appropriate management are critical to minimizing morbidity and mortality. The mortality rate is estimated at 40% when ischaemia or perforation occurs. The best‐studied treatment of acute colonic pseudo‐obstruction is intravenous neostigmine, which leads to prompt colon decompression in the majority of patients after a single infusion. In patients failing or having contraindications to neostigmine, colonoscopic decompression is the active intervention of choice. Surgery is reserved for those with peritonitis or perforation.
Low rectal volumes in patients suffering from fecal incontinence: what does it mean?
Authors: SIPROUDHIS L. , EL ABKARI M. , EL ALAOUI M. , JUGUET F. , BRETAGNE J. F.
Published: October 2005

Background : Rectal perception and adaptation to distension are widely heterogeneous in subjects with faecal incontinence.

Aim : To quantify rectal physiology in patients with incontinence and low maximum rectal volume, according to AGA guidelines on anorectal testing techniques.

Patients and methods : 148 patients (12 men, 136 female) with incontinence to liquid and/or solid stools were investigated. Distending isobaric procedures were carried out using an electronic barostat in order to analyse perception and adaptation of the rectum.

Results : Pain during isovolumic rectal distension at a level of 100 mL or less was experienced in 21 subjects (14.2%). As defined by isobaric distensions, incontinent patients with low MTV had more frequently a hypocompliant rectum (62%) when compared with those with higher MTV (31%, P = 0.046). Perception scores tended to be higher at each step of distending rectal pressure: incontinent patients with low MTV had more frequently a hypersensitive rectum (48%) when compared with those with normal or high MTV (24%, P = 0.035). Only four of 21 incontinent subjects with low MTV had an isolated hypersensitive rectum.

Conclusion : Both sensitivity and compliance are altered in patients with low MTV. A more extensive study of the role of sensory and compliance aspects of subjects with incontinence is warranted.
Poor metabolizer genotype status of CYP2C19 is a risk factor for developing gastric cancer in Japanese patients with Helicobacter pylori infection
Authors: SUGIMOTO M. , FURUTA T. , SHIRAI N. , NAKAMURA A. , KAJIMURA M. , SUGIMURA H. , HISHIDA A. , ISHIZAKI T.
Published: October 2005

Background : Cytochrome P450 2C19 (CYP2C19) polymorphism has been associated with the development of lung, liver or oesophageal cancer by detoxification of carcinogen(s) or activation of procarcinogen(s).

Aim:  To clarify the association between CYP2C19 polymorphisms and gastric cancer development in Japanese.

Methods : We determined CYP2C19 genotypes (CYP2C19*1, *2 and *3) in 111 Helicobacter pylori‐positive patients with gastric cancer and 315 H. pylori‐positive controls without gastric cancer consisting of patients with gastritis only or peptic ulcer. Frequencies of CYP2C19 genotypes and serum pepsinogen I and II levels, a biomarker of gastric atrophy, in the gastric cancers and controls were compared.

Results : Frequencies of homozygous extensive metabolizers, heterozygous extensive metabolizers and poor metabolizers were 31.5%, 42.3% and 26.2% in the gastric cancers and 38.1%, 47.0% and 14.9% in the controls, respectively (P = 0.046). Poor metabolizers were associated with an increased risk for developing gastric cancer with the age‐ and sex‐adjusted odds ratio (OR) of 1.975 [95% confidence interval (CI): 1.068–3.649], especially for diffuse type (OR: 3.385, CI: 1.187–9.648). There is no significant association between CYP2C19 genotypes and serum pepsinogen I level or pepsinogen I/II ratios, although serum pepsinogen I level in gastric cancers were significantly decreased.

Conclusions : In H. pylori‐positive Japanese, poor metabolizers of CYP2C19 appear to be at an increased risk for developing gastric cancer, especially diffuse type, and may require an intensive follow‐up for scrutinizing possible gastric cancer development.
Efficacy of depot long‐acting release octreotide therapy in severe dumping syndrome
Authors: PENNING C. , VECHT J. , MASCLEE A. A. M.
Published: October 2005

Background:  Dumping syndrome is a serious complication occurring in 10% of patients after gastric surgery. Dumping symptoms are effectively reduced by subcutaneous application of the somatostatin analogue octreotide, but side‐effects limit its use.

Aim:  To evaluate the efficacy of depot long‐acting release octreotide (Sandostatin‐LAR) vs. octreotide subcutaneous on dumping symptoms, quality of life and side‐effects.

Methods:  Twelve patients (five females, age 58 ± 3 years) with severe dumping symptoms, requiring daily use of octreotide subcutaneous, were included in an open study and changed from octreotide subcutaneous after a 2 weeks washout to Sandostatin‐LAR 10 mg i.m., every 4 weeks for 6 months. Symptoms (diary), body weight, fat excretion, food intake and Gastrointestinal Specific Quality of Life Index were evaluated.

Results:  Gastrointestinal Specific Quality of Life Index increased significantly (P < 0.05) during Sandostatin‐LAR treatment (88 ± 4) compared with octreotide (74 ± 4) and washout (75 ± 6). During Sandostatin‐LAR treatment, abdominal symptom score was lower compared with octreotide and washout, but not significantly. During Sandostatin‐LAR treatment, body weight increased (66 ± 4 to 70 ± 3 kg; P = 0.19).

Conclusions:  Sandostatin‐LAR is at least as effective as octreotide subcutaneous in suppressing symptoms in patients with severe dumping syndrome and is more effective than octreotide subcutaneous in increasing body weight and quality of life.
Review article: the treatment of non‐alcoholic steatohepatitis with thiazolidinediones
Authors: REYNAERT H. , GEERTS A. , HENRION J.
Published: October 2005

It is generally accepted that non‐alcoholic fatty liver disease will be the most frequent liver disease in the near future and that the management of patients with non‐alcoholic fatty liver disease will be a challenge for hepatologists in the next decades.

Non‐alcoholic fatty liver disease is considered the hepatic manifestation of the metabolic syndrome, in which insulin resistance plays a crucial role. Although steatosis will often not progress to severe liver disease, in some patients, it results in cirrhosis and even hepatocellular carcinoma. Therefore, it is important to identify those patients at risk for developing fibrosis. Age, diabetes, obesity and hypertriglyceridaemia are independent risk factors for fibrosis in patients with elevated serum alanine aminotransferase levels and steatosis on ultrasound. The presence of multiple metabolic disorders increases the risk.

Apart from diet, exercise and correction of underlying metabolic abnormalities, no specific treatment is available at the moment. Theoretically, thiazolidinediones are an attractive way to treat non‐alcoholic fatty liver disease, because they improve insulin resistance. Some preliminary studies with thiazolidinediones were encouraging, as steatosis, inflammation and fibrosis improved in a substantial number of patients. Although no serious side effects occurred in the pilot studies, we should look vigilantly for hepatotoxicity, as the first generation thiazolidinediones proved to be toxic for the liver.
The expression of minichromosome maintenance protein‐2 in normal and abnormal megakaryocytes and comparison with the proliferative marker Ki‐67
Authors: Lampert Irvin A. , Horncastle Donna , Dilworth Steven , Roberts Irene , Alison Malcolm R. , Naresh Kikkeri N.
Published: October 2005

The minichromosome maintenance (Mcm) and Cdc6 proteins are important regulators of eucaryotic DNA replication. In most normal tissues, a similar proportion of cells express Mcm‐2 and Ki‐67. The present study showed that in both normal and abnormal states, the proportion of megakaryocytes expressing Mcm‐2 is roughly seven times as many as those that express Ki‐67. This is likely to be related to the process of endomitosis and endoreduplication. We also demonstrated that a significantly lower proportion of megakaryocytes in myelodysplastic syndrome express Mcm‐2. These findings provide new insights into megakaryocyte biology.
Lymphocyte subsets in irradiation‐induced sialadenitis of the submandibular gland
Authors: Teymoortash A , Simolka N , Schrader C , Tiemann M , Werner J A
Published: October 2005

Aims : Irradiation‐induced sialadenitis is a significant cause of morbidity in head and neck cancer patients receiving radiotherapy. Neither the exact aetiopathology of chronic irradiation‐induced sialadenitis nor the mechanisms leading to atrophy of the glandular cells associated with an increase in extracellular matrix are understood. The aim of our study was to determine the phenotype of the inflammatory infiltrate and to study its distribution in the affected submandibular glands.

Methods and results : Paraffin‐embedded submandibular glands from a homogeneous group of 19 patients with advanced oropharyngeal cancer who received conventional radiotherapy to the primary site and upper neck were analysed. In all patients the radiation dose and field were approximately equal. The submandibular glands were obtained during neck dissection. To characterize the lymphoid infiltrate, all tissue sections were immunostained for T cells (CD3, CD4, CD8), cytotoxic T cells (granzyme B), B cells (CD20), and macrophages (Ki‐M1p). A histopathological classification into four grades was established based on the degree of glandular atrophy, fibrosis and lymphocytic infiltration. Phenotypic analysis of submandibular gland sections revealed that the great majority of lymphocytic infiltrates were cytotoxic T cells associated with acinar cell destruction.

Conclusions : The significantly elevated frequencies of cytotoxic cells in the submandibular glands of patients with irradiation‐induced sialadenitis suggest that cell‐mediated immune mechanisms may play a part in the pathogenesis of this disease.
Galanin‐Like Peptide Promotes Feeding Behaviour Via Activation of Orexinergic Neurones in the Rat Lateral Hypothalamus
Authors: Kageyama H. , Kita T. , Toshinai K. , Guan J.‐L. , Date Y. , Takenoya F. , Kato S. , Matsumoto H. , Ohtaki T. , Nakazato M. , Shioda S.
Published: October 2005

Galanin‐like peptide (GALP) is produced in neurones in the hypothalamic arcuate nucleus and is implicated in the neural control of feeding behaviour. Previously, we have reported that GALP immunoreactive fibres were in direct contact with orexin/hypocretin immunoreactive neurones in the rat lateral hypothalamus using double‐immunofluorescence. Centrally administered GALP is known to stimulate feeding behaviour. However, the target neurones of this action have not been clarified. The present study aimed to determine features of the GALP‐mediated neuronal feeding pathway in rat. Accordingly, at the ultrastructural level, GALP‐immunoreactive axon terminals were found to make synapses on orexin/hypocretin immunoreactive cell bodies and dendritic processes in the lateral hypothalamus. c‐Fos immunoreactivity was expressed in orexin/hypocretin‐immunoreactive neurones but not in melanin concentrating hormone‐immunoreactive neurones in the lateral hypothalamus at 90 min after the application of GALP by i.c.v. infusion. Furthermore, to determine whether GALP regulates feeding behaviour via orexin/hypocretin neurones, the feeding behaviour of rats was studied following GALP i.c.v. injection with or without anti‐orexin A and B immunoglobulin (IgG) pretreatment. The anti‐orexin IgGs markedly inhibited GALP‐induced hyperphagia. These results suggest that orexin/hypocretin‐containing neurones in the lateral hypothalamus are targeted by GALP, and that GALP‐induced hyperphagia is mediated via orexin/hypocretin neurones in the rat hypothalamus.
Coordinated activation of metabolic pathways for antioxidants and defence compounds by jasmonates and their roles in stress tolerance in Arabidopsis
Authors: Sasaki‐Sekimoto Yuko , Taki Nozomi , Obayashi Takeshi , Aono Mitsuko , Matsumoto Fuminori , Sakurai Nozomu , Suzuki Hideyuki , Hirai Masami Yokota , Noji Masaaki , Saito Kazuki , Masuda Tatsuru , Takamiya Ken‐ichiro , Shibata Daisuke , Ohta Hiroyuki
Published: October 2005

Jasmonic acid (JA) and methyl jasmonate (MeJA), collectively termed jasmonates, are ubiquitous plant signalling compounds. Several types of stress conditions, such as wounding and pathogen infection, cause endogenous JA accumulation and the expression of jasmonate‐responsive genes. Although jasmonates are important signalling components for the stress response in plants, the mechanism by which jasmonate signalling contributes to stress tolerance has not been clearly defined. A comprehensive analysis of jasmonate‐regulated metabolic pathways in Arabidopsis was performed using cDNA macroarrays containing 13516 expressed sequence tags (ESTs) covering 8384 loci. The results showed that jasmonates activate the coordinated gene expression of factors involved in nine metabolic pathways belonging to two functionally related groups: (i) ascorbate and glutathione metabolic pathways, which are important in defence responses to oxidative stress, and (ii) biosynthesis of indole glucosinolate, which is a defence compound occurring in the Brassicaceae family. We confirmed that JA induces the accumulation of ascorbate, glutathione and cysteine and increases the activity of dehydroascorbate reductase, an enzyme in the ascorbate recycling pathway. These antioxidant metabolic pathways are known to be activated under oxidative stress conditions. Ozone (O3) exposure, a representative oxidative stress, is known to cause activation of antioxidant metabolism. We showed that O3 exposure caused the induction of several genes involved in antioxidant metabolism in the wild type. However, in jasmonate‐deficient Arabidopsis 12‐oxophytodienoate reductase 3 (opr3) mutants, the induction of antioxidant genes was abolished. Compared with the wild type, opr3 mutants were more sensitive to O3 exposure. These results suggest that the coordinated activation of the metabolic pathways mediated by jasmonates provides resistance to environmental stresses.
Genetic analysis of Arabidopsis GATA transcription factor gene family reveals a nitrate‐inducible member important for chlorophyll synthesis and glucose sensitivity
Authors: Bi Yong‐Mei , Zhang Yu , Signorelli Tara , Zhao Rong , Zhu Tong , Rothstein Steven
Published: October 2005

The Arabidopsis GATA transcription factor family has 30 members, the biological function of most of which is poorly understood. Homozygous T‐DNA insertion lines for 23 of the 30 members were identified and analyzed. Genetic screening of the insertion lines in defined growth conditions revealed one line with an altered phenotype, while the other lines showed no obvious change. This line, SALK_001778, has a T‐DNA insertion in the second exon of At5g56860 which prevents the expression of the GATA domain. Genetic analysis of the mutant demonstrated that the phenotypic change is caused by a single gene effect and is recessive to the wild‐type allele. In wild‐type plants, the expression of At5g56860 is shoot‐specific, occurs at an early stage of development and is inducible by nitrate. Loss of expression of At5g56860 in the loss‐of‐function mutant plants resulted in reduced chlorophyll levels. A transcript profiling experiment revealed that a considerable proportion of genes downregulated in the loss‐of‐function mutants are involved in carbon metabolism and At5g56860 is thus designated GNC (GATA, nitrate‐inducible, carbon metabolism‐involved). gnc mutants with no GNC expression are more sensitive to exogenous glucose, and two hexose transporter genes, with a possible connection to glucose signaling, are significantly downregulated, while GNC over‐expressing transgenic plants upregulate their expression and are less sensitive to exogenous glucose. These observations suggest a function for GNC in regulating carbon and nitrogen metabolism.
Growth‐chart‐based qualitative evaluation of height growth after hematopoietic stem cell transplantation
Authors: Narumi Satoshi , Shimada Hiroyuki , Shimasaki Noriko , Takahashi Takao , Hasegawa Tomonobu , Mori Tetsuya
Published: October 2005

Abstract:  Growth failure is one of the most common late complications in children undergoing hematopoietic stem cell transplantation (SCT). The present report describes a qualitative method of evaluating height growth after SCT, using a growth chart. The patients were divided into three groups according to the shape of their growth chart: the normal growth chart group, the early‐onset growth retardation group (E‐group), in which a decreased growth rate was seen during the first year after SCT, and the late‐onset growth retardation group (L‐group), in which a decreased growth rate was seen more than 1 yr after the SCT. In the E‐group, total body irradiation and prolonged steroid therapy were thought to contribute to the growth failure, whereas in the L‐group, impaired pubertal development was thought to be responsible. The growth pattern in the L‐group may, therefore, be of particular clinical importance, because the final stature of the subjects in this group can be improved by pharmacological adjustment of pubertal onset. Although limited by the small size and heterogeneous nature of the sample, our results suggest that growth‐chart‐based evaluation may provide important information to stratify subjects showing inadequate growth after SCT into two groups whose follow‐up and treatment should be individualized.
Successful long‐term outcome of kidney transplantation in a child with Kabuki syndrome
Authors: Hamdi Kamel M. , Gilmartin B. , Mohan P. , Hickey D. P.
Published: October 2005

Abstract:  We report a case of successful renal transplantation in a child with Kabuki syndrome. We discuss the potential problems that might be encountered following kidney transplantation in children with Kabuki syndrome, and the management of these problems. We conclude that kidney transplantation is a feasible and appropriate treatment option for renal impairment in children with this syndrome.
Severe peripheral pulmonary artery stenosis is not a contraindication to liver transplantation in Alagille syndrome
Authors: Özçay Figen , Varan Birgül , Tokel Kürşad , Çetin İlker , Dalgiç Aydın , Haberal Mehmet
Published: October 2005

Abstract:  We described a case of Alagille syndrome with severe peripheral pulmonary artery stenosis and very high right ventricular pressure that underwent successful living‐related liver transplantation without any peri‐operative and mid‐term postoperative complication because of this cardiac malformation. The aim of this report is to point out that the severe pulmonary artery stenosis may be a risk factor but not a contraindication to liver transplantation in patients with Alagille syndrome.
Intermediate‐dose cidofovir without probenecid in the treatment of BK virus allograft nephropathy
Authors: Araya Carlos E. , Lew Judy F. , III Fennell Robert S. , Neiberger Richard E. , Dharnidharka Vikas R.
Published: October 2005

Abstract:  BK virus allograft nephropathy (BKVAN) is a rising complication in kidney transplant recipients. Reducing immunosuppression has been the initial form of therapy in most cases, but is not always associated with improvement in graft function. Anti‐viral therapy with low‐dose cidofovir (0.25–0.42 mg/kg/dose) has been used successfully in some patients, but dose‐related nephrotoxicity has limited its use. We present our experience with 3 kidney transplant recipients diagnosed with BKVAN who received intermediate‐dose cidofovir (0.75–1.0 mg/kg/dose) without probenecid, and without concomitant nephrotoxicity. Three female patients, ages 8, 19 and 20 yr, presented with elevated serum creatinine (SCr) values, BK virus stain positive on renal biopsy and high plasma BK viral loads. As a result of viral loads being >2 million copies/ml in two patients and a lack of response to reduction in immunosuppression in the third, we initiated therapy with low‐dose cidofovir. Because of persistent positive BK stain and positive plasma viral load, we then administered intermediate‐dose cidofovir, without probenecid, for several subsequent doses (seven to 15 infusions till date). All patients tolerated the intermediate‐dose cidofovir with no significant rise in SCr during the course of the infusions. The most recent SCr values in all three patients were improved from those at the initial diagnosis of BKVAN. All three patients showed a marked drop in BK viral loads when on intermediate‐dose cidofovir, with complete clearing of viremia in two patients. In our experience, intermediate‐dose cidofovir without probenecid, used judiciously, is not associated with additional nephrotoxicity and may provide an additional alternative for treatment.
An alternative method of arterial reconstruction in pediatric living donor liver transplantation with the recipient right gastroepiploic artery
Authors: Tannuri Uenis , Maksoud‐Filho João G. , Silva Marcos M. , Suzuki Lisa , Santos Maria M. , Gibelli Nelson E. , Ayoub Ali A. , Velhote Manoel C. P. , Pinho‐Apezzato Maria L. , Maksoud João G.
Published: October 2005

Abstract: The classical method for arterial reconstruction in pediatric living donor liver transplantation using left lateral segment consists of end‐to‐end anastomosis between the donor left hepatic artery and the recipient right hepatic artery. In the present case, an intra‐operative hepatic artery thrombosis occurred because of extensive intima wall dissection of the recipient hepatic artery. The patient was a 6‐yr‐old boy with fulminant hepatic failure, who underwent living donor partial liver transplantation with left lateral segment from his father. The graft was irrigated by a left hepatic artery and an accessory left hepatic artery from gastric artery, both arteries with diameter of <2 mm. These arteries were anastomosed to the recipient right and left hepatic arteries, respectively. Before performing the bile duct reconstruction it was noted that these anastomoses were occluded by clots of blood. An extensive subintimal dissection of the recipient hepatic artery was the cause of this problem. The creation of a new anastomosis by using a more proximal part of this artery without subintimal dissection was judged impossible. Then, the right gastroepiploic artery was mobilized and an anastomosis was performed with the donor left hepatic artery in an end‐to‐end fashion. Arterial blood flow to the graft was established successfully and the patient's postoperative recovery was excellent. Fifteen days after the transplantation, an angiotomography demonstrated a good hepatic arterial blood flow. The patient is now alive and well, 4 months after the transplantation. In conclusion, the method of hepatic graft arterialization described here is an important option for patients who undergo living donor or split liver transplantation.
Successful renal transplantation in a patient with heterozygous prothrombin gene, factor V Leiden mutation and heparin‐induced thrombocytopenia using r‐hirudin as anticoagulant
Authors: John Ulrike , Kentouche Karim , Nowak Goetz , Schubert Jörg , Misselwitz Joachim
Published: October 2005

Abstract:  Vascular complications remain the most common cause of early renal allograft loss in patients with end‐stage renal failure. Underlying thrombophilic disorders increase the risk of early graft thrombosis. A male adolescent with high‐risk thrombophilia because of combined heterozygous factor V Leiden (G1691A) and prothrombin gene (G20210A) mutation developed HIT II. Hemodialysis and subsequent renal transplantation were undertaken using recombinant hirudin, a direct and selective thrombin inhibitor, as an anticoagulant. Primary function in the transplanted kidney was excellent. No thrombotic or hemorrhagic events have occurred and follow‐up showed excellent long‐term graft survival. Patients on HD have an increased risk for the development of HIT, and therefore, they need repetitive screening for the development of acquired thrombotic risk factors (e.g. HIT II or lupus anticoagulant). R‐hirudin is efficacious and safe on both HD and following renal transplantation.
Post‐transplant lymphoproliferative disorder following pediatric heart transplantation
Authors: Mendoza Fernando , Kunitake Hiroko , Laks Hillel , Odim Jonah
Published: October 2005

Abstract:  Immunosuppression after heart transplantation is implicated in development of post‐transplant lymphoproliferative disorder (PTLD). Despite a higher prevalence of PTLD in children, there is scarce knowledge about incidence, pathophysiologic mechanisms and risk factors for PTLD in pediatric recipients of cardiac allografts. We examined retrospectively the medical records of all 143 pediatric patients (mean age 9.2 ± 6.1 yr) who received donor allografts between 1984 and 2002 and survived over 30 days. Five children (3.5%) developed PTLD over a mean follow‐up period of 41.1 ± 46.0 months. Time from transplant to diagnosis of PTLD ranged from 3.9 to 112 months (mean 48.0 ± 41.9 months). Excluding PTLD, no other malignancies were found in this population. Actuarial freedom from PTLD was 99.2%, 99.2% and 96.2% at 1, 2, and 5 yr, respectively. Children who developed PTLD were more likely (by univariate analysis) to have been Rh negative (p = 0.01), Rh mismatched (p = 0.003), Epstein–Barr virus (EBV) seronegative (p = 0.001) and transplanted for congenital heart disease (p < 0.02). PTLD was associated with significant morbidity and mortality with a mean survival following diagnosis of 21.2 months. PTLD is a serious complicating outcome of cardiac transplantation that occurs in approximately 3.5% of children. Aside of immunosuppression, risk factors in this series for developing PTLD include EBV seronegativity and Rh negative status and mismatch. Non‐hematogenous malignancies are rare in light of short allograft half‐life.
Buccal vs. nasogastric tube administration of tacrolimus after pediatric liver transplantation
Authors: Goorhuis Joanne F. , Scheenstra Rene , Peeters Paul M. J. G. , Albers Marcel J. I. J.
Published: October 2005

Abstract:  Tacrolimus is an important drug for immunosuppression after liver transplantation. Bioavailability of enterally administered tacrolimus is poor, and further reduced by gastric residuals or by enteral nutrition. Buccal administration might be an alternative route especially in children. Tacrolimus trough levels (TTLs) obtained after buccal administration of tacrolimus after liver transplantation have not been reported. The aim of this study was to determine whether buccal administration of tacrolimus is feasible and to compare TTLs after nasogastric tube (NGT) administration with buccal administration. TTLs after NGT or buccal administration during the first week after pediatric liver transplantation were analyzed from 28 cadaveric liver transplants in 23 pediatric recipients between June 2002 and March 2004. Each level was scored within, under or above the target range. Buccal administration was well tolerated in all patients. A total of 149 TTLs were obtained of which nine were excluded because of incomplete information on target levels. Overall 27% of TTLs was adequate. The percentage of levels under, within and above the target range were comparable in both groups (chi‐square test; p = 0.64). Both groups had a decrease in percentages within the target range on day 3 and 4 after liver transplantation with a subsequent rise. Buccal tacrolimus administration is feasible. Similar TTLs are achieved compared with NGT tacrolimus administration during the first week after pediatric liver transplantation.