bluuebunny/crossref_metadata_2025 huggingface dataset:
Electric field gradients in cuprates: Does LDA+U give the correct charge distribution?
Authors: Blaha P. , Schwarz K. , Novák P.
Published: October 2004

We present calculations for the electric field gradients (EFG) on the Cu sites in La2CuO4, YBa2Cu3O6, and YBa2Cu3O7 using standard LDA and GGA exchange‐correlation functionals, but also by using the LDA+U method for the correlated Cu‐d electrons. LDA or GGA calculations yield proper EFGs in agreement with experiment for all sites except the planar Cu(2) site, where the theoretical EFGs are too small by a factor of 2 to 3. This happens for both the metallic (superconducting) YBa2Cu3O7 and the antiferromagnetic insulators. For the latter, these calculations also lead to a nonmagnetic and metallic solution. Application of LDA+U with various double‐counting corrections and varying values for the Hubbard parameter U gives the correct magnetic and insulating ground state and the corresponding EFGs are substantially enhanced. Best agreement with experiment is found using the LDA+U(FLL) method with U around 6 eV, because this method leaves the Cu(1) EFG unchanged, even when U is applied to its d‐states. For the metallic compound YBa2Cu3O7, the EFG results favor the presence of local magnetic moments; however, in bandstructure calculations the necessary long‐range order leads to some artifacts and should be replaced by random spin fluctuations. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Soft cohesive forces
Authors: Dobson John F. , Wang Jun , Dinte Bradley P. , McLennan Keith , Le Hung M.
Published: October 2004

We discuss dispersion forces, beginning with toy models that illustrate the limitations of various standard approaches. For metallic cohesion of very thin layers, we show that because the local density approximation (LDA) misses distant dispersion interactions, it also makes significant errors in the maximum cohesive force, a short‐ranged property. Furthermore, perturbative methods fail for such large planar systems, and CI methods are impractical. For large planar and linear systems in the well‐separated limit we show that insulating and metallic systems can exhibit very different dispersion forces, pairwise summation of atomic R−6 terms failing for the metallic cases. This could have implications for the interaction between nanotubes and between graphene planes: these planes are zero‐gap insulators at large separation and weak metals at graphitic equilibrium. Graphitic cohesion and intercalation are fundamental to a hydrogen economy and to various nanotechnologies, yet our arguments strongly suggest that all standard methods are inadequate for these phenomena. We argue that nonlocal RPA‐like correlation energy formulae contain all the required “seamless” physics of long‐ and short‐ranged interaction, as needed for graphitic and other soft‐matter systems. Indeed full calculations of this type are currently being attempted for graphite, and appear to be very delicate. We discuss recent efforts to approximate these calculations, and propose a new scheme. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
DFT calculations of light‐induced excited states and comparison with time‐resolved crystallographic results
Authors: Coppens Philip , Novozhilova Irina V.
Published: October 2004

DFT calculations of the ground and first excited states of several transition metal complexes have been performed to complement time‐resolved diffraction experiments. The results from different functionals and relativistic treatments are tested against both diffraction and spectroscopic values. Calculations of the d8–d8complex [Pt2(pyrophosphite)4]4−quantitatively reproduce metal–metal shortening on excitation to the triplet state and support bond formation between the two metal centers, as do calculations on [Rh2(1,3‐diisocyanopropane)4]2+. Results on homoleptic and heteroleptic copper(I) 2,9‐dimethyl−1,10‐phenanthroline (dmp) complexes, which are investigated because of their potential for solar energy capture, confirm considerable molecular deformations on excitation. The distortion calculated for the isolated complex [Cu(dmp)(dmpe)]+(dmpe=1,2‐bis(dimethylphosphino)ethane) is significantly larger than observed in the crystal, indicating the constraining effect of the crystalline environment. The change in the net charge of the Cu atom upon photo‐induced metal‐to‐ligand charge transfer is less than 0.2 e, showing the limitations of the formal Cu(I)→Cu(II) designation. Electron density difference maps show a pronounced change in electronic structure of the Cu atom on excitation. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Estimation of physiologically perceived color from TDDFT‐derived excitation spectra
Authors: Beck M. E.
Published: October 2004

A new scheme for estimating the physiologically perceived color of a compound from its chemical structure is presented. The first step of this schema was the calculation of electronic excitation energies and probabilities. In this contribution, time‐dependent Density Functional Theory (TDDFT) was used for this purpose. From the excitation energies and oscillator strengths, line shape was approximated by folding with Gaussian functions. Using this spectrum, the CIE1931 chromaticity coordinates were gained by numerical integration. The dependence of the chromaticity coordinates on the band width of the Gaussians was visualized in a chromaticity diagram. From this diagram, the color, as physiologically perceived by a human observer, was estimated. The approach was applied to nine textbook examples of dyes and its limitations are discussed critically. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Density functional theory calculations on microscopic aspects of oxygen diffusion in ceria‐based materials
Authors: Frayret Christine , Villesuzanne Antoine , Pouchard Michel , Matar Samir
Published: October 2004

The critical role of the ionic conductivity properties of materials in the development of Intermediate Temperature Solid Oxide Fuel Cell (IT‐SOFC) technology has been emphasized over the past decade. However, from a fundamental point of view, little is known of the physicochemical parameters influencing ionic diffusion in these conductors. We attempted, through a Density Functional Theory investigation, to develop a new approach for an oxygen diffusion study in solids at the atomic scale. This methodology relies on the evaluation and comparison of steric, energetic, and chemical bonding factors along with the consideration of charge transfers when mixed valences do exist. Microscopic aspects of oxygen diffusion in the ionic conductor ceria‐based materials have been investigated by means of this procedure. It has been demonstrated that steric and polarizability effects prevail over other ones for both nonstoichiometric and doped ceria. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Simulation of UV/visible absorption spectra of (α‐diimine)nickel(II) catalysts by time‐dependent density functional theory
Authors: Cavillot Valérie , Champagne Benoît
Published: October 2004

The metal‐to‐ligand charge‐transfer excited states of (α‐diimine)‐NiII catalysts were simulated using time‐dependent density functional schemes for three reaction intermediates: the active site with a methyl group to mimic the growing alkyl chain, the corresponding π‐complex formed with an ethylene molecule, and the product where the propyl chain displays a γ‐agostic interaction. The simulations provide a basis for analyzing the experimental data in terms of charge‐transfer and enable one to assess the variations of the spectra upon modifications of the bidentate ligand. Moreover, the impact of the atomic basis set and exchange‐correlation functionals on the electronic absorption spectra was addressed in view of a more systematic use on new late transition metal catalysts. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Density functional theory study on the thermodynamic properties of aminophenols
Authors: Gomes José R. B. , Da Silva Manuel A. V. Ribeiro
Published: October 2004

Density Functional Theory was used to investigate several gas‐phase thermodynamic parameters of the o‐, m‐, and p‐aminophenol isomers. Within the DFT approach, the B3LYP method and the 6‐31G(d) and 6‐311+G(2d,2p) basis sets were used to compute standard enthalpies of formation. Calculated data are in excellent agreement with the experimental work of Nuñez et al. [J Chem Thermodyn 1996, 18, 575–579] but differs significantly from the values of Sabbah et al. [Can J Chem 1996, 74, 500–507]. In this work, other properties such as homolytic O‐H and N‐H bond dissociation energies, gas‐phase acidities, and proton or electron affinities were also obtained and confirm the few experimental results available for these properties in these kind of compounds, except the O‐H homolytic dissociation energy of 2‐aminophenol. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Energy analysis of the chemical bond in group IV and V complexes: A density functional theory study
Authors: Poleshchuk O. Kh. , Shevchenko E. L. , Branchadell V. , Lein M. , Frenking G.
Published: October 2004

We analyzed the chemical bond between antimony, tin, titanium, and niobium chlorides with several Lewis bases using an energy partitioning analysis (EPA) and Weinhold's NBO method. The optimized geometries are in good agreement with the experimental results. The NQR‐35Cl frequencies appear to be fairly close to the experimental values. Theoretically obtained nuclear quadrupole coupling constants of antimony and niobium atoms are in good agreement with the experimental values. The bonding energies and experimentally known heats of formation are well reproduced by the employed level of theory. All investigated bonds in the donor‐acceptor complexes are highly polar, so that the Townes‐Dailey theory cannot be applied. The NBO approach shows that the donor–acceptor interactions of main‐group elements such as Sb and Sn can basically be described in terms of sp hybridization, just as these interactions of the transition metal elements Ti and Nb can be described by sd hybridization. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Structure by theory and experiment: One nationality, two languages
Authors: Hinchley Sarah L. , Wann Derek A. , Rankin David W. H.
Published: October 2004

The determination of structure in the gas phase is an important technique for obtaining accurate structural information for molecules, free from intermolecular interactions that could affect solid‐state structures. For large asymmetric molecules, obtaining the full gas‐phase structure using experimental data alone is virtually impossible in most cases. The utilisation of theoretical methods in the determination of the experimental molecular structure has allowed many more molecules to be studied, revealing important structural information. This information can be used by theoreticians to develop their methods further, and so both experimentalists and theoreticians benefit. This article describes the development of these methods and uses some examples to demonstrate their importance. These include the determination of the gaseous molecular structures of ferrocene and isopropylferrocene, and of the bis[bis(trimethylsilyl)methyl]phoshido radical, for which Density Functional Theory is realistically the only theoretical method available to aid the determination of the gas‐phase structure. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Metyrapone attenuates the sequential learning deficits but not monoamine depletions following d,l‐fenfluramine administration to adult rats
Authors: Skelton Matthew R. , Blankenmeyer Tracy L. , Gudelsky Gary A. , Brown‐Strittholt Carrie A. , Vorhees Charles V. , Williams Michael T.
Published: October 2004

Fenfluramine (FEN) is a substituted amphetamine known for its anorectic effects, without the stimulatory or abuse potential associated with other amphetamine derivatives. FEN is a potent serotonin (5‐HT) releaser and reuptake inhibitor and has been shown to cause depletions of 5‐HT that can last days and even weeks after administration. Administration of FEN four times on a single day also causes a prolonged increase of corticosterone (CORT) that lasts ∼72 h following the first FEN dose. This dosing regimen also produces deficits in sequential learning as measured in the Cincinnati water maze (CWM). Adrenalectomy blocks this effect but removes more than CORT. Accordingly, the purpose of this study was to determine whether inhibiting glucocorticoid production, by administration of the 11β‐hydroxylase inhibitor metyrapone (MET), will similarly attenuate or eliminate the sequential learning deficits seen with FEN exposure. MET (50 mg/kg) injections were administered 90 min prior to and for 3 days after FEN (four doses given at 2‐h intervals). Animals pretreated with MET and treated with FEN showed no sequential learning deficits when tested 1 week following FEN administration compared to FEN alone. The depletions of monoamines were similar following FEN administration, regardless of MET treatment. Taken together, this suggests that a potential mechanism for the sequential learning deficits in FEN‐treated animals is a result of prolonged increases in CORT output. Synapse 54:214–222, 2004. © 2004 Wiley‐Liss, Inc.
Characterization of a gene similar to BIK1 in the yeast Kluyveromyces lactis
Authors: Lamas‐Maceiras M. , Cerdán M. E. , Lloret A. , Freire‐Picos M. A.
Published: October 2004

In Saccharomyces cerevisiae, Bik1p is a microtubule plus‐end‐tracking protein that plays several roles in mitosis and ploidy. KlBik1p (from Kluyveromyces lactis) maintains the same structural‐domain organization as does S. cerevisiae Bik1p. As part of its characterization, we constructed a stable klbik1 mutant which is sensitive to benomyl only at 14 °C and has a higher frequency of crescent‐shaped nuclei than S. cerevisiae bik1 mutants. This phenotype is partially rescued by S. cerevisiae BIK1. Other phenotypes associated with bik1 are not present in the K. lactis mutant. By fusion to GFP we were able to show the functionality of the KlBik1p CAP–Gly domain and found that the fusion protein changes its cellular location during the cell cycle. Copyright © 2004 John Wiley & Sons, Ltd.
The cell wall sensor Wsc1p is involved in reorganization of actin cytoskeleton in response to hypo‐osmotic shock in Saccharomyces cerevisiae
Authors: Gualtieri Tania , Ragni Enrico , Mizzi Luca , Fascio Umberto , Popolo Laura
Published: October 2004

The cell wall is essential to preserve osmotic integrity of yeast cells. Some phenotypic traits of cell wall mutants suggest that, as a result of a weakening of the cell wall, hypo‐osmotic stress‐like conditions are created. Consequent expansion of the cell wall and stretching of the plasma membrane trigger a complex response to prevent cell lysis. In this work we examined two conditions that generate a cell wall and membrane stress: one is represented by the cell wall mutant gas1Δ and the other by a hypo‐osmotic shock. We examined the actin cytoskeleton and the role of the cell wall sensors Wsc1p and Mid2p in these stress conditions. In the gas1 null mutant cells, which lack a β(1,3)‐glucanosyltransferase activity required for cell wall assembly, a constitutive marked depolarization of actin cytoskeleton was found. In a hypo‐osmotic shock wild‐type cells showed a transient depolarization of actin cytoskeleton. The percentage of depolarized cells was maximal at 30 min after the shift and then progressively decreased until cells reached a new steady‐state condition. The maximal response was proportional to the magnitude of the difference in the external osmolarity before and after the shift within a given range of osmolarities. Loss of Wsc1p specifically delayed the repolarization of the actin cytoskeleton, whereas Wsc1p and Mid2p were essential for the maintenance of cell integrity in gas1Δ cells. The control of actin cytoskeleton is an important element in the context of the compensatory response to cell wall weakening. Wsc1p appears to be an important regulator of the actin network rearrangements in conditions of cell wall expansion and membrane stretching. Copyright © 2004 John Wiley & Sons, Ltd.
An in vitro assay for (1 → 6)‐β‐D‐glucan synthesis in Saccharomyces cerevisiae
Authors: Vink Edwin , Rodriguez‐Suarez Roberto J. , Gérard‐Vincent Manon , Ribas Juan Carlos , de Nobel Hans , van den Ende Herman , Durán Angel , Klis Frans M. , Bussey Howard
Published: October 2004

(1 → 6)‐β‐D‐glucan is a key cell wall component of Saccharomyces cerevisiae and Candida albicans. Many genes are known to affect the levels or structure of this glucan, but their roles and a molecular description of the synthesis of (1 → 6)‐β‐D‐glucan remain to be established and a method to measure (1 → 6)‐β‐D‐glucan synthase activity in vitro would provide an enabling tool. Here, conditions for the detection of in vitro synthesis of this polymer are described. Crude membrane preparations from S. cerevisiae were isolated, and incubated in the presence of UDP‐glucose and GTP. With anti‐(1 → 6)‐β‐D‐glucan‐specific antibodies, a time‐dependent increase in the amount of this glucan was demonstrated in a dot–blot assay, or through an inhibition enzyme immunoassay. Antibody specificity was validated by competition experiments using pustulan, a (1 → 6)‐β‐D‐glucan, laminarin, a (1 → 3)‐β‐D‐glucan, yeast mannan and glycogen. The identity of the reaction product was also demonstrated by its sensitivity to a recombinant (1 → 6)‐β‐D‐glucanase. Extracts from mutants in 10 genes with a wide range of altered cell wall (1 → 6)‐β‐D‐glucan levels were assayed for in vitro synthesis of the polymer. A strong correlation of in vitro synthase activity with in vivo glucan levels was found, providing genetic support for the specificity of the assay. The basis for the GTP‐dependence of the synthase reaction was studied. Extracts from rho2, rho3, rho4 and rho5 null mutants had wild‐type in vitro activity. In contrast, Rho1p overproduction led to increased in vitro synthesis, implicating Rho1p in the regulation of (1 → 6)‐β‐D‐glucan synthesis. Copyright © 2004 John Wiley & Sons, Ltd.
Staging of squamous esophageal cancer: Accuracy and value
Authors: Hölscher Arnulf H. , Dittler Hans Joachim , Siewert J. Rüdiger
Published: October 2004

Endoscopic ultrasonography (EUS) and computed tomography (CT) should be used as complementary methods for TNM staging of esophageal cancer. EUS is the most accurate modality for staging primary tumor and mediastinal lymph node metastases. CT should be used to detect infiltration of other mediastinal organs and distant metastases. For esophageal cancer staging magnetic resonance imaging (MRI) is not superior to CT. For detection of cervical lymph node metastases percutaneous ultrasonography is appropriate. In patients with advanced distal carcinoma of the esophagus, hepatic and peritoneal metastases and intraabdominal lymph node infiltration should be ruled out by laparos‐copy prior to surgery. The results of preoperative staging are relevant if the management of esophageal cancer comprises not only surgery but also endoscopic mucosectomy, primary palliative procedures, and especially neoadjuvant radiochemotherapy. Within therapeutic trials the precise staging prior to treatment is essential for analysis of the results. The value of routine postoperative staging during a follow‐up program is yet unproved for esophageal cancer.
Esophageal cancer, early disease: Diagnosis and current treatment
Authors: Becker Horst Dieter
Published: October 2004

Most esophageal cancers are at a fairly advanced stage at the time of diagnosis, and curative therapy is not possible. For those that are detected early, cure may be possible, particularly if there is no lymphatic spread. Radical therapeutic approaches result in increased treatmentrelated mortality, high treatment‐induced morbidity, and reduced quality of life. Therefore it is one of the major targets in the treatment of esophageal cancers to classify the tumor and to perform adequate stage‐related therapy. The modern diagnositic procedures, such as endoscopy, endoluminal sonography, computed tomography (CT) scanning, and endoscopic biopsy, have led to major advances in preoperative staging. Endoluminal sonography is able to predict the depth of tumor infiltration in the esophageal wall and the existence of local lymph node metastasis, whereas CT scanning demonstrates distant metastasis. Histologic classification of the tumor together with genetic and cell biologic characteristics can predict the prognosis. Currently, the best prospect for cure of early esophageal cancer is surgical resection through the abdominothoracic approach, although less radical surgical procedures such as transhiatal resection without extensive lymph node dissection seem to achieve the same results. Even less traumatic is the use of minimal invasive techniques, which certainly will be used more often in the future. For early esophageal cancers limited to the epithelium and the lamina propria, local destruction of the tumor leads to long‐term survival and cure. Techniques such as endoscopic resection, laser coagulation, photodynamic laser activation and argon beam exposure have been described and seem to achieve similar results. Another conservative method for treating early esophageal tumors is radiotherapy, although it has been shown in several studies that radiochemotherapy is superior to radiotherapy alone, at least in more advanced cases. In future, treating local early esophageal tumors will consist in exact preoperative staging followed by a surgical therapy that includes local excision of tumors limited to epithelium or a more aggressive approach if advanced infiltration of the esophageal wall has been proved. In these cases combined radiochemotherapy plus surgery is promising. In cases with increased operative risk the combination of local tumor destruction plus radiocheotherapy may improve the results.
Operable squamous esophageal cancer: Current results from the East
Authors: Zhang Da Wei , Cheng Gui Yu , Huang Guo Jun , Zhang Ru Gang , Liu Xiang Yang , Mao Yu Sun , Wang Yong Gang , Chen Sin Jie , Zhang Liang Ze , Wang Liang Jun , De Zhang Cao , Yang Lin , Meng Pin Jun , Sun Ke Lin
Published: October 2004

From 1958 through 1992 a total of 3603 patients underwent surgery for esophageal squamous cell carcinoma in our department. Among these patients 3099 resections were performed, for an overall resectability of 86.0%. Of the resections, 2341 (75.5%) were classified as curative and 758 (24.5%) palliative. The overall morbidity and 30‐day mortality rates were 23.4% and 3.8%, respectively. For resected cases the mortality was 4.0%. The more than 5‐year follow‐up rate of patients with resection was 97%. The actual 5‐, 10‐, and 15‐year survival rates were 30.4%, 23.6%, and 17.9%, respectively. Recurrence or metastasis remained the cause of death in 60.9% and 25.5% of patients who lived longer than 5 years and 15 years, respectively, after operation. The TNM staging, lymph node metastasis, extraesophageal invasion, tumor differentiation, tumor length, and category of operation were major determinants influencing long‐term prognosis. The left thoracotomy approach was used exclusively in 2613 cases (84.3% of all resected cases) in which intrathoracic resections and anastomoses were performed. The stomach was used as a substitute for the esophagus in 98.8% of the resected cases compared with 1.2% colon transplants. The former procedure was far safer than the latter. Above‐average results presented in this paper support the surgical policy we have pursued thus far: to resect the primary tumor by partial or subtotal esophagectomy and to remove all lymph nodes wherever they were found in all patients with disease earlier than stage III. Early detection and early treatment no doubt are the only ways to materially improve the long‐term surgical results.
Operable esophageal cancer: Current results from the West
Authors: Watson Anthony
Published: October 2004

Results are presented from a consecutive series of 396 patients referred to hospital in one of the areas of highest incidence in the United Kingdom in a unit that saw all referred cases for assessment and subsequent decision on the most appropriate therapeutic modality. Standard criteria were applied when selecting those patients in whom an attempt at curative resection was justified. Of the 396 patients, only 164 (41%) were considered fit enough to undergo thoracoabdominal resection and to have a tumor that had not invaded contiguous structures or metastasized. The remainder were treated by palliative intubation and more recently by laser photocoagulation. Of the patients who underwent resection, most had an Ivor Lewis esophagogastrectomy and lymphadenectomy, those with proximal lesions undergoing three‐stage total esophagectomy. The overall 30‐day mortality was 8.3%, falling to 6.7% during the period 1985–1990 when thoracic epidural analgesia was used routinely and fatal respiratory complications were avoided. Overall 5‐year survival rate was 23%. However, stratification for tumor staging showed that the 5‐year survival for node‐negative patients was 47% and for tumors confined within the adventitia 71%. Results of surgical treatment of squamous esophageal carcinoma in the West are considerably more depressing than those in many Eastern series. This difference is largely related to the late presentation in the West, as the relatively low incidence does not justify screening programs. However, results equivalent to those in Eastern series are obtained for the small subset of patients who do present with early disease. More than 90% of patients were able to eat satisfactorily and to gain weight after resection, although return to previous best weight occurred infrequently and was usually confined to patients surviving beyond 5 years. Although adjuvant therapy was used little in this series, it is believed that current prospective studies involving amultimodal adjuvant regimens offer the best hope of improving survival.
Lymph node dissection
Authors: Hennessy Thomas P. J.
Published: October 2004

Cervical lymph nodes are involved in 43% of patients with an upper esophageal lesion, 33% of patients with a middle third tumor, and 29% with a tumor of the lower third. Conventional two‐field lymph node dissection removing the abdominal and lower mediastinal lymph node groups leads to inaccurate staging and is inadequate for preventing local recurrence. Three‐field lymphadenectomy involves bilateral removal of the lower cervical groups of nodes, the superior, middle, and inferior mediastinal lymph nodes and the abdominal groups. The advantages of this extended dissection are improved survival, diminished incidence of local recurrence, and more accurate staging. The benefits in terms of improved survival may accrue to patients both with and without cervical lymph node involvement. Three‐field node dissection improves 5‐year survival to around 35% without an increase in the mortality rate. The incidence of recurrent laryngeal nerve paralysis is increased with the operation and could be as high as 14% or more.
Advanced esophageal carcinoma
Authors: Lerut Toni E. , de Leyn Paul , Coosemans Willy , Van Raemdonck Dirk , Cuypers Philippe , Van Cleynenbreughel Ben
Published: October 2004

From 1976 until 1990 a total of 212 patients with squamous cell carcinoma of the thoracic esophagus were referred for surgical treatment. Resectability was 84.1% (161 of 191). Actuarial 5‐year survival in patients with negative lymph nodes was 51.2% versus 12.4% in lymph nodepositive patients. Therefore advanced carcinoma was defined to compromise all patients with involved regional (N1) or distal lymph nodes (M+Ly) as well as patients with T4 tumors or solid organ metastasis (M+org) irrespective of their lymph node status. Comparing complete (R0) versus incomplete (R1–R2) resections for stage III and IV carcinoma revealed 20% and 0% five‐year survivals, respectively. There was no 5‐year survival in the stage IV group. When excluding solid organ metastasis, the median survival shifted from 8.5 months after incomplete (R1–R2) to 20 months after complete (R0) resection. In 1991 three‐field lymphadenectomy was initiated that included bilateral cervical lymphadenectomy. Thirty‐seven patients have been treated so far (23 squamous cell carcinoma, 14 adenocarcinomas). Cervical lymph nodes were positive in 24.3% with an incidence up to 28.5% for distal‐third carcinoma. Subsequently, 6 patients (16%) moved from M0 to M+Ly status. Our results confirm the key role of surgery not only in improving survival and locoregional tumor control but in refining the accuracy of staging advanced carcinomas provided complete resection is possible. Nowadays other options in the treatment of advanced carcinoma are mainly based on neoadjuvant chemoradiotherapy with response rates ranging from 40% to 60% but until now without evidence of improved 5‐year survival rates and with local or distant failure rates of approximately 30% and 45%, respectively. For clinically nonresectable (T4) or presumed nonresectable tumors, neoadjuvant therapy seems to have an important role, as it may convert these tumors into resectable and therefore potentially curable cancers. Toxicity remains a drawback, as it is probably responsible for preoperative dropouts and slight but definitive higher postoperative mortality and morbidity. When the disease clearly is incurable, the best options today are laser therapy and an endoprosthesis, which result in good relief of dysphagia in approximately 80% to 85% of patients and a procedure‐related mortality below 5%.
Quality of life with carcinoma of the esophagus
Authors: Gelfand Gary A. J. , Finley Richard J.
Published: October 2004

Management of squamous carcinoma of the esophagus remains a dilemma for the clinician. Current treatments produce significant morbidity and mortality, yet most patients still die of their disease. Given the limitations, survival alone is insufficient to assess the various options; quality of life (QOL) must also be addressed. This paper reviews the topic of QOL, the various instruments available to measure it, and methods to evaluate such instruments. A 16‐year review of the literature was performed to assess the extent to which QOL has been addressed in patients with esophageal carcinoma. Only 51 of 7569 references on esophageal neoplasms considered QOL. Only 3 used documented QOL instruments with appropriate statistical testing. Currently there is no well validated instrument for measurement of QOL in patients with esophageal carcinoma.
Human parathyroid blood supply determined by laser‐Doppler flowmetry
Authors: Johansson Kenth , Ander Stefan , Lennquist Sten , Smeds Staffan
Published: October 2004

The blood supply of 53 normal human parathyroid glands was studied with laser Doppler flowmetry in 45 patients undergoing operations on the thyroid and parathyroid glands. The inferior and superior thyroid arteries and other vessels that might supply the parathyroid glands were occluded so their contribution to parathyroid perfusion could be studied. Occlusion of the main trunk of the inferior thyroid artery resulted in a reduction of blood flow by one‐third, and a similar reduction was obtained after occlusion of the superior thyroid artery. The results demonstrate that the blood supply to the parathyroid glands is not as dependent on the inferior thyroid artery as has previously been suggested but that other routes of blood supply may be equally or, in some cases, even more important.
Minimizing the risk of bile duct injury at laparoscopic cholecystectomy
Authors: Cox Michael R. , Wilson Thomas G. , Jeans Philip L. , Padbury Robert T. A. , Toouli James
Published: October 2004

The introduction of laparoscopic cholecystectomy (LC) has been associated with an increase in the incidence of operative bile duct injuries. An operative technique that involves commencing the laparoscopic dissection on the body of the gallbladder and dissecting toward the cystic duct has been developed that minimizes the risk of major duct injury. The aim of this study was to assess prospectivel the safety of this dissection technique. A group of 410 patients underwent LC for symptomatic cholelithiasis from January 1991 to December 1992. There was a single common hepatic duct injury: a small (1 mm) side hole in a patient with acute cholecystitis and choledocholithiasis. It was managed at open operation with exploration of the common bile duct and insertion of a T‐tube. There were no partial or complete common bile duct transections in this series. We concluded that the technique of commencing the dissection on the gallbladder is safe and minimizes the risk of serious common bile duct injury at LC.
Clinicopathologic features of gastric cancer infiltrating the lower esophagus
Authors: Takeshita Kimiya , Ashikawa Toshihisa , Tani Masao , Saito Naoya , Maruyama Michio , Sunagawa Masakatsu , Habu Hiroshi , Endo Mitsuo
Published: October 2004

A total of 211 patients with gastric cancer in the upper third of the stomach were clinicopathologically evaluated. Of the 211 patients, 82 had esophageal infiltration and 129 did not. These two groups were compared. The study on patients who had undergone resection and radioisotope (99mTc‐phytate) uptake testing revealed that it was important to dissect the lymph nodes (predominantly nodes 7,9,11, and 16) during surgery in the patients with gastric cancer plus esophageal infiltration. When cancer infiltration of the esophagus exceeds 1 cm, the preferred surgical procedure is lower esophagectomy and total gastrectomy with abdominal and intrathoracic lymphadenectomy via the left thoracoabdominal approach. When residual cancer is suggested in the more proximal esophageal stump due to intramural metastasis from vascular invasion, rapid pathologic diagnosis should be made by frozen sections during surgery and then subtotal esophagectomy by blunt removal of the esophagus proximally from the aortic arch using a left thoracotomy considered.
Hardy–Sobolev critical elliptic equations with boundary singularities
Authors: Ghoussoub N. , Kang X.S.
Published: October 2004

Unlike the non-singular case

s=0

, or the case when 0 belongs to the interior of a domain

Ω

in

ℝ^n

(

n⩾3

), we show that the value and the attainability of the best Hardy–Sobolev constant on a smooth domain

Ω

,

\mu _{s}(\Omega ): = \inf \left\{\int \limits_{\Omega }\left|\nabla u\right|^{2}dx;u∊H_{0}^{1}(\Omega )\text{ and }\int \limits_{\Omega }\frac{\left|u\right|^{2*(s)}}{\left|x\right|^{s}} = 1\right\}

when

0<s<2

,

2^∗(s)=\frac{2(n - s)}{n - 2}

, and when 0 is on the boundary

∂Ω

are closely related to the properties of the curvature of

∂Ω

at 0. These conditions on the curvature are also relevant to the study of elliptic partial differential equations with singular potentials of the form:

- \Delta u = \frac{u^{p - 1}}{\left|x\right|^{s}} + f(x,u)\text{ in }\Omega \subset ℝ^{n},

where

f

is a lower order perturbative term at infinity and

f(x,0)=0

. We show that the positivity of the sectional curvature at 0 is relevant when dealing with Dirichlet boundary conditions, while the Neumann problems seem to require the positivity of the mean curvature at 0.

Contrairement au cas non-singulier

s=0

, ou au cas d’une singularité à l’intérieur d’ un domaine

Ω

de

ℝ^n

(

n⩾3

), on montre que la valeur de la meilleure constante dans l’inégalité de Hardy–Sobolev sur un domaine régulier,

\mu _{s}(\Omega ): = \inf \left\{\int \limits_{\Omega }\left|\nabla u\right|^{2}dx;u∊H_{0}^{1}(\Omega )\text{ et }\int \limits_{\Omega }\frac{\left|u\right|^{2*(s)}}{\left|x\right|^{s}} = 1\right\}

quand

0<s<2

,

2^∗(s)=\frac{2(n - s)}{n - 2}

, et quand 0 appartient à la frontière, est étroitement liée aux propriétés de la courbure de

∂Ω

en 0. Ces mêmes conditions sur la courbure sont aussi pertinentes pour l’existence de solutions d’équations à potentiel singulier de la forme :

- \Delta u = \frac{u^{p - 1}}{\left|x\right|^{s}} + f(x,u)\text{ in }\Omega \subset ℝ^{n},

où

f

est une perturbation d’ordre inférieur à l’infini et

f(x,0)=0

. On montre que la positivité de la courbure sectionelle est suffisante pour l’existence de solutions des problèmes avec conditions de Dirichlet au bord, tandis que pour les problèmes de Neumann, c’est la positivité de la coubure moyenne qui compte.
The P3 domain of E. coli ribonuclease P RNA can be truncated and replaced
Authors: Tanaka Terumichi , Kanda Naomi , Kikuchi Yo
Published: October 2004

We prepared some truncated and replaced P3 mutants of Escherichia coli RNase P RNA, and used them to examine the RNase P ribozyme and holoenzyme reactions of a pre‐tRNA substrate. The results indicated that mutations in the P3 domain did not affect the cleavage site selection of the pre‐tRNA substrate, but did affect the efficiency of cleavage of the substrate. Results of stepwise truncation of the P3 domain and its replacement by the TAR sequence showed that the P3 domain of the E. coli RNase P was able to be truncated to certain length and was replaceable, but could not be deleted in the ribozyme.
Crystal structure of human ISG20, an interferon‐induced antiviral ribonuclease
Authors: Horio Tatsuya , Murai Masatoshi , Inoue Toshihiko , Hamasaki Tomohiro , Tanaka Teruo , Ohgi Tadaaki
Published: October 2004

ISG20 is an interferon‐induced antiviral exoribonuclease that acts on single‐stranded RNA and also has minor activity towards single‐stranded DNA. It belongs to the DEDDh group of RNases of the DEDD exonuclease superfamily. We have solved the crystal structure of human ISG20 complexed with two Mn2+ ions and uridine 5′‐monophosphate (UMP) at 1.9 Å resolution. Its structure, including that of the active site, is very similar to those of the corresponding domains of two DEDDh‐group DNases, the ε subunit of Escherichia coli DNA polymerase III and E. coli exonuclease I, strongly suggesting that its catalytic mechanism is identical to that of the two DNases. However, ISG20 also has distinctive residues, Met14 and Arg53, to accommodate hydrogen bonds with the 2′‐OH group of the UMP ribose, and these residues may be responsible for the preference of ISG20 for RNA substrates.
Islet amyloid polypeptide‐induced membrane leakage involves uptake of lipids by forming amyloid fibers
Authors: Sparr Emma , Engel Maarten F.M. , Sakharov Dmitri V. , Sprong Mariette , Jacobs Jet , de Kruijff Ben , Höppener Jo W.M. , Antoinette Killian J.
Published: October 2004

Fibril formation of islet amyloid polypeptide (IAPP) is associated with cell death of the insulin‐producing pancreatic β‐cells in patients with Type 2 Diabetes Mellitus. A likely cause for the cytotoxicity of human IAPP is that it destroys the barrier properties of the cell membrane. Here, we show by fluorescence confocal microscopy on lipid vesicles that the process of hIAPP amyloid formation is accompanied by a loss of barrier function, whereby lipids are extracted from the membrane and taken up in the forming amyloid deposits. No membrane interaction was observed when preformed fibrils were used. It is proposed that lipid uptake from the cell membrane is responsible for amyloid‐induced membrane damage and that this represents a general mechanism underlying the cytotoxicity of amyloid forming proteins.
Behavioral and cellular consequences of increasing serotonergic activity during brain development: a role in autism?
Authors: Whitaker‐Azmitia Patricia M.
Published: October 2004

The hypothesis explored in this review is that the high levels of serotonin in the blood seen in some autistic children (the so‐called hyperserotonemia of autism) may lead to some of the behavioral and cellular changes also observed in the disorder. At early stages of development, when the blood–brain Barrier is not yet fully formed, the high levels of serotonin in the blood can enter the brain of a developing fetus and cause loss of serotonin terminals through a known negative feedback function of serotonin during development. The loss of serotonin innervation persists throughout subsequent development and the symptoms of autism appear. A review of the basic scientific literature on prenatal treatments affecting serotonin is given, in support of this hypothesis, with an emphasis on studies using the serotonin agonist, 5‐methoxytryptamine (5‐MT).

In work using 5‐MT to mimic hyperserotonemia, Sprague‐Dawley rats are treated from gestational day 12 until postnatal 20. In published reports, these animals have been found to have a significant loss of serotonin terminals, decreased metabolic activity in cortex, changes in columnar development in cortex, changes in serotonin receptors, and “autistic‐like” behaviors. In preliminary cellular findings given in this review, the animals have also been found to have cellular changes in two relevant brain regions: 1. Central nucleus of the amygdala, a brain region involved in fear‐responding, where an increase in calcitonin gene related peptide (CGRP) was found 2. Paraventricular nucleus of the hypothalamus, a brain region involved in social memory and bonding, where a decrease in oxytocin was found. Both of these cellular changes could result from loss of serotonin innervation, possibly due to loss of terminal outgrowth from the same cells of the raphe nuclei. Thus, increased serotonergic activity during development could damage neurocircuitry involved in emotional responding to social stressors and may have relevance to the symptoms of autism.
Strategies to prevent eclampsia in a developing country: I. Reorganization of maternity services
Authors: McCaw‐Binns A.M. , Ashley D.E. , Knight L.P. , MacGillivray I. , Golding J.
Published: October 2004

Objective: To determine whether changes in primary and secondary care service delivery could prevent antenatal eclampsia. Method: One intervention (St. Catherine) and two control (St Ann, Manchester) parishes were chosen. The health system in St. Catherine was restructured. Primary antenatal clinics had clear instructions for referring patients to a high‐risk antenatal clinic or to hospital. Guidelines were provided to high‐risk clinics and the antenatal ward for appropriate treatment of hypertension and preeclampsia when induction of labor should occur. Antenatal eclampsia incidence was monitored before and during the intervention and compared with control parishes (no intervention). Each eclampsia case was investigated to identify inadequacies in the system. Results: The process resulted in better identification of women at risk. Antenatal eclampsia incidence dropped dramatically as care improved. Compared with control areas, by completion of the study, the rate was significantly lower than at the start: OR 0.19 (95% CI: 0.13–0. 27; p<0.001 trend). Antenatal admissions for hypertensive disorders declined significantly, and the number of bed days halved. Conclusion: Reorganization of maternal care can have major public health benefits and cost savings; however, women need to be alerted to recognise and act upon signs of impending eclampsia.
Risk factors and obstetric complications associated with macrosomia
Authors: Stotland N.E. , Caughey A.B. , Breed E.M. , Escobar G.J.
Published: October 2004

Objective

Macrosomia is associated with adverse maternal outcomes. The objective of this study was to characterize the epidemiology of macrosomia and related maternal complications.

Method

Live births (146,526) were identified between 1995 and 1999 in the Kaiser Permanente Medical Care Program's Northern California Region (KPMCP NCR) database. Bivariate and multivariate analyses were performed for risk factors and complications associated with macrosomia (birth weight >4500 g).

Result

Male infant sex, multiparity, maternal age 30–40, white race, diabetes, and gestational age >41 weeks were associated with macrosomia (p<0.001). In bivariate and multivariate analyses, macrosomia was associated with higher rates of cesarean birth, chorioamnionitis, shoulder dystocia, fourth‐degree perineal lacerations, postpartum hemorrhage, and prolonged hospital stay (p<0.01).

Conclusion

Macrosomia was associated with adverse maternal outcomes in this cohort. More research is needed to determine how to prevent complications related to excessive birth weight.
The Effect of Cellular Proliferative Activity on Recurrence and Local Tumour Extent of Localized Giant Cell Tumour of Tendon Sheath
Authors: KITAGAWA Y. , ITO H. , YOKOYAMA M. , SAWAIZUMI T. , MAEDA S.
Published: October 2004

This study investigates whether the proliferative activity of giant cell tumour of tendon sheath is related to its recurrence rate and local aggressiveness. The clinicopathological and immunohistochemical features of 30 localized giant cell tumours of tendon sheath were studied and the influence of the MIB-1 staining index on recurrence, tumour extent around the phalanx and involvement of the bone were evaluated. No significant difference in the MIB-1 staining index was found between the lesions which recurred and those which did not. Also there was no significant association between local aggressiveness and the MIB-1 staining index. These results suggest that the proliferative activity of localized giant cell tumour of tendon sheath is not related to its high recurrence rate and local aggressiveness.
Changing Families as European Societies Age
Authors: HARPER SARAH
Published: October 2004

The trends towards falling fertility and mortality and increasing longevity, which have led to the demographic ageing of all Western industrialized societies, have not occurred in isolation. More specifically, we are also seeing a combination of forces which are resulting in the ageing of some life-transitions. While public and legal institutions may be lowering the age threshold into full legal adulthood, individuals themselves are choosing to delay many of those transitions which demonstrate a commitment to full adulthood. This shift from a high-mortality/high-fertility society to a low-mortality/low-fertility society and the ageing of family transitions within these societies have significant implications for both family structure and kinship roles. Drawing on recent demographic figures for the European Union, this paper highlights the impact of these main trends on individuals and families.
Social Capital and its Uses
Authors: SWAIN NIGEL
Published: October 2004

The article attempts to assess the use and usefulness of the concept of ‘social capital’. First, it assesses its differing conceptual uses in the works of four key writers, Pierre Bourdieu, Gary S. Becker, James S. Coleman and Robert D. Putnam, identifying broadly a problematic ‘social capital as social fact’ perspective associated with Putnam, and a more promising ‘contacts with influential people’ approach that can be derived from Bourdieu. It then considers the practical uses already made of the former approach in the development studies literature, before addressing some of the analytical problems associated with applying the latter in a policy environment. Finally, it takes three short examples from research in rural Central and Eastern Europe to illustrate how the concept can be used to both analyse social relations and suggest policy priorities. The article's conclusion is that ‘social capital’ of any variety is by no means the ‘missing link’ in development economics, yet ‘social capital’ of the Bourdieu-derived kind can be a useful, work-a-day concept in social analysis.
Sociologie du contribuable et évitement de l'impôt
Authors: LEROY MARC
Published: October 2004

This article of fiscal sociology suggests an analytical review of the corpus of models and data relative to the avoidance (legal or not) of the tax so as to establish a cognitive theory of the rationality of the taxpayer. It aspires also to catch the attention of the sociologists for this promising field of research, though still neglected. On the basis of labelling theory of the deviance, of the tax revolt history and fiscal (social) psychology, the rational approach of the taxpayers insists on the importance of the concrete cognitive relation towards tax to explain the phenomena of tax avoidance (or not). It consists both in underlining the limits of the self-interest standard model and in emphasizing the political dimension of the taxation to give credence to the reality of a citizen's conception about the fair taxation (‘contribution-tax’) of the fiscal State in a given context.