bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic and therapeutic endoscopy
Authors: Kuipers E.J. , Haringsma J.
Published: November 2005

Within the gastrointestinal tract, there is no shorter segment with a higher cancer incidence than the gastro‐esophageal junction. Flexible endoscopy is the mainstay for diagnosis of early and advanced esophageal adenocarcinoma, for the treatment of early lesions, and also for the palliation of advanced cancer. New developments in endoscopy aim to improve the diagnosis and treatment of esophageal cancer. These include high resolution and magnification endoscopy in combination with chromendoscopy, and techniques based on modulation of the features of light bundles, such as narrow band imaging, fluorescence endoscopy, and elastic scattering spectroscopy. The value of these techniques for the surveillance of distal esophageal neoplasia needs further study. Furthermore, new methods of tissue sampling and evaluation are being studied to augment identification and staging of patients at risk for cancer. Finally, newer instruments may decrease patient burden during endoscopy, making screening and surveillance more acceptable from a patient's perspective. This review discusses the new developments in flexible endoscopy for diagnosis and therapy of early and advanced and advanced esophageal adenocarcinoma. J. Surg. Oncol. 2005;92:203–209. © 2005 Wiley‐Liss, Inc.
Surgery for early stage esophageal adenocarcinoma
Authors: Stein H.J. , von Rahden B.H.A. , Feith M.
Published: November 2005

Current treatment recommendations for early esophageal adenocarcinoma range from radical esophagectomy with extensive lymphadenectomy, limited surgical resection with/without regional lymphadenectomy to endoscopic mucosectomy or ablation. A comparison of treatment associated morbidity, tumor recurrence rates, and functional outcome suggests that none of these alternatives can be universally recommended. Rather, an individualized strategy should be employed based on depth of tumor penetration into the mucosa/submucosa, presence of lymph node metastases, multicentricity of tumor growth, length of the underlying Barrett mucosa and comorbidity of the affected patient. Endoscopic mucosectomy may suffice for an isolated focus of high‐grade neoplasia or mucosal cancer, provided the neoplasia and underlying Barrett mucosa can be removed completely. Surgical resection is the treatment of choice for tumors invading the submucosa, multicentric tumors and recurrence after endoscopic mucosectomy. The extent of surgical resection must be guided by the length of the Barrett mucosa. In most instances a complete tumor resection and removal of the entire Barrett mucosa can be achieved by a limited transabdominal approach, and therefore subtotal esophagectomy may not be necessary. Application of the sentinel node technology may in the future allow to limit systematic lymphadenectomy to the rather small subgroup of patients who in fact have lymph node metastases. J. Surg. Oncol. 2005;92:210–217. © 2005 Wiley‐Liss, Inc.
Surgical techniques
Authors: Lerut T. , Coosemans W. , Decker G. , De Leyn P. , Moons J. , Nafteux P. , Van Raemdonck D.
Published: November 2005

Adenocarcinoma of the esophagus and gastroesophageal junction (GEJ) has shown a remarkable increase during recent decades. Most patients are present with advanced stage disease, reflecting transmural growth and metastasis to lymph nodes at the time of diagnosis. Moreover, the pattern of lymph node dissemination is chaotic and difficult to predict, and despite the use of modern technology (e.g., spiral CT, EUS, FDG‐PET), clinical staging remains suboptimal. These shortcomings in staging, as well as in different attitudes toward extent of resection and lymphadenectomy, are reflected by a great variation in surgical techniques, which are discussed in this review. As to the results, primary surgery can currently be performed with low mortality, below 5% in high volume centers. Hospital mortality and morbidity are mainly related to pulmonary complications and anastomotic leaks, the latter mostly resolving under conservative treatment. Overall 5‐year survival varies between 10% and 59%. As expected the most important prognostic determinants are completeness of resection (R0 vs. R1–R2) and lymph node status (N0, N1). R0 resection currently offers 5‐year survival rates of over 40%. Five‐year survival figures for node‐negative (N0) patients exceed 70%, and even for node‐positive (N1), patients reach 25%. It is not known whether performing a three‐field lymph node dissection is beneficial for patients with adenocarcinoma of the distal esophagus. With overall 5‐year survival currently exceeding 30%–40%, these figures should be the gold standard against which all other therapeutic modalities are compared. J. Surg. Oncol. 2005;92:218–229. © 2005 Wiley‐Liss, Inc.
Neoadjuvant and adjuvant chemotherapy for esophageal adenocarcinoma
Authors: Mooney M.M.
Published: November 2005

The poor outcome associated with surgical resection alone for most patients with locoregional esophageal cancer has generated intensive investigation of combined‐modality treatment approaches that include systemic chemotherapy. This review discusses the current role of chemotherapy in the treatment of patients with adenocarcinoma of the esophagus, given in either the pre‐operative (neoadjuvant) or post‐operative (adjuvant) setting compared to surgery alone, highlighting the results of large, randomized clinical trials that included patients with adenocarcinoma of the esophagus as well as some of the approaches being evaluated with novel therapies in earlier phase clinical trials. Although no definitive recommendations for pre‐operative or post‐operative treatment can be made for patients with adenocarcinoma of the esophagus based on outcomes reported in randomized clinical trials performed to date, the results from these trials suggest chemotherapy or chemoradiation in the peri‐operative period may have benefit, especially in certain sub‐groups. Newer, more effective agents are needed as well as methods to identify which tumors will respond to therapy. Improvement in outcomes for patients with this disease will require rigorous evaluation of newer multi‐modality regimens in well‐designed and appropriately powered clinical trials. J. Surg. Oncol. 2005;92:230–238. © 2005 Wiley‐Liss, Inc.
Radiation and chemoradiation therapy for esophageal adenocarcinoma
Authors: Bosset Jean‐Franois , Lorchel F. , Mantion G. , Buffet J. , Créhange G. , Bosset M. , Chaigneau L. , Servagi S.
Published: November 2005

The aims of preoperative chemoradiation therapy (preop‐CRT) for esophageal adenocarcinoma are to reduce incomplete local resection (R1,R2), local and systemic recurrences that are reported in up to 30% of patients who undergo surgery alone. Phase II studies of preop‐CRT, with radiation doses in the 40–50 Gy range, and concurrent chemotherapy with 5‐fluorouracil (5‐FU)–cisplatin ± paclitaxel, or cisplatin–paclitaxel, have reported subsequent RO resection rates of 80%–100%, with tumor sterilization achieved in 8%–49% of cases, and consequently improved local control. New chemotherapy regimens omitting 5‐FU have reduced the incidence of severe esophagitis, unplanned hospitalization, with comparable efficacy. Among three randomised trials that compared preop‐CRT to surgery alone, one shown a debatable survival advantage. Reducing local recurrence rates lead to a switch to more distant failures, and increasing the radiation dose beyond 45 Gy appears to be of little value. However, it should be remembered that preop‐CRT has associated toxicity, and may increase postoperative mortality. Novel strategies, which include induction with chemotherapy followed by preop‐CRT, and for radiation therapy, three dimensional conformation techniques, image fusioning, and improved definition of treatment volumes, are still considered experimental and should be tested in specialized centers. J. Surg. Oncol. 2005;92:239–245. © 2005 Wiley‐Liss, Inc.
Palliative therapy
Authors: Homs Marjolein Y.V. , Kuipers Ernst J. , Siersema Peter D.
Published: November 2005

There are a wide variety of palliative treatments for esophageal cancer. The aim of most treatments is to maintain oral food intake, which should stabilize or even improve quality of life. Stent placement is currently the most widely used treatment modality for palliation of dysphagia from esophageal cancer. Stent placement offers a rapid relief of dysphagia, however, the rate of complications (late hemorrhage) and recurrent dysphagia (stent migration, tumor overgrowth) is relatively high. The scientific evidence to advocate the use of anti‐reflux stents for the prevention of gastro‐esophageal reflux is currently too low. Photodynamic therapy is mostly used in North America; however, due to the high costs of the treatment, the long‐lasting side effects and the necessity of repeated treatments, it is not an ideal treatment for palliation of malignant dysphagia. Nd:YAG laser is a relatively effective and safe treatment modality, although laser treatment is also expensive, technically difficult and requiring repeated treatment sessions at 4–6 weeks intervals. Single dose brachytherapy compares favorably to stent placement in long‐term effectiveness and safety. Effective treatment strategies are probably 12 Gy given in one fraction or 16 Gy given in two fractions. Palliative chemotherapy offers response rates in recent trials (including partial and complete responses) ranging from 35% to 50%. Whether palliative chemotherapy also results in a survival benefit is not established yet. For clinical trials on palliation of esophageal cancer, the measurement of quality of life is an important outcome measure. The cancer‐specific EORTC QLQ‐C30 and the esophageal cancer‐specific EORTC‐OES‐18 are validated measures for establishing quality of life status. For the future, a multimodality approach with stent placement or brachytherapy in combination with chemotherapy may be indicated. J. Surg. Oncol. 2005;92:246–256. © 2005 Wiley‐Liss, Inc.
Novel molecular targeted therapy for esophageal cancer
Authors: Schrump David S. , Nguyen Dao M.
Published: November 2005

Esophageal cancers are highly lethal neoplasms which are generally refractory to conventional multidisciplinary interventions. Recent elucidation of the mechanisms of esophageal carcinogenesis, as well as preclinical studies utilizing chromatin remodeling agents and inhibitors of oncogene signaling in conjunction with conventional chemotherapeutic agents provide new opportunities for the development of potentially efficacious molecular targeted therapies for these malignancies. J. Surg. Oncol. 2005;92:257–261. © 2005 Wiley‐Liss, Inc.
Improving outcomes after esophagectomy: The impact of operative volume
Authors: Casson Alan G. , van Lanschot J. Jan B.
Published: November 2005

Once considered an uncommon malignancy, primary esophageal adenocarcinoma has increased steadily in incidence over the past three decades. Despite advances in multimodality therapy, the prognosis for this tumor is generally poor. Surgical resection and reconstruction of the upper gastrointestinal tract is the current standard of care for localized esophageal cancer, but despite advances in perioperative care, still remains a relatively high‐risk surgical procedure. Increasing numbers of reports published over the past decade have documented a clear volume‐outcome relationship for several complex surgical procedures, and in particular for esophagectomy. The clinical implications of this association are reviewed in this section. J. Surg. Oncol. 2005;92:262–266. © 2005 Wiley‐Liss, Inc.
Novel Supramolecular Polymers Based on Zinc‐Salen Chromophores for Efficient Light‐Emitting Diodes
Authors: Peng Qiang , Xie Minggui , Huang Yan , Lu Zhiyun , Cao Yong
Published: November 2005

Summary: A novel series of supramolecular polymers based on zinc‐salen chromophores were readily prepared via ligand‐metal coordination. These polymers were characterized by FT‐IR, NMR, GPC and elemental analysis. All the polymers were readily soluble in common organic solvents and had substantially good thermal properties. Cyclic voltammetry revealed they had LUMO energy levels ranging from −3.20 to −3.23 eV and HOMO energy levels ranging from −6.13 to −6.15 eV. The polymer films can emit strong green photoluminescence (PL) with relatively high quantum efficiencies of 42–51%. Light‐emitting diodes with the configuration ITO/PEDOT/polymer/BCP/Alq3/LiF/Al were efficient green emitters, with maximum current efficiencies of 0.9–2.3 cd · A−1. The preliminary EL results thus suggest that these polymers are potential candidates for efficient green emission in polymer LEDs.

Structures of polymers produced.

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Structures of polymers produced.
Diffusion behavior in polymer–clay nanocomposites
Authors: Sorrentino A. , Tortora M. , Vittoria V.
Published: November 2005

This paper reviews our previous studies on the diffusion behavior in polymers clay nanocomposites. A geometric model for predicting the effective diffusivity through this type of systems as a function of clay sheets orientation, volume fraction, polymer clay interaction, and aspect ratio is proposed. Model predictions are compared to the effective diffusivity generated using random walk simulations as well as with predictions obtained from already existing theoretical models. Fair agreement is found between the model prediction and the results of numerical simulations. With respect to the already existing theoretical models, the present mathematical derivation seems more adequate to describe diffusion behavior in conventional nanocomposites systems (i.e. when fillers present very low values of volume to surface ratio). Experimental diffusion tests are discussed and interpreted with the aid of the proposed model. In addition to the aspect ratio and clay concentration, the polymer clay interactions as well as the sheets orientation are the factors controlling the barrier properties of polymer‐layered silicate nanocomposites. Good agreement was found in the case of samples containing exfoliated clay, whereas the model fails in the case of micro‐composites, in which the inorganic lamellae are agglomerated in clusters. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 265–274, 2006
Methyl dynamics for understanding hydrophobic core packing of dynamically different motifs of double‐stranded RNA binding domain of protein kinase R
Authors: Barnwal Ravi P. , Chaudhuri Tista R. , Nanduri S. , Qin J. , Chary K.V.R.
Published: November 2005

Double‐stranded RNA binding domains of human protein kinase R (dsRBD‐PKR) regulate distinct cellular functions and the fate of an RNA molecule in the cell. This highly homologous domains present in multiple copies in a number of species, exhibit individual and specific functional specificity. Number of NMR and X‐ray crystallographic structural studies reveals that such domains take a common α‐β‐β‐β‐α tertiary fold. However, the functional specificities of these domains could be due to the dynamics of the individual amino acid residues, as has been shown earlier in the case of backbone dynamics of 15N‐1H of dsRNA binding motifs (dsRBMs) of human protein kinase R (PKR) (Nanduri S, Rahman F, Williams BRG, Qin J. EMBO J 2000;19:5567–5574). To further investigate if the differences in dynamics of the two dsRBMs are restricted to only backbone, or if the side‐chain motions are also different to the extent of influencing their packing of the two hydrophobic cores, we have investigated the methyl group dynamics using 13C‐methyl relaxation measurements. The results show that the hydrophobic core of dsRBM1 is more tightly packed than dsRBM2, and it seems to undergo less fast scale motions in the subnanosecond regime. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Role of extracellular signal‐regulated protein kinase and phosphatidylinositol 3‐kinase in neuronal cell death and survival
Authors: Thiel Gerald , Bauer Inge , Rössler Oliver G.
Published: November 2005

The survival of neurons requires, at some point, the presence of neurotrophic factors and depends on competition for a limited supply of survival factors. The neurotrophin brain‐derived neurotrophic factor (BDNF) is the ligand for the TrkB neurotrophin receptor, the most abundant Trk receptor in the brain. Two key signaling pathways are induced following binding of BDNF to its cognate receptor that are characterized by the activation of extracellular signal‐regulated protein kinase (ERK) and phosphatidylinositol 3‐kinase (PI3 kinase). Many reports have assigned a cellular survival function to the activation of ERK and/or PI3 kinase, in line with the reported neuroprotective activity of neurotrophin receptor activation. The activation of PI3 kinase by BDNF represents the dominant survival pathway, whereas the ERK signaling pathway has no or only a marginal role. However, a sustained activation of ERK, lasting for several hours, protects neurons from growth factor deprivation‐induced cell death, indicating that the duration of ERK activation is of major importance for its neuroprotective biological function. The activation of ERK and PI3 kinase does not provide protection against oxidative glutamate toxicity. Thus, the biochemical events underlying neuronal cell death induction by the lack of trophic support or via oxidative stress are distinct.
Transmembrane Signaling in the Brain by Serotonin, A Key Regulator of Physiology and Emotion
Authors: Adayev Tatyana , Ranasinghe Buddima , Banerjee Probal
Published: November 2005

Serotonin (5-HT) is an ancient chemical that plays a crucial functional role in almost every living organism. It regulates platelet aggregation, activation of immune cells, and contraction of stomach and intestinal muscles. In addition, serotonin acts as a neurotransmitter in the brain and the peripheral nervous system. These activities are initiated by the binding of serotonin to 15 or more receptors that are pharmacologically classified into seven groups, 5-HT1 through 5-HT7. Each group is further divided into subgroups of receptors that are homologous but are encoded by discrete genes. With the exception of the 5-HT3 receptor-a cation channel—all of the others are G protein-coupled receptors that potentially activate or inhibit a large number of biochemical cascades. This review will endeavor to compare and contrast such signaling pathways with special attention to their tissue-specific occurrence, their possible role in immediate effects on covalent modification of other proteins, and relatively slower effects on gene expression, physiology and behavior.
Sex differences in cardiac and autonomic response to clinical and experimental pain in LBP patients
Authors: Tousignant‐Laflamme Yannick , Marchand Serge
Published: November 2005

Rehabilitation professionals are currently using heart rate (HR) in order to assess the sincerity of effort in certain evaluations. It has been shown that a relation exists between HR and pain but no study has measured cardiac response during both clinical and experimental pain among a patient population using an intra‐subject design. Thirty patients with low back pain (LBP) participated in this study including 16 men. Clinical pain was induced by applying a postero‐anterior pressure (PA) on a painful lumbar segment for 15 and 30 s in order to reproduce the patient's typical LBP at an intensity ranging between 50 and 70/100. Experimental pain was induced with a 15 s thermal stimulus at a temperature which reproduced the same pain intensity as the 15 s PA. For both reproduced clinical pain durations, we observed a rise in HR ranging between 8.5% and 12.67%. However, unlike men, women's cardiac response failed to show a constant rise in HR during the 30 s PA. For all subjects, the rise in HR was much lower during the experimental pain condition (p < 0.001), reaching only 5%. On the other hand, galvanic skin responses were significantly higher during the experimental pain condition (p < 0.001). During this same condition, women also had a greater rise in galvanic skin responses than men (p = 0.04). Finally, a significant correlation was found between both types of pain. These results suggest that pain induced during a clinical evaluation will produce a significant HR augmentation. However, heart rate variability analysis showed greater sympathetic cardiac regulation for men. The sex differences observed in this study call for caution when interpreting HR during pain assessment.
Combining indicator trends to assess ongoing changes in exploited fish communities: diagnostic of communities off the coasts of France
Authors: Rochet Marie-Joëlle , Trenkel Verena , Bellail Robert , Coppin Franck , Le Pape Olivier , Mahé Jean-Claude , Morin Jocelyne , Poulard Jean-Charles , Schlaich Ivan , Souplet Arnauld , Vérin Yves , Bertrand Jacques
Published: November 2005

We present a method for combining individual indicator results into a comprehensive diagnostic of fishing impacts on fish populations and communities. A conceptual framework for interpreting combined trends in a set of simple indicators is proposed, relying beforehand on qualitative expectations anchored in ecological theory. The initial state of the community is first assessed using published information. Which combinations of trends are acceptable or undesirable is decided, depending on the initial status. The indicators are then calculated from a time-series and their time trends are estimated as the slopes of linear models. Finally, the test results are combined within the predefined framework, providing a diagnostic on the dynamics of fishing impacts on populations and communities. The method is demonstrated for nine coastal and shelf-sea fish communities monitored by French surveys. Most communities were persistently or increasingly impacted by fishing. In addition, climate change seems to have contributed to changes in East Atlantic communities.

Cet article propose une méthode utilisant des indicateurs pour élaborer un diagnostic sur les effets de la pêche sur les populations et les peuplements de poissons. Un cadre conceptuel permet d'interpréter les tendances conjointes d'indicateurs à partir de la théorie écologique. L'état initial du peuplement est d'abord évalué sur la base d'informations publiées. En fonction de l'état initial et des objectifs de gestion, les combinaisons des tendances sont qualifiées d'indésirables ou satisfaisantes. Les indicateurs sont ensuite estimés à partir de données de campagnes de pêches scientifiques: abondance et longueur moyenne d'une sélection de populations, nombre, biomasse totale, poids moyen et longueur moyenne dans le peuplement, et la pente du spectre de taille multispécifique. Les tendances temporelles de ces indicateurs sont testées au moyen d'un modèle linéaire, et les résultats des tests sont combinés en un diagnostic final. La méthode est mise en œuvre pour neuf peuplements de poissons côtiers et du plateau continental, suivis par des campagnes françaises. Il en résulte que la plupart de ces peuplements sont affectés par la pêche de manière stationnaire ou croissante. Par ailleurs, les changements climatiques dans l'Atlantique Nord-Est contribuent aussi à des modifications dans les peuplements de poissons de cette région.
Chromosomal phylogeny of Robertsonian races of the house mouse on the island of Madeira: testing between alternative mutational processes
Authors: BRITTON-DAVIDIAN JANICE , CATALAN JOSETTE , RAMALHINHO MARIA DA GRAÇA , AUFFRAY JEAN-CHRISTOPHE , CLAUDIA NUNES ANA , GAZAVE ELODIE , SEARLE JEREMY B. , MATHIAS MARIA DA LUZ
Published: November 2005

The ancestral karyotype of the house mouse (Mus musculus) consists of 40 acrocentric chromosomes, but numerous races exist within the domesticus subspecies characterized by different metacentric chromosomes formed by the joining at the centromere of two acrocentrics. An exemplary case is present on the island of Madeira where six highly divergent chromosomal races have accumulated different combinations of 20 metacentrics in 500–1000 years. Chromosomal cladistic phylogenies were performed to test the relative performance of Robertsonian (Rb) fusions, Rb fissions and whole-arm reciprocal translocations (WARTs) in resolving relationships between the chromosomal races. The different trees yielded roughly similar topologies, but varied in the number of steps and branch support. The analyses using Rb fusions/fissions as characters resulted in poorly supported trees requiring six to eight homoplasious events. Allowance for WARTs considerably increased nodal support and yielded the most parsimonious trees since homoplasy was reduced to a single event. The WART-based trees required five to nine WARTs and 12 to 16 Rb fusions. These analyses provide support for the role of WARTs in generating the extensive chromosomal diversification observed in house mice. The repeated occurrence of Rb fusions and WARTs highlights the contribution of centromere-related rearrangements to accelerated rates of chromosomal change in the house mouse.
Suicidal behaviour among primary-care patients with depressive disorders
Authors: VUORILEHTO M. S. , MELARTIN T. K. , ISOMETSÄ E. T.
Published: November 2005

Background. Most national suicide prevention strategies set improved detection and management of depression in primary health care into a central position. However, suicidal behaviour among primary-care patients with depressive disorders has been seldom investigated.

Method. In the Vantaa Primary Care Depression Study, a total of 1119 primary-care patients in the City of Vantaa, Finland, aged 20 to 69 years, were screened for depression with the Primary Care Evaluation of Mental Disorders (PRIME-MD) questionnaire. Depressive disorders were diagnosed with the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I), and the 137 patients with depressive disorder were included in the study. Suicidal behaviour was investigated cross-sectionally and retrospectively in three time-frames: current, current depressive episode, and lifetime. Current suicidal ideation was measured with the Scale for Suicidal Ideation (SSI), and previous ideation and suicide attempts were evaluated based on interviews plus medical and psychiatric records.

Results. Within their lifetimes, 37% (51/137) of the patients had seriously considered suicide and 17% (23/137) attempted it. Lifetime suicidal behaviour was independently and strongly predicted by psychiatric treatment history and co-morbid personality disorder, and suicidal behaviour within the current episode was predicted most effectively by severity of depression.

Conclusions. Based on these findings and their convergence with studies of completed suicides, prevention of suicidal behaviour in primary care should probably focus more on high-risk subgroups of depressed patients, including those with moderate to severe major depressive disorder, personality disorder or a history of psychiatric care. Recognition of suicidal behaviour should be improved. The complex psychopathology of these patients in primary care needs to be considered in targeting preventive efforts.
SHOULD CITIZENS OF A WELFARE STATE BE TRANSFORMED INTO “QUEENS”? A RESPONSE TO RISSE
Authors: LE GRAND JULIAN
Published: November 2005

Mathias Risse has provided a thoughtful critique of my book, raising serious points about a major part of the argument. I am glad to have the opportunity to reflect further on it.
Ocean‐atmosphere in situ observations at the Brazil‐Malvinas Confluence region
Authors: Pezzi L. P. , Souza R. B. , Dourado M. S. , Garcia C. A. E. , Mata M. M. , Silva‐Dias M. A. F.
Published: November 2005

This paper presents a description of marine atmospheric boundary layer (MABL) and oceanic boundary layer (OBL) interactions at the Brazil‐Malvinas Confluence. Although this region is known as one of the most energetic zones of the World Ocean, very few studies have addressed the mechanisms of OA interaction there. Based upon novel, direct in situ simultaneous OA observations, our results show that the OBL‐MABL exchanges are closely correlated with the sea surface temperature (SST) field. The heat fluxes range from 110 W.m−2 over warm waters down to 18 W.m−2 over cold waters. Higher heat fluxes and air‐sea temperature differences are associated with stronger near‐surface winds. This suggests that the MABL is modulated at the synoptic temporal and spatial scale by the strong surface thermal gradients between the (warm) Brazil and the (cold) Malvinas (Falklands) currents.
Effect of Duration of Osmotherapy on Blood–Brain Barrier Disruption and Regional Cerebral Edema after Experimental Stroke
Authors: Chen Chih-Hung , Toung Thomas JK , Sapirstein Adam , Bhardwaj Anish
Published: November 2005

Osmotherapy is the cornerstone of medical management for cerebral edema associated with large ischemic strokes. We determined the effect of duration of graded increases in serum osmolality with mannitol and hypertonic saline (HS) on blood-brain barrier (BBB) disruption and regional cerebral edema in a well-characterized rat model of large ischemic stroke. Halothane-anesthetized adult male Wistar rats were subjected to transient (2-h) middle cerebral artery occlusion (MCAO) by the intraluminal occlusion technique. Beginning at 6 h after MCAO, rats were treated with either no intravenous fluids or a continuous intravenous infusion (0.3 mL/h) of 0.9% saline, 20% mannitol, 3% HS, or 7.5% HS for 24, 48, 72, and 96 h. In the first series of experiments, BBB permeability was quantified by the Evans blue (EB) extravasation method. In the second series of experiments, water content was assessed by comparing wet-to-dry weight ratios in six predetermined brain regions. Blood-brain barrier disruption was maximal in rats treated with 0.9% saline for 48 h, but did not correlate with increases in serum osmolality or treatment duration with osmotic agents. Treatment with 7.5% HS attenuated water content in the periinfarct regions and all subregions of the contralateral nonischemic hemisphere to a greater extent than mannitol did with no adverse effect on survival rates. These data show that (1) BBB integrity is not affected by the duration and degree of serum osmolality with osmotic agents, and (2) attenuation of increases in brain water content with HS to target levels > 350 mOsm/L may have therapeutic implications in the treatment of cerebral edema associated with ischemic stroke.
Primary and secondary relaxations in bis-5-hydroxypentylphthalate revisited
Authors: Ngai K. L. , Kamińska E. , Sekuła M. , Paluch M.
Published: November 2005

The molecular structure of bis-5-hydroxypentylphthalate (BHPP) is like dihexyl phthalate but having appended to it two hydroxyl end groups, which contribute additional dipole moments and capacity for hydrogen-bond formation. In a previously published dielectric study of the primary and secondary relaxations of BHPP, it was found that all the dynamic properties are normal except for the anomalously large width of the primary relaxation loss peak. There are two secondary relaxations, the relaxation time of the slower one increases with increasing pressure, whereas that of the faster one is practically insensitive to pressure. Hence, the slower secondary relaxation is the “universal” Johari-Goldstein (JG) [J. Chem. Phys. 53, 2372 (1970); 55, 4245 (1971)] relaxation in BHPP. All is well except if the observed large width of the primary relaxation were an indication of a corresponding large coupling parameter n=0.45 in the coupling model. Then the predicted relations between the primary relaxation time τα and the JG relaxation time τJG found previously to hold in many glass formers would be violated. It was recognized that this singular behavior of BHPP is likely due to broadening of the primary loss peak by the overlapping contributions of two independent dipole moments present in BHPP, and the actual coupling parameter is smaller. However, at the time of publication of the previous work there were not enough data to support this explanation. By making broadband dielectric measurements of dibutyl phthalate (DBP) and dioctyl phthalate (DOP) that have chemical structures closely related to BHPP but with only one dipole moment, we show that all their dynamic properties are almost the same as BHPP but the widths of their primary relaxation loss peaks are significantly narrower corresponding to a smaller coupling parameter n=0.34. The new data presented here indicate that the coupling parameter of BHPP is about the same as DBP and DOP, and the predicted relations between τα and τJG of BHPP are brought back in agreement with the experimental data.
Size effect of Pb0.92Nd0.08(Zr0.53Ti0.47)0.98O3 nanoceramic synthesized by high-energy ball milling
Authors: Parashar S. K. S. , Choudhary R. N. P. , Murty B. S.
Published: November 2005

The nanocrystalline Pb0.92Nd0.08(Zr0.53Ti0.47)0.98O3 (PNZT) has been synthesized by high-energy ball milling (mechanical alloying). X-ray diffraction studies shows that these compounds are tetragonal. Detailed studies of impedance and dielectric properties of PNZT as a function of temperature (and frequency) showed the high permittivity of 10 626 at 10kHz at the Curie temperature (TC), broadening of permittivity peak, lowering of TC, decrease in conductivity, and increase in relaxation time with the decrease in crystallite size.
Adsorption dynamics of CO2 on copper-precovered ZnO(0001)–Zn: A molecular-beam scattering and thermal-desorption spectroscopy study
Authors: Wang J. , Funk S. , Burghaus U.
Published: November 2005

Initial, S0, as well as coverage-dependent adsorption probability measurements, S(Θ), have been conducted at normal impact angle and as a function of the impact energy of CO2, Ei, adsorption temperature, Ts, and copper precoverage, ΘCu (at 300K). S0, which decreased from ∼0.4 exponentially to ∼0.05 with Ei was independent of ΘCu. Astonishingly, S0 for Cu on ZnO(0001)–Zn is smaller than for the clean support which indicates a chemical modification of the support by the Cu deposits. S(Θ) curves consist of two regimes, a Kisliuk-type and Langmuirian-type section. The first is consistent with capture zone models; the second may indicate direct adsorption of CO2 on the Cu cluster. The thermal-desorption (TDS) curves for Cu on ZnO(0001)–Zn consist of two structures with binding energies of 26 and ∼40kJ∕mol (ν=1×1013l∕s). The TDS results indicate that CO2 populates predominantly the Cu deposits and the rim along the Cu nanoparticles. No indications for CO2 dissociation could be obtained with Auger electron spectroscopy.
Measurement of thermo-optic properties of Y3Al5O12, Lu3Al5O12, YAIO3, LiYF4, LiLuF4, BaY2F8, KGd(WO4)2, and KY(WO4)2 laser crystals in the 80–300K temperature range
Authors: Aggarwal R. L. , Ripin D. J. , Ochoa J. R. , Fan T. Y.
Published: November 2005

Thermo-optic materials properties of laser host materials have been measured to enable solid-state laser performance modeling. The thermo-optic properties include thermal diffusivity (β), specific heat at constant pressure (Cp), thermal conductivity (κ), coefficient of thermal expansion (α), thermal coefficient of the optical path length (γ) equal to (dO∕dT)∕L, and thermal coefficient of refractive index (dn∕dT) at 1064nm; O denotes the optical path length, which is equal to the product of the refractive index (n) and sample length (L). Thermal diffusivity and specific heat were measured using laser-flash method. Thermal conductivity was deduced using measured values of β, Cp, and the density (ρ). Thermal expansion was measured using a Michelson laser interferometer. Thermal coefficient of the optical path length was measured at 1064nm, using interference between light reflected from the front and rear facets of the sample. Thermal coefficient of the refractive index was determined, using the measured values of γ, α, and n. β and κ of Y3Al5O12, YAIO3, and LiYF4 were found to decrease, as expected, upon doping with Yb.
Dielectric relaxation processes in water mixtures of tripropylene glycol
Authors: Grzybowska K. , Grzybowski A. , Pawlus S. , Hensel-Bielowka S. , Paluch M.
Published: November 2005

Broadband dielectric measurements for anhydrous tripropylene glycol (3PG) and 96, 92, 84, 80, 74, 71, and 68wt% 3PG-water mixtures are performed in the frequency range of 10−2–107Hz and in the temperature range of 123–243K. We examined the effect of adding water into anhydrous 3PG on relaxation dynamics. Apart from the two well-known relaxation processes, i.e., α and β for anhydrous 3PG we observed new relaxation peak (β′) for all aqueous mixtures of 3PG. In addition we found the critical mole fraction of water xw=0.67 in which relaxation dynamics changes its behavior. According to the Sudo approach [S. Sudo et al., J. Non-Cryst. Solids 307–310, 356 (2002)], the behavior of relaxation processes was interpreted assuming the existence of three kinds of cooperative domains (CDs): containing only 3PG molecules, including only water molecules, and including both 3PG and water molecules, which molecules of each kind CD are bound by hydrogen bonds.
Roughness evolution in thin-film growth of SiO2 and Nb2O5
Authors: Elsholz F. , Schöll E. , Scharfenorth C. , Seewald G. , Eichler H. J. , Rosenfeld A.
Published: November 2005

We investigate the amorphous thin-film growth of SiO2 and Nb2O5 on glass substrates and quantify the roughness of the film surface by means of a statistical data analysis of atomic force microscopy images. We determine the absolute root-mean-square roughness, the effective growth exponent β, the local roughness exponent α, and the evolution of the lateral correlation length ξa for dual magnetron sputter-deposited thin films.
Characterization of Au and Al segregation layer in post-annealed thin Ti∕Al∕Mo∕Au Ohmic contacts to n-GaN
Authors: Wang Liang , Mohammed Fitih M. , Adesida Ilesanmi
Published: November 2005

The post-annealed interfacial microstructures of thin Ti∕Al∕Mo∕Au metallization on n-GaN were investigated using analytical transmission electron microscopy. A 5–20-nm-thick continuous TiN layer was observed to have been formed due to the reaction between Ti and GaN. A continuous Au and Al segregation with a narrow thickness occurring exactly at the TiN∕GaN interface was identified. Detailed structure and composition of the segregation layer were characterized. It is noted that despite the presence of Au at the interfacial region, an excellent Ohmic contact resistance was obtained. It suggests that the segregation of Au at the semiconductor∕metal interface does not necessarily have detrimental effects on contact performance.
Influence of composition pulling effect on the two-dimensional electron gas formed at AlyInxGa1−x−yN∕GaN interface
Authors: Soh C. B. , Chua S. J. , Tripathy S. , Chow S. Y. , Chi D. Z. , Liu W.
Published: November 2005

The piezoelectric field generated at the AlyInxGa1−x−yN∕GaN interface creates a two-dimensional electron gas (2DEG). The maximum 2DEG mobility in AlyInxGa1−x−yN∕GaN, for a nominal composition of x=0.01 and y=0.07, is obtained for the 40-nm-thick quaternary epilayer. With further increase in the AlyInxGa1−x−yN thickness, the mobility drops due to the generation of V defects and misfit dislocations. The 2DEG carrier concentration increases with the thickness due to the composition pulling effect observed during growth where the Al content increases toward the surface. This effect coupled with the stronger piezoelectric field results in a significant band bending and a deeper potential well is created for the sample with a thicker AlInGaN epilayer. The integrated intensity ratio of the photoluminiscence emission from the 2DEG and the AlInGaN band-edge emission, I2DEG∕IBE, is studied as a function of temperature for AlInGaN epilayers of different thickness. The effect of strain relaxation and V-pit formation on the 2DEG confinement in AlInGaN∕GaN is also discussed.
Hydrogen-discriminating nanocrystalline doped-tin-oxide room-temperature microsensor
Authors: Shukla Satyajit , Zhang Peng , Cho Hyoung J. , Rahman Zia , Drake Christina , Seal Sudipta , Craciun Valentin , Ludwig Lawrence
Published: November 2005

Highly hydrogen (H2)-selective [relative to carbon monoxide (CO)] sensor, operating at room temperature, has been fabricated using the micronanointegration approach involving the deposition of the nanocrystalline indium oxide (In2O3)-doped tin oxide (SnO2) thin film on microelectromechanical systems device. The present microsensor exhibits high room-temperature sensitivity towards H2 (S=12700); however, it is insensitive to CO at room temperature. In view of the different gas selectivity mechanisms proposed in the literature, it is deduced that the In2O3 doping, the presence of InSn4 phase, the low operating temperature (room temperature), the mesostructure, the small sizes of H2 and H2O molecules, the bulky intermediate and final reaction products for CO, and the electrode placement at the bottom are the critical parameters, which significantly contribute to the high room-temperature H2 selectivity of the present microsensor over CO. The constitutive equation for the gas sensitivity of the semiconductor oxide thin-film sensor, proposed recently by the authors, has been modified to qualitatively explain the observed H2 selectivity behavior.
Mean drift velocity in viscous flow over a corrugated bottom
Authors: Weber Jan Erik H.
Published: November 2005

The mean, steady-state particle velocity in pressure-driven viscous flow in a horizontal channel with a sinusoidal bottom and a plane top is computed using a Lagrangian description of motion. The bottom corrugations are longitudinal, i.e., having crests aligned along the basic flow. At the bottom a no-slip condition is applied. At the upper boundary two different cases are considered: one stress free and one no slip. The nonlinear interaction between the basic Poiseuille flow and the bottom corrugations yields a mean Lagrangian drift velocity that is directed along the basic flow for small nondimensional wave numbers, and against the basic flow for larger wave numbers. More specifically, the entire mean drift velocity is negative for stress-free and no-slip upper boundaries when the wave number for the two cases exceeds 1.35 and 2.28, respectively. It is demonstrated that the total nonlinear wall drag is zero for both these cases. The results for longitudinal corrugations are compared with earlier calculations for bottom corrugations that are transverse to the basic flow. In that case the nonlinear mean drift current is always directed against the basic flow. It is found that for the same wave number, transverse corrugations induce a stronger negative mean drift velocity than do longitudinal corrugations.
Spectrum of electromagnetic excitations in a dc-biased semiconductor superlattice
Authors: Raspopin A. S. , Zharov A. A. , Cui H. L.
Published: November 2005

We analyze the spectrum and stability of transverse electromagnetic excitations in a dc-biased semiconductor superlattice in a microstrip line geometry. We show the existence of a critical dc field strength that corresponds to equality of the Bloch frequency and the electron plasma frequency at the bottom of the miniband. At this field strength the frequency–wave-number dispersion curves change their character. For a subcritical dc field, the spectrum of electromagnetic excitations consists of propagating transverse electromagnetic wave and quasistatic Bloch oscillations. In the case of overcritical dc field, transverse electromagnetic wave and Bloch oscillations are hybridized. There is a low-frequency branch that is unstable, whereas the high-frequency one is always stable. Instability of the low-frequency mode makes possible the creation of a tunable Bloch-oscillator-based tetrahertz (THz) amplifier and generator using microstrip line and microcavity devices. We also find that the low-frequency branch displays a negative refraction region which is associated with the backward wave excitation in a superlattice; this gives the potential possibility of the subwavelength focusing of electromagnetic radiation in THz frequency domain by means of a superlattice flat slab.
Visible quantum cutting through downconversion in KLiGdF5:Eu3+ crystals
Authors: Kodama Nobuhiro , Oishi Shinya
Published: November 2005

Visible quantum cutting through downconversion is observed for the Gd3+–Eu3+ couple in KLiGdF5:Eu3+ (KLGF:Eu3+). In this Gd3+-based fluoride, visible quantum cutting, the emission of two photons of visible light per absorbed photon, occurs upon vacuum ultraviolet excitation of Gd3+ at the GJ6 level via two-step energy transfer from Gd3+ to Eu3+ by cross relaxation and sequential transfer of the remaining excitation energy. The dependence of the efficiency of cross relaxation required for visible quantum cutting on the Eu3+ doping concentration is discussed in terms of the probability of energy transfer and the behavior of decay of the D05 emission of Eu3+, and it is found that the KLGF crystal doped with 2at.% Eu3+ exhibits the maximum cross-relaxation efficiency of 0.4. From the number of nearest neighbors around Gd3+ ions and the D05 emission intensity, energy transfer from excited Gd3+ ions is determined to extend to the fourth-nearest Eu3+ neighbors in the quantum cutting process.
Thermal stability and atomic ordering of epitaxial Heusler alloy Co2FeSi films grown on GaAs(001)
Authors: Hashimoto M. , Herfort J. , Schönherr H.-P. , Ploog K. H.
Published: November 2005

The thermal stability and the atomic ordering of single-crystal Heusler alloy Co2FeSi layers grown by molecular beam epitaxy on GaAs(001) have been studied. We found that the Co2FeSi layers have a long-range atomic order and crystallize in a partly disordered L21 structure in the low growth temperature (TG) regime. The long-range atomic order of the layers is further improved with increasing TG up to 350°C. However, the increase of TG induces an interfacial reaction between the Co2FeSi layer and the GaAs substrate. The analysis of the in-plane magnetic anisotropy reveals that the interface perfection is improved up to TG=200°C and deteriorated due to an interfacial reaction above 200°C.
Non-Gaussian dark current noise in p-type quantum-well infrared photodetectors
Authors: Paltiel Y. , Snapi N. , Zussman A. , Jung G.
Published: November 2005

Bias-dependent non-Gaussian dark current noise has been observed in p-type quantum-well infrared photodetectors. Time domain analysis of the noise revealed two-level telegraphlike fluctuations with exponentially distributed lifetimes that change dramatically with changing bias. The nature of the non-Gaussian fluctuations at intermediate voltages is ascribed to switching between two electric-field distributions corresponding to distinct tunneling probabilities out of the quantum wells. The finite transition time between the levels is identified with the recharging time.
Improved electrical and material characteristics of HfTaO gate dielectrics with high crystallization temperature
Authors: Zhang M. H. , Rhee S. J. , Kang C. Y. , Choi C. H. , Akbar M. S. , Krishnan S. A. , Lee T. , Ok I. J. , Zhu F. , Kim H. S. , Lee Jack C.
Published: November 2005

N -type metal-oxide-semiconductor field-effect transistors (N-MOSFETs) using HfTaO with varying Ta composition (20%, 30%, 40%, and 50%) have been fabricated and characterized. Crystallization temperatures of HfTaO with varying Ta composition were also measured. It was found that HfTaO with 40% Ta exhibited the highest crystallization temperature of 900 °C, while 35% and 52% HfTaO showed crystallization temperature of 800 °C. The results demonstrate that HfTaO N-MOSFETs exhibit higher electron mobility than controlled HfO2 devices. Among them, the transistor with 40% Ta shows the highest electron mobility.
Fiber Bragg grating vacuum sensors
Authors: McMillen Ben , Jewart Chuck , Buric Michael , Chen Kevin P. , Lin Yuankun , Xu Wei
Published: November 2005

This letter demonstrates functional enhancements of fiber Bragg grating sensors powered by in-fiber light. High-power laser light transmitted in double-clad optical fiber was extracted from the fiber core to heat an on-fiber metal coating. When the power-laser is turned off, the fiber Bragg grating is used as a passive component for temperature sensing. When the laser is turned on, the thermal response of the optically heated grating was used to monitor ambient air pressure. The sensitivity and dynamic range of optically powered fiber sensors can be actively adjusted by in-fiber light to measure vacuum pressures over four orders of magnitude.