bluuebunny/crossref_metadata_2025 huggingface dataset:
Technetium‐99m 2‐Methoxyisobutyl isonitrile‐scintigraphy: Preoperative and Intraoperative Guidance for Primary Hyperparathyroidism
Authors: Farley David R.
Published: November 2004

As refinement of technetium‐99m 2‐methoxyisobutyl isonitrile‐scintigraphy (MIBI)‐scintigraphy of parathyroid glands has continued since its initial use in 1989, the sensitivity, specificity, and overall accuracy of the technique have improved greatly, approaching 100% for larger, solitary adenomas. Preoperative use of sestamibi scintigraphy has become commonplace and allows surgeons the option of a minimally invasive, or focused approach for their patients with primary hyperparathyroidism. Intraoperative use of the gamma probe based on sestamibi localization has not caught on due to lesser accuracy, cumbersome gamma probes, small doses of radiation exposure for patients and staff, and the greater accuracy and current confidence in intraoperative parathormone (PTH) monitoring. However, with the potential for smaller and more accurate gamma probes that truly assist in localizing abnormal parathyroid glands, the potential for cost reduction by shortening operative times, avoiding expensive PTH assays, and eliminating the need for pathologic analysis, gamma scintigraphy may yet become a viable option for many parathyroid surgeons.
Timing and Extent of Surgery in Patients with Familial Medullary Thyroid Carcinoma/Multiple Endocrine Neoplasia 2A‐related RET Mutations Not Affecting Codon 634
Authors: Gimm Oliver , Ukkat Jörg , Niederle Barbara E. , Weber Theresa , Thanh Phuong Nguyen , Brauckhoff Michael , Niederle Bruno , Dralle Henning
Published: November 2004

In hereditary medullary thyroid carcinoma (MTC), recommendations regarding timing and extent of surgery are mainly based on the data of patients with the codon 634 RET mutation, which is the most often affected codon. Little is known about whether these recommendations may also be applied to patients with less common RET mutations. We ascertained the data from 140 patients with FMTC/MEN2A‐related RET mutation not affecting codon 634 who have been treated at three specialized centers. The several RET mutations found affected codons 611 (n = 17), 618 (n = 22), 620 (n = 17), 768 (n = 9), 790 (n = 24), 791 (n = 21), 804 (n = 23), and 891 (n = 7). For each codon, the age of the youngest patient with MTC only (41, 7, 18, 29, 13, 47, 20, and 15 years, respectively), MTC with lymph node metastases (46, 24, 21, 34, 46, 47, 50, and 76 years, respectively), and MTC with distant metastases (52, 69, 43, 68, 57, ‐, ‐, and 75 years, respectively) was determined. All patients with lymph node metastases had elevated basal calcitonin levels. Based on these data, a more individual recommendation regarding timing and extent of surgery can be given. Because neither gender nor the type of nucleotide substitution for a specific codon appeared to have a significant influence on the age of onset, this recommendation should be based on the affected codon, the age of the patient, and the calcitonin level. Recurrent laryngeal nerve palsy (n = 6) and hypoparathyroidism (n = 3) were rather rare and were found only in patients older than 30 and 43 years, respectively, giving evidence that surgery in young patients can be performed safely.
Intraoperative Parathyroid Hormone Monitoring
Authors: Inabnet William B.
Published: November 2004

The principles of minimally invasive parathyroidectomy include the successful preoperative localization of a solitary adenoma, a targeted operative approach that does not disturb the normal parathyroid glands, and intraoperative confirmation of excision of all hypersecreting parathyroid tissue. By providing real‐time feedback to the surgical team, the rapid PTH assay allows surgeons to assess the completeness of parathyroid resection without visualizing all the parathyroid glands. Intraoperative PTH monitoring facilitates the use of local anesthesia, decreases the duration of surgery, and allows ambulatory surgery in most patients. This article reviews current recommendations and controversies surrounding the use of intraoperative PTH monitoring during parathyroidectomy.
Current Concepts in Functioning Endocrine Tumors of the Pancreas
Authors: Proye Charles A.G. , Lokey Jonathan S.
Published: November 2004

Duodenal and pancreatic endocrine tumors are uncommon and their surgical treatment is often difficult. The management of these tumors has changed with recent advancements in tumor localization, intraoperative hormone measurements, standardized surgical techniques, and a better understanding of the genetic basis of multiple endocrine neoplasia syndrome. We present our experience with 191 endocrine tumors and elaborate the contemporary management of functioning duodenopancreatic endocrine tumors.
Differentiated Operative Strategy in Minimally invasive, Video‐assisted Thyroid Surgery Results in 196 Patients
Authors: Schabram Jochen , Vorländer Christian , Wahl Robert A.
Published: November 2004

To date, experience in minimally invasive thyroid surgery has been limited to unilateral lobectomy and total thyroidectomy. There are no reports regarding selective operative strategy, guided by morphology and function, which is widely accepted in endemic goiter regions. To analyze the efficiency and outcome of tissue‐preserving thyroid surgery using a minimally invasive video‐assisted technique (MIVA‐T), a total of 196 patients were operated on for thyroid nodules between February 1999 and October 2003. Concurrent primary hyperthyroidism was treated in 22 (11%) cases. Indications for operation were solitary, multiple unilateral, or bilateral nodules with a maximum diameter of 30 mm and a maximum lobe volume of 15 ml. Contraindications for minimally invasive operation were thyroid malignancy diagnosed by fine‐needle aspiration (FNA), recurrent goiter, and Hashimoto’s thyroiditis. Nodule excision was performed in 6% of these cases; subtotal lobectomy, in 6%; selective resection, in 48%; and total lobectomy, in 39%. Histological examination revealed follicular adenoma in 82%, colloid and cystic lesions in 11%, thyroiditis in 1%, and differentiated thyroid carcinoma in 6%. Conversion to open surgery was necessary in 7.7% of the patients (secondary to malignancy demonstrated on frozen section in 3% and to technical difficulties in 4.7%). Transient and permanent laryngeal nerve palsy occurred in 2.0% and 0.5% of patients, respectively. Temporary hypoparathyroidism occurred in 5.6% of patients exclusively after conversion to open total thyroidectomy or in those patients (n = 22) with additional primary hyperparathyroidism. Given a correct indication, MIVA‐T technique can be performed with low conversion and complication rates. Selective operative strategy, guided by morphology and thyroid function, with a variety of operative procedures fitting the individual situation may be performed by this minimally invasive technique.
Congenital Pulmonary Airway Malformation (Congenital Cystic Adenomatoid Malformation) with Multiple Extrapulmonary Anomalies: Autopsy Report of a Fetus at 19 Weeks of Gestation
Authors: Pham Truc T. , Benirschke Kurt , Masliah Eliezer , Stocker J. Thomas , Yi Eunhee S.
Published: November 2004

Congenital pulmonary airway malformation, or congenital cystic adenomatoid malformation, is postulated to be a disorder of pulmonary airway morphogenesis and encompasses 5 different types with distinct levels or stages of tracheobronchial development. We present a unique case of type 2 congenital pulmonary airway malformation with a previously undocumented combination of multiple extrapulmonary anomalies, featuring ipsilateral multicystic renal dysgenesis, contralateral renal agenesis, and ovarian germ cell hypoplasia, diagnosed in a 19-week gestational age fetus by autopsy. Epithelial cells comprising the pulmonary lesions were positive for thyroid transcription factor-1, surfactant protein-B, and cytokeratin-7 but negative for cytokeratin-20 immunostainings, with the pattern seen in normal terminal bronchioles. Chromosomal analysis showed a normal female karyotype, despite a high estimated risk for Down syndrome suggested by the low maternal serum α-fetoprotein level.
Expression of WT-1, Bcl-2, and CD34 by Primary Renal Spindle Cell Tumors in Children
Authors: Shao Lei , Hill D. Ashley , Perlman Elizabeth J.
Published: November 2004

The confident diagnosis of renal spindle cell tumors in children is often difficult. An immunohistochemical study of WT-1, Bcl-2, and CD34 was performed to determine their expression profiles and to assess the potential utility of these immunohistochemical markers in the differential diagnosis of 36 cases of renal spindle cell tumors of childhood. The cases included 11 stromal predominant Wilms tumors, 12 cellular mesoblastic nephromas, 9 clear cell sarcomas of the kidney (CCSK), and 4 monophasic synovial sarcomas. WT-1 was uniformly positive in primitive undifferentiated stromal Wilms tumors (6 of 6) and negative in the differentiating and differentiated stromal elements of Wilms tumors (0 of 5). WT-1 was also negative in cellular mesoblastic nephromas (0 of 12), CCSKs (0 of 12), and synovial sarcomas (0 of 4). Bcl-2 was expressed in all stromal Wilms tumors (11 of 11), all synovial sarcomas (4 of 4), some CCSKs (4 of 9), and none of the cellular mesoblastic nephromas (0 of 12). Although CD34 was absent in the tumor cells of all the tumors studied (0 of 36), CD34 immunohistochemistry nicely demonstrated the evenly distributed septal capillaries characteristic of CCSK in all 9 cases of this tumor. We conclude that a combination of WT-1 and Bcl-2 immunohistochemistry may aid in the distinction of stromal Wilms tumor, monophasic synovial sarcoma, cellular mesoblastic nephroma, and CCSK.
Discovery of the catalytic function of a putative 2‐oxoacid dehydrogenase multienzyme complex in the thermophilic archaeon Thermoplasma acidophilum
Authors: Heath Caroline , Jeffries Alex C. , Hough David W. , Danson Michael J.
Published: November 2004

Those aerobic archaea whose genomes have been sequenced possess a single 4‐gene operon that, by sequence comparisons with Bacteria and Eukarya, appears to encode the three component enzymes of a 2‐oxoacid dehydrogenase multienzyme complex. However, no catalytic activity of any such complex has ever been detected in the Archaea. In the current paper, we have cloned and expressed the first two genes of this operon from the thermophilic archaeon, Thermoplasma acidophilum. We demonstrate that the protein products form an α2β2 hetero‐tetramer possessing the decarboxylase catalytic activity characteristic of the first component enzyme of a branched‐chain 2‐oxoacid dehydrogenase multienzyme complex. This represents the first report of the catalytic function of these putative archaeal multienzyme complexes.
Catalytic RNase P RNA from Synechocystis sp. cleaves the hepatitis C virus RNA near the AUG start codon
Authors: Sabariegos Rosario , Nadal Anna , Beguiristain Nerea , Piron Maria , Gómez Jordi
Published: November 2004

Previously, we described two RNA structural motifs in the hepatitis C viral (HCV) genome that can be processed in vitro by human ribonuclease P (RNase P) enzyme [J. Biol. Chem. 277 (2002) 30606]. One of these structures is located in the internal ribosome entry site and is conserved in the related animal pestiviruses [J. Biol. Chem. 278 (2003) 26844]. Here, we tested two prokaryotic RNase P ribozymes (P RNA) against this conserved structural motif. In vitro experiments indicated that P RNA from Synechocystis sp. can specifically process the viral transcript preparations in a position close to the human RNase P cleavage site. This provides additional support for the presence of an RNA structure similar to tRNA near the AUG start codon and suggests that Synechocystis P RNA may be an active agent for HCV antigenomic interventions.
FRU (BHLH029) is required for induction of iron mobilization genes in Arabidopsis thaliana
Authors: Jakoby Marc , Wang Hong-Yu , Reidt Wim , Weisshaar Bernd , Bauer Petra
Published: November 2004

Iron mobilization responses are induced by low iron supply at transcriptional level. In tomato, the basic helix‐loop‐helix gene FER is required for induction of iron mobilization. Using molecular‐genetic techniques, we analyzed the function of BHLH029, named FRU (FER‐like regulator of iron uptake), the Arabidopsis thaliana homolog of the tomato FER gene. The FRU gene was mainly expressed in roots in a cell‐specific pattern and induced by iron deficiency. FRU mutant plants were chlorotic, and the FRU gene was found necessary for induction of the essential iron mobilization genes FRO2 (ferric chelate reductase gene) and IRT1 (iron‐regulated transporter gene). Overexpression of FRU resulted in an increase of iron mobilization responses at low iron supply. Thus, the FRU gene is a mediator in induction of iron mobilization responses in Arabidopsis, indicating that regulation of iron uptake is conserved in dicot species.
Echinacea alkylamides modulate TNF‐α gene expression via cannabinoid receptor CB2 and multiple signal transduction pathways
Authors: Gertsch Juerg , Schoop Roland , Kuenzle Urs , Suter Andy
Published: November 2004

Echinacea plant preparations are widely used in the prevention and treatment of common cold. However, so far no molecular mechanism of action has been proposed. We analyzed the standardized tincture EchinaforceTM and found that it induced de novo synthesis of tumor necrosis factor α (TNF‐α) mRNA in primary human monocytes/macrophages, but not TNF‐α protein. Moreover, LPS‐stimulated TNF‐α protein was potently inhibited in the early phase but prolonged in the late phase. A study of the main constituents of the extract showed that the alkylamides dodeca‐2E,4E,8Z,10E/Z‐tetraenoic acid isobutylamides (1/2), trienoic (3) and dienoic acid (4) derivatives are responsible for this effect. The upregulation of TNF‐α mRNA was found to be mediated by CB2 receptors, increased cAMP, p38/MAPK and JNK signaling, as well as NF‐κB and ATF‐2/CREB‐1 activation. This study is the first to report a possible molecular mechanism of action of Echinacea, highlighting the role of alkylamides as potent immunomodulators and potential ligands for CB2 receptors.
Biological validation of coenzyme Q redox state by HPLC‐EC measurement: relationship between coenzyme Q redox state and coenzyme Q content in rat tissues
Authors: Galinier A. , Carrière A. , Fernandez Y. , Bessac A.M. , Caspar-Bauguil S. , Periquet B. , Comtat M. , Thouvenot J.P. , Casteilla L.
Published: November 2004

The properties of coenzymes Q (CoQ9 and CoQ10) are closely linked to their redox state (CoQox/total CoQ) × 100. In this work, CoQ redox state was biologically validated by high performance liquid chromatography‐electrochemical measurement after modulation of mitochondrial electron flow of cultured cells by molecules increasing (rotenone, carbonyl cyanide chlorophenylhydrazone) or decreasing (antimycin) CoQ oxidation. The tissue specificity of CoQ redox state and content were investigated in control and hypoxic rats. In control rats, there was a strong negative linear regression between tissular CoQ redox state and CoQ content. Hypoxia increased CoQ9 redox state and decreased CoQ9 content in a negative linear relationship in the different tissues, except the heart and lung. This result demonstrates that, under conditions of mitochondrial impairment, CoQ redox control is tissue‐specific.
Ozone depletion caused by NO and H2O emissions from hydrazine‐fueled rockets
Authors: Ross M. N. , Danilin M. Y. , Weisenstein D. K. , Ko M. K. W.
Published: November 2004

Rockets using unsymmetrical dimethyl hydrazine (N(CH3)2NH2) and dinitrogen tetroxide (N2O4) propellants account for about one third of all stratospheric rocket engine emissions, comparable to the solid‐fueled rocket emissions. We use plume and global atmosphere models to provide the first estimate of the local and global ozone depletion caused by NO and H2O emissions from the Proton rocket, the largest hydrazine‐fueled launcher in use. NO and H2O emission indices are assumed to be 20 and 350 g/kg (propellant), respectively. Predicted maximum ozone loss in the plume of the Proton rocket is 21% at 44 km altitude. Plume ozone loss at 20 km equals 8% just after launch and steadily declines to 2% by model sunset. Predicted steady state global ozone loss from ten Proton launches annually is 1.2 × 10−4%, with nearly all of the loss due to the NO component of the emission. Normalized by stratospheric propellant consumption, the global ozone depletion efficiency of the Proton is approximately 66–90 times less than that of solid‐fueled rockets. In situ Proton plume measurements are required to validate assumed emission indices and to assess the role of rocket emissions not considered in these calculations. Such future studies would help to establish a formalism to evaluate the relative ozone depletion caused by different rocket engines using different propellants.
Volcanic plume monitoring at Mount Etna by diffusive (passive) sampling
Authors: Aiuppa A. , Bellomo S. , D'Alessandro W. , Federico C. , Ferm M. , Valenza M.
Published: November 2004

This paper reports the use of diffusive tubes in determining HF, HCl, and SO2 in the volcanic plume of Mount Etna in an attempt to highlight the potential of this method in studying volcanoes. In a first application a network of 18 diffusive tubes was installed on Etna's flanks, aimed at evaluating the atmospheric dispersion of the volcanic plume on a local scale. Results showed a monotonic decrease in volatile air concentrations with distance from the craters (HF from 0.15 to <0.003 μmol m−3, HCl from 2 to <0.01 μmol m−3, and SO2 from 11 to 0.04 μmol m−3), revealing the prevalently volcanic contribution. Matching of SO2/HCl and HCl/HF volatile ratios with contemporaneous measurements at the summit craters validated the use of diffusive tubes in tracing the chemical features of a volcanic plume from remote locations. A first tentative assessment of dry deposition rates of volcanogenic acidic gases was also made, yielding 2.5–74 t d−1 (SO2), 0.6–17 t d−1 (HCl), and 0.02–0.6 t d−1 (HF) and revealing the potential environmental impact of gas emissions. In a second experiment, carried out during the recent October 2002 to February 2003 eruption of Etna, diffusive tubes provided a continuous record of the chemical composition of the eruptive plume from a “safe” distance of ∼1 km from the vents, thus considerably decreasing the risks involved in sampling. This highlighted a clear time decrease in SO2 concentrations and SO2/HCl ratios, which was interpreted as due to progressive exhaustion of volatile degassing and eruption energy.
Drowned carbonate platforms in the Huon Gulf, Papua New Guinea
Authors: Webster Jody M. , Wallace Laura , Silver Eli , Applegate Bruce , Potts Donald , Braga Juan Carlos , Riker‐Coleman Kristin , Gallup Christina
Published: November 2004

The western Huon Gulf, Papua New Guinea, is an actively subsiding foreland basin dominated by drowned carbonate platforms. We investigated these platforms using new high‐resolution multibeam, side‐scan sonar and seismic data, combined with submersible observations and previously published radiometric and sedimentary facies data. The data reveal 14 distinct drowned carbonate platforms and numerous pinnacles/banks that increase in age (∼20–450 kyr) and depth (0.1–2.5 km) NE toward the Ramu‐Markham Trench. Superimposed on this overall downward flexing of the platforms toward the trench is a systematic tilting of the deep platforms 15 m/km toward the NW and the shallow platforms 2 m/km toward the SE. This may reflect the encroaching thrust load from the NW (Finisterre Range) and spatial variations in the flexural rigidity of the underlying basement. The drowned platforms form a complex system of promontories and reentrants, with abundant pinnacles and banks preserved at similar depths seaward of the main platforms. This configuration closely mimics the present‐day Huon coastline and its seaward islands fringed by modern coral reefs. The platforms retain structural, morphologic, and sedimentary facies evidence of primary platform growth, drowning, and subsequent backstepping, despite some lateral erosion of the platform margins (<100 m slope defacement) by mass wasting. Both platforms and pinnacles are composite features containing multiple terrace levels and notches, corresponding to multiple phases of growth, emergence, and drowning in response to rapid climatic and sea level changes during the evolution of each structure. On the basis of all observational and numerical modeling data, we propose a chronology for the initiation, growth, and drowning of the 14 platforms. Over shorter timescales (≤100 kyr) the rate and amplitude of eustatic sea level changes are critical in controlling initiation, growth, drowning or subaerial exposure, subsequent reinitiation, and final drowning of the platforms. However, continued tectonic subsidence and basement substrate morphology influence the overall backstepping geometry and subsequent tilting of the platforms over longer timescales (≥100–500 kyr).
Oblique rifting and segmentation of the NE Gulf of Aden passive margin
Authors: Fournier Marc , Bellahsen Nicolas , Fabbri Olivier , Gunnell Yanni
Published: November 2004

The Gulf of Aden is a young, obliquely opening, oceanic basin where tectonic structures can easily be followed and correlated from the passive margins to the active mid‐oceanic ridge. It is an ideal laboratory for studies of continental lithosphere breakup from rifting to spreading. The northeastern margin of the Gulf of Aden offers the opportunity to study on land the deformation associated with oblique rifting over a wide area encompassing two segments of the passive margin, on either side of the Socotra fracture zone, exhibiting distinct morphologic, stratigraphic, and structural features. The western segment is characterized by an elevated rift shoulder and large grabens filled with thick synrift series, whereas the eastern segment exhibits low elevation and is devoid of major extensional structures and typical synrift deposits. Though the morphostructural features of the margin segments are different, the stress field analysis provides coherent results all along the margin. Four directions of extension have been recognized and are considered to be representative of two tensional stress fields with permutations of the horizontal principal stresses σ2 and σ3. The two dominant directions of extension, N150°E and N20°E, are perpendicular to the mean trend of the Gulf of Aden (N75°E) and parallel to its opening direction (N20°E–N30°E), respectively. Unlike another study in the western part of the gulf, our data suggest that the N150°E extension stage is older than the N20°E extension stage. These conflicting chronologies, which are nowhere unambiguously established, suggest that the two extensions coexisted during the rifting. On‐land data are compared with offshore data and are interpreted with reference to oblique rifting. The passive margin segmentation represents a local accommodation of the extensional deformation in a homogeneous regional stress field, which reveals the asymmetry of the rifting process. The first‐order segmentation of the Sheba Ridge is inherited from the prior segmentation of the passive margin.
Tropical origins for recent and future Northern Hemisphere climate change
Authors: Selten Frank M. , Branstator Grant W. , Dijkstra Henk A. , Kliphuis Michael
Published: November 2004

Results from a large ensemble of climate model simulations over the period 1940–2080 suggest that the observed strengthening of the westerly winds over the North Atlantic during the past decades is not due to the enhanced greenhouse effect but is largely an expression of a random, internal climate variation driven by increased precipitation over the tropical Indian Ocean. Instead, the enhanced greenhouse effect drives a change in the extra‐tropical winter circulation through intensified precipitation over the tropical West Pacific. This change is characterized by a wave train encompassing the whole Northern hemisphere, a pattern known as the Circumglobal Waveguide Pattern.
Derivation and validation of photolysis rates of O3, NO2, and CH2O from a GUV‐541 radiometer
Authors: Seroji Abdulaziz R. , Webb Ann R. , Coe Hugh , Monks Paul S. , Rickard Andrew R.
Published: November 2004

Solar UV radiation plays a very significant role in terms of atmospheric chemistry. The UV radiation that reaches the troposphere drives the photodissociation of tropospheric species whose photolysis energies fall in the range of these wavelengths. The relevant measure of radiation for atmospheric chemistry is actinic flux, but the great majority of UV measurements, not common in themselves, are UV irradiance (radiation on a flat surface). Spectral UV irradiance was measured in Manchester, UK (78 m altitude, 53.28°N, 2.14°W) using a moderate bandwidth filter radiometer (GUV‐541) that has five channels in the UV region with center wavelengths at 305, 313, 320, 340, and 380 nm and band‐pass functions of approximately 10 nm. This study describes a new method of deriving the photolysis rate of O3, NO2, and CH2O utilizing the GUV irradiance measurements. The measured irradiance was compared with independently measured photolysis rates determined from the actinic flux measured by a Bentham spectroradiometer on a clear sky day. On the reference day, a linear regression of GUV global irradiance to simultaneous photolysis rate measurements was performed to generate scale factors for each optical channel. The results compare favorably with the general uncertainty in photolysis measurements of about 20%. A further separate comparison is made with comparable filter radiometers.
Contribution of regional pollution and long‐range transport to the Asia‐Pacific region: Analysis of long‐term ozonesonde data over Japan
Authors: Naja Manish , Akimoto Hajime
Published: November 2004

Long‐term (1970–2002) ozonesonde data from four sites in Japan (Sapporo, Tsukuba, Kagoshima, and Naha) have been analyzed using a sectoral air mass classification based on back air trajectories. Air masses from “regionally polluted,” “Eurasia,” Pacific, and Japan regions are tagged with daily ozone values at each of the four sites. Ozone in regionally polluted air masses shows a broad maximum in spring and summer and a minimum in winter, whereas ozone in other air masses shows a maximum in spring and minimum in summer at Tsukuba, Kagoshima, and Naha. The wintertime ozone in regionally polluted air masses is highest but summertime ozone is lowest at Naha among all other sites. In the lower troposphere the air masses from southern China also show much lower ozone levels in summer than from the northern part (up to 36 ppbv in August), which is suggested to be due to the additional influence of an Asian monsoon over southern China. Ozone levels at Sapporo are determined mainly by Eurasian air masses and show a broad maximum in spring and summer. The boundary layer ozone levels in the regionally polluted air masses are 10–12 ppbv higher throughout the year than in the Eurasian air masses, and in winter they are about 8 ppbv higher than over Europe. However, ozone levels and seasonal variations are similar over Japan and Europe in the lower troposphere. Ozone levels in the regionally polluted air masses increased by 11–20% (5–11 ppbv) from 1970s to 1990s over Japan, and this is attributed to the large increase in NOx emissions over China in the 1990s. The long‐term trend (between 1970 and 1990) in regionally polluted ozone is observed not to be very different over Japan and Europe, particularly in the lower troposphere. However, during the 1990s the wintertime positive trend (0.2–0.4 ppbv yr−1) in lower tropospheric ozone in the Eurasian air masses at Sapporo is suggested to be due to the intercontinental transport from Europe/North America. However, the inconsistency between the long‐term trend in the regionally polluted ozone and the NOx emissions over China in the 1990s remains unexplained.
Purification and enzymatic activity of an NADH‐fumarate reductase and other mitochondrial activities of Leishmania parasites
Authors: CHEN M. , BENNEDSEN M. , ZHAI L. , KHARAZMI A.
Published: November 2004

A 65 kD membrane‐associated NADH‐fumarate reductase subunit, which has a molecular weight similar to that of one of the enzyme subunits from bacteria, was purified from Leishmania donovani promastigotes. NADH‐fumarate reductase and other mitochondrial enzymatic activities of L. major and L. donovani promastigotes and amastigotes were investigated. The presence of NADH‐fumarate reductase was demonstrated in digitonin‐permeabilized L. major promastigotes and mitochondria of L. major and L. donovani promastigotes and amastigotes. The activity of solubilized NADH‐fumarate reductase was measured in L. major and L. donovani promastigotes. Succinate exhibited a clear concentration‐dependent inhibitory effect on fumarate reductase, whereas fumarate also exhibited a clear concentration‐dependent inhibitory effect on succinate dehydrogenase. The data indicate that fumarate reductase is an obligatory component of the respiratory chain of the parasite. Since the enzyme is an important component in the intermediate metabolism in the Leishmania parasite and is absent in mammalian cells, it could be a potential target for antileishmanial drugs.
Age‐ and sex‐related differences in antibody responses against Schistosoma mansoni soluble egg antigen in a cohort of school children in Ethiopia
Authors: ABEBE F. , GAARDER P. I. , PETROS B. , GUNDERSEN S. G.
Published: November 2004

Acquired immunity is believed to be the main factor in the age‐related differences in prevalence and intensity of Schistosoma infections. We studied antibody responses against S. mansoni soluble egg antigen (SEA) by ELISA in children before treatment, 5 weeks and one year after treatment. After screening for S. mansoni infection, positive children were treated with praziquantel (40 mg per kg body weight). Infection rate was significantly higher in boys younger than 12 years than in girls in the same age group. Levels of all antibody isotypes, except IgG1 (before treatment) or IgA (one year after treatment), were higher in children older or equal to 12 years than in those younger. The difference between age groups was significant for IgE, IgM, IgG3 and IgG4 (before treatment) and IgE (one year after treatment). Similarly, all antibody isotypes, except IgE, before treatment were higher in boys than in girls. At 5 weeks after treatment, IgG, IgE and IgG1 showed an increasing tendency, whereas IgM and IgG3 tended to decrease. One year after treatment, significant decreases were observed in IgG, IgG1 and IgG4 and a significant increase in IgG2 levels. The study presents further evidence for the difference in acquired immunity between younger and older children, and between boys and girls. The study also suggests that praziquantel differentially affects antibody responses against S. mansoni SEA.
Complement deposition in renal allografts with early malfunction
Authors: EGGERTSEN GÖSTA , NYBERG GUDRUN , NILSSON BO , NILSSON ULF , SVALANDER CHRISTIAN T.
Published: November 2004

Among patients with early severe impairment of renal allograft function we have previously identified a group displaying isolated deposition of complement factor C3 in glomeruli. Here we studied the pattern of complement deposition more extensively in allograft biopsies from five patients using an immunofluorescence technique. We found a prominent deposition of C3c, C3d and C4d antigens in the glomerular capillary walls, and a positive reaction to vitronectin (S‐protein), but only trace amounts of the complement factor C9 neoepitope. Clq, C4c, C3a, iC3b, factor B, properdin, immunoglobulins IgG, IgA or IgM were not found in glomeruli or in any other cortical structure. These findings indicate that most of the demonstrated glomerular C3 consists of C3b and/or C3c/C3d molecules. By immunoelectron microscopy the C3 antigen was found within the glomerular basement membrane. Our findings indicate that there is a mechanism of complement activation involving the early steps of the classical pathway, despite the lack of demonstrable immunoglobulins in the tissue. In analogy with similar reactions described recently in heart allografts, we suggest that this may be a manifestation of a humoral rejection, possibly mediated by a low titer of circulating antibodies directed against endothelial surface antigens, presumed to be the initial step leading to complement activation.
Helicobacter pylori antibodies and gastric cancer in Iceland – The decline in IgG antibody level is a risk factor
Authors: TULINIUS H. , ÖGMUNDSDOTTIR H. M. , KRISTINSSON K. G. , SIGVALDASON H. , SIGVALDADOTTIR E. , KRISTJANSDOTTIR G. , SIGFUSSON N.
Published: November 2004

H. pylori infection is considered a causal agent of duodenal ulcer and a significant risk factor for gastric cancer. Retrospective cohort studies have demonstrated a significant association between presence of antibody to H. pylori and gastric cancer when using samples obtained years before the diagnosis but not at the time of diagnosis. The present study investigates, in a population‐based cohort, whether a decline occurs in H. pylori antibody levels before the diagnosis of stomach cancer. Repeat samples (2 to 5) were available from 23 persons with gastric cancer taken up to 20 years before the diagnosis and 128 control subjects matched for gender, age, time and number of repeat samples. The odds ratio of developing stomach cancer was 1.16 (95% CI 1.05–1.28) for those showing decline in antibody levels of 1 relative antibody activity unit per year versus those with constant or rising levels. We conclude that this decline in antibody levels in cases, and not in controls, supports an active role of H. pylori in the pathogenesis of gastric cancer by causing atrophic gastritis, and provides a better risk assessment for gastric cancer compared to single measurements.
Study of the interaction of tris-(8-hydroxyquinoline) aluminum (Alq3) with potassium using vibrational spectroscopy: Examination of possible isomerization upon K doping
Authors: Sakurai Y. , Hosoi Y. , Ishii H. , Ouchi Y. , Salvan G. , Kobitski A. , Kampen T. U. , Zahn D. R. T. , Seki K.
Published: November 2004

The geometrical structure of potassium-doped Alq3 [tris-(8-hydroxyquinoline) aluminum] and the interaction between the Alq3 molecule and potassium were studied using infrared reflection absorption spectroscopy (IRRAS), surface-enhanced Raman scattering (SERS), and density functional theory calculations. A major aim of this study was to examine the theoretically predicted isomerization of Alq3 molecules from the meridional form to the facial form upon alkali-metal doping. The observed spectra show significant changes with the deposition of potassium on a thin Alq3 film. The calculated IR spectra of the K-Alq3 complex differ significantly between the meridional and facial forms, and the calculation for the meridional form agrees fairly well with the observed spectrum. This demonstrates that (1) the Alq3 molecule does not change to a facial isomer with the deposition of potassium, but retains the meridional form, in contrast to the reported theoretical prediction, and (2) the structure of the complex as evaluated from geometry optimization is reliable. We also found that the calculated IR spectrum of the K-Alq3 complex with Alq3 in its meridional form is significantly different from that of the isolated anion in the same isomeric form, which probably reflects nonuniform interaction between K and the three ligands of Alq3. On the other hand, the calculated spectra of Alq3 and the K-Alq3 complex in the facial form are similar, possibly because the K atom in the suggested structure lies on the axis of threefold symmetry, leading to an equivalent effect on the three ligands. Even though vibrational spectra of alkali-metal-doped organic materials are usually interpreted on the basis of an isolated anion, the results presented here show that care should be taken in interpreting the spectra of doped organic materials without considering the presence of the counter ion. The observed SERS spectra and theoretical calculations of the Raman spectra show similar trends when compared to the IRRAS results. The present results show that vibrational spectroscopy can be used as a sensitive tool for discerning subtle differences between isomers as well as between complexes and isolated anions.
Characteristics of Ba(Mg1∕3Ta2∕3)O3 thin films prepared by pulsed laser deposition process and their effect on the growth of Pb(Zr1−xTix)O3 thin films
Authors: Lin I-Nan , Liang Chen-Wei , Chu Ying-Hao , Lin Su-Jien
Published: November 2004

The growth behavior of Ba(Mg1∕3Ta2∕3)O3 (BMT) thin films on bare or Pt-coated silicon substrates and their buffering effect on the subsequently deposited Pb(Zr,Ti)O3 (PZT) films were systematically examined. The preferred orientation of BMT layer varies pronouncedly with the deposition parameters. It is (200) textured when deposited under high substrate temperature (400°C) or large laser fluence (3J∕cm2). The BMT layer not only suppresses the film-to-substrate interdiffusion but also enhances the Pb(Zr1−xTix)O3 (PZT) nucleation kinetics. The PZT films prepared on BMT layer by metal-organic-decomposition (MOD) process begin to crystallize at a substrate temperature as low as 400°C, which is lower than the reported heat treatment temperature for preparing PZT films via MOD process. However, postannealing at 550°C is required to fully crystallize the PZT films. The PZT∕BMT∕Pt(Si) thin films show high dielectric constant [(ϵr)PZT=400–425], low leakage current density (Je<2×10−7A∕cm2), and good ferroelectric properties (Pr=15μC∕cm2, Ec=157kV∕cm), while the PZT∕BMT∕Si thin films exhibit a large optical refractive index (nPZT∕BMT∕Si=2.4).
Constructal heat trees at micro and nanoscales
Authors: Gosselin Louis , Bejan Adrian
Published: November 2004

We consider the problem of cooling a two-dimensional heat generating conducting volume with one heat sink, such that the smallest features of the internal structure are so small that the conventional description of conduction breaks down. The effective thermal conductivity exhibits the “size effect,” and is governed by the smallest structural dimension, which is comparable with the mean free path of the energy carriers. According to the constructal method, the development of the internal cooling structure proceeds from small to large, in steps of geometric optimization and assembly. This starts at the elemental level, where there is only one high-conductivity layer for collecting and evacuating the heat. The shape of the smallest volume can be optimized for minimal thermal resistance. Next, a first construct is formed by optimizing the number of assembled elements and the internal geometric features of the assembly. The method is repeated at the second construct level, where several first constructs are grouped so that their global thermal resistance is minimal. The construction reveals an internal multiscale structure shaped as a tree, where the spaces between the smallest branches are ruled by nanoscale heat transfer. It is shown that the transition from regions with nanoscale heat transfer to regions with conventional heat transfer is governed not only by the smallest dimensions, but also by heterogeneity (relative amounts of high- and low-conductivity materials).
Electric and thermoelectric properties of electrodeposited bismuth telluride (Bi2Te3) films
Authors: Takahashi Makoto , Kojima Masashi , Sato Shoji , Ohnisi Naoyuki , Nishiwaki Akira , Wakita Koichi , Miyuki Takuma , Ikeda Shoichiro , Muramatsu Yasuhiko
Published: November 2004

We investigated the relationships among the deposition potential, the electric properties, and the thermoelectric properties of Bi2Te3 films electrodeposited from a solution containing 1.00mM TeO2 and 0.86mM Bi-EDTA complex. From the results of the Hall-effect measurements, the films formed at >−0.27V vs Ag∕AgCl were Te-rich n-Bi2Te3, and the carrier concentration increased with more negative deposition potential. The films formed at <−0.35V were Bi-rich p-Bi2Te3, and the carrier concentration showed a constant value. A depth profile showed that all the electrodeposited films were composed of two layers, and that an n-type layer containing a large excess of Te existed near the substrate surface. From the Seebeck coefficient measurements, the electrical type of all the films was n type, and the maximum Seebeck coefficient (−70±10μVK−1) was observed for the film deposited at −0.20V. The electrical type obtained by the Seebeck coefficient measurements was completely different from the electrical type determined by the Hall-effect measurements. This difference could be explained by the p-n junction formation near the substrate surface.
Electrical properties of metal-ferroelectric-insulator-semiconductor structures based on ferroelectric polyvinylidene fluoride copolymer film gate for nonvolatile random access memory application
Authors: Lim S. H. , Rastogi A. C. , Desu S. B.
Published: November 2004

Metal-ferroelectric–insulator-semiconductor device structures with ferroelectric vinylidene fluoride-trifluoroethylene copolymer and SiO2 buffer layer integrated gate stack over n-Si are formed, and their potential for fabricating polymeric nonvolatile random access memory devices is demonstrated. Capacitance-voltage (C–V) studies show that switchable polarization in poled polyvinylidene fluoride PVDF copolymer film changes the Si-surface potential and causes modulation of the Si-surface conductance. The (C–V) hysteresis and bidirectional flatband voltage shift at −10 to +6V, depending on the polarization field direction and remnant polarization at the ferroelectric PVDF copolymer gate, presents a memory window. The space charge at n-Si and switchable polarization both reduce the field across the ferroelectric PVDF. The observed asymmetry of the negative flatband-voltage shifts in the negatively poled ferroelectric polymer state is the result of the depletion layer formation, which reduces the field across the polymeric gate. Internal field due to negative and positive bound charges within PVDF copolymer and SiO2, respectively, influences polarization switching by pinning of dipoles. Higher negative gate bias is needed to overcome the pinning effect and to switch the polarization field. @2004 American institute of Physics.
Polarization loop deformations of an oxygen deficient Pb(Zr0.25,Ti0.75)O3 ferroelectric thin film
Authors: Le Rhun G. , Bouregba R. , Poullain G.
Published: November 2004

An epitaxial oxygen deficient Pb(Zr0.25,Ti0.75)O3 (PZT) thin film, which presented hysteresis loop with significant shift along the electric field axis and apparent polarization suppression, is investigated. Loop deformations are studied and entirely explained, both qualitatively and quantitatively by simulations including the effect of an ultrathin interfacial layer uniformly charged. The method developed in this paper is suitable to calculate not only the polarization due to the switching domains, but also all the characteristics of the space charge layer. The determination of the linear dielectric constant of the bulk ferroelectric layer does not require preparation of films with different thicknesses, unlike most of the methods proposed to date. Linear dielectric constant and thickness of the interfacial layer are in the range εil=80–130 and dil=8–12nm, respectively. On the other hand, a very large interfacial charge concentration (Nil of few 1026m−3) is obtained. For the studied PZT sample, hysteresis deformations are not attributable to pinning of domain walls, despite the large value of Nil, but rather to the interfacial space charge layer that screens the applied electric field and prevents the full switching of the ferroelectric domains.
Interfacial roughening during solid phase epitaxy: Interaction of dopant, stress, and anisotropy effects
Authors: Barvosa-Carter William , Aziz Michael J. , Phan A.-V. , Kaplan T. , Gray L. J.
Published: November 2004

The effects of externally applied stress and rate-enhancing dopants on interfacial roughness during the solid phase epitaxial growth of ion-implantation-doped Si are investigated using cross-sectional transmission electron microscopy and time-resolved reflectivity. We find long-wavelength roughness in the absence of an applied stress that arises solely from the dopant-gradient. With the addition of a compressive stress, the interface roughens further with an enhanced magnitude and a dramatically reduced wavelength. We discuss the experimental results in the context of a simulation that includes our current understanding of stress, dopant-gradient, and interface anisotropy effects. We find a rich interplay between these effects in determining growth morphology evolution, and demonstrate the successes and current limitations of the model.
Structural and electrical characterization of AuPdAlTi ohmic contacts to AlGaN∕GaN with varying Ti content
Authors: Fay M. W. , Moldovan G. , Weston N. J. , Brown P. D. , Harrison I. , Hilton K. P. , Masterton A. , Wallis D. , Balmer R. S. , Uren M. J. , Martin T.
Published: November 2004

Au Pd Al Ti ∕ Al Ga N ∕ Ga N ohmic contact structures with varying Ti:Al ratios have been investigated. The relationship between Ti:Al ratio, interfacial microstructure, and contact resistance is examined. Rapid thermal annealing temperatures of 850°C or higher are required to produce an ohmic contact with annealing at 950°C producing the lowest contact resistance in the majority of samples. Samples annealed at 950°C have been analyzed using complementary transmission electron microscopy and electrical characterization techniques. A thin Ti-nitride region is found to form at the contact/semiconductor interface in all samples. Ti-nitride inclusions through the AlGaN∕GaN layer are also observed, surrounded by an Al∕Au rich metallurgical barrier layer, with the size of the inclusions increasing with Ti content. The size of these inclusions does not have any clear effect on the electrical characteristics of the contacts at room temperature, but samples with fewer inclusions show superior electrical characteristics at high temperatures.
Defect levels and types of point defects in high-purity and vanadium-doped semi-insulating 4H–SiC
Authors: Zvanut M. E. , Konovalov V. V. , Wang Haiyan , Mitchel W. C. , Mitchell W. D. , Landis G.
Published: November 2004

Electron paramagnetic resonance (EPR) spectroscopy and photo-induced EPR are used to examine the point defects in vanadium-doped 4H–SiC and high-purity semi-insulating (HPSI) 4H–SiC grown by physical vapor transport. Both types of samples often exhibit a 1.1-eV activation energy, Ea, as extracted from the temperature-dependent Hall/resistivity measurements; however, different defects are related to the same Ea in each case. In the vanadium-doped wafers, the EPR data reveal both V4+ and V3+ in the same sample; thus, the 1.1-eV Hall activation energy is tentatively interpreted as the V3+∕4+ acceptor level. However, this conclusion cannot be confirmed because additional defects complicate the photoresponse of vanadium. The carbon vacancy, which is detected in all the HPSI wafers, exhibits a range of photothresholds similar to the various values measured for Ea. The photo-EPR and temperature-dependent Hall/resistivity measurements made before and after a 1600°C anneal suggest that several different types of nonuniformly distributed defects participate in compensation of the HPSI material and that annealing selectively removes those with different defect levels.