bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative evaluation and intercomparison of morning and afternoon Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol measurements from Terra and Aqua
Authors: Ichoku Charles , Remer Lorraine A. , Eck Thomas F.
Published: February 2005

The quality of the aerosol optical thickness (AOT) data retrieved operationally from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors aboard the Terra and Aqua satellites, over land, and over ocean from 2000 to 2003 (Aqua only from June 2002) were evaluated thoroughly. Terra‐MODIS versions 3 and 4 data (T003 and T004) and Aqua‐MODIS version 3 data (A003) were independently and comparatively evaluated with collocated AOT from ground‐based Aerosol Robotic Network (AERONET) Sun photometers. At 550 nm wavelength, 67.3%, 55.0%, and 55.5% of AOT from T003, T004, and A003, respectively, meet the prespecified accuracy conditions of ±(0.05 + 0.2aot) over land, while about 63.3%, 59.4%, and 62.2% fall within the more stringent range of ±(0.03 + 0.05aot) over ocean. However, when based on equal standards of comparison and regression analysis, aerosol retrievals are much more accurate over ocean than over land. Analysis of MODIS full regional AOT averages from 12 land and 6 oceanic regions shows that aerosol loading exhibits an annual cycle in almost every region, with the exception of very remote oceanic regions such as the central Pacific. On the basis of regional monthly averages, west Africa, China, and India show the highest peak monthly mean AOT value of ∼0.7 at 550 nm, while the highest over‐ocean aerosol loading occurs over the Mediterranean and Mid‐Atlantic oceans, with a regional monthly peak of ∼0.35, which is half of the peak over land. The magnitude of day‐to‐day variation between morning (Terra) and afternoon (Aqua) AOT varies from region to region and increases with aerosol loading for any given region. However, none of the regions examined show any consistent regional trend in morning‐to‐afternoon aerosol loading, all showing almost equal likelihood of increase or decrease from morning to afternoon.
Impact of agricultural practice on regional climate in a coupled land surface mesoscale model
Authors: Cooley H. S. , Riley W. J. , Torn M. S. , He Y.
Published: February 2005

The land surface has been shown to form strong feedbacks with climate due to linkages between atmospheric conditions and terrestrial ecosystem exchanges of energy, momentum, water, and trace gases. Although often ignored in modeling studies, land management itself may form significant feedbacks. Because crops are harvested earlier under drier conditions, regional air temperature, precipitation, and soil moisture, for example, affect harvest timing, particularly of rain‐fed crops. This removal of vegetation alters the land surface characteristics and may, in turn, affect regional climate. We applied a coupled climate model (MM5) and land surface model (LSM1) to examine the effects of early and late winter wheat harvest on regional climate in the Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility in the Southern Great Plains, where winter wheat accounts for 20% of the land area. Within the harvested, winter wheat region, simulated 2 m air temperature was 1.3°C warmer in the early harvest scenario at midday averaged over the 2 weeks following harvest. Soils in the harvested area were drier and warmer in the top 10 cm and wetter in the 10–20 cm layer compared to those in the late harvest. Midday soils were 2.5°C warmer in the harvested area at midday averaged over the 2 weeks following harvest. Harvest also dramatically altered latent and sensible heat fluxes. Although differences between scenarios diminished once both scenarios were harvested, the short‐term impacts of land management on climate were comparable to those from land cover change demonstrated in other studies.
Structure and changing dynamics of a polythermal valley glacier on a centennial timescale: Midre Lovénbreen, Svalbard
Authors: Hambrey Michael J. , Murray Tavi , Glasser Neil F. , Hubbard Alun , Hubbard Bryn , Stuart Graham , Hansen Siri , Kohler Jack
Published: February 2005

Most polythermal glaciers in Svalbard, other than those of surge type, have receded steadily since the early 20th century. Midre Lovénbreen, a slow‐moving, 4‐km‐long valley glacier terminating on land, is a typical example, and its internal structures reflect changing dynamics over this period. The three‐dimensional structural style of this glacier and the sequential development of structures have been determined from surface mapping, ground‐penetrating radar, and numerical flow modeling. In order of formation the structures observed today at the glacier surface are (1) primary stratification that has become folded about flow‐parallel axes; (2) axial plane longitudinal foliation associated with this folding; (3) several sets of intersecting crevasse traces; (4) arcuate upglacier‐dipping fractures developed as part of a thrust complex near the snout; and (5) longitudinal splaying fractures in the snout area. The long‐term evolution and dynamic significance of these structures can be ascertained from historical ground and aerial photographs. Modeling indicates that stratification and foliation continue to evolve today as a result of internal deformation, especially in zones of converging flow, where simple shear is most pronounced, but within the tongue are carried passively toward the snout. Crevasse traces appear to be no longer actively forming but are interpreted as relict structures when the ice was more dynamic and mostly wet based. The interpretation of arcuate fractures near the snout as thrusts is supported by the matching orientations of modeled strain ellipses, which illustrate the importance of longitudinal compression.
Numerical evaluation of a second‐order water transfer term for variably saturated dual‐permeability models
Authors: Köhne J. Maximilian , Mohanty Binayak P. , Simunek Jirka , Gerke Horst H.
Published: February 2005

Dual‐permeability models contain a lumped mass transfer term that couples equations for water flow in the soil matrix and fracture systems. Linear first‐order transfer terms cannot accurately calculate water transfer between the domains during early times of pressure head nonequilibrium. In this study, a second‐order equation for water transfer into spherical rock matrix blocks [Zimmerman et al., 1993, 1996] was adapted and evaluated comprehensively for water transfer into and out of variably saturated soil matrix blocks of different hydraulic properties, geometries, and sizes, for different initial and boundary conditions. Numerical solutions of the second‐order term were compared with respective results obtained with a first‐order term and a one‐dimensional horizontal flow equation. Accurate results were obtained after implementing two modifications in the second‐order term. First, the hydraulic conductivity was calculated as a weighted arithmetic average of conductivities that used pressure heads in matrix and fracture. For a time‐variable pressure head boundary condition, a fixed weighting factor of 17 could be applied irrespective of texture, initial condition, and matrix block size up to 10 cm. Second, if direction of water transfer changed (to or from matrix), the initial pressure head was reset to the equilibrium pressure head at the time of transfer reversal. The modified second‐order term was implemented into a dual‐permeability model, which closely approximated reference results obtained with a two‐dimensional flow model. For rectangular slab‐type or comparable geometry of soil matrix, the modified second‐order term considerably improves the accuracy of dual‐permeability models to simulate variably saturated preferential flow in soil.
Induction of Bile Acid Synthesis by Cholesterol and Cholestyramine Feeding Is Unimpaired in Mice Deficient in Apolipoprotein Ai
Authors: Jolley Christopher D. , Dietschy John M. , Turley Stephen D.
Published: February 2005

High density lipoprotein (HDL) cholesterol is believed to be preferentially utilized for bile acid synthesis and biliary secretion. In mice, the deletion of apolipoprotein AI (apo AI), the major apolipoprotein in HDL, results in very low plasma HDL–cholesterol levels. This article describes bile acid metabolism in apo AI–deficient (Apo AI-/-) mice and their C57BL/6 (Apo AI+/+) controls fed either a basal rodent diet alone or containing cholesterol or cholestyramine. Basal plasma HDL–cholesterol levels in the -/- mice (< 10 mg/dL) were less than 20% of those in their +/+ controls, but there were no phenotypic differences in either the relative cholesterol content of gallbladder bile, bile acid pool size and composition, fecal bile acid excretion or the activity of, or mRNA level for, cholesterol 7α–hydroxylase. However, compared with their +/+ controls, the -/- mice absorbed more cholesterol (33 vs. 24%) and manifested lower rates of hepatic sterol synthesis (534 vs. 1,019 nmol/h per g). Cholesterol feeding increased hepatic cholesterol levels in the +/+ animals from 2.7 to 4.4 mg/g and in the -/- mice from 2.6 to 8.1 mg/g. Bile acid synthesis increased 70% in both genotypes. Cholestyramine feeding stimulated bile acid synthesis 3.7 fold in both -/- and +/+ mice. We conclude that the virtual loss of HDL–cholesterol from the circulation in apo AI deficiency has no impact on the ability of the hepatocyte to adapt its rate of bile acid synthesis in concert with the amount of cholesterol and bile acid returning to the liver from the small intestine.
Retroviral Gene Transfer of Signaling Molecules Into Murine Fetal Hepatocytes Defines Distinct Roles for the Stat3 and Ras Pathways During Hepatic Development
Authors: Ito Yoshiaki , Matsui Takaaki , Kamiya Akihide , Kinoshita Taisei , Miyajima Atsushi
Published: February 2005

We recently demonstrated that oncostatin M (OSM) in the presence of glucocorticoid promotes development of fetal hepatic cells in a primary culture system. Our results also suggested that OSM transduces differentiation signals through gp130, a common subunit of the interleukin (IL)–6 family cytokine receptors. However, an essential downstream pathway required for hepatic development remains unknown. To address this issue, we expressed signal molecules by a retroviral expression vector in primary fetal hepatic cells and investigated a signaling pathway essential for OSM–mediated hepatic development. Expression of a dominant–negative form of STAT3 (ΔSTAT3), but not ΔSTAT5, suppressed differentiated phenotypes of hepatocytes induced by OSM. On the other hand, dominant–negative forms of Ras (RasN17) and SHP–2(C463A) rather augmented the expression of hepatic differentiation markers, suggesting that the Ras pathway negatively regulates hepatic development. Consistently, expression of a constitutively activated form of Ras (RasV12) inhibited cellular responses to OSM. Our results indicate that STAT3 is an essential signaling component for OSM–induced hepatic development, while activation of Ras appears to negatively regulate this process. Thus, retrovirus–mediated gene transfer is an effective means to analyze function of a gene in primary fetal hepatic culture.
The Promoter of the Long Variant of Collagen Xviii, the Precursor of Endostatin, Contains Liver–Specific Regulatory Elements
Authors: Liétard Jocelyne , Théret Nathalie , Rehn Marko , Musso Orlando , Dargère Delphine , Pihlajaniemi Taina , Clément Bruno
Published: February 2005

The endostatin precursor collagen XVIII is expressed at high levels in human livers, the main source being hepatocytes. We have studied the regulatory elements in the promoter 2 of the Col18a1 gene that directs the transcription of the NC1–517 variant of collagen α1(XVIII), which is the main form expressed in the liver. The 5′–flanking region of Col18a1 gene was cloned, and a series of 5′–deletions from -3286 bp to + 285 bp were linked to the luciferase reporter gene. Transfection experiments in HepG2 cells allowed to identify a silencer–like element containing putative HNF1 and HNF3 sites and activator elements containing stretches of GC–rich sequences. Another putative HNF3 site in close apposition to a NF1/CTF site was localized upstream of the silencer–like element. Cotransfection experiments showed that the Col18a1 promoter 2 was transactivated by Sp1 and HNF3α. Gel–shift analyses showed that HNF3, NF1/CTF, and Sp1–like sites specifically recognized nuclear factors. Super–shift experiments indicated that HNF3β was the major form of HNF3 interacting with the HNF3/NF1 site. The well–differentiated hepatoma cell line mhATFS315 transfected with a truncated form of HNF3β, which competitively blocks HNF3 transactivating activity, expressed the Col18a1gene at a very low level. Taken together, these data strongly suggest that Col18a1 is a liver–specific gene. Furthermore, gel–shift analyses performed with nuclear factors prepared from well–differentiated hepatocellular carcinomas showed increased HNF3/NF1 binding activity compared with normal livers. Consequently, the precursor of endostatin might be differently expressed according to the differentiated and/or transformed state of hepatocytes.
A Missense Mutation In Fic1 Is Associated With Greenland Familial Cholestasis
Authors: Klomp Leo W.J. , Bull Laura N. , Knisely Alexander S. , van der Doelen Marjolein A.M. , Juijn Jenneke A. , Berger Ruud , Forget Sylviane , Nielsen Inge-Merete , Eiberg Hans , Houwen Roderick H.J.
Published: February 2005

Greenland familial cholestasis is a severe form of intrahepatic cholestasis described among indigenous Inuit families in Greenland. Patients present with jaundice, pruritus, bleeding episodes, and steatorrhea, and die in childhood due to end–stage liver disease. We investigated the possibility that Greenland familial cholestasis is caused by a mutation in FIC1, the gene defective in patients with progressive familial intrahepatic cholestasis type 1 and many cases of benign recurrent intrahepatic cholestasis. Using single–strand conformation polymorphism analysis and sequencing of the FIC1 exons, a missense mutation, 1660 G→A (D554N), was detected and was shown to segregate with the disease in Inuit patients from Greenland and Canada. Examination of liver specimens from 3 Inuit patients homozygous for this mutation revealed bland canalicular cholestasis and, on transmission electron microscopy, coarsely granular Byler bile, as previously described in patients with progressive familial intrahepatic cholestasis type 1. These data establish Greenland familial cholestasis as a form of progressive familial intrahepatic cholestasis type 1 and further underscore the importance of unimpeded FIC1 activity for normal bile formation.
Design of A Temporally and Spatially Controlled Drug Delivery System for the Treatment of Liver Diseases in Mice
Authors: Shibuya Isao , Akaike Toshihiro , Watanabe Yoshifumi
Published: February 2005

Strict regulation of the distribution and degradation kinetics is the ultimate aim of drug delivery system. Regulation of drug delivery would increase the therapeutic efficacy and decrease the potential side effects. We encapsulated and used Z–Asp, a caspase inhibitor in poly–N–p–vinylbenzyl–D–lactonamide (PVLA) coated–poly (L–lactic acid) (PLA)–nanospheres in a mouse model of acute hepatitis. These nanospheres were internalized and accumulated in hepatocytes both in vitro and in vivo. Encapsulation significantly extended the intracellular retention time of the content in hepatocytes, which increased the bioavailability of the caspase inhibitor. In addition, the therapeutic effect was temporally controllable in vivo by modifying the component of the nanospheres. A cocktail of nanospheres with diverse degradation kinetics showed persistent therapeutic effects in acute hepatitis, and only nanospheres that targeted hepatocytes and controlled degradation rescued mice from lethal hepatic injury. This temporally and spatially controlled drug delivery system could be used in various liver diseases.
Endotoxin–Induced Mortality in Bile Duct—Ligated Rats After Administration of Reconstituted High–Density Lipoprotein
Authors: Sewnath Miguel E. , Levels Han H.M. , Elferink Ronald Oude , van Noorden Cornelis J.F. , ten Kate Fiebo J.W. , van Deventer Sander J.H. , Gouma Dirk J.
Published: February 2005

Cholestatic patients have substantial morbidity because of increased susceptibility to endotoxin (lipopolysaccharide [LPS]). Although reconstituted high–density lipoprotein (rHDL) can bind and neutralize LPS, cholestasis is associated with a near complete absence of HDL. Effects of rHDL infusion on the outcome of LPS–induced inflammatory responses in cholestatic rats were determined. Bile duct–ligated (BDL) and sham rats were treated with rHDL or saline and challenged with LPS. Distribution of cholesterol over the lipoprotein subclasses changed by ligation: levels in low–density lipoprotein (LDL) and very low–density lipoprotein (VLDL) were increased 2–fold and 5–fold, respectively, and were decreased in HDL 2–fold. rHDL treatment did not affect cholesterol distribution. LPS was mainly found in the HDL fraction, and ligation affected only levels of HDL–bound LPS (50% decrease; P < .05). Although rHDL infusion effectively normalized the lipoprotein–bound LPS distribution, it resulted in increased sensitivity (mortality: 88% in the ligation + rHDL group versus 44% in the ligation + saline group, 25% in the sham + saline group, and 0% in the sham + rHDL group, P < .05). In accordance with these results, plasma tumor necrosis factor (TNF) was significantly highest in the BDL + rHDL group at several hours after LPS challenge as well as the accumulation of LPS in the liver (P < .05). rHDL infusion leads to increased LPS–induced mortality in cholestatic rats. These results sharply contrast with the protective effects of rHDL suppletion in experimental endotoxemia in animals and human volunteers without biliary obstruction and suggest that there may be danger in administration of rHDL to cholestatic patients.
Mechanisms of Ischemic Injury Are Different in the Steatotic and Normal Rat Liver
Authors: Selzner Markus , RüDiger Hannes A. , Sindram David , Madden John , Clavien Pierre-Alain
Published: February 2005

Hepatic steatosis is associated with significant morbidity and mortality after liver resection and transplantation. Although apoptosis is a key mechanism of reperfusion injury in the normal liver, the pathway leading to cell death in steatotic hepatocytes is unknown. A model of hepatic ischemia and reperfusion injury in fatty and lean Zucker rats was used. Fatty animals had increased aspartate aminotransferase (AST) release and decreased survival after 60 minutes of ischemia compared with lean animals. Apoptosis was the predominant form of cell death in the lean rats (82%), whereas necrosis was minimal. In contrast, fatty animals developed only moderate amounts of apoptosis but showed massive necrosis (73%) after 24 hours of reperfusion. Intracellular mediators of apoptosis, such as caspase 8, caspase 3, and cytochrome c, were significantly lower in the steatotic than in the lean liver indicating dysfunction in activation of the apoptotic pathway. The high percentage of necrosis in the steatotic rats was associated with renal acute tubular necrosis after 24 hours of reperfusion in the fatty, but not in lean rats. Caspase inhibition significantly decreased reperfusion injury in lean animals, but was ineffective in fatty animals. The results indicate that the increased susceptibility of fatty livers to reperfusion injury is associated with a change from an apoptotic form of cell death to necrosis. We conclude that new therapeutic strategies are necessary in the fatty liver.
Contact atomic structure and electron transport through molecules
Authors: Ke San-Huang , Baranger Harold U. , Yang Weitao
Published: February 2005

Using benzene sandwiched between two Au leads as a model system, we investigate from first principles the change in molecular conductance caused by different atomic structures around the metal-molecule contact. Our motivation is the variable situations that may arise in break junction experiments; our approach is a combined density functional theory and Green function technique. We focus on effects caused by (1) the presence of an additional Au atom at the contact and (2) possible changes in the molecule-lead separation. The effects of contact atomic relaxation and two different lead orientations are fully considered. We find that the presence of an additional Au atom at each of the two contacts will increase the equilibrium conductance by up to two orders of magnitude regardless of either the lead orientation or different group-VI anchoring atoms. This is due to a resonance peak near the Fermi energy from the lowest energy unoccupied molecular orbital. In the nonequilibrium properties, the resonance peak manifests itself in a negative differential conductance. We find that the dependence of the equilibrium conductance on the molecule-lead separation can be quite subtle: either very weak or very strong depending on the separation regime.
Improved spatial resolution and surface roughness in photopolymerization-based laser nanowriting
Authors: Takada Kenji , Sun Hong-Bo , Kawata Satoshi
Published: February 2005

The fundamental issues on the smallest possible processing accuracy and the best feasible surface smoothness in pinpoint polymerization-based laser fabrication were experimentally investigated. The lateral spatial resolution is improved from the previously reported value, 120nm, to around 100nm by intentionally introducing radical quenchers in the resin. The roughness measured from 10μm×10μm surface areas were averaged to 4–11nm, which is found slightly affected by the laser pulse energy but independent on the scanning pitch when it is smaller than a critical value. The surface quality of this level could fully satisfy the requirement of various photonic elements and devices.
Photocurrent spectroscopy analysis of widely tunable negative-chirp quantum-well intermixed laser-modulator transmitters
Authors: Morrison G. B. , Raring J. W. , Skogen E. J. , Wang C. S. , Coldren L. A.
Published: February 2005

High-speed laser-modulator transmitters fabricated using InGaAsP quantum-well intermixing exhibit negative chirp over a wavelength range of more than 30nm. Photocurrent spectroscopy is used to examine the multiple band edges in these devices. An exciton peak is found in the photocurrent data, and the evolution of the band edge as a function of quantum-well intermixing and applied bias voltage is revealed. The photocurrent data are then exploited to verify and explain the negative chirp characteristics of the wavelength-agile transmitters.
Vertical order in stacked layers of self-assembled In(Ga)As quantum rings on GaAs (001)
Authors: Granados D. , García J. M. , Ben T. , Molina S. I.
Published: February 2005

Stacked layers of self-assembled In(Ga)As quantum rings on GaAs grown by solid source molecular beam epitaxy are studied by ex situ atomic force microscopy (AFM), low temperature photoluminescence (PL) and cross-sectional transmission electron microscopy (XTEM). The influence of the strain field and InAs segregation on the surface morphology, optical properties and vertical ordering of three quantum ring layers is analyzed for GaAs spacers between layers from 1.5 to 14 nm. AFM and PL results show that samples with spacers >6nm have surface morphology and optical properties similar to single layers samples. XTEM results on samples with 3 and 6 nm GaAs spacers show that the rings are preserved after capping with GaAs, and evidence the existence of vertically ordered quantum rings.
Correlation between domain evolution and asymmetric switching in epitaxial Pb(Zr0.52Ti0.48)O3 thin films
Authors: Wu Wenbin , Wong K. H. , Pang G. K. H. , Choy C. L.
Published: February 2005

The process-induced domain evolution and asymmetric switching in epitaxial Pb(Zr0.52Ti0.48)O3 (PZT) thin films have been studied by reciprocal space mapping, transmission electron microscopy, high-temperature x-ray diffraction, and the polarization-electric field hysteresis loop measurements. After annealing at reduced oxygen pressures, it was evidenced that an oxygen loss at the PZT bottom interface can occur at temperatures well below the Curie temperature TC, and more importantly, the oxygen loss can induce a large positive voltage offset and drive simultaneously the polydomain formation in the PZT films. Our results indicate that the structure evolution is correlated with the coercive voltage shift, and an oxygen-loss-related internal stress at the interface would be responsible for the large internal electric field in epitaxial PZT films.
Self-assembly of Al2O3 nanodots on SiO2 using two-step controlled annealing technique for long retention nonvolatile memories
Authors: Chen Jing Hao , Yoo Won Jong , Chan Daniel S. H. , Tang Lei-Jun
Published: February 2005

A self-assembly of high-density Al2O3 nanodots (NDs) on SiO2 has been demonstrated by employing a two-step controlled annealing method. Results show that the conglomeration of Al is impeded by oxygen and the size and density of Al2O3 NDs can be controlled by the initial Al film thickness and annealing temperature. Memory devices with Al2O3 NDs fabricated using this technique show improved retention properties compared to those with Al2O3 continuous films. A comparison of temperature dependency shows that the good retention property originates from the suppression of lateral migration of electrons via Frenkel–Poole tunneling.
Engineering N-linked protein glycosylation with diverse O antigen lipopolysaccharide structures in
Escherichia coli
Authors: Feldman Mario F. , Wacker Michael , Hernandez Marcela , Hitchen Paul G. , Marolda Cristina L. , Kowarik Michael , Morris Howard R. , Dell Anne , Valvano Miguel A. , Aebi Markus
Published: February 2005

Campylobacter jejuni
has a general N-linked protein glycosylation system that can be functionally transferred to
Escherichia coli
. In this study, we engineered
E. coli
cells in a way that two different pathways, protein N-glycosylation and lipopolysaccharide (LPS) biosynthesis, converge at the step in which PglB, the key enzyme of the
C. jejuni
N-glycosylation system, transfers O polysaccharide from a lipid carrier (undecaprenyl pyrophosphate) to an acceptor protein. PglB was the only protein of the bacterial N-glycosylation machinery both necessary and sufficient for the transfer. The relaxed specificity of the PglB oligosaccharyltransferase toward the glycan structure was exploited to create novel
N
-glycan structures containing two distinct
E. coli
or
Pseudomonas aeruginosa
O antigens. PglB-mediated transfer of polysaccharides might be valuable for
in vivo
production of O polysaccharides-protein conjugates for use as antibacterial vaccines.
Vertebrate Nup53 Interacts with the Nuclear Lamina and Is Required for the Assembly of a Nup93-containing Complex
Authors: Hawryluk-Gara Lisa A. , Shibuya Ellen K. , Wozniak Richard W.
Published: February 2005

The nuclear pore complex (NPC) is an evolutionarily conserved structure that mediates exchange of macromolecules across the nuclear envelope (NE). It is comprised of ∼30 proteins termed nucleoporins that are each present in multiple copies. We have investigated the function of the human nucleoporin Nup53, the ortholog of Saccharomyces cerevisiae Nup53p. Both cell fractionation and in vitro binding data suggest that Nup53 is tightly associated with the NE membrane and the lamina where it interacts with lamin B. We have also shown that Nup53 is capable of physically interacting with a group of nucleoporins including Nup93, Nup155, and Nup205. Consistent with this observation, depletion of Nup53 using small interfering RNAs causes a decrease in the cellular levels of these nucleoporins as well as the spindle checkpoint protein Mad1, likely due to destabilization of Nup53-containing complexes. The cellular depletion of this group of nucleoporins, induced by depleting either Nup53 or Nup93, severely alters nuclear morphology producing phenotypes similar to that previously observed in cells depleted of lamin A and Mad1. On basis of these data, we propose a model in which Nup53 is positioned near the pore membrane and the lamina where it anchors an NPC subcomplex containing Nup93, Nup155, and Nup205.
Salvia columbariae contains tanshinones
Authors: Adams James D. , Wall Michael , Garcia Cecilia
Published: February 2005

Salvia columbariae (chia) was examined and found to contain miltionone II, cryptotanshinone and tanshinone IIA. These compounds may be of interest in the treatment of stroke and heart attack.
Electron-transfer‐mediated binding of optically active cobalt(III) complexes to horse heart cytochromec
Authors: Scholten Ulrich , Merchán Alejandro Castillejo , Bernauer Klaus
Published: February 2005

Optically active cobalt(II) complexes are used as reducing agents in the electron-transfer reaction involving horse heart cytochromec. Analysis of the circular dichroism (CD) spectra of reaction products indicates that the corresponding cobalt(III) species of both enantiomers of [CoII(alamp)] (H2alamp=N,N′-[(pyridine-2,6-diyl)bis(methylene)]-bis[alanine]) are partly attached to the protein during electron transfer by coordination to an imidazole unit of one of the histidine residues. His-26 and His-33 are both solvent exposed, and the results suggest that one of these histidine residues acts as a bridge in the electron transfer to and from the haem iron of cytochromec. The reaction is enantioselective: the ratio of the relative reactivity at 15 °C is 2.9 in favour of theR,R-enantiomer. A small induced CD activity in the haem chromophore reveals that some structural changes in the protein occur consecutively with the binding of the cobalt(III) complex.
Direct comparison of 18F‐fluorodeoxyglucose coincidence gamma camera tomography with gallium scanning for the staging of lymphoma
Authors: Lin P. , Chu J. , Kneebone A. , Moylan E. , Jalaludin B. , Pocock N. , Kiat H. , Rosenfeld D.
Published: February 2005

Abstract

Background:  The present study compared the performance of 18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET) using a coincidence dual‐head gamma camera (FDG Co‐PET) with 67gallium scinti graphy (GS) in pretreatment staging of lymphoma.

Methods:  A total of 46 patients underwent FDG Co‐PET, computed tomography (CT) scanning and GS for pretreatment staging of lymphoma (40 newly diagnosed and recurrence) between November 1997 and December 1999.

Results:  Histological subgroups comprised low grade (8 patients), intermediate grade (25) high‐grade (3) non‐Hodgkin's lymphoma and Hodgkin's disease (10). Based on clinical assessment, CT scan findings and biopsy, 100 nodal sites and 15 extra‐nodal sites were deemed positive. FDG Co‐PET was superior to GS in nodal site positivity rate (97%vs 79%, P < 0.0001). Compared with GS, FDG Co‐PET detected 39 more abnormal sites in 22 patients (48%), of which 28 sites were validated by biopsy, CT and/or progress FDG Co‐PET scanning. There was only one proven false negative FDG site in the spleen. CT + FDG Co‐PET led to upstaging in 2 patients (4%), compared to CT + GS.

Conclusion:  FDG Co‐PET shows potential for providing an accurate means for pretreatment staging of lymphoma and can detect extra sites of disease activity compared to GS. (Intern Med J 2005; 35: 91–96)
Hot gases: The transition from line spectra to thermal radiation
Authors: Vollmer M.
Published: February 2005

The question of how the line spectrum of atoms is transformed into the continuous spectrum of thermal radiation of a gas by repeated absorption and emission of photons is addressed. We consider a simple model of a hydrogen-like gas in thermal equilibrium where only the Lyman-α transition is allowed and calculate the spectra for increasing thickness of the gas. The transition from line spectra for optically thin samples to the spectra of thermal radiation for optically thick samples is demonstrated. We estimate the emissivities for hot gases and study the line width of spectral lines due to self-absorption processes.
Schwarzschild and Birkhoff a la Weyl
Authors: Deser S. , Franklin J.
Published: February 2005

We provide a simple derivation of the Schwarzschild solution in general relativity based on an approach by Weyl, but generalized to include Birkhoff’s theorem. This theorem states that the Schwarzschild mass must be constant in time. Our procedure is illustrated by a parallel derivation of the Coulomb field and the constancy of the electric charge in electrodynamics. We also explain the basis of Birkhoff’s theorem and note that even the original Weyl approach can be used to illuminate the special role played by the Schwarzschild coordinates.
Asynchronous Bends in Pacific Seamount Trails: A Case for Extensional Volcanism?
Authors: Koppers Anthony A. P. , Staudigel Hubert
Published: February 2005

The Gilbert Ridge and Tokelau Seamounts are the only seamount trails in the Pacific Ocean with a sharp 60° bend, similar to the Hawaii-Emperor bend (HEB). These two bends should be coeval with the 47-million-year-old HEB if they were formed by stationary hot spots, and assuming Pacific plate motion only. New
40
Ar/
39
Ar ages indicate that the bends in the Gilbert Ridge and Tokelau seamount trail were formed much earlier than the HEB at 67 and 57 million years ago, respectively. Such asynchronous bends cannot be reconciled with the stationary hot spot paradigm, possibly suggesting hot spot motion or magmatism caused by short-term local lithospheric extension.
Precise Measurement of Losses in Piezoelectric Transducer and Its Application to Evaluation of Piezoelectric Transformer Efficiency
Authors: Endow Tsutomu , Hirose Seiji , Kanno Tomoyuki
Published: February 2005

Mechanical and dielectric losses were measured by the measurement method proposed in this paper in a piezoelectric transducer with input and output terminals. These losses must be considered in designing piezoelectric transformers used as power sources. In the method proposed here, the losses can be obtained using the experimental results of resonance angular frequency, quality factor and the resistive component of input impedance when the output terminals are short-circuited and opened, and using the measured phase angle difference between current and voltage when the output terminals are opened. In the method, a resonance frequency tracking circuit is utilized. Hence, there is an advantage that the measurement can be performed easily and in a short time. The results obtained by this method have also been used in the evaluation of the efficiency of piezoelectric transformers.
An Optical Flying Head Assembly for a Small-Form-Factor Plastic Disk in PCMCIA-Like Drive
Authors: Kim Sookyung , Park Jinmoo , Park Gunsoon , Lee Jungkyu , Lee Jeonguk , Jung Hewon , Kim Jin-Yong , Kim Seong-hyok , Yee Youngjoo , Kim Jong Hwan , Kim Jin Hong , Bu Jong Uk
Published: February 2005

In a small-form-factor (SFF) optical disk drive (ODD), the optical flying head (OFH) on a thin-cover-layered plastic disk requires not only uniformity of the cover layer thickness of the disk media, but also the flying stability of OFH on the plastic disk surface with low flying height variation, as well as precise tolerance management in the OFH assembly. Therefore, in order to develop a practical optical pickup head interfaced to the plastic disk, we designed the OFH with a parallel-plate electrostatic actuator for the vertical positioning of the objective lens for better flying characteristics. The flying height of the OFH is designed to be 200 nm to increase air-bearing stiffness. On the other hand, a UV resin cover layer is adopted as a protective layer and a hard and stiff plastic substrate is also adopted to increase the durability of the disk. In the evaluation of the stability of the OFH and the durability of the disk, we introduce computational and experimental results on the flying height variation of the OFH, additionally we investigated the characteristics of the durability of various plastic disks.
Selective Silicidation of Co Using Silane or Disilane for Anti-Oxidation Barrier Layer in Cu Metallization
Authors: Noda Suguru , Hirai Rika , Komiyama Hiroshi , Shimogaki Yukihiro
Published: February 2005

Aiming to realize a conductive passivation layer for copper interconnection, the solid-gas reactions of cobalt films with silane and with disilane to form cobalt silicides are experimentally investigated. X-ray photoelectron spectroscopy revealed that cobalt silicides layers of up to 6 nm thickness can be selectively formed in the reaction at 473–673 K within 5 min without detectable silicon deposition on silicon dioxide, a common inter-metal dielectric layer. Rapid thermal oxidation experiments revealed that the silicided cobalt layers had better anti-oxidation performance than untreated cobalt layers, and the effect of silicidation was to suppress copper out-diffusion through the cobalt layers. Because cobalt-based alloys can be selectively electroless-plated on copper, selective silicidation of cobalt layers will be easily incorporated into device processing.
Iterative Fourier Transform Algorithm with Adaptive Regularization Parameter Distribution for Optimal Design of Diffractive Optical Elements
Authors: Kim Hwi , Lee Byoungho
Published: February 2005

Generally, uniformity can be improved at the cost of a low diffraction efficiency in the design of diffractive optical elements by the conventional iterative Fourier transform algorithm. This trade-off is a fundamental limitation of the conventional iterative Fourier transform algorithm. However in this letter, a novel iterative Fourier transform algorithm with adaptive regularization parameter distribution for alleviating the trade-off between uniformity and diffraction efficiency and for improving uniformity is devised on the basis of the theoretical analysis of the trade-off property in the conventional iterative Fourier transform algorithm scheme. The validity of the proposed algorithm is proved by numerical experiments.
Maxi-K channels localize to caveolae in human myometrium: a role for an actin-channel-caveolin complex in the regulation of myometrial smooth muscle K+ current
Authors: Brainard Adam M. , Miller Andrea J. , Martens Jeffrey R. , England Sarah K.
Published: February 2005

Multiple cell-signaling pathways converge to modulate large-conductance, voltage- and Ca2+-sensitive K+ channel (maxi-K channel) activity and buffer cell excitability in human myometrial smooth muscle cells (hMSMCs). Recent evidence indicates that maxi-K channel proteins can target to membrane microdomains; however, their association with other proteins within these macromolecular complexes has not been elucidated. Biochemical isolation of detergent-resistant membrane fractions from human myometrium demonstrates the presence of maxi-K channels in lipid raft microdomains, which cofractionate with caveolins. In both nonpregnant and late-pregnant myometrium, maxi-K channels associate and colocalize with caveolar scaffolding proteins caveolin-1 and caveolin-2, but not caveolin-3. Disruption of cultured hMSMC caveolar complexes by cholesterol depletion with cyclodextrin increases an iberiotoxin-sensitive K+ current. Coimmunoprecipitations have indicated that the maxi-K channel also is associated with both α- and γ-actin. Immunocytochemical analysis indicates colocalization of maxi-K channels, actin, and caveolin-1 in primary cultures of hMSMCs. Further experiments using immunoelectron microscopy have shown the proximity of both actin and the maxi-K channel within the same cell surface caveolar structures. Functionally, disruption of the actin cytoskeleton in cultured hMSMCs by cytochalasin D and latrunculin A greatly increased the open-state probability of the channel, while stabilization of actin cytoskeleton with jasplakinolide abolished the effect of latrunculin A. These data indicate that the actin cytoskeleton is involved as part of a caveolar complex in the regulation of myometrial maxi-K channel function.
Functional significance of inflammatory mediators in a murine model of resuscitated hemorrhagic shock
Authors: Vallejo Jesus G. , Nemoto Shintaro , Ishiyama Masakuni , Yu Bi , Knuefermann Pascal , Diwan Abinav , Baker J. Scott , Defreitas Gilberto , Tweardy David J. , Mann Douglas L.
Published: February 2005

The mechanisms that underlie the development of myocardial dysfunction after resuscitated hemorrhagic shock (HS) are not known. Recent studies suggest that systemic activation of inflammatory mediators may contribute to cellular dysfunction and/or cell death in various organs, including the heart. However, the precise role that inflammatory mediators play in the heart in the setting of resuscitated HS is not known. Accordingly, the purpose of the present study was to use a well-defined murine model of resuscitated HS to characterize the functional significance of inflammatory mediators in the heart in vivo. Mice were subjected to sham operation or resuscitated HS. Left ventricular (LV) function was assessed by two-dimensional echocardiography 6 h after resuscitation. Myocardial TNF, IL-1β, and IL-6 proteins were measured 1 and 6 h after resuscitation. To determine the role of TNF in HS-induced LV dysfunction, mice were treated with a soluble TNF receptor antagonist (etanercept) before HS or at the time of resuscitation. LV fractional shortening was significantly depressed ( P < 0.05) in resuscitated HS mice (28 ± 1.5%) compared with sham controls (35.8 ± 1.0%). TNF and IL-1β levels were significantly increased ( P < 0.05) in resuscitated HS mice. Pretreatment with etanercept abrogated resuscitated HS-induced LV dysfunction, whereas treatment at the time of resuscitation significantly attenuated, but did not abrogate, LV dysfunction. Together, these data suggest that TNF plays a critical upstream role in resuscitated HS-induced LV dysfunction; however, once the deleterious consequences of reperfusion injury are initiated, TNF contributes to, but is not necessary for, the development of LV dysfunction.
Improvement of the specificity of dipetarudin by site directed mutagenesis
Authors: Mende Katrin , Nowak Goetz , López Mercedes
Published: February 2005

Protease specificity is crucial to the design of thrombin inhibitors as inhibition of other physiologically relevant serine-proteases can compromise their clinical use. Dipetarudin, a potent thrombin inhibitor, also inhibits trypsin and plasmin. Due to the specificity of an inhibitor being influenced by the amino acid residue at the P1 position, we replaced the Arg10 at P1 position of dipetarudin by a histidine, which is the P1 residue of rhodniin, a very specific thrombin inhibitor. The amino acid replacement was carried out by site directed mutagenesis. The mutant, dipetarudin R10H, showed a loss of plasmin and trypsin inhibitory activities present in its wild-type counterpart and a 3-fold higher dissociation constant for thrombin than dipetarudin. However, compared to dipetarudin and r-hirudin, dipetarudin R10H showed similar activity in coagulation screening assays such as activated partial thromboplastin time (aPTT), prothrombin time (PT), ecarin clotting time (ECT) and ecarin chromogenic assay (ECA).
Distribution and kinetics of SR-PSOX/CXCL16 and CXCR6 expression on human dendritic cell subsets and CD4+ T cells
Authors: Tabata Sumie , Kadowaki Norimitsu , Kitawaki Toshio , Shimaoka Takeshi , Yonehara Shin , Yoshie Osamu , Uchiyama Takashi
Published: February 2005

Dendritic cells (DCs) coordinate T cell responses by producing T cell-attracting chemokines and by inducing the expression of chemokine receptors on T cells. Scavenger receptor for phosphatidylserine and oxidized lipoprotein (SR-PSOX)/CXC chemokine ligand 16 (CXCL16) is a unique chemokine that also functions as an endocytic receptor and an adhesion molecule in its membrane-bound form. SR-PSOX/CXCL16 is the only known ligand of CXC chemokine receptor 6 (CXCR6) that is expressed on activated T cells and thus, may play an important role in enhancing effector functions of T cells. Here, we investigated the expression of SR-PSOX/CXCL16 on human DC subsets and that of CXCR6 on T cell subpopulations to elucidate the dynamics of CXCL16/CXCR6 interaction in DC/T cell responses. Membrane-bound SR-PSOX/CXCL16 was expressed on macrophages, monocyte-derived DCs, and blood myeloid DCs, and the expression increased after DC maturation. Myeloid antigen-presenting cells constitutively secreted SR-PSOX/CXCL16 for an extended period, suggesting the involvement of CXCL16 in peripheral and lymphoid tissues. Plasmacytoid DCs hardly expressed SR-PSOX/CXCL16 on their surfaces but secreted significant amounts of SR-PSOX/CXCL16. A subset of CD4+ effector memory T (TEM) cells constitutively expressed CXCR6, whereas central memory T cells (TCM) and naïve T cells did not. Upon stimulation with mature DCs, however, the expression of CXCR6 on TCM cells was markedly up-regulated, whereas the expression on naïve T cells was induced only weakly. These results suggest that the interaction between SR-PSOX/CXCL16 and CXCR6 plays an important role in enhancing TCM cell responses by mature DCs in lymphoid tissues and in augmenting TEM cell responses by macrophages in peripheral inflamed tissues.
E-cadherin intron 2 contains cis-regulatory elements essential for gene expression
Authors: Stemmler Marc P. , Hecht Andreas , Kemler Rolf
Published: February 2005

Cadherin-mediated cell-cell adhesion plays important roles in mouse embryonic development, and changes in cadherin expression are often linked to morphogenetic events. For proper embryonic development and organ formation,the expression of E-cadherin must be tightly regulated. Dysregulated expression during tumorigenesis confers invasiveness and metastasis. Except for the E-box motifs in the E-cadherin promoter, little is known about the existence and location of cis-regulatory elements controlling E-cadherin gene expression. We have examined putative cis-regulatory elements in the E-cadherin gene and we show a pivotal role for intron 2 in activating transcription. Upon deleting the genomic intron 2 entirely, the E-cadherin locus becomes completely inactive in embryonic stem cells and during early embryonic development. Later in development, from E11.5 onwards, the locus is activated only weakly in the absence of intron 2 sequences. We demonstrate that in differentiated epithelia, intron 2 sequences are required both to initiate transcriptional activation and additionally to maintain E-cadherin expression. Detailed analysis also revealed that expression in the yolk sac is intron 2 independent, whereas expression in the lens and the salivary glands absolutely relies on cis-regulatory sequences of intron 2. Taken together, our findings reveal a complex mechanism of gene regulation, with a vital role for the large intron 2.
Distinct developmental programs require different levels of Bmp signaling during mouse retinal development
Authors: Murali Deepa , Yoshikawa Shunichi , Corrigan Rebecca R. , Plas Daniel J. , Crair Michael C. , Oliver Guillermo , Lyons Karen M. , Mishina Yuji , Furuta Yasuhide
Published: February 2005

The Bmp family of secreted signaling molecules is implicated in multiple aspects of embryonic development. However, the cell-type-specific requirements for this signaling pathway are often obscure in the context of complex embryonic tissue interactions. To define the cell-autonomous requirements for Bmp signaling, we have used a Cre-loxP strategy to delete Bmp receptor function specifically within the developing mouse retina. Disruption of a Bmp type I receptor gene, Bmpr1a, leads to no detectable eye abnormality. Further reduction of Bmp receptor activity by removing one functional copy of another Bmp type I receptor gene, Bmpr1b, in the retina-specific Bmpr1a mutant background, results in abnormal retinal dorsoventral patterning. Double mutants completely lacking both of these genes exhibit severe eye defects characterized by reduced growth of embryonic retina and failure of retinal neurogenesis. These studies provide direct genetic evidence that Bmpr1a and Bmpr1b play redundant roles during retinal development, and that different threshold levels of Bmp signaling regulate distinct developmental programs such as patterning, growth and differentiation of the retina.