bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating business and residential water supply interruption losses from catastrophic events
Authors: Brozović Nicholas , Sunding David L. , Zilberman David
Published: August 2007

Following man‐made or natural catastrophes, widespread and long‐lasting disruption of lifelines can lead to economic impacts for both business and residential lifeline users. As a result, the total economic losses caused by infrastructure damage may be much higher than the value of damage to infrastructure itself. In this paper, we consider the estimation of economic impacts on businesses and residential consumers resulting from water supply disruption. The methodology we present for estimating business interruption losses assumes that marginal losses are increasing in the severity of disruption and that there may be a critical water availability cutoff below which business activity ceases. To estimate residential losses from water supply interruption, we integrate consumers' demand curves, calibrated to water agency price and quantity data. Our methodologies are spatially disaggregated and explicitly account for the time profile of infrastructure repair and restoration. As an illustration, we estimate the economic losses to business and residential water users of one of the major water supply systems of the San Francisco Bay Area of California resulting from two potential earthquake scenarios, a magnitude 7.9 event on the San Andreas Fault and a magnitude 7.1 event on the Hayward Fault. For the business loss estimation, our modeling framework is general enough to calculate and compare losses using loss functions from several previous studies. Estimated business and residential losses for the San Andreas event are $14.4 billion and $279 million, respectively. For the Hayward event, estimated business and residential losses are $9.3 billion and $37 million, respectively.
Phytoplankton blooms in the Ross Sea, Antarctica: Interannual variability in magnitude, temporal patterns, and composition
Authors: Peloquin Jill A. , Smith Walker O.
Published: August 2007

The continental shelf of the Ross Sea, Antarctica, is a unique region within the Southern Ocean. Phytoplankton growth is believed to be seasonally limited, first in austral spring by irradiance, and then in summer by biologically available iron. It also is historically known to have taxonomically distinct regimes: the south‐central portion is dominated by Phaeocystis antarctica and to the west diatoms are abundant. We measured photochemical yield to interpret the health of the phytoplankton assemblage from 2001–2004 and interfaced these measurements with satellite remote sensing of pigments. The bloom of 2001–2002 was similar in both temporal and spatial distributions to the climatological mean of the Ross Sea, with a peak in biomass being observed in mid‐December within the Ross Sea polynyas; Fv/Fm values averaged 0.43. We found high (0.50–0.65) Fv/Fm for most of the seasonal phytoplankton bloom for 2002–2003, suggesting that it was not seasonally iron limited. An unusual, large bloom occurred during 2003–2004, with an initial bloom of P. antarctica during austral spring followed by an extensive diatom bloom in summer that may have been enhanced by an intrusion of modified circumpolar deep water. On the basis of an analysis of the historical SeaWiFS records, accumulation of phytoplankton biomass in February may occur approximately every 2–4 years, potentially being a significant source of carbon on the continental shelf.
Abiotic controls on periphyton accrual and metabolism in streams: Scaling by dimensionless numbers
Authors: Warnaars Tanya A. , Hondzo Miki , Power Mary E.
Published: August 2007

Increasingly available high‐resolution topographic data from remote sensing motivates the search for topographic features that predict abiotic controls on the distribution and performance of biota. We investigated the extent to which periphyton distribution and stream ecosystem metabolism in a steep upland river drainage network could be predicted from physical conditions that varied with local topography. During the summers of 2003 and 2004, we measured periphyton standing crops and gross primary production and ecosystem respiration rates along a 5 km reach of the South Fork Eel River and six of its tributaries in northern California (39°44′N, 123°39′W). We also measured wetted stream width (B), cross‐sectionally averaged stream velocity (U), and streambed photosynthetically active solar radiation (PAR) at each site to investigate the degree to which periphyton abundance and metabolism were related to these indicators, which in turn are partially predictable from models relating environmental parameters to the topographic settings. Dimensional analysis, a technique widely used in the field of fluid mechanics, was used to investigate how biotic and abiotic variables may be interconnected in stream environments. Nondimensional groups of variables were formulated on the basis of our field estimates of chosen biotic and abiotic variables. Periphyton biomass was controlled by B9/5, exposure to light PAR1/5, nutrient concentration N5/6, and inverse stream depth H−5/6 and U−1/2. The autotrophic‐heterotrophic balance, quantified by the gross primary production to ecosystem respiration rate, scaled with the stream aspect ratio (B/H) and Peclet number Pe = (UB/u*H), where u* is the shear stress velocity. The scaling relationships were validated against reported field measurements from other geographical areas. The results show nonlinear dependencies among periphyton biomass, stream metabolism, and abiotic variables. These nonlinear relationships point to a need for detailed quantification of biotic and abiotic variables over a range of scales.
Solving the mystery of booming sand dunes
Authors: Vriend Nathalie M. , Hunt Melany L. , Clayton Robert W. , Brennen Christopher Earls , Brantley Katherine S. , Ruiz‐Angulo Angel
Published: August 2007

Desert booming can be heard after a natural slumping event or during a sand avalanche generated by humans sliding down the slip face of a large dune. The sound is remarkable because it is composed of one dominant audible frequency (70 to 105 Hz) plus several higher harmonics. This study challenges earlier reports that the dunes' frequency is a function of average grain size by demonstrating through extensive field measurements that the booming frequency results from a natural waveguide associated with the dune. The booming frequency is fixed by the depth of the surficial layer of dry loose sand that is sandwiched between two regions of higher compressional body wave velocity. This letter presents measurements of the booming frequencies, compressional wave velocities, depth of surficial layer, along with an analytical prediction of the frequency based on constructive interference of propagating waves generated by avalanching along the dune surface.
Nanometer hypervelocity dust impacts in low Earth orbit
Authors: Carpenter J. D. , Stevenson T. J. , Fraser G. W. , Bridges J. C. , Kearsley A. T. , Chater R. J. , Hainsworth S. V.
Published: August 2007

A study has been made of 60 nm thick aluminum films which have been exposed to the space environment outside of International Space Station (ISS) between 2002 and 2004. Field emission scanning electron microscopy has been used to provide high‐resolution images of impact features less than 100 nm in diameter and of detailed impact morphologies at different spatial scales. Analysis of images reveals the incident directions and diameters of the impacting particles and allows separation of impacts at hypervelocity from those at lower velocities. This allows the separation of different particle populations. We find that most detected particles have been generated locally as the result of secondaries following larger impacts elsewhere on the ISS or as a result of docking maneuvers by the Progress supply module or by other spacecraft. There is also evidence for a population of dust particles incident at hypervelocity and with minimum diameters smaller than 10 nm. This particle flux of the dust particles is consistent with the expected flux of micrometeoroids with mass >10−18 g at 1 AU and may represent the first measurement of dust particles with such small masses in near‐Earth space. Future experiments to measure the flux of nanometer‐scale dust particles are proposed, both passive exposure cells for retrieval and also active detectors to provide access to dust/debris populations without the requirement for experiment retrieval.
The Use of Critical Solution Mixtures for Contaminated Sediments Remediation
Authors: Golan Tal , Ludmer Zvi , Ermolenko Elena , Brauner Neima , Ullmann Amos
Published: August 2007

Using a critical solution mixture, into which chelating agents have been dissolved, resulted in the efficient, rapid and simultaneous removal of both heavy metals and organic pollutants from contaminated sediments. Both heating and cooling across the immiscibility curve and isothermal extraction were investigated. In addition, the extraction yields were compared to those obtained with solution mixtures that do not possess a critical point of miscibility. Extraction yields of the former were superior to those of the latter in the range of relevant pressures (1 atm.) and temperatures. Extraction via heating and cooling across the miscibility curve resulted in the removal of close to 90% of the heavy metals and practically all of the organic contaminants, compared to only about 40% when the extraction was performed isothermally at around 20oC.
Oxygen and Glucose Deprivation-Induced Changes in Astrocyte Membrane Potential and Their Underlying Mechanisms in Acute Rat Hippocampal Slices
Authors: Xie Minjie , Wang Wei , Kimelberg Harold K , Zhou Min
Published: August 2007

Accumulating evidence indicates a significant astrocytic involvement in cerebral ischemia neuropathology, but little is known about the immediate astrocytic responses to ischemia insults in terms of electrophysiology and their pathologic implications. We show that astrocytes in acute rat hippocampal slices responded reversibly to more than 30 mins oxygen and glucose deprivation (OGD) treatment with depolarized membrane potentials ( Vm) in whole-cell current clamp recording. This depolarization was multiphasic, showing an initial ~11 mins small-amplitude depolarization plateau, followed by a 6-mins accelerated depolarization, and then a second plateau. Oxygen and glucose deprivation-induced astrocyte Vm depolarization was only marginally inhibited, ~10%, by inhibition of ionotropic glutamate, γ-aminobutyric acid, purinergic receptors, and glutamate transporters presumed to be present on astrocytes in situ, suggesting increase in extracellular [K+] was primarily responsible for the astrocytic Vm change. The Vm depolarization was five-fold greater when glycolysis was inhibited by iodoacetate in a short 8 mins OGD treatment, suggesting glycolytic ATP is critical in maintaining extracellular K+ homeostasis in the early phase of OGD. Addition of oxidative metabolism inhibitors had much less effect. Cessation of OGD was always followed by a rapid and transient 9 mV astrocyte Vm hyperpolarization relative to the control Vm that was inhibited by ouabain, indicating a reactively enhanced Na+/K+-ATPase activity in post-OGD reperfusion. Altogether, hippocampal astrocytes appear to be electrophysiologically more resistant to acute ischemia insults as compared with neurons, and this should allow astrocytes to rescue endangered neurons in the face of acute ischemia insults via their various homeostatic functions.
Nonlinear optical properties of polydiacetylene with donor-acceptor substitution block
Authors: Ohnishi Shin-ichi , Orimoto Yuuichi , Gu Feng Long , Aoki Yuriko
Published: August 2007

The elongation finite-field (elongation-FF) method is applied to donor/acceptor substituted polydiacetylenes (PDAs) for the estimation of substituent effects on nonlinear optical (NLO) properties. The first hyperpolarizability (β) and the second hyperpolarizability (γ) of PDA with separated donor and acceptor substitution blocks have much larger values than those of the other substituted PDAs. For the PDAs with donor and acceptor substitution blocks, the relationship between the NLO properties and the block period is examined. It is shown, from the local density of states, that γ of a system with a quantum well structure has a maximum value at a certain block size. This indicates that by tuning the size of proper block it is possible to achieve the largest γ value in block polymers. Furthermore, the through-space/bond interaction analysis is performed to examine the π-conjugation effects on the NLO properties for particular substituted PDA. It is demonstrated by our quantitative analysis that β is affected by electron transfers in the molecule, and the quantum well structure is critical for γ improvement.
On the calculation of Mössbauer isomer shift
Authors: Filatov Michael
Published: August 2007

A quantum chemical computational scheme for the calculation of isomer shift in Mössbauer spectroscopy is suggested. Within the described scheme, the isomer shift is treated as a derivative of the total electronic energy with respect to the radius of a finite nucleus. The explicit use of a finite nucleus model in the calculations enables one to incorporate straightforwardly the effects of relativity and electron correlation. The results of benchmark calculations carried out for several iron complexes as well as for a number of atoms and atomic ions are presented and compared with the available experimental and theoretical data.
Polarization dependent electrostrictive grating measurements
Authors: Rozouvan Stanislav
Published: August 2007

The laser induced grating spectroscopy experiments were performed with different polarizations of 1064nm laser pump beams. Thermal and electrostrictive gratings were observed in the mixture of nitrogen at high pressure with methanol vapor. Suppression of gratings by a continuous change of pump beam polarizations was verified both theoretically and experimentally. Odd and even peaks of the registered signal were found to be responsible, respectively, for electrostrictive and thermal gratings in gas media.
Solvent resonance effect on the anisotropy of NO−(N2O)n cluster anion photodetachment
Authors: Velarde Luis , Habteyes Terefe , Grumbling Emily R. , Pichugin Kostyantyn , Sanov Andrei
Published: August 2007

Photodetachment from NO−(N2O)n cluster anions (n⩽7) is investigated using photoelectron imaging at 786, 532, and 355nm. Compared to unsolvated NO−, the photoelectron anisotropy with respect to the laser polarization direction diminishes drastically in the presence of the N2O solvent, especially in the 355nm data. In contrast, a less significant anisotropy loss is observed for NO−(H2O)n. The effect is attributed to photoelectron scattering on the solvent, which in the N2O case is mediated by the Π2 anionic resonance. No anionic resonances exist for H2O in the applicable photoelectron energy range, in line with the observed difference between the photoelectron images obtained with the two solvents. The momentum-transfer cross section, rather than the total scattering cross section, is argued to be an appropriate physical parameter predicting the solvent effects on the photoelectron angular distributions in these cluster anions.
Vapor-liquid coexistence of patchy models: Relevance to protein phase behavior
Authors: Liu Hongjun , Kumar Sanat K. , Sciortino Francesco
Published: August 2007

The vapor-liquid coexistence boundaries of fluids composed of particles interacting with highly directional patchy interactions, in addition to an isotropic square well potential, are evaluated using grand canonical Monte Carlo simulations combined with the histogram reweighting and finite size scaling methods. We are motivated to study this more complicated model for two reasons. First, it is established that the reduced widths of the metastable vapor-liquid coexistence curve predicted by a model with only isotropic interparticle interactions are much too narrow when compared to the experimental phase behavior of protein solutions. Second, interprotein interactions are well known to be “patchy.” Our results show that at a constant total areal density of patches, the critical temperature and the critical density increase monotonically with an increasing number of uniformly spaced patches. The vapor-liquid coexistence curves plotted in reduced coordinates (i.e., the temperature and the density scaled by their respective critical values) are found to be effectively independent of the number of patches, but are much broader than those found for the isotropic models. Our findings for the reduced width of the coexistence curve are almost in quantitative agreement with the available experimental data for protein solutions, stressing the importance of patchiness in this context.
High resolution EPR spectroscopy of C60F and C70F in solid argon: Reassignment of C70F regioisomers
Authors: Misochko E. Ya. , Akimov A. V. , Belov V. A. , Tyurin D. A. , Laikov D. N.
Published: August 2007

Free radicals C60F and C70F were generated in solid argon by means of chemical reaction of photogenerated fluorine atoms with isolated fullerene molecules (C60 or C70). High resolution anisotropic electron paramagnetic resonance (EPR) spectra of C60F and C70F at low temperature have been obtained for the first time. The spectrum of C60F is characterized by an axially symmetric hyperfine interaction on F19 nucleus. The hyperfine coupling constants Aiso=202.8MHz (Fermi contact interaction) and Adip=51.8MHz (electron-nuclear magnetic-dipole interaction) have been measured for C60F in solid argon. Quantum chemical calculations using hybrid density-functional models (either PBE0 or B3LYP) with high-quality basis sets give a theoretical estimate of the hyperfine coupling constants in good agreement with the measurements. The electron spin density distribution in C60F is theoretically characterized using the Hirshfeld atomic partitioning scheme. Unlike C60, five isomers of C70F can in principle be produced by the attachment of a fluorine atom to one of the five distinct carbon atoms of the C70 molecule (denoted A, B, C, D, and E, from pole to equator). The measured high resolution EPR spectrum of the C70+F reaction products is interpreted to show the presence of only three regioisomers of C70F. Based on the comparison of the measured hyperfine constants with those estimated by the quantum chemical calculation, an assignment of the spectra to the isomers (A, C, and D) is made, which differs strongly from the previous one [J. R. Morton, K. F. Preston, and F. Negri, Chem. Phys. Lett. 221, 59 (1994)]. The new assignment would allow the conclusion that the low-temperature attachment of F atom to the asymmetric CC bonds of C70 molecule, namely, CACB and CDCE, shows remarkably high selectivity, producing only one of the two isomers in each case, A and D, respectively. Theoretical investigation of the reaction mechanism is made, and it shows that the attachment reaction should have no barrier in the gas phase. The thermodynamic equilibration of the C70F isomers is excluded by the high activation energy (∼30kcal∕mol) for the F atom shifts. The explanation of the high selectivity presents a challenge for theoretical modeling.
Optically driven viscous micropump using a rotating microdisk
Authors: Maruo Shoji , Inoue Hiroyuki
Published: August 2007

An optically driven micropump using viscous drag exerted on a rotating disk microrotor was developed. The disk microrotor (diameter of 10μm), which has three columns as targets for the optical trap, is confined to a U-shaped microchannel. To pump fluid, the disk microrotor is rotated by a time-shared optical trapping technique. The flow field inside the U-shaped microchannel was analyzed using finite element method (FEM) based on the Navier-Stokes equation. The optimized micropump was fabricated using a two-photon microfabrication technique. The flow rate of the micropump agreed with simulation result obtained by FEM analysis.
Markov random field aided Bayesian approach for image reconstruction in confocal microscopy
Authors: Mondal Partha Pratim , Vicidomini Giuseppe , Diaspro Alberto
Published: August 2007

The inverse problem associated with microscopic image reconstruction has attracted much attention and initiated a lot of interest in microscopic image processing. The inverse problem of image reconstruction from noisy and incomplete data is still one of the key factors for realizing the full potential of optical microscopy. We propose to address the inverse problem using Markov random field in the Bayesian domain. This approach has the potential advantage of incorporation of prior knowledge in the reconstruction process through the prior function, thus making the problem well-posed and computationally efficient for three-dimensional (3D) image reconstruction. Image reconstruction on 3D phantom and microscopic specimens shows comparatively noise-free and better-resolved images. The edges and minute features such as islets are well reconstructed. We believe that the proposed image reconstruction methodology will find applications in microscopy and imaging.
Parylene cantilevers integrated with polycrystalline silicon piezoresistors for surface stress sensing
Authors: Katragadda Rakesh , Wang Zhuo , Khalid Waqas , Li Yuefa , Xu Yong
Published: August 2007

Polymer based microcantilevers are known to have higher sensitivity than their silicon counterparts for surface stress sensing, owing to the lower Young’s modulus of polymers. This letter reports the development of parylene cantilevers integrated with polycrystalline silicon piezoresistors for the detection of chemical or biological molecules based on the surface stress sensing principle. The justification of using parylene is presented with theoretical calculations along with finite element simulation. The fabrication process employed for making these devices is also reported. The functionality of the sensor was preliminarily proven by the detection of octanethiol vapors. The stability of the sensor in water was demonstrated as well.
Magnetoacoustic tomographic imaging of electrical impedance with magnetic induction
Authors: Xia Rongmin , Li Xu , He Bin
Published: August 2007

Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging tissue electrical impedance properties by integrating magnetic induction and ultrasound measurements. In the present study, the authors have developed a focused cylindrical scanning mode MAT-MI system and the corresponding reconstruction algorithms. Using this system, they demonstrated a three-dimensional MAT-MI imaging approach in a physical phantom, with cylindrical scanning combined with ultrasound focusing, and the ability of MAT-MI in imaging electrical conductivity properties of biological tissue.
First-principles theory for Si-based, atomically thin layered semiconductor crystal
Authors: Miyazaki Takehide , Kanayama Toshihiko
Published: August 2007

The authors predict, based on first principles density-functional theory total-energy calculations, that a Si-based, atomically thin layered compound (MoSi12)n is a semiconductor with the energy band gap being ∼0.5eV in the generalized gradient approximation. In this material a layer of Mo atoms is sandwiched by two layers of Si atoms in graphenelike positions with corrugations in the film-normal direction. The stability of this material arises from the Si–Si sp3-like covalent bonding enhanced by the corrugations and also from the Mo–Si interactions characterized by both covalent and charge-transfer natures.
Blue electroluminescent properties of poly(N-arylcarbazole-2,7-ylene) homopolymers
Authors: Kobayashi Norifumi , Kijima Masashi
Published: August 2007

To investigate electroluminescence behaviors of a series of poly(N-phenyl-2,7-carbazole)s having 2-ethylhexyloxy (PEHOC), triethylene oxide (PTEOC), or diphenylamino (PDPAC) group at the N-phenyl portion, single-layer devices of organic light-emitting diode using the as-prepared polymer as the emitting layer material were fabricated. All the devices showed brightness above 1000cd∕m2 at 10V with moderate luminous efficiencies. The PEHOC (m, p-disubstituted) and PTEOC (p-substituted) devices exhibited a trivial but undesirable redshift due to electro-oxidation and aggregation of the polymer under high driving voltages, while the PDPAC (m-substituted) device displayed a blue electroluminescence [λmax=450nm and CIE (x,y)=0.159,0.173] which had no difference compared with the photoluminescence spectrum.
Modification of the electronic properties of GaN nanowires by Mn doping
Authors: Chen Xihong , Lee Seung Joon , Moskovits Martin
Published: August 2007

The electronic transport properties of individual GaN nanowire configured as field-effect transistors (FETs) show them to be highly conductive n-type semiconductors. Accordingly, the source-drain current (ISD) of these FETs cannot be varied significantly by the gate potential. When doped with Mn by thermal diffusion, the carrier density of resultant nanowire drops approximately two orders of magnitude likely due to the fact that Mn doping produces deep acceptor states that compensate for the native shallow donors of as-grown GaN nanowires. The ISD of the Mn-doped GaN nanowires could be modulated by a factor of 5 using the gate potential.
Effective electrical passivation of Ge(100) for high-k gate dielectric layers using germanium oxide
Authors: Delabie Annelies , Bellenger Florence , Houssa Michel , Conard Thierry , Van Elshocht Sven , Caymax Matty , Heyns Marc , Meuris Marc
Published: August 2007

In search of a proper passivation for high-k Ge metal-oxide-semiconductor devices, the authors have deposited high-k dielectric layers on GeO2, grown at 350–450°C in O2. ZrO2, HfO2, and Al2O3 were deposited by atomic layer deposition (ALD). GeO2 and ZrO2 or HfO2 intermix during ALD, together with partial reduction of Ge4+. Almost no intermixing or reduction occurs during Al2O3 ALD. Capacitors show well-behaved capacitance-voltage characteristics on both n- and p-Ge, indicating efficient passivation of the Ge∕GeOx interface. The density of interface states is typically in the low to mid-1011cm−2eV−1 range, approaching state-of-the-art Si∕HfO2∕matal gate devices.
Apoptotic cells protect mice from autoimmune inflammation by the induction of regulatory B cells
Authors: Gray M. , Miles K. , Salter D. , Gray D. , Savill J.
Published: August 2007

The maintenance of immune tolerance to apoptotic cells (AC) within an inflammatory milieu is vital to prevent autoimmunity. To investigate this, we administered syngeneic AC i.v. into mice carrying a cohort of ovalbumin (OVA)-specific transgenic T cells (DO11.10) along with OVA peptide and complete Freund's adjuvant, observing a dramatic increase in OVA-specific IL-10 secretion. Activated splenic B cells responded directly to AC, increasing secretion of IL-10, and this programming by AC was key to inducing T cell-derived IL-10. We went on to ask whether AC are able to modulate the course of autoimmune-mediated, chronic inflammation. AC given up to 1 month before the clinical onset of collagen-induced arthritis protected mice from severe joint inflammation and bone destruction. Antigen-specific CD4+T cells again secreted significantly more IL-10, associated with a reduced titer of pathogenic anti-collagen II antibodies. Inhibition of IL-10in vivoreversed the beneficial effects of AC. Passive transfer of B cells from AC-treated mice provided significant protection from arthritis. These data demonstrate that AC exert a profound influence on an adaptive immune response through the generation of CD19+regulatory B cells, which in turn are able to influence the cytokine profile of antigen-specific effector T cells.
Vertebrate heart growth is regulated by functional antagonism between Gridlock and Gata5
Authors: Jia Haibo , King Isabelle N. , Chopra Sameer S. , Wan Haiyan , Ni Terri T. , Jiang Charlie , Guan Xiaoqun , Wells Sam , Srivastava Deepak , Zhong Tao P.
Published: August 2007

Embryonic organs attain their final dimensions through the generation of proper cell number and size, but the control mechanisms remain obscure. Here, we establish Gridlock (Grl), a Hairy-related basic helix–loop–helix (bHLH) transcription factor, as a negative regulator of cardiomyocyte proliferative growth in zebrafish embryos. Mutations in
grl
cause an increase in expression of a group of immediate-early growth genes, myocardial genes, and development of hyperplastic hearts. Conversely, cardiomyocytes with augmented Grl activity have diminished cell volume and fail to divide, resulting in a marked reduction in heart size. Both bHLH domain and carboxyl region are required for Grl negative control of myocardial proliferative growth. These Grl-induced cardiac effects are counterbalanced by the transcriptional activator Gata5 but not Gata4, which promotes cardiomyocyte expansion in the embryo. Biochemical analyses show that Grl forms a complex with Gata5 through the carboxyl region and can repress Gata5-mediated transcription via the bHLH domain. Hence, our studies suggest that Grl regulates embryonic heart growth via opposing Gata5, at least in part through their protein interactions in modulating gene expression.
Cortical dysplasia and skull defects in mice with a
Foxc1
allele reveal the role of meningeal differentiation in regulating cortical development
Authors: Zarbalis Konstantinos , Siegenthaler Julie A. , Choe Youngshik , May Scott R. , Peterson Andrew S. , Pleasure Samuel J.
Published: August 2007

We report the identification of a hypomorphic mouse allele for
Foxc1
(

Foxc1
hith

) that survives into adulthood revealing previously unknown roles for Foxc1 in development of the skull and cerebral cortex. This line of mice was recovered in a forward genetic screen using ENU mutagenesis to identify mutants with cortical defects. In the
hith
allele a missense mutation substitutes a Leu for a conserved Phe at amino acid 107, leading to destabilization of the protein without substantially altering transcriptional activity. Embryonic and postnatal histological analyses indicate that diminished Foxc1 protein expression in all three layers of meningeal cells in

Foxc1
hith/hith

mice contributes to the cortical and skull defects in mutant mice and that the prominent phenotypes appear as the meninges differentiate into pia, arachnoid, and dura. Careful analysis of the cortical phenotypes shows that

Foxc1
hith/hith

mice display detachment of radial glial endfeet, marginal zone heterotopias, and cortical dyslamination. These abnormalities have some features resembling defects in type 2 (cobblestone) lissencephaly or congenital muscular dystrophies but appear later in corticogenesis because of the delay in breakdown of the basement membrane. Our data reveal that the meninges regulate the development of the skull and cerebral cortex by controlling aspects of the formation of these neighboring structures. Furthermore, we provide evidence that defects in meningeal differentiation can lead to severe cortical dysplasia.
Resolving vesicle fusion from lysis to monitor calcium-triggered lysosomal exocytosis in astrocytes
Authors: Jaiswal Jyoti K. , Fix Marina , Takano Takahiro , Nedergaard Maiken , Simon Sanford M.
Published: August 2007

Optical imaging of individual vesicle exocytosis is providing new insights into the mechanism and regulation of secretion by cells. To study calcium-triggered secretion from astrocytes, we used acridine orange (AO) to label vesicles. Although AO is often used for imaging exocytosis, we found that imaging vesicles labeled with AO can result in their photolysis. Here, we define experimental and analytical approaches that permit us to distinguish unambiguously between fusion, leakage, and lysis of individual vesicles. We have used this approach to demonstrate that lysosomes undergo calcium-triggered exocytosis in astrocytes.
Protection against telomeric position effects by the chicken cHS4 β-globin insulator
Authors: Rincón-Arano Héctor , Furlan-Magaril Mayra , Recillas-Targa Félix
Published: August 2007

Epigenetic silencing of genes relocated near telomeres, termed telomeric position effect, has been extensively studied in yeast and more recently in vertebrates. However, protection of a transgene against telomeric position effects by chromatin insulators has not yet been addressed. In this work we investigated the capacity of the chicken β-globin insulator cHS4 to shield a transgene against silencing by telomeric heterochromatin. Using telomeric repeats, we targeted transgene integration into telomeres of the chicken cell line HD3. When the chicken cHS4 insulator is incorporated to the transgene, we observe a sustained gene expression of single-copy integrants that can be maintained for >100 days of continuous culture. However, uninsulated single-copy clones showed an accelerated gene expression extinction profile. Unexpectedly, telomeric silencing was not reversed with trichostatin A or nicotidamine. In contrast, significant reactivation was obtained with 5-aza-2′-deoxycytidine, consistent with the subtelomeric DNA methylation status. Strikingly, insulated transgenes integrated into telomeric regions were enriched in histone methylation, such as H3K4me2 and H3K79me2, but not in histone acetylation. Furthermore, the cHS4 insulator counteracts telomeric position effects in an upstream stimulatory factor-independent manner. Our results suggest that this insulator has the capacity to adapt to different chromatin propagation signals in distinct insertional epigenome environments.
Searching for species in haloarchaea
Authors: Papke R. Thane , Zhaxybayeva Olga , Feil Edward J. , Sommerfeld Katrin , Muise Denise , Doolittle W. Ford
Published: August 2007

Prokaryotic (bacterial and archaeal) species definitions and the biological concepts that underpin them entail clustering (cohesion) among individuals, in terms of genome content and gene sequence similarity. Homologous recombination can maintain gene sequence similarity within, while permitting divergence between, clusters and is thus the basis for recent efforts to apply the Biological Species Concept in prokaryote systematics and ecology. In this study, we examine isolates of the haloarchaeal genus
Halorubrum
from two adjacent ponds of different salinities at a Spanish saltern and a natural saline lake in Algeria by using multilocus sequence analysis. We show that, although clusters can be defined by concatenation of multiple marker sequences, barriers to exchange between them are leaky. We suggest that no nonarbitrary way to circumscribe “species” is likely to emerge for this group, or by extension, to apply generally across prokaryotes. Arbitrary criteria might have limited practical use, but still must be agreed upon by the community.
Crystal structure of the incretin-bound extracellular domain of a G protein-coupled receptor
Authors: Parthier Christoph , Kleinschmidt Martin , Neumann Piotr , Rudolph Rainer , Manhart Susanne , Schlenzig Dagmar , Fanghänel Jörg , Rahfeld Jens-Ulrich , Demuth Hans-Ulrich , Stubbs Milton T.
Published: August 2007

Incretins, endogenous polypeptide hormones released in response to food intake, potentiate insulin secretion from pancreatic β cells after oral glucose ingestion (the incretin effect). This response is signaled by the two peptide hormones glucose-dependent insulinotropic polypeptide (GIP) (also known as gastric inhibitory polypeptide) and glucagon-like peptide 1 through binding and activation of their cognate class 2 G protein-coupled receptors (GPCRs). Because the incretin effect is lost or significantly reduced in patients with type 2 diabetes mellitus, glucagon-like peptide 1 and GIP have attracted considerable attention for their potential in antidiabetic therapy. A paucity of structural information precludes a detailed understanding of the processes of hormone binding and receptor activation, hampering efforts to develop novel pharmaceuticals. Here we report the crystal structure of the complex of human GIP receptor extracellular domain (ECD) with its agonist, the incretin GIP
1–42
. The hormone binds in an α-helical conformation in a surface groove of the ECD largely through hydrophobic interactions. The N-terminal ligand residues would remain free to interact with other parts of the receptor. Thermodynamic data suggest that binding is concomitant with structural organization of the hormone, resulting in a complex mode of receptor–ligand recognition. The presentation of a well structured, α-helical ligand by the ECD is expected to be conserved among other hormone receptors of this class.
Genetic modulation of cognitive flexibility and socioemotional behavior in rhesus monkeys
Authors: Izquierdo Alicia , Newman Timothy K. , Higley J. Dee , Murray Elisabeth A.
Published: August 2007

In human and nonhuman primates, structural variants of the gene encoding the serotonin transporter [5-hydroxytryptamine transporter (5-HTT)] affect the transcription and functional efficacy of 5-HTT. Prior work has shown that structural variants differentially affect function of the amygdala and ventromedial prefrontal cortex (VMPFC), regions important for the regulation and expression of emotion. However, relatively little is known about the impact of 5-HTT allelic variants on cognition. To address this question, we tested rhesus monkeys carrying orthologous structural variants of 5-HTT on a battery of tasks that assess cognitive flexibility, reward processing, and emotion. Here we show that rhesus monkeys carrying two copies of the short allele (SS) of the rhesus 5-HTT gene-linked polymorphic region (rh5-HTTLPR) show significantly reduced cognitive flexibility as measured by two tasks in the battery: object discrimination reversal learning and instrumental extinction. Monkeys with the SS genotype also displayed alterations in socioemotional behavior. Genotype variation was not related to visual perceptual abilities, valuation of food rewards, or the ability to express a wide range of defensive responses. Although emotional alterations associated with 5-HTT variation have been described as the primary phenotype, the present study reports differences in at least one type of cognitive flexibility, which has not been described previously. Because behaviors modulated by the 5-HTTLPR are a subset of those dependent on the VMPFC, analysis of structural and functional correlates of gene variation in this region may inform the nature of the genetic modulation of cognition.
Clinical and urodynamic parameters associated with history of urinary tract infections in women: a prospective study
Authors: ATHANASIOU STAVROS , ANTSAKLIS ARIS , BETSI GREGORIA I. , SOTIROPOULOU MYRTIA , FALAGAS MATTHEW E.
Published: August 2007

Objectives. To evaluate the association of various clinical and urodynamic variables with history of urinary tract infections (UTIs) in women. Methods. A prospective study of 2,081 women referred to a urogynecologic clinic between June 2000 and November 2005 for investigation of lower urinary tract symptoms. Results. 144 women reported history of UTI(s) within the last year from the visit to the clinic, and 91 had recurrent episodes (≥3 per year). The multivariable analysis showed that urge incontinence (odds ratio (OR) = 2.23, 95% confidence interval (CI): 1.46–3.42), suprapubic pain (OR = 4.12, 95% CI: 2.21–7.67), and low maximum flow rate during voiding cystometry (OR = 0.96, 95% CI: 0.94–0.98) were associated with UTIs. Conclusions. Our results suggest that urodynamic testing does not help in identifying specific urogynecologic mechanisms that could improve medical and/or surgical management or prevent recurrent UTI.
Which factors influenced the result of a tension free vaginal tape operation in a single teaching hospital?
Authors: WITHAGEN M.I.J. , MILANI A.L.
Published: August 2007

Background. Tension free vaginal tape (TVT) has proven to be successful. Nevertheless, complications of the TVT have been reported. The aim of this study was to describe factors that might influence the efficacy and safety of the TVT procedure in our clinic. Methods. Medical records of all patients who underwent TVT surgery between 1 January 2001 and 1 May 2004 were reviewed. To achieve subjective follow‐up, in 2004 and 2005, we sent all patients standardised validated questionnaires. Data were analysed with SPSS. Results. A total of 198 TVT procedures were performed. In 75 cases (37.9%), the procedure was combined with vaginal prolapse surgery. Complications were found in 19.7% of all TVT procedures. Most patients (71%) returned the questionnaire. Median follow‐up was 27 months (range: 9–49). Subjective success rate was 73%. Logistic regression analysis showed that success rate of the TVT procedure was not influenced by any of the factors we studied. Complications were not more common in patients who had undergone prior incontinence or prolapse surgery. Concomitant prolapse surgery with the TVT, however, was found to be the only risk factor for complications, mainly prolonged catheterisation. Conclusions. In this study, we found no factor that influenced the success rate of the TVT. In the literature, the experience of the surgeon is marked as a factor influencing the success rate. We, therefore, gradually reduced the number of gynecologists who perform TVT. Concomitant prolapse surgery, however, was shown to be an independent risk factor for complications. Therefore, we prefer to ‘separate’ prolapse and incontinence surgery.
Sense of coherence and symptoms of post‐traumatic stress after emergency caesarean section
Authors: THAM VIBEKE , CHRISTENSSON KYLLIKE , RYDING ELSA LENA
Published: August 2007

Background. In this study of women who had undergone an emergency caesarean section (EmCS), the aim was to examine the associations between, on the one hand, the new mother's sense of coherence (SOC) and obstetric and demographic variables a few days postpartum, and on the other hand, post‐traumatic stress symptoms 3 months’ postpartum. Methods. In a prospective study, 122 Swedish‐ or English‐speaking new mothers completed 2 self‐assessment questionnaires, at 2 days and 3 months after an EmCS. To measure SOC, we used the Sense of Coherence Scale (SOC‐13), and to measure reactions to traumatic events, the Impact of Event Scale (IES‐15). Results. Independent risk factors associated with post‐traumatic stress symptoms were: imminent fetal asphyxia as an indication for the operation, and low SOC in the woman. The group of women with low SOC were those with an intense fear of childbirth during pregnancy, immigrants, and socially underprivileged women. Conclusions. Symptoms of post‐traumatic stress following EmCS are associated both with the new mother's personal coping style and with the circumstances of the event. We recommend that women who belong to groups who more often report a low SOC or who had imminent asphyxia as an indication for the operation should be offered support and follow‐up.
Post‐cesarean surgical site infections according to CDC standards: rates and risk factors. A prospective cohort study
Authors: OPØIEN HANS KRISTIAN , VALBØ ANNELILL , GRINDE‐ANDERSEN ANETTE , WALBERG METTE
Published: August 2007

Objectives. The aim of this study was to document the true incidence of post‐cesarean surgical site infections (SSI), according to the definition of the US Centers for Disease Control and Prevention (CDC), and to identify independent risk factors for infection. Design. Prospective population‐based cohort study in Norway. Setting. Sykehuset Asker og Bærum HF, a secondary community hospital, associated with the University of Oslo (UiO), Norway, accounting for 2,000 deliveries per year. Participants. All cesarean deliveries during a 12‐month period from September 2003. Main outcome measures. Rate and risk factors for SSI. Results. The total rate of SSI was 8.9%, with an observation period of 30 days post‐operatively, compared to 1.8% registered at hospital discharge. The total response rate was 100%. There was no significant difference in SSI rate in elective or emergency cesarean section (CS), respectively. All SSI were superficial. We found 2 significant independent risk factors: operating time ≥38 min and body mass index (BMI) >30. Conclusion. The rate of SSI is underestimated if the observation time is limited to the hospital stay. Operating time exceeding 38 min substantially increases the risk of SSI. The finding of no significant difference in SSI rate between elective and emergency CS should lead to a different approach concerning the use of antibiotics: subgroup at risk (operating time ≥38 min and BMI >30) may benefit from antibiotics in relation to the operation, whether the CS is an emergency or elective operation.
From Moldovanism to Europeanization? Moldova's Communists and Nation Building*
Authors: March Luke
Published: August 2007

The Party of Communists of the Republic of Moldova (PCRM) has been a highly controversial actor since its election in February 2001. The party initially governed under a hail of domestic and international criticism for its East-leaning foreign policy and authoritarian domestic politics. Yet, although with a diminished vote share, it was re-elected on 6 March 2005 in broadly free and fair elections on a pro-European platform with relations with Russia at a nadir.
Housing Property as a Major Dispute over Power and Allocation of Rights in Post-War Kosovo: A Legal Plurality Case?
Authors: Kretsi Georgia
Published: August 2007

While a large number of Kosovo Albanians before the war longed for international intervention in their province, after the “national victory” social and economic grievances put an end to the illusion of a “great” future in a “free” Kosovo. High unemployment rates as well as property and housing became the most vital issues for a majority of the Kosovar population. For minorities such as the Roma, Ashkali, Egyptians, and Serbs, issues of security and future integration in an eventually independent, Albanian-dominated country were added to the general economic crisis and to the difficulties of repossessing properties lost as a result of the war.
Differential Roles of CD36, ICAM‐1, and P‐selectin in Plasmodium falciparum Cytoadherence In Vivo
Authors: Yipp Bryan G. , Hickey Michael J. , Andonegui Graciela , Murray Allan G. , Looareesuwan Sornchai , Kubes Paul , Ho May
Published: August 2007

ABSTRACT

Cytoadherence of Plasmodium falciparum‐infected red blood cells (IRBCs) on human microvascular endothelium is mediated by synergistic adhesive interactions with different adhesion molecules in vitro. Here, the authors used a unique human/severe combined immunodeficient (SCID) mouse chimeric model to directly visualize IRBC–endothelial interactions in an intact human microvasculature in vivo. Stimulation of human skin grafts with 100 ng TNF‐α for 4 h led to a dramatic reduction in the distance rolled by IRBCs before arrest, so that the majority of IRBCs adhered directly to the endothelium with a 1.8‐fold increase in the number of adherent cells. The decrease in rolling distance and increase in adhesion could be reversed by anti‐ICAM‐1. More importantly, the effect of TNF‐α could be seen only in the presence of CD36. A further increase in adhesion by 4.9‐fold was observed after 24 h of TNF‐α stimulation. The increase could be reversed by anti‐ICAM‐1, but not anti‐VCAM‐1. In histamine‐stimulated grafts, the rolling flux fraction and adhesion increased by 2.8‐ and 1.6‐fold, respectively. The increases were attributable to P‐selectin as an inhibitory anti‐P‐selectin antibody abrogated both the increased rolling flux fraction and firm adhesion. These findings indicate that in addition to CD36, ICAM‐1, and P‐selectin are major contributors to the dynamic process of IRBC adhesion by different mechanisms in vivo.
Logical Foundations of Evidential Support
Authors: Fitelson Branden
Published: August 2007

Carnap's inductive logic (or confirmation) project is revisited from an “increase in firmness” (or probabilistic relevance) point of view. It is argued that Carnap's main desiderata can be satisfied in this setting, without the need for a theory of “logical probability.” The emphasis here will be on explaining how Carnap's epistemological desiderata for inductive logic will need to be modified in this new setting. The key move is to abandon Carnap's goal of bridging confirmation andcredence, in favor of bridging confirmation andevidential support.