bluuebunny/crossref_metadata_2025 huggingface dataset:
Click chemistry in materials synthesis. 1. Adhesive polymers from copper‐catalyzed azide‐alkyne cycloaddition
Authors: Díaz David D. , Punna Sreenivas , Holzer Philipp , McPherson Andrew K. , Sharpless K. Barry , Fokin Valery V. , Finn M. G.
Published: July 2004

The copper(I)‐catalyzed cycloaddition reaction between azides and alkynes has been employed to make metal‐adhesive materials. Copper and brass surfaces supply the necessary catalytic Cu ions, and thus the polymerization process occurs selectively on these metals in the absence of added catalysts. Alternatively, copper compounds can be added to monomer mixtures and then introduced to reducing metal surfaces such as zinc to initiate polymerization. The resulting materials were found to possess comparable or superior adhesive strength to standard commercial glues, and structure‐activity correlations have identified several important properties of the monomers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4392–4403, 2004
Thermodynamic interactions in blends of poly(4‐tert‐butyl styrene) and polyisoprene by small‐angle neutron scattering
Authors: Yurekli Koray , Krishnamoorti Ramanan
Published: July 2004

The thermodynamic interactions between poly(4‐tert‐butyl styrene) [P(4tBS)] and 1,4‐polyisoprene (PI; both hydrogenous) were obtained as functions of the temperature, PI molecular weight, and blend composition through the examination of miscible ternary blends of these two components with a common miscible labeled polymer [90% 1,2‐deuterated polybutadiene (dPBD)] with small‐angle neutron scattering. The thermodynamic interaction parameters between P(4tBS) and dPBD and between P(4tBS) and PI increased with increasing temperature and were consistent with lower critical solution temperature behavior. Although the binary blends of P(4tBS) and dPBD exhibited phase separation at elevated temperatures, the thermodynamic interaction parameters between P(4tBS) and PI remained large and negative and independent of the PI molecular weight. Finally, the thermodynamic interactions for PI and P(4tBS) depended strongly on the ratio of PI to P(4tBS) and were also sensitive to the amount of dPBD present in the ternary blend. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3204–3217, 2004
Transformation of phase size distribution into scattering intensity
Authors: Bauer Barry J.
Published: July 2004

A practical method of calculating the small‐angle scattering intensity and the density correlation function from the phase size distribution is presented for a sample with a random two‐phase morphology. The correlation function can be calculated in terms of joint probability distribution functions of the phase size distributions of the two individual phases with information from the chord length distribution. The phase size distribution is approximated as a weighted sum of exponentials, which is then transformed analytically into the correlation function and hence the small‐angle scattering for any combination of phase size distributions of the two phases. This represents an extension of the Debye method for materials with more complex phase size distributions. The inverse problem of calculating the phase size distributions from the small‐angle scattering requires a thermodynamic model or simplifying approximation. An example of the reverse transformation is given for a nanoporous polymer thin film. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3070–3080, 2004
Polymer dynamics in hydrogenous systems by neutron reflectivity
Authors: Esker A. R. , Grüll H. , Satija S. K. , Han C. C.
Published: July 2004

Neutron reflectivity is a powerful tool for exploring polymer dynamics above the glass‐transition temperature at short diffusion times in layered thin‐film systems. Recent studies of membrane‐mediated interdiffusion in deuterium‐labeled systems have shown that ultrathin membranes can track the position of the interface in binary polymeric diffusion couples and also can discriminate between perdeuterated and hydrogenous polymers of the same molecular weight. This report shows that similar dynamic information can be obtained for binary hydrogenous polystyrene (hPS) diffusion couples separated by an ultrathin (6‐nm) isopentylcellulose cinnamate (IPCC) membrane on Si wafers (air//hPS/IPCC/hPS//Si, where “//” represents an interface between obviously different phases and “/” represents a dynamic interface between polymeric species). In particular, the air//hPS/IPCC/hPS//Si system provides the same information as perdeuterium‐labeled polystyrene (dPS) diffusion couples separated by the same IPCC membrane (air//dPS/IPCC/dPS//Si). This technique has potential applications for the study of confinement effects on thin‐film dynamics and macromolecular transport across membranes. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3248–3257, 2004
Effect of random and block copolymer additives on a homopolymer blend studied by small‐angle neutron scattering
Authors: Voge Gretchen , Fosser Kari , Waldow Dean , Briber Robert , Halasa Adel
Published: July 2004

Small‐angle neutron scattering (SANS) has been employed to study a blend of polystyrene and polybutadiene modified by copolymer additives. SANS data from the one‐phase region approaching the phase boundary has been acquired for blends modified by random and diblock copolymers that have equal amounts of styrene and butadiene monomers as well as a random copolymer with an unequal monomer composition. The binary blend is near the critical composition, and the copolymer concentrations are low at 2.5% (w/w). The data have been fitted with the random‐phase approximation model (binary and multicomponent versions) to obtain Flory–Huggins interaction parameters (χ) for the various monomer interactions. These results are considered in the context of previous light scattering data for the same blend systems. The SANS cloud points are in good agreement with previous results from light scattering. The shifts in the phase boundary are due to the effects of the additives on the χ parameter at the spinodal. All the additives appear to lower the χ parameter between the homopolymers; this is in conflict with the predicted Flory–Huggins behavior. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3191–3203, 2004
Dominance hierarchy in a herd of female eland antelope (Taurotragus oryx) in captivity
Authors: Wirtu G. , Pope C.E. , Vaccaro J. , Sarrat E. , Cole A. , Godke R.A. , Dresser B.L.
Published: July 2004

The dominance hierarchy of a group of adult female elands (n=10) kept in captivity was followed for 34 months. Outcomes of dominance relationships at the beginning and end of the study were compared. A clear dominance hierarchy existed in the herd. The dominance pattern was complex, but triads were predominantly (95%) transitive or linear. Reversal of dominance occurred in 12 dyads (27%), of which eight (67%) involved a single female. Two females shared the most dominant rank at the beginning of the study. One of these two females and another female later assumed the highest dominance rank on different occasions. A single female remained most subordinate throughout the study period. The correlation between body weight and dominance rank was not significant (r=0.46; P=0.21). Similarly, dominance rank was not associated with the taming potential of the females. However, the median dominance value increased in females with good taming potential, while it decreased in those with poor taming potential. In conclusion, captive eland antelope have a dynamic and complex dominance hierarchy that is predominantly linear. Zoo Biol 23:323–333, 2004. © 2004 Wiley‐Liss, Inc.
Thermal characteristics of wild and captive Micronesian kingfisher nesting habitats
Authors: Kesler Dylan C. , Haig Susan M.
Published: July 2004

To provide information for managing the captive population of endangered Guam Micronesian kingfishers (Halcyon cinnamomina cinnamomina), four biologically relevant thermal metrics were compared among captive facilities on the United States mainland and habitats used by wild Micronesian kingfishers on the island of Pohnpei (H. c. reichenbachii), Federated States of Micronesia. Additionally, aviaries where kingfishers laid eggs were compared to those in which birds did not attempt to breed. Compared to aviaries, habitats used by wild Pohnpei kingfishers had 3.2°C higher daily maximum and minimum temperatures and the proportion of time when temperatures were in the birds' thermoneutral zone was 45% greater. No differences were found in the magnitude of temperature fluctuation in captive and wild environments. In captive environments in which birds bred, daily maximum temperatures were 2.1°C higher and temperatures were within the thermoneutral zone 25% more often than in the aviaries where the kingfishers did not breed. No differences were found in the magnitude of temperature fluctuation or the daily minimum temperature. Results suggest that the thermal environment has the potential to influence reproduction, and that consideration should be given to increasing temperatures in captive breeding facilities to improve propagation of the endangered Micronesian kingfisher. Zoo Biol 23:301–308, 2004. Published 2004 Wiley‐Liss, Inc.
Calculation of longevity and life expectancy in captive elephants
Authors: Wiese Robert J. , Willis Kevin
Published: July 2004

The concepts of longevity (longest lived) and life expectancy (typical age at death) are common demographic parameters that provide insight into a population. Defined as the longest lived individual, longevity is easily calculated but is not representative, as only one individual will live to this extreme. Longevity records for North American Asian elephants (Elephas maximus) and African elephants (Loxodonta africana) have not yet been set, as the oldest individuals (77 and 53 years, respectively) are still alive. One Asian elephant lived to 86 years in the Taipei Zoo. This is comparable to the maximum (though not typical) longevity estimated in wild populations. Calculation of life expectancy, however, must use statistics that are appropriate for the data available, the distribution of the data, and the species' biology. Using a simple arithmetic mean to describe the non‐normally distributed age at death for elephant populations underestimates life expectancy. Use of life‐table analysis to estimate median survivorship or survival analysis to estimate average survivorship are more appropriate for the species' biology and the data available, and provide more accurate estimates. Using a life‐table, the median life expectancy for female Asian elephants (Lx=0.50) is 35.9 years in North America and 41.9 years in Europe. Survival analysis estimates of average life expectancy for Asian elephants are 47.6 years in Europe and 44.8 years in North America. Survival analysis estimates for African elephants are less robust due to less data. Currently the African elephant average life expectancy estimate in North America is 33.0 years, but this is likely to increase with more data, as it has over the past 10 years. Zoo Biol 23:365–373, 2004. © 2004 Wiley‐Liss, Inc.
A comparison of responses by three broadband radiometers to different ultraviolet‐B sources
Authors: Gehrmann W.H. , Horner J.D. , Ferguson G.W. , Chen T.C. , Holick M.F.
Published: July 2004

Three types of broadband ultraviolet‐B (UVB) radiometers were shown to display different irradiances from the same light source. Also, natural light and different lamp types were shown to have different vitamin D–synthesizing potential. Equations relating the irradiance readings from UVB radiometers from Gigahertz‐Optik Inc., UVP Inc., and Spectronics Corp. to in vitro vitamin D–synthesizing potential are reported for four UVB sources. Zoo Biol 23:355–363, 2004. © 2004 Wiley‐Liss, Inc.
Comparison of fecal storage methods for steroid analysis in black rhinoceroses (Diceros bicornis)
Authors: Galama Wieke T. , Graham Laura H. , Savage Anne
Published: July 2004

Many field studies and conservation programs for wildlife species include noninvasive endocrine monitoring of gonadal function. Freezing fecal samples immediately after collection until further analysis is often not a viable option for researchers in remote areas. Phase 1 of this study was designed to compare different methods of preserving fecal samples over several time periods (30, 90, or 180 days) in order to determine which method provided the most accurate and reliable technique for measuring fecal progestagens. Fecal samples were collected from two female black rhinoceroses (Diceros bicornis) housed at Disney's Animal Kingdom, Lake Buena Vista, FL. We compared three storage methods: 1) storing fecal samples without processing or preservatives (untreated), 2) storing an aliquot of fecal sample in 80% methanol (MeOH), and 3) drying the fecal sample in a solar box cooker prior to storage. Control samples (day 0) were collected and extracted, and then stored at −20°C until they were analyzed. Phase 2 of the study was designed to examine the effects of long‐term storage (up to 180 days) on fecal progestagen profiles that reflect reproductive activity (pregnancy and estrous cycles). In samples obtained from a pregnant female and stored for 30 days, there were no significant differences in fecal progestagen concentrations between the three treatment conditions. However, the mean concentrations of progestagens (± SE) in untreated samples increased significantly from 8.3 ± 0.3 µg/g wet weight feces at day 0 to 17.7 ± 5.1 µg/g feces at day 90, and 17.8 ± 4.7 µg/g feces at day 180. Samples that were collected from a pregnant female and stored in 80% MeOH or dried in the solar box correlated with controls (r=0.86 and 0.87, respectively; P<0.05) at day 180. In contrast, samples that were stored without preservatives for 180 days did not correlate with controls (r=0.35, P>0.05). Progestagen concentrations from samples of the estrous cycling female showed similar results. In conclusion, fecal samples dried in a solar box cooker or stored in 80% MeOH maintained absolute and relative progestagen concentrations for at least 180 days when they were stored outdoors and exposed to the climatic conditions of central Florida. Both methods can have significant applications for the study of reproductive events in areas where access to electricity is limited. Zoo Biol 23:291–300, 2004. © 2004 Wiley‐Liss, Inc.
ERα and STAT5a cross‐talk: interaction through C‐terminal portions of the proteins decreases STAT5a phosphorylation, nuclear translocation and DNA‐binding
Authors: Wang Ying , Cheng Christopher H.K
Published: July 2004

Cross‐talk between ERα and STAT5a was demonstrated to mediate through a direct physical association between the two proteins. By GST pull‐down assays and functional assays with various constructs of ERα and STAT5a, it was shown that the C‐termini of these two proteins were mainly responsible for this interaction. Furthermore, the interaction between ERα and STAT5a was demonstrated to give rise to functional changes in their signaling events. In cell transfection studies, it was shown that ERα activation could attenuate PRLR signaling through STAT5a. This ERα‐mediated attenuation of PRLR signaling was substantiated by observed decreases in the phosphorylation of JAK2 and STAT5a, reduced translocation of STAT5a into the nucleus, and reduced binding of STAT5a onto a GAS‐containing nucleotide. Apart from transfected cells, the interaction between ERα and STAT5a could also be observed in established breast cancer cell lines of MCF‐7 and T‐47D in co‐immunoprecipitation studies. However, the functional consequence of the interaction in these cancer cells was very different from the transfected HEK293 cells. ER activation could lead to potentiation of PRLR signaling in MCF‐7 cells but not in T‐47D cells. Conversely, in both MCF‐7 and T‐47D cells, PRLR activation could lead to attenuation of ER signaling. These data serve to elucidate the mechanisms underlying the ERα–STAT5a cross‐talk and in demonstrating that the functional consequence of this cross‐talk depends on the precise milieus of the intracellular environment.
Modification of serine 392 is a critical event in the regulation of p53 nuclear export and stability
Authors: Kim Young-Youl , Park Bum-Joon , Kim Dong-Joon , Kim Woo-Hyang , Kim Soonhag , Oh Kyung-Soo , Lim Joong-Yeon , Kim Joon , Park Chan , Park Sang-Ick
Published: July 2004

Although it has been shown that phosphorylations of p53 serine its residues are critical events for the regulation of their function, the specific biological effects of each of these phosphorylations, especially at serine 392, remain to be elucidated. Serine 392 has been proposed to play a role in the tetramerization of p53 and in the enhancement of its DNA‐binding affinity. However, this is not consistent with other reports showing that substitution of serine 392 does not disrupt p53 function. These discrepancies suggest that modification of serine 392 may contribute to p53 activity through other transactivating pathways. In this study, we demonstrate that this C‐terminal serine residue (p53‐392S) in fact plays a critical role in the regulation of p53 stability such that substitution with alanine (p53‐392A) strongly enhances p53 stability without disrupting mouse double minute 2 binding. Additionally, the p53‐392A mutant is localized mainly in the nucleus, whereas both wild‐type p53 and a glutamic acid mutant, p53‐392E, are evenly distributed throughout the cytoplasm and nucleus. However, each of these p53 species had similar effects on both cell cycle inhibition and apoptosis, in response to either UV or adriamycin treatment. Moreover, p53‐392A protein was resistant to E6‐mediated degradation. Our results suggest that although serine 392 is not essential for the transactivation and nuclear import of p53, it exerts important effects upon p53 stability via the inhibition of its nuclear export mechanism.
Nanosecond pulsed electric fields perturb membrane phospholipids in T lymphoblasts
Authors: Vernier P.Thomas , Sun Yinghua , Marcu Laura , Craft Cheryl M. , Gundersen Martin A.
Published: July 2004

Nanosecond, megavolt‐per‐meter pulsed electric fields scramble the asymmetric arrangement of phospholipids in cell membranes without the permeabilization associated with longer, lower‐field pulses. A single 30 ns, 2.5 MV/m pulse produces perturbations consistent with phosphatidylserine (PS) externalization in Jurkat T lymphoblasts within milliseconds, polarized in the direction of the applied field, indicating an immediate interaction between membrane components and the electric field. This disturbance occurs only at the anode pole of the cell, supporting the hypothesis that the pulsed field drives the negatively charged PS head group toward the positive electrode, directly providing the energy for crossing the membrane dielectric barrier.
Frataxin overexpressing mice
Authors: Miranda Carlos J , Santos Manuela M , Ohshima Keiichi , Tessaro Marco , Sequeiros Jorge , Pandolfo Massimo
Published: July 2004

Friedreich ataxia, the most common autosomal recessive ataxia, is caused by frataxin deficiency. Reduction of frataxin has been associated with iron accumulation and sensitivity to iron induced oxidative stress. To better understand the function of frataxin, transgenic mice (tgFxn) overexpressing human frataxin were generated. Iron metabolism parameters in tgFxn were normal and no signs of ataxia or other obvious abnormalities were observed, indicating that overexpression of frataxin in mouse is innocuous. Several hypotheses for frataxin function were evaluated in tgFxn mice. In particular, we observed that TgFxn mice show an altered response during hematopoietic differentiation, suggesting that frataxin may directly affect heme synthesis.
β‐Dystroglycan can be revealed in microsomes from mdx mouse muscle by detergent treatment
Authors: Cluchague Nicolas , Moreau Céline , Rocher Chantal , Pottier Sandrine , Leray Geneviève , Cherel Yan , Le Rumeur Elisabeth
Published: July 2004

β‐Dystroglycan is the central member of a transmembrane protein complex of the skeletal muscle plasma membrane. Since it was not detected in dystrophin‐deficient skeletal muscles, a disruption of the complex was thought to be involved in the dystrophic process. We report here that β‐dystroglycan is actually present at normal levels in mdx mouse muscle plasma membrane: treatment with cholate detergent is able to reveal its presence by SDS–PAGE and immunoblotting. This result shows that, in dystrophin‐deficient muscles, β‐dystroglycan is indeed targeted to the plasma membrane but remains inaccessible to classical solubilizing treatments and to antibodies used for immunolocalization.
Daily injection of insulin attenuated impairment of liver circadian clock oscillation in the streptozotocin‐treated diabetic mouse
Authors: Kuriyama Koji , Sasahara Kei , Kudo Takashi , Shibata Shigenobu
Published: July 2004

Recent studies have shown a dampened amplitude of clock gene rhythm in the heart and liver of streptozotocin (STZ)‐treated rats and mice, however it is unknown whether impairment is due to dysfunction of the suprachiasmatic nucleus (SCN) or not. Rhythmic expression of mPER2 was dampened in the STZ‐treated mouse liver but not SCN and cerebral cortex. Injection of insulin could normalize an impairment of mPer2 and mPER2 expression rhythm in the liver, when it was injected at nighttime, but not at daytime. In the present study, we demonstrated that insulin‐dependent diabetes impaired oscillation of the peripheral clock gene and its product. Insulin injection can recover dampened oscillation of the peripheral clock depending on its injection time.
Cohesin–dockerin interaction in cellulosome assembly: a single Asp‐to‐Asn mutation disrupts high‐affinity cohesin–dockerin binding
Authors: Handelsman Tal , Barak Yoav , Nakar David , Mechaly Adva , Lamed Raphael , Shoham Yuval , Bayer Edward A
Published: July 2004

The cohesive cellulosome complex is sustained by the high‐affinity cohesin–dockerin interaction. In previous work [J. Biol. Chem. 276 (2001) 9883], we demonstrated that a single Thr‐to‐Leu replacement in the Clostridium thermocellum dockerin component differentiates between non‐recognition and high‐affinity recognition by the interspecies rival cohesin from C. cellulolyticum. In this report, we show that a single Asp‐to‐Asn substitution on the cohesin counterpart also disrupts normal recognition of the dockerin. The Asp34 carboxyl group of the cohesin appears to play a central role in the resultant hydrogen‐bonding network as an acceptor of two crucial hydrogen bonds from Ser45 of the dockerin domain. The results underscore the fragile nature of the intermolecular contact interactions that maintain this very high‐affinity protein–protein interaction.
Functional role of the C‐terminus of voltage‐gated sodium channel Nav1.8
Authors: Choi Jin-Sung , Tyrrell Lynda , Waxman Stephen G , Dib-Hajj Sulayman D
Published: July 2004

Sodium channel Nav1.8 requires stronger depolarization than other sodium channels for activation and inactivation. The contribution of Nav1.8 C‐terminus to this property was investigated by producing Nav1.8 and Nav1.4 chimeras and expressing them in ND7/23 cells. Current densities of the chimeras were significantly different than in parental channels, and the voltage‐dependence of activation was depolarized in Nav1.4/1.8C compared to Nav1.4. Analysis of steady‐state inactivation showed that only Nav1.8 and Nav1.4/1.8C currents demonstrate a non‐inactivated fraction. Thus, the C‐terminus of Nav1.8 contributes to regulation of channel density at the cell surface, modulates channel gating, and regulates the generation of sustained current.
Long‐horizon abnormal performance following rights issues and placings: Additional evidence from the U.K. market
Authors: Ho Keng‐Yu
Published: July 2004

We revisit the long‐horizon abnormal performance of U.K. firms following rights issues and placings over the period 1989–1997. We make the following contributions relative to prior research. First, we use, as far as we are aware, a more comprehensive data set of rights issues and placings than hitherto studied for the U.K. market. We thus exploit the fact that issuing new equity predominantly through rights issues is a feature of the U.K. equity market that differs from the U.S. and other markets, where public offers dominate seasoned equity issues. Second, we study both the pre‐ and post‐offer long‐horizon performance, complementing previous research that focuses only on announcement‐day wealth effects. Third, we apply various metrics and revisit the evidence of long‐horizon post‐offer underperformance reported in previous research. We find, however, little evidence of long‐horizon post‐offer underperformance for U.K. firms following issues of equity through rights issues or by placings.
Regional tectonic stress near the San Andreas fault in central and southern California
Authors: Townend J. , Zoback M. D.
Published: July 2004

Throughout central and southern California, a uniform NNE‐SSW direction of maximum horizontal compressive stress is observed that is remarkably consistent with the superposition of stresses arising from lateral variations in lithospheric buoyancy in the western United States, and far‐field Pacific‐North America plate interaction. In central California, the axis of maximum horizontal compressive stress lies at a high angle to the San Andreas fault (SAF). Despite relatively few observations near (±10 km) the fault, observations in the greater San Francisco Bay area indicate an angle of as much as 85°, implying extremely low fault strength. In southern California, observations of stress orientations near the SAF are rotated slightly counter‐clockwise with respect to the regional field. Nevertheless, we observe an approximately constant angle between the SAF and the maximum horizontal stress direction of 68 ± 7° along ∼400 km of the fault, indicating that the SAF has moderately low frictional strength in southern California.
Stress‐induced seismic velocity anisotropy and physical properties in the SAFOD Pilot Hole in Parkfield, CA
Authors: Boness Naomi L. , Zoback Mark D.
Published: July 2004

A comprehensive suite of geophysical logs was collected in the SAFOD Pilot Hole from a depth of 775 m to 2150 m in highly fractured Salinian granite. The Pilot Hole intersected numerous macroscopic fractures and faults with extremely varied orientations. Despite the highly variable orientation of the fractures and faults, the fast polarization direction of the shear waves is very consistent with the direction of maximum horizontal compression determined from wellbore breakouts and drilling induced tensile fractures. At least three major shear zones were intersected by the borehole that are characterized by anomalously low velocity and resistivity, anomalously high shear velocity anisotropy and an absence of stress‐induced wellbore breakouts (which suggests anomalously low differential stress). We argue that the physical mechanism responsible for the seismic velocity anisotropy observed in the Pilot Hole is the preferential closure of fractures in response to an anisotropic stress state.
Accommodation of Arabia‐Eurasia convergence in the Zagros‐Makran transfer zone, SE Iran: A transition between collision and subduction through a young deforming system
Authors: Regard V. , Bellier O. , Thomas J.‐C. , Abbassi M. R. , Mercier J. , Shabanian E. , Feghhi K. , Soleymani S.
Published: July 2004

At Iranian longitude, the Arabian plate is moving northward relative to Eurasia (∼20 mm yr−1 according to GPS). To the east, this relative motion is accommodated by northward subduction under the E‐W Makran emerged accretionary prism. To the west, it is accommodated partly by the Zagros fold‐and‐thrust belt and partly by the Alborz/Kopet Dagh deforming zones further north. This work investigates the NNW striking transition zone that connects Zagros and Makran: the Minab‐Zendan fault system. Satellite images, and structural and geomorphic field observations show a distributed deformation pattern covering a wide domain. Five north to NW trending major faults were identified. They exhibit evidence for late Quaternary reverse right‐lateral slip, and correspond to two distinct fault systems: the western one transferring the Zagros deformation to the Makran prism, and the eastern one northward transferring the deformation to the Alborz/Kopet Dagh. Tectonic study and fault slip vector analyses indicate that two distinct tectonic regimes have occurred successively since the Miocene within a consistent regional NE trending compression: (1) an upper Miocene to Pliocene tectonic regime characterized by partitioned deformation, between reverse faulting and en echelon folding; (2) a NE trending σ1 axis transpressional regime homogeneously affecting the region since upper Pliocene. The change is contemporaneous with major tectonic reorganization regionally recorded. Therefore this study provides evidence for active deformation that is not localized, but distributed across a wide zone. It accommodates the convergence and transfers it from collision to subduction by transpressional tectonics without any partitioning process in the present‐day period.
A framework for estimating the transaction costs of alternative mechanisms for water exchange and allocation
Authors: McCann Laura , Easter K. William
Published: July 2004

Alternative mechanisms for water transfers will differ in the types of transaction costs incurred as well as their magnitudes and incidence. This article presents a framework for including transaction costs as well as transfer costs in the evaluation of alternative mechanisms. The work on measurement of transaction costs associated with water markets has underestimated these costs by only focusing on the costs incurred once a market exists. The framework presented here also includes the costs associated with the development of a market mechanism. Once the appropriate framework has been developed, there are a number of measurement issues involved with incorporating transaction costs in the overall assessment of the efficiency of water allocation mechanisms. While the costs involved with the final transaction are relatively easy to measure, those involved with the initial information gathering, policy enactment, and design and implementation of a formal market mechanism are rarely documented. Similarly, it is much easier to measure transaction costs after the policy is implemented; however, it is necessary to predict costs to inform decision‐making and improve policy design.
Market prices for water in the semiarid West of the United States
Authors: Brookshire David S. , Colby Bonnie , Ewers Mary , Ganderton Philip T.
Published: July 2004

Market prices contain information about supply and demand, the institutions that influence both these elements, and the operation of the market. Prices also allocate scarce resources to higher‐valued uses. In this paper we analyze the price history of three water markets in the arid Southwest: Arizona's Central Arizona Project, Colorado's Colorado Big Thompson Project, and New Mexico's Middle Rio Grande Conservancy District. Using water transfers over 11 years, we estimate a simultaneous system of market equations, one for price and the other for quantity demanded. Comparison of the institutional characteristics of each market reveals that Colorado's market is well developed, with many trades and rising prices that respond to market conditions, and New Mexico's market is developing well, with lower prices, but showing some response to supply and demand factors. Arizona's market is the least developed, with few trades and very low prices. Our empirical findings support our claim that markets are becoming more efficient in these regions despite the considerable institutional and historical impediments to the evolution of water markets.
A mechanical model of the San Andreas fault and SAFOD Pilot Hole stress measurements
Authors: Chéry Jean , Zoback Mark D. , Hickman Stephen
Published: July 2004

Stress measurements made in the SAFOD pilot hole provide an opportunity to study the relation between crustal stress outside the fault zone and the stress state within it using an integrated mechanical model of a transform fault loaded in transpression. The results of this modeling indicate that only a fault model in which the effective friction is very low (<0.1) through the seismogenic thickness of the crust is capable of matching stress measurements made in both the far field and in the SAFOD pilot hole. The stress rotation measured with depth in the SAFOD pilot hole (∼28°) appears to be a typical feature of a weak fault embedded in a strong crust and a weak upper mantle with laterally variable heat flow, although our best model predicts less rotation (15°) than observed. Stress magnitudes predicted by our model within the fault zone indicate low shear stress on planes parallel to the fault but a very anomalous mean stress, approximately twice the lithostatic stress.
Accuracy of the Lightning Mapping Array
Authors: Thomas Ronald J. , Krehbiel Paul R. , Rison William , Hunyady Steven J. , Winn William P. , Hamlin Timothy , Harlin Jeremiah
Published: July 2004

The location accuracy of the New Mexico Tech Lightning Mapping Array (LMA) has been investigated experimentally using sounding balloon measurements, airplane tracks, and observations of distant storms. We have also developed simple geometric models for estimating the location uncertainty of sources both over and outside the network. The model results are found to be a good estimator of the observed errors and also agree with covariance estimates of the location uncertainties obtained from the least squares solution technique. Sources over the network are located with an uncertainty of 6–12 m rms in the horizontal and 20–30 m rms in the vertical. This corresponds well with the uncertainties of the arrival time measurements, determined from the distribution of chi‐square values to be 40–50 ns rms. Outside the network the location uncertainties increase with distance. The geometric model shows that the range and altitude errors increase as the range squared, r2, while the azimuthal error increases linearly with r. For the 13 station, 70 km diameter network deployed during STEPS the range and height errors of distant sources were comparable to each other, while the azimuthal errors were much smaller. The difference in the range and azimuth errors causes distant storms to be elongated radially in plan views of the observations. The overall results are shown to agree well with hyperbolic formulations of time of arrival measurements [e.g., Proctor, 1971]. Two appendices describe (1) the basic operation of the LMA and the detailed manner in which its measurements are processed and (2) the effect of systematic errors on lightning observations. The latter provides an alternative explanation for the systematic height errors found by Boccippio et al. [2001] in distant storm data from the Lightning Detection and Ranging system at Kennedy Space Center.
On Lagrangian time scales and particle dispersion modeling in equilibrium turbulent shear flows
Authors: Oesterlé Benoit , Zaichik Leonid I.
Published: July 2004

As intermediate quantities available from various existing numerical computations, the fluid Lagrangian time scales are of primary importance in the development of probability density function models for turbulent flows. Similarly, the time scales of the fluid seen by discrete particles in two-phase flows are essential for the development of dispersion models based on stochastic differential equations. Such time scales are obviously depending not only on the particle properties but also on the fluid Lagrangian and Eulerian time scales. A model is proposed here to estimate the directional dependence of the fluid Lagrangian time scales and drift coefficients in one-directional equilibrium turbulent shear flows, based on a local homogeneity assumption in the frame of the generalized Langevin model. Through comparison with available direct and large eddy simulation predictions in channel flows and in a homogeneous shear flow, the model is shown to lead to significant improvements in the streamwise and spanwise directions, where the existing empirical laws for the Lagrangian time scales are far from being satisfactory. We examine the way this model can be used to build a suitable stochastic process for the fluid seen by inertial particles in such basic turbulent shear flows.
Development of a measurement system of OH reactivity in the atmosphere by using a laser-induced pump and probe technique
Authors: Sadanaga Yasuhiro , Yoshino Ayako , Watanabe Keisuke , Yoshioka Atsushi , Wakazono Yoko , Kanaya Yugo , Kajii Yoshizumi
Published: July 2004

A novel instrument for measuring OH reactivity in the troposphere has been developed by using a laser-induced pump and probe technique. Air was introduced into a flow tube and OH was produced artificially using O3 photolysis by 266 nm laser. The OH decay rate in the flow tube was monitored by the time-resolved laser-induced fluorescence technique. In this article, the instrument, that is, the measurement principle, the flow tube and the fluorescence detection cell, is presented in detail. Interference by absorption of the 266 nm laser light by O3, and photolysis of NO2 and HCHO was found to be negligible. The influence of recycled OH from the HO2+NO reaction on the measured OH reactivity was estimated by a box model calculation. The systematic error of the measured decay rate was found to be less than 5% even in high NO condition ([NO]=20 ppbv). The dependence of the measured decay rate on the flow rate in the reaction tube was investigated. A slight change in the total flow rate does not influence the measured decay rate in our experimental condition. The second-order rate coefficients of the OH+CO reactions were measured in order to confirm the accuracy of the measured OH decay rate. The measured rate coefficients were agreed excellently with the recent recommended values. The results of observations in our institute are briefly presented.
Electrostatic perturbations in partially ionized plasma with the effects of ionization and recombination
Authors: Vranjes J. , Tanaka M. Y. , Kono M. , Poedts S.
Published: July 2004

The behavior of the electrostatic ion acoustic mode in a partially ionized plasma is studied in the presence of collisions which involve processes of ionization and recombination, taking into account the dynamics of the neutrals caused by elastic and inelastic collisions with ions. The application of the model to space plasmas, which are usually subject to gravity, is discussed in detail. A dispersion equation which includes the effects of ionization and recombination is derived and the stability/instability conditions are discussed. Parameters applicable to a region of the upper solar chromosphere are used and the increment of the ion sound wave is calculated yielding an unstable ion sound wave for wavelengths larger than 20 km.
Single sideband modulator, a key component of Tore-Supra heterodyne reflectometers
Authors: Sabot R. , Bottereau C. , Chareau J.-M. , Clairet F. , Paume M.
Published: July 2004

Although single sideband modulation offers a simple solution to active heterodyne devices and is common in devices working over 150 GHz, it has been scarcely used for reflectometers. For a few years, large bandwidth (12–20 GHz), high performance single sideband modulators (SSBM) have been available. For higher frequency application, a sideband rejection around −25 dBc seems necessary to ensure that the image sideband amplitude remains low after a frequency multiplier. A SSBM provided by Miteq Company presents high enough rejection levels to be assembled with frequency multipliers. Based on this SSBM, we developed a simple microwave scheme suitable for all Tore-Supra reflectometers—from 50 to 155 GHz, dedicated either to density profile reconstruction or to density fluctuation measurements. Compared to the double sideband modulator previously used, SSBM offers higher signal to noise ratio and enables fixed frequency measurements, paving the way for new measurement techniques.
A simple three-channel dc SQUID system using time domain multiplexing
Authors: Mück M. , Korn M. , Mugford C. G. A , Kycia J. B.
Published: July 2004

Conventional multichannel superconducting quantum interference device (SQUID) systems require a SQUID read-out circuit for each channel, as well as many wires connecting each individual SQUID and feedback coil to the room temperature electronics. We present a simple time domain multiplexed read-out scheme which requires only a single SQUID read-out circuit that is successively switched between all the SQUIDs. By connecting all the SQUIDs and all the feedback coils in series, this time domain multiplexed system requires many fewer wires between the SQUIDs and the room temperature read-out circuit than other multichannel systems.
Rad6-Bre1-mediated histone H2B ubiquitylation modulates the formation of double-strand breaks during meiosis
Authors: Yamashita Kentaro , Shinohara Miki , Shinohara Akira
Published: July 2004

An E2 ubiquitin-conjugating enzyme, Rad6, working with an E3 ubiquitin ligase Bre1, catalyzes monoubiquitylation of histone H2B on a C-terminal lysine residue. The
rad6
mutant of
Saccharomyces cerevisiae
shows a meiotic prophase arrest. Here, we analyzed meiotic defects of a
rad6
null mutant of budding yeast. The
rad6
mutant exhibits pleiotropic phenotypes during meiosis.
RAD6
is required for efficient formation of double-strand breaks (DSBs) at meiotic recombination hotspots, which is catalyzed by Spo11. The mutation decreases overall frequencies of DSBs in a cell. The effect of the
rad6
mutation is local along chromosomes; levels of DSBs at stronger hotspots are particularly reduced in the mutant. The absence of
RAD6
has little effect on the formation of ectopic DSBs targeted by Spo11 fusion protein with a Gal4 DNA-binding domain. Furthermore, the disruption of the
BRE1
as well as substitution of the ubiquitylation site of histone H2B also reduces some DSB formation similar to the
rad6
. These results suggest that Rad6-Bre1, through ubiquitylation of histone H2B, is necessary for efficient recruitment and/or stabilization of a DSB-forming machinery containing Spo11. Histone tail modifications might play a role in DSB formation during meiosis.
Prospects for total synthesis: A vision for a totally synthetic vaccine targeting epithelial tumors
Authors: Keding Stacy J. , Danishefsky Samuel J.
Published: July 2004

Vaccines derived from totally synthetic carbohydrate antigens have been shown to elicit an immune response in both preclinical and clinical settings. The vaccines have been proven safe when administered in human clinical trials and are also competent at inducing antibodies that react with aberrant cells expressing the corresponding carbohydrate antigen. The most well studied vaccines have hitherto focused on single carbohydrate antigens, notwithstanding the known heterogeneity of transformed cells. Advances in synthetic organic chemistry have enabled the preparation and subsequent investigation of vaccines that contain several different tumor-associated carbohydrate antigens in a single molecule. These unimolecular constructs could, in principle, serve as superior mimics of cell surface antigens and hence, as multifaceted cancer vaccines. We report here the synthesis of a pentameric vaccine targeting a specific cancer. The new vaccine contains prostate tumor-associated antigens, Tn, TF, STn, Lewisy, and Globo-H. To reach our goal, antigen-containing amino acid monomers were assembled in a linear fashion to form a glycopeptide containing the five distinct carbohydrate antigen units. The attachment of a linker to the glycopeptide followed by an extraordinary global deprotection and subsequent conjugation to two different immunogenic carriers, keyhole limpet hemocyanin andN-α-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-l-cysteine, resulted in the vaccine constructs. The results described herein indicate that complex unimolecular multivalent vaccines can be efficiently produced in the laboratory. These fully synthetic vaccines have the potential to stimulate a multifaceted immune response against prostate cancer.
Glucocorticoid receptor overexpression in forebrain: A mouse model of increased emotional lability
Authors: Wei Qiang , Lu Xin-Yun , Liu Li , Schafer Gwen , Shieh Kun-Ruey , Burke Sharon , Robinson Terry E. , Watson Stanley J. , Seasholtz Audrey F. , Akil Huda
Published: July 2004

The molecular mechanisms that control the range and stability of emotions are unknown, yet this knowledge is critical for understanding mood disorders, especially bipolar illness. Here, we show that the glucocorticoid receptor (GR) modulates these features of emotional responsiveness. We generated transgenic mice overexpressing GR specifically in forebrain. These mice display a significant increase in anxiety-like and depressant-like behaviors relative to wild type. Yet, they are also supersensitive to antidepressants and show enhanced sensitization to cocaine. Thus, mice overexpressing GR in forebrain have a consistently wider than normal range of reactivity in both positive and negative emotionality tests. This phenotype is associated, in specific brain regions, with increased expression of genes relevant to emotionality: corticotropin-releasing hormone, serotonin, norepinephrine and dopamine transporters, and 5-hydroxytryptamine
1A
receptor. Thus, GR overexpression in forebrain causes higher “emotional lability” secondary to a unique pattern of molecular regulation. This finding suggests that natural variations in GR gene expression can contribute to the fine-tuning of emotional stability or lability and may play a role in bipolar disorder.
Efficient construction of the securine A carbon skeleton
Authors: Korakas Peter , Chaffee Stuart , Shotwell J. Brad , Duque Pamela , Wood John L.
Published: July 2004

Securamine A is a structurally intriguing alkaloid possessing a pyrroloindole core joined via a modified isoprene subunit to a functionalized imidazole ring. Recent synthetic efforts in this laboratory have resulted in the efficient construction of key lactone 36, which undergoes tandem azide reduction/ring expansion to macrolactam 37. Macrolactam 37 possesses the complete macrocyclic core of securamine A.
A proteomic approach for the discovery of protease substrates
Authors: Bredemeyer Andrew J. , Lewis Renate M. , Malone James P. , Davis Alan E. , Gross Julia , Townsend R. Reid , Ley Timothy J.
Published: July 2004

Standardized, comprehensive platforms for the discovery of protease substrates have been extremely difficult to create. Screens for protease specificity are now frequently based on the cleavage patterns of peptide substrates, which contain small recognition motifs that are required for the cleavage of the scissile bond within an active site. However, these studies do not identify
in vivo
substrates, nor can they lead to the definition of the macromolecular features that account for the biological specificity of proteases. To use properly folded proteins in a proteomic screen for protease substrates, we used 2D difference gel electrophoresis and tandem MS to identify substrates of an apoptosis-inducing protease, granzyme B. We confirmed the cleavage of procaspase-3, one of the key substrates of this enzyme, and identified several substrates that were previously unknown, as well as the cleavage site for one of these substrates. We were also able to observe the kinetics of substrate cleavage and cleavage product accumulation by using the 2D difference gel electrophoresis methodology. “Protease proteomics” may therefore represent an important tool for the discovery of the native substrates of a variety of proteases.