bluuebunny/crossref_metadata_2025 huggingface dataset:
Orb and a long poly(A) tail are required for efficientoskartranslation at the posterior pole of theDrosophilaoocyte
Authors: Castagnetti Stefania , Ephrussi Anne
Published: January 2003

During Drosophila oogenesis, the posterior determinant, Oskar, is tightly localized at the posterior pole of the oocyte. The exclusive accumulation of Oskar at this site is ensured by localization-dependent translation of oskar mRNA: translation of oskar mRNA is repressed during transport and activated upon localization at the posterior cortex. Previous studies have suggested that oskar translation is poly(A)-independent. We show that a long poly(A) tail is required for efficient oskar translation, both in vivo and in vitro, but is not sufficient to overcome BRE-mediated repression. Moreover, we show that accumulation of Oskar activity requires the Drosophila homolog of Cytoplasmic Polyadenylation Element Binding protein (CPEB), Orb. As posterior localization of oskar mRNA is an essential prerequisite for its translation, it was critical to identify an allele of orb that does localize oskar mRNA to the posterior pole of the oocyte. We show that flies bearing the weak mutation orbmel localizeoskar transcripts with a shortened poly(A) that fails to enhanceoskar translation, resulting in reduced Oskar levels and posterior patterning defects. We conclude that Orb-mediated cytoplasmic polyadenylation stimulates oskar translation to achieve the high levels of Oskar protein necessary for posterior patterning and germline differentiation.
Shaping the zebrafish notochord
Authors: Glickman Nathalia S. , Kimmel Charles B. , Jones Martha A. , Adams Richard J.
Published: January 2003

Promptly after the notochord domain is specified in the vertebrate dorsal mesoderm, it undergoes dramatic morphogenesis. Beginning during gastrulation,convergence and extension movements change a squat cellular array into a narrow, elongated one that defines the primary axis of the embryo. Convergence and extension might be coupled by a highly organized cellular intermixing known as mediolateral intercalation behavior (MIB). To learn whether MIB drives early morphogenesis of the zebrafish notochord, we made 4D recordings and quantitatively analyzed both local cellular interactions and global changes in the shape of the dorsal mesodermal field. We show that MIB appears to mediate convergence and can account for extension throughout the dorsal mesoderm. Comparing the notochord and adjacent somitic mesoderm reveals that extension can be regulated separately from convergence. Moreover, mutational analysis shows that extension does not require convergence. Hence, a cellular machine separate from MIB that can drive dorsal mesodermal extension exists in the zebrafish gastrula. The likely redundant control of morphogenesis may provide for plasticity at this critical stage of early development.
Neural crest patterning: autoregulatory and crest-specific elements co-operate forKrox20transcriptional control
Authors: Ghislain Julien , Desmarquet-Trin-Dinh Carole , Gilardi-Hebenstreit Pascale , Charnay Patrick , Frain Monique
Published: January 2003

Neural crest patterning constitutes an important element in the control of the morphogenesis of craniofacial structures. Krox20, a transcription factor gene that plays a critical role in the development of the segmented hindbrain, is expressed in rhombomeres (r) 3 and 5 and in a stream of neural crest cells migrating from r5 toward the third branchial arch. We have investigated the basis of the specific neural crest expression ofKrox20 and identified a cis-acting enhancer element (NCE) located 26 kb upstream of the gene that is conserved between mouse, man and chick and can recapitulate the Krox20 neural crest pattern in transgenic mice. Functional dissection of the enhancer revealed the presence of two conserved Krox20 binding sites mediating direct Krox20 autoregulation in the neural crest. In addition, the enhancer included another essential element containing conserved binding sites for high mobility group (HMG) box proteins and which responded to factors expressed throughout the neural crest. Consistent with this the NCE was strongly activated in vitro by Sox10, a crest-specific HMG box protein, in synergism with Krox20, and the inactivation of Sox10prevented the maintenance of Krox20 expression in the migrating neural crest. These results suggest that the dependency of the enhancer on both crest- (Sox10) and r5- (Krox20) specific factors limits its activity to the r5-derived neural crest. This organisation also suggests a mechanism for the transfer and maintenance of rhombomere-specific gene expression from the hindbrain neuroepithelium to the emerging neural crest and may be of more general significance for neural crest patterning.
Mitochondrial and nucleocytoplasmic targeting of O-linked GlcNAc transferase
Authors: Love Dona C. , Kochran Jarema , Cathey R. Lamont , Shin Sang-Hoon , Hanover John A.
Published: January 2003

O-linked GlcNAc transferase (OGT) mediates a novel glycan-dependent signaling pathway, but the intracellular targeting of OGT is poorly understood. We examined the localization of OGT by immunofluorescence microscopy, subcellular fractionation and immunoblotting using highly specific affinity-purified antisera. In addition to the expected nuclear localization,we found that OGT was highly concentrated in mitochondria. Since the mitochondrial OGT (103 kDa) was smaller than OGT found in other compartments(116 kDa) we reasoned that it was one of two predicted splice variants of OGT. The N-termini of these isoforms are unique; the shorter form contains a potential mitochondrial targeting sequence. We found that when epitope-tagged,the shorter form (mOGT; 103 kDa) concentrated in HeLa cell mitochondria,whereas the longer form (ncOGT; 116 kDa) localized to the nucleus and cytoplasm. The N-terminus of mOGT was essential for proper targeting. Although mOGT appears to be an active transferase, O-linked GlcNAc-modified substrates do not accumulate in mitochondria. Using immunoelectron microscopy and mitochondrial fractionation, we found that mOGT was tightly associated with the mitochondrial inner membrane. The differential localization of mitochondrial and nucleocytoplasmic isoforms of OGT suggests that they perform unique intracellular functions.
Protection against hypoxia-induced increase in blood-brain barrier permeability: role of tight junction proteins and NFκB
Authors: Brown Rachel C. , Mark Karen S. , Egleton Richard D. , Huber Jason D. , Burroughs Amanda R. , Davis Thomas P.
Published: January 2003

Co-culture with glial cells and glia-conditioned media can induce blood-brain barrier properties in microvessel endothelial cells and protect against hypoxia-induced blood-brain barrier breakdown. We examined the effect of two types of glia-conditioned media on brain microvessel endothelial cell permeability and tight junction protein expression, and studied potential mechanisms of action. We found that C6-glioma-conditioned media, but not rat astrocyte-conditioned media, protected against an increase in permeability induced by exposure to 1% oxygen for 24 hours. This hypoxic stress caused an increase in the expression of tight junction proteins claudin-1 and actin,particularly in cells treated with C6-conditioned media. We found that C6-conditioned media has a significantly higher level of both basic fibroblast growth factor and vascular endothelial growth factor. Treatment with C6-conditioned media for 1 or 3 days protects against hypoxia-induced permeability increases, and this protective effect may be mediated by signal transduction pathways terminating at the transcription factor NFκB.
Krh1p and Krh2p act downstream of the Gpa2p Gα subunit to negatively regulate haploid invasive growth
Authors: Batlle Montserrat , Lu Ailan , Green David A. , Xue Yong , Hirsch Jeanne P.
Published: January 2003

The yeast Gα subunit Gpa2p and its coupled receptor Gpr1p function in a signaling pathway that is required for the transition to pseudohyphal and invasive growth. A two-hybrid screen using a constitutively active allele of GPA2 identified the KRH1 gene as encoding a potential binding partner of Gpa2p. Strains containing deletions of KRH1 and its homolog KRH2 were hyper-invasive and displayed a high level of expression of FLO11, a gene involved in pseudohyphal and invasive growth. Therefore, KRH1 and KRH2 encode negative regulators of the invasive growth pathway. Cells containing krh1Δ krh2Δ mutations also displayed increased sensitivity to heat shock and decreased sporulation efficiency, indicating that Krh1p and Krh2p regulate multiple processes controlled by the cAMP/PKA pathway. The krh1Δ krh2Δ mutations suppressed the effect of a gpa2Δ mutation on FLO11 expression and eliminated the effect of a constitutively active GPA2 allele on induction of FLO11 and heat shock sensitivity, suggesting that Krh1p and Krh2p act downstream of Gpa2p. The Sch9p kinase was not required for the signal generated by deletion of KRH1 and KRH2; however, the cAMP-dependent kinase Tpk2p was required for generation of this signal. These results support a model in which activation of Gpa2p relieves the inhibition exerted by Krh1p and Krh2p on components of the cAMP/PKA signaling pathway.
A role for glycogen synthase kinase-3 in mitotic spindle dynamics and chromosome alignment
Authors: Wakefield James G. , Stephens David J. , Tavaré Jeremy M.
Published: January 2003

Glycogen synthase kinase-3 (GSK-3) is a conserved, multifunctional kinase that is constitutively active in resting cells, and inactivated through phosphorylation by protein kinase B (PKB). We have investigated the temporal and spatial control of GSK-3 phosphorylation during the cell cycle in mammalian cells. We show that GSK-3 is present along the length of spindle microtubules and that a fraction of GSK-3 is phosphorylated during mitosis. Phospho-GSK-3 is abundant at the centrosomes and spindle poles but absent from other areas of the spindle. GSK-3 phosphorylation occurs concomitantly with the appearance of phosphorylated and active PKB at the centrosome, which suggests that PKB is the kinase responsible for phosphorylating and inactivating GSK-3 at the centrosome during mitosis.

We demonstrate that lithium and two structurally distinct inhibitors of GSK-3 promote defects in microtubule length and chromosomal alignment during prometaphase. Treated cells contain mono-oriented chromosomes concentrated at the plus ends of astral microtubules, which are longer than in untreated cells. Live microscopy of cells expressing Histone-2B-GFP confirms that the inhibition of GSK-3 suppresses mitotic chromosome movement and leads to a prometaphase-like arrest. We propose that GSK-3 is regulated in a temporal and spatial manner during mitosis and, through controlling microtubule dynamics,plays an important role in chromosomal alignment on the metaphase plate.
Microtubule involvement in NIH 3T3 Golgi and MTOC polarity establishment
Authors: Magdalena Juana , Millard Thomas H. , Machesky Laura M.
Published: January 2003

Scratch-wound assays are commonly used to study the ability of cells to polarize and migrate. In a previous study we showed that Golgi reorientation in response to a scratch wound is actin-dependent in NIH 3T3 cells but not in astrocytes.

In this investigation, to study cell polarity and motility further, we used the polarization of the Golgi and microtubule organizing center (MTOC), as well as the ability of NIH 3T3 cells to migrate, in a scratch-wound assay. Unlike Golgi polarization, MTOC polarization was not dependent on actin, the Arp2/3 complex or Wiskott-Aldrich syndrome protein (WASP)-family proteins. By contrast, disruption of microtubules inhibited MTOC polarity, but not Golgi polarity. Migration was found to be dependent both on actin and microtubules. Expression of the formin-homology 2 (FH2) region of mDia1 inhibited Golgi polarization and migration but not MTOC polarization. Similarly, ST638, a Src inhibitor, inhibited Golgi polarization and migration but not MTOC polarization, whereas expression of the actin regulator IRSp53 only inhibited cell migration. Interestingly, the inhibition of cell migration by the mDia1 FH2 domain could be overcome by addition of Y27632, an inhibitor of ROCK(Rho-associated kinase). In fact, in the presence of ROCK inhibitor, cell migration was accelerated but polarization of both the Golgi and MTOC were inhibited. These data show that, in NIH 3T3 cells, different aspects of cell polarization and migration occur by different mechanisms, and both actin and microtubule networks are required. In addition, this study indicates that MTOC and Golgi polarization events are separately controlled.
Hardware-in-the-loop simulation of regenerative braking for a hybrid electric vehicle
Authors: Yeo H , Kim H
Published: January 2003

A regenerative braking algorithm and a hydraulic module are proposed for a parallel hybrid electric vehicle (HEV) equipped with a continuous variable transmission (CVT). The regenerative algorithm is developed by considering the battery state of charge, vehicle velocity and motor capacity. The hydraulic module consists of a reducing valve and a power unit to supply the front wheel brake pressure according to the control algorithm. In addition, a stroke simulator is designed to provide a similar pedal operation feeling. In order to evaluate the performance of the regenerative braking algorithm and the hydraulic module, a hardware-in-the-loop simulation (HILS) is performed. In the HILS system, the brake system consists of four wheel brakes and the hydraulic module. Dynamic characteristics of the HEV are simulated using an HEV simulator. In the HEV simulator, each element of the HEV powertrain such as internal combustion engine, motor, battery and CVT is modelled using MATLAB SIMULINK. In the HILS, a driver operates the brake pedal with his or her foot while the vehicle speed is displayed on the monitor in real time. It is found from the HILS that the regenerative braking algorithm and the hydraulic module suggested in this paper provide a satisfactory braking performance in tracking the driving schedule and maintaining the battery state of charge.
Fatigue damage analysis in an automobile stabilizer bar
Authors: Palma E S , Santos E S dos
Published: January 2003

An analysis of fatigue damage in a stabilizer bar in the front suspension (McPherson) of a passenger car was performed. A cumulative fatigue damage theory (linear damage rule) together with experimental and analytical techniques of stress analysis are used to determine the fatigue damage imposed on the stabilizer bar, under both laboratory and actual conditions. Finite element models of the stabilizer bars were used to determine the local stresses at critical regions. These stresses were then measured in the laboratory, by using strain gauges bonded on the material. The assessments of fatigue damage of the stabilizer bar under actual conditions were performed with a component mounted on a vehicle, which was driven over different road surfaces and at different velocities. The results of both experiment types are correlated and discussed.
Sliding mode control for anti-lock brake system of passenger vehicles featuring electrorheological valves
Authors: Choi S-B , Bang J-H , Cho M-S , Lee Y-S
Published: January 2003

This paper presents a sliding mode control for a new anti-lock brake system (ABS) of a passenger vehicle using electrorheological (ER) valves. The Bingham model of an ER fluid is empirically obtained as a function of electric fields, and it is incorporated with the dynamic model of ER valves. The design parameters of the ER valves such as electrode gap are appropriately determined by considering braking forces required for a small-sized passenger vehicle. An electrically controllable ABS using the ER valves is then proposed and its governing equations of motion are derived. Subsequently, sliding mode controllers are formulated for wheel slip control as well as yaw rate control. In the formulation of the sliding mode controllers, the friction force which is difficult to measure in real time is estimated via a sliding mode observer associated with the fuzzy algorithm. Computer simulations for braking performance and steering stability under various road conditions are undertaken in order to demonstrate the effectiveness of the proposed ABS.
Effect of stair descent loading on ultra-high molecular weight polyethylene wear in a force-controlled knee simulator
Authors: Benson L C , DesJardins J D , Harman M K , LaBerge M
Published: January 2003

A loading protocol approximating forces, torques and motions at the knee during stair descent was developed from previously published data for input into a force-controlled knee simulator. A set of total knee replacements (TKRs) was subjected to standard walking cycles and stair descent cycles at a ratio of 70:1 for 5 million cycles. Another set of implants with similar articular geometry and the same ultra-high molecular weight polyethylene (UHMWPE) resin (GUR 415), sterilization and packaging was tested with standard walking cycles only. Implant kinematics, gravimetric wear and surface roughness of the UHMWPE inserts were analysed for both sets of implants. Contact stresses were calculated for both loading protocols using a Hertzian line contact model. Significantly greater weight loss ( p < 0.05) and more severe surface damage of UHMWPE inserts resulted with the walking + stair descent loading protocol compared to walking cycles only. Anterior-posterior (AP) tibiofemoral contact point displacements were lower during stair descent than walking, but not significantly different (p = 0.05). Contact stresses were significantly higher during stair descent than walking, owing to higher axial loads and the smaller radius of curvature of the femoral components at higher flexion angles. High contact stresses on UHMWPE components are likely to accelerate the fatigue of the material, resulting in more severe wear, similar to what is observed in retrieved implants. Thus the inclusion of loading protocols for activities of daily living in addition to walking is warranted for more realistic in vitro testing of TKRs.
Homogeneous charge compression ignition engine-out emission-does flame propagation occur in homogeneous charge compression ignition?
Authors: Kaiser E. W. , Yang J , Culp T , Xu N , Maricq M. M.
Published: January 2003

Engine-out emissions data [CO, CO2, speciated hydrocarbons (HC), and particulate matter (size and number density)] were obtained from a single-cylinder, 660 cm3, homogeneous charge compression ignition (HCCI) engine operated on gasoline fuel using direct in-cylinder injection. Data were taken as functions of the air-fuel ratio (A/F) (30–270), r/min, inlet air temperature and fuel injection timing. Three important observations were made

A sharp break occurs in the CO and CO2 emissions indices beginning near A/F = 75. Above A/F ∼ 100, CO is the primary carbon oxide while for A/F < 70, CO2 is the major carbon oxide. The HC emissions index increases linearly, beginning near A/F ∼ 30:1. Below this A/F, the HC index is characteristic of crevice emissions (∼ 3.5 per cent). These results do not prove this unequivocally, but can be explained by a mechanism in which, for A/F < 75, flame propagation occurs over relatively short distances between the multiple autoignition sites within the combustion chamber. Adiabatic compression calculations indicate that for A/F < 75, the compression temperature (∼ 1150 K) is sufficiently high to support flame propagation. The linear increase in HC emissions above that expected from crevice storage can be explained by noting that autoignition becomes more difficult as the A/F becomes leaner and fewer ignition sites are likely to exist within the combustion chamber, reducing the amount of fuel combusted. Conventional models of HCCI combustion involving multi-zone autoignition may also explain the data, but the above concept is an alternative combustion mechanism for HCCI, which should be considered. Particulate emissions at moderate load from this HCCI engine, while much lower than from a diesel, are similar to those from early-injection DISI (direct injection spark ignition) engines and should not be assumed to be negligible.
Mechanism of smokeless diesel combustion with oxygenated fuels based on the dependence of the equivalence ration and temperature on soot particle formation
Authors: Kitamura T , Ito T , Senda J , Fujimoto H
Published: January 2003

The equivalence ratio φ and temperature T are well known to have a significant effect on the quality of particulate formation, such as the soot volume fraction, particle diameter and number density. The purpose of this work is to clarify the φ-T dependence of soot formation for various kinds of fuels, including paraffinic hydrocarbon, aromatic hydrocarbon and oxygenated hydrocarbon, and to discuss a possibility for smokeless diesel combustion considering particulate size and number density. The sooting φ-T map, showing the tendency to generate soot particles as a function of φ-T and T, was made using a detailed soot kinetic model. The computational results show that oxygenated fuel reactions lead to a lower soot yield, smaller particle diameter, lower number density and narrower sooting φ-T region than those of aliphatic and aromatic fuels, due to the notable reduction in production of both acetylene and polycyclic aromatic hydrocarbons (PAHs). Furthermore, this lower sooting tendency is emphasized as the fuel oxygen content increases. It was also found that the leaner mixture side of the soot formation peninsula on the φ-T map, rather than the lower temperature side, should be utilized to suppress the formation of PAHs and ultra-fine particles together with a large reduction in particulate mass.
Highly α-Stereoselective One-pot Sequential Glycosylation Using Glucosyl Thioformimidate Derivatives
Authors: Chiba Hiroyuki , Mukaiyama Teruaki
Published: January 2003

Several trisaccharides were prepared by efficient highly α-stereoselective one-pot sequential glycosylation using glucosyl p-trifluoromethylbenzylthio-p-trifluoromethylphenyl formimidates (abbreviated to: glucosyl thioformimidates) in the presence of a catalytic amount of TfOH. Factors that controlled the high α-stereoselectivity were determined by characteristic properties of thioformimidate groups contained both in glucosyl donor and acceptor.
Layer-by-Layer Assembly on Hydrogel Surfaces and Control of Human Whole Blood Coagulation
Authors: Sakaguchi Hirokazu , Serizawa Takeshi , Akashi Mitsuru
Published: January 2003

Poly(vinyl alcohol) hydrogels were coated with thin polymer films based on layer-by-layer assembly of dextran sulfate and chitosan. Fabrication of thin multilayer films on the hydrogels was verified in several methods. Anti- versus pro-coagulation of human whole blood was observed on the hydrogels with the outermost surfaces of dextran sulfate and chitosan, respectively.
Determination of Enzyme Immobilized into Electropolymerized Polymer Films
Authors: Thanachasai Saipin , Furukawa Hiroyasu , Yoshida Shoichiro , Watanabe Tadashi
Published: January 2003

A simple, rapid and effective way was devised to determine an enzyme incorporated into electropolymerized conductive polymer films, by combining a thin-layer electropolymerization cell and the Bradford Coomassie colorimetric protein assay. The method has been successfully applied to the determination of horseradish peroxidase (HRP) entrapped into pyrrole and 3-alkylsulfonate pyrrole copolymer films.
Photocleavage Processes in an Iminosulfonate Derivative Usable as Photoacid in Resist Technology
Authors: Lalevée Jacques , Allonas Xavier , Fouassier Jean-Pierre , Shirai Masamitsu , Tsunooka Masahiro
Published: January 2003

The cleavage process of an iminosulfonate was studied through time resolved laser spectroscopy. The S0-S1 and S0-T1 transitions were located on the oxime moiety. Under excitation, the cleavage process occured through a singlet mechanism. Under sensitized excitation, an efficient cleavage of the N–O bond occured in the triplet state of the iminosulfonate. The photoreactivity of this compound was compared to that of parent photobase generators (the O-acyloximes) based on the same oxime chromophore.
Value Change in Oil and Gas Production: III a Time to Buy, a Time to Sell, a Time to Decide
Authors: Lerche I. , Noeth S.
Published: January 2003

Deciding whether to buy new information to potentially improve the residual reserves of a producing oilfield, and what price to pay for the information, which may or may not actually improve the reserves picture, is a problem of some concern to field development and production economics. Here we show how the worth of obtaining new information depends not only on the reserves produced to date but also on the residual reserves still to be produced, on the probability that purchase of new information will indeed improve the known reserves, on the value estimated to be produced by the acquisition, and on the cost of the acquisition. There are also dependencies on production and lifting costs but these are not considered in detail here. The timing of a decision whether to acquire new data and how much to pay for it, are illustrated using total profitable gains made to date as a proxy for time. Two simple examples are worked through in detail so that one can see when the uncertainty of possible gains from newly acquired information are sufficient, relative to costs and the worth of residual reserves still to be produced, to allow management to make an informed and rational decision on whether to acquire and when to acquire new information in respect of the life of the field without such acquisition.
Environmental Concerns: Catastrophic Events and Insurance
Authors: Lempp Christof , Lerche Ian , Paleologos Evan
Published: January 2003

Two conditions can occur in exploration problems that require that a corporation consider some form of insurance. First is the possibility of a catastrophic event occurring during exploration, for instance spilling oil, thereby involving massive and expensive clean-up costs. A corporation would surely like to take out insurance against this possibility. Second is the possibility that the regulatory agencies may consider a unilateral change in the environmental stringency conditions after the project is under way. In this case the corporation could be involved in further costs, thereby lowering potential profitability of a pre-existing contract. The corporation would surely like to option against the possibility of such an event occurring prior to the chance that the contract terms could be changed. These two forms of insurance are not equivalent. In the catastrophic loss event situation one would like to pay an insurance premium to cover the unknown catastrophic costs should they occur. In the regulatory stringency conditions situation, one usually knows ahead of time precisely how such more stringent conditions, if enacted, would influence the corporate profitability and one would like to have a contingency option operating that would be activated if and only if the regulatory agency does indeed enact the new more stringent regulations.
Electricity from Biomass and Hydroelectric Development Projects in Turkey
Authors: Demirbas Ayhan
Published: January 2003

The aim of biomass development projects is to identify whether it is possible to utilize biomass in the energy production sector, by substituting a portion of conventional fuel by biomass, to perform combined combustion. Electricity production from biomass has been found to be a promising method in the nearest future. Turkey's annual biomass potential is 117 million tons or 32 Mtoe. The future of biomass electricity generation lies in biomass integrated gasification/gas turbine technology, which offers high-energy conversion efficiencies. The major research and developments of the biomass power industry are focusing on gasifier scale-up, system analysis and site-specific commercial feasibility studies. Turkey has a total gross hydropower potential of 433 GW, but only 125 GW of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 36% of the economically usable potential of the country would be tapped.
Greenhouse Gas Emissions Due to Power Consumption of Household Whitegoods Appliances
Authors: Stewart Caleb , Hessami Mir-Akbar
Published: January 2003

This paper presents information related to greenhouse gas emissions due to the power consumption of the following household appliances: refrigerators, clothes washers, clothes dryers, freezers, and dishwashers; a possible extension to this analysis would include heaters and air-conditioners. Actual energy consumption data for the period 1993 to 1999 were used to estimate the total carbon dioxide emissions for 1994 to 2009 incremented at 5 years; these data can also be used to estimate the energy consumption of these appliances for 2008–2012 with reference to 1990 for reasons of comparison under the Kyoto Protocol. The total carbon dioxide equivalent emissions for the above household appliances show a peak of 29.6 mega-tonnes CO2 around 1999 with a decreasing trend post 1999 to 27.4 mega-tonnes CO2 in 2009. Details of the analysis for selected appliances show that refrigerators account for over half of total emissions, decreasing from 60.1% in 1994 to 51.6% in 2009. The aggregate trend activity was found to highly depend on the trend activity for emissions for refrigerators. The trend activity for freezers, clothes dryers and clothes washers is increasing for consecutive years from 1994 to 2009 defying the trend exhibited by refrigerators and dishwashers. The reason for this discrepancy is the relatively higher decreases in kWh/annum for refrigerators and dishwashers in contrast to other appliances. The energy consumption curves for each appliance take this differential into account. The energy consumption curve for refrigerators predicts a much faster decrease in kWh/annum than for other appliances thus causing the downward trend post 1999.
Design Criteria for Compressed Air Storage in Hard Rock
Authors: Zimmels Y. , Kirzhner F. , Krasovitski B.
Published: January 2003

Compressed Air Energy Storage (CAES) in underground caverns can be used to generate electrical power during peak demand periods. The excess power generation capacity, which is available when demand is low, is used to store energy in the form of compressed air. This energy is then retrieved during peak demand periods. The structural features and leakage stabilities of the air storage site determines the efficiencies of energy conversions and corresponding economics. The objectives of this paper is to formulate advanced criteria for design of CAES systems in hard rock in Israel, and to examine specific designs performance through predictions available from numerical models. Underground space provides opportunities for safe storage and conservation of energy. This concerns enhanced protection and security as well as lower response to external thermal and mechanical influences (impact and vibrations) that characterize highly controlled environments. Design examples of CAES system are presented and their geomechanical and thermal responses to compression and air release cycles are considered. Comparison is made between different configurations of CAES systems with respect to their expected technical and economical performance. Finally, a new CAES system, that incorporates a vortex tube for enhanced thermal efficiency, is described.
Burying Carbon under the Sea: An Initial Exploration of Public Opinions
Authors: Gough Clair , Taylor Ian , Shackley Simon
Published: January 2003

Geological and ocean sequestration of carbon dioxide is a potential climate change mitigation option that is currently receiving an increasing level of attention within business, academic and policy communities. This paper presents a preliminary investigation of possible public reaction to the technologies under consideration. Using a focus group approach, we consider the similarities between carbon storage technologies and analogous technologies that have generated strong reactions with the public. Initial results suggest that, in principle, carbon capture and storage may be seen as an acceptable approach as a bridging policy while other options are developed. However, concerns were raised regarding the safety of storage and trust in the ability of the various institutions to oversee the process in the long term. This analysis forms part of an on-going study which will continue to investigate the perceptions of a range of stakeholders.
After the ribosome structures: How does peptidyl transferase work?
Authors: MOORE PETER B. , STEITZ THOMAS A.
Published: January 2003

Atomic resolution crystal structures of the large subunit published since the middle of August 2000 prove that the peptidyl transferase center of the ribosome, which is the site of peptide-bond formation, is composed entirely of RNA; the ribosome is a ribozyme. They also demonstrate that alignment of the CCA ends of ribosome-bound peptidyl tRNA and aminoacyl tRNA in the peptidyl transferase center contributes signficantly to its catalytic power. Several issues remain unresolved. For example, do any components of the site enhance the rate of peptide-bond formation chemically? Do intact ribosomes make peptide bonds the same way as the isolated large subunits that have been the source of all this atomic resolution structural information?
Selection of RRE RNA binding peptides using a kanamycin antitermination assay
Authors: PELED-ZEHAVI HADAS , HORIYA SATORU , DAS CHANDREYEE , HARADA KAZUO , FRANKEL ALAN D.
Published: January 2003

The arginine-rich domains of several RNA-binding proteins have been shown to bind their cognate RNAs with high affinities and specificities as isolated peptides, adopting different conformations within different complexes. The sequence simplicity and structural diversity of the arginine-rich motif has made it a good framework for constructing combinatorial libraries and identifying novel RNA-binding peptides, including those targeted to the HIV Rev response element (RRE). Here we describe a modified transcription antitermination reporter assay engineered with kanamycin resistance that enables larger in vivo screens (∼109sequences) than previously possible. We show that the assay detects only specific RNA–protein complexes, and that binders are enriched at least 300-fold per round of selection. We screened a large peptide library in which amino acids with charged, polar, and small side chains were randomly distributed within a polyarginine framework and identified a set of high affinity RRE-binding peptides. Most contain glutamine at one particular peptide position, and the best peptides display significantly higher antitermination activities than Rev or other previously described high-affinity RRE-binding peptides. The kanamycin antitermination (KAN) assay should be useful for screening relatively large libraries and thereby facilitate identification of novel RNA binders.
Rapid determination of rice seed vigour by spontaneous chemiluminescence and singlet oxygen generation during early imbibition
Authors: Chen Wenli , Xing Da , Wang Juan , He Yonghong
Published: January 2003

Using a highly sensitive single photon counter, a spontaneous chemiluminescence (CL) study on rice (Oryza sativa L.) seeds stored in different years was carried out. We first observed that the degree of ageing in rice seeds was related to the intensity of spontaneous CL during early imbibition (0–30 min). Rice seeds stored for a shorter time had a stronger intensity of CL in early imbibition. The germination rate of rice seeds showed an obvious positive correlation with the intensity of spontaneous CL. Singlet oxygen (1O2) in rice seeds during early imbibition was investigated by a CL method using a cypridina luciferin analogue, 2‐methyl‐6‐(p‐methoxyphenyl)‐3,7‐dihydroimidazo [1,2α] pyrazin‐3‐one (MCLA), as a selective CL probe. Additional experimental evidence for the formation of 1O2 came from the quenching effect of sodium azide (NaN3) on MCLA‐mediated rice seeds' CL. Analysis based on the experimental results demonstrated that spontaneous CL in rice seeds during early imbibition was mainly contributed by singlet oxygen (1O2). Copyright © 2002 John Wiley & Sons, Ltd.
Analysis of several fluorescent detector molecules for protein microarray use
Authors: Wiese Rick
Published: January 2003

The utility of several streptavidin‐linked fluorescent detector molecules was evaluated on two protein microarray platforms. Tested detector molecules included: Alexa Fluor 546; R‐phycoerythrin (RPE), orange fluospheres; Cy3‐containing liposomes (Large Unilamellar Vesicles, LUV) labelled with Cy3; and an RPE–antibody complex. The two array architectures tested consisted of an array of murine Fc–biotin and an array of murine IgG (the murine IgG array was probed with a biotinylated rabbit anti‐murine IgG). These platforms allowed for the direct comparison of detector utility by detector recognition of array‐bound biotin. All of the fluorescent detectors examined demonstrated utility on each of the array platforms. For the Fc–biotin array, detector signal intensity (background adjusted) was as follows: RPE–antibody complex > fluospheres > RPE > liposomes > Alexa 546: for the IgG array: RPE/antibody complex > RPE > fluospheres > Alexa546 > liposomes. The RPE–antibody complex fluoresced 67% and 150% more intensely than the next closest detector molecule for the Fc–biotin and the murine IgG arrays, respectively. A marked increase in background fluorescence (as compared to RPE alone) did not accompany the increase in signal intensity gained through RPE–antibody complex use (a true increase in signal:noise ratio). These results suggest that the RPE–antibody complex is superior to other molecules for fluorescent detection of analytes on protein microarrays. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of phenol using an enhanced chemiluminescent assay
Authors: Ilyina A. D. , Martínez Hernández J. L. , Mauricio Benavides J. E. , López Luján B. H. , Bogatcheva E. S. , Romero García J. , Rodríguez Martínez J.
Published: January 2003

Enhanced chemiluminescence (ECL) describes the phenomenon of increased light output in the luminol oxidation reaction catalysed by horseradish peroxidase (HRP) in the presence of certain compounds, such as para‐iodophenol. In this work, the effects of phenol on the para‐iodophenol‐enhanced HRP‐catalysed chemiluninescent reaction intensity in an aqueous buffer (Tris–HCl buffer, pH 8.5) and in a surfactant–water–octane mixture were compared. Preincubation of HRP at low phenol concentrations stimulated the chemiluminescent intensity in the assay performed in an aqueous buffer, but did not have significant effect in the sodium bis(2‐ethylhexyl)sulphosuccinate) (Aerosol OT, AOT) applied system. It was also observed that HRP preincubation with phenol concentration higher than 0.003 mg/mL produced an inhibitory effect on the enzyme activity for both assay systems. Only an inhibitory effect of phenol on the chemiluminescent intensity in the surfactant system in octane (as organic solvent) was observed. Three assays were developed to determine phenol concentration in water and in an organic solvent mixture. The detection limits were 0.006, 0.003 and 0.0005 mg/mL, respectively, for the buffer‐containing system, the AOT‐applied system with phenol standard solutions in water and for the AOT‐applied system with phenol standard solutions in octane. Copyright © 2002 John Wiley & Sons, Ltd.
Studies of visible oscillating chemiluminescence with a luminol–H2O2–KSCN–CuSO4–NaOH system in batch reactor
Authors: Samadi‐Maybodi Abdolraouf , Ourad S. M.
Published: January 2003

Oscillating chemical reactions are complex systems involving a large number of chemical species. In oscillating chemical reactions some species, usually reaction intermediates, exhibit fluctuation in concentration. Visible oscillating chemiluminescence, produced by the addition of luminol (3‐aminophthalhydrazide) to the oscillating system H2O2–KSCN–CuSO4–NaOH, was investigated. In this study the effect of varying the concentration of H2O2, KSCN, CuSO4, NaOH and luminol was investigated in a batch reactor. We showed that the concentration of all components involved in the oscillating chemilumenscent reaction influenced the light intensity and the oscillation period. Copyright © 2002 John Wiley & Sons, Ltd.
Chemiluminescence of lucigenin by electrogenerated superoxide ions in aqueous solutions
Authors: Okajima Takeyoshi , Ohsaka Takeo
Published: January 2003

The chemiluminescence reaction of lucigenin (Luc2+ċ2NO3−, N,N′‐dimethyl‐9,9′‐biacridinium dinitrate) at gold electrodes in dioxygen‐saturated alkaline aqueous solutions (pH 10) was investigated in detail by the use of electrochemical emission spectroscopy. We noted that both O2 and Luc2+ are reduced on a gold electrode in aqueous solution of pH 10 in almost the same potential region. From this fact, we expected chemiluminescence based on a radical–radical coupling reaction of superoxide ion (O2·−) and one‐electron reduced form of Luc2+ (Luc·+, a radical cation). Chemiluminescence was actually observed in the potential range where O2 and Luc2+ were simultaneously reduced at the electrodes. The effects were examined upon addition of enzymes, i.e. superoxide dismutase (SOD) and catalase, into the solution and the substitution of heavy water (D2O) for light water (H2O) as a solvent on the chemiluminescence. In the presence of native and active SOD, chemiluminescence was completely absent. On the other hand, chemiluminescence was observed, unchanged in the presence of either denatured and inert SOD or catalase. In addition, the amount of chemiluminescence in D2O solution was about three times greater than that in H2O solution. These results, together with cyclic voltammetric results, suggest that O2·− participates directly in the chemiluminescence but H2O2 does not, and the chemiluminescence results from the coupling reaction between O2·− and Luc·+ under the present experimental conditions. These chemically unstable species, O2·− and Luc·+, are produced during the simultaneous electroreduction of O2 and Luc2+. The coupling reaction between those radical species would lead to the formation of a dioxetane‐type intermediate and, finally, to chemiluminescence. The chemiluminescence reaction mechanism is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Linear polarized near‐infrared irradiation stimulates mechanical expansion of the rat sagittal suture
Authors: Sasaki Akiko , Touma Yuiko , Ishino Yoshihiro , Tanaka Eiji , Aoyama Junko , Hanaoka Kohichi , Watanabe Mineo , Tanne Kazuo
Published: January 2003

Mechanical sutural separation has been carried out in clinical orthodontics for controlling the growth of the craniofacial skeleton. This study was designed to evaluate the effects of linear polarized near‐infrared ray irradiation on the sutural expansion of rat sagittal suture. Twenty 8‐week‐old Wistar strain male rats were equally divided into experimental and control groups. Suture expansion was carried out for 5 days for all animals using an expansion appliance. The experimental animals were subjected to linear polarized near‐infrared irradiation. This study has demonstrated that linear polarized near‐infrared irradiation stimulates sutural expansion without any pathological changes. Copyright © 2002 John Wiley & Sons, Ltd.
On the optimal mix of corporate hedging instruments: Linear versus nonlinear derivatives
Authors: Gay Gerald D. , Nam Jouahn , Turac Marian
Published: January 2003

We examine how corporations should choose their optimal mix of linear and nonlinear derivatives. We present a
model in which a firm facing both quantity (output) and price (market) risk maximizes its
expected profits when subjected to financial distress costs. The optimal hedging position generally is comprised
of linear contracts, but as the levels of quantity and price‐risk increase, the use of linear contracts
will decline due to the risks associated with overhedging. At the same time, a substitution effect occurs toward
the use of nonlinear contracts. The degree of substitution will depend on the correlation between output levels
and prices. Our model also allows us to provide insight into the relation between a firm's derivatives
usage and its transaction‐cost structure. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark
23:217–239, 2003
Futures hedging using dynamic models of the variance/covariance structure
Authors: Poomimars Ponladesh , Cadle John , Theobald Michael
Published: January 2003

Dynamic futures‐hedging ratios are estimated across seven markets using generalized models of the
variance/covariance structure. The hedging performances of the resultant dynamic strategies are then compared
with static and naïve strategies, both in‐ and out‐of‐sample. Bayesian‐adjusted
hedge ratios also are employed as error purgers. The empirical results indicate that the
generalized dynamic models are well specified and that their use in determining optimal hedge ratios can lead to
improvements in hedging performance as measured by the volatilities of the returns on the optimally hedged
position. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:241–260, 2003
Geoarchaeology and geochronology of pluvial Lake Chapala, Baja California, Mexico
Authors: Davis Loren G.
Published: January 2003

Stratigraphic exposures in natural profiles, archaeological excavation units, backhoe trenches, and an uncased water well from the Laguna Seca Chapala basin in the Central Desert of Baja California (29°N, 115°W) record lake level and climate changes and provide a context for prehistoric occupation predating 9070 yr B.P. and extending through the Holocene. Lithofacies analysis points to the presence of a large (ca. 66 km2) lake prior to 9070 yr B.P., which desiccated by 7.45 ka yr B.P., promoting rapid dune growth. New dating and redefinition of stratigraphic units in the basin refutes earlier models of lacustrine history and prehistoric occupation including a proposed series of Pleistocene lake levels with associated cultural occupations. The geologic record from the Laguna Seca Chapala basin compares well with other paleoenvironmental records in southwestern North America, supporting interpretations of wet and cool conditions in Baja California during the late Pleistocene and early Holocene. © 2003 Wiley Periodicals, Inc.
Archaeomagnetic investigation of two mediaeval brick constructions in north Belgium and the magnetic anisotropy of bricks
Authors: Hus Jozef , Ech‐Chakrouni Souad , Jordanova Diana , Geeraerts Raoul
Published: January 2003

Archaeomagnetic dates derived from geomagnetic field direction records in baked materials are proposed for a mediaeval brick kiln (from inclination I and declination D) and for bricks from a brick wall (from I only) in northern Belgium. They are used to verify whether a brick chronology based on the format of bricks is feasible in Flanders. The brick kiln yielded a highly reliable average magnetization direction corresponding to an archaeomagnetic date around A.D. 1650, using the British and French geomagnetic field secular variation curves as a reference, at least half a century younger than expected from historical data. The fidelity of the geomagnetic records was controlled by measuring the magnetic anisotropy of the bricks. Anisotropy of magnetic susceptibility (AMS) measurements demonstrate that the bricks have a shape related magnetic fabric, which is induced during the molding process. A test to control whether AMS can substitute for the anisotropy of thermo‐remanent magnetization (ATRM) failed because of induced changes during laboratory heating. © 2003 Wiley Periodicals, Inc.