bluuebunny/crossref_metadata_2025_split huggingface dataset:
Golgi Vesiculation and Lysosome Dispersion in Cells Lacking Cytoplasmic Dynein
Authors: Harada A. , Takei Y. , Kanai Y. , Tanaka Y. , Nonaka S. , Hirokawa N. 
Published: July 2002

Cytoplasmic dynein, a minus end–directed, microtubule-based motor protein, is thought to drive the movement of membranous organelles and chromosomes. It is a massive complex that consists of multiple polypeptides. Among these polypeptides, the cytoplasmic dynein heavy chain (cDHC) constitutes the major part of this complex. To elucidate the function of cytoplasmic dynein, we have produced mice lacking cDHC by gene targeting. cDHC−/− embryos were indistinguishable from cDHC+/−or cDHC+/+ littermates at the blastocyst stage. However, no cDHC−/− embryos were found at 8.5 d postcoitum. When cDHC−/− blastocysts were cultured in vitro, they showed interesting phenotypes. First, the Golgi complex became highly vesiculated and distributed throughout the cytoplasm. Second, endosomes and lysosomes were not concentrated near the nucleus but were distributed evenly throughout the cytoplasm. Interestingly, the Golgi “fragments” and lysosomes were still found to be attached to microtubules.
These results show that cDHC is essential for the formation and positioning of the Golgi complex. Moreover, cDHC is required for cell proliferation and proper distribution of endosomes and lysosomes. However, molecules other than cDHC might mediate attachment of the Golgi complex and endosomes/lysosomes to microtubules.
Dielectric and optical properties of lead-activated sodium and potassium chloride crystals
Authors: J S Dryden  , G G Harvey  
Published: July 2002

As part of a study of the aggregation of impurity ions in alkali halides, measurements of dielectric loss, of optical absorption and of emission spectra have been made on NaCl: Pb2+and KCl: Pb2+crystals. Changes in the optical absorption and the emission spectra with aggregation of the Pb2+-vacancy pairs are more pronounced in NaCl than in KCl. The main conclusions from the NaCl: Pb2+measurements are:changes in the absorption and emission spectra result from the same aggregation process studied previously in many alkali halide crystals by dielectric measurements;the emission spectra, but not the absorption, change when the divalent ion-vacancy pairs (dipoles) form the initial aggregates (trimers); later in the aggregation process both absorption and emission change;the optical measurements show that the aggregation takes place in several definite stages and the results are not inconsistent with the model proposed earlier, viz. the initial aggregates are trimers and these grow into pentamers, and then heptamers etc. by the addition of dipoles, two at a time.The dielectric absorption measurements give activation energies for the diffusion of Pb2+-vacancy pairs through NaCl and KCl lattices of 0·80 ev and 0·85 ev respectively.
Simple transient and non-linear analysis of high-field domains in GaAs
Authors: R Harrison  
Published: July 2002

An approximate non-linear study of the phenomenological aspects of the Gunn effect in gallium arsenide has been made. We have attempted, with reasonable success, to analyse quantitatively that region of electron dynamics which includes the growing of the electric field domain from some initial electric field perturbation.From the initial transient analysis we derive two asymptotic forms of field instability for the boundary value problem, and from inspection of the behaviour of the dynamic impedance of the specimen we conclude that there are three conditions for the successful nucleation of a high-field domain. For initial instabilities to commence either the resistivity of the specimen must be less than some critical value or the product of carrier concentration and specimen length (n0l) must be greater than some minimum value. For the domain to be stable in the steady state, the non-linear analysis indicates that the product of the carrier concentration and the square of the domain widthd(n0d2) should be greater than some critical minimum.Finally, if the non-linear velocity-field characteristic can be approximated by a parabola for fields greater than the threshold field for negative differential resistivity then we can derive a set of approximate analytical results for the rise time, peak field and width of a domain, and also specify the minimum specimen length required for a domain to be fully formed.
Dislocation damage by spark cutting in cadmium single crystals
Authors: C Luke  , K E Puttick  
Published: July 2002

A method is described for estimating dislocation damage in crystals as a result of spark cutting. The method allows direct comparison of dislocation arrangement in the same area before and after cutting and is applied to estimate the maximum depth of damage (mdd) in cadmium single crystals using a dislocation etch on the (101bar above 0) plane.The investigation suggests that previous work on other metals has underestimated the mdd and in addition shows:The moving-wire cutter commonly used to section metal crystals frequently makes mechanical contact with the workpiece, with resultant shorting and mechanical abrasion.A simple fixed-wire cutter produces a more satisfactory and damage-free cut than the moving wire.Using this fixed wire, the mdd is a function of the diameter of the wire.Using the lowest available spark energy and a wire of 0·001 inch diameter, the maximum depth of damage in cadmium can be reduced to 0·1 mm.
Studies of plasma production at hypervelocity microparticle impact
Authors: D Smith  , N G Adams  
Published: July 2002

This paper is concerned with an investigation of the plasma generated during the impact of hypervelocity microparticles with a metal target. A laboratory source of hypervelocity micron-sized iron particles is first described which utilizes a 2 MV Van de Graaff generator, followed by a discussion of the techniques used to determine the mass and velocity of the particles. On impact of the iron projectiles on a slatted molybdenum target, charge is generated, extracted from the region of impact by suitably biasing a gridded electrode, and subsequently detected using a conventional wideband electronic amplifier or an electron multiplier. It is shown statistically that during impact equal numbers of electrons and positive ions are produced - indicating plasma generation - and that the total charge released (Q) may be described empirically in terms of the mass (m) and velocity (v) of the particle by a simple power law relationship of the kindQαmαvβ, with β = 3·2 ± 0·1 over the complete velocity range investigated (0·05 to 10 km s−1) and with α = 0·85 forv>1 km s−1and 1·33 forv<1 km s−1. It is also shown that the charge extracted from the plasma reaches a maximum a few microseconds after impact and subsequently decays exponentially with a time constant of several micro-seconds.A crude mass analysis of the positive ions generated during the impact using a simple time-of-flight mass spectrometer has indicated that, over the velocity range investigated, the dominant ions in the spectrum are characteristic of the projectile and not the target material. From considerations of the relative abundance of the metal ions in the spectra, together with the known relative metal atom concentrations in the iron projectiles, the temperatures of the plasmas have been estimated (from Saha equilibrium considerations) to be of the order of several thousands of degrees Kelvin.In a detailed discussion, attempts are made to consider how the kinetic energy of the projectile is dissipated - eventually producing plasma - in terms of available theoretical models of hypervelocity impact. It is shown that the most satisfactory model of this very complex interaction appears to be one in which the relative importance of shock-wave propagation into the projectile and target materials is considered. Finally, a discussion of the properties and the temporal behaviour of the impact-produced plasma is presented in order to assess the relative importance of diffusion and recombination processes, thus to assist in the interpretation of the experimental results obtained in this study.
Experimental and theoretical study of a stationary high-current arc in a supersonic nozzle flow
Authors: W Hermann  , U Kogelschatz  , L Niemeyer  , K Ragaller  , E Schade  
Published: July 2002

In a previous paper (Hermannet al1974) a detailed experimental and theoretical investigation of an arc in a supersonic nozzle flow was initiated by discussing the high-pressure arc section near the stagnation point.This paper is a continuation of this work for the section further downstream, especially within the nozzle. Extensive measurements of temperature, flow velocity, pressure and electric field strength are described. Theoretical results are obtained by a two-zone model.A detailed comparison between theory and experiment allows for the first time a complete quantitative discussion of all effects influencing the arc and the flow. Compared with the arc in the high-pressure section the influence of radiative energy transfer decreases. Instead, flow turbulence becomes the dominating exchange mechanism.
Application of the dusty-gas model to the permeability of a porous medium to a dissociating gas in local chemical equilibrium
Authors: P G Wright  
Published: July 2002

The dusty-gas model is employed to obtain expressions for the flow of a dissociating gas (in local chemical equilibrium) through a porous medium, or a capillary tube. The resulting equations can be expressed in a manner that is formally similar to those for the flow of a single nonreacting gas, but with a viscous term involving a dependence of viscosity on pressure, and a diffusive term which involves not only Knudsen diffusion coefficients but also the binary mutual diffusion coefficientD1vfor interdiffusion of dissociated and associated species.For an isomerizing gas, however, these complications virtually disappear. The equilibrium composition, and therefore the viscosity, no longer varies with pressure; and the dependence on the binary mutual diffusion coefficient (to a good approximation) is removed by a cancellation of terms.The effect of flow in an adsorbed layer is considered.
Microwave radiometric investigation of the positive column instability in pulsed nitrogen discharges
Authors: Omesh Sahni  , W C Jennings  
Published: July 2002

A microwave radiometric technique has been used to study the positive column instability in pulsed nitrogen discharges. The technique involves monitoring the effective temperature of microwave radiation as a function of the longitudinal magnetic field. The critical magnetic fieldBcfor the onset of the instability is found to be dependent on both the discharge current and the duration of the excitation pulse. The experimental results are consistent with an explanation based on significant cumulative ionization.The plasma became turbulent at progressively lower values of magnetic field aboveBcas the discharge current was increased. Further increase in current led to the unstable regime beyondBcreverting back to stability on progressively increasing the magnetic field.
A set-theoretic approach to database searching and clustering.
Authors: Krause A , Vingron M 
Published: July 2002

Abstract
MOTIVATION: In this paper, we introduce an iterative method of database searching and apply it to design a database clustering algorithm applicable to an entire protein database. The clustering procedure relies on the quality of the database searching routine and further improves its results based on a set-theoretic analysis of a highly redundant yet efficient to generate cluster system. RESULTS: Overall, we achieve unambiguous assignment of 80% of SWISS-PROT sequences to non-overlapping sequence clusters in an entirely automatic fashion. Our results are compared to an expert-generated clustering for validation. The database searching method is fast and the clustering technique does not require time-consuming all-against-all comparison. This allows for fast clustering of large amounts of sequences. AVAILABILITY: The resulting clustering for the PIR1 (Release 51) and SWISS-PROT (Release 34) databases is available over the Internet from http://www.dkfz-heidelberg.de/tbi/services/modest/b rowsesysters.pl. CONTACT: a.krause@dkfz-heidelberg.de; m.vingron@dkfz-heidelberg.de
Fast assignment of protein structures to sequences using the
Intermediate Sequence Library PDB-ISL
Authors: Teichmann Sarah A. , Chothia Cyrus , Church George M. , Park Jong 
Published: July 2002

Abstract
Motivation: For large-scale structural assignment to sequences, as in computational structural genomics, a fast yet sensitive sequence search procedure is essential. A new approach using intermediate sequences was tested as a shortcut to iterative multiple sequence search methods such as PSI-BLAST.
Results: A library containing potential intermediate sequences for proteins of known structure (PDB-ISL) was constructed. The sequences in the library were collected from a large sequence database using the sequences of the domains of proteins of known structure as the query sequences and the program PSI-BLAST. Sequences of proteins of unknown structure can be matched to distantly related proteins of known structure by using pairwise sequence comparison methods to find homologues in PDB-ISL. Searches of PDB-ISL were calibrated, and the number of correct matches found at a given error rate was the same as that found by PSI-BLAST. The advantage of this library is that it uses pairwise sequence comparison methods, such as FASTA or BLAST2, and can, therefore, be searched easily and, in many cases, much more quickly than an iterative multiple sequence comparison method. The procedure is roughly 20 times faster than PSI-BLAST for small genomes and several hundred times for large genomes.
Availability: Sequences can be submitted to the PDB-ISL servers at http://stash.mrc-lmb.cam.ac.uk/PDB˙ISL/or http://cyrah.ebi.ac.uk:1111/Serv/PDB˙ISL/and can be downloaded from ftp://stash.mrc-lmb.cam.ac.uk/pub/PDB˙ISL/or ftp://ftp.ebi.ac.uk/pub/contrib/jong/PDB˙ISL/
Contact: sat@mrc-lmb.cam.ac.ukand jong@ebi.ac.uk
Taxonomic markup language: applying XML to systematic data
Authors: Gilmour R. 
Published: July 2002

Abstract
Summary: An XML document type definition (DTD) is provided for the description of taxonomic relationships between organisms. Two XSL stylesheets for the graphical presentation of simple taxonomic trees are also provided.
Availability: The DTD and stylesheets along with sample files are available at http://www.albany.edu/~gilmr/pubxml/.
Contact: gilmr@cnsvax.albany.edu
Validating clustering for gene expression data
Authors: Yeung K. Y. , Haynor D. R. , Ruzzo W. L. 
Published: July 2002

Abstract
Motivation: Many clustering algorithms have been proposed for the analysis of gene expression data, but little guidance is available to help choose among them. We provide a systematic framework for assessing the results of clustering algorithms. Clustering algorithms attempt to partition the genes into groups exhibiting similar patterns of variation in expression level. Our methodology is to apply a clustering algorithm to the data from all but one experimental condition. The remaining condition is used to assess the predictive power of the resulting clusters—meaningful clusters should exhibit less variation in the remaining condition than clusters formed by chance.
Results: We successfully applied our methodology to compare six clustering algorithms on four gene expression data sets. We found our quantitative measures of cluster quality to be positively correlated with external standards of cluster quality.
Availability: The software is under development.
Contact: kayee@cs.washington.edu
Supplementary information: http://www.cs.washington.edu/homes/kayee/cluster or http://www.cs.washington.edu/homes/ruzzo/cluster
* To whom correspondence should be addressed.
Low Temperature Direct 2-Propanol Fuel Cells
Authors: Qi Zhigang , Hollett Mark , Attia Alan , Kaufman Arthur 
Published: July 2002

2-Propanol exhibits a substantially higher cell voltage than methanol in a direct liquid fuel cell at a current density less than ca.

100

mA
/

cm

2

.

Although the performance increases with cell temperature, the cell can deliver 690 mV at a current density of

20

mA
/

cm

2

at room temperature. These features could make 2-propanol an attractive fuel for portable power applications. © 2002 The Electrochemical Society. All rights reserved.
Pre‐Programmed Rod‐Shaped Microgels to Create Multi‐Directional Anisogels for 3D Tissue Engineering
Authors: Braunmiller Dominik L. , Babu Susan , Gehlen David B. , Seuß Maximilian , Haraszti Tamás , Falkenstein Andreas , Eigen Julian , De Laporte Laura , Crassous Jérôme J. 
Published: September 2022

AbstractMicron‐scale anisometric microgels have received increasing attention to replace macromolecule solutions to create injectable 3D regenerative hydrogels. Interlinking these rod‐shaped microgels results in microporous constructs, while incorporating magnetic nanoparticles inside the microgels enables their alignment to introduce directionality. This report demonstrates that the angle of microgel alignment in a static external magnetic field can be pre‐programmed, broadening their applicability to artificially assemble into specific architectures. The magnetic rod‐shaped polyethylene glycol microgels are prepared via in mold polymerization. Ellipsoidal maghemite nanoparticles, integrated as responsive fillers are pre‐aligned either parallel or orthogonal to the long axis of the microgel with a weak magnetic field during rod fabrication to implement additional control over their magnetic orientation and allow their precise manipulation and actuation. The magnetic response of the microgels to static and rotating magnetic fields is discussed depending on various process and design parameters, such as magnetic field strength, angular frequency, and pre‐alignment. Finally, the applicability of the approach for tissue engineering is highlighted by growing mouse fibroblasts in three dimensions within Anisogels, i. e., hydrogels containing a mixture of rods with both a parallel and orthogonal orientation, marking a new step toward more advanced functional cell templating for tissue engineering.
Constructing Three‐Phase Heterojunction with 1D/3D Hierarchical Structure as Efficient Trifunctional Electrocatalyst in Alkaline Seawater
Authors: Yu Qingping , Liu Xiaobin , Liu Guishan , Wang Xinping , Li Zhenjiang , Li Bin , Wu Zexing , Wang Lei 
Published: September 2022

AbstractRational design of highly efficient, robust, and low‐cost trifunctional electrocatalysts for oxygen reduction reaction (ORR), hydrazine oxidation reaction (HzOR), and hydrogen evolution reaction (HER) is extremely urgent for seawater‐based renewable energy conversion and storage, including direct hydrazine fuel cells (DHzFC) and overall hydrazine splitting (OHzS). Herein, FeP/FeNi2P encapsulated in N, P co‐doped hierarchical carbon (FeNiP‐NPHC) in situ grown on nickel foam is fabricated via a hydrothermal‐pyrolysis‐phosphidation procedure. Benefiting from the strong coupling effect among FeP, FeNi2P, and N, P co‐doped carbon at the three‐phase heterojunction interface, as well as the unique 1D/3D hierarchical structure, the as‐prepared FeNiP‐NPHC shows superior ORR (E1/2 = 0.83 V), HzOR (E100 = 7 mV), and HER (E100 = ‐180 mV) performance in alkaline seawater. Density functional theory functions indicate that constructing three‐phase heterojunction interface of FeNiP‐NPHC can effectively adjust the d‐band center and electronic structure, which is conductive to balance and optimize the trifunctional electrocatalytic performance. As proof of concept, the self‐assembled DHzFC is utilized to power the OHzS in alkaline seawater successfully, verifying application potential of the FeNiP‐NPHC as trifunctional electrocatalyst.
An Enzyme‐Engineered Nonporous Copper(I) Coordination Polymer Nanoplatform for Cuproptosis‐Based Synergistic Cancer Therapy
Authors: Xu Yuzhi , Liu Si‐Yang , Zeng Leli , Ma Hansu , Zhang Yanfei , Yang Huihui , Liu Yuchen , Fang Shuo , Zhao Jing , Xu Yunsheng , Ashby Charles R. , He Yulong , Dai Zong , Pan Yihang 
Published: September 2022

AbstractCuproptosis, a newly identified form of regulated cell death that is copper‐dependent, offers great opportunities for exploring the use of copper‐based nanomaterials inducing cuproptosis for cancer treatment. Here, a glucose oxidase (GOx)‐engineered nonporous copper(I) 1,2,4‐triazolate ([Cu(tz)]) coordination polymer (CP) nanoplatform, denoted as GOx@[Cu(tz)], for starvation‐augmented cuproptosis and photodynamic synergistic therapy is developed. Importantly, the catalytic activity of GOx is shielded in the nonporous scaffold but can be “turned on” for efficient glucose depletion only upon glutathione (GSH) stimulation in cancer cells, thereby proceeding cancer starvation therapy. The depletion of glucose and GSH sensitizes cancer cells to the GOx@[Cu(tz)]‐mediated cuproptosis, producing aggregation of lipoylated mitochondrial proteins, the target of copper‐induced toxicity. The increased intracellular hydrogen peroxide (H2O2) levels, due to the oxidation of glucose, activates the type I photodynamic therapy (PDT) efficacy of GOx@[Cu(tz)]. The in vivo experimental results indicate that GOx@[Cu(tz)] produces negligible systemic toxicity and inhibits tumor growth by 92.4% in athymic mice bearing 5637 bladder tumors. This is thought to be the first report of a cupreous nanomaterial capable of inducing cuproptosis and cuproptosis‐based synergistic therapy in bladder cancer, which should invigorate studies pursuing rational design of efficacious cancer therapy strategies based on cuproptosis.
Super‐Reversible CuF2 Cathodes Enabled by Cu2+‐Coordinated Alginate
Authors: Xia Jiale , Wang Zeyi , Rodrig Nuwanthi D. , Nan Bo , Zhang Jiaxun , Zhang Weiran , Lucht Brett L. , Yang Chongyin , Wang Chunsheng 
Published: September 2022

AbstractCopper fluoride (CuF2) has the highest energy density among all metal fluoride cathodes owing to its high theoretical potential (3.55 V) and high capacity (528 mAh g−1). However, CuF2 can only survive for less than five cycles, mainly due to serious Cu‐ion dissolution during charge/discharge cycles. Herein, copper dissolution is successfully suppressed by forming Cu2+‐coordinated sodium alginate (Cu‐SA) on the surface of CuF2 particles during the electrode fabrication process, by using water as a slurry solvent and sodium alginate (SA) as a binder. The trace dissolved Cu2+ in water from CuF2 can in situ cross‐link with SA binder forming a conformal Cu‐SA layer on CuF2 surface. After water evaporation during the electrode dry process, the Cu‐SA layer is Li‐ion conductor but Cu2+ insulator, which can effectively suppress the dissolution of Cu‐ions in the organic 4 m LiClO4/ethylene carbonate/propylene carbonate electrolyte, enhancing the reversibility of CuF2. CuF2 electrode with SA binder delivers a reversible capacity of 420.4 mAh g‐1 after 50 cycles at 0.05 C, reaching an energy density of 1009.1 Wh kg‐1. Cu2+ cross‐link polymer coating on CuF2 opens the door for stabilizing the high‐energy and low‐cost CuF2 cathode for next‐generation Li‐ion batteries.