bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pyrene Excimer Fluorescence of Yeast Alcohol Dehydrogenase: A Sensitive Probe to Investigate Ligand Binding and Unfolding Pathway of the Enzyme
Authors: Santra Manas Kumar , Dasgupta Debjani , Panda Dulal 
Published: October 2005

ABSTRACTThe cysteine residues of yeast alcohol dehydrogenase (YADH) were covalently modified by N‐(1‐pyrenyl) maleimide (PM). A maximum of 3.4 cysteines per YADH monomer could be modified by PM. The secondary structure of PM‐YADH was found to be similar to that of the native YADH using far‐UV circular dichroism. The covalent modification of YADH by PM inhibited the enzymatic activity indicating that the active site of the enzyme was altered. PM‐YADH displayed maximum excimer fluorescence at an incorporation ratio of 2.6 mol of PM per monomeric subunit of YADH. Nucleotide adenine dinucleotide (NAD) divalent zinc and ethanol reduced the excimer fluorescence of PM‐YADH indicating that these agents induce conformational changes in the enzyme. Guani‐dinium hydrochloride (GdnHCl)‐induced unfolding of YADH was analyzed using tryptophan fluorescence, pyrene excimer fluorescence and enzymatic activity. The unfolding of YADH was found to occur in a stepwise manner. The loss of enzymatic activity preceded the global unfolding of the protein. Further, changes in tryptophan fluorescence with increasing GdnHCl suggested that YADH was completely unfolded by 2.5 M GdnHCl. Interestingly, residual structures of YADH were detected even in the presence of 5 M GdnHCl using the excimer fluorescence of PM‐YADH.
Microencapsulation
Authors: Thies Curt 
Published: October 2005

AbstractThis article discusses the concept of microencapsulation, many processes by which microcapsules are produced, and a number of microcapsule applications. Nomenclature and selected materials used to form microcapsules are summarized briefly. Encapsulation processes discussed include complex coacervation, polymer–polymer incompatibility, interfacial andin situpolymerization, solvent evaporation, extractive drying, submerged stationary nozzle, centrifugal nozzle, spray drying, fluidized bed, and rotational suspension separation. Microcapsule applications discussed include graphic arts, including carbonless copy paper; prolonged herbicides and insecticides; oral and injectable pharmaceuticals; live cell immobilization for biomedical and biotechnological applications; enhanced performance of food ingredients, such as flavors and vitamins; and several general consumer uses, such as cosmetics and adhesives.
Nitrobenzene and Nitrotoluenes
Authors: Dugal Markus 
Published: October 2005

Abstract

Nitrobenzene is a pale yellow to yellowish brown liquid with a boiling point of 207–212°C, depending on its purity. It is a very toxic substance with a maximum allowable concentration (PEL) of 1 ppm. The commercial production of nitrobenzene involves the direct nitration of benzene using a mixture of nitric and sulfuric acids, with typical yields of 96–99%. The main derivatives of nitrobenzene are
ortho
‐,
meta
‐, and
para
‐nitrochlorobenzene. These are toxic, with a PEL of 0.1 ppm for
p
‐nitrochlorobenzene.

Nitrotoluene exists as three isomers:
o
‐,
m
‐, and
p
‐nitrotoluene. The
o
‐ and
m
‐nitrotoluenes are clear yellow liquids at 25°C, whereas
p
‐nitrotoluene is a crystalline solid (mp 53.5°C). The nitrotoluenes are fairly toxic, with a PEL of 2 ppm.
Nitrides
Authors: Roberts Kenneth L. , Covington Leroy 
Published: October 2005

AbstractNitrides may be classified as being ionic or salt‐like, metallic, nonmetallic (diamond‐like) or volatile. The properties of transition‐metal metallic nitrides and the diamond‐like nonmetallic nitrides are described. Additionally, sulfur and phosphorus form polymeric nitride species. Transition‐metal binary nitrides, made on a small scale, are used for high strength and hardness primarily as refractory coatings. Boron, aluminum, and silicon nitrides find use as refractories, ablative materials, abrasives, and coatings. The combination of high thermal conductivity, high electrical resistivity and linear thermal expansion coefficient makes aluminum nitride a sufficient ceramic material for electronic applications. Several powder‐specific synthesis methods for aluminum nitride are described and the effects of oxygen and impurity contamination are mentioned. Lithium nitride finds application in batteries and catalysts. Gallium and indium nitrides are used in such optoelectronic devices as light‐emitting diodes. The material and electrical properties of gallium nitride (GaN) position it as a prime candidate for high power microwave applications. GaN has shown extensive potential in the microelectronics environment for high electron mobility transistors. The manufacture and processing of nitride coatings by case hardening is presented as well as the processing of the structurally important silicon nitride. A brief summary of the optical and electronic properties, including optical adsorption and field emission, of carbon nitride are also presented. Plasma enhanced and hot filament chemical vapor deposition techniques are highlighted as two of the most current preparation methods used to obtain carbon nitride films.
Nuclear Fuel Reserves
Authors: Bullen Daniel B. 
Published: October 2005

Abstract
The primary fuel for light‐water nuclear reactors is natural or slightly enriched (3–5%) uranium dioxide. Estimates of the world reserves of uranium resources are based on the cost of recovery for various ore types and classified as reasonably assured, estimated, or additional, speculative resources. World reactor‐related requirements are expected to increase from usage through the year 2010. Additional sources of uranium are expected to come from the use of reprocessed plutonium in mixed‐oxide fuels, the deenrichment of weapon‐grade, high enriched uranium with natural uranium, and the fabrication of mixed‐oxide fuels using surplus weapons‐grade plutonium.
Superconductivity and Superconductors
Authors: Glowacki Bartek. A. 
Published: October 2005

Abstract
This article aims to address the issue of superconductivity and superconductors from the point of view of technology and applications, despite the fact that the majority of recent developments relate more to the fundamental aspects of superconductivity. The technology sections focus on the discovery of superconductivity and the phenomena and characteristics that define it. Low temperature superconductors (LTS) are discussed. Niobium and tantalum devices fall into this category. These materials are probably the most important electrode material for tunnel junction fabrication and are used in superconducting devices, eg, the superconducting quantum interference device (SQUID), X‐ray detectors, optical detectors, and mixers. Magnesium dibromide has made us aware of the possibility of the existence of new superconducting materials and this compound is detailed. High temperature ceramic superconductors are discussed and they focus mainly on the evolution of superconductivity by chemical doping of copper and its compounds. An extensive section on application includes details on the following uses: in transmission cables, research electromagnets, electromagnets for nmr and mri systems, current leads, fault current limiters, magnetically guided surgical instruments, and levitating train, to name a few.
A new method for critical points calculation from cubic EOS
Authors: Nichita Dan Vladimir 
Published: October 2005

AbstractDevelopment of accurate and efficient methods for direct calculation of critical points is valuable for phase equilibrium calculations in chemical and petroleum engineering. A new method for critical points calculation is developed. For critical point calculation methods, the spinodal equation is given by setting to zero a determinant of nc (number of components) or nc‐1 order, containing second‐order derivatives of thermodynamic potentials. In this approach, this determinant has a lower order, which does not depend on the number of components in the mixture, but on the number of reduction parameters, with no restrictions on the binary interaction parameters (BIPs). The new method has been tested for several mixtures having various phase diagram shapes, and proved its reliability. The computation effort for each step for correcting temperature and molar volume can be significantly reduced. The proposed method is particularly efficient for mixtures with many components and few nonzero BIPs. Cubic two‐parameter EOS are used; however, the proposed method can be applied for any EOS that observes the restrictions of the Reduction Theorem. © 2005 American Institute of Chemical Engineers AIChE J, 2006
How can a β‐sheet peptide be both a potent antimicrobial and harmfully toxic? Molecular dynamics simulations of protegrin‐1 in micelles
Authors: Langham Allison A. , Khandelia Himanshu , Kaznessis Yiannis N. 
Published: October 2005

AbstractIn this work, the naturally occurring β‐hairpin antimicrobial peptide protegrin‐1 (PG‐1) is studied by molecular dynamics simulation in all‐atom sodium dodecylsulfate and dodecylphosphocholine micelles. These simulations provide a high‐resolution picture of the interactions between the peptide and simple models of bacterial and mammalian membranes. Both micelles show significant disruption, as is expected for a peptide that is both active against bacteria and toxic to host cells. There is, however, clear differentiation between the behavior in SDS versus DPC, which suggests different mechanisms of interaction for PG‐1 with mammalian and bacterial membranes. Specifically, the equilibrium orientation of the peptide relative to SDS is a mirror image of its position relative to DPC. In both systems, the arginine residues of PG‐1 strongly interact with the head groups of the micelles. In DPC, the peptide prefers a location closer to the core of the micelle with Phe12, Val14, and Val16 imbedded in the core and the other side of the hairpin, which includes Leu5 and Tyr7, located closer to the surface of the micelle. In SDS, the peptide prefers a location at the micelle–water interface. The peptide position is reversed, with Leu5 and Cys6 imbedded furthest in the micelle core and Phe12, Val14, and Val16 on the surface of the micelle. We discuss the implications of these results with respect to activity and toxicity. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 219–231, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
[Ru(TAP)3]2+‐Photosensitized DNA Cleavage Studied by Atomic Force Microscopy and Gel Electrophoresis: A Comparative Study
Authors: Uji‐i Hiroshi , Foubert Philippe , De Schryver Frans C. , De Feyter Steven , Gicquel Etienne , Etoc Ariane , Moucheron Cécile , Kirsch‐De Mesmaeker Andrée 
Published: October 2005

AbstractTopological modifications of plasmid DNA adsorbed on a variety of surfaces were investigated by using atomic force microscopy (AFM). On mica modified with 3‐aminopropyltriethoxysilane (APS) or poly‐L‐lysine, the interaction between the plasmid DNA and the surface “freezes” the plasmid DNA conformation deposited from solution, and the AFM images resemble the projection of the three‐dimensional conformation of the plasmid DNA in solution. Modified mica with low concentrations of Mg2+ leads to a decrease in the interaction strength between plasmid DNA and the substrate, and the AFM images reflect the relaxed or equilibrium conformation of the adsorbed plasmid DNA. Under these optimized deposition conditions, topological modifications of plasmid DNA were produced under irradiation in the presence of [Ru(TAP)3]2+ (TAP=1,4,5,8‐tetraazaphenanthrene), which is a non‐intercalating complex, and were followed as a function of illumination time. The observed structural changes correlate well with the conversion of the supercoiled covalently closed circular form (ccc form) into the open circular form (oc form), induced by a single‐strand photocleavage. The AFM results obtained after fine‐tuning of the plasmid DNA–substrate interaction compare well with those observed from gel electrophoresis, indicating that under the appropriate deposition conditions, AFM is a reliable technique to investigate irradiation‐induced topological changes in plasmid DNA.
New Hybrid Bidentate Ligands as Precursors for Smart Catalysts
Authors: Goettmann Frédéric , Boissière Cédric , Grosso David , Mercier François , Le Floch Pascal , Sanchez Clément 
Published: October 2005

Abstract1‐Phosphanorbornadiene derivatives were grafted onto various periodically organized mesoporous powders, including a new zirconia/silica mixed oxide synthesized by aerosol techniques. After complexation with the [Rh(CO)2]+ fragment, these materials were revealed to be more active in olefin hydrogenation than their homogeneous counterparts. The reasons for this higher activity are discussed in the light of theoretical modeling. Various surface treatments, such as esterification, drying, and functionalization with PhSi(OEt)3, provided insights into the nature and mechanism of formation of the active species. Zirconia‐based materials were found to be active in internal olefin hydroformylation. Investigation of the mechanism of this reaction shows that the isomerization step is catalyzed by the Lewis acidic support, whereas the hydroformylation step is driven by the rhodium catalyst. Dissociation of these two steps leads to enhancement of activity.
Host–Guest Interactions in the Supramolecular Incorporation of Fullerenes into Tailored Holes on Porphyrin‐Modified Gold Nanoparticles in Molecular Photovoltaics
Authors: Imahori Hiroshi , Fujimoto Atsushi , Kang Soonchul , Hotta Hiroki , Yoshida Kaname , Umeyama Tomokazu , Matano Yoshihiro , Isoda Seiji , Isosomppi Marja , Tkachenko Nikolai V. , Lemmetyinen Helge 
Published: October 2005

AbstractNovel gold nanoparticles modified with a mixed self‐assembled monolayer of porphyrin alkanethiol and short‐chain alkanethiol were prepared (first step) to examine the size and shape effects of surface holes (host) on porphyrin‐modified gold nanoparticles. The porphyrin‐modified gold nanoparticles with a size of about 10 nm incorporated C60 molecules (guest) into the large, bucket‐shaped holes, leading to the formation of a supramolecular complex of porphyrin–C60 composites (second step). Large composite clusters with a size of 200–400 nm were grown from the supramolecular complex of porphyrin–C60 composites in mixed solvents (third step) and deposited electrophoretically onto nanostructured SnO2 electrodes (fourth step). Differences in the porphyrin:C60 ratio were found to affect the structures and photoelectrochemical properties of the composite clusters in mixed solvents as well as on the SnO2 electrodes. The photoelectrochemical performance of a photoelectrochemical device consisting of SnO2 electrodes modified with the porphyrin–C60 composites was enhanced relative to a reference system with small, wedged‐shaped surface holes on the gold nanoparticle. Time‐resolved transient absorption spectroscopy with fluorescence lifetime measurements suggest the occurrence of ultrafast electron transfer from the porphyrin excited singlet states to C60 or the formation of a partial charge‐transfer state in the composite clusters of supramolecular complexes formed between porphyrin and C60 leading to efficient photocurrent generation in the system. Elucidation of the relationship between host–guest interactions and photoelectrochemical function in the present system will provide valuable information on the design of molecular devices and machines including molecular photovoltaics.
Molecular Beam Rotational Spectrum of Cyclobutanone–Trifluoromethane: Nature of Weak CH⋅⋅⋅OC and CH⋅⋅⋅F Hydrogen Bonds
Authors: Ottaviani Paolo , Caminati Walther , Favero L. B. , Blanco Susana , López Juan C. , Alonso José L. 
Published: October 2005

AbstractThe molecular beam Fourier transform microwave spectrum of cyclobutanone–trifluoromethane has been assigned and measured. The carbon atom of trifluoromethane lies in the plane of the heavy atoms of cyclobutanone. The complex is stabilized by one C‐H⋅⋅⋅OC and two C‐H⋅⋅⋅F‐C weak hydrogen bonds. The C‐H⋅⋅⋅OC interaction, involving one carbonylic oxygen, is studied for the first time in detail with rotationally resolved spectroscopy. The two C‐H⋅⋅⋅F‐C weak hydrogen bonds involve two fluorine atoms of trifluoromethane and two hydrogens of the same methylenic group in the α position.
Multiple Component Approaches to C‐Glycosyl β‐Amino Acids by Complementary One‐Pot Mannich‐Type and Reformatsky‐Type Reactions
Authors: Dondoni Alessandro , Massi Alessandro , Sabbatini Simona 
Published: October 2005

AbstractThe development of new methods for the preparation of C‐glycosyl β‐amino acid libraries with chemical and stereochemical diversity levels was investigated and the results are described herein. Two complementary one‐pot three‐component Mannich‐type and Reformatsky‐type synthetic strategies have been developed for the construction of chiral 3‐amino propanoate fragments (eventually bis‐substituted at C‐2) directly linked to the anomeric carbon of pyranose and furanose residues. Both methods involved as the initial step the coupling of a sugar aldehyde to p‐methoxybenzylamine but differed in the nucleophile (a d2 synthon equivalent) which was successively added: a ketene silyl acetal (Mannich route) or a bromozinc enolate (Reformatsky route). Individual C‐glycosyl β‐amino esters were isolated as single 3R diastereoisomers in fair to excellent yield (60–90 %) and their structure assigned by NMR spectroscopy (Riguera protocol) supported by X‐ray crystallography. A tentative explanation of the observed stereochemical outcome based on transition‐state models is provided. A preliminary study on the synthesis of α,α‐difluoro C‐glycosyl β‐amino acids via a more traditional Reformatsky route is also reported.
Ring‐Opening Polymerization of Lactide with Group 3 Metal Complexes Supported by Dianionic Alkoxy‐Amino‐Bisphenolate Ligands: Combining High Activity, Productivity, and Selectivity
Authors: Amgoune Abderramane , Thomas Christophe M. , Roisnel Thierry , Carpentier Jean‐François 
Published: October 2005

AbstractA series of new alkoxy‐amino‐bis(phenols) (H2L 1–6) has been synthesized by Mannich condensations of substituted phenols, formaldehyde, and amino ethers or diamines. The coordination properties of these dianionic ligands towards yttrium, lanthanum, and neodymium have been studied. The resulting Group 3 metal complexes have been used as initiators for the ring‐opening polymerization of rac‐lactide to provide poly(lactic acid)s (PLAs). The polymerizations are living, as evidenced by the narrow polydispersities of the isolated polymers, together with the linear natures of number average molecular weight versus conversion plots and monomer‐to‐catalyst ratios. Complex [Y(L6){N(SiHMe2)2}(THF)] (17) polymerized rac‐lactide to heterotactic PLA (Pr = 0.90 at 20 °C) and meso‐lactide to syndiotactic PLA (Pr = 0.75 at 20 °C). The in situ formation of [Y(L6)(OiPr)(THF)] (18) from 17 and 2‐propanol resulted in narrower molecular weight distributions (PDI = 1.06). With complex 18, highly heterotactic PLAs with narrow molecular weight distributions were obtained with high activities and productivities at room temperature. The natures of the ligand substituents were shown to have a significant influence on the degree of control of the polymerizations, and in particular on the tacticity of the polymer.
Input–output organization of jaw movement‐related areas in monkey frontal cortex
Authors: Hatanaka Nobuhiko , Tokuno Hironobu , Nambu Atsushi , Inoue Tomio , Takada Masahiko 
Published: October 2005

AbstractThe brain mechanisms underlying mastication are not fully understood. To address this issue, we analyzed the distribution patterns of cortico–striatal and cortico–brainstem axon terminals and the origin of thalamocortical and intracortical fibers by injecting anterograde/retrograde tracers into physiologically and morphologically defined jaw movement‐related cortical areas. Four areas were identified in the macaque monkey: the primary and supplementary orofacial motor areas (MIoro and SMAoro) and the principal and deep parts of the cortical masticatory area (CMaAp and CMaAd), where intracortical microstimulation produced single twitch‐like or rhythmic jaw movements, respectively. Tracer injections into these areas labeled terminals in the ipsilateral putamen in a topographic fashion (MIoro vs. SMAoro and CMaAp vs. CMaAd), in the lateral reticular formation and trigeminal sensory nuclei contralaterally (MIoro and CMaAp) or bilaterally (SMAoro) in a complex manner of segregation vs. overlap, and in the medial parabranchial and Kölliker‐Fuse nuclei contralaterally (CMaAd). The MIoro and CMaAp received thalamic projections from the ventrolateral and ventroposterolateral nuclei, the SMAoro from the ventroanterior and ventrolateral nuclei, and the CMaAd from the ventroposteromedial nucleus. The MIoro, SMAoro, CMaAp, and CMaAd received intracortical projections from the ventral premotor cortex and primary somatosensory cortex, the ventral premotor cortex and rostral cingulate motor area, the ventral premotor cortex and area 7b, and various sensory areas. In addition, the MIoro and CMaAp received projections from the three other jaw movement‐related areas. Our results suggest that the four jaw movement‐related cortical areas may play important roles in the formation of distinctive masticatory patterns. J. Comp. Neurol. 492:401–425, 2005. © 2005 Wiley‐Liss, Inc.
Overlapping intracellular and differential synaptic distributions of dopamine D1 and glutamate N‐methyl‐D‐aspartate receptors in rat nucleus accumbens
Authors: Hara Yuko , Pickel Virginia M. 
Published: October 2005

AbstractThe dopamine D1 receptor (D1R) in the nucleus accumbens (Acb) shell is highly implicated in psychostimulant‐evoked locomotor activity and reward, whereas the D1R in the Acb core is more crucial for appetitive instrumental learning. These behavioral effects depend in part on interactions involving glutamatergic N‐methyl‐D‐aspartate (NMDA) receptors, whose essential NR1 subunit has physical associations with the D1R. To determine the relevant sites for D1R activation and interactions involving NMDA receptors, we examined the electron microscopic immunolabeling of D1R and NR1 C‐terminal peptides in rat Acb shell and core. In each Acb subdivision, the D1Rs were located principally on extrasynaptic plasma membranes of dendritic shafts and spines and more rarely were associated with cytoplasmic endomembranes. Many D1R‐labeled somata and dendrites also contained NR1 immunoreactivity. In comparison with D1R, NR1 immunoreactivity was more often seen in the cytoplasm and near asymmetric synapses on somatodendritic profiles. In these profiles, notable overlapping distributions of D1R and NR1 occurred near endomembranes. The exclusively D1R‐ or D1R‐ and NR1‐containing dendrites were most prevalent in the Acb shell, but were also present in the Acb core. In each region, NR1 was also detected in axon terminals without D1R, which formed excitatory‐type synapses with D1R‐labeled dendrites. These results provide ultrastructural evidence that D1Rs in the Acb have subcellular distributions supporting, 1) intracellular cotrafficking with NR1 and 2) modulation of the postsynaptic excitability in spiny neurons affected by presynaptic NMDA receptor activation. The region‐specific differences in receptor distributions suggest a major, but not exclusive, involvement of Acb D1R in reward‐related processing. J. Comp. Neurol. 492:442–455, 2005. © 2005 Wiley‐Liss, Inc.