bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular crowding reduces to a similar extent the diffusion of small solutes and macromolecules: measurement by fluorescence correlation spectroscopy
Authors: Dauty Emmanuel , Verkman A. S.
Published: August 2004

Aqueous environments in living cells are crowded, with up to >50 wt% small and macromolecule‐size solutes. We investigated quantitatively one important consequence of molecular crowding—reduced diffusion of biologically important solutes. Fluorescence correlation spectroscopy (FCS) was used to measure the diffusion of a series of fluorescent small solutes and macromolecules. In water, diffusion coefficients (D) were (in cm2/s × 10−8): rhodamine green (270), albumin (52), dextrans (75, 10 kDa; 10, 500 kDa), double‐stranded DNAs (96, 20 bp; 10, 1 kb; 3.4, 4.5 kb) and polystyrene nanospheres (5.4, 20 nm diameter; 2.3, 100 nm). Aqueous‐phase diffusion (Dw) in solutions crowded with Ficoll‐70 (0–60 wt%) was reduced by up to 650‐fold in an exponential manner: Dw = D exp (‐[C]/[C]exp), where [C]exp is the concentration (in wt%) of crowding agent reducing D by 63%. FCS data for all solutes and Ficoll‐70 concentrations fitted well to a model of single‐component, simple (non‐anomalous) diffusion. Interestingly [C]exp were nearly identical (11±2 wt%, SD) for diffusion of the very different types of macromolecules in Ficoll‐70 solutions. However, [C]exp was dependent on the nature of the crowding agent: for example, [C]exp for diffusion of rhodamine green was 30 wt% for glycerol and 16 wt% for 500 kDa dextran. Our results indicate that molecular crowding can greatly reduce aqueous‐phase diffusion of biologically important macromolecules, and demonstrate a previously unrecognized insensitivity of crowding effects on the size and characteristics of the diffusing species. Copyright © 2004 John Wiley & Sons, Ltd.
Sprout inhibition of potatoes with soft‐electron (low‐energy electron beams)
Authors: Todoriki Setsuko , Hayashi Toru
Published: August 2004

The surfaces of potatoes were irradiated with electrons of different energy levels, and the effects on sprouting were investigated. Electrons at 270 keV or higher effectively inhibited sprouting of four cultivars of potatoes, cvs Danshaku, Hokkaikogane, Toyoshiro and May Queen, even after storage at 23 °C for 4 months. Sugar contents in tubers treated with 270‐keV electrons were lower after storage for 3 months than their levels before electron treatment. The levels of glucose, fructose and sucrose were significantly lower in the tubers treated with 270‐keV electrons than in low temperature (5 °C)‐stored tubers. The results indicate the potential of low energy electron treatment for the shelf‐life extension of potatoes as an alternative to treatments with gamma‐rays or chemicals. Copyright © 2004 Society of Chemical Industry
Quality characteristics of a non‐fermented dry‐cured sausage formulated with lemon albedo
Authors: Aleson‐Carbonell Luis , Fernández‐López Juana , Sendra Esther , Sayas‐Barberá Estrella , Pérez‐Alvarez Jose A
Published: August 2004

Dry‐cured sausages were treated with two types of dehydrated lemon albedo (raw and cooked) at five concentrations (0–100 g kg−1 in 25 g kg−1 increments). Several physical and chemical analyses were made during the drying stage, and compositional, textural and sensory analyses were conducted on the finished products. The addition of albedo improved the nutritional properties as a result of fibre addition and may have beneficial effects due to the presence of active biocompounds as evidenced by a decrease in residual nitrite levels and delayed oxidation (based on TBARS values). The sensory properties of samples that resembled the control sausages were those that contained up to 50 g kg−1 dehydrated raw albedo and 75 g kg−1 dehydrated cooked albedo. Copyright © 2004 Society of Chemical Industry
Back Cover: Macromol. Biosci. 9/2004
Authors: Lim Hyun‐A. , Raku Takao , Tokiwa Yutaka
Published: August 2004

Back Cover: The cover illustrates the finding that mammalian enzymes, including α‐chymotrypsin, elastase and trypsin occurring in pancreas, and subtilisin, as microbial enzyme, are able to degrade poly(L‐lactide) (PLA). The PLA is biocompatible and useful to human body. Environmental applications and biomedical materials made of PLA, such as sutures, bone fracture fixation devices and drug delivery microcapsules are degraded by these enzymes.

Further details can be found in the Full Paper by H.‐A. Lim, T. Raku, and Y. Tokiwa* on page 875.
Analytic preconditioners for the electric field integral equation
Authors: Antoine X. , Bendali A. , Darbas M.
Published: August 2004

Since the advent of the fast multipole method, large‐scale electromagnetic scattering problems based on the electric field integral equation (EFIE) formulation are generally solved by a Krylov iterative solver. A well‐known fact is that the dense complex non‐hermitian linear system associated to the EFIE becomes ill‐conditioned especially in the high‐frequency regime. As a consequence, this slows down the convergence rate of Krylov subspace iterative solvers. In this work, a new analytic preconditioner based on the combination of a finite element method with a local absorbing boundary condition is proposed to improve the convergence of the iterative solver for an open boundary. Some numerical tests precise the behaviour of the new preconditioner. Moreover, comparisons are performed with the analytic preconditioner based on the Calderòn's relations for integral equations for several kinds of scatterers. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of macrocyclic aliphatic disulfide oligomers from dithiols by oxidative coupling with oxygen using a copper‐amine catalyst
Authors: Meng Y. Z. , Hllil A. R. , Hay A. S.
Published: August 2004

A new effective method is provided for the synthesis of macrocyclic aliphatic disulfide oligomers by catalytic oxidation of aliphatic dithiols with oxygen in the presence of a copper‐amine catalyst. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of saccharidic polymer colloids via free radical mini‐emulsion polymerization
Authors: Al‐Bagoury M. , Yaacoub E.‐J.
Published: August 2004

Polymer colloids based on 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG) and butyl acrylate (BA) were prepared via free radical mini‐emulsion polymerization. The kinetic and colloidal features of the copolymerization were investigated. The final particle size (D) of the sugar latexes is inversely proportional to the concentration of the anionic emulsifier (sodium dodecyl sulphate, SDS) and the non‐ionic one (alkyl polyglucoside, APG). It was also found that D is independent of the concentration of either the water‐soluble initiator (potassium persulfate, KPS), or the oil‐soluble initiator (2,2′‐azobisisobutyronitrile, AIBN). The rate of mini‐emulsion polymerization is lower in comparison with the conventional emulsion polymerization under the same conditions. The polymerization rate (Rp) and the total number of particles (Np) are proportional to the 0.72th and 0.93th power of the SDS, and to the 1.40th and 2.22th of the APG concentration. Following reaction orders, 0.79/0.06 were obtained for Rp/Np versus the concentration of KPS, and 0.22/−0.01 for AIBN, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Dendritic polyisophthalate endcapped with naphthyl groups for holographic recording
Authors: Kou Huiguang , Shi Wenfang , Lougnot Daniel J. , Lu Yonghua , Ming Hai
Published: August 2004

A novel dendritic polyisophthalate with 12 naphthyl groups at the chain ends was synthesized from 5‐hydroxyisophthalic acid as an AB2 monomer, 1,3,5‐benzenetricarbonyl trichloride as an ‘initiator core’ molecule, and β‐naphthol as an endcapping reagent, via a stepwise growth process. An average molecular weight of 2860 g mol−1, and a refractive index of 1.618 at 650 nm were obtained by gel permeation chromatography and ellipsometry, respectively. A photopolymerizable recording dry film incorporating this dendrimer as a polymeric binder was used for holographic recording. Diffraction gratings with diffraction efficiency exceeding 80%, together with a modulation index of 10−2 were obtained. Copyright © 2004 John Wiley & Sons, Ltd.
Epoxy resins from rosin acids: synthesis and characterization
Authors: Atta Ayman M. , Mansour R. , Abdou Mahmoud I. , Sayed Ashraf M.
Published: August 2004

A series of multifunctional cycloaliphatic glycidyl ester and ether epoxy resins were synthesized by reaction of condensed rosin acid‐formaldehyde resins with epichlorohydrin. The chemical structure of the produced resins was determined by IR and 1H‐NMR analysis. The molecular weight of the produced resins was determined by gel permeation chromatography (GPC). A series of poly‐ (amide‐imide) hardeners were prepared from condensation of Diels–Alder adducts of rosin acid‐maleic anhydride and acrylic acid with triethylene tetramine and pentaethylene hexamine. These amines were also condensed with Diels–Alder adducts of rosin ketones. The curing exotherms of the produced epoxy resins with poly(amide‐imide) hardeners were investigated. The data of mechanical properties, solvent and chemical resistance indicate the superior adhesion of the cured epoxy resins. Copyright © 2004 John Wiley & Sons, Ltd.
High sensitivity and broad dynamic range infrared multiphoton dissociation for a quadrupole ion trap
Authors: Hashimoto Yuichiro , Hasegawa Hideki , Waki Izumi
Published: August 2004

Dynamic control of bath gas pressure in a quadrupole ion trap (QIT) achieved high sensitivity and broad dynamic range infrared multiphoton dissociation (IRMPD). Conventional IRMPD is not sensitive because the bath gas pressure in the QIT needs to be kept at less than 1 mTorr for an effective dissociation, whereas the pressure should be about 20 mTorr for maximum trapping efficiency during ion accumulation. By switching the bath gas pressure between about 20 mTorr during the ion accumulation period and less than 0.6 mTorr during the IRMPD period, it was possible to achieve both maximum trapping efficiency and effective IRMPD. An optimized method for gas introduction enables the trapping efficiency to remain constant during the accumulation period, which permits a broad dynamic range measurement. Copyright © 2004 John Wiley & Sons, Ltd.
Packet scheduling for the delivery of multicast and broadcast services over S‐UMTS
Authors: Karaliopoulos M. , Henrio P. , Narenthiran K. , Angelou E. , Evans B. G.
Published: August 2004

We investigate the packet‐scheduling function within the access scheme of a unidirectional satellite system providing point‐to‐multipoint services to mobile users. The satellite system may be regarded as an overlay multicast/broadcast layer complementing the point‐to‐point third generation (3G) mobile terrestrial networks. The satellite access scheme features maximum commonalties with the frequency division duplex (FDD) air interface of the terrestrial universal mobile telecommunications system (T‐UMTS), also known as wideband code division multiple access (WCDMA), thus enabling close integration with the terrestrial 3G mobile networks and cost‐efficient handset implementations. We draw our attention on one of the radio resource management entities relevant to this interface: the packet scheduler. The lack of channel‐state information and the point‐to‐multipoint service offering differentiate the packet scheduler in the satellite radio interface from its counterpart in point‐to‐point terrestrial mobile networks. We formulate the scheduler tasks and describe adaptations of two well‐known scheduling disciplines, the multilevel priority queuing and weighted fair queuing schemes, as candidates for the time‐scheduling function. Simulation results confirm the significance of the transport format combination set (TFCS) with respect to both the resource utilization achieved by the scheduler and the performance obtained by the flows at packet‐level. The performance gap of the two schemes regarding the fairness provided to competing flows can be narrowed via appropriate selection of the TFCS, whereas the achieved delay and delay variation scores are ultimately dependent on the packet‐level dynamics of individual flows. Copyright © 2004 John Wiley & Sons, Ltd.
System design, capacity dimensioning and revenue estimation for aeronautical communications via satellite
Authors: Werner Markus , Battaglia Lorenzo , Holzbock Matthias
Published: August 2004

The paper discusses various system aspects of commercial aeronautical broadband satellite communications (AirCom). An integrated global system design approach is presented, and key R&D issues along this path are discussed. Some focus is laid on geographic satellite coverage and constellation alternatives. A capacity dimensioning method for global aeronautical communications is developed, using a global flight database, and numerical results from computer simulations are presented. Finally, we estimate the revenues that airlines can expect from passenger telephone and Internet services offered on North Atlantic flights, under the assumption of an existing wireless cabin infrastructure, supporting wireless Internet and GSM telephony. Copyright © 2004 John Wiley & Sons, Ltd.
Salivary prekallikrein output during the ranger training‐induced stress
Authors: Tagashira Sumito , Yamaguchi Keiji , Matsunaga Tsunenori , Toda Kazuo , Hayashi Yoshihiko
Published: August 2004

Saliva can be considered a mirror of the body, reflecting its general conditions. The present study was conducted to identify the changes in specific neurotransmitter and prekallikrein levels in saliva and the correlations between changes in neuroendocrine factors in plasma and saliva after intensive physical training of rangers of Japan Ground Self Defence Force (JGSDF). The subjects were 14 young uniformed males (aged 20–26 years old) who underwent ranger training under the control of the 4th Division of the JGSDF. Before training began and after 30 days of hard training, the levels of prekallikrein, β‐endorphin, serotonin, noradrenaline and dopamine in saliva and plasma were routinely measured. The level of prekallikrein in saliva was significantly increased after training, and the level of β‐endorphin in saliva showed an upward trend after the training. The level of prekallikrein in plasma showed a significant decrease after the training, while the level of β‐endorphin was unchanged. Average concentrations of values in serotonin, noradrenaline and dopamine in plasma were significantly increased after the training. These findings suggest that the comparison of levels of prekallikrein and β‐endorphin in saliva and plasma may give useful insights for the estimation of stress‐induced analgesia. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis, Magnetism, and Crystal Structure of Li2Fe[(PO4)(HPO4)] and its Hydrogen Position Refinement
Authors: Mi Jin‐Xiao , Borrmann Horst , Zhang Hui , Huang Ya‐Xi , Schnelle Walter , Zhao Jing‐Tai , Kniep Rüdiger
Published: August 2004

Lithium iron(III) monophosphate‐monohydrogen‐monophosphate, Li2Fe[(PO4)(HPO4)], was synthesized under mild hydrothermal conditions and its crystal structure was determined by single crystal X‐ray diffraction methods. Crystallographic data: monoclinic, P121/n1 (no. 14), a = 4.8142(2) Å, b = 7.9898(4) Å, c = 7.4868(4) Å, β = 104.398(3)°, V = 278.93(2) Å3, Z = 2, Dx = 3.104 g · cm‐3. The structure is characterized by FeO6 octahedra sharing common O‐corners with six neighbouring PO4 tetrahedra to form a three‐dimensional framework. Lithium cations are located within channels running along [100]. The channels are formed by eight‐membered rings resulting from the connection of alternating FeO6 octahedra (4×) and phosphate tetrahedra (4×). High‐resolution diffraction data allowed to refine a split model for the position of the hydrogen atom. Magnetization data confirm the valence state 3+ for iron and detect an antiferromagnetic ordering of the iron moments below 23.6 K. Thermal decomposition of the compound was investigated by DTA/TG methods.
Synthesis, Structure, and Lanthanide Derivatives of an Unusual Hexameric Alcohol: [2,4,6‐(CF3)3C6H2CH2OH]6
Authors: Edelmann Frank T. , Poremba Peter , Bohnen Frank Michael , Herbst‐Irmer Regine
Published: August 2004

Hitherto unknown 2,4,6‐tris(trifluoromethyl)benzyl alcohol (3) was synthesized in 41 % yield by treatment of freshly prepared RFLi (2) with paraformaldehyde (RF = 2,4,6‐tris(trifluoromethyl)phenyl). According to an X‐ray diffraction study the crystal structure of 3 consists of S6 symmetric cyclic hexamers [2,4,6‐(CF3)3C6H2CH2OH]6. Deprotonation of 3 with NaN(SiMe3)2 in toluene afforded the unsolvated sodium alkoxide derivative RFCH2ONa (4). Homoleptic lanthanide alkoxides of the type Ln(OCH2RF)3 (Ln = Nd (5), Sm (6), Yb (7)) were made by treatment of Ln(C5H5)3 with three equivalents of 3. Similar reactions in a 1:1 molar ratio afforded the bis(cyclopentadienyl)lanthanide alkoxide derivatives (C5H5)2Ln(OCH2RF) (Ln = Nd (8), Sm (9), Yb (10)).
Second‐Sphere Coordination of the Tris(5, 5′‐diamino‐2, 2′‐bipyridine)iron Complex With Arene‐Carboxylate Ligands Through N‐H···O Hydrogen Bonding
Authors: Yang Xiao‐Juan , Wu Biao , Janiak Christoph , Sun Wen‐Hua , Hu Huai‐Ming
Published: August 2004

The tris(5, 5′‐diamino‐2, 2′‐bipyridine)iron(II) complex [Fe(DABP)3]2+ can be engaged in hydrogen‐bonding interactions from the amino groups to carboxylate‐containing molecules as H‐bond acceptors. This so‐called second‐sphere coordination of the metal complex is investigated here by using benzene‐1, 4‐dicarboxylate (terephthalate, L1), benzene‐1, 3‐dicarboxylate (isophthalate, L2), biphenyl‐2, 2′‐dicarboxylate (L3), and benzene‐1, 3, 5‐tricarboxylate (trimesate, L4) anions for N‐H···O bonding. The second‐sphere coordination of [Fe(DABP)3]2+ is further complemented by water molecules of crystallization in the isolated and structurally elucidated compounds of [Fe(DABP)3](L1)·5H2O, [Fe(DABP)3](L2)·8H2O, [Fe(DABP)3](L3)·12.5H2O, and [Fe(DABP)3]3(L4)2·20H2O. The hydrogen‐bonding between [Fe(DABP)3]2+ and the dicarboxylate anions (L1‐L3) decreases from a three‐dimensional supramolecular network (with L1) to discrete units (with L2 and L3) with the increasing number of crystal water molecules. The tricarboxylate ligand L4 is capable of capping the triangular face formed by the three amino groups in [Fe(DABP)3]2+. The solid‐state structures of DABP·2H2O and 5, 5′‐bis(ethoxycarbonylamino)‐2, 2′‐bipyridine (BEBP) are reported.
Synthesis and Structure of a Neodymium Complex with the Nitrilotriacetate Ligand: [NdIII(nta)]n
Authors: Zhang Quan‐Zheng , Lu Can‐Zhong , Yang Wen‐Bin
Published: August 2004

A neodymium complex, [Nd(nta)]n (1) (H3nta = nitrilotriacetic acid) was synthesized and characterized by X‐ray diffraction analysis. Compound 1 exhibits a three‐dimensional network, in which the NdIII ion is coordinated by one nitrogen atom and seven carboxyl oxygen atoms with dodecahedral coordination. One striking feature is that in the Nd coordination center there is no water ligand found.
Synthesis and Crystal Structures of Tris‐[3, 5‐bis(trifluoromethyl)phenyl]arsine Oxide at 293 and 100 K and the Localization of the Trifluoromethyl Groups
Authors: Dietzel Pascal D. C. , Jansen Martin
Published: August 2004

Tris[3, 5‐bis(trifluoromethyl)phenyl]arsine oxide (1) was synthesised by oxidation of tris[3, 5‐bis(trifluoromethyl)phenyl]arsine with hydrogen peroxide in acetone. At 293 K, it crystallizes in the trigonal space group R3c (a = 20.2947(12) Å, c = 11.2484(13) Å, Z = 6, R1 = 0.0254). The compound undergoes a phase transition upon cooling, and it crystallizes in the monoclinic space group Cc at 100 K (a = 13.8621(13) Å, b = 18.6537(17) Å, c = 11.2874(10) Å, Z = 4, R1 = 0.0444). The crystal structures of both phases were determined. The fluorine atoms of the trifluoromethyl groups are strongly disordered at room temperature, which probably indicates a rotational motion in the plane of the fluorine atoms. This motion slows down while lowering the temperature, and the fluorine atoms are localized at 100 K. This point is illustrated by comparison of the experimental electron densities at the CF3 groups. The packing pattern in both structures consists of parallel columns of ecliptically stacked molecules. The columns are hexagonally arranged.
The First Hexa‐coordinated Tetranuclear Nickel Complex {[Ni(en)2]4[H4L]}(ClO4)4·7H2O with Tetrakis‐bidentate Oxamato Bridge
Authors: Liang Mao , Zhu Li‐Na , Liu Shi‐Xiong , Liao Dai‐Zheng , Jiang Zong‐Hui , Yan Shi‐Ping , Cheng Peng
Published: August 2004

The first tetranuclear nickel complex with the oxamato ligand, {[Ni(en)2]4[H4L]}(ClO4)4·7H2O (1) (L = N, N′, N″, N‴‐methanetetrayltetrakismethylenetetrakis (oxamato)), has been prepared and determined by single‐crystal X‐ray analysis. 1 crystallizes in the tetragonal space group I41/a, with a = 15.2744(9), c = 31.3748(2) Å and Z = 4. Each nickel (II) ion is in a distorted octahedral donor atom environment, which comprises four nitrogen atoms of two en molecules and two oxygen atoms of oxamato bridge. The shape of the entity looks like a propeller. The temperature‐dependent magnetic susceptibilities were analyzed by the Curie‐Weiss law; the following values were found C = 4.36 cm3 K mol‐1, θ = ‐24.7 K, respectively.
Partial and Gradual Hydrolysis of 2,2′‐Biimidazoline upon Coordination to Metal Ions, yielding New Chelating Ligands ‐ Synthesis, Characterization and X‐ray Structure of two Examples with Cobalt(III) and Copper(II)
Authors: van Albada Gerard A. , Mohamadou Aminou , Manotti Lanfredi Anna Maria , Mutikainen Ilpo , Turpeinen Urho , Ugozzoli Franco , Reedijk Jan
Published: August 2004

The synthesis, a full structural characterization of two transition‐metal compounds obtained by in‐situ hydrolysis and partly hydrolysis of the ligand 2, 2′‐biimidazoline (abbreviated as biz) is reported. When the biz ligand is completely hydrolysed the compound, N, N′‐bis(2‐aminoethyl)oxamide (abbreviated as H2oxen) is obtained, while the partial hydrolysis results in the ligand N‐(2‐aminoethyl)imidazoline‐2‐carboxamide (abbreviated as Hoxim).

The CoIII ion in the mononuclear CoIII compound, [Co(biz)(oxim)(NCS)](ClO4)(C2H5OH)1/6(H2O)1/6 (1), has an octahedral coordination consisting of 6 nitrogen atoms with a distance varying from 1.889(6) to 1.950(5) Å. Two nitrogen atoms originating from a biz molecule, 3 nitrogen atoms are from the oxim ligand and one nitrogen is from the thiocyanate anion.

Each CuII ion in the dinuclear CuII compound, [Cu2(H2oxen)(oxim)2(C2H5OH)2] (ClO4)2 (2), has a slightly distorted square‐pyramidal structure of which the basal plain consists of3 nitrogen atoms of the oxim ligand and one nitrogen atom of the H2oxen ligand, which is used as a “spacer” connecting the second CuII atom, with Cu‐N distances which vary from 1.944(2) to 2.037(2) Å. The apical position is formed by the oxygen atom of a semi‐coordinating ethanol molecule with a Cu‐O distance of 2.446(2) Å. The compounds are characterized by elemental analysis, ligand field, infrared and, for the CuII ion, also by EPR spectroscopy.
Synthesis and Crystal Structure of Na7Cu3O8, Containing a New Type of Oxocuprate(III) Oligoanion
Authors: Sofin Mikhail , Peters Eva‐Maria , Jansen Martin
Published: August 2004

Na7Cu3O8 was prepared through oxidation of a Na3CuO2/NaCuO mixture (2:1) in dried oxygen at 450 °C. Single crystals have been grown by annealing of Na7Cu3O8, in the presence of Na2O2, at 450 °C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X‐ray analysis of the crystal structure ($P {\bar 1}$, Z = 1, a = 5.5891(2), b = 6.0945(2), c = 7.8890(3) Å, α = 110.059(2), β = 108.669(2), γ = 90.237(2)°) a new Cu3O87‐ oxocuprate anion, consisting of three edge sharing CuO4 squares, is the prominent structural feature. These anions are aligned parallel to the space diagonal of the unit cell and can be regarded as infinite chains from which every fourth copper atom has been removed. This new representative of an oxocuprate(III) anion gives support to the expectation that the gap between dimeric and infinite edge sharing units of square planar cuprate anions can be closed, in principle.
[M(μ‐O2C‐C6H4‐CO2)(NH3)2] (M = Cu, Cd; O2C‐C6H4‐CO2 = benzene‐1, 4‐dicarboxylate, terephthalate): 1D Coordination Polymers with Strong Inter‐Chain Hydrogen Bonding
Authors: Paul Barbara , Zimmermann Boris , Fromm Katharina M. , Janiak Christoph
Published: August 2004

Compounds [M(μ‐O2C‐C6H4‐CO2)(NH3)2] crystallize as straight‐ (M = Cu) and kinked‐chain (M = Cd) coordination polymers through the bridging action of the bis‐mono (Cu) and bis‐bidentate (Cd) benzene‐1, 4‐dicarboxylate (terephthalate) ligand. N‐H···O hydrogen bonding connects the chains to a three‐dimensional supramolecular network. Thermogravimetry shows the compounds to be stable up to 255 °C (M = Cu) and 70 °C (M = Cd) where decomposition starts with the loss of one ammin ligand. [Cd(μ‐O2C‐C6H4‐CO2)(NH3)2] exhibits a luminescence with λem, max = 392 nm (λex = 240 nm) on the same order of magnitude as Na2(O2C‐C6H4‐CO2).
Trovacene Chemistry. 10 [1] The [1]‐ and [2]Silatrovacenophanes (η7‐$\overline{C 7H6)V(η5‐C5H4S}$iR2) and (η7‐$\overline{C 7H6)V(η5‐C5H4SiR2S}$iR2 (R = Me, Ph): Synthesis, Structure, and Ring Opening
Authors: Elschenbroich Christoph , Paganelli Francesca , Nowotny Mathias , Neumüller Bernhard , Burghaus Olaf
Published: August 2004

Heteroannular dilithiation of trovacene, (η7‐C7H7)V(η5‐C5H5) (1˙), and subsequent reaction with the respective dichlorosilane yielded the [1]silatrovacenophanes (η7‐$\overline{C 7H6)V(η5‐C5H4S}$iR2) (2˙, R = Ph; 3˙, R = Me) and the [2]silatrovacenophane (η7‐$\overline{C 7H6)V(η5‐C5H4SiMe2S}$iMe2) (4˙). Structural studies by X‐ray diffraction revealed sandwich tilt angles of 17.3° (2˙) and 3.8° (4˙), respectively, and considerable strain in the ring‐link‐ring region. EPR spectroscopy responds to these distortions in that the g‐tensor is tetragonal (gx = gy ≠ gz) for 4˙ but rhombic (gx ≠ gy ≠ gz) for 2˙ and 3˙. With increasing tilt,  increases slightly towards gfs = 2.0023 and a(51V) decreases, the latter response to tilting being more pronounced. These trends are plausible in view of distortion‐induced mixing of the V(3d) SOMO with ligand π orbitals. Whereas cyclic voltammetry of undistorted 4˙ displays reversible oxidation and reduction, the strained sandwich 2˙ shows irreversible behavior, probably caused by cleavage of the interannular bridge. [1]Silatrovacenophanes are thermally more robust than [1]silaferrocenophanes in that 2˙, exposed to 280 °C, fails to show indications of ring‐opening polymerization (ROP).
Dimeric Rhenium(I) Carbonyl Complexes with Thiosemicarbazone Backbone
Authors: Pereiras‐Gabián G. , Vázquez‐López E. M. , Abram U.
Published: August 2004

Dimeric, neutral rhenium(I) complexes of the composition [Re2(CO)6X(LR)] (X = Cl or Br) are formed when [NEt4]2[Re(CO)3Br3] or [Re(CO)3Cl(CH3CN)2] react with 2, 2′‐dipyridylketone thiosemicarbazones (HLR, R = H, Ph). The thiosemicarbazones deprotonate during the reaction and connect two tricarbonylrhenium(I) units as formally pentadentate bridging ligands. This results in an extremely rare coordination mode, in which the two nitrogen atoms of the hydrazone unit bind to each one of the rhenium atoms. The bond lengths inside the thiosemicarbazonato backbone reflect a large degree of delocalization of electron density.
Wheat pathogenesis‐related proteins of class 4 have ribonuclease activity
Authors: Caporale Carlo , Di Berardino Iris , Leonardi Luca , Bertini Laura , Cascone Annunziata , Buonocore Vincenzo , Caruso Carla
Published: August 2004

We have demonstrated that wheatwin1, a wheat pathogenesis‐related protein of class 4 (PR4), has ribonuclease activity. Both native and recombinant proteins hydrolyse RNA from wheat coleoptils and have antifungal activity. Sepharose‐bound wheatwin1 is able to interact with either wheat or Fusarium culmorum RNA. 3D modelling studies showed that, like ribonucleases A and T1, the action mechanism should involve two His residues, an Arg residue and an Asp residue.
Loss of filament‐forming ability of myosin by non‐enzymatic glycosylation and its molecular mechanism
Authors: Katayama Shigeru , Haga Yoshiaki , Saeki Hiroki
Published: August 2004

Carp and scallop myosin and their subfragments (S‐1 and rod) were reacted with glucose to investigate the effect of non‐enzymatic glycosylation on the functionality of myosin. The filament‐forming ability of the myosin rod diminished with the progress of non‐enzymatic glycosylation and myosin became soluble in 0.1 M NaCl. The inhibition of the self‐assembly of myosin molecules occurred chemically as a result of the increase in negative charge repulsion among myosin molecules and, further, physically as a result of the introduction of the glycosyl units into the surface of the rod region.
Murine male germ cell apoptosis induced by busulfan treatment correlates with loss of c‐kit‐expression in a Fas/FasL‐ and p53‐independent manner
Authors: Choi Yun-Jung , Ok Do-Won , Kwon Dueg-Nam , Chung Jong-il , Kim Heung-Cheol , Yeo Sung-Moon , Kim Teoan , Seo Han-Geuk , Kim Jin-Hoi
Published: August 2004

Male germ cell apoptosis has been extensively explored in rodents. In contrast, very little is known about the susceptibility of developing germ cells to apoptosis in response to busulfan treatment. Spontaneous apoptosis of germ cells is rarely observed in the adult mouse testis, but under the experimental conditions described here, busulfan‐treated mice exhibited a marked increase in apoptosis and a decrease in testis weight. TdT‐mediated dUTP‐X nicked end labeling analysis indicates that at one week following busulfan treatment, apoptosis was confined mainly to spermatogonia, with lesser effects on spermatocytes. The percentage of apoptosis‐positive tubules and the apoptotic cell index increased in a time‐dependent manner. An immediate effect was observed in spermatogonia within one week of treatment, and in the following week, secondary effects were observed in spermatocytes. RT‐PCR analysis showed that expression of the spermatogonia‐specific markers c‐kit and Stra 8 was reduced but that Gli I gene expression remained constant, which is indicative of primary apoptosis of differentiating type A spermatogonia. Three and four weeks after busulfan treatment, RAD51 and FasL expression decreased to nearly undetectable levels, indicating that meiotic spematocytes and post‐meiotic cells, respectively, were lost. The period of germ cell depletion did not coincide with increased p53 or Fas/FasL expression in the busulfan‐treated testis, although p110Rb phosphorylation and PCNA expression were inhibited. These data suggest that increased depletion of male germ cells in the busulfan‐treated mouse is mediated by loss of c‐kit/SCF signaling but not by p53‐ or Fas/FasL‐dependent mechanisms. Spermatogonial stem cells may be protected from cell death by modulating cell cycle signaling such that E2F‐dependent protein expression, which is critical for G1 phase progression, is inhibited.
Apigenin suppresses the expression of VEGF, an important factor for angiogenesis, in endothelial cells via degradation of HIF‐1α protein
Authors: Osada Mayuko , Imaoka Susumu , Funae Yoshihiko
Published: August 2004

Apigenin, a plant‐derived flavone, is a potent inhibitor of cell proliferation and angiogenesis, but the mechanisms leading to the pathological anti‐angiogenic effects of apigenin are still unclear. In this study, we found that apigenin inhibited the hypoxia‐induced expression of vascular endothelial growth factor (VEGF) mRNA in human umbilical artery endothelial cells. Apigenin also suppressed the expression of erythropoietin mRNA, which is a typical hypoxia‐inducible gene, via the degradation of hypoxia‐inducible factor 1 (HIF‐1) α. We investigated the effect of apigenin on the interaction of HIF‐1α with heat shock protein 90 (Hsp90), which is reported to be important for the stabilization of HIF‐1α, and found that VEGF expression was inhibited via degradation of HIF‐1α through interference with the function of Hsp90.
Mifepristone versus the Yuzpe regimen (PC4) for emergency contraception
Authors: Ashok P.W. , Hamoda H. , Flett G.M.M. , Templeton A.
Published: August 2004

Objective: To compare side effects, women's acceptance and satisfaction with mifepristone (100 mg) versus the Yuzpe regimen for emergency contraception (EC). Methods: A total of 1000 women requesting EC within 72 h of unprotected intercourse were randomized to receive mifepristone 100 mg or the standard Yuzpe regimen. Outcome measures included patient acceptability and satisfaction. Results: A total of 620 (62%) questionnaires were returned, 64% in the mifepristone group and 60% in the Yuzpe group. Mifepristone was better tolerated than the Yuzpe regimen. The rates of nausea (P<0.0001), abdominal pain (P=0.001), tiredness (P<0.0001), lethargy (P=0.001), hot flushes (P<0.0001) and dizziness (P<0.0001) were all significantly higher in women given the Yuzpe regimen compared to those who received mifepristone. Of these 94% and 80% in the mifepristone and Yuzpe groups, respectively, were satisfied with treatment (P<0.0001). Of women in the mifepristone group, 56% (181/321) had used the Yuzpe regimen of EC in the past and of these, 93.6% (161/172) indicated they would use mifepristone in the future. A total of four women in the Yuzpe group had mifepristone in the past and all four said they would use mifepristone in the future. Conclusion: Mifepristone has high patient acceptability and few side effects compared to the standard Yuzpe regimen for EC.
Surgical Treatment of Major Vascular Malformations Localized to the Flexor Digitorum Superficialis Muscle: Report of 3 Cases
Authors: REID R. R. , ZIMMERMAN N. , DUMANIAN G. A.
Published: August 2004

Three cases of congenital arteriovenous malformations localized to the flexor digitorum superficialis presented to a single surgeon. In all three cases, the tumours were resectable with negligible morbidity to the upper extremity.
Temporal and spatial history of the 1999–2000 Endeavour Segment seismic series, Juan de Fuca Ridge
Authors: Bohnenstiehl DelWayne R. , Dziak Robert P. , Tolstoy Maya , Fox Christopher G. , Fowler Mathew
Published: August 2004

Two large clusters of earthquake activity in June of 1999 and January of 2000 have dominated recent seismicity along the Endeavour Segment of the Juan de Fuca Ridge. The impacts of the June 1999 sequence on the hydrologic system, which include changes in vent temperature and chemistry within the Main Endeavour Vent Field, have been well documented previously. Analysis of seismic and hydroacoustic data indicates that both sequences exhibit a swarm‐like behavior, characterized by the absence of a dominant main shock event. The epicentral locations of events within the two swarms overlap spatially, with centroid positions near 47°49′ and 47°46′N latitude. During the June 1999 swarm, the initial activity spans the along‐axis region where a shallow axial magma chamber reflector was later imaged. The epicenters then migrate ∼12 km to the south at a rate of 0.3 m/s, consistent with lateral dike propagation. A distinct subcluster of events also occurred in the vicinity of Surveyor Volcano on the overlapping portion of the Cobb Segment. Given its distance from the main swarm, this activity may represent a triggered response to dynamic shaking. The January 2000 swarm has a more limited along‐axis extent, relative to the June 1999 swarm, with no indication of lateral migration. Much of this activity is concentrated in a region predicted to have undergone extension due to dike propagation in 1999. Although it contains fewer total events and is of shorter duration, relative to the June 1999 swarm, the January 2000 activity exhibits a higher peak rate of seismicity and greater mean event magnitude. As in situ temperature monitoring was not in place during January 2000 and vent fluids were not sampled until June 2000, the impacts of this swarm on the hydrothermal system are unknown. The southernmost tip of the Endeavour Segment also is found to be a region of repeating swarm activity. Although morphologic evidence indicates the Cobb Segment has been propagating northward recently, this seismic activity suggests that the western limb of the Endeavour‐Cobb overlap zone remains active.
Bifurcation analysis of a model of the budding yeast cell cycle
Authors: Battogtokh Dorjsuren , Tyson John J.
Published: August 2004

We study the bifurcations of a set of nine nonlinear ordinary differential equations that describe regulation of the cyclin-dependent kinase that triggers DNA synthesis and mitosis in the budding yeast, Saccharomyces cerevisiae. We show that Clb2-dependent kinase exhibits bistability (stable steady states of high or low kinase activity). The transition from low to high Clb2-dependent kinase activity is driven by transient activation of Cln2-dependent kinase, and the reverse transition is driven by transient activation of the Clb2 degradation machinery. We show that a four-variable model retains the main features of the nine-variable model. In a three-variable model exhibiting birhythmicity (two stable oscillatory states), we explore possible effects of extrinsic fluctuations on cell cycle progression.
Oscillatory convection in a two-dimensional porous box with asymmetric lateral boundary conditions
Authors: Rees D. Andrew S. , Tyvand Peder A.
Published: August 2004

The onset of convection in a two-dimensional porous cavity is investigated where the cavity is subject to asymmetric boundary conditions at the lateral walls: one vertical wall is thermally conducting and impermeable, while the other is thermally insulating and open. At the open boundary the saturating fluid flows freely in and out from a hydrostatic reservoir in contact with the porous medium. The top and bottom of the box are impermeable and perfectly conducting. It is shown that the mode for onset of convection is oscillatory in time. This corresponds to a disturbance traveling as a wave through the box from the impermeable wall to the open wall. The preferred eigensolution, its oscillation frequency, and critical Rayleigh number are calculated numerically for different aspect ratios of the porous box, and these values are confirmed by means of suitable asymptotic analyses.
An eddy-viscosity subgrid-scale model for turbulent shear flow: Algebraic theory and applications
Authors: Vreman A. W.
Published: August 2004

An eddy-viscosity model is proposed and applied in large-eddy simulation of turbulent shear flows with quite satisfactory results. The model is essentially not more complicated than the Smagorinsky model, but is constructed in such a way that its dissipation is relatively small in transitional and near-wall regions. The model is expressed in first-order derivatives, does not involve explicit filtering, averaging, or clipping procedures, and is rotationally invariant for isotropic filter widths. Because of these highly desirable properties the model seems to be well suited for engineering applications. In order to provide a foundation of the model, an algebraic framework for general three-dimensional flows is introduced. Within this framework several types of flows are proven to have zero energy transfer to subgrid scales. The eddy viscosity is zero in the same cases; the theoretical subgrid dissipation and the eddy viscosity have the same algebraic structure. In addition, the model is based on a fundamental realizability inequality for the theoretical subgrid dissipation. Results are shown for a transitional and turbulent mixing layer at high Reynolds number and a turbulent channel flow. In both cases the present model is found to be more accurate than the Smagorinsky model and as good as the standard dynamic model. Unlike the Smagorinsky model, the present model is able to adequately handle not only turbulent but also transitional flow.
A simplified Fourier method for computing the internal wavefield generated by an oscillating source in a horizontally moving, depth-dependent background
Authors: Broutman Dave , Rottman James W.
Published: August 2004

A method is developed to describe the linear internal wavefield generated by an oscillating source in horizontally moving, depth-dependent background. Ray theory is used to approximate the vertical eigenfunctions. A spatial solution is then obtained by inverse Fourier transform. This is a practical approach with a more convenient range of validity than the method of spatial ray tracing. The solutions for a stationary source and for a vertically oscillating source in a vertically sheared background current are given for illustration.
Partial defoliation treatments to reduce carrot (Daucus carota L.) taproot splitting
Authors: Gracie A. J. , Brown P. H.
Published: August 2004

Carrot taproots with longitudinal tissue fractures (splits) are commonly deemed unsaleable. This study examined the use of partial leaf defoliation treatments to reduce the incidence of taproots that fracture during growth of the crop (growth splitting) and susceptibility to splitting during harvest (harvest splitting). Two leaf-trimming treatments, vertical and vertical plus horizontal leaf trimming, were compared with untreated control plots. The vertical plus horizontal trimming was the most effective treatment at reducing both harvest and growth splitting. Harvest splitting was significantly reduced by partial leaf defoliation the day prior to commercial harvest. The effectiveness of the treatments declined with time from treatment application. Growth splitting occurred mainly in the weeks prior to commercial harvest and the application of partial defoliation treatments during that period significantly reduced their incidence in crops predisposed to the disorder. A positive correlation between taproot splitting susceptibility and growth splitting was also identified, supporting previous assumptions that both harvest and growth splitting were induced by the same underlying mechanism. The leaf trimming treatments did not preclude mechanical harvesting.
Valuing DNA marker tested bulls for commercial beef production
Authors: Wood B. J. , van der Werf J. H. J. , Parnell P. F.
Published: August 2004

This paper quantifies the benefits of using a sire genotyped for a single recessive gene in a commercial beef herd. A modified gene-flow method was used to account for changing allele frequency over time. The benefits to a commercial breeder of using a genotyped sire were highest when initial allele frequency was moderate and when the sire was used in a self-replacing herd that had increased allele frequency over time. An example of the thyroglobulin gene affecting marbling in beef cattle was used. The value to a self-replacing herd of a sire homozygous for the favourable allele of the thyroglobulin gene was shown to be up to $338 more than of an ungenotyped sire, in a population where the initial gene frequency was 0.3 and the genotype accounted for 0.5 standard deviations of phenotypic variation.
Response of phalaris to differing water regimes or grazing treatments as measured by basal bud weight, water-soluble carbohydrates, and plant tillers
Authors: Lodge G. M.
Published: August 2004

Studies of Phalaris aquatica L. were used to collect data for basal bud (all below ground shoot material) weights, their water-soluble carbohydrate (WSC) content, and green vegetative tillers. A glasshouse study of cvv. Australian and Sirosa was conducted on regrowth after 26 days of plants previously exposed to either non-limiting or limiting (simulated Mediterranean environment, and 3- or 6-week drought) watering treatments. The other studies were of Sirosa phalaris pastures that had previously been subjected to continuous or lenient (resting in both spring and autumn each year) grazing by Merino wethers.
In the glasshouse study, weight of basal buds (g/plant) was highest (13.88 g/plant) for Australian plants in the non-limiting water treatment, but not significantly different among watering treatments for Sirosa plants. Basal bud WSC values ranged from 2126 mg/plant (Australian phalaris, non-limiting water) to <200 mg/plant in 6-week drought and Mediterranean watering treatments of both cultivars. Tiller regrowth was higher in Australian non-limiting water treatment compared with all other treatments.
Post-drought field studies (6 weeks tiller regrowth in May–June 1995) showed that plants in continuously grazed treatments had basal bud weights <11 g/plant, basal bud WSC contents <600 mg/plant, and green vegetative tiller weights <2.5 g/plant, compared with values of >11 g/plant, >1300 mg/plant, and >3.6 g/plant, respectively, for treatments rested for 12 weeks in both autumn and spring. At the end of spring 1995, when plants were post stem elongation and anthesis, basal bud WSC (mg/plant) was significantly higher in autumn–spring rest treatments compared with plants that were continuously grazed (mean values for 2 sites of 2889 and 1458 mg/plant, respectively).
From these data, threshold values of basal bud WSC contents of <600 mg/plant after 6 weeks of regrowth in autumn–early winter, or <2000 mg/plant in flowering plants in late spring in continuously grazed pastures >3 years old, were proposed as useful indicators that management intervention may be required to maintain Sirosa phalaris persistence on the North-West Slopes of New South Wales.
Evaluation of beef cattle genotypes and estimation of direct and maternal genetic effects in a tropical environment. 3. Fertility and calf survival traits
Authors: Prayaga K. C.
Published: August 2004

Data from a crossbreeding experiment were analysed to compare various breeds in a tropical environment. Data included male fertility [scrotal circumference at yearling age (YSC) and at 18 months of age (FSC)], female fertility [calving success (CS) and days to calving (DTC)], and calf survival [survival of calf up to 1 week after birth (WKS) and up to weaning (PWS)] traits. Male fertility traits were analysed as traits of the progeny generation, whereas female fertility and calf survival traits were analysed as traits of the dam (parental generation). Tropically adapted British breed bulls and taurine crossbreds (British × Sanga) had higher YSC and FSC than Zebu and its crosses when adjusted for their body weights. Large negative direct and maternal additive effects on scrotal circumference for Zebu relative to the British breed also suggested reduced scrotal circumference and fertility in Zebu and Zebu-derived crosses. Direct dominance effects for YSC and FSC were only significant when an adjustment for body weight was not included in the model, emphasising that the heterosis observed was only due to the increased body weight.
In general, CS was higher in non-lactating cows and maiden heifers than in lactating cows. The advantage to crossbred genotypes was more pronounced in lactating cows. Among lactating purebreds, CS was significantly (P < 0.05) higher in Belmont Adaptaur (Hereford–Shorthorn, HS) than in Belmont Red (AX), Belmont Brahman cross (BX), and Brahman (Bh). Lactating crossbreds with a common dam breed of HS, AX, BX, and Bh had 19, 33, 21, and 14% greater CS than their respective purebreds. Boran-sired crossbred dams had higher CS than Brahman-sired crossbreds, indicating higher fertility levels of Borans. Significant direct dominance effect for CS in lactating taurine–indicine crosses and in non-lactating taurine–taurine crosses signifies the importance of use of appropriate breed crosses in improving female fertility. Significantly negative (desirable) direct dominance effects for DTC in indicine–indicine and taurine–indicine crosses suggest an advantage from crossbreeding in achieving early calvings. High mortalities were recorded in calves born to HS dams from matings with Brahman bulls due to dystocia. This resulted in low WKS and PWS for HS dam breeds. All additive and dominance effects for calf survival traits were non-significant except for the direct dominance effect in taurine–indicine crosses for PWS. Moderate percentage heterosis estimates in lactating cows for CS and desirable, significant, but low percentage heterosis estimates for DTC were observed. Percentage heterosis estimates for calf survival traits were low and non-significant.