bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering and Prosthetic‐Group Modification of Myoglobin: Peroxidase Activity, Chemical Stability and Unfolding Properties
Authors: Roncone Raffaella , Monzani Enrico , Nicolis Stefania , Casella Luigi
Published: May 2004

The role of myoglobin (Mb) is not yet completely understood and recent evidence indicates it is involved in a variety of pseudo‐enzymatic functions. Mb is also extensively used as a tool to redesign novel active‐site features and introduce new activities into a protein. This review summarizes our approach to enhance the peroxidase‐like activity of Mb toward phenolic compounds by combining two different strategies of protein modification, i.e. active‐site engineering and cofactor replacement. The main objective of active‐site engineering is to increase the rate of hydrogen peroxide activation upon reaction at the iron(III) center, while cofactor replacement facilitates substrate interaction at the protein active site, thereby increasing the efficiency of the catalytic process and stereoselective recognition of the substrate. The thermodynamic stability of the modified Mb derivatives has been evaluated through guanidinium chloride induced and thermal unfolding experiments. As expected, both protein mutation and cofactor replacement decrease the stability of the protein, the latter effect being somewhat more pronounced for the Mb derivatives studied here. For evaluating the catalytic efficiency of the protein in non‐natural reactions, the chemical stability of the protein during catalysis is also important and therefore a new protocol was developed to evaluate the competitive degradation undergone by the protein upon substrate oxidation. It was found that autodegradation can occur through two different pathways involving oxidation of protein residues by the Mb active species or by a substrate‐derived phenoxy radical. The peroxidase‐like nitrating activity and the sulfoxidation reactions promoted by Mb, both involving the nitrite ion as a cosubstrate, have also been briefly described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Preparation of Diamidochloro(cyclopentadienyl)titanium Derivatives as Pre‐Catalysts for Olefin Polymerization − X‐ray Molecular Structure of [Ti(η5‐C5H5){1,2‐C6H4(NCH2CH2CH3)2}Cl] and [Ti{η5‐C5H4(SiMe3)}{1,2‐C6H4(NCH2CH2CH3)2}Cl]
Authors: Tabernero Vanessa , Cuenca Tomás , Herdtweck Eberhardt
Published: May 2004

The synthesis of N,N′‐alkyl 1,2‐phenylenediamines 1,2‐C6H4(NHR)2 [R = CH2CH2CH3 (nPr), CH2tBu (Np)] was carried out in three steps by lithiation of the primary 1,2‐phenylenediamine, reaction with the appropriate acyl chloride and reduction with LiAlH4. The addition of nBuLi to a stirred solution of N,N′‐alkyl diamines in cold hexane resulted in the immediate deposition of the corresponding lithium salts, which react with [MCpR′Cl3] to give the diamidochloro(η5‐cyclopentadienyl)titanium and ‐zirconium complexes [MCpR′{1,2‐C6H4(NR)2}Cl] (4−10) [M = Ti, Zr; CpR′ = η5‐C5H5, η5‐C5(CH3)5, η5‐C5H4(SiMe3); R = nPr, Np]. The compound [Ti(η5‐C5H5){1,2‐C6H4(NnPr)2}Cl] (3) was obtained by treatment of [Ti(η5‐C5H5)Cl3] with 1,2‐C6H4(NHnPr)2 in the presence of NEt3 in toluene. All the reported compounds were characterized by the usual analytical and NMR spectroscopic methods. The molecular structures of 3 and 7 were determined by single‐crystal X‐ray crystallography. The compounds described here were further investigated as potential olefin polymerization catalysts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Joint compensation of IQ imbalance, frequency offset and phase noise in OFDM receivers
Authors: Tubbax Jan , Van der Perre Liesbet , Donnay Stéphane , Engels Marc , Moonen Marc , De Man Hugo
Published: May 2004

Zero‐IF receivers are getting a lot of attention because of their potential to enable low‐cost OFDM terminals. However, zero‐IF receivers also introduce IQ imbalance which can have a huge impact on the performance. Rather than increasing component cost to decrease the IQ imbalance, an alternative is to tolerate the IQ imbalance and compensate for it digitally. Current solutions either require additional analog hardware or are based on digital algorithms that converge too slowly for bursty communication. Moreover, the impact of a frequency offset and phase noise on the IQ imbalance estimation/compensation problem is not considered. In this paper, we analyze the joint IQ imbalance/frequency offset/phase noise estimation and propose a low‐cost, highly effective, all‐digital mitigation scheme. For large IQ imbalance large frequency offsets and in the presence of phase noise our solution still results in an average implementation loss below 0.5 dB. It, therefore, enables the design of low‐cost, lowcomplexity OFDM receivers. Copyright © 2004 AEI
Development of a convection–diffusion‐reaction magnetohydrodynamic solver on non‐staggered grids
Authors: Sheu Tony W. H. , Lin R. K.
Published: May 2004

This paper presents a convection–diffusion‐reaction (CDR) model for solving magnetic induction equations and incompressible Navier–Stokes equations. For purposes of increasing the prediction accuracy, the general solution to the one‐dimensional constant‐coefficient CDR equation is employed. For purposes of extending this discrete formulation to two‐dimensional analysis, the alternating direction implicit solution algorithm is applied. Numerical tests that are amenable to analytic solutions were performed in order to validate the proposed scheme. Results show good agreement with the analytic solutions and high rate of convergence. Like many magnetohydrodynamic studies, the Hartmann–Poiseuille problem is considered as a benchmark test to validate the code. Copyright © 2004 John Wiley & Sons, Ltd.
Prediction of unsteady, separated boundary layer over a blunt body for laminar, turbulent, and transitional flow
Authors: Holloway D. Scott , Walters D. Keith , Leylek James H.
Published: May 2004

The focus of this paper is to study the ability of unsteady RANS‐based CFD to predict separation over a blunt body for a wide range of Reynolds numbers particularly the ability to capture laminar‐to‐turbulent transition. A perfect test case to demonstrate this point is the cylinder‐in‐crossflow for which a comparison between experimental results from the open literature and a series of unsteady simulations is made. Reynolds number based on cylinder diameter is varied from 104 to 107 (subcritical through supercritical flow). Two methods are used to account for the turbulence in the simulations: currently available eddy–viscosity models, including standard and realizable forms of the k–ε model; and a newly developed eddy–viscosity model capable of resolving boundary layer transition, which is absolutely necessary for the type and range of flow under consideration. The new model does not require user input or ‘empirical’ fixes to force transition. For the first time in the open literature, three distinct flow regimes and the drag crisis due to the downstream shift of the separation point are predicted using an eddy–viscosity based model with transition effects. Discrepancies between experimental and computational results are discussed, and difficulties for CFD prediction are highlighted. Copyright © 2004 John Wiley & Sons, Ltd.
Flavonoids from the Resin of Dracaena cochinchinensis
Authors: Zheng Qing‐An , Li Hai‐Zhou , Zhang Ying‐Jun , Yang Chong‐Ren
Published: May 2004

Chemical investigation of the red herbal resin of Dracaena cochinchinensis resulted in the isolation of three new configurationally isomeric flavonoids: 6,4′‐dihydroxy‐7‐methoxy‐8‐methylflavane (=3,4‐dihydro‐2‐(4‐hydroxyphenyl)‐7‐methoxy‐8‐methyl‐2H‐[1]benzopyran‐6‐ol; 1), 5,4′‐dihydroxy‐7‐methoxy‐6‐methylflavane (=3,4‐dihydro‐2‐(4‐hydroxyphenyl)‐7‐methoxy‐6‐methyl‐2H‐[1]benzopyran‐5‐ol; 2), and 7,4′‐dihydroxy‐5‐ methoxyhomoisoflavane (=3,4‐dihydro‐3‐[(4‐hydroxyphenyl)methyl]‐5‐methoxy‐2H‐[1]benzopyran‐7‐ol; 3). Their structures were identified by means of detailed spectral analysis. In addition, thirteen known compounds were isolated from D. cochinchinensis: 7‐hydroxy‐4′‐methoxyflavane (4), 2,4,6‐trimethoxy‐4′‐hydroxydihydrochalcone (5), 2,4‐dimethoxy‐4′‐hydroxydihydrochalcone (6), 7,8‐(methylenedioxy)‐4′‐hydroxyhomoisoflavane (7), 4′,7‐dihydroxy‐8‐methylflavane (8), 2,6‐dimethoxy‐4,4′‐dihydroxydihydrochalcone (9), 2‐methoxy‐4,4′‐dihydroxydihydrochalcone (10), 7‐methoxy‐6,4′‐dihydroxyhomoisoflavane (11), 2‐methoxy‐4,4′‐dihydroxychalcone (12), 4′,7‐dihydroxyflavane (13), 7,4′‐dihydroxyhomoisoflavane (14), 7,4′‐dihydroxyhomoisoflavone (15), and 7,4′‐dihydroxyflavone (16). Compounds 7, 8, 9, 14, and 15 have been isolated for the first time from this type of herbal source.
Chemical Constituents from the Fruits of Madhuca latifolia
Authors: Siddiqui Bina S. , Khan Shazia , Kardar M. Nadeem , Aslam Huma
Published: May 2004

From the fruit coats of the medicinal plant Madhuca latifolia were isolated three new compounds, the triterpenoid madhucic acid (=3β‐(octanoyloxy)‐11‐oxoolean‐12‐en‐28‐oic acid; 1), the untypical isoflavone madhushazone (=9‐methoxy‐7‐(2,3,6‐trimethoxyphenyl)‐[1,3]dioxolo[4,5‐g][1]benzopyran‐8(8H)‐one; 2), and a bis(isoflavone) named madhusalmone (=5,14‐dimethoxy‐3,12‐bis(3,4,5‐trimethoxyphenyl)‐1,6,8,10,15,17‐hexaoxanaphtho[2′,3′: 6,7]cyclodeca[1,2‐b]naphthalene‐4,13(4H,13H)‐dione; 3), as well as eight known constituents, and their structures were elucidated by spectral analysis, including 2D‐NMR techniques.
Preparation of an Advanced Intermediate for the Synthesis of Stable Analogues of Guanofosfocin
Authors: George Tesmol G. , Szolcsányi Peter , Koenig Stefan G. , Paterson Duncan E. , Isshiki Yoshiaki , Vasella Andrea
Published: May 2004

The synthesis of C‐mannosyl‐guanosine 23, an advanced intermediate for the preparation of stable analogues of guanofosfocin, is described. This convergent approach features an improved Traube‐type synthesis of a 8‐substituted guanine, followed by ribosylation. NMR Studies show that the C‐mannopyranosyl moiety of 23 adopts a distorted 1C4 conformation while the nucleoside is predominantly syn‐oriented.
Injectable microparticle‐gel system for prolonged and localized lidocaine release. I. In vitro characterization
Authors: Chen Pen‐Chung , Park Yoon Jeong , Chang Li‐Chien , Kohane Daniel S. , Bartlett Robert H. , Langer Robert , Yang Victor C.
Published: May 2004

Current treatment protocol for postoperative pain is to infuse anesthetic solution around nerves or into the epidural space. This clinical practice is beset by the short duration of the anesthetic effect unless the infusion is continuous. Continuous infusion, however, requires hospitalization of the patients, thereby increasing medical costs. In addition, it also causes systemic accumulation of the drug. We reported herein a novel treatment for the postoperative pain by applying to the surgical site a biodegradable microsphere‐gel system for prolonged and localized release of encapsulated anesthetic drugs. This lidocaine‐containing biodegradable poly(D,L‐lactic acid) (PLA) microsphere system, although being established previously by other investigators, was hindered by a burst release and a followed rapid release of the drug within several hours in vitro. In this article, we demonstrated that by a step‐by‐step modification of the formulation, prolonged release of lidocaine, up to several days in vitro, could be achieved. Differential scanning calorimetry revealed a lower glass transition temperature for these lidocaine‐loaded microspheres comparing to that of lidocaine‐free microspheres. This decreased Tg explained for the tendency of the lidocaine‐loaded microspheres to physically fuse at higher temperatures. In vitro studies showed that microspheres, when loaded with 35% lidocaine, yielded a threefold increase in the degradation rate. The molecular weight of PLA of the drug‐loaded microspheres was reduced by 50% within a period of 1 month. Based on the results (of prolonged lidocaine release and rapid PLA microsphere degradation), this lidocaine‐loaded PLA microsphere system could offer a simple solution to the treatment of postoperative pain. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 412–419, 2004
Equitable list‐coloring for graphs of maximum degree 3
Authors: Pelsmajer Michael J.
Published: May 2004

Given lists of available colors assigned to the vertices of a graph G, a list coloring is a proper coloring of G such that the color on each vertex is chosen from its list. If the lists all have size k, then a list coloring is equitable if each color appears on at most ⌈|V(G)|/k⌉ vertices. A graph is equitably k‐choosable if such a coloring exists whenever the lists all have size k. Kostochka, Pelsmajer, and West introduced this notion and conjectured that G is equitably k‐choosable for k > Δ (G). We prove this for Δ(G) = 3. We also show that every graph G is equitably k‐choosable for k ≥ Δ(G)(Δ(G)−1)/2 + 2. © 2004 Wiley Periodicals, Inc. J Graph Theory 47: 1–8, 2004
Algorithms for minimum‐cost paths in time‐dependent networks with waiting policies
Authors: Dean Brian C.
Published: May 2004

We study the problem of computing minimum‐cost paths through a time‐varying network, in which the travel time and travel cost of each arc are known functions of one's departure time along the arc. For some problem instances, the ability to wait at nodes may allow for less costly paths through the network. When waiting is allowed, it is constrained by a (potentially time‐varying) waiting policy that describes the length of time one may wait and the cost of waiting at every node. In discrete time, time‐dependent shortest path problems with waiting constraints can be optimally solved by straightforward dynamic programming algorithms; however, for some waiting policies these algorithms can be computationally impractical. In this article, we survey several broad classes of waiting policies and show how techniques for speeding up dynamic programming can be effectively applied to obtain practical algorithms for these different problem variants. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(1), 41–46 2004
Intramedullary spinal cord astrocytomas in children
Authors: Townsend Nicole , Handler Michael , Fleitz Julie , Foreman Nicholas
Published: May 2004

Background

Intramedullary spinal cord astrocytomas are uncommon tumors in childhood. There is little information on therapy and outcome of astrocytomas in this location.

Procedure

A retrospective review was performed for the 10 children who were treated between 1996 and 2003 for spinal cord astrocytomas in our institution. Only one had metastatic disease. All ten patients underwent surgical resection, nine partial and one total. Eight had low‐grade tumors, and two high‐grade tumors. Two had surgery only, four had chemotherapy only, two had radiation only, and two had both radiation and chemotherapy.

Results

Progression free survival was 58% and survival was 68% at 4 years. Four patients had disease progression, of which three died. Both children with high‐grade astrocytomas died. Two of eight of the children with low‐grade astrocytomas of the cord recurred, one having received radiation as initial therapy and the other chemotherapy. The child, who relapsed after radiation, had a spastic quadriplegia from radiation myelitis and no salvage therapy was attempted. The four patients, all with low‐grade astrocytomas, who treated with chemotherapy alone, received carboplatin and vincristine. Of these four, three are in continuous remission and one relapsed, but was salvaged with radiation.

Conclusions

Chemotherapy and radiation did not benefit those with high‐grade astrocytomas of the spinal cord. Good outcomes can be achieved by conservative surgery for low‐grade astrocytomas of the cord when adjuvant therapy is given. Carboplatin and vincristine appeared to be effective, safe therapy for those with low‐grade astrocytomas of the cord. © 2004 Wiley‐Liss, Inc.
Pineal gland abnormalities in Langerhans cell histiocytosis
Authors: Grois N. , Prosch H. , Waldhauser F. , Minkov M. , Strasser G. , Steiner M. , Unger E. , Prayer D.
Published: May 2004

Background

The most common types of central nervous system (CNS) disease in Langerhans cell histiocytosis (LCH) comprise involvement of the hypothalamic‐pituitary region (HPR) and neurodegenerative changes in the cerebellum, basal ganglia or pons. In the review process of magnetic resonance images (MRI) from 129 LCH patients a high frequency of cysts within or large pineal glands was noted by chance.

Procedure

To prove whether this observation was specific for LCH or not, we compared MRI findings of the HPR in LCH patients with a control group of 55 non‐LCH patients with the same age and sex distribution.

Results

In LCH patients, the pineal gland was significantly larger and also the number of pineal cysts was significantly higher as compared to the control group. No difference was found regarding the size or frequency of cystic changes between patients who had received chemotherapy prior to the MRI and untreated patients. In the LCH patients, we further found a significant correlation of pineal gland enlargement with involvement of the HPR, but not with neurodegenerative changes. Analysis of melatonin (the principal hormone of the pineal gland) levels in 24 hr urine in 14 LCH patients did not reveal a melatonin deficiency or overproduction in the LCH group as compared to 6 normal controls.

Conclusions

The pineal gland is another site of possible CNS involvement in LCH. LCH CNS patients did not show an overt disturbance in melatonin levels. The role of the pineal gland in CNS LCH remains to be defined. © 2004 Wiley‐Liss, Inc.
Role of nucleophilic solvation and the mechanism of covalent bond heterolysis
Authors: Dvorko Genrih F. , Ponomareva Engelsine A. , Ponomarev Mykola E.
Published: May 2004

Based on data obtained mainly by the verdazyl method, the effects of a solvent on the rates of the heterolyses of 20 substrates (t‐BuCl, t‐BuBr, t‐BuI, 1‐AdBr, 1‐AdI, 1‐AdOTs, 1‐AdOPic, 1‐chloro‐1‐methylcyclopentane, 1‐bromo‐1‐methylcyclopentane, 1‐chloro‐1‐methylcyclohexane, 1‐bromo‐1‐methylcyclohexane, 2‐bromo‐2‐methyladamantane, p‐methoxyneophyl tosylate, 2‐chloro‐2‐phenylpropane, p‐methoxybenzotrichloride, Ph2CCl2, 7α‐bromocholesterol benzoate, 1‐chloro‐1‐phenylethane, Ph2CHBr, 3‐bromocyclohexene) were analyzed in a wide set of protic and aprotic solvents. The heterolysis rate of tertiary substrates decreases with increase in solvent nucleophilicity, but for secondary substrates it does not depend on solvent nucleophilicity. The negative effect of nucleopilic solvation is caused by the solvation of a contact ion pair, which appears before the limiting step. The lack of nucleophilic solvent assistance indicates that a solvent‐separated ion pair of substrates appears after the limiting step. The limiting step involves the interaction of a contact ion pair with a solvent cavity, resulting in the formation of a cavity‐separated ion pair of substrates. Copyright © 2004 John Wiley & Sons, Ltd.
Kinetics of oxidation of acidic amino acids and their monoamides by N‐chloroarylsulphonamides in aqueous acidic medium
Authors: Gowda B. Thimme , Shetty Mahesha
Published: May 2004

Twelve sodium salts of N‐chloroarylsulphonamides were employed as oxidants for studying the kinetics of oxidation of two acidic amino acids (aspartic and glutamic acid) and their monoamides (aspargine and glutamine) in aqueous acidic medium under various conditions, to see how the oxidative strength of these reagents vary with substitution. The sodium salts of N‐chloroarylsulphonamides employed are of the general formulae i‐X‐C6H4SO2NaNCl·xH2O (where i‐X = 4‐C2H5, 4‐F, 4‐Cl or 4‐Br) and i‐X‐j‐Y‐C6H3SO2NaNCl·xH2O [where i‐X‐j‐Y = 2,3‐(CH3)2, 2,4‐(CH3)2, 2,5‐(CH3)2, 2‐CH3‐4‐Cl, 2,4‐Cl2 and 3,4‐Cl2]. The reactions show second‐order kinetics in [oxidant], fractional order in [amino acid] and an inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. Mechanisms in conformity with the observed kinetics are discussed. The effective oxidizing species of the oxidants is Cl+ in different forms. The oxidizing strengths of N‐chloroarylsulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of electron‐withdrawing groups such as halides to the benzene ring eases the release of Cl+ from the reagent and hence increases the oxidizing strengths of the N‐chloroarylsulphonamides. The effect of substituents on Ea of the reactions was analysed by optimising Ea with reference to log A, and log A with reference to Ea of the parent oxidant. Copyright © 2004 John Wiley & Sons, Ltd.
Reactions of carbocations with water and azide ion: calculation of rate constants from equilibrium constants and distortion energies using No Barrier Theory
Authors: Guthrie J. Peter , Pitchko Vladimir
Published: May 2004

Rate constants for the reaction of water or azide ion with various substituted benzylic carbocations can be calculated from the equilibrium constants for cation formation and distortion energies by means of the No Barrier Theory. Rate constants for the water reactions span 10 orders of magnitude. Most but not all of the azide reactions are diffusion controlled. The rate constants, and in particular those less than diffusion controlled, were successfully calculated. The set of equilibrium constants available from the literature was supplemented using alkyl chloride hydrolysis equilibrium constants and relative cation formation equilibrium constants derived from DFT/continuum calculations. The model used for these reactions allows for the entropic cost of bringing solutes together, the desolvational cost of losing hydrogen bonding solvation by water and the cost of moving the aryl ring through the solvent as the central atom changes from sp2 to sp3 hybridization and from planar to pyramidal geometry. Copyright © 2004 John Wiley & Sons, Ltd.
Mononuclear Co(III)‐complex promoted phosphate diester hydrolysis: dependence of reactivity on the leaving group
Authors: Padovani Michela , Williams Nicholas H. , Wyman Paul
Published: May 2004

The TrpnCo(III)(OH)(OH2)‐promoted hydrolysis of a range of methyl aryl phosphate diesters was investigated at 37°C and I = 0.1 M (NaClO4). The pH–rate profile confirms that the aqua‐hydroxy form of the complex is the only kinetically significant ionic form. At pH 6.9, all the reactions are first order in both diester and Co(III) complex. Plotting the second‐order rate constant for Co(III) complex‐promoted hydrolysis against the pKa of the leaving aryloxy group revealed a bent LFER indicating a change in rate‐limiting step. This is discussed in terms of either a change from rate‐limiting hydrolysis to rate‐limiting binding or the presence of a phosphorane intermediate. Copyright © 2004 John Wiley & Sons, Ltd.
A zinc(II) complex‐conjugated polymer for selective recognition and separation of phosphates
Authors: Aoki Shin , Jikiba Akiko , Takeda Kei , Kimura Eiichi
Published: May 2004

A new polymer, Zn2+–cyclen complex‐conjugated polymer 4 (cyclen = 1,4,7,10‐tetraazacyclododecane), was synthesized by copolymerization of a Zn2+–(4‐vinyl)benzylcyclen complex (3, ZnL2) with ethylene glycol dimethacrylate (EGDMA). The contents of the zinc(II) ions in Zn2+–cyclen polymer 4 were determined as 36–42 μmol g−1, utilizing a Zn2+‐selective fluorophore, dansylamidoethylcyclen 10 (L3). It was found that 31% of deoxyadenosine 5′‐monophosphate (5′‐dAMP) (50 μM) is adsorbed on 4 (corresponding to 50 μM) in 20 mM HEPES (pH 7.0) with I = 0.1 (NaNO3) at 25°C. The apparent complexation constants for the 1:1 complex of ZnL2 on 4 with 5′‐dAMP and 4‐NPP, logKapp(ZnL–S2−) (S2− denotes a phosphomonoester dianion), at pH 7.0 and 25°C were determined as 4.1±0.1, which was larger than that (3.5) for the 1:1 complex of 3 (ZnL2) with 5′‐dAMP in homogeneous aqueous solution at pH 7.0 and 25°C. Deoxyadenosine (dA) and adenosine 3′,5′‐cyclic‐monophosphate (3′,5′‐cAMP), a cyclic phosphodiester monoanion, were negligibly adsorbed on Zn2+–cyclen polymer 4, implying that 4 interacts selectively with phosphomonoester dianions. For reference, Zn2+‐free polymer 8 (prepared from 4) and control polymer 9 (prepared by copolymerization of styrene with EGDMA) hardly adsorbed 5′‐dAMP, dA and 3′,5′‐cAMP. High‐performance liquid chromatography (HPLC) of mononucleotides such as 5′‐dAMP, cytidine 5′‐monophosphate (5′‐CMP), guanosine 5′‐monophosphate (5′‐GMP), and thymidine 5′‐monophosphate (5′‐dTMP) was achieved using 4 as a stationary phase and continuous gradient elution with 10:90 MeOH–1 mM HEPES (pH 7.0) and 10:90 MeOH–1 mM HEPES+10 mM (NH4)2HPO4 (pH 7.0). As expected, the retention times of mononucleotides were larger than those of the corresponding nucleosides, owing to the Zn2+‐phosphate interactions. These results indicated that Zn2+–cyclen‐conjugated polymer 4 affords a strong methodology to detect and separate biologically important phosphates. Copyright © 2004 John Wiley & Sons, Ltd.
Investigation of the sulfuryl transfer step from substrate to enzyme by arylsulfatases
Authors: Gibby Stuart G. , Younker Jarod M. , Hengge Alvan C.
Published: May 2004

The reactions of the arylsulfatase A (ASA) from Helix pomatia and that from Aerobacter aerogenes with p‐nitrophenyl sulfate were examined by determination of the pH dependence of Vmax/Km and by measurement of kinetic isotope effects. Both enzymes exhibit bell‐shaped pH–rate dependences for Vmax/Km. The ASA from Helix pomatia exhibits a more acidic pH optimum (pH 4–5) than the ASA from Aerobacter aerogenes (pH ∼7). The sulfuryl transfer from substrate to enzyme is general acid‐assisted in both enzymes, but isotope effects indicate differences in the synchronicity of protonation with SO bond fission. In the reaction of the Helix pomatia enzyme, protonation is synchronous with bond fission and the leaving group is fully neutralized in the transition state. In the reaction catalyzed by the Aerobacter aerogenes ASA, protonation of the leaving group lags behind bond fission and the leaving group bears a partial negative charge in the transition state. Copyright © 2004 John Wiley & Sons, Ltd.
Rate and equilibrium constants for hydrolysis and isomerization of (E)‐ and (Z)‐p‐methoxybenzaldehyde oximes
Authors: O'Ferrall Rory A. More , O'Brien Deirdre
Published: May 2004

The interconversion and hydrolysis of (E)‐ and (Z)‐oximes of p‐methoxybenzaldehyde in aqueous solutions of perchloric acid have been studied in the acid concentration range from pH 3 to 11 M. Kinetic measurements confirm that isomerization and hydrolysis proceed through a common tetrahedral intermediate T0. At low acid concentrations, attack of water on the protonated oxime is rate‐determining in the hydrolysis reaction and no separate isomerization is observable. However, as the acid concentration increases the attack of water becomes faster than loss hydroxylamine from T0 and E to Z isomerization is observable as a faster reaction in competition with hydrolysis. From kinetic and equilibrium measurements a comprehensive set of rate and equilibrium constants for protonation, hydrolysis and hydration of (E)‐ and (Z)‐oximes is derived. For the neutral oximes KT = [E]/[Z] = 8 and for the protonated oximes pKa = −0.55 and 0.80 for the E and Z isomers, respectively. By combining these values with measurements of oxime formation from p‐methoxybenzaldehyde and hydroxylamine, including Kadd = [T0]/[aldehyde][NH2OH] = [T0]/[oxime] = 1.8, values of pKR = −3.65 and −5.90 and K = 6.3 × 10−5 and 7.9 ×  10−6 for (E)‐ and (Z)‐oximes may also be derived. The values of pKa, pKR and K for the oximes are compared with corresponding values for p‐methoxybenzaldehyde and its hydrate (≡ T0). Copyright © 2004 John Wiley & Sons, Ltd.
Novel aromatic polyamides bearing pendent diphenylamino or carbazolyl groups
Authors: Hsiao Sheng‐Huei , Chen Chien‐Wei , Liou Guey‐Sheng
Published: May 2004

Two new diamines, 2,4‐diaminotriphenylamine (3) and N‐(2,4‐diaminophenyl)carbazole (4), were synthesized via the cesium fluoride‐mediated aromatic substitution reactions of 1‐fluoro‐2,4‐dinitrobenzene with diphenylamine and carbazole, followed by palladium‐catalyzed hydrazine reduction. Amorphous and soluble aramids having pendent diphenylamino and carbazolyl groups were prepared by the phosphorylation polycondensation of aromatic dicarboxylic acids with diamines 3 and 4, respectively. The aramids derived from diamine 3 had sufficiently high molecular weights to permit the casting of flexible and tough films. They exhibited excellent mechanical properties and moderately high softening temperatures in the 221–298 °C range. However, the reactions of diamine 4 with aromatic diacids gave relatively lower molecular weights products that could not afford flexible films. For a comparative purpose, the parent aramids derived from m‐phenylenediamine and aromatic diacids were also prepared and characterized. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3302–3313, 2004
Structure of a poly(2,5‐benzimidazole)/phosphoric acid complex
Authors: Cho Jaedong , Blackwell John , Chvalun Sergei N. , Litt Morton , Wang Yuan
Published: May 2004

As‐cast films of poly(2,5‐benzimidazole) exhibit uniplanar orientation in which the planes of the aromatic rings lie parallel to the film surface. Upon doping with phosphoric acid, the original crystalline order is lost, but the doped film can be stretched to produce films with uniaxial orientation. After thermal annealing at 540 °C, nine Bragg reflections are resolved in the fiber diagram, and these are indexed by an orthorhombic unit cell with the dimensions a = 18.1 Å, b = 3.5 Å, and c = 11.4 Å, containing four monomer units of two chains. The absence of odd‐order 00l reflections points to a 21 chain conformation, which is probably planar so that the aromatic units can be stacked along the b axis. The water and phosphoric acid contents of the crystalline structure cannot be determined exactly because of the presence of extensive amorphous regions that probably have different solvation. The best agreement between the observed and calculated intensities is for an idealized structure containing two phosphoric acids and two water molecules per unit cell. However, the phosphoric acid is probably present mainly in the form of pyrophosphoric acid and its higher oligomers. In addition, the X‐ray data are consistent with a more disordered structure containing chains with random (up and down) polarity and a lack of c‐axis registry. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2576–2585, 2004
The Flow Patterns and Wall Stresses in a Louvered‐Wall Moving Granular Filter Bed of Quartz Sand
Authors: Chou Chuen‐Shii , Chen Huang‐Hsiang
Published: May 2004

The flow patterns and wall stresses in a two‐dimensional louvered moving granular filter bed of quartz sand were investigated. The flow pattern histories of granular solids in the filter bed were recorded using a digital camcorder and a pressure gauge for simultaneously measuring the normal stresses as well as shear stresses of the granular solids. The static wall stress distributions produced by the granular solids were measured, and agreed with a theoretical prediction formed using the differential slice and Runge‐Kutta (order four) methods. The variations in the dynamic wall stresses with time in a moving granular filter bed were obtained and the effect of the louver angle upon the flow patterns and wall stresses was also investigated. Employing the results obtained by stress measurements and image processing, the wall pressure pulsation phenomena in a moving granular filter bed may be further understood. The results reported here provide fundamental information for the design of moving granular filter beds to act as high‐temperature flue gas cleanup filters.
A combined imaging, microthermal and spectroscopic study of a multilayer packaging system
Authors: Woodward I. , Ebbens S. , Zhang J. , Luk S. , Patel N. , Roberts C.J.
Published: May 2004

The effectiveness of a packaging solution for the pharmaceutical and food industry is dependent on the integrity of the constituent layers and the interfaces formed between them. The deconvolution and analysis of the many intimate layers found in packaging is analytically challenging, requiring techniques capable of identifying sub‐micron regions. Here we have characterized the chemical and physical nature of the layers in a multilayer packaging system along with the interfaces, using a combination of high‐resolution atomic force microscopy (AFM), microthermal analysis using scanning thermal microscopy (SThM), and Fourier transform infrared (FT‐IR) spectroscopy. In particular, localized thermal analysis is shown to reveal the thermal transitions of the individual layers, but it was found that care must be exercised when melting through one layer to the next, as this can result in overestimates of melting temperatures of the underlying layer due to excess power loss from the SThM probe to the already molten top layer surrounding the probe. Copyright © 2004 John Wiley & Sons, Ltd.
The effect of high‐pressure food processing on the sorption behaviour of selected packaging materials
Authors: Caner C. , Hernandez R.J. , Pascall M. , Balasubramaniam V.M. , Harte B.R.
Published: May 2004

The sorption behaviour and flavour‐scalping potential of selected packaging films in contact with food simulant liquids (FSLs) (ethanol and acetic acid solutions) were evaluated after high‐pressure processing (HPP). The films used were monolayer polypropylene (PP), a multilayer (polyethylene/nylon/ethylene vinyl alcohol/polyethylene: PE/nylon/EVOH/PE), film and a metallized (polyethylene terephthalate/ethylene–vinyl acetate/linear low‐density polyethylene: metallized PET/EVA/LLDPE) material. D‐limonene was used as the sorbate and was added to each of the FSLs. After HPP treatment at 800 MPa, 10 min, 60°C, the amount of D‐limonene sorbed by the packaging materials and the amount remaining in the FSL was measured. Untreated controls (1 atm, 60°C and 40°C) were also prepared. Extraction of the D‐limonene from the films was performed using a purge/trap method. D‐limonene was quantified in both the films and the FSL, using gas chromatography (GC). The results showed that D‐limonene concentration, in both the films and the food simulants, was not significantly affected by HPP, except for the metallized PET/EVA/LLDPE. Significant differences in D‐limonene sorption were found in comparison with the control pouches. The results also showed that changes in temperature significantly affected the sorption behaviour of all films. Copyright © 2004 John Wiley & Sons, Ltd.
Stress recovery during an ocean boat race
Authors: Gunnarsson Lars‐Gunnar , Bäck Hans , Jones Ian , Olsson Tommy
Published: May 2004

The aim was to study the effects of intense and sustained stress associated with a several months long endurance test with special emphasis on the biology of recovery. Biological stress markers of ‘catabolism’ (cortisol in saliva and HbA1c in blood) and ‘anabolism’ (testosterone in saliva) were followed in crewmembers during a 9‐month around the world sailing race. During sustained mental stress the diurnal cortisol curve was flattened, HbA1c was at the upper part of the normal range and testosterone levels were low. In the latter part of the race the crew mastered the situation and the stress markers were normalized. Our longitudinal approach disclosed a striking shift in the profile of stress markers from a ‘catabolic’ to an ‘anabolic’ state, corresponding to a decline of mental stress. Copyright © 2004 John Wiley & Sons, Ltd.
Update on transcervical sterilization
Authors: Neuwirth R.S.
Published: May 2004

Transcervical sterilization techniques as of 1980 are reviewed. A personal and literature search is reported on developments between 1980 and 1992. The potential of endometrial ablation for a transcervical method of fertility control is explored. An appraisal of the more promising methods for future study is made, including silastic tubal plugs, quinacrine, Femcept delivery of an iodine mixture and endometrial ablation.
THE FRANCHISE FACTOR IN THE DEFEAT OF THE IRISH PARLIAMENTARY PARTY, 1885–1918
Authors: McCONNEL JAMES
Published: May 2004

This article examines Irish nationalist attitudes towards electoral reform between 1885 and 1918. It argues that before 1917 mainstream Irish nationalist opinion attached little importance to the franchise, being instead more concerned about the consequences for home rule if the number of Irish parliamentary seats was reduced through redistribution. However, the introduction of wartime legislation to reform the franchise and registration system repoliticized electoral reform in nationalist Ireland. While the Irish parliamentary party vociferously protested at the coalition government's belated attempt to redistribute Irish constituencies, its critics (a coalition of heterodox nationalists, socialists, and suffragettes) accused it of deliberately conspiring to exclude Ireland from the ‘fourth’ reform bill because the young men and women it would enfranchise intended to vote for Sinn Fein. This article argues that the concerns of the Irish party regarding redistribution were genuine and legitimate, while the conspiracy theory was essentially a propaganda device. None the less, the theory gained widespread attention because its underlying assumption about the voting behaviour of the new electorate was shared not only by its exponents, but by sections of the press, the British administration in Ireland, and the Irish party itself. Indeed, so convinced was the party that the cleavage in Ireland was as much generational as ideological that ultimately the franchise was a factor in its defeat at the 1918 general election.
GERMAN FRESCO PAINTING AND THE NEW HOUSES OF PARLIAMENT AT WESTMINSTER, 1834–1851
Authors: WINTER EMMA L.
Published: May 2004

In 1841, a select committee proposed that the houses of parliament at Westminster, which were being rebuilt in the aftermath of the fire of 1834, be decorated with fresco paintings and that Ludwig I of Bavaria's patronage of the arts be used for guidance. Both recommendations were surprising, for Britain had neither any tradition of public painting, nor any obvious ties with the south German state. This article explains why the committee was so sensible to Ludwig's example, and what it hoped to achieve by introducing fresco painting into Britain. The scheme was to serve not only as the means of establishing a national school of painting that could compete with the modern German school, but also as an integral part of a broader endeavour to construct a national culture in Britain that was both patriotic and socially inclusive. The national potential of this state-sponsored scheme of art promotion came to be undermined, however, by the emergence of both political and religious hostility to such German-style patronage in Britain. The article highlights not only the crucial role played by German art in the endeavour to construct a national culture in Britain, but also the continuing potency of religion as an element of British national identity during the first decade of Victoria's reign. It also draws attention to the fundamental role played by Prince Albert in his capacity as president of the fine arts commission, and the extent to which the debate surrounding the commission's proceedings provided the essential context for both the emergence and reception of the Pre-Raphaelite brotherhood in 1848–50.
CLERGY JPs IN ENGLAND AND WALES, 1590–1640
Authors: HAIGH CHRISTOPHER , WALL ALISON
Published: May 2004

In the 1621 parliament members of the House of Commons clashed with the king over the issue of clergy as JPs: there were suggestions that no clergyman should sit as a JP, or that only bishops and deans should be appointed. Why were there complaints at that time, and were they justified? Was the nomination of clergy as justices an element in ‘the rise of clericalism’? This analysis of clergy JPs between 1590 and 1640 shows that they had been increasing slowly in number from 1590, and more rapidly towards 1617 under Lord Chancellor Ellesmere. But the major expansion in their ranks came under his successors Francis Bacon 1617 to 1621, and especially Bishop John Williams 1621 to 1625. However, there was no systematic central policy behind appointments, and local interests and the normal processes of patronage were important. Perhaps precedence among the justices and the exercise of secular authority by clerical JPs were sometimes troublesome issues. But, despite continuing complaints from MPs, the proportion of clergy to lay JPs was always small – at its highest in 1626, with 7·6 per cent. Thereafter Lord Keeper Thomas Coventry allowed the clerical presence to decline, both absolutely and proportionately. If there was a ‘rise of the clergy’ after 1625, clergy JPs were not part of it.
RECENT PERSPECTIVES ON EARLY MODERN LONDON
Authors: HARDING VANESSA
Published: May 2004

Recent writing on early modern London offers new perspectives on a wide range of topics. Interest in the literary and cultural is particularly strong, and much attention has been given to John Stow, London's sixteenth-century historian. This review discusses recent work on three themes prominent in Stow's Survey of London (1598), and its later editions: the character of religious life in post-Reformation London; the importance of place and space to the experience of the city; and the question of civic and business morality in a changing world.
‘THE ONES WHO HOLD UP THE WORLD’: NATIVE AMERICAN HISTORY SINCE THE COLUMBIAN QUINCENTENNIAL An unsettled conquest: the British campaign against the peoples of Acadia. By Geoffrey Plank. Philadelphia: University of Pennsylvania Press, 2001. Pp. 239. ISBN 0-8122-3571-1. £21.00. Blue Jacket: warrior of the Shawnees. By John Sugden. Lincoln, NB: University of Nebraska Press, 2000. Pp. xvi+250. ISBN 0-8032-4288-3. £19.95. The Cambridge history of the native peoples of the Americas, II: Mesoamerica. Edited by Richard E. W. Adams and Murdo J. MacLeod. Two parts. Cambridge: Cambridge University Press, 2000. Pp.xv+571, xv+455. ISBN 0-521-652905-7. £90.00 (complete set).
Authors: MANCALL PETER C.
Published: May 2004

The quincentennial of Christopher Columbus's first voyage in 1992 generated an enormous outpouring of both emotion and scholarship. At times, it seemed that the emotional issues prevailed. Unlike earlier generations of scholars who had celebrated Columbus's achievements, the cohort of 1992 mostly attacked the Admiral of the Ocean Sea. As the historian Kenneth Maxwell put it, ‘Columbus was mugged on the way to his own party.’ By the time many commentators got through with him, Columbus had become responsible for precipitating centuries of slavery, environmental degradation, and ethnic cleansing in the Americas. He became the antichrist of a secular United States.
Temporal patterns of change in the necrophagous hyperbenthic zooplankton community of Lobster Bay, Cape d'Aguilar Marine Reserve, Hong Kong
Authors: Lee Christine N.W. , Morton Brian
Published: May 2004

Crab-baited traps, with a 5-mm diameter opening, were deployed 90 mm off the seabed monthly at Lobster Bay, Hong Kong, for one year between 1998 and 1999. Visitors drawn to the traps were mainly species of Ceradocus (Gammaridea: Melitidae), Tisbe (Harpacticoida: Tisbidae) and Nebalia (Leptostraca: Nebaliacea). Apart from Ceradocus sp., all were scavengers with catches using baited traps significantly exceeding unbaited controls. Ceradocus sp. was apparently drawn to traps for refuge. The trapped scavenger community composition changed with deployment duration in the presence of bait. Nebalia sp., Neanthes cricognatha (Polychaeta: Nereidae) and Lepedepecreum sp. (Gammaridea: Lysianassoidea) were identified mostly two/three-days post-deployment, exhibiting a potential preference for rotten organic matter. Seasonal catches were also identified for all three visitors with maxima between October 1998 and April 1999. Such seasonal patterns might be related to either turbulence destabilizing the substratum during this period or life cycle patterns in the study area.
Ecology of sponge assemblages (Porifera) in the Wakatobi region, south-east Sulawesi, Indonesia: richness and abundance
Authors: Bell James J. , Smith David
Published: May 2004

The influence of sedimentation, depth and substratum angle on sponge assemblages in the Wakatobi region, south-eastern Sulawesi, Indonesia was considered. Sponge assemblages were sampled from two reef localities. The first reef (Sampela) was highly impacted by high sedimentation rates with fine sediment particles that settle slowly, while the second (Hoga) experienced only fast settling coarse sediment with lower overall sedimentation rates. Sponge assemblages were sampled (area occupied and numbers) on the reef flat (0 m) and at 5 (reef crest), 10 and 15 m (15 m at Hoga only). Some significant (P<0·001) differences were observed in the area occupied and the number of sponge patches between surface angles and sites. Significantly lower (t>4·61, df=9, P<0·001) sponge numbers, percentage cover and richness were associated with the reef flat at both sites compared with all other depths at each site, with the exception of abundance of sponges on the reef flat at Sampela, which was much greater than at any other depth sampled. Species richness increased with depth at both sites but differences between surface angles were only recorded at Sampela, with higher species richness being found on vertical, inclined and horizontal surfaces respectively. A total of 100 sponge species (total area sampled 52·5 m2) was reported from the two sites, with 58 species found at Sampela and 71 species at Hoga (41% of species shared). Multi-dimensional scaling (MDS) indicated differences in assemblage structure between sites and most depth intervals, but not substratum angles. A number of biological (e.g. competition and predation) and physical (e.g. sedimentation and aerial exposure) factors were considered to control sponge abundance and richness. Unexpectedly a significant (F1,169=148·98, P<0·001) positive linear relationship was found between sponge density and area occupied. In areas of high sponge coverage, the number of patches was also high, possibly due to fragmentation of large sponges produced as a result of predation and physical disturbance. The MDS results were also the same whether sponge numbers or percentage cover estimates were used, suggesting that although these different approaches yield different sorts of information, the same assemblage structure can be identified.
Diel catch variations in a shallow-water fish assemblage at Duće Glava, eastern Adriatic (Croatian Coast)
Authors: Dulčić Jakov , Fencil Megan , Matić-Skoko Sanja , Kraljević Miro , Glamuzina Branko
Published: May 2004

An assemblage of shallow-water fish was sampled with a small beach seine over monthly 24-h periods between April 2000 and March 2001 at the sandy beach Duće Glava in the eastern Adriatic. Monthly sets of samples were divided into day and night catches to examine the stability of diel differences in assemblage structure over a 1-y period. A total of 61 species was caught, of which six were exclusively diurnal and 12 were nocturnal. According to abundance and biomass of individuals during day and night, the most abundant species were categorized into several groups. Ophidion rochei was exclusively nocturnal, while Nerophis ophidion and Echiichthys vipera were mostly nocturnal. Diplodus annularis and Mullus surmuletus were slightly nocturnal. Diplodus vulgaris, Pomatoschistus marmoratus and Atherina boyeri lacked a diel pattern. Sardina pilchardus, Lithognathus mormyrus, Atherina hepsetus, Sarpa salpa and Mullus surmuletus abundance peaked for a few months, probably related to timing of spawning and recruitment. At the assemblage level, the diel per cent similarity index indicates that there were major differences between the day and night assemblages in April, September, March, and August with respect to number of individuals and September, October, May and March with respect to biomass.