bluuebunny/crossref_metadata_2025 huggingface dataset:
New bound electronic states of NH+
Authors: Amero José M. , Vázquez Gabriel J.
Published: June 2004

Ab initio MRD‐CI electronic structure calculations were carried out on the NH+ cation. A basis set of DZ + POL quality augmented with Rydberg and bond functions was employed, together with an extensive treatment of electron correlation. We find four new bound electronic states of NH+, namely, three doublets (2Δ, 2Σ+, 2Σ+) and one sextet (6Π). A fifth bound electronic state, a quartet (4Π) that was reported schematically in an early SCF study (Liu, H. P. D.; Verhaegen, G. J Chem Phys 1970, 53(2), 735), is calculated for the first time over a wide range of NH distances. Electronic energies, potential energy curves, and spectroscopic constants are reported for these five states. Vertical and adiabatic excitation and ionization energies are reported, as well as vertical de‐excitation energies for emission from the novel states to lower‐lying bound states. The potential energy curve of NH2+ (X1Σ+) was also calculated to aid in the discussion of a Rydberg bound state of NH+. It is hoped that the information reported in this article will be helpful in guiding the experimental detection of these species. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Pyrrole anion addition to carbon disulfide: An ab initio study
Authors: Kobychev Vladimir B. , Vitkovskaya Nadezhda M. , Zaytseva Irina L. , Trofimov Boris A.
Published: June 2004

The reaction pathways of pyrrole‐1‐ and pyrrole‐2‐carbodithioate anions formation were studied using the MP2/6‐31+G* approach. No activation barrier was found on the potential energy surface for the former. By contrast, there is a significant activation barrier on the C2‐adduct formation pathway. This can cause a kinetic formation of the thermodynamically less favorable N‐adduct from unsubstituted pyrrole and CS2, while a relative instability of 2(5)‐methylpyrrole‐1‐carbodithioates results in C2‐ and C3‐adducts. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
TUNCUR: Sequential codes for semiempirical quantum chemical calculations of tunneling current
Authors: Zayets Valentin A. , Sheka Elena F.
Published: June 2004

TUNCUR codes are aimed at a self‐consistent calculation of both equilibrated structures and electronic properties of a sample and scanning tunneling microscopy (STM) tip altogether with the tunneling current between them in the framework of the same computational scheme. Both objects are modeled by atomic clusters. Quantum chemical calculations in TUNCUR codes are provided by sequential programs, CLUSTER‐Z1 and CLUSTER‐Z2, which perform Hartree–Fock self‐consistent field semiempirical calculations in the valence sp‐ and spd‐basis, respectively. TUNCUR consists of three main blocks that provide calculations of STM recordings in two modes of operation as well as computing local density of states. All calculations are performed over a grid of variable parameters. There are two additional blocks for calculations of both the current Z‐dependence and volt‐ampere characteristic of the tunneling gap. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Enhanced post‐source decay and cross‐ring fragmentation of oligosaccharides facilitated by conversion to amino derivatives
Authors: Muzikar Jan , Mechref Yehia , Huang Yunping , Novotny Milos V.
Published: June 2004

Post‐source decay (PSD) fragmentation of chemically or enzymatically produced aminoglycans has been evaluated through matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry. Conversion of native glycans to their respective aminoglycan derivatives improved detection sensitivity of the usual fragments and promoted cross‐ring fragmentation of linear oligosaccharides, facilitating linkage recognition. The cross‐ring fragmentations for both dextrin and dextran oligosaccharides were not limited to the reducing‐end glucose moiety, as they were extended throughout the entire molecule. When the amino group was generated for N‐glycans derived from three different glycoproteins, an enhancement of PSD was observed, without a significant extent of cross‐ring fragmentation. Copyright © 2004 John Wiley & Sons, Ltd.
Electrospray ionization mass spectrometric analysis of noncovalent complexes between DNA and polyamides containing N‐methylpyrrole and N‐methylimidazole
Authors: Zhou Jiang , Yuan Gu
Published: June 2004

Electrospray ionization mass spectrometry was utilized to investigate the noncovalent complexes between novel polyamides and DNA containing the TCCT sequence. We analyzed the noncovalent binding of the polyamides with the DNA and assessed their relative affinities and stoichiometry. The results confirm that hairpin polyamides have higher binding affinities than three‐ring polyamides. The hairpin polyamide (PyPyPyPyγPyImImPyβDp) has the highest affinity, and the β‐linked polyamide (PyPyPyβImImImβDp) shows a dominant 1:2 binding stoichiometry. Two groups of competition experiments were undertaken to compare the binding affinities of the duplex DNA with different polyamides directly. The affinity scale thus obtained for the group‐1 polyamides is PyPyPyPyγPyImImPyβDp > PyPyPyβImImImβDp ≈ PyPyPyγImImImβDp ≫ PyPyPyβDp > PyImImβDp ≈ ImImPyβDp, and the order for the group‐2 polyamides is PyPyPyγImImImβDp > PyPyPyγImImImβOEt > PyPyPyγImImImβCOOH. Copyright © 2004 John Wiley & Sons, Ltd.
Porous polymer monolith for surface‐enhanced laser desorption/ionization time‐of‐flight mass spectrometry of small molecules
Authors: Peterson Dominic S. , Luo Quanzhou , Hilder Emily F. , Svec Frantisek , Fréchet Jean M. J.
Published: June 2004

Porous poly(butyl methacrylate‐co‐ethylene dimethacrylate), poly(benzyl methacrylate‐co‐ethylene dimethacrylate), and poly(styrene‐co‐divinylbenzene) monoliths have been prepared on the top of standard sample plates used for matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry and the modified plates were used for laser desorption/ionization mass spectrometry (LDI‐MS). The hydrophobic porous surface of these monoliths enables the transfer of sufficient energy to the analyte to induce desorption and ionization prior to TOFMS analysis. Both UV and thermally initiated polymerization using a mask or circular openings in a thin gasket have been used to define spot locations matching those of the MALDI plates. The desorption/ionization ability of the monolithic materials depends on the applied laser power, the solvent used for sample preparation, and the pore size of the monoliths. The monolithic matrices are very stable and can be used even after long storage times in a typical laboratory environment without observing any deterioration of their properties. The performance of the monolithic material is demonstrated with the mass analysis of several small molecules including drugs, explosives, and acid labile compounds. The macroporous spots also enable the archiving of samples. Copyright © 2004 John Wiley & Sons, Ltd.
Statistical estimation of link availability and its impact on routing in wireless ad hoc networks
Authors: McDonald A. Bruce , Znati Taieb F.
Published: June 2004

In this paper, an analytical framework is developed and validated via simulation for statistical estimation of the evolution of the separation between a pair of mobile nodes in an ad hoc network. Simulation results demonstrate that path selection based on minimization of the product of the link statistic significantly outperforms minimum‐hop and fixed threshold‐based ‘path‐stability’ schemes. A hierarchical mobility model integrating the dynamic effects of velocity, group movement and geographic scope is used to generalize the results. Another significant result is the performance enhancements hold in large networks irregardless of the assumptions used for statistical estimation. The effect of merging many independent groups appears to restore independent mobility. Finally, results show that at the highest mobility levels, 90% of the longest surviving paths fail within 60 s. None of the strategies approach this optimal value. This important result suggests that optimal predictive mechanisms alone are insufficient to ensure scalable routing in ad hoc networks. Copyright © 2004 John Wiley & Sons, Ltd.
Average error rate of NCFSK with multi‐branch post‐detection switched diversity
Authors: Yang Hong‐Chuan , Alouini Mohamed‐Slim , Simon Marvin K.
Published: June 2004

We investigate the performance of non‐coherent frequency shift keying (NCFSK) with multi‐branch post‐detection switched diversity systems. After an appropriate statistical description of the square‐law detector output, we derive generic formulas for the symbol/bit error probability of NCFSK for both switch and stay combining (SSC) and switch and examine combining (SEC) schemes. We show that while the SSC scheme does not benefit from more than two diversity paths when the paths are identically distributed, the error performance of SEC improves as the number of antenna paths increases. We consider two detection schemes for NCFSK, one for M‐ary FSK and another limited to only BFSK. We show that the second scheme leads to lower error probability performance when both are used to detect binary signals. The mathematical formalism is illustrated with a number of selected numerical examples. Copyright © 2004 John Wiley & Sons, Ltd.
Mobility assessment on‐demand (MAOD) routing protocol for mobile ad hoc networks
Authors: Chang Ruay‐Shiung , Chen Wei‐Wen
Published: June 2004

In ad hoc wireless networks, the high mobility of hosts is usually a major reason for link failures. The general ‘shortest path’ based routing protocols may not lead to stable routes. In this paper, we propose a mobility assessment on‐demand (MAOD) routing protocol to select a stable route in order to enhance system throughput and performance. An error count parameter is used to judge whether a host is highly mobile. The proposed MAOD routing protocol is an on‐demand routing protocol similar to dynamic source routing (DSR). The difference between MAOD and DSR is in the path selection method. Because MAOD takes the mobility of hosts into consideration, it will select a more stable and reliable path than DSR. In comparison, DSR only considers whether this route is a shortest path or not. Finally, the system performance is analyzed by using the global mobile simulation (GloMoSim) simulator. We can observe that MAOD routing protocol outperforms DSR routing protocol especially in the high mobility environment. Copyright © 2004 John Wiley & Sons, Ltd.
High‐capacity resource sharing schemes for broadband wireless networks
Authors: Andreadis Alessandro , Benelli Giuliano , Giambene Giovanni , Pasqualetti Veronica
Published: June 2004

The unique capabilities of new cellular systems are expected to provide users with integrated multimedia services. Since the air interface still represents the system bottleneck, this paper proposes novel scheduling techniques to integrate efficiently the support of real‐time traffic (i.e. voice and video) and data bursty traffic under quality of service (QoS) guarantees. Prioritization among traffic classes is adopted and a polling service discipline is employed within a class, where the permission rights of each traffic source are determined on the basis of token bucket regulators. Two polling‐based approaches are compared to serve the sources of a class: (i) when a source is enabled to transmit, a burst of packets is sent at once; (ii) within the time interval destined to a traffic class, a cyclic service of the sources is allowed on a packet basis. With realistic assumptions on both radio channel conditions and protocol signaling overhead, this paper compares these two different approaches and the dynamic slot assignment++ (DSA++) scheme appeared in the literature. The obtained results highlight that our second scheme (case ii) allows increasing the number of supported video traffic sources of many units with respect to DSA++. Finally, an analytical approach has been proposed for our second polling scheme. Copyright © 2004 John Wiley & Sons, Ltd.
Discrete Rayleigh fading channel modeling
Authors: Aráuz Julio , Krishnamurthy Prashant , Labrador Miguel A.
Published: June 2004

In order to understand the behaviour of upper‐layer protocols and to design or fine tune their parameters over wireless networks, it is common to assume that the underlying channel is a flat Rayleigh fading channel. Such channels are commonly modeled as finite state Markov chains. Recently, hidden Markov models have also been employed to characterize these channels. In this paper, we study the different models that have been proposed along with the analysis of their validity. We start by presenting some preliminary concepts related to the modeling of the wireless communications channel. We then proceed to introduce finite state Markov channel models (FSMCs) along with the relations between them and the modulation schemes, error control protocols and channel coding. We propose and study the effects of taking into account the fading process in its characterization. We finish with a discussion on hidden Markov models for Rayleigh fading channel modeling. Copyright © 2004 John Wiley & Sons, Ltd.
ZCZ‐CDMA and OFDMA using M‐QAM for broadband wireless communications
Authors: Weng Jianfeng , Le‐Ngoc Tho , Xu Yinglin
Published: June 2004

This paper considers direct‐sequence code‐division multiple‐access with zero‐correlation zone sequences (ZCZ‐CDMA) and orthogonal frequency‐division multiple‐access (OFDMA) schemes using M‐ary QAM signaling for broadband wireless communications. Their system structures, complexities and performances in both AWGN and multipath frequency‐selective fading channels are evaluated and compared. For ZCZ‐CDMA, joint suppression of the multipath fading interference and multiple‐access interference can be achieved with a reduced family‐size of the spreading sequences. For OFDMA, analytical and simulation results indicate that it has the same performance as ZCZ‐CDMA in fast time‐varying multipath fading channels. In time‐invariant or slowly time‐varying channels, where the channel information can be made available to transmitters, OFDMA outperforms ZCZ‐CDMA, offers a higher capacity and is more flexible for system reconfiguration with a comparable computational complexity. Copyright © 2004 John Wiley & Sons, Ltd.
A queueing model with time‐varying QoS and call dropping for evaluating the performance of CDMA cellular systems
Authors: Liu Bin , Sule Alfa Attahiru
Published: June 2004

In this paper, we present a queueing model to evaluate the performance of CDMA reverse link in a multiple cell environment. Since CDMA capacity is interference limited, both the communication quality of ongoing calls and the admission condition of new arriving calls for each cell depend on the time‐varying signal‐to‐interference ratio (SIR). We use a quasi‐birth‐and‐death process to capture the variation of traffic loads in cells. After obtaining the stationary distribution of the system, we study some important performance indices such as the outage probability of existing calls, the blocking probability of new calls, the average carried traffic in a cell and the dropping frequency of ongoing calls. Numerical results reveal the effects of system parameters on its performance. Copyright © 2004 John Wiley & Sons, Ltd.
Channel‐estimate‐based frequency‐domain equalization (CE‐FDE) for broadband single‐carrier transmission
Authors: Zhang Qing , Le‐Ngoc Tho
Published: June 2004

A channel‐estimate‐based frequency‐domain equalization (CE‐FDE) scheme for wireless broadband single‐carrier communications over time‐varying frequency‐selective fading channels is proposed. Adaptive updating of the FDE coefficients are based on the timely estimate of channel impulse response (CIR) to avoid error propagation that is a major source of performance degradation in adaptive equalizers using least mean square (LMS) or recursive least square (RLS) algorithms. Various time‐domain and frequency‐domain techniques for initial channel estimation and adaptive updating are discussed and evaluated in terms of performance and complexity. Performance of uncoded and coded systems using the proposed CE‐FDE with diversity combining in different time‐varying, multi‐path fading channels is evaluated. Analytical and simulation results show the good performance of the proposed scheme suitable for broadband wireless communications. For channels with high‐Doppler frequency, diversity combining substantially improves the system performance. For channels with sparse multi‐path propagation, a tap‐selection strategy used with the CE‐FDE systems can significantly reduce the complexity without sacrificing the performance. Copyright © 2004 John Wiley & Sons, Ltd.
Is mechano‐sensitive expression of twist involved In mesoderm formation?
Authors: Brouzés Eric , Supatto Willy , Farge Emmanuel
Published: June 2004

Summry— Mesoderm invagination, the first morphogenetic movement of gastrulation in the early Drososphila embryo, is controlled by the expression of the twist and snail genes. Our knowledge concerning epistatic relationships between these genes implies the existence of a poorly understood biochemical maintenance of twist expression during mesoderm invagination by the snail gene. In the light of a review detailing the role of these genes in the cell shape changes leading to invagination, and of recent findings showing the expression of twist as mechanically sensitive, we suggest that the expression of twist in the mesoderm could alternatively be maintained by mechanical strains developed during mesoderm invagination.
Catecholamines restore myocardial contractility in dilated cardiomyopathy at the expense of increased coronary blood flow and myocardial oxygen consumption (MvO2 cost of catecholamines in heart failure)
Authors: Nikolaidis Lazaros A. , Trumble Dennis , Hentosz Teresa , Doverspike Aaron , Huerbin Rhonda , Mathier Michael A. , Shen You‐Tang , Shannon Richard P.
Published: June 2004

To investigate the metabolic cost of catecholamine use in heart failure, we administered intravenous dobutamine or norepinephrine to dogs with moderate and severe LV dysfunction until LV contractile function was restored to normal levels. Both drugs were associated with significant increases in myocardial O2 consumption, increased coronary blood flow requirements and decreased myocardial mechanical efficiency. These mechanisms may contribute to the deleterious effects of catecholamines in heart failure.
Echocardiographic indices of left ventricular diastolic dysfunction in 647 individuals with preserved left ventricular systolic function
Authors: Pedersen Frants , Raymond Ilan , Madsen Lene H. , Mehlsen Jesper , Atar Dan , Hildebrandt Per
Published: June 2004

Background:

Knowledge about the occurrence of isolated diastolic dysfunction (DD) in the general population is limited.

Aims:

This population study was performed to assess the frequency and distribution pattern of echocardiographic indices of left ventricular (LV) DD in an elderly population aged 50–89 years in which LV systolic function is preserved.

Methods and results:

The study population (n=764) recruited from the background population answered a heart failure questionnaire and underwent echocardiography. Excluding subjects with a LV ejection fraction <50% or atrial fibrillation, diastolic function was evaluated in 647 subjects. The frequency of impaired relaxation according to earlier guidelines was 0.5%, vs. 2.5% using age‐ and gender‐specific normal values of ‘E/A‐ratio’ and ‘deceleration time’. In a subpopulation of 167 participants, 6.6% had ‘pseudonormalisation’. No difference was found in the frequency of dyspnea in subjects with impaired relaxation or ‘pseudonormalisation’ compared to subjects with normal filling pattern.

Conclusion:

The prevalence of LV impaired relaxation was highly dependent on the choice of normal (cut‐off) values for Doppler indices. Furthermore, our findings suggest that either isolated DD is often asymptomatic, or that Doppler flow derived parameters as a diagnostic method for assessing DD have a low specificity when used as a screening tool in the general population.
Tolerability of carvedilol and ACE‐Inhibition in mild heart failure. Results of CARMEN (Carvedilol ACE‐Inhibitor Remodelling Mild CHF EvaluatioN)
Authors: Komajda Michel , Lutiger Beatrix , Madeira Hugo , Thygesen Kristian , Bobbio Marco , Hildebrandt Per , Jaarsma Wybren , Riegger Günter , Rydén Lars , Scherhag Armin , Soler‐Soler Jordi , Remme Willem J. ,   On behalf of the CARMEN investigators and co‐ordinators
Published: June 2004

Background:

Management guidelines for heart failure recommend ACE‐I and β‐blockers. The perception of difficult up‐titration might have added to the slow uptake of β‐blockers despite their mortality and morbidity benefits.

Aims:

CARMEN offered a possibility to study safety and tolerability of enalapril against carvedilol and their combination.

Methods:

Five hundred and seventy‐two patients were blindly up‐titrated on carvedilol (target 25 mg bid) and/or enalapril (target 10 mg bid), and continued for 18 months. In the combination arm, carvedilol was up‐titrated before enalapril.

Results:

There was no group related difference in adverse events during up‐titration. Withdrawal rates were 31, 30 and 30%, and serious adverse events 28, 29 and 34% in the combination, carvedilol and enalapril arms. Mortality was similar in all groups (all‐cause N=14, 14 and 14; cardiovascular N=9, 13 and 14). All‐cause and cardiovascular hospitalizations occurred in 26, 27 and 32%, and in 12, 16 and 22% in the combination, carvedilol and enalapril arms, respectively.

Conclusion:

The safety profile was similar in all treatment arms. In contrast to common perception, there was no difference in tolerability between the ACE‐I and carvedilol. This result is even more remarkable as the high prestudy use of ACE‐I (65%) might have introduced a bias by selecting ACE‐I tolerant patients, who were only switched from their former ACE‐I to enalapril.
Studies on intragastric PCO2 at rest and during exercise as a marker of intestinal perfusion in patients with chronic heart failure
Authors: Krack Andreas , Richartz Barbara M. , Gastmann Anja , Greim Kasia , Lotze Ulrich , Anker Stefan D. , Figulla Hans R.
Published: June 2004

Aims:

The aim of this study was to investigate mesenteric ischaemia by determining intragastric PCO2 (iPCO2) with gastric tonometry during rest and exercise stress testing in patients with chronic heart failure (CHF). In CHF inflammatory immune activation is hypothesized to result from a chronic endotoxin challenge due to bacterial translocation of hypoperfused intestinal mucosa.

Methods and Results:

In 10 patients with CHF and ten healthy controls a tonometry catheter was inserted into the stomach. IPCO2 was measured at rest and during bicycle exercise every 5 min. At rest arterial pCO2 (aPCO2), intragastric pCO2 (iPCO2) and the intragastric/arterial gap did not differ between patients and controls. During low level exercise (25 W), patients showed an increase in iPCO2 compared to resting iPCO2, whereas controls did not show an increase in iPCO2 (change in iPCO2: 12±2% vs. 1±0.4%, P<0.001). In CHF, iPCO2 during peak exercise was 25±3% higher than at rest, compared to controls (increase 2±1, P<0.0001).

Conclusions:

Patients with CHF already at low level exercise develop an increase in iPCO2. This is likely to reflect hypoperfusion of the intestinal mucosa, which may contribute to the development of bacterial translocation.
Clinical characteristics and treatment response in poor and good insight obsessive–compulsive disorder
Authors: Ravi Kishore V. , Samar R. , Janardhan Reddy Y.C. , Chandrasekhar C.R. , Thennarasu K.
Published: June 2004

The DSM-IV criteria recognize the existence of obsessive–compulsive disorder (OCD) with poor insight. However, there is paucity of literature on the clinical correlates and treatment response in poor and good insight OCD. In this study, insight is measured by using the Brown Assessment of Beliefs Scale (BABS) developed specifically to assess insight. One hundred subjects with DSM-IV OCD were ascertained from the OCD clinic of a large psychiatric hospital in India. All subjects were evaluated extensively by using structured instruments and established measures of psychopathology. The subjects were treated with adequate doses of drugs for adequate period. The results showed that 25% of the subjects had poor insight. Poor insight was associated with earlier age-at-onset, longer duration of illness, more number of obsessive–compulsive symptoms, more severe illness and higher comorbidity rate, particularly major depression. Of the subjects who were treated adequately (N = 73), 44 (60%) were treatment responders. Poor insight was associated with poor response to drug treatment. In the step-wise logistic regression analysis, baseline BABS score was highly predictive of poor treatment response. Poor insight appears to be associated with specific clinical correlates and poor response to drug treatment. Further studies are needed in larger samples to replicate our findings.
A protein carboxylate coordinated oxo‐centered tri‐nuclear iron complex with possible implications for ferritin mineralization
Authors: Högbom Martin , Nordlund Pär
Published: June 2004

The crystal structure of an oxo‐centered tri‐nuclear iron complex formed on a protein surface is presented. The cluster forms when crystals of the class Ib ribonucleotide reductase R2 protein from Corynebacterium ammoniagenes are subjected to iron soaking. The tri‐iron‐oxo complex is coordinated by protein‐derived carboxylate ligands arranged in a motif similar to the one found on the inner surface of ferritins and may mimic an early stage in the mineralization of iron in ferritins. In addition, the structure adds to the very limited data on protein–mineral interfaces.
Estrogen receptor activation at serine 305 is sufficient to upregulate cyclin D1 in breast cancer cells
Authors: Balasenthil Seetharaman , Barnes Christopher J. , Rayala Suresh K. , Kumar Rakesh
Published: June 2004

Recent studies have shown that p21‐activated kinase 1 (Pak1) phosphorylates estrogen receptor‐α (ERα) at Ser 305 and also promotes its transactivation function. Here, we sought to investigate whether substitution of serine 305 in ER with glutamic acid (ERα‐S305E), which mimics the phosphorylation state, would influence the status of ER‐target genes. To explore this possibility, we generated clones overexpressing ERα‐S305E in ER‐negative MDA‐MB‐231 cells and analyzed the status of ER‐regulated genes using a gene array. Results indicated that the expression of ERα‐S305E is sufficient to upregulate the expression of a few but not all ER‐regulated genes, i.e., cyclin D1 and zinc finger protein 147 (estrogen‐responsive finger protein), while there was no significant change in the expression of remaining genes on the array. In addition, we found an increased expression as well as nuclear accumulation of cyclin D1 protein in MDA‐MB‐231 cells expressing ERα‐S305E as compared to the level of cyclin D1 in MDA‐MB‐231 cells expressing WT‐ERα or pcDNA. Furthermore, ERα‐S305E, but not mutation of ERα‐S305 to alanine, enhanced the cyclin D1 promoter activity. These findings suggest that ERα activation at S305 is sufficient to upregulate the expression of cyclin D1, an ER‐regulated gene that is implicated in the progression of breast cancer. Phosphorylation of ERα by Pak1 or its upstream regulators could upregulate the expression of a subset of ER‐target genes in a ligand‐independent manner and hence, might contribute toward the development of hormone independence in breast cancer cells.
Direct fluorometric measurement of hepatitis C virus helicase activity
Authors: Boguszewska-Chachulska Anna M. , Krawczyk Mariusz , Stankiewicz Anna , Gozdek Agnieszka , Haenni Anne-Lise , Strokovskaya Ludmila
Published: June 2004

The non‐structural protein 3 (NS3) of hepatitis C virus (HCV) is a highly promising target for anti‐HCV therapy because of its multiple enzymatic activities, such as RNA‐stimulated nucleoside triphosphatase, RNA helicase and serine protease. The helicase domain of NS3 as well as domain 2 of the helicase were expressed in a baculovirus system to obtain in high yield active proteins for prospective studies of complexes of the helicase with its inhibitors. A novel direct fluorometric test of helicase activity with a quenched DNA substrate, 3′ labeled with a Cy3 dye and 5′ labeled with a Black Hole Quencher, was developed and optimal reaction conditions established. This test based on fluorescence resonance energy transfer is simple and fast. It allows for direct measurements of enzyme activity, circumventing laborious and complicated radioactive techniques that are poorly reproducible. The results obtained encourage us to propose this new fluorescent assay as a method enabling high throughput screening of anti‐helicase compounds.
NMR solution structure and position of transportan in neutral phospholipid bicelles
Authors: Bárány-Wallje Elsa , Andersson August , Gräslund Astrid , Mäler Lena
Published: June 2004

Transportan is a chimeric cell‐penetrating peptide constructed from the peptides galanin and mastoparan, which has the ability to internalize living cells carrying a hydrophilic load. In this study, we have determined the NMR solution structure and investigated the position of transportan in neutral bicelles. The structure revealed a well‐defined α‐helix in the C‐terminal mastoparan part of the peptide and a weaker tendency to form an α‐helix in the N‐terminal domain. The position of the peptide in relation to the membrane, as studied by adding paramagnetic probes, shows that the peptide lies parallel to, and in the head‐group region of the membrane surface. This result is supported by amide proton secondary chemical shifts.
Kinetic study of the H103A mutant yeast transketolase
Authors: Selivanov Vitaliy A. , Kovina Marina V. , Kochevova Natalia V. , Meshalkina Ludmilla E. , Kochetov German A.
Published: June 2004

Data from site‐directed mutagenesis and X‐ray crystallography show that His103 of holotransketolase (holoTK) does not come into contact with thiamin diphosphate (ThDP) but stabilizes the transketolase (TK) reaction intermediate, α,β‐dihydroxyethyl‐thiamin diphosphate, by forming a hydrogen bond with the oxygen of its β‐hydroxyethyl group [Eur. J. Biochem. 233 (1995) 750; Proc. Natl. Acad. Sci. USA 99 (2002) 591]. We studied the influence of His103 mutation on ThDP‐binding and enzymatic activity. It was found that mutation does not affect the affinity of the coenzyme to apotransketolase (apoTK) in the presence of Ca2+ (a cation found in the native holoenzyme) but changes all the kinetic parameters of the ThDP–apoTK interaction in the presence of Mg2+ (a cation commonly used in ThDP‐dependent enzymes studies). It was concluded that the structures of TK active centers formed in the presence of Mg2+ and Ca2+ are not identical. Mutation of His103 led to a significant acceleration of the one‐substrate reaction but a slow down of the two‐substrate reaction so that the rates of both types of catalysis became equal. Our results provide evidence for the intermediate‐stabilizing function of His103.
On the ‘Handel-ing’ of 1 Maccabees: Thomas Morell's use of biblical sources in the libretto of Judas Maccabaeus
Authors: Rooke Deborah
Published: June 2004

The Handelian oratorio Judas Maccabaeus was produced in 1746 as a compliment to the Duke of Cumberland for suppressing the Jacobite rebellion. The librettist, Thomas Morell, based his text largely on 1 Maccabees, but whereas he followed the biblical text relatively closely in Parts II and III of the libretto, he diverged from it significantly in Part I. The divergences correspond to ideas that Morell outlined in a sermon in 1739/40, which shows victory in war as inextricably linked with divine favour. Hence, Morell's version of 1 Maccabees portrays the Maccabaean campaign, and therefore the anti-Jacobite campaign which it represents, as having unequivocal divine favour.
The theology of music in church
Authors: Graham Gordan
Published: June 2004

This paper is concerned with how we should understand the distinctive contribution of music to Christian worship. It considers two contrasting views that have powerfully influenced contemporary church music – the pursuit of musical excellence by highly competent performers on the one hand, and the adoption of simpler, popular and more inclusive musical forms on the other. This contrast is explored against the background of a biblical understanding of prayer and sacrifice, and in the light of some philosophical issues surrounding both the idea of divine service and the nature of music.
Resurrection, ascension and the developing portrait of the God of Israel in Acts
Authors: Johnson Andy
Published: June 2004

This article exemplifies a theological hermeneutic where the concerns of systematic theology shape the way a NT text is read. It intends to show that the unfolding testimony of Acts 1–2 (1) continues the process begun in Luke 24 of moving its audience towardan incipiently triune portrait of Yahweh; (2) provides public testimony to the truth of God's lordship by narrating its embodiment in a restored Israel; (3) enlarges a trinitarian reader's imagination with regard to the nature of the triune life of God when that imagination is stimulated by Luke's portrait of the embodied risen and ascended Son.
The daybreak of the new creation: Christ's resurrection in recent theology
Authors: Hunsinger George
Published: June 2004

The essay suggests that three main approaches have been taken toward Christ's resurrection in recent theology. One view focuses on the question of existential meaningfulness. While it may or may not affirm the resurrection as a statement about Jesus' particular eternal destiny, it takes his resurrection primarily as a symbol of spiritual regeneration. A second view affirms precisely what the first rejects, namely, that Christ's resurrection is grounded in an actual historical occurrence. Knowledge of his resurrection is mediated by modern critical research and confirmed by it. Whether this mediation is necessary under the conditions of modernity or merely a matter of apologetic ground-clearing remains various within the type. Finally, there are those who argue that questions of meaningfulness and historicity, though important, are secondary, because determined by the nature of the resurrection event – which is necessarily unique in kind. Its meaningfulness and historicity are themselves correspondingly unique. Whereas the first type is seen as emphasizing transcendence at the expense of historicity, the second does the reverse by elevating historicity at the expense of transcendence. The mysterious conjunction of historicity and transcendence is what the third type regards as essential to understanding other relevant questions. The first type is represented by Schleiermacher, Bultmann and Tillich; the second by Pannenberg and Wright; the third by Moltmann, Frei and Barth.
A systematic theological theory of truth in Kathryn Tanner's Jesus, Humanity and the Trinity: A Brief Systematic Theology
Authors: Helmer Christine
Published: June 2004

This paper raises the truth question to explore the possibility of constructing a system of systematic theology in the contemporary context. By using Schleiermacher's thought as a constructive resource, two dimensions of truth are discussed in dialogue with Kathryn Tanner's book Jesus, Humanity and the Trinity: A Brief Systematic Theology: coherence and correspondence. Addressed in the first section is coherence, along with its auxiliary, comprehensiveness, as a requirement for system. The whole of the Christian world view is grasped by a principle of coherence that reflects both a subjective component of authorial individuality and an objective component of an individual grasp of the ‘spirit of the age’. Furthermore, consensus regarding systematic coherence in Western Christian thought agrees on a metanarrative structuring doctrines from creation to apocalypse. In Tanner's work, the principle of coherence is gift-giving that is traced from an inner-trinitarian narrative to its outer-trinitarian expressions in creation, the incarnation, eschatology, as well as in ethical response. Thematized in the second section is the tricky issue of theological correspondence between claims of redemption on the one hand and the sin, evil, and tragedy of the world on the other. Tanner's book offers one solution to this problem: analogical correspondence that situates doctrinal patterns of gift-giving (such as the incarnation, creation) as concentric circles in varying degrees of correspondence to their inner-trinitarian center. In view of this solution, this paper questions the relation between systematic coherence and the reality of both life's brokenness and the depths of divine self-giving pathos.
Ecclesiological reflections on Kathryn Tanner's Jesus, Humanity and the Trinity
Authors: Pauw Amy Plantinga
Published: June 2004

This review explores the incipient ecclesiology of Kathryn Tanner's brief systematic theology, Jesus, Humanity and the Trinity. Gift is the central concept around which Tanner's articulation of the divine life and the incarnation revolves. The lack of ecclesial definition in Jesus, Humanity and the Trinity creates tension between Tanner's theology of gift and her insistence elsewhere on the church as a ‘genuine community of argument’. Her brief appeal to a ‘community of mutual fulfillment’ needs more elaboration to head off worrisome interpretations of her vision of divine and human economies. An ecclesiological extrapolation from Tanner's Christology in Jesus, Humanity and the Trinity suggests that the church needs to be at once a community in which God's gifts are received and shared and a community of argument in which problems and shortcomings in the church's life can be faced and negotiated.
The church and action for the world: a response to Amy Pauw
Authors: Tanner Kathryn
Published: June 2004

I am very grateful to Amy Pauw for the careful and forceful way in which she has applied her considerable theological acumen, and the fruits of her long engagement with the church, to an interpretation and cautionary commentary on my book. Her remarks are a gift to me even as they chasten and redirect my efforts to expand the arguments of this book into a larger one. As I mention in an aside at the end of Chapter 3, the give and take of intellectual life, at its best, is an intimation of the community of mutual fulfillment which I believe the gospel calls us to realize everywhere. In writing the book I could only hope that faults in my arguments would be remedied and their good points developed, beyond anything I could achieve alone, by fine theologians such as Pauw taking up those arguments and offering them back to me transformed. This very exchange reflects the way a community of mutual fulfillment need not be community at a remove from disagreement, conflict, and the temptation to hubris among fallible, morally weak individuals (such as myself). In a fallen world of finite creatures, a community of mutual fulfillment often just is in this way a community of argument (of the sort I discuss in Theories of Culture) – a community that is agonistic, prone to deep disagreement about matters of shared concern, but a community held together nonetheless by the shared admission of fault and the consequent recognition that the true and the good can be had by anyone only through open engagement with all.
Knowledge, meaning, and the world's great challenges
Authors: Ford David F.
Published: June 2004

The future of Cambridge University is discussed in the context of the current British and global situation of universities, the main focus being on what the core concerns of a major university should be at this time. After raising issues related to core intellectual values (truth-seeking, rationality in argument, balanced judgement, integrity, linguistic precision and critical questioning) and the sustaining of a long-term social and intellectual ecology, four main challenges are identified: uniting teaching and research fruitfully; interrelating fields of knowledge appropriately across a wide range of disciplines; contributing to society in ways that are responsible towards the long-term flourishing of our world; and sustaining and reinventing collegiality so that the university can be a place where intensive, disciplined conversations within and across generations can flourish. The latter leads into questions of polity, governance and management. Finally, the inseparability of teaching, research and knowledge from questions of meaning, value, ethics, collegiality and transgenerational responsibility leads to proposing ‘wisdom’ as an integrating concept. The relevant sources of wisdom available are both religious and secular, and in a world that is complexly both religious and secular we need universities that can be places where both are done justice. Given the seriousness and long-term nature of the conflicts associated with religious and secular forces in our world, it is especially desirable that universities in their education of future generations contribute to the healing of such divisions.
Beyond Shamanism: Landscape and Self-Expression in the Petroglyphs of Inner Mongolia and Ningxia (China)
Authors: Demattè Paola
Published: June 2004

Petroglyph sites in the Yinshan and Helanshan ranges were documented during a recent survey. Archaeological remains indicate that these areas have for millennia been both militarized borders and osmotic trading zones connecting the pastoral people of northern Asia and the Chinese world. Petroglyphs form a significant part of the material and symbolic culture of this transitional zone from the Neolithic down to the later dynastic phases (nineteenth century). By using newly-gathered data, this article moves away from interpretations which see rock art as a wholly shamanistic phenomenon, introducing territory and iconography as key elements for the understanding of local geographies, cultural interactions, and the agencies of identity. The location of the sites indicates that petroglyphs were next to travel routes and may have served as territory markers and meeting places. In addition, the scattering of marked rocks in key locations suggests that petroglyphs were markers of identity essential for a people who were engaged in a dialectic contention with the expanding agricultural world. The sense of identity can be perceived also in the subject matter (wild and domesticated animals, hunting and herding scenes, faces) which seems to emphasize respect for, or even enjoyment of, pastoral and nomadic life.
Review Feature: A review of Genesis of the Pharaohs: Dramatic New Discoveries that Rewrite the Origins of Ancient Egypt, by Toby Wilkinson. London: Thames & Hudson, 2002. ISBN 0-500-05122-4 hardback £18.95; 208 pp., 87 ills., 25 in colour
Authors: Wilkinson Toby , Butzer Karl W. , Huyge Dirk , Hendrickx Stan , Kendall Timothy , Shaw Ian
Published: June 2004

The processes leading to the formation of early state societies remain one of the key topics of archaeological research. Few of these early states are as famous or evocative as that of ancient Egypt, a land of dramatic monuments and terrain, with mysterious and exotic religious practices and a distinctive and exotic iconography. But was Egypt the gift of the Nile, as the Greek historian Herodotus alleged? In this new book, Toby Wilkinson draws attention to a relatively neglected part of the Egyptian landscape: not the fertile river valley, but the deserts which fringe it to east and west. It is here in the deserts, he argues, that the origins of the Egyptian state are to be found. In recent millennia, the deserts have been hostile environments of rock and sand. Go back before 3000 bc, however, and a rather different picture emerges. This different picture is of a desert hinterland peopled by nomadic groups who spent part of their year in the Nile valley. It suggests a more mobile view of Egyptian Predynastic society than has usually been supposed. Desert and valley may have functioned together in a classic pattern of complementarity between contrasting environmental zones, with cattle herds perhaps moved from valley floor to desert in step with the cyclical pattern of the seasons. The specific ingredient which Wilkinson uses to link valley and desert during the fourth millennium bc is rock art. Egyptian rock art has not yet been properly recognized as a rich and important repertoire by specialists in the burgeoning field of rock art as whole. Surveys over more than a century, however, have revealed numerous groups of pecked and engraved images on the desert cliffs and boulders, and recent expeditions (including those by Wilkinson himself) are continually adding to the corpus. The Egyptian desert rock art is generally less well-known than the vivid rock paintings of the central Sahara (such as the famous Tassili frescoes), though it too conveys the image of a greener more habitable landscape. Wilkinson ties specific motifs found in the desert rock art to iconography from the Nile valley during the fourth millennium and later. Yet the linkages and chronologies remain controversial, along with the central hypothesis. Did the desiccation of the savannas lead to the formation of the Egypt, forcing the scattered pastoralist populations to withdraw to a cultivated Nile valley? Was Egypt the gift of the deserts, not the Nile? In this Review Feature the hypothesis is examined by specialists working in Egypt and Nubia, and the reliability of the supporting evidence is assessed.
Modeling the distribution of Trichodesmium and nitrogen fixation in the Atlantic Ocean
Authors: Hood Raleigh R. , Coles Victoria J. , Capone Douglas G.
Published: June 2004

In this paper we use a coupled, 3‐dimensional, biological‐physical model, which includes an explicit, dynamic representation of Trichodesmium, to predict the distribution of Trichodesmium and rates of N2‐fixation in the tropical and subtropical Atlantic Ocean. It is shown that the model reproduces the approximate observed meridional distribution of Trichodesmium in the Atlantic and elevated concentrations in specific coastal and open ocean regions where this organism is known to occur. The model also appears to reproduce the observed seasonality of Trichodesmium populations at higher latitudes (highest concentrations in summer and fall), but this seasonal cycle may be too pronounced at low latitudes. High and persistent Trichodesmium concentrations and rates of N2‐fixation are generated by the model in the Gulf of Guinea off of Africa. This unexpected finding appears to be confirmed by historical measurements. In general, increased Trichodesmium concentrations develop in regions where the mixed layer is relatively thin (resulting in high mean light levels) and dissolved inorganic nitrogen (DIN) concentrations and phytoplankton biomass are low for extended periods of time. The model‐predicted Trichodesmium distributions are therefore very sensitive to the fidelity of the physical model's representation of mixed layer depth variability, and upwelling intensity, and the biological model's estimated DIN and phytoplankton concentrations. The model generates a three‐step successional sequence where (1) high DIN concentrations due to upwelling and/or mixing stimulate phytoplankton growth, followed by (2) Trichodesmium growth after DIN depletion and phytoplankton decline, followed by (3) enhanced phytoplankton growth due to new nitrogen inputs from N2‐fixation. This sequence develops in response to seasonal variations in mixing in the southwestern North Atlantic and in response to upwelling along the coast of Africa and the equator. We interpret this sequence as representing a diatom‐ Trichodesmium‐flagellate succession, which is consistent with observed species successions off of northwest Africa and in the Gulf of Mexico. The results presented in this paper lead us to conclude that our model includes the primary factors that dictate when and where Trichodesmium and N2‐fixation occurs in the Atlantic. Moreover, it appears that our model reproduces some of the major effects that diazotrophically‐derived inputs of new nitrogen have on the pelagic ecosystem.