bluuebunny/crossref_metadata_2025 huggingface dataset:
Ketamine Improves the Management of Exaggerated Postoperative Pain Observed in Perioperative Fentanyl-treated Rats
Authors: Richebé Philippe , Rivat Cyril , Laulin Jean-Paul , Maurette Pierre , Simonnet Guy
Published: January 2005

Background

Although opioids are unsurpassed analgesics, experimental and clinical studies suggest that opioids activate N-methyl-d-aspartate pronociceptive systems leading to pain hypersensitivity and short-term tolerance. Because it is difficult in humans to differentiate pain from hyperalgesia during the postoperative period, the authors performed experimental studies with fentanyl using the rat incisional pain model for evaluating relations between hyperalgesia and short-term tolerance. Because N-methyl-d-aspartate receptor antagonists oppose both pain hypersensitivity and tolerance induced by opioids, the authors examined the capability of ketamine for improving exaggerated postoperative pain management.

Methods

During halothane anesthesia, a hind paw plantar incision was performed in rats receiving four fentanyl subcutaneous injections (100 microg/kg per injection, every 15 min). In some groups, three subcutaneous ketamine injections (10 mg/kg per injection, every 5 h) were performed in saline- or fentanyl-treated rats. One day after surgery, the analgesic effect of morphine (2 mg/kg subcutaneous) was tested. Analgesia, mechanical hyperalgesia, tactile allodynia, and pain score were assessed for several days using the paw pressure vocalization test, the von Frey application test, and the postural disequilibrium test.

Results

Fentanyl induced analgesia but also produced exaggerated postoperative pain as indicated by the enhancement of hyperalgesia, allodynia, and weight-bearing decrease after hind paw plantar incision. Ketamine pretreatment prevented such a fentanyl-induced enhancement of postoperative pain and improved its management by morphine.

Conclusions

By opposing postoperative pain hypersensitivity and subsequent short-term tolerance induced by perioperative opioid use, ketamine not only improves exaggerated postoperative pain management but also provides better postoperative rehabilitation.
Genetic Modulation of Adrenergic Activity in the Heart and Vasculature: Implications for Perioperative Medicine
Authors: Zaugg Michael , Schaub Marcus C. , Warltier David C.
Published: January 2005

The adrenergic system provides the primary control for cardiac, vascular, pulmonal, and metabolic functions. Seven of the nine adrenergic receptor subtypes display mutations that affect their function. Results from transgenic mouse models and from association studies in human populations allow to link protein dysfunctions to cardiovascular diseases or to risk for disease development. The disease contribution by single nucleotide polymorphisms may be small. Series of single nucleotide polymorphisms along a chromosome are combined in haplotypes and inherited together. Individual single nucleotide polymorphisms in a haplotype can influence each other and lead to new, unpredictable phenotypes. Haplotypes vary widely among different ethnic groups. In this review, we discuss the genetic organization of single nucleotide polymorphisms and haplotypes in the adrenergic system and their implications for the heart and vasculature with special reference to perioperative medicine. With the advent of powerful genomic technologies, genotyping may become standard in patient evaluation and will help to individualize therapeutic approaches.
Voluntarily controlled bi–stable slant perception of real and photographed surfaces
Authors: van Ee Raymond , Krumina Gunta , Pont Sylvia , van der Ven Sanne
Published: January 2005

We have quantified voluntarily selected perceived slant of real trapezoidal surfaces (a ‘reverse–perspective’ scene) and their photographed counterparts (pictorial space). The surfaces were slanted about the vertical axis and observers estimated slant relative to the frontal plane. We were particularly interested in those cases in which binocular disparity and monocular perspective provided conflicting slant information. We varied the monocularly and binocularly specified surface slants independently across stimulus presentations. To eliminate texture and shading cues we used sand–blasted aluminium trapezoidal surfaces illuminated from all directions. When disparity–specified slant and perspective–specified slant were conflicting, observers were able to perceive the surfaces in two ways: they perceived either a trapezoid or a rectangle. Our main finding is twofold. First, when subjects chose to perceive the trapezoid, the slant estimates followed the disparity–predicted slant with only a slight underestimation, as if they selected a pure binocular representation of slant governed only by disparity. Second, when subjects chose to perceive the rectangle their estimates for real surfaces were similar to those for photographed surfaces, as if they selected a representation of slant governed by perspective foreshortening.
The landscape context of cereal aphid–parasitoid interactions
Authors: Thies Carsten , Roschewitz Indra , Tscharntke Teja
Published: January 2005

Analyses at multiple spatial scales may show how important ecosystem services such as biological control are determined by processes acting on the landscape scale. We examined cereal aphid–parasitoid interactions in wheat fields in agricultural landscapes differing in structural complexity (32–100% arable land). Complex landscapes were associated with increased aphid mortality resulting from parasitism, but also with higher aphid colonization, thereby counterbalancing possible biological control by parasitoids and lastly resulting in similar aphid densities across landscapes. Thus, undisturbed perennial habitats appeared to enhance both pests and natural enemies. Analyses at multiple spatial scales (landscape sectors of 0.5–6 km diameter) showed that correlations between parasitism and percentage of arable land were significant at scales of 0.5–2 km, whereas aphid densities responded to percentage of arable land at scales of 1–6 km diameter. Hence, the higher trophic level populations appeared to be determined by smaller landscape sectors owing to dispersal limitation, showing the ‘functional spatial scale’ for species–specific landscape management.
Life–history variation and allometry for sexual size dimorphism in Pacific salmon and trout
Authors: Young Kyle A.
Published: January 2005

Allometry for sexual size dimorphism (SSD) is common in animals, but how different evolutionary processes interact to determine allometry remains unclear. Among related species SSD (male : female) typically increases with average body size, resulting in slopes of less than 1 when female size is regressed on male size: an allometric relationship formalized as ‘Rensch's rule’ . Empirical studies show that taxa with male–biased SSD are more likely to satisfy Rensch's rule and that a taxon's mean SSD is negatively correlated with allometric slope, implicating sexual selection on male size as an important mechanism promoting allometry for SSD. I use body length (and life–history) data from 628 (259) populations of seven species of anadromous Pacific salmon and trout (Oncorhynchusspp.) to show that in this genus life–history variation appears to regulate patterns of allometry both within and between species. Although all seven species have intraspecific allometric slopes of less than 1, contrary to expectation slope is unrelated to species' mean SSD, but is instead negatively correlated with two life–history variables: the species' mean marine age and variation in marine age. Second, because differences in marine age among species render SSD and body size uncorrelated, the interspecific slope is isometric. Together, these results provide an example of how evolutionary divergence in life history among related species can affect patterns of allometry for SSD across taxonomic scales.
A division of labour with role specialization in group–hunting bottlenose dolphins (
Tursiops truncatus
) off Cedar Key, Florida
Authors: Gazda Stefanie K. , Connor Richard C. , Edgar Robert K. , Cox Frank
Published: January 2005

Individual role specialization during group hunting is extremely rare in mammals. Observations on two groups of bottlenose dolphins (
Tursiops truncatus
) in Cedar Key, Florida revealed distinctive behavioural roles during group feeding. In each group, one individual was consistently the ‘driver’, herding the fishes in a circle toward the remaining ‘barrier’ dolphins. Aerial fish–capture rates differed between groups, as well as between the driver and barrier dolphins, in one group but not in the other. These differences between the two groups may reflect differences in group stability or in prey school size.
Management of genetically modified herbicide–tolerant sugar beet for spring and autumn environmental benefit
Authors: May Mike J. , Champion Gillian T. , Dewar Alan M. , Qi Aiming , Pidgeon John D.
Published: January 2005

When used in genetically modified herbicide–tolerant (GMHT) crops, glyphosate provides great flexibility to manipulate weed populations with consequences for invertebrates and higher trophic levels, for example birds. A range of timings of band and overall spray treatments of glyphosate to GMHT sugar beet were compared with a conventional weed control programme in four field trials over 2 years. Single overall sprays applied between 200 and 250 accumulated day degrees (above a base air temperature of 3°C; °Cd) and band applied treatments applied at 10% or 20% ground cover within the crop rows generally gave significantly greater weed biomass and seed rain than conventional treatments, while later band sprays (more than 650 °Cd) reduced seed return. Two overall sprays of glyphosate produced low weed biomass and generally lowest seed return of all treatments but tended to give some of the highest yields. However, the early overall sprays (200–250 °Cd) and band sprays gave as good or better yields than the conventional and were generally equivalent to the two overall–spray programme. Viable seeds in the soil after the experiment were generally higher following the early overall (200–250 °Cd) and the band spray treatments than following the conventional. The results show that altered management of GMHT sugar beet can provide alternative scenarios to those of the recent Farm Scale Evaluation trials. Without yield loss they can enhance weed seed banks and autumn bird food availability compared with conventional management, or provide early season benefits to invertebrates and nesting birds, depending on the system chosen. Conventional weed control does not have the flexibility to enable these scenarios that benefit both agriculture and environment, although there may be some options for increasing weed seed return in autumn.
Banana contains a diverse array of endogenous badnaviruses
Authors: Geering Andrew D. W. , Olszewski Neil E. , Harper Glyn , Lockhart Benham E. L. , Hull Roger , Thomas John E.
Published: January 2005

Banana streak disease is caused by several distinct badnavirus species, one of which is Banana streak Obino l'Ewai virus. Banana streak Obino l'Ewai virus has severely hindered international banana (Musa spp.) breeding programmes, as new hybrids are frequently infected with this virus, curtailing any further exploitation. This infection is thought to arise from viral DNA integrated in the nuclear genome of Musa balbisiana (B genome), one of the wild species contributing to many of the banana cultivars currently grown. In order to determine whether the DNA of other badnavirus species is integrated in the Musa genome, PCR-amplified DNA fragments from Musa acuminata, M. balbisiana and Musa schizocarpa, as well as cultivars ‘Obino l'Ewai’ and ‘Klue Tiparot’, were cloned. In total, 103 clones were sequenced and all had similarity to open reading frame III in the badnavirus genome, although there was remarkable variation, with 36 distinct sequences being recognized with less than 85 % nucleotide identity to each other. There was no commonality in the sequences amplified from M. acuminata and M. balbisiana, suggesting that integration occurred following the separation of these species. Analysis of rates of non-synonymous and synonymous substitution suggested that the integrated sequences evolved under a high degree of selective constraint as might be expected for a living badnavirus, and that each distinct sequence resulted from an independent integration event.
Following the very initial growth of biological RNA viral clones
Authors: Cuevas José M. , Moya Andrés , Sanjuán Rafael
Published: January 2005

Due to their extremely high genetic diversity, which is a direct consequence of high mutation rates, RNA viruses are often described as molecular quasispecies. According to this theory, RNA virus populations cannot be understood in terms of individual viral clones, as they are clouds of interconnected mutants, but this prediction has not yet been demonstrated experimentally. The goal of this study was to determine the fitness of individual clones sampled from a given RNA virus population, a necessary previous step to test the above prediction. To do so, limiting dilutions of a vesicular stomatitis virus population were employed to isolate single viral clones and their initial growth dynamics were followed, corresponding to the release of the first few hundred viral particles. This technique is useful for estimating basic fitness parameters, such as intracellular growth rate, viral yield per cell, rate at which cells are infected and time spent in cell-to-cell transmission. A combination of these parameters allows estimation of the fitness of individual clones, which seems to be determined mainly by their ability to complete infection cycles more quickly. Interestingly, fitness was systematically higher for initial clones than for their derived populations. In addition to environmental changes, such as cellular defence mechanisms, these differences are attributable to high RNA virus mutation rates.
Molecular characterization of the complete genome of human influenza H5N1 virus isolates from Thailand
Authors: Puthavathana Pilaipan , Auewarakul Prasert , Charoenying Pakapak Chor , Sangsiriwut Kantima , Pooruk Phisanu , Boonnak Kobporn , Khanyok Raweewan , Thawachsupa Pranee , Kijphati Rungrueng , Sawanpanyalert Pathom
Published: January 2005

The complete genomes of three human H5N1 influenza isolates were characterized, together with the haemagglutinin (HA) and neuraminidase (NA) genes from two additional human isolates and one chicken isolate. These six influenza isolates were obtained from four different provinces of Thailand during the avian influenza outbreak in Asia from late 2003 to May 2004. All six Thailand isolates contained multiple basic amino acids at the cleavage site in the HA gene. Amino acid residues at the receptor-binding site of the five human viruses were similar to those of the chicken virus and other H5N1 viruses from Hong Kong. The presence of amantadine resistance in the Thailand viruses isolated during this outbreak was suggested by a fixed mutation in M2 and confirmed by a phenotypic assay. All genomic segments of the Thailand viruses clustered with the recently described genotype Z. The Thailand viruses contained more avian-specific residues than the 1997 Hong Kong H5N1 viruses, suggesting that the virus may have adapted to allow a more efficient spread in avian species.
The human cytomegalovirus UL78 gene is highly conserved among clinical isolates, but is dispensable for replication in fibroblasts and a renal artery organ-culture system
Authors: Michel Detlef , Milotić Irena , Wagner Markus , Vaida Bianca , Holl Jens , Ansorge Ramona , Mertens Thomas
Published: January 2005

The human cytomegalovirus (HCMV) UL78 ORF is considered to encode a seven-transmembrane receptor. However, neither the gene nor the UL78 protein has been characterized so far. The objective of this study was to investigate the UL78 gene and to clarify whether it is essential for replication. UL78 transcription was activated early after infection, was inhibited by cycloheximide but not by phosphonoacetic acid, and resulted in a 1·7 kb mRNA. Later in the replication cycle, a second mRNA of 4 kb evolved, comprising the UL77 and UL78 ORFs. The 5′ end of the UL78 mRNA initiated 48 bp upstream of the translation start and the polyadenylated tail started 268 bp downstream of the UL78 translation stop codon within the UL79 ORF. By using bacterial artificial chromosome technology, a recombinant HCMV lacking most of the UL78 coding region was constructed. Successful reconstitution of the UL78-deficient virus proved that the gene was not essential for virus replication in fibroblasts. The deletion also did not reduce virus replication in ex vivo-cultured sections of human renal arteries. Analysis of viral proteins at different stages of the replication cycle confirmed these results. Among clinical HCMV isolates, the predicted UL78 protein was highly conserved. However, an accumulation of different single mutations could be found in the N-terminal region and at the very end of the C terminus. Due to the absence of an in vivo HCMV model, the role of UL78 in the pathogenesis of HCMV infection in humans remains unclear.
Back-priming mode of ϕ6 RNA-dependent RNA polymerase
Authors: Laurila Minni R. L. , Salgado Paula S. , Stuart David I. , Grimes Jonathan M. , Bamford Dennis H.
Published: January 2005

The RNA-dependent RNA polymerase of the double-stranded RNA bacteriophage ϕ6 is capable of primer-independent initiation, as are many RNA polymerases. The structure of this polymerase revealed an initiation platform, composed of a loop in the C-terminal domain (QYKW, aa 629–632), that was essential for de novo initiation. A similar element has been identified in hepatitis C virus RNA-dependent RNA polymerase. Biochemical studies have addressed the role of this platform, revealing that a mutant version can utilize a back-priming initiation mechanism, where the 3′ terminus of the template adopts a hairpin-like conformation. Here, the mechanism of back-primed initiation is studied further by biochemical and structural methods.
Reactivation of Epstein–Barr virus can be triggered by an Rta protein mutated at the nuclear localization signal
Authors: Hsu Tsuey-Ying , Chang Yao , Wang Pei-Wen , Liu Mei-Ying , Chen Mei-Ru , Chen Jen-Yang , Tsai Ching-Hwa
Published: January 2005

Rta, an immediate-early protein of Epstein–Barr virus (EBV), is a transcriptional activator that induces lytic gene expression and triggers virus reactivation. Being located predominantly in the nucleus, Rta can exert its transactivation function through either direct DNA binding or certain indirect mechanisms mediated by cellular signalling and other transcriptional factors. This study examined whether the subcellular localization of Rta was critical for the induction of target genes. First, 410KRKK413 was identified as a nuclear localization signal (NLS) of Rta. An Rta mutant with the NLS converted to 410AAAA413 showed cytoplasmic localization and failed to activate the promoter of BGLF5. Interestingly, ectopic expression of the Rta mutant still disrupted EBV latency in an epithelial cell line. Reporter gene assays revealed that the NLS-mutated Rta retained the ability to activate two lytic promoters, Zp and Rp, at a considerable level. Thus, the cytoplasmic Rta mutant could induce expression of endogenous Zta and Rta, triggering reactivation of EBV.
The respiratory syncytial virus small hydrophobic protein is phosphorylated via a mitogen-activated protein kinase p38-dependent tyrosine kinase activity during virus infection
Authors: Rixon H. W. McL. , Brown G. , Murray J. T. , Sugrue R. J.
Published: January 2005

The phosphorylation status of the small hydrophobic (SH) protein of respiratory syncytial virus (RSV) was examined in virus-infected Vero cells. The SH protein was isolated from [35S]methionine- and [33P]orthophosphate-labelled RSV-infected cells and analysed by SDS-PAGE. In each case, a protein product of the expected size for the SH protein was observed. Phosphoamino acid analysis and reactivity with the phosphotyrosine specific antibody PY20 showed that the SH protein was modified by tyrosine phosphorylation. The role of tyrosine kinase activity in SH protein phosphorylation was confirmed by the use of genistein, a broad-spectrum tyrosine kinase inhibitor, to inhibit SH protein phosphorylation. Further analysis showed that the different glycosylated forms of the SH protein were phosphorylated, as was the oligomeric form of the protein. Phosphorylation of the SH protein was specifically inhibited by the mitogen-activated protein kinase (MAPK) p38 inhibitor SB203580, suggesting that SH protein phosphorylation occurs via a MAPK p38-dependent pathway. Analysis of virus-infected cells using fluorescence microscopy showed that, although the SH protein was distributed throughout the cytoplasm, it appeared to accumulate, at low levels, in the endoplasmic reticulum/Golgi complex, confirming recent observations. However, in the presence of SB203580, an increased accumulation of the SH protein in the Golgi complex was observed, although other virus structures, such as virus filaments and inclusion bodies, remained largely unaffected. These results showed that during RSV infection, the SH protein is modified by an MAPK p38-dependent tyrosine kinase activity and that this modification influences its cellular distribution.
Genetic clustering of Borna disease virus natural animal isolates, laboratory and vaccine strains strongly reflects their regional geographical origin
Authors: Kolodziejek Jolanta , Dürrwald Ralf , Herzog Sibylle , Ehrensperger Felix , Lussy Helga , Nowotny Norbert
Published: January 2005

The aim of this study was to gain more detailed insights into the genetic evolution and variability of Borna disease virus (BDV). Phylogenetic analyses were performed on field viruses originating from naturally infected animals, the BDV vaccine strain ‘Dessau’, four widely used laboratory strains and the novel BDV subtype No/98. Four regions of the BDV genome were analysed: the complete p40, p10 and p24 genes and the 5′-untranslated region of the X/P transcript. BDV isolates from the same geographical area exhibited a clearly higher degree of identity to each other than to BDV isolates from other regions, independent of host species and year of isolation. Five different clusters could be established within endemic areas, corresponding to the geographical regions from which the viruses originated: (i) a Swiss, Austrian and Liechtenstein Rhine valley group, related closely to the geographically bordering Baden-Wurttemberg and Bavaria II group (ii) in the western part of Germany; (iii) a third group, called Bavaria I group, limited in occurrence to Bavaria; (iv) a southern Saxony-Anhalt and bordering northern Saxony group, bound to the territories of these federal states in the eastern part of Germany; and (v) a mixed group, consisting of samples from different areas of Germany; however, these were mainly from the federal states of Thuringia and Lower Saxony. The laboratory strains and the vaccine strain clustered within these groups according to their geographical origins. All field and laboratory strains, as well as the vaccine strain, clearly segregated from the recently described and highly divergent BDV strain No/98, which originated from an area in Austria where Borna disease is not endemic.
Intracellular salivation is the aphid activity associated with inoculation of non-persistently transmitted viruses
Authors: Powell Glen
Published: January 2005

Approximately 75 % of aphid-vectored viruses are transmitted in a non-persistent (non-circulative) manner. Localization studies indicate that such viruses are acquired via ingestion and retained in the food canal of the maxillary stylets, but the inoculation mechanism has remained unresolved. Electrical recording of stylet penetration activities reveals that inoculation is associated with the first intracellular activity (subphase II-1) following maxillary puncture of an epidermal cell. Subphase II-1 may represent virus inoculation via egestion (regurgitation of virions with food-canal contents) or salivation (saliva-mediated release of virions from the common food-salivary duct at the tips of the maxillary stylets). Here, inoculation of the circulatively transmitted Pea enation mosaic virus was used as a marker for intracellular salivation during epidermal cell punctures. The results confirmed that inoculation of non-persistently transmitted viruses (subphase II-1) is associated with active injection of saliva directly into the cytoplasm.
Host-directed processing of Citrus exocortis viroid
Authors: Szychowski J. A. , Vidalakis G. , Semancik J. S.
Published: January 2005

Prolonged infection of tomato hybrid (Lycopersicon esculentum×Lycopersicon peruvianum) by Citrus exocortis viroid (CEVd) resulted in viroid-like enlarged structures, detected by gel electrophoresis. This population included two new enlarged variants or D-variants, D-87 and D-76, and three transient species or D-forms, D-38, D-40 and D-43. Sequence analyses exposed a locus near the terminal repeat region where major changes appeared consistently. In transmission tests to CEVd hosts, a variety of progeny populations were recovered, including progeny enlargements of and reversions to CEVd, as well as sequence fidelity to the inoculum. Transmission tests to citrus hosts of the genera Citrus, Poncirus or Fortunella were unsuccessful. The importance of host specificity to the recovery and processing of the various CEVd-related structures, as well as the temporal variability of progeny populations, was demonstrated.
Determination of the structure of the violet pigment C22H12Cl2N6O4 from a non-indexed X-ray powder diagram
Authors: Schmidt Martin U. , Ermrich Martin , Dinnebier Robert E.
Published: January 2005

The violet pigment methylbenzimidazolonodioxazine, C22H12Cl2N6O4 (systematic name: 6,14-dichloro-3,11-dimethyl-1,3,9,11-tetrahydro-5,13-dioxa-7,15-diazadiimidazo-[4,5-b:4′,5′-m]pentacene-2,10-dione), shows an X-ray powder diagram consisting of only ca 12 broad peaks. Indexing was not possible. The structure was solved by global lattice energy minimizations. The program CRYSCA [Schmidt & Kalkhof (1999), CRYSCA. Clariant GmbH, Pigments Research, Frankfurt am Main, Germany] was used to predict the possible crystal structures in different space groups. By comparing simulated and experimental powder diagrams, the correct structure was identified among the predicted structures. Owing to the low quality of the experimental powder diagram the Rietveld refinements gave no distinctive results and it was difficult to prove the correctness of the crystal structure. Finally, the structure was confirmed to be correct by refining the crystal structure of an isostructural mixed crystal having a better X-ray powder diagram. The compound crystallizes in P\bar 1, Z = 1. The crystal structure consists of a very dense packing of molecules, which are connected by hydrogen bridges of the type N—H...O=C. This packing explains the observed insolubility. The work shows that crystal structures of molecular compounds may be solved by lattice energy minimization from diffraction data of limited quality, even when indexing is not possible.
Crystal structure study of a β′-copper vanadium bronze, Cu
x
V2O5 (x = 0.63), by X-ray and convergent beam electron diffraction
Authors: Streltsov Victor A. , Nakashima Philip N. H. , Sobolev Alexandre N. , Ozerov Ruslan P.
Published: January 2005

The single-crystal structure of a β′-copper vanadium bronze, Cu0.63V2O5, has been studied at room temperature and 9.6 K, and compared with that of the β-sodium vanadium bronze, Na0.33V2O5, structure. No convincing evidence to oppose an assignment of centrosymmetric C2/m symmetry to the structure was identified using the X-ray data. A subsequent convergent beam electron diffraction (CBED) experiment was performed and confirmed the C2/m space group. The oxygen–vanadium atom framework of Cu0.63V2O5 is close to that of Na0.33V2O5. However, in the copper compound the Cu atoms are located in two positions: Cu1 in the 4(i) position with x = 0.541, y = 0 and z = 0.345, and Cu2 in the 8(j) position with x = 0.529, y = 0.038 and z = 0.357. The crystal structure changes little with temperature. Disorder of the Cu ion over two sites is seen at 9.6 K. This suggests that distribution of the Cu atoms over two sites is of a more static than dynamic nature.
Method for the computational comparison of crystal structures
Authors: Willighagen E. L. , Wehrens R. , Verwer P. , de Gelder R. , Buydens L. M. C.
Published: January 2005

A new method for assessing the similarity of crystal structures is described. A similarity measure is important in classification and clustering problems in which the crystal structures are the source of information. Classification is particularly important for the understanding of properties of crystals, while clustering can be used as a data reduction step in polymorph prediction. The method described uses a radial distribution function that combines atomic coordinates with partial atomic charges. The descriptor is validated using experimental data from a classification study of clathrate structures of cephalosporins and data from a polymorph prediction run. In both cases, excellent results were obtained.
Formation of quinol co-crystals with hydrogen-bond acceptors
Authors: Oswald Iain D. H. , Motherwell W. D. Samuel , Parsons Simon
Published: January 2005

The crystal structures of eight new co-crystals of quinol with pyrazine, piperazine, morpholine, pyridine, piperidine, 4,4′-bipyridine, N-methylmorpholine and N,N′-dimethylpiperazine are reported. Quinol forms 1:1 co-crystals with pyrazine, piperazine and N,N′-dimethylpiperazine, but 1:2 co-crystals with morpholine, 4,4′-bipyridine, N-methylmorpholine, pyridine and piperidine. This difference can be rationalized in most cases by the presence of, respectively, two or one strong hydrogen-bond acceptor(s) in the guest molecule. The exception to this generalization is 4,4′-bipyridine, which forms a 1:2 co-crystal, possibly to optimize crystal packing. All structures are dominated by hydrogen bonding between quinol and the guest molecules. A doubly bridging motif, which connects pairs of quinol and guest molecules via NH...O or CH...O interactions, is present in all but the sterically hindered N,N′-dimethylpiperazine and N-methylmorpholine co-crystals.
Supramolecular structures of 1-phenylethylammonium tartrates
Authors: Turkington David E. , MacLean Elizabeth J. , Lough Alan J. , Ferguson George , Glidewell Christopher
Published: January 2005

The structures of six 1-phenylethylammonium tartrates have been determined and in each of them a distinctive hydrogen-bonded anion substructure can be identified. (S)-1-Phenylethylammonium (R,R)-hydrogen tartrate [(I), P21, Z′ = 1] contains anion sheets built from a single type of R_4^4(22) ring with cations pendent, via three N—H...O hydrogen bonds, from just one face of the sheet. (S)-1-Phenylethylammonium rac-hydrogen tartrate [(II), P21, Z′ = 2] and its enantiomorph (R)-1-phenylethylammonium rac-hydrogen tartrate [(III), P21, Z′= 2] contain anion sheets built from four types of ring, R_2^2(10), R_2^2(12), R^4_2(14) and R_4^4(20), and there are cations pendent from both faces of the sheet. The anion substructure in bis[(S)-1-phenylethylammonium] (R,R)-tartrate [(IV), P21, Z′ = 1] consists of simple C(5) chains, which are linked into sheets by the cations, while in bis(rac-1-phenylethylammonium) (R,R)-tartrate [(V), P21, Z′ = 2] there are anion sheets containing two distinct types of R_4^4(22) ring, with equal numbers of (R) and (S) cations pendent from each face of the anion sheet. Bis[(R)-1-phenylethylammonium] rac-tartrate methanol hemisolvate [(VI), P1, Z′ = 4, with 14 independent components in the asymmetric unit] contains anion sheets built from two types of R_2^2(12) ring and two types of R_6^6(32) ring; half of the cations and half of the methanol molecules are pendent from each face of the sheet.
X-ray studies on crystalline complexes involving amino acids and peptides. XLII. Adipic acid complexes of L- and DL-arginine and supramolecular association in arginine–dicarboxylic acid complexes
Authors: Roy Siddhartha , Singh Desh Deepak , Vijayan M.
Published: January 2005

The adipic acid complexes of DL-arginine and L-arginine are made up of zwitterionic, singularly positively charged arginium ions and doubly negatively charged adipate ions, with a 2:1 stoichiometry. One of the two crystallographically independent arginium ions in the L-arginine complex has a conformation hitherto unobserved in crystal structures containing the amino acid. In the present study the structural data on arginine complexes of saturated dicarboxylic acids with 0–5 C atoms separating the two carboxyl functions are given. In terms of molecular aggregation, formic and acetic acid complexes behave in a similar way to those involving fairly long carboxylic acids such as adipic acid. By and large, the supramolecular assembly in complexes involving dicarboxylic acids with 3 or more C atoms separating the carboxyl groups (glutaric, adipic and pimelic acids), and those involving formic and acetic acids, have common features. The aggregation patterns in complexes involving oxalic, malonic and maleic acids do not share striking features among themselves (except for the mode of hydrogen-bonded dimerization of arginium ions) or with those involving larger dicarboxylic acids. Complexes of succinic acid, the shortest linear dicarboxylic acid, share features with those involving shorter as well as longer dicarboxylic acids. The difference in the behaviour of long and short dicarboxylic acids and the ambiguous behaviour of succinic acid can be broadly related to their lengths.
Structure determination of forms I and II of phenobarbital from X-ray powder diffraction
Authors: Platteau Cyril , Lefebvre Jacques , Hemon Stephanie , Baehtz Carsten , Danede Florence , Prevost Dominique
Published: January 2005

From pure powders of forms I and II of phenobarbital, X-ray diffraction patterns were recorded at room temperature. The starting crystal structural models were found by a Monte-Carlo simulated annealing method. The structures of the two forms were obtained through Rietveld refinements. Soft restraints were applied on bond lengths and bond angles, all H-atom positions were calculated. The cell of form I is monoclinic with the space group P21/n, Z = 12, Z′ = 3. Form II has a triclinic cell, with the space group P\bar 1, Z = 6, Z′ = 3. For both forms, the crystal cohesion is achieved by networks of N—H...O hydrogen bonds along [101]. The broadening of the Bragg peak profiles is interpreted in terms of isotropic strain effects and anisotropic size effects.
Rural‐urban and regional inequality in output, income and consumption in China under economic reforms
Authors: Yao Shujie , Zhang Zongyi , Feng Gengfu
Published: January 2005

Purpose

Fast growth in China has led to significant improvement in people's living standards and average income. However, it has also brought about a huge rise in inequality. The purpose of this paper is to analyse regional and rural‐urban inequality using a few income and consumption indicators.

Design/methodology/approach

Data are collected from official statistical sources for all the Chinese provinces over 1978‐1995. Both parametric and non‐parametric methods are used to study the inequality between regions and between the rural and urban sub‐populations. The parametric approach is to test whether per capita incomes among provinces converged over time. The non‐parametric approach is the calculation and decomposition of the Gini coefficient by population sub‐group and income source.

Findings

The results show no evidence of growth convergence in per capita GDP, income and expenditure across provinces, but clear evidence of divergence in per capita rural (and urban) incomes and total expenditures. Three‐quarters of inter‐provincial income inequality are explained by inter‐rural/urban inequality. Inter‐provincial inequality explains more than half of rural inequality and less than half of urban inequality in most years.

Originality/value

This paper uses one of the most complicated datasets for the Chinese regions. It studies inequality using different economic indicators. It considers the different dimensions of inequality in China using two different approaches. The results are important for regional development policies.
A proactive assessment of sick building syndrome
Authors: Thomas‐Mobley Linda , Roper Kathy O. , Oberle Rita
Published: January 2005

Purpose

This paper describes a new proactive approach for facility managers to assess and manage complaints of “sick buildings”.

Design/methodology/approach

The assessment of the “sick building” syndrome problem is multifaceted and should include both objective data such as those collected and analyzed by industrial hygienists, and subjective data such as occupant perception measurements, usually gathered by surveys. The data for this research, both objective and subjective, were provided on a wide variety of office buildings and were analyzed using an artificial neural‐network based model.

Findings

Current literature on the subject suggests that the cause of poor indoor environments involves many variables interacting in an unlimited number of combinations. Using a blended definition of a narrowly defined “sick building”, a framework for a decision‐making support system for facility managers is provided.

Research limitations/implications

The data collection was limited to Southeastern US commercial office buildings, but the model has global applicability.

Practical implications

Recommendations are presented to help facility managers better understand the complex nature of the indoor environment based on this research.

Originality/value

This research and data analysis can be tailored to and is applicable to any building type.
Service skills for service workers: emotional intelligence and beyond
Authors: Varca Philip E.
Published: January 2005

This research documents the requisite skills for business‐to‐business service representatives. Using job observation and group interviews, a list of 28 potential service skills was developed and placed into a questionnaire format. Experienced service representatives rated the importance of these skills for job success, yielding a complex ability profile. These abilities dovetail with previous work discussing service provider characteristics, yet offer a more detailed and behaviorally oriented view of the worker skills that ensure effective service encounters. Implications for understanding service demands and staffing a workforce with the skills needed to deliver quality service are discussed.
Service quality measurements in ports of a developing economy: Nigerian ports survey
Authors: Ugboma Chinonye , Ibe Callistus , Ogwude Innocent C.
Published: January 2005

Identifies and assesses the key determinants of service quality and determines the quality of service offered by two ports in Nigeria using the SERVQUAL model. The main service attributes that are important to port users are determined. Relevant literature is reviewed to give relevance to the survey. Data for the study was collected via a well‐structured questionnaire, analysed, and perception‐expectation gap scores evaluated. Reveals that the service offered at Port Harcourt had a favorable influence on actual perceptions of quality of service and that there is improved service at the port in comparison with Lagos. Reveals that port managers focus on those dimensions which receive lowest ratings and attributes with high gap scores. This is a single‐industry (port) survey, thus raising doubts about the generalizability of the results. Reveals that port managers should be looking carefully at each of the dimensions where customers perceive receiving a different service than expected. Managers should also be in regular contact with employees in order to assess their service experiences. Shows how using SERVQUAL to identify important attributes of port service quality could be used as an early warning system for ports, thus being an important tool for managers.
Thermal analysis of micro‐channel heat exchangers with two‐phase flow using FEM
Authors: Hegde Pradeep , Seetharamu K.N. , Quadir G.A. , Aswathanarayana P.A. , Abdullah M.Z. , Zainal Z.A.
Published: January 2005

Purpose

To analyze two‐phase flow in micro‐channel heat exchangers used for high flux micro‐electronics cooling and to obtain performance parameters such as thermal resistance, pressure drop, etc. Both uniform and non‐uniform micro‐channel base heat fluxes are considered.

Design/methodology/approach

Energy balance equations are developed for two‐phase flow in micro‐channels and are solved using the finite element method (FEM). A unique ten noded element is used for the channel descritization. The formulation also automatically takes care of single‐phase flow in the micro‐channel.

Findings

Micro‐channel wall temperature distribution, thermal resistance and the pressure drop for various uniform micro‐channel base heat fluxes are obtained, both for single‐ and two‐phase flows in the micro‐channel. Results are compared against data available in the literature. The wall temperature distribution for a particular case of non‐uniform base heat flux is also obtained.

Research limitations/implications

The analysis is done for a single micro‐channel and the effects of multiple or stacked channels are not considered. The analysis needs to be carried out for higher heat fluxes and the validity of the correlation needs to be ascertained through experimentation. Effects of flow mal‐distribution in multiple channels, etc. need to be considered.

Practical implications

The role of two‐phase flow in micro‐channels for high flux micro‐electronics cooling in reducing the thermal resistance is demonstrated. The formulation is very useful for the thermal design and management of microchannels with both single‐ and two‐phase flows for either uniform or non‐uniform base heat flux.

Originality/value

A simple approach to accurately determine the thermal resistance in micro‐channels with two‐phase flow, for both uniform and non‐uniform base heat fluxes is the originality of the paper.
Application of computational fluid dynamics simulation tools for thermal characterization of electronic packages
Authors: Kandasamy Ravi , Subramanyam Suresh
Published: January 2005

Purpose

In the semiconductor electronics industry, effective heat removal from the integrated circuits (IC) chip, through the electronic package to the environment is crucial to maintain an allowable junction temperature of the IC chip. Thermal performances of such electronic packages are characterized by package thermal resistance called θ‐JA and are widely used in the electronic industry. Improving thermal performance is numerically predicted using computational fluid dynamics (CFD) technique and experimental tests are carried out to verify the numerical predictions. To provide new/additional data and demonstrate CFD technique for thermal characterization of electronic packages with experimental results.

Design/methodology/approach

The thermal performance of electronic packages has been studied using a CFD technique. The finite volume method is a technique used for solving a set of partial differential equations in a domain, using control volume based discretization. A detailed thermal model of an electronic package was created using a CFD tool and validated against the experimental data obtained in a natural convection environment, compliant to JEDEC standards. The thermal performance of the package was evaluated for different die sizes and epoxy molding compounds at different power levels. The use of a heat slug was investigated to identify its effect on heat dissipation for the future generations of IC, which are expected to be smaller in size and to dissipate more power. Free convective flow velocities, detailed temperature and heat flow distributions around the package will also be presented.

Findings

The study demonstrates that applying CFD techniques can provide accurate results on estimating thermal characterization of an electronic package. Predicted device junction temperatures as well as the thermal resistance of packages can be predicted with a good accuracy for different ranges of power levels in natural convection. The numerically estimated die junction temperatures have also been found to be accurate and reliable.

Research limitations/implications

The analysis is limited to an incompressible fluid. The effect of forced convection is not considered.

Practical implications

New and additional generated data will be helpful in the design and decision making time of the product to choose a low cost and viable thermal performance solution in the cooling of electronic components at low power.

Originality/value

The electronic package involves multi‐material and applying CFD technique is useful to determine the accurate thermal performance and simple and fast to apply for different conditions/material sets. Predictions of junction‐to‐ambient thermal resistance and device junction temperature values are compared against measurements. Excellent correlation was obtained. The results thus obtained compare well with the experimental results, but the computational effort and time required in the analysis is much small as compared.
Taking power seriously in strategic organizational learning
Authors: Voronov Maxim , Yorks Lyle
Published: January 2005

Purpose

This paper argues that failing to grasp thoroughly the influence of power on the strategy‐making process can severely inhibit the potential of strategy making as a vehicle of organizational learning.

Design/methodology/approach

First the organizational learning perspective on strategic management is sketched and an attempt is made to show how it takes the social aspects of organizing more seriously than earlier perspectives on strategy. It is also noted how this iteration responds or at least has the potential to respond to some of the critiques directed at earlier thinking on strategy from critical management studies (CMS). Then CMS's critique of organizational learning theories is noted and the critiques to re‐conceptualize blockages to learning and knowledge creation are built on.

Findings

An attempt has been made to show that, as in earlier perspectives on strategy, there is still insufficient attention being paid to the role of power in strategic change. This places severe limitations on strategic learning that is possible.

Originality/value

Concludes by joining other writers in calling for a less managerialist research in strategy.
Action inquiry and performance appraisals
Authors: Walsh Kate , Fisher Dalmar
Published: January 2005

Purpose

Introduces the primary concepts behind the practice of action inquiry. Then, examines what current literature suggests about components of the performance appraisal process and identifies areas where applying action inquiry concepts can add a new dimension to our current understanding.

Design/methodology/approach

Applies action inquiry, a concept from the organizational learning and change literatures, to suggest ways to infuse meaning and mutuality into appraisal discussions to help organizational leaders and members learn and develop. Ways to do so are demonstrated through a review and discussion of seven principal research streams in the current appraisal literature.

Findings

An action inquiry approach can address many of the limitations inherent in the appraisal process and refocus appraisals as developmental tools. Potentially, appraisals can act as forums to open dialogue, invite participation and build relationships around re‐visioning one's work and career. The process can become instrumental to continual quality improvement and organizational growth suggests that a rich opportunity exists to make the performance appraisal process developmentally meaningful for individuals and potentially transformative for organizations.

Originality/value

Discusses seven themes addressed in performance appraisal research and poses new possibilities that emerge when these themes are examined through an action inquiry lens.