bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Analysis of Determinants for Spike Glycoprotein Assembly into Murine Coronavirus Virions: Distinct Roles for Charge-Rich and Cysteine-Rich Regions of the Endodomain
Authors: Ye Rong , Montalto-Morrison Cynthia , Masters Paul S.
Published: August 2004

The coronavirus spike protein (S) forms the distinctive virion surface structures that are characteristic of this viral family, appearing in negatively stained electron microscopy as stems capped with spherical bulbs. These structures are essential for the initiation of infection through attachment of the virus to cellular receptors followed by fusion to host cell membranes. The S protein can also mediate the formation of syncytia in infected cells. The S protein is a type I transmembrane protein that is very large compared to other viral fusion proteins, and all except a short carboxy-terminal segment of the S molecule constitutes the ectodomain. For the prototype coronavirus mouse hepatitis virus (MHV), it has previously been established that S protein assembly into virions is specified by the carboxy-terminal segment, which comprises the transmembrane domain and the endodomain. We have genetically dissected these domains in the MHV S protein to localize the determinants of S incorporation into virions. Our results establish that assembly competence maps to the endodomain of S, which was shown to be sufficient to target a heterologous integral membrane protein for incorporation into MHV virions. In particular, mutational analysis indicated a major role for the charge-rich carboxy-terminal region of the endodomain. Additionally, we found that the adjacent cysteine-rich region of the endodomain is critical for fusion of infected cells, confirming results previously obtained with S protein expression systems.
Diverse Roles for E4orf3 at Late Times of Infection Revealed in an E1B 55-Kilodalton Protein Mutant Background
Authors: Shepard Robin N. , Ornelles David A.
Published: August 2004

Species C human adenovirus mutants that fail to express open reading frame 3 of early region 4 (E4orf3) are phenotypically indistinguishable from the wild-type virus when evaluated in cells cultured in vitro. However, E4orf3 gene function has been productively studied in the context of additional viral mutations. This study identifies diverse roles for the E4orf3 protein that are evident in the absence of early region 1B 55-kDa protein (E1B-55K) function. In an E1B-55K-deficient background, the E4orf3 protein promotes viral replication by increasing both the burst size and the probability that an infected cell will produce virus. Early viral gene expression is not impaired in E1B-55K/E4orf3 double mutant virus-infected cells. Cells infected with the double mutant virus accumulated concatemers of viral DNA. However, the E1B-55K/E4orf3 double mutant virus did not replicate any better in MO59J cells, in which viral DNA concatemers did not accumulate, than in MO59K cells, in which viral DNA concatemers were produced, suggesting that viral DNA concatenation is not the primary growth defect of the E1B-55K/E4orf3 double mutant virus. Accumulation of viral mRNA in the nucleus and cytoplasm of E1B-55K/E4orf3 double mutant virus-infected cells was severely reduced compared to that on wild-type virus-infected cells. Thus, in an E1B-55K mutant background, the E4orf3 protein promotes the accumulation of late viral RNA and enhances late gene expression. Finally, within the context of an E1B-55K mutant virus, the E4orf3 protein acts to suppress host cell translation and preserve the viability of cells at moderately late times of infection.
The Vaccinia Virus G1L Putative Metalloproteinase Is Essential for Viral Replication In Vivo
Authors: Hedengren-Olcott Marika , Byrd Chelsea M. , Watson Jeffrey , Hruby Dennis E.
Published: August 2004

The function of the putative metalloproteinase encoded by the vaccinia virus
G1L
gene is unknown. To address this question, we have generated a vaccinia virus strain in which expression of the
G1L
gene is dependent on the addition of tetracycline (TET) when infection proceeds in a cell line expressing the tetracycline repressor. The vv
tetOG1L
virus replicated similarly to wild-type Western Reserve (WR) virus in these cells when TET was present but was arrested at a late stage in viral maturation in the absence of TET. This arrest resulted in the accumulation of 98.5% round immature virus particles compared to 6.9% at a similar time point when TET was present. Likewise, the titer of infectious virus progeny decreased by 98.9% ± 0.97% when the vv
tetOG1L
virus was propagated in the absence of TET. Mutant virus replication was partially rescued by plasmid-encoded G1L, but not by G1L containing an HXXEH motif mutated to RXXQR. Modeling of G1L revealed a predicted structural similarity to the α-subunit of
Saccharomyces cerevisiae
mitochondrial processing peptidase (α-MPP). The HXXEH motif of G1L perfectly overlaps the HXXDR motif of α-MPP in this model. These results demonstrate that
G1L
is essential for virus maturation and suggest that G1L is a metalloproteinase with structural homology to α-MPP. However, no obvious effects on the expression and processing of the vaccinia virus major core proteins were observed in the
G1L
conditional mutant in the absence of TET compared to results for the TET and wild-type WR controls, suggesting that G1L activity is required after this step in viral morphogenesis.
Molecular Determinants within the Surface Proteins Involved in the Pathogenicity of H5N1 Influenza Viruses in Chickens
Authors: Hulse Diane J. , Webster Robert G. , Russell Rupert J. , Perez Daniel R.
Published: August 2004

Although it is established that the cleavage site and glycosylation patterns in the hemagglutinin (HA) play important roles in determining the pathogenicity of H5 avian influenza viruses, some viruses exist that are not highly pathogenic despite possessing the known characteristics of high pathogenicity (i.e., their HA contains multiple basic amino acids at the cleavage site and has glycosylation patterns similar to that of the highly pathogenic H5 viruses). Currently little is known about the H5N1 viruses that fall into this intermediate category of pathogenicity. We have identified strains of H5N1 avian influenza viruses that have markers typical of high pathogenicity but distinctly differ in their ability to cause disease and death in chickens. By analyzing viruses constructed by reverse-genetic methods and containing recombinant HAs, we established that amino acids 97, 108, 126, 138, 212, and 217 of HA, in addition to those within the cleavage site, affect pathogenicity. Further investigation revealed that an additional glycosylation site within the neuraminidase (NA) protein globular head contributed to the high virulence of the H5N1 virus. Our findings are in agreement with previous observations that suggest that the activities of the HA and NA proteins are functionally linked.
Effects of the Δ67 Complex of Mutations in Human Immunodeficiency Virus Type 1 Reverse Transcriptase on Nucleoside Analog Excision
Authors: Boyer Paul L. , Imamichi Tomozumi , Sarafianos Stefan G. , Arnold Edward , Hughes Stephen H.
Published: August 2004

Long-term use of combination therapy against human immunodeficiency virus type (HIV-1) provides strong selective pressure on the virus, and HIV-1 variants that are resistant to multiple inhibitors have been isolated. HIV-1 variants containing amino acid substitutions within the coding region of HIV-1 reverse transcriptase (RT), such as the 3′-azido-3′-deoxythymidine (AZT)-resistant variant AZT-R (M41L/D67N/K70R/T215Y/K219Q) and a variant containing an insertion in the fingers domain (S69SGR70/T215Y), are resistant to the nucleoside RT inhibitor (NRTI) AZT because of an increase in the level of excision of AZT monophosphate (AZTMP) from the primer. While rare, variants have also been isolated which contain deletions in the RT coding region. One such virus, described by Imamichi et al. (J. Virol74:10958-10964, 2000; J. Virol.74:1023-1028, 2000; J. Virol.75:3988-3992, 2001), contains numerous amino acid substitutions and a deletion of codon 67, which we have designated the Δ67 complex of mutations. We have expressed and purified HIV-1 RT containing these mutations. We compared the polymerase and pyrophosphorolysis (excision) activity of an RT with the Δ67 complex of mutations to wild-type RT and the two other AZT-resistant variants described above. All of the AZT-resistant variants we tested excise AZTMP and 9-[2-(R)-(phosphonomethoxy)propyl]adenine (PMPA [tenofovir]) from the end of a primer more efficiently than wild-type RT. Although the variant RTs excised d4TMP less efficiently than AZTMP and PMPA, they were able to excise d4TMP more efficiently than wild-type RT. HIV-1 RT containing the Δ67 complex of mutations was not able to excise as broad a range of NRTIs as the fingers insertion variant SSGR/T215Y, but it was able to polymerize efficiently with low concentrations of deoxynucleoside triphosphates and seems to be able to excise AZTMP and PMPA at lower ATP concentrations than AZT-R or SSGR/T215Y, suggesting that a virus containing the Δ67 complex of mutations would replicate reasonably well in quiescent cells, even in the presence of AZT.
Out of the Smokescreen: does an anti-smoking advertisement affect young women’s perception of smoking in movies and their intention to smoke?
Authors: Edwards C A , Harris W C , Cook D R , Bedford K F , Zuo Y
Published: August 2004

Objective:To evaluate the effect of an anti-smoking advertisement on young women’s perceptions of smoking in movies and their intention to smoke.

Subjects/setting:2038 females aged 12–17 years attending cinemas in New South Wales, Australia.

Design/intervention:Quasi-experimental study of patrons, who were surveyed after having viewed a movie at their local cinema. The control group was surveyed during week 1 and the intervention group, during week 2. Before seeing the movie in week 2, a 30 second anti-smoking advertisement was shown, which featured a well known female actor drawing attention to the prevalence of smoking in movies.

Outcomes:Attitude of current smokers and non-smokers to smoking in the movies; intention of current smokers and non-smokers to be smoking in 12 months time.

Results:Among non-smokers, 48.2% of the intervention subjects thought that the smoking in the movie they viewed was “not OK” compared with 28.3% of the control subjects (p < 0.0001). However, there was no difference among smokers in the intervention (26.4%) and control (16.9%) groups (p  =  0.28). A higher percentage of current smokers in the intervention group indicated they were unlikely to smoke in 12 months time (47.8%) than smokers in the control condition (31.9%) (p  =  0.03). For non-smokers, there was no difference in smoking intentions between conditions, with 95% saying they would be unlikely to be smoking in 12 months time.

Conclusions:This “real world” study suggests that placing an anti-smoking advertisement before movies containing smoking scenes can help to “immunise” young women against the influences of film stars smoking.
Particulate matter from tobacco versus diesel car exhaust: an educational perspective: Figure 1
Authors: Invernizzi G , Ruprecht A , Mazza R , Rossetti E , Sasco A , Nardini S , Boffi R
Published: August 2004

Background:Air pollution is a common alibi used by adolescents taking up smoking and by smokers uncertain about quitting. However, environmental tobacco smoke (ETS) causes fine particulate matter (PM) indoor pollution exceeding outdoor limits, while new engines and fuels have reduced particulate emissions by cars. Data comparing PM emission from ETS and a recently released diesel car are presented.

Methods:A 60 m3garage was chosen to assess PM emission from three smouldering cigarettes (lit sequentially for 30 minutes) and from a TDCi 2000cc, idling for 30 minutes.

Results:Particulate was measured with a portable analyser with readings every two minutes. Background PM10, PM2.5, and PM1levels (mean (SD)) were 15 (1), 13 (0.7), and 7 (0.6) μg/m3in the car experiment and 36 (2), 28 (1), and 14 (0.8) μg/m3in the ETS experiment, respectively. Mean (SD) PM recorded in the first hour after starting the engine were 44 (9), 31 (5), and 13 (1) μg/m3, while mean PM in the first hour after lighting cigarettes were 343 (192), 319 (178), and 168 (92) μg/m3for PM10, PM2.5, and PM1, respectively (p < 0.001, background corrected).

Conclusions:ETS is a major source of PM pollution, contributing to indoor PM concentrations up to 10-fold those emitted from an idling ecodiesel engine. Besides its educational usefulness, this knowledge should also be considered from an ecological perspective.
The economic burden of smoking in California
Authors: Max W , Rice D P , Sung H-Y , Zhang X , Miller L
Published: August 2004

Objective:To develop estimates of the direct and indirect costs of smoking for California in 1999.

Methods:A prevalence based approach was used to estimate the annual costs of smoking. Econometric models were used to estimate the smoking attributable fraction (SAF) for direct costs (hospitalisations, ambulatory care, prescription drugs, home health care, and nursing home services) and indirect costs due to lost productivity from smoking related illness. The models controlled for socioeconomic factors and other risk behaviours. Epidemiological methods were used to estimate the SAF for indirect costs due to lost productivity from premature deaths. The SAFs were applied to total health care expenditures, days lost, and deaths to obtain smoking attributable total costs.

Results:In 1999, the total costs of smoking in California were $15.9 billion, $475 per resident, and $3331 per smoker. Direct costs were $8.6 billion (54% of the total), indirect costs due to lost productivity from illness were $1.5 billion (10%), and indirect costs due to premature deaths were $5.7 billion (36%). The cost of smoking was $9.4 billion for men and $6.3 billion for women. There were 43 137 deaths attributed to smoking, representing a total of 535 000 years of life lost. The value of life lost per death averaged $132 000, or 12.4 years.

Conclusions:California smoking related costs are high. The cost methodology presented is useful for other states and nations interested in estimating their costs of smoking. Cost estimates can be used to evaluate the level of cigarette taxes and other policies related to smoking.
Reaching youth at the point of sale: cigarette marketing is more prevalent in stores where adolescents shop frequently
Authors: Henriksen L , Feighery E C , Schleicher N C , Haladjian H H , Fortmann S P
Published: August 2004

Objective:Although numerous studies describe the quantity and nature of tobacco marketing in stores, fewer studies examine the industry’s attempts to reach youth at the point of sale. This study examines whether cigarette marketing is more prevalent in stores where adolescents shop frequently.

Design, setting, and participants:Trained coders counted cigarette ads, products, and other marketing materials in a census of stores that sell tobacco in Tracy, California (n  =  50). A combination of data from focus groups and in-class surveys of middle school students (n  =  2125) determined which of the stores adolescents visited most frequently.

Main outcome measures:Amount of marketing materials and shelf space measured separately for the three cigarette brands most popular with adolescent smokers and for other brands combined.

Results:Compared to other stores in the same community, stores where adolescents shopped frequently contained almost three times more marketing materials for Marlboro, Camel, and Newport, and significantly more shelf space devoted to these brands.

Conclusions:Regardless of whether tobacco companies intentionally target youth at the point of sale, these findings underscore the importance of strategies to reduce the quantity and impact of cigarette marketing materials in this venue.
The tobacco industry’s use of Wall Street analysts in shaping policy
Authors: Alamar B C , Glantz S A
Published: August 2004

Objective:To document how the tobacco industry has used Wall Street analysts to further its public policy objectives.

Methods:Searching tobacco documents available on the internet, newspaper articles, and transcripts of public hearings.

Results:The tobacco industry used nominally independent Wall Street analysts as third parties to support the tobacco industry’s legislative agenda at both national and state levels in the USA. The tobacco industry has, for example, edited the testimony of at least one analyst before he testified to the US Senate Judiciary Committee, while representing himself as independent of the industry.

Conclusion:The tobacco industry has used undisclosed collaboration with Wall Street analysts, as they have used undisclosed relationships with research scientists and academics, to advance the interests of the tobacco industry in public policy.
Stereotyping the smoker: adolescents’ appraisals of smokers in film
Authors: McCool J P , Cameron L , Petrie K
Published: August 2004

Objective:To assess the relation between demographic factors and film smoking stereotypes in adolescents and the potential influence of smoker stereotypes on smoking susceptibility.

Design:A cross sectional questionnaire survey of school students (n  =  3041) aged 12–13 and 16–17 years who were asked to describe the personal characteristics of female and male smokers in films.

Setting:15 primary or intermediate schools and 10 secondary schools in Auckland, New Zealand.

Results:Appraisals of smokers in film were strongly influenced by age and sex with younger adolescents and males more likely to see female smokers as sexy, intelligent and healthy whereas older students and females more often appraised female smokers as stressed bored and depressed. Overall, image stereotypes (sexy, stylish) were more likely to be significantly associated with smoking susceptibility than emotional sensitivity stereotypes (stressed, depressed etc).

Conclusions:Adolescents differ significantly in their appraisal of smokers in films; however, image based stereotypes, rather than emotional sensitivity stereotypes, are significantly associated with smoking susceptibility.
Psychosocial work conditions, social capital, and daily smoking: a population based study
Authors: Lindström M
Published: August 2004

Objective:To investigate the associations between psychosocial conditions at work, social capital/social participation, and daily smoking.

Design/setting/participants/measurements:The 2000 public health survey in Scania is a cross sectional postal questionnaire study with a 59% participation rate. A total of 5180 persons aged 18–64 years that belonged to the work force and the unemployed were included in this study. Logistic regression models were used to investigate the associations between psychosocial factors at work/unemployment, social participation, and daily smoking. Psychosocial conditions at work were defined according to the Karasek-Theorell demand–control/decision latitudes into relaxed, active, passive, and jobstrain categories. The multivariate analyses included age, country of origin, education and economic stress.

Results:17.2% proportion of all men and 21.9% of all women were daily smokers. The jobstrain (high demands/low control) and unemployed categories had significantly higher odds ratios of daily smoking among both men and women compared to the relaxed (low demands/high control) reference category. The passive (low demands/low control), jobstrain, and unemployed categories were also significantly associated with low social participation. Low social participation was significantly and positively associated with daily smokingwithineach of the psychosocial work conditions and unemployed categories.

Conclusions:The positive association between low social capital/low social participation and daily smoking is well known. However, both social participation and daily smoking are associated with psychosocial work conditions and unemployment. Psychosocial work conditions and unemployment may affect daily smoking both directly and through a pathway including social participation.
Sweet and spicy flavours: new brands for minorities and youth: Figure 1
Authors: Connolly G N
Published: August 2004

The tobacco industry is now adding sweet and spicy flavours to its products in order to increase sales to youth and minorities
Fusaric acid, aFusarium verticillioidesmetabolite, antagonistic to the endophytic biocontrol bacteriumBacillus mojavensis
Authors: Bacon C W , Hinton D M , Porter J K , Glenn A E , Kuldau G
Published: August 2004

An endophytic bacterium, Bacillus mojavensis Roberts, Nakamura & Cohan, was patented as a nonpathogenic biocontrol for plant diseases. However, before this bacterium can be used as a biocontrol agent, it must be evaluated against homologous competing organisms, some of which are equally successful endophytes, such as species of Fusarium that are symptomless endophytes, especially on maize. Preliminary field trials using this bacterium as a biocontrol agent against production of the fumonisin mycotoxins caused by infection of maize with Fusarium verticillioides (Sacc.) Nirenberg (= Fusarium moniliforme Sheldon) was less than that observed with greenhouse studies. Fusarium verticillioides and other species produce fusaric acid. Fusaric acid at concentrations as low as 22 µmol/L accounted for a 41% reduction in CFU compared with the control group, while concentrations of 223 µmol/L and higher resulted in total toxicity to the bacterium. Mutants of F. verticillioides that produced low concentrations of fusaric acid did not affect the endophytic CFU of the bacterium in seedlings. These results suggest that fusaric acid accounted for the reduction of bacterial colonization and the resulting poor biocontrol activity and suggested its importance to the fungus is as an antibiotic, which assists in the in planta competition for the intercellular niche colonized by F. verticillioides during its endotrophic state.Key words: Fusarium moniliforme, Fusarium verticillioides, bacterial endophyte, fungal endophyte, fumonisin.
Devriesia, a new hyphomycete genus to accommodate heat-resistant, cladosporium-like fungi
Authors: Seifert Keith A , Nickerson Nancy L , Corlett Michael , Jackson Eric D , Louis-Seize Gerry , Davies Robert J
Published: August 2004

Three new species of heat-resistant fungi related to the hyphomycete Cladosporium staurophorum (Kendrick) M.B. Ellis were isolated from heat-treated soil from commercial lowbush blueberry fields and other sites in eastern Canada. Cladosporium staurophorum and the three new species produce characteristic dark, multicelled chlamy dospores. Phylogenetic analysis of nuclear ribosomal internal transcribed spacer DNA sequences suggest that these four species form a monophyletic group that is marginal in the Mycosphaerellaceae and phylogenetically distinct from Cladosporium sensu stricto. The new genus Devriesia is described for C. staurophorum, the three new species, and a fifth species originally described as Cladosporium chlamydosporis. A key to distinguish the five accepted species is provided. The species of the genus are dimorphic and share similar cladosporium-like conidial anamorphs consisting of pale brown, short, acropetally produced chains of cylindrical to fusiform, zero- or one-septate conidia and ramoconidia, diagnostic chlamydosporic synanamorphs, and a soil-borne, heat-resistant ecology. Devriesia acadiensis N.L. Nickerson & Seifert, with clover-shaped chlamydospores, Devriesia shelburniensis N.L. Nickerson & Seifert, with large, multi celled chlamydospores, and Devriesia thermodurans N.L. Nickerson & Seifert, with few-celled, clavate chlamy dospores, are described as new species. Chlamydospores from cultures of D. acadiensis, Devriesia staurophora, and D. thermodurans germinated after exposure to 75 °C for 30 min. Germination of these spores was activated by a heat shock. Chlamydospores from cultures of C. shelburniensis did not germinate after heat exposure.Key words: dematiaceous hyphomycetes, heat-resistant fungi, lowbush blueberries, Vaccinium angustifolium, ITS rDNA phylogeny.
Early results from field trials using Hypholoma fasciculare to reduce Armillaria ostoyae root disease
Authors: Chapman Bill , Xiao Guoping , Myers Sheldan
Published: August 2004

Armillaria ostoyae (Romagn.) Herink. causes serious damage to forest tree species worldwide. In this study, Hypholoma fasciculare (Huds. ex Fr.) Kummer was inoculated, after logging, into areas in south-central British Columbia that had been identified as having high levels of A. ostoyae. Hypholoma fasciculare was successfully established in a variety of different types of trials, as indicated by growth of H. fasciculare mycelium into roots of inoculated stumps and the presence of fruiting bodies on and around stumps. Three to five years after treatment, inoculated plots had biologically and statistically significantly lower levels of mortality attributable to A. ostoyae.Key words: Hypholoma fasciculare, Armillaria, biocontrol, woody debris.
Is growth performance in rubber (Hevea brasiliensis) clones related to xylem hydraulic efficiency?
Authors: Sangsing Krissada , Cochard Hervé , Kasemsap Poonpipope , Thanisawanyangkura Sornprach , Sangkhasila Kumut , Gohet Eric , Thaler Philippe
Published: August 2004

Hydraulic efficiency, xylem pressure, and stomatal conductance were measured in two Hevea clones having contrasting growth performances in their immature phase. Hydraulic efficiency was estimated by the xylem resistance on a leaf area basis on stem, petiole segments, and whole branches. The fast-growing clone exhibited significantly higher xylem efficiency, higher stomatal conductance, and higher xylem pressure. The difference in xylem pressure between the two clones was quantitatively consistent with the differences in hydraulic resistance and leaf transpiration rates. Our results suggest that variations in xylem efficiency may explain variations in stomatal conductance and xylem pressure, and hypothetically, growth performance between Hevea clones.Key words: xylem, hydraulic conductance, hydraulic architecture, water relations, rubber tree, Hevea.
Host microtubules in the Hartig net region of ectomycorrhizas, ectendomycorrhizas, and monotropoid mycorrhizas
Authors: Kuga-Uetake Yukari , Purich Melissa , Massicotte Hugues B , Peterson R. Larry
Published: August 2004

Various categories of mycorrhizas are recognized primarily by the structural changes that occur between fungi and roots. In all mycorrhiza categories, cytological modifications of root cells accompany the establishment of the functional symbiosis, and among these are alterations in the organization of the cytoskeleton. Using immuno labelling combined with confocal scanning laser microscopy, this study documents changes in microtubules (MTs) in root cells of ectendomycorrhizas and monotropoid mycorrhizas; in addition, ectomycorrhizas were reinvestigated to determine the effect of fungal colonization on host root cells. In Pinus banksiana L.  Laccaria bicolor (Maire) Orton ectomycorrhizas, MTs were present in epidermal and cortical cells adjacent to the Hartig net. The remaining cortical MTs had a different organization when compared with those of cortical cells of control roots. MTs were present in Hartig net hyphae. In ectendomycorrhizas formed when roots of P. banksiana were colonized by the ascomycete, Wilcoxina mikolae var. mikolae Yang & Korf, MTs were present adjacent to intracellular hyphae and host nuclei, but few cortical MTs were present. MTs were present within Hartig net and intracellular hyphae. In field-collected roots of Monotropa uniflora L., MTs were associated with fungal pegs, intracellular extensions of inner mantle hyphae within epidermal cells. The close association between MTs and fungal pegs may be related to the formation of the highly branched host-derived wall that envelops each fungal peg. The development of exchange interfaces in the three systems studied involve changes in the organization of microtubules.Key words: cytoskeleton, microtubules, Hartig net, mycorrhizas, immunolocalization, confocal microscopy.
Relativistic many-body calculations of energies for doubly-excited 1s2l2l′ and 1s3l3l′ states in Li-like ions
Authors: Safronova U I , Safronova M S
Published: August 2004

Energies of 1s2l2l′ and 1s3l3l′ states for Li-like ions with Z = 6100 are evaluated to second order in relativistic many-body perturbation theory. Second-order Coulomb and BreitCoulomb interactions are included. The calculations start with a Dirac potential and include all possible 1s2l2l′ and 1s3l3l′ configurations. Correction for the frequency dependence of the Breit interaction is taken into account in lowest order. The Lamb-shift correction to the energies is also included in lowest order. A detailed discussion of the various contributions to the energy levels is given for Li-like iron (Z = 26). We found that the three-electron corrections to the energy contribute about 1020% of the total second-order energy. Comparisons are made with available experimental data and excellent agreement for term splitting is obtained even for low-Z ions. These calculations are presented as a theoretical benchmark for comparison with experiment and theory.PACS Nos.: 32.30.Rj, 32.70.Cs, 31.25.Jf, 31.15.Md
The renormalization-group improved effective potential in the WessZumino model
Authors: McKeon D.G.C.
Published: August 2004

The one-loop correction to the effective potential in the massless WessZumino supersymmetric model is computed using operator regularization. The renormalization group is used to determine the scale dependence of the parameters characterizing the model (the coupling and background field strength) and to sum leading logarithm contributions to the effective potential to all orders of perturbation theory, using the method of characteristics. PACS No.: 11.30.Pb
Detailed analysis of magnetism in Ru monolayers
Authors: García-Cruz L M , Rubio-Ponce A , García A E , Baquero R
Published: August 2004

We study the magnetic behavior of a 4d transition-metal Ru monolayer (ML) on different substrates and orientations. In the ground state, an ideal Ru-ML is expected to be ferromagnetic on Ag(001) and Au(001) with a magnetic moment, µ, around 1.7 µB (Bohr magnetons) in both cases. On Cu(001), a Ru-ML is not magnetic. In this paper, we study the magnetic behavior of a Ru-ML at other orientations, i.e., (110) and (111), and analyze the phenomenon as a whole. We find magnetism on Au(111), and Ag(111) (µ ≈ 1 µB for both) but no magnetic activity on a Cu substrate in any orientation. This gives the first impression that the lattice parameter of the substrate is the one that governs the switching on of magnetism in the Ru-ML. But then, we find that on both Ag(110) and Au(110), an ideal Ru-ML is not magnetic. For that reason, we have tried to find another geometric parameter that would correlate better with the magnetic moment. We find that neither the total number of first nearest neighbors for each orientation, nor the number of them on the ML, or the number of them in the substrate, or the area per atom on the ML, correlate. We find a correlation with a parameter, Ω0, that represents the volume per atom in the monolayersubstrate interface region. But this parameter seems to have the wrong trend according to intuition. Further analysis shows that the details of the interaction are important, and that the physics underlying the switching on of magnetism in a Ru-ML on noble metal substrates, is determined by an intraband transfer of d-electronic states, from lower and higher energies to the Fermi level, that enhances the density of states at that energy, in an important way. This depends on specificities of the interaction between the ML and the substrate that are hardly taken into account by a single parameter that is merely geometric. PACS Nos.: 75.10b, 75.30m, 75.70.Ak, 73.20.At
A NOTE ON NON-AMENABILITY OF ℬ(ℓp) FOR p=1,2
Authors: OZAWA NARUTAKA
Published: August 2004

This is an expository note on non-amenabilty of the Banach algebra ℬ(ℓp) for p=1,2. These were proved respectively by Connes (p=2) and Read (p=1) by very different methods. We give a single proof which reproves both.
MOMENT FORMULAS FOR THE QUASI-NILPOTENT DT-OPERATOR
Authors: AAGAARD LARS , HAAGERUP UFFE
Published: August 2004

Let T be the quasi-nilpotent DT-operator. By use of Voiculescu's amalgamated R-transform we compute the moments of (T-λ1)*(T-λ1) where [Formula: see text], and the Brown-measure of [Formula: see text], where Y is a circular element *-free from T for ∊>0. Moreover we give a new proof of Śniady's formula for the moments τ(((T*)kTk)n) for k,n∈ℕ.
ANOMALOUS NORMAL STATE PROPERTIES OF UNDERDOPED Bi 2212 THIN FILMS
Authors: STIUFIUC G. , STIUFIUC R. , MACOCIAN E. , RAFFY H. , ILONCA G.
Published: August 2004

We investigate the effect of the opening of the pseudogap on the temperature dependence of the in-plane resistivity ρab(T) for Bi 2212 epitaxial thin films having different oxygen contents. Using successive annealing treatments we were able to bring the films from a maximally overdoped state (characterized by a T c of 63 K) to a strongly underdoped state (T c <10 K ). We also observed a significant change in the temperature dependence of the in-plane resistivity ρab(T). This dependence presents two major characteristics: for the overdoped sample we observed an upward curvature from linearity while for underdoped samples we observed a downturn from linearity starting from a characteristic temperature T* which will be associated with the opening of the pseudogap in the excitation spectrum.
LATTICE SIMULATION OF NASCENT PEPTIDE FOLDING
Authors: ZHUO JIAFENG , ZHANG LINSEN , CHEN CHANGJUN , HE YI , XIAO YI
Published: August 2004

The nascent peptide folding in vivo is different from the denatured peptide refolding in vitro and can be divided into two stages. In the first stage, the peptide is folding as it is being synthesized until the whole peptide chain is synthesized. The final conformation formed in this stage is called as nascent state. In the second stage, the protein folds beginning with the nascent state formed in the first stage into the native state. We use a lattice model to simulate these two stages and investigate the folding time of the nascent peptide comparing with that of the denatured peptide refolding. Our results show that the synthesis process may affect the folding time of the nascent peptide. This may be helpful to understand why the former folds faster than the latter.
HEAT TREATMENT EFFECT ON CaO–P2O5–SiO2–Fe2O3 GLASS-CERAMICS STRUCTURE
Authors: SIMON V. , ENIU D. , NEUMANN M. , SIMON S.
Published: August 2004

The heat treatment carried out at different temperatures between 1000 and 1200°C for the same time and under similar conditions leads to differences in the elemental composition and therefore in the ratio of the component elements on the sample surface. They are evidenced by changes in O1s core level XPS spectra. The ratio of bridging oxygen (BO) to non-bridging oxygen (NBO) in iron containing CaO – SiO 2– P 2 O 5 glasses changes differently for the glass ceramic sample resulting from heat treatment carried out at 1000°C and for those obtained at higher treatment temperatures.
STRUCTURAL AND DIELECTRIC PROPERTIES OF Ba0.5Sr0.5TiO3 THIN FILMS GROWN ON LAO WITH HOMO-EPITAXIAL LAYER FOR TUNABLE APPLICATIONS
Authors: SEKHAR M. CHANDRA
Published: August 2004

The epitaxial, single phase (100) Ba 0.5 Sr 0.5 TiO 3 (BST) films with thin interfacial layer of BST (x=0.4) were deposited on LAO (100) substrates using Pulse Laser Deposition (PLD). These films were characterized in terms of their phase formation and structural growth characteristics using X-ray diffraction and Atomic Force Microscopy respectively. The dielectric properties are strongly affected by the substrate type, post deposition annealing time, and temperature. In order to verify all these properties, thin interfacial-buffer layers of BST (10, 20, 50 nm) were introduced to relieve the stress induced between the film and the substrate. The variations of dielectric constant and ferroelectric properties of as deposited films are discussed in detail. The high tunability, low dielectric loss and low leakage current of these films make them attractive candidates for fabricating tunable dielectric devices. The observed dielectric properties of the BST-films are attributed to homo-epitaxial interfacial layer, which is responsible for the increase in the dielectric constant and tunability.
THE "FOLDING" BEHAVIORS OF HOMOPOLYMERS WITH ONE END FIXED
Authors: XUE BIN , WANG JUN , WANG WEI
Published: August 2004

We study the "folding" behaviors of homopolymers with one end fixed. By using canonical ensemble molecular dynamics simulation method, we observe the conformational changes during folding processes. Long chains collapse to the helical nuclei, then regroup to helix from the free-end to form the compact conformations through the middle stages of helix-like coil and helix-like cone, while short chains do not apparently have the above mentioned middle stages. Through simulated annealing, the native conformation of homopolymer chain in our model is found to be helix. We show the relations between specific heat C v (T) and radius of gyration R g (T) as functions of temperature, chain length and the interaction strength, respectively. We find that these two quantities match well and can be combined to interpret the "folding" process of the homopolymer. It is found that the collapse temperature Tθ and the native-like folding temperature T f do not change with the chain length in our model, however the interaction strength affects the values of Tθ and T f .
PERCOLATION AND TUNNELING IN COMPOSITE MATERIALS
Authors: BALBERG I. , AZULAY D. , TOKER D. , MILLO O.
Published: August 2004

Classical percolation theory is concerned with the onset of geometrical connectivity and the accompanied onset of electrical connectivity in disordered systems. It was found, however, that in many systems, such as various composites, the geometrical and electrical onsets of the connectivity are not simultaneous and the correlation between them depends on physical processes such as tunneling. The difference between the above two types of systems and the consequences for the electrical transport properties of the latter composites have been largely ignored in the past. The application of scanning local probe microscopies and some recent theoretical developments have enabled a better understanding of the latter systems and their sometimes "strange" behavior as bona fide percolation systems. In this review we consider the above issues and their manifestation in three types of systems: Carbon Black–Polymer composites, metal–insulator cermets and hydrogenated microcrystalline silicon.
INTERPLAY BETWEEN SINGLE PARTICLE COHERENCE AND KINETIC ENERGY DRIVEN SUPERCONDUCTIVITY IN DOPED CUPRATES
Authors: MA TIANXING , GUO HUAIMING , FENG SHIPING
Published: August 2004

Within the kinetic energy driven superconducting mechanism, the interplay between the single particle coherence and superconducting instability in doped cuprates is studied. The superconducting transition temperature increases with increasing doping in the underdoped regime, and reaches a maximum in the optimal doping, then decreases in the overdoped regime, however, the values of this superconducting transition temperature in the whole superconducting range are suppressed to low temperature due to the single particle coherence. Within this superconducting mechanism, we calculate the dynamical spin structure factor of cuprate superconductors, and reproduce all main features of inelastic neutron scattering experiments in the superconducting-state.
INFRARED ABSORPTION IN PARTIALLY DISORDERED K2CuCl4·2H2O-TYPE COMPOUNDS
Authors: GRADO-CAFFARO M. A. , GRADO-CAFFARO M.
Published: August 2004

An approximate relationship for the coefficient of optical absorption valid, in principle, for the infrared range, corresponding to K 2 CuCl 4·2 H 2 O -type compounds is derived from a model for electronic density of states. These compounds are assumed to be partially disordered from the point of view of the general theory of solids.
AN UPPER BOUND FOR THE GROWTH OF CONJUGACY CLASSES IN TORSION-FREE WORD HYPERBOLIC GROUPS
Authors: COORNAERT MICHEL , KNIEPER GERHARD
Published: August 2004

We give a new upper bound for the growth of primitive conjugacy classes in torsion-free word hyperbolic groups.
ON THE LINEAR COMPLEXITY OF SOME GENERALIZED CYCLOTOMIC SEQUENCES
Authors: PARK YOUNG-HO , HONG DEUKJO , EUN HICHUN
Published: August 2004

Cunsheng Ding computed the linear complexity of generalized cyclotomic binary sequences of order 2 with respect to p2, but made a mistake in his computation. These errors affect his main theorem seriously. We correct the errors and re-establish the main theorem.
MINIMAL EXPANSIONS OF SEMILATTICES
Authors: JIPSEN P. , KISIELEWICZ A.
Published: August 2004

We determine the minimal extension of the sequence <0,1,1,…,1,2>. This completes and extends the work of Koh, started in 1970, and solves Problem 15 in the survey on pn-sequences and free spectra [4]. The results involve the investigation of some minimal expansions of semilattices.
QUADRATIC ALGEBRAS OF SKEW TYPE SATISFYING THE CYCLIC CONDITION
Authors: JESPERS ERIC , OKNIŃSKI JAN
Published: August 2004

We consider algebras over a field with generators x1,x2,…,xn subject to [Formula: see text] square-free relations xixj=xkxl in which every product xpxq, p≠q, appears in one of the relations. The work of Gateva-Ivanova and Van den Bergh, motivated in particular by the study of set theoretic solutions of the Yang–Baxter equation, provided an important class of such algebras. In this special case the presentation satisfies the so-called cyclic condition that became an essential combinatorial tool in proving that these algebras share many strong ring theoretic properties of polynomial algebras in commuting variables. In this paper we describe the structure of algebras on four generators satisfying the cyclic condition. The emphasis is on some new unexpected features, not present in the motivating special classes.
ON THE STRUCTURE OF INCIDENCE RINGS OF GROUP AUTOMATA
Authors: KELAREV A. V.
Published: August 2004

The Jacobson radical is one of the major tools used in the investigation of the structure of rings and ring constructions. Our main theorem gives a complete description of the Jacobson radicals of incidence rings of group automata for all finite nilpotent groups.
PATTERN FORMATION IN CULTURES OFBACILLUS SUBTILIS
Authors: HARTMANN DIRK
Published: August 2004

Colonies of Bacillus subtilis that grow on the surface of thin agar plates show various complex spatio-temporal patterns depending on environmental conditions. Based on experimental observations, a new model is constructed in the context of reaction-diffusion equations. We have verified numerically that this model is able to reproduce the experimentally obtained morphology diagrams. Furthermore, the model has been simplified to study the spreading via nonlinear diffusion in more detail. In particular, we have shown that traveling waves exhibit a diffusive-interface instability, which is observed in the experiments.
WAVELET ANALYSIS OF LOW BACK SURFACE EMG SIGNALS SUBJECT TO UNEXPECTED LOAD
Authors: POPE M. H. , PANAGIOTACOPULOS N. D. , STIELAU W. , FRIESEN K. , LEE J. S.
Published: August 2004

This study reports a new technique for the analysis of electromyographic signals from the low back muscles. More specifically, the effect of unexpected load on a normal subject and a subject with chronic low back pain was determined and quantified using wavelet based analysis (Morlet wavelet). The analysis was performed using a Wavelet software system, subsequently referred to as PSCW. The system identified automatically, accurately, and in a uniquely reproducible manner the time response of the erector spinae muscle. The exact number of responses as well as their corresponding time and amplitude were determined and tabulated. It was observed that the initial reaction time for the normal subject was faster than the reaction time for the subject chronic low back pain. The importance of this observation may help in the understanding of the physiology of the neuromuscular system associated with low back spine disorders. It is believed that an occupational and clinical test based on this observation that could give an accurate assessment of the status of low back disorder could be designed. Based on this assessment a rehabilitation program could be developed with the objective of improving the condition of a spine disorder (decrease the initial response time) by muscle strengthening.
ANALYSIS OF THE DOPPLER ULTRASOUND SIGNAL BY WAVELET PACKET TRANSFORM
Authors: MEGHNEFI F. , REGUIG F. BEREKSI , BRAHAMI M.
Published: August 2004

The study presented in this paper is concerned with the analysis of the ultrasound Doppler signal of the arteries in the spectro-temporal domain using the wavelet packet transform. The spectro-temporal representation is obtained by the decomposition of the Doppler signal in frequency sub-band, using filter banks associated with a well chosen wavelet. It is shown that the decomposition level depends on the stationarity of the Doppler signal, and the best profile of blood flow velocity in arteries is obtained according to an appropriate choice of wavelet type.

Three types of wavelets have been tested on two Doppler signals previously recorded from the carotid and femoral arteries. The best representation is obtained when the frequency sub-bands of the filter bank associated with chosen wavelet are regularly distributed in the frequency domain and the level of decomposition is 7.
EVALUATION OF A COMPUTER-SIMULATION MODEL FOR HUMAN AMBULATION ON STILTS
Authors: PAN CHRISTOPHER S. , MILLER KIMBERLY M. , CHIOU SHARON , WU JOHN Z.
Published: August 2004

Stilts are elevated tools that are frequently used by construction workers to raise workers 18 to 40 inches above the ground without the burden of erecting scaffolding or a ladder. Some previous studies indicated that construction workers perceive an increased risk of injury when working on stilts. However, no in-depth biomechanical analyses have been conducted to examine the fall risks associated with the use of stilts. The objective of this study is to evaluate a computer-simulation stilts model. Three construction workers were recruited for walking tasks on 24-inch stilts. The model was evaluated using whole body center of mass and ground reaction forces. A PEAK™ motion system and two Kistler™ force platforms were used to collect data on both kinetic and kinematic measures. Inverse- and direct-dynamics simulations were performed using a model developed using commercial software — ADAMS and LifeMOD. For three coordinates (X, Y, Z) of the center of mass, the results of univariate analyses indicated very small variability for the mean difference between the model predictions and the experimental measurements. The results of correlation analyses indicated similar trends for the three coordinates. Plotting the resultant and vertical ground reaction force for both right and left feet showed small discrepancies, but the overall shape was identical. The percentage differences between the model and the actual measurement for three coordinates of the center of mass, as well as resultant and vertical ground reaction force, were within 20%. This newly-developed stilt walking model may be used to assist in improving the design of stilts.