bluuebunny/crossref_metadata_2025_split huggingface dataset:
CovS/CovR of group B streptococcus: a two‐component global regulatory system involved in virulence
Authors: Lamy Marie‐Cécile , Zouine Mohammed , Fert Juliette , Vergassola Massimo , Couve Elisabeth , Pellegrini Elisabeth , Glaser Philippe , Kunst Frank , Msadek Tarek , Trieu‐Cuot Patrick , Poyart Claire 
Published: November 2004

SummaryIn this study, we carried out a detailed structural and functional analysis of a Streptococcus agalactiae (GBS) two‐component system which is orthologous to the CovS/CovR (CsrS/CsrR) regulatory system of Streptococcus pyogenes. In GBS, covR and covS are part of a seven gene operon transcribed from two promoters that are not regulated by CovR. A ΔcovSR mutant was found to display dramatic phenotypic changes such as increased haemolytic activity and reduced CAMP activity on blood agar. Adherence of the ΔcovSR mutant to epithelial cells was greatly increased and analysis by transmission electron microscopy revealed the presence at its surface of a fibrous extracellular matrix that might be involved in these intercellular interactions. However, the ΔcovSR mutant was unable to initiate growth in RPMI and its viability in human normal serum was greatly impaired. A major finding of this phenotypic analysis was that the CovS/CovR system is important for GBS virulence, as a 3 log increase of the LD50 of the mutant strain was observed in the neonate rat sepsis model. The pleiotropic phenotype of the ΔcovSR mutant is in full agreement with the large number of genes controlled by CovS/CovR as seen by expression profiling analysis, many of which encode potentially secreted or cell surface‐associated proteins: 76 genes are repressed whereas 63 were positively regulated. CovR was shown to bind directly to the regulatory regions of several of these genes and a consensus CovR recognition sequence was proposed using both DNase I footprinting and computational analyses.
Mutations in ribosomal protein L3 and 23S ribosomal RNA at the peptidyl transferase centre are associated with reduced susceptibility to tiamulin in Brachyspira spp. isolates
Authors: Pringle Märit , Poehlsgaard Jacob , Vester Birte , Long Katherine S. 
Published: November 2004

SummaryThe pleuromutilin antibiotic tiamulin binds to the ribosomal peptidyl transferase centre. Three groups of Brachyspira spp. isolates with reduced tiamulin susceptibility were analysed to define resistance mechanisms to the drug. Mutations were identified in genes encoding ribosomal protein L3 and 23S rRNA at positions proximal to the peptidyl transferase centre. In two groups of laboratory‐selected mutants, mutations were found at nucleotide positions 2032, 2055, 2447, 2499, 2504 and 2572 of 23S rRNA (Escherichia coli numbering) and at amino acid positions 148 and 149 of ribosomal protein L3 (Brachyspira pilosicoli numbering). In a third group of clinical B. hyodysenteriae isolates, only a single mutation at amino acid 148 of ribosomal protein L3 was detected. Chemical footprinting experiments show a reduced binding of tiamulin to ribosomal subunits from mutants with decreased susceptibility to the drug. This reduction in drug binding is likely the resistance mechanism for these strains. Hence, the identified mutations located near the tiamulin binding site are predicted to be responsible for the resistance phenotype. The positions of the mutated residues relative to the bound drug advocate a model where the mutations affect tiamulin binding indirectly through perturbation of nucleotide U2504.
Effect of calmidazolium on Ca2+ movement and proliferation in human osteosarcoma cells
Authors: Tseng Li‐Lin , Huang Chun‐Jen , Hsu Shu‐Shong , Chen Jin‐Shyr , Cheng He‐Hsiung , Chang Hong‐Tai , Jiann Bang‐Ping , Jan Chung‐Ren 
Published: November 2004

Summary1. In human MG63 osteosarcoma cells, the effect of calmidazolium on [Ca2+]i and proliferation was explored using fura‐2 and ELISA, respectively.2. Calmidazolium, at concentrations greater than 0.1 µmol/L, caused a rapid increase in [Ca2+]i in a concentration‐dependent manner (EC50 = 0.5 µmol/L). The calmidazolium‐induced [Ca2+]i increase was reduced by 66% by removal of extracellular Ca2+. In Ca2+‐free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+‐ATPase, caused a monophasic increase in [Ca2+]i, after which the effect of calmidazolium to increase [Ca2+]i was completely inhibited. U73122, an inhibitor of phospholipase C (PLC), abolished histamine (but not calmidazolium)‐induced increases in [Ca2+]i. Pretreatment with phorbol 12‐myristate 13‐acetate to activate protein kinase C inhibited the calmidazolium‐induced increase in [Ca2+]i in Ca2+‐containing medium by 47%.3. Separately, it was found that overnight treatment with 2–10 µmol/L calmidazolium inhibited cell proliferation in a concentration‐dependent manner.4. These results suggest that calmidazolium increases [Ca2+]i by stimulating extracellular Ca2+ influx and also by causing release of intracellular Ca2+ from the endoplasmic reticulum in a PLC‐independent manner. Calmidazolium may be cytotoxic to osteosarcoma cells.
Biofilm susceptibility to metal toxicity
Authors: Harrison Joe J. , Ceri Howard , Stremick Carol A. , Turner Raymond J. 
Published: November 2004

SummaryThis study compared bacterial biofilm and planktonic cell susceptibility to metal toxicity by evaluating the minimum inhibitory concentration (MIC), the planktonic minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) using the MBEC™ device. In total, 17 metal cations and oxyanions, chosen to represent groups VIB to VIA of the periodic table, were each tested on biofilm and planktonic cultures of Escherichia coli JM109, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. In contrast to control antibiotic assays, where biofilm cultures were 2 to 64 times less susceptible to killing than logarithmically growing planktonic bacteria, metal compounds killed planktonic and biofilm cultures at the same concentration in the vast majority of combinations. Our data indicate that, under the conditions reported, growth in a biofilm does not provide resistance to bacteria against killing by metal cations or oxyanions.
Isolation and characterization of soybean‐associated bacteria and their potential for plant growth promotion
Authors: Kuklinsky‐Sobral Júlia , Araújo Welington Luiz , Mendes Rodrigo , Geraldi Isaias Olívio , Pizzirani‐Kleiner Aline Aparecida , Azevedo João Lúcio 
Published: November 2004

SummaryEndophytic and epiphytic bacteria were isolated from two soybean cultivars (Foscarin and Cristalina). Significant differences were observed in bacterial population densities in relation to season of isolation, soybean growth phase and the tissues from which the isolates  were  obtained.  The  isolates  were  identified by partial 16S rDNA sequence analysis, with most of the isolates belonging to the Pseudomonaceae, Burkholderiacea and Enterobacteriaceae groups. The potential of the isolates for plant growth promotion was evaluated by screening for indoleacetic acid (IAA) production and mineral phosphate solubilization; 34% of endophytic bacteria produced IAA and 49% were able to solubilize mineral phosphate whereas only 21% of epiphytic bacteria produced IAA although 52% were able to solubilize mineral phosphate. A high frequency of IAA producing isolates occurred in the early ripening Foscarin cultivar whereas a high percentage of phosphate solubilizing isolates were obtained from plants in the initial development stage (V6). We also found that 60% of endophytic and 69% of epiphytic isolates that produced IAA and solubilized mineral phosphate were also able to fix nitrogen in vitro. The soybean‐associated bacteria showing characteristics related to plant growth promotion were identified as belonging to the genera Pseudomonas, Ralstonia, Enterobacter, Pantoea and Acinetobacter.
Pili bigemini complicating diode laser hair removal
Authors: Kaniowska E 
Published: November 2004

SummaryAfter two diode laser treatments for hair removal, a 39‐year‐old woman was noted to have pili bigemini within the treated areas. It resolved after a third treatment. Pili bigemini, the appearance of two hairs coming from the same follicular opening, can be induced by intermediate doses of laser energy. It follows sublethal damage to the hair follicule apparatus.
Sunscreen application at the beach
Authors: Lademann J , Schanzer S , Richter H , Pelchrzim R V , Zastrow L , Golz K , Sterry W 
Published: November 2004

SummaryBackground  The sun protection factor (SPF) of sunscreens is determined after application of a standard amount. The European Cosmetic Toiletry and Perfumery Association (COLIPA) standard amount is 2 mg/cm2. Real‐life application of sunscreen is probably less than this.Aim  To determine the amount of sunscreen present on the skin of people at the beach.Methods  Volunteers at the beach were selected randomly and were not aware of being tested for the adequacy of their sunscreen application. All volunteers had applied sunscreen. Application had been more than 30 min before testing (sometimes up to 4 h earlier). The amounts of sunscreen applied to different body sites were determined quantitatively by tape stripping. Actual amounts of sunscreen applied were compared with the COLIPA standard. Also, sunscreen containing a fluorescent dye was applied to the skin of volunteers in a laboratory setting. The distribution of sunscreen application was visualized by UVA photography in a darkened room.Results  Sixty volunteers, 33 males and 27 females, aged 17–68 years (median 32 years), were recruited at the beach. Sunscreen coverage was inadequate at all body sites. Coverage at various body sites differed greatly. Most volunteers had applied 10% or less of the COLIPA standard amount to all body sites assessed. The best protected areas were the upper arm and décolleté but, even in these areas, most volunteers had only applied 10% of the COLIPA standard amount. The worst protected areas were the ears and top of the feet. The back was typically badly protected if treated by the volunteers themselves. The back was better protected if another person had applied the sunscreen. In the laboratory, the fluorescent dye‐containing sunscreen showed the same pattern of sunscreen application as at the beach.Conclusions  In real life, at the beach, very little sunscreen remains present on the skin.
Application of sunscreen preparations among young Polish people
Authors: Szepietowski Jacek C , Nowicka Danuta , Reich Adam , Melon Monika 
Published: November 2004

SummaryBackground  The efficacy of sunscreens is assessed on the basis that 15–20 g/m2 (1.5–2 mg/cm2) is applied. However, expecting people to apply such large amounts is perhaps unrealistic.Aim  To evaluate the application of sunscreen usage by young people.Materials and methods  Forty‐nine subjects (24 females and 25 males) in the age range 18–32 years (mean 23.1 years) were included in the study. They were asked to apply sun protection factor (SPF) to the whole of their own skin surface in just the same way that they would customarily do it during/prior to sun exposure. Two agents were applied: emulsion with SPF30 and a fatty cream with SPF > 60. The amount of preparation used/m2 was calculated. Statistical analysis was performed using the Student's t‐test.Results  The average amount of both preparations used was about half that expected to achieve correct sun protection (p < 0.00001). The mean applied amount of the fatty cream was 9.6 ± 5.3 g/m2 (50.7% of the ideal value) and the emulsion 9.2 ± 5.5 g/m2 (48.6% of the ideal value). Neither gender (male/female) nor type of agent (emulsion/fatty cream) affected the amount used.Conclusions  Young people customarily apply less than 10 g of SPF/m2. It is therefore unrealistic and possibly even misleading of manufacturers to assess SPF ratings as if people applied 15–20 g of SPF/m2. Perhaps it is for manufacture's to increase the efficacy of their products rather than for consumers to be asked to apply twice as much?
Plant phenology‐mediated indirect effects: The gall midge opens the phenological window wider for a leaf beetle
Authors: MIYAMOTO Yasushi , NAKAMURA Masahiro 
Published: November 2004

AbstractWe examined whether larvae of the gall midge Rabdophaga rigidae (Diptera: Cecidomyiidae) can modify the seasonal dynamics of the density of a leaf beetle, Plagiodera versicolora (Coleoptera: Chrysomelidae), by modifying the leaf flushing phenology of its host willow species, Salix serissaefolia and Salix eriocarpa (Salicaceae). To test this, we conducted field observations and a laboratory experiment. The field observations demonstrated that the leaf flushing phenology of the willows and the seasonal dynamics of the beetle density differed between shoots with stem galls and shoots without them. On galled shoots of both willow species, secondary shoot growth and secondary leaf production were promoted; consequently, leaf production showed a bimodal pattern and leaf production periods were 1 to 2 months longer than on non‐galled shoots. The adult beetle density on galled shoots was thus enhanced late in the season, and was found to change seasonally, synchronizing with the production of new leaves on the host willow species. From the results of our laboratory experiment, we attributed this synchrony between adult beetle density and willow leaf flush to beetles’ preference to eat new leaves rather than old. Indeed, beetles consumed five times more of the young leaves when they were fed both young and old leaves. These results indicate that stem galls indirectly enhance the adult beetle density by enhancing food quality and quantity late in the beetle‐feeding season. We therefore conclude that midge galls widen the phenological window for leaf beetles by extending the willows’ leaf flush periods.
Distribution of the oceanic insects Halobates (Hemiptera: Gerridae) off the south coast of Japan
Authors: IKAWA Terumi , OKABE Hidehiko , HOSHIZAKI Sugihiko , KAMIKADO Takahiro , CHENG Lanna 
Published: November 2004

AbstractSpecimens of ocean skaters Halobates were collected off the south coast of Japan in the East China Sea in 1995, and from the Kumano‐nada Sea to the East China Sea in 1998 and 1999. Three species were identified: H. micans, H. germanus and H. sericeus. We found two species co‐occurring in comparable densities in different years, a phenomenon not hitherto reported in other regions of the ocean. We discuss distributions of the three Halobates species with special reference to the influence of the Kuroshio Current, temporal variations of sea‐surface temperature, and monsoonal winds.
Biosystematic study of Issikiocrania japonicella Moriuti (Lepidoptera: Eriocraniidae), with description of immature stages
Authors: MIZUKAWA Hitomi , HIROWATARI Toshiya , HASHIMOTO Satoshi 
Published: November 2004

AbstractThe larval and pupal morphology of the eriocraniid species Issikiocrania japonicella Moriuti, 1982 is examined and described for the first time. Unique characters on the thorax and the ninth abdominal segment were recognized in the larval chaetotaxy, but evaluation of the characters remains unresolved. Redescription of the adult morphology, including mouth parts, wing markings and venation, and male and female genitalia, is also given. Four new localities are recorded from Aomori, Nagano, Aichi and Osaka prefectures. Fagus crenata Blume (Fagaceae) was determined as the larval host plant from rearings. The morphology of adult and immature stages suggests that Issikiocrania is a unique genus that retains many primitive features.
Bone level change at implant‐supported fixed partial dentures with and without cantilever extension after 5 years in function
Authors: Wennström Jan , Zurdo Jose , Karlsson Stig , Ekestubbe Annika , Gröndahl Kerstin , Lindhe Jan 
Published: November 2004

AbstractObjective: The aim of this study was to retrospectively analyze whether the inclusion of cantilever extensions increased the amount of marginal bone loss at free‐standing, implant‐supported, fixed partial dentures (FPDs) over a 5‐year period of functional loading.Material and Methods: The patient material comprised 45 periodontally treated, partially dentate patients with a total of 50 free‐standing FPDs supported by implants of the Astra Tech® System. Following FPD placement (baseline) the patients were enrolled in an individually designed supportive care program. A set of criteria was collected at baseline to characterize the FPDs. The primary outcome variable was change in peri‐implant bone level from the time of FPD placement to the 5‐year follow‐up examination. The comparison between FPDs with and without cantilevers was performed at three levels: FPD level, implant level, and surface level. Bivariate analysis was performed by the use of the Mann–Whitney U‐test and stepwise regression analysis was utilized to evaluate the potential influence of confounding factors on the change in peri‐implant bone level.Results: The overall mean marginal bone loss for the implant‐supported FPDs after 5 years in function was 0.4 mm (SD, 0.76). The bone level change at FPDs placed in the maxilla was significantly greater than that for FPDs in the mandible (0.6 versus 0.2 mm; p<0.05). No statistically significant differences were found with regard to peri‐implant bone level change over the 5 years between FPDs with and without cantilevers at any of the levels of comparisons. The multivariate analysis revealed that the variables jaw of treatment and smoking had a significant influence on peri‐implant bone level change on the FPD level, but not on the implant or surface levels. The model explained only 10% of the observed variance in the bone level change.Conclusion: The study failed to demonstrate that the presence of cantilever extensions in an FPD had an effect on peri‐implant bone loss.
A BIOLOGICALLY MOTIVATED ASSOCIATIVE MEMORY ARCHITECTURE
Authors: MILES COE F. , ROGERS DAVID 
Published: November 2004

A synthesis of analytical techniques from the fields of biology, mathematics, computer science and engineering are used to model the information processing characteristics of the mammalian cerebellar cortex. By viewing anatomically different neurons as representing network elements whose input-output functions are different, a mechanism for distributing information throughout the memory is proposed. The functional circuitry developed to implement this feature is called the microcircuit. Overlapping microcircuit activity is used to describe the memory's read and write operations. Key features of the memory model include: (1) its use of a sparse interconnection network, (2) its ability to manipulate very large input patterns, (3) its distributed storage of input data patterns and (4) its statistical reconstruction of stored patterns during memory read operations. Quantitative measures for the memory's recall fidelity and storage capacity are derived and results of computer simulations are presented.
FAST LEARNING OF BIASED PATTERNS IN NEURAL NETWORKS
Authors: WENDEMUTH A. , SHERRINGTON D. 
Published: November 2004

Usual neural network gradient descent training algorithms require training times of the same order as the number of neurons N if the patterns are biased. In this paper, modified algorithms are presented which require training times equal to those in unbiased cases which are of order 1. Exact convergence proofs are given. Gain parameters which produce minimal learning times in large networks are computed by replica methods. It is demonstrated how these modified algorithms are applied in order to produce four types of solutions to the learning problem: 1. a solution with all internal fields equal to the desired output, 2. the Adaline (or pseudo-inverse) solution, 3. the perceptron of optimal stability without threshold and 4. the perceptron of optimal stability with threshold.
PARTON DISTRIBUTIONS IN THE NUCLEON AND THE PAULI PRINCIPLE
Authors: BUCCELLA FRANCO , SOFFER JACQUES 
Published: November 2004

The Pauli principle is used, together with some deep inelastic scattering data, to guide us in making reasonable assumptions for various polarized parton distributions in terms of unpolarized distributions. We relate the violation of the Gottfried and Ellis-Jaffe sum rules and we anticipate a substantial violation of the Bjorken sum rule.
RENORMALIZATION OF FERMI VELOCITY IN A COMPOSITE TWO DIMENSIONAL ELECTRON GAS
Authors: WEGER M. , BURLACHKOV L. 
Published: November 2004

We calculate the self-energy Σ(k, ω) of an electron gas with a Coulomb interaction in a composite 2D system, consisting of metallic layers of thickness d ≳ a 0, where a 0 = ħ2∊1/ me 2 is the Bohr radius, separated by layers with a dielectric constant ∊2 and a lattice constant c perpendicular to the planes. The behavior of the electron gas is determined by the dimensionless parameters k F a 0 and k F c ∊2/∊1. We find that when ∊2/∊1 is large (≈5 or more), the velocity v(k) becomes strongly k-dependent near k F , and v ( k F ) is enhanced by a factor of 5-10. This behavior is similar to the one found by Lindhard in 1954 for an unscreened electron gas; however here we take screening into account. The peak in v(k) is very sharp (δ k/k F is a few percent) and becomes sharper as ∊2/∊1 increases. This velocity renormalization has dramatic effects on the transport properties; the conductivity at low T increases like the square of the velocity renormalization and the resistivity due to elastic scattering becomes temperature dependent, increasing approximately linearly with T. For scattering by phonons, ρ ∝ T 2. Preliminary measurements suggest an increase in v k in YBCO very close to k F .
CORRELATION EFFECTS IN NiO: COMPARISON OF NEAR THRESHOLD EXCITATION SPECTROSCOPIES
Authors: SCHEIPERS A. , MERZ H. 
Published: November 2004

At UHV-cleaved single-crystal NiO(100) surfaces core electron energy loss spectra (CEELS) at low primary energy and soft x-ray appearance potential spectra (SXAPS) have been measured at the oxygen K-threshold: the near-edge fine-structures have been investigated up to 40 eV above the threshold. Both spectroscopic methods probe in different ways the structure of the lowest empty states. CEELS is closely related to x-ray absorption spectroscopy (XAS), in both cases the excited final configuration consists of one core hole and one additional electron near the Fermi level E F. In APS we can study correlation effects very directly because the excited system consists of one core hole and two additional interacting electrons in localized resp. delocalized states near E F. The interpretation of the CEELS and SXAPS spectra at the oxygen K-edge is in agreement with a description of NiO as an intermediate valence system, where the charge-transfer gap is smaller than the Hubbard correlation energy. The comparison of our measured spectra with the experimental XAS of NiO shows the dominance of optically allowed channels in both spectroscopies.
NEW INTERMETALLIC COMPOUNDS IN THE TERNARY SYSTEM Yb-T-Al (T=Ag, Au, Pd, Pt)
Authors: CORDIER G. , HENSELEIT R. 
Published: November 2004

Structural characteristics of a number of ternary rare earth/transition metal/aluminium compounds are hexagonal nets of the AlB 2-type, Kagomé nets and tetragonal pyramides. Crystal structures of the new compounds in the ternary Yb-T-Al systems contain units and sections of them. Kagomé nets stacked in an ..ABAB.. sequence are observed in YbAg1.5Al0.5 ( MgZn 2-type). The crystal structure of Yb8Ag21Al45 is related to the BaHg 11-type. YbAu0.8Al3.2 ( CaZn 2 Al 2-type) contains tetragonal pyramides which are connected by common edges. Fragments of the AlB 2- and BaAl 4-type structure are present in Yb5Au15Al16. YbPdAl2 and YbPtAl2 ( YbPdAl 2-type) contain pentagonal prisms as the characteristic structural elements.