bluuebunny/crossref_metadata_2025_split huggingface dataset:
Depletion of Alveolar Macrophages Decreases the Dissemination of a Glucosylceramide-Deficient Mutant ofCryptococcus neoformansin Immunodeficient Mice
Authors: Kechichian Talar B. , Shea John , Del Poeta Maurizio 
Published: July 2007

ABSTRACTIn previous studies we showed that aCryptococcus neoformansmutant lacking glucosylceramide (Δgcs1) is avirulent and unable to reach the brain when it is administered intranasally into an immunocompetent mouse and is contained in a lung granuloma. To determine whether granuloma formation is key for containment ofC. neoformansΔgcs1, we studied the role ofC. neoformansglucosylceramide in a T- and NK-cell-immunodeficient mouse model (Tgε26) in which alveolar macrophages (AMs) are not activated and granuloma formation is not expected. The results show that Tgε26 mice infected with Δgcs1do not produce a lung granuloma and that the Δgcs1mutant proliferates in the lungs and does disseminate to the brain, although its virulence phenotype is dramatically reduced. Since Δgcs1can grow only in acidic niches, such as the phagolysosome of AMs, and not in neutral or alkaline environments, such as the extracellular spaces, we hypothesize that in immunodeficient mice Δgcs1proliferates inside AMs. Indeed, we found that depletion of AMs significantly improved Tgε26 mouse survival and decreased the dissemination of Δgcs1cells to the central nervous system. Thus, these results suggest that the growth of Δgcs1in immunodeficient mice is maintained within AMs. This study highlights the hypothesis that AMs may exacerbateC. neoformansinfection in conditions in which there is severe host immunodeficiency.
Occupation and adult onset of rhinitis in the general population
Authors: Radon K , Gerhardinger U , Schulze A , Zock J-P , Norback D , Toren K , Jarvis D , Held L , Heinrich J , Leynaert B , Nowak D , Kogevinas M ,   for the occupational group of the ECRHS study
Published: July 2007

Objectives:Occupational exposures have been associated with an increased risk of new-onset rhinitis in apprentices. However, population-based prospective data are scarce and do not cover new onset of rhinitis later in life. The authors studied the association between occupational exposure and adult onset of rhinitis prospectively.Methods:The data of 4994 participants (age at follow-up 28–57 years) from 27 centres of the European Community Respiratory Health Survey II who were symptom-free at baseline were analysed. As outcome at follow-up self-reported (a) nasal allergies (“allergic rhinitis”) and (b) runny, blocked nose for 12 months a year (“perennial rhinitis”) were used. Occupational exposures at any time during follow-up were defined by job title.Results:The cumulative incidence of allergic rhinitis, perennial rhinitis and both conditions was 12%, 11% and 3%, respectively. Compared to office workers, male medical professionals were at increased risk of new onset of allergic rhinitis (OR 3.0; 95% CI 1.4 to 6.4). Odds ratios were reduced in metal workers not involved in metal making or treating (0.3; 95% CI 0.1 to 0.7). For perennial rhinitis ORs were significantly increased in cleaners (1.4; 95% CI 1.0 to 2.1).Conclusions:Cleaners and medical professionals may be at increased risk for adult-onset rhinitis.
Mountain pine beetle associated blue-stain fungi cause lesions on jack pine, lodgepole pine, and lodgepole × jack pine hybrids in Alberta
Authors: Rice Adrianne V. , Thormann Markus N. , Langor David W. 
Published: July 2007

Mountain pine beetles ( Dendroctonus ponderosae Hopkins; (MPB)) have spread into lodgepole × jack pine hybrid ( Pinus contorta Douglas × Pinus banksiana Lambert) forests in Alberta and are predicted to spread into jack pine forests. Their success in these forests is uncertain but will be influenced by multiple factors, including the ability of their associated blue-stain fungi to colonize the trees and the health of the encountered trees. Healthy and dwarf mistletoe infected pines at three sites across Alberta (one site per pine species) were inoculated with three isolates each of Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield and Ophiostoma montium (Rumbold) von Arx. Both fungi grew and caused lesions on all hosts, suggesting that MPB will not be limited by a lack of fungal growth. Both fungi caused longer lesions in jack and hybrid pines than in lodgepole pines, indicating that susceptibility varies among hosts and is greater in the novel systems than in the co-evolved one. G. clavigera caused longer lesions than O. montium in hybrids and lodgepole pines, while the two species caused similar-sized lesions on jack pine. Intraspecific variation was high in G. clavigera, with one isolate producing much shorter lesions than the other two. Dwarf mistletoe infestation had little effect on infection lesion length.
Engineering nitrogen use efficiency with alanine aminotransferase
Authors: Good Allen G. , Johnson Susan J. , De Pauw Mary , Carroll Rebecka T. , Savidov Nic , Vidmar John , Lu Zhongjin , Taylor Gregory , Stroeher Virginia 
Published: July 2007

Nitrogen (N) is the most important factor limiting crop productivity worldwide. The ability of plants to acquire N from applied fertilizers is one of the critical steps limiting the efficient use of nitrogen. To improve N use efficiency, genetically modified plants that overexpress alanine aminotransferase (AlaAT) were engineered by introducing a barley AlaAT cDNA driven by a canola root specific promoter (btg26). Compared with wild-type canola, transgenic plants had increased biomass and seed yield both in the laboratory and field under low N conditions, whereas no differences were observed under high N. The transgenics also had increased nitrate influx. These changes resulted in a 40% decrease in the amount of applied nitrogen fertilizer required under field conditions to achieve yields equivalent to wild-type plants.
Calcium oxalate crystals in tribe Galegeae (Leguminosae) including foliar crystal macropattern development in Caragana frutex
Authors: Lersten Nels R. , Horner Harry T. 
Published: July 2007

Galegeae was reported in 1987 to be unique among papilionoid tribes because calcium oxalate crystals were shown to be mostly lacking. We surveyed leaves of 45 species from 20 genera, mostly from herbarium specimens. A living species ( Caragana frutex (L.) K. Koch) with crystals was also studied developmentally, important because only three other species have been similarly studied. Herbarium specimens and various stages of C. frutex leaflets were bleached, dehydrated, cleared in alcohol–xylol, and made permanent. Freehand sections of C. frutex were mounted in glycerine. Crystals were detected microscopically and are generally lacking among Galegeae genera. This supports tentative contemporary opinion that the tribe is unnatural. Crystals provide new, potentially useful systematic data. Variously differing unicellular trichomes were also described in the survey. Caragana frutex leaflets have a previously undescribed macropattern development: crystals form only along veins, except for late-season prisms in scattered palisade parenchyma. Crystals form progressively base to apex, first following along successive major veins from midvein to margin and then in later-developing smaller veins, progressing acropetally. The midvein remains almost crystal-free until leaflets are at or near full size. Crystal macropattern development in C. frutex leaflets suggests that crystallization may be influenced by the whole organ, as well as by individual cells.
Morphological and molecular studies on Resinicium s. str.
Authors: Nakasone Karen K. 
Published: July 2007

Resinicium Parmasto is typified by Resinicium bicolor (Alb. & Schwein.: Fr.) Parm., (Hymenochaetales, Basidiomycota), a readily recognized and widely distributed corticioid, lignicolous species in the northern hemisphere. Five new species of Resinicium closely allied to R. bicolor from the Caribbean region are described and illustrated: Resinicium confertum Nakasone, sp. nov., Resinicium monticola Nakasone, sp. nov., Resinicium mutabile Nakasone, sp. nov., Resinicium rimulosum Nakasone, sp. nov., and Resinicium tenue Nakasone, sp. nov. In addition, R. bicolor and Resinicium friabile Hjortstam & Melo are redescribed and illustrated. Sequence analyses of the internal transcribed spacer region support the recognition of the new taxa. Further, nuclear small subunit ribosomal RNA sequence data support the recognition of two groups of Resinicium species: the Resinicium s. str. group, including R. bicolor, and the Resinicium s.l. group that includes Resinicium furfuraceum (Bres.) Parm. The genus Resinicium is redefined and a key to the Resinicium s. str. species is provided.
New evaluation of proton structure corrections to hydrogen hyperfine splitting
Authors: Carlson Carl E 
Published: July 2007

We consider the proton structure corrections to the hydrogen ground-state hyperfine structure, focusing on a state-of-the-art evaluation of the inelastic nucleon corrections — the polarizability corrections — using analytic fits to the most recent data. We find a value for the fractional correction Δpol of 1.3 ± 0.3 ppm. This is 1–2 ppm smaller than the value of Δpol one would deduce using hyperfine-splitting data and elastic proton structure corrections obtained from modern form factor fits. In addition, we discuss the derivations of the relevant formulas, paying attention to lepton mass effects and to questions surrounding the use of unsubtracted dispersion relations. PACS Nos.: 31.30.Gs, 32.10.Fn, 14.20.Dh, 13.40.Gp
Fractality of emission of compound multiplicity in 12C–AgBr interactions at 4.5A GeV
Authors: Ghosh D , Deb A , Biswas S , Mandal P , Haldar P Kr. 
Published: July 2007

This paper presents a fractality analysis of the compound multiplicity (pions + target protons) distribution in 12C–AgBr interactions at 4.5A GeV in terms of moments proposed by Takagi (Phys. Rev. Lett. 72, 32 (1994)) for both emission-angle (θ) and azimuthal-angle (ϕ) space. The generalized dimensions Dq, q = 1 to 5, have been calculated and compared to other studies. The analysis reveals the multifractal nature of particle production as a common feature of emission of different patterns in high-energy nuclear collisions. PACS Nos.: 25.75–q, 24.60 Ky
MHD-mixed convection and mass transfer from a vertical stretching sheet with diffusion of chemically reactive species and space- or temperature-dependent heat source
Authors: El-Aziz Mohamed Abd , Salem Ahmed M 
Published: July 2007

The influence of chemical reactions on the problem of coupled heat and mass transfer by natural convection from a vertical stretching surface in the presence of a space- or temperature-dependent heat source effect is investigated. The sheet is stretched linearly in the presence of a uniform transverse magnetic field. The fluid is assumed to be viscous and incompressible. The governing differential equations are transformed by introducing similarity variables into a system of nonlinear ordinary differential equations and solving them numerically on the assumption of a small magnetic Reynolds number. The effects of the various parameters on the velocity, temperature, and concentration profiles as well as the local wall shear stresses, the local Nusselt number, and the local Sherwood number are presented graphically and in tabular form. An analysis of the results obtained shows that the flow field is influenced appreciably by the chemical reaction, heat source, magnetic field, and suction or injection at the sheet. PACS No.: 47.65.-d
Symmetry, quasisymmetry, and critical phenomena
Authors: Rowe D J 
Published: July 2007

This presentation is an analysis of the role of symmetry in second-order quantum phase transitions. It seeks to explain why transitions between phases of systems, associated with different symmetries, exhibit critical phenomena. It transpires that a system in one phase, tends to hold onto the symmetry associated with that phase until a breaking point is reached at which a rapid transition occurs to a new phase associated with a different symmetry. Understanding what is happening presents the challenge of explaining how a system "holds on" to a symmetry in the face of strong symmetry-breaking interactions. The explanation is of fundamental interest in physics, for understanding why models with built in symmetries often work extremely well even when the models ignore large symmetry-breaking interactions that are known to be present. When this phenomenon occurs, we say that the system has a quasidynamical symmetry. This concept is of interest in mathematics because it turns out that quasidyndamical symmetries are the physical realizations of a new concept in group theory, which we refer to as an embedded representation. PACS Nos.: 21.60.Fw, 21.60.Ev, 64.6–.Ht, 68.18.Jk
An improved installation for high-resolution laser spectroscopy on ion beams
Authors: Bazin M , Roy D , Larzillière M , el Idrissi M Chafik 
Published: July 2007

For many years, a complex installation has been developed in our laboratory for high-resolution laser spectroscopy of fast ion and neutral beams. Various results have been obtained for different species (H2, O2+, N2+, N2O+, and CO2+). The different spectroscopic techniques applicable to an accelerated beam are presented or recalled in this work to show the performance of the apparatus. Some difficulties in understanding the b4 Σ–g O2+ predissociation process led us to modify the molecular photofragment detection system and make it more efficient, as shown by the results presented. PACS No.: 39.30.+w
The spectrum of Yang–Mills theory in 2+1 dimensions, analytically
Authors: Leigh R G , Minic D , Yelnykov A 
Published: July 2007

We review our recent work on the glueball spectrum of pure Yang–Mills theory in 2 + 1 dimensions. The calculations make use of Karabali–Nair corner variables in the Hamiltonian formalism, and involve a determination of the leading form of the ground-state wave functional. PACS Nos.: 12.38.Lg, 11.15.Pg, 11.15.Tk
Decoherence-free subspaces and spontaneous emission cancellation
Authors: Marzlin K -P , Karasik R , Sanders B C , Whaley K B 
Published: July 2007

We establish the connection between decoherence-free subspaces of quantum information and spontaneous emission cancellation in quantum optics with molecules. Both phenomena rely on the destructive interference of transition amplitudes from two initial states to a common target state. We discuss physical similarities, differences, and limitations of both phenomena. PACS Nos.: 03.65.Yz, 42.50.–p, 03.67.Pp
Oscillatory thermoelectric effect in quasi-two-dimensional organic conductors in a magnetic field
Authors: Krstovska D , Galbova O 
Published: July 2007

A theoretical analysis is presented of the dependence of the thermoelectric power, when the temperature gradient is directed along the normal to the layers, in a layered conductor, with a quasi-two-dimensional electron energy spectrum on the magnitude and orientation of a strong magnetic field relative to the layers. The angular oscillations of the thermoelectric power, when the magnetic field is noticeably tilted from the normal to the layers result from the periodic dependence of the average electron velocity on the angle between the normal to the layers and the magnetic field. It is shown that, in a quantizing magnetic field at low temperatures, giant quantum oscillations of thermoelectric power as a function of both the magnetic field magnitude and the angle between the normal to the layers and the magnetic field occur. This quantum oscillation effect can be used with a high degree of accuracy as a good spectroscopic method for the experimental study of certain characteristics of a Fermi surface of quasi-two-dimensional organic conductors, such as the quasi-two-dimensionality parameter of the electron energy spectrum, cyclotron effective electron mass, and velocity distribution of charge carriers as well as an accurate determination of the extremal cross sections. PACS No.: 72.15.Jf
A modified Bethe Ansatz for the two-dimensional dimer problem
Authors: Schmidt J R 
Published: July 2007

The two-dimensional dimer problem is studied using the tools of modern solvable models. The transfer matrix is constructed from local monodromy matrices, and is diagonalized by a modified Bethe Ansatz that does not begin with a Bethe ground state, but rather with a pair of states transformed one into the other by the transfer matrix. The resulting Bethe eigenvectors have a structure very different from those constructed in other models from a ground state, and have some properties in common with the free-fermion eigenvectors of the squared transfer matrix encountered in the literature. PACS Nos.: 05.50+q, 02.10.Ox, 02.30.Ik, 05.20.–y
Identification and characterization of the regulatory elements of the inducible acetamidase operon from Mycobacterium smegmatis
Authors: Subbian Selvakumar , Narayanan Sujatha 
Published: July 2007

The highly inducible acetamidase promoter from Mycobacterium smegmatis has been used as a tool in the study of mycobacterial genetics. The 4.2 kb acetamidase operon contains four putative open reading frames (ORFs) (amiC, amiA, amiD, and amiS) upstream of the 1.2 kb acetamidase ORF (amiE). In this article, using electrophoretic mobility shift assay and promoter probe analyses with a lacZ reporter system, we show the position of three putative operators within the acetamidase operon in M. smegmatis. Results from these studies reinforce previous findings about the involvement of multiple promoters in the regulation of acetamidase gene expression. Each of the identified operators are positioned upstream of the respective promoter reported in previous studies. We also found that the crude cell lysate of M. smegmatis containing potential regulators, obtained from bacteria grown under inducing or noninducing conditions, binds to specific operators. The binding affinity of each operator with its cognate regulator is significantly different from the other. This supports not only the previous model of acetamidase gene regulation in M. smegmatis but also explains the role of these operators in controlling the expression of respective promoters under different growth conditions.
Ophiostoma species (Ascomycetes: Ophiostomatales) associated with bark beetles (Coleoptera: Scolytinae) colonizing Pinus radiata in northern Spain
Authors: Romón Pedro , Zhou XuDong , Iturrondobeitia Juan Carlos , Wingfield Michael J. , Goldarazena Arturo 
Published: July 2007

Bark beetles (Coleoptera: Scolytinae) are known to be associated with fungi, especially species of Ophiostoma sensu lato and Ceratocystis . However, very little is known about these fungi in Spain. In this study, we examined the fungi associated with 13 bark beetle species and one weevil (Coleoptera: Entiminae) infesting Pinus radiata in the Basque Country of northern Spain. This study included an examination of 1323 bark beetles or their galleries in P. radiata. Isolations yielded a total of 920 cultures, which included 16 species of Ophiostoma sensu lato or their asexual states. These 16 species included 69 associations between fungi and bark beetles and weevils that have not previously been recorded. The most commonly encountered fungal associates of the bark beetles were Ophiostoma ips , Leptographium guttulatum , Ophiostoma stenoceras , and Ophiostoma piceae . In most cases, the niche of colonization had a significant effect on the abundance and composition of colonizing fungi. This confirms that resource overlap between species is reduced by partial spatial segregation. Interaction between niche and time seldom had a significant effect, which suggests that spatial colonization patterns are rarely flexible throughout timber degradation. The differences in common associates among the bark beetle species could be linked to the different niches that these beetles occupy.
Survival ofEscherichia coliO157:H7 in soil and on lettuce after soil fumigation
Authors: Ibekwe A.  Mark , Grieve Catherine M. , Yang Ching-Hong 
Published: July 2007

Long-term survival of Escherichia coli O157:H7 in soil and in the rhizosphere of many crops after fumigation is relatively unknown. One of the critical concerns with food safety is the transfer of pathogens from contaminated soil to the edible portion of the plants. Multiplex fluorogenic polymerase chain reaction was used in conjunction with plate counts to quantify the survival of E. coli O157:H7 in soil after fumigation with methyl bromide and methyl iodide in growth chamber and microcosm laboratory experiments. Plants were grown at 20 °C in growth chambers during the first experiment and soils were irrigated with water contaminated with E. coli O157:H7. For the second experiment, soil microcosms were used in the laboratory without plants and were inoculated with E. coli O157:H7 and spiked with the two fumigants. Primers and probes were designed to amplify and quantify the Shiga-like toxin 1 (stx1) and 2 (stx2) genes and the intimin (eae) gene of E. coli O157:H7. Both fumigants were effective in reducing pathogen concentrations in soil, and when fumigated soils were compared with nonfumigated soils, pathogen concentrations were significantly higher in the nonfumigated soils throughout the study. This resulted in a longer survival of the pathogen on the leaf surface especially in sandy soil than observed in fumigated soils. Therefore, application of fumigant may play some roles in reducing the transfer of E. coli O157:H7 from soil to leaf. Regression models showed that survival of the pathogen in the growth chamber study followed a linear model while that of the microcosm followed a curvilinear model, suggesting long-term survival of the pathogen in soil. Both experiments showed that E. coli O157:H7 can survive in the environment for a long period of time, even under harsh conditions, and the pathogen can survive in soil for more than 90 days. This provides a very significant pathway for pathogen recontamination in the environment.
Citrate metabolism by Enterococcus faecium and Enterococcus durans isolated from goat’s and ewe’s milk: influence of glucose and lactose
Authors: Cabral María E. , Mukdsi María C. Abeijón , Medina de Figueroa Roxana B. , González Silvia N. 
Published: July 2007

Citrate metabolism by Enterococcus faecium ET C9 and Enterococcus durans Ov 421 was studied as sole energy source and in presence of glucose or lactose. Both strains utilized citrate as the sole energy source. Enterococcus faecium ET C9 showed diauxic growth in the presence of a limiting concentration of glucose. Neither strain used citrate until glucose was fully metabolized. The strains showed co-metabolism of citrate and lactose. Lactate, acetate, formate, and flavour compounds (diacetyl, acetoin, and 2,3-butanediol) were detected in both strains. The highest production of flavour compounds was detected during growth of E. durans Ov 421 in media supplemented with citrate–glucose and citrate–lactose. Citrate lyase was inducible in both strains. Acetate kinase activities presented the highest values in LAPTc medium, with E. faecium ET C9 displaying a specific activity 2.4-fold higher than E. durans. The highest levels of α-acetolactate synthase specific activity were detected in E. durans grown in LAPTc+g, in accordance with the maximum production of flavour compounds detected in this medium. Diacetyl and acetoinreductases displayed lower specific activity values in the presence of citrate. Enterococcus faecium and E. durans displayed citrate lyase, acetate kinase, α-acetolactate synthase, and diacetyl and acetoin reductase activities. These enzymes are necessary for conversion of citrate to flavour compounds that are important in fermented dairy products.