bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the Putative Type III Secretion ATPase CdsN (Cpn0707) ofChlamydophila pneumoniae
Authors: Stone Chris B. , Johnson Dustin L. , Bulir David C. , Gilchrist Jodi D. , Mahony James B. 
Published: August 2008

ABSTRACTType III secretion (T3S) is utilized by a wide range of gram-negative bacterial pathogens to allow the efficient delivery of effector proteins into the host cell cytoplasm through the use of a syringe-like injectisome.Chlamydophila pneumoniaeis a gram-negative, obligate intracellular pathogen that has the structural genes coding for a T3S system, but the functionality of the system has not yet been demonstrated. T3S is dependent on ATPase activity, which catalyzes the unfolding of proteins and the secretion of effector proteins through the injectisome. CdsN (Cpn0707) is predicted to be the T3S ATPase ofC. pneumoniaebased on sequence similarity to other T3S ATPases. Full-length CdsN and a C-terminal truncation of CdsN were cloned as glutathioneS-transferase (GST)-tagged constructs and expressed inEscherichia coli. The GST-tagged C-terminal truncation of CdsN possessed ATPase activity, catalyzing the release of ADP and Pifrom ATP at a rate of 0.55 ± 0.07 μmol min−1mg−1in a time- and dose-dependent manner. CdsN formed oligomers and high-molecular-weight multimers, as assessed by formaldehyde fixation and nondenaturing polyacrylamide gel electrophoresis. Using bacterial two-hybrid and GST pull-down assays, CdsN was shown to interact with CdsD, CdsL, CdsQ, and CopN, four putative structural components of theC. pneumoniaeT3S system. CdsN also interacted with an unannotated protein, Cpn0706, a putative CdsN chaperone. Interactions between CdsN, CdsD, and CopN represent novel interactions not previously reported for other bacterial T3S systems and may be important in the localization and/or function of the ATPase at the inner membrane ofC. pneumoniae.
The
yiaKLX1X2PQRS
and
ulaABCDEFG
Gene Systems Are Required for the Aerobic Utilization of
l
-Ascorbate in
Klebsiella pneumoniae
Strain 13882 with
l
-Ascorbate-6-Phosphate as the Inducer
Authors: Campos Evangelina , de la Riva Lucia , Garces Fernando , Giménez Rosa , Aguilar Juan , Baldoma Laura , Badia Josefa 
Published: August 2008

ABSTRACT

The capacity to both ferment and oxidize
l
-ascorbate has been widely documented for a number of enteric bacteria. Here we present evidence that all the strains of
Klebsiella pneumoniae
tested in this study ferment
l
-ascorbate using the
ula
regulon-encoded proteins. Under aerobic conditions, several phenotypes were observed for the strains. Our results showed that the
yiaK-S
system is required for this aerobic metabolic process. Gel shift experiments performed with UlaR and YiaJ and probes corresponding to the specific promoters indicated that
l
-ascorbate-6-phosphate is the effector molecule recognized by both regulators, since binding of the repressors to their recognition sites was impaired by the presence of this compound. We demonstrated that in
K. pneumoniae
cells
l
-ascorbate-6-phosphate is formed only by the action of the UlaABC phosphotransferase system. This finding explains why strains that lack the
ula
genetic system and therefore are unable to form the inducer intracellularly cannot efficiently use this vitamin as a carbon source under either anaerobic or aerobic conditions. Thus, efficient aerobic metabolism of
l
-ascorbate in
K. pneumoniae
is dependent on the presence of both the
yiaK-S
and
ula
systems. The expression of the
yiaK-S
operon, but not the expression of the
ula
regulon, is controlled by oxygen availability. Both systems are regulated by the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex and by IHF.
Accelerated Prion Disease Pathogenesis in Toll-Like Receptor 4 Signaling-Mutant Mice
Authors: Spinner Daryl S. , Cho In Soo , Park Seung Yong , Kim Jae Il , Meeker Harry C. , Ye Xuemin , LaFauci Giuseppe , Kerr Daniel J. , Flory Michael J. , Kim Bo Sook , Kascsak Regina B. , Wisniewski Thomas , Levis William R. , Schuller-Levis Georgia B. , Carp Richard I. , Park Eunkyue , Kascsak Richard J. 
Published: August 2008

ABSTRACTPrion diseases such as scrapie involve the accumulation of disease-specific prion protein, PrPSc, in the brain. Toll-like receptors (TLRs) are a family of proteins that recognize microbial constituents and are central players in host innate immune responses. The TLR9 agonist unmethylated CpG DNA was shown to prolong the scrapie incubation period in mice, suggesting that innate immune activation interferes with prion disease progression. Thus, it was predicted that ablation of TLR signaling would result in accelerated pathogenesis. C3H/HeJ (Tlr4Lps-d) mice, which possess a mutation in the TLR4 intracellular domain preventing TLR4 signaling, and strain-matched wild-type control (C3H/HeOuJ) mice were infected intracerebrally or intraperitoneally with various doses of scrapie inoculum. Incubation periods were significantly shortened in C3H/HeJ compared with C3H/HeOuJ mice, regardless of the route of infection or dose administered. At the clinical phase of disease, brain PrPSclevels in the two strains of mice showed no significant differences by Western blotting. In addition, compared with macrophages from C3H/HeOuJ mice, those from C3H/HeJ mice were unresponsive to fibrillogenic PrP peptides (PrP residues 106 to 126 [PrP106-126] and PrP118-135) and the TLR4 agonist lipopolysaccharide but not to the TLR2 agonist zymosan, as measured by cytokine production. These data confirm that innate immune activation via TLR signaling interferes with scrapie infection. Furthermore, the results also suggest that the scrapie pathogen, or a component(s) thereof, is capable of stimulating an innate immune response that is active in the central nervous system, since C3H/HeJ mice, which lack the response, exhibit shortened incubation periods following both intraperitoneal and intracerebral infections.
The C Terminus of Foamy Retrovirus Gag Contains Determinants for Encapsidation of Pol Protein into Virions
Authors: Lee Eun-Gyung , Linial Maxine L. 
Published: August 2008

ABSTRACT

Foamy viruses (FV) differ from orthoretroviruses in many aspects of their replication cycle. A major difference is in the mode of Pol expression, regulation, and encapsidation into virions. Orthoretroviruses synthesize Pol as a Gag-Pol fusion protein so that Pol is encapsidated into virus particles through Gag assembly domains. However, as FV express Pol independently of Gag from a spliced mRNA, packaging occurs through a distinct mechanism. FV genomic RNA contains
cis
-acting sequences that are required for Pol packaging, suggesting that Pol binds to RNA for its encapsidation. However, it is not known whether Gag is directly involved in Pol packaging. Previously our laboratory showed that sequences flanking the three glycine-arginine-rich (GR) boxes at the C terminus of FV Gag contain domains important for RNA packaging and Pol expression, cleavage, and packaging. We have now shown that both deletion and substitution mutations in the first GR box (GR1) prevented neither the assembly of particles with wild-type density nor packaging of RNA genomes but led to a defect in Pol packaging. Site-directed mutagenesis of GR1 indicated that the clustered positively charged amino acids in GR1 play important roles in Pol packaging. Our results suggest that GR1 contains a Pol interaction domain and that a Gag-Pol complex is formed and binds to RNA for incorporation into virions.
A Genetic Interaction between Hepatitis C Virus NS4B and NS3 Is Important for RNA Replication
Authors: Paredes Anne M. , Blight Keril J. 
Published: August 2008

ABSTRACT
Hepatitis C virus (HCV) nonstructural protein 4B (NS4B), a poorly characterized integral membrane protein, is thought to function as a scaffold for replication complex assembly; however, functional interactions with the other HCV nonstructural proteins within this complex have not been defined. We report that a Con1 chimeric subgenomic replicon containing the NS4B gene from the closely related H77 isolate is defective for RNA replication in a transient assay, suggesting that H77 NS4B is unable to productively interact with the Con1 replication machinery. The H77 NS4B sequences that proved detrimental for Con1 RNA replication resided in the predicted N- and C-terminal cytoplasmic domains as well as the central transmembrane region. Selection for Con1 derivatives that could utilize the entire H77 NS4B or hybrid Con1-H77 NS4B proteins yielded mutants containing single amino acid substitutions in NS3 and NS4A. The second-site mutations in NS3 partially restored the replication of Con1 chimeras containing the N-terminal or transmembrane domains of H77 NS4B. In contrast, the deleterious H77-specific sequences in the C terminus of NS4B, which mapped to a cluster of four amino acids, were completely suppressed by second-site substitutions in NS3. Collectively, these results provide the first evidence for a genetic interaction between NS4B and NS3 important for productive HCV RNA replication.
OPTIMIZATION OF THE MOLARITY OF NaOH AS PRECIPITATING AGENT FOR THE SYNTHESIS OF Ni FERRITE NANOCRYSTALLINE POWDERS BY COPRECIPITATION METHOD
Authors: DEHGHAN R. , EBRAHIMI S. A. SEYYED , BADIEI A. 
Published: August 2008

In this study, the effects of the molarity of the precipitating agent on the synthesis of nanostructured NiFe 2 O 4 powders by coprecipitation, followed by calcination were investigated and its optimum amount was also determined. Ni -ferrite powder was synthesized for the first time by dissolving Fe and Ni chlorides and ammonium ferrous sulfate in deionized water with different molar proportions. While stirring, the precipitating agent of NaOH was added to the solution with different molarities and after 1 hour of aging, the resultant precipitate was washed with deionized water and acetone. It was concluded that single phase nickel ferrite nanocrystalline powders can be prepared by use of 2.2M NaOH , with crystallite size of 30-50 nm.
ULTRAFINE PRIMARY SILICON PARTICLES IN PHOSPHORUS-MODIFIED HYPEREUTECTIC AL-SI ALLOY POWDERS PRODUCED BY SAMD METHOD
Authors: DELSHAD-KHATIBI P. , AKHLAGHI F. 
Published: August 2008

In the present study, alloy powder batches of Al-20Si (wt. %) were generated by SAMD technique using NaCl as the solid media. The method consists of introducing and mixing a specified amount of NaCl particles (mean diameter 254 μm) in aluminum melt at the temperature of 710°C. Melt disintegration occurs in 5 min by kinetic energy transfer from a rotating impeller (1400 rpm) to the metal via the solid atomizing medium ( NaCl particles). The resulting mixture of aluminum droplets and NaCl particles are subsequently quenched in water to dissolve NaCl and solidify Al droplets to produce powder particles. In order to investigate the effect of phosphorus modification on the size and morphology of the primary Si particles, the SAMD technique was also performed to produce Al-20Si -0.015P powder particles. The resultant powders were screened through 6 different sized sieves ranging from 38 to 500 μm and different powder fractions were cold mounted, polished and studied by optical microscopy. It was concluded that for both un-modified and modified alloys, there was a decrease in the size of primary Si particles corresponding to a decrease in the powder particle size. However, the same sized phosphorus modified powders exhibited considerably finer primary Si particles in which the average size of these ultrafine Si particles was about 1.1 μm for the smallest sieved particles.
Feminist social work research engaging with poststructural ideas
Authors: Wendt Sarah , Boylan Jane 
Published: August 2008

English This article draws on two empirical studies, one with women who had experienced domestic violence and the other with children and young people in public care. It presents reflections by two feminist social workers on how poststructuralism influenced their research practices in social work. French Cet article fait appel à deux études empiriques; la première auprès de femmes victimes de violence conjugale et la seconde auprès d'enfants et d'adolescents pris en charge par les services sociaux. Il présente les réflexions de deux travailleuses sociales féministes sur la façon dont le poststructuralisme a influencé leurs recherches en travail social. Spanish Este artículo llama la atención sobre dos estudios empíricos, uno con mujeres que tuvieron experiencias de violencia doméstica y el otro con niños y gente joven con cuidados públicos. Presenta reflexiones de dos trabajadoras sociales feministas, sobre cómo el post-estructuralismo ha influenciado sus prácticas de investigación en trabajo social.
A reflection on the indigenization discourse in social work
Authors: Huang Yunong  , Zhang Xiong  
Published: August 2008

English This article gives a brief review of the indigenization discourse in social sciences and in social work. We examine some assumptions and arguments by the proponents of indigenization in social work and suggest that attempts at indigenization may be less beneficial in some countries than assumed. French Cet article survole le thème de l'autochtonisation dans le domaine des sciences sociales et du travail social. Les auteurs y examinent quelques hypothèses et quelques arguments des tenants de l'autochtonisation en travail social et ils en arrivent à la conclusion que les tentatives d'autochtonisation peuvent se révéler moins porteuses que prévu dans certains pays. Spanish Este artículo ofrece una breve revisión soble el discurso de indigenización en las ciencias sociales y en el trabajo social. Examinamos algunos supuestos y argumentos de los partidarios de la indigenización en el trabajo social y sugerimos que los intentos de indigenización, en algunos países, pueden ser menos beneficiosos de lo que se asume.
Domestic violence services in Romania
Authors: Wimmer Jane S. , Harrington Pamela Awtrey 
Published: August 2008

English A domestic violence program in Sighisoara, Romania was developed as a partnership between a US university and a Romanian NGO through USAID funding. Goals included capacity building and direct service. This successful program was evaluated using a longitudinal case study methodology from 2003 to 2007. French Un programme pour contrer la violence conjugale a été mis au point à Sighisora, en Roumanie, par une ONG locale, en collaboration avec une université américaine, et avec l'appui financier de USAID. Les objectifs visaient le renforcement des capacités et la prestation de services. Ce programme porteur a été évalué de 2003 à 2007 en appliquant la méthode d'analyse de cas longitudinale. Spanish En Sighisoara, Rumania, ha sido desarrollado un programa para la violencia doméstica en colaboración entre una universidad norteamericana y una ONG rumana, a través de la USAID. Las metas incluyeron la formación de capacidades y el servicio directo. Este exitoso programa fue evaluado mediante una metodología de estudio de caso longitudinal, de 2003 a 2007.
Transracial adoption
Authors: Heimsoth DeAnna , Laser Julie Anne 
Published: August 2008

English Qualitative research investigated expatriate families living in China with adopted Chinese children and the manner in which living in China influenced the adoptees' acquisition of their culture of origin. The values and cultural practices of these expatriate parents are also examined. French Il s'agit d'une recherche qualitative qui explore la situation des familles expatriées vivant en Chine et ayant adopté des enfants Chinois. Plus particulièrement, cette recherche examine la façon dont le fait de vivre en Chine a influencé les enfants adoptés à intégrer leur culture d'origine. Les valeurs et les pratiques culturelles des parents expatriés sont également examinées. Spanish Mediante investigación cualitativa se estudió a las familias expatriadas que viven en China con sus niños adoptivos chinos, y la forma en que vivir en China ha influenciado en éstos la adquisición de su cultura de origen. También son examinados los valores y prácticas culturales de estos padres expatriados.
Brazilian street children
Authors: Fernandes Giselle T. , Vaughn Michael G. 
Published: August 2008

English This article reviews the socioeconomic and political context of substance misuse by street children in Brazil. Although findings are limited, available research reveals an urgent need for implementation of policies for street children. Programs for preventing substance misuse and delinquency are still missing political and infrastructural support. French Cette étude analyse le contexte politique et socioéconomique qui entoure le mauvais emploi de substances par les enfants de la rue du Brésil. Bien que les résultats soient limités, la recherche indique que l'établissement de politiques concernant les enfants de la rue est un enjeu urgent. Il n'y a pas encore de cadre politique et d'infrastructures pour soutenir les programmes de prévention de la consommation et de la délinquance. Spanish Este artículo revisa el contexto socioeconómico y político del fundamento del abuso de niños de la calle en Brasil. Aunque los hallazgos son limitados, la investigación disponible revela una urgente necesidad de implementación de políticas respecto a los niños de la calle. Los programas para prevenir el fundamento del abuso y la delincuencia aún están ausentes de apoyo político e infraestructural.
Sub-Saharan Africa's orphan crisis
Authors: Lombe Margaret , Ochumbo Alex 
Published: August 2008

English The dramatic increase in the number of children made vulnerable by AIDS in sub-Saharan Africa has necessitated research in treatment and prevention. We contribute to the current discussion on the orphan crisis by proposing a multifaceted approach utilizing institutional characteristics, with greater potential to strengthen community capacity and empower vulnerable children. French L'accroissement phénoménal des enfants vulnérabilisés par le SIDA en Afrique sub-saharienne a eu pour effet de stimuler la recherche en matière de traitements et de prévention. Cette étude s'inscrit dans la réflexion courante sur la crise des orphelinats et propose une approche multidimensionnelle qui tire parti des caractéristiques institutionnelles tout en renforçant les capacités des communautés et en redonnant davantage du pouvoir aux enfants vulnérables. Spanish El dramático incremento en el número de niños que se han hecho vulnerables por el SIDA, en el África Subsahariana, ha hecho necesaria la investigación en tratamiento y prevención. Nosotros aportamos a la discusión actual sobre la crisis de huérfanos, proponiendo un acercamiento multifacético, utilizando las características institucionales con mayor potencial para fortalecer la capacidad comunitaria y empoderar a los niños vulnerables.
A simple method for correcting time constant errors incurred in step scan systems
Authors: Fothergill I.R. , Neal W.E.J. 
Published: August 2008

The spatial variation of parameters such as temperature or flow velocity in a region of interest is frequently measured using scanning techniques and the results displayed on a chart recording. In certain instances it may be necessary to perform the scans manually using a time step procedure in order to maintain synchronism with the recording equipment. The sensor is moved in small equal steps with a fixed time delay at each location before moving to the next. Unless the delay is very much longer than the system time constant, including the sensor response, then time constant errors may result in the recorded measurements. This paper describes one of a number of techniques for correcting time constant errors incurred in these step scan systems. The method has the virtue of being simple to both understand and apply and sufficient background theory is included to convince the user that the approach is justified.
Digital algorithms for prediction, differentiation and integration
Authors: Forsythe W. 
Published: August 2008

The subject is dealt with in three parts, covered in three consecutive papers as follows. Part 1 presents a method of calculating the coefficients required in digital algorithms for prediction (including interpolation and extrapolation), differentiation and integration, both on and off line. It provides the means of computing rapidly, by hand or with the aid of a small calculator, the coefficients required for algorithms of any order up to eight. Parts 2 and 3, to be published in subsequent issues, will consider the errors inherent in using the algorithms derived in Part 1 and draw significant conclusions about the interaction of quantisation level, sampling frequency, order of the algorithm and the effects of these quantities on the accuracy of the results. Part 2 will deal with prediction and integration algorithms; Part 3 with differentiation.
PID algorithms and their computer implementation
Authors: Clarke D.W. 
Published: August 2008

Three-term or PID regulators are deservedly popular in industrial control systems. They give satisfactory performance for a wide class of processes, they are readily understood by technical plant personnel, and they are easy to implement using analogue or digital hardware. Stable elimination of offset due to load-disturbances is a principal control requirement, as in many cases processes are operated continuously at a fixed set-point Often this is achieved by the PI terms alone, though derivative action can be added for plant with excessive phase lag. In practice, however, nonlinear behaviour such as actuator saturation is a critical component of overall performance. This report discusses various forms of the PID regulator (positional, incremental, cascade, etc) and their closed-loop properties. Practical features such as avoidance of 'integral windup' and 'derivative kick' are described. The ways in which the PID algorithm can be discretised for use in a digital computer are outlined, together with appropriate Fortran coding. The effect of choice of sample interval on the discretised performance is analysed. Often the interval is chosen to be as short as possible given the computational power available; the influence of this on quantisation noise and offset is discussed Various filters are used in a discrete PID algorithm, including the anti-aliasing filter and a filter on derivative action. The properties of these filters are investigated and some interesting nonlinear filters, such as 'spike' filters are presented .
Recursive estimation for non-linear Weiner systems by on-line implementation of Bayes' rule
Authors: Jacobs O.L.R. 
Published: August 2008

Bayes'rule can be directly applied to estimation using noisy non-linear measurements in real systems. This requires an on-line computer to implement numerical computation of conditional probability distributions and their statistics: suitable machines are now routinely available for distributions of low dimensionality. Practical numerical problems can arise in connection with grid-scaling, prediction, and dimensionality. Gaussian approximation is well known as a way to avoid the first two of these: numerical results are included which demonstrate the power of this approximation. The main contribution of the paper is a novel linearisation which avoids the curse of dimensionality in Wiener systems where several random variables are observed through a noisy non-linear function of their weighted sum. The work was motivated by case studies and is justified by examples from simulations and experimental studies. Analysis to guarantee reliability of the method is not yet available.