bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium-Dependent Freezing Tolerance in Arabidopsis Involves Membrane Resealing via Synaptotagmin SYT1
Authors: Yamazaki Tomokazu , Kawamura Yukio , Minami Anzu , Uemura Matsuo
Published: December 2008

Plant freezing tolerance involves the prevention of lethal freeze-induced damage to the plasma membrane. We hypothesized that plant freezing tolerance involves membrane resealing, which, in animal cells, is accomplished by calcium-dependent exocytosis following mechanical disruption of the plasma membrane. In Arabidopsis thaliana protoplasts, extracellular calcium enhanced not only freezing tolerance but also tolerance to electroporation, which typically punctures the plasma membrane. However, calcium did not enhance survival when protoplasts were exposed to osmotic stress that mimicked freeze-induced dehydration. Calcium-dependent freezing tolerance was also detected with leaf sections in which ice crystals intruded into tissues. Interestingly, calcium-dependent freezing tolerance was inhibited by extracellular addition of an antibody against the cytosolic region of SYT1, a homolog of synaptotagmin known to be a calcium sensor that initiates exocytosis. This inhibition indicates that the puncture allowing the antibody to flow into the cytoplasm occurs during freeze/thawing. Thus, we propose that calcium-dependent freezing tolerance results from resealing of the punctured site. Protoplasts or leaf sections isolated from Arabidopsis SYT1-RNA interference (RNAi) plants lost calcium-dependent freezing tolerance, and intact SYT1-RNAi plants had lower freezing tolerance than control plants. Taken together, these findings suggest that calcium-dependent freezing tolerance results from membrane resealing and that this mechanism involves SYT1 function.
Efficacy of a self‐study programme to teach spiritual care
Authors: Taylor Elizabeth Johnston , Mamier Iris , Bahjri Khaled , Anton Triin , Petersen Floyd
Published: December 2008

Aim and objectives.  This study investigated the efficacy of a self study programme designed to teach nurses about how to talk with patients about spirituality, and to identify factors predicting this learning. Furthermore, the study investigated whether there were differences in learning between students and practicing clinicians, and between those in a religious or non‐religious institution.

Background.  Although USA and UK accrediting bodies mandate nurses learn how to assess and support patient spiritual health, there is a paucity of evidence to guide educators regarding how to teach spiritual care to nurses. Indeed, it is unknown if aspects of spiritual care can be taught using formal approaches.

Design.  A pretest‐posttest pre‐experimental design was used to study how attitude toward spiritual care, ability to create empathic verbal responses to expressed spiritual pain, personal spiritual experience, and knowledge about communication for spiritual caregiving changed from before to after programme completion.

Methods.  Study participants, 201 nursing students and RNs, independently completed the mailed self‐study programme (i.e. workbook with supplemental DVD) and self‐report study instruments (i.e. Daily Spiritual Experience Scale, Spiritual Care Perspective Scale‐Revised, Response Empathy Scale, Communicating for Spiritual Care Test, and Information about You form).

Results.  Significant differences were seen between the before and after scores measuring attitude, ability, spiritual experience, and knowledge. An interaction effect of time between students and registered nurses for both spiritual care attitude and personal spiritual experience was observed.

Conclusions.  Findings suggest learning occurred for both students and RNs, regardless of whether they were at a religious institution or not.

Relevance to clinical practice.  These data indicate that this self‐study programme was an effective approach to teach nurses about how to converse with patients about spirituality.
Effectiveness of magnetic resonance angiography in the evaluation of lung perfusion in constrictive bronchiolitis obliterans
Authors: YILMAZ ÖZge , SAVAŞ Recep , SOGUT Ayhan , ÖZKOL Mine , YÜKSEL Hasan
Published: December 2008

Childhood constrictive bronchiolitis obliterans (CBO) is characterized clinically by the persistence of obstructive respiratory symptoms following a prolonged episode of lower respiratory viral infection. The diagnosis depends on the clinical, radiological and laboratory findings. Perfusion defects on scintigraphy may predict the severity. This report describes a 2‐year‐old girl who presented with a 15‐day history of respiratory distress despite treatment. Auscultation of the lungs revealed prolonged expiration and bilateral crepitant rales. CXR revealed bilateral paracardiac infiltration. She improved with a treatment regimen of bronchodilators, systemic steroids and antibiotherapy; however, rales were detected again 10 days after discharge. HRCT of the lung revealed an oligaemic‐mosaic pattern, more prominent in the left lung. The diagnosis of CBO was made on the basis of these clinical and radiological findings. Perfusion was normal in the right lung but diffusely decreased in the left lung on perfusion scintigraphy by Tc99m‐MAA. Magnetic resonance (MR) angiography source images of the lungs revealed significant but not diffuse perfusion defects in the left lung, in contrast to radionuclide scintigraphy. There were areas of low perfusion in the right lung, which were not evident in radionuclide scintigraphy. The use of source images of MRI angiography of the lungs may be more sensitive and specific for the detection of perfusion defects in patients with CBO and may assist in determining the prognosis.
Platinum Group Metal Flows of Europe, Part 1
Authors: Saurat Mathieu , Bringezu Stefan
Published: December 2008

In this article, we analyze flows of the platinum group metals (PGMs) platinum, palladium, and rhodium and the environmental impacts associated with their supply in Europe. A model of the use of PGMs in Europe has been developed, and this is combined with a model of environmental pressures related to PGM production.

Seven industrial sectors and product groups form the main users of PGMs in Europe, comprising the chemical, petroleum, and glass industries; jewelry, dentistry, electronic equipment, and car catalysts. Most relevant environmental impacts of secondary production in Europe and primary PGM production in South Africa, Russia, and Canada are taken into account, including emissions of sulphur dioxide and carbon dioxide and total material requirement.

The article quantifies the PGM flows to, from, and within Europe in 2004. The automotive industry is the single largest user of primary PGMs, and catalytic converters represent the major PGM end use. The chemical and glass industries also require large amounts of PGM but rely mostly on secondary metals. The environmental impacts of primary production exceed those of secondary production by far. An analysis of the use of car catalytic converters shows that as a result of efforts to reduce air pollutant emissions in Europe, other negative environmental impacts, such as point‐source pollution and mining waste, are occurring elsewhere—for example, at extraction and refining sites in Siberia and South Africa.
The New Public Management theory and European health‐care reforms
Authors: Simonet Daniel
Published: December 2008

Abstract:This article analyses the dynamics of health‐care reforms in Germany, the U.K., Switzerland, France and Italy. In light of the “New Public Management” (NPM) theory, the author discusses governments' attempts at providing better health‐care services for less. Health‐care reforms inspired by NPM meant opening up to competition and revamping service provision to improve organizational performance. These reforms also put the emphasis on outcomes measurements to improve insurers and providers' accountability, demanded greater decentralization of the decision‐making process (e.g., planning, investment and financing of health‐care services), and encouraged contracting‐out of public services and partnerships between the public and the private sector. While most features of the NPM theory were applicable to EU health‐care reforms, NPM was not a panacea: it advanced at different paces across nations, with some aspects of NPM being more appropriate in some countries but less so in others. It led to greater inequity and more bureaucracy in some, but not all, countries. Competition, a major characteristic of the NPM, did not necessarily lead to better health outcomes, and, unlike in other sectors, the application of NPM in health care meant larger providers (e.g., insurers, hospitals) and regulations have remained strong.

Sommaire:Le présent article analyse la dynamique des réformes des soins de santé en Allemagne, au Royaume‐Uni, en Suisse, en France et en Italie. À la lumière de la théorie de la « Nouvelle administration publique » (NAP), l'auteur discute des tentatives menées par les gouvernements pour fournir de meilleurs services de soins de santéà un moindre coût. Les réformes des soins de santé inspirées par la NAP ont signifié l'ouverture à la concurrence et la réorganisation de la prestation des services pour améliorer la performance organisationnelle. Ces réformes ont également mis l'accent sur les mesures des résultats afin d'améliorer l'imputabilité des assureurs et des fournisseurs, ont exigé une plus grande décentralisation du processus de prise de décision (p. ex., planification, investissement, et financement des services de soins de santé), et ont encouragé la sous‐traitance des services publics et la formation de partenariats entre les secteurs public et privé. Alors que la plupart des éléments de la théorie de la NAP étaient applicables aux réformes des soins de santé de l'UE, la NAP n'a pas été la panacée : elle a progresséà des rythmes différents suivant les pays, certains aspects de la NAP étant plus appropriés dans certains pays que dans d'autres. Cela a entraîné une plus grande iniquité et plus de bureaucratie dans certains pays. La concurrence, une caractéristique importante de la NAP, n'a pas nécessairement entraîné de meilleurs résultats pour la santé et, à la différence d'autres secteurs, l'application de la NAP aux soins de santé a signifié de plus importants fournisseurs (p. ex., assureurs, hôpitaux) et le maintien de règlements solides.
Towards community‐based monitoring in Manitoba's hog industry
Authors: Moyer Joanne , Fitzpatrick Patricia , Diduck Alan , Froese Beverly
Published: December 2008

Abstract: Rapid changes in the hog industry in Manitoba have resulted in a gap in the province's resource and environmental policy regime. Concerns about potential, uncertain environmental impacts and an outdated regulatory framework led to a moratorium on new hog industry operations and a provincial hearing. Based on extensive literature, documentary and legislative reviews, this article explores the role of monitoring, and the potential for community‐based monitoring specifically, to address these policy issues. Given the non‐point nature of the pollution in question, the social and economic conditions in southern Manitoba and the strengths of community‐based monitoring initiatives, this approach is a promising solution. Furthermore, the existing legal framework provides an existing grounding through which the program could be vested with authority.

Sommaire: Des changements rapides dans l'industrie porcine au Manitoba ont entraîné un fossé entre la politique des ressources et celle de l'environnement de la province. Les inquiétudes au sujet d'éventuelles conséquences environnementales et d'un cadre de réglementation dépassé ont conduit à un moratoire sur les nouvelles opérations dans l'industrie porcine et à une audience provinciale. En s'appuyant sur une importante documentation et sur des études documentaires et législatives, cet article approfondit le rôle de la surveillance, et plus particulièrement le rôle possible de la surveillance communautaire, pour s'attaquer à ces questions de politiques. Étant donné la nature non ponctuelle de la pollution en question, les conditions sociales et économiques dans le sud du Manitoba et la force des initiatives communautaires, cette approche est une solution prometteuse. En outre, le cadre juridique actuel fournit une base existante qui permettrait au programme d'être investi d'une certaine autorité.
Development of Vehicle Dynamics Simulation for Safety Analyses of Rail Vehicles on Excited Tracks
Authors: Nishimura Kazuhiko , Terumichi Yoshiaki , Morimura Tsutomu , Sogabe Kiyoshi
Published: December 2008

Considerable numbers of earthquake disasters have been experienced in Japan. Thus the study and research of earthquake disaster prevention are highly aware in Japan. In a railway industry, for instance, infrastructures have been reinforced, and a new alert system has been employed to regulate the operating system to stop trains immediately if a great earthquake occurs. A railway is organized by a variety of individual technologies and functions safely and properly as a system; therefore it is beneficial for the system safety to study and examine the individual potential cases of disasters caused by earthquakes from various different viewpoints. Recent reports imply that rail vehicles could derail solely by the ground motions of earthquakes without fatal damages of vehicles and tracks. Therefore, in this paper, the vehicle safety in terms of the dynamic stability and the possibility of derailment directly caused by the track excitations of great earthquakes is specifically studied. The rail vehicles are supposed to involve severe vehicle body motions, wheel lifts, and derailing behaviors. In this study, such extreme responses of the vehicles are focused on; thus at the start, a new vehicle dynamics simulation is developed with unique modeling specifically taking account of internal slide forces between the vehicle body and the bogie resulting from large motions of vehicles. Then, the simulation is employed to assess the safety of vehicles on excited tracks with sinusoidal displacements, and the numerical results are analyzed. Through the assessment and the analyses, four major outcomes are obtained. First, the limit excitation amplitudes for the wheel lift of flange height, defined as safety limits in this paper, are presented in the frequency range of 0.5–2.5Hz. Second, two types of critical vehicle motions are captured; one is a rocking motion involving large wheel lift observed in lower frequency excitations and the other is a severe horizontal impact of a wheel to a rail observed in higher frequency excitations. In the latter cases, the vehicles derail with slightly larger excitations than those of the wheel lift of flange height. Third, the roll characteristic of a vehicle body is demonstrated as a dominant factor for the vehicle dynamic motions in terms of large wheel lift and derailment. Finally, the unique modeling in the developed simulation is evaluated, and its advantages for precise prediction of the extreme vehicle responses are confirmed.
A Jacobian-Based Algorithm for Planning Attitude Maneuvers Using Forward and Reverse Rotations
Authors: Koh Sung K. , Chirikjian Gregory S. , Ananthasuresh G. K.
Published: December 2008

Algorithms for planning quasistatic attitude maneuvers based on the Jacobian of the forward kinematic mapping of fully-reversed (FR) sequences of rotations are proposed in this paper. An FR sequence of rotations is a series of finite rotations that consists of initial rotations about the axes of a body-fixed coordinate frame and subsequent rotations that undo these initial rotations. Unlike the Jacobian of conventional systems such as a robot manipulator, the Jacobian of the system manipulated through FR rotations is a null matrix at the identity, which leads to a total breakdown of the traditional Jacobian formulation. Therefore, the Jacobian algorithm is reformulated and implemented so as to synthesize an FR sequence for a desired rotational displacement. The Jacobian-based algorithm presented in this paper identifies particular six-rotation FR sequences that synthesize desired orientations. We developed the single-step and the multiple-step Jacobian methods to accomplish a given task using six-rotation FR sequences. The single-step Jacobian method identifies a specific FR sequence for a given desired orientation and the multiple-step Jacobian algorithm synthesizes physically feasible FR rotations on an optimal path. A comparison with existing algorithms verifies the fast convergence ability of the Jacobian-based algorithm. Unlike closed-form solutions to the inverse kinematics problem, the Jacobian-based algorithm determines the most efficient FR sequence that yields a desired rotational displacement through a simple and inexpensive numerical calculation. The procedure presented here is useful for those motion planning problems wherein the Jacobian is singular or null.
Dependability-Based Design Optimization of Degrading Engineering Systems
Authors: Savage Gordon J. , Son Young Kap
Published: December 2008

In this paper, we present a methodology that helps select the distribution parameters in degrading multiresponse systems to improve dependability at the lowest lifetime cost. The dependability measures include both quality (soft failures) and reliability (hard failures). Associated costs of scrap, rework, and warrantee work are included. The key to the approach is the fast and efficient creation of the system cumulative distribution function through a series of time-variant limit-state functions. Probabilities are evaluated by Monte Carlo simulation although the first-order reliability method is a viable alternative. The cost objective function that is common in reliability-based design optimization is expanded to include a lifetime loss of performance cost, herein based on present worth theory (also called present value theory). An optimum design in terms of distribution parameters of the design variables is found via a methodology that involves minimizing cost under performance policy constraints over the lifetime as the system degrades. A case study of an over-run clutch provides the insights and potential of the proposed methodology.
A New Gerotor Design Method With Switch Angle Assignability
Authors: Yan Jia , Yang Daniel C. H. , Tong Shih-Hsi
Published: December 2008

Gerotor is generated by an oval shape generating curve, which is attached to a large pitch circle rolling on an inside smaller one. For gerotor design, existing methods are able to handle arc-based generating curves with switch angle assignability. However, when dealing with nonarc-based generating curves, the current methods do not provide switch angle assignability. The switch angle is an important parameter in gerotor kinematics; it determines the angular conjugating range on the generating curve and affects the rotor profile. In this paper, we developed a deviation-function-based design method. By using this method, users can design and directly assign switch angles to both arc- and nonarc-based gerotors. Analytical formulations of both generating and gerotor profiles are derived and summarized into a detailed algorithm in design steps. Some designed gerotor examples using our method are provided for design and process illustration.
Mine Impact Burial Prediction From One to Three Dimensions
Authors: Chu Peter C.
Published: December 2008

The Navy’s mine impact burial prediction model creates a time history of a cylindrical or a noncylindrical mine as it falls through air, water, and sediment. The output of the model is the predicted mine trajectory in air and water columns, burial depth/orientation in sediment, as well as height, area, and volume protruding. Model inputs consist of parameters of environment, mine characteristics, and initial release. This paper reviews near three decades’ effort on model development from one to three dimensions: (1) one-dimensional models predict the vertical position of the mine’s center of mass (COM) with the assumption of constant falling angle, (2) two-dimensional models predict the COM position in the (x,z) plane and the rotation around the y-axis, and (3) three-dimensional models predict the COM position in the (x,y,z) space and the rotation around the x-, y-, and z-axes. These models are verified using the data collected from mine impact burial experiments. The one-dimensional model only solves one momentum equation (in the z-direction). It cannot predict the mine trajectory and burial depth well. The two-dimensional model restricts the mine motion in the (x,z) plane (which requires motionless for the environmental fluids) and uses incorrect drag coefficients and inaccurate sediment dynamics. The prediction errors are large in the mine trajectory and burial depth prediction (six to ten times larger than the observed depth in sand bottom of the Monterey Bay). The three-dimensional model predicts the trajectory and burial depth relatively well for cylindrical, near-cylindrical mines, and operational mines such as Manta and Rockan mines.
A Survey With Numerical Assessment of Classical and Refined Theories for the Analysis of Sandwich Plates
Authors: Carrera E. , Brischetto S.
Published: December 2008

A large variety of plate theories are described and assessed in the present work to evaluate the bending and vibration of sandwich structures. A brief survey of available works is first given. Such a survey includes significant review papers and latest developments on sandwich structure modelings. The kinematics of classical, higher order, zigzag, layerwise, and mixed theories is described. An exhaustive numerical assessment of the whole theories is provided in the case of closed form solutions of simply supported panels made of orthotropic layers. Reference is made to the unified formulation that has recently been introduced by the first author for a plate/shell analysis. Attention has been given to displacements, stresses (both in-plane and out-of-plane components), and the free vibration response. Only simply supported orthotropic panels loaded by a transverse distribution of bisinusoidal pressure have been analyzed. Five benchmark problems are treated. The accuracy of the plate theories is established with respect to the length-to-thickness-ratio (LTR) geometrical parameters and to the face-to-core-stiffness-ratio (FCSR) mechanical parameters. Two main sources of error are outlined, which are related to LTR and FCSR, respectively. It has been concluded that higher order theories (HOTs) can be conveniently used to reduce the error due to LTR in thick plate cases. But HOTs are not effective in increasing the accuracy of the classical theory analysis whenever the error is caused by increasing FCSR values; layerwise analysis becomes mandatory in this case.
Linking Sequence to Function in Soil Bacteria: Sequence-Directed Isolation of Novel Bacteria Contributing to Soilborne Plant Disease Suppression
Authors: Benítez María-Soledad , McSpadden Gardener Brian B.
Published: December 2008

Microbial community profiling of samples differing in a specific ecological function, i.e., soilborne plant disease suppression, can be used to mark, recover, and ultimately identify the bacteria responsible for that specific function. Previously, several terminal restriction fragments (TRF) of 16S rRNA genes were statistically associated with damping-off disease suppression. This work presents the development of sequence-based TRF length polymorphism (T-RFLP)-derived molecular markers to direct the identification and isolation of novel bacteria involved in damping-off pathogen suppression. Multiple sequences matching TRF M139 and M141 were cloned and displayed identity to multiple database entries in the genera incertae sedis of the
Burkholderiales
. Sequences matching TRF M148, in contrast, displayed greater sequence diversity. A sequence-directed culturing strategy was developed using M139- and M141-derived markers and media reported to be selective for the genera identified within this group. Using this approach, we isolated and identified novel
Mitsuaria
and
Burkholderia
species with high levels of sequence similarity to the targeted M139 and M141 TRF, respectively. As predicted, these
Mitsuaria
and
Burkholderia
isolates displayed the targeted function by reducing fungal and oomycete plant pathogen growth in vitro and reducing disease severity in infected tomato and soybean seedlings. This work represents the first successful example of the use of T-RFLP-derived markers to direct the isolation of microbes with pathogen-suppressing activities, and it establishes the power of low-cost molecular screening to identify and direct the recovery of functionally important microbes, such as these novel biocontrol strains.
A Chromosomally LocatedtraHIJKCLMNOperon Encoding a Putative Type IV Secretion System Is Involved in the Virulence ofYersinia ruckeri
Authors: Méndez J. , Fernández L. , Menéndez A. , Reimundo P. , Pérez-Pascual D. , Navais R. , Guijarro J. A.
Published: December 2008

Nucleotide sequence analysis of the region surrounding the pIVET8 insertion site inYersinia ruckeri150RiviXII, previously selected by in vivo expression technology (IVET), revealed the presence of eight genes (traHIJKCLMN[hereafter referred to collectively as thetraoperon ortracluster]), which are similar both in sequence and organization to thetraoperon cluster found in the virulence-related plasmid pADAP fromSerratia entomophila. Interestingly, thetracluster ofY. ruckeriis chromosomally encoded, and no similartracluster has been identified yet in the genomic analysis of human pathogenic yersiniae. AtraIinsertional mutant was obtained by homologous recombination. Coinfection experiments with the mutant and the parental strain, as well as 50% lethal dose determinations, indicate that this operon is involved in the virulence of this bacterium. All of these results suggest the implication of thetracluster in a virulence-related type IV secretion/transfer system. Reverse transcriptase PCR studies showed that this cluster is transcribed as an operon from a putative promoter located upstream oftraHand that the mutation oftraIhad a polar effect. AtraI::lacZYtranscriptional fusion displayed higher expression levels at 18°C, the temperature of occurrence of the disease, and under nutrient-limiting conditions. PCR detection analysis indicated that thetracluster is present in 15Y. ruckeristrains from different origins and with different plasmid profiles. The results obtained in the present study support the conclusion, already suggested by different authors, thatY. ruckeriis a very homogeneous species that is quite different from the other members of the genusYersinia.
Taxonomic Structure and Monitoring of the Dominant Population of Lactic Acid Bacteria during Wheat Flour Sourdough Type I Propagation Using
Lactobacillus sanfranciscensis
Starters
Authors: Siragusa Sonya , Di Cagno Raffaella , Ercolini Danilo , Minervini Fabio , Gobbetti Marco , De Angelis Maria
Published: December 2008

The structure and stability of the dominant lactic acid bacterium population were assessed during wheat flour sourdough type I propagation by using singly nine strains of
Lactobacillus sanfranciscensis
. Under back-slopping propagation with wheat flour type 0 F114, cell numbers of presumptive lactic acid bacteria varied slightly between and within starters. As determined by randomly amplified polymorphic DNA-PCR and restriction endonuclease analysis-pulsed-field gel electrophoresis analyses, only three (LS8, LS14, and LS44) starters dominated throughout 10 days of propagation. The others progressively decreased to less than 3 log CFU g
−1
. Partial sequence analysis of the 16S rRNA and
recA
genes and PCR-denaturating gradient gel electrophoresis analysis using the
rpoB
gene allowed identification of
Weissella confusa
,
Lactobacillus sanfranciscensis
,
Lactobacillus plantarum
,
Lactobacillus rossiae
,
Lactobacillus brevis
,
Lactococcus lactis
subsp.
lactis
,
Pediococcus pentosaceus
, and
Lactobacillus
spp. as the dominant species of the raw wheat flour. At the end of propagation, one autochthonous strain of
L. sanfranciscensis
was found in all the sourdoughs. Except for
L. brevis
, strains of the above species were variously found in the mature sourdoughs. Persistent starters were found in association with other biotypes of
L. sanfranciscensis
and with
W. confusa
or
L. plantarum
. Sourdoughs were characterized for acidification, quotient of fermentation, free amino acids, and community-level catabolic profiles by USING Biolog 96-well Eco microplates. In particular, catabolic profiles of sourdoughs containing persistent starters behaved similarly and were clearly differentiated from the others. The three persistent starters were further used for the production of sourdoughs and propagated by using another wheat flour whose lactic acid bacterium population in part differed from the previous one. Also, in this case all three starter strains persisted during propagation.
An Orphan LuxR Homolog of
Sinorhizobium meliloti
Affects Stress Adaptation and Competition for Nodulation
Authors: Patankar Arati V. , González Juan E.
Published: December 2008

The Sin/ExpR quorum-sensing system of
Sinorhizobium meliloti
plays an important role in the symbiotic association with its host plant,
Medicago sativa
. The LuxR-type response regulators of the Sin system include the synthase (SinI)-associated SinR and the orphan regulator ExpR. Interestingly, the
S. meliloti
Rm1021 genome codes for four additional putative orphan LuxR homologs whose regulatory roles remain to be identified. These response regulators contain the characteristic domains of the LuxR family of proteins, which include an N-terminal autoinducer/response regulatory domain and a C-terminal helix-turn-helix domain. This study elucidates the regulatory role of one of the orphan LuxR-type response regulators, NesR. Through expression and phenotypic analyses,
nesR
was determined to affect the active methyl cycle of
S. meliloti
. Moreover,
nesR
was shown to influence nutritional and stress response activities in
S. meliloti
. Finally, the
nesR
mutant was deficient in competing with the wild-type strain for plant nodulation. Taken together, these results suggest that NesR potentially contributes to the adaptability of
S. meliloti
when it encounters challenges such as high osmolarity, nutrient starvation, and/or competition for nodulation, thus increasing its chances for survival in the stressful rhizosphere.
Identification of Freshwater
Phycodnaviridae
and Their Potential Phytoplankton Hosts, Using DNA
pol
Sequence Fragments and a Genetic-Distance Analysis
Authors: Clasen Jessica L. , Suttle Curtis A.
Published: December 2008

Viruses that infect phytoplankton are an important component of aquatic ecosystems, yet in lakes they remain largely unstudied. In order to investigate viruses (
Phycodnaviridae
) infecting eukaryotic phytoplankton in lakes and to estimate the number of potential host species, samples were collected from four lakes at the Experimental Lakes Area in Ontario, Canada, during the ice-free period (mid-May to mid-October) of 2004. From each lake,
Phycodnaviridae
DNA polymerase (
pol
) gene fragments were amplified using algal-virus-specific primers and separated by denaturing gradient gel electrophoresis; 20 bands were extracted from the gels and sequenced. Phylogenetic analysis indicated that freshwater environmental phycodnavirus sequences belong to distinct phylogenetic groups. An analysis of the genetic distances “within” and “between” monophyletic groups of phycodnavirus isolates indicated that DNA
pol
sequences that differed by more than 7% at the inferred amino acid level were from viruses that infect different host species. Application of this threshold to phylogenies of environmental sequences indicated that the DNA
pol
sequences from these lakes came from viruses that infect at least nine different phytoplankton species. A multivariate statistical analysis suggested that potential freshwater hosts included
Mallomonas
sp.,
Monoraphidium
sp., and
Cyclotella
sp. This approach should help to unravel the relationships between viruses in the environment and the phytoplankton hosts they infect.
Role of Germinant Receptors in Caco-2 Cell-Initiated Germination of
Bacillus cereus
ATCC 14579 Endospores
Authors: Hornstra Luc M. , van der Voort Menno , Wijnands Lucas M. , Roubos-van den Hil Petra J. , Abee Tjakko
Published: December 2008

Spores obtained from
Bacillus cereus
ATCC 14579 and mutant strains lacking each of seven germinant receptor operons were exposed to differentiated Caco-2 cells and monitored for germination. Spores of the
gerI
and
gerL
mutants showed a reduced germination response, pointing to a role for these receptors in Caco-2-induced germination.
l
-Valine Production during Growth of Pyruvate Dehydrogenase Complex- Deficient
Corynebacterium glutamicum
in the Presence of Ethanol or by Inactivation of the Transcriptional Regulator SugR
Authors: Blombach Bastian , Arndt Annette , Auchter Marc , Eikmanns Bernhard J.
Published: December 2008

Pyruvate dehydrogenase complex-deficient strains of
Corynebacterium glutamicum
produce
l
-valine from glucose only after depletion of the acetate required for growth. Here we show that inactivation of the DeoR-type transcriptional regulator SugR or replacement of acetate by ethanol already in course of the growth phase results in efficient
l
-valine production.
Molecular Ecological Analysis of Fecal Bacterial Populations from Term Infants Fed Formula Supplemented with Selected Blends of Prebiotics
Authors: Nakamura Noriko , Gaskins H. Rex , Collier Chad T. , Nava Gerardo M. , Rai Deshanie , Petschow Bryon , Russell W. Michael , Harris Cheryl , Mackie Roderick I. , Wampler Jennifer L. , Walker D. Carey
Published: December 2008

Supplementation of infant formulas with prebiotic ingredients continues the effort to mimic functional properties of human milk. In this double-blind, controlled, 28-day study, healthy term infants received control formula (control group;
n
= 25) or control formula supplemented with polydextrose (PDX) and galactooligosaccharide (GOS) (4 g/liter) (PG4 group;
n
= 27) or with PDX, GOS, and lactulose (LOS) (either 4 g/liter [PGL4 group;
n
= 27] or 8 g/liter [PGL8 group;
n
= 25]). A parallel breast-fed group (BF group) (
n
= 30) was included. Stool characteristics, formula tolerance, and adverse events were monitored. Fecal bacterial subpopulations were evaluated by culture-based selective enumeration (
Enterobacteriaceae
), quantitative real-time PCR (
Clostridium
clusters I, XI, and XIV,
Lactobacillus
, and
Bifidobacterium
), and fluorescence in situ hybridization (FISH) (
Bifidobacterium
). Fecal bacterial community profiles were examined by using 16S rRNA gene PCR-denaturing gradient gel electrophoresis. The daily stool consistency was significantly softer or looser in the BF group than in all of the groups that received formula. The formulas were well tolerated, and the incidences of adverse events did not differ among feeding groups. Few significant changes in bacterial subpopulations were observed at any time point. The bacterial communities were stable; individual profiles tended to cluster by subject rather than by group. Post hoc analysis, however, demonstrated that the bacterial community profiles for subjects in the BF, PG4, PGL4, and PGL8 groups that first received formula at a younger age were less stable than the profiles for subjects in the same groups that received formula at an older age, but there was no difference for the control group. These data indicate that formulas containing PDX, GOS, and LOS blends are more likely to influence gut microbes when administration is begun in early infancy and justify further investigation of the age-related effects of these blends on fecal microbiota.
Cancer of the respiratory tract in nickel sinter plant workers: effect of removal from sinter plant exposure.
Authors: Muir D C , Jadon N , Julian J A , Roberts R S
Published: December 2008

The risk of death due to cancer of the nose or lung was studied in nickel sinter plant workers during the period after they left the sintering operations. It was found that the excess risk of death from both diseases continued for many years after leaving the sinter plant. No effect of age at first exposure could be found. Possible explanations for the continued risk include an irreversible cellular change or the persistence of carcinogenic nickel compounds in the mucosa.
Analysis of chromosomal aberrations in shoe workers exposed long term to benzene.
Authors: Türkel B , Egeli U
Published: December 2008

Cytogenetic analysis of peripheral blood lymphocytes was used to compare 58 shoe workers (57 men and one woman) exposed to benzene and 20 subjects selected from the general population not exposed to particular mutagenic or carcinogenic agents (control group). Frequencies of damaged cells, including gaps, breaks, and rearrangements (acentric fragment, deletion, translocation) were scored for both groups. The incidence of chromosomal aberrations (particularly chromatid gaps and breaks) in the exposed group was significantly higher than in the control group. There were no effects of smoking and only breaks were affected by alcohol. Nor was there a significant relation between the working period in the group exposed to benzene and frequency of chromosomal aberrations.
Clinical reactions to Aspergillus niger in a biotechnology plant: an eight year follow up.
Authors: Seaton A , Wales D
Published: December 2008

The manufacture of citric acid by fermentation of molasses with Aspergillus niger has previously been described as a cause of occupational asthma in a factory. A longitudinal survey of the workforce of this factory has been carried out from 1984 to 1991. Over this period 160 of the original 278 workers left the workforce, together with 39 of 76 new recruits. Partial enclosure of the process and exhaust ventilation, installed in 1984, was effective in preventing any new cases of occupational asthma over the eight year period, and no new skin sensitisation was detected. Spore counts of A niger averaged about 100 times those in the outside air. Health in the 1984 survey had a striking influence on subsequent retiral; only 11 of the 79 with respiratory symptoms remained in 1991, compared with 90 of the 182 with no symptoms. In conclusion A niger is a weak antigen and simple hygiene measures protect the workforce. Exclusion of recruits with positive skin tests is not necessary if such measures are taken. The survey provided evidence of the selection factors operating within a workforce over this period contributing to retiral of the less healthy.
Partition coefficients of some acetate esters and alcohols in water, blood, olive oil, and rat tissues.
Authors: Kaneko T , Wang P Y , Sato A
Published: December 2008

Partition coefficients of hydrophilic organic solvents (C1-C5 acetate esters and alcohols) in distilled water, olive oil, human blood, and various rat tissues (blood, liver, kidney, brain, muscle, and fat) were determined. Water/air partition coefficients were measured by a new vial equilibration technique, which needs no direct measurement of the concentration in either the liquid phase or the gas phase, but only the gas chromatographic peak areas from both phases. Once the water/air partition coefficients had been measured, the blood/air, oil/air, and tissue/air partition coefficients could be measured by the previously developed vial equilibration method, which uses gas chromatographic peak areas from the gas phases in the sample (which contains test material) and the reference (which contains no test material) vessels. The alcohols tested were 32 (methanol) to 128 (n-pentanol) times more hydrophilic than the corresponding esters compared with oil/water partition coefficients. In general, water/air partition coefficients decreased and oil/air partition coefficients increased in proportion to the number of carbon atoms. Blood/air coefficients of alcohols were almost parallel to water/air partition coefficients, whereas no such relation was found with acetate esters. n-Isomers of both acetate esters and alcohols were found to be more soluble in water, blood, oil, and tissues than the corresponding iso-isomers.
Survey of methods and statistical models used in the analysis of occupational cohort studies.
Authors: Callas P W , Pastides H , Hosmer D W
Published: December 2008

OBJECTIVES--This survey was conducted to determine the frequency with which different data analysis techniques are being used in occupational cohort studies. Of particular interest was the relative use of external and internal comparison groups, and the choice of multivariable model. METHODS--Occupational cohort studies published in 1990-91 were located with Medline and Index Medicus, and the contents of several relevant journals were systematically reviewed. Each study was categorised by the methods of external or internal comparisons performed. RESULTS--Of 200 occupational cohort studies identified, 104 (52%) conducted only external comparisons, 46 (23%) conducted only internal, and 50 (25%) presented both. Of those that used an external referent population, about two thirds used a national standard. 40 of the studies that performed internal comparisons fitted multivariable models, with use divided about equally between proportional hazards regression, Poisson regression, and logistic regression. DISCUSSION--The finding that logistic regression is used quite commonly, even though it does not directly model time dependent data of the type frequently encountered in occupational cohort studies, was suprising. The reasons why investigators choose from among the available statistical and modelling techniques are likely to include familiarity, ease of use, restrictions in study population characteristics, especially study size, and others. Authors should be encouraged to be more explicit about the statistical methods used in the analysis of occupational cohort studies, as well as whether important assumptions about their data have been evaluated.
Dental health in workers previously exposed to mercury vapour at a chloralkali plant.
Authors: Holland R I , Ellingsen D G , Olstad M L , Kjuus H
Published: December 2008

OBJECTIVES--The dental health of 73 workers previously exposed to mercury vapour at a chloralkali plant was studied and compared with that of 51 non-exposed referents. METHODS--A record of oral, periodontal, gingival and mucosal conditions, including teeth, restorations, prostheses, and oral hygiene, was established during a 30 min examination. The participants' periodontal conditions were assessed according to the community periodontal index of treatment needs (CPITN). The results with the CPITN index were also compared with previously published data for another similar population. RESULTS--There was no significant difference between the exposed workers and the referents with respect to the number of remaining teeth, amount of amalgam restorations, crowns, bridges, or endodontically treated teeth. The oral hygiene among the exposed workers was significantly better than among the referents, but the periodontal health conditions did not significantly differ between the two groups, nor from those of another Norwegian population. DISCUSSION--The present results seem to contradict previous reports claiming tooth loss as a possible result of exposure to mercury vapour.
Use of molecular epidemiological techniques in a pilot study on workers exposed to chromium.
Authors: Gao M , Levy L S , Faux S P , Aw T C , Braithwaite R A , Brown S S
Published: December 2008

OBJECTIVES--Molecular epidemiological techniques, capable of detecting damage to DNA, were used to see if such damage occurred in the lymphocytes of a group of workers exposed to chromium. The two aims of this pilot study were to see if these new techniques might make useful biological monitoring tools for workers exposed to chromium and also, to help assess whether the current occupational exposure limit for chromium (VI) was sufficiently protective in this specific working situation. METHODS--Volunteer groups of 10 workers exposed to chromium and 10 non-exposed workers provided urine and blood samples towards the end of the working week. Chromium concentrations were measured in whole blood, plasma, lymphocytes, and urine. Lymphocytes were used to examine two forms of DNA damage in the two groups; these were the level of DNA strand breakage and, the production of 8-hydroxydeoxyguanosine. RESULTS--Chromium concentration in whole blood, plasma, and urine of workers exposed to chromium was significantly raised (P < 0.01) compared with non-exposed controls, but in isolated lymphocytes, there was only a modest but significant (P < 0.05) increase in chromium in the group exposed to chromium. There was no difference in the levels of DNA strand breaks or 8-hydroxydeoxyguanosine between the groups. Air monitoring for chromium was not undertaken but current levels for the group exposed to chromium were reported to be around 0.01 mg/m3, which is 20% of the current United Kingdom occupational exposure limit. CONCLUSIONS--We were unable to detect any damage in lymphocytic DNA due to exposure to chromium. This may have been due to the low chromium exposure (< 20% of the United Kingdom occupational exposure limit), the ability of plasma to detoxify chromium (VI) to chromium (III) before it reached the lymphocytes, or perhaps the insensitivity of the molecular techniques used. It is now important to test these and other such techniques on groups exposed to levels closer to the United Kingdom occupational exposure limit.
Comparison of measures of lead exposure, dose, and chelatable lead burden after provocative chelation in organolead workers.
Authors: Schwartz B S , McGrail M P , Stewart W , Pluth T
Published: December 2008

OBJECTIVES--To describe 6 h urinary lead excretion (6 h PbU) after 1 g intravenous ethylene diamine tetraacetic acid (EDTA) in organolead manufacturing workers with mixed exposure to organic and inorganic lead; to determine the predictors of lead excretion (PbU); and to determine the extent to which internal lead stores and ongoing external exposure govern blood concentrations of lead (PbB). METHODS--A case series of 21 active workers were studied. Personal industrial hygiene data, grouped by 29 exposure zones, in combination with personal interviews about work location and times were used to derive several measures of recent and cumulative exposure to organic and inorganic lead. The average exposure intensities assigned to the 29 zones ranged from 4 to 119 micrograms/m3 (0.02-0.57 mumol/m3 as lead) for organic lead and from 1 to 56 micrograms/m3 (0.004-0.27 mumol/m3) for inorganic lead. RESULTS--After controlling for age, 6 h PbU was significantly and positively correlated with summary measures of PbB--for example, lifetime peak PbB, time weighted PbB--and zinc protoporphyrin concentrations--for example, lifetime peak zinc protoporphyrin, time weighted zinc protoporphyrin--but not with measures of estimated external exposure--for example, duration of exposure and cumulative exposure to inorganic or organic lead. Among workers with higher chelatable lead burdens (6 h PbU > or = 212.4 micrograms (1.03 mumol) divided at the median), there was no apparent relation between recent inorganic lead exposure and PbB at the time of chelation. Among workers with lower chelatable lead burdens (6 h PbU < 212.4 micrograms (1.03 mumol) however, there was a significant relation between exposure and effect between recent exposure to inorganic lead and PbBs. CONCLUSION--These findings are consistent with the concept of physiological dampening. The high chelatable lead burden, a source of internal exposure, dampens the effect of external exposure on PbBs. The data suggest that in organolead workers with high chelatable lead burdens, PbBs may be more influenced by internal lead stores than by variations in airborne exposure to organic and inorganic lead.