bluuebunny/crossref_metadata_2025 huggingface dataset:
Microfabrication of the Split and Recombination Micromixer and the Effect of Its Cross-Sectional Rotation
Authors: Lee Seok Woo , Lee Seung S.
Published: May 2009

This paper shows the microfabrication process of a split and recombination (SAR) micromixer and the effect of the cross-sectional rotation of fluidic interfaces, which is based on three dimensional microchannels composed of two poly-dimethysiloxane (PDMS) layers. When fluids pass through the nth SAR mixing unit, the number of interfaces increases to 2n+1−1 through SAR mixing. The cross-sectional rotation of interfaces induced by the different time of expanding at slanted walls enhances mixing efficiency. The effect of the rotation is compared by three types of the SAR micromixer characterized by the existence and the direction of the rotation. The first type, No-R type, has flat walls which do not induce the rotation. The second type, Co-R type, has slanted walls which induce counter-clockwise rotations. The third type, Count-R type, has slanted walls and the counter-clockwise rotation alternates with the clockwise rotation. Water and blue dye is used in the mixing experiment as mixing fluids. Each inlet’s flow rate range is between 1 μl/min (Re0.1179) and 100 μl/min (Re 11.79). In No-R type, there is a clear contrast in interfaces which means that there is no rotation effect in SAR mixing process. In Co-R and Count-R, the contrast is unclear because of the rotation. Mixing in the SAR micromixer is almost complete after the 7th unit, whose length is 4200μm. The performance of the micromixer is estimated by numerical analysis using CFD ACE+. The flow rate and the diffusion coefficient are set 5 μl/min (ReO.5893) and 10−10m2/s, respectively for each inlet. The cross-sectional view of simulational SAR mixing agrees with experimental observations. The simulation estimates that the degree of mixing is more than 90% after the 6th unit of the No-R and Co-R type SAR micromixer.
Evaluation of Continuum Mechanics for Electroosmotic Flow in Nanosize Structures
Authors: Taylor Jay , Ren Carolyn L.
Published: May 2009

Development of nano-devices for various applications has drawn great attention recently driven by the need of miniaturizing the devices for the integration and automation of Biochips or Lab-on-a-Chip devices. Fundamental understanding of transport phenomena in nanofluidic channels is critical for systematic design and precise control of such devices. The goal of this study is to develop a theoretical model to study electroosmotic flow in nanochannels. Instead of using the Boltzmann distribution, the conservation condition of ion number and the Nernst equation are used in this new model to find the ionic concentration field in the nanochannels. A correct boundary condition for the concentration field at the wall of the channel is developed and the symmetry condition of the potential field at the center of the nanochannel is applied to this model. The ionic concentration field, electrical potential field and flow field are obtained by numerically solving this model. Comparisons of area-average velocity between the numerical simulations and experimental results reported in literature are provided.
Inertia Driven Dispersion Between Patterned Surfaces
Authors: Assemat P. , Bergeon A. , Plouraboue´ F.
Published: May 2009

Understanding and controlling stirring in micro-systems is necessary for the design of efficient passive micro-mixer. In this study, we focus on the dispersion of passive tracers injected in flows in between two rough surfaces under weak inertia influence (small but non-zero Reynolds number). The flow is induced by a constant applied pressure gradient between two cross-sections of the channel and the velocity field is calculated thanks to an extension of the lubrication approximation taking into account the first order inertial corrections. Tracers trajectories are obtained by integrating numerically the quasi-analytic velocity field. Our purpose is to examine the flow structure for various surface patterns and various Reynolds number. We focus on a simplified aperture field which is a smooth periodic function. This study puts forward interesting behavior of streamlines and show the dispersion of passive tracers in various geometries.
On‐the‐fly motion‐compensated cone‐beam CT using an a priori model of the respiratory motion
Authors: Rit Simon , Wolthaus Jochem W. H. , van Herk Marcel , Sonke Jan‐Jakob
Published: May 2009

Respiratory motion causes artifacts in cone‐beam (CB) CT images acquired on slow rotating scanners integrated with linear accelerators. Respiration‐correlated CBCT has been proposed to correct for the respiratory motion but only a subset of the CB projections is used to reconstruct each frame of the 4D CBCT image and, therefore, adequate image quality requires long acquisition times. In this article, the authors develop an on‐the‐fly solution to estimate and compensate for the respiratory motion in the reconstruction of a 3D CBCT image from all the CB projections. An a priori motion model of the patient respiratory cycle is estimated from the 4D planning CT. During the acquisition, the model is correlated with the respiration using a respiratory signal extracted from the CB projections. The estimated motion is next compensated for in an optimized reconstruction algorithm. The motion compensated for is forced to be null on average over the acquisition time to ensure that the compensation results in a CBCT image which describes the mean position of each organ, even if the a priori motion model is inaccurate. Results were assessed on simulated, phantom, and patient data. In all experiments, blur was visually reduced by motion‐compensated CBCT. Simulations showed robustness to inaccuracies of the motion model observed on patient data such as amplitude variations, phase shifts, and setup errors, thus proving the efficiency of the compensation using an a priori motion model. Noise and view‐aliasing artifacts were lower on motion‐compensated CBCT images with 1 min scan than on respiration‐correlated CBCT images with 4 min scan. Finally, on‐the‐fly motion estimation and motion‐compensated reconstruction were within the acquisition time of the CB projections and the CBCT image available a few seconds after the end of the acquisition. In conclusion, the authors developed and implemented a method for correcting the respiratory motion during the treatment fractions which can replace respiration‐correlated CBCT for improving image quality while decreasing acquisition time.
Evaluation of a variable dose acquisition technique for microcalcification and mass detection in digital breast tomosynthesis
Authors: Das Mini , Gifford Howard C. , o'connor J. Michael , Glick Stephen J.
Published: May 2009

In this article the authors evaluate a recently proposed variable dose (VD)‐digital breast tomosynthesis (DBT) acquisition technique in terms of the detection accuracy for breast masses and microcalcification (MC) clusters. With this technique, approximately half of the total dose is used for one center projection and the remaining dose is split among the other tomosynthesis projection views. This acquisition method would yield both a projection view and a reconstruction view. One of the aims of this study was to evaluate whether the center projection alone of the VD acquisition can provide equal or superior MC detection in comparison to the 3D images from uniform dose (UD)‐DBT. Another aim was to compare the mass‐detection capabilities of 3D reconstructions from VD‐DBT and UD‐DBT. In a localization receiver operating characteristic (LROC) observer study of MC detection, the authors compared the center projection of a VD acquisition scheme (at dose) with detector pixel size of with the UD‐DBT reconstruction (at dose) obtained with a voxel size of . MCs with sizes of 150 and were used in the study, with each cluster consisting of seven MCs distributed randomly within a small volume. Reconstructed images in UD‐DBT were obtained from a projection set that had a total of dose. The current study shows that for MC detection, using the center projection alone of VD acquisition scheme performs worse with area under the LROC curve of 0.76 than when using the 3D reconstructed image using the UD acquisition scheme . A 2D ANOVA found a statistically significant difference at a significance level of 0.05. In the current study, although a reconstructed image was also available using the VD acquisition scheme, it was not used to assist the MC detection task which was done using the center projection alone. In the case of evaluation of detection accuracy of masses, the reconstruction with VD‐DBT was compared to that obtained from the UD‐DBT . The authors found no statistically significant difference between the two , although all the observers performed better for UD‐DBT.
Tomosynthesis imaging: At a translational crossroads
Authors: Dobbins James T.
Published: May 2009

Tomosynthesis is a decades‐old technique for section imaging that has seen a recent upsurge in interest due to its promise to provide three‐dimensional information at lower dose and potentially lower cost than CT in certain clinical imaging situations. This renewed interest in tomosynthesis began in the late 1990s as a new generation of flat‐panel detectors became available; these detectors were the one missing piece of the picture that had kept tomosynthesis from enjoying significant utilization earlier. In the past decade, tomosynthesis imaging has been investigated in a variety of clinical imaging situations, but the two most prominent have been in breast and chest imaging. Tomosynthesis has the potential to substantially change the way in which breast cancer and pulmonary nodules are detected and managed. Commercial tomosynthesis devices are now available or on the horizon. Many of the remaining research activities with tomosynthesis will be translational in nature and will involve physicist and clinician alike. This overview article provides a forward‐looking assessment of the translational questions facing tomosynthesis imaging and anticipates some of the likely research and clinical activities in the next five years.
First MR images obtained during megavoltage photon irradiation from a prototype integrated linac‐MR system
Authors: Fallone B. G. , Murray B. , Rathee S. , Stanescu T. , Steciw S. , Vidakovic S. , Blosser E. , Tymofichuk D.
Published: May 2009

The authors report the first magnetic resonance (MR) images produced by their prototype MR system integrated with a radiation therapy source. The prototype consists of a 6 MV linac mounted onto the open end of a biplanar 0.2 T permanent MR system which has 27.9 cm pole‐to‐pole opening with flat gradients (40 mT/m) running under a TMX NRC console. The distance from the magnet isocenter to the linac target is 80 cm. The authors’ design has resolved the mutual interferences between the two devices such that the MR magnetic field does not interfere with the trajectory of the electron in the linac waveguide, and the radiofrequency (RF) signals from each system do not interfere with the operation of the other system. Magnetic and RF shielding calculations were performed and confirmed with appropriate measurements. The prototype is currently on a fixed gantry; however, in the very near future, the linac and MR magnet will rotate in unison such that the linac is always aimed through the opening in the biplanar magnet. MR imaging was found to be fully operational during linac irradiation and proven by imaging a phantom with conventional gradient echo sequences. Except for small changes in SNR, MR images produced during irradiation were visually and quantitatively very similar to those taken with the linac turned off. This prototype system provides proof of concept that the design has decreased the mutual interferences sufficiently to allow the development of real‐time MR‐guided radiotherapy. Low field‐strength systems (0.2–0.5 T) have been used clinically as diagnostic tools. The task of the linac‐MR system is, however, to provide MR guidance to the radiotherapy beam. Therefore, the 0.2 T field strength would provide adequate image quality for this purpose and, with the addition of fast imaging techniques, has the potential to provide 4D soft‐tissue visualization not presently available in image‐guided radiotherapy systems. The authors’ initial design incorporates a permanent magnet; however, other types of magnets and field strengths could also be incorporated. Usable MR images were obtained during linac irradiation from the linac‐MR prototype. The authors’ prototype design can be used as the functional starting point in developing real‐time MR guidance offering soft‐tissue contrast that can be coupled with tumor tracking for real‐time adaptive radiotherapy.
Essential Role of the Glycosyltransferase Sxc/Ogt in Polycomb Repression
Authors: Gambetta Maria Cristina , Oktaba Katarzyna , Müller Jürg
Published: May 2009

Putting the Sugar on Polycomb

A wide variety of nuclear and cytosolic proteins in human cells carry an O-linked sugar modification,
N
-acetylglucosamine (GlcNAc), which is added by the highly conserved O-linked GlcNAc transferase, Ogt.

Gambetta
et al.

(p.
93
, published online 28 May; see the Perspective by

Simon

) show that in
Drosophila
, Ogt is encoded by super sex combs, a classic Polycomb group gene known for its role in repressing developmental regulator genes. GlcNAc modification is highly enriched at chromosomal sites bound by Polycomb group proteins, and one of these, Polyhomeotic, is modified by Ogt. Thus, in
Drosophila
, it seems that O-linked GlcNAc has a very specific role to effect Polycomb repression.
IL-21R on T Cells Is Critical for Sustained Functionality and Control of Chronic Viral Infection
Authors: Fröhlich Anja , Kisielow Jan , Schmitz Iwana , Freigang Stefan , Shamshiev Abdijapar T. , Weber Jacqueline , Marsland Benjamin J. , Oxenius Annette , Kopf Manfred
Published: May 2009

Controlling Chronic Viral Infections

Chronic viral infections such as HIV and hepatitis B and C viruses are major public health concerns. T cell—mediated immune responses are critical for controlling viral infections. In contrast to acute infections, chronic viral infections are characterized by “exhausted” cytotoxic CD8
+
T cells, cells which exhibit reduced proliferative capacity, cytokine secretion, and cytotoxicity. Treatments that reverse exhaustion result in increased viral control. Despite their exhaustion, these CD8
+
T cells eventually help to control chronic infections by killing virally infected cells, and require CD4
+
T cell help to do so. How do CD4
+
T cells provide help to CD8
+
T cells during chronic infection (see the Perspective by

Johnson and Jameson

)?

Elsaesser
et al.

(p.
1569
, published online 7 May),

Yi
et al.

(p.
1572
, published online 14 May), and

Fröhlich
et al.

(p.
1576
, published online 28 May) now show that the cytokine, interleukin-21 (IL-21), known to be critical for the differentiation of certain CD4
+
T cell effector subsets, is an essential factor produced by CD4
+
T cells that helps CD8
+
T cells to control chronic lymphocytic choriomeningitis virus infection in mice. Acute and chronic infections resulted in differing amounts of IL-21 production by virus-specific CD4
+
T cells. CD8
+
T cells required IL-21 directly, and when CD8
+
T cells were unable to signal through IL-21 or IL-21 was not available, they were reduced in number, exhibited a more exhausted phenotype, and were not able to control the virus. In contrast, the absence of IL-21–dependent signaling did not affect primary CD8
+
T cell responses to acute infection or responses to a viral rechallenge, suggesting that differentiation of memory CD8
+
T cells is independent of IL-21.
Using Indigenous Australian drama to break cultural barriers in healthcare relationships
Authors: Matharu K
Published: May 2009

Since colonisation, the marginalisation of Indigenous Australians has adversely affected their language, culture and health. Mainstream society has failed to address social differences and establish culturally-appropriate health programmes for these groups. This paper extracts important humanistic themes within the context of health from four Indigenous Australian plays written during a period of social unrest in response to past oppression: (1)The dreamers, by Jack David; (2)Murras, by Eva Johnson; (3)Coordah, by Richard Walley; and (4)The keepers, by Bob Maza. These plays will be analysed to (a) illuminate human suffering from an indigenous perspective, based upon social and cultural planes of analysis; (b) understand the socio-cultural basis of poor health; and (c) instruct healthcare professionals that health is a social construct that can be interpreted as the product of select plays that are not solely based upon an illness narrative.
Language, games and the role of interpreters in psychiatric diagnosis: a Wittgensteinian thought experiment: Table 1
Authors: Thomas P , Shah A , Thornton T
Published: May 2009

British society is becoming increasingly culturally and linguistically diverse. This poses a major challenge to mental health services charged with the responsibility to work in ways that respect cultural and linguistic difference. In this paper we investigate the problems of interpretation in the diagnosis of depression using a thought experiment to demonstrate important features of language-games, an idea introduced by Ludwig Wittgenstein in his late work,Philosophical investigations. The thought experiment draws attention to the importance of culture and contexts in understanding the meaning of particular utterances. This has implications not only for how we understand the role of interpreters in clinical settings, and who might best be suited to function in such a role, but more generally it draws attention to the importance of involving members of black minority ethnic (BME) communities in working alongside mainstream mental health services. We conclude that the involvement of BME community development workers inside, alongside and outside statutory services can potentially improve the quality of care for people from BME communities who use these services.
Narrating the Holocaust: in pursuit of poetic representations of health
Authors: Rapport F , Sparkes A C
Published: May 2009

This paper considers the scope of poetic representation for exploring notions of health and wellbeing in the testimony of Holocaust survivors. The paper is based on the representation, through poetic form, of testimony derived from multiple in-depth interviews with a Holocaust survivor, Anka, in south-east Wales. This paper concentrates on two of those interviews, the first a life story and the second an interview focusing on health, illness and wellbeing. Two poetic representations, one derived from each interview, provide examples of the principal investigator’s response to the oral testimony, and the authors explore how these forms can present authentic and rigorous data distillates without detracting from the emotive, contextualised and powerful messages of the original text. The poetic representations offer an analysis of the survivor’s life experiences, especially in Auschwitz concentration camp, and her personal perspective on her health and wellbeing. The authors discuss the value of poetic representation as a methodological approach, consider the poetic form for working with survivor stories and suggest how others might judge these pieces, to highlight the strengths and weaknesses of these alternative forms of data representation. They also consider the role of the researcher and Anka in creating the final product and the effect of Anka’s voice on the researchers’ work.
Study on correlation of signal molecule genes and their receptor-associated genes with rat liver regeneration
Authors: Xu Cun-Shuan , Shao Heng-Yi , Du Bin
Published: May 2009

To investigate the effect of signal molecules and their receptor-associated genes on rat liver regeneration (LR) at the transcriptional level, the associated genes were originally obtained by retrieving the databases and related scientific publications; their expression profiles in rat LR were then checked using the Rat Genome 230 2.0 microarray. The LR-associated genes were identified by comparing gene expression difference between partial hepatectomy groups and operation-control groups. A total of 454 genes were proved to be LR related. The genes associated with the seven kinds of signal molecules (steroid hormones, fatty acid derivatives, protein and polypeptide hormones, amino acids and their derivatives, choline, cytokines, and gas signal molecules) were detected to be enriched in a cluster characterized by upregulated expression in LR. The number of genes related to the seven kinds of signal molecules was, in sequence, 63, 27, 100, 102, 16, 166, and 18. The 1027 frequencies of upregulation and 823 frequencies of downregulation in total as well as 42 types of different expression patterns suggest the complex and diverse gene expression changes in LR. It is presumed that signal molecules played an important role in metabolism, inflammation, cell proliferation, growth and differentiation, etc., during rat LR.
Mapping barleyDsinsertions using wheat deletion lines reveals high insertion frequencies in gene-rich regions with high to moderate recombination rates
Authors: Randhawa Harpinder S. , Singh Jaswinder , Lemaux Peggy G. , Gill Kulvinder S.
Published: May 2009

Gene distribution is highly uneven in the large genomes of barley and wheat; however, location, order, and gene density of gene-containing regions are very similar between the two genomes. Flanking sequences from 35 unique, single-copy, barley Ds insertion events were physically mapped using wheat nullisomic-tetrasomic, ditelosomic, and deletion lines. Of the 35 sequences, 23 (66%) detected 34 loci mapping on all 7 homoeologous wheat groups. Seven sequences were not mapped owing to lack of polymorphism and the remaining 5 (14%) were barley-specific. All 34 loci physically mapped to the previously identified gene-rich regions (GRRs) of wheat, making the contained genes candidates for targeted mutagenesis by remobilization. Transpositions occurred preferentially into GRRs with higher recombination rates. The GRRs containing 17 of the 23 Ds insertions accounted for 60%–89% of the respective arm’s recombination. The remaining 6 (17%) insertions mapped to GRRs with <15% of the arm’s recombination. Overall, kb/cM estimates for the Ds-containing GRRs were twofold higher than those for regions without insertions. These results suggest that all genes may be targeted by transposon-based gene cloning, although the transposition frequency for genes present in recombination-poor regions is significantly less than that present in highly recombinogenic regions.
Risk-based framework for accommodating uncertainty in highway geometric design
Authors: Ismail Karim , Sayed Tarek
Published: May 2009

The development of highway standard design models involves various assumptions regarding design inputs and the road environment. This paper suggests an improvement to the treatment of uncertainty in design inputs by replacing the current deterministic approach with a reliability-based framework. Reliability theory deals with the propagation of quantified variability in design inputs throughout the design process. In such a framework, each design output corresponds to a theoretical probability of noncompliance to design requirements. These probabilities can be used to assess and compare the a priori safety level associated with various design scenarios. This paper proposes that such a priori safety level of standard design outputs should be consistent and close to a prespecified target level. A set of methods is proposed to determine a target value for design safety. A general framework for calibrating standard design models is presented. To demonstrate the concept, the paper presents an application of the calibration framework to the standard design model of crest vertical curves. Calibrated design charts are constructed to yield a consistent design safety level.
Arsenic removal from groundwater through iron oxyhydroxide coated waste productsA paper submitted to the Journal of Environmental Engineering and Science.
Authors: Abdallah Elsadig A.M. , Gagnon Graham A.
Published: May 2009

The goal of this research was to remove arsenic from groundwater supplies via adsorption into media obtained from waste material generated as by-products from glass recycling programs and the seafood industry such as crushed glass and scallop shells. During the course of this research four new adsorbents were developed: ferric hydroxide coated crushed glass (FHCCG); ferric oxide coated crushed glass (FOCCG); ferric hydroxide coated scallop shells (FHCSS); and ferric oxide coated scallop shells (FOCSS). The adsorbents were characterized through evaluation of their structure, surface area, chemical composition, iron content, and coating stability. Efficiency of the adsorbents to remove arsenic from water was examined through batch kinetic and isotherm adsorption experiments. The adsorption capacity of the adsorbents was also evaluated by performing column experiments using real ground waters and a synthetic water. Arsenic removal to a concentration less than 10 μg/L was achieved with the FHCSS and more than 9000 bed volumes of water were treated before the breakthrough point was reached. The research results revealed that scallop shells coated with ferric hydroxideperformed better than crushed glass coated with ferric hydroxide. Both FOCCG and FOCSS had poor arsenic removal compared with FHCSS and granular ferric hydroxide (GFH). Ferric hydroxide coated scallop shells performed similarly to GFH.
Cronobacterspp. (« Enterobacter sakazakii » sensu lato) : implication dans la contamination des préparations en poudre pour nourrissons et enfants en bas âge
Authors: Proudy Isabelle
Published: May 2009

Species of the Cronobacter genus (“ Enterobacter sakazakii ” s. l.) are emergent food-borne pathogens that can cause rare but severe neonatal meningitis, bacteriaemia, and necrotizing enterocolitis. Preterm, low-birth-weight, and immuno-compromised infants exposed to these bacterial species are at particular risk. Over the last 50 years, the literature has reported, mainly in newborn children, more than one hundred cases of infection due to these pathogens. The objective of this review was to synthesize the recent advances in knowledge of species of the Cronobacter genus, in particular with regards to taxonomy, physiology, pathogenicity, clinical cases, the methods for detection, isolation, and characterization, and their presence in powdered formulae for infants and young children, which were identified as the main infection vector. Researchers and international public health authorities have explored the ways contamination occur to better control the risks of pathogen development. Appropriate analysis and control measures were implemented in areas processing powdered formulae for infants and young children, and caregivers and families were informed to undertake good hygienic practices.
Use of the DNA Checkerboard hybridization method for detection and quantitation of Candida species in oral microbiota
Authors: do Nascimento Cássio , Ferreira de Albuquerque Junior Rubens , Issa João Paulo Mardegan , Ito Izabel Yoko , Lovato da Silva Cláudia Helena , de Freitas Oliveira Paranhos Helena , Freitas de Souza Raphael
Published: May 2009

The DNA Checkerboard method enables the simultaneous identification of distinct microorganisms in a large number of samples and employs up to 45 whole genomic DNA probes to gram-negative and gram-positive bacterial species present in subgingival biofilms. Collectively, they account for 55%–60% of the bacteria in subgingival biofilms. In this study, we present the DNA Checkerboard hybridization as an alternative method for the detection and quantitation of Candida species in oral cavities. Our results reveal that DNA Checkerboard is sensitive enough and constitutes a powerful and appropriate method for detecting and quantifying Candida species found in the oral cavity.
Generation and characterization of the antibacterial activity of a novel hybrid antimicrobial peptide comprising functional domains from different insect cecropins
Authors: Plunkett Richard M. , Murray Stuart I. , Lowenberger Carl A.
Published: May 2009

The search for new antimicrobial compounds involves finding novel sources of chemotherapeutic compounds or manipulating and combining structures from existing molecules. Small antimicrobial peptides (AMPs) are components of innate immune defenses characterized in greatest detail in insect-derived AMPs. We have generated hybrid AMPs (hAMPs) by combining functional motifs from different insect AMPs as a proof of principle that we can generate molecules with lower minimum inhibitory concentrations, and with different activity and target specificity than either parent molecule. A two-helix, cecropin-like hAMP was created by linking the N-terminal α helix of cecropin A from Aedes aegypti to the C-terminal α helix of cecropin A1 from Drosophila melanogaster . This molecule exhibits antibacterial activity at sub-micromolar concentrations with a target specificity that differs from either parent molecule. Antibacterial activity of the hybrid molecule was found to be greater against Gram-negative than Gram-positive bacteria. No hemolysis was observed in sheep red blood cells exposed to concentrations up to 50 µmol/L, suggesting the peptide is not detrimental to eukaryotic cells.
Subinhibitory concentrations of fluconazole increase the intracellular sodium content in both fluconazole-resistant and -sensitive Candida albicans strains
Authors: Kolecka Anna , Krauke Yannick , Bujdakova Helena , Sychrova Hana
Published: May 2009

Fluconazole-sensitive (SC 5314) and -resistant (clinical isolate 1173) Candida albicans strains were compared in terms of their osmotolerance and tolerance to toxic sodium cations. The two strains did not differ in their tolerance to high osmotic pressure in general but exhibited distinct sensitivities to sodium cations. Although the fluconazole-resistant 1173 strain contained, under all conditions tested, significantly lower intracellular amounts of Na+, it was much more sodium sensitive than the SC 5314 strain. The addition of subinhibitory concentrations of fluconazole to media supplemented with NaCl significantly influenced the growth of both strains and resulted in substantially elevated intracellular sodium concentrations compared with growth in medium containing NaCl but no fluconazole.
Beneficial role of plant growth promoting bacteria and arbuscular mycorrhizal fungi on plant responses to heavy metal stress
Authors: Gamalero Elisa , Lingua Guido , Berta Graziella , Glick Bernard R.
Published: May 2009

Heavy metal pollution is a major worldwide environmental concern that has recently motivated researchers to develop a variety of novel approaches towards its cleanup. As an alternative to traditional physical and chemical methods of environmental cleanup, scientists have developed phytoremediation approaches that include the use of plants to remove or render harmless a range of compounds. Both plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) can be used to facilitate the process of phytoremediation and the growth of plants in metal-contaminated soils. This review focuses on the recent literature dealing with the effects of plant growth-promoting bacteria and AM fungi on the response of plants to heavy metal stress and points the way to strategies that may facilitate the practical realization of this technology.
Bacterial diversity of soil samples from the western Himalayas, India
Authors: Gangwar Pooja , Alam Syed Imteyaz , Bansod Sunita , Singh Lokendra
Published: May 2009

High-altitude cold habitats of the Himalayas are little explored with respect to bacterial diversity. Diverse bacterial species and phylotypes obtained by culture-dependent and culture-independent approaches are reported here. Phylogenetic analysis and modulation of bacterial diversity with altitude and available organic carbon content are also described. Psychrophilic and psychrotolerant bacteria dominated the Himalayan habitats, accounting for 60% of the cultivated strains. Isolates produced one or more (up to five) hydrolytic enzymes, lipase being the one secreted by most strains (62%). Partial 16S rRNA gene sequences were obtained for 99 bacterial strains and 74 clones obtained from soil samples from the western Himalayas. Forty-five percent of cultured bacterial strains belonged to the Proteobacteria group with 39% belonging to γ-Proteobacteria. Firmicutes was the second most abundant class with 32% of the total isolates followed by Actinobacteria (16%) and Bacteroidetes (6%). Most of the strains belonged to the genus Bacillus (30%) followed by Pseudomonas (24%) and Arthrobacter (12%). In culture-independent studies, phylotypes belonging to the Proteobacteria were dominant (73%) with the majority being β-Proteobacteria (31%). The bacterial diversity exhibited an altitude gradient with a gradual decline in the number of genera with increase in altitude. The isolates exhibited close phylogenetic affinities to bacteria from other cold habitats.
GROUPS OF GENERALIZED FLUX TRANSFORMATIONS IN THE SPACE OF GENERALIZED CONNECTIONS
Authors: VELHINHO J. M.
Published: May 2009

We present a group of transformations in the space of generalized connections that contains the set of transformations generated by the flux variables of loop quantum gravity. This group is labeled by certain SU(2)-valued functions on the bundle of directions in the spatial manifold. A further generalization is obtained by considering functions that depend on germs of analytic curves, rather than just on directions.
Discharge of the hypoglossal nerve cannot distinguish eupnea from gasping, as defined by phrenic discharge, in the in situ mouse
Authors: St. John Walter M. , Leiter J. C.
Published: May 2009

If normal, eupneic breathing fails, gasping is recruited. Serotonin was proposed as essential for gasping, based on findings using an in vitro mouse preparation. This preparation generates rhythmic activities of the hypoglossal nerve that are considered to be akin to both eupnea and gasping. In previous studies, gasping of in situ rat and mouse preparations continued unabated following blockers of receptors for serotonin. However, hypoglossal activity was not recorded in the mouse, and we hypothesized that its discharge during gasping might be dependent on serotonin. In the in situ mouse preparation, hypoglossal discharge had varying and inconsistent patterns during eupnea, discharging concomitant with the phrenic burst, at varying intervals between phrenic bursts, or was silent in some respiratory cycles. In eupnea, phrenic discharge was incrementing, whereas hypoglossal discharge was decrementing in 15 of 20 preparations. During ischemia-induced gasping, peak phrenic height was reached at 205 ± 17 ms, compared with 282 ± 27.9 ms after the start of the eupneic burst ( P < 0.002). In contrast, rates of rise of hypoglossal discharge in gasping (peak at 233 ± 25 ms) and eupnea (peak at 199 ± 19.2 ms) were the same. The uncoupling of hypoglossal from phrenic discharge in eupnea was exacerbated by methysergide, an antagonist of serotonin receptors. These findings demonstrate that hypoglossal discharge alone cannot distinguish eupnea from gasping nor, in eupnea, can hypoglossal activity be used to differentiate neural inspiration from expiration. These findings have significant negative implications for conclusions drawn from the in vitro medullary slice of mouse.
A transient antioxidant stress response accompanies the onset of disuse atrophy in human skeletal muscle
Authors: Dalla Libera Luciano , Ravara Barbara , Gobbo Valerio , Tarricone Elena , Vitadello Maurizio , Biolo Gianni , Vescovo Giorgio , Gorza Luisa
Published: May 2009

It is presently unknown whether oxidative stress increases in disused skeletal muscle in humans. Markers of oxidative stress were investigated in biopsies from the vastus lateralis muscle, collected from healthy subjects before [ time 0 (T0)], after 1 wk (T8), and after 5 wk (T35) of bed rest. An 18% decrease in fiber cross-sectional area was detected in T35 biopsies ( P < 0.05). Carbonylation of muscle proteins significantly increased about twofold at T35 ( P < 0.02) and correlated positively with the decrease in fiber cross-sectional area ( P = 0.04). Conversely, T8 biopsies showed a significant increase in protein levels of heme oxygenase-1 and glucose-regulated protein-75 (Grp75)/mitochondrial heat shock protein-70, two stress proteins involved in the antioxidant defense ( P < 0.05). Heme oxygenase-1 increase, which involved a larger proportion of slow fibers compared with T0, appeared blunted in T35 biopsies. Grp75 protein level increased threefold in T8 biopsies and localized especially in slow fibers ( P < 0.025), to decrease significantly in T35 biopsies ( P < 0.05). Percent change in Grp75 levels positively correlated with fiber cross-sectional area ( P = 0.01). Parallel investigations on rat soleus muscles, performed after 1–15 days of hindlimb suspension, showed that Grp75 protein levels significantly increased after 24 h of unloading ( P = 0.02), i.e., before statistically significant evidence of muscle atrophy, to decrease thereafter in relation to the degree of muscle atrophy ( P = 0.03). Therefore, in humans as in rodents, disuse muscle atrophy is characterized by increased protein carbonylation and by the blunting of the antioxidant stress response evoked by disuse.
NRF2 intron 3 A/G polymorphism is associated with endurance athletes’ status
Authors: Eynon Nir , Sagiv Moran , Meckel Yoav , Duarte José Alberto , Alves Alberto Jorge , Yamin Chen , Sagiv Michael , Goldhammer Ehud , Oliveira José
Published: May 2009

The aim of this study was to determine the frequency distribution of nuclear respiratory factor 2 ( NRF2) intron 3 A/G polymorphism (rs7181866) among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy controls. Results showed that there was a significantly higher proportion of the AG genotype, rather than the AA genotype, in the group of endurance athletes compared with the sprinters ( P = 0.014) and controls ( P = 0.0008). However, the sprinters’ genotype and allele frequencies were similar to those of the control group ( P = 0.62 for genotype distribution percentage). These results were even more pronounced when we compared between the subgroups of 20 elite endurance athletes (those who had represented Israel in a world track-and-field championship or in the Olympic Games) and 54 national-level endurance athletes. In the group of elite endurance athletes the G allele was more frequent than in the national-level endurance athletes ( P = 0.047). We conclude that 1) in Israeli athletes the NRF2 AG genotype is more frequent in elite endurance athletes than in sprinters, and 2) within the endurance group the NRF2 AG genotype and the G allele are more frequent in elite athletes, suggesting a positive association between the AG genotype, and possibly the G allele, and the likelihood of being an elite endurance athlete.
Pressor responses to isometric biting are evoked by somatosensory receptors in periodontal tissue in humans
Authors: Okada Yoshiyuki , Kamijo Yoshi-ichiro , Okazaki Kazunobu , Masuki Shizue , Goto Masaki , Nose Hiroshi
Published: May 2009

Jaw muscle contraction, such as mastication and biting (BT), is known to evoke pressor responses. We examined whether the responses were evoked by somatosensory receptors in periodontal tissue and, moreover, whether they were accompanied by altered arterial baroreflex sensitivity. In the first experiment, we measured mean arterial pressure, heart rate, and muscle sympathetic nerve activity from the peroneal nerve during 2-min isometric BT at 50% maximal voluntary contraction before [control (CNT)] and after pharmacological alveolar nerve block (BLK) in eight young men, while monitoring finger cutaneous vascular conductance, gingival vascular conductance (GVC), surface electromyogram of masseter muscle, and BT force. In the second experiment, cardiac and sympathetic baroreflex sensitivities were successfully determined in eight and five of the subjects, respectively, by the modified Oxford method during 5-min BT at 30% maximal voluntary contraction and also during resting without BT in CNT and BLK, respectively. In the first experiment, although BT in CNT and BLK significantly increased mean arterial pressure, heart rate, and total muscle sympathetic nerve activity (burst amplitude × burst incidence), and decreased finger cutaneous vascular conductance and GVC ( P < 0.05), all changes except GVC were markedly attenuated in BLK ( P < 0.05). There were no significant differences in integrated electromyogram and BT force among any trials. In the second experiment, although BT in CNT significantly decreased cardiac and sympathetic baroreflex sensitivities (both, P < 0.05), these changes disappeared in BLK. These results suggest that somatosensory receptors in periodontal tissue were involved in pressor responses to isometric BT, which was accompanied by decreased arterial baroreflex sensitivity.
Contractility of Diabetic Human Corpus Cavernosum Smooth Muscle in Response to Serotonin Mediated via Rho-Kinase
Authors: Murat Nergis , Soner Burak Cem , Demir Omer , Esen Adil , Gidener Sedef
Published: May 2009

Background/Aims: Serotonin (5-hydroxytryptamine, 5-HT)-induced contraction and the involvement of RhoA/Rho-kinase pathway in the 5-HT-induced contraction was investigated isometrically in vitro in both diabetic and nondiabetic human corpus cavernosum (HCC) tissues. Methods: HCC tissues were obtained from 12 patients. The response to 5-HT (10–9 to 10–5 mol/l) was studied in isolated HCC tissues in the absence and in the presence of a Rho-kinase inhibitor (Y-27632). Results: Preincubation with Y-27632 attenuated maximum contractions induced by 5-HT in tissues of both nondiabetics and diabetics. When diabetic and nondiabetic groups were compared, no significant difference was seen in 5-HT-induced contraction alone, but in the presence of Y-27632, 5-HT-induced contraction was significantly higher in the diabetic group. Conclusion: These results suggest that the Rho-kinase-mediated pathway plays an important role for 5-HT-induced contraction in diabetic corpus cavernosum tissues.
Sleep Apnea: Traffic and Occupational Accidents – Individual Risks, Socioeconomic and Legal Implications
Authors: Rodenstein Daniel
Published: May 2009

Obstructive sleep apnea has been associated with a high risk for motor vehicle accidents, probably the highest of all risks due to medical conditions. Treatment of sleep apnea with nasal continuous positive airway pressure appears to reduce the risk of traffic accidents to the one of the general population. The risk for accidents may also be increased in untreated patients in the home and work environment. The increased risk seems unrelated to the symptom of daytime excessive sleepiness, and in many studies lacks a clear dose-response relationship with respect to the severity of apneas and hypopneas. The association of sleep apnea, chronic sleep deprivation and consumption of hypnotics or alcohol has not been thoroughly studied, although alcohol has been considered as a confounding variable in some studies. The cost of traffic accidents due to sleep apnea has been estimated to be so high that diagnosing and treating all drivers with sleep apnea in the USA would be cost saving and result in a decrease in society costs related to the disease. Driving licenses are delivered according to national legislations. These are all but uniform, especially concerning sleep apnea. Even within the European Union, where a minimum set of rules is mandatory for all countries, sleep apnea is not included in the minimum. Therefore, drivers are left in a very uncomfortable position, behaving according to the law in one country but being unlawful once the border with the neighbor country is crossed. Physicians are also in a very difficult position if they have to counsel their patients on the best attitude when travelling by car. The situation is even worse for commercial drivers, for whom the legislation is more severe but leaves sleep apnea uncovered in many countries. This is all the more disturbing if one considers that sleep apnea can be suspected, screened and diagnosed with relative ease, and that once diagnosed the adequate treatment allows for safe driving. The inclusion of sleep apnea in the European traffic license regulations would represent a step forward towards safe routes for patients and healthy people alike.
Blutspenderbefragung zum Thema “Aufwandsentschädigung für Blutspender”
Authors: Zeiler T. , Kretschmer V.
Published: May 2009

Hintergrund: Die finanzielle Aufwandsentschädigung für Blutspender, wie sie der-zeit in Deutschland von den staatlich-kommunalen Blutspendediensten gehandhabt wird, ist vor allem international umstritten. Es wird befürchtet, daβ dadurch Spender aus sogenannten Risikogruppen angeworben werden. Statt dessen werden andere Anreizsysteme diskutiert. Nach dem sogenannten AIDS-Skandal in Deutschland ware eine Anderung der Spendemotivation mit erhöhter Bereitschaft zum Verzicht auf eine finanzielle Aufwandsentschädigung zu erwarten gewesen. Daher führten wir eine aktuelle Befragung durch, in der sowohl der Verzicht auf eine finanzielle Vergütung als auch Möglichkeiten einer bargeldlosen Aufwandsentschädigung und andere Anreizsysteme auf ihre Akzeptanz beim Spender geprüft wurden. Material und Methode: In der Zeit vom 1.3.1994 bis zum 30.4.1994 wurden 1157 Blutspender der Universitätsblutbank Marburg mittels eines anonymisierten Frage-bogens im Rahmen einer Vollblutspende befragt. Neben der Erfassung der oben an-gesprochenen Aspekte wurden demoskopische Daten erhoben (Alter, Geschlecht, Beruf, Anfahrtsweg). Ergebnisse: Den ersatzlosen Wegfall der Aufwandsentschädigung lehnten 86,1% der Spender ab, 77% wurden dann nicht mehr spenden. Mit der Überweisung der Aufwandsentschädigung auf ein Bankkonto waren 78,6%, mit der Verwendung von Verrechnungsschecks 68,7% einverstanden. Theater-, Konzert-, Kinokarten- oder Restaurantgutscheine als Ersatz wurden nur von 27,3% der Spender befürwortet, 36,9% wurden unter diesen Umständen weiter spenden. Mit zunehmendem Lebens-alter und steigender Anzahl der geleisteten Spenden wurde – weitgehend unab-hängig vom sozialen Status – gröβerer Wert auf die Beibehaltung der finanziellen Aufwandsentschädigung gelegt. Diskussion: Der Wegfall der finanziellen Aufwandsentschädigung würde zu einem erheblichen Rückgang der Spendebereitschaft bei den Spenderstämmen der staatlich-kommunalen Blutspendedienste führen. Eine Erhöhung der Virussicherheit der Blutprodukte ware dadurch jedoch nicht zu erreichen, da gerade die langjährigen Stammspender verprellt wurden. Mit erheblichen Engpässen, insbesondere in der spezifisch kliniknahen Blutversorgung, ware zu rechnen.