bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonequiaxial Grain Growth and Polytype Transformation of Sintered α‐Silicon Carbide and β‐Silicon Carbide
Authors: Tanaka Hidehiko , Hirosaki Naoto , Nishimura Toshiyuki , Shin Dong‐Woo , Park Sam‐Shik
Published: July 2009

α(6H)‐ and β(3C)‐SiC powders were sintered with the addition of AlB2 and carbon. α‐SiC powder could be densified to ∼98% of the theoretical density over a wide range of temperatures from 1900° to 2150°C and with the additives of 0.67–2.7 mass% of AlB2 and 2.0 mass% of carbon. Sintering of the β‐SiC powder required a temperature of >2000°C for densification with these additives. Grains in the α‐SiC specimens grew gradually from spherical‐shaped to plate‐shaped grains at 2000°C; the 6H polytype transformed mainly to 4H. On the other hand, grains in the β‐SiC largely grew at >2000°C; the 3C polytype transformed to 4H, 6H, and 15R. The stacking faults introduced in grains were denser in β‐SiC than in α‐SiC. The rapid grain growth in the β‐SiC specimen was attributed to polytype transformation from the unstable 3C polytype at the sintering temperature.
Martensitic Relief Observation by Atomic Force Microscopy in Yttria‐Stabilized Zirconia
Authors: Deville Sylvain , Chevalier Jérôme
Published: July 2009

The tetragonal to monoclinic (t–m) phase transformation of zirconia has been the object of extensive investigations of the past 20 years and is now recognized as being of martensitic nature. However, martensitic transformation has only been observed by transmission electron microscopy or indirect methods. Though the benefit on the fracture toughness and crack resistance was the main interest, the transformation is now considered for its consequences on the degradation of the material. The use of atomic force microscopy reported here allowed the observation of the first stages of martensite relief growth and of new martensitic features.
Contactless Density Measurement of Liquid Nd‐Doped 50%CaO–50%Al2O3
Authors: Paradis Paul‐François , Yu Jianding , Ishikawa Takehiko , Yoda Shinichi
Published: July 2009

The density of neodymium‐doped calcium aluminate (<1 mol% Nd2O3·50% CaO·50% Al2O3) liquid was measured over a wide temperature range using an electrostatic levitation furnace. The density was obtained using an UV‐based imaging technique that allowed excellent illumination throughout all phases of processing, including elevated temperatures. Over the 1560–2000 K temperature range, the density could be expressed as ρ(T) = 2.83 × 103– 0.21(T–Tm) (kg·m−3) (±2%) with Tm= 1878 K, which yielded a volume coefficient of thermal expansion α(T) = 7.5 × 10−5 K−1.
Rapid Prototyping of Piezoelectric Ceramics via Selective Laser Sintering and Gelcasting
Authors: Guo Dong , Li Long‐tu , Cai Kai , Gui Zhi‐lun , Nan Ce‐wen
Published: July 2009

This article presents a new lost mold rapid prototyping method which combines selective laser sintering (SLS) and gelcasting techniques for fabricating piezoelectric ceramics. SLS was used to fabricate sacrificial molds of the desired structure of the ceramic part. Then aqueous PZT (lead zirconate titanate) suspension was cast in the mold and solidified in situ through formation of a three‐dimensional network gel. Because the polymer mold can be easily removed at the initial stage of sintering and the gelcast PZT body has a high green strength, the desired geometry of the PZT part can be completely retained after sintering of the ceramics. Complex‐shaped PZT parts were successfully fabricated after using concentrated PZT suspension with low viscosity. Densities and electrical properties, such as the d33, the relative permittivity ε, the dielectric loss tgδ and the electromechanical coupling factor Kp of the gelcast PZT parts were also compared with those of the die‐pressed PZT samples. The results indicated that the gel‐forming process did not deteriorate the electrical properties of the samples, if proper dispersant was selected in developing concentrated ceramic slurry.
Synthesis and Sintering of Cerium(II) Monosulfide
Authors: Hirai Shinji , Sumita Eiji , Shimakage Kazuyoshi , Uemura Yoichiro , Nishimura Toshiyuki , Mitomo Mamoru
Published: July 2009

Cerium monosulfide (CeS) powder was synthesized by the reduction of Ce2S3 powder with metallic Ce, which was obtained from ceria (CeO2) powder using carbon disulfide (CS2) gas. To obtain the maximum amount of CeS from a mixture of Ce2S3 and Ce, an excess amount of metallic Ce, a stoichiometric composition, was necessary in the synthesis at 1273 K for 10.8 ks. The preliminary sintering experiments also were performed using a synthetic CeS powder containing a small amount of Ce, Ce2O2S, and β‐Ce2S3 as impurities. It was found that the oxygen content in the sintered compact decreases gradually as the sintering temperature increases, because of the removal of the impurities due to the evaporation of the volatile CeO. Single‐phase CeS was formed by sintering at 2173 K. To evaluate the activation energy for densification of single‐phase CeS, a CeS powder was prepared by milling an initial sintered compact and was used as an ingredient for hot‐press experiments. Densification data during hot‐press sintering were analyzed using a kinetic equation, showing that boundary diffusion is a rate‐limiting process. The results suggest that this boundary diffusion model can explain well the densification data, with an apparent activation energy of 479 kJ·mol‐1.
Producing Ceramic Foams with Hollow Spheres
Authors: Thijs Ivo , Luyten Jan , Mullens Steven
Published: July 2009

Ceramic foams have a large potential for many applications and can be produced in several ways. In the past, many have attempted to manufacture ceramic foams that combined sufficient strength and controlled microstructure. This study proposes a new two‐step processing route to fulfill these requirements. First, sacrificial cores are coated with ceramic powder slurry and packed in a die. Second, the cores are connected together using another ceramic slurry coating. After they are burned out and sintered, ceramic foam structures can be obtained that have a density <10% of theoretical density. By varying the size and shape of the initial cores, ceramic foams with tailor‐made microstructures can be easily produced.
Dofequidar fumarate sensitizes cancer stem‐like side population cells to chemotherapeutic drugs by inhibiting ABCG2/BCRP‐mediated drug export
Authors: Katayama Ryohei , Koike Sumie , Sato Shigeo , Sugimoto Yoshikazu , Tsuruo Takashi , Fujita Naoya
Published: July 2009

The ATP‐binding cassette (ABC) transporters (ABC‐T) actively efflux structurally and mechanistically unrelated anticancer drugs from cells. As a consequence, they can confer multidrug resistance (MDR) to cancer cells. ABC‐T are also reported to be phenotypic markers and functional regulators of cancer stem/initiating cells (CSC) and believed to be associated with tumor initiation, progression, and relapse. Dofequidar fumarate, an orally active quinoline compound, has been reported to overcome MDR by inhibiting ABCB1/P‐gp, ABCC1/MDR‐associated protein 1, or both. Phase III clinical trials suggested that dofequidar had efficacy in patients who had not received prior therapy. Here we show that dofequidar inhibits the efflux of chemotherapeutic drugs and increases the sensitivity to anticancer drugs in CSC‐like side population (SP) cells isolated from various cancer cell lines. Dofequidar treatment greatly reduced the cell number in the SP fraction. Estimation of ABC‐T expression revealed that ABCG2/breast cancer resistance protein (BCRP) mRNA level, but not the ABCB1/P‐gp or ABCC1/MDR‐associated protein 1 mRNA level, in all the tested SP cells was higher than that in non‐SP cells. Thein vitrovesicle transporter assay clarified that dofequidar had the ability to suppress ABCG2/BCRP function. Dofequidar treatment sensitized SP cells to anticancer agentsin vitro. We compared the antitumor efficacy of irinotecan (CPT‐11) alone with that of CPT‐11 plus dofequidar in xenografted SP cells. Although xenografted SP tumors showed resistance to CPT‐11, treatment with CPT‐11 plus dofequidar greatly reduced the SP‐derived tumor growthin vivo. Our results suggest the possibility of selective eradication of CSC by inhibiting ABCG2/BCRP. (Cancer Sci2009)
Reciprocal effect of mesenchymal stem cell on experimental autoimmune encephalomyelitis is mediated by transforming growth factor-β and interleukin-6
Authors: Liu X-J , Zhang J-F , Sun B , Peng H-S , Kong Q-F , Bai S-S , Liu Y-M , Wang G-Y , Wang J-H , Li H-L
Published: July 2009

Mesenchymal stem cells (MSCs) have the ability to suppress T cell proliferation and modulate cytokine production. Recently, MSCs have been shown to ameliorate autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE), but in some cases shown to stimulate lymphocyte proliferation. So far, mechanisms through which MSCs modulate immune reactions are still undefined. In this report we demonstrate that MSCs have the capacity for either stimulating or inhibiting myelin basic protein-specific T lymphocytes in a dose-dependent manner and modulate antigen-stimulated T cells to differentiate into either T helper type 17 or regulatory T cells, respectively, via pathways involving transforming growth factor-β and interleukin-6. These results may lead better utility of MSCs as a treatment for autoimmune disease.
Intravenous immunoglobulin preparations have no direct effect on B cell proliferation and immunoglobulin production
Authors: Heidt S , Roelen D L , Eijsink C , Eikmans M , Claas F H J , Mulder A
Published: July 2009

Intravenous immunoglobulin (IVIg) is used for treatment of a variety of immunological disorders and in transplantation. As one of its applications in transplantation is the reduction of donor specific antibodies in the circulation, we examined the direct effect of IVIg on essential parameters of human B cell responses in vitro. Purified human B cells, human B cell hybridomas and T cells were cultured in the presence of graded concentrations of IVIg to test its effect on their proliferative capacity. To address the effect of IVIg on immunoglobulin production, we designed a novel technique making use of quantitative polymerase chain reaction to assess IgM and IgG levels. IVIg failed to inhibit proliferation of human B cells and human B cell hybridomas. In contrast, when IVIg was added to T cell cultures, a dose-dependent reduction of the proliferative capacity was observed. IVIg did not affect the levels of IgM and IgG mRNA of activated B cells. Our data show that IVIg is not capable of directly inhibiting key B cell responses. Direct B cell inhibition by IVIg seems therefore unlikely, implying that alteration in humoral immunity by IVIg is due to indirect effects on T cells and/or interactions with circulating antibodies and complement factors.
Amoxicillin resistance with β‐lactamase production in Helicobacter pylori
Authors: Tseng Y.‐S. , Wu D.‐C. , Chang C.‐Y. , Kuo C.‐H. , Yang Y.‐C. , Jan C.‐M. , Su Y.‐C. , Kuo F.‐C. , Chang L.‐L.
Published: July 2009

Background  Amoxicillin‐resistant Helicobacter pylori with minimal inhibitory concentration (MIC) ≥ 256 mg L−1 was isolated from a gastritis patient. The aims were to investigate the mechanism of high‐level amoxicillin resistance in H. pylori.

Materials and methods  The β‐lactamase production was determined by means of nitrocefin sticks and the presence of gene encoding the β‐lactam antibiotic resistance enzyme TEM β‐lactamase was analysed by polymerase chain reaction (PCR), sequencing and dot‐blot hybridization. Sequencing analysis of pbp1A gene was performed and amoxicillin‐susceptible isolate was transformed with pbp1A PCR products from the resistant isolate. The expression of hefC efflux system was analysed using real‐time quantitative PCR.

Results  Activity of β‐lactamase was detected. Sequence analysis showed that the PCR product derived from H. pylori 3778 was identical to the blaTEM‐1 (GenBank accession EU726527). Dot‐blot hybridization confirmed the presence of β‐lactamase gene blaTEM‐1. By transformation of PCR product of mutated pbp1A gene from H. pylori 3778 into amoxicillin‐susceptible strain showed that substitutions in Thr556→Ser, Lys648→Gln, Arg649→Lys and Arg656→Pro contribute to low‐level amoxicillin resistance. The MIC of amoxicillin for the transformants was 0·75 mg L−1. Over‐expression of hefC was not found.

Conclusions  High‐level amoxicillin resistance is associated with β‐lactamase production in H. pylori. Low‐level amoxicillin resistance is linked to a point mutation on pbp1A. Because H. pylori can exchange DNA through natural transformation, spreading of blaTEM‐1 amoxicillin resistance gene among H. pylori is a potential threat when treating H. pylori infection.
Albedo estimates for land surface models and support for a new paradigm based on foliage nitrogen concentration
Authors: HOLLINGER D. Y. , OLLINGER S. V. , RICHARDSON A. D. , MEYERS T. P. , DAIL D. B. , MARTIN M. E. , SCOTT N. A. , ARKEBAUER T. J. , BALDOCCHI D. D. , CLARK K. L. , CURTIS P. S. , DAVIS K. J. , DESAI A. R. , DRAGONI D. , GOULDEN M. L. , GU L. , KATUL G. G. , PALLARDY S. G. , PAW U K. T. , SCHMID H. P. , STOY P. C. , SUYKER A. E. , VERMA S. B.
Published: July 2009

Vegetation albedo is a critical component of the Earth's climate system, yet efforts to evaluate and improve albedo parameterizations in climate models have lagged relative to other aspects of model development. Here, we calculated growing season albedos for deciduous and evergreen forests, crops, and grasslands based on over 40 site‐years of data from the AmeriFlux network and compared them with estimates presently used in the land surface formulations of a variety of climate models. Generally, the albedo estimates used in land surface models agreed well with this data compilation. However, a variety of models using fixed seasonal estimates of albedo overestimated the growing season albedo of northerly evergreen trees. In contrast, climate models that rely on a common two‐stream albedo submodel provided accurate predictions of boreal needle‐leaf evergreen albedo but overestimated grassland albedos. Inverse analysis showed that parameters of the two‐stream model were highly correlated. Consistent with recent observations based on remotely sensed albedo, the AmeriFlux dataset demonstrated a tight linear relationship between canopy albedo and foliage nitrogen concentration (for forest vegetation: albedo=0.01+0.071%N, r2=0.91; forests, grassland, and maize: albedo=0.02+0.067%N, r2=0.80). However, this relationship saturated at the higher nitrogen concentrations displayed by soybean foliage. We developed similar relationships between a foliar parameter used in the two‐stream albedo model and foliage nitrogen concentration. These nitrogen‐based relationships can serve as the basis for a new approach to land surface albedo modeling that simplifies albedo estimation while providing a link to other important ecosystem processes.
On the relationship between water table depth and water vapor and carbon dioxide fluxes in a minerotrophic fen
Authors: SONNENTAG O. , Van Der KAMP G. , BARR A. G. , CHEN J. M.
Published: July 2009

The focus of this study is the relationship between water table depth (WTD) and water vapor [evapotranspiration (ET)] and carbon dioxide [CO2; net ecosystem exchange (NEE)] fluxes in a fen in western Canada. We analyzed hydrological and eddy covariance measurements from four snow‐free periods (2003–2006) with contrasting meteorological conditions to establish the link between daily WTD and ET and gross ecosystem CO2 exchange (GEE) and ecosystem respiration (Reco; NEE=Reco−GEE), respectively: 2003 was warm and dry, 2004 was cool and wet, and 2005 and 2006 were both wet. In 2003, the water table (WT) was below the ground surface. In 2004, the WT rose above the ground surface, and in 2005 and 2006, the WT stayed well above the ground surface. There were no significant differences in total ET (∼316 mm period−1), but total NEE was significantly different (2003: 8 g C m−2 period−1; 2004: −139 g C m−2 period−1; 2005: −163 g C m−2 period−1; 2006: −195 g C m−2 period−1), mostly due to differences in total GEE (2003: 327 g C m−2 period−1; 2004: 513 g C m−2 period−1; 2005: 411 g C m−2 period−1; 2006: 556 g C m−2 period−1). Variation in ET is mostly explained by radiation (67%), and the contribution of WTD is only minor (33%). WTD controls the compensating contributions of different land surface components, resulting in similar total ET regardless of the hydrological conditions. WTD and temperature each contribute about half to the explained variation in GEE up to a threshold ponding depth, below which temperature alone is the key explanatory variable. WTD is only of minor importance for the variation in Reco, which is mainly controlled by temperature. Our study implies that future peatland modeling efforts explicitly consider topographic and hydrogeological influences on WTD.
On the International Code of Area Nomenclature (ICAN): a reply to Zaragüeta‐Bagils et al.
Authors: Parenti Lynne R. , Viloria ÁNgel L. , Ebach Malte C. , Morrone Juan J.
Published: July 2009

In 2007 the Systematic and Evolutionary Biogeographical Association (SEBA) wrote and ratified the first draft of the International Code of Area Nomenclature (ICAN), which was posted subsequently on the SEBA website. The ICAN was published, along with an explanatory discussion, by Ebach et al. (Journal of Biogeography, 35, 2008, 1153–1157), an article that is the subject of criticism by Zaragüeta‐Bagils et al. (Journal of Biogeography, 36, 2009, 1617–1618). We welcome discussion of the issues raised by these authors and respond to them briefly here. For many reasons, we reject the proposition that implementation of the ICAN be postponed until it is flawless. The ICAN has already been implemented. Further, it is the nature of nomenclatural codes to be proposed and then revised periodically to suit our applications. Most importantly, standardization of area names in biogeography is long overdue.
Unnoticed post‐void residual urine volume in people with moderate to severe intellectual disabilities: prevalence and risk factors
Authors: De Waal K. H. , Tinselboer B. M. , Evenhuis H. M. , Penning C.
Published: July 2009

Background  Increased post‐void residual urine volume (PVR) is often seen in geriatric populations. People with intellectual disabilities (ID) have risk factors in common with these populations.

Aims  To investigate in adults with ID:

Feasibility of portable ultrasound bladder scanning;

Prevalence of PVR; and

Relations with proposed risk factors for PVR.

Methods  In a cross‐sectional design, PVR was measured using ultrasound scanning in 346 adults with moderate to severe ID aged 18–82 years. Relationship between increased PVR and the following risk factors was assessed: age, level of ID, gender, ambulancy, medication, chronic illnesses, incontinence and profound multiple disabilities (PMD). Acceptation of scanning and manageability were noted.

Results  Feasibility: All participants were cooperatively undergoing the ultrasound scan and all outcomes were sufficiently interpretable. Prevalence: PVR ≥ 150 mL was newly identified in 30/346 persons (8.7%, 95% confidence interval 5.92–12.14). Associations: Higher age (P = 0.001), laxative use (P = 0.001), chronic illnesses other than epilepsy (P = 0.005), profound ID (P = 0.008), incontinence (P = 0.048) and immobility (P = 0.005) are determinants that were associated with urinary retention.

Conclusions  The bladder ultrasound scan is a feasible method to identify increased PVR in adults with more severe levels of ID. The prevalence of PVR in adults is similar to prevalences found in the geriatric general population.
A validity study of the Working Group's Orientation Test for individuals with moderate to severe intellectual disability
Authors: Pyo G. , Curtis K. , Curtis R. , Markwell S.
Published: July 2009

Background  Decline in orientation skill has been reported as an early indicator of Dementia of Alzheimer's Type (DAT). Orientation subtest of the Working Group's Test Battery was examined whether this test is useful to identify DAT patients among adults with moderate to severe ID.

Methods  Sixteen DAT patients and 35 non‐demented normal controls with moderate to severe ID were followed for a year using Orientation Test. The scores on the baseline evaluation and the longitudinal changes over a 1‐year period among the DAT patients and the normal controls were compared. The effects of age and etiologies of ID on the performance of Orientation were also examined.

Results  The DAT group's score was significantly poorer than that of the normal control group on the baseline evaluation. The score changes over the 1‐year period were not significantly different between the groups. However, there was a considerable overlap between the score distributions of the two groups. The effects of age and etiologies of ID on the performance of Orientation were not significant.

Conclusions  Screening DAT patients based only on the score of the Orientation Test of the Working Group's Test Battery may produce a large number of diagnostic errors.
Three‐dimensional surface texture visualization of bone tissue through epifluorescence‐based serial block face imaging
Authors: SLYFIELD Jr. C.R. , NIEMEYER K.E. , TKACHENKO E.V. , TOMLINSON R.E. , STEYER G.G. , PATTHANACHAROENPHON C.G. , KAZAKIA G.J. , WILSON D.L. , HERNANDEZ C.J.
Published: July 2009

Serial block face imaging is a microscopy technique in which the top of a specimen is cut or ground away and a mosaic of images is collected of the newly revealed cross‐section. Images collected from each slice are then digitally stacked to achieve 3D images. The development of fully automated image acquisition devices has made serial block face imaging more attractive by greatly reducing labour requirements. The technique is particularly attractive for studies of biological activity within cancellous bone as it has the capability of achieving direct, automated measures of biological and morphological traits and their associations with one another. When used with fluorescence microscopy, serial block face imaging has the potential to achieve 3D images of tissue as well as fluorescent markers of biological activity. Epifluorescence‐based serial block face imaging presents a number of unique challenges for visualizing bone specimens due to noise generated by sub‐surface signal and local variations in tissue autofluorescence. Here we present techniques for processing serial block face images of trabecular bone using a combination of non‐uniform illumination correction, precise tiling of the mosaic in each cross‐section, cross‐section alignment for vertical stacking, removal of sub‐surface signal and segmentation. The resulting techniques allow examination of bone surface texture that will enable 3D quantitative measures of biological processes in cancellous bone biopsies.
Ageing and overageing of lead–calcium alloys
Authors: ROSSI F. , LAMBERTIN M. , DELFAUT‐DURUT L. , MAITRE A. , VILASI M.
Published: July 2009

Lead–calcium alloys are commonly used for their high mechanical properties, compared with pure lead. These alloys evolve quickly at room temperature and could in a few months, or years, undergo a softening (overageing). During the last decade, much research has been carried out on the subject without any unanimous results, due mainly to the diversity of the alloy's transformations and the difficulties of observation (wide range of kinetics, heterogeneity of transformations, etc.). The use of several in situ techniques developed specifically for lead alloys in our laboratories has enabled us to identify five transformations in lead–calcium alloys. The structural hardening begins by two discontinuous transformations. The first one is complete and the second one of ordering type remains incomplete. The end of the hardening is due to a thin precipitation of Pb3Ca, which is followed by a coarsening (softening) of macroprecipitates aligned in strings. The last softening stage comes with the formation of lamellar Pb3Ca precipitates by coalescence of the macroprecipitates.
An experimental method for calibration of the plasmon mean free path
Authors: MELTZMAN H. , KAUFFMANN Y. , THANGADURAI P. , DROZDOV M. , BARAM M. , BRANDON D. , KAPLAN W.D.
Published: July 2009

Transmission electron microscopy specimens in the form of elongated, conical needles were made using a dual‐beam focused ion beam system, allowing the specimen thickness to be geometrically determined for a range of thickness values. From the same samples electron energy loss maps were acquired and the plasmon mean free path (λ) for inelastic scattering was determined experimentally from the measured values of specimen thickness. To test the method λ was determined for Ni (174 ± 17 nm), α‐Al2O3 (143 ± 14 nm), Si (199 ± 20 nm) and amorphous SiO2 (238 ± 12 nm), and compared both to experimental values of λ taken from the literature and to calculated values. The calculated values of λ significantly underestimate the true sample thickness for high accelerating voltages (300 kV) and large collection angles. A linear dependence of λ on thickness was confirmed for t/λ < 0.5–0.6, but this method also provides an approach for calibrating λ at sample thicknesses for which multiple scattering occurs, thus expanding the thickness range over which electron energy loss spectroscopy can be used to determine the absolute sample thickness (t/λ > 0.6). The experimental method proposed in this contribution offers a means to calibrate λ for any type of material or phase that can be milled using a focused ion beam system.
Spatial and temporal analysis of non‐steady elongation of rice leaves
Authors: PARENT BORIS , CONEJERO GENEVIEVE , TARDIEU FRANÇOIS
Published: July 2009

A precise knowledge of the temporal and spatial distributions of cell division and tissue expansion is essential for appropriate leaf sampling in omics studies and for analyses of plant–environment relations. Elongating leaves of rice were studied during their whole development for elongation rate, distribution of cell length, cell production rate and spatial distribution of growth in the leaf. In seven genotypes, the pattern of leaf elongation rate followed three phases: (1) an exponential increase before leaf appearance; (2) a short phase (2–4 d at 20 °C) with a stable leaf elongation rate around leaf appearance; and (3) a phase of 8–10 d with a progressive decrease in elongation rate. The profile of cell length along the leaf changed with time during the first and last phases, but was time invariant around appearance. We propose a method adapted to non‐steady elongation based on anatomical measurements, which was successfully tested by comparing it with the pricking method. It allowed analysis of the change with time in the spatial distribution of growth from initiation to end of leaf growth. The length of leaf zones with cell division and tissue elongation varied with time, with maximums of 21 and 60 mm respectively around leaf appearance.
Photobiological properties of the inhibition of etiolated Arabidopsis seedling growth by ultraviolet‐B irradiation
Authors: GARDNER GARY , LIN CHENTAO , TOBIN ELAINE M. , LOEHRER HEATHER , BRINKMAN DOUG
Published: July 2009

Alteration of ‘normal’ levels of ultraviolet‐B light (UV‐B, 280–320 nm) can affect plant chemical composition as well as growth; however, little is known about how plants perceive UV‐B light. We have carried out fluence response curves, and demonstrated that the growth inhibition of etiolated Arabidopsis thaliana seedlings by low fluence UV light is specific to UV‐B and not UV‐A (320–390 nm). The response shows reciprocity between duration and intensity, at least over a limited range, and thus depends only on photon fluence and not on photon flux. The action spectrum for this response indicates a peak of maximum effectiveness at 290 nm, and response spectra at different fluences indicate that the most effective wavelength at 30 000 µmol m–2 is 290 nm, whereas 300 nm light was the most effective at 100 000 µmol m–2. This response occurs in mutant seedlings deficient in cryptochrome, phytochrome or phototropin, suggesting that none of the known photoreceptors is the major UV‐B photoreceptor. Some null mutants in DNA repair enzymes show hypersensitivity to UV‐B, suggesting that even at low fluence rates, direct damage to DNA may be one component of the response to UV‐B.
Stomatal crypts may facilitate diffusion of CO2 to adaxial mesophyll cells in thick sclerophylls
Authors: HASSIOTOU FOTEINI , EVANS JOHN R. , LUDWIG MARTHA , VENEKLAAS ERIK J.
Published: July 2009

In some plants, stomata are exclusively located in epidermal depressions called crypts. It has been argued that crypts function to reduce transpiration; however, the occurrence of crypts in species from both arid and wet environments suggests that crypts may play another role. The genus Banksia was chosen to examine quantitative relationships between crypt morphology and leaf structural and physiological traits to gain insight into the functional significance of crypts. Crypt resistance to water vapour and CO2 diffusion was calculated by treating crypts as an additional boundary layer partially covering one leaf surface. Gas exchange measurements of polypropylene meshes confirmed the validity of this approach. Stomatal resistance was calculated as leaf resistance minus calculated crypt resistance. Stomata contributed significantly more than crypts to leaf resistance. Crypt depth increased and accounted for an increasing proportion of leaf resistance in species with greater leaf thickness and leaf dry mass per area. All Banksia species examined with leaves thicker than 0.6 mm had their stomata in deep crypts. We propose that crypts function to facilitate CO2 diffusion from the abaxial surface to adaxial palisade cells in thick leaves. This and other possible functions of stomatal crypts, including a role in water use, are discussed.
How do Regulatory T Cells Work?
Authors: Corthay A.
Published: July 2009

CD4+ T cells are commonly divided into regulatory T (Treg) cells and conventional T helper (Th) cells. Th cells control adaptive immunity against pathogens and cancer by activating other effector immune cells. Treg cells are defined as CD4+ T cells in charge of suppressing potentially deleterious activities of Th cells. This review briefly summarizes the current knowledge in the Treg field and defines some key questions that remain to be answered. Suggested functions for Treg cells include: prevention of autoimmune diseases by maintaining self‐tolerance; suppression of allergy, asthma and pathogen‐induced immunopathology; feto‐maternal tolerance; and oral tolerance. Identification of Treg cells remains problematic, because accumulating evidence suggests that all the presently‐used Treg markers (CD25, CTLA‐4, GITR, LAG‐3, CD127 and Foxp3) represent general T‐cell activation markers, rather than being truly Treg‐specific. Treg‐cell activation is antigen‐specific, which implies that suppressive activities of Treg cells are antigen‐dependent. It has been proposed that Treg cells would be self‐reactive, but extensive TCR repertoire analysis suggests that self‐reactivity may be the exception rather than the rule. The classification of Treg cells as a separate lineage remains controversial because the ability to suppress is not an exclusive Treg property. Suppressive activities attributed to Treg cells may in reality, at least in some experimental settings, be exerted by conventional Th cell subsets, such as Th1, Th2, Th17 and T follicular (Tfh) cells. Recent reports have also demonstrated that Foxp3+ Treg cells may differentiate in vivo into conventional effector Th cells, with or without concomitant downregulation of Foxp3.
Functional characterization of CCA1/LHY homolog genes, PpCCA1a and PpCCA1b, in the moss Physcomitrella patens
Authors: Okada Ryo , Kondo Sayo , Satbhai Santosh B. , Yamaguchi Nobutoshi , Tsukuda Masashi , Aoki Setsuyuki
Published: July 2009

The evolution of circadian clocks in land plants is not understood, because circadian rhythms have received little attention in plants other than angiosperms. We have characterized two genes, PpCCA1a and PpCCA1b, homologs of the Arabidopsis thaliana clock genes CCA1/LHY, from the moss Physcomitrella patens. PpCCA1a and PpCCA1b, together with angiosperm CCA1/LHY homologs, belong to the clock‐associated single‐myb gene family of green plants (including green algae and land plants). The accumulation of PpCCA1a and PpCCA1b mRNA showed rhythms with a period of approximately 1 day, phased as are those of angiosperm homologs, under 24 h light/dark cycles or in continuous dark. However, in marked contrast to angiosperm homologs, both genes showed arrhythmic profiles in continuous light. The timing of the PpCCA1b peak is determined by the time of the last light to dark transition, suggesting that the arrhythmicity in continuous light is due to dysfunction of the core clock. We generated single and double disruptants for PpCCA1a and PpCCA1b, and found that the double disruptants showed: (i) short periodicity and damped amplitude in the PpCCA1b rhythm, (ii) similar changes in the rhythmically expressed genes PpSIG5 and PpPRRa, and (iii) de‐repression of PpCCA1b transcription levels, indicating negative feedback regulation. These observations indicate that the two genes are not merely structural homologs but also functional counterparts of CCA1/LHY. Together, our results illustrate similarities as well as divergence of the clock machineries between P. patens and A. thaliana, two distantly placed species in land plant phylogeny.
Targeted metabolite and transcript profiling for elucidating enzyme function: isolation of novel N‐methyltransferases from three benzylisoquinoline alkaloid‐producing species
Authors: Liscombe David K. , Ziegler Jörg , Schmidt Jürgen , Ammer Christian , Facchini Peter J.
Published: July 2009

An integrated approach using targeted metabolite profiles and modest EST libraries each containing approximately 3500 unigenes was developed in order to discover and functionally characterize novel genes involved in plant‐specialized metabolism. EST databases have been established for benzylisoquinoline alkaloid‐producing cell cultures of Eschscholzia californica, Papaver bracteatum and Thalictrum flavum, and are a rich repository of alkaloid biosynthetic genes. ESI‐FTICR‐MS and ESI‐MS/MS analyses facilitated unambiguous identification and relative quantification of the alkaloids in each system. Manual integration of known and candidate biosynthetic genes in each EST library with benzylisoquinoline alkaloid biosynthetic networks assembled from empirical metabolite profiles allowed identification and functional characterization of four N‐methyltransferases (NMTs). One cDNA from T. flavum encoded pavine N‐methyltransferase (TfPavNMT), which showed a unique preference for (±)‐pavine and represents the first isolated enzyme involved in the pavine alkaloid branch pathway. Correlation of the occurrence of specific alkaloids, the complement of ESTs encoding known benzylisoquinoline alkaloid biosynthetic genes and the differential substrate range of characterized NMTs demonstrated the feasibility of bilaterally predicting enzyme function and species‐dependent specialized metabolite profiles.
Field evaluation of Crystal VC® Rapid Dipstick test for cholera during a cholera outbreak in Guinea‐Bissau
Authors: Harris Julie R. , Cavallaro Elizabeth C. , De Nóbrega Aglaêr A. , Dos S. Barrado Jean C. B. , Bopp Cheryl , Parsons Michele B. , Djalo Djulde , Fonseca Fatima G. da S. , Ba Umaro , Semedo Agostinho , Sobel Jeremy , Mintz Eric D.
Published: July 2009

Objectives  To evaluate performance characteristics and ease of use of the new commercially available Crystal VC® Rapid Dipstick (VC) test (Span Diagnostics, India) for Vibrio cholerae O1 and O139.

Methods  Whole stool was collected from patients presenting to a hospital cholera ward during a 2008 epidemic in Guinea‐Bissau. The VC test on stool samples was conducted on‐site; samples were subsequently stored in Cary‐Blair transport media and sent to the Centers for Disease Control and Prevention for diagnostic testing by culture and polymerase chain reaction (PCR). In addition, four local laboratory technicians who were unfamiliar with the test were provided with stool samples, the VC test kit, and simple written instructions and asked to perform the test and interpret results.

Results  A total of 101 stool specimens were collected and tested. Compared with PCR, the test was 97% sensitive and 71–76% specific. Laboratory technicians in Bissau performed the test and interpreted results correctly using only simple written instructions.

Conclusions  The VC test may be useful for cholera diagnosis in outbreak situations where laboratory capacity is limited.
Evaluation of interleukin‐6 and interleukin‐10 in lung transplant patients with human cytomegalovirus infection
Authors: Zedtwitz‐Liebenstein Konstantin , Jaksch Peter , Burgmann Heinz , Friehs Helmut , Hofbauer Roland , Schellongowski Peter , Frass Michael
Published: July 2009

Abstract:  We hypothesized that interleukin‐6 (IL‐6) in plasma and bronchoalveolar lavage (BAL) might serve as additional diagnostic parameter in lung transplant patients with human cytomegalovirus (HCMV) infection. Therefore, we compared IL‐6 levels in HCMV‐positive vs. HCMV‐negative patients. IL‐6 was measured by ELISA in plasma and BAL in 111 patients. Furthermore, we investigated the influence of IL‐10 on IL‐6 production in HCMV‐positive patients. For HCMV–DNA detection in plasma and BAL a quantitative polymerase chain reaction (PCR) assay was used. IL‐6 levels were significantly higher in the HCMV‐positive group (n = 39; BAL p = 0.045; plasma p = 0.017) in comparison to the HCMV‐negative group (n = 72). IL‐10 did not correlate with IL‐6 concentration (p = 0.146). Donor (D) or recipient (R) HCMV‐constellation did not influence IL‐6 concentration. IL‐6 levels were not influenced by elevated levels of HCMV copies. Our data suggest that IL‐6 does not serve as a good diagnostic parameter for existence of HCMV infection in lung transplant patients. Because of the wide range of the IL‐6 levels in both groups, we were not able to find a breakpoint differentiating between infected and not‐infected patients. Another important finding was that IL‐6 production is not dependent of the HCMV status of D/R.
Yield performances of japonica introgression lines selected for drought tolerance in a BC breeding programme
Authors: He Y. X. , Zheng T. Q. , Hao X. B. , Wang L. F. , Gao Y. M. , Hua Z. T. , Zhai H. Q. , Xu J. L. , Xu Z. J. , Zhu L. H. , Li Z. K.
Published: July 2009

With 5 tables

Developing drought tolerant cultivars is a preferred strategy to solve water‐shortage facing rice farmers. A backcross (BC) breeding was initiated to improve drought tolerance (DT) of japonica hybrids in North China using an elite japonica restorer, C418, as recipient and five indica cultivars as donors. A two‐round‐selection for yield under severe drought together with a two‐round‐selection for yield under irrigation resulted in 113 BC2F8 introgression lines (ILs). Progeny testing allowed the identification of 46 (40.7%) superior‐C418‐ILs that had significantly improved yield potential under water stress and/or normal irrigation, demonstrating the power of BC breeding in exploiting favourable variation hidden in the indica gene pool for improving complex traits of japonica rice. Increased height and accelerated‐heading were major phenotypic changes correlated with improved‐yield under stress in these ILs, suggesting the possible involvement of gibberellin (GA) pathway and drought escaping. Considerable variations in yield components among these ILs indicate the presence of different underlying mechanisms. The C418‐ILs developed in this study provide useful materials for dissecting DT and yield, and for further target‐trait‐improvement by pyramiding.
Northern Barbados accretionary prism: Structure, deformation, and fluid flow interpreted from 3D seismic and well‐log data
Authors: Cukur Deniz , Lee Gwang H. , Um Jeong G. , Kim Dae C. , Kim Jin H.
Published: July 2009

We reanalyzed 3D seismic reflection and logging‐while‐drilling data from the toe of the northern Barbados accretionary prism to interpret structure, deformation, and fluid flow related to subduction processes. The seafloor amplitude and coherence reveal an abrupt change in the thrust orientation from NNE at the thrust front and north and NNW about 5 km west of the thrust front. These thrust sets are separated by a triangular‐shaped quiet area, which may represent a zone of low strength. The northeast‐trending band of strong negative amplitude and high coherence in the décollement, known to be an interval of arrested consolidation, overlaps the quiet area, suggesting that the arrested consolidation may be related to the lack of thrust imbrication, and thus, vertical drainage for fluid in the accretionary prism. Fractal analysis of the décollement and top of the subducting oceanic basement indicates that the relief of the décollement correlates with the topography of the oceanic basement. Differential compaction of the underthrust sediment overlying the rugged oceanic basement, together with the basement faults that penetrate into the décollement probably caused relief or even faulting in the décollement.
Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes)
Authors: Spadella Maria Angélica , Oliveira Claudio , Quagio‐Grassiotto Irani
Published: July 2009

Spadella, M.A., Oliveira, C. and Quagio‐Grassiotto, I. 2009. Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes). —Acta Zoologica (Stockholm) 91: 373–389.

Siluriformes comprises the most diverse and widely distributed ostariophysan group, a fish assemblage that includes about three quarters of the freshwater fish of the world. In this study, the ultrastructural characterization of spermiogenesis and spermatozoa in specimens of Copionodontinae (the sister group to all other trichomycterids), Trichomycterinae (a derived trichomycterid group), and Ituglanis (a genus not assigned to any trichomycterid subfamily) is presented. The comparative analyses of the data show that trichomycterid species share six of seven analyzed spermiogenesis characters, reinforcing the monophyly of the group. Analyses of trichomycterid sperm ultrastructure showed that the species studied share the same character states for nine of seventeen characters analyzed. Copionodon orthiocarinatus and Ituglanis amazonicus each share more ultrastructural characters with species of Trichomycterus than with one another. Regarding the families of Loricarioidea, the species of Trichomycteridae share more characters of spermatogenesis, spermiogenesis, and sperm with representatives of the families Callichthyidae, Loricariidae, and Scoloplacidae than with Nematogenyidae, its hypothesized sister group. With the exception of the family Nematogenyidae, the character similarities observed reinforce the monophyly of the superfamily Loricarioidea.
The Role of Situational Interviews in Fostering Positive Reactions to Selection Decisions
Authors: Seijts Gerard H. , Kyei‐Poku Ivy
Published: July 2009

We investigated the effect of interview format and employment equity program strength on perceptions of fairness. We used job seekers and vignettes to test the hypotheses. The participants reported lukewarm support for employment equity programs. The use of a situational interview in the selection process of an organisation that had adopted an employment equity program contributed to higher perceptions of fairness vis‐à‐vis the use of an unstructured interview. The results also showed that the inclusion of a situational interview in the selection process mitigated negative reactions to the selection decision when a strong employment equity program was in place as well as when a female visible minority was hired.

Nous avons évalué l'impact sur la perception de justice du style d'entretien et de la rigueur d'une charte d'équité relative à l'emploi. On a fait appel à des demandeurs d'emploi et utilisé un test de jugement situationnel pour éprouver les hypothèses. Les répondants se sont montrés peu enthousiastes en ce qui concerne les chartes d'équité relatives à l'emploi. Le choix d'un entretien structuré dans le processus de sélection d'une organisation qui avait adopté une charte d'équité relative à l'emploi a amélioré la perception de justice portant sur un entretien ordinaire. Il apparaît aussi que la présence d'un entretien structuré dans le processus de sélection atténuait les réactions négatives consécutives au résultat de la sélection quand existait une sérieuse charte d'équité relative à l'emploi et quand était embauchée une minorité féminine non négligeable.
Longitudinal Study of Bladder Cancer with Cytology and Biopsy
Authors: LOENING S. , NARAYANA A. , YODER L. , SLYMEN D. , WEINSTEIN S. , PENICK G. , CULP D.
Published: July 2009

Summary— A study of urinary cytology and selected mucosal biopsies in conjunction with cystoscopy provided additional information of value in the management of 318 patients with bladder cancer. These procedures were especially helpful in patients with no visible lesion on follow‐up cystoscopies in assessing the bladder epithelium, the behaviour of which may be unpredictable in that no further tumours may occur, or they may arise at irregular intervals.
Differences in the free Ca2+ in undiluted urine from stone formers and normal subjects using a new generation of ion‐selective electrodes
Authors: Langley S.E.M. , Fry C.H.
Published: July 2009

Objectives To measure the ionized Ca2+ in urine from normal subjects and patients with urinary tract stones.

Patients and methods Urine samples were obtained from 37 normal subjects and 52 stone‐formers. Ca2+ was measured using plastic dip‐cast ion‐selective electrodes; total Ca and other variables were measured by standard analytical techniques.

Results The ionized Ca2+ and the total Ca were greater in stone‐formers' urine although the difference was more significant with the Ca2+ data, especially at a standardized pH. Absolute values of the Ca2+ were dependent on the type of reference electrode used. The Ca2+ was a function of urine pH; lower values were recorded as pH increased. Measured values of the Ca2+ did not correlate well with calculated values using a standard computer program.

Conclusions Measurement of the Ca2+ in spot urine samples at a standard pH provides a more discriminative test than total Ca for the presence of urinary tract stones. The pH dependence of the Ca2+ may have important consequences in the formation of urinary tract stones. The poor correlation between measured and computed values of Ca2+ emphasizes the importance of accurate measurement of this variable.
pEAQ: versatile expression vectors for easy and quick transient expression of heterologous proteins in plants
Authors: Sainsbury Frank , Thuenemann Eva C. , Lomonossoff George P.
Published: July 2009

Agro‐infiltration of leaf tissue with binary vectors harbouring a sequence of interest is a rapid method of expressing proteins in plants. It has recently been shown that flanking the sequence to be expressed with a modified 5′‐untranslated region (UTR) and the 3′‐UTR from Cowpea mosaic virus (CPMV) RNA‐2 (CPMV‐HT) within the binary vector pBINPLUS greatly enhances the level of expression that can be achieved [Sainsbury, F. and Lomonossoff, G.P. (2008)Plant Physiol. 148, 1212–1218]. To exploit this finding, a series of small binary vectors tailored for transient expression (termed the pEAQ vectors) has been created. In these, more than 7 kb of non‐essential sequence was removed from the pBINPLUS backbone and T‐DNA region, and unique restriction sites were introduced to allow for accommodation of multiple expression cassettes, including that for a suppressor of silencing, on the same plasmid. These vectors allow the high‐level simultaneous expression of multiple polypeptides from a single plasmid within a few days. Furthermore, vectors have been developed which allow the direct cloning of genes into the binary plasmid by both restriction enzyme‐based cloning and GATEWAY recombination. In both cases, N‐ or C‐terminal histidine tags may be fused to the target sequence as required. These vectors provide an easy and quick tool for the production of milligram quantities of recombinant proteins from plants with standard plant research techniques at a bench‐top scale.