bluuebunny/crossref_metadata_2025 huggingface dataset:
Target selection of proprioceptive and motor axon synapses on neonatal V1‐derived Ia inhibitory interneurons and Renshaw cells
Authors: Siembab Valerie C. , Smith Courtney A. , Zagoraiou Laskaro , Berrocal Maria C. , Mentis George Z. , Alvarez Francisco J.
Published: June 2010

The diversity of premotor interneurons in the mammalian spinal cord is generated from a few phylogenetically conserved embryonic classes of interneurons (V0, V1, V2, V3). Their mechanisms of diversification remain unresolved, although these are clearly important to understand motor circuit assembly in the spinal cord. Some Ia inhibitory interneurons (IaINs) and all Renshaw cells (RCs) derive from embryonic V1 interneurons; however, in adult they display distinct functional properties and synaptic inputs, for example proprioceptive inputs preferentially target IaINs, while motor axons target RCs. Previously, we found that both inputs converge on RCs in neonates, raising the possibility that proprioceptive (VGLUT1‐positive) and motor axon synapses (VAChT‐positive) initially target several different V1 interneurons populations and then become selected or deselected postnatally. Alternatively, specific inputs might precisely connect only with predefined groups of V1 interneurons. To test these hypotheses we analyzed synaptic development on V1‐derived IaINs and compared them to RCs of the same age and spinal cord levels. V1‐interneurons were labeled using genetically encoded lineage markers in mice. The results show that although neonatal V1‐derived IaINs and RCs are competent to receive proprioceptive synapses, these synapses preferentially target the proximal somato‐dendritic regions of IaINs and postnatally proliferate on IaINs, but not on RCs. In contrast, cholinergic synapses on RCs are specifically derived from motor axons, while on IaINs they originate from Pitx2 V0c interneurons. Thus, motor, proprioceptive, and even some interneuron inputs are biased toward specific subtypes of V1‐interneurons. Postnatal strengthening of these inputs is later superimposed on this initial preferential targeting. J. Comp. Neurol. 518:4675–4701, 2010. © 2010 Wiley‐Liss, Inc.
Expression of neuronal markers, synaptic proteins, and glutamine synthetase in the control and regenerating lizard visual system
Authors: Romero‐Alemán M.M. , Monzón‐Mayor M. , Santos E. , Yanes C.
Published: June 2010

Spontaneous regrowth of retinal ganglion cell (RGC) axons occurs after optic nerve (ON) transection in the lizard Gallotia galloti. To gain more insight into this event we performed an immunohistochemical study on selected neuron and glial markers, which proved useful for analyzing the axonal regrowth process in different regeneration models. In the control lizards, RGCs were beta‐III tubulin‐ (Tuj1) and HuCD‐positive. The vesicular glutamate transporter‐1 (VGLUT1) preferentially stained RGCs and glial somata rather than synaptic layers. In contrast, SV2 and vesicular GABA/glycine transporter (VGAT) labeling was restricted to both plexiform layers. Strikingly, the strong expression of glutamine synthetase (GS) in both Müller glia processes and macroglial somata revealed a high glutamate metabolism along the visual system. Upregulation of Tuj1 and HuCD in the surviving RGCs was observed at all the timepoints studied (1, 3, 6, 9, and 12 months postlesion). The significant rise of Tuj1 in the optic nerve head and optic tract (OTr) by 1 and 6 months postlesion, respectively, suggests an increase of the beta‐III tubulin transport and incorporation into newly formed axons. Persistent Tuj1+ and SV2+ puncta and swellings were abnormally observed in putative degenerating/dystrophic fibers. Unexpectedly, neuron‐like cells of obscure significance were identified in the control and regenerating ON‐OTr. We conclude that: 1) the persistent upregulation of Tuj1 and HuCD favors the long‐lasting axonal regrowth process; 2) the latter succeeded despite the ectopia and dystrophy of some regrowing fibers; and 3) maintenance of the glutamate‐glutamine cycle contributes to the homeostasis and plasticity of the system. J. Comp. Neurol. 518:4067–4087, 2010. © 2010 Wiley‐Liss, Inc.
Injectable supramolecular hybrid hydrogels formed by MWNT‐grafted‐poly(ethylene glycol) and α‐cyclodextrin
Authors: Sui Kunyan , Gao Song , Wu Wenwen , Xia Yanzhi
Published: June 2010

Poly(ethylene glycol)‐grafted‐multiwalled carbon nanotube (MWNT‐g‐PEG) was synthesized by a coupling reaction and formed inclusion complexes (ICs) after selective threading of the PEG segment of the MWNT‐g‐PEG through the cavities of α‐cyclodextrins (α‐CDs) units. The polypseudorotaxane structures of the as‐obtained hydrogels were confirmed by 1H NMR, X‐ray diffraction and DSC analyses. The complexation of the PEG segments with α‐CDs and the hydrophobic interaction between the MWNT resulted in the formation of supramolecular hybrid hydrogels with a strong network. Thermal analysis showed that the thermal stability of the hydrogel was substantially improved by up to 100 °C higher than that of native hydrogel. The resultant hybrid hydrogels were found to be thixotropic and reversible, and could be applied as a promising injectable drug delivery system. The mechanical strength of the hybrid hydrogels was greatly improved in comparison with that of the corresponding native hydrogels. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3145–3151, 2010
Slug inhibits proliferation of human prostate cancer cells via downregulation of cyclin D1 expression
Authors: Liu Jun , Uygur Berna , Zhang Zhonghui , Shao Lijian , Romero Diana , Vary Calvin , Ding Qiang , Wu Wen‐Shu
Published: June 2010

BACKGROUND

Slug is a transcription factor of the Snail/Slug zinc‐finger family and is implicated in metastasis of tumors, but its role in cell proliferation of prostate cancers is unclear.

METHODS

Expression level of Slug and other genes was examined by Western blot, RT‐PCR, and QPCR analyses. The forced expression of Slug was mediated by retroviruses and adenoviruses. Slug was downregulated by shRNA. Cell growth was measured by the MTT assay and the quick cell proliferation assay.

RESULTS

Here, we demonstrated that Slug expression is elevated in mouse prostate tumors, and human prostate cancer cell lines LNCaP, PC‐3, and 22RV1. Forced expression of Slug‐inhibited proliferation of prostate cancer cells PC‐3 and DU‐145. Conversely, reduced expression of Slug by shRNA promoted growth of PC‐3 cancer cells. Consistent with these data, we found that forced expression of Slug in prostate cancer cells led to G1 cell‐cycle arrest. Furthermore, ectopic expression of Slug decreased cyclin D1 expression in both PC‐3 and DU‐145 cells, and knockdown of Slug by shRNA upregulated cyclin D1 expression in these cancer cells. In addition, we demonstrated that ectopic expression of cyclin D1 relieved Slug‐mediated inhibition of proliferation of prostate cancer cells.

CONCLUSIONS

We provide the first compelling evidence that Slug is a negative regulator of proliferation of prostate cancer cells. Our findings in this study are distinct from the previously reported role of Slug as a promoter for tumor metastasis, and suggest that Slug is a prognostic marker and potential therapeutic target. Prostate 70: 1768–1777, 2010. © 2010 Wiley‐Liss, Inc.
Synthesis of Structured Phosphatidylcholine Containing n‐3 PUFA Residues via Acidolysis Mediated by Immobilized Phospholipase A1
Authors: Kim In‐Hwan , Garcia Hugo S. , Hill Charles G.
Published: June 2010

Structured phosphatidylcholine (PC) was successfully synthesized by acidolysis of PC derived from soybean with n‐3 polyunsaturated fatty acids (PUFA) obtained from fish oil using an immobilized phospholipase‐A1 from Thermomyces lanuginosus/Fusarium oxysporum as the biocatalyst. The effect of water activity in the range from 0.43 to 0.93 on n‐3 PUFA residue content was investigated. The immobilized phospholipase was more active at water activities greater than 0.53. The yield of PC decreased as the water activity increased from 0.43 to 0.93. The yield of lysophosphatidylcholine (LPC) increased significantly during the first 4 h of reaction as a consequence of hydrolysis of the PC. As the enzyme loading increased, the proportion of n‐3 PUFA residues in the PC and LPC present at various times in the mixture of these species increased to as much as 15% of the total weight of substrate. For all enzyme loadings tested, both the proportion of n‐3 PUFA residues in the total PC (unreacted and modified) and the production of LPC increased significantly when the reaction time was increased, although differences in n‐3 PUFA content were observed. When both the n‐3 PUFA content of the PC and the total yield of PC are considered, the optimum water activity and enzyme loading for production of structured PC and LPC are 0.65 and 15%, respectively.
Host mortality and variability in epizootics of Schistocephalus solidus infecting the threespine stickleback, Gasterosteus aculeatus
Authors: HEINS D. C. , BIRDEN E. L. , BAKER J. A.
Published: June 2010

An analysis of the metrics of Schistocephalus solidus infection of the threespine stickleback, Gasterosteus aculeatus, in Walby Lake, Alaska, showed that an epizootic ended between 1996 and 1998 and another occurred between 1998 and 2003. The end of the first epizootic was associated with a crash in population size of the stickleback, which serves as the second intermediate host. The likely cause of the end of that epizootic is mass mortality of host fish over winter in 1996–1997. The deleterious impact of the parasite on host reproduction and increased host predation associated with parasitic manipulation of host behaviour and morphology to facilitate transmission might also have played a role, along with unknown environmental factors acting on heavily infected fish or fish in poor condition. The second epizootic was linked to relatively high levels of prevalence and mean intensity of infection, but parasite:host mass ratios were quite low at the peak and there were no apparent mass deaths of the host. A number of abiotic and biotic factors are likely to interact to contribute to the occurrence of epizootics in S. solidus, which appear to be unstable and variable. Epizootics appear to depend on particular and, at times, rare sets of circumstances.
Partitions by congruent sets and optimal positions
Authors: XUE YU-MEI , KAMAE TETURO
Published: June 2010

Let X be a metrizable space with a continuous group or semi-group action G. Let D be a non-empty subset of X. Our problem is how to choose a fixed number of sets in {g−1D; g∈G}, say σ−1D with σ∈τ, to maximize the cardinality of the partition ℙ({σ−1D; σ∈τ}) generated by them. Let An infinite subset Σ of G is called an optimal position of the triple (X,G,D) if holds for any k=1,2,… and τ⊂Σ with #τ=k. In this paper, we discuss examples of the triple (X,G,D) admitting or not admitting an optimal position. Let X=G=ℝn  (n≥1) , where the action g∈G to x∈X is the translation x−g. If D is the n-dimensional unit ball, then holds and the triple (X,G,D) admits an optimal position. In fact, if n≥2 and Σ is an infinite subset of G such that for some δ with 0<δ<1 , Σ⊂{x∈ℝn ; ‖x‖=δ}, and that any subset of Σ with cardinality n+1 is not on a hyperplane, then Σ is an optimal position of the triple (X,G,D) . We have determined the primitive factor of the uniform sets coming from these optimal positions. We also show that in the above setting with n=2 and the unit square D′ in place of the unit disk D, the maximal pattern complexity is unchanged and p*X,G,D′(k)=k2 −k+2 , but there is no optimal position.
Detection of small lunar secondary craters in circular polarization ratio radar images
Authors: Wells Kassandra S. , Campbell Donald B. , Campbell Bruce A. , Carter Lynn M.
Published: June 2010

The identification of small (D < a few kilometers) secondary craters and their global distributions are of critical importance to improving our knowledge of surface ages in the solar system. We investigate a technique by which small, distal secondary craters can be discerned from the surrounding primary population of equivalent size based on asymmetries in their ejecta blankets. The asymmetric ejecta blankets are visible in radar circular polarization ratio (CPR) but not as optical albedo features. Measurements with our new technique reveal 94 secondary craters on the Newton and Newton‐A crater floors near the lunar south pole. These regions are not in an obvious optical ray, but the orientation of asymmetric secondary ejecta blankets suggests that they represent an extension of the Tycho crater ray that crosses Clavius crater. Including the secondary craters at Newton and Newton‐A skews the terrain age inferred by crater counts. It is reduced by few percentages by their removal, from 3.8 to 3.75 Gyr at Newton‐A. Because “hidden rays” like that identified here may also occur beyond the edges of other optically bright lunar crater rays, we assess the effect that similar but hypothetical populations would have on lunar terrains of various ages. The average secondary crater density measured at 1 km diameter is equivalent to the crater density at 1 km on a 3.4 Gyr surface [Neukum et al., 2001]. Younger surfaces (i.e., younger crater ejecta blankets) would be dominated by secondary craters below 1 km if superposed by a hidden ray.
Controls on mangrove forest‐atmosphere carbon dioxide exchanges in western Everglades National Park
Authors: Barr Jordan G. , Engel Vic , Fuentes José D. , Zieman Joseph C. , O'Halloran Thomas L. , Smith Thomas J. , Anderson Gordon H.
Published: June 2010

We report on net ecosystem production (NEP) and key environmental controls on net ecosystem exchange (NEE) of carbon dioxide (CO2) between a mangrove forest and the atmosphere in the coastal Florida Everglades. An eddy covariance system deployed above the canopy was used to determine NEE during January 2004 through August 2005. Maximum daytime NEE ranged from −20 to −25 μmol (CO2) m−2 s−1 between March and May. Respiration (Rd) was highly variable (2.81 ± 2.41 μmol (CO2) m−2 s−1), reaching peak values during the summer wet season. During the winter dry season, forest CO2 assimilation increased with the proportion of diffuse solar irradiance in response to greater radiative transfer in the forest canopy. Surface water salinity and tidal activity were also important controls on NEE. Daily light use efficiency was reduced at high (>34 parts per thousand (ppt)) compared to low (<17 ppt) salinity by 46%. Tidal inundation lowered daytime Rd by ∼0.9 μmol (CO2) m−2 s−1 and nighttime Rd by ∼0.5 μmol (CO2) m−2 s−1. The forest was a sink for atmospheric CO2, with an annual NEP of 1170 ± 127 g C m−2 during 2004. This unusually high NEP was attributed to year‐round productivity and low ecosystem respiration which reached a maximum of only 3 g C m−2 d−1. Tidal export of dissolved inorganic carbon derived from belowground respiration likely lowered the estimates of mangrove forest respiration. These results suggest that carbon balance in mangrove coastal systems will change in response to variable salinity and inundation patterns, possibly resulting from secular sea level rise and climate change.
Influence of the solar cycle and QBO modulation on the Southern Annular Mode
Authors: Kuroda Yuhji , Yamazaki Koji
Published: June 2010

Influence of the 11‐year solar cycle and the stratospheric equatorial Quasi‐Biennial Oscillation (QBO) on the Southern Annular Mode (SAM) in late winter/spring is examined through the analysis of combined reanalysis data of ECMWF. It is found that the signal is strongly affected by both the solar cycle and the QBO. Regarding the effect of the solar cycle, the signal extends to the upper stratosphere and persists into the following summer in years with high solar activity, but it is restricted to the troposphere and disappears very quickly in years with low solar activity. For the QBO, the signal extends to the upper stratosphere in late winter/spring but disappears in the following summer in QBO‐west years. On the other hand, the signal extends vertically as the time evolution and tends to persist into the following summer in QBO‐east years. When both the solar cycle and the QBO are considered, the effects from the solar cycle dominate and those from the QBO work as linearly superimposed factors. Role of ozone on the solar cycle and QBO modulation is also discussed.
Sphingosylphosphorylcholine is a Proinflammatory Mediator in Cerebral Arteries
Authors: Wirrig Christiane , Hunter Irene , Mathieson Fiona A , Nixon Graeme F
Published: June 2010

Inflammation has an important function in the development of cerebral vasospasm after subarachnoid hemorrhage (SAH); however, the mediators of this inflammatory response have not been clearly identified. In this study, we have investigated the potential function of two sphingolipids, which occur naturally in plasma and serum, sphingosylphosphorylcholine (SPC) and sphingosine 1-phosphate (S1P), to act as proinflammatory mediators in cerebral artery vascular smooth muscle (VSM) cells. In rat cerebral arteries, SPC but not S1P activated p38 mitogen-activated protein kinase (MAPK). Using transcription factor arrays, two proinflammatory transcription factors activated by SPC in cerebral arteries were identified—nuclear factor-κB and CCAAT-enhancer-binding protein. Both these transcription factors were activated by SPC in a p38MAPK-dependent manner. To determine whether this contributed to vascular inflammation, an inflammatory protein array was performed, which showed that SPC increased release of the chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured rat VSM cells. This increase in MCP-1 expression was confirmed in cerebral arteries. The S1P did not increase MCP-1 release. Taken together, our results suggest that SPC, but not S1P, can act as a proinflammatory mediator in cerebral arteries. This may contribute to inflammation observed after SAH and may be part of the initiating event in vasospasm.
Abdominal massage for people with constipation: a cost utility analysis
Authors: Lämås Kristina , Lindholm Lars , Engström Birgitta , Jacobsson Catrine
Published: June 2010

lämås k., lindholm l., engström b. & jacobsson c. (2010) Abdominal massage for people with constipation: a cost utility analysis. Journal of Advanced Nursing 66(8), 1719–1729.

Title.  Abdominal massage for people with constipation: a cost utility analysis.

Aim.  This paper is a report of a study conducted to evaluate change in health‐related quality of life for people with constipation receiving abdominal massage and to estimate the cost‐effectiveness of two alternative scenarios developed from the original trial.

Background.  Constipation is a common problem and is associated with decrease in quality of life. Abdominal massage appears to decrease the severity of gastrointestinal symptoms, but its impact on health‐related quality of life has not been assessed.

Methods.  A randomized controlled trial including 60 participants was conducted in Sweden between 2005 and 2007. The control group continued using laxatives as before and the intervention group received additional abdominal massage. Health‐related quality of life was assessed using the EQ‐5D and analyzed with linear regression. Two scenarios were outlined to conduct a cost utility analysis. In the self‐massage scenario patients learned to give self‐massage, and in the professional massage scenario patients in hospital received abdominal massage from an Enrolled Nurse.

Results.  Linear regression analysis showed that health‐related quality of life was statistically significantly increased after 8 weeks of abdominal massage. About 40% were estimated to receive good effect. For ‘self‐massage’, the cost per quality adjusted life year was €75,000 for the first 16 weeks. For every additional week of abdominal massage, the average dropped and eventually approached €8300. For ‘professional massage’, the cost per quality adjusted life year was €60,000 and eventually dropped to €28,000.

Conclusion.  Abdominal massage may be cost‐effective in the long‐term and it is relevant to consider it when managing constipation. A crucial aspect will be to identify those who will benefit.
Effects of saliva substitutes on oral status in patients with Type 2 diabetes
Authors: Montaldo L. , Montaldo P. , Papa A. , Caramico N. , Toro G.
Published: June 2010

Diabet. Med. 27, 1280–1283 (2010)

Aims  To assess oral status in a sample of Type 2 diabetic patients before and after therapy with saliva substitutes and oral status in a control group of diabetic patients who were not given saliva substitutes.

Methods  Salivary flow rate was determined in 134 patients (mean age 47.9 ± 2.9 years) with Type 2 diabetes. Mean salivary rate was significantly low compared with a healthy control group. The sample of 134 patients was randomly divided into two groups of 67 people each. One group was given immunologically active salivary substitutes for 6 months, the other group was given nothing. Each patient of the two groups underwent a dental and periodontal examination at the beginning of the study and 6 months later.

Results  As regards carious teeth and teeth loss, there was no statistical difference between the first group after 6 months of treatment with salivary substitutes and the control group (P > 0.01). Salivary substitutes did not significantly reduce the periodontal disease (P > 0.01). In the group treated with salivary substitutes, after 6 months of therapy, the average dental plaque index decreased from 2.3 ± 0.73 to 1.6 ± 0.56, patients with gingivitis decreased from 66 to 43% and patients with positive yeast counts decreased from 60 to 37%. These differences were statistically significant (P < 0.01).

Conclusions  In Type 2 diabetes, in the case of hyposalivation, a therapy with immunologically active saliva substitutes can be of help in reducing the amount of plaque, gingivitis and positive yeast counts.
Evolutionary breakdown of pollination specialization in a Caribbean plant radiation
Authors: Martén‐Rodríguez Silvana , Fenster Charles B. , Agnarsson Ingi , Skog Laurence E. , Zimmer Elizabeth A.
Published: June 2010

Featured paper: See Commentary p303
Low‐Temperature Sintering and Electrical Properties of ZnO–Bi2O3–TiO2–Co2O3–MnCO3‐Based Varistor with Bi2O3–B2O3 Frit for Multilayer Chip Varistor Applications
Authors: Wan Shuai , Lu Wenzhong , Wang Xiaochuan
Published: June 2010

The effects of a Bi2O3–B2O3 frit (denoted as BiBF) on the densification, phase transformation, microstructure, and nonlinear electrical properties of ZnO–Bi2O3–TiO2–Co2O3–MnCO3 (ZBTCM)‐based varistors have been investigated. The varistor ceramic with the addition of >2 wt% BiBF can be sintered at 900°C and 96.3% of the theoretical density was achieved. SEM revealed that the microstructure of the varistor ceramics with 2 wt% BiBF is uniform, with an average grain size of 13.5 μm. No porosity is observed. The typical ZnO–Bi2O3–TiO2‐based varistor phase compositions were detected for all varistor ceramics but the formation of a secondary phase, Bi4B2O9, became apparent when 4 wt% BiBF was added. The Bi4B2O9 phase crystallized from the Bi2O3–B2O3 frit, acting as a potential barrier at the grain boundary, increases the density of interface states Ns, barrier height Φb, and plays an important role in improving the electrical properties of the varistor ceramics. However, a large amount will be detrimental. Optimum properties were exhibited for the varistor ceramics with 2 wt% BiBF sintered at 900°C, with E1 mA=124.9 V/mm, α=46.2, and JL=0.2 μA/cm2. The reactivity of the varistor ceramic with Ag was also studied. The excellent electrical properties and low sintering temperature, coupled with chemical compatibility with Ag, suggest that Bi2O3–B2O3 frit sintering aids for ZnO–Bi2O3–TiO2–Co2O3–MnCO3 (ZBTCM)‐based varistors have great potential for using the base metal Ag as inner electrodes for low‐voltage MLV fabrication.
Measurement of skeletal muscle collagen breakdown by microdialysis
Authors: Miller B. F. , Ellis D. , Robinson M. M. , Rivera J. D. , Kjaer M. , Langberg H.
Published: June 2010

Exercise increases the synthesis of collagen in the extracellular matrix of skeletal muscle. Breakdown of skeletal muscle collagen has not yet been determined because of technical limitations. The purpose of the present study was to use local sampling to determine skeletal muscle collagen breakdown. Microdialysis fibers were testedin vitroto predict bath hydroxyproline (OHP) concentrations. We used anN‐methyl‐N‐[tert‐butyldimethyl‐silyl]trifluoroacetimide derivative to analyze OHP using gas chromatography–mass spectroscopy (GC–MS) and compared the results with a colorimetric OHP assay. Ten young, healthy male subjects performed a bout of resistance exercise with one leg, followed 17–21 h later byin vivoskeletal muscle sampling by microdialysis in exercised (EX) and control (CON) legs. Microdialysis reliably predicted [OHP]in vitro(R2=0.90). Analysis with GC–MS was strongly correlated to traditional analysis methods (CON: slope=1.03,R2=0.896, andP<0.05, EX: slope=0.795,R2=0.896, andP<0.05). We conclude thatin vitro, microdialysis fibers were able to measure OHP concentrations and were sensitive to changes in concentrations, a strenuous bout of exercise did not increase skeletal muscle collagen breakdown 17–21 h post‐exercise, and our measurement of OHP using GC–MS was in agreement with traditional assays.
Reexamining the Dominance of Birth Cohort Effects on Mortality
Authors: Murphy Michael
Published: June 2010

The association between birth cohort and subsequent mortality has been of interest especially following publication of studies around 1930 of cohorts born up to the latter part of the nineteenth century, particularly for England and Wales. Updated results are presented for this population, together with those for two other cohorts, twentieth‐century Japanese and British populations born about 1930, which have been identified as having particularly clear‐cut birth cohort patterns, and which are used to underpin incorporation of cohort effects in both British official and actuarial mortality forecasts. Graphical methods used to identify cohort patterns are discussed. A number of limitations and difficulties are identified that mean that the conclusions about the predominance of cohort effects are less robust than often assumed. It is argued that alternative explanations should be considered and that the concentration on birth cohorts with particularly advantaged patterns may distort research priorities.
Evaluation of Protein Extraction Methods for Vitis vinifera Leaf and Root Proteome Analysis by Two‐Dimensional Electrophoresis
Authors: Jellouli Neila , Salem Asma Ben , Ghorbel Abdelwahed , Jouira Hatem Ben
Published: June 2010

An efficient protein extraction method is crucial to ensure successful separation by two‐dimensional electrophoresis (2‐DE) for recalcitrant plant species, in particular for grapevine (Vitis vinifera L.). Trichloroacetic acid‐acetone (TCA‐acetone) and phenol extraction methods were evaluated for proteome analysis of leaves and roots from the Tunisian cultivar ‘Razegui’. The phenol‐based protocol proved to give a higher protein yield, a greater spot resolution, and a minimal streaking on 2‐DE gels for both leaf and root tissues compared with the TCA‐based protocol. Furthermore, the highest numbers of detected proteins on 2‐DE gels were observed using the phenol extraction from leaves and roots as compared with TCA‐acetone extraction.
Bidirectional Electron Transfer in the Reaction Centre of Photosystem I
Authors: Santabarbara Stefano , Galuppini Luca , Casazza Anna Paola
Published: June 2010

In the past decade light‐induced electron transfer reactions in photosystem I have been the subject of intensive investigations that have led to the elucidation of some unique characteristics, the most striking of which is the existence of two parallel, functional, redox active cofactors chains. This process is generally referred to as bidirectional electron transfer. Here we present a review of the principal evidences that have led to the uncovering of bidirectionality in the reaction centre of photosystem I. A special focus is dedicated to the results obtained combining time‐resolved spectroscopic techniques, either difference absorption or electron paramagnetic resonance, with molecular genetics, which allows, through modification of the binding of redox active cofactors with the reaction centre subunits, an effect on their physical‐chemical properties.
The peculiar dust shell of Nova DZ Cru (2003)
Authors: Evans A. , Gehrz R. D. , Woodward C. E. , Helton L. A. , Rushton M. T. , Bode M. F. , Krautter J. , Lyke J. , Lynch D. K. , Ness J.-U. , Starrfield S. , Truran J. W. , Wagner R. M.
Published: June 2010

We present Spitzer Space Telescope observations of the ‘peculiar variable’ DZ Cru, identified by Rushton et al. as a classical nova. A dust shell, on which are superimposed a number of features, is prominent in the 5–35μm range some 4 yr after eruption. We suggest that the dust in DZ Cru is primarily hydrogenated amorphous carbon in which aliphatic bands currently predominate and which may become either predominantly aromatic as the dust is photoprocessed by ultraviolet radiation from the stellar remnant or more likely completely destroyed.
Interlaboratory variability of CD34+ stem cell enumeration. A pilot study to national external quality assessment within the Czech Republic
Authors: LYSÁK D. , KALINA T. , MARTÍNEK J. , PIKALOVÁ Z. , VOKURKOVÁ D. , JAREŠOVÁ M. , MARINOV I. , ONDREJKOVÁ A. , ŠPAČEK M. , STEHLÍKOVÁ O.
Published: June 2010

We present the results of a pilot study concerning the interlaboratory variability of CD34+ enumeration. Three surveys, each including a set of samples, were sent to participating Czech flow cytometry laboratories. The efficacy of this exercise was determined by the reduction in interlaboratory variation and the influence of method used on assay outcome. The variability in results of CD34+ enumeration declined with time. The mean coefficient of variation (CV) of measurement among laboratories dropped, from 58% in first survey to 32% in last survey. All tested variables (gating strategy, platform methodology, sample preparation) affected the variability of the assay. Sample preparation method was associated with a significant bias of absolute CD34+ cell counts. Initially, the outcome of the measurement was also affected by the participating laboratory (identified by a unique laboratory number; ULN). However, laboratories with poorer performance modified their protocols during the study, and the ULN ceased to influence the variability. This study was successful in reducing the interinstitutional variability of CD34+ enumeration. It was shown that the implementation of a standardized protocol does not guarantee accurate measurement. Our research design represents a useful tool, which allows verification of the proper use of a standardized method, the training of operators and feedback in response to the survey results.
Genotype-Specific Clearance of Genital Human Papillomavirus (HPV) Infections among Mothers in the Finnish Family HPV Study
Authors: Louvanto Karolina , Syrjänen Kari J. , Rintala Marjut A. M. , Grénman Seija E. , Syrjänen Stina M.
Published: June 2010

The majority of cervical human papillomavirus (HPV) infections in young women are transient, but whether the clearance differs among different HPV genotypes and the different factors predicting genotype-specific clearance are partly unknown. In the Finnish Family HPV Study, 131 of 252 women (mean age, 25.5 years) cleared their infection during the prospective follow-up of 6 years (median, 62.4 months; range, 1.6 to 94.5 months). Cervical scrapings collected at each visit were tested for 24 low-risk and high-risk (HR) HPV types with multiplex HPV genotyping. Poison regression (panel data) was used to estimate predictors for the clearance of species 7 and 9 HPV genotypes. Of all HPV genotypes detected in these women, multiple-type and HPV type 16 (HPV16) infections showed clearance least frequently (46.1% and 50.5%, respectively). The actuarial and crude mean times to first clearance were variable among different genotypes. The actuarial clearance rate (events/person-time at risk) was highest for HPV16 and multiple-type infections, while HPV66 and -82 had the highest crude clearance rate. Independent predictors increasing type-specific clearance of species 7/9 HPV genotypes were older age (incidence rate ratio [IRR] = 1.1; 95% confidence interval [95% CI], 1.03 to 1.18;
P
= 0.002) and baseline oral HR HPV DNA-negative status (IRR = 2.94; 95% CI, 1.03 to 8.36;
P
= 0.042), while a higher number of sexual partners during the follow-up decreased the probability of clearance (IIR = 0.35; 95% CI, 0.15 to 0.83;
P
= 0.018). To conclude, HPV16 and multiple-type infections showed the lowest clearance among young mothers. Increasing age and negative oral HR HPV DNA status at baseline were associated with increased clearance, whereas a higher number of current sexual partners decreased the probability of species 7/9 HPV genotype clearance.
The first passage time to the equilibrium state of a first order reaction
Authors: Šolc Milan
Published: June 2010

The first passage time to the state of exact equilibrium (the most probable stationary state) for a first order reaction is described in terms of the probability density and the first and second moments. For large systems, the first moment is proportional to the logarithm of the number of particles in the system, while the dispersion is independent of the size of the system.
Characteristics for evaluating the reactor regime with endothermic reversible reaction
Authors: Horák Josef , Valášková Zina
Published: June 2010

Criteria are proposed in the paper for evaluating the reactor regime (with endothermic reversible reaction, heated by radiation of combustion products) from thermodynamic and kinetic points of view. The limiting reactor regimes in which the controlling process is the process kinetics or the heat transfer are defined. The effect of the catalyst activity on the reactor output and the surface temperature of the reaction tube and the effect of heat input power of the reactor radiation section on the conversion and the surface temperature of the tube are discussed. The results are verified on a simplified mathematical model of steam reforming and employed to discuss the selection of the regime of an industrial reactor.
Hydrogenation of cinnamyl methyl ether and allylbenzene on palladium catalysts
Authors: Červený Libor , Paseka Ivo , Fialová Eva , Růžička Vlastimil
Published: June 2010

The hydrogenation of cinnamyl methyl ether and allylbenzene in hexane and acetone at 20 °C and atmospheric pressure of hydrogen has been studied on eight palladium catalysts. The hydrogenation of cinnamyl methyl ether is accompanied by C-O bond splitting giving rise to propylbenzene and methanol, the hydrogenation of allylbenzene is associated with the isomerization of the double bond resulting in its conjugation with the benzene ring. A marked solvent effect on the selectivity of hydrogenation of cinnamyl methyl ether has been observed and ascribed to the effect of solvated protons on the adsorbed molecules of the ether which is promoted by polar medium. The solvent effect on the isomerization of allylbenzene during the hydrogenation is little pronounced, which suggests that this reaction is not of ionic nature.
Evaluation of polydispersity index Mw/Mn by quasielastic light scattering
Authors: Štěpánek Petr , Tuzar Zdeněk , Koňák Čestmír
Published: June 2010

The response of quasielastic light scattering to the polydispersity of scattering objects has been investigated. A new method of the polydispersity index determination has been suggested, suitable for the range 1.02 ⪬ Mw/Mn ⪬ 2.0 and consisting in the measurement of the dependence of the apparent decay time on the correlator sampling time. The polydispersity index can be determined by comparing these dependences with the theoretical ones obtained using correlation curves simulated for various values of the polydispersity index, assuming lognormal and Schulz-Zimm distributions of molecular weights. The test measurements on polystyrene standards having molecular weights in the range 9 103 – 20.6 106 give polydispersity index values Mw/Mn that are in a good agreement with those given by the manufacturer. The polydispersity index for polystyrene having the molecular weight Mw = 20.6 106 thus determined was Mw/Mn = 1.35.
The polarographic and voltammetric determination of N,N-dimethyl-4-amino-3'-methylazobenzene
Authors: Barek Jiří , Pastor Tibor J. , Votavová Simona , Zima Jiří
Published: June 2010

The polarographic reduction of N,N-dimethyl-4-amino-3'-methylazobenzene has been studied, a mechanism has been proposed and conditions have been found for the determination of this depolarizer using TAST polarography and differential pulse polarography at a classical dropping mercury electrode and using fast scan differential pulse voltammetry and linear scan voltammetry at a hanging mercury drop electrode. The detection limit at this electrode is about 10-8 mol l-1; a further decrease can be attained using adsorption accumulation of the determined azo-substance on the surface of the working electrode. In conclusion, the practical usefulness of these methods combined with extraction or thin-layer chromatography was verified.
Liquid circulation in a cylindrical baffled vessel of high height/diameter ratio with two impellers on the same shaft
Authors: Fořt Ivan , Machoň Václav , Hájek Jiří , Fialová Eva
Published: June 2010

The paper deals with the experimental study of the indicating particle circulation in a liquid mechanically agitated with two high-speed impellers (two standard turbine impellers or a lower standard turbine and upper six inclined (at 45°) plane blade impeller) on the same shaft in a slender vessel (its height equals double of the vessel diameter) equipped with four radial baffles at its walls under the turbulent flow regime of agitated charge. The visual method of observation of the indicating particle is used to investigate the model system. Four types of the particle circulation are examined: its circulation in the lower part of the system (pumping effect of the lower impeller), its circulation in the upper part of the system (pumping effect of the upper impeller), and the exchangeable circulation between the upper and lower part of the system and vice versa. It follows from the obtained average data of the above-mentioned circulations that the homogeneous circulation of charge in the whole system is reached providing the vertical distance of the high-speed impellers is equal to at least double of their diameter, their pumping capacities being approximately double compared to those reached in the system with one impeller where the off-bottom liquid level height is equal to the vessel diameter. It follows from the comparison of two arrangements, when the upper high-speed impeller pumps liquid either upwards or downwards, that the homogeneous circulation of all the charge agitated is attained in the first of both the cases compared.
Friedel-Crafts chloroethylation of hexamethylbenzene
Authors: Mindl Jaromír , Sebastiani Giovanni Vittorio
Published: June 2010

The reaction of hexamethylbenzene I with 1,2-dichloroethane in the presence of aluminium chloride gives 1-(2-chloroethyl)-1,2,3,4,5,6-hexamethylbenzenium salt (II) which is decomposed with water. The decomposition products include hexamethylbenzene (I), 3-(2-chloroethyl)-1,2,3,4,5-pentamethyl-6-methylene-1,4-cyclohexadiene (IIIa), 5-(2-chloroethyl)-1,2,3,4,5-pentamethyl-6-methylene-1,3-cyclohexadiene (IIIb), and 1-(2-chloroethyl)-2,3,4,5,6-pentamethylbenzene (IV). The compounds IIIa and IIIb are rearranged into 1-(3-chloropropyl)-2,3,4,5,6-pentamethylbenzene (V).
Determinants of β-lactam resistance in meningitis-causingEnterobacteriaceaein Brazil
Authors: Andrade L. N. , Minarini L. A.R. , Pitondo-Silva A. , Clímaco E. C. , Palazzo I. C.V. , Medeiros M. I.C. , Darini A. L.C.
Published: June 2010

This study analyzed resistance determinants in extended-spectrum β-lactamase (ESBL)-producing enterobacteria and the epidemiology of 11 Escherichia coli isolates obtained from meningitis patients in a region of Brazil from 2000 to 2005. ESBL-encoding genes and their genetic environment were investigated by PCR and sequencing. The gene blaCTX-M-2was identified in 3 different enterobacteria (E. coli, Serratia marcescens , and Proteus mirabilis ) downstream of the insertion sequence ISCR1 (localized in class 1 integrons), but not as part of the resistance cassettes region. Multilocus sequence typing (MLST) was used to investigate genetic relationships between the 11 E. coli isolates in this study and strains associated with meningitis in the E. coli MLST database. MLST analysis indicated high genetic diversity among isolates, and no significant genetic relationship was identified with meningitis-causing E. coli in the database. The results in this report reinforce the need to be attentive to meningitis suspected to be due to ESBL-producing enterobacterial isolates, especially where ESBL epidemiology is well known.
Determination of methanogenic Archaea abundance in a mesophilic biogas plant based on 16S rRNA gene sequence analysis
Authors: Bergmann I. , Nettmann E. , Mundt K. , Klocke M.
Published: June 2010

Energy production of renewable raw material is of increasing importance for sustainable energy production. As an indispensable prerequirement for further upgrading of technical equipment and operation modes of biogas plants, a deeper knowledge of the microbial community responsible for methane formation is crucial. To overcome these limitations a mesophilic biogas plant converting pig manure, maize silage, and grains of crop was sampled and subsequently analysed by construction of a methanogenic Archaea specific 16S rRNA gene clone library combined with PCR–RFLP analysis and group-specific quantitative real-time PCR (qPCR). Seventy percent of all analysed clones belonged to the order Methanomicrobiales, whereas 13% belonged to Methanosarcinales, 6% belonged to the Methanobacteriales group, and 11% of all detected clones were assigned to the CA11 and Arch1 cluster. Comparable percentages were obtained with qPCR: 84% of all detected 16S rRNA gene copy numbers were affiliated with the Methanomicrobiales, while only 14% belonged to the Methanosarcinales and 2% to the Methanobacteriales order. In conclusion, both approaches detected similar archaeal groups and revealed nearly the same abundance, pointing to a predominance of hydrogenotrophic methanogens in the biogas plant.
ANALYSIS OF GLUCOSE REGULATION USING FUZZY CLUSTERING BASED PIECEWISE AFFINE APPROXIMATION APPROACH
Authors: GHOSH S. , MAKA S.
Published: June 2010

This paper deals with the analysis of the nonlinear glucose regulation system from its Piecewise Affine (PWA) equivalent Piecewise Affine (PWA) equivalent model. The use of PWA model was motivated by the fact that it has developed as an attractive tool for nonlinear system analysis in recent years, since it allows the use of well developed concepts in the field of linear systems and control theory. The analysis mainly involves the behavioral study of the system at steady state for different types of input and different sets of physiological parameters. The number of affine systems required to represent a nonlinear system is an important consideration in PWA modeling. In this paper, the optimal number of piecewise affine systems is obtained by a technique based on a fuzzy clustering. From the PWA representation, it is possible to determine the equilibrium point (basal condition) of the glucose regulation system quite easily without solving a complex transcendental equation. The presence of a compensating mechanism between insulin sensitivity and insulin secretion is utilized by the PWA model to determine a particular profile (characteristics) for insulin sensitivity for a modified insulin secretion characteristics that would maintain a normal basal glucose level. A condition for the existence of a stable limit cycle of plasma glucose concentration as a function of delay in hepatic glucose production is determined from the model. This allowed determining the point of hopf bifurcation without carrying out extensive simulations, as is done with the existing models. The response obtained from the numerical simulation of the model, is in line with the experimental results.
MODELING THE BASIC ARRIVAL STRUCTURE OF A 400 Hz ACOUSTIC PULSE THROUGH THE SOUTH CHINA SEA BASIN
Authors: BERNOTAVICIUS CHRISTOPHER S. , CHIU CHING-SANG , MILLER CHRISTOPHER W. , REEDER D. BENJAMIN , WEI RUEY-CHANG , YANG YING-JANG , CHIU LINUS
Published: June 2010

As part of the Windy Island Soliton Experiment (WISE), a sound source and a receiver were moored on two deep-water moorings, 167-km apart, in the northeastern South China Sea basin. The source transmitted phase-modulated acoustic signals with a carrier frequency of 400 Hz for approximately one year. The receptions thus captured the multi-scale variability in the signal transmissions induced by the ocean mesoscale variability and the progression of the transbasin ocean internal tides and waves. A numerical two-dimensional acoustic propagation model based on Hamiltonian ray tracing is utilized to replicate the observed basic arrival structure and transmission loss. Being able to accurately model the basic arrival structure is a necessary first step before modeling the observed variability can be attempted. The comparison of the modeled arrival structure with the actual data is utilized to refine the angular resolution of the ray fan in the model, to estimate the geo-acoustic properties of the bottom, and to develop transmission loss estimates. Transmission loss measurements obtained from several sonobuoys deployed along the transmission path are used as an independent metric to evaluate the model.
EFFECTS OF RANDOMLY DISTRIBUTED INFILL ON COLUMNS OF REINFORCED CONCRETE FRAMES WITH SOFT GROUND STOREY
Authors: QUAYYUM SHAHRIAR , NAZMUL ISLAM MOHAMMAD , IASMIN MOST. MAHBUBA , AMANAT KHAN MAHMUD
Published: June 2010

Reinforced concrete (RC) frames with an open ground floor and various infill distributions have been analyzed for seismic loadings by the finite element method. The infills have been modeled by diagonal struts. Focus is placed on the effects of infill distribution on various structural responses, including (i) the lateral deflection, (ii) the column axial forces, (iii) the column bending moments, (iv) the base shear, and (v) the natural period of the frame. The equivalent static force method (ESFM) and response spectrum method (RSM) for linear structures have been applied, and the results obtained have been compared. It was found that the structural responses do not change appreciably by the ESFM analysis for random infill distributions, while they increase noticeably in the RSM analysis. This manifests the inadequacy of using the ESFM for general purposes, for which modifications were proposed in this paper for the design of RC columns. As the natural period of the RC frame converges with the code equations only for higher amounts of infill, it is necessary to incorporate the amount and distribution of infill in the dynamic analysis of RC frames.