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Meso
Terms modified by Meso Selected AbstractsValidation of model for end-stage liver disease score to serum sodium ratio index as a prognostic predictor in patients with cirrhosisJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 9 2009Xiao-Hui Lv Abstract Aim:, To evaluate the prognostic ability of model for end-stage liver disease (MELD) to serum sodium (SNa) ratio (MESO) index and to compare the predictive accuracy of the MESO index with the MELD score and the modified Child,Turcotte,Pugh (CTP) score for short-term survival in cirrhotic patients. Methods:, A total of 256 patients with cirrhosis were retrospectively evaluated. The predictive accuracy of the MESO index, MELD score and modified CTP score were compared by the area under the receiver,operator characteristic curve (AUC). Results:, Using 1-month and 3-month mortality as the end-point, overall, MESO and MELD were significantly better than the CTP score in predicting the risk of mortality at 1 month (AUC, 0.866,0.819 vs 0.722, P < 0.01) and 3 months (AUC, 0.875,0.820 vs 0.721, P < 0.01). In the low MELD group, the AUC of MESO index (0.758, 0.759) and CTP score (0.754, 0.732) were higher than that of the MELD score (0.608, 0.611) at 1 month and 3 months, respectively (P < 0.01). However, in the high MELD group, the AUC of MESO index (0.762, 0.779) and MELD (0.737, 0.773) were higher than that of the CTP score (0.710, 0.752) at 1 month and 3 months, respectively, although there were no significant differences (P > 0.05). With appropriate cut-offs for the MESO index, the mortality rate of patients in high MESO was higher (57.1% at 1 month and 69.2% at 3 months) than that of the low MESO (5.5% at 1 month and 7.9% at 3 months) (P < 0.01). Conclusions:, The MESO index, which adds SNa to MELD, is a useful prognostic marker and is found to be superior to the MELD score and modified CTP score for short-term prognostication of patients with cirrhosis. [source] Model for end-stage liver disease score to serum sodium ratio index as a prognostic predictor and its correlation with portal pressure in patients with liver cirrhosisLIVER INTERNATIONAL, Issue 4 2007Teh-Ia Huo Abstract Background: The models for end-stage liver disease (MELD) and serum sodium (SNa) are important prognostic markers in cirrhosis. A novel index, MELD to SNa ratio (MESO), was developed to amplify the opposing effect of MELD and SNa on outcome prediction. Methods: A total of 213 cirrhotic patients undergoing hepatic venous pressure gradient (HVPG) measurement were retrospectively analyzed. Results: The MESO index correlated with HVPG (r=0.258, P<0.001) and Child,Pugh score (,=0.749, P<0.001). Using mortality as the end point, the area under receiver operating characteristic curve (AUC) was 0.860 for SNa, 0.795 for the MESO index and 0.789 for MELD (P values all >0.3) at 3 months. Among patients with Child,Pugh class A or B, the MESO index had a significantly higher AUC compared with MELD (0.80 vs. 0.766, P<0.001). A MESO index <1.6 identified 97% of patients who survived at 3 months and the predicted survival rate was 96.5%. In survival analysis, MESO index >1.6 independently predicted a higher mortality rate (relative risk: 3.32, P<0001) using the Cox model. Conclusions: The MESO index, which takes into account the predictive power of both MELD and SNa, is a useful prognostic predictor for both short- and long-term survival in cirrhotic patients. [source] From Micro to Meso: an exercise in determining hydraulic conductivity of fractured sandstone cores from detailed characterization of the fracturesGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2006Salima Baraka-Lokmane SUMMARY Hydraulic conductivities of fractured sandstone bore cores of 0.1 m in diameter are calculated using detailed characterization of the fracture geometry parameters determined using a resin casting technique. The accuracy of the measurements was about 0.25,1.25 ,m with the image size used. The values of the effective fracture apertures vary between 10 ,m and 50 ,m. For modelling purposes the samples are sectioned serially, perpendicular to the flow direction along the cylinder axis. The hydraulic conductivity of individual slices is estimated by summing the contribution of the matrix (assumed uniform) and each fracture (depending on its length and aperture). Finally, the hydraulic conductivity of the bulk sample is estimated by a harmonic average in series along the flow path. Results of this geometrical upscaling compare favourably with actual conductivity measured in hydraulic and pneumatic experiments carried out prior to sectioning. This study shows that the determination of larger-scale conductivity can be achieved, based on the evaluation of fracture geometry parameters (e.g. fracture aperture, fracture width and fracture length), measured using an optical method, at least at the laboratory scale. [source] A comparative analysis of restoration measures and their effects on hydromorphology and benthic invertebrates in 26 central and southern European riversJOURNAL OF APPLIED ECOLOGY, Issue 3 2010Sonja C. Jähnig Summary 1.,Hydromorphological river restoration usually leads to habitat diversification, but the effects on benthic invertebrates, which are frequently used to assess river ecological status, are minor. We compared the effects of river restoration on morphology and benthic invertebrates by investigating 26 pairs of non-restored and restored sections of rivers in Austria, Czech Republic, Germany, Italy and the Netherlands. 2.,Sites were grouped according to (1) region: central Europe vs. southern Europe; (2) river type: mountain vs. lowland rivers; (3) restoration approach: active vs. passive restoration and (4) a combination of these parameters. All sites were sampled according to the same field protocol comprising hydromorphological surveys of river and floodplain mesohabitats, microhabitats at the river bottom and habitat-specific sampling of benthic invertebrates. Restoration effects were compared using Shannon,Wiener Indices (SWIs) of mesohabitats, microhabitats and invertebrate communities. Differences in metric values between non-restored and restored sites were compared for 16 metrics that evaluated hydromorphology and the benthic invertebrate community. 3.,Mean SWIs differed for both mesohabitats (1·1 non-restored, 1·7 restored) and microhabitats (1·0 non-restored, 1·3 restored), while SWIs for invertebrate communities were not significantly different (2·4 non-restored, 2·3 restored). Meso- and microhabitat metrics in the restored sections were usually higher compared with the non-restored sections, but the effects on invertebrate metrics were negligible. 4.,Measures in southern Europe and mountainous regions yielded larger differences between non-restored and restored sections of rivers. Differences in the meso- and microhabitat metrics were largest for actively restored sections of central European mountain rivers and rivers from southern Europe, followed by passively restored mountain rivers in central Europe. The smallest differences were observed for lowland sites. There was no significant restoration effect on invertebrate metrics in any categories. 5.,Synthesis and applications. Restoration measures addressing relatively short river sections (several hundred metres) are successful in terms of improving habitat diversity of the river and its floodplain. Active restoration measures are suitable if short-term changes in hydromorphology are desired. To realize changes in benthic invertebrate community composition, habitat restoration within a small stretch is generally not sufficient. We conclude that restoring habitat on a larger scale, using more comprehensive measures and tackling catchment-wide problems (e.g. water quality, source populations) are required for a recovery of the invertebrate community. [source] A comparative U,Th,Pb (zircon,monazite) and 40Ar,39Ar (muscovite,biotite) study of shear zones in northern Victoria Land (Antarctica): implications for geochronology and localized reworking of the Ross OrogenJOURNAL OF METAMORPHIC GEOLOGY, Issue 6 2007G. DI VINCENZO Abstract Mylonitic granites from two shear zones in northern Victoria Land (Antarctica) were investigated in order to examine the behaviour of the U,Th,Pb system in zircon and monazite and of the 40Ar,39Ar system in micas during ductile deformation. Meso- and micro-structural data indicate that shear zones gently dip to the NE and SW, have an opposite sense of shear (top-to-the-SW and -NE, respectively) and developed under upper greenschist facies conditions. In situ U,Pb dating by laser-ablation inductively coupled plasma-mass spectrometry of zircon areas with well-preserved igneous zoning patterns (c. 490 Ma) confirm that granites were emplaced during the Early Cambrian to Early Ordovician Ross,Delamerian Orogeny. Monazite from the Bier Point Shear Zone (BPSZ) mainly yielded U,Th,Pb ages of c. 440 Ma, in agreement with in-situ Ar laserprobe ages of syn-shear muscovite and with most Ar ages of coexisting biotite. The agreement of ages derived from different decay schemes and from minerals with different crystal-chemical features suggests that isotope transport in the studied sample was mainly controlled by (re)crystallization processes and that the main episode of ductile deformation in the BPSZ occurred at c. 440 Ma. Cathodoluminscence imaging showed that zircon from the BPSZ contains decomposed areas with faint relics of oscillatory zoning. These areas yielded a U,Pb age pattern which mimics that of monazite but is slightly shifted towards older ages, supporting previous studies which suggest that ,ghost' structures may be affected by inheritance. In contrast, secondary structures in zircon from the Mt. Emison Shear Zone (MESZ) predominantly consist of overgrowths or totally recrystallized areas and gave U,Pb ages of c. 450 and 410 Ma. The c. 450-Ma date matches within errors most monazite U,Th,Pb ages and in-situ Ar ages on biotite aligned along the mylonitic foliation. This again suggests that isotope ages from the different minerals are (re)crystallization ages and constrains the time of shearing in the MESZ to the Late Ordovician. Regionally, results indicate that shear zones were active in the Late Ordovician,Early Silurian and that their development was partially synchronous at c. 440 Ma, suggesting that they belong to a shear-zone system formed in response to ,NE,SW-directed shortening. Taking into account the former juxtaposition of northern Victoria Land and SE Australia, we propose that shear zones represent reactivated zones formed in response to stress applied along the new plate margin as a consequence of contractional tectonics associated with the early stages (Benambran Orogeny) of the development of the Late Ordovician,Late Devonian Lachlan Fold Belt. [source] Soil-plant relationships, micronutrient contents, and cardenolide production in natural populations of Digitalis obscuraJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2004Luis Roca-Pérez Abstract The production of secondary metabolites by plants growing in natural populations is conditioned by environmental factors. In the present study, we have investigated the relationships among soil properties, micronutrients in soils and plants, and cardenolide production from wild Digitalis obscura (Scrophulariaceae) populations. Young and mature leaves and soil samples were collected in ten different populations, corresponding to three Mediterranean bioclimatic belts (Thermo-, Meso-, and Supramediterranean belts). Soil (total and EDTA-extractable) and leaf micronutrients (Fe, Mn, Zn, and Cu), and leaf cardenolide accumulation have been determined. Significant negative correlations were observed between Fe, Mn or Zn concentration in leaves and soil pH, as well as between Fe or Mn in leaves and carbonate content of soils. Only EDTA-extractable Mn was significantly correlated with Mn content in the plants. With regard to cardenolide content in leaves, this parameter was negatively correlated with Znleaf in young leaves and with Mnleaf in old leaves. Positively correlated, however, were Fe and cardenolide content in young leaves. The influence of environmental conditions and leaf micronutrient contents on cardenolide accumulation is discussed. Boden-Pflanze-Wechselwirkungen im Hinblick auf Mikroelement- und Cardenolidgehalte in wilden Digitalisobscura -Populationen Die Produktion von sekundären Stoffwechselprodukten in Pflanzen ist in hohem Grad abhängig von Umweltfaktoren. In dieser Studie wurde bei Wildtypen von Digitalis obscura der Einfluss bodenchemischer Eigenschaften (pH, Karbonatgehalt, Gesamt- und EDTA-extrahierbare Mikronährstoffgehalte) auf die Mikronährstoff- (Fe, Mn, Zn und Cu) und Cardenolidgehalte in den Pflanzen untersucht. Verwendet wurden Proben von jungen und reifen Blättern sowie Bodenproben aus zehn verschiedenen Populationen in drei bioklimatischen Zonen (Thermo-, Meso- und Supramittelmeergebiet). Festgestellt wurden signifikant negative Beziehungen zwischen Fe-, Mn- oder Zn-Gehalten in den Blättern und dem pH des Bodens, sowie zwischen Fe- oder Mn-Konzentration in den Blättern und dem Karbonatgehalt der Böden. Nur EDTA-extrahierbares Mn wies eine positive Beziehung zu den Mn-Gehalten in den Pflanzen auf. Die Ergebnisse deuten darauf hin, dass die Gehalte von Mikroelementen in den Blättern von D. obscura stärker vom pH des Bodens abhängig sind als von den Gesamt- oder den extrahierbaren Mikroelementgehalten der Böden. Ebenso wurden signifikant negative Beziehungen zwischen Cardenolidgehalten und Zn-Gehalten in jungen Blättern, sowie Mn-Gehalten in älteren Blättern festgestellt. Die Fe-Gehalte in jungen Blättern waren jedoch positiv mit dem Cardenolidgehalt korreliert. Diese Befunde werden im Hinblick auf die Cardenolidbiosynthese diskutiert. [source] Production of l -2,3-butanediol by a new pathway constructed in Escherichia coliLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2004S. Ui Abstract Aims:, A metabolic pathway for l -2,3-butanediol (BD) as the main product has not yet been found. To rectify this situation, we attempted to produce l -BD from diacetyl (DA) by producing simultaneous expression of diacetyl reductase (DAR) and l -2,3-butanediol dehydrogenase (BDH) using transgenic bacteria, Escherichia coli JM109/pBUD-comb. Methods and Results:, The meso -BDH of Klebsiella pneumoniae was used for its DAR activity to convert DA to l -acetoin (AC) and the l -BDH of Brevibacterium saccharolyticum was used to reduce l -AC to l -BD. The respective gene coding each enzyme was connected in tandem to the MCS of pFLAG-CTC (pBUD-comb). The divided addition of DA as a source, addition of 2% glucose, and the combination of static and shaking culture was effective for the production. Conclusions:,l -BD (2200 mg l,1) was generated from 3000 mg l,1 added of DA, which corresponded to a 73% conversion rate. Meso -BD as a by-product was mixed by 2% at most. Significance and Impact of the Study:, An enzyme system for converting DA to l -BD was constructed with a view to using DA-producing bacteria in the future. [source] Crystallization and preliminary X-ray studies of meso -2,3-butanediol dehydrogenase from Klebsiella pneumoniae IAM1063ACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2001Masato Otagiri Meso -2,3-butanediol dehydrogenase (meso -BDH) has been crystallized and preliminary X-ray crystallographic characterization of meso -BDH crystals has been performed. Single crystals of meso -BDH were prepared in two forms by the hanging-drop vapour-diffusion method using polyethylene glycol as a precipitant. Form I crystals belong to space group C2, with unit-cell parameters a = 215.5, b = 79.4, c = 134.8,Å, , = 98.22°, and form II crystals belong to space group P21, with unit-cell parameters a = 69.16, b = 109.78, c = 127.28,Å, , = 102.29°. The crystals diffracted to 2.0 and 1.7,Å resolutions, respectively, using synchrotron radiation. [source] Temporal-Spatial Structure of Intraplate Uplift in the Qinghai-Tibet PlateauACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2010Dewei LI Abstract: The intraplate uplift of the Qinghai-Tibet Plateau took place on the basis of breakup and assembly of the Precambrian supercontinent, and southward ocean-continent transition of the Proto-, Paleo-, Meso- and Neo-Tethys during the Caledonian, Indosinian, Yanshanian and Early Himalayan movements. The intraplate tectonic evolution of the Qinghai-Tibet Plateau underwent the early stage of intraplate orogeny characterized by migrational tectonic uplift, horizontal movement and geological processes during 180,7 Ma, and the late stage of isostatic mountain building characterized by pulsative rapid uplift, vertical movement and geographical processes since 3.6 Ma. The spatial-temporal evolution of the intraplate orogeny within the Qinghai-Tibet Plateau shows a regular transition from the northern part through the central part to the southern part during 180,120 Ma, 65,35 Ma, and 25,7 Ma respectively, with extensive intraplate faulting, folding, block movement, magmatism and metallogenesis. Simultaneous intraplate orogeny and basin formation resulted from crustal rheological stratification and basin-orogen coupling that was induced by lateral viscous flow in the lower crust. This continental dynamic process was controlled by lateral flow of hot and soft materials within the lower crust because of slab dehydration and melted mantle upwelling above the subducted plates during the southward Tethyan ocean-continent transition processes or asthenosphere diapirism. Intraplate orogeny and basin formation were irrelevant to plate collision. The Qinghai-Tibet Plateau as a whole was actually formed by the isostatic mountain building processes since 3.6 Ma that were characterized by crust-scale vertical movement, and integral rapid uplift of the plateau, accompanied by isostatic subsidence of peripheral basins and depressions, and great changes in topography and environment. A series of pulsative mountain building events, associated with gravity equilibrium and isostatic adjustment of crustal materials, at 3.6 Ma, 2.5 Ma, 1.8,1.2 Ma, 0.9,0.8 Ma and 0.15,0.12 Ma led to the formation of a composite orogenic belt by unifying the originally relatively independent Himalayas, Gangdisê, Tanghla, Longmenshan, Kunlun, Altyn Tagh, and Qilian mountains, and the formation of the complete Qinghai-Tibet Plateau with a unified mountain root after Miocene uplift of the plateau as a whole. [source] Reclassification of the Meso- and Neoproterozoic Chronostratigraphy of North China by SHRIMP Zircon AgesACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 6 2009GAO Linzhi Abstract: High-quality zircon U-Pb ages acquired from Meso- and Neoproterozoic strata in North China in recent years has provided a high-resolution chronostratigraphic framework for dating. A basis of this high-level chronostratigraphic system provides the foundation for a global Precambrian study and stratigraphic correlation and so recent geological studies have focused attention on systemic SHRIMP zircon dating. A chronology of Meso- and Neoproterozoic strata and the time of origin of the overlying Changcheng System is given on the basis of new SHRIMP zircon dating from the Qianxi Complex and diabase of the Chuanlinggou Formation. A new tectonostratigraphy for a Neoproterozoic chronostratigraphic framework in the southeastern margin of the North China continent is underpinned by the new SHRIMP zircon dating of a Neoproterozoic mafic magma diabase in the Jiao-Liao-Xu-Huai Sub-Province. [source] Analyse des grenzschichtnahen Stofftransports an frei aufsteigenden GasblasenCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 10 2009D. Kück Dipl.-Ing. Abstract In Gas-/Flüssigkeits-Kontaktapparaten hat die möglichst effektive Ausnutzung der Gasphase bei minimalen Energiekosten, optimalen Kontaktzeiten und hohen Stoffaustauschraten eine maßgebende Bedeutung. Dabei werden Nachlaufgebiete von dispergierten Gasblasen zunehmend auch als lokale Mischorgane verstanden, die einen wesentlichen Beitrag zur Meso- und Mikrovermischung in Mehrphasenströmungen leisten. Ein besseres Verständnis der Vorgänge im grenzschichtnahen Bereich eröffnet neue Perspektiven zur Prozessintensivierung und damit zur gezielten Reaktionsführung. Zur umfassenden Beschreibung des gekoppelten Impuls-, Wärme- und Stoffaustausches in Mehrphasenströmungen sind jedoch Detailkenntnisse erforderlich, die bisher aufgrund der komplexen Zusammenhänge und messtechnischen Unzugänglichkeit nur in geringem Maße zur Verfügung stehen. Ergebnisse von Untersuchungen der sich grenzschichtnah ausbildenden Geschwindigkeits- und Konzentrationsfelder an frei aufsteigenden Gasblasen in wässriger Umgebung werden beschrieben. Hierbei werden die sich einstellenden Geschwindigkeits- und Konzentrationsfelder mittels Particle Image Velocimetry (PIV) und Laser Induzierter Fluoreszenz (LIF) vermessen, um lokale hydrodynamische Effekte sowie örtliche Konzentrationsgradienten entlang der Phasengrenzfläche aufzuklären. Hierdurch wird eine Massenstrombilanzierung und Berechnung lokaler, momentaner Stoffaustauschraten ermöglicht. Während im ersten Teil dieser Arbeit die Mess- und Auswertungsmethodik erläutert wird, erfolgt im zweiten Teil die Darstellung und Diskussion der Ergebnisse. [source] Colonisation of pitcher plant leaves at several spatial scalesECOLOGICAL ENTOMOLOGY, Issue 4 2003M. Kurtis Trzcinski Abstract., 1.,The effect of meso-scale (zone within bog and local plant density) and fine-scale (leaf length and resource availability) factors on the colonisation of pitcher plant leaves by arthropods was examined in an eastern Canadian bog. 2.,In spring, the abundances of three arthropods, the mosquito Wyeomyia smithii, the midge Metriocnemus knabi, and the mite Sarraceniopus gibsoni, were determined for plots with low, moderate, and high densities of pitcher plants. All overwintering inhabitants were then removed from the plots. Newly opening leaves were colonised from outside the plots, and arthropod abundances were assessed again in autumn. 3.,Pitcher plant fauna varied in their response to the meso-scale factors. In autumn (soon after colonisation), midges were more abundant in areas with high densities of pitcher plants. The relationship between mosquito abundance and plant density, and the variation in abundance among zones within the bog in the spring, were probably due to overwintering mortality. 4.,All taxa responded to the fine-scale factors, leaf length, and capture rate, in the autumn, but the strength of the responses frequently depended on a meso-scale factor (plant density), in which responses were usually strongest where plants were sparse. Thus, the interaction between meso- and fine-scale processes needs to be considered when interpreting patterns of species abundance within arthropod assemblages in pitcher plant leaves. [source] Dramatic Effects of Ionic Liquid on Platinum Electrode Surface and Electron-Transfer Rates of meso -TetraphenylporphyrinsELECTROANALYSIS, Issue 12 2006Afsaneh Safavi Abstract The effect of addition of a room temperature ionic liquid, 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim][PF6], on the electrochemical behavior of different free-base para-substituted meso -tetraphenylporphyrins in dichloromethane solution has been studied using cyclic voltammetric technique. It has been found that the ionic liquid has the ability to regenerate platinum electrode surface and improves the reversibility of electrode processes. This has been true for the case of all the porphyrins studied. [source] Redox Active Two-Component Films of Palladium and Covalently Linked Zinc Porphyrin,Fullerene DyadELECTROANALYSIS, Issue 9 2006Marta Plonska Abstract Redox active films have been generated electrochemically by the reduction of dyads consisting of fullerene C60 covalently linked to zinc meso -tetraphenyloporphyrin, ZnPC60, and palladium acetate. The films are believed to consist of a polymeric network formed via covalent bonds between the palladium atoms and the fullerene moieties. In these films, the zinc porphyrin moiety is covalently linked to the polymeric chains through the pyrrolidine ring of the fullerene. The ZnPC60/Pt films are electrochemically active in both positive and negative potential excursions. At positive potentials, two oxidation steps for the zinc porphyrin are observed. In the negative potential range, electron transfer processes involving the zinc porphyrin and the fullerene entities are observed. Film formation is also accompanied by palladium deposition on the electrode surface. The presence of a metallic phase in the film influences its morphology, structure and electrochemical properties. [source] Abundance and activity of Chloroflexi -type SAR202 bacterioplankton in the meso- and bathypelagic waters of the (sub)tropical AtlanticENVIRONMENTAL MICROBIOLOGY, Issue 7 2008Marta M. Varela Summary The contribution of Chloroflexi -type SAR202 cells to total picoplankton and bacterial abundance and uptake of d - and l -aspartic acids (Asp) was determined in the different meso- and bathypelagic water masses of the (sub)tropical Atlantic (from 35°N to 5°S). Fluorescence in situ hybridization (FISH) revealed that the overall abundance of SAR202 was , 1 × 103 cells ml,1 in subsurface waters (100 m layer), increasing in the mesopelagic zone to 3 × 103 cells ml,1 and remaining fairly constant down to 4000 m depth. Overall, the percentage of total picoplankton identified as SAR202 increased from < 1% in subsurface waters to 10,20% in the bathypelagic waters. On average, members of the SAR202 cluster accounted for about 30% of the Bacteria in the bathypelagic waters, whereas in the mesopelagic and subsurface waters, SAR202 cells contributed < 5% to total bacterial abundance. The ratio of d -Asp : l -Asp uptake by the bulk picoplankton community increased from the subsurface layer (d -Asp : l -Asp uptake ratio , 0.03) to the deeper layers reaching a ratio of ,1 at 4000 m depth. Combining FISH with microautoradiography to determine the proportion of SAR202 cells taking up d -Asp versus l -Asp, we found that ,,30% of the SAR202 cells were taking up l -Asp throughout the water column while d -Asp was essentially not taken up by SAR202. This d -Asp : l -Asp uptake pattern of SAR202 cells is in contrast to that of the bulk bacterial and crenarchaeal community in the bathypelagic ocean, both sustaining a higher fraction of d -Asp-positive cells than l -Asp-positive cells. Thus, although the Chloroflexi -type SAR202 constitutes a major bathypelagic bacterial cluster, it does not contribute to the large fraction of d -Asp utilizing prokaryotic community in the meso- and bathypelagic waters of the North Atlantic, but rather utilizes preferentially l -amino acids. [source] Mesomerization of S4 -Symmetric Tetrahedral Chelate Complex [In4(L3)4]: First-Time Monitored by Temperature-Dependent 1H NMR Spectroscopy,,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2010Rolf W. Saalfrank Abstract VT 1H NMR spectroscopy proved that a non-dissociative and reversible mesomerization process links the tetranuclear indium(III) complexes meso -(,,,,,,,)(P,P,M,M)- 3 and meso -(,,,,,,,)(M,M,P,P)- 3,. During this process four tandem Bailar twists, resulting in the (,)/(,) isomerization at the indium centers, and the (P)/(M) inversion of the four coordinating face-centered, helical ligands (L3)3, are involved. In addition, gas-phase DFT calculations (B3LYP/LANL2DZp) revealed a C1 -symmetric transition state (+21.9 kcal,mol,1) for the mesomerization mechanism which connects 3 and 3,. [source] Synthesis and Characterization of Linear Tetranuclear Silver(I) Complexes Bridged by Tetraphosphane LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 32 2009Yukie Takemura Abstract Reactions of AgOTf with meso -bis[(diphenylphosphanylmethyl)phenylphosphanyl]methane (dpmppm) afforded[Ag4(OTf)2(,-OTf)(,-dpmppm)2{(CH3)2CO}](OTf) (1) and [Ag4(OTf)2(,-OTf)(,-dpmppm)2(RNC)2](OTf) {R = Xyl (2a), Mes (2b), tBu (2c)}. When AgOTf was treated with dpmppm in air in the presence of tBuNC, cleavage of the C,Cl and P,C bonds occurred to give [Ag4(,-Cl)(,-dpmppm)2(tBuNC)4](OTf)3 (3) and [Ag4(,-Ph2PO2)(,-dpmppm)2(tBuNC)3](OTf)3 (4). Reaction of AgOCOCF3 with dpmppm resulted in [Ag4(OCOCF3)2(,-OCOCF3)(,-dpmppm)2](CF3COO) (5). By treatment of AgPF6 with dpmppm, [Ag4(,-dpmppm)2(tBuNC)4](PF6)4 (6) and [Ag4(PO2F2)2(,-dpmppm)2(tBuNC)2] (PF6)2 (7) were obtained. Wheareas complexes 1,3 possess a {Ag4(,-dpmppm)2}4+ core in which the Ag4 strings are rather bent with two dpmppm ligands arranged in a syn fashion, complexes 4,7 have linear Ag4 strings supported by two dpmppm ligands arranged in an anti fashion. These results suggest that the dpmppm-supported tetrasilver(I) strings are quite flexible and labile and thus are potentially important in promoting organic reactions as a result of the multimetallic centers.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Highly Efficient Visible-Light-Induced Photocleavage of DNA by a Ruthenium-Substituted Fluorinated PorphyrinEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2009Michelle Cunningham Abstract A new porphyrin, meso -5-(pentafluorophenyl)-10,15,20-tris(4-pyridyl)porphyrin, has been synthesized. Coordination of two [Ru(bipy)2Cl]+ moieties (where bipy = 2,2,-bipyridine) to the pyridyl nitrogen atoms in the 10,15-positions gives the target complex. Electronic transitions associated with the ruthenium,porphyrin include an intense Soret band and four less intense Q-bands in the visible region of the spectrum. An intense ,,,* transition in the UV region associated with the bipyridyl groups and a metal-to-ligand charge-transfer (MLCT) band appearing as a shoulder to the Soret band are also observed. Electrochemical properties associated with the complex include a redox couple in the cathodic region with E1/2 = ,0.84 V vs. Ag/AgCl attributed to the porphyrin and a redox couple in the anodic region at E1/2 = 0.79 V vs. Ag/AgCl due to the RuIII/II couple. DNA titrations and ethidium bromide displacement experiments indicate the ruthenium porphyrin interacts with DNA potentially through a partial intercalation mechanism. Irradiation of aqueous solutions of the ruthenated complex and supercoiled DNA at a 100:1 base pair/complex ratio with visible light above 400 nm indicates that the complex causes double-strand breaks of the DNA.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Synthesis, Characterization and OFET Properties of Amphiphilic Mixed (Phthalocyaninato)(porphyrinato)europium(III) ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2009Pan Ma Abstract Amphiphilic mixed (phthalocyaninato)(porphyrinato)europium(III) triple-decker complexes Eu2[Pc(15C5)4]2[T(C10H21)4P] (1) and Eu2[Pc(15C5)4]2[TPOPP] (2) [H2Pc(15C5)4 = 2,3,9,10,16,17,23,24-tetrakis(15-crown-5)phthalocyanine; H2T(C10H21)4P = meso -5,10,15,20-tetra- n -decylporphyrin, H2TPOPP = meso -5,10,15,20-tetrakis(4-pentyloxyphenyl)porphyrin] were designed and synthesized by the raise-by-one-story method. These novel sandwich triple-decker complexes were characterized by a wide range of spectroscopic methods, and they were also electrochemically studied. Highly ordered films were fabricated by the Langmuir,Blodgett (LB) technique into organic field-effect transistors (OFETs). The devices display good OFET performance with a carrier mobility in the range 0.03,0.78 cm2,V,1,s,1. As expected, the devices show a low threshold voltage range from ,1.19 to ,4.34 V. The mobility of compound 1 reaches 0.78 cm2,V,1,s,1, which is the highest value so far achieved for LB film-based OFETs, as a result of the narrow energy gap (1.04 eV) of this compound.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Stereoselective Synthesis of the First Chatt-Type Bis(dinitrogen)-Molybdenum(0) Complex with a Tetraphosphane LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2008René Römer Abstract The first Chatt-type Mo0 dinitrogen complex with a tetraphosphane ligand has been prepared and characterized by NMR as well as infrared and Raman spectroscopy. Importantly, the employed reaction route allows the stereospecific synthesis of this complex as trans -[Mo(N2)2(meso -prP4)] (prP4 = a tetraphos ligand with a central propylene bridge). The stereoselectivity in the reaction course is induced by the oxido-iodido-molybdenum(IV) precursor [Mo(O)I(prP4)]+ which directs both phenyl groups of the bridging P atoms of prP4 into a meso configuration. The paper establishes a general strategy to synthesize mononuclear Mo0 dinitrogen and related molybdenum complexes with multidentate phosphane ligands which has not been possible to date. Moreover, the obtained molybdenum tetraphos N2 complex should exhibit a higher thermodynamic stability in the reactions of the Chatt cycle of synthetic nitrogen fixation than the conventional bis(diphos) complexes, due to the linkage of the two diphosphane units by an alkyl bridge. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Lanthanide Complexes of Disulfoxide Ligands with Varied Configurations: Influence of Lanthanide Contraction on the Structures of the ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2005Jian-Rong Li Abstract Four new disulfoxide-LnIII complexes, [Ln(L)2(NO3)3]n {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)3·nH2O with meso -1,3-bis(ethylsulfinyl)propane (meso - L) in methanol/triethylorthoformate, and their solid-state structures were characterized by IR spectroscopy, elemental analyses and X-ray diffraction. Complex 1 is a 1D double-bridged chain in which the LaIII ions are ten-coordinate and the L ligands adopt both meso and rac configurations, and a bis-monodentate bridging coordination mode. While complexes 2,4 have isostructural dinuclear structures, in which the LnIII ions are nine-coordinate and the ligands show two types of coordination fashions and configurations: bis-monodentate bridging with a meso -configuration, and monodentate coordination with a rac -configuration. The structural differences between 1 and 2,4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthesis and Physicochemical Characterization of Bis(macrocycles) Involving a Porphyrin and a meso -Substituted Corrole , X-ray Crystal Structure of a [(Free-base porphyrin),corrole]bis(pyridine)cobalt ComplexEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2005Jean-Michel Barbe Abstract A very efficient, simple synthesis of face-to-face porphyrin,corrole free-bases bearing substituents at the meso positions of the corrole ring is reported. Starting from the (porphyrin,aldehyde)zinc species 1Zn, porphyrin,corrole free-bases (3M, 3C) are obtained in two steps, in fairly good yields (40,43,%), compared to 11 steps for their corrole ,-pyrrole-substituted counterparts. Moreover, the possibility to directly synthesize the free-base (porphyrin,corrole)cobalt complex (5M or 5C) allows for the further preparation of heterodimetallic derivatives. Crystals of the bis(pyridine) adduct of 5M have been grown; the molecular structure clearly shows that the two pyridine molecules are coordinated to the cobalt ion in endo and exo positions, leading to an open-mouth geometry of the bis(macrocycle). The structure of 5M(py)2also shows intermolecular ,,, interactions along the [1,0,0] direction, leading to stacking of the complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthesis and Characterization of Mixed Phthalocyaninato and meso -Tetrakis(4-chlorophenyl)porphyrinato Triple-Decker Complexes , Revealing the Origin of Their Electronic AbsorptionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2004Xuan Sun Abstract Two series of mixed phthalocyaninato and porphyrinato rare earth(III) triple-decker complexes [M2(Pc)(TClPP)2] (1a,10a) and [M2(Pc)2(TClPP)] (1b,11b) [M = Y, La,Er except Ce and Pm; Pc = phthalocyaninate; TClPP = tetrakis(4-chlorophenyl)porphyrinate] have been prepared by treating the half-sandwich complexes [M(TClPP)(acac)] (acac = acetylacetonate), generated in situ from [M(acac)3]·nH2O and H2(TClPP), with Li2(Pc). All the triple-decker complexes have been characterized by a wide range of spectroscopic and electrochemical methods. The molecular structures of [M2(Pc)(TClPP)2] (M = Y, Ho) have also been determined, and show a symmetrical disposition of ligands, with two outer domed TClPP and one inner Pc rings. A systematic investigation of the optical and electrochemical data of these complexes has revealed the nature of the HOMO and LUMO, as well as the origin of the electronic absorptions of these triple-decker complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Off the Back or on the Side: Comparison of meso and 2-Substituted Donor-Acceptor Difluoroborondipyrromethene (Bodipy) DyadsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2010Andrew C. Benniston Abstract The preparation of several difluoroborondipyrromethene (Bodipy) dyads is described incorporating covalently attached hydroquinone/quinone groups at the 2-position (BD-SHQ, BD-SQ, BD-SPHQ, BD-SPQ). The compounds, currently under investigation as chemical sensors for reactive oxygen species, show various levels of fluorescence depending on the oxidation state of the appended group. The 19F NMR spectrum for BD-SHQ in CDCl3 at room temperature reveals the two fluorines are inequivalent on the NMR timescale. In contrast, the 19F NMR spectrum for the counterpart quinone compound, BD-SQ, is consistent with two equivalent fluorine atoms. The two results are interpreted as the quinone is free to rotate around the connector bond, whereas this motion is restricted for the hydroquinone group and makes the fluorines chemically inequivalent. Cyclic voltammograms recorded for all derivatives in CH2Cl2 electrolyte solution are consistent with typical Bodipy-based redox chemistry; the potentials of which depend on factors such as presence of the phenylene spacer and oxidation state of the appended group. A comparison of the electrochemical behaviour with the counterpart meso derivatives reveals some interesting trends which are associated with the location of the HOMO/LUMOs. The absorption profiles for the compounds in CH3CN are again consistent with Bodipy-based derivatives, though there are some subtle differences in the band-shapes of the closely-coupled systems. In particular, the absorption spectra for the dyad, BD-SQ, in a wide range of solvents are appreciably broader than for BD-SHQ. Femtosecond transient absorption spectroscopy performed on the hydroquinone derivatives, BD-SHQ and its meso analogue is interpreted as electron transfer occurs from the hydroquinone unit to the first-excited singlet (S1) state of the Bodipy center, followed by ultrafast charge recombination to reinstate the ground state. The coupling of OH vibrations to the return electron transfer process is invoked to explain the lack of clear identification of the charge-separated state in the transient records. [source] Nucleophilic Substitution Reactions of meso -5,10,15-Tris(pentafluorophenyl)corrole; Synthesis of ABC-Type Corroles and Corrole-Based OrganogelsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2010Takaaki Hori Abstract Nucleophilic substitution reactions of 5,10,15-tris(pentafluorophenyl)corrole (1) with amines were examined as a post-modification route to functional corroles. Reaction of 1 with an excess of amine nucleophiles led to exclusive formation of 5,10,15-tris(4-amino-2,3,5,6-tetrafluorophenyl)-substituted corroles. In this nucleophilic reaction, 5- and 15-pentafluorophenyl substituents were found to be more reactive than the substituent at the 10-position. This substitution reaction was applied for the preparation of ABC-type corroles and corrole-based organogels. The latter exhibited a blue-shifted Soret band and small fluorescence quantum yields in nonpolar hydrocarbon solvents due to the formation of H-type aggregates. [source] Energy- and Charge-Transfer Processes in a Perylene,BODIPY,Pyridine Tripartite ArrayEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2008Mohammed A. H. Alamiry Abstract A novel boron dipyrromethene (BODIPY) dye has been synthesized in which the F atoms, usually bound to the boron center, have been replaced with 1-ethynylperylene units and a 4-pyridine residue is attached at the meso -position. The perylene units function as photon collectors over the wavelength range from 350 to 480 nm. Despite an unfavorable spectral overlap integral, rapid energy transfer takes place from the singlet-excited state of the perylene unit to the adjacent BODIPY residue, which is itself strongly fluorescent. The mean energy-transfer time is 7,±,2 ps at room temperature. The dominant mechanism for the energy-transfer process is Dexter-type electron exchange, with Förster-type dipole,dipole interactions accounting for less than 10,% of the total transfer probability. There are no indications for light-induced electron transfer in this system, although there is evidence for a nonradiative decay channel not normally seen for F -type BODIPY dyes. This new escape route is further exposed by the application of high pressure. The meso -pyridine group is a passive bystander until protons are added to the system. Then, protonation of the pyridine N atom leads to complete extinction of fluorescence from the BODIPY dye and slight recovery of fluorescence from the perylene units. Quenching of BODIPY-based fluorescence is due to charge-transfer to the pyridinium unit whereas the re-appearance of perylene-based emission is caused by a reduction in the Förster overlap integral upon protonation. Other cations, most notably zinc(II) ions, bind to the pyridine N-atom and induce similar effects but the resultant conjugate is weakly fluorescent.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Desymmetrization of meso -Bicyclic Hydrazines by Rhodium-Catalyzed Enantioselective HydroformylationEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2008Chloée Bournaud Abstract An asymmetric hydroformylation of three meso -bicyclic hydrazines followed by the reduction of the formyl product afforded the corresponding desymmetrized optically enriched hydroxymethyl hydrazines (up to 77.5,%,ee). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis of meso -Coumarin-Conjugated Porphyrins and Investigation of Their Luminescence PropertiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 26 2007Weiying Lin Abstract A series of meso -coumarin-conjugated porphyrins 1a,e were designed and synthesized. Condensation of 4-chloroacetoacetate ethyl ester with m -cresol or resorcin afforded 4-chloromethylcoumarins, which were then hydrolyzed to give coumarin alcohols, followed by oxidation to provide coumarin aldehydes. The reaction of coumarin aldehydes with pyrrole under Adler or Lindsey conditions afforded the meso -coumarin-conjugated porphyrins 1a,e. Their UV/Vis absorption spectra and photoluminescent spectra were recorded both in dilute THF solution and as solid films. Analysis of the luminescence spectra indicate that the energy transfer from the coumarin substituents to the porphyrin core for 1a,e is more efficient in solid film than in solution, and the energy transfer from the coumarin substituent to the porphyrin core for 1d and 1e is more efficient than that of 1a, 1b and 1c in solid film. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis and Reactivity of 23 - tert -Butyl- and 23 -Phenyltetraarylazuliporphyrins: an Analysis of the Effect of Bulky Substituents on Oxidative Ring Contractions to Benzocarbaporphyrins,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2007Jessica A. El-Beck Abstract 6- tert -Butyl- and 6-phenylazulene reacted with pyrrole and benzaldehyde in a molar ratio of 1:3:4 in the presence of BF3·Et2O in chloroform, followed by oxidation with DDQ, to give 23 -substituted tetraphenylazuliporphyrins in 15,20,% yield. Slightly higher yields of the related meso -tetrakis(4-chlorophenyl)azuliporphyrins were obtained using 4-chlorobenzaldehyde. The presence of an electron-donating tert -butyl substituent increased the diatropic character of the azuliporphyrin system as determined by the proton NMR chemical shifts for the internal CH resonance, while intermediary results were noted for 23 -phenylazuliporphyrins. Addition of TFA afforded dications with increased aromatic ring currents, but electron-donating substituents (tBu,>,Ph) again produced a larger upfield shift for the internal CH signal due to stabilization of the tropylium character that is required so that the system can attain carbaporphyrin-type aromaticity. The substituted azuliporphyrins reacted with nickel(II) acetate or palladium(II) acetate to give the corresponding organometallic derivatives. In addition, oxidations with tBuOOH and KOH afforded benzocarbaporphyrin products in approximately 50,% yield. The presence of tert -butyl or phenyl substituents did not block these oxidative ring contraction processes, and the rate of reaction was slightly increased compared to 23 -unsubstituted azuliporphyrins. The major products were 22 - tert -butyl or phenyl-substituted benzocarbaporphyrins and minor products with an additional formyl substituent were also isolated. These products are consistent with an initial nucleophilic addition occurring at the position adjacent to the R group on the azulene ring. Detailed mechanisms are proposed to explain these observations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis of Both Enantiomers of Conduritol C Tetraacetate and of meso -Conduritol D Tetraacetate by Oxidation of Benzoquinone Bis(ethylene acetal)EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2007Martin Lang Abstract Epoxidation of p -benzoquinone bis(ethylene acetal) (1) with m -chloroperbenzoic acid or hydrogen peroxide/benzonitrile afforded corresponding monoepoxide 2, which was converted into p -benzoquinone mono(ethylene acetal) monoepoxide 5 with perchloric acid. Dihydroxylation of 1 with osmium tetroxide or ruthenium trichloride/sodium periodate afforded corresponding cis -diol 6, which was subsequently acetylated to give diacetate 7. One ethyleneacetal moiety in 7 could be selectively hydrolyzed with silica gel/ferric chloride under solvent-free conditions to give ketone 8, which, upon reduction with sodium borohydride and subsequent acetylation of the formed alcohol group, afforded two diastereomeric triacetates 10. Hydrolysis of the remaining acetal functions in the two diastereomers 10, followed by reduction of the second carbonyl group as described above, afforded racemic conduritol C and meso -conduritol D tetraacetates 12 and 13, respectively. Enzymatic resolution of the racemic arabino -configured triacetate 10 with Lipozym failed, while the ribo -configured counterpart reacted smoothly to give enantiomerically pure D - ribo - and L - ribo -configured triacetates 10. The latter pair of enantiomerically pure triacetates were converted into both enantiomers of conduritol C tetraacetate 13 as described for the racemic compounds. (© Wiley-VCH Verlag GmbH & Co. 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