bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Thiolato-Bridged Trinuclear Heterometal Complexes with 2-[(3-Aminopropyl)amino]ethanethiol
Authors: Mikuriya Masahiro , Tsutsumi Hideyuki , Nukada Ryoji , Handa Makoto , Sayama Yasuyoshi 
Published: June 2006

Abstract
A series of ten trinuclear heterometal complexes with 2-[(3-aminopropyl)amino]ethanethiol (HL), [(MAL2)2MB](ClO4)2·2dmac·2X ([MA, MB] = [Mn, Zn], [Mn, Cd], [Fe, Zn], [Fe, Cd], [Fe, Hg], [Co, Zn] [Co, Cd], [Ni, Zn], [Ni, Cd], [Ni, Hg]; dmac = N,N-dimethylacetamide, X = H2O or CH3OH), have been synthesized and characterized by infrared and electronic spectroscopies, temperature dependence of magnetic susceptibilities (80—300 K), and single-crystal X-ray diffraction technique. Each complex has a thiolato-bridged heterotrinuclear structure which shows a linear arrangement of Oh(MA)–Td(MB)–Oh(MA). The spectral and magnetic properties were discussed in relation to the crystal structures.
Multielement Determination of Trace Elements in Sediment Sample by Inductively Coupled Plasma Mass Spectrometry with Microsampling Technique
Authors: Fujimori Eiji , Wei Rong , Sawatari Hideyuki , Chiba Koichi , Haraguchi Hiroki 
Published: June 2006

Abstract
A discrete microsampling technique for multielement determination of trace elements by inductively coupled plasma mass spectrometry has been investigated for analyses of samples containing large amounts of matrix elements. In the technique, 100 μl of the sample solution was introduced into the plasma by using a six-way valve, and 10 elements were detected in peak hopping mode during a single mass range scan. As a result, a transient peak profile of the signal for each element was observed at each m/z position. The peak area measurement method was established for the quantitative analysis. The optimization of instrumental conditions and matrix effects in multielement determination were investigated in detail. The discrete microsampling technique was found to reduce some memory effects due to matrices in ICP-MS. The present system was applied to the analyses of standard sediment sample and 30 elements at the μg g−1 level were successfully determined without matrix separation.
A Biomimetic Study of Cytochrome P450 Related Oxidations of Toluenes Using Synthetic Hemin
Authors: Nakano Taku , Agatsuma Noriko , Kodama Shiori , Kakuda Hiroko , Dolphin David 
Published: June 2006

Abstract
A mechanistic study of the oxidation of toluene and its derivatives in a model system designed to mimic cytochrome P450 (P450) using iron tetrakis(2,6-dichlorophenyl)porphyrin chloride (FeTPPCl8Cl) and pentafluoroiodosylbenzene (PFIB:C6F5IO) in dichloromethane is reported. The oxidation products were the corresponding benzyl alcohols and aldehydes; no further oxidation products were observed. The relative reaction rates were obtained in competitive reactions including the use of deuterated analogues. In the present model system, Hammett plots and isotope effects indicated conclusively that the rate-determining step was a hydrogen atom abstraction to the oxoiron intermediate which was then followed by a rebound of an OH group. The concerted mechanism and the rebound mechanism were discussed in terms of the differences in reactivities between the model system and natural P450 enzymes and similar monooxygenation enzymes.
Ichthyotoxic Cembranoids from the Soft Coral, Sarcophyton sp.
Authors: Iwagawa Tetsuo , Nakamura Shun , Okamura Hiroaki , Nakatani Munehiro 
Published: June 2006

Abstract
Ten new ichthyotoxic cembranoids: sartol A (1), 4-O-methylsartol A (2), sartones A (3), B (4), C (5), D (6), 4-O-methylsartone B (7), epoxysartone A (8), 6β-hydroxysarcotol acetate (9), and 4-O-methylsarcotol (10) have been isolated from the soft coral, Sarcophyton sp. The ichthyotoxicity tests were performed for 1, 3—7, and 10, including the reduction product and the acetate of 1.
Characterization of Collagen by Capillary Electrophoresis
Authors: Harada Osamu , Sumita Suguru , Sugita Masami , Yamamoto Tohei 
Published: June 2006

Abstract
Characterization of pepsin-solubilized type I collagen was examined by a capillary electrophoresis using a capillary coated with α-dodecyl-ω-hydroxy poly(oxyethylene) to reduce protein adsorption and electroosmic flow. A good peak separation for each polypeptide was achieved at pH 5.6—6.5. The peaks were assigned to α1, α2, β11, β12, and γ by gel chromatography and reversed phase HPLC. It is found that each α chain signal split into several peaks, reflecting various residues of teropeptide.
Exclusive Affinity-Labeling of μ Opioid Receptors by Morphiceptin Analogs Containing S-(3-Nitro-2-pyridylthio)cysteine
Authors: Motoyama Shihoko , Takada Kiyoshi , Yasunaga Teruo , Fujita Tsugumi , Shimohigashi Yasuyuki 
Published: June 2006

Abstract
The S-(3-nitro-2-pyridylthio) (Npys) group only reacts with a free mercapto group to form a disulfide bond. A series of morphiceptin analogs containing SNpys–cysteine were designed and synthesized for specific affinity-labeling of μ opioid receptors. Affinity-labeling of opioid receptors was monitored and evaluated by radioligand receptor binding assays using rat brain membranes and specific tritium-labeled ligands of enkephalin analogs. It was found that analogs with Cys(Npys) at position 4 or 5 bind covalently to μ receptors, but not to δ receptors, resulting in a discriminative and exclusive affinity labeling of μ opioid receptor subtype.
Transformation of Penicillins into 3-Substituted Δ3-Cephems through Addition/Cyclization of Allenecarboxylates
Authors: Tanaka Hideo , Sumida Shin-ichi , Kameyama Yutaka , Sorajo Koichi , Wada Isao , Torii Sigeru 
Published: June 2006

Abstract
A straightforward synthesis of Δ3-cephems 2 bearing heteroatom substituents directly attached to C(3)-position was performed successfully by a sequential addition/cyclization reaction of allenecarboxylate 4 derived from eithen penicillin 1. Upon treatment of the allenecarboxylate 4 with morpholine, pyrrolidine, sodium azide, and 5-methyl-1,3,4-thiadiazole-2-thiol in DMF in the presence of calcium chloride, the addition/cyclization reaction proceeded smoothly to afford the corresponding 3-substituted Δ3-cephems 2a—e. Reaction of the allenecarboxylate 4 with lithium chloride in NMP (N-methyl-2-pyrrolidone) in the presence of aluminum chloride afforded 3-chloro-Δ3-cephem 2f, while without aluminum chloride, 3-phenylsulfonyl-Δ3-cephem 2e was mainly obtained. The 3-sulfenyl-Δ3-cephems 12 were prepared by a similar addition/cyclization reaction of allenecarboxylates 10 with a catalytic amount of thiolates. The sulfenyl moieties attached at the sulfur atom of the C(4)-substituent of 10 were introduced at the C(3)-position of the cephem framework 2.
Synthesis of 2 : 1 Type 3-(Methacryloxy)propyl Magnesium (Nickel) Phyllosilicate
Authors: Fukushima Yoshiaki , Tani Masaaki 
Published: June 2006

Abstract
New organic/inorganic hybrid polymers, 2 : 1 type 3-(methacryloxy)propyl magnesium phyllosilicate and 2 : 1 type 3-(methacryloxy)propyl nickel phyllosilicate, were synthesized at room temperature by the copolymerization reaction of [3-(methacryloxy)propyl]trimethoxysilane to metal chloride hexahydrate. These polymers were studied by X-ray diffraction, Fourier-transformed infrared spectroscopy, and nuclear magnetic resonance measurements. The polymers have an inorganic part of phyllosilicate-like structure such as mica or smectite, and organic side chains linked to the inorganic framework through an –Si–C– covalent bond. The layered inorganic parts were considered consistent with well-ordered octahedral sheets and disordered –C–SiO3 tetrahedral sheets. The tendency of magnesium or nickel ions to form octahedral sheets played major part in the formation of the layered structure.
Calix[4]arene-Mediated Transport of Alkali Ions Across Synthetic Black Lipid Membranes (BLM)
Authors: Kimizuka Nobuo , Wakiyama Tatsuo , Yanagi Akihiro , Shinkai Seiji , Kunitake Toyoki 
Published: June 2006

Abstract
The calix[4]arene-mediated transport of alkali ions across black lipid membranes (BLM) of synthetic amphiphiles was examined by the charge pulse relaxation technique. Double-chain amphiphiles with cationic, anionic and nonionic head groups formed stable BLM’s, and the transport parameters for alkali ions were determined. The calix[4]arene derivative displayed an enhanced transport rate for Na+ ion across the synthetic BLM’s, while the relative adsorption/desorption rate (β) of alkali ions was significantly affected by the surface charge of the BLM’s.
Formation and release of symmetric instability following Delta‐M adjustment
Authors: Morcrette C. J. , Browning K. A. 
Published: June 2006

AbstractConditional Symmetric Instability (CSI) and Delta‐M adjustment have both been suggested as possible mechanisms to explain the slantwise circulations that lead to two‐dimensional precipitation bands near midlatitude cold fronts. Previous work has shown how the initial state required for CSI to occur is similar to the state produced as a result of Delta‐M adjustment. An idealized dry numerical model is used to test the hypothesis that slantwise circulations can occur due to the release of symmetric instability formed by the Delta‐M adjustment process. The numerical simulation shows the coexistence of two pairs of slantwise circulations: one due directly to Delta‐M adjustment, and the other which occurs in a region of symmetric instability which was formed by the Delta‐M adjustment process. The simulated circulation is qualitatively similar to some high‐resolution Doppler radar observations of vertically stacked slantwise circulations. It is argued that a combined Delta‐M/CSI mechanism may also be responsible for the creation of multiple slantwise circulations in the moist atmosphere. Copyright © 2006 Royal Meteorological Society.
On the origin of the tropical Atlantic decadal oscillation based on the analysis of the ICOADS
Authors: Lim Gyu‐ho , Suh Yong‐cheol , Kim Baek‐min 
Published: June 2006

AbstractFrom an analysis of the International Comprehensive Ocean–Atmosphere Data Set, we were able to confirm salient features of the tropical Atlantic decadal oscillation illustrated in previous works. These features include antisymmetric behaviour of surface air pressure and sea surface temperature with two centres of action residing in the tropical North and South Atlantic Oceans. In addition to the recognized features of the oscillation, we found a new aspect: the principal mechanism regulating the oscillation differs between the north and south centres of action. Decadal components of the relative humidity time series show a maximum value of lag cross‐correlation at a lag of −2 years. Such a temporal evolution was irrespective of the centres of action and the reference time series. The two reference series employed are the sunspot numbers and the southerlies over the western equatorial Atlantic. Associated with this, statistically significant phase shifts between the decadal components of variables exist, especially in the tropical North Atlantic Ocean. For the decadal oscillation, relative humidity change was dominated by specific humidity change over the tropical North Atlantic and by air temperature change over the tropical South Atlantic. For the frequency band of the solar cycle, the variation of relative humidity seemed to amplify the Earth's response to the sun's radiation changes that had previously been considered too small to affect the Earth's climate. By incorporating our new findings with the known features of the oscillation, we can suggest that the variability of solar radiation may be crucial as an originator, or at least as a regulator, of the oscillation in combination with the climate distribution of clouds and water vapour over the tropical Atlantic. Copyright © 2006 Royal Meteorological Society.
Synoptic and dynamic aspects of an extreme springtime Saharan dust outbreak
Authors: Knippertz Peter , Fink Andreas H. 
Published: June 2006

AbstractIn March 2004, a large‐scale, strong and persistent outbreak of Saharan dust on to the adjacent tropical and subtropical Atlantic Ocean was observed in satellite imagery. Surface observations show that the event was accompanied by unusual weather conditions across large parts of North Africa including low temperatures and strong winds over the Sahara, extreme precipitation in Libya and a heat wave on the Guinea coast. The dust outbreak was associated with an unseasonally southerly position of the Intertropical Convergence Zone and a delayed northward progression of the African monsoon.The dust front was initially related to a density current caused by strong evaporational cooling along a precipitating cloud‐band that penetrated into the northern Sahara ahead of an upper‐level trough. At later stages, massive upper‐level convergence, sinking, low‐level divergence and an explosive anticyclogenesis over northwest Africa caused strong northerly flow and a quick spreading of the dust front to the south and west. The strong pressure gradients over North Africa were further enhanced by the formation of a cyclone ahead of the upper‐trough. A dynamical analysis based on potential‐vorticity (PV) theory provides new insights into the generation of North African harmattan surges. Using a PV inversion, it is shown that the explosive anticyclogenesis was caused largely by unbalanced dynamics related to the density current, divergent outflow from the precipitation over Libya and inertial instability in the entrance region of the strong subtropical jet and tropical plume along the eastern side of the upper trough. These processes enhanced the effects of the balanced advection of negative vorticity and cold air by the large‐scale wave. Moreover, we show the importance of an explosive cyclogenesis event over the central North Atlantic for the amplification of the downstream wave associated with the penetration of the cold front into North Africa. Copyright © 2006 Royal Meteorological Society.
Adaptive data assimilation including the effect of spatial variations in observation error
Authors: Frehlich Rod 
Published: June 2006

AbstractAn optimal adaptive data assimilation algorithm is derived using the maximum likelihood method based on a conditional Gaussian probability density function for the first‐guess and direct observations of the state variables but including local estimates of the observation and first‐guess error statistics. An interpolation of the first‐guess field to the observation coordinates is not required under the assumption of locally homogeneous statistics for the random atmosphere. However, the definition of observation error requires a definition of model ‘truth’ which is defined as a spatial average of the continuous random atmospheric variables. Then the total observation error consists of two independent components: an instrument error and an observation sampling error defined by the spatial average of the observation and the statistics of the local turbulence. Estimates of the observation sampling error statistics are determined from an ensemble of background or first‐guess fields or from the analysis of the raw data from instrumented aircraft, Doppler lidars, or radar profilers. The spatial variations of the sampling error are referenced to the local turbulence conditions at each analysis coordinate and therefore each observation can have a different observation error for each nearby analysis coordinate. The extension of the adaptive assimilation concept to include the spatial variations in observation error for statistical interpolation, 3D‐Var, 4D‐Var, extended Kalman filtering, and ensemble Kalman filtering is also presented for the traditional meaning of observation error, i.e. each observation is assigned a single error. The conditional analysis error is derived for a single observation at the analysis coordinate and multiple observations around the analysis point. Example calculations of the conditional analysis error are presented for a few simple set of observation and measurement geometries to demonstrate the impact of the spatially variable observation errors. For rawinsonde observations, the observation sampling error is an important contribution to optimal adaptive data assimilation. Observations performed as a spatial average along a line, such as aircraft, radar profiler and Doppler lidar measurements, have smaller sampling errors than rawinsonde observations and therefore reduce the analysis error if the instrument error is sufficiently low. Copyright © 2006 Royal Meteorological Society.
Secondary initiation of multiple bands of cumulonimbus over southern Britain. II: Dynamics of secondary initiation
Authors: Marsham J. H. , Parker D. J. 
Published: June 2006

AbstractThe Convective Storm Initiation Project (CSIP) pilot field programme took place in the summer of 2004 in southern England. During this field campaign a case of a cold‐pool outflow initiating an arc of convection downwind of the generating storm (the ‘primary storm’) was observed. Three further arcs were initiated further downwind of this first arc. These arcs all later gave significant rainfall over south‐east England. Results from the modelling studies described in this paper show that gravity waves, generated by the ‘primary storm’, may have been responsible for initiating the further three arcs of convective showers that were observed.The modelled primary storm generates waves with a range of vertical wavelengths. These are separated by dispersion, with the higher‐order modes (with the largest vertical wavelengths) travelling fastest (approximately 30 m s−1). The fastest two modes suppressed convection and later modes increased boundary‐layer depth and so initiated convection. The multiple peaks (from non‐hydrostatic effects) in the third mode may have been responsible for the two main arcs observed and the fourth mode may have been responsible for the third arc. The amplitude of the modelled waves at low levels was much larger downwind of the primary storm than upwind and only initiated convection there, which agrees with the observations of the arcs forming downwind of the primary storm. This asymmetry appears to be caused by the moving‐wave source and asymmetric wave trapping. Finally we discuss the implications for numerical weather prediction (NWP). Reducing the resolution of the model, and varying the magnitude of the wind speed used, shows that a non‐hydrostatic high‐resolution ( ≃1 km) NWP model should be able to capture such wave processes, if the generating storm is forecast or analysed correctly. Copyright © 2006 Royal Meteorological Society.
Passive microwave radiometer channel selection basedoncloudandprecipitation information content
Authors: Michele Sabatino Di , Bauer Peter 
Published: June 2006

AbstractThe information content of microwave frequencies between 5 and 200 GHz for rain, snow and cloud water retrievals over ocean and land surfaces was evaluated using optimal estimation theory. The study was based on large datasets representative of summer and winter meteorological conditions over North America, Europe, Central Africa, South America and the Atlantic obtained from short‐range forecasts with the operational ECMWF model. The information content of rain, snow and cloud water was traded off against the uncertainties due to the natural variability of other variables that microwave observations are sensitive to. These are surface emissivity, land surface skin temperature, atmospheric temperature and moisture. The estimation of the underlying error statistics was based on ECMWF model forecast error statistics.The results suggest that a number of frequency bands are most suited for the retrieval of(i) rain over oceans: 15–18, 35–40, 80, 145, 118.75±10–14 GHz; rain over land: 85–100, 135–140 GHz,(ii) snow over land and oceans: 95–100, 140–150, 187 GHz,(iii) clouds over oceans: 40, 80–85 GHz; clouds over land: 90–100, 135–140 GHz.For radiometers designed for global and multi‐season applications, several channels in all of the above frequency ranges would be desirable for optimizing channel usage in hydrometeor retrievals depending on the observed situation. Copyright © 2006 Royal Meteorological Society.
Experimental 2D‐Var assimilation of ARM cloud and precipitation observations
Authors: Lopez Philippe , Benedetti Angela , Bauer Peter , Janisková Marta , Köhler Martin 
Published: June 2006

AbstractA two‐dimensional variational method (2D‐Var) based on 12‐hour integrations of the single‐column version of the European Centre forMedium‐RangeWeather Forecasts model for adjusting initial temperature and specifichumidity profiles is used to identify the issues related to the assimilation of either high temporal frequency or time‐accumulated observations that are directly affected by clouds and precipitation. 2D‐Var experiments have been run using cloud‐radar reflectivity profiles and microwave‐radiometer brightness temperatures in nonprecipitating cloudy cases, and accumulated rain‐gauge measurements and total column water‐vapour retrievals from the Global Positioning System in precipitating situations. All observations have been obtained from the Atmospheric Radiation Measurement Program.In cloudy situations, the use of time sequences of cloud‐radar reflectivities at half‐hourly time steps is problematic because the variational assimilation minimization becomes overconstrained. Instead, it is better to assimilate time‐averaged profiles of cloud radar reflectivities when background reflectivities are generally greater than the observations. When background reflectivities are lower than observed, the falling of the extra precipitation produced by 2D‐Var hampers the convergence of the cost‐function minimization. The assimilation of brightness temperatures seems more straightforward even at a half‐hourly frequency.As regards the application of 2D‐Var to accumulated rain‐gauge measurements, the minimization is biased towards observations that are available at the beginning of the 12‐hour assimilation window, due to the reduction of precipitation sensitivities in time. However, using three‐dimensional adjoint sensitivity computations, it is shown that this problem should not be as critical in four‐dimensional variational assimilation. It is also demonstrated that the combination of precipitation data with information about the moisture field produces more realistic 2D‐Var increments than with rain gauges solely.Finally, the implications for the future assimilation of cloud and precipitation affected observations in direct 4D‐Var are presented. Copyright © Royal Meteorological Society, 2006.