bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deletion of BMP7 affects the development of bones, teeth, and other ectodermal appendages of the orofacial complex
Authors: Zouvelou Vasiliki , Luder Hans‐Ulrich , Mitsiadis Thimios A. , Graf Daniel 
Published: May 2009

AbstractSequential and reciprocal epithelial–mesenchymal interactions govern the development of most tissues and organs of the craniofacial region. Bone morphogenetic proteins (BMPs) are members of the transforming growth factor‐β family of secreted signaling molecules that have long been implied to have a significant contribution in this process. However, evidence for such a role during craniofacial development is largely missing. Using a lacZ reporter mouse we mapped the spatiotemporal expression of BMP7 in the developing craniofacial region. The observed pattern suggested a potential involvement of BMP7 in epithelial–mesenchymal interactions and thus a direct role for this molecule in the development of ectodermal appendages (teeth, hair follicle, lachrymal and sweat glands, taste buds) and, furthermore, palatal formation. To correlate the expression to function we analyzed germline deleted conditional BMP7‐deficient embryos for malformations. We found developmental defects in many craniofacial structures such as teeth, eyes, whiskers, hair follicles, salivary glands, and palate. These findings place BMP7 as a central mediator of epithelial–mesenchymal interactions that are necessary for the correct development of structures belonging to the orofacial complex. J. Exp. Zool. (Mol. Dev. Evol.) 312B:361–374, 2009. © 2009 Wiley‐Liss, Inc.
Synthesis and antitumor activity of novel pyrazolylenaminone and bis(pyrazolyl)ketones via hydrazonoyl halides
Authors: Shawali Ahmad S. , Sherif Sherif M. , El‐Merzabani Mahmoud M. , Darwish Manal A. A. 
Published: May 2009

Abstract
magnified image3‐Acetyl‐4‐benzoyl‐1,5‐diphenylpyrazole reacts with DMF‐DMA to give the novel enaminone 2. The reaction of the latter with various hydrazonoyl halides afforded regioselectively the respective substituted (3‐pyrazolyl)(4‐pyrazolyl)ketones 4 in good over all yield. The preliminary screening for the antitumor activity of the synthesized compounds 2 and 4a, 4b, 4c, 4d, 4e, 4f, 4g against human breast cancer cell line (MCF‐7) revealed that both compounds 2 and 4b have high‐antitumor activity. SAR is discussed. J. Heterocyclic Chem., 46, 548 (2009).
Synthesis and reactivity of spiro[1,3,4‐thiadiazoline‐2,4′‐thioflavans] and analogues
Authors: Somogyi László 
Published: May 2009

Abstract
magnified imageRacemic thioflavanone (thio)acylhydrazones undergo transformation into racemic 3‐acetylspiro[1,3,4‐oxa(thia)‐diazoline‐2,4′‐thioflavans] with trans O(1) or S(1) and Ph(2′eq) under acetylating conditions. Conjugation between the ethylenic bond and sp2 C(4) in thioflavones encumber both the formation of (thio)acylhydrazones and their subsequent spirocyclization. On the other hand, subsequent dehydrogenation of the thiopyran moiety of spiro compounds results in formation of sp2 C(4) and simultaneous degradation of the spirodiazoline ring. J. Heterocyclic Chem., 46, 399 (2009).
Reaction of 4,5‐dichloro‐2‐chloromethylpyridazin‐3(2H)‐one with phenols
Authors: Kang Seung‐Beom , Park Song‐Eun , Lee Hyung‐Geun , Kim Bo Ram , Jung Kwang‐Ju , Won Ju‐Eun , Kim Min‐Jung , Yoon Yong‐Jin 
Published: May 2009

Abstract
magnified imageThe regiochemistry was investigated for the reaction of 2‐chloromethyl‐4,5‐dichloropyridazin‐3(2H)‐one (1) with some phenols 2 in the presence of a base in organic solvents. Seven diphenoxy derivatives 5 were synthesized selectively from 1 and phenols 2 under two optimized conditions. The product distributions of these reactions are dependent on the base, the solvent, and/or the substitutes of phenols. J. Heterocyclic Chem., (2009).
Multiecho time‐resolved acquisition (META): A high spatiotemporal resolution dixon imaging sequence for dynamic contrast‐enhanced MRI
Authors: Saranathan Manojkumar , Rettmann Dan , Bayram Ersin , Lee Christine , Glockner James 
Published: May 2009

AbstractPurposeTo evaluate a new dynamic contrast‐enhanced (DCE) imaging technique called multiecho time‐resolved acquisition (META) for abdominal/pelvic imaging. META combines an elliptical centric time‐resolved three‐dimensional (3D) spoiled gradient‐recalled echo (SPGR) imaging scheme with a Dixon‐based fat‐water separation algorithm to generate high spatiotemporal resolution volumes.Materials and MethodsTwenty‐three patients referred for hepatic metastases or renal masses were imaged using the new META sequence and a conventional fat‐suppressed 3D SPGR sequence on a 3T scanner. In 12 patients, equilibrium‐phase 3D SPGR images acquired immediately after META were used for comparing the degree and homogeneity of fat suppression, artifacts, and overall image quality. In the remaining 11 of 23 patients, DCE 3D SPGR images acquired in a previous or subsequent examination were used for comparing the efficiency of arterial phase capture in addition to the qualitative analysis for the degree and homogeneity of fat suppression, artifacts, and overall image quality.ResultsMETA images were determined to be significantly better than conventional 3D SPGR images for degree and uniformity of fat suppression and ability to visualize the arterial phase. There were no significant differences in artifact levels or overall image quality.ConclusionMETA is a promising high spatiotemporal resolution imaging sequence for capturing the fast dynamics of hyperenhancing hepatic lesions and provides robust fat suppression even at 3T. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.
Study of the characteristic fragmentation behavior of hydroquinone glycosides by electrospray ionization tandem mass spectrometry with optimization of collision energy
Authors: Liu Ying , He Jiuming , Zhang Ruiping , Shi Jiangong , Abliz Zeper 
Published: May 2009

AbstractThe fragmentation behavior of hydroquinone glycosides involving one or two sugar groups fromFraxinus sieboldianaand their analogue arbutin was investigated systematically by electrospray ionization tandem mass spectrometry in negative ion mode. The characteristic fragmentation reaction of these compounds was through the homolytic and heterolytic cleavage of theO‐glycosidic bond to produce radical aglycone ion ([Y0− H]−•) and aglycone ion (Y0−), respectively. Unambiguous differentiation between the mono‐O‐glycoside isomers which differ in glycosylation position was achieved by comparing the relative abundance of [Y0− H]−•and Y0−ions with the optimized collision energy. In the fragmentation of 1, 4‐di‐O‐glycosides, only the Y0−ion was produced when the first glucosyl residue was expelled. However, both the [Y0− H]−•and Y0−ions were present when the second glucosyl residue was eliminated. In addition, an interesting [Y0‐2H]−ion was present in the product ion spectra of hydroquinone glycosides with methoxy group(s) substituted at C‐3 or/and C‐5 positions of the benzene ring. The results of this study can facilitate the rapid determination of hydroquinone glycosides in crude plant extracts and also reveal that the systematic investigation and optimization of collision energy play an important role in the differentiation of isomers which have subtle differences in structures. Copyright © 2009 John Wiley & Sons, Ltd.
Snow in the McMurdo Dry Valleys, Antarctica
Authors: Fountain Andrew G. , Nylen Thomas H. , Monaghan Andrew , Basagic Hassan J. , Bromwich David 
Published: May 2009

AbstractSnowfall was measured at 11 sites in the McMurdo Dry Valleys to determine its magnitude, its temporal changes, and spatial patterns. Annual values ranged from 3 to 50 mm water equivalent with the highest values nearest the coast and decreasing inland. A particularly strong spatial gradient exists in Taylor Valley, probably resulting from local uplift conditions at the coastal margin and valley topography that limits migration inland. More snow occurs in winter near the coast, whereas inland no seasonal pattern is discernable. This may be due, again, to local uplift conditions, which are common in winter. We find no influence of the distance to the sea ice edge. Katabatic winds play an important role in transporting snow to the valley bottoms and essentially double the precipitation. That much of the snow accumulation sublimates prior to making a hydrologic contribution underscores the notion that the McMurdo Dry Valleys are indeed an extreme polar desert. Copyright © 2009 Royal Meteorological Society
Differential response of short‐ and long‐duration cassava cultivars to applied mineral nitrogen
Authors: Byju G. , Haripriya Anand M. 
Published: May 2009

AbstractThe differential response of two contrasting cassava cultivars to different rates of soil‐applied nitrogen (N) on the number of tuberous roots, harvest index, yield, nitrogen uptake, and fertilizer‐nitrogen‐use efficiency was studied over a period of 2 years on a typic Plinthustults in Kerala state in Southern India. The experiment was laid out in a split‐plot design with two popular cultivars of cassava, namely Sree Vijaya (6 months) and M‐4 (10 months) in the main plots, and eight urea‐N rates (0, 12.5, 25, 50, 75, 100, 150, and 200 kg ha–1) in subplots. Half of the N was applied at the time of planting and the other half 60 d later. The study revealed significant differences between the two cultivars regarding their response to fertilizer‐N application. The tuberous‐root yield of the short‐duration cultivar Sree Vijaya increased significantly up to 100 kg N ha–1 whereas the yield of the long‐duration cultivar M‐4 increased significantly only up to 50 kg N ha–1 rate. Also the N‐use‐efficiency parameters (i.e., agronomic, recovery, and physiological efficiencies) were higher in Sree Vijaya than in M‐4 but declined at N rates beyond 100 kg ha–1. The more efficient N use in the short‐duration cultivar was associated with a higher N uptake and a more efficient internal use.
Comparison of extraction techniques and modeling of accelerated solvent extraction for the authentication of natural vanilla flavors
Authors: Cicchetti Esmeralda , Chaintreau Alain 
Published: May 2009

AbstractAccelerated solvent extraction (ASE) of vanilla beans has been optimized using ethanol as a solvent. A theoretical model is proposed to account for this multistep extraction. This allows the determination, for the first time, of the total amount of analytes initially present in the beans and thus the calculation of recoveries using ASE or any other extraction technique. As a result, ASE and Soxhlet extractions have been determined to be efficient methods, whereas recoveries are modest for maceration techniques and depend on the solvent used. Because industrial extracts are obtained by many different procedures, including maceration in various solvents, authenticating vanilla extracts using quantitative ratios between the amounts of vanilla flavor constituents appears to be unreliable. When authentication techniques based on isotopic ratios are used, ASE is a valid sample preparation technique because it does not induce isotopic fractionation.
Potential of combining of liquid membranes and molecularly imprinted polymers in extraction of 17β‐estradiol from aqueous samples
Authors: Nemulenzi Olga , Mhaka Byron , Cukrowska Ewa , Ramström Olof , Tutu Hlanganani , Chimuka Luke 
Published: May 2009

AbstractThe potential of combination of liquid membranes (microporous membrane liquid–liquid extraction) and molecularly imprinted polymers (MIPs) was performed using 17β‐estradiol (E2) as model compound. The model compound was extracted from aqueous sample through a hydrophobic porous membrane that was impregnated with hexane/ethyl acetate (3:2), which also formed part of the acceptor phase. In the acceptor phase, the compound was bound onto MIP particles that were also part of the organic phase. The potential of such combination was optimised for the type and amount of MIP particles in the organic acceptor phase, the extraction time, and the type of organic acceptor solvent. Ultrasound assisted binding of E2 onto MIP particles was also investigated. MIPs prepared by precipitation polymerization were found to be superior to those prepared by bulk polymerization. Increase in the extraction time and the amount of MIP particles in the acceptor phase led to more E2 binding onto the MIP particles. Hexane/ethyl acetate (3:2) as an organic acceptor was found to give higher E2 binding onto MIP particles compared to toluene, diethyl ether, and hexane. Ultrasound was furthermore found to increase the binding of E2 onto MIP particles. The selectivity of the technique was demonstrated by extracting wastewater and where clean chromatograms were obtained compared to liquid membrane extractions (SLMs) alone.
Development and validation of an LC method for the determination of emtricitabine and related compounds in the drug substance
Authors: Ashenafi Dunge , Verbeek Ann , Hoogmartens Jos , Adams Erwin 
Published: May 2009

AbstractA robust, precise, sensitive, linear, and simple RP LC method coupled with UV for the determination of emtricitabine or 2′,3′‐dideoxy‐5‐fluoro‐3′‐thiacytidine (FTC) and its related substances is described. The method uses an RP C18 column (25 cm×4.6 mm i.d.), 5 μm kept at a temperature of 35°C. The mobile phases for gradient elution consist of ACN, phosphate buffer (pH 4.4), and water. The flow rate is 1.0 mL/min and UV detection is performed at 280 nm. A system suitability test (SST) was developed to verify the adequate performance of the chromatographic system. The developed method was further validated with respect to robustness, precision, sensitivity, and linearity. A central composite design was applied to examine the robustness of the method. The method shows good precision, sensitivity, linearity, and robustness. Three commercial FTC samples were examined using this method. This method is suitable to be used for the determination of related substances and assay of FTC.
Quantitative structure migration relationship modeling of migration factor for some benzene derivatives in micellar electrokinetic chromatography
Authors: Fatemi Mohammad Hossein , Shamseddin Hoda , Malekzadeh Hanieh 
Published: May 2009

AbstractMultiple linear regression (MLR) and artificial neural network (ANN) were used to predict the migration factors of benzene derivatives in MEKC. Some topological and electronic descriptors were calculated for each solute in the data set, and then the stepwise MLR method was used to select more significant descriptors and MLR model development. The selected descriptors are: Kier & Hall index (order1), relative negative charge surface area, HA dependent HDSA‐2/TMSA, C component of moment of inertia, Y component of dipole moment and SDS to decanol ratio in mobile phase. In the next step these descriptors were used as input of an ANN. After optimization and training of ANN it was used to predict the migration factors of external test set as well as internal and training sets. The root mean square errors for ANN predicted migration factors of training, internal and external test set were 0.110, 0.231 and 0.228, respectively, while these values are 0.200, 0.240 and 0.247 for the MLR model, respectively. Comparison between these values and other statistical parameters for these two models revealed that there were not any significant differences between ANN and MLR in prediction of solute migration factors in MEKC.
Separation of natural product using columns packed with Fused‐Core particles
Authors: Yang Peilin , Litwinski George R. , Pursch Matthias , McCabe Terry , Kuppannan Krishna 
Published: May 2009

AbstractThree HPLC columns packed with 3 μm, sub‐2 μm, and 2.7 μm Fused‐Core (superficially porous) particles were compared in separation performance using two natural product mixtures containing 15 structurally related components. The Ascentis ExpressTM C18 column packed with Fused‐Core particles showed an 18% increase in column efficiency (theoretical plates), a 76% increase in plate number per meter, a 65% enhancement in separation speed and a 19% increase in back pressure compared to the Atlantis T3TM C18 column packed with 3 μm particles. Column lot‐to‐lot variability for critical pairs in the natural product mixture was observed with both columns, with the Atlantis T3 column exhibiting a higher degree of variability. The Ascentis Express column was also compared with the AcquityTM BEH column packed with sub‐2 μm particles. Although the peak efficiencies obtained by the Ascentis Express column were only about 74% of those obtained by the Acquity BEH column, the 50% lower back pressure and comparable separation speed allowed high‐efficiency and high‐speed separation to be performed using conventional HPLC instrumentation.
Direct UV detection of underivatized amino acids using capillary electrophoresis with online sweeping enrichment
Authors: Jiang Xuemei , Xia Zhining , Wei Weili , Gou Qian 
Published: May 2009

AbstractThis is an original report proposed a CE method for direct analysis of the underivatized amino acids using UV detection with relatively higher sensitivity, which was based on coordination interactions between amino acids and Cu (II) ions. In addition, an online sweeping preconcentration technique was easily combined to improve the detection sensitivity. Satisfying separations of the amino acids were obtained under optimized conditions: 50 mmol/L CuSO4–0.05% HAc–H2O (pH 4.5), and the separation voltage of 15 kV. The LODs for the analytes ranged from 0.1 to 0.5 μmol/L. The linearity of detection for all analytes was two orders of magnitude with the correlation coefficients greater than 0.99. The repeatability was displayed with an RSD less than 3% for migration time and peak height (n = 5). Moreover, some amino acids in real samples of human saliva and green tea were analyzed by this direct UV detection CE method with acceptable sensitivity.
Method for routine screening of pesticides and metabolites in meat based baby‐food using extraction and gas chromatography‐mass spectrometry
Authors: Przybylski Cédric , Segard Christophe 
Published: May 2009

AbstractA simple and complete multiresidue method has been developed for the routine determination of 236 pesticides and degradation products, in meat based baby‐food. This original approach combines a modified Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method using a triple partitioning extraction step with water/ACN/hexane and a system composed of GC with programmable temperature vaporization injector hyphenated to an IT‐MS. Detection was performed in full scan mode, with one quantification ion and one identification ion. We firstly report here the hexane addition in the extraction step to eliminate a major part of lipophile co‐extracts. Direct consequences were the increasing of method sensitivity and the diminishment of the frequency of maintenance of the analytical instrument. The recovery data were obtained by spiking blank samples at three concentration levels (10, 50 and 200 μg/kg) over five replicates, yielding average recoveries in the range 70–121% with a RSD evaluated between 2–15%. Linearity was fixed in the range of 10–300 μg/kg with determination coefficients (R2) superior or equal to 0.9814 for all target analytes. Best LODs and LOQs were established as 0.03 and 0.1 μg/kg, respectively. Total instrumental analysis of all molecules was carried out in less than 1 h.
Sampling and analysis of nanoparticles with cold fibre SPME device
Authors: Koziel Jacek A. , Hosseinzadeh Haddadi Shokouh , Koch Wolfgang , Pawliszyn Janusz 
Published: May 2009

AbstractA new approach is described to capture nano‐size aerosols on internally‐cooled micro tubing of the solid‐phase microextraction (SPME) device followed by convenient introduction of the collected analytes into analytical instrument. Particles were generated using an aerosol formation by homogeneous nucleation of an organic vapor, and subsequent growth to nano‐size particles by coagulation of decanedioic acid, bis[2‐ethylhexyl] ester (DEHS). The approach was validated by using carbon dioxide‐cooled micro tubing to collect the nanosize DEHS particles followed by analyses on GC‐flame ionization detector (FID). Particle size ranged from 150 to 590 nm. Temperature difference between the SPME device and DEHS particles mixture created a temperature gradient and resulted in thermophoretic effect that was determining the extraction rate. SPME device was cooled to as low as –75°C, while the DEHS remained close to room temperature. Several aspects of nanoparticle sampling were tested to demonstrate the principle of the sampling approach. These included the effects of thermal gradient, sample flow rate, sampling time, CO2 delivery mode (constant coolant delivery vs. constant temperature), and particle size. Results were normalized to measure particulate concentrations using direct sampling with PTFE filters. Nanoparticle extractions of DEHS mass were proportional to sampling time. Normalized mass of DEHS extracted increased with increase in temperature gradient and with increase of the cross flow velocity. Preliminary results indicate that the variation of heat transfer boundary layer caused by the variation in the cross flow velocity produce self‐compensating effect at constant coolant delivery, indicating that this approach could be used for field determinations including the time‐weighted average sampling of nanoparticles. Thus, it may be possible to develop simple device based on this concept for field applications.
Characterization of volatile substances in apples from Rosaceae family by headspace solid‐phase microextraction followed by GC‐qMS
Authors: Ferreira Liseth , Perestrelo Rosa , Caldeira Michael , Câmara José S. 
Published: May 2009

AbstractThe volatile composition of different apple varieties of Malus domestica Borkh. species from different geographic regions at Madeira Islands, namely Ponta do Pargo (PP), Porto Santo (PS), and Santo da Serra (SS) was established by headspace solid‐phase microextraction (HS‐SPME) procedure followed by GC‐MS (GC‐qMS) analysis. Significant parameters affecting sorption process such as fiber coating, extraction temperature, extraction time, sample amount, dilution factor, ionic strength, and desorption time, were optimized and discussed. The SPME fiber coated with 50/30 μm divinylbenzene/carboxen/PDMS (DVB/CAR/PDMS) afforded highest extraction efficiency of volatile compounds, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 50°C for 30 min with constant magnetic stirring. A qualitative and semi‐quantitative analysis between the investigated apple species has been established. It was possible to identify about 100 of volatile compounds among pulp (46, 45, and 39), peel (64, 60, and 64), and entire fruit (65, 43, and 50) in PP, PS, and SS apples, respectively. Ethyl esters, terpenes, and higher alcohols were found to be the most representative volatiles. α‐Farnesene, hexan‐1‐ol and hexyl 2‐methylbutyrate were the compounds found in the volatile profile of studied apples with the largest GC area, representing, on average, 24.71, 14.06, and 10.80% of the total volatile fraction from PP, PS, and SS apples. In PP entire apple, the most abundant compounds identified were α‐farnesene (30.49%), the unknown compound m/z (69, 101, 157) (21.82%) and hexyl acetate (6.57%). Regarding PS entire apple the major compounds were α‐farnesene (16.87%), estragole (15.43%), hexan‐1‐ol (10.94), and E‐2‐hexenal (10.67). α‐Farnesene (30.3%), hexan‐1‐ol (18.90%), 2‐methylbutanoic acid (4.7%), and pentan‐1‐ol (4.6%) were also found as SS entire apple volatiles present in a higher relative content. Principal component analysis (PCA) of the results clustered the apples into three groups according to geographic origin. Linear discriminant analysis (LDA) was performed in order to detect the volatile compounds able to differentiate the three kinds of apples investigated. The most important contributions to the differentiation of the PP, PS, and SS apples were ethyl hexanoate, hexyl 2‐methylbutyrate, E,E‐2,4‐heptadienal, p‐ethyl styrene, and E‐2‐hexenal.