554 research outputs found
Dba-free" Palladium Intermediates Of The Heck-matsuda Reaction."
The dba-free Heck-Matsuda reaction was investigated via direct ESI-MS(/MS) monitoring. Palladium species involved in the reduction of Pd(II) during a Wacker type reaction and several dba-free arylpalladium transient complexes were detected and characterized. Based on these findings, a more comprehensible catalytic cycle for this pivotal reaction is suggested.113277-8
Atmospheric Pressure Thermal Dissociation of Phospho- and Sulfopeptides
Several phospho- and sulfopeptides were subjected to atmospheric pressure thermal dissociation (APTD), which was effected by passing peptide ions generated by electrosonic spray ionization (ESSI) through a heated coiled metal tube. Sequence informative fragment ions including a-, b-, c-, and y-types of ions were observed with increased relative intensities under APTD compared with collision-induced dissociation (CID), performed inside the ion trap. A certain degree of preservation of phosphate and sulfate ester moieties was observed for some fragments ions under APTD. The neutral fragments generated outside the mass spectrometer were further analyzed via on-line corona discharge to provide rich and complementary sequence information to that provided by the fragment ions directly obtained from APTD, although complete losses of the modification groups were noted. Improved primary sequence information for phospho- and sulfopeptides was typically obtained by analyzing both ionic and neutral fragments from APTD compared with fragment ions from CID alone. Localization of the modification sites of phospho- and sulfopeptides was achieved by combining the structural information acquired from APTD and CID
Developmental Phases of Individual Mouse Preimplantation Embryos Characterized by Lipid Signatures using Desorption Electrospray Ionization Mass Spectrometry
Distribution and sources of aliphatic and polycyclic aromatic hydrocarbons in surface sediments of Itajaí-Açu estuarine system in Brazil
The Itajaí-Açu estuarine system, located in southern Brazil, has great economic importance due to the presence of two ports (Itajaí and Navegantes). This system is affected by industrial and dredging activities, which can cause the remobilization of pollutants accumulated over time in the sediment. In this context, hydrocarbons were assessed in twelve surface sediment samples. n-Alkane and polycyclic aromatic hydrocarbons (PAH) concentrations were determined by gas chromatography and their sources assessed. Total concentrations ranged between 0.50 ± 0.04 and 69.70 ± 3.90 μg g-1 dry weight (d.w.) for n-alkanes and from 63.9 ± 12.1 to 1459.0 ± 43.5 ng g-1 d.w. for PAH. Most of the sediment samples presented carbon preference index (CPI) values close to unity, indicating that the area is submitted to petroleum-related sources, mainly close to Itajaí harbor, where an intense unresolved complex mixture (UCM) was observed. The presence at all stations of αβ-hopane biomarkers also indicated petrogenic input. Based on selected PAH ratios, the sedimentary PAH composition reflects a mixture of both petrogenic and pyrolytic sources. A comparison of the PAH concentrations found in this study with those listed in the sediment quality guidelines (SQGs) indicated that adverse biological effects on the biota are rarely expected.The Itajaí-Açu estuarine system, located in southern Brazil, has great economic importance due to the presence of two ports (Itajaí and Navegantes). This system is affected by industrial and dredging activities, which can cause the remobilization of pollu28460361
Lower Extremity Salvage in the Setting of Bullous Pemphigoid Exacerbation: A Case Report
Bullous pemphigoid is an autoimmune blistering disease where patients suffer from painful bullae, often covering large portions of the skin and requiring management with immune-suppression. Our case report of recurring bullous pemphigoid illustrates the importance of considering immunosuppressive perioperative management in patients with a history of autoimmune blistering even when the disease has been quiescent for some time. With multidisciplinary care and immune suppressive therapies in the perioperative period, a free flap complicated by recurrent bullous pemphigoid can be salvaged
Fingerprinting of propolis by easy ambient sonic-spray ionization mass spectrometry
Chemical profiles of a representative set of 49 propolis ethanolic extracts collected worldwide (North and South America, Europe, Asia and Oceania) were obtained via easy ambient sonic-spray ionization mass spectrometry (EASI-MS). This simple and easily implemented fingerprinting technique analyses directly (without any pre-separation or sample manipulation) a tiny droplet of the ethanolic extract placed on a inert surface under ambient conditions. Data acquisition took about a minute per sample with no substantial sample carry-over. Extraction of propolis with ethanol by using an ultrasonic bath method gave EASI-MS data similar to the traditional maceration method, reducing total analysis time for the crude propolis resin from a week to just ca 1 h. Principal component analysis of the EASI-MS data is shown to group samples according to the plant sources of their resins, which characterizes their geographical origin. © 2009 Elsevier B.V. All rights reserved
Interactive hyperspectral approach for exploring and interpreting DESI-MS images of cancerous and normal tissue sections
Metabolização do herbicida sulfentrazona: obtenção e identificação de 3-idroximetilsulfentrazona em urina de mamíferos.
Os agrotóxicos são freqüentemente aplicados no decorrer dos ciclos das culturas para controlar organismos deletérios ou para impedir o crescimento de plantas daninhas. Muitos deles representam uma ameaça toxicológica progressiva para a vida animal e humana (ANG et al., 2005). Entre os herbicidas utilizados nas principais culturas do estado de São Paulo está o sulfentrazona que pode ser aplicado pósplantio ou como pré-emergente em relação às plantas daninhas (FAIRBANKS, 2005). É classificado na categoria toxicológica III, portanto perigoso ao meio ambiente, mas não é carcinogênico. Segundo divulgação do Instituto Brasileiro de Geografia e Estatística, em 2004 o uso de agrotóxicos no Brasil aumentou 22%, passando de 2.3 kg ha-1 para 2.8 kg ha-1 (FELICONIO, 2006). Os herbicidas representam 49% dentro desse total e seu uso está concentrado nas culturas de soja, cana-de-açúcar, milho, arroz e algodão (PACHIONE, 2004). O herbicida sulfentrazona N-[2,4?dicloro-5-[4- (difluorometil)-4,5-dihidro-3-metil-5-oxo-1H-1,2,4-triazol- 1-yl]-fenil] etanossulfonamida, inibe a enzima protoporfirinogênio oxidase (Protox) (DAYAN, et al., 1998). As características deste produto que influem no seu comportamento ambiental são: moderadamente solúvel, não susceptível a hidrólise, extremamente susceptível a fotólise direta em água, muito estável para a fotólise em solo, meia-vida de 1,5 anos sob condições aeróbias, meiavida de nove anos em condições anaeróbias, alta mobilidade em solo, média do coeficiente de partição, Koc= 43, e do coeficiente de sorção, Kd2855 mg.kg-1), este composto foi isolado de urina de rato após a administração do composto parental. Devido à dificuldade de obtenção do metabólito, para uso como padrão em análise de resíduos, e altíssimo custo de síntese, foi objetivo deste trabalho isolá-lo em urina de ratos Wistar, tratados com o agrotóxico, para fins de estudos de degradação do composto parental, pois já está bem estabelecido na literatura que mamíferos, como ratos, são capazes de metabolizar o herbicida
Coupling of Vinylic Tellurides with Alkynes Catalyzed by Palladium Dichloride: Evaluation of Synthetic and Mechanistic Details
Assessment of adulteration of cosmetics based on vegetable oils by GC-FID and lipid profile using direct infusion electrospray ionization mass spectrometry (ESI-MS)
CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPPR - FUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO PARANÁVegetable oils have properties that are beneficial to the human skin, and so, they are being used increasingly as ingredients of many cosmetic preparations; however, they are targets of adulteration. This study will evaluate the authenticity of Brazilian291224572465CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPPR - FUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO PARANÁCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPPR - FUNDAÇÃO ARAUCÁRIA DE APOIO AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO PARANÁsem informaçãosem informaçãosem informaçã
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