			Home About us Contact

Variety Of Reactions (variety + of_reaction)

Distribution by Scientific Domains

Medical Sciences	50%
Chemistry	50%

Selected Abstracts

3,5-Bis(n -perfluorooctyl)benzyltriethylammonium Bromide (F-TEBA): An Efficient, Easily Recoverable Fluorous Catalyst for Solid-Liquid PTC Reactions

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009
Gianluca Pozzi
Abstract A readily available 3,5-bis(perfluorooctyl)benzyl bromide and triethylamine were reacted under mild conditions to give 3,5-bis(n -perfluorooctyl)benzyltriethylammonium bromide (F-TEBA), an analogue of the versatile phase-transfer catalyst, benzyltriethylammonium chloride (TEBA), containing two fluorous ponytails. This perfluoroalkylated quaternary ammonium salt was successfully employed as a catalyst in a variety of reactions run under solid-liquid phase-transfer catalysis (SL-PTC) conditions. Thus, being both hydrophobic and lipophobic, F-TEBA could be quickly recovered in quantitative yields, and reused without loss of activity over several reaction cycles. [source]

The antioxidant capacity of saliva

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 3 2002
M. Battino
Abstract Background/aims: Saliva, a heterogeneous fluid comprising proteins, glycoproteins, electrolytes, small organic molecules and compounds transported from the blood, constantly bathes the teeth and oral mucosa. It acts as a cleansing solution, an ion reservoir, a lubricant and a buffer. In addition to its other host-protective properties, saliva could constitute a first line of defence against free radical-mediated oxidative stress, since the process of mastication and digestion of ingested foods promotes a variety of reactions, including lipid peroxidation. Moreover, during gingival inflammation, gingival crevicular fluid flow increases the change of saliva composition with products from the inflammatory response; this, in turn, could have some rôle in controlling and/or modulating oxidative damages in the oral cavity. This is the reason why the antioxidant capacity of saliva has led to increasing interest, and the development of techniques suitable for saliva antioxidant evaluation. Materials and Methods: Here, we review the current peer-reviewed literature concerning the nature and characteristics of free radicals, reactive oxygen species, oxidants, pro-oxidants and antioxidants in saliva, especially pro-oxidant and antioxidant features, as well as current methods for assessing the antioxidant capacity of saliva. Results and Conclusions: In the last decade, several methods have been developed for assaying the antioxidant activity of saliva, indicating an increasing interest of researchers and clinicians. Unfortunately, systematic studies of saliva are still lacking, even in healthy populations. Zusammenfassung Hintergrund/Zielsetzung: Der Speichel, eine heterogene Flüssigkeit bestehend aus Proteinen, Glykoproteinen, Elektrolyten, kleinen organischen Molekülen und Bestandteilen aus dem Blut, umspült andauernd Zähne und Mundschleimhäute. Er wirkt als Reinigungslösung, Reservoir für Ionen, als Schmiermittel und als Puffer. Zusätzlich zu seinen anderen Abwehreigenschaften könnte der Speichel eine erste Verteidigungslinie gegen durch freie Radikal verursachten oxidativen Stress sein, da der Prozess der Nahrungszerkleinerung und -verdauung eine Vielzahl von Reaktionen auslöst einschließlich der Lipidperoxidation. Darüber hinaus erhöht sich während gingivaler Entzündung der Sulkusflüssigkeitsfluss und verändert die Zusammensetzung des Speichels durch Produkte der Entzündungsreaktion. Dies könnte eine Rolle bei der Kontrolle und/oder Beeinflussung oxidativer Schäden in der Mundhöhle spielen. Dies sind die Gründe dafür, warum die antioxidative Kapazität des Speichels zu einem wachsenden Interesse und zur Entwicklung von Techniken geführt hat, die die Bestimmung der antioxidativen Kapazität des Speichels erlauben. Material und Methoden: In diesem Übersichtsartikel wird die akutelle Literatur hinsichtlich der Natur und Charakteristika freier Radikale, reaktiver Sauerstoffarten, Oxidantien, Prooxidantien und Antioxidantien im Speichel, insbesondere Eigenschaften der Pro- und Antioxidantien sowie aktuelle Methoden zur Bestimmung der antioxidative Kapazität des Speichels, dargestellt. Ergebnisse/Schlussfolgerungen: Während des vergangenen Jahrzehnts wurden mehrere Methoden für die Bestimmung der antioxidativen Kapazität des Speichels entwickelt, was für ein wachsendes wissenschaftliches und klinisches Interesse spricht. Unglücklicherweise fehlen noch systematische Studien zum Speichel selbst für gesunde Kollektive. Résumé Origine/but: La salive, fluide hétérogène constitué de protéines, de glycoprotéines, d'électrolytes, de petites molécules organiques et de composés transportés du sang, baigne constamment les dents et les muqueuses buccales. Elle agit comme une solution nettoyante, comme réservoir d'ions, comme lubrifiant et comme tampon. En plus de ces propriétés protectrices pour l'hôte, la salive pourrait constituer une première ligne de défense contre le stress oxydatif dû aux radicaux libres puisque le processus de mastication et de digestion des nourritures ingérées induit une variété de réactions, telle la peroxidation des lipides. De plus, pendant l'inflammation gingivale, le flux gingival sulculaire augmente et altère la compositon de la salive par les produits de la réponse inflammatoire. Cela, à son tour, pourrait avoir un rôle dans le contrôle ou la modulation des dommages oxydatifs dans la cavité buccale. C'est la raison pour laquelle la capacité antioxydant de la salive a connu un intérêt croissant et le développement de techniques fiables pour l'évaluation des antioxydants salivaires. Matériaux et méthodes: Ici, nous passons en revue de façon concise la littérature actuelle concernant la nature et les caractéristiques des radicaux libres, des espèces réactives à l'oxygène, des oxydants, des pro-oxydants et des antioxydants dans la salive, particulièrement les caractéristiques pro-oxydante et antioxydante et les méthodes actuelles de mise en évidence des capacités antioxydantes de la salive. Résultats et conclusions: Lors de la dernière décade, plusieurs méthodes ont été développées pour tester l'activité antioxydante de la salive, ce qui prouve un intérêt grandissant des chercheurs et des cliniciens. Malheureusement, des études systématiques sur la salive manquent même pour les populations saines. [source]

Do Suicide Survivors Suffer Social Stigma: A Review of the Literature

PERSPECTIVES IN PSYCHIATRIC CARE, Issue 1 2005
Jacqueline G. Cvinar
One of the delineating elements found in suicide bereavement versus normal bereavement is the stigma experienced by survivors. This review of the literature will provide insight into stigma as an underlying element in suicide bereavement and point to the role of health professionals in dealing with this complex issue. Historical review and empirical studies are analyzed to provide a framework for how suicide relates to natural bereavement. The conclusion is that suicide bereavement is different from natural loss. The challenge to health care providers is to sort through the complex issues surrounding the individual and their social network to find mechanisms that lead to resolution. Suicide has a profound effect on the family, friends, and associates of the victim that transcends the immediate loss. As those close to the victim suffer through bereavement, a variety of reactions and coping mechanisms are engaged as each individual sorts through individual reactions to the difficult loss. Bereavement refers to "all the physiological, psychological, behavioral, and social response patterns displayed by an individual following the loss (usually through death) of a significant person or thing" (Dunne, Dunne-Maxim & McIntosh, 1987). Bereavement following suicide is complicated by the complex psychological impact of the act on those close to the victim. It is further complicated by the societal perception that the act of suicide is a failure by the victim and the family to deal with some emotional issue and ultimately society affixes blame for the loss on the survivors. This individual or societal stigma introduces a unique stress on the bereavement process that in some cases requires clinical intervention. [source]

Purification, crystallization and preliminary X-ray analysis of cytochrome P450 219A1 from Novosphingobium aromaticivorans DSM 12444

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009
Chuan Hong
Cytochrome P450 enzymes catalyze a variety of reactions and are widely distributed in living organisms. In recent studies, the first members of five new families of cytochrome P450 enzymes have been identified, including cytochrome P450 219A1 (CYP219A1) from Novosphingobium aromaticivorans DSM 12444. It has also been reported that isolongifolen-9-one (C15H22O), a sesquiterpenoid ketone derivative, is a potential substrate for CYP219A1, inducing a ,95% shift of the haem spin state to high spin upon binding. The CYP219A1 protein has been crystallized and single crystals have been studied by X-ray crystallography. Diffraction data were collected to 2.4,Å resolution. The crystals belonged to space group P6, with unit-cell parameters a = 93.1, b = 93.1, c = 98.0,Å. Preliminary X-ray diffraction data analysis revealed that the asymmetric unit contained one protein molecule. [source]