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Distribution by Scientific Domains

Life Sciences	40%

Selected Abstracts

CLINICAL STUDY: Very low dose naltrexone addition in opioid detoxification: a randomized, controlled trial

ADDICTION BIOLOGY, Issue 2 2009
Paolo Mannelli
ABSTRACT Although current treatments for opioid detoxification are not always effective, medical detoxification remains a required step before long-term interventions. The use of opioid antagonist medications to improve detoxification has produced inconsistent results. Very low dose naltrexone (VLNTX) was recently found to reduce opioid tolerance and dependence in animal and clinical studies. We decided to evaluate safety and efficacy of VLNTX adjunct to methadone in reducing withdrawal during detoxification. In a multi-center, double-blind, randomized study at community treatment programs, where most detoxifications are performed, 174 opioid-dependent subjects received NTX 0.125 mg, 0.250 mg or placebo daily for 6 days, together with methadone in tapering doses. VLNTX-treated individuals reported attenuated withdrawal symptoms [F = 7.24 (2,170); P = 0.001] and reduced craving [F = 3.73 (2,107); P = 0.03]. Treatment effects were more pronounced at discharge and were not accompanied by a significantly higher retention rate. There were no group differences in use of adjuvant medications and no treatment-related adverse events. Further studies should explore the use of VLNTX, combined with full and partial opioid agonist medications, in detoxification and long-term treatment of opioid dependence. [source]

Romarchite and associated phases as common corrosion products on pewter artifacts from marine archaeological sites

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2004
Stacie E. Dunkle
Corrosion products were examined from typical pewter artifacts originating from six different submerged archaeological sites, dating to between ca. A.D. 1550 and 1733, along the eastern seaboard of North America and in the Caribbean Sea. The artifacts were viewed as 270,450-year long experiments revealing the phases and mechanisms of tin corrosion in seawater. All of the samples analyzed exhibit abhurite (Sn3O(OH)2Cl2), romarchite (SnO), and hydroromarchite (Sn3O2(OH)2) forming at the expense of the underlying artifact. Textural analysis suggests that abhurite is the first alteration product to form at the expense of the pewter; romarchite subsequently develops and then hydroromarchite. The outermost corrosion layers on several of the most corroded artifacts also exhibit cassiterite (SnO2) as a significant and apparently final phase to form during alteration. The absence of this mineral on many samples demonstrates that, while samples appeared to be stable under the conditions that were present, cassiterite had not yet had time to form. The very limited stability field for romarchite, based on data presented by Séby et al. (Geochimica et Cosmochimica Acta, 65, 3041,3053, 2001), suggests that its presence on these artifacts may be the result of a kinetic effect. The universal appearance of this mineral on corroding tin suggests that it is a required step in the oxidation of pure tin to the final most stable phase of cassiterite. The stability of romarchite and its effectiveness as an agent of passivation can provide insight into not only the formation of tin oxides but the rate of tin corrosion. This can have significant implications in the field of artifact preservation as well as more widespread industrial applications. © 2004 Wiley Periodicals, Inc. [source]

Functions and pathophysiological roles of phospholipase D in the brain

JOURNAL OF NEUROCHEMISTRY, Issue 6 2005
Jochen Klein
Abstract Ten years after the isoforms of mammalian phospholipase D (PLD), PLD1 and 2, were cloned, their roles in the brain remain speculative but several lines of evidence now implicate these enzymes in basic cell functions such as vesicular trafficking as well as in brain development. Many mitogenic factors, including neurotransmitters and growth factors, activate PLD in neurons and astrocytes. Activation of PLD downstream of protein kinase C seems to be a required step for astroglial proliferation. The characteristic disruption of the PLD signaling pathway by ethanol probably contributes to the delay of brain growth in fetal alcohol syndrome. The post-natal increase of PLD activities concurs with synapto- and myelinogenesis in the brain and PLD is apparently involved in neurite formation. In the adult and aging brain, PLD activity has antiapoptotic properties suppressing ceramide formation. Increased PLD activities in acute and chronic neurodegeneration as well as in inflammatory processes are evidently due to astrogliosis and may be associated with protective responses of tissue repair and remodeling. ARF-regulated PLD participates in receptor endocytosis as well as in exocytosis of neurotransmitters where PLD seems to favor vesicle fusion by modifications of the shape and charge of lipid membranes. Finally, PLD activities contribute free choline for the synthesis of acetylcholine in the brain. Novel tools such as RNA interference should help to further elucidate the roles of PLD isoforms in brain physiology and pathology. [source]

Global optimization of mixed-integer nonlinear problems

AICHE JOURNAL, Issue 9 2000
C. S. Adjiman
Two novel deterministic global optimization algorithms for nonconvex mixed-integer problems (MINLPs) are proposed, using the advances of the ,BB algorithm for nonconvex NLPs of Adjiman et al. The special structure mixed-integer ,BB algorithm (SMIN-,BB) addresses problems with nonconvexities in the continuous variables and linear and mixed-bilinear participation of the binary variables. The general structure mixed-integer ,BB algorithm (GMIN-,BB) is applicable to a very general class of problems for which the continuous relaxation is twice continuously differentiable. Both algorithms are developed using the concepts of branch-and-bound, but they differ in their approach to each of the required steps. The SMIN-,BB algorithm is based on the convex underestimation of the continuous functions, while the GMIN-,BB algorithm is centered around the convex relaxation of the entire problem. Both algorithms rely on optimization or interval-based variable-bound updates to enhance efficiency. A series of medium-size engineering applications demonstrates the performance of the algorithms. Finally, a comparison of the two algorithms on the same problems highlights the value of algorithms that can handle binary or integer variables without reformulation. [source]

Überprüfung und Bewertung der seismischen Bemessungsgrößen nach DIN 19700 am Beispiel der Thüringer Talsperren

BAUTECHNIK, Issue 12 2004
Jochen Schwarz Dr.-Ing.
Durch die DIN 19700 werden Talsperren u. ä. Wasserbauwerke hinsichtlich ihrer Bedeutung, ihres Stauvolumens und Höhe (bzw. Stauhöhe) in unterschiedliche Klassen eingeteilt, verbunden mit unterschiedlichen Anforderungen an die Auslegung und Nachweisführung. Da die Talsperren in seismisch unterschiedlich aktiven Erdbebengebieten liegen, sind die Nachweisanforderungen in Abhängigkeit von der Gefährdung (Erdbebenzonen mit bestimmten Intensitätsintervallen) zu staffeln. Es wird untersucht, welche Anforderungen aus der Einführung DIN 19700 abzuleiten sind und wie auf Ebene der Bundesländer die praktische Umsetzung erfolgen kann. In diesem Zusammenhang wird die Thüringer Technische Anleitung Stauanlagen gesondert gewürdigt, die gegenüber der DIN veränderte Festlegungen beinhaltet. Im folgenden werden Grundzüge einer vereinheitlichten Vorgehensweise für den Freistaat Thüringen entwickelt und die notwendigen Bearbeitungsphasen erläutert. Sie sind so gestaltet, daß Synergieeffekte erreicht werden können und eine Übertragbarkeit auf die anderen Bundesländer gewährleistet ist. Examination and evaluation of seismic design criteria according to DIN 4149 by the example of the Thuringia dams. According to the new DIN 19700 dams and other water retaining structures are classified with respect to their storage capacity and height leading to differentiated demands on design and safety verification. Since the dams are located in quite different seismic regions, these demands have to reflect the level of seismic hazard (in terms of zones expressing different intensity intervals). The paper investigates the requirements connected with the introduction of DIN 19700 and the problems arising when implementing the code in a nation-wide scale acknowledging the federal system in Germany. In this context and due to some normative elements, deviating from DIN 19700, the Thuringian Technical Guide is considered more in detail. Basic contours of a unified strategy for the state of Thuringia and the required steps of action are presented. The procedure allows for effects of synergy by maintaining the transformability of the guidelines to other German States. [source]