452 research outputs found
Treating Intracranial Hypertension in Patients with Severe Traumatic Brain Injury during Neurointensive Care: New Features of Old Problems?
Despite the envisioned breakthrough prophesied for the end of the past century in healing brain injured patients, both clinicians and basic scientists are still struggling with this burden. In the past decades, intensive research has brought forward a plethora of different targets which—in part—have already been integrated in clinical routine directed at detailed monitoring, therapeutic interventions, and prevention of secondary deterioration. While intracellular targets remain obscure alterations on a larger scale as e. g., measured intracranial pressure (ICP), calculated cerebral perfusion pressure (CPP), and various imaging techniques are fundamental components of our present clinical understanding. At bedside, comprehension of pathophysiological loops and circuits of a given value (e. g., ICP) depends on individual knowledge, interpretation, and availability of additional diagnostic steps. As stated in the guidelines brought forward by the American Association of Neurological Surgeons and evaluated in various reports by the Cochrane Library we are still lacking prospective, randomized trials for the majority of the proposed diagnostic and therapeutic interventions. In this context, a recent meta-analysis even questioned the importance of ICP monitoring as we are lacking data from randomized controlled trials clarifying the role of ICP monitoring. The present review is to give an overview of various diagnostic and therapeutic possibilities based on reports published in the past 5 years to strengthen current approaches and nourish future well-designed investigations how to avoid and treat intracranial hypertensio
Controversial Issues Concerning Norepinephrine and Intensive Care Following Severe Traumatic Brain Injury
Norepinephrine and corresponding intra- and interorgan pathways are of clinical pathophysiologic and pharmacologic importance as exaggerated activation needs to be reduced and insufficient activation must be supported to prevent further deterioration and therapy-induced organ damage. This is of high relevance in critically ill patients in whom various norepinephrine-influenced organ systems are simultaneousy affected with varying degrees of tolerability and resistance to norepinephrine-induced cell damage and finds its maximal challenge in patients suffering from severe traumatic brain injury (TBI). This comprehensive review describes complex pathophysiologic interactions, including hemodynamic, microcirculatory, hormonal, metabolic, inflammatory, and thrombocytic alterations overshadowed by differential consequences of commonly applied pharmacological interventions following TBI. Overall, investigations published to date suggest that receptor-dependent effects of norepinephrine might predispose to complex evolving deterioration especially during intensive care which is characterized by differentiated complication-driven changes and specific complication-dependent needs. In this context, thrombocytes and leukocytes with their adrenergic receptors and differential norepinephric functional regulation are ideal candidates to influence all organs at once. Despite its secure integration of norepinephrine in clinical routine, future emphasis must be directed at unmasking, monitoring, and controlling possible receptor-mediated detrimental influences which could offset anticipated organ protectio
PCR amplification of DNA from malaria parasites on fixed and stained thick and thin blood films
Under some circumstances, polymerase chain reaction (PCR) amplification of deoxyribonucleic acid (DNA) from Plasmodium may become necessary from infections for which only blood slides are available. Established methods used for DNA preparation do not work in that case. We have developed a reliable and controlled method for DNA preparation from malaria parasites on fixed and stained blood films. 162 slides from 2 different locations, some stored for at least one year, have been analysed by PCR amplification of the polymorphic loci for MSA1 and MSA2. In 92% of microscopically positive slides, a PCR product could be detected using material derived from thick blood films. When thin blood films with scanty parasitaemia were used, a PCR product could be obtained with only 71% of samples. In all unsuccessful cases, DNA preparation was the limiting factor, which was controlled for by amplification of a control human templat
A Unified Picture of the FIP and Inverse FIP Effects
We discuss models for coronal abundance anomalies observed in the coronae of
the sun and other late-type stars following a scenario first introduced by
Schwadron, Fisk & Zurbuchen of the interaction of waves at loop footpoints with
the partially neutral gas. Instead of considering wave heating of ions in this
location, we explore the effects on the upper chromospheric plasma of the wave
ponderomotive forces. These can arise as upward propagating waves from the
chromosphere transmit or reflect upon reaching the chromosphere-corona
boundary, and are in large part determined by the properties of the coronal
loop above. Our scenario has the advantage that for realistic wave energy
densities, both positive and negative changes in the abundance of ionized
species compared to neutrals can result, allowing both FIP and Inverse FIP
effects to come out of the model. We discuss how variations in model parameters
can account for essentially all of the abundance anomalies observed in solar
spectra. Expected variations with stellar spectral type are also qualitatively
consistent with observations of the FIP effect in stellar coronae.Comment: 25 pages, 4 figures, submitted to Ap
Comparison of bending stiffness of cross-laminated solid timber derived by modal analysis of full panels and by bending tests ofstrip-shaped specimens
The design of cross-laminated solid timber (CLT) as load-bearing plates is mainly governed by serviceability criterions like maximal deflection and susceptibility to vibration. Hence, predicting the respective behavior of such plates requires accurate information about their elastic properties. According to product standards, the bending stiffness of CLT has to be assessed from 4-point bending tests of strip-shaped specimens, cut from the CLT panels. By comparing elastic properties of CLT derived by means of modal analysis of full panels with the results of bending tests on 100mm and 300mm wide strip-shaped specimens it is shown, that by testing single 100mm wide strip-shaped specimens bending stiffness of full panels cannot be assessed correctly, whereas single 300mm wide strips or averages of 5 to 6 100mm wide strip-shaped specimens lead to acceptable results. Hence, strip-shaped specimens should only be used in the course of factory quality control or when assessing the bending stiffness of parts of CLT panels used as beam-like load-bearing elements but not to derive bending stiffness of gross CLT panels. Verification by carrying out static bending tests of gross CLT panels under different loading situations showed that alternatively to tests on strip-shaped specimens or estimations with the compound theory, the overall stiffness properties of CLT can be derived directly by a modal analysis of full-size panel
Thiol-gelatin-norbornene bioink for laser‐based high‐definition bioprinting
Two-photon polymerization (2PP) is a lithography-based 3D printing method allowing the fabrication of 3D structures with sub-micrometer resolution. This work focuses on the characterization of gelatin-norbornene (Gel-NB) bioinks which enables the embedding of cells via 2PP. The high reactivity of the thiol-ene system allows 2PP processing of cell-containing materials at remarkably high scanning speeds (1000 mm s(-1)) placing this technology in the domain of bioprinting. Atomic force microscopy results demonstrate that the indentation moduli of the produced hydrogel constructs can be adjusted in the 0.2-0.7 kPa range by controlling the 2PP processing parameters. Using this approach gradient 3D constructs are produced and the morphology of the embedded cells is observed in the course of 3 weeks. Furthermore, it is possible to tune the enzymatic degradation of the crosslinked bioink by varying the applied laser power. The 3D printed Gel-NB hydrogel constructs show exceptional biocompatibility, supported cell adhesion, and migration. Furthermore, cells maintain their proliferation capacity demonstrated by Ki-67 immunostaining. Moreover, the results demonstrate that direct embedding of cells provides uniform distribution and high cell loading independently of the pore size of the scaffold. The investigated photosensitive bioink enables high-definition bioprinting of well-defined constructs for long-term cell culture studies
Möglichkeiten und Maßnahmen zur Wahrung und Steigerung der Wettbewerbsfähigkeit der Baden-Württembergischen Wertpapierbörse zu Stuttgart
Die Börsenstrukturen befinden sich international in einer Phase dynamischer Veränderungen.
Der härter gewordene Wettbewerb hinterläßt bei den großen nationalen Börsen tiefe Spuren und führt zu Anpassungsmaßnahmen, die vor allem in der technischen Neuorganisation des Börsenhandels und in der Erweiterung der Produktpalette ihren Ausdruck finden. Regionalbörsen
wie die Baden-Württembergische Wertpapierbörse zu Stuttgart sind dabei einem noch stärkeren Wettbewerbsdruck ausgesetzt, da neben die internationale Konkurrenz noch die
Konkurrenz der deutschen Börsen untereinander tritt.
Das vorliegende Gutachten, das vom Staatsministerium Baden-Württemberg in Auftrag gegeben wurde, widmet sich speziell der Erarbeitung von Vorschlägen, die der Wahrung und Steigerung
der Wettbewerbsfähigkeit der Stuttgarter Wertpapierbörse dienen
Versuche und Berechnungen an allseitig gelagerten 3-schichtigen Brettsperrholzplatten
Zusammenfassung: Im Rahmen eines umfangreichen Forschungsprojektes wurden Brettsperrholzplatten (BSP), die im Bauwesen auch als statisch tragende Bauteile eingesetzt werden, untersucht. Quadratische dreischichtige BSP mit Seitenlänge 2,5m und Dicke 70mm von zwei Herstellern wurden statisch senkrecht zur Plattenebene bis zum Bruch geprüft. Untersucht wurden drei verschiedene Laststellungen und zwei Querschnittsaufbauten. Ultraschallmessungen an den Einzelschichten vor der Verklebung dienten zur Schätzung der Elastizitätsmoduln der Einzelschichten. Die Elastizitätsmoduln und Festigkeiten der verklebten Platten parallel und senkrecht zur Faserrichtung der Deckschicht wurden zusätzlich in Balkenversuchen ermittelt. Ergebnisse und Erkenntnisse aus den Ultraschallmessungen, Balken- und Plattenversuchen werden präsentiert. Verschiedenste Balken- und Platten-Berechnungsmodelle für die BSP werden vorgestellt. Die Versuchsresultate werden mit den Berechnungen verglichen. Ein Berechnungsvorschlag für die Praxis wird präsentier
Möglichkeiten und Maßnahmen zur Wahrung und Steigerung der Wettbewerbsfähigkeit der Baden-Württembergischen Wertpapierbörse zu Stuttgart
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