Oligodeoxynucleotide-polypeptide block copolymers

Synthesis and characterization of monodisperse oligonucleotide-polypeptide di- and triblock copolymers are described. These block copolymers are promising building blocks for the formation of defined structures by sequential DNA self-assembly. The oligonucleotide sequences (ODN, 46 bases) obtained from standard solid phase synthesis were designed to form four-arm DNA junctions. The hybridization of the four single stranded oligonucleotides at room temperature to a stable four-arm junction is selective and quantitative. The junctions exhibit good thermal stability as proven by polyacrylamide gel electrophoresis (PAGE) and UV analysis. The second block consists of monodisperse elastin-like polypeptides (ELPs) with a pentapeptide repeat unit of (Val-Pro-Gly-Val-Gly) synthesized by genetic engineering. ODN-ELP diblock copolymers were obtained either by thiol coupling or by activated ester chemistry. Taking advantage of the endgroup control of both components (ODN, ELP), combination of the two different synthetic approaches leads to the synthesis of ODN-ELP-ODN triblock copolymers. Dynamic light scattering measurements of the single components and the synthesized diblock copolymers reveal their monodispersity. Hybridization of four ODN-ELP diblock copolymers carrying the four junction sequences shows quantitative self-assembly. In conclusion, this work provides the first example of the synthesis of perfectly defined ODN-ELP block copolymers and their potential use in DNA self-assembly.

Validation of a new method to assess the long-term Hypothalamic-Pituitary-Adrenal Activity using hair glucocorticoids as biomarkers. - Studies on pigs and laboratory Sprague-Dawley Rats

The evaluation of chronic activity of the hypothalamic-pituitary-adrenal (HPA) axis is critical for determining the impact of chronic stressful situations. The potential use of hair glucocorticoids as a non-invasive, retrospective, biomarker of long term HPA activity is of great interest, and it is gaining acceptance in humans and animals. However, there are still no studies in literature examining hair cortisol concentration in pigs and corticosterone concentration in laboratory rodents. Therefore, we developed and validated, for the first time, a method for measuring hair glucocorticoids concentration in commercial sows and in Sprague-Dawley rats. Our preliminary data demonstrated: 1) a validated and specific washing protocol and extraction assay method with a good sensitivity in both species; 2) the effect of the reproductive phase, housing conditions and seasonality on hair cortisol concentration in sows; 3) similar hair corticosterone concentration in male and female rats; 4) elevated hair corticosterone concentration in response to chronic stress manipulations and chronic ACTH administration, demonstrating that hair provides a good direct index of HPA activity over long periods than other indirect parameters, such adrenal or thymus weight. From these results we believe that this new non-invasive tool needs to be applied to better characterize the overall impact in livestock animals and in laboratory rodents of chronic stressful situations that negatively affect animals welfare. Nevertheless, further studies are needed to improve this methodology and maybe to develop animal models for chronic stress of high interest and translational value in human medicine.

Etablierung und Optimierung von Therapeutischem Drug Monitoring für die Psychopharmakotherapie von Patienten mit Substanzabhängigkeit

Therapeutisches Drug Monitoring (TDM) findet Anwendung in der Therapie mit Immunosuppressiva, Antibiotika, antiretroviraler Medikation, Antikonvulsiva, Antidepressiva und auch Antipsychotika, um die Effizienz zu steigern und das Risiko von Intoxikationen zu reduzieren. Jedoch ist die Anwendung von TDM für Substanzen, die Einsatz finden in der Rückfallprophylaxe, der Substitution oder dem Entzug von Abhängigkeitserkrankungen nicht etabliert. Für diese Arbeit wurde im ersten Schritt eine sensitive Rating-Skala mit 22 Items entwickelt, mit Hilfe derer der theoretische Nutzen von TDM in der Pharmakotherapie von substanzbezogenen Abhängigkeitserkrankungen auf der Basis von pharmakologischen Eigenschaften der Medikamente und von Patientencharakteristika evaluiert wurde. Die vorgenommene Einschätzung zeigte für Bupropion, Buprenorphin, Disulfiram (oder einen Metaboliten), Methadon (chirale Bestimmung wenn möglich) und Naltrexon einen potentiellen Nutzen von TDM.rnFür die meisten Medikamente, die zur Behandlung von Abhängigkeitserkrankungen zugelassen sind, fehlen valide Messverfahren für TDM. Im Alltag werden überwiegend Drogen Screening-Tests in Form immunologischer Schnelltests angewendet. Für die Anwendung von TDM wurden in dieser Arbeit chromatographische Verfahren für die Bestimmung von Naltrexon und 6β-Naltrexol, Bupropion und Hydroxybupropion sowie R,S-Methadon und R,S-2-Ethyliden-1,5-dimethyl-3,3-diphenylpyrrolidin entwickelt, optimiert und validiert. Es handelt sich dabei HPLC-UV-Methoden mit Säulenschaltung sowie zur Bestimmung von Naltrexon und 6β-Naltrexol zusätzlich eine LC-MS/MS-Methode. Voraussetzung für die Interpretation der Plasmaspiegel ist im Wesentlichen die Kenntnis eines therapeutischen Bereichs. Für Naltrexon und seinen aktiven Metaboliten 6β-Naltrexol konnte eine signifikante Korrelation zwischen dem auftretenden Craving und der Summenkonzentration gefunden werden. Mittels Receiver-Operation-Characteristics-Kurven-Analyse wurde ein Schwellenwert von 16,6 ng/ml ermittelt, oberhalb dessen mit einem erhöhten Ansprechen gerechnet werden kann. Für Levomethadon wurde bezüglich der Detoxifikationsbehandlung ein Zusammenhang in der prozentualen Reduktion des Plasmaspiegels und den objektiven und subjektiven Entzugssymptomen gefunden. rnDoch nicht nur die Wirkstoffe, sondern auch das Patientenmerkmal substanzbezogene Abhängigkeit wurde charakterisiert, zum einen bezüglich pharmakokinetischer Besonderheiten, zum anderen in Hinsicht auf die Therapietreue (Adhärenz). Für Patienten mit komorbider Substanzabhängigkeit konnte eine verminderte Adhärenz unabhängig von der Hauptdiagnose gezeigt werden. Die Betrachtung des Einflusses von veränderten Leberwerten zeigt für komorbide Patienten eine hohe Korrelation mit dem Metabolisiererstatus, nicht aber für Patienten ohne Substanzabhängigkeit.rnÜbergeordnetes Ziel von TDM ist die Erhöhung der Therapiesicherheit und die Steigerung der Therapieeffizienz. Dies ist jedoch nur möglich, wenn TDM im klinischen Alltag integriert ist und korrekt eingesetzt wird. Obwohl es klare Evidenz für TDM von psychiatrischer Medikation gibt, ist die Diskrepanz zwischen Laborempfehlung und der klinischen Umsetzung hoch. Durch Intensivierung der interdisziplinären Zusammenarbeit zwischen Ärzten und Labor, der Entwicklung von interaktivem TDM (iTDM), konnte die Qualität der Anwendung von TDM verbessert und das Risiko von unerwünschten Arzneimittelwirkungen vermindert werden. rnInsgesamt konnte durch die eigenen Untersuchungen gezeigt werden, dass TDM für die medikamentöse Einstellung von Patienten mit Abhängigkeitserkrankung sinnvoll ist und dass optimales TDM eine interdisziplinäre Zusammenarbeit erfordert.rn

In vitro modulation of epileptiform activity in the hippocampal formation of immature rodents by GABAergic antagonists, dopamine and methylxanthines

Während des frühen Lebens stellen epileptische Anfälle schwere neurologische Zustände dar, weil sie ein großer Risikofaktor für die Manifestation der Epilepsie sind und eine hohe pharmakologische Resistenz zeigen. In meiner Doktorarbeit konzentrierte ich mich auf die Frage, wie verschiedene Neurotransmitter-Systeme und klinisch verwendete Medikamente epileptiforme Entladungen im perinatalen Hippocampus beeinflussen. rnIm ersten Teil meines Projektes untersuchte ich die Wirkung von GABA-Antagonisten und Modulatoren, die zwischen phasischen und tonischen GABAergen Strömen differenzieren, auf Feldpotentialaktivität in Hippocampusschnitten. Diese Experimente zeigten, dass im unreifen Hippocampus synaptische GABAerge Aktivität benötigt wird, um die Erregbarkeit zu begrenzen, während tonische GABAerge Ströme die Erregbarkeit verstärken können. Dies könnte darauf hinweisen, dass Antiepileptika mit einer höheren Spezifität für synaptische GABAA-Rezeptoren wirksamer zur Behandlung von epileptischen Anfällen bei Neugeborenen sein können. rnUm den Einfluss von Dopamin auf die Erregbarkeit des unreifen Hippocampus herauszufinden, untersuchte ich im zweiten Teil meiner Arbeit die Wirkung von verschiedenen Dopaminkonzentrationen und spezifische Agonisten und Antagonisten der Dopamin-Rezeptor-Subtypen auf epileptiforme Entladungen. Diese Experimente zeigten, dass niedrige Dopamin Konzentrationen eine antikonvulsive Wirkung haben, welche vom D2-ähnliche-Rezeptor-Agonisten Quinpirol nachgeahmt werden kann, während höhere Dopamin-Konzentrationen eine prokonvulsive Wirkung über Aktivierung von D1-ähnlichen Rezeptoren hervorrufen. Obwohl unsere Untersuchungen eine mögliche Verwendung von D2-ähnlichen Rezeptor-Agonisten zur Kontrolle epileptischer Anfälle in Neugeborenen nahelegen, müssen mögliche negative Auswirkungen von DAergen Agonisten und Antagonisten auf die neuronale Entwicklung berücksichtigt werden.rnIm dritten Teil meiner Arbeit untersuchte ich welche Konzentrationen von Methylxanthinen epileptische Anfälle in Hippocampuspreparationen auslösen die synaptische Übertragungen verändern können. Diese Experimente zeigten, dass sowohl Theophyllin als auch Koffein in höheren Konzentrationen die basale synaptische Übertragungen in der CA1-Region des Hippocampus modifizieren und epileptiforme Entladungen provozieren. Die Auswirkungen auf die postsynaptischen Antworten und spontanen epileptiformen Entladungen durch Koffein waren weniger ausgeprägt, was darauf hindeutet, dass diese Substanz potentiell vorteilhafter für therapeutische Anwendungen bei Frühgeborenen sein kann. rnZusammenfassend bereichern die Ergebnisse meiner Studie erheblich unser Wissen über die zugrunde liegenden Mechanismen epileptiformer Aktivität im unreifen Hippocampus und den therapeutischen Einsatz von Methylxanthinen und Pharmaka, die auf das GABAerge und DArge System einwirken.rnrn

Etablierung eines humanisierten Mausmodells zur In-vivo-Analyse von DC-adressierenden Nanopartikeln

In dieser Arbeit wurde zunächst ein humanisiertes Mausmodell entwickelt für die Analyse von humanen DCs in vivo. Darüber hinaus wurden erste Versuche mit Nanopartikelbeladenen DCs durchgeführt, mit der Intention, durch diese Kombination humane DCs zu untersuchen. Es wurden immunsupprimierte NOD/LtSz-scid IL2R (NSG) Mäuse verwendet und mit humanen CD34+ PBSCs transplantiert. Es wurden insgesamt 14 Modelle getestet, mit einer durchschnittlichen Humanisierungsrate von 76 %. In allen Modellen konnten ab Woche sechs nach Transplantation humane CD45+ Zellen sowie humane Bund NK-Zellen und CD14+ Monozyten gefunden werden. Darüber hinaus waren myeloide DC-Vorläuferzellen, konventionelle HLA DR CD11c DCs (cDCs) und plasmazytoide DCs (pDCs) vorhanden. Humane T-Zellen konnten nicht vor Woche 18 nach Transplantation beobachtet werden. Neben der Rekonstitution humaner DCs in peripheren Organen, wurde ebenfalls nach gewebsständigen DCs, insbesondere den Langerhans Zellen (LCs) der Epidermis geschaut. Waren humane LC vorhanden, konnten diese ab Woche zwölf nach Transplantation in der murinen Epidermis detektiert werden. Diese waren konstant bis in Woche 30 nach Transplantation nachweisbar. In Hinblick auf die Etablierung der DCs in diesem humanisierten Mausmodells wurden verschiedene Einflussgrößen getestet. IL-7 führte zu keiner veränderten Hämatopoese, wohingegen Flt3L zu einer Zunahme von CD14+ Monozyten und cDCs führte. Darüber hinaus konnte eine drastische Abnahmernhumaner B-Zellen beobachtet werden. Es zeigte sich, dass der Zeitpunkt der Flt3LrnApplikation einen entscheidenen Faktor für den Effekt von Flt3L auf die Rekonstitution humaner Zellen darstellt. Für die in dieser Arbeit durchgeführten funktionellen in vivo Studien, wurden humanisierten Mäusen alloreaktive CD8+ T-Zellen appliziert. Somit sollte die Funktionalität der rekonstituierten humanen APCs getestet werden. Es wurde deutlich, dass Monozyten und DCs ihre Funktionalität erst ab Woche 14 nach Transplantation zu entwickeln schienen,rnwohingegen B-Zellen bereits zu früheren Zeitpunkten als Zielzellen für die alloreaktiven T-Zellen dienten. Dies wurde durch den Rückgang der jeweiligen Zellen nach Applikation der T-Zellen sichtbar. Zu erwähnen ist, dass das Anwachsen einer humanen Hämatopoese stark spenderabhängig ist und somit keine allgemeingültigen Aussagen hinsichtlich der in vivo Funktion getroffen werden können. Um im Gewebe verbliebende APCs zu manipulieren gibt es verschiedene Möglichkeiten. Im Rahmen dieser Arbeit wurden auf Polystyren-basierende Nanopartikel getestet. Die verwendeten Partikel hatten eine Größe von 80 bis 160 nm und waren unfunktionalisiert oder mit Amino- bzw. Carboxy-Gruppen versehen. Zusätzlich wurden die Partikel mit BODIPY (Durchflusszytometrie und kLSM-Messungen), einem Infrarotnahem Farbstoff IR 780 (BFI-Messungen) und Platin (in vivo Messungen) beladen. Der Carboxy-funktionalisierte Partikel zeigte den geringsten Einfluss auf die Vitalität von humanen DCs, wohingegen der Amino-funktionalisierte Partikel bei steigender Konzentration toxisch wirkte. Bei unfunktionalisierten Partikeln stieg die Toxizität bei zunehmender Konzentration. Hinsichtlich der Expression diverser DC spezifischer Oberflächenmoleküle nach Beladung mit Nanopartikeln zeigte sich, dass allein der unfunktionalisierte, mit Lutensol AT50 hergestellte Partikel zu einer leichten Hochregulation von MHC-Klasse-II Molekülen führte. Die Expression von CD86 wurde im Gegenzug nur durch die Beladung mit den Amino-, bzw. Carboxy funktionalisierten Partikeln und dem unfunktionalisierten, mit SDS hergestellten Partikel leicht gesteigert. Trotz der teilweise leicht veränderten Expression von Oberflächenmarkern, konnte mit Hilfe von IFN-g ELISpots keine Beeinflussungrnder Funktion als APCs von Nanopartikel-beladenen DCs beobachtet werden. In den in vivo Untersuchungen zeigten alle vier Partikel eine konstante Zirkulation imrnOrganismus und konnten bis 96 h nach Applikation nachgewiesen werden. Alle Partikel konnten primär in der Leber detektiert werden, wobei der unfunktionalisierte, mit Lutensol AT50 hergestelle Partikel das weiteste Verbreitungsmuster zeigte. Erste Versuche im humanisierten Mausmodell zeigten keine Beeinflussung der Verteilung und Kinetik von Nanopartikeln durch die humane Hämatopoese. Mit dem in dieser Arbeit etablierten humanisierten Mausmodell ist es möglich, die Entwicklung, Differenzierung, Aktivierung und Funktionalität humaner DCs in vivo zu untersuchen. Darüber hinaus kann das gezielte Adressieren von DCs in vivo analysiert werden, was sowohl die Möglichkeit der Manipulation von DCs zur Vermeidung einer akuten GvHD bietet als auch Verwendung in anderen DC-vermittelten Therapien (z.B.Vakzinationsstudien) findet.

Bioactivity of extracts from extremophile microalgae Coccomyxa sp. on chloride cells in operculum tissue of Fundulus heteroclitus

Microalgae have been studied because of their great potential as a source of new compounds with important value for biotechnology and to understand their strategies of survival in extreme environments. The microalgae Coccomyxa sp., studied in this thesis, is a poly-extremophile witch was isolated from the acid mine drainage of S. Domingos mine. This environment is characterized by low pH (<3) and high concentration of metals, such as copper and iron. The main purpose of the present work was to evaluate the potential bioactivity in an ex-vivo animal model (Fundulus heteroclitus), and expression on selected genes, of cellular extracts obtained from cultures of Coccomyxa sp. at pH 7 without or with exposure to copper (0.6mM Cu²+). The extracts of Coccomyxa sp. cultured at pH 7 exposed to copper show a great potential to be used as epithelial NKCC inhibitors, revealing their potential use as diuretics, but did not show significant effects on gene expression. Coccomyxa sp. could be a good source of cellular extracts with a great potential to be used in pharmaceutical and biotechnology industries.

Hematopoietic stem cell transplantation in Switzerland: a comprehensive quality control report on centre effect

QUESTIONS UNDER STUDY / PRINCIPLES: Interest groups advocate centre-specific outcome data as a useful tool for patients in choosing a hospital for their treatment and for decision-making by politicians and the insurance industry. Haematopoietic stem cell transplantation (HSCT) requires significant infrastructure and represents a cost-intensive procedure. It therefore qualifies as a prime target for such a policy. METHODS: We made use of the comprehensive database of the Swiss Blood Stem Cells Transplant Group (SBST) to evaluate potential use of mortality rates. Nine institutions reported a total of 4717 HSCT - 1427 allogeneic (30.3%), 3290 autologous (69.7%) - in 3808 patients between the years 1997 and 2008. Data were analysed for survival- and transplantation-related mortality (TRM) at day 100 and at 5 years. RESULTS: The data showed marked and significant differences between centres in unadjusted analyses. These differences were absent or marginal when the results were adjusted for disease, year of transplant and the EBMT risk score (a score incorporating patient age, disease stage, time interval between diagnosis and transplantation, and, for allogeneic transplants, donor type and donor-recipient gender combination) in a multivariable analysis. CONCLUSIONS: These data indicate comparable quality among centres in Switzerland. They show that comparison of crude centre-specific outcome data without adjustment for the patient mix may be misleading. Mandatory data collection and systematic review of all cases within a comprehensive quality management system might, in contrast, serve as a model to ascertain the quality of other cost-intensive therapies in Switzerland.

SDHB loss predicts malignancy in pheochromocytomas/sympathethic paragangliomas, but not through hypoxia signalling

Prediction of malignant behaviour of pheochromocytomas/sympathetic paragangliomas (PCCs/PGLs) is very difficult if not impossible on a histopathological basis. In a familial setting, it is well known that succinate dehydrogenase subunit B (SDHB)-associated PCC/PGL very often metastasise. Recently, absence of SDHB expression as measured through immunohistochemistry was shown to be an excellent indicator of the presence of an SDH germline mutation in PCC/PGL. SDHB loss is believed to lead to tumour formation by activation of hypoxia signals. To clarify the potential use of SDHB immunohistochemistry as a marker of malignancy in PCC/PGL and its association with classic hypoxia signalling we examined SDHB, hypoxia inducible factor-1 (Hif-1 ) and its targets CA-9 and GLUT-1 expression on protein level using immunohistochemistry on a tissue micro array on a series of familial and sporadic tumours of 115 patients. Survival data was available for 66 patients. SDHB protein expression was lost in the tumour tissue of 12 of 99 patients. Of those 12 patients, 5 had an SDHB germline mutation, in 4 patients no germline mutation was detected and mutational status remained unknown in parts in 3 patients. Loss of SDHB expression was not associated with increased classic hypoxia signalling as detected by Hif-1 , CA-9 or GLUT-1 staining. Loss of SDHB expression was associated with an adverse outcome. The lack of correlation of SDHB loss with classic hypoxia signals argues against the current hypoxia hypothesis in malignant PCC/PGL. We suggest SDHB protein loss as a marker of adverse outcome both in sporadic and in familial PCC/PGL.

Chest pulse-wave velocity: a novel approach to assess arterial stiffness

Pulse-wave velocity (PWV) is considered as the gold-standard method to assess arterial stiffness, an independent predictor of cardiovascular morbidity and mortality. Current available devices that measure PWV need to be operated by skilled medical staff, thus, reducing the potential use of PWV in the ambulatory setting. In this paper, we present a new technique allowing continuous, unsupervised measurements of pulse transit times (PTT) in central arteries by means of a chest sensor. This technique relies on measuring the propagation time of pressure pulses from their genesis in the left ventricle to their later arrival at the cutaneous vasculature on the sternum. Combined thoracic impedance cardiography and phonocardiography are used to detect the opening of the aortic valve, from which a pre-ejection period (PEP) value is estimated. Multichannel reflective photoplethysmography at the sternum is used to detect the distal pulse-arrival time (PAT). A PTT value is then calculated as PTT = PAT - PEP. After optimizing the parameters of the chest PTT calculation algorithm on a nine-subject cohort, a prospective validation study involving 31 normo- and hypertensive subjects was performed. 1/chest PTT correlated very well with the COMPLIOR carotid to femoral PWV (r = 0.88, p < 10 (-9)). Finally, an empirical method to map chest PTT values onto chest PWV values is explored.

Metallic copper as an antimicrobial surface

Bacteria, yeasts, and viruses are rapidly killed on metallic copper surfaces, and the term "contact killing" has been coined for this process. While the phenomenon was already known in ancient times, it is currently receiving renewed attention. This is due to the potential use of copper as an antibacterial material in health care settings. Contact killing was observed to take place at a rate of at least 7 to 8 logs per hour, and no live microorganisms were generally recovered from copper surfaces after prolonged incubation. The antimicrobial activity of copper and copper alloys is now well established, and copper has recently been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. In several clinical studies, copper has been evaluated for use on touch surfaces, such as door handles, bathroom fixtures, or bed rails, in attempts to curb nosocomial infections. In connection to these new applications of copper, it is important to understand the mechanism of contact killing since it may bear on central issues, such as the possibility of the emergence and spread of resistant organisms, cleaning procedures, and questions of material and object engineering. Recent work has shed light on mechanistic aspects of contact killing. These findings will be reviewed here and juxtaposed with the toxicity mechanisms of ionic copper. The merit of copper as a hygienic material in hospitals and related settings will also be discussed.

Susceptibility of Aethina tumida (Coleoptera: Nitidulidae) Larvae and Pupae to Entomopathogenic Nematodes

In this study, we evaluated the potential use of entomopathogenic nematodes as a control for the beetle Aethina tumida Murray (Coleoptera: Nitidulidae). In particular, we conducted 1) four screening bioassays to determine nematode (seven species, 10 total strains tested) and application level effects on A. tumida larvae and pupae, 2) a generational persistence bioassay to determine whether single inoculations with nematodes would control multiple generations of A. tumida larvae in treated soil, and 3) a field bioassay to determine whether the nematodes would remain efficacious in the field. In the screening bioassays, nematode efficacy varied significantly by tested nematode and the infective juvenile (IJ) level at which they were applied. Although nematode virulence was moderate in screening bioassays 1-3 (0 - 68% A. tumida mortality), A. tumida mortality approached higher levels in screening bioassay 4 (nearly 100% after 39 d) that suggest suitable applicability of some of the test nematodes as field controls for A. tumida. In the generational persistence bioassay, Steinernema Hobrave Cabanillas, Poinar & Raulston 7-12 strain and Heterorhabditis indica Poinar, Karunaka & David provided adequate A. tumida control for 19 wk after a single soil inoculation (76-94% mortality in A. tumida pupae). In the field bioassay, the same two nematode species also showed high virulence toward pupating A. tumida (88-100%) mortality. Our data suggest that nematode use may be an integral component of an integrated pest management scheme aimed at reducing A. tumida populations in bee colonies to tolerable levels.

Diffusion-driven transport in clayrock formations

Clay mineral-rich sedimentary formations are currently under investigation to evaluate their potential use as host formations for installation of deep underground disposal facilities for radioactive waste (e.g. Boom Clay (BE), Opalinus Clay (CH), Callovo-Oxfordian argillite (FR)). The ultimate safety of the corresponding repository concepts depends largely on the capacity of the host formation to limit the flux towards the biosphere of radionuclides (RN) contained in the waste to acceptably low levels. Data for diffusion-driven transfer in these formations shows extreme differences in the measured or modelled behaviour for various radionuclides, e. g. between halogen RN (Cl-36, I-129) and actinides (U-238,U-235, Np-237, Th-232, etc.), which result from major differences between RN of the effects on transport of two phenomena: diffusion and sorption. This paper describes recent research aimed at improving understanding of these two phenomena, focusing on the results of studies carried out during the EC Funmig IP on clayrocks from the above three formations and from the Boda formation (HU). Project results regarding phenomena governing water, cation and anion distribution and mobility in the pore volumes influenced by the negatively-charged surfaces of clay minerals show a convergence of the modelling results for behaviour at the molecular scale and descriptions based on electrical double layer models. Transport models exist which couple ion distribution relative to the clay-solution interface and differentiated diffusive characteristics. These codes are able to reproduce the main trends in behaviour observed experimentally, e.g. D-e(anion) < D-e(HTO) < D-e(cation) and D-e(anion) variations as a function of ionic strength and material density. These trends are also well-explained by models of transport through ideal porous matrices made up of a charged surface material. Experimental validation of these models is good as regards monovalent alkaline cations, in progress for divalent electrostatically-interacting cations (e.g. Sr2+) and still relatively poor for 'strongly sorbing', high K-d cations. Funmig results have clarified understanding of how clayrock mineral composition, and the corresponding organisation of mineral grain assemblages and their associated porosity, can affect mobile solute (anions, HTO) diffusion at different scales (mm to geological formation). In particular, advances made in the capacity to map clayrock mineral grain-porosity organisation at high resolution provide additional elements for understanding diffusion anisotropy and for relating diffusion characteristics measured at different scales. On the other hand, the results of studies focusing on evaluating the potential effects of heterogeneity on mobile species diffusion at the formation scale tend to show that there is a minimal effect when compared to a homogeneous property model. Finally, the results of a natural tracer-based study carried out on the Opalinus Clay formation increase confidence in the use of diffusion parameters measured on laboratory scale samples for predicting diffusion over geological time-space scales. Much effort was placed on improving understanding of coupled sorption-diffusion phenomena for sorbing cations in clayrocks. Results regarding sorption equilibrium in dispersed and compacted materials for weakly to moderately sorbing cations (Sr2+, Cs+, Co2+) tend to show that the same sorption model probably holds in both systems. It was not possible to demonstrate this for highly sorbing elements such as Eu(III) because of the extremely long times needed to reach equilibrium conditions, but there does not seem to be any clear reason why such elements should not have similar behaviour. Diffusion experiments carried out with Sr2+, Cs+ and Eu(III) on all of the clayrocks gave mixed results and tend to show that coupled diffusion-sorption migration is much more complex than expected, leading generally to greater mobility than that predicted by coupling a batch-determined K-d and Ficks law based on the diffusion behaviour of HTO. If the K-d measured on equivalent dispersed systems holds as was shown to be the case for Sr, Cs (and probably Co) for Opalinus Clay, these results indicate that these cations have a D-e value higher than HTO (up to a factor of 10 for Cs+). Results are as yet very limited for very moderate to strongly sorbing species (e.g. Co(II), Eu(III), Cu(II)) because of their very slow transfer characteristics. (C) 2011 Elsevier Ltd. All rights reserved.

Identifying mechanisms of treatment effects and recovery in rehabilitation of schizophrenia: longitudinal analytic methods

The longitudinal dimension of schizophrenia and related severe mental illness is a key component of theoretical models of recovery. However, empirical longitudinal investigations have been underrepresented in the psychopathology of schizophrenia. Similarly, traditional approaches to longitudinal analysis of psychopathological data have had serious limitations. The utilization of modern longitudinal methods is necessary to capture the complexity of biopsychosocial models of treatment and recovery in schizophrenia. The present paper summarizes empirical data from traditional longitudinal research investigating recovery in symptoms, neurocognition, and social functioning. Studies conducted under treatment as usual conditions are compared to psychosocial intervention studies and potential treatment mechanisms of psychosocial interventions are discussed. Investigations of rehabilitation for schizophrenia using the longitudinal analytic strategies of growth curve and time series analysis are demonstrated. The respective advantages and disadvantages of these modern methods are highlighted. Their potential use for future research of treatment effects and recovery in schizophrenia is also discussed.

Growth, modification and integration of carbon nanotubes into molecular electronics

Molecules are the smallest possible elements for electronic devices, with active elements for such devices typically a few Angstroms in footprint area. Owing to the possibility of producing ultrahigh density devices, tremendous effort has been invested in producing electronic junctions by using various types of molecules. The major issues for molecular electronics include (1) developing an effective scheme to connect molecules with the present micro- and nano-technology, (2) increasing the lifetime and stabilities of the devices, and (3) increasing their performance in comparison to the state-of-the-art devices. In this work, we attempt to use carbon nanotubes (CNTs) as the interconnecting nanoelectrodes between molecules and microelectrodes. The ultimate goal is to use two individual CNTs to sandwich molecules in a cross-bar configuration while having these CNTs connected with microelectrodes such that the junction displays the electronic character of the molecule chosen. We have successfully developed an effective scheme to connect molecules with CNTs, which is scalable to arrays of molecular electronic devices. To realize this far reaching goal, the following technical topics have been investigated. 1. Synthesis of multi-walled carbon nanotubes (MWCNTs) by thermal chemical vapor deposition (T-CVD) and plasma-enhanced chemical vapor deposition (PECVD) techniques (Chapter 3). We have evaluated the potential use of tubular and bamboo-like MWCNTs grown by T-CVD and PE-CVD in terms of their structural properties. 2. Horizontal dispersion of MWCNTs with and without surfactants, and the integration of MWCNTs to microelectrodes using deposition by dielectrophoresis (DEP) (Chapter 4). We have systematically studied the use of surfactant molecules to disperse and horizontally align MWCNTs on substrates. In addition, DEP is shown to produce impurityfree placement of MWCNTs, forming connections between microelectrodes. We demonstrate the deposition density is tunable by both AC field strength and AC field frequency. 3. Etching of MWCNTs for the impurity-free nanoelectrodes (Chapter 5). We show that the residual Ni catalyst on MWCNTs can be removed by acid etching; the tip removal and collapsing of tubes into pyramids enhances the stability of field emission from the tube arrays. The acid-etching process can be used to functionalize the MWCNTs, which was used to make our initial CNT-nanoelectrode glucose sensors. Finally, lessons learned trying to perform spectroscopic analysis of the functionalized MWCNTs were vital for designing our final devices. 4. Molecular junction design and electrochemical synthesis of biphenyl molecules on carbon microelectrodes for all-carbon molecular devices (Chapter 6). Utilizing the experience gained on the work done so far, our final device design is described. We demonstrate the capability of preparing patterned glassy carbon films to serve as the bottom electrode in the new geometry. However, the molecular switching behavior of biphenyl was not observed by scanning tunneling microscopy (STM), mercury drop or fabricated glassy carbon/biphenyl/MWCNT junctions. Either the density of these molecules is not optimum for effective integration of devices using MWCNTs as the nanoelectrodes, or an electroactive contaminant was reduced instead of the ionic biphenyl species. 5. Self-assembly of octadecanethiol (ODT) molecules on gold microelectrodes for functional molecular devices (Chapter 7). We have realized an effective scheme to produce Au/ODT/MWCNT junctions by spanning MWCNTs across ODT-functionalized microelectrodes. A percentage of the resulting junctions retain the expected character of an ODT monolayer. While the process is not yet optimized, our successful junctions show that molecular electronic devices can be fabricated using simple processes such as photolithography, self-assembled monolayers and dielectrophoresis.

Ultrasound-guided needle positioning in sensory nerve conduction study of the sural nerve

OBJECTIVES: To evaluate the usefulness of ultrasound imaging to improve the positioning of the recording needle for nerve conduction studies (NCS) of the sural nerve. METHODS: Orthodromic NCS of the sural nerve was performed in 44 consecutive patients evaluated for polyneuropathy. Ultrasound-guided needle positioning (USNP) was compared to conventional "blind" needle positioning (BNP), electrically guided needle positioning (EGNP), and to recordings with surface electrodes (SFN). RESULTS: The mean distance between the needle tip and the nerve was 1.1 mm with USNP compared to 5.1 mm with BNP (p<0.0001). The mean amplitude of the sensory nerve action potential (SNAP) was 21 microV with USNP and 11 microV with BNP (p<0.0001). Compared to BNP, nerve-needle distances and SNAP amplitudes did not improve with EGNP. SNAP amplitudes recorded with SFN were significantly smaller than with BNP, EGNP and USNP. CONCLUSION: Ultrasound increases the precision of needle positioning markedly, compared to conventional methods. The amplitude of the recorded SNAP is usually clearly greater using USNP. In addition, USNP is faster, less painful and less dependent on the patient. SIGNIFICANCE: USNP is superior to BNP, EGNP, and SFN in accurate measurement of SNAP amplitude. It has a potential use in the routine near-nerve needle sensory NCS of pure sensory nerves.