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The Political and Economic Relationship of American-Dutch Colonial Administration in Southeast Asia : A Case Study of the Rivalry between Royal Dutch/Shell and Standard Oil in the Netherlands Indies (1907-1928)
No full textCompetition for control over the exploration, exploitation, distribution and marketing of the world’s oil sources has been a key feature of 20th century history. Competition was usually fierce; oil is a highly sought after commodity and was an essential part to industrialization efforts. In Southeast Asia, in particular in the Dutch Indies in the late 19th and early 20th century, competition for oil was fought between three companies: the oil companies Standard Oil and Royal Dutch, and the transportation company – Shell Transport and Trading Company. The latter two companies would merge into one of the biggest oil companies in the world, and become Royal Dutch Shell. Competition between Standard Oil and Royal Dutch Shell would eventually involve not only the two companies but also the governments of the two countries they were headquartered in: that is the United States of America and The Netherlands. Washington and The Hague became involved once it was clear that the Dutch were attempting to prevent Standard Oil from operating in the Dutch Indies by refusing to grant oil concessions to the American company.
The United States Government was concerned about the energy crisis at the end of World War I, and so supported American companies’ oil efforts, in particular Standard Oil of New Jersey, to obtain oil concessions abroad, including in the Dutch East Indies. At the same time, the Dutch sought to support the Dutch oil companies’ in their quest to dominate the oil industry in the Dutch Indies, and so issued the Dutch Indies Mining Act, also known as the Indische Mijnwet. The desire to expand their business interests into the Dutch Indies, and the Dutch’s attempts to restrict an influx of foreign capital into the Dutch Indies seem to indicate a conflict between American liberalism or free market, and Dutch protectionism.
The United States conducted intense efforts through the State Department and American Consuls in The Hague and Batavia to persuade the Dutch government to provide equal opportunities for American oil companies who wanted to undertake oil exploration in the Dutch Indies. However, the political and economic independence of the Dutch from Washington made the United States’ diplomatic efforts difficult, and largely unsuccessful. The internal situation of the Dutch colonial government in the Dutch Indies, especially with the change in Governor-General in 1926,and the Dutch colonial government’s financial difficulties and lack of capital to fully exploit all the oil sources in the Dutch Indies, were the primary factors that eventually led the Dutch government to grant oil concessions to Standard Oil, via NKPM, one of their subsidiaries that operated in the Dutch Indies
From Ethnomedicine to Application: Biological Activities and Cytotoxicity of Leaf Extracts from Plants of the Genus Rhododendron
No full textThe evolution of bacterial resistance to current antibiotics is one of the biggest threats to human health. There is an increasing interest to identify novel antimicrobial compounds from various natural sources. Plants-derived compounds are used as ingredients in traditional treatment of numerous human disorders including infectious diseases caused by pathogenic microorganisms. In planta, secondary metabolites like the polyphenols are known to act as potent antimicrobial agents against several plant pathogens. Plants of the genus Rhododendron are typically used in a range of ethno-medical applications. There are more than 1,000 Rhododendron species growing/spreading/distributed particularly in the Northern hemisphere. The City of Bremen harbors the Rhododendron-Park in which approximately 600 different species of Rhododendron and hybrids are grown. This enables research with about two thirds of all known Rhododendron species.
The aim of this study is to identify novel compounds from the secondary metabolite pool synthesized by Rhododendron that can be used as antimicrobial treatments of human diseases/maladies in form of ectopic application or as orally administered drugs. Therefore, leaf extracts of a total of 120 different Rhododendron species were tested using the agar diffusion assay towards twenty-six bacterial species representing different taxonomic clades of non-pathogenic strains Gram-positive and Gram-negative bacteria. The possible cytotoxic effects of the most promising, antimicrobial bioactive extracts from Rhododendron species were assessed in a concentration-dependent manner using epidermal keratinocytes of the skin and epithelial cells of the intestinal mucosa, respectively, as target cell systems.
The leaf extracts of 17 Rhododendron species exhibited significant growth-inhibiting activities against Gram-positive bacteria. In contrast, only very few of the leaf extracts affected the growth of Gram-negative bacteria. All leaf extracts with antimicrobial bioactivity were extracted from representatives of the subgenus Rhododendron, with 15 from the sub-section Rhododendron and two belonging to the section Pogonanthum. Six Rhododendron species out of the 17 species showed the lowest minimum inhibitory concentration with 50 µg leaf extract powder per mL solvent. Equally low and moderate concentrations (50 µg/ml) of leaf extracts from three of these plant species were non-toxic towards both mammalian cell lines, i.e. HaCaT keratinocytes and IEC6 enterocytes. However, higher doses such as 500 µg/mL of Rhododendron leaf extracts were potent in negatively affecting both, keratinocytes and, particularly, the intestine epithelial cells.
We conclude that bioactive compounds with high antimicrobial activities can be extracted from the leaves of Rhododendron species mainly belonging to the subgenus Rhododendron, and that they acted mostly against Gram-positive organisms. The leaf extracts from R. minus, R. ferrugineum, and R. racemosum applied at a concentration of 50 µg/ml proved safe to be used in 24-h-incubations of monolayer cultures of both, HaCaT keratinocytes and IEC6 intestine epithelial cells. In contrast, high doses of most leaf extracts induced apoptosis evidenced by a significant increase in the levels of active caspase-3 in IEC6 intestine epithelial cells. Finally, keratinocytes proved more resistant than intestine epithelial cells against cytotoxicity exerted by leaf extracts of a large variety of Rhododendron species
Priorisierung in der Onkologie. Einstellungen von verschiedenen Interessengruppen zur Verteilung onkologischer Leistungen: Eine Mixed Methods-Studie
No full textTrotz des enormen Fortschritts in Bezug auf Heilung in der Onkologie und die dadurch erhöhte Lebenserwartung, verbessern Behandlungen den Gesundheitszustand häufig nur geringfügig oder bringen starke Nebenwirkungen mit sich. Die vorliegende Studie untersucht die Präferenzen verschiedener Stakeholdergruppen sowie ihre Kriterien bezüglich der Allokation medizinischer Ressourcen.
Ein „Exploratory Sequential-Design” wurde verwendet, um diese Präferenzen vertieft zu untersuchen. In einem ersten Schritt wurden 16 qualitative, halbstrukturierte Interviews mit verschiedenen Stakeholdern durchgeführt (acht Krebspatienten, drei Onkologen, drei Pflegekräfte, einen Verwaltungsmitarbeiter, einen Mitarbeiter der GKV) und anschließend einer Inhaltsanalyse unterzogen. Priorisiert wurde insbesondere die medizinische Versorgung, Betreuung durch das Personal sowie das Wohlbefinden der Patienten. Weiterhin wurden Einstellungen und Präferenzen über bestehende und neue Kriterien diskutiert (z. B. Lebensqualität, Aufwand für den Patienten, Alter).
Aufbauend auf den Ergebnissen, soll nun die vorliegende Studie herausfinden, ob die Präferenzen einer größeren, repräsentativeren Befragtengruppe diesen Resultaten entsprechen und ob die zuvor aufgedeckten Kriterien für eine Priorisierung akzeptiert oder abgelehnt werden. Hierfür wurde ein Fragebogen mit standardisierten Fragen und Szenarien mit vorgegebenen Antwortoptionen erstellt. 143 Interviews wurden mit Krebspatienten, Angehörigen und Mitarbeitern (Ärzte, Pflegekräfte, Verwaltungsmitarbeiter, Therapeuten) des Klinikums Bremen Mitte durchgeführt. Soziodemographische Variablen wurden sowohl für Kontingenztafelanalysen, für einen Kruskal-Wallis- und Mann-Whitney-Test als auch für Regressionsmodelle und partielle Korrelationen herangezogen, um spezifische Hypothesen zu testen und um die Variabilität der Daten zu erklären. Die medizinische Versorgung und Kriterien bezogen auf den therapeutischen Nutzen (z. B. Heilung, Lebensqualität, Lebensverlängerung) stellten sich als die wichtigsten Faktoren heraus. Die Studie fand außerdem zahlreiche Unterschiede zwischen den Einstellungen unterschiedlicher Stakeholder, insbesondere zwischen Patienten und Mitarbeiter.Despite the enormous progress in medical cures in oncology leading to an increasing life expectancy, some treatments often improve the health status only marginally or cause strong adverse effects. This study examines preferences of different stakeholder groups with respect to their criteria concerning the allocation of medical resources.
An Exploratory Sequential-Design was used to investigate these preferences extensively. In a first step 16 qualitative semi-structured interviews with different stakeholder groups (eight cancer patients, three oncologists, three nurses, one administrative officer, one representative of health insurance companies) were conducted and subjected to content analysis. Priorities were particularly set in medical supply, support by staff and in aspects concerning the well-being of patients. Moreover, attitudes and preferences about existing und new criteria were discussed (e.g. quality of life, patients’ commitment, age).
Building on these results, the aim of the present study is to find out whether preferences of a larger, more representative group are similar and whether criteria for prioritizing patients and services mentioned in the qualitative interviews are accepted or rejected. A questionnaire with standardized questions and scenarios with predefined response options was conducted. 143 interviews were carried out with cancer patients, relatives and different staff members including medical practitioners, nurses and administrative officers of a hospital in Bremen, Germany. Sociodemographic variables were not only elicited to serve as variables in contingency analyses and in the Kruskal-Wallis- and Mann-Whitney-Test, but also as covariates in regression models and partial correlations to test specific hypotheses and to account for the variability in the data. Aspects concerning medical supply and criteria concerning therapeutic benefit (e.g. cure, quality of life, life extension) emerged as the most important factors. The study also found numerous differences in the attitudes of the different stakeholders involved, especially between patients and staff members
Driving Forces for Supramolecular Encapsulation in Water
No full textFor explaining association phenomena in aqueous solution, whether between a macrocyclic host and an encapsulated guest or between a biological receptor and its corresponding ligand, one should understand the driving forces. The present doctoral thesis describes the supramolecular chemistry of different host-guest systems. Besides contributing to the fundamental understanding of the hydrophobic, fluorophilic, and chaotropic effect, the results have implications for a wide range of applications: supramolecular sensors, hydrocarbon and perfluorinated molecules separation and purification, and the efficient removal of such guest molecules from aqueous solution
Work Biographies as Facilitators of Cognitive and Brain Development: A Lifespan Perspective on Occupational Health
No full textIn Germany as well as in most industrialized countries of the Western hemisphere, the workforce is constantly ‘aging’. Increasing age, however, is associated with a number of health risks. Cognitive decline may be a particular challenge to health at work. Long-term exposure to low mental stimulation at work has detrimental effects on brain and cognition. Low job complexity has repeatedly been associated with lower levels of cognitive functioning and with a higher risk of cognitive impairment and dementia. But good cognitive health is a necessary prerequisite to preserve well-being, work ability, and productivity. However, research has not yet found an effective way how to counteract these effects. This dissertation set out to fill this gap. Therefore, three studies were conducted: a conceptual literature review which systematized the available evidence on 'in vivo' mental stimulation as well as two experimental studies that investigated the effect of multiple work-task changes (WTC) on the cognitive functioning and brain anatomy of long-term industrial production workers. The findings reveal that (a) besides complexity, active learning and recurrent novelty can serve as valuable facilitators of positive plasticity in the cognitive system, (b) industrial production workers who underwent multiple WTC over 17 years showed higher levels of cognitive functioning, and displayed (c) more gray matter volume in hypothesized areas than a matched control group with 0 or 1 WTC. With this, the current dissertation extends the available evidence on the critical contextual features that foster cognitive plasticity; suggests recurrent exposure to WTC as strategic health management instrument to counteract cognitive decline; underlines the importance of cognitive health and cognitive aging as vital but neglected fields of occupational health psychology; and emphasizes the need for a lifespan developmental perspective on occupational health management
Sea-Ice Thickness derived from CryoSat-2: Validation and Uncertainties
No full textSatellite altimetric measurements by the 2010 launched ESA satellite CryoSat-2 are capable of obtaining the thickness distribution of marine ice fields. With its on-board Ku- band radar altimeter we retrieve the sea-ice freeboard, the height of the ice surface above the actual sea level, and finally the thickness by assuming hydrostatic equilibrium. In this thesis I estimate CryoSat-2 Arctic sea-ice freeboard and thickness and their corresponding uncertainties. In particular I focus on the impact of different retracking algorithms that are used to retrieve CryoSat-2 range estimates. In recent studies, snow is considered as transparent for Ku-band frequencies, although a possible bias is acknowledged. Therefore, another goal of this work is to investigate the impact of snow coverage since it may affect the backscatter of the radar signal due to its physical properties. Likewise we use validation measurements from airborne laser altimetry, ice-mass balance buoys and in-situ drilling to evaluate CryoSat-2 sea-ice retrievals on both hemispheres. The findings show that random uncertainties are dominated by speckle noise and the density of leads along the flight track of the satellite. On the other hand, systematic uncertainties result from the choice of the retracking algorithm and in particular the echo power threshold which is used to determine the main scattering horizon. This bias is accompanied by systematic uncertainties due to scattering within the snow layer in conjunction with surface roughness effects. Moreover, we find observational evidence that CryoSat-2 freeboard increase correlates with snow accumulation events over Arctic multiyear ice, regardless of the used retracking algorithm. Such biases may lead to overestimated sea-ice thickness, as observed in autumn 2013 north of Canada. However, comparisons with airborne laser altimetry data, in-situ drilling measurements and other remote sensing sensors show that the freeboard and thickness retrieval represent the geographical distribution of sea-ice types. In the future, a data fusion with thickness retrievals from other past, present and future satellite sensors has the capability to reduce the uncertainty level and enables the prediction of long-term trends in sea-ice volume
Potential-Induced Degradation : A Multi-Level Problem
No full textPotential-induced Degradation (PID) is one of the most severe reliability problems for the Photovoltaic industry in the recent years.
As a first step towards understanding PID, in a collaboration with SCHOTT Solar, a climate model was developed - both to map and quantify the dependence of the effect on environmental factors like temperature and relative humidity, and to find a method to screen materials for susceptibility to PID. Such investigations allow for the lifespan of a standard PV module to be predicted depending on the environmental conditions, installation properties and the building components of the module. Additionally, the thermal regeneration under variety of conditions was studied, both to mitigate the effect and collect more information for model building. Furthermore, the leakage current behavior and its correlation to PID was studied. As an alternative, a two-step lifetime warranty test for PID was designed and developed.
The second part of this thesis, together with SolarWorld Innovations, focused on investigating the root cause of PID. Three root-cause hypotheses were developed and tested – the Li Hypothesis, the Inversion Layer Hypothesis and the other hypothesis involving the decoration of stacking faults with sodium. These theses were critically evaluated, partially refuted and eventually extended by the proposition that those stacking faults (and other crystal defects) have process-induced nature. One critical approach to limit PID on cell level was studied in further depth – the emitter oxidation. During the course of this work, PID was observed to be a rather polyvalent defect mechanism – it was made obvious that more defect mechanisms contribute to PID. The process-induced crystal defects during high-temperature processing (as well as contaminants in the silicon) was identified as one of the most important mechanisms. It could explain a number of the complex phenomena and non-uniformities on cells and module level related to PID
Mobility of High-Technology Metals in Earth’s Surface Environment : A Study on Siderophore-Promoted Mobilization and Implications for the Extractive Hydrometallurgy of some Critical Metals
No full textThis study addresses the influence of siderophores on the geochemical behavior of critical metals in rocks, ores and aqueous solutions. Rare earth elements and Y, the platinum group elements as well as other high field strength elements such as Zr, Hf, Th and U are presently referred to as high technology metals with many of them classified as critical metals. These critical metals are facing a distinct supply risk due to high production concentration and/or processing issues but are, however, essential for the development of state-of-the-art industries. Today’s industries rely on a steady supply of these metals for their economic development and the industry’s demand as well as the linked anthropogenic input of these metals will likely increase significantly in the near future.
Siderophores are produced by a variety of microbes and plants in Fe-deficient environments to solubilize sparingly soluble Fe. However, siderophores also complex a range of other polyvalent metal ions. This study elucidates the mechanisms and the geochemical implications behind leaching with the hydroxamate siderophore desferrioxamine B (DFOB) and focuses on the siderophore-promoted mobility of ‘immobile’ high field strength elements. The second goal of this thesis was to elaborate to what extent siderophores can be used for processing and extraction of high technology metals from mineralogically complex ores like oxidized Platinum Group Element (PGE) ores or deep-sea ferromanganese nodules and crusts.
Leaching of rocks and particle-rich aqueous solutions with siderophores leads to a significant mobilization of the ‘immobile’ high field strength elements like rare earth elements, Zr, Hf, Th and U and to distinct features in REY patterns. Bulk-rock normalized REY patterns of leaching solutions with DFOB showed a very distinct positive Ce anomaly and a depletion of La and other light REY relative to the middle REY, with a concave downward pattern between La and Sm. The “siderophore redox pump” that is first described in this thesis leads to a preferential enrichment of redox-sensitive Ce and U relative to redox-insensitive dissolved LREY and Th during siderophore leaching due to changes in the redox equilibrium and preferential complexation of oxidized species by DFOB. The observed fractionation patterns and decoupling of Ce and U by siderophore-induced oxidation might be helpful in constraining the presence of siderophores or chemically similar metal-specific organic chelating agents present during weathering and might be used as a bio-proxy for paleoenvironmental research.
Furthermore, a leaching process was developed and is presented in this thesis that uses siderophores for the extraction of Pt and Pd from oxidized (weathered) Platinum-Group Element (PGE) ores of the Great Dyke, Zimbabwe. Current mining operations focus on the recovery of PGE from pristine and unweathered ore material from the Main Sulfide Zone (MSZ). The oxidized PGE ores are currently not mined, because recoveries using conventional processing techniques render this uneconomic. The data presented in this study indicates chemical extraction of Pt and Pd at alkaline conditions as (Pt,Pd)HDFOB and/or (Pt,Pd)H2DFOB+ complexes. Up to 80% Pt were mobilized using the developed leaching process. Siderophores also represent viable reagents for the hydrometallurgical extraction of high technology metals from ferromanganese nodules and crusts. Deep-sea ferromanganese deposits contain a wide range of high technology metals and are considered an important future resource, but extraction techniques, especially with respect to high technology metals, are still not established. The data on leaching of ferromanganese nodules and crusts presented in this thesis showed that the high technology metals Li, Mo, Zr, Hf, Nb and Ta are significantly extracted using siderophores, whilst base metals are not mobilized to large extents.
This study highlights the importance of siderophores for the mobility and fractionation of certain high technology metals in the environment. The data presented in this study shows that siderophores like desferrioxamine B not only enhance the solubility and mobility of Fe(III), but also strongly enhance the mobility of ‚immobile‘ high field strength and highly siderophile elements such as the rare earth elements, Zr, Hf, Th, U and Pt and Pd. Additionally, siderophores or similar specific metal-binding organic ligands have a promising potential in future processing technologies of oxide deposits like those investigated in this study
Antibiotic permeation through membrane proteins
No full textThe outer membrane of bacteria forms an effective barrier; hence hydrophilic antibiotics are known to use porin pathway to reach the target inside the bacterium. With the overuse of antibiotics in clinics, bacteria have evolved to become resistant and one of the ways to do so is to reduce the intake of antibiotics. Increasing antibiotic resistance is recognized as a major public health threat. Antimicrobial drug discovery faces unique challenges, primarily to produce compounds which have sufficient permeation across outer membrane of bacteria. In this regard it becomes indispensable to measure the translocation rate and understand the molecular mechanism of antibiotic transport through porin channel.
In this thesis we investigate two aspects: one to study antibiotic transport across clinically relevant porins and understand their contribution in antibiotic resistance; Second, to elucidate the translocation mechanism of the relevant antibiotics across porins from Gram-negative and Gram-positive bacteria.
In the first part, we studied antibiotic translocation across, major porin from pathogen Providencia stuartii and porin mutants from Escherichia coli clinical strain. A multidisciplinary approach, including single channel electrophysiology, liposome permeation assay, microbiological assays and molecular dynamic simulations, provided an understanding of permeability from macro scale to atomic scale. In the second part of the thesis, we mainly investigate the interaction of β-lactam and fluoroquinolone class of antibiotics with porins from E. coli and Nocardia farcinica at a single molecule level. An assay based on fluorescence detection in vesicles in microfluidic chambers is employed to obtain translocation rate of fluoroquinolone antibiotic across porins in a quantitative manner. Modulating parameters like pH significantly changes the kinetics of norfloxacin through OmpF in electrophysiology. Voltage dependent transport of antibiotic norfloxacin through single OmpF is reported and we discuss different contributions involved in the translocation of antibiotic through channel.
We conclude that altered permeability across porins contributes to reduced susceptibility. By varying different parameters, like effect of point mutations in antibiotic translocation through channels or varying the charge state of antibiotic, we decipher the rate limiting interactions which might be useful for rational drug designing
Differential Effects of Physical Activity on Older Adults' Brain Structure
No full textIn late adulthood, cognitive performance declines and brain structure deteriorates. However, research indicates that both may be diminished by certain lifestyle factors. Physical activity, especially cardiovascular activity, has been revealed as such a lifestyle factor, which benefits both cognitive performance and its neural correlates. This dissertation examined in four empirical studies how coordinative activity in healthy older adults is associated with changes or individual differences in cognitive functioning and brain structure and whether effects of cardiovascular and coordinative activity differ from each other.
Results indicate that motor fitness was positively related to volume of the hippocampus, basal ganglia and anterior cingulate gyrus and white matter microstructure in the medial frontal gyrus and the anterior commissure. Coordination training was shown to increase volume of the hippocampus, caudate and globus pallidus. Additionally, coordinative activity was positively associated with executive control and perceptual speed. Less evidence was found for beneficial effects of cardiovascular activity. White matter microstructure in frontal brain regions was positively related to cardiovascular fitness and cardiovascular training increased hippocampal volume. Senior dancing activity, however, did not benefit cognitive functioning and its effects on the brain were small in size and limited to frontal regions only. Thus, coordinative activity had stronger effects on brain structure than cardiovascular activity. The relationship between volumetric changes in the brain following physical activity and cognitive improvements in older adults remains largely diffuse.
Findings of the current dissertation have practical implications for the design of physical activity interventions for older adults and highlight the need for future intervention studies exploring the effects of coordinative activity on cognitive performance and brain structure and function