Disruption of diphenylalanine assembly by a Boc-modified variant

Peptide-based biomaterials are key to the future of diagnostics and therapy, promoting applications such as tissue scaffolds and drug delivery vehicles. To realise the full potential of the peptide systems, control and optimisation of material properties are essential. Here we invesigated the co-assembly of the minimal amyloid motif peptide, diphenylalanine (FF), and its tert-butoxycarbonyl (Boc)-modified derivative. Using Atomic Force Microscopy, we demonstrated that the co-assembled fibers are less rigid and show a curvier morphology. We propose that the Boc-modification of FF disrupts the hydrogen bond packing of adjacent N-termini, as supported by Fourier transform infrared and fluorescence spectroscopic data. Such rationally modified co-assemblies offer chemical functionality for after-assembly modification and controllable surface properties for tissue engineering scaffolds, along with tunable morphological vs. mechanical properties

Real-time measurement of the intracellular pH of yeast cells during glucose metabolism using ratiometric fluorescent nanosensors

Intracellular pH is a key parameter that influences many biochemical and metabolic pathways that can also be used as an indirect marker to monitor metabolic and intracellular processes. Herein, we utilise ratiometric fluorescent pH-sensitive nanosensors with an extended dynamic pH range to measure the intracellular pH of yeast (Saccharomyces cerevisiae) during glucose metabolism in real-time. Ratiometric fluorescent pH-sensitive nanosensors consisting of a polyacrylamide nanoparticle matrix covalently linked to two pH-sensitive fluorophores, Oregon green (OG) and 5(6)carboxyfluorescein (FAM), and a reference pH-insensitive fluorophore, 5(6)carboxytetramethylrhodamine (TAMRA), were synthesised. Nanosensors were functionalised with acrylamidopropyltrimethyl ammonium hydrochloride (ACTA) to confer a positive charge to the nanoparticle surfaces that facilitated nanosensor delivery to yeast cells, negating the need to use stress inducing techniques. The results showed that under glucose-starved conditions the intracellular pH of yeast population (n ≈ 200) was 4.67 ± 0.15. Upon addition of D-(+)-glucose (10 mM), this pH value decreased to pH 3.86 ± 0.13 over a period of 10 minutes followed by a gradual rise to a maximal pH of 5.21 ± 0.26, 25 minutes after glucose addition. 45 minutes after the addition of glucose, the intracellular pH of yeast cells returned to that of the glucose starved conditions. This study advances our understanding of the interplay between glucose metabolism and pH regulation in yeast cells, and indicates that the intracellular pH homestasis in yeast is highly regulated and demonstrates the utility of nanosensors for real-time intracellular pH measurements

Investigation of small-cell lung cancer epidemiology in Sweden and analysis of clinical and tumor specific prognostic biomarkers

Small-cell lung cancer (SCLC) accounts for approximately 13% of all newly diagnosed lung cancer (LC) cases. This disease is correlated with heavy smoking. It is characterized by a rapid doubling time combined with a propensity to metastasize quickly and by neuroendocrine differentiation. In patients with locally advanced disease, the standard of care is concurrent radiation and platinum-doublet chemotherapy (PDCT). Patients with stage IV disease have also until recently been treated with PDCT. Even though a majority of SCLC cases initially responds to PDCT, almost all patients inevitably relapse. This thesis aims to deepen the knowledge of SCLC. Paper I was a population-based study, where we aimed to investigate the possible association between educational levels and overall death of Swedish SCLC patients. The patient population consisted of 4256 subjects. The key findings showed that educational level is an independent prognostic factor in Swedish men diagnosed with SCLC and among patients with Limited disease. In paper II, we performed a validation of the 8th TNM staging system on 706 SCLC cases and compared the system´s prognostic performance to the 6th and 7th TNM editions as well as to the older two-stage system that segmented patients as either having Limited Disease (LD) or Extensive Disease (ED). The study provided additional information supporting the robustness of the 8th TNM edition in prognostically categorizing SCLC and confirms its usefulness in clinical practice. In paper III, we conducted a real-world study on 545 consecutive cases during an eight-year period. The aim was to understand in depth the treatment patterns of SCLC patients from Karolinska University Hospital. Another goal was to examine the outcome of SCLC patients upon re-challenge with PDCT. The survival outcomes for LD and ED SCLC patients were poor, correlating with previous studies. The results also showed that SCLC patients with sensitive relapse after first line PDCT may benefit from re-challenge. In paper IV, the expression of multiple biomarkers, including Notch1, Hes1, Ascl1, and DLL3, were analysed in a selected cohort of 46 SCLC patients. The study, in part, focused on how the expression patterns differed based on patients’ resistance or sensitivity to PDCT. We evaluated the prevalence of expression of these four biomarkers in human samples using biopsies and studied the potential association with survival and benefit from 1st line PDCT. The study showed that Notch1 seems to be an independent prognostic factor in SCLC. Furthermore, a negative association between Notch1 and Ascl1 expression was observed. In summary, this thesis expands on the understanding of SCLC by analysing epidemiological trends, the impact of socioeconomic status, changes to classifying patients, and possible prognostic biomarkers

Are Health Problems in Adulthood linked to our Experiences in the Womb? An Epigenetic Approach

The origins of adult disease have been a prime topic for research, as deciphering causes can lead to strategies for preventions and cures. There has been recent intrigue focused on the environment in the womb. Records from England and Wales in 1911 show that those who suffered from cardiovascular disease were geographically correlated with regions high in infant mortality in the past, seventy years before the study. When looking into the cause of the neonatal death rates, low birth weight, poor maternal health, and high maternal death rates during childbirth were clearly associated. Barker inferred that there is much happening in the intrauterine environment that ultimately affects our quality of life. This research helps support the concept that rather than looking at childhood adversity and socioeconomic circumstances to help explain adult disease, we might need to reach further back (Barker,1990). Through epigenetic mechanisms, alterations to the physical expression of our DNA can take place without changing the sequences of the actual DNA. Epigenetics is what is responsible during fetal development for the differentiation of stem cells to specific cells by adding or subtracting methyl groups to silence or activate particular genes. When an egg and sperm unite all previous methylation patterns are stripped from the newly formed diploid. However, by the time it becomes a blastocyst, new patterns have already formed. It is during this crucial stage of development that new patterns and changes to our epigenome our founded and passed down (Powledge, 2009). The purpose of this paper is to determine if chronic health issues in adulthood have their roots in the environment and changes experienced by the fetus in the womb. Environmental exposures like nutrition, stress, and toxicants are evaluated and tested for their potential hand in setting the course for adult disease. Many studies show correlation between malnutrition and the development of metabolic diseases like obesity, type II diabetes, and even hypertension. Likewise, stress during gestation has been linked to anxiety, depression, and posttraumatic stress disorder (PTSD) in offspring. Toxicants like bisphenol-A are the likely culprit for genetically expressed abnormalities that range from cancers of the reproductive system to attention/deficit hyperactive disorder (ADHD) in exposed offspring. The “how” and the “why” are explored in this paper. If we can better understand the origins of adult disease then we are better equipped to defend our future generations against it. Furthermore, the notion that our DNA is not at fault for these outcomes, but rather epigenetic adjustments written on top of our DNA, provides hope that just as easily as it can be added on, we can take it off (Powledge, 2009)

Merit, Tenure, and Bureaucratic Behavior: Evidence From a Conjoint Experiment in the Dominican Republic

Bureaucratic behavior in developing countries remains poorly understood. Why do some public servants – yet not others – work hard to deliver public services, misuse state resources, and/or participate in electoral mobilization? A classic answer comes from Weber: bureaucratic structures shift behavior towards integrity, neutrality, and commitment to public service. Our paper conducts the first survey experimental test of the effects of bureaucratic structures. It does so through a conjoint experiment with public servants in the Dominican Republic. Looking at merit examinations and job stability, we find that Weber was right – but only partially. Recruitment by examination curbs corruption and political services by bureaucrats, while enhancing work motivation. Job stability, by contrast, only decreases political services: tenured bureaucrats are less likely to participate in electoral mobilization. Examinations thus enhance the quality of bureaucracy (motivation and lower corruption) and democracy (electoral competition); job stability only enhances the quality of democracy

Measuring the capability to raise revenue process and output dimensions and their application to the Zambia revenue authority

The worldwide diffusion of the good governance agenda and new public management has triggered a renewed focus on state capability and, more specifically, on the capability to raise revenue in developing countries. However, the analytical tools for a comprehensive understanding of the capability to raise revenue remain underdeveloped. This article aims at filling this gap and presents a model consisting of the three process dimensions ‘information collection and processing’, ‘merit orientation’ and ‘administrative accountability’. ‘Revenue performance’ constitutes the fourth capability dimension which assesses tax administration’s output. This model is applied to the case of the Zambia Revenue Authority. The dimensions prove to be valuable not only for assessing the how much but also the how of collecting taxes. They can be a useful tool for future comparative analyses of tax administrations’ capabilities in developing countries.Die weltweite Verbreitung der Good-Governance- und New-Public-Management-Konzepte hat zu einer zunehmenden Konzentration auf staatliche Leistungsfähigkeit und, im Besonderen, auf die Leistungsfähigkeit der Steuererhebung in Entwicklungsländern geführt. Allerdings bleiben die analytischen Werkzeuge für ein umfassendes Verständnis von Leistungsfähigkeit unterentwickelt. Dieser Artikel stellt hierfür ein Modell vor, das die drei Prozess-Dimensionen „Sammeln und Verarbeiten von Informationen“, „Leistungsorientierung der Mitarbeiter“ und „Verantwortlichkeit der Verwaltung“ beinhaltet. „Einnahmeperformanz“ ist die vierte Dimension und erfasst den Output der Steuerverwaltung. Das mehrdimensionale Modell wird für die Analyse der Leistungsfähigkeit der Steuerbehörde Zambias (Zambia Revenue Authority) genutzt. Es erweist sich nicht nur für die Untersuchung des Wieviel, sondern auch des Wie des Erhebens von Steuern als wertvoll. Die vier Dimensionen können in Zukunft zur umfassenden und vergleichenden Analyse der Leistungsfähigkeit verschiedener Steuerverwaltungen in Entwicklungsländern genutzt werden