Bio-, Magneto- and event-stratigraphy across the K-T boundary

Determining the time and the time structure of rare events in geology can be accomplished by applying three different and independent stratigraphic methods: Biostratigraphy, magneto-stratigraphy and event-stratigraphy. The optimal time resolution of the two former methods is about 1000 years, while by means of event-stratigraphy a resolution of approximately one year can be achieved. For biostratigraphy across the Cretaceous-Tertiary (K-T) boundary micro- and nannofossils have been found best suited. The qualitative and quantitative analyses of minerals and trace elements across the K-T boundary show anomalies on a millimeter scale and permit conclusions regarding the time structure of the K-T event itself. The results of the analyses find a most consistent explanation by the assumption of an extraterrestrial impact. The main portion of the material rain from the atmosphere evidently was deposited within a short time. The long-time components consist of the finest portion of the material rain from the atmosphere and the transported and redeposited fall-out

Density-dependent interactions and structure of charged colloidal dispersions in the weak screening regime

We determine the structure of charge-stabilized colloidal suspensions at low ionic strength over an extended range of particle volume fractions using a combination of light and small angle neutron scattering experiments. The variation of the structure factor with concentration is analyzed within a one-component model of a colloidal suspension. We show that the observed structural behavior corresponds to a non-monotonic density dependence of the colloid effective charge and the mean interparticle interaction energy. Our findings are corroborated by similar observations from primitive model computer simulations of salt-free colloidal suspensions.Comment: Revised version, accepted to Phys. Rev. Let

New insight into cataract formation -- enhanced stability through mutual attraction

Small-angle neutron scattering experiments and molecular dynamics simulations combined with an application of concepts from soft matter physics to complex protein mixtures provide new insight into the stability of eye lens protein mixtures. Exploring this colloid-protein analogy we demonstrate that weak attractions between unlike proteins help to maintain lens transparency in an extremely sensitive and non-monotonic manner. These results not only represent an important step towards a better understanding of protein condensation diseases such as cataract formation, but provide general guidelines for tuning the stability of colloid mixtures, a topic relevant for soft matter physics and industrial applications.Comment: 4 pages, 4 figures. Accepted for publication on Phys. Rev. Let

Dupuytren's disease in bosnia and herzegovina. An epidemiological study

BACKGROUND: It is generally held that Dupuytren's disease is more common in northern than in southern Europe, but there are very few studies from southern European countries. METHODS: We examined the hands of 1207 men and women over the age of 50 years in Bosnia and Herzegovina. RESULTS: The prevalence of Dupuytren's disease was highly age-dependent, ranging from 17% for men between 50–59 years to 60% in the oldest men. The prevalence among women was lower. The great majority only had palmar changes without contracture of the digit. The prevalence was significantly lower among Bosnian Muslim men than among Bosnian Croat and Serbian men and significantly increased among diabetics. No association could be detected between Dupuytren's disease and smoking, alcohol consumption or living in rural or urban areas. CONCLUSION: We conclude that, contrary to previous opinion, Dupuytren's disease is common in Bosnia and Herzegovina

Reversible temperature regulation of electrical and thermal conductivity using liquid–solid phase transitions

Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions

A simple patchy colloid model for the phase behavior of lysozyme dispersions

We propose a minimal model for spherical proteins with aeolotopic pair interactions to describe the equilibrium phase behavior of lysozyme. The repulsive screened Coulomb interactions between the particles are taken into account assuming that the net charges are smeared out homogeneously over the spherical protein surfaces. We incorporate attractive surface patches, with the interactions between patches on different spheres modeled by an attractive Yukawa potential. The parameters entering the attractive Yukawa potential part are determined using information on the experimentally accessed gas-liquid-like critical point. The Helmholtz free energy of the fluid and solid phases is calculated using second-order thermodynamic perturbation theory. Our predictions for the solubility curve are in fair agreement with experimental data. In addition, we present new experimental data for the gas-liquid coexistence curves at various salt concentrations and compare these with our model calculations. In agreement with earlier findings, we observe that the strength and the range of the attractive potential part only weakly depend on the salt content

Açık Erişim ve Akademik Arşiv Politikası

The purpose of this policy is to provide global open access via internet to Özyeğin University’s scientific research results within the framework of open access principles. Open Access to research publications aims to improve the recognition of the university and its researchers and also to increase the number of citation of the publications. It also ensures the rise of the prestige of the university. The content of the academic archive is composed of preprint, postprint or publisher version of the articles, conference materials, master’s theses, PhD dissertations, book chapters and other types of publications. The inputs of the projects supported by fund providers are also included in the academic archive.Bu politikanın amacı Özyeğin Üniversitesi personelinin bilimsel yayınlarının internet aracılığı ile tüm dünyaya ücretsiz olarak açık erişim prensipleri çerçevesinde erişime açık olarak sağlanmasıdır. Araştırma yayınlarının açık erişim yolu ile yayınlanması, hem üniversitenin hem de araştırmacıların tüm dünyada tanınırlığının artmasına ve araştırmaların daha fazla atıf almasına yardımcı olacak; ayrıca üniversitenin saygınlığını geliştirecektir. Kapsam içeriğinde olan yayınlar Özyeğin Üniversitesinin dış dünyaya yaptığı katkılar olan araştırma literatürü, makaleler, konferans bildirileri, yüksek lisans ve doktora tezleri, kitap bölümleri ve diğer yayınların ön baskısı, son baskısı ya da yayıncı sürümüdür. Bununla birlikte araştırma literatürü kapsamında fon sağlayıcı kuruluşlarınca desteklenen proje çıktıları da yer alır

Patterns of peripheral blood B-cell subtypes are associated with treatment response in patients treated with immune checkpoint inhibitors: a prospective longitudinal pan-cancer study

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized systemic anti-tumor treatments across different types of cancer. Nevertheless, predictive biomarkers regarding treatment response are not routinely established yet. Apart from T-lymphocytes, the humoral immunity of B-lymphocytes is studied to a substantially lesser extent in the respective setting. Thus, the aim of this study was to evaluate peripheral blood B-cell subtypes as potential predictors of ICI treatment response. METHODS: Thirty-nine cancer patients receiving ICI therapy were included into this prospective single-center cohort study. All had a first blood draw at the date before treatment initiation and a second at the time of first response evaluation (after 8-12 weeks). Seven different B-cell subtypes were quantified by fluorescence-activated cell sorting (FACS). Disease control- (DCR) and objective response rate (ORR) were co-primary study endpoints. RESULTS: Overall, DCR was 48.7% and ORR was 25.6%, respectively. At baseline, there was no significant association of any B-cell subtype with neither DCR nor ORR. At the first response evaluation, an increase in the frequency of CD21(-) B-cells was a statistically significant negative predictor of response, both regarding DCR (OR=0.05, 95%CI=0.00-0.67, p=0.024) and ORR (OR=0.09, 95%CI=0.01-0.96, p=0.046). An increase of the frequency of switched memory B-cells was significantly associated with reduced odds for DCR (OR=0.06, 95%CI=0.01-0.70, p=0.025). Patients with an increased frequency of naïve B-cells were more likely to benefit from ICI therapy as indicated by an improved DCR (OR=12.31, 95%CI=1.13-134.22, p=0.039). CONCLUSION: In this study, certain B-cell subpopulations were associated with ICI treatment response in various human cancer types