183 research outputs found
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
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
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
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
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
Synthesis and characterization of novel functional electrosterically stabilized colloidal particles prepared by emulsion polymerization using a strongly ionized amphiphilic diblock copolymer
Amphiphilic diblock copolymers such as poly(styrene)-block-poly(styrene sulfonate) (PS-b-PSS) (Matsuoka, H.; Maeda, S.; Kaewsaiha, P.; Matsumoto, K. Langmuir 2004, 20, 7412), belong to a class of new polymeric surfactants that ionize strongly in aqueous media. We investigated their self-assembly behavior in aqueous solutions and used them as an emulsifier to prepare electrosterically stabilized colloidal particles of different diameters between 70 to 400 nm. We determined the size, size polydispersity, effective charge, total dissociable charge, structural ordering, and phase behavior using light scattering, transmission electron microscopy (TEM), small-angle neutron scattering (SANS), and potentiometric titration. These experiments clearly demonstrated that all of the synthesized particles were nearly monodisperse (polydispersity index ≤ 6%). The results of DLS and TEM clearly suggested the existence of hairy particles. The form factors obtained by SANS were well described by a polydisperse sphere model. The estimated total number of dissociable charges per particle was found to be larger than 10⁴e, whereas the effective charges per particle were found to be around 1000e. This significant difference suggested the confinement of charges inside the corona regions of the polyelectrolyte brush shell. Finally, these monodisperse particles were found to self-assemble into 3D ordered colloidal crystalline arrays at a low volume fraction (= 0.00074) that diffract light in the visible region
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
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