The organization of 2,3-iron-naphthalocyanine molecules on substrate as revealed by scanning tunneling microscopy

Surface morphology of thin molecular layer of 2,3-Iron-naphthalocyanine (2,3 FeNPc) was studied by scanning tunneling microscopy (STM) at the ambient conditions. Organic layer with thickness of 40 nm was vapour phase deposited on amorphous carbon substrate. The STM images have revealed the pecularities of surface molecular organization from large range (hundreds of nm) down to atomic scale. Arrays of locally ordered linear stuctures have been distinguished as the main morphological features of the examined surface. At several places the well-ordered STM patterns have been distinguished at the atomic scale. They can be described as stacks of periodicity approximatelly 0.4 nm in a row and 1.5 nm between stacks. These results can be explained by arrangement of 2,3-FeNPh molecules in stacks with a main plane being perpendicular to the substrate surface

Atomic force microscopy of gel-drawn ultrahigh-molecular-weight polyethylene

Gel-drawn ultrahigh molecular weight polyethylene was studied by atomic force microscopy (AFM). Three-dimensional surface profiles were recorded for tapes drawn to different extents. AFM images allowed the discrimination of different well-defined levels of the fibrillar morphology: (i) bundles of microfibrils with a diameter between 4 and 7 μm strongly depending on the elongation; (ii) microfibrils with a diameter between 0.2 and 1.2 nm which also decreased with increasing draw ratio; (iii) nanofibrils which form the elementary fibrillar building blocks; and (iv) regular chain patterns on the molecular level which correspond to the crystalline packing of polyethylene chains at the surface of the nanofibrils. The nanofibrils were formed during the initial conversion of lamellae to fibrillar crystallites and did not change considerably in diameter up to draw ratios of λ = 70

Organic–inorganic interfaces and spiral growth in nacre

Nacre, the crown jewel of natural materials, has been extensively studied owing to its remarkable physical properties for over 160 years. Yet, the precise structural features governing its extraordinary strength and its growth mechanism remain elusive. In this paper, we present a series of observations pertaining to the red abalone (Haliotis rufescens) shell's organic–inorganic interface, organic interlayer morphology and properties, large-area crystal domain orientations and nacre growth. In particular, we describe unique lateral nano-growths and paired screw dislocations in the aragonite layers, and demonstrate that the organic material sandwiched between aragonite platelets consists of multiple organic layers of varying nano-mechanical resilience. Based on these novel observations and analysis, we propose a spiral growth model that accounts for both [001] vertical propagation via helices that surround numerous screw dislocation cores and simultaneous 〈010〉 lateral growth of aragonite sheet structure. These new findings may aid in creating novel organic–inorganic micro/nano composites through synthetic or biomineralization pathways

Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments

Polyurethane cationomers were synthesised in the reaction of 4,4’-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. 1H, 13C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on 1H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss–Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m2. That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions

ЛУЧЕВАЯ ДИАГНОСТИКА САНКТ-ПЕТЕРБУРГА-2014

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АВТОМАТИЧЕСКАЯ СЕГМЕНТАЦИЯ ОЧАГОВ В БЕЛОМ ВЕЩЕСТВЕ ГОЛОВНОГО МОЗГА

Quantitative characterization of brain lesions may not be only a diagnostic criteria, but also the parameter for dynamic evaluation of various CNS diseases progression. Manual segmentation is the most accurate method of measuring lesions volume, but this method is time- and labor-intensive. There are different methods of automatic lesions segmentation that use different algorithms and have varied accuracy of the results. In this paper we compare two fundamentally different approaches to the automatic lesions segmentation basis on the MRI images and evaluate the possibility of using these methods as an alternative to manual segmentation.Количественная характеристика очагового поражения головного мозга может быть не только диагностическим критерием, но и параметром, позволяющим оценивать динамику развития различных заболеваний центральной нервной системы. Мануальная сегментация является наиболее точным методом измерения общего объема очагов, однако этот метод является время- и трудозатратным. Существуют различные методы автоматической сегментации очагов, которые различаются как используемыми алгоритмами, так и точностью получаемых результатов. В данной работе сравнивается два принципиально разных подхода к автоматической сегментации очагов на основе МРТ-изображений и оценивается возможность использования их в качестве альтернативы мануальному методу

УПРАВЛЕНИЕ ПОТОКАМИ ПАЦИЕНТОВ. РАБОТА С НАПРАВЛЕНИЯМИ ОБЯЗАТЕЛЬНОГО МЕДИЦИНСКОГО СТРАХОВАНИЯ

The article is devoted to the basic principles of interaction as a tool to improve the efficiency of adverse communication between medical facilities for the organization of streams of patients on MRI and CT of the compulsory health insurance.Статья посвящена основным принципам взаимодействия между медицинскими учреждениями как инструменту повышения эффективности коммуникации для организации потоков пациентов на МРТ- и КТ-исследования в рамках системы ОМ

Polymer Networks Produced by Marine Diatoms in the Northern Adriatic Sea

Using high resolution molecular technique of atomic force microscopy, we address the extracellular polymer production of Adriatic diatom Cylindrotheca closterium analyzed at the single cell level and the supramolecular organization of gel phase isolated from the Northern Adriatic macroaggregates. Our results revealed that extracellular polysaccharides freshly produced by marine diatoms can self-assemble directly to form gel network characteristics of the macroscopic gel phase in the natural aquatorium. Based on the experiments performed with isolated polysaccharide fractions of C. closterium and of macroaggregates gel phase, we demonstrated that the polysaccharide self-assembly into gel network can proceed independent of any bacterial mediation or interaction with inorganic particles