Thermoresponsive polymer gating system on mesoporous shells of silica particles serving as smart nanocontainers

Spherical silica nanoparticles with solid cores and mesoporous shells (SCMS) were decorated with thermoresponsive polymer brushes that were shown to serve as macromolecular valves to control loading and unloading of a model dye within the mesopores. Thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) brushes were grafted from the surfaces of both solid core (SC) and SCMS particles of similar size using surface-initiated atom transfer radical polymerization. Both systems based on porous (SCMS-PNIPAM) and nonporous (SC-PNIPAM) particles were characterized using cryo-TEM, thermogravimetry and elemental analysis to determine the structure and composition of the decorated nanoparticles. The grafted PNIPAM brushes were found to be responsive to temperature changes enabling temperature-controlled gating of the pores. The processes of loading and unloading in the obtained systems were examined using a model fluorescent dye—rhodamine 6G. Polymer brushes in SCMS-PNIPAM systems were shown to serve as molecular valves enabling significant adsorption (loading) of the dye inside the pores with respect to the SC-PNIPAM (no pores) and SCMS (no valves) systems. The effective unloading of the fluorescent cargo molecules from the decorated nanoparticles was achieved in a water/methanol solution. The obtained SCMS-PNIPAM particles may be used as smart nanocontainers or nanoreactors offering also facile isolation from the suspension due to the presence of dense cores

Perceptual model for adaptive local shading and refresh rate

When the rendering budget is limited by power or time, it is necessary to find the combination of rendering parameters, such as resolution and refresh rate, that could deliver the best quality. Variable-rate shading (VRS), introduced in the last generations of GPUs, enables fine control of the rendering quality, in which each 16×16 image tile can be rendered with a different ratio of shader executions. We take advantage of this capability and propose a new method for adaptive control of local shading and refresh rate. The method analyzes texture content, on-screen velocities, luminance, and effective resolution and suggests the refresh rate and a VRS state map that maximizes the quality of animated content under a limited budget. The method is based on the new content-adaptive metric of judder, aliasing, and blur, which is derived from the psychophysical models of contrast sensitivity. To calibrate and validate the metric, we gather data from literature and also collect new measurements of motion quality under variable shading rates, different velocities of motion, texture content, and display capabilities, such as refresh rate, persistence, and angular resolution. The proposed metric and adaptive shading method is implemented as a game engine plugin. Our experimental validation shows a substantial increase in preference of our method over rendering with a fixed resolution and refresh rate, and an existing motion-adaptive techniqu

Dzieci urodzone z zarodków przechowywanych w stanie zamrożenia przez 10 lat. Analiza 5 przypadków

Faced with a scientific and legal debate on human embryo cryopreservation in Poland we show 5 documented clinical cases of successful thawing and transfer of embryos cryopreserved for a long period of time (8-11 years), resulting in successful delivery by the biological or the recipient mother. Cases described include patients with different infertility diagnoses, subjected to different hormonal stimulation treatments. Different oocyte fertilization methods were performed, and the obtained embryos were frozen after 2, 3 or 4 days of in vitro culture using methods employing various cryoprotective agents and freezing curves. As a result of performed thawing and transfer procedures normal, healthy babies were born. Our results are consistent with the international reports on successful long-term storage of embryos, (including the longest known period of over 19 years) resulting in no detectable reduction of the developmental potential after thawing. In light of data shown here, we do not see any medical or biological reasons for legally-regulated limitation of the period of frozen embryo storage. Moreover, if frozen, long-term stored embryos are not threatened by destruction band if prenatal adoption is a real, clinically documented option, we fail to see any reason for legal limitations of embryo cryopreservation in human infertility treatment.W kontekście naukowej i legislacyjnej debaty dotyczącej kriokonserwacji zarodków człowieka w Polsce przedstawiamy 5 udokumentowanych przypadków wieloletniego (przez okres 8-11 lat), skutecznego przechowywania zarodków zakończonego urodzeniem dzieci przez ich biologiczną matkę lub przez matkę adopcyjną. W opisanych przypadkach diagnozowano rożne przyczyny niepłodności. Zastosowano rożne metody hormonalnej stymulacji. Zamrażane były zarodki w rożnych stadiach rozwoju po hodowli in vitro trwającej 2, 3 lub 4 dni, przy udziale rożnych środków osłaniających. W efekcie przeprowadzonych kriotransferów urodziły się zdrowe, prawidłowo rozwinięte dzieci. Przedstawione dane potwierdzają wcześniejsze międzynarodowe doniesienia o możliwości wieloletniego przechowywania (najdłuższy znany przypadek to 19 lat) zamrożonych zarodków bez uszczerbku dla ich zdolności życiowych. W świetle tych danych nie znajdujemy biologicznych czy medycznych przesłanek do ustawowego ograniczania okresu przechowywania kriokonserwowanych zarodków. Tym samym, skoro zamrożone zarodki nie są skazane na biologiczną degradację a ich prenatalna adopcja jest absolutnie realną możliwością, nie widzimy podstaw do prawnego ograniczania stosowania metody kriokonserwacji w leczeniu niepłodności

Anionic polymer brushes for biomimetic calcium phosphate mineralization : a surface with application potential in biomaterials

This article describes the synthesis of anionic polymer brushes and their mineralization with calcium phosphate. The brushes are based on poly(3-sulfopropyl methacrylate potassium salt) providing a highly charged polymer brush surface. Homogeneous brushes with reproducible thicknesses are obtained via surface-initiated atom transfer radical polymerization. Mineralization with doubly concentrated simulated body fluid yields polymer/inorganic hybrid films containing AB-Type carbonated hydroxyapatite (CHAP), a material resembling the inorganic component of bone. Moreover, growth experiments using Dictyostelium discoideum amoebae demonstrate that the mineral-free and the mineral-containing polymer brushes have a good biocompatibility suggesting their use as biocompatible surfaces in implantology or related fields