Title Stabilization of Membrane Pores by Packing

We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks tending to re-seal or grows without bound til to membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a multipore membrane system, the distribution of pore size and associated pore lifetime are calculated within the mean field approximation. We predict that, above certain temperature when the effective line tension becomes negative, the membrane exhibits a dynamic sieve-like porous structure.Comment: 4 pages, 4 figure

Disentangling the sources of ionizing radiation in superconducting qubits

Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and γ-rays emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We present a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment

Disentangling the sources of ionizing radiation in superconducting qubits

Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and gamma's emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We develop a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment

PEG Branched Polymer for Functionalization of Nanomaterials with Ultralong Blood Circulation

Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched-polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NP) and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly-(g-glutamic acid) (gPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pHs, at elevated temperatures and in serum. Morever, the polymer-coated SWNTs exhibit remarkably long blood circulation (t1/2 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultra-long blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery

Рентгенологическая картина респираторного дистресс-синдрома у новорожденных с низкой и экстремально низкой массой тела

Introduction. Respiratory distress syndrome (RDS) is characterized by immaturity of lung tissue, surfactant deficiency and is a common cause of mortality in premature infants. X-ray is the main method for determining the causes and severity of respiratory failure in newborns.Purpose. Systematization of the results of X-ray examination of the lungs of newborns with varying degrees of prematurity, compared with autopsy data.Materials and methods. The analysis of X-ray data and sectional material of 32 premature infants with low and extremely low body weight who died with clinical manifestations of RDS was performed.Research results. The article provides a comparative analysis of various types of radiological changes in the lungs (reticulo-nodular pulmonary pattern (n=10), cellular deformity of the pulmonary pattern (n=5), «air bronchogram» (n=20), «air leakage» syndrome (n=6), focal-confluent shadows/infiltrative-like foci of darkening (n=9)) and autopsy results of premature newborns.Conclusion. The greatest number of coincidences of radiological and histological data took place in BPD (80%), the smallest — in pulmonary hemorrhages (20%). The coincidence of conclusions for pneumonia and GM disease is 58–56%, respectively. Difficulty in the differential diagnosis of the X-ray picture of the lungs in low birth-weight infants lies in the frequent combination of pathological conditions. Respiratory failure with a wide range of pathological changes in the lungs developed in 15 (53,6%) newborns in the absence of criteria for surfactant insufficiency against the background of respiratory support.Введение. Респираторный дистресс-синдром (РДС) характеризуется незрелостью легочной ткани, недостаточностью сурфактанта и является частой причиной смерти у недоношенных новорожденных. Рентгенография является основным методом для определения причин и степени выраженности респираторной недостаточности у новорожденных.Цель. Систематизация результатов рентгенологического исследования легких новорожденных с различной степенью недоношенности, сопоставленных с аутопсийными данными.Материалы и методы. Выполнен анализ рентгенологических данных и секционного материала 32 недоношенных новорожденных с низкой и экстремально низкой массой тела, умерших с клиническими проявлениями РДС.Результаты исследования. В статье приведен сравнительный анализ различных типов рентгенологических изменений легких (ретикуло-нодулярный легочный рисунок (n=10), ячеистая деформация легочного рисунка (n=5), «воздушная бронхограмма» (n=20), синдром «утечки воздуха» (n=6), очагово-сливные тени/инфильтративно-подобные фокусы затемнения (n=9)) и результатов аутопсий недоношенных новорожденных.Заключение. Наибольшее количество совпадений рентгенологических и гистологических данных имело место при БЛД (80%), наименьшее — при легочных геморрагиях (20%). Совпадение заключений при пневмонии и болезни ГМ — в 58–56% соответственно. Сложность дифференциальной диагностики рентгенологической картины легких у маловесных новорожденных заключается в частом сочетании патологических состояний. У 15 (53,6%) новорожденных при отсутствии критериев сурфактантной недостаточности на фоне респираторной поддержки развивалась дыхательная недостаточность с широким спектром патологических изменений в легких

Evidence for a Spatially Modulated Superfluid Phase of ³He under Confinement

In superfluid $^3$He-B confined in a slab geometry, domain walls between regions of different order parameter orientation are predicted to be energetically stable. Formation of the spatially-modulated superfluid stripe phase has been proposed. We confined $^3$He in a 1.1 $\mu$m high microfluidic cavity and cooled it into the B phase at low pressure, where the stripe phase is predicted. We measured the surface-induced order parameter distortion with NMR, sensitive to the formation of domains. The results rule out the stripe phase, but are consistent with 2D modulated superfluid order.Comment: 9 pages, 9 figure