Electrophoresis of Janus Particles: a Molecular Dynamics simulation study

In this work, we use Molecular Dynamics and Lattice-Boltzmann simulations to study the properties of charged Janus particles in an electric field. We show that for relatively small net charge and thick electrostatic diffuse layer mobilities of Janus particles and uniformly charged colloids of the same net charge are identical. However, for higher charges and thinner diffuse layers Janus particles always show lower electrophoretic mobility. We also demonstrate that Janus particles align with the electric field and the angular deviation from the field's direction are related to their dipole moment. We show that the latter is affected by the thickness of the electrostatic diffuse layer and strongly correlates with the electrophoretic mobility.Comment: Accepted to JC

Star polymers as unit cells for coarse-graining cross-linked networks

Reducing the complexity of cross-linked polymer networks by preserving their main macroscale properties, is key to understanding them, and a crucial issue is to relate individual properties of the polymer constituents to those of the reduced network. Here we study polymer networks in a good solvent, by considering star polymers as their unit elements, and first quantify the interaction between their centers of masses. We then reduce the complexity of a network by replacing sets of its bridged star polymers by equivalent effective soft particles with dense cores. Our coarse graining allows us to approximate complex polymer networks by much simpler ones, keeping their relevant mechanical properties, as illustrated in computer experiments on an isotropic compression.Comment: 5 pages, 8 figure

Use of combined oral contraceptives and risk of venous thromboembolism: nested case-control studies using the QResearch and CPRD databases

Objective To investigate the association between use of combined oral contraceptives and risk of venous thromboembolism, taking the type of progestogen into account. Design Two nested case-control studies. Setting General practices in the United Kingdom contributing to the Clinical Practice Research Datalink (CPRD; 618 practices) and QResearch primary care database (722 practices). Participants Women aged 15-49 years with a first diagnosis of venous thromboembolism in 2001-13, each matched with up to five controls by age, practice, and calendar year. Main outcome measures Odds ratios for incident venous thromboembolism and use of combined oral contraceptives in the previous year, adjusted for smoking status, alcohol consumption, ethnic group, body mass index, comorbidities, and other contraceptive drugs. Results were combined across the two datasets. Results 5062 cases of venous thromboembolism from CPRD and 5500 from QResearch were analysed. Current exposure to any combined oral contraceptive was associated with an increased risk of venous thromboembolism (adjusted odds ratio 2.97, 95% confidence interval 2.78 to 3.17) compared with no exposure in the previous year. Corresponding risks associated with current exposure to desogestrel (4.28, 3.66 to 5.01), gestodene (3.64, 3.00 to 4.43), drospirenone (4.12, 3.43 to 4.96), and cyproterone (4.27, 3.57 to 5.11) were significantly higher than those for second generation contraceptives levonorgestrel (2.38, 2.18 to 2.59) and norethisterone (2.56, 2.15 to 3.06), and for norgestimate (2.53, 2.17 to 2.96). The number of extra cases of venous thromboembolism per year per 10 000 treated women was lowest for levonorgestrel (6, 95% confidence interval 5 to 7) and norgestimate (6, 5 to 8), and highest for desogestrel (14, 11 to 17) and cyproterone (14, 11 to 17). Conclusions In these population based, case-control studies using two large primary care databases, risks of venous thromboembolism associated with combined oral contraceptives were, with the exception of norgestimate, higher for newer drug preparations than for second generation drugs

Устойчивость к меди in vitro пероксидазы листьев Populus Deltoides из насаждений металлургических предприятий Донбасса

Influence of copper ions concentration gradient on the activity of peroxidase prepared from Populus deltoidеs Marsh. leaves was studied in vitro for plants growing near the mercury combine and zinc factory of Donbass and in a city square. Leaf peroxidase of plants from industrial territories was shown to be more resistant to Cu2+ inhibiting action.Іn vitro визначали вплив градієнта концентрацій іонів міді на активність пероксидази, виділеної з листків рослин Populus deltoidеs Marsh., що ростуть поряд із металургійним і ртутним комбінатами та цинковим заводом в умовах міського скверу Донбасу. Виявлено вищу стійкість до інгібуючої дії Cu2+ пероксидази листків рослин промислових насаджень.Іn vitro визначали вплив градієнта концентрацій іонів міді на активність пероксидази, виділеної з листків рослин Populus deltoidеs Marsh., що ростуть поряд із металургійним і ртутним комбінатами та цинковим заводом в умовах міського скверу Донбасу. Виявлено вищу стійкість до інгібуючої дії Cu2+ пероксидази листків рослин промислових насаджень

Organic derivatives of antimony. IV. Association of alkoxy and chloroalkoxy derivatives of antimony (III) and (V)

1. Chlorotetramethoxyantimony was obtained by the action of acetyl chloride on pentamethoxyantimony. 2. Triethoxy-, tripropoxy-, and triisobutoxyantimony are partially associated under conditions of cryoscopy in cyclohexane, while triisopropoxy- and tri-tert-butoxyantimony are monomeric. Under ebullioscopy conditions in CCl4, 2-ethoxy-4-methyl-1, 3,2-dioxastibinane exists in a monomeric form. 3. According to the data of cryoscopic and ebullioscopic measurements, pentaethoxyantimony exists in benzene in a dimeric form. Dimers of tetrachloromethoxy-, trichlorodimethoxy-, and dichlorotrimethoxyantimony are partially dissociated in benzene. © 1979 Plenum Publishing Corporation

Organic derivatives of antimony - 3. Alkoxy and chloroalkoxy derivatives of antimony

1. The action of an excess of chlorine on the corresponding alkoxy- and chloroalkoxy derivatives of Sb(III) produced trichlorodimethoxy-, dichlorotrimethoxy-, and trichlorodiethoxyantimony, which have not been described in the literature, as well as tetrachloromethoxy- and dichlorotriethoxyantimony. 2. The action of acetyl chloride on pentaethoxyantimony yielded chlorotetraethoxyantimony. 3. The ester interchange of pentaethoxyantimony with methanol yielded pentamethoxyantimony. 4. The reaction of SbCl3 with trimethoxy- and triethoxyantimony produced chlorodimethoxy-, dichloromethoxy-, and chlorodiethoxyantimony. © 1977 Plenum Publishing Corporation

Stereochemistry of organophosphorus compounds 15. Synthesis and permutational lability of 1,6,10-trioxa-8,8-dimethyl[(5-methoxy)-5-phosphaspiro(4.5)]dec-2-ene

1. We have synthesized 1,6,10-trioxa-8,8-dimethyl[(5-methoxy)-5-phosphaspiro(4.5)]dec-2-ene, a compound in which the trigonal-bipyramidal phosphorus bond arrangment undergoes pseudorotation at temperatures below 36°C. Thermodynamic activation parameters for the pseudorotation process have been evaluated from the observed temperature variation of the parameters of the1H NMR spectrum. 2. The enol acetate of β-neopentylglycolphosphonepropionic aldehyde has been prepared. © 1978 Plenum Publishing Corporation

Contents of heavy metals in fructicose epiphytic lichens of Karelia as indicator of atmospheric transport of pollutants

Results of studies of heavy metals contents in fruticose epiphytic lichens in Karelia are presented and the influence of different sources on the elemental composition of lichens has been estimated. It has been shown, that long-range atmospheric transport influences strongly the accumulation of Pb, Zn, Cd, Sb. For Al, Fe and Co lithogenic source is the main one. In the Northern Karelia atmospheric transport of Cu, Co and Ni from metallurgic enterprises of the Murmansk Region is important source of these elements

Synthesis and properties of 2,2,2- trimethoxy-3, 5-diphenyl-3,4-diazaoxa-4-phospholene

1. Trimethyl phosphite reacts with phenylbenzoylimine to form 2,2,2-trimethoxy-3,5-diphenyl-3,4-diazaoxa-4-phospholene. 2. Saponification of the latter has given dimethyl N-benzamido-N-phenylphosphoramidate. © 1968 Consultants Bureau

Surface Roughness and Effective Stick-Slip Motion

The effect of random surface roughness on hydrodynamics of viscous incompressible liquid is discussed. Roughness-driven contributions to hydrodynamic flows, energy dissipation, and friction force are calculated in a wide range of parameters. When the hydrodynamic decay length (the viscous wave penetration depth) is larger than the size of random surface inhomogeneities, it is possible to replace a random rough surface by effective stick-slip boundary conditions on a flat surface with two constants: the stick-slip length and the renormalization of viscosity near the boundary. The stick-slip length and the renormalization coefficient are expressed explicitly via the correlation function of random surface inhomogeneities. The effective stick-slip length is always negative signifying the effective slow-down of the hydrodynamic flows by the rough surface (stick rather than slip motion). A simple hydrodynamic model is presented as an illustration of these general hydrodynamic results. The effective boundary parameters are analyzed numerically for Gaussian, power-law and exponentially decaying correlators with various indices. The maximum on the frequency dependence of the dissipation allows one to extract the correlation radius (characteristic size) of the surface inhomogeneities directly from, for example, experiments with torsional quartz oscillators.Comment: RevTeX4, 14 pages, 3 figure