Atrial-Synchronized Demand Heart Pacing

A universal heart pacing method is proposed, making use of the atrial-synchronized and demand operation modes. The system includes an ECG-sensing network for control of the pacing action. Special logic design provides for processing the P- and QRS-waves in two parallel channels.     

Splits in the self following immigration: An adaptive defense or a pathological reaction?

This study examines the extent to which splits in the sense of self following immigration can be seen to be an adaptive defense, allowing the self time to adapt and adjust to a new reality or rather a pathological reaction to the trauma of migration. In-depth interviews were conducted with 68 emerging adult immigrants in Israel from the Former Soviet Union around sense of self and the immigration experience. One year following the first interview, levels of functioning were assessed. Results showed that attempts to resolve splits (self/object) early after immigration led to an initially lower level of psychological symptoms, but one year later to an increased level of symptoms, suggesting that attempts of precocious resolution are likely to lead to subsequent adaptation difficulties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Combinatorial Library of Lipid Nanoparticles for RNA Delivery to Leukocytes

Lipid nanoparticles (LNPs) are the most advanced nonviral platforms for small interfering RNA (siRNA) delivery that are clinically approved. These LNPs, based on ionizable lipids, are found in the liver and are now gaining much attention in the field of RNA therapeutics. The previous generation of ionizable lipids varies in linker moieties, which greatly influences in vivo gene silencing efficiency. Here novel ionizable amino lipids based on the linker moieties such as hydrazine, hydroxylamine, and ethanolamine are designed and synthesized. These lipids are formulated into LNPs and screened for their efficiency to deliver siRNAs into leukocytes, which are among the hardest to transfect cell types. Two potent lipids based on their in vitro gene silencing efficiencies are also identified. These lipids are further evaluated for their biodistribution profile, efficient gene silencing, liver toxicity, and potential immune activation in mice. A robust gene silencing is also found in primary lymphocytes when one of these lipids is formulated into LNPs with a pan leukocyte selective targeting agent (β₇ integrin). Taken together, these lipids have the potential to open new avenues in delivering RNAs into leukocytes.     

Coordinated motion planning for two independent robots

We present anO(n ²) algorithm for planning a coordinated collision-free motion of two independent robot systems of certain kinds, each having two degrees of freedom, which move in the plane amidst polygonal obstacles having a total ofn corners. We exemplify our technique in the case of two planar Stanford arms, but also discuss the case of two discs or convex translating objects. The algorithm improves previous algorithms for this kind of problems, and can be extended to a fairly simple general technique for obtaining efficient coordinated motion planning algorithms.     

Solar Carboreduction of Alumina Under Vacuum

A preliminary study on carboreduction of alumina under vacuum, which was necessary before the solar reactor design, has been performed using an induction heater equipped with a graphite susceptor as the sample holder surrounded by a ceramic tube serving as the metal vapor deposit site. The primary objective was to study the forward and backward reactions as a function of temperature and CO partial pressure. It was concluded that at reaction temperatures above 1600°C and at an average CO partial pressure below 0.2 mbar, the amount of residual by-products in the graphite crucible was negligible, whereas tests with an average CO partial pressure of 2.6 mbar required temperatures above 1800°C to convert the stoichiometric reactants pellets fully. It was concluded that pure aluminum can be found only at deposit sites with temperatures below 600–700°C in tests with temperature and pressure suitable to prevent the volatile suboxide formation in the forward reaction. Based on these results, the solar reactor was designed with a sharp temperature drop from the hot to the cold area. The results of solar tests with different levels of CO partial pressure and temperature conditions reveal that the alumina to aluminum conversion is about 90% for reaction temperatures above the minimum temperature required for full conversion as predicted by the thermodynamic calculations at the appropriate pressure. However, at lower temperatures, a significant amount of solid Al₄C₃, Al₄CO₄, and volatile Al₂O can be formed in the forward reaction, leading to an increase of the residual by-product in the reactant holder as well as lower purity of the aluminum product and an increase of the alumina content in the deposits at the cold reactor’s zone. The observed nanocrystalline and amorphous morphology of the deposits caused by fast cooling in the cold zone will also be discussed.     

Pulsed Laser Induced Decomposition of Energetic Polymers: Comparison of ultraviolet (355 nm) and infrared (9.3 μm) initiation

Irradiation of the energetic polymer GAP (glycidyl azido polymer) by a high power pulsed UV laser leads to its rapid decomposition. A large amount of solid and gaseous material is released, and in the presence of an inert gas, a shock wave develops. Comparison with an inert polymer indicates that the energy released by the exothermicity of the decomposition reaction contributes significantly to the shock formative energy. The energy released in the micro-explosion can be estimated from the analysis of the shock front propagation velocity. It is found that irradiation of polymers in which GAP is diluted by an inert polymer, may lead to a higher shock intensity than irradiation of neat GAP. Possible causes for this apparent inconsistency (which is not observed upon initiation by a pulsed infrared laser) are discussed.