BACKGROUND AND PURPOSE The purpose of this study was to determine the distribution of polyethylene glycol-conjugated superoxide dismutase in the brain, cerebrospinal fluid, and various organs. METHODS Distribution of iodine-125-labeled polyethylene glycol-conjugated superoxide dismutase was determined in three groups of male Sprague-Dawley rats: a normotensive sham control group (n = 9) and g...

BACKGROUND Aseptic loosening of total hip arthroplasties is generally caused by periprosthetic bone resorption due to tissue reactions on polyethylene wear particles. In vitro testing of polyethylene cups incorporated with vitamin E shows increased wear resistance. The objective of this study is to compare vitamin E-stabilized highly cross-linked polyethylene with conventional cross-linked poly...

BACKGROUND Large number of surgical services use laparoscopy to approach the colon. One of the concerns on the resection using this way is the high rate of cancer relapse at in- and outlet site of the surgical instruments. AIM To describe a protective device for surgical isolation in laparoscopic colectomy. METHODS The device is made of sterile polyethylene plastic cover used to protect the...

The problem of finding an optimal vertex cover in a graph is a classic NP-complete problem, and is a special case of the hitting set question. On the other hand, the hitting set problem, when asked in the context of induced geometric objects, often turns out to be exactly the vertex cover problem on restricted classes of graphs. In this work we explore a particular instance of such a phenomenon...

EDITOR’S NOTE Geopersia is published biannually by the College of Science, University of Tehran, Iran. The College of Science published “Journal of Science”, which covered all fields of basic science, from 1968 to 2010. It was then decided that the College’s journals should be more specialized, and hence publication of Geopersia was launched. Geopersia aims to publish peer-reviewed original...

ABSTRACT Vegetable cultivation requires high water use and weed control. Soil cover using recycled paper, can be an alternative to polyethylene film reduce incidence, soil temperature increase efficiency beyond reduces costs environmental pollutions. The objective of this study was evaluate the biodegradable mulch in management (WUE) lettuce crop. treatments were composed brown paper (RP), blac...

This cover page depicts a new type of reconfigurable perovskite light emitting electrochemic al (PeLEC) device, in which the external ions, such as Li+ added via ionic salt, play role internal mobile dopants forming p–i–n structure and electrical double layers at interfaces, strongly enhancing charge injection. concept is described article number 2001715 by Dmitry Gets, Jason D. Slinker, Anvar ...

We introduce the successive Hitting Set model, where the set system is not given in advance but a set generator produces the sets that contain a specific element from the universe on demand. Despite incomplete knowledge about the set system, we show that several approximation algorithms for the conventional Hitting Set problem can be adopted to perform well in this model. We describe, and exper...

We study a geometric hitting set problem involving unirectional rays and curves in the plane. We show that this problem is hard to approximate within a logarithmic factor even when the curves are convex polygonal x-monotone chains. Additionally, it is hard to approximate within a factor of 76 even when the curves are line segments with bounded slopes. Lastly, we demonstrate that the problem is ...

A novel strategy, based on the in situ generated boron-thexyl-silaboracyclic initiating sites for the polyhomologation of dimethylsulfoxonium methylide, has been developed for the synthesis of complex polyethylene-based architectures. As examples, the synthesis of a 4-arm polyethylene star, three (polystyrene)(polyethylene)2 3-miktoarm stars and a PE-branched double graft copolymer is given.