Nylon 6, 6 is regarded as tough and ductile materials since it exhibit high tensile elongation to break and high drop weight impact strengths. However, under conditions of stress concentration such as in the presence of sharp notches or cracks, polyamides exhibit brittle failure. This property, evaluated as notched Izod or Charpy impact tests, indicates that unmodified polyamides exhibit relati...

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters that have a wide variety of physical properties dependent on the lengths of the pendant groups of the monomer units in the polymer. PHAs composed of mostly short-chain-length (SCL) monomers are often stiff and brittle, whereas PHAs composed of mostly medium-chain-length (MCL) monomers are elastomeric in nature. SCL-MCL PHA copolymers can...

A syndrome of red hair, blue sclera, and brittle cornea with recurrent spontaneous perforations is presented in 2 siblings of a Tunisian Jewish family. The genetic transmission of this disorder is autosomal recessive. This is the second description of this syndrome, which should be called the 'brittle cornea syndrome'. This syndrome has so far been reported only in Tunisian Jewish families.

In a pilot study two patients with brittle asthma and two with morning dipping received terbutaline or a placebo administered subcutaneously either by continuous infusion or in injections every six hours. In two patients brittle asthma was completely suppressed by terbutaline 1 mg/day given by either method. In the two others early morning dipping responded only to continuous subcutaneous infus...

BACKGROUND AND THE PURPOSE OF THE STUDY Domperidone (DOM) is a dopamine- receptor (D(2)) antagonist, which is widely used in the treatment of motion-sickness. The pharmacokinetic parameters make DOM a suitable candidate for transdermal delivery. The purpose of the present investigation was to develop transdermal delivery systems for DOM and to evaluate their physicochemical characteristics, in ...

Microbicides are being actively researched and developed as woman-initiated means to prevent HIV transmission during unprotected coitus. Along with safety and efficacy, assessing and improving compliance is a major area of research in microbicide development. We have developed carrageenan-based semisoft vaginal suppositories and have previously evaluated how physical properties such as firmness...

Recent ideas on the mechanisms controlling the initial stages of plastic flow at cracks in intrinsically brittle materials, at the ductile-brittle transition, are reviewed. New experiments on precracked specimens of Si are reported, which confirm earlier work that the ductile-brittle transition is controlled by dislocation velocity. A model has been developed in which at the ductile-brittle tra...

Thin film metal oxide coatings have been used commercially as electromagnetic filters from the UV to infrared regions for over half a century. Deposition onto a substrate has typically been accomplished using vapor deposition techniques and more recently sol–gel methods. These coatings provide very good optical and mechanical performance when applied to substrates with similar thermal and mecha...

Due to periodic variations in temperature and heavy traffic loading, hot-mix asphalt (HMA) pavements undergo considerable distress during their service life. The rheological properties of binder, when subjected complex physical chemical processes, make it stiff sometimes brittle, which ultimately plays a huge part pavement deterioration. This phenomenon is commonly known as aging. Incorporating...