The biological effects of nanohydroxyapatites and its cell toxicity have been studied using the MTT and ALP method, infrared spectrum of absorption and electrophoresis method, respectively. The nanohydroxyapatites are prepared and made by using sol-gel method, in which the parameters of process and reaction are controlled as: pH > 9, Ca/P = 1.67, sintering temperature of 1100 degrees C and sint...

Many early workers detected copper in certain plants, but attached no significance to its occurrence. Bucholz (1) and Meissner (2) in 1816 were probably the first definitely to establish the presence of copper in plant life. Sarzeau (3), in 1830, found copper in numerous plants, and since then many workers have reported the occurrence of this element, but most of them, as reviewed by Chevreul (...

Most natural (or biological) materials are complex composites whose mechanical properties are often outstanding, considering the weak constituents from which they are assembled. These complex structures, which have risen from hundreds of million years of evolution, are inspiring Materials Scientists in the design of novel materials. Their defining characteristics, hierarchy, multifunctionality,...

Damage and fatigue are ever-present facts of life. Given enough time, even the most robust material, whether man-made or natural, succumbs to the deleterious effects of cracks, fissures, and defects during normal use. Traditionally, materials engineers have approached this problem by creating damage-tolerant structures, intensive quality control before use, vigilant inspection during use, and d...

In an attempt to find a method for the determination of iron that could be used for the clinical study of iron metabolism, certain calorimetric procedures (1, 2) were studied. Some difficulties were encountered with these techniques and especially in their adaptation to the measurement of minute amounts of iron in such diverse materials as blood, food, feces, and urine. This led to the investig...

From everyday life experience, we all know that during watering or rainfall, water rolls off the leaves of many plants in the form of spherical droplets leaving the leaves themselves entirely dry. This effect can be seen in an especially impressive manner on the leaves of the sacred lotus (Nelumbo nucifera) and Tropaeolum (Tropaeolum majus). Interestingly, with the rolling off of water droplets...

As it is known, the ceramic and metallic materials, such as Ni-Cr and Co-Cr alloy serve often as a fixed dental materials of restoration in human bones, teeth and vascular stents, but they have a lot of shortcomings, such as they can result in Ni and Cr hypersusceptibility of men and ion exchange between the material and tooth, which lead the distortion and discoloration of the gingival edge an...

A means of measuring the total water of the body in vivo has been developed (1). This method involves the use of antipyrine (l-phenyl-2,3dimethylpyrazolone-5-one), the well known analgesic and antipyretic. Two methods for the determination of this compound in biological materials are described in this report. The first, an extraction procedure, is suitable for its estimation in biological fluid...

Flexoelectricity and the concomitant emergence of electromechanical size-effects at the nanoscale have been recently exploited to propose tantalizing concepts such as the creation of “apparently piezoelectric” materials without piezoelectric materials, e.g. graphene, emergence of “giant” piezoelectricity at the nanoscale, enhanced energy harvesting, among others. The aforementioned developments...

The quantitative determination of cellulose in biological materials presents some difficult problems. The moisture con~ent of cellulose varies with the relative humidity, so that accurate analyses require that moisture determinations be made under carefully standardized conditions. Cellulose ordinarily occurs in association with lignin, polyuronide hemicelluloses, and xylan cellulosans. Matrone...