Scherrer Equation, L=Kλ/β.cosθ, was developed in 1918, to calculate the nano crystallite size (L) by XRD radiation of wavelength λ (nm) from measuring full width at half maximum of peaks (β) in radian located at any 2θ in the pattern. Shape factor of K can be 0.62 - 2.08 and is usually taken as about 0.89. But, if all of the peaks of a pattern are going to give a similar value of L, then β.cosθ must be identical. This means that for a typical 5nm crystallite size and λ Cukα1 = 0.15405 nm the peak at 2θ = 170° must be more than ten times wide with respect to the peak at 2θ = 10°, which is never observed. The purpose of modified Scherrer equation given in this paper is to provide a new approach to the kind of using Scherrer equation, so that a least squares technique can be applied to minimize the sources of errors. Modified Scherrer equation plots lnβ against ln(1/cosθ) and obtains the intercept of a least squares line regression, ln=Kλ/L, from which a single value of L is obtained through all of the available peaks. This novel technique is used for a natural Hydroxyapatite (HA) of bovine bone fired at 600°C, 700°C, 900°C and 1100°C from which nano crystallite sizes of 22.8, 35.5, 37.3 and 38.1 nm were respectively obtained and 900°C was selected for biomaterials purposes. These results show that modified Scherrer equation method is promising in nano materials applications and can distinguish between 37.3 and 38.1 nm by using the data from all of the available peaks.

/pdf/modified-scherrer-equation-to-estimate-more-accurately-nano-4ckval9dvr.pdf

Modified Scherrer Equation to Estimate More Accurately Nano-Crystallite Size Using XRD

http://www.u.arizona.edu/~mstiner/pdf/Stiner_etal1995.pdf

Differential Burning, Recrystallization, and Fragmentation of Archaeological Bone

It is unequivocal that prolactin is an influential hormone in murine mammary tumorigenesis The Berenblum hypothesis (7), a well-known theoretical model of tumorigenesis that depicts this oncogenic process as a two-step mechanism, ie, initiation and promotion, is a conceptual scheme in which the action of prolactin in mammary tumorigenesis may be understood According to this conceptual model, prolactin would participate in both the initiation and promotion steps of mammary tumorigenesis, In the initiation phase, variations in prolactin secretion appear to influence the metabolism of the mammary epithelium, so that the epithelium would be either more receptive to or refractory to an initiating agent (eg, chemical carcinogen, physical carcinogens, oncogenic viruses, ets) ie, a permissive action In the promotion phase, prolactin may act as either a promoter or an antipromoter of the "transformed" mammary epithelium In promotion, the hormone may either directly or indirectly (via the ovary) stimulate mitotic activity of the "transformed" epithelium In antipromotion the hormone, in the presence of requisite hormones (eg, glucocorticoids), may synergistically induce differentiation (eg, lactation) in the "transformed" epithelium A tumor would result in the former (promotion) but not in the latter (antipromotion) case Whether or not prolactin is significantly influential in human breast tumorigenesis remains to be determined This is an extremely important area of research which is justifiably receiving increased attention For if prolactin can be shown to influence human breast epithelium in a manner similar to its effect on rodent mammary tissue, then prophylactic and/of chemotherapeutic control of human breast tumorigenesis may be feasible by appropriate drug-mediated prolactin suppression

https://cancerres.aacrjournals.org/content/canres/37/4/951.full.pdf

Prolactin and Murine Mammary Tumorigenesis: A Review

Rat liver mitochondria allowed to accumulate maximal amounts of Ca++ and HPO4= ions from the suspending medium in vitro during respiration have a considerably higher specific gravity than normal mitochondria and may be easily separated from the latter by isopycnic centrifugation in density gradients of sucrose or cesium chloride. When the mitochondria are allowed to accumulate less than maximal amounts of Ca++ and HPO4= from the medium, they have intermediate specific gravities which are roughly proportional to their content of calcium phosphate. Maximally "loaded" mitochondria are relatively homogeneous with respect to specific gravity. Correlated biochemical and electron microscopic studies show that Ca++-loaded mitochondria contain numerous dense granules, of which some 85 per cent are over 500 A in diameter. These granules are electron-opaque not only following fixation and staining with heavy metal reagents, but also following fixation with formaldehyde, demonstrating that the characteristic granules in Ca++-loaded mitochondria have intrinsic electron-opacity. The dense granules are almost always located within the inner compartment of the mitochondria and not in the space between the inner and outer membranes. They are frequently located at or near the cristae and they often show electron-transparent "cores." Such granules appear to be made up of clusters of smaller dense particles, but preliminary x-ray diffraction analysis and electron diffraction studies have revealed no evidence of crystallinity in the deposits. The electron-opaque granules decrease in number when the Ca++-loaded mitochondria are incubated with 2,4-dinitrophenol; simultaneously there is discharge of Ca++ and phosphate from the mitochondria into the medium.

/pdf/effect-of-active-accumulation-of-calcium-and-phosphate-ions-3dw5qislqv.pdf

Giraud V. Foster

Papers

Burnt bones and teeth: an experimental study of color, morphology, crystal structure and shrinkage

Multifactorial regulation of prolactin secretion

Control of polypeptide hormones by enzymatic degradation.

Effect of temperature on uptake and extrusion of water by isolated rat-liver mitochondria.

Hyperprolactinemia and Polycystic Ovarian Syndrome