Expression of a human homeobox-containing gene is regulated by 1,25(OH)2D3 in bone cells

The seasonal variation in the nutrient composition of Enhydra fluctuans and Marsilea quadrifolia, two edible semi-aquatic plants, was studied in order to promote their consumption as green leafy vegetables. Both plants had a high crude protein content throughout all harvesting seasons. Enhydra fluctuans had a low ash content and was a good source of beta-carotene (3.7 to 4.2 mg/100 g on a fresh weight basis). Marsilea quadrifolia exhibited wide fluctuations between seasons and was not very promising in nutrient composition when compared to other commonly used green leafy vegetables.     

The effects of proteoglycan surface patterning on neuronal pathfinding

Protein micropatterning techniques are increasingly applied in cell choice assays to investigate fundamental biological phenomena that contribute to the host response to implanted biomaterials, and to explore the effects of protein stability and biological activity on cell behavior for in vitro cell studies. In the area of neuronal regeneration the protein micropatterning and cell choice assays are used to improve our understanding of the mechanisms directing nervous system during development and regenerative failure in the central nervous system (CNS) wound healing environment. In these cell assays, protein micropatterns need to be characterized for protein stability, bioactivity, and spatial distribution and then correlated with observed mammalian cell behavior using appropriate model system for CNS development and repair. This review provides the background on protein micropatterning for cell choice assays and describes some novel patterns that were developed to interrogate neuronal adaptation to inhibitory signals encountered in CNS injuries.     

Empirical equations for the principal refractive indices and column angle of obliquely deposited films of tantalum oxide, titanium oxide, and zirconium oxide

Values of the transmittance T(s) and the phaseretardation D were recorded in situ at two angles duringthe growth of thin films of tantalum oxide, titanium oxide, andzirconium oxide for deposition angles theta(nu) in the range40 degrees -70 degrees . Column angles for the same films were determinedex situ from scanning electron microscopy photographs ofdeposition-plane fractures. We show that the experimental columnangles are smaller than the corresponding values predicted by thetangent-rule equation psi = tan(-1)(0.5 tan theta(nu)) and that the experimental values fit a modifiedform of the equation psi = tan(-1)(E(1) tan theta(nu)) where E(1) is less than 0.5. We also show that theprincipal refractive indices are represented well by quadraticfunctions of the deposition angle, for example, n(1)(theta(nu)) = A(0) + A(2) theta(nu)(2).     

Vacuum deposition of chiral sculptured thin films with high optical activity

We present the technique of bideposition to realize thin-film helicoidal bianisotropic mediums (TFHBM's) that exhibit high optical activity. We show, by experiment as well as by simulation, that the optical rotation produced by these chiral sculptured thin films is roughly proportional to the square of the local linear birefringence. Experimental measurements on bideposited TFHBM's of titanium oxide yield a typical value of 5 degrees /mum for the effective specific rotation in the short-wavelength regime; the corresponding value determined for the standard unideposited TFHBM's is 1 degrees /mum. Both types of TFHBM's are highly optically active in comparison with quartz, fluorite films, and cholesteric liquid crystals. Bideposited TFHBM's will lend themselves to many different types of optical devices.     

Dispersion equations for vacuum-deposited tilted-columnar biaxial media

We consider the application of the Bragg-Pippard (BP) equations for form birefringence to a tilted-columnar biaxial thin film with columns of index n(c) and voids of known index n(v). In such a situation the three forward BP equations that express the principal refractive indices n(1), n(2), and n(3) as functions of n(c), n(v), the packing fraction p(c), and the depolarization factors L(1), L(2), and L(3) can be inverted. The procedure described for adding dispersion to the principal indices involves entry to the BP model via the inverted equations, modification of n(c) to allow for dispersion, and then exit from the model via the forward BP equations. We discuss the introduction of composite columns to the model to allow for angular dependence of n(c) and the selection of suitable dispersion functions for bulk tantalum oxide, titanium oxide, and zirconium oxide. Theory and experiment both show that the dispersion of the normal-incidence birefringence Dn of the thin films is several times larger than the dispersion of the individual principal refractive indices.     

Comparison of sinusoidal and pulse modulation techniques for generating optical frequency reference combs

The optical frequency combs generated by pulse and sinusoidal modulation of an LiNbO/sub 3/ Mach-Zehnder device are compared and contrasted. It is shown that the former operates with lower drive, although being restricted to narrower tooth spacings than offered by the sinusoidal technique.<>     

Optical domain frequency translation of a modulated optical carrier

It is demonstrated that a frequency translating recirculating optical loop can be used as a means of frequency translating a digitally modulated optical carrier from one frequency to another without the need for the modulated carrier to exit the optical domain.<>     

Infection of sheep with adult and larval Ostertagia circumcincta: abomasal morphology

The infection of parasite-naive sheep with approximately 15,000 adult Ostertagia circumcincta via abomasal cannulae resulted in marked changes in the structure and function of the abomasum. The functional changes, which have been characterised previously, included elevated abomasal pH and increased serum concentrations of pepsinogen and gastrin. Eight days after the transplant of adult worms, the abomasa of recipient animals were significantly heavier than those of controls (P < 0.001), the thickness of the fundic mucosa was greater (P < 0.01), there were fewer parietal cells (P < 0.01) and increases in the numbers of mitotic figures and mucus-producing cells. Mucous cell hyperplasia was also evident in the fundic mucosae of sheep receiving a trickle infection of infective, third-stage O. circumcincta larvae and was prominent within nodules associated with larval development. In non-nodular mucosa, there was hyperplasia of mucous cells and changes in the distribution of parietal cells. Decreases in the number of parietal cells at the gland base were offset by increases at a mid-gland level, probably due to chronic hypergastrinaemia, so that, overall, total parietal cell number was unaffected. Mucous cell hyperplasia and the diminution of parietal cell number are seen in a diverse range of disease states and may be mediated by host growth factors such as Transforming growth factor-alpha. Alternatively, the cellular and/or the secretory changes in response to the presence of adult worms are mediated by chemicals that are cytotoxic/inhibitory for parietal cells, and released by the parasites themselves.     

Stress relief induced in silicon oxide films by ultraviolet radiation

Silicon oxide films deposited by reactive evaporation in an atmosphere of oxygen are formed in a state of compressive stress. Ultraviolet irradiation, which is sometimes used to reduce the absorbance of the films at ultraviolet wavelengths, is shown to produce a substantial reduction in stress. In some cases prolonged irradiation completely removes the initial compressive stress, and the residual stress may be tensile. Results are presented for the dependence of stress on the deposition parameters, and for changes of stress with age.     

Deep states in transition metal diffused gallium phosphide

Deep level measurements have been made on transition metal diffused, n-type LPE and VPE gallium phosphide. The results are compared with untreated samples and also with crystals annealed under similar conditions to the diffused samples, but with no transition metal source.Stable deeply bound electron states have been associated with Cr, Mn, Fe, Co and Ni. Positive identifications of substitutional transition elements have been made using photoluminescence.Thermal Activation energies, typical concentrations and the energies of some optical transitions associated with these states are summarised.