A survey of snellen acuity sizes and linance contrasts of letters on signs visible from the front of the college of optometry building at PU

A survey of snellen acuity sizes and linance contrasts of letters on signs visible from the front of the college of optometry building at P

Effect of strain rate on the formation of nanocrystallites in an Al-based amorphous alloy during nanoindentation

Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The article originally appeared in Journal of Applied Physics 93, 9287 (2003) and may be found at http://jap.aip.org/resource/1/japiau/v93/i11/p9287_s1.The effect of deformation by nanoindentation on nanocrystallization in amorphous Al90Fe5Gd5Al90Fe5Gd5 was investigated by transmission electron microscopy. Massive precipitation of nanocrystallites is observed within the indents. Under the quasistatic condition used, a temperature rise due to adiabatic heating is likely negligible, confirming that plastic deformation can induce crystallization without a heating effect. The nucleation of nanocrystallites is significantly affected by the strain rate. © 2003 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69990/2/JAPIAU-93-11-9287-1.pd

Characterization and modulation of drug resistance of human paediatric rhabdomyosarcoma cell lines

The role of multidrug resistance (MDR) and p53 functional status in the treatment of paediatric rhabdomyosarcoma is unclear. We have characterized a panel of seven human rhabdomyosarcoma cell lines for MDR and p53 phenotype. None of the cell lines had P-glycoprotein (P-gp) or multidrug resistance-related protein (MRP) detectable by Western blotting, whereas immunohistochemistry suggested that very low levels of MDR proteins may be present in some of the lines. RT-PCR studies indicated that mdr-1, mrp-1 and lrp mRNA was present in 5/7, 7/7 and 5/7 lines respectively. The function of p53 is compromised in six of the lines, either through mutation of the p53 gene or by overexpression of mdm-2. The sensitivity of many of the cell lines to vincristine could be modulated above 2-fold and as high as 16-fold using two modulating agents, PSC833 and VX710 (with VX710 being a significantly more potent modulator of the rhabdomyosarcoma lines). PSC833 also increased vincristine accumulation in all of the lines from 1.2- to 2.2-fold. These results suggest that some of these cell lines have low levels of multidrug resistance. The level of MDR proteins is very low and therefore difficult to detect, but may be sufficient to confer low-level, but clinically relevant, resistance to some cytotoxic agents, especially vincristine. These cell lines will therefore provide a suitable model to test new strategies in treatment and for further understanding relationships between protein expression and drug resistance. © 2000 Cancer Research Campaig

X-linked anaemia of mice: An hereditary disorder of iron absorption

The X-linked anaemia of mice (gone symbol, sla) is hypoehroxato and microcytic in character. Typically, the mean corpuscular haemoglobin concentration, the mean cell volume and the mean cell diameter are reduced. Anaemia is moderately severe in young hemizygous male and homozygous female mice, and regresses spontaneously with age. Heterozygous female animals show little or no haematological abnormality, and duality of the red cell population is not seen. The iron stores of anaemic mice, as determined both chemically and histochemically, are depleted at all ages. The clearance of iron from the plasma le rapid and the appearance of radio-iron in the red cells, after parenteral injection, is both greater and more rapid than normal. The serum iron concentration is low and the total serum iron binding capacity is elevated, as is the free erythrocyte protoporphyrin concentration. The anaemia responds well to parenteral iron dextran. Together, these findings are characteristic of iron deficiency. In contrast to the usual situation in iron deficiency in man and other mammals, intestinal iron absorption is not increased in X-linked anaemia of mice; indeed a significantly-low level of absorption of inorganic iron at three dose levels (0.1, 1.0 and 10 mug) has been found. Histo-chemical studies reveal abnormal accumulation of stainable iron in the mucosal epithelium of the small bowel of anaemic and heterozygous mice. These findings imply that the deficiency of iron is a consequence of malabsorption of iron by the small bowel, probably as a result of a primary, genetically controlled, fault in the metabolic processes of iron transfer from the mucosa cell to the plasma. The histochomical findings in the mucosa epithelium of heterozygous carriers are consistent with, although they do not constitute proof of the provisions of the Lyon hypothesis of X-chromosome inactivation. X-linked mouse anaemia does not, at present, seem to be a model for any known form of heritable human anaemia, but is potentially a useful tool in the investigation of the still mysterious processes whereby iron is transferred from the mucosal epithelium to the plasma. A hypothetical model explaining known features of iron absorption, and incorporating possible sites of action of the sla gene, is presented and discussed. It is postulated that the sla gene controls the production either of an enzyme ("iron transferase") necessary for the transfer of iron to the plasma from the mucosal epithelial cell of the small bowel, or of a carrier substance ("cytoferrin") to which iron must be bound for this transfer to be achieved

Laser surface colouring of titanium for contemporary jewellery

This paper describes work which emerged through a need to understand more about the potential of laser surface engineering for use in the creative industries. The method of creation of contemporary jewellery pieces and the resultant 'Ocular' jewellery series are described from the creative point of view. The work demonstrates how laser controlled oxide growth on Ti–6Al–4V alloy under ambient conditions can be used as an artistic tool by producing precisely defined colours. Use of the method to produce regular areas of even colour and to reproduce freehand drawings on a titanium alloy surface is described. Analysis highlights interference as the main colouring mechanism and suggests a graded surface layer, progressing from an outer layer of TiO2 to lower layers rich in TiO and Ti2O. The model of research by practice presented in this paper offers a contribution to the current debate on partnerships between art and science and engineering