Robertsonian translocations are the most common structural chromosomal abnormalities, observed in humans, at a frequency of 1.23 per 1,000. A Robertsonian translocation involving chromosomes 13 and 14 is one of the most common constitutional rearrangements, at 0.97 per 1,000 [ [1] Nielsen J. Wohlert M. Chromosomal abnormalities among 34,910 newborn children: results from a 13-year incidence study in Åarhus. Denmark. Hum Genet. 1991; 87: 81-83 Crossref PubMed Scopus (743) Google Scholar ]. The significant phenotypic expressions associated with this translocation includes increased risk of infertility (male), miscarriage, and aneuploid offspring. There have also been scattered reports of hematopoietic disorders, primarily myeloid leukemias [ 2 Goh K.O. Bauman A.W. Townes P.L. Myeloproliferative disorder in a t(13q;14q) carrier. Cancer. 1980; 45: 327-329 Crossref PubMed Scopus (12) Google Scholar , 3 Sandberg A.A. The chromosomes in human cancer and leukemia. 1st ed. Elsevier–North Holland, New York1980 Google Scholar , 4 De Greef I. Geraedts J.P.M. Leeksma C.H.W. Malignant hematologic disorders in two Robertsonian 13;14 translocation carriers. Cancer Genet Cytogenet. 1982; 7: 181-184 Abstract Full Text PDF PubMed Scopus (15) Google Scholar ]; however, the low frequency of this translocation in the population [ 5 Hook E.B. Hamerton J.L. The frequency of chromosome abnormalities detected in consecutive newborn studies: differences between studies—results by sex and by severity of phenotypic involvement. in: Hook E.B. Porter I.H. Population cytogenetics: studies in humans. Symposium on Human Population Cytogenetics (1975: Albany, NY). Academic Press, New York1977: 63-79 Google Scholar , 6 Gosden J.R. Gosden C. Lawrie S. Mitchell A.R. The fate of DNA satellites I, II, III and ribosomal DNA in a familial dicentric chromosome 13;14. Hum Genet. 1978; 41: 131-141 Crossref PubMed Scopus (24) Google Scholar ] has made it difficult to reach any definite conclusion.

The effect of the particle size on the mechanical properties of polymeric composites reinforced with spherical particles was investigated. The size of particles varied from macro (0.5mm) to nano (15nm) scale. It was found that particle sizes at micro scale have little influence on the Young’s modulus of the composite and that Young’s modulus increases as the size of particles decreases at nano scale. It was also observed that tensile strength of the composite is significantly dependent on particle size. At 1vol% loading, the tensile strength increased as the particle size decreased. However, the trend for the composite with alumina nanoparticles of 3% volume fraction was found to be opposite. TEM and SEM micrographs showed higher likelihood of poor dispersions in the composite with 3vol% nanoparticles than that with 1vol%. To understand the effect of the particle size in micron scale on the failure process, finite element analyses showed that total strain energy release rate for particle/matrix debonding growth decreases as particle size decreases and that sliding fracture mode becomes dominant as the debonding grows. It was found that interfacial fracture toughness does not depend on particle size but increases substantially when the sliding fracture mode prevails.

Portal vein aneurysms are not commonly encountered in clinical practice. They are usually extrahepatic and occasionally intrahepatic. Most are asymptomatic and detected incidentally; they may be associated with portal hypertension. Complications include thrombosis, rupture and formation of portosystemic shunts. A review of the Englishlanguage literature revealed 47 cases of portal vein aneurysm, but there has been only one Englishlanguage report in more than the last three decades of a such an aneurysm leading to cholestasis. We present such a case, together with a comprehensive review of the literature on portal vein aneurysms.

Vitamin binding proteins (VBP) are elaborated in the liver and perform the function of carrying vitamins to the cells. There are specific binding proteins for Folic acid (FBP), Riboflavin (RCP), Retinol (RBP) and B12 (Transcobalamin). These VBPs also serve to transport the respective vitamins transplacentally for fetal nutrition and secreted into the milk for nutrition of the neonate. Immunoneutralization of RCP in the pregnant rat and the monkey results in termination of pregnancy. The present study was undertaken to elucidate the role of FBP and RCP in placental function and maintenance of pregnancy. The study was designed as a laboratory study using term human placenta for immunohistochemical analysis and human umbelical vein endothelial cells (HUVEC) in tissue culture. Immunohistochemical localization of FBP and RCP was performed using a standard double antibody immunoperoxidase technique. Term placenta were obtained after proper institutional board review and paraffin sections were serially treated with rabbit antibody to FBP or RCP, biotynylated goat antirabbit globulin, avidin-peroxidase conjugate and Diaminobenzidine tetrahydrochloride to develop a brown color. HUVECs were plated and cultured in 6 well plates in endothelial cell basal medium containing growth factors and 20% serum, till they became about 70% confluent. Serum was reduced to 2% and cells were further cultured overnight, washed and further cultured in Krebs solution buffered with HEPES for 30 minutes before the start of the experiment. They were divided into 5 groups and treated for 30 minutes with 5 or 50 microgram RCP (gr 2 & 3), 5 or 50 micrograms of FBP (gr. 4 & 5) or nontreated control (gr.1). Nitric Oxide (NO) was measured in medium by a modified Greiss reaction which measures nitrate and nitrite produeced as end products. We observed specific immunohistochemical localization of RCP and FBP in the syncitiotrophoblast of the placental villi. Localization was also seen in the endothelial layer of the placental vasculature and lead us to investigate the effects of these two VBPs on endothelial NO production. There was a dose dependent increase in NO production by RCP. A two fold increase with 5 microgram and a four fold increase at 50 microgram treatment was observed. FBP was more potent and showd a maximal five fold increase at the 5 microgram treatment level itself. This is the first demonstration of stimulation of NO production by VBPs in endothelial cells. Taken together with their localization in vascular endothelium of placenta, these observations suggest an important role for these VBPs in regulation of placental blood flow, in addition to transporting the respective vitamin ligand. FBP knockout is an embryo lethal condition and FBP null mice do not survive to full term. Administration of excess Folic acid does not completely reverse these effects, leading to development of abnormalities of heart and vasculature in the surviving embryos. The pregnancy terminating effects of neutralizing RCP and blocking FBP as in the knock-out mouse seems to involve compromise of placental blood supply by altering vascular tone, in addition to inhibiting proper vitamin transport to the developing fetus. Based on these observations, we speculate that function and/or level of these VBPs are altered in pre-eclampsia and abnormal fetal development.

The regional Bouguer gravity field for India has been obtained objectively by digitising the gravity data at 0.25 degrees interval and by subjecting it to two-dimensional symmetrical filtering with cutoff of 0.004 cycles/km (> 200 km). The data at continental edges were appended with co-sinusiods of appropriate wave number to produce a uniform rectangular grid. This process also avoids Gibb's phenomenon. The data set thus obtained was divided into four overlapping independent rectangles for the purpopse of filtering. This process also provided a check on the filtered values.The low-pass filtered (deeper?) and the residual (shallower?) maps so obtained are correlated with geology and tectonic regimes of the India subcontinent. The high gradients in the contours of the residual map and the gentle gradients in the regional map reflect the effects of shallower and mainly deeper structures, respectively.The regional field indicates: (1) a characteristic difference between the eastern and the western coasts; (2) a central high encompassing the Godavari graben and Satpura fold belt which bends syntaxially towards Aravalli trend; and (3) a NW-SE-trending low in southern peninsular India.The salient observations from the residual map are: (1) a clear rift-like structural signature with negative gravity values ir the centre flanked by positive gravity values over the Godavari graben; (2) the NE-SW Aravalli trend merges with the E-W Satpura trend in the south; (3) the gravity signature of the Narmada-Son lineament is not very conspicuous; and (4) an isolated patch of negative gravity values south of Bangalore is prominent.

Results of detailed microtopographical studies on prism faces of a large number of natural and hydrothermally grown quartz crystals are described, illustrated and discussed. In the light of these results distinction between prism faces of the two varieties of quartz is assessed. Horizontal striations, parallelogram shaped and low angle tetrahedral growth pyramids are reported as characteristic features on prism faces of natural quartz crystals, whereas hexagonal and square shaped pyramids are shown to be characteristic features on prism faces of cultured quartz crystals. Evidence of independent growth on prism faces of both the varieties of quartz crystals are given. A wide variety of growth forms, like oriented snail shaped hillocks, pentagonal elevations, rectangular spiral patterns, screw ledges, missile-like structures, influence of impurities on advancing growth fronts, microdiscs patterns and etch patterns due to chemical etching are explained.

A detailed study is made of surface structures of over four-hundred prism faces of cultured quartz. Growth spirals observed are illustrated. They have been examined with the help of a phase contrast microscope. Density of screw dislocations is found to vary between wide limits, being of the order of 104 cm−2 in most of the crowded regions. The role of spirals in the development of prism faces is discussed. Different types of interactions of spirals are illustrated. The origin of the formation of the spirals is also discussed. It is shown that the edges of the growth layers on the steeper sides of spiral growth pyramids constitute striations inclined at 45° to the edge between m(101̄0) and R(101̄1) faces.

Applying optical techniques, a study is carried out of the etch patterns produced, at room temperature, by diluted hydrofluoric acid and sodium hydroxide solution at 260°C, on partially cleaved rhombohedral cleavages of cultured quartz. Isolated and randomly distributed small pits are observed. The pits nucleated at the dislocations penetrated deeper in the body of the crystal on prolonged etching. Both the faces of cleaved thin flakes of the crystal have been etched in (1) alkali as well as (2) alkali and acid. One-to-one correspondence has been established in the number and positioning of the pits. Correspondence has also been established in the number and positioning of the isolated pits before and after polishing a cleavage. The curl bottomed nature of the pits has been attributed to the screw dislocations. The implications are discussed.

A detailed account of the optical and interferometric study of elevated disk patterns observed on prism faces of natural and cultured quartz crystals is given. Some of the disks observed have a spherical top surface while the others have a flat top surface. It is suggested that these disk patterns owe their origin to the protective action of micro-bubbles clinging to the crystal surfaces during the process of etching, towards the end of the crystal growth.

Employing precision optical techniques, a survey was made of rhombohodral faces of natural quartz. The gradient near the summit of several growth pyramids was found to be less than that away from it. The gradients in all the three directions are illustrated and interpreted. From the study of the slopes of the planes of the pyramids the direction of the flow of mother solution is deduced.

Several hundreds of natural quartz crystals obtained from overseas mines and from the Pannala Hills, Amreli District (Gujarat State, India) have been examined under a metallurgical phase contrast microscope. First evidence of screw dislocations and spirals on prism faces of natural quartz crystals are reported. The slip step observed on the prism face is shown to be parallel to the trace of a major rhombohedral plane, which is a direction of the ‘partial cleavage’. The increasing straight slope of the slip step emerging from the face has been attributed to the screw dislocation. Rectangular and irregular spirals are illustrated and interpreted as growth spirals.