Trophoblast 'pseudo-tumorigenesis': Significance and contributory factors

Trophoblast cells of the human placenta proliferate, migrate, and invade the pregnant uterus and its vasculature in order to nourish the developing fetus, in a way that is imitated by malignant tumors. Many similarities exist between embryo implantation and the growth of cancer cells. We begin this article by reviewing decades of studies that have helped unearth the mechanisms that contribute to the tumor-like phenotype of human trophoblast cells. Interestingly, these attributes are only transient in nature, with stringent spatial and temporal confines. The importance of intrinsic molecular controls that effectively circumscribe the extent and duration of trophoblast incursion, becomes increasingly evident in abnormal pregnancies that are characterized by aberrant trophoblast proliferation/invasion. We summarize and discuss the significance of abnormalities in these regulatory mechanisms, and finally, speculate about the use of human trophoblastic cells as model systems for the study of a variety of cellular processes. While on one hand, human placental cells are bestowed with a capacity to proliferate indefinitely and invade extensively, on the other, these cells are also replete with mechanisms to regulate these tumor-like attributes and eventually progress to a senescent apoptotic state. This is therefore, a 'well-behaved' tumor. The comparison in the present review is between the invasive cytotrophoblastic cell type and the tumor cell type

A Computational Teddqae for Heat W a r h e to a Fast Movhg Hl(lf 80urce

The heat transfer in the two phase region in the study of melting and solidification of a surface layer by a moving heat source is studied.The transient problem is formulated using the enthalpy and temperature model and solved in an oblate spheroidal co-ordinate system using animplicit modified upwinding scheme in terms of non-dimensional nodal enthalpy and temperature. It is observed that the temperature gradient which controls the solidification rate, increases to a maximum initiallyand then decreases to zero. It is found that the solid-liquid interface velocity which is zero initially very quickly reaches to the velocity ofthe heat source, though the gradient ahead of the interface relaxes much more slowly

Mechanical behaviour of aluminium-lithium alloys

Aluminium-lithium alloys hold promise of providing a breakthrough response to the crying need for lightweight alloys for use as structurals in aerospace applications. Considerable worldwide research has gone into developing a range of these alloys over the last three decades. As a result, substantial understanding has been developed of the microstructure-based micromechanisms of strengthening, of fatigue and fracture as well as of anisotropy in mechanical properties. However, these alloys have not yet greatly displaced the conventionally used denser Al alloys on account of their poorer ductility, fracture toughness and low cycle fatigue resistance. This review aims to summarise the work pertaining to study of structure and mechanical properties with a view to indicate the directions that have been and can be pursued to overcome property limitations

Effects of ICI 182780 on estrogen receptor expression, fluid absorption and sperm motility in the epididymis of the bonnet monkey

BACKGROUND: The importance of estrogen in regulation of fluid absorption and sperm maturation in the rodent epididymis has been established from studies on estrogen receptor-alpha knockout mice. However, functional studies on the role of estrogen in primate epididymis have been few. The main objective of this study was therefore to extend these observations and systematically analyze the presence and function of estrogen receptors in modulating the function of the primate epididymis, using the bonnet monkey (Macaca radiata) as a model system. METHODS: A steroidal estrogen receptor (ER) antagonist, ICI 182780 (ICI), was administered to adult male bonnet monkeys via mini-osmotic pumps for a duration of 30 to 180 days. The expression of key estrogen-regulated genes (ER-alpha, Na-K ATPase alpha-1 and Aquaporin-1) was examined at specific time points. Further, the effect of ICI in modulating fluid reabsorption in efferent ductules was monitored, and critical sperm-maturation parameters were also analyzed. RESULTS: Our studies in the bonnet monkey revealed that both ER-alpha and ER-beta were expressed in all the three regions of the epididymis. We observed an increase in ER-alpha mRNA and protein in the caput of ICI-treated monkeys. Steady state mRNA levels of the water-channel protein, Aquaporin-1, was significantly lower in the caput of ICI-treated monkeys compared to controls, whereas the mRNA levels of Na-K ATPase alpha-1 remained unchanged. In vitro incubation of efferent ductules with ICI resulted in two-fold increase in tubular diameter, indicating affected fluid reabsorption capacity. Furthermore, sperm from ICI-treated monkeys were immotile. CONCLUSION: Taken together, our results point to an integral role for estrogen in modulating the functions of the bonnet monkey epididymis. This study also demonstrates possible differences in the epididymal physiology of rodents and non-human primates, and thus underscores the significance of reports such as these, that examine the physiology of non-human primates (as opposed to rodents), in an attempt to understand similar events in the human

SWaP Optimised Parameter Extraction of Radar Signals for Space Electronic Intelligence Application

Space-based electronic intelligence system provides wide coverage and unrestricted access to adversary radar signals. These systems play a vital role in strategic intelligence gathering for assessing electronic order of battle. These systems need to be SWaP optimized with highly efficient algorithms to extract accurate radar parameters. The realization of such a system is a persistent challenge due to the limited availability of space graded components and associated tools. Towards this, the paper deliberates upon various signal processing algorithms to achieve highly accurate direction-of-arrival (DOA), high-frequency resolution and precise timing information for pulse width and pulse repetition frequency extraction. All the proposed algorithms have been implemented, ported and tested on Xilinx Kintex Ultra Scale FPGA KU060 and being evaluated in the radiation setups to establish the performance. High DOA accuracy and frequency accuracy of the order of 0.3 degree and 0.64 MHz respectively have been achieved

An 18 mer sequence in a rat 1.3 kbp EcoRI repeat detects genetic polymorphism in humans

DNA fingerprinting involves the typing of an individual's DNA content to produce somatically stable,individual-specific DNA fingerprints. This technique often uses hypervariable minisatellite (HVMS) sequences as the fingerprinting probe and has found extensive use in several disciplines. Recently, we sequenced a 1.3 kbp EcoRI repetitive DNA fragment, shown to harbour the meiotic DNA repair site(s) of rat pachytene spermatocytes. This 1.3 kbp clone contained four sequences sharing high homology to the various HVMS sequences reported in the literature. Here we show that one of the sequences can indeed detect polymorphism in human individuals and can be used for DNA fingerprinting

Damage localization of closing cracks using a signal decomposition technique

Fatigue cracks are a common occurrence in engineering structures subjected to dynamic loading and need to identify at its earliest stage before it leads to catastrophic failure. The presence of fatigue-breathing crack or closing cracks is usually characterised by the presence of sub, super-harmonics, and inter-modulation in the response of the structure subjected to harmonic excitation. It should be mentioned here that the amplitude of nonlinear harmonics are of very less order in magnitude when compared to linear or excitation component. Further, these nonlinear components often get buried in noise as both are having matched (low) energy levels. The present work attempts to decompose the acceleration time history response using singular spectrum analysis and propose a strategy to extract the nonlinear components from the residual noisy time history component. A new damage index based on these extracted nonlinear features is also proposed for closing crack localization. The effectiveness of the proposed closing crack localization approach is illustrated using detailed numerical studies and validated with lab level experimentation on the simple beam-like structure. It can be concluded from the investigations that the proposed signal decomposition based damage localization technique can detect and locate more than one crack present in the structure

Enantioselective synthesis of (R)-(+)-safrole oxide

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