Dielectric behaviour of glasses and glass ceramics in the system BaO-PbO-TiO2-B2O3-SiO2

Glasses with varying molar ratios of PbO/BaO in the system BaO-PbO-TiO₂-B₂O₃-SiO₂ were prepared keeping (BaO + PbO)/TiO₂ ratio equal to one. The glasses were ceramized by two-stage heat treatment. X-ray diffraction indicates that PbTiO₃ crystallizes in lead-rich glasses while BaTiO₃ precipitates in barium-rich compositions. Solid solution (Ba, Pb)TiO₃ does not seem to crystallize over the entire range of compositions. Simultaneous presence of PbO and BaO in the initial glass composition reduces the yield of ferroelectric phase. Dielectric properties have been interpreted in terms of microstructural features.     

Modeling Microwave Vacuum Drying Kinetics and Moisture Diffusivity of Carrot Slices

Carrot slices of 3.5 mm thickness were dried in a laboratory microwave vacuum dryer at five different microwave power density levels of 2, 4.66, 7.33, 10, and 12.66 W/g and at three vacuum chamber pressure levels of 6.66, 19.98, and 33.3 kPa to 4-6% d.b. moisture content. Inside the dryer the sample holding plate was rotated with the speed of 4 rpm for uniform microwaves application. The drying rates were increased with the increase in microwave power density at all pressure levels and the Page model was found to be the most suitable model to predict the drying behavior of carrot slices at all process conditions. The Page model drying rate constant (k, min^-1) showed high correlation with microwave power density at constant pressure by a power law equation and showed a logarithmic relationship with the microwave power density and pressure. Similar to the drying rate constant, the average moisture diffusivity at constant pressure was found to be function of microwave power density by power law equation as well as was also dependent on the power density and pressure by a logarithmic relationship.     

Establishment of human parotid pleomorphic adenoma cells in culture: morphological and biochemical characterization

This study reports the establishment of alpha-amylase-producing human parotid pleomorphic adenoma cell lines (2HP and 2HP1) which have been maintained in culture for over 1 yr. The procedures required preparation of cellular clumps from tumor tissue and plating them on plasma clot or precoated dishes. During the initial phase of growth they required modified MCDB-153 medium without serum. When cells showed signs of degeneration they were changed to MCDB-153 medium containing first 2% and then 10% heat inactivated fetal bovine serum. Although cells grew well in MCDB-153 containing 10% serum, the epithelial cell morphology was not distinct. Therefore, the growth and morphology of cells grown in MCDB-10% serum were compared with those in RPMI growth medium containing 10% fetal bovine serum and F12 containing 10% agammaglobulin newborn bovine serum. Although the growth of cells was a little slower in F12 medium than those in MCDB and RPMI, the epithelial cell morphology was maintained better than in other growth media. The cells of 2HP and 2HP1 produce low levels of alpha-amylase and relatively high levels of alpha-amylase mRNAs of 1176 and 702 bp and contain neurofilament-160, a neuronal-specific marker. The cells of 2HP1 are tumorigenic when tested in athymic mice, but the cells of 2HP are not. The establishment of amylase-producing human parotid adenoma cell lines of different characteristics in culture provides a new opportunity to study the mechanisms of differentiation and transformation, and regulation of alpha-amylase in these cells.     

Descriptive epidemiology of childhood cancers in Bangalore, India

While fairly complete and reliable incident data on childhood cancers are available from the registries in India, mortality and survival information is not. Information concerning the latter was obtained by the Bangalore cancer registry through active follow-up involving visits to homes of patients. Between 1982 and 1989, 617 cases of cancers in childhood were registered, giving an age-standardized incidence rate of 84.8 and 48.4 per million in male and female children, respectively. Active follow-up provided mortality/survival information in 532 or 86.2 percent of these cases. Overall, observed five-year survival was 36.8 percent (both genders combined) with a relative survival of 37.5 percent when childhood mortality in the general population was taken into account. The five-year relative survival was best for thyroid carcinoma (100 percent) followed by Hodgkin's disease (73 percent) and retinoblastoma (72.9 percent). Survival was comparatively low, being 9.9 percent in acute nonlymphatic leukemia and less than 20 percent in rhabdomyosarcoma and the category grouped as 'other malignant neoplasms.' Survival in Hodgkin's disease was influenced by clinical stage at presentation, but was not statistically significant possibly due to small numbers.     

Mobilization of lead by calcium versenate and dimercaptosuccinate in the rat

1. Calcium disodium ethylenediaminetetraacetate (CaNa2 EDTA) and meso-2,3-dimercaptosuccinic acid (DMSA) individually and in permutation-combination in various doses (0.1, 0.2 and 0.4 mmol/kg bodyweight) were investigated for their efficacy to mobilize lead from vital tissues into urine and faeces and to restore the lead-sensitive biochemical parameters in lead pre-exposed rats with a view to develop the most acceptable treatment regimen for lead poisoning with a minimal loss of endogenous essential elements. 2. The combined therapy was more effective than a single chelator treatment. 3. The combination of 0.2 mmol/kg CaNa2EDTA + 0.4 mmol/kg DMSA caused a lower depletion of zinc, calcium and iron but possessed almost equal capability to that of 0.4 mmol/kg CaNa2EDTA + 0.4 mmol/kg DMSA to produce urinary as well as faecal excretion of lead, to reduce the tissue burden of lead, including that of the brain, and to reverse lead-induced biochemical alterations. 4. The combination of 0.2 mmol/kg CaNa2EDTA + 0.4 mmol/kg DMSA has shown a definite improvement over previously reported combinations in terms of removal of lead from tissues, particularly the brain, restoration of urinary delta-aminolevulinic acid levels and a decrease in the loss of body zinc and is, therefore, recommended for the treatment of lead intoxication.     

An atomic model of the outer layer of the bluetongue virus core derived from X-ray crystallography and electron cryomicroscopy

BACKGROUND: Bluetongue virus (BTV), which belongs to the Reoviridae family and orbivirus genus, is a non-enveloped, icosahedral, double-stranded RNA virus. Several protein layers enclose its genome; upon cell entry the outer layer is stripped away leaving a core, the surface of which is composed of VP7. The structure of the trimeric VP7 molecule has previously been determined using X-ray crystallography. The articulated VP7 subunit consists of two domains, one which is largely alpha-helical and the other, smaller domain, is a beta barrel with jelly-roll topology. The relative orientations of these two domains vary in different crystal forms. The structure of VP7 and the organizations of 780 subunits of this molecule in the core of virus is central to the assembly and function of BTV. RESULTS: A 23 A resolution map of the core, determined using electron cryomicroscopy (cryoEM) data, reveals that the 260 trimers of VP7 are organized on a rather precise T = 13 laevo icosahedral lattice, in accordance with the theory of quasi-equivalence. The VP7 layer occupies a shell that is between 260 A and 345 A from the centre of the core. Below this radius (230-260 A) lies the T = 1 layer of 120 molecules of VP3. By fitting the X-ray structure of an individual VP7 trimer onto the cryoEM BTV core structure, we have generated an atomic model of the VP7 layer of BTV. This demonstrates that one of the molecular structures seen in crystals of the isolated VP7 corresponds to the in vivo conformation of the molecule in the core. CONCLUSIONS: The beta-barrel domains of VP7 are external to the core and interact with protein in the outer layer of the mature virion. The lower, alpha-helical domains of VP7 interact with VP3 molecules which form the inner layer of the BTV core. Adjacent VP7 trimer-trimer interactions in the T = 13 layer are mediated principally through well-defined regions in the broader lower domains, to form a structure that conforms well with that expected from the theory of quasi-equivalence with no significant conformational changes within the individual trimers. The VP3 layer determines the particle size and forms a rather smooth surface upon which the two-dimensional lattice of VP7 trimers is laid down.     

III–V super-lattice SPST/SPMT pin switches for THz communication: theoretical reliability and experimental feasibility studies

Microsystem Technologies - A physics-based Quantum-Modified CLassical Drift–Diffusion (QMCLDD) non-linear mathematical model has been developed for design and characterisation of GaN/AlGaN...     

Blind estimation of the PN sequence in lower SNR DS-SS signals with residual carrier

This paper presents a method of singular value decomposition (SVD) plus digital phase lock loop (DPLL) to solve the difficult problem of blind pseudo-noise (PN) sequence estimation in low signal to noise ratios (SNR) direct sequence spread spectrum (DS-SS, DS) signals with residual carrier. Of course, the method needs to know the parameters of DS signal, such as the period and code rate of PN sequence. Firstly, the received signal is sampled and divided into non-overlapping signal vectors according to a temporal window, whose duration is two periods of PN sequence. Then, an autocorrelation matrix is computed and accumulated by the signal vectors one by one. The PN sequence with residual carrier can be estimated by the principal eigenvector of this autocorrelation matrix. Furthermore, a DPLL is used to deal with the estimated PN sequence with residual carrier, it estimates and tracks the residual carrier, removes the residual carrier in the end. Theory analysis and computer simulation results show that this method can effectively realize the PN sequence estimation from the input DS signals with residual carrier in lower SNR.     

Register allocation for write activity minimization on non-volatile main memory for embedded systems

Non-volatile memories are good candidates for DRAM replacement as main memory in embedded systems and they have many desirable characteristics. Nevertheless, the disadvantages of non-volatile memory co-exist with its advantages. First, the lifetime of some of the non-volatile memories is limited by the number of erase operations. Second, read and write operations have asymmetric speed or power consumption in non-volatile memory. This paper focuses on the embedded systems using non-volatile memory as main memory. We propose register allocation technique with re-computation to reduce the number of store instructions. When non-volatile memory is applied as the main memory, reducing store instructions will reduce write activities on non-volatile memory. To re-compute the spills effectively during register allocation, a novel potential spill selection strategy is proposed. During this process, live range splitting is utilized to split certain long live ranges such that they are more likely to be assigned into registers. In addition, techniques for re-computation overhead reduction is proposed on systems with multiple functional units. With the proposed approach, the lifetime of non-volatile memory is extended accordingly. The experimental results demonstrate that the proposed technique can efficiently reduce the number of store instructions on systems with non-volatile memory by 33% on average.