Planet Within a Planet: Rotation of the Inner Core of Earth

The time dependence of the orientation of Earth's inner core relative to the mantle was determined using a recently discovered 10-degree tilt in the axis of symmetry of the inner core's seismic-velocity anisotropy. Two methods of analyzing travel-time variations for rays traversing the inner core, on the basis of 29 years of data from the International Seismological Centre (1964-1992), reveal that the inner core appears to rotate about 3 degrees per year faster than the mantle. An anomalous variation in inner-core orientation from 1969 to 1973 coincides in time with a sudden change ("jerk") in the geomagnetic field.     

Protein-rich food mixtures for feeding the young in Egypt II-chemical and biological evaluation

Ten protein-rich baby food mixtures based on popular dishes were formulated mainly from vegetable sources. Such mixtures could be easily prepared at home from locally-produced crops available in markets at low prices. The nutritional studies undertaken on such mixtures, showed that they are rich in protein (17.7–23.2 g/100 g). They contain all the essential amino acids. Biological studies indicated that they are of high biological value and that they could be safely given to children. The costs of such food mixtures are within the reach of most Egyptians.     

Relative performance of two Nile tilapia ( Oreochromis niloticus Linnaeus) strains in Egypt: The Abbassa selection line and the Kafr El Sheikh commercial strain

The Abbassa selection line (developed by selective breeding) and the Kafr El Sheikh commercial strain (widely used in Egypt), both Oreochromis niloticus, were compared at two stocking densities (two and four fish m^?2). Harvest weight, length, depth, width and head length were recorded. The Abbassa line showed a superior harvest weight (28 per cent) over the Kafr El Sheikh strain. Males were heavier than females, but the between‐sex difference was greater in the commercial than in the Abbassa line (39 and 31 per cent respectively). Females in the Abbassa line grew almost as fast as males in the commercial line. Both strains grew faster at the lower density, and the percentage reduction in harvest weight at the higher density was about the same for both strains (27 per cent). The advantage of the Abbassa line was 28 per cent at both densities. Both strains had a similar survival rate (approximately 80 per cent) during the grow‐out period. We conclude that the Abbassa line is ready for release to the tilapia industry in Egypt. Further evidence is being sought in currently underway on‐farm evaluations. Measures should be taken to ensure the long‐term viability of the Abbassa line.     

Growth,biochemical variables,and zinc bioaccumulation in Nile tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> (L.) as affected by water-born zinc toxicity and exposure period

The present study was carried out to investigate the effect of sublethal zinc (Zn) concentrations on growth performance, biochemical variables, and Zn residues in various organs of Nile tilapia, Oreochromis niloticus (L.). Fish (25 ± 0.5 g) were exposed to 0.0, 3.5, or 7.0 mg Zn L^?1 for 1 or 6 weeks. Fish growth was significantly reduced with increasing Zn concentrations. However, fish exposed to 7.0 mg Zn L^?1 grew less quickly than those of the control group. Likewise, best feed intake and feed conversion ratio were obtained at the control group. Furthermore, glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and cortisol increased significantly with increasing Zn concentrations and exposure time, with maximal values in the 7.0 mg Zn L^?1 treatment after 6 weeks. Meanwhile, highest values of serum protein and lipids were obtained in the control fish reared for 6 week, whereas their lowest values were observed in fish exposed to 7.0 mg Zn L^?1 for 1 week. There was no significant change in whole-body moisture content of fish due to Zn exposure, although crude protein and total lipid contents decreased significantly with increasing Zn concentrations. In addition, Zn exposure increased total ash contents and Zn residues in different investigated fish organs. The Zn concentrations in all fish organs were time-dependant and the Zn residues after 1 week were found to follow the order of gills > liver > kidney > muscle, meanwhile after 6 weeks it followed the order of liver > kidney > gill > muscle. The present findings revealed that liver and kidney tissues are the prime sites of Zn bioaccumulation, while Zn load in the muscle was for low as compared to other organs.     

Toll‐like receptor and related cytokine mRNA expression in bovine corpora lutea during the oestrous cycle and pregnancy

Improving our understanding of the mechanisms controlling the corpus luteum (CL) and its role in regulating the reproductive cycle should lead to improvements in the sustainability of today's global animal industry. The corpus luteum (CL) is a transient endocrine organ composed of a heterogeneous mixture steroidogenic, endothelial and immune cells, and it is becoming clear that immune mechanisms play a key role in CL regulation especially in luteolysis. Toll‐like receptors (TLR) mediate innate immune mechanisms via the production of pro‐inflammatory cytokines, especially within various tissues, although the role of TLR within CL remains unknown. Thus, the objectives of this study were to characterize TLR mRNA expression in the CL during the oestrous cycle and in pregnancy (day 30–50), and to examine the role of TLR signalling in luteal cells. Corpora lutea were collected at various stages of the cycle and pregnancy and analysed for TLR and cytokine mRNA expression. In addition, luteal cells were cultured with the TLR4 ligand (lipopolysaccharide, LPS) for 24 h to evaluate the role of TLR4 in regulating luteal function. Toll‐like receptors 1, 2, 4, 6, tumour necrosis factor alpha (TNF), interferon gamma (IFN‐G), and interleukin (IL)‐12, mRNA expressions were greatest in regressing CL compared with earlier stages (p < .05), whereas no change was observed for IL‐6 mRNA expression. Cytokine mRNA expression in cultured luteal cells was not altered by LPS. Based on these data, one or more of the TLRs found within the CL may play a role in luteolysis, perhaps via pro‐inflammatory cytokine mRNA expression.     

Solution properties of single-walled carbon nanotubes

Naked metallic and semiconducting single-walled carbon nanotubes (SWNTs) were dissolved in organic solutions by derivatization with thionychloride and octadecylamine. Both ionic (charge transfer) and covalent solution-phase chemistry with concomitant modulation of the SWNT band structure were demonstrated. Solution-phase near-infrared spectroscopy was used to study the effects of chemical modifications on the band gaps of the SWNTs. Reaction of soluble SWNTs with dichlorocarbene led to functionalization of the nanotube walls.     

Design of a surface alloy catalyst for steam reforming

Detailed studies of elementary chemical processes on well-characterized single crystal surfaces have contributed substantially to the understanding of heterogeneous catalysis. Insight into the structure of surface alloys combined with an understanding of the relation between the surface composition and reactivity is shown to lead directly to new ideas for catalyst design. The feasibility of such an approach is illustrated by the synthesis, characterization, and tests of a high-surface area gold-nickel catalyst for steam reforming.     

Effect of Cold Hardening on Growth and Essential Oil Content of Mentha piperita L.

Divisions of running rhizomes of peppermint plants were planted in loamy clay soil in the experimental farm of National Research Centre, Dokki, Cairo, Egypt. After 21 days, the plants were exposed to low temperature 4, 7°C for 6, 9 and 12 days in controlled chamber before transplanting to large pots in winter season. Three cuttings were taken from the plants of different treatments during the season after 4, 7 and 10 months from transplanting. Representative samples of 6 replicates from each treatment were taken for the determination of vegetative growth and oil content in the leaves and branches.
The results obtained indicated that the highest fresh and dry weight of leaves and branches was recorded in the second cutting, however, it markedly decreased in the third one. The highest favourable effect of cold hardening on vegetative growth was observed at 4°C for 12 days exposure in the second cutting. The percentage of volatile oil in the leaves recorded the highest values in treatment of 7°C for 6 days in the second sampling date. Cold hardening either at 4°C or 7°C resulted in pronounced increase in the essential oil yield produced by the plant with the superiority of 4°C for 12 days which recorded the highest value.
It can be concluded from the obtained results that hardening peppermint plants with low temperature, particularly 4°C for 12 days before transplanting improved plant growth and considerably increased the volatile oil content in plant leaves and branches.     

Effects of cryoprotectants and cryoprotectant combinations on viability and maturation rates of Camelus dromedarius oocytes vitrified at germinal vesicle stage

Camel fertility faces many problems, which could be solved by assisted reproductive technologies (ARTs). We designed the experiment to explore the effect of different cryoprotectant concentrations and combinations on viability and maturation rates of vitrified/warmed camel oocytes. We collected ovaries directly after slaughtering from local abattoir and transported them to laboratory in a thermo‐flask containing normal physiological saline. We aspirated the oocytes from follicles, which is 2–8 mm in diameter, washed three times in TCM‐199 and then examined under stereo‐microscope for selection. We selected morphologically normal oocytes with an evenly granulated cytoplasm and a compact cumulus cell layer. We equilibrated morphologically normal oocytes in equilibration solution (ES), which is half concentration of vitrification one. After equilibration, We transported oocytes to vitrification solution using ethylene glycol (EG, 40%), dimethyl sulphoxide (DMSO, 40%) and EG 40% + DMSO 40%. The obtained results revealed that addition of EG 40% + DMSO 40% resulted in the best quality of vitrified/warmed oocytes, which is demonstrated by higher per cent survival rate (90.16%) and maturation rate (58.95%). While DMSO 40% resulted in 62.79% and 29.54%, respectively, EG 40% reported 86.11% and 53.47%, respectively. We could conclude that vitrification of immature camel oocytes by using 40% EG + 40% DMSO is suitable methods to limit drawbacks of vitrification methods, and we need further studies to assess the ability of in vitro‐produced blastocyst to develop in vivo and establish pregnancy after embryo transfer.