CD57+/CD28- T cells in untreated hemato-oncological patients are expanded and display a Th1-type cytokine secretion profile, ex vivo cytolytic activity and enhanced tendency to apoptosis

Protopolystoma (Monogenea, Polystomatidae) is strictly specific to the anuran amphibian genus Xenopus. The host group is characterised by a polyploid series in which chromosome numbers reflect diploid, tetraploid, octoploid and dodecaploid constitutions; the series is considered to have evolved through interspecies hybridisation and genome duplication. This study correlates information on host evolutionary relationships with patterns of parasite speciation and host specificity. Protopolystoma is restricted to one subgenus (Xenopus) with multiples of 36 chromosomes, and is absent from the subgenus Silurana (with multiples of 20 chromosomes). Molecular, biochemical and karyotype evidence distinguishes three subgroups within Xenopus. Representative species from each subgroup, Xenopus muelleri, Xenopus fraseri and Xenopus laevis, have been examined for polystomatid infection. Two species of Protopolystoma occur in each of these host species. In X. muelleri, the two Protopolystoma species reflect parasite co-speciation corresponding with the divergence of two sibling host species. Xenopus fraseri and X. laevis (both with 2n = 36 chromosomes) are implicated in the hybrid origin of two octoploid species, Xenopus wittei and Xenopus vestitus (both 2n = 72). The relationships of the Protopolystoma species in these Xenopus taxa reflect this presumed ancestry. Xenopus wittei carries two species of Protopolystoma, one shared with X. fraseri and the other shared with X. laevis. Xenopus vestitus carries a single species of Protopolystoma which is shared with X. laevis but there is no "heirloom" which reflects its hybrid origin involving X. fraseri. In addition to these shared parasite species which may reflect shared host genes, X. fraseri and X. laevis each carry separate species-specific Protopolystoma which do not occur in other Xenopus species even where there is evidence of common genetic information (as in the allopolyploid wittei and vestitus). This case study may be interpreted as indicating a powerful influence of host genetic factors on susceptibility to infection, host-specificity, and parasite speciation.     

Survey of structural and electronic properties of C60 on close-packed metal surfaces

The adsorption of buckminsterfullerene (C₆₀) on metal surfaces has been investigated extensively for its unique geometric and electronic properties. The two-dimensional systems formed on surfaces allow studying in detail the interplay between bonding and electronic structures. Recent studies reveal that C₆₀ adsorption induces reconstruction of even the less-reactive close-packed metal surfaces. First-principles computations enable access to this important issue by providing not only detailed atomic structure but also electronic properties of the substrate–adsorbate interaction, which can be compared with various experimental techniques to determine and understand the interface structures. This review discusses in detail the ordered phases of C₆₀ monolayers on metal surfaces and the surface reconstruction induced by C₆₀ adsorption, with an emphasis on the different types of reconstruction resulting on close-packed metal surfaces. We show that the symmetry matching between C₆₀ molecules and metal surfaces determines the local adsorption configurations, while the size matching between C₆₀ molecules and the metal surface lattice determines the supercell sizes and shapes; importantly and uniquely for C₆₀, the number of surface metal atoms within one supercell determines the different types of reconstruction that can occur. The atomic structure at the molecule–metal interface is of crucial importance for the monolayer’s electronic and transport properties: these will also be discussed for the well-defined adsorption structures, especially from the perspective of tuning the electronic structure via C₆₀–metal interface reconstruction and via relative inter-C₆₀ orientations.     

Photoluminescence characterization of AlGaN-GaN pseudomorphic quantum wells and calculation of strain induced bandgap shifts

The low temperature (77 K) photoluminescence characteristics of Al _x Ga_1-x N-GaN strained layer quantum wells with differentx values grown by metalorganic chemical vapor deposition (MOCVD) were investigated. The photoluminescence spectra were useful in analyzing both quantum confinement effects and strain induced energy shifts. The strain induced shifts were found to be a strong function of aluminum compositionx. A model was developed to calculate the strain induced bandgap shifts atk = 0. The values predicted by this model which took into account the wurtzite crystal structure of the material system, were in good agreement with (i.e. within 2 meV of) the experimentally measured shifts.     

0.35 μm CMOS T/R Switch for 2.4 GHz Short Range Wireless Applications

This paper describes the design and implementation of a transmit/receive switch for 2.4 GHz ISM band applications. The T/R switch is implemented in a 0.35 m bulk CMOS process and it occupies 150 m · 170 m of die area. A parasitic MOSFET model including bulk resistance is used to optimize the physical dimensions of the transistors with regard to insertion loss and isolation. The measured insertion loss is 1.3 dB without port matching. Simulations using measured s-parameters indicate that an insertion loss of 0.8 dB can be obtained with a conjugate match. The measured isolation is 42 dB and the maximum transmit power is 16 dBm.     

Composition and protein quality of sweet lupin seed

The proportion of seed coats (hulls) of four varieties of sweet lupin seeds ranged from 19 to 25%. The amount of hull varied inversely with the weight of the seed, within each variety. Lupinus luteus cv Weiko III had 40.1% protein (dry basis); of 3 cultivars of L. angustifolius cv Uniharvest had the highest protein (36.2%), while cv Uniwhite had the lowest (28.6%). The protein content of dehulled lupins was about 20% higher than that of the whole seeds. L. angustifolius cv Uniwhite and L. luteus cv Weiko III were analysed for moisture, protein, lipid, ash, fibre, amino acids, carbohydrates, calcium, phosphorus, zinc, iron, copper and manganese. Whole seed, hulls and kernels were examined. Sulphur amino acids were limiting. The protein efficiency ratios of the two varieties, supplemented with methionine, were 2.40 and 2.56, respectively; these values increased by about 10% when the protein of the dehulled lupin seeds were tested. The requirement for added methionine for maximum p.e.r. was 0.65 g/kg diet. When dehulled lupin seed was steeped in water for a day and boiled and included in the diet of rats, slightly superior growth and p.e.r. resulted. The two varieties of dehulled lupin seeds effectively supplemented the protein of barley meal in the diet of rats, especially when methionine supplements were added, but were less efficient in supplemental value than was casein.     

Conditions affecting production of a protein isolate from lupin seed kernels

Conditions were investigated to determine the optimum processing parameters for preparation of a protein isolate from the ground, dehulled lupin seeds of Lupinus angustifolius. The extraction variables were: particle size (16–100 mesh); pH (2–11); extraction medium; solvent to lupin ratio (10:1 to 40:1); temperature (20–60^oC) and time (15–60 min). The isoelectric point of the lupin protein was found to be pH 4.5 with a protein solubility of greater than 90% above pH 8.0. Using 60–100 mesh ground lupin and extracting at pH 8.5 for 30 min, a protein isolate was obtained on acidification to pH 4.8 which was 89.4% protein compared to 34.0% protein for the original dehulled lupin. This protein isolate represented 19.8% of the starting material and 52% of the starting nitrogen. Similar results were also obtained when hexane defatted lupin was used. In this case the protein isolate had a protein content of 92.5%. The yield of protein isolate could be increased to 25.7% of the starting material if the extraction was repeated. The protein efficiency ratio for the protein isolate was 2.90 when supplemented with methionine.     

Optoelectronic switch with low holding power

A double heterostructure NpnP optoelectronic switching device with low holding power has been fabricated. In the static regime a holding power of 20 nW for a device area of 200 mu m*100 mu m was obtained. This value represents a reduction of four orders of magnitude in holding power compared to previous reported PnpN or PnN structures with equivalent device area. A higher optical sensitivity and a lower optical switching intensity is consequently obtained with these devices.<>     

Top-surface-emitting GaAs four-quantum-well lasers emitting at 0.85 mu m

Room temperature CW and pulsed lasing of top-surface emitting, vertical-cavity, GaAs quantum-well lasers was achieved at approximately 845 nm. The active gain medium was four 100 AA thick GaAs quantum wells. The whole structure was grown by molecular beam epitaxy. Deep H/sup +/-ion implantation followed by annealing as used to control a vertical profile of resistivity for an efficient current injection at the active region. The threshold current was 2.2 mA for CW and pulsed operation using 10 mu m diameter lasers. Differential quantum efficiency was about 20%. Minimum threshold current density per quantum well of 360 A/cm/sup 2/ was obtained.<>