Search

A high‐density surface‐wave plasma source is used to deposit hexagonal boron nitride (hBN) films in a gas mixture of He, H2, N2, Ar, and BF3 under a high ion flux condition using low‐energy ion irradiation. The ion energy is controlled between around zero and 100 eV by applying a negative or positive bias voltage to a substrate, while the ion flux is increased by locating a substrate upstream in the diffusive plasma. For ion energies above ∼37 eV, the structure of the films depends upon ion energy more than substrate temperature, typical of subplantation processes. As a result, the structural order and crystallinity of sp2‐bonded phase in the films characterized by Fourier transform infrared spectroscopy and X‐ray diffraction are increased with decreasing ion energy, while the mass density of the films characterized by X‐ray reflectivity is retained relatively high with a slight dependence upon ion energy. [ABSTRACT FROM AUTHOR]

Ovoviviparity and viviparity have evolved independently multiple times in animals. Although females exhibit extensive parental care of their eggs, (ovo)viviparity has only been reported in a few species of free-living, nonepizoic earwigs. In contrast, to date, all the studied members of families Arixeniidae and Hemimeridae, which live on mammals, are viviparous. We herein report ovoviviparity in the tropical earwig species, Spongovostox semiflavus (Bormans, 1894) (Forficuloidea: Spongiphoridae: Spongiphorinae). We observed that females of this species retain well-developed embryos within the ovaries and then lay them with complete egg envelopes just before hatching. An average of 9.4 embryos concurrently developed in a female's body. A similar condition has been reported for only one other species Marava arachidis (Yarsin, 1860), in the subfamily Spongiphorinae. Without additional mating, Spo. semiflavus females produced at least three clutches, consisting of an average of nine offspring within a period of 14-27 d. Both Spo. semiflavus and M. arachidis males are characterized by elongated male genitalia that are more than twice as long as their body lengths. Interestingly, elongated male genitalia are also present in the two other spongiphorids for which (ovo)viviparity has been reported. We discuss the causes of the potential convergence of the evolution of the male genital structure and the development of (ovo)viviparity in females. [ABSTRACT FROM AUTHOR]

The present study demonstrates for the first time, the development of mesoporous zirconium hydroxide with high CO2 capacity and sustainable adsorption–desorption performance within a broad range of pressures (100–3000 kPa). Mesoporous zirconium hydroxide with a high surface area of ∼400 m2 g−1 was prepared by a simple and easy-to-handle precipitation route. The prepared high surface area mesoporous zirconium hydroxide exhibited significantly higher CO2 adsorption uptake and working adsorption capacity on a volumetric basis within a wide range of operating pressures of 100–3000 kPa than commercially available zeolite 13X. Reversible CO2 desorption was easily achieved by a pressure swing at moderate temperatures (298.15 K). Additionally, the prepared mesoporous zirconium hydroxide was adequately stable and strong to effectuate CO2 capture over multiple adsorption–desorption cycles without major reductions in its CO2 adsorption capacity. Furthermore, the effect of co-adsorbed water on the CO2 adsorption properties of mesoporous zirconium hydroxide was investigated. In the presence of co-adsorbed water, mesoporous zirconium hydroxide displayed reversible CO2 adsorption–desorption behavior in contrast to zeolite 13X that exhibited negligible CO2 adsorption within the wide range of pressures examined. The present study demonstrates the potential of high surface area mesoporous zirconium hydroxide toward efficient CO2 capturing processes. [ABSTRACT FROM AUTHOR]

Sex allocation theories provide excellent opportunities to investigate not only the extent to which individuals' behaviour is adaptive, but also how they use relevant information for their decision-making. Here, we investigated whether female parasitoid wasps recognize the sex ratios of other females and adjust their laying sex ratios accordingly. Specifically, we tested the prediction of reciprocal cooperation over sex allocation. Theory predicts more female-biased (cooperative) sex ratios than in the interest of individual benefit, when a restricted number of ovipositing females interact for a long period and their offspring mate within the natal patch. This is because the female-biased sex ratio reduces competition for mates among the male offspring of the females and increases the overall reproductive productivity of the patch. In this case, females would be expected to respond to more even (noncooperative) sex ratios by others and to retaliate by also producing a less female-biased sex ratio to avoid exploitation by defectors. However, contrary to this prediction, our experiment using a sterile male technique showed that female Melittobia australica did not change their offspring sex ratios in response to the sex ratios produced by other females. This suggests that their extremely female-biased sex ratios cannot be explained by reciprocity. A meta-analysis of studies examining sex recognition ability in parasitoid wasps also did not support the predicted pattern of relevant sex ratio adjustment, suggesting that parasitoid females do not possess this ability. Here, we discuss the conditions necessary for the evolution of reciprocity linked to recognition ability. [ABSTRACT FROM AUTHOR]

The giant dielectric response in Cd-doped CaCu3Ti4O12 ceramics was studied over the temperature range from 40 K to 850 K. In all CaxCd1-xCu3Ti4O12 system, two broad dielectric dispersions around 150 K and 650 K and a dielectric anomaly at T1 were observed. The T1 decreases linearly with increasing Cd-molar ratio (x) from 733 K for CaCu3Ti4O12 to 632 K for CdCu3Ti4O12. CdCu3Ti4O12 exhibits ε ∼ 0.6 × 104 at room temperature and 1.4 × 104 at T1 (1 MHz). This evidence shows CdCu3Ti4O12 is still a member of high-dielectric materials in contrast to a previous work (ε ∼ 409 at 100 kHz). [ABSTRACT FROM AUTHOR]

Intermetallic alloys with B2 structure and dual-phase alloys of the B2 phase and an icosahedral (i-) phase have been produced, and their mechanical properties have been investigated. Vickers hardness measurements and compression experiments have shown that the dual-phase alloys have considerably higher strength than that of the B2 single-phase alloy up to a high temperature of around 750?K. The dual-phase alloys have also exhibited much better ductility than i-single-phase alloys. One possibility to be pointed out is that we can further design a high-strength and good-ductility alloy by tuning the volume fraction, size and morphology of the i-phase precipitates. [ABSTRACT FROM AUTHOR]

Forficulina, the largest suborder of Dermaptera (earwigs), has eight families. In five families (Pygidicranidae, Diplatyidae, Anisolabididae, Apachyidae, and Labiduridae), the males have two penises, whereas the males of the other three families (Spongiphoridae, Chelisochidae, and Forficulidae) have a single penis. Several cladograms have been proposed for Forficulina. However, those systems are constructed mainly from observations of male genital morphology and outstandingly inconsistent. This study reconstructed an earwig phylogeny with representatives of seven families (excluding Apachyidae) by using partial sequences of the mitochondrial 16S and nuclear 28S rRNA genes, sequences that are independent of genital evolution. To avoid difficulties caused by outgroup-rooting for a deep phylogeny, ingroup relationships were first established as unrooted trees based on the 16S, 28S, and combined data sets. The resulting affinities of the earwig families supported several superfamilies, such as Forficuloidea (single-penis families) and Pygidicranoidea (Pygidicranidae + Diplatyidae). Inclusion of the outgroup (Glylloblattodea and Blattodea) did not distort the established ingroup relationships. However, the root position varied according to the genes and outgroup taxa used. Kishino-Hasegawa tests based on the maximum likelihood criterion suggested that the common ancestor of contemporary Forficulina had twin penises, each with one gonopore. [ABSTRACT FROM AUTHOR]

Abstract We constructed a sex allocation model for local mate competition considering the asymmetry of competitive abilities among sons. This model assumes two females of a parasitoid wasp oviposit on the same host in sequential order. The evolutionarily stable strategy will be in either Stackelberg or Nash equilibrium, depending on whether the females can recognize their opponent's sex ratio or not, respectively. The Nash equilibrium predicts the second female produce more males than the first. If the second female is able to know and respond to the strategy of the first (a Stackelberg equilibrium), the first will decide an optimal sex ratio assuming that the second reply to it. Under such an assumption, our model predicts that not producing sons is adaptive for the second female when the sons she produces have low competitive ability. Males of parasitoid wasps Melittobia spp. are engaged in lethal male–male combat, indicating large asymmetry in mating success among sons. If females have the ability to recognize their opponent's sex ratio, our model suggests that the severe lethal male–male combat may be one factor explaining their extremely female-biased sex ratio that is unexplainable by pre-existent models. [ABSTRACT FROM AUTHOR]

The expression and localization of glial cell line-derived neurotrophic factor (GDNF) and its receptor GFRα1 in the testis were examined, because the blood-testis barrier is a well-known tissue barrier and we previously reported that GDNF reduced the endothelial permeability of the blood–brain barrier (BBB). Five minutes after intravenous injection of Evans blue (molecular weight, 960.6) or fluorescent dextran (molecular weight 10 000 and 70 000), Evans blue was observed outside microvessels of the testis, whereas the fluorescent dextran was not. Immunohistochemically, GDNF was detected in alpha-smooth muscle actin-positive cells around the seminiferous tubules and in microvessels. On the other hand, GFRα1 was detected in endothelial cells in the interstitial space, as well as in spermatocytes. Although occludin was positive in Sertoli cells and endothelium, claudin-5 was localized only in the endothelium of the microvessels. Thus, it became very clear that the microvessels in the testis possessed relatively impermeable tight junctions, and that the alpha-smooth muscle actin-positive cells secreted GDNF, which receptor was expressed in endothelial cells. Because this relation between GDNF and GFRα1 is similar to that observed in the BBB, we hypothesize that GDNF is a general regulator of tight junctions of the endothelium forming a blood–tissue barrier in a paracrine fashion. [ABSTRACT FROM AUTHOR]

An interpretation for the temperature dependence of the plastic flow stress of III-V compounds is presented, invoking only non-dissociated screw dislocations. With the aid of the Stillinger-Weber potential for the interatomic interaction, the Peierls potential of a non-dissociated screw dislocation is deduced in twodimensional space normal to the dislocation line. A saddle-point configuration and the formation energy of a kink pair are calculated in three-dimensional space. The relation obtained between the flow stress τ[sub c] and temperature T under a constant strain rate describes the experimental τ[sub c] T relation of III-V compound well: a strong T dependence at high τ[sub c] and low T, a stronger T dependence at low τ[sub c] and high T, and a plateau-like τ[sub c] at intermediate T. The hump in the τ[sub c] T relation is interpreted as a transition between different paths of the non-dissociated screw dislocation: a planar path and a zigzag path in the (111) plane. [ABSTRACT FROM AUTHOR]

Crude enzyme extract was obtained from a low-pH soil from a tea field by shaking with 0.1 M PO4 3– buffer (pH 7.0). Hydrolytic activity toward benzyloxycarbonyl- L-Phe- L-Leu (Z- L-Phe- L-Leu) and Z- L-Phe- L-Tyr- L-Leu showed two pH optima, at about pH 5 and 9, suggesting that the soil contained at least two protease components. The acid-type protease in the extract was assumed to be Ser-carboxypeptidase because phenylmethanesulphonyl fluoride and diisopropylphosphoro fluoridate inhibited its activity. Peptide bonds in the C-terminal residues of Leu-enkephalin and angiotensin I were split more by protease than those in the N-terminal residue. The apparent molecular weight of the acid-type protease was estimated to be 75 kDa by Sephadex G-100 gel filtration and the isoelectric point 4.4 by isoelectric focusing. A neutral-type protease in the extract was assumed to be a metallocarboxypeptidase because only o-phenanthrorine inhibited its activity. Peptide bonds in the C-terminal residues of Leu-enkephalin and angiotensin I were hydrolyzed to a greater extent than those in the N-terminal residues. The apparent molecular weight of the neutral-type protease was estimated to be 37 kDa and the isoelectric point 5.8, 8.0 and 9.4. The isoelectric point 9.4 fraction showed the highest relative activity. [ABSTRACT FROM AUTHOR]

The temperature dependence of the yield stress tau c of four bcc transition metals alpha-Fe, Nb, Mo and Ta, and an alkali metal K as well, follows a scaling relation of tau c/ tau P against kT/b3(tau PKT)1/2, where tau P is the Peierls stress, b the length of the Burgers vector and KT the line tension factor for a screw dislocation calculated for elastic anisotropy. The same relation seems to apply for the other three bcc transition metals V, Cr and W, suggesting its general applicability at least for low strain rates (about 10-4 s-1). The result implies that the plasticity of bcc metals is characterized by only one non-elastic parameter, the Peierls stress tau P. [ABSTRACT FROM AUTHOR]

Venous malformations in the posterior fossa are relatively rare. Although the introduction of CT and MRI has made them easier to detect, their treatment is still controversial. Based on our experience with six patients and a review of the literature, we have tried to establish guidelines for their treatment. Since they have a benign natural course and may provide venous drainage in the posterior fossa, venous malformation found incidentally, unruptured venous malformation with nonhaemorrhagic complications, and those accompanied by small intracerebellar haematoma of less than 2 cm in diameter due to their rupture, should be treated conservatively unless they are associated with a coexistent malformation. Venous malformation with intracerebellar haematoma larger than 3 cm or reexpansion of the haematoma due to rebleeding should be treated surgically by evacuation of the haematoma. Resection of venous malformations in the posterior fossa should be restricted to cases in which the malformation is small and does not serve as a functional venous drainage route. Radiation therapy, including the 'gammaknife', may be a treatment of choice in the future. [ABSTRACT FROM AUTHOR]

Examines the whole field spatial frequency analysis of double or multiple exposed particle image velocimetry (PIV) images. Role of spatial frequency filtering in reconstructing a velocity contour of map flows; Restriction of technique to simple flows; Application of wavelet analysis to the field spatial frequency analysis of PIV images.

The possible cancer promotion potential of local exposure to a pulse modulated 929.2 MHz electromagnetic near-field on chemically-initiated rat liver carcinogenesis was investigated employing a medium-term bioassay. A 929.2-MHz electromagnetic near-field of time division multiple access (TDMA) signal for PDC (Personal Digital Cellular, Japanese cellular telephone standard) system was directed to rats through a quarter-wavelength monopole antenna. Maximum local specific absorption rates (SARs) on temporal average were 7.2-6.6 W/kg within the whole body and 2.0-1.7 W/kg within the liver, which was the target organ. The whole-body average SARs on temporal average were 0.80-0.58 W/kg. Temporal peak SARs had three times these values due to the duty ratio of the PDC signal. Exposure was for 90 min a day, 5 days a week, over 6 weeks. The exposure apparatus was specially designed for this experiment, to allow exposure of the lateral mid-section of the rat body to the electromagnetic near-field. Male F344 rats, 6 week-old, were initially (at week 0) given a single dose of diethylnitrosamine (DEN, 200 mg/kg body wt, i.p.). At 2 weeks later, exposure (48 rats) or sham-exposure (48 rats) was started. The exposure of electromagnetic near-fields was performed using the exposure apparatus mentioned above. At week 3, all rats were subjected to a 2/3 partial hepatectomy. At week 8 (i.e. after 6 weeks exposure or sham-exposure), the experiment was terminated and all rats were killed. Carcinogenic potential was scored by comparing the numbers and areas of the induced glutathione S-transferase placental form (GST-P) positive foci in the livers of the exposed and sham-exposed rats. A further group of 24 animals, given only EN and partial hepatectomy, served as the controls. The numbers (no./cm2) of GST-P positive foci were 4.61 ± 1.77, 5.21 ± 1.92 (P <0.05, versus control) and 4.09 ± 1.47 and the areas (mm2 /cm2) were 0.30 ± 0.16, 0.36 ± 0.21 and 0.28 ± 0.15, for the exposed, sham-exposed and control groups, respectively. There were no significant differences between the exposed and sham-exposed groups. These findings clearly indicated that local body exposure to a 929.2-MHZ field, modulated in a PDC waveform, has no significant effect on rat liver carcinogenesis under the experimental conditions employed. [ABSTRACT FROM PUBLISHER]

The local electrical resistivities in deformed n-GaP have been measured by scanning spreading resistance microscopy (SSRM). The SSRM images show chainlike alignments of spots with high resistivity along the slip direction. These spots can be attributed to carrier-depletion around a charged dislocation. From the observed spot size, the line charge density of the dislocations has been estimated to be 0.4–0.9e/b, where b denotes the magnitude of the Burgers vector. The estimated value of line charge density has been discussed in relation with the dislocation core structure. [ABSTRACT FROM AUTHOR]