We report large, non-saturating magnetoresistance (MR) of ∼140% in single layer chemical vapor deposition (CVD) graphene with an h-BN capping layer at room temperature at B = 9 T. Based on the ...classical model developed by Parish and Littlewood, our results show that the MR is proportional to the average mobility <μ > and decreases with increasing temperature. In contrast, in a large-area, extremely homogenous single layer epitaxial graphene (EG) device, the MR is saturating and is inversely proportional to <μ>, which is consistent with the finite resistance network picture. By comparing the results obtained from CVD graphene with an h-BN capping layer with those from the EG device, we show that the non-saturating linear characteristics come from multi-channel current paths in a two-dimensional plane due to the intrinsic grain boundaries and domains of CVD graphene by capping an h-BN layer that increase the <μ> of CVD graphene. Our results on CVD graphene with an h-BN capping layer pave the way for industrial schemes of graphene-based and air-stable magnetic field sensors with a linear, large response at room temperature.
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Release of dissolved organic matter (DOM) was studied on macroalga,
Ecklonia cava Kjellman, by
in situ field bag experiments, which were designed to keep the algal body under natural field condition, ...in Oura Bay, Shimoda, Izu Peninsula, Japan, from August 2003 to May 2005. The experiments were conducted 6 times in different seasons. The concentrations of dissolved organic carbon (DOC) in the experimental bag generally increased during the first 1–2 days, showing the release of DOC from algae. The daily release rates of DOC varied between 0.12 and 5.8 mgC per g (dry wt) of the algal blades per day. The seasonal variability of the DOC release rate was similar to those of the growth and the photosynthetic rates reported by the previous studies on
E. cava in the same location. The fractions of the DOC release of the net primary production accounted for 18–62%. These contributions are comparable to other macroalgae in the previous studies (27–43%) using other macroalgae. Analysis of organic composition of DOM using gas chromatography (neutral aldose composition) and spectrometry (UV-visible and fluorescence) indicates that
E. cava usually release extracellular products containing mucilaginous polysaccharides containing fucose as a main constituent and colored dissolved organic matter (CDOM). The release of these organic compounds is likely performed as the ordinary metabolism of brown algae. An exceptional release of a considerable amount of protein and carbohydrates mainly composed of mannose was found in June 2004, probably reflecting leakage of the intracellular material by an autolysis of the algal cells. The high DOM release rate in the present study suggests that macroalgae would be one of the important DOM producers in coastal regions.
The sucrose transporter gene family in rice Aoki, N. (CSIRO Plant Industry, Canberra (Australia)); Hirose, T; Scofield, G.N ...
Plant and cell physiology,
03/2003, Letnik:
44, Številka:
3
Journal Article
Recenzirano
In this paper we report the identification, cloning and expression analysis of four putative sucrose transporter (SUT) genes from rice, designated OsSUT2, 3, 4 and 5. Three of the four genes were ...identified through extensive searches of the recently published draft sequence of the rice genome. Along with the previously reported OsSUT1 we propose that these five genes comprise the rice SUT gene family. Complementary DNA clones were isolated for the four newly identified genes. The deduced proteins of all five SUT genes were predicted to contain 12 membrane-spanning helices and a domain highly conserved throughout all known plant SUTs, suggesting the four additional OsSUT genes encode functional SUTs. Reverse transcription-PCR analysis was performed in order to investigate the expression pattern of each member of the SUT family in rice. A differing but overlapping expression pattern was observed for each member of the SUT family at different stages through plant development. These results, together with the structural variations apparent from the deduced protein sequences, suggest that the five SUTs possess diverse roles in both sink and source tissues. We also discuss the classification and evolution of the rice SUT gene family, using a comparison of the gene structures and deduced amino acid sequences with other known plant SUT genes.
Prolactin (PRL) plays a central and crucial role in the regulation of milk protein gene expression in mammary epithelial cells. PRL binding to its cognate receptor leads to receptor dimerization and ...activation of the tyrosine kinase Janus kinase 2 (JAK2), associated with the membrane-proximal, intracellular domain of the receptor. In turn, JAK2 phosphorylates and activates STAT5, a member of the signal transducers and activators of transcription (STAT) family. We have recently reported that 16 different protein-tyrosine phosphatases (PTP) were expressed in lactating mouse mammary gland and mammary epithelial cells (Aoki, N., Kawamura, M., Yamaguchi-Aoki, Y., Ohira, S., and Matsuda, T. (1999) J. Biochem.(Tokyo) 125, 669–675). We investigated the involvement of each PTP in PRL signaling. Among the 12 phosphatases including SHP-2 examined, a cytosolic phosphatase PTP1B was found to specifically dephosphorylate STAT5a and STAT5b in transfected COS7 and in vitro. Nuclear translocation of STAT5a and STAT5b was largely inhibited upon overexpression of PTP1B. The PRL-dependent transcriptional activation of the β-casein gene promoter was also inhibited by PTP1B. Furthermore, retrovirus-mediated overexpression of PTP1B resulted in dephosphorylation of endogenous STAT5 and down-regulation of β-casein gene expression in mammary epithelial COMMA-1D cells when the cells were treated with lactogenic hormones. Endogenous tyrosine-phosphorylated STAT5 proteins in mammary epithelial COMMA-1D cells as well as tyrosine-phosphorylated STAT5a and STAT5b expressed in COS7 cells were co-precipitated by substrate-trapping mutants of recombinant PTP1B. These results strongly suggest that PTP1B dephosphorylates PRL-activated STAT5a and STAT5b, thereby negatively regulating PRL-mediated signaling pathway.
In northern Japan, Saccharina kelps are natural diets for sea urchins and are known to enhance sea urchin gonad size. However, little is known about the effects of the kelp diet on gonad quality and ...consistency among individuals. In the present study, Mesocentrotus nudus adults collected from a barren were cultured in a suspended cage from late February to early June 2014 in Shizugawa Bay, Miyagi Prefecture. They were fed stipes of Undaria pinnatifida for 56 d followed by fresh Saccharina japonica kelp for 42d. At the end of the culture period, gonad indices, gonad hardness, gonad color (L* (lightness), a* (redness), b* (yellowness)), free amino acid (FAA) contents in the gonads, and sensory qualities of the cultured sea urchins (EC) were measured and compared to those of the natural population from the barren (EB) and those from the Eisenia bicyclis kelp bed (EK) in the bay. Gonad index and L* values of EC urchins were higher than those of urchins from the barren at the start of culture (SCB). Total color (L*, a*, b*) of the gonads of EC and EK urchins were similar. Gonad hardness of EC and EK urchins was similar and lower than that of EB urchins, and the coefficients of variation of gonad index, color, and hardness were lower than those from the barren (SCB and EB). Sweet tasting alanine contents of the gonads of EC urchins were markedly higher than those of the gonads from the other urchin specimens. Bitter tasting FAA contents of the EC urchin gonads were higher than those of EK and EB urchins, although arginine and lysine contents were lower than those of EB urchins. Sensory scores of overall taste of EC urchins were higher than those of EB urchins and similar to EK urchins, possibly due to the increased alanine content. These results suggest that gonad size, color, hardness, taste, and consistency among individuals of M. nudus collected from barrens can be improved to reach levels similar to those of urchins from the E. bicyclis kelp bed by cage culture with short-term feeding of Saccharina kelps. Changes in gonad qualities seemed to be mainly due to S. japonica as the food source because hard U. pinnatifida stipes were rarely eaten and had markedly low protein content. Extension of cage culture duration with S. japonica feeding from spring to summer would increase gonad size and further improve gonad quality.
•Gonad color and hardness of sea urchin from a barren can be improved by cage culture and short-term feeding Saccharina kelp.•Very sweet tasting alanine content of the gonads increased markedly.•Consistency of the gonad qualities among individuals was also improved.
Heatwaves under global warming have negative impacts on ecosystem primary producers. This warming effect may be synergized or antagonized by local environments such as light and nutrient ...availability. However, little is known about the interactive effects of warming, irradiance, and nutrients on physiology of marine macroalgae, which are dominant in coastal ecosystems. The present study examined the combined effects of warming (23 and 26 °C), irradiance (30 and 150 µmol photon m−2 s−1), and nutrients (enriched and non-enriched) on specific growth rate (SGR) and biochemical compositions of the canopy-forming marine macroalga Sargassum fusiforme. The negative effect of warming on SGR and ratio of chlorophyll (Chl) c to Chl a was antagonized by decreased irradiance. Moreover, the negative effect of temperature elevation on carbon content was antagonized by nutrient enrichment. These results suggest that the effect of warming on the growth and carbon accumulation of this species can be mitigated by decreased irradiance and nutrient enrichment.
We show that a femtosecond laser enables us to produce true three-dimensional (3-D) microstructures embedded in a photosensitive glass, which has superior properties of transparency, hardness and ...chemical and thermal resistances. The photosensitivity arises from the cerium in the glass. After exposure to a focused laser beam, latent images are written. Modified regions are developed by a post-baking process and then preferentially etched away in a 10% dilute solution of hydrofluoric acid at room temperature. We have measured the critical dose for modification of the photosensitive glass, and fabricated 3-D microstructures with microcells and hollow microchannels embedded in the glass based on the critical dose.
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