http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Monika Kordowska-Wiater,Urszula Lisiecka,Krzysztof Kostro 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.5
Arabitol is used in the food industry as a lowcalorie sweetener. It is produced by yeasts during the biotransformation process of L-arabinose. Genome shuffling was performed in Candida parapsilosis DSM 70125, an efficient producer of arabitol, to obtain fusants with improved arabitol production ability. Four mutants from the parental library were used for the first round of genome shuffling. The best fusants, GSI-1 and GSI-10A, were subjected to a second round of genome shuffling. Finally, two fusants, GSII-3 and GSII-16, produced concentrations of arabitol that were 50% higher than that of the wild-type strain during selection culture. Under the optimal conditions established for C. parapsilosis, the two fusants produced 11.83 and 11.75 g/L of arabitol and were approximately 15–16% more efficient than the wild-type strain. Flow cytometry analysis showed that the ploidy of the new strains did not change.
Magnetoresistance of Iodine-Doped CdMnTe/CdMgTe Spin Quantum Wells
V. Kolkovsky,M. Wiater,T. Wojtowicz,G. Karczewski,J. Jaroszynski 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
Single Cd1-xMnxTe quantum wells embedded in nonmagnetic Cd1-MgyTe barriers were grown by using molecular beam epitaxy (MBE). The Cd1-xMnxTenCd1-MgyTe structures were modulation doped by using iodine donors. The manganese (x) and the magnesium (y) contents were carefully adjusted to obtain the same values of the energy band gaps in both materials. A composition adjustment was achieved based on photoluminescence measurements. The magnetoresistance measurements were carried out in the temperature range from 1.6 K to 300 K and at magnetic fields up to 9 T. The analysis of the Hall effect measurements indicated that increasing of the magnetic eld caused the formation of a quantum well in the conduction band of the magnetic Cd1-MnxTe layer. This effect caused a transfer of quasi-free electrons from a 3D conducting channel located in the non-magnetic Cd1-MgyTe barriers to a magnetically-induced 2D quantum well. As expected, the electrons localized in the 2D conduction channel were highly mobile, which was manifested by the appearance of Shubnikov-de Haas oscillations.
Colossal Magnetoresistance in (Cd,Mn)Te heterostructures
T. Andrearczyk,W. Zaleszczyk,M. Wiater,T. Wojtowicz,M. Sawicki,G. Karczewski,T. Dietl,Dragana Popovic,J. Jaroszynski 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1
We report on magnetotransport in diluted magnetic 2D modulation doped (Cd,Mn)Te quantum wells and 3D bulk (Cd,Mn)Se samples. The application of magnetic elds reveals features commonly observed in colossal magnetoresistant (CMR) materials, such as a strong negative magnetoresistance and dramatic and nonmonotonic changes in the zero-eld resistance, which coincide with the fer- romagnetic ordering. These phenomena are present near the metal-insulator transition (MIT), yet another common property of CMR systems. Most likely, the observed CMR-like features re ect nanoscale phase separation of the electron uid and the emergence of ferromagnetic clusters in an intermediate density region. Our results suggest that the clustering around the MIT is ubiquitous not only in CMR manganites and underdoped cuprates but also in disordered semiconductors. We report on magnetotransport in diluted magnetic 2D modulation doped (Cd,Mn)Te quantum wells and 3D bulk (Cd,Mn)Se samples. The application of magnetic elds reveals features commonly observed in colossal magnetoresistant (CMR) materials, such as a strong negative magnetoresistance and dramatic and nonmonotonic changes in the zero-eld resistance, which coincide with the fer- romagnetic ordering. These phenomena are present near the metal-insulator transition (MIT), yet another common property of CMR systems. Most likely, the observed CMR-like features re ect nanoscale phase separation of the electron uid and the emergence of ferromagnetic clusters in an intermediate density region. Our results suggest that the clustering around the MIT is ubiquitous not only in CMR manganites and underdoped cuprates but also in disordered semiconductors.
Artur Trajnerowicz,Andrzej Golnik,Piotr Kossacki,Wojciech Pacuski,Witold Bardyszewski,Maciej Wiater,Grzegorz Karczewski,Tomasz Wojtowicz 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
Systematic studies of excitonic lines in the strong excitation regime were carried out by using a pump-probe method. Several samples containing quantum wells with different well widths (from 80 Å to 160 Å) were investigated. Most of the quantum wells were intentionally undoped but contained a 2D gas of free holes. The density of the free holes could be varied by changing the intensity of additional illumination. After resonant excitation of the heavy-hole exciton ground state by using an intense pump pulse we observed changes in the heavy- and the light-hole exciton lines. The resonant creation of a high population of e1hh1 excitons caused energetic blue shifts of the e1lh1 excitons. The blue shift in the experiment with opposite circularly-polarized pump and probe pulses could be explained as an interaction of electrons of the same spin bounded into the e1hh1 and the e1lh1 excitons. Model calculations of absorption showed qualitative agreement with the experimental data.
Modulation of Quantum Well Optical Properties by Illumination above the Barrier Bandgap
D. Wolverson,A. V. Koudinov,Yu. G. Kusrayev,L. C. Smith,J. J. Davies,M. Wiater,G. Karczewski,T. Wojtowicz 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
The spin flip Raman scattering signals associated with the Mn2+ 3d5 electrons in a range of CdTe-based dilute magnetic semiconductor quantum well structures is shown to be sensitive to even very weak above-barrier illumination, as are the quantum-well photoluminescence from exciton and trion recombination and acoustic phonon Raman scattering signals excited in resonance with the quantum well. This surprising degree of sensitivity is discussed in terms of the modulation of the carrier densities in the quantum wells, leading to a modulation of the resonant intermediate state for Raman scattering and, therefore, of the scattering cross section. Depending on the majority intrinsic carrier type in the quantum wells, we show that either enhancing or quenching of the Raman signals can result.
cAMP-inducible coactivator CRTC3 attenuates brown adipose tissue thermogenesis
Yoon, Young-Sil,Tsai, Wen-Wei,Van de Velde, Sam,Chen, Zhijiang,Lee, Kuo-Fen,Morgan, Donald A.,Rahmouni, Kamal,Matsumura, Shigenobu,Wiater, Ezra,Song, Youngsup,Montminy, Marc National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.23
<P>In response to cold exposure, placental mammals maintain body temperature by increasing sympathetic nerve activity in brown adipose tissue (BAT). Triggering of beta-adrenergic receptors on brown adipocytes stimulates thermogenesis via induction of the cAMP/PKA pathway. Although cAMP response element-binding protein (CREB) and its coactivators-the cAMP-regulated transcriptional coactivators (CRTCs)-mediate transcriptional effects of cAMP in most tissues, other transcription factors such as ATF2 appear critical for induction of thermogenic genes by cAMP in BAT. Brown adipocytes arise from Myf5-positive mesenchymal cells under the control of PRDM16, a coactivator that concurrently represses differentiation along the skeletal muscle lineage. Here, we show that the CREB coactivator CRTC3 is part of an inhibitory feedback pathway that antagonizes PRDM16-dependent differentiation. Mice with a knockout of CRTC3 in BAT (BKO) have increased cold tolerance and reduced adiposity, whereas mice overexpressing constitutively active CRTC3 in adipose tissue are more cold sensitive and have greater fat mass. CRTC3 reduced sympathetic nerve activity in BAT by up-regulating the expression of miR-206, a microRNA that promotes differentiation along the myogenic lineage and that we show here decreases the expression of VEGFA and neurotrophins critical for BAT innervation and vascularization. Sympathetic nerve activity to BAT was enhanced in BKO mice, leading to increases in catecholamine signaling that stimulated energy expenditure. As reexpression of miR-206 in BAT from BKO mice reversed the salutary effects of CRTC3 depletion on cold tolerance, our studies suggest that small-molecule inhibitors against this coactivator may provide therapeutic benefit to overweight individuals.</P>