http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Steinhoff, A. (검색결과 6 건)
- 무료
- 기관 내 무료
- 유료
-
Efficient Excitonic Photoluminescence in Direct and Indirect Band Gap Monolayer MoS<sub>2</sub>
Steinhoff, A.,Kim, J.-H.,Jahnke, F.,Rö,sner, M.,Kim, D.-S.,Lee, C.,Han, G. H.,Jeong, M. S.,Wehling, T. O.,Gies, C. American Chemical Society 2015 NANO LETTERS Vol.15 No.10
<P>We discuss the photoluminescence (PL) of semiconducting transition metal dichalcogenides on the basis of experiments and a microscopic theory. The latter connects ab initio calculations of the single-particle states and Coulomb matrix elements with a many-body description of optical emission spectra. For monolayer MoS<SUB>2</SUB>, we study the PL efficiency at the excitonic A and B transitions in terms of carrier populations in the band structure and provide a quantitative comparison to an (In)GaAs quantum well-structure. Suppression and enhancement of PL under biaxial strain is quantified in terms of changes in the local extrema of the conduction and valence bands. The large exciton binding energy in MoS<SUB>2</SUB> enables two distinctly different excitation methods: above-band gap excitation and quasi-resonant excitation of excitonic resonances below the single-particle band gap. The latter case creates a nonequilibrium distribution of carriers predominantly in the K-valleys, which leads to strong emission from the A-exciton transition and a visible B-peak even if the band gap is indirect. For above-band gap excitation, we predict a strongly reduced emission intensity at comparable carrier densities and the absence of B-exciton emission. The results agree well with PL measurements performed on monolayer MoS<SUB>2</SUB> at excitation wavelengths of 405 nm (above) and 532 nm (below the band gap).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-10/acs.nanolett.5b02719/production/images/medium/nl-2015-02719d_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl5b02719'>ACS Electronic Supporting Info</A></P>
-
-
-
Protease-Activated Receptors-2: Role in Skin Biology and Barrier Function
Ferda Cevikbas,Akihiko Ikoma,Martin Steinhoff 한국피부장벽학회 2009 한국피부장벽학회지 Vol.11 No.2
Proteinases play an essential role in skin homeostasis and various disease states. This is -at least in part-mediated via activation of proteinase-activated receptors (PARs). These are G-protein-coupled receptors with seven transmembrane domains that are activated by specific proteolytic cleavage of the extracellular N-terminus. To date, four PARs are cloned and characterized (PAR1-4). They are stimulated by a variety of serine proteinases. PAR1, PAR3 and PAR4 are cleaved by thrombin, for example. Both PAR1 and PAR4 can be activated by trypsin as well; PAR4 can be also activated by cathepsin G and PAR1 can also be triggered by matrix metalloproteinase-1. PAR2 can be activated by a variety of endogenous serine proteinases like tryptase, matriptase or certain kallikreins. The latter have an important impact in the regulation of skin barrier and may thus be involved in its malfunction during disease state. This receptor can additionally be stimulated by various exogenous proteinases produced by pathogenic organisms like mites, bacteria or fungi, which are capable of modulating epidermal barrier function. It can also be inactivated by certain proteinases which may be of pathophysiological releavance; these mechanisms, however, are poorly understood as of yet. PAR2 is expressed by many cell types present in the skin including keratinocytes in the higher epidermal layers, fibroblasts, endothelial cells as well as by sensory neurons. Moreover, functional PAR2 is expressed by cells crucially involved in innate and adaptive immunity such as eosinophils, neutrophils, monocytes, macrophages, dendritic cells, mast cells and T cells, which may affect skin barrier function during inflammation and immune responses. Activation of the receptor leads to the production of various cytokines, chemokines or growth factors thereby modulating skin homeostasis, barrier function, immune and inflammatory responses as well as tumor surveillance. Thus, aiming at proteases and PARs may be beneficial for the treatrment of various skin diseases and barrier dysfunction.
-
Delva, Jorge,Grogan-Kaylor, Andrew,Steinhoff, Emily,Shin, Dong-Eok,Siefert, Kristine The Korean Society for Preventive Medicine 2007 예방의학회지 Vol.40 No.2
Objectives : This study characterized the extent to which youth depressive symptoms, parental alcohol problems, and parental drinking account for differences in alcohol-related problems among a large sample of adolescent females. Methods : The stratified sample consists of 2077 adolescent females from twelve female-only high schools located in a large metropolitan city in the Republic of Korea. Students completed a questionnaire about alcohol use and alcohol problems, their parents' alcohol problems, and a number of risk and protective factors. Data were analyzed using tobit regression analyses to better characterize the associations among variables. Results : Almost two-thirds of students who consume alcohol had experienced at least one to two alcohol-related problems in their lives and 54.6% reported at least one current symptom of depression, with nearly one-third reporting two depressive symptoms. Two-thirds of the students indicated that at least one parent had an alcohol-related problem, and that approximately 29% had experienced several problems. Results of tobit regression analyses indicate that youth alcohol-related problems are positively associated with depressive symptoms (p<0.01) and parent drinking problems (p<0.05). Parental drinking is no longer significant when the variable parental attention is added to the model. Decomposition of the tobit parameters shows that for every unit of increase in depressive symptoms and in parent drinking problems, the probability of a youth experiencing alcohol problems increases by 6% and 1%, respectively. For every unit of increase in parental attention, the probability of youth experiencing drinking problems decreases by 5%. Conclusions : This study presents evidence that alcohol-related problems and depressive symptoms are highly prevalent among adolescent females. Although a comprehensive public health approach is needed to address drinking and mental health problems, different interventions are needed to target factors associated with initiation of alcohol problems and those associated with increased alcohol problems among those who already began experiencing such problems.
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
