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Polarity,intramolecular charge transfer,and hydrogen bond comediated solvent effects on the optical properties of graphene quantum dots

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Nano Research 2023年第1期16卷 45-52页

作者： Yalei Hu Christof Neumann Lena Scholtz Andrey Turchanin Ute Resch-Genger siegfried Eigler Institute of Chemistry and Biochemistry Freie Universität BerlinTakustraße 314195 BerlinGermany Institute of Physical Chemistry and Abbe Center of Photonics Friedrich Schiller University JenaLessingstraße 1007743 JenaGermany Federal Institute for Materials Research and Testing(BAM) Division BiophotonicsRichard Willstätter Straße 1112489 BerlinGermany

Graphene quantum dots(GQDs)have attracted increasing attention due to their favorable optical properties and have been widely used,e.g.,in the biomedical ***,the properties related to the chemical structure of GQDs,resulting in solventdependent optical properties,still remain ***,we present the synthesis of long-wavelength emitting GQDs with a size of about 3.6 nm via a solvothermal method using oxo-functionalized graphene(oxo-G)and p-phenylenediamine as precursors and their structural and surface chemical analysis by transmission electron and atomic force microscopy(TEM;AFM)as well as Fourier-transform infrared,Raman,and X-ray photoelectron spectroscopy(FTIR;Raman;XPS).Subsequently,the influence of solvent polarity and proticity on the optical properties of the as-prepared GQDs bearing–OH,–NH_(2),–COOH and pyridine surface groups was *** on the results of the absorption and fluorescence(FL)studies,a possible luminescence mechanism is *** observed solvent-induced changes in the spectral position of the FL maximum,FL quantum yield,and FL decay kinetics in protic and aprotic solvents of low and high polarity are ascribed to a combination of polarity effects,intramolecular charge transfer(ICT)processes,and hydrogen ***,the potential of GQDs for the optical sensing of trace amount of water was *** results of our systematic spectroscopic study will promote the rational design of GQDs and shed more light on the FL mechanism of carbon-based fluorescent nanomaterials.

关键词： graphene quantum dots(GQDs) polarity intramolecular charge transfer(ICT) hydrogen bond optical properties

MEASUREMENT OF ADHESION FORCES IN AIR WITH THE VIBRATION METHOD

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China Particuology 2005年第1期3卷 3-9页

作者： siegfried Ripperger Konrad Hein Lehrstuhl für Mechanische Verfahrenstechnik Technische Universit(a|¨)t Kaiserslautern67653 Kaiserslautern Germany Lehrstuhl für Mechanische Verfahrenstechnik Technische Universit(a|¨)t Dresden 01062 Dresden Germany

The vibration method represents a practical method for the measurement of adhesion forces and adhesion force distributions. This method causes sinusoidally alternating stresses and yields detachment and contact forces between particles and substrate of the same order of magnitude. Alternating contact forces of the vibration method can cause an adhesion force intensification through flattening of asperities. The measuring principle of the vibration method and the analysis of experimental results are described in the article. Normal adhesion forces (pull-off forces) are measured using the vibration method and the colloidal probe technique. The results of both methods show good agreement for small particle sizes. The influence of the detachment force direction is shown by comparing tangential and normal adhesion forces measured using particle reentrainment in a turbulent air flow and the vibration method, respectively. The surface roughness of the substrate and the relative humidity are shown to significantly influence the measured adhesion forces. For the calculation of the adhesion forces, an approach by Rabinovich was combined with approximations of plastic micro asperity flattening. The Rabinovich approach accounts for roughness effects on the van der Waals force by incorporating the rms roughness of the interacting surfaces, rms-values of the particles and substrates were measured with atomic force microscopy at different scanning areas.

关键词： adhesion force vibration method roughness

The past,present,and future of the Siberian Grouse(Falcipennis falcipennis)under glacial oscillations and global warming

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Avian Research 2022年第1期13卷 57-63页

作者： Wendong Xie Kai Song siegfried Klaus Jon E.Swenson Yue-Hua Sun Key Laboratory of Animal Ecology and Conservation Biology Institute of ZoologyChinese Academy of SciencesBeijing100101China College of Life Science Hebei UniversityBaoding071002China Lindenhöhe 5 D-07749JenaGermany Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life SciencesPO Box 5003NO-1432ÅsNorway

Global climate change has a significant effect on species,as environment conditions change,causing many species'distributions to *** the last three million years,the earth has experienced glacial oscillations,forcing some species to survive in ice-free refugia during glacial periods and then disperse *** this study,by assessing the potential distribution of Siberian Grouse(Falcipennis falcipennis),we used Global Circular Models and Representative Concentration Pathways to model their pattern of range changes during glacial oscillations and the potential impact of present global *** used 158 location records of Siberian Grouse to generate a full climate model using 19 bioclimate variables in *** discarded variables with a correlation coefficient larger than 0.8 and relatively lower modeling contributions between each pair of correlated *** the remaining variables,we created a normally uncorrelated simple climate model to predict the possible distribution of Siberian Grouse from the most recent Ice Age to present and to *** we added geographical data and the human interference index to construct a multiple factor full model to evaluate which were important in explaining the distribution of Siberian *** Total Suitability Zone(P≥0.33)of Siberian Grouse is about 243,000km^(2) and the Maximum Suitability Zone(P≥0.66)is 36,000km^(2) and is confined to the Russian Far *** habitat modeling suggested that annual precipitation,annual mean temperature,and the distance from lakes are the most explanatory variables for the current distribution of Siberian *** distribution center moved to the southeast during the Last Glacial Maximum and spread back to the northwest after the ice melted and temperatures *** total area range of Siberian Grouse experienced a dramatic loss during the Last Glacial *** warming is presently forcing the Siberian Grouse to migrate northward with a contraction of

关键词： Climate change Falcipennis falcipennis Ice age refugia Last glacial maximum

Differential retention of lymph-borne CD8 memory T cell subsets in the subcapsular sinus of resting and inflamed lymph nodes

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Cellular & Molecular Immunology 2021年第5期18卷 1317-1319页

作者： Ginka Nikolova siegfried Weiss Berislav Bosnjak Reinhold Förster Institute of Immunology Hannover Medical School30625HannoverGermany Cluster of Excellence RESIST(EXC 2155) Hannover Medical School30625HannoverGermany

Immunological memory represents the ability of specific immune cells to recall an encounter with a cognate *** results in an immediate response upon a second exposure to the same infectious ***,conventional memory T cells are generated after encountering specific foreign *** contrast,a group of innate memory T cells develops without initial exposure to foreign antigen that specifically binds to a cognate T cell receptor.1 These naturally occurring memory-like T cells,also known as“virtual”memory T cells,are generated under steady-state *** accumulate during aging in both humans and mice.2 By comparing the TCR repertoire of young and old mice,an early study identified age-dependent clonal expansion and age-related changes in CD8^(+) but not CD4^(+) T cells.3 Interestingly,more than 50%of CD62L^(hi)CD44^(hi) central memory T cells in the peripheral blood of aged naive mice have been suggested to represent virtual memory T cells based on their lower expression levels of CD49d.4 Infection studies in mice employing Listeria monocytogenes showed that both virtual memory T cells and conventional antigen-specific memory T cells were able to provide protection.5 However,in contrast to virtual memory T cells,conventional memory T cells produced fivefold higher levels of IFN-γupon short-term in vitro TCR stimulation.

关键词： lymph retention exposure

＂Fluidic Diode＂ for Passive Unidirectional Liquid Transport Bioinspired by the Spermathecae of Fleas

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Journal of Bionic Engineering 2018年第1期15卷 42-56页

作者： Gerda Buchberger Alexander Kogler Agnes Weth Richard Baumgartner Philipp Comanns siegfried Bauer Werner Baumgartner Institute of Biomedical Mechatronics Johannes Kepler University Linz Altenberger Str. 69 A-4040 Linz Austria institute of Experimental Physics Department of Soft Matter Physics Johannes Kepler University Linz Altenberger Str. 69 A-4040 Linz Austria Institute of Biology II RWTH Aachen University Worringerweg 3 D-52074 Aachen Germany

We present a device for passive unidirectional liquid transport. The capillary channels used are bioinspired by the shape of the spermathecae （receptaculum seminis） of rabbit fleas （Spilopsyllus cuniculi） and rat fleas （Xenopsytla cheopis）. The spermatheca is an organ of female fleas that stores sperm until suitable conditions to lay eggs are found. We translated and multiplied the natural form and function of a spermatheca to create a continuous capillary system from which we designed our microfluidic device based directly on the model from nature. Applying the Young-Laplace equation, we derived a theoretical description of local liquid transport, which enables model-guided design. We arranged the bioinspired capillaries in parallel and engraved them in poly（methyl methacrylate）（PMMA） plates by CO2 laser ablation. The fabricated structures transport soapy water passively （i.e., without external energy input） in the forward direction at velocities of about 1 mm＇s i while halting the liquid fronts completely in the backward direction. The bio- inspired capillary channels are capable of unidirectional liquid transport against gravity. Distance and velocity measurements prove the feasibility of the concept. Unidirectional passive liquid transport might be advantageous in technical surfaces for liquid man- agement, for instance, in biomedical microfluidics, lab-on-chip, lubrication, electronics cooling and in micro-analysis devices.

关键词： liquid diode wetting passive unidirectional liquid transport capillary bioinspired

EVA NEXUS-Phaco performance study

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International Journal of Ophthalmology(English edition) 2024年第8期17卷 1447-1452页

作者： Lukas Feldhaus Andreas Ohlmann Stefan Kassumeh siegfried Priglinger Wolfgang Mayer Department of Ophthalmology University HospitalLudwig-Maximilians-University MunichMunich 80336Germany

AIM:To investigate a novel phacoemulsification system“EVA NEXUS”(D.O.R.C.,Dutch Opthalmic Research Center)in comparison to the existing system“EVA”in clinical *** to compare both phacoemulsification systems in terms of efficiency,safety and postoperative inflammatory ***:In this study standardized cataract surgery was performed on both eyes of the study participant,using the“EVA system”(control group,n=20)on one eye and the“EVA NEXUS system”(intervention group,n=20)on the other *** patients with cataract LOCS Grading 1-3 and no accompanying eye diseases were included in this study.A total of 20 patients were included in this study,with each treatment arm including 20 *** surgery a 0.1 mL aqueous humor sample was collected 1min after phacoemulsification to measure the total prostaglanin E2 concentrations using an enzyme-linked immunosorbent *** endothelial cell count,visual and refractive outcomes,and anterior chamber flare were evaluated preoperatively,and 1d,1wk,and 3mo ***:There were no statistically significant differences between both groups regarding intraoperative safety parameters including effective phacoemulsification time(P=0.904),balanced saline solution flow(P=0.701)and total surgery time(P=0.565).Postoperative prostaglandin E2 levels,anterior chamber flare as well as endothelial cell loss tended to be lower in the NEXUS-Group,however not being statistically significant(P=0.718;0.164;0.486).Both systems provided similar clinical outcomes,regarding best corrected visual acuity and refractive parameters,showing no statistically significant differences between both ***:Both systems show a high level of safety and efficency with similar results in terms of safety parameters including postoperative inflammatory activity and endothelial cell loss as well as visual and refractive *** statistically not significant,the EVA NEXUS system tends to cause less postoperative inflammatio

关键词： cataract surgery phacoemulsification fluidics instrument

新型大环磺酰胺肽模拟物的设计及其关键前体的合成

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高等学校化学学报 2001年第12期22卷 2045-2047页

作者：赵宝祥 siegfried Blechert 山东大学化学与化工学院济南250100 德国柏林工业大学有机化学研究所柏林10623

A route of synthesis of a novel macrocyclic sulfonamide peptidomimetics \%via\% ring closing metathesis(RCM) has been designed. Allyl glutaric anhydride has been synthesized from commercially available diethyl allylmanolate and \%tert\% butyl acrylate by the Michael reaction and hydrolysis followed by decarboxylation and dehydration. Then, allyl hydrogen 2\|allylglutarate, a precursor for RCM, has been prepared. The synthesis of N \|allyl\|2\|ethoxycarbonyl\|2\|aminoethylsulfonyl amide, another precursor, has been accomplished from cystine.

关键词：磺酰胺肽模拟物 Michael加成 2-烯丙基戊二酸酐 2-烯丙基戊二酸单烯丙基酯烯交换闭环反应

Having a Partner and Having Children:Comparisons of Adults with Congenital Heart Disease and the General Population:A 15-Year Case-Control Study

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Congenital Heart Disease 2023年第3期18卷 337-348页

作者： siegfried Geyer Claudia Dellas Thomas Paul Matthias Müller Kambiz Norozi Medical Sociology Unit Hannover Medical SchoolHannover30625Germany Department of Pediatric Cardiology Intensive Care Medicine and NeonatologyUniversity Medical Center GoettingenGoettingenGermany Department of Pediatrics Western UniversityLondonOntarioCanada Department of Pediatric Cardiology and Intensive Care Medicine Hannover Medical SchoolHannoverGermany

Objectives:To examine whether patients with congenital heart disease(CHD)are less likely to have a partner or children than individuals from the general ***:Longitudinal study with two assessments of the same patients(n=244)from a hospital population and controls(n=238)from the German Socio-Economic Panel(GSOEP)using parental education,patients age,and sex as matching *** first patient study was conducted between 5/2003 and 6/2004,the second one between 5/2017 and 4/*** were drawn from GSOEP-surveys 2004 and ***-severity was classified according to type of surgery:curative,reparative,or *** single was used as outcome measure,for offspring the outcome was having children or ***:Among women with CHD the rate of those living single was higher than among controls with the differences depending on disease complexity(curative:OR=5.5;reparative:OR=1.9;palliative:OR=2.7).No statistically significant differences between patients and controls emerged in the male study *** respect to children a marked difference emerged between women with CHD and *** patients the odds of having children were lower than among controls(curative:OR=0.3;reparative:OR=0.3;palliative:OR=0.2).The rate of patients with children with CHD(women:5.6%;men:4.9%)was higher than expected(1%)if compared with the general ***:Using partnership and children as outcome criteria,patients with CHD are disadvantaged if compared to subjects from the general *** female patients the social consequences of the disease turned out as more pervasive than in women.

关键词： Congenital heart disease children partnership panel study case-control study

Ecstasy-induced optic disc swelling and consequent visual loss

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International Journal of Ophthalmology(English edition) 2020年第3期13卷 520-522页

作者： Michaela Ramsauer Stephan Thurau siegfried Priglinger Efstathios Vounotrypidis Department of Ophthalmology Ludwig-Maximilians-UniversityMunich 80336Germany

Dear Editor,We present the first reported case of unilateral optic disc swelling with subsequent persistent loss of vision triggered by ecstasy consumption in the case of a young *** is one of the most commonly consumed recreational drugs among young *** main constituent and active substance is 3,4-methylenedioxymethamphetamine(MDMA).

关键词： Ecstasy optic disc swelling visual loss