Liquid Phase Hydrogenation of Benzalacet0phen0ne:Effect of Solvent,Catalyst Support,Catalytic M etal and Reaction Conditions

Innovative catalysts based on a "porous glass" support material were developed and investigated for the reduction of benzalace-tophenone. The easy preparation conditions and possibility to use different metals (e.g. Pd, Pt, Rh) for impregnation gave a broad variety of these catalysts. Hydrogenation experiments with these supported catalysts were carried out under different hydrogen pressures and temperatures. Porous glass catalysts with Pd as the active component gave chemoselective hydrogenation of benzalacetophenone, while Pt- and Rh-catalysts tended to further reduce the carbonyl group, especially at elevated hydrogen pressures and temperatures. Kinetic analysis of the reactions revealed these had zero order kinetics, which was independent of the type of porous glass support and solvent used.

Characteristics of normal human retinal pigment epithelium cells with extremes of autofluorescence or intracellular granule count

Background:Cells of the retinal pigment epithelium(RPE)accumulate different kinds of granules(lipofuscin,melanolipofuscin,melanosomes)within their cell bodies,with lipofuscin and melanolipofuscin being autofluorescent after blue light excitation.High amounts of lipofuscin granules within the RPE have been associated with the development of RPE cell death and age-related macular degeneration(AMD);however,this has not been confirmed in histology so far.Here,based on our previous dataset of RPE granule characteristics,we report the characteristics of RPE cells from human donor eyes that show either high or low numbers of intracellular granules or high or low autofluorescence(AF)intensities.Methods:RPE flatmounts of fifteen human donors were examined using high-resolution structured illumination microscopy(HR-SIM)and laser scanning microscopy(LSM).Autofluorescent granules were analyzed regarding AF phenotype and absolute number of granules.In addition,total AF intensity per cell and granule density(number of granules per cell area)were determined.For the final analysis,RPE cells with total granule number below 5th or above the 95th percentile,or a total AF intensity±1.5 standard deviations above or below the mean were included,and compared to the average RPE cell at the same location.Data are presented as mean±standard deviation.Results:Within 420 RPE cells examined,42 cells were further analyzed due to extremes regarding total granule numbers.In addition,20 RPE cells had AF 1.5 standard deviations below,28 RPE cells above the mean local AF intensity.Melanolipofuscin granules predominate in RPE cells with low granule content and low AF intensity.RPE cells with high granule content have nearly twice(1.8 times)as many granules as an average RPE cell.Conclusions:In normal eyes,outliers regarding autofluorescent granule load and AF intensity signals are rare among RPE cells,suggesting that granule deposition and subsequent AF follows intrinsic control mechanisms at a cellular level.The AF of a cell is related to the composition of intracellular granule types.Ongoing studies using AMD donor eyes will examine possible disease related changes in granule distribution and further put lipofuscin´s role in aging and AMD further into perspective.

<i>In</i>-<i>Situ</i>XAFS Characterization of PtPd Nanoparticles Synthesized by Galvanic Replacement

Platinum-palladium nanoparticles are synthesized and characterized with regard to their application in fuel cells due to their high (electro) catalytic activity. Different preparation times are applied leading to different structures, from Pd cubic to core-shell PtPd concave, and different chemical compositions. The resulting particles are studied via Transmission Electron Microscopy (TEM) and in-situ X-ray absorption fine structure (XAFS) measurements. The latter allows the investigation of the oxygen reduction reaction following the variations with varying applied potentials by analysis using the Iterative Transformation Factor Analysis (ITFA) and the creation of a two-component system that consists of metallic Pt-Pd and the related oxide. With the used model, the different concentrations of the oxide are linked to the consecutive chemical steps of the oxygen reduction reaction. Finally, the catalytic activity of the particles is determined via linear scanning voltammetry and reveals a dependence on the shape and the composition of the particles.

经皮冠状动脉介入时应用多普勒超声检测冠状动脉微栓塞

Objective: To validate an intracoronary Doppler ultrasound device for high intensity transient signals(HITS) detection and to assess the incidence of HITS during percutaneous coronary intervention(PCI). Methods and Results: In an in vitro model, particle count and number of HITS detected by an intracoronary 0.014 inch Doppler wire were closely correlated(r=0.97, p< 0.001). In the clinical study, 32 patients(mean(SD) age 61(11) years; 23 men, nine women) with coronary artery disease were treated with balloon dilatation and stent implantation for a single vessel stenosis. In these patients HITS were detected during PCI in 84%(27 of 32). Reproducibility(r=0.99, p< 0.001) and interobserver agreement(r=0.84, p< 0.001)of HITS counts were significant. The number of HITS after stent implantation was significantly higher than after balloon dilatation(11(7) v 2(4), p< 0.001). Postprocedural coronary flow velocity reserve(CFVR) was< 2.0 in 55%(16 of 29) of all patients after balloon dilatation and< 2.0 in 23%(six of 26) after stent implantation. The number of HITS after stent implantation did not differ significantly between patients with CFVR< 2.0 and patients with CFVR ≥2.0(12(8) v 10(7), not significant). Conclusions: Embolic particles can be detected as HITS by an intracoronary Doppler ultrasound device. Coronary microembolism is often observed during PCI, especially after stent implantation. However, the incidence of HITS alone does not explain a reduced CFVR after PCI.

Nanowire-supported plasmonic waveguide for remote excitation of surface-enhanced Raman scattering

Due to its amazing ability to manipulate light at the nanoscale,plasmonics has become one of the most interesting topics in the field of light–matter interaction.As a promising application of plasmonics,surface-enhanced Raman scattering(SERS)has been widely used in scientific investigations and material analysis.The large enhanced Raman signals are mainly caused by the extremely enhanced electromagnetic field that results from localized surface plasmon polaritons.Recently,a novel SERS technology called remote SERS has been reported,combining both localized surface plasmon polaritons and propagating surface plasmon polaritons(PSPPs,or called plasmonic waveguide),which may be found in prominent applications in special circumstances compared to traditional local SERS.In this article,we review the mechanism of remote SERS and its development since it was first reported in 2009.Various remote metal systems based on plasmonic waveguides,such as nanoparticle–nanowire systems,single nanowire systems,crossed nanowire systems and nanowire dimer systems,are introduced,and recent novel applications,such as sensors,plasmon-driven surface-catalyzed reactions and Raman optical activity,are also presented.Furthermore,studies of remote SERS in dielectric and organic systems based on dielectric waveguides remind us that this useful technology has additional,tremendous application prospects that have not been realized in metal systems.

Real-time molecular imaging of near-surface tissue using Raman spectroscopy

The steady progress in medical diagnosis and treatment of diseases largely hinges on the steady development and improvement of modern imaging modalities.Raman spectroscopy has attracted increasing attention for clinical applications as it is label-free,non-invasive,and delivers molecular fingerprinting information of a sample.In combination with fiber optic probes,it also allows easy access to different body parts of a patient.However,image acquisition with fiber optic probes is currently not possible.Here,we introduce a fiber optic probe-based Raman imaging system for the real-time molecular virtual reality data visualization of chemical boundaries on a computer screen and the physical world.The approach is developed around a computer vision-based positional tracking system in conjunction with photometric stereo and augmented and mixed chemical reality,enabling molecular imaging and direct visualization of molecular boundaries of three-dimensional surfaces.The proposed approach achieves a spatial resolution of 0.5 mm in the transverse plane and a topology resolution of 0.6 mm,with a spectral sampling frequency of 10 Hz,and can be used to image large tissue areas in a few minutes,making it highly suitable for clinical tissueboundary demarcation.A variety of applications on biological samples,i.e.,distribution of pharmaceutical compounds,brain-tumor phantom,and various types of sarcoma have been characterized,showing that the system enables rapid and intuitive assessment of molecular boundaries.

High REDOX RESPONSIVE TRANSCRIPTION FACTOR1 Levels Result in Accumulation of Reactive Oxygen Species in Arabidopsis thaliana Shoots and Roots

Redox Responsive Transcription Factor1 （RRTF1） in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic- and abiotic-induced redox signals. RRTF1 is highly conserved in angio- sperms, but its physiological role remains elusive. Here we show that inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species （ROS） accumulation in response to stress. Transgenic lines overexpressing RRTF1 are impaired in root and shoot development, light sensitive, and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica, which reduces ROS accumulation locally in roots and systemi- cally in shoots, and by antioxidants and ROS inhibitors that scavenge ROS. More than 800 genes were detected in mature leaves and seedlings of transgenic lines overexpressing RRTF1; ∽40% of them have stress-, redox-, ROS-regulated-, ROS-scavenging-, defense-, cell death- and related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box-like sequences in the promoter of RRTFl-responsive genes. Upregulation of RRTF1 by stress stimuli and H202 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenet- ically related RAP2.6, which contains a GCC-box-like sequence in its promoter, but transgenic lines overexpressing RAP2.6 do not accumulate higher ROS levels. RRTF1 also stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the elevated levels of the highly conserved RRTF1 induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals.

DNA Damage Response in Hematopoietic Stem Cell Ageing

Maintenance of tissue-specific stem cells is vital for organ homeostasis and organismal longevity.Hematopoietic stem cells（HSCs） are the most primitive cell type in the hematopoietic system.They divide asymmetrically and give rise to daughter cells with HSC identity（selfrenewal） and progenitor progenies（differentiation）,which further proliferate and differentiate into full hematopoietic lineages.Mammalian ageing process is accompanied with abnormalities in the HSC self-renewal and differentiation.Transcriptional changes and epigenetic modulations have been implicated as the key regulators in HSC ageing process.The DNA damage response（DDR）in the cells involves an orchestrated signaling pathway,consisting of cell cycle regulation,cell death and senescence,transcriptional regulation,as well as chromatin remodeling.Recent studies employing DNA repair-deficient mouse models indicate that DDR could intrinsically and extrinsically regulate HSC maintenance and play important roles in tissue homeostasis of the hematopoietic system.In this review,we summarize the current understanding of how the DDR determines the HSC fates and finally contributes to organismal ageing.

第三代羟乙基淀粉（HES130／0．4）在复苏中应用的系统性综述：安全性尚未得到充分肯定

背景羟乙基淀粉（hydroxyethyl starches，HES）已广泛应用于外科、急诊科、重症监护患者的血管内容量治疗，但可能会影响凝血功能、肾功能，造成瘙痒、组织潴留和一定的死亡率。一般认为第三代羟乙基淀粉（HES130／0．4）能减少这些并发症。在达到相似的血流动力学终点时所需晶体与胶体量之比为（3—4）：1。我们的研究目的在于评定以往发表的有关HES130／0．4进行复苏的试验是否设计足够科学，从而得出HES130／0．4是否安全的结论。此外，我们还将评价目标导向液体治疗中的晶体与胶体容量之比。方法系统回顾HES130／0．4用于复苏的随机对照研究。结果我们选取了56个HES130／0．4用于急性低血容量治疗的随机对照研究（randomized controlledtrials，RCTs），主要是择期外科手术（45例）。外科手术研究大多样本量小（HES组病例数中位数为25，全距为10。90）、观察时间短（中位数为12小时，全距为0．5—144小时），HES累积量的中位数为2465mi（全距为328—6229m1），相当于70kg的患者使用量为35ml／kg，一天的最大用量为50ml／kg。临床监测指标各异。60％的对照组使用的液体为其他的羟乙基淀粉、明胶或右旋糖酐，这些液体与羟乙基淀粉不良反应相似。由于这些研究样本量太小，对照组液体选择不合适，观察时间太短，因此并没有针对临床重要的安全性结局进行设计。而且由于患者选择组不一样，以及评价结果的定义不一样，因此这些研究的结果很难结合在一起。这些研究没有做出任何有关HES130／0．4安全性的结论。一般均认为需要3—4倍胶体量的晶体才能达到与胶体相似的血流动力学指标，我们发现在一些外科研究中这一比例可能更低（平均数为1．8，标准差为0．1）。结论总之，HES130／0．4治疗时所需液体量的降低在某种程度上被高估了。老的羟乙基淀粉可能会引起一些严重的副作用，临床医生应知道，尽管有关的研究报道很多，但目前仍没有明确的证据表明HES130／0．4能安全应用于外科、急诊和重症监护患者。

Achromatic optical retardation from perovskites

Nature Photonics 15,813-816(2021)https://doi.org/10.1038/s41566-021-00865-0 Control of light polarization over a wide range of optical wavelengths is highly desirable within a variety of applications.Fabrication of waveplates,allowing for achromatic retardation usually requires a sophisticated combination of multiple layers of birefringent materials.