scholarly journals Wide Range Responsivity Photodetector of Zr-Au-Ag Oxide NPs Prepared By Pulsed Laser Ablation

2021 ◽  
Vol 2114 (1) ◽  
pp. 012073
Author(s):  
Haider J. Hassan ◽  
Ahmed k. Abbas ◽  
Isam M. Ibrahim
Keyword(s):  
Laser Ablation ◽  
Imaging Techniques ◽  
Real Space ◽  
Composite Particles ◽  
Synthetic Approach ◽  
Preparation Methods ◽  
Promising Tool ◽  
Gold Silver ◽  
Wide Range ◽  
Controlled Deposition

Abstract Metal-ceramic composite particles are of increasing interest due to their potential applications in photodetectors as well as next-generation catalysts. The zirconium-gold system has received little attention due to the lack of controllable preparation methods. Well-known methods for the deposition of gold Nano shells on zirconium spheres, however, should be adaptable for similar zirconium-based materials. Here, we present a method to synthetic approach to the well-controlled deposition of gold on the surface by laser ablation. The results shed light on the parameters governing the preparation of zirconium _ gold composite particles and our synthetic approach provides a promising tool for future developments in complex nanomaterials design. As well as studying the structural and optical properties of gold, silver and zirconium nanoparticles by preparing those particles in the above method and studying the properties of the resulting materials as a photodetector. The surface morphology, structure, and composition of the layer were studied using a variety of spectroscopic diffraction and real-space imaging techniques, including SEM, EDX and AFM.

scholarly journals Seeded Growth Synthesis of Zirconia@Gold Particles in Aqueous Solution

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1197 ◽  
Author(s):  
Gregor Thomas Dahl ◽  
Jan-Dominik Krueger ◽  
Sebastian Döring ◽  
Horst Weller ◽  
Tobias Vossmeyer
Keyword(s):  
Sol Gel ◽  
Composite Particles ◽  
Synthetic Approach ◽  
Seeded Growth ◽  
Preparation Methods ◽  
Promising Tool ◽  
Aminomethylphosphonic Acid ◽  
Potential Applications ◽  
Incremental Growth ◽  
Controlled Deposition

Metal-ceramic composite particles are of increasing interest due to their potential applications in photonic metamaterials as well as next-generation catalysts. The zirconia-gold system has received little attention due to the lack of controllable preparation methods. Well-known methods for the deposition of gold nanoshells on silica spheres, however, should be adaptable for similar zirconia-based materials. Here, we present a novel synthetic approach to the well-controlled deposition of gold on the surface of sol-gel derived zirconia mesoparticles by a stepwise method involving the immobilization of gold nanoparticles and repeated seeded-growth steps. We show that the immobilization efficiency is strongly enhanced by acidification with hydrochloric acid and additional employment of aminomethylphosphonic acid as coupling agent. The optimum conditions are identified and the subsequent incremental growth by seeded reduction of gold is demonstrated. The results shed light on the parameters governing the preparation of zirconia@gold composite particles and our synthetic approach provides a promising tool for future developments in complex nanomaterials design.

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

scholarly journals Optical Imaging of Beta-Amyloid Plaques in Alzheimer’s Disease

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 255
Author(s):  
Ziyi Luo ◽  
Hao Xu ◽  
Liwei Liu ◽  
Tymish Y. Ohulchanskyy ◽  
Junle Qu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Imaging ◽  
Imaging Techniques ◽  
High Sensitivity ◽  
Pathological Feature ◽  
Promising Tool ◽  
Abnormal Accumulation ◽  
Accumulation Mechanism ◽  
The Brain

Alzheimer’s disease (AD) is a multifactorial, irreversible, and incurable neurodegenerative disease. The main pathological feature of AD is the deposition of misfolded β-amyloid protein (Aβ) plaques in the brain. The abnormal accumulation of Aβ plaques leads to the loss of some neuron functions, further causing the neuron entanglement and the corresponding functional damage, which has a great impact on memory and cognitive functions. Hence, studying the accumulation mechanism of Aβ in the brain and its effect on other tissues is of great significance for the early diagnosis of AD. The current clinical studies of Aβ accumulation mainly rely on medical imaging techniques, which have some deficiencies in sensitivity and specificity. Optical imaging has recently become a research hotspot in the medical field and clinical applications, manifesting noninvasiveness, high sensitivity, absence of ionizing radiation, high contrast, and spatial resolution. Moreover, it is now emerging as a promising tool for the diagnosis and study of Aβ buildup. This review focuses on the application of the optical imaging technique for the determination of Aβ plaques in AD research. In addition, recent advances and key operational applications are discussed.

scholarly journals Potential predictors of severe cardiovascular involvement in Marfan syndrome: the emphasized role of genotype–phenotype correlations in improving risk stratification—a literature review

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Roland Stengl ◽  
Bence Ágg ◽  
Miklós Pólos ◽  
Gábor Mátyás ◽  
Gábor Szabó ◽  
...  
Keyword(s):  
Risk Stratification ◽  
Marfan Syndrome ◽  
Current Knowledge ◽  
Imaging Techniques ◽  
Connective Tissue Disorder ◽  
Main Body ◽  
Wide Range ◽  
Stratification System ◽  
Genetically Determined ◽  
Aortic Dissections

Abstract Background Marfan syndrome (MFS) is a genetically determined systemic connective tissue disorder, caused by a mutation in the FBN1 gene. In MFS mainly the cardiovascular, musculoskeletal and ocular systems are affected. The most dangerous manifestation of MFS is aortic dissection, which needs to be prevented by a prophylactic aortic root replacement. Main body The indication criteria for the prophylactic procedure is currently based on aortic diameter, however aortic dissections below the threshold defined in the guidelines have been reported, highlighting the need for a more accurate risk stratification system to predict the occurrence of aortic complications. The aim of this review is to present the current knowledge on the possible predictors of severe cardiovascular manifestations in MFS patients, demonstrating the wide range of molecular and radiological differences between people with MFS and healthy individuals, and more importantly between MFS patients with and without advanced aortic manifestations. These differences originating from the underlying common molecular pathological processes can be assessed by laboratory (e.g. genetic testing) and imaging techniques to serve as biomarkers of severe aortic involvement. In this review we paid special attention to the rapidly expanding field of genotype–phenotype correlations for aortic features as by collecting and presenting the ever growing number of correlations, future perspectives for risk stratification can be outlined. Conclusions Data on promising biomarkers of severe aortic complications of MFS have been accumulating steadily. However, more unifying studies are required to further evaluate the applicability of the discussed predictors with the aim of improving the risk stratification and therefore the life expectancy and quality of life of MFS patients.

scholarly journals A Structurally Variable Hinged Tetrahedron Framework from DNA Origami

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
David M. Smith ◽  
Verena Schüller ◽  
Carsten Forthmann ◽  
Robert Schreiber ◽  
Philip Tinnefeld ◽  
...  
Keyword(s):  
Self Assembly ◽  
Gel Electrophoresis ◽  
Imaging Techniques ◽  
Building Blocks ◽  
Dna Origami ◽  
Microscopy Technique ◽  
Wire Frame ◽  
Wide Range ◽  
Potential Applications ◽  
Linker Molecules

Nanometer-sized polyhedral wire-frame objects hold a wide range of potential applications both as structural scaffolds as well as a basis for synthetic nanocontainers. The utilization of DNA as basic building blocks for such structures allows the exploitation of bottom-up self-assembly in order to achieve molecular programmability through the pairing of complementary bases. In this work, we report on a hollow but rigid tetrahedron framework of 75 nm strut length constructed with the DNA origami method. Flexible hinges at each of their four joints provide a means for structural variability of the object. Through the opening of gaps along the struts, four variants can be created as confirmed by both gel electrophoresis and direct imaging techniques. The intrinsic site addressability provided by this technique allows the unique targeted attachment of dye and/or linker molecules at any point on the structure's surface, which we prove through the superresolution fluorescence microscopy technique DNA PAINT.

Historical Dynamics

2018 ◽  
Author(s):  
Peter Turchin
Keyword(s):  
Religious Conversion ◽  
Synthetic Approach ◽  
Dynamical Processes ◽  
Factors Affecting ◽  
Historical Processes ◽  
Wide Range ◽  
Historical Dynamics ◽  
State Breakdown ◽  
Political Economic ◽  
High Degree

Many historical processes are dynamic. Populations grow and decline. Empires expand and collapse. Religions spread and wither. Natural scientists have made great strides in understanding dynamical processes in the physical and biological worlds using a synthetic approach that combines mathematical modeling with statistical analyses. Taking up the problem of territorial dynamics—why some polities at certain times expand and at other times contract—this book shows that a similar research program can advance our understanding of dynamical processes in history. The book develops hypotheses from a wide range of social, political, economic, and demographic factors: geopolitics, factors affecting collective solidarity, dynamics of ethnic assimilation/religious conversion, and the interaction between population dynamics and sociopolitical stability. It then translates these into a spectrum of mathematical models, investigates the dynamics predicted by the models, and contrasts model predictions with empirical patterns. The book's highly instructive empirical tests demonstrate that certain models predict empirical patterns with a very high degree of accuracy. For instance, one model accounts for the recurrent waves of state breakdown in medieval and early modern Europe. And historical data confirm that ethno-nationalist solidarity produces an aggressively expansive state under certain conditions (such as in locations where imperial frontiers coincide with religious divides). The strength of the book's results suggests that the synthetic approach advocated can significantly improve our understanding of historical dynamics.

Updates and Advances: Pediatric Musculoskeletal Infection Imaging Made Easier for Radiologists and Clinicians

2021 ◽  
Vol 25 (01) ◽  
pp. 167-175
Author(s):  
Michael S. Furman ◽  
Ricardo Restrepo ◽  
Supika Kritsaneepaiboon ◽  
Bernard F. Laya ◽  
Domen Plut ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Imaging Techniques ◽  
Daily Clinical Practice ◽  
Infants And Children ◽  
Imaging Evaluation ◽  
Musculoskeletal Infection ◽  
Wide Range ◽  
Life Threatening ◽  
Optimal Patient Management

AbstractInfants and children often present with a wide range of musculoskeletal (MSK) infections in daily clinical practice. This can vary from relatively benign superficial infections such as cellulitis to destructive osseous and articular infections and life-threatening deep soft tissue processes such as necrotizing fasciitis. Imaging evaluation plays an essential role for initial detection and follow-up evaluation of pediatric MSK infections. Therefore, a clear and up-to-date knowledge of imaging manifestations in MSK infections in infants and children is imperative for timely and accurate diagnosis that, in turn, can result in optimal patient management. This article reviews an up-to-date practical imaging techniques, the differences between pediatric and adult MSK infections, the spectrum of pediatric MSK infections, and mimics of pediatric MSK infections encountered in daily clinical practice by radiologists and clinicians.

Characterization of luminous beams from laser ablation by imaging techniques

1995 ◽  
Vol 232 (5-6) ◽  
pp. 576-580 ◽  
Author(s):  
Kuo-mei Chen ◽  
Ming-huei Tzeng ◽  
Chen-nan Kuo ◽  
Cheng-chih Pei
Keyword(s):  
Laser Ablation ◽  
Imaging Techniques

Influence of Laser Irradiation and Ambient Gas in Preparation of PZT Films by Laser Ablation

1990 ◽  
Vol 191 ◽  
Author(s):  
Akiharu Morimoto ◽  
Shigeru Otsubo ◽  
Tatsuo Shimizu ◽  
Toshiharu Minamikawa ◽  
Yasuto Yonezawa ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Laser Irradiation ◽  
Perovskite Structure ◽  
Film Surface ◽  
Target Material ◽  
Laser Ablation Method ◽  
Wide Range ◽  
Pzt Films ◽  
Ambient Gas ◽  
Substrate Temperatures

ABSTRACTPb(Zr0.52Ti0. 48)O3 (PZT) films were prepared on r-plane sapphire substrates by the laser ablation method utilizing ArF excimer laser in O2 or N2O environment. The composition of the films deposited in O2 environment was found to be fairly close to the composition of the target material for a wide range of substrate temperatures, 400 – 750 °c. Increasing the laser fluence (the laser power density) for the ablation enhances the formation of the perovskite structure rather than the pyrochlore one. Use of N2O ambient gas instead of O2 gas enhances the formation of the perovskite structure of PZT films. Furthermore, it was found that a laser irradiation on the growing film surface during deposition enhances the formation of the perovskite structure.

scholarly journals The 3-O-sulfation of heparan sulfate modulates protein binding and lyase degradation

2021 ◽  
Vol 118 (3) ◽  
pp. e2012935118
Author(s):  
Pradeep Chopra ◽  
Apoorva Joshi ◽  
Jiandong Wu ◽  
Weigang Lu ◽  
Tejabhiram Yadavalli ◽  
...  
Keyword(s):  
Heparan Sulfate ◽  
Binding Proteins ◽  
Factor Xa ◽  
Tissue Expression ◽  
Cell Entry ◽  
Synthetic Approach ◽  
Array Technology ◽  
Wide Range ◽  
Simplex Virus

Humans express seven heparan sulfate (HS) 3-O-sulfotransferases that differ in substrate specificity and tissue expression. Although genetic studies have indicated that 3-O-sulfated HS modulates many biological processes, ligand requirements for proteins engaging with HS modified by 3-O-sulfate (3-OS) have been difficult to determine. In particular, the context in which the 3-OS group needs to be presented for binding is largely unknown. We describe herein a modular synthetic approach that can provide structurally diverse HS oligosaccharides with and without 3-OS. The methodology was employed to prepare 27 hexasaccharides that were printed as a glycan microarray to examine ligand requirements of a wide range of HS-binding proteins. The binding selectivity of antithrombin-III (AT-III) compared well with anti-Factor Xa activity supporting robustness of the array technology. Many of the other examined HS-binding proteins required an IdoA2S-GlcNS3S6S sequon for binding but exhibited variable dependence for the 2-OS and 6-OS moieties, and a GlcA or IdoA2S residue neighboring the central GlcNS3S. The HS oligosaccharides were also examined as inhibitors of cell entry by herpes simplex virus type 1, which, surprisingly, showed a lack of dependence of 3-OS, indicating that, instead of glycoprotein D (gD), they competitively bind to gB and gC. The compounds were also used to examine substrate specificities of heparin lyases, which are enzymes used for depolymerization of HS/heparin for sequence determination and production of therapeutic heparins. It was found that cleavage by lyase II is influenced by 3-OS, while digestion by lyase I is only affected by 2-OS. Lyase III exhibited sensitivity to both 3-OS and 2-OS.

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