scholarly journals Synthesis of Triazoles by Electro-Assisted Click Reaction Using a Copper Foil Electrode

2021 ◽  
Author(s):  
Luceldi Carre-Rangel ◽  
Karla Espinoza ◽  
Mercedes Oropeza-Guzmán ◽  
Ignacio Rivero
Keyword(s):  
Copper Foil ◽  
Click Reaction ◽  
Reference Electrode ◽  
Process Efficiency ◽  
Water Medium ◽  
Click Reactions ◽  
Onset Potential ◽  
Wide Range ◽  
Biological Environment

This paper presents an innovative pathway for the synthesis of triazoles using the well-known “click chemistry” assisted by the electrochemical oxidation of metallic Cu0. The click reaction is used to couple a wide range of biological interest compounds. In this case, faster and less polluting methods for a biological environment was achived by in situ Cu0 electrooxidation, providing the suitable quantity of catalyst required by click reaction. The electrochemical cell was composed of a copper foil as the working electrode, a platinum wire serving as a counter electrode, and an Ag/AgCl wire as the reference electrode. Linear anodic sweep voltammetry in a tert-butanol-water medium (1:1), an electrolyte of tetrabutylammonium tetrafluoroborate (TBATFB), showed the onset potential of Cu0 electrooxidation. Using the same electrode configuration three different triazoles were prepared under constant electrode potential, in a short time (60 min), and splendid yields (78-90%). These results indicate that the in situ CuI formation occurs on the surface of the copper foil. A pulse potential program has also been implemented in which a yield of 92% was achieved, reducing electrode passivation and consequently increasing the process efficiency. The electroassisted click reactions are highly efficient to produce triazoles by an innovative electrochemical reaction. The products were characterized by infrared (IR), nuclear magnetic resonance (1H and 13C NMR), and mass spectrometry (MS).

scholarly journals Enhanced Antibacterial Activity of Poly (dimethylsiloxane) Membranes by Incorporating SiO2 Microspheres Generated Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 705 ◽  
Author(s):  
Qihui Shen ◽  
Yixuan Shan ◽  
Yang Lü ◽  
Peng Xue ◽  
Yan Liu ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Resistance ◽  
Click Reaction ◽  
Low Cost ◽  
Thiol Group ◽  
Water Contact ◽  
Stabilizing Agents ◽  
Wide Range ◽  
Sio2 Microspheres

The nonspecific adsorption of proteins and bacteria on the surface of polydimethylsiloxane (PDMS) had been a serious concern in a wide range of applications, such as medical devices. In order to improve the anti-adhesive and antibacterial capability, bare silver nanoparticles (AgNPs, ~15 nm) were generated in-situ on their surface without extra reducing and stabilizing agents. The main reason for this was that the SiO2 microspheres that are covalent bonded to the bulked PDMS could not only generate AgNPs spontaneously but also insure that no AgNPs were released to the environment. Meanwhile, the thiol-group-functionalized SiO2 microspheres self-assembled on the surface of PDMS by thiol-vinyl click reaction without any impact on their biomedical applications. After the modification of SiO2 microspheres with AgNPs, the surface of PDMS showed a smaller water contact angle than before, and the adhesion and growth of E. coli and Bacillus subtilis were effectively inhibited. When the monolayer of SiO2 microspheres with AgNPs was assembled completely on the surface of PDMS, they present improved bacterial resistance performance (living bacteria, 0%). This approach offers an antibacterial and anti-adhesive surface bearing small and well-defined quantities of in-situ generated AgNPs, and it is a novel, green, simple, and low-cost technique to generate AgNPs on soft biomedical substrates.

scholarly journals Facile discovery of isonitrile natural products via tetrazine based click reactions

2019 ◽  
Author(s):  
Yaobing Huang ◽  
Wenlong Cai ◽  
Antonio Del Rio Flores ◽  
Frederick Twigg ◽  
Wenjun Zhang
Keyword(s):  
Natural Products ◽  
Click Reaction ◽  
In Situ Reduction ◽  
Click Reactions ◽  
Microbial Cultures ◽  
First Time

A facile method for the quick discovery and quantification of isonitrile compounds from microbial cultures was established based on the isonitrile-tetrazine click reaction. A in situ reduction further enabled bioorthogonal ligation of primary and secondary isonitriles for the first time.

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

Site specific agricultural soil management with the use of new technologies

2013 ◽  
Vol 16 (1) ◽  
pp. 59-67
Keyword(s):  
New Technologies ◽  
Digital Interface ◽  
Appropriate Treatment ◽  
Wide Range ◽  
Soil Variation ◽  
Soil Information ◽  
Remote Sensing Techniques ◽  
Agricultural Areas

<p>The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty of these studies is that local agronomists have immediate access to a wide range of soil information by clicking on a field parcel shown in this digital interface and, therefore, can suggest an appropriate treatment (e.g. liming, manure incorporation, desalination, application of proper type and quantity of fertilizer) depending on the field conditions and cultivated crops. A specific case study is presented in the current work with regards to the construction of the digitized Soil Map of the regional unit of Kastoria. The potential of this map can easily be realized by the fact that the mapping of the physicochemical properties of the soils in this region provided delineation zones for differential fertilization management. An experiment was also conducted using remote sensing techniques for the enhancement of the fertilization advisory software database, which is a component of the digitized map, and the optimization of nitrogen management in agricultural areas.</p>

Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik
Keyword(s):  
Asymmetric Synthesis ◽  
Chiral Auxiliary ◽  
Bioactive Molecules ◽  
One Pot ◽  
Enantiomerically Pure ◽  
Stereoselective Glycosylation ◽  
One Pot Synthesis ◽  
Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

scholarly journals A Generalization Performance Study Using Deep Learning Networks in Embedded Systems

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1031
Author(s):  
Joseba Gorospe ◽  
Rubén Mulero ◽  
Olatz Arbelaitz ◽  
Javier Muguerza ◽  
Miguel Ángel Antón
Keyword(s):  
Deep Learning ◽  
Embedded Systems ◽  
Embedded System ◽  
General Purpose ◽  
Learning Networks ◽  
Performance Study ◽  
Learning Techniques ◽  
Wide Range ◽  
Learning Architectures

Deep learning techniques are being increasingly used in the scientific community as a consequence of the high computational capacity of current systems and the increase in the amount of data available as a result of the digitalisation of society in general and the industrial world in particular. In addition, the immersion of the field of edge computing, which focuses on integrating artificial intelligence as close as possible to the client, makes it possible to implement systems that act in real time without the need to transfer all of the data to centralised servers. The combination of these two concepts can lead to systems with the capacity to make correct decisions and act based on them immediately and in situ. Despite this, the low capacity of embedded systems greatly hinders this integration, so the possibility of being able to integrate them into a wide range of micro-controllers can be a great advantage. This paper contributes with the generation of an environment based on Mbed OS and TensorFlow Lite to be embedded in any general purpose embedded system, allowing the introduction of deep learning architectures. The experiments herein prove that the proposed system is competitive if compared to other commercial systems.

scholarly journals Global soil moisture data derived through machine learning trained with in-situ measurements

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sungmin O. ◽  
Rene Orth
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Large Scale ◽  
Short Term Memory ◽  
Temporal Dynamics ◽  
Soil Moisture Data ◽  
Wide Range ◽  
Global Soil

AbstractWhile soil moisture information is essential for a wide range of hydrologic and climate applications, spatially-continuous soil moisture data is only available from satellite observations or model simulations. Here we present a global, long-term dataset of soil moisture derived through machine learning trained with in-situ measurements, SoMo.ml. We train a Long Short-Term Memory (LSTM) model to extrapolate daily soil moisture dynamics in space and in time, based on in-situ data collected from more than 1,000 stations across the globe. SoMo.ml provides multi-layer soil moisture data (0–10 cm, 10–30 cm, and 30–50 cm) at 0.25° spatial and daily temporal resolution over the period 2000–2019. The performance of the resulting dataset is evaluated through cross validation and inter-comparison with existing soil moisture datasets. SoMo.ml performs especially well in terms of temporal dynamics, making it particularly useful for applications requiring time-varying soil moisture, such as anomaly detection and memory analyses. SoMo.ml complements the existing suite of modelled and satellite-based datasets given its distinct derivation, to support large-scale hydrological, meteorological, and ecological analyses.

scholarly journals Synonymous single nucleotide polymorphism in arsenic (+3) methyltransferase of the Western mosquitofish (Gambusia affinis) and its gene expression among field populations

Ecotoxicology ◽  
2021 ◽  
Author(s):  
Daesik Park ◽  
Catherine R. Propper ◽  
Guangning Wang ◽  
Matthew C. Salanga
Keyword(s):  
Gene Expression ◽  
Sequence Variation ◽  
Allelic Variation ◽  
Arsenic Concentration ◽  
Gambusia Affinis ◽  
Contamination Level ◽  
Water Medium ◽  
Single Nucleotide ◽  
Wide Range ◽  
High Arsenic

AbstractNaturally occurring arsenic is toxic at extremely low concentrations, yet some species persist even in high arsenic environments. We wanted to test if these species show evidence of evolution associated with arsenic exposure. To do this, we compared allelic variation across 872 coding nucleotides of arsenic (+3) methyltransferase (as3mt) and whole fish as3mt gene expression from three field populations of Gambusia affinis, from water sources containing low (1.9 ppb), medium-low (3.3 ppb), and high (15.7 ppb) levels of arsenic. The high arsenic site exceeds the US EPA’s Maximum Contamination Level for drinking water. Medium-low and high populations exhibited homozygosity, and no sequence variation across all animals sampled. Eleven of 24 fish examined (45.8%) in the low arsenic population harbored synonymous single nucleotide polymorphisms (SNPs) in exons 4 and/or 10. SNP presence in the low arsenic population was not associated with differences in as3mt transcript levels compared to fish from the medium-low site, where SNPs were noted; however, as3mt expression in fish from the high arsenic concentration site was significantly lower than the other two sites. Low sequence variation in fish populations from sites with medium-low and high arsenic concentrations suggests greater selective pressure on this allele, while higher variation in the low population suggests a relaxed selection. Our results suggest gene regulation associated with arsenic detoxification may play a more crucial role in influencing responses to arsenic than polymorphic gene sequence. Understanding microevolutionary processes to various contaminants require the evaluation of multiple populations across a wide range of pollution exposures.

scholarly journals Quantification of assembly forces during creation of head-neck taper junction considering soft tissue bearing: a biomechanical study

Arthroplasty ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Toni Wendler ◽  
Torsten Prietzel ◽  
Robert Möbius ◽  
Jean-Pierre Fischer ◽  
Andreas Roth ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Work Experience ◽  
Soft Tissues ◽  
Force Sensor ◽  
Biomechanical Study ◽  
Measuring System ◽  
Wide Range ◽  
Head Neck

Abstract Background All current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in the direction of the neck axis, which is mainly influenced by the applied impulse and surrounding soft tissues. This leads to large differences in assembly forces between the surgeries. This study aimed to quantify the assembly forces of different surgeons under influence of surrounding soft tissue. Methods First, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the influence of human soft tissues. Afterwards, an in vitro model in the form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that assembly forces applied to the model corresponded to those in situ. A study involving 31 surgeons was carried out on the aforementioned in vitro model, in which the assembly forces were determined. Results A model was developed, with the influence of human soft tissues being taken into account. The assembly forces measured on the in vitro model were, on average, 2037.2 N ± 724.9 N, ranging from 822.5 N to 3835.2 N. The comparison among the surgeons showed no significant differences in sex (P = 0.09), work experience (P = 0.71) and number of THAs performed per year (P = 0.69). Conclusions All measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g., by using an appropriate surgical instrument.

Regioselective Functionalization of N-Fused Heteroaromatics via FeCl3-Catalyzed Nucleophilic Addition to Activated N-Heterocycles

Synthesis ◽  
2020 ◽  
Author(s):  
Ikyon Kim ◽  
Sung June Kim ◽  
Sunhee Lee
Keyword(s):  
Aromatic Compounds ◽  
Nucleophilic Addition ◽  
Chemical Space ◽  
Wide Range ◽  
Regioselective Functionalization

AbstractBroadening of nitrogen-fused heteroaromatic chemical space such as indolizine and pyrrolo[1,2-a]pyrazine was achieved via FeCl­3-catalyzed nucleophilic addition of these N-fused aromatic compounds to a wide range of azolinium systems generated in situ, leading to novel N-fused heteroaromatic scaffolds with dearomatized N-heterocyclic substituents regioselectively. Nucleophilic addition of indolizines and pyrrolo[1,2-a]pyrazines mainly occurred at the C1 position of the isoquinoliniums and at the C4 site of the quinoliniums.

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