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Molecularly Imprinted Polymer Based Electrochemical Sensor for the Detection of Azoxystrobin in Aqueous Media
Get PDFThis work presents an electrochemical sensor detecting a fungicide azoxystrobin AZO in aqueous environments. This AZO sensor utilises a thin film metal electrode TFME combined with the AZO selective molecularly imprinted polymer AZO MIP . The AZO MIP was directly generated on TFME through electrochemical polymerization from the solution containing two functional monomers aniline Ani and m phenylenediamine mPD , and the template AZO, which was afterwards removed to form AZO selective cavities in the polymer matrix. The AZO MIP preparation was characterised by electrochemical and ellipsometry measurements. Optimization of the synthesis parameters, including the charge density applied during electro deposition, the monomer to template ratio, solution pH, and incubation time, was performed to enhance the sensor s performance. The results demonstrated that AZO sensor achieved a low limit of detection LOD of 3.6 nM and a limit of quantification LOQ of 11.8 nM in tap water, indicating their sensitivity in a complex aqueous environment. The sensor also exhibited satis factory selectivity for AZO in both ultrapure and tap water samples, and achieved a good recovery 94 119 for the target analyte. This study highlights the potential of MIP based electrochemical sensors for rapid and accurate detection of fungicide contaminants in water, contributing to the advancement of analytical tools for water quality monitoring and risk assessmen
Improving the Accessibility and Efficiency of Proton Irradiations for 4He 3He Thermochronology
Get PDFSynthesizing uniform and high concentrations of 3He within minerals via high energy proton irradiation is paramount for 4He 3He thermochronology and helium diffusion kinetic studies. Proton irradiations of geological material have hitherto exclusively been routinely conducted at the Francis H. Burr Proton Therapy Center FHB ; we thus explored alternative irradiation protocols at two European based facilities with the intention to improve the accessibility and efficiency in obtaining 4He 3He data. We conducted a single irradiation at the Paul Scherrer Institute PSI using an approach most similar to that used at FHB wide, high energy beam , and four irradiations at the Helmholtz Zentrum Berlin HZB using a newly developed in vacuum irradiation protocol in a narrow, lower energy but high intensity beam. Internal shards of Durango apatite were irradiated in all experiments; 4He 3He release spectra and bulk 3He concentrations of PSI and HZB irradiated Durango shards were compared to those from FHB to assess the quality of each experiment in terms of the quantity and uniformity of synthesized 3He. While 3He was uniformly synthesized in PSI irradiated Durango shards, the bulk 3He concentration was below the required threshold due to limitations on the maximum allotted proton flux. Over the course of four irradiation experiments at HZB, the protocol evolved to ensure that uniform and high concentrations of 3He can be consistently induced. Furthermore, we demonstrate how HZB irradiations can be replicated using computer simulations, permitting the use of simulations to inform future modifications of the irradiation protocol in order to optimize the uniformity of the 3He distribution across all irradiated sample
Proton Beam Based Production of Positron Emitters by Exploiting the 27Al p,x 22Na Reaction
Get PDFPositron annihilation experiments on an laboratory scale depend on the supply and the availability of beta emitters. Here we present the production of positron sources based on the Al 27 p,x Na 22 reaction by irradiation of Al with a 68 MeV proton beam. We simulated the energy loss, range and radial scattering of the protons in Al in order to design a simple target consisting of a stack of Al discs. Our approach allows i the direct use of the Al discs as positron emitters that inherently avoids wet chemical processes as usually applied in commercial production of carrier free Na 22, ii the production of multiple positron sources at once, and iii the simple measurement of the depth and lateral distribution of Na 22. We precisely determined the cross section of the Al 27 p,x Na 22 reaction which was found to differ from literature values particularly for proton energies between 27 and 40 MeV. The activity of all nuclides produced apart from Na 22 was shown to be negligible 15 days after irradiation. The production of radionuclides such as Sc 48, Mn 54 and Co 56 can be prevented by using Al of a higher purity. The concept presented here can easily be adapted for the production of stronger Na 22 sources by increasing the proton current or and the irradiation tim
Exploring the electrochemical and physical stability of lithium ion cells exposed to liquid nitrogen
No full textAssessment of imaging performance for metal alloys of the first Italian neutron imaging beamline NICHE Pavia, Italy
Get PDFIn this paper, the imaging capabilities and performance of the new neutron imaging beamline developed at the LENA facility of Pavia Italy in the framework of the NICHE project Neutron Imaging in Cultural HEritage are presented. For this purpose, the estimation of bronze and brass alloys attenuation coefficient has been obtained through imaging analysis of a set of Cu based alloy reference samples produced ad hoc with chemical composition similar to ancient artefacts. In addition, some samples were realised using a different cooling ramp in order to test the influence of the alloy production procedures in neutron attenuation. Moreover, the tomographic capabilities of the beamline were tested for different metallic and plastic material
Dynamic in situ reconstruction of NiSe2 promoted by interfacial Ce2 CO3 2O for enhanced water oxidation
Get PDFUnderstanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity. Herein, we present a synthesis of NiSe2 Ce2 CO3 2O heterostructure and demonstrate the efficacy of interfacial Ce2 CO3 2O in promoting the formation of catalytically active centers to improve oxygen evolution activity. In situ Raman spectroscopy shows that incorporation of Ce2 CO3 2O into NiSe2 causes a cathodic shift of the Ni2 amp; 8594;Ni3 transition potential. Operando electrochemical impedance spectroscopy reveals that strong electronic coupling at heterogeneous interface accelerates charge transfer process. Furthermore, density functional theory calculations suggest that actual catalytic active species of NiOOH transformed from NiSe2, which is coupled with Ce2 CO3 2O, can optimize electronic structure and decrease the free energy barriers toward fast oxygen evolution reaction OER kinetics. Consequently, the resultant NiSe2 Ce2 CO3 2O electrode exhibits remarkable electrocatalytic performance with low overpotentials 268 304 mV 50 100 mA cm amp; 8722;2 and excellent stability 50 mA cm amp; 8722;2 for 120 h in the alkaline electrolyte. This work emphasizes the significance of modulating the dynamic changes in developing efficient electrocatalys
Advances in Therapeutic Peptides Separation and Purification
Get PDFPeptides are gaining prominence in various fields, including the pharmaceutical industry. To meet regulatory requirements, they must achieve a certain purity threshold to ensure safe administration. Numerous purification technologies have been employed to purify peptides, aiming to reduce cost and time while being sustainable and efficient. These include chromatography, magnetic nanoparticles, isoelectric focusing, and membrane filtration. The physicochemical properties of peptides are the main driving element behind these technologies. While chromatographic separation remains the gold standard for peptide separation and purification, with various models to predict the elution behaviors of peptides, other technologies have demonstrated their capability to meet the performance of established chromatographic methodologies, with better productivity and reduced cost. This opens the door for further investigational studies to assess these outcomes and potentially introduce new techniques for peptide purification. In this review, we examine these technologies in terms of their efficiency and their ability to meet sustainability requirements, concluding with remarks and an outlook on future advancement
Structural characterization of Thogoto Virus nucleoprotein provides insights into viral RNA encapsidation and RNP assembly
No full textOrthomyxoviruses, such as influenza and thogotoviruses, are important human and animal pathogens. Their segmented viral RNA genomes are wrapped by viral nucleoproteins NPs into helical ribonucleoprotein complexes RNPs . NP structures of several influenza viruses have been reported. However, there are still contradictory models of how orthomyxovirus RNPs are assembled. Here, we characterize the crystal structure of Thogoto virus THOV NP and found striking similarities to structures of influenza viral NPs, including a two lobed domain architecture, a positively charged RNA binding cleft, and a tail loop important for trimerization and viral transcription. A low resolution cryo electron tomography reconstruction of THOV RNPs elucidates a left handed double helical assembly. By providing a model for RNP assembly of THOV, our study suggests conserved NP assembly and RNA encapsidation modes for thogoto and influenza viruse
Development of Iron Based Single Atom Materials for General and Efficient Synthesis of Amines
Get PDFEarth abundant metal based heterogeneous catalysts with highly active and at the same time stable isolated metal sites constitute a key factor for the advancement of sustainable and cost effective chemical synthesis. In particular, the development of more practical, and durable iron based materials is of central interest for organic synthesis, especially for the preparation of chemical products related to life science applications. Here, we report the preparation of Fe single atom catalysts Fe SACs entrapped in N doped mesoporous carbon support with unprecedented potential in the preparation of different kinds of amines, which represent privileged class of organic compounds and find increasing application in daily life. The optimal Fe SACs allow for the reductive amination of a broad range of aldehydes and ketones with ammonia and amines to produce diverse primary, secondary, and tertiary amines including N methylated products as well as drugs, agrochemicals, and other biomolecules amino acid esters and amides utilizing green hydroge
Acetyl CoA synthetase activity is enzymatically regulated by lysine acetylation using acetyl CoA or acetyl phosphate as donor molecule
No full textThe AMP forming acetyl CoA synthetase is regulated by lysine acetylation both in bacteria and eukaryotes. However, the underlying mechanism is poorly understood. The Bacillus subtilis acetyltransferase AcuA and the AMP forming acetyl CoA synthetase AcsA form an AcuA AcsA complex, dissociating upon lysine acetylation of AcsA by AcuA. Crystal structures of AcsA from Chloroflexota bacterium in the apo form and in complex with acetyl adenosine 5 amp; 8242; monophosphate acetyl AMP support the flexible C terminal domain adopting different conformations. AlphaFold2 predictions suggest binding of AcuA stabilizes AcsA in an undescribed conformation. We show the AcuA AcsA complex dissociates upon acetyl coenzyme A acetyl CoA dependent acetylation of AcsA by AcuA. We discover an intrinsic phosphotransacetylase activity enabling AcuA AcsA generating acetyl CoA from acetyl phosphate AcP and coenzyme A CoA used by AcuA to acetylate and inactivate AcsA. Here, we provide mechanistic insights into the regulation of AMP forming acetyl CoA synthetases by lysine acetylation and discover an intrinsic phosphotransacetylase allowing modulation of its activity based on AcP and CoA level