Fast Procedure for Aqueous Samples Investigation Using SEM and EDX for Nuclear Safeguards Purposes

Background: First developed in the 1990’s at the National Synchrotron Light Source, xray synchrotron footprinting is an ideal technique for the analysis of solution-state structure and dynamics of macromolecules. Hydroxyl radicals generated in aqueous samples by intense x-ray beams serve as fine probes of solvent accessibility, rapidly and irreversibly reacting with solvent exposed residues to provide a “snapshot” of the sample state at the time of exposure. Over the last few decades, improvements in instrumentation to expand the technology have continuously pushed the boundaries of biological systems that can be studied using the technique. Conclusion: Dedicated synchrotron beamlines provide important resources for examining fundamental biological mechanisms of folding, ligand binding, catalysis, transcription, translation, and macromolecular assembly. The legacy of synchrotron footprinting at NSLS has led to significant improvement in our understanding of many biological systems, from identifying key structural components in enzymes and transporters to in vivo studies of ribosome assembly. This work continues at the XFP (17-BM) beamline at NSLS-II and facilities at ALS, which are currently accepting proposals for use.

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An Effort to Making a Colorimitric Nano-Biosensor for Vibrio cholera Detection

Current Nanoscience ◽

10.2174/1573413716666191230154316 ◽

2020 ◽

Vol 16 (5) ◽

pp. 793-804

Author(s):

Naimeh Mahheidari ◽

Jamal Rashidiani ◽

Hamid Kooshki ◽

Khadijeh Eskandari

Keyword(s):

Gold Nanoparticles ◽

Colorimetric Assay ◽

Au Nanoparticle ◽

Bacteria Detection ◽

Great Promise ◽

Bacterial Cells ◽

Vibrio Cholera ◽

Minimum Concentration ◽

Vis Spectroscopy ◽

Fast Procedure

Background: Today, nanoparticles hold great promise in biomedical researches and applications including bacteria detection. The rapid and sensitive outcomes of bacteria detection strategies using nanoparticle conjugates become determinative, especially in bacterial outbreaks. In the current research, we focused on detecting V. cholera bacteria and its toxin using a thiocyanate/Au nanoparticle. Thiocyanate adsorbed strongly on the surface of gold nanoparticles and changed the surface by enhancing surface plasmon resonance of gold nanoparticles. Objective: This method is tried to introduce a simple and fast procedure to assay vibrio cholera. So, it is observed by the naked eyes as well. Methods: We used two antibodies (Ab) for V. cholera detection: a) a primary antibody conjugated to magnetic nanoparticles (MNPs) for trapping V. cholera bacterial cells, and b) a secondary Abconjugated thiocyanate-GNPs as a colorimetric detector. Then, an immuno-magnetic separation system connected to a colorimetric assay was designed based on the GNPs. The results were measured by ultraviolet-visible (UV-Vis) spectroscopy. Results: The results showed that gold nanoparticles are an appropriate optical assay for detecting biological samples in a minimum concentration and also it can be easily seen by the naked eyes. The linear range of this biosensor is 3.2×104 to 28×104 cells per ml. Conclusion: In this research, a colorimetric immune assay based on gold nanoparticles was designed to improve the sensitivity of V. cholera detection. Also, this method can be used for the detection of other biological agents.

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Novel palladium(II) selective membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2009555 ◽

2010 ◽

Vol 75 (5) ◽

pp. 563-575 ◽

Cited By ~ 1

Author(s):

Moslem Mohammadi ◽

Mehdi Khodadadian ◽

Mohammad K. Rofouei

Keyword(s):

Limit Of Detection ◽

Membrane Electrode ◽

Aqueous Samples ◽

Selective Determination ◽

Poly Vinyl Chloride ◽

Selective Membrane ◽

Ph Range ◽

Palladium Content ◽

Methyl Benzene

A plasticized poly(vinyl chloride) membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol (L) for highly selective determination of palladium(II) (in PdCl42– form) is developed. The electrode showed a good Nernstian response (29.6 ± 0.4 mV per decade) over a wide concentration range (3.1 × 10–7 to 1.0 × 10–2 mol l–1). The limit of detection was 1.5 × 10–7 mol l–1. The electrode has a response time of about 20 s, and it can be used for at least 2 months without observing any considerable deviation from Nernstian response. The proposed electrode could be used in the pH range of 2.5–5.5. The practical utility of the electrode has been demonstrated by its use for the estimation of palladium content in aqueous samples.

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Postprocedural Endophthalmitis or Postprocedural Intraocular Inflammation: A Diagnostic Conundrum

Case Reports in Ophthalmology ◽

10.1159/000511970 ◽

2021 ◽

pp. 418-424

Author(s):

Aisha Al Busaidi ◽

Ahmed Al-Hinai

Keyword(s):

Pars Plana Vitrectomy ◽

Povidone Iodine ◽

Complete Recovery ◽

Neovascular Glaucoma ◽

Intraocular Inflammation ◽

Aqueous Samples ◽

Patient Counseling ◽

Pars Plana ◽

Culture Negative ◽

Office Procedures

We experienced an atypical endophthalmitis occurring post consecutively performed in-office procedures; an intravitreal injection (IVI) of ranibizumab followed by an anterior chamber (AC) paracentesis performed twice in an eye with neovascular glaucoma (NVG). A 52-year-old diabetic male who was asymptomatic developed signs of endophthalmitis and decreased vision without pain in his left eye a few days post-IVI and AC paracentesis. The condition worsened after an initial vitreous tap and injection of antibiotics. Cultures of vitreous and aqueous samples were negative. Complete resolution occurred after a pars plana vitrectomy with IVI of antibiotics and steroid with removal of a dense “yellowish-brown” fibrinous plaque. The absence of pain, presence of a peculiar colored fibrin, mild-to-moderate vitritis without retinitis, negative cultures, and complete recovery despite the fulminant presentation; favor a diagnosis of inflammation over infection. We hypothesize that a micro-leak from a 26-gauge AC tap tract might have served as an entry port for 5% povidone-iodine from the ocular surface thus inciting inflammation. However, an exuberant inflammatory response that can be typically seen in NVG eyes after intraocular procedures cannot be excluded. Various causes of inflammation post-procedures, both toxic and nontoxic should be considered in atypical culture-negative fulminant endophthalmitis cases with good outcome posttreatment. Any minor ocular procedure may carry a risk of such complication. Patient counseling and care must be exercised in performing these procedures.

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Removal of pharmaceuticals from aqueous samples by adsorption using pristine polypyrrole as adsorbent: kinetic, isothermal and thermodynamic studies

International Journal of Environmental & Analytical Chemistry ◽

10.1080/03067319.2021.1938019 ◽

2021 ◽

pp. 1-18

Author(s):

Bruna Carneiro Pires ◽

Flávia Viana Avelar Dutra ◽

Tienne Aparecida Nascimento ◽

Keyller Bastos Borges

Keyword(s):

Aqueous Samples ◽

Thermodynamic Studies

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Quantitative imaging and automated fuel pin identification for passive gamma emission tomography

Scientific Reports ◽

10.1038/s41598-021-82031-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ming Fang ◽

Yoann Altmann ◽

Daniele Della Latta ◽

Massimiliano Salvatori ◽

Angela Di Fulvio

Keyword(s):

Inverse Problem ◽

Image Reconstruction ◽

Image Resolution ◽

Emission Tomography ◽

Nuclear Safeguards ◽

Activity Levels ◽

Spent Fuel ◽

Gamma Emission ◽

Cross Sectional ◽

Fuel Rods

AbstractCompliance of member States to the Treaty on the Non-Proliferation of Nuclear Weapons is monitored through nuclear safeguards. The Passive Gamma Emission Tomography (PGET) system is a novel instrument developed within the framework of the International Atomic Energy Agency (IAEA) project JNT 1510, which included the European Commission, Finland, Hungary and Sweden. The PGET is used for the verification of spent nuclear fuel stored in water pools. Advanced image reconstruction techniques are crucial for obtaining high-quality cross-sectional images of the spent-fuel bundle to allow inspectors of the IAEA to monitor nuclear material and promptly identify its diversion. In this work, we have developed a software suite to accurately reconstruct the spent-fuel cross sectional image, automatically identify present fuel rods, and estimate their activity. Unique image reconstruction challenges are posed by the measurement of spent fuel, due to its high activity and the self-attenuation. While the former is mitigated by detector physical collimation, we implemented a linear forward model to model the detector responses to the fuel rods inside the PGET, to account for the latter. The image reconstruction is performed by solving a regularized linear inverse problem using the fast-iterative shrinkage-thresholding algorithm. We have also implemented the traditional filtered back projection (FBP) method based on the inverse Radon transform for comparison and applied both methods to reconstruct images of simulated mockup fuel assemblies. Higher image resolution and fewer reconstruction artifacts were obtained with the inverse-problem approach, with the mean-square-error reduced by 50%, and the structural-similarity improved by 200%. We then used a convolutional neural network (CNN) to automatically identify the bundle type and extract the pin locations from the images; the estimated activity levels finally being compared with the ground truth. The proposed computational methods accurately estimated the activity levels of the present pins, with an associated uncertainty of approximately 5%.

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Modified Exfoliated Carbon Nanoplatelets as Sorbents for Ammonium from Natural Mineral Waters

Molecules ◽

10.3390/molecules26123541 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3541

Author(s):

Ion Ion ◽

Daniela Bogdan ◽

Monica Maria Mincu ◽

Alina Catrinel Ion

Keyword(s):

Natural Waters ◽

Mineral Waters ◽

Aqueous Samples ◽

Sorption Mechanism ◽

Characteristic Parameters ◽

Sorption Characteristic ◽

Natural Mineral ◽

Maximum Sorption Capacity ◽

Ammonium Removal ◽

Maximum Sorption

In this manuscript an improved sorbent based on modified exfoliated carbon nanoplatelets, applied in the removal of ammonium from aqueous samples, is presented. This sorbent showed better efficiency in comparison with the previous one obtained in our group for ammonium removal, the values of the maximum sorption capacity being improved from 10 to 12.04 mg/g. In terms of kinetics and sorption characteristic parameters, their values were also improved. Based on these results, a sorption mechanism was proposed, taking into account ion-exchange and chemisorption processes at the surface of the oxidized exfoliated carbon nanoplatelets. Future applications for simultaneous removal of other positive charged contaminants from natural waters might be possible.

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