AVASCULAR NECROSIS OF THE FEMORAL HEAD – NOT TO BE OVERLOOKED SEQUELA AFTER COVID 19 INFECTION

BackgroundCOVID 19 infection could lead to different sequelae in survivors, known as post-COVID or long COVID 19 syndromes. Some of them are thought to be due to the thrombophylic changes observed in COVID 19 infection, but some are thought to be caused by the administrated (especially high dose) corticosteroid treatment. Avascular necrosis of the femoral head (AVNFH) is a multifactorial disease which leads to compromised vascular supply, ischemia and finally necrosis of the femoral head. As corticosteroids usage and thrombophylic states are among the main known risk factors for the development AVNFH [1], it could be presumed that the frequency of this disease will increase with the COVID 19 pandemic. The exact corticosteroid dose needed for the development of AVNFH is not clear, but it has been stated that a higher daily dose and a larger total cumulative dose increase substantially the risk for the development of osteonecrosis [2].ObjectivesTo describe in detail the characteristics of AVNFH diagnosed in patients after COVID 19 infection.MethodsThe study was done in a tertiary university rheumatological clinic. Data was extracted from the records of patients who have been referred to the clinic because of hip pain between June and December 2022. Inclusion criteria were: - a new onset of uni-or bilateral hip pain that started after a documented COVID 19 infection;and an MRI scan of the hip joints showing osteonecrosis of one or both femoral heads. Exclusion criteria were the presence of hip pain prior to the COVID 19 infection, anamnesis of traumatic injuries of the hips or pelvis, personal history of hypercoagulable states.ResultsNine patients (4 women and 5 men) with an average age 59.1 years (range 38-72) were included in the study. Four patients had been diagnosed with bilateral and five – with unilateral AVNFH, thus 13 hip joints were analysed in total (8 left and 5 right sided). The mean time lap between the COVID 19 infection and the start of the hip pain was 26.2 weeks (range 10-48 weeks). All patients had limited and painful movement in their symptomatic hip(s), especially internal rotation and four of the patients had also elevated CRP levels (mean 11.7 mg/L). The stage of the AVNFH was evaluated according to the Ficat-Arlet classification (0-IV stage). In four hips the AVNFH was stage I, five hips were classified as stage II and the remaining four joints - as stage III. All symptomatic hip joints exhibited effusion/synovitis on both ultrasound examination and the corresponding MRI scan. It should be noted that the presence of hip effusion was found to be related with a worse prognosis in AVNFH [1]. In three patients the amount of the effusion required arthrocentesis and fluid aspiration. The analysis of the joint fluid was consistent with a degenerative disease (i.e., low WBC count with predominant lymphocytes and no crystals). All patients included in our study had received corticosteroids during their COVID19 infection, while 6 of the patients had also been hospitalized due to more severe disease. According to the patients' documentation, the mean cumulative dose of the received corticosteroids was 936.2 mg prednisolone equivalent per patient (range 187-2272 mg).ConclusionAVNFH must not be overlooked in a new onset hip pain after COVID 19 infection. Our results show that corticosteroids administrated during the infection and the presence of hip joint effusion on ultrasound are especially suggestive for the development of osteonecrosis, as they were registered in all of our patients. The presence of these two factors necessitates patient referral for an MRI scan of the hips, in order that AVNFH be detected timely.References[1]Petek D, Hannouche D, Suva D. Osteonecrosis of the femoral head: pathophysiology and current concepts of treatment. EFORT Open Rev. 2019 Mar 15;4(3):85-97.[2]Kerachian MA, Séguin C, Harvey EJ. Glucocorticoids in osteonecrosis of the femoral head: a new understanding of the mechanisms of action. J Steroid Biochem Mol Biol. 2009 Apr;114(3-5):121-8.Acknowledgements:NIL.Disclosur of InterestsPLAMEN TODOROV Speakers bureau: speaker at national level for AbbVie, Novartis and UCB, Lily Mekenyan: None declared, Anastas Batalov Speakers bureau: Speaker at national level for AbbVie, Novartis, Pfizer, Stada, Elly Lilly.

A selectivity-enhanced colloidal crystal array for ribavirin sensing based on the synergistic effect of covalent and non-covalent interactions

Ribavirin is an important antiviral with demonstrated activity against coronaviruses such as severe acute respiratory syndrome coronavirus and coronavirus disease 2019 virus. However, abuse of ribavirin will cause great environmental damage and threaten human health owing to its reproductive toxicity and teratogenicity. Therefore, an innovative detection method is demanded for simple and sensitive detection of ribavirin. This work reports an imprinted colloidal crystal array (ICCA) for ribavirin sensing. The building blocks of the ICCA are ribavirin imprinted spheres, which possess superior binding efficiency toward ribavirin. Benefiting from the highly ordered structure, the ICCA exhibits optical properties which change upon binding ribavirin. The changes in reflectance wavelength enable a fast and label-free detection of ribavirin between 21 and 245 μmol L−1. Moreover, the sensor shows excellent selectivity for ribavirin detection in river water. Overall, all the results reported in this work demonstrate that the ICCA should be a promising detection tool for antivirals. © 2023 Society of Industrial Chemistry. © 2023 Society of Industrial Chemistry.

Structural and Computational Studies of Cobalt(II) and Copper(II) Complexes with Aromatic Heterocyclic Ligand

Two coordination complexes, a cobalt(II) complex tris(1,10-phenanthroline)-cobalt perchlorate hydrate, [Co(phen)3]·(ClO4)2·H2O(1), and a copper(II) complex tris(1,10-phenanthroline)-copper perchlorate 4-bromo-2-{[(naphthalene-1-yl)imino]methyl}phenol hydrate, [Cu(phen)3]·(ClO4)2·HL·[O] (2), [where, phen = 1,10-phenathroline as aromatic heterocyclic ligand, HL = 4-bromo-2-((Z)-(naphthalene-4-ylimino) methyl) phenol] have been synthesized and structurally characterized. Single crystal X-ray analysis of both complexes has revealed the presence of a distorted octahedral geometry around cobalt(II) and copper(II) ions. density functional theory (DFT)-based quantum chemical calculations were performed on the cationic complex [Co(phen)3]2+ and copper(II) complex [Cu(phen)3]2+ to get the structure property relationship. Hirshfeld surface and 2-D fingerprint plots have been explored in the crystal structure of both the metal complexes. To find potential SARS-CoV-2 drug candidates, both the complexes were subjected to molecular docking calculations with SARS-CoV-2 virus (PDB ID: 7BQY and 7C2Q). We have found stable docked structures where docked metal chelates could readily bound to the SARS-CoV-2 Mpro. The molecular docking calculations of the complex (1) into the 7C2Q-main protease of SARS-CoV-2 virus revealed the binding energy of −9.4 kcal/mol with a good inhibition constant of 1.834 µM, while complex (2) exhibited the binding energy of −9.0 kcal/mol, and the inhibition constant of 1.365 µM at the inhibition binding site of receptor protein. Overall, our in silico studies explored the potential role of cobalt(II) complex (1), and copper(II) complex (2) complex as the viable and alternative therapeutic solution for SARS-CoV-2.

Design spherical particles of potassium peroxymonosulfate compound salt with high stability and good powder properties via an agglomeration-dissolution mechanism

With the outbreak of COVID-19, disinfection protection has become a necessary measure to prevent infection. As a new type of disinfectant, potassium peroxymonosulfate compound salt (PMS) has the advantages of good bactericidal effect, non-toxicity, high safety and stability. However, the current PMS products with irregular particle shapes lead to poor flowability, high hygroscopicity, poor stability of reactive oxygen species (ROS) and serious caking problems. In this work, an agglomeration-dissolution mechanism was designed to prepare spherical PMS particles with large size (>300 mm) and high sphericity (up to 90%), effectively addressing the above problems. Shaping (dissolution and abrasion) is the key to improving sphericity, which is mainly controlled by the design of the heating mode, residence time and stirring rate. Compared with the irregular PMS particles, the large spherical particles present better flowability (angle of repose decreased by 35.80%, Carr's index decreased by 64.29%, Hausner's ratio decreased by 19.14%), lower hygroscopicity (decreased by 38.0%), lower caking ratio (decreased by 84.50%), and higher stability (the monthly loss of ROS was reduced by 61.68%). The agglomeration -dissolution mechanism demonstrates the crystallization, agglomeration, dissolution and abrasion pro-cess of inorganic salt crystals, providing an opportunity to prepare high-end inorganic crystal materials with high-quality morphologies.(c) 2022 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Cholesterol and Melatonin Exert Opposite Effects on the Interaction of Model DMPC Membranes with the SARS-CoV-2 S-Protein: A SANS Study

An effect of receptor-binding domain (RBD) of SARS-CoV-2 S-protein on structural parameters of model lipid membranes presented by dimyristoylphosphatidylcholine (DMPC) systems with cholesterol and melatonin impurities is studied by small angle neutron scattering (SANS). It is shown that an increase in melatonin concentration in the lipid membrane leads to a decrease in the thickness of the lipid bilayer, while an increase in the concentration of cholesterol leads to an increase in its thickness. It is suggested that increasing the concentration of melatonin in a membrane prevents the interaction of coronaviral S-protein with a lipid membrane of a cell. In the presence of cholesterol in the system, the interaction of a lipid membrane with an active part of S-protein occurs depending on a phase state of the lipid: in the case of a gel phase, there is no changes in structural parameters, but at higher temperatures in the case of a liquid crystal phase, an addition of RBD SARS-CoV-2 to the system causes a reduce in the membrane thickness. © 2023 Wiley-VCH GmbH.

One-step and wash-free multiplexed immunoassay platform based on bioinspired photonic barcodes

Multiplex, rapid and accurate virus quantification plays a great value in biomedical detection. Here, a novel one step, wash-free immunoassay platform based bioinspired PhC barcodes for multiplexed virus quantification was explored. PhC barcodes were decorated with PDA by self-polymerization of DA, thus this nanocomposite hybridized PhC barcodes facilitated the adsorption of FITC labelled antibodies and quenched itself photoluminescent, allowing a fast responsive composite platform. In the presence of target analyte, the FITC-labelled detection antibody was released from the surface of PDA decorated microcarrier to specifically bind to the target analyte, thus recovered the photoluminescence. In addition, the PhC microcarrier was enabled to carry out various color barcode for different targets detection though tuning internal periodic structures. Based on these excellent performances of the nanocomposite barcode, this method can not only capture H1N1, H5N1, SARS-CoV-2 simultaneously with rapid, accuracy but also accomplish multiplex quantification detection with high-sensitivity. Furthermore, our developed platform was also achieved with high-sensitivity and high-specificity through the verification of clinical samples, thus laying out a new avenue for multiplex virus detection in clinical diagnosis. © 2023

Structure property relationship in two thiazole derivatives: Insights of crystal structure, Hirshfeld surface, DFT, QTAIM, NBO and molecular docking studies

Detailed structural and noncovalent interactions in two thiazole derivatives (N-(4-Bromophenyl)-2-(methylthio)thiazole-5-carboxamide and Ethyl-5-((4-bromophenyl)carbamoyl)thiazole-4-carboxylate) are investigated by single crystal X-ray diffraction study and computational approaches. The structure investigation revealed that various interactions like C-H…O, N-H…O, and N-H…N hydrogen bonds and Br…Br interactions are involved in constructing ring motifs to stabilize the crystal packing. Hirshfeld surface analysis and fingerprint plots were carried out to study the differences and similarities in the relative contribution of noncovalent interactions in both the molecules. The FMOs and other global reactive parameters are analyzed for thiazole derivatives. The strength and nature of weak interactions present in the molecule were characterized by RDG-based NCI and QTAIM analyses. Natural bond orbital (NBO) analysis unravels the importance of non-covalent and hyperconjugative interactions for the stability of the molecules in their solid state. Further, molecular docking of N-(4-Bromophenyl)-2-(methylthio)thiazole-5-carboxamide and Ethyl-5-((4-bromophenyl)carbamoyl)thiazole-4-carboxylate with SARS-Covid-19 have been carried out. © 2023 Taylor & Francis Group, LLC.

Computational study of 2D photonic crystal based biosensor for SARS-COV-2 detection

A computational study to design a 2D-photonic crystal (PC) structure with a fluorescence-based biosensor has been demonstrated for the detection of the severe acute respiratory syndrome corona virus 2 (SARS-COV-2) virus in the lungs. The proposed sensor can detect the different concentrations of the virus without any pretreatment of the sample. The virus detection is performed by measuring the mid-gap wavelength from the dispersion diagram and a redshift in the mid-gap wavelength has been observed as the concentration of virus increases in the lung tissue. The plane wave expansion method is used to determine the dispersion diagram of the proposed PC. The interaction of incident light with the proposed PC-based biosensor has been analyzed to evaluate the shift in the mid-gap wavelength. A maximum sensitivity of about 1459.3 nm/RIU is obtained for r/a = 0.45 with a mid-gap wavelength shift of 145.93 nm at n net = 1.49 concentration of SARS-COV-2. Moreover, a very small detection time has been observed with the proposed device as compared to conventional methods. This study provides a simple process to detect the presence of a virus within a short period and could be helpful in the development of a direct and easy-to-use portable detection kit in the future. © 2023 IOP Publishing Ltd.

Synthesis and crystal characteristics of nirmatrelvir

Several synthetic routes of nirmatrelvir (the ingredient of a new drug to treat COVID-19 made by Pfizer) have been reported. We focused on a second route to improve the synthetic method of nirmatrelvir with a methodology that included different steps. The first step was an analysis of reaction byproducts using acetonitrile as a solvent of the condensation reaction to improve the inversion rate. Then, we used isobutyl acetate as a crystalline solvent to obtain the key intermediate as a solvate, which was a stable crystal product with high purity. Complementarily, we also used trifluoroacetic anhydride as the primary-amide dehydrating agent, and 2-methyl tetrahydrofuran as the solvent to prepare nirmatrelvir, which led to an overall yield of 48% via four steps and a purity of 99.5% according to high-performance liquid chromatography. We also investigated the crystal form of nirmatrelvir: the single-crystal features and transformation from a crystal form to nirmatrelvir were dependent upon temperature. Our data have great value for study of the synthetic method and crystal stability of nirmatrelvir. © 2023 The Royal Society of Chemistry.

Development of a multivariate model with desirability-based optimization for simultaneous determination of five co-administrated drugs for the management of COVID-19 infection in their dosage forms via validated RP-HPLC method

More than 2.9 million people have died as a result of the global demographic impact of the coronavirus illness of 2019 (COVID-19). Numerous antiviral and anti-inflammatory medications have FDA approval to treat COVID-19 patients. For the simultaneous determination of COVID-19 utilized medications (Remdesivir, Moxifloxacin, Dexamethasone, Apixaban, and paracetamol) in their dosage forms, a sensitive technique has been developed and validated. The aforementioned medications were separated and quantified with the help of experimental design. The Box-Behnken design was used in the experiment to optimize the chromatographic method's analytical parameters. It employed RP-HPLC with a UV detector. An INERTSIL ODS-3 C18 column (5 µm, 250 × 4.6 mm) with mobile phase composed of acetonitrile: 30 mmoL potassium dihydrogen phosphate buffer (pH = 7.5) (50:50, v/v), at room temperature was employed to separate the aforementioned drugs. Paracetamol was linear over the concentration range (1–50 µg/mL), Moxifloxacin (5–70 µg/mL), Apixaban (5–70 µg/mL), Dexamethasone (1–100 µg/mL), and Remdesivir (5–100 µg/mL). According to ICH guidelines, the new approach underwent thorough validation. Between the proposed method's results and those from the reference or reported methods, there was no significant difference. The technique is simple to use in research of the cited medications in their dosage forms for quality control aspects.

Effect of Cholesterol on Biomimetic Membrane Curvature and Coronavirus Fusion Peptide Encapsulation.

Biomimetic cubic phases can be used for protein encapsulation in a variety of applications such as biosensors and drug delivery. Cubic phases with a high concentration of cholesterol and phospholipids were obtained herein. It is shown that the cubic phase structure can be maintained with a higher concentration of biomimetic membrane additives than has been reported previously. Opposing effects on the curvature of the membrane were observed upon the addition of phospholipids and cholesterol. Furthermore, the coronavirus fusion peptide significantly increased the negative curvature of the biomimetic membrane with cholesterol. We show that the viral fusion peptide can undergo structural changes leading to the formation of hydrophobic α-helices that insert into the lipid bilayer. This is of high importance, as a fusion peptide that induces increased negative curvature as shown by the formation of inverse hexagonal phases allows for greater contact area between two membranes, which is required for viral fusion to occur. The cytotoxicity assay showed that the toxicity toward HeLa cells was dramatically decreased when the cholesterol or peptide level in the nanoparticles increased. This suggests that the addition of cholesterol can improve the biocompatibility of the cubic phase nanoparticles, making them safer for use in biomedical applications. As the results, this work improves the potential for the biomedical end-use applications of the nonlamellar lipid nanoparticles and shows the need of systematic formulation studies due to the complex interplay of all components.

Cu(II)(PhOMe-Salophen) Complex: Greener Pasture Biological Study, XRD/HAS Interactions, and MEP

Abstract: PhOMe-salophen (1b) (salophen is N,N-bis(salycilidene)-1,2-phenylenediamine with two tert-butyl on each ring) and Cu(II) complex with PhOMe-salophen (1c) have been synthesized and characterized using various tools, including X-ray diffraction for the Cu(II)-complex (1c, C43H52CuN2O3)). The copper complex has been obtained by Cu2+ templated approach using 1b. PhOMe-salophen (1b) has been obtained in reasonably high yield using a mixture of the Schiff-base, 1a, Pd(OAc)2, PPh3, Na2CO3, 4-methoxyphenylboronic acid in benzene. We focus in this research work on the electronic and structural properties of the Cu–Schiff base complex. The tetra-coordinate τ4 index was calculated, indicating almost a perfect square planner in agreement with X-ray diffraction results. MEP reveals the maximum positive regions in 1/-associated with the azomethine and methoxyphenyl C–H bonds with an average value of 0.03 a.u. Hirshfeld surface analysis (HSA) was also studied to highlight the significant inter-atomic contacts and their percentage contribution through 2D Fingerprint plot. In a fair comparative molecular docking study, 1b and 1c were docked together with N-[{(5-methylisoxazol-3-yl)-carbonyl}alanyl}-l-valyl]-N1-((1R,2Z)-4-(benzyloxy)-4-oxo-1-[{(3R)-2-oxopyrrolidin-3-yl}methyl]but-2-enyl)-l-leucinamide, N3 against main protease Mpro, (PDB code 7BQY) using the same parameters and conditions. Interesting here to use the free energy, in silico, molecular docking approach, which aims to rank our molecules with respect to the well-known inhibitor, N3. The binding scores of 1b, 1c, N3 are –7.8, –9.0, and –8.4 kcal/mol, respectively. These preliminary results propose that ligands deserve additional study in the context of possible remedial agents for COVID-19. © 2022, Pleiades Publishing, Ltd.

Synthesis, crystal structure, DFT calculations, and Hirshfeld surface analysis of an NNN pincer type compound

The novel benzamide derivative NNN pincer type, N,N'-(azanediylbis(2,1-phenylene))bis(3-chlorobenzamide) (H3L), was synthesized from bis(2-nitrophenyl)amine starting material. The pincer ligand was characterized by 1H NMR, 13C NMR, COSY, HMQC, and FT-IR techniques. The geometry of pincer ligand was also confirmed by a single-crystal X-ray diffraction analysis. Structural analysis demonstrate that H3L is monoclinic and space group P21/n with Z = 4. It was find out the molecular conformation of the structure is promoted by intramolecular (N[sbnd]H⋅⋅⋅O, N[sbnd]H⋅⋅⋅N, and C[sbnd]H⋅⋅⋅O) and intermolecular (N(2)-H(2)⋅⋅⋅O(2)i, symmetry code (i) = 1/2 + x, 3/2-y, 1/2 + z) hydrogen bonds. The theoretical study of H3L was performed in the gaseous phase by B3LYP/6-311G(d,p) method to determine the structural properties of the title molecule, as a consequence the obtained data showed that the considerable agreement between the experimental and theoretical results. The reactivity and stability of the molecule were evaluated by calculating the HOMO–LUMO energy gap which was found as 6.5163 eV. In addition, FMO, NBO, NLO, DOS, RDG, MEP surface, and Mulliken atomic charge analyses were carried out. Hirshfeld surface analysis and two-dimensional fingerprint plots were investigated and the obtained data exposed that the most significant contributions to the crystal packing are from C···H/H···C (33.2%), H···H (31.5%), and H···Cl/Cl··H (18.9%) contacts. Furthermore, the molecular docking studies were performed to reveal the binding affinity between the title compound and the main protease (6LU7) of COVID-19 coronavirus. © 2023 Elsevier B.V.

Low-Dimensional Compounds Containing Bioactive Ligands. Part XX: Crystal Structures, Cytotoxic, Antimicrobial Activities and DNA/BSA Binding of Oligonuclear Zinc Complexes with Halogen Derivatives of 8-Hydroxyquinoline

Two tetranuclear [Zn4Cl2(ClQ)6]·2DMF (1) and [Zn4Cl2(ClQ)6(H2O)2]·4DMF (2), as well as three dinuclear [Zn2(ClQ)3(HClQ)3]I3 (3), [Zn2(dClQ)2(H2O)6(SO4)] (4) and [Zn2(dBrQ)2(H2O)6(SO4)] (5), complexes (HClQ = 5-chloro-8-hydroxyquinoline, HdClQ = 5,7-dichloro-8-hydroxyquinoline and HdBrQ = 5,7-dibromo-8-hydroxyquinoline) were prepared as possible anticancer or antimicrobial agents and characterized by IR spectroscopy, elemental analysis and single crystal X-ray structure analysis. The stability of the complexes in solution was verified by NMR spectroscopy. Antiproliferative activity and selectivity of the prepared complexes were studied using in vitro MTT assay against the HeLa, A549, MCF-7, MDA-MB-231, HCT116 and Caco-2 cancer cell lines and on the Cos-7 non-cancerous cell line. The most sensitive to the tested complexes was Caco-2 cell line. Among the tested complexes, complex 3 showed the highest cytotoxicity against all cell lines. Unfortunately, all complexes showed only poor selectivity to normal cells, except for complex 5, which showed a certain level of selectivity. Antibacterial potential was observed for complex 5 only. Moreover, the DNA/BSA binding potential of complexes 1–3 was investigated by UV-vis and fluorescence spectroscopic methods.

4-(4-methoxyphenyl)-6-methyl-3-phenyl-4H-1,2,4-oxadiazin-5(6H)-one: Synthesis, crystal structure, Hirshfeld surface analysis, noncovalent, ADMET studies and biological evaluation

Oxadiazines are heterocyclic compounds containing two nitrogen and one oxygen atom in a six-membered ring. The synthesis and crystal structure of 4-(4-methoxyphenyl)-6-methyl-3-phenyl-4H-1,2,4-oxadiazin-5(6H)-one (MPMP-OXA) was reported. The organic crystal structure of the synthesized compound was fully characterized by various spectroscopic techniques (Fourier Transform Infrared Spectroscopy, NMR and LC/MS-TOF) and single-crystal X-ray diffraction studies. The MPMP-OXA crystal structure crystallizes in the triclinic system and space group P-1 with a = 5.9395(15) Å, b = 11.471(3) Å, c = 11.901(3) Å, α = 70.075(4)°, β = 83.454(4)°, γ = 78.016(4)°, V = 744.9(3) Å3, Z = 2 cell parameters. This work is aimed to study the weak interactions in the crystal packing of a new synthesized oxadiazine derivate. The contributions of the most important intermolecular interactions in the crystal structure were investigated by 3D-Hirshfeld surface (HS) and 2D-fingerprint analysis. The C[sbnd]H···O interactions as the most important contributors to the crystal packing between the oxygen of the oxadiazine ring and the hydrogen atom of phenyl ring appear as bright red spots visible on the HS surface. The hydrogen-bonded interaction of MPMP-OXA has been investigated using noncovalent interactions approach. The molecular docking studies for the synthesized compound were performed to gain insight into the inhibition nature of this molecule against DNA Gyrase B Candida and 3-chymotrypsin-like protease (SARS-CoV main protease) proteins and resulted in good activities for new anti-agents. Lastly, Bioavailability, druggability as well as absorption, distribution, metabolism, excretion, and toxicity parameters (ADMET), and gastrointestinal absorption (BOILED-Egg method) properties of newly synthesized compound using smile codes were performed in detail. © 2023 Elsevier B.V.

Czochralski (CZ) process modification with cooling tube in the response to market Global silicon shortage

Recently, the silicon wafer producers, affected by Covid-19 and USA-China competition, looks for new production processes to increase the production. On the other hand, the common parts of CZ puller such as heater, crucible and thermal shield are optimized over time and now the common CZ process is reached to limitation for further improvement. Here, we propose a modified CZ method by adding a cooling tube into the growth zone. The new proposed Cz method is applied to the 8″ crystal growth process. A fully 3D transition model including energy equation, Navier–Stokes equation, surface-to-surface radiation heat transfer, moving mesh and thermal stress equations is implemented. The simulation is performed for both original and new CZ method. It was proved that the new CZ method increases the pulling speed up to 25 %. To ensure about the crystal quality, the thermal stress is compared between original and new proposed CZ method. Although it was found that the thermal stress increases about twice but still the maximum von Mises stress never exceeds the critical value 25 MPa. Additionally, the power consumption is also found to enhance maximum 2 kW under new conditions. To evaluate the model the interface and heater power for the original CZ puller is compared with industrial CZ process and it shows acceptable accuracy. © 2023 Elsevier B.V.

Comparison of oxidative stress response of in vitro retinal cells exposed to blue light from emissive versus reflective displays

During COVID-19, there was increased use of handheld displays in educational settings. There is growing concern that eye health may be affected by prolonged exposure to the light-emitting diodes used as frontlights or backlights in handheld displays. The potential impact of light exposure from tablet-sized devices with different display technologies and various spectral outputs was assessed in an in vitro model using human retinal epithelial (ARPE-19) cells. Cellular response was quantified by measuring reactive oxidative species (ROS) and by analyzing mitochondrial morphology. Control experiments established a baseline ROS response to hazardous blue light exposure and also that red light resulted in no detectable ROS response. Under identical conditions, ROS response increased with time for all devices. However, different device spectra caused ROS to accumulate at different rates. When operating the devices in the same mode (day or night), cells accumulated ROS two to three times more slowly on exposure to frontlit electronic paper displays compared to backlit liquid crystal displays. With increasing ROS accumulation, mitochondrial morphology shifted from elongate interconnected features typically observed under normal conditions to rounded disconnected features associated with oxidative stress response. © 2023 E Ink Corporation. Journal of the Society for Information Display published by Wiley Periodicals LLC on behalf of Society for Information Display.

At-Home COVID-19 Rapid Antigen Test Down to 0.03 pg mL-1 of Nucleocapsid Protein.

Rapid and ultra-sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for early screening and management of COVID-19. Currently, the real-time reverse transcription polymerase chain reaction (rRT-PCR) is the primary laboratory method for diagnosing SARS-CoV-2. It is not suitable for at-home COVID-19 diagnostic test due to the long operating time, specific equipment, and professional procedures. Here an all-printed photonic crystal (PC) microarray with portable device for at-home COVID-19 rapid antigen test is reported. The fluorescence-enhanced effect of PC amplifies the fluorescence intensity of the labeled probe, achieving detection of nucleocapsid (N-) protein down to 0.03 pg mL-1 . A portable fluorescence intensity measurement instrument gives the result (negative or positive) by the color of the indicator within 5 s after inserting the reacted PC microarray test card. The N protein in inactivated virus samples (with cycle threshold values of 26.6-40.0) can be detected. The PC microarray provides a general and easy-to-use method for the timely monitoring and eventual control of the global coronavirus pandemic.

A photonic resonator interferometric scattering microscope for label-free detection of nanometer-scale objects with digital precision in point-of-use environments.

Label-free detection and digital counting of nanometer-scaled objects such as nanoparticles, viruses, extracellular vesicles, and protein molecules enable a wide range of applications in cancer diagnostics, pathogen detection, and life science research. Here, we report the design, implementation, and characterization of a compact Photonic Resonator Interferometric Scattering Microscope (PRISM) designed for point-of-use environments and applications. The contrast of interferometric scattering microscopy is amplified through a photonic crystal surface, upon which scattered light from an object combines with illumination from a monochromatic source. The use of a photonic crystal substrate for interferemetric scattering microscopy results in reduced requirements for high-intensity lasers or oil-immersion objectives, thus opening a pathway toward instruments that are more suitable for environments outside the optics laboratory. The instrument incorporates two innovative elements that facilitate operation on a desktop in ordinary laboratory environments by users that do not have optics expertise. First, because scattering microscopes are extremely sensitive to vibration, we incorporated an inexpensive but effective solution of suspending the instrument's main components from a rigid metal framework using elastic bands, resulting in an average of 28.7 dBV reduction in vibration amplitude compared to an office desk. Second, an automated focusing module based on the principle of total internal reflection maintains the stability of image contrast over time and spatial position. In this work, we characterize the system's performance by measuring the contrast from gold nanoparticles with diameters in the 10-40 nm range and by observing various biological analytes, including HIV virus, SARS-CoV-2 virus, exosome, and ferritin protein.

Teaching Single Crystal X-ray Crystallography in the Undergraduate Classroom with Sugar and Epsom Salt

We developed a single crystal X-ray crystallography experiment based on the crystal structure of sucrose (table sugar), and a more challenging experiment using Epsom salt. Both crystals are readily available in X-ray quality crystalline form. In these experiments, students mounted a crystal on a MiTeGen loop and analyzed it using a Rigaku XtaLAB Mini diffractometer (built 2011). Students generated models of both compounds using CrysAlisPro, Olex2, SHELXT, and SHELXL. All aspects of this experiment use free software programs which have user-friendly interfaces. A step-by-step laboratory protocol for determining the structure of both compounds is included in the Supporting Information. These experiments were used in the Fall of 2019 at the Junior and the Senior level. In the Summer of 2020, a take-home version of the lab was created in response to the Novel 2019 Coronavirus (COVID-19) pandemic and implemented in the General Chemistry laboratory curriculum;this experiment was used for the duration of the 2020-2021 academic year. These experiments are suitable for all undergraduate experience levels. © 2022 American Chemical Society and Division of Chemical Education, Inc.