Влияние способа сильного легирования на композиционную однородность и оптические свойства монокристаллов LiNbO-=SUB=-3-=/SUB=- : Mg

Raman spectroscopy, laser conoscopy and photoinduced light scattering methods have been applied to comparatively study composition uniformity of strongly doped LiNbO3 crystals with a magnesium concentration close to a threshold value ≈5 mol% MgО, grown from a charge synthesized using precursor Nb2O5:Mg (homogeneous doping method) and at direct addition of magnesium to the melt (direct doping method). It has been shown that application of homogeneous doping method allows one to obtain compositionally more homogeneous heavily doped LiNbO3:Mg crystal than direct melt doping method.

Use of Clay Minerals to Control Radioactive Cesium Leaching from Municipal Solid Waste Incineration Ash in Fukushima Prefecture in Summer and Winter

Radioactive cesium (r-Cs) released from the 2011 Fukushima Daiichi Nuclear Power Plant attaches to vegetation/soil and is collected as municipal solid waste (MSW) for incineration, being concentrated in incineration ash (bottom ash [BA], fly ash [FA], and chelate-treated FA [TFA]). r-Cs in FA and TFA can easily leach upon contact with moisture. It is important to prevent further contamination, as r-Cs has negative effects on ecosystems and the human body. Naturally available clay minerals, considered effective for capturing r-Cs, are a good alternative. Here, we sampled ash from MSW incineration facilities in Fukushima in August 2016 and February 2017. We used energy dispersive X-ray fluorescence spectroscopy and Ge semiconductor detector to determine elemental composition and r-Cs concentration in the samples and conducted leaching tests. We also determined the extent of leaching suppression by zeolite, acidic clay, and vermiculite. Chloride contents and r-Cs leaching rates were higher in FA and TFA than in BA, regardless of the season. Prior direct addition and mixing of clay minerals (5 to 20 wt.%) effectively prevented r-Cs leaching. This study is the first to examine r-Cs leaching inhibition by clay mineral direct addition and mixing to MSW incineration ash.

Direct addition of poly-lysine or poly-ethylenimine to the medium, a simple alternative to plate pre-coating

For most cell culture experiments, it is indispensable that the cells are firmly anchored to the culture plates, tolerating several rinsing steps, and withstanding shear forces or temperature changes without detaching. For semi-adherent cells such as the very common HEK 293 cells, this could so far be obtained only by time-consuming plate pre-coating with cationic polymer solutions. We report here, that i) pre-coating with the cheaper poly-ethylenimine (PEI) works as well as the commonly used poly-D-lysine (PDL), but more importantly and novel ii) that simple direct addition of either PEI (1.5 µg/ml) or PDL (2 µg/ml) to the cell culture medium results in strongly anchored HEK 293 cells, indistinguishable from ones seeded on pre-coated plates. Therefore, the replacement of plate pre-coating by direct addition of either PEI or PDL gives comparable excellent results, but is highly labour-, time-, and cost-efficient. Interestingly, additional experiments in this context showed that strong cell attachment requires only cationic polymers but not fetal calf serum added to the medium. Fetal calf serum is, however, of course required for further maintenance and growth of the cells.

Using silver nanoparticles for the increase of YAG: Ce luminescence

In this study, silver nanoparticles with an average diameter of 50-70 nm were synthesized by the chemical reduction method. Subsequently, nanoparticles in different concentrations were introduced into the YAG: Ce luminescent powder synthesized by the method of two-stage coprecipitation into hexamine. The luminescence of samples with different contents of nanosilver was investigated. It was shown that the direct addition of nanosilver to YAG: Ce significantly impairs luminescence. Upon calcination at 900 °C, an increase in the luminescence of the YAG: Ce samples with silver nanoparticles was observed; however, the luminescence intensity was lower than that of the reference sample (without nanosilver). After calcination in an inert atmosphere at a temperature of 1550 °C, a significant increase in the luminescence intensity (of the order of 30-40 %) of the samples with the addition of a nanosilver was observed in comparison with the reference sample. Thus, silver nanoparticles can be successfully used to improve the YAG: Ce phosphors.

Cationic Iridium/Chiral Bidentate Phosphoramidite Catalyzed Asymmetric Hydroarylation

In this personal account, we summarize our investigations on the asymmetric direct addition of C(sp2)-H bond to unsaturated compounds such as C=O, C=C using cationic Iridium-chiral O-linked bidentatephosphoramidite (Me-BIPAM) and S-linked bidentatephosphoramidite (S-Me-BIPAM) catalyst system.

Rapid, reliable, and cheap point-of-care bulk testing for SARS-CoV-2 by combining hybridization capture with improved colorimetric LAMP (Cap-iLAMP)

Here we present a step-by-step protocol for Cap-iLAMP (capture and improved ‎loop-mediated isothermal amplification) which combines a hybridization capture-based RNA extraction of gargle lavage samples with an improved colorimetric RT-LAMP assay and smartphone-based color scoring. Cap-iLAMP is compatible with point-of-care testing and enables the detection of SARS-CoV-2 positive samples in less than one hour. The sensitivity is 97% and the specificity is 99%. In contrast to direct addition of the sample to improved LAMP (iLAMP), Cap-iLAMP prevents false positives and allows single positive samples to be detected in pools of 25 negative samples.

Graphene oxide/silver nanoparticle ink formulations rapidly inhibit influenza A virus and OC43 coronavirus infection in vitro

Respiratory tract infections present a significant risk to the human population, both through seasonal circulation and novel introductions with pandemic potential. There is a strong need for antiviral compounds with broad antimicrobial activity that can be coated onto filtration systems and personal protective equipment to augment their ability to remove infectious particles from the environment. Graphene oxide and silver nanoparticles are both materials with documented antimicrobial properties. Here, we tested the in vitro antiviral properties of several graphene oxide–silver nanoparticle composite materials, which were prepared through three different methods: reduction with silver salt, direct addition of silver nanospheres, and direct addition of silver nanospheres to thiolized graphene. These materials were tested over short time scales for their antiviral activity against two enveloped RNA viruses, influenza A virus and OC43 coronavirus, by performing viral plaque assays after exposure of the viruses to each material. It was found that the graphene oxide – silver nanoparticle materials generated by direct addition of the silver nanospheres were able to completely inhibit plaque formation by both viruses within one minute of exposure. Materials generated by the other two methods had varying levels of efficacy against influenza A virus. These studies indicate that graphene oxide-silver nanoparticle composite materials can rapidly neutralize RNA viruses and demonstrate their potential for use in a wide range of applications.Abstract Figure

Open-source RNA extraction and RT-qPCR methods for SARS-CoV-2 detection

Re-opening of communities in the midst of the ongoing COVID-19 pandemic has ignited new waves of infections in many places around the world. Mitigating the risk of reopening will require widespread SARS-CoV-2 testing, which would be greatly facilitated by simple, rapid, and inexpensive testing methods. This study evaluates several protocols for RNA extraction and RT-qPCR that are simpler and less expensive than prevailing methods. First, isopropanol precipitation is shown to provide an effective means of RNA extraction from nasopharyngeal (NP) swab samples. Second, direct addition of NP swab samples to RT-qPCRs is evaluated without an RNA extraction step. A simple, inexpensive swab collection solution suitable for direct addition is validated using contrived swab samples. Third, an open-source master mix for RT-qPCR is described that permits detection of viral RNA in NP swab samples with a limit of detection of approximately 50 RNA copies per reaction. Quantification cycle (Cq) values for purified RNA from 30 known positive clinical samples showed a strong correlation (r2 = 0.98) between this homemade master mix and commercial TaqPath master mix. Lastly, end-point fluorescence imaging is found to provide an accurate diagnostic readout without requiring a qPCR thermocycler. Adoption of these simple, open-source methods has the potential to reduce the time and expense of COVID-19 testing.