The location and morphometry of the thyroid isthmus in adult Korean cadavers

The thyroid isthmus has different measurements in its width, height, and thickness, and its location with respect to the tracheal rings has been inconsistent, among the anatomical literature. This study was performed to clarify the location and morphometric characteristics of the thyroid isthmus. One hundred thyroid isthmuses of adult Korean cadavers (gender 58 males and 42 females, mean age 62.9 years, range 19–94 years) were used for this study. The distances from the inferior border of the cricoid cartilage to the superior and inferior margins of the isthmus were 4.9 ± 3.7 and 20.8 ± 5.8 mm, respectively. The width, height, and thickness of the thyroid isthmus were 11.1 ± 6.2, 15.9 ± 5.8 and 3.4 ± 1.7 mm, respectively. The thyroid isthmus was located on the 2nd to 4th, 1st to 3rd, and 1st to 4th tracheal rings, in 22, 18 and 18 % of the specimens, respectively. These results are expected to further the current knowledge of the location and morphometry of the thyroid isthmus and provide helpful information for surgical procedures in this region.     

Highly crystalline nickel hexacyanoferrate as a long-life cathode material for sodium-ion batteries

Prussian blue analogs (PBAs) are attractive cathode candidates for high energy density, including long life-cycle rechargeable batteries, due to their non-toxicity, facile synthesis techniques and low cost. Nevertheless, traditionally synthesized PBAs tend to have a flawed crystal structure with a large amount of [Fe(CN)₆]⁴⁻ openings and the presence of crystal water in the framework; therefore the specific capacity achieved has continuously been low with poor cycling stability. Herein, we demonstrate low-defect and sodium-enriched nickel hexacyanoferrate nanocrystals synthesized by a facile low-speed co-precipitation technique assisted by a chelating agent to overcome these problems. As a consequence, the prepared high-quality nickel hexacyanoferrate (HQ-NiHCF) exhibited a high specific capacity of 80 mA h g⁻¹ at 15 mA g⁻¹ (with a theoretical capacity of ∼85 mA h g⁻¹), maintaining a notable cycling stability (78 mA h g⁻¹ at 170 mA g⁻¹ current density) without noticeable fading in capacity retention after 1200 cycles. This low-speed synthesis strategy for PBA-based electrode materials could be also extended to other energy storage materials to fabricate high-performance rechargeable batteries.

A low-speed synthesis strategy was designed to fabricate Prussian blue analog based electrode materials for high-performance rechargeable batteries.     

Distinguishing between halogenated alkanes containing the same halogen based on the reaction kinetic parameter using negative ion mobility spectrometry at atmospheric pressure

Electron adsorption ionization ion mobility spectrometry can be used to detect halogen-containing volatile organic compounds with high sensitivity. However, this traditional electron attachment detection method cannot distinguish between volatile organic compounds containing the same halogen. For different organic compounds containing the same halogen, the product ions formed by the dissociation electron attachment process are the same. In this article, we propose a novel negative corona discharge ion mobility spectrometry method to distinguish between and detect halogenated alkanes containing the same halogen according to the different electron attachment rates and reaction kinetic parameters of the different halogenated alkanes. Although these halogenated alkanes, which contain the same halogen, produce the same type of ions through the electron attachment process, their electron attachment rates are different from each other. In this work, the kinetic information is used as the fingerprint information for the tested samples to distinguish different halogenated alkanes. Five halogenated alkanes were successfully detected using this method. The results show that the method based on the electron attachment rate constant is feasible for the determination of halogenated alkanes containing the same halogen.

Electron attachment ionization ion mobility spectrometry can be used to detect halogen-containing volatile organic compounds with high sensitivity.     

Development of a tablet PC-based portable device for colorimetric determination of assays including COVID-19 and other pathogenic microorganisms

There has been a strong and urgent demand to diagnose community transmission-driven coronavirus disease 2019 (COVID-19) after it crossed borders. A large number of rapid and accurate tests and diagnoses are required at drive-through test stations, community clinics and hospitals. Isothermal amplification technology, such as loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA), provides excellent alternatives for resource limited test environments. LAMP has been shown to be comparable with polymerase chain reaction (PCR) and can be performed in less than 30 min by non-laboratory staff without ribonucleic acid (RNA) extractions commonly associated with PCR. LAMP tests on assays with SARS-CoV-2 and other pathogenic microorganisms, such as Dengue, Malaria, and Influenza viruses and Helicobacter pylori show color changes allowing test results to be interpreted by the color change of the assays. However, visual inspection of a large number of assays is prone to human error and manual record keeping makes test result tracking for an epidemiologic investigation very difficult and inefficient. The epidemiologic investigation is an essential part of the fight against community transmission-driven viruses. We have developed a very accurate and reliable, human error free, tablet PC-based portable device for colorimetric determination of assays including SARS-CoV-2 and other pathogenic microorganisms.

There has been a strong and urgent demand to diagnose community transmission-driven coronavirus disease 2019 (COVID-19) after it crossed borders. Tablet PC-based portable device for colorimetric determination and 3D printed sample holders.     

Anti-flammability,mechanical and thermal properties of bio-based rigid polyurethane foams with the addition of flame retardants

Adding efficient and environmentally friendly flame retardants to polyurethane foams is the preferable way to improve their flame resistance ability. In this work, bio-based rigid polyurethane foams (RPUFs) were prepared with the addition of dicyclohexyl aluminium hypophosphate (DAH) or aluminium diethyl phosphinate (ADP) as the flame retardant. The mechanical properties, thermal degradation and flammability behavior of the obtained RPUFs were evaluated by means of compressive strength tests, thermogravimetry analysis, vertical burning test and scanning electron microscopes. The characterization results indicate that, with the same content of flame retardant, the compressive strength at the deformation of 10% for each RPUF prepared with the addition of DAH is higher than that of the foams with ADP addition, which fully meets the specifications for building insulation materials. Moreover, the average flame height of each RPUF with the addition of flame retardants is less than 250 mm, whereas the average burning time of RPUF with 15 wt% addition of DAH is only 4.4 s, far less than that (12.5 s) of the foam with the same addition amount of ADP. The RPUFs with DAH addition have the potential advantages for thermal insulation applications in various fields.

Bio-based rigid polyurethane foams with the addition of flame retardant exhibit preferable flame-retardant properties.     

Application of hyperspectral imaging for spatial prediction of soluble solid content in sweet potato

Visible and near infrared (Vis-NIR) hyperspectral imaging was used for fast detection and visualization of soluble solid content (SSC) in ‘Beijing 553’ and ‘Red Banana’ sweet potatoes. Hyperspectral images were acquired from 420 ROIs of each cultivar of sliced sweet potatoes. There were 8 and 10 outliers removed from ‘Beijing 553’ and ‘Red Banana’ sweet potatoes by Monte Carlo partial least squares (MCPLS). The optimal spectral pretreatments were determined to enhance the performance of the prediction model. Successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) were employed to select characteristic wavelengths. SSC prediction models were developed using partial least squares regression (PLSR), support vector regression (SVR) and multivariate linear regression (MLR). The more effective prediction performances emerged from the SPA–SVR model with R_p² of 0.8581, RMSEP of 0.2951 and RPD_p of 2.56 for ‘Beijing 553’ sweet potato, and the CARS–MLR model with R_p² of 0.8153, RMSEP of 0.2744 and RPD_p of 2.09 for ‘Red Banana’ sweet potato. Spatial distribution maps of SSC were obtained in a pixel-wise manner using SPA–SVR and CARS–MLR models for quantifying the SSC level in a simple way. The overall results illustrated that Vis-NIR hyperspectral imaging was a powerful tool for spatial prediction of SSC in sweet potatoes.

Visible and near infrared (Vis-NIR) hyperspectral imaging was used for fast detection and visualization of soluble solid content (SSC) in ‘Beijing 553’ and ‘Red Banana’ sweet potatoes.     

Two 3D Mn-based coordination polymers: synthesis,structure and magnetocaloric effect

Two three-dimensional (3D) coordination polymers, namely Mn^II₆(CH₃COO)₂(HCOO)₂(IN)₈(C₄H₈O)₂(H₂O) and Mn^III₆Mn^II₁₂(μ₃-O)₆(CH₃COO)₁₂(IN)₁₈(H₂O)_7.5 (abbreviated as Mn^II₆ and Mn^II₁₂Mn^III₆ respectively; HIN = isonicotinic acid), were synthesized by the reaction of Mn(CH₃COO)₂·4H₂O and isonicotinic acid under solvothermal conditions. Magnetic studies revealed that antiferromagnetic interactions may be present in compounds Mn^II₆ and Mn^II₁₂Mn^III₆. Moreover, the values of −ΔS_m (26.27 (Mn^II₆) and 37.69 (Mn^II₁₂Mn^III₆) J kg⁻¹ K⁻¹ at ΔH = 7 T) are relatively larger than those of the reported Mn-based coordination polymers. This work provides a great scope in the magnetocaloric effect (MCE) of pure 3d-type systems.

Two 3D coordination polymers (Mn^II₆ and Mn^II₁₂Mn^III₆) were synthesized. Magnetic studies revealed that they are potential magnetic materials.     

Synthesis of MOFs/GO composite for corrosion resistance application on carbon steel

Two unreported metal–organic frameworks [Cu(6-Me-2,3-pydc)(1,10-phen)·7H₂O]_n (namely Cu-MOF) and [Mn₂(2,2′-bca)₂(H₂O)₂]_n (namely Mn-MOF) were synthesized by a solvothermal method and their structures were characterized and confirmed by elemental analysis, X-ray single crystal diffraction, Fourier infrared spectroscopy and thermogravimetric analysis. Cu-MOF/graphene (Cu-MOF/GR), Cu-MOF/graphene oxide (Cu-MOF/GO), Mn-MOF/graphene (Mn-MOF/GR) and Mn-MOF/graphene oxide (Mn-MOF/GO) composite materials were successfully synthesized by a solvothermal method and characterized and analyzed by PXRD, SEM and TEM. In order to study the corrosion inhibition properties of the Cu-MOF/GR, Cu-MOF/GO, Mn-MOF/GR and Mn-MOF/GO composite materials on carbon steel, they were mixed with waterborne acrylic varnish to prepare a series of composite coatings to explore in 3.5 wt% NaCl solution by electrochemical measurements and results showed that the total polarization resistance of the 3% Cu-MOF/GO and 3% Mn-MOF/GO composite coatings on the carbon steel surface were relatively large, and were 55 097 and 55 729 Ω cm², respectively, which could effectively protect the carbon steel from corrosion. After immersion for 30 days, the 3% Mn-MOF/GO composite still maintained high corrosion resistance, the |Z| values were still as high as 23 804 Ω cm². Therefore, MOFs compounded with GO can produce a synergistic corrosion inhibition effect and improve the corrosion resistance of the coating; this conclusion is well confirmed by the adhesion capability test.

Two unreported metal–organic frameworks [Cu(6-Me-2,3-pydc)(1,10-phen)·7H₂O]_n (namely Cu-MOF) and [Mn₂(2,2′-bca)₂(H₂O)₂]_n (namely Mn-MOF) were synthesized and characterized. Cu-MOF and Mn-MOF all can form a three-dimensional structure.     

Green and facile edge-oxidation of multi-layer graphene by sodium persulfate activated with ferrous ions

Effective edge oxidation of graphene with high structural integrity is highly desirable yet technically challenging for most practical applications. In this work, we have developed a green and facile strategy to obtain edge-oxidized graphene with good dispersion stability and high electrical conductivity by exploiting high edge reactivity of highly conductive multi-layer graphene and oxidizing radicals (SO₄⁻˙) generated from sodium persulfate (Na₂S₂O₈) with ferrous ion (Fe²⁺) activation. Owing to high structural integrity of pristine graphene and effective edge oxidation, the obtained edge-oxidized graphene exhibited excellent dispersion stability and satisfactory electrical conductivity (i.e. ≥240 S cm⁻¹). Moreover, the oxidation degree of pristine graphene can be well controlled by adjusting treatment time. The obtained edge-oxidized graphene is expected to find a variety of applications in many fields of anti-static films, energy storage materials, flexible sensors and high-performance nanocomposites.

A green and facile strategy is represented to obtain edge-oxidized graphene by exploiting sulfate radicals generated from Na₂S₂O₈ with Fe²⁺ activation.