A portable, rapid isothermal amplification kit enabling naked eye detection of SARS-CoV-2 RNAs.

Since the coronavirus disease 2019 (COVID-19) pandemic, isothermal amplification techniques have attracted attention due to their higher sensitivity and specificity, compared with immunoassays, and their potential application for point-of-care testing (POCT). A requirement of isothermal amplification-based POCT kits is the inclusion of a heating source with an electrical power supply. We developed an amplification-based rapid kit, which is a portable and naked eye-detectable reverse transcriptase (RT)-recombinase polymerase amplification (RPA) kit.

Rapid PCR kit: lateral flow paper strip with Joule heater for SARS-CoV-2 detection.

Polymerase chain reaction (PCR)-based diagnostic kits for point-of-care (POC) testing are highly desirable to prevent the spread of infectious diseases. Here, we demonstrate a rapid PCR testing kit that involves integrating a lateral flow paper strip with a nichrome-based thin film heater. The use of a paper membrane as a PCR-solution container results in fast thermocycling without a cooler because the membrane can contain the solution with a high specific surface area where Joule heating is applied.

Molecular Damage Detection in an Elastomer Nanocomposite with a Coumarin Dimer Mechanophore.

Molecular force probes that generate optical responses to critical levels of mechanical stress (mechanochromophores) are increasingly attractive tools for identifying molecular sites that are most prone to failure. Here, a coumarin dimer mechanophore whose mechanical strength is comparable to that of the sulfur-sulfur bonds found in vulcanized rubbers is reported. It is further shown that the strain-induced scission of the coumarin dimer within the matrix of a particle-reinforced polybutadiene-based co-polymer can be detected and quantified by fluorescence spectroscopy, when cylinders of the nanocomposite are subjected to unconstrained uniaxial stress.

Label-Free Direct Detection of Saxitoxin Based on a Localized Surface Plasmon Resonance Aptasensor.

Seafood is an emerging health food, and interest in improving the quality of seafood is increasing. Saxitoxin (STX) is a neurotoxin produced by marine dinoflagellates that is accumulated in seafood. It can block the neuronal transmission between nerves and muscle cell membranes, resulting in the disturbance of neuromuscular transmission and subsequent voluntary muscle paralysis.

An optical fiber-based LSPR aptasensor for simple and rapid in-situ detection of ochratoxin A.

Label-free biosensing methods that rely on the use of localized surface plasmon resonance (LSPR) have attracted great attention as a result of their simplicity, high sensitivity, and relatively low cost. However, in-situ analysis of real samples using these techniques has remained challenging because colloidal nanoparticles (NPs) can be unstable at certain levels of pH and salt concentration. Even in the case of a chip-type LSPR sensor that can resolve the instability problem by employing NPs immobilized on the substrate, loading of a sample to sensor chip with exact volume control can be difficult for unskilled users.

The Mechanical Strength of a Mechanical Bond: Sonochemical Polymer Mechanochemistry of Poly(catenane) Copolymers.

Topological molecular connections and structures, including physical entanglements in polymer networks, knots along polymer chains, and rotaxanes in sliding ring gels, have important consequences for the physical properties of polymeric materials. Often these topologies contribute through their ability to bear mechanical stress, but experimental measures of their relative mechanical strength are rare. Here, we use sonochemical polymer mechanochemistry to assess the relative mechanical strength of a multicatenane copolymer relative to copolymers of cyclic and linear analogs.

Relative Mechanical Strengths of Weak Bonds in Sonochemical Polymer Mechanochemistry.

The mechanical strength of scissile chemical bonds plays a role in material failure and in the mechanical activation of latent reactivity, but quantitative measures of mechanical strength are rare. Here, we report the relative mechanical strength of polymers bearing three putatively "weak" scissile bonds: the carbon-nitrogen bond of an azobisdialkylnitrile (<30 kcal mol(-1)), the carbon-sulfur bond of a thioether (71-74 kcal mol(-1)), and the carbon-oxygen bond of a benzylphenyl ether (52-54 kcal mol(-1)). The mechanical strengths are assessed in the context of chain scission triggered by pulsed sonication of polymer solutions, by using two complementary techniques: (i) the competition within a single polymer chain between the bond scission of interest and the nonscissile mechanochemical ring opening of gem-dichlorocyclopropane mechanophores and (ii) the molecular weights at long (4 h) sonication times of multimechanophore polymers.

A novel allylic transfer reaction of chirally modified 2-borylbutadiene: synthesis of chiral homoallenyl alcohols.

An enantioselective synthesis of the homoallenyl alcohols was achieved from the reaction of chiral 2-borylbutadiene with aldehydes through an allylic transfer reaction in good yields and enantioselectivities.

Cytokine responses induced by Mycobacterium tuberculosis in patients with HIV-1 infection and tuberculosis.

Objective: Tuberculosis (TB) is an important opportunistic infection in HIV patients. Immune responses to Mycobacterium tuberculosis in HIV/TB patients were evaluated.

Methods: Fifteen patients with HIV/TB, ten with HIV, four with TB, and five controls were enrolled.

A high frequency of macrolide-lincosamide-streptogramin resistance determinants in Staphylococcus aureus isolated in South Korea.

Genes conferring resistance to one of the macrolide-lincosamide-streptogramin (MLS) antibiotics may confer cross-resistance to others, because they have similar effects on bacterial protein synthesis. In Korea, over 70% of Staphylococcus aureus isolates are methicillin-resistant and erythromycin-resistant methicillin-resistant S. aureus (MRSA) is also prevalent.

Inhibition of HIV-1 integrase by galloyl glucoses from Terminalia chebula and flavonol glycoside gallates from Euphorbia pekinensis.

The bioassay-directed isolation of Terminalia chebula fruits afforded four human immunodeficiency virus type 1 (HIV-1) integrase inhibitors, gallic acid ( 1) and three galloyl glucoses ( 2 - 4). In addition, four flavonol glycoside gallates ( 5 - 8) from Euphorbia pekinensis containing the galloyl moiety also showed the inhibitory activity at a level comparable to those of 2 - 4. By comparison with the activities of the compounds not bearing this moiety, it is proposed that the galloyl moiety plays a major role for inhibition against the 3'-processing of HIV-1 integrase of these compounds.