A Versatile Terahertz Chemical Microscope and Its Application for the Detection of Histamine

Terahertz waves have gained increasingly more attention because of their unique characteristics and great potential in a variety of fields. In this study, we introduced the recent progress of our versatile terahertz chemical microscope (TCM) in the detection of small biomolecules, ions, cancer cells, and antibody–antigen immunoassaying. We highlight the advantages of our TCM for chemical sensing and biosensing, such as label-free, high-sensitivity, rapid response, non-pretreatment, and minute amount sample consumption, compared with conventional methods. Furthermore, we demonstrated its new application in detection of allergic-related histamine at low concentration in buffer solutions.

Protein degradation analysis by affinity microfluidics

Protein degradation mediated by the ubiquitin-proteasome pathway regulates signaling events in all eukaryotic cells, with implications in pathological conditions such as cancer and neurodegenerative diseases. Detection of protein degradation is an elementary need in basic and translational research. In vitro degradation assays, in particular, have been instrumental in the understanding of how cell proliferation and other fundamental cellular processes are regulated. These assays are direct, quantitative and highly informative but also laborious, typically relying on low-throughput polyacrylamide gel-electrophoresis followed by autoradiography or immunoblotting. We present protein degradation on chip (pDOC), a MITOMI-based integrated microfluidic device for discovery and analysis of ubiquitin mediated proteolysis. The platform accommodates microchambers on which protein degradation is assayed quickly and simultaneously in physiologically relevant environments, using minute amount of reagents. Essentially, pDOC provides a multiplexed, sensitive and colorimetric alternative to the conventional degradation assays, with relevance to biomedical and translational research.

Identification of Bioactive Plant Volatiles for the Carob Moth by Means of GC-EAD and GC-Orbitrap MS

The aim of this study was to validate a workflow that allows structural identification of plant volatiles that induce a behavioral response in insects. Due to the complexity of plant volatile emissions and the low levels at which these bioactive components tend to occur, gas chromatography-electroantennography (GC-EAD) was applied as the prime differentiator technique, i.e., to indicate particular peaks of interest in the chromatogram. In a next step, the analysis was repeated under identical conditions using GC-Orbitrap mass spectrometry (MS). Combining electron impact (EI) ionization and chemical ionization (CI) with the superior spectral resolution and mass accuracy of the technique enabled straightforward identification of these unknowns, with high confidence in a minute amount of time. Moreover, because of the intrinsic sensitivity of the technique, components that occur at trace amounts but may induce disproportional large behavioral responses are evenly well-identified. We were able to positively identify β-caryophyllene as a bioactive compound in female carob moths. Behavioral attraction was negatively correlated with the amount of β-caryophyllene in host fruits. In an oviposition experiment on filter paper, β-caryophyllene was stimulated in the range of 40–100 ng, while concentrations above 200 ng inhibited oviposition.

Fetal Hemoglobin Levels as Indicator of Frequency and Duration of Blood Donation

Hemoglobin F is normal hemoglobin seen in minute amount in adults. Increase in its level in adults is an indication of erythropoietic stress, which in most cases is linked to hemoglobinopathy. This study was undertaken to assess if physiological erythropoietic stress as seen in commercial blood donation, can increase it and thus be used as an indicator of frequency and duration of blood donation. The study involved 152 subjects including 88 commercial blood donors and 64 controls. Hemoglobin F was expressed as percentage concentration of the total hemoglobin. Results showed that hemoglobin F significantly increased in commercial blood donors when compared with the controls. There was also strong positive correlation between hemoglobin F level and age of the donors which was not the case with the controls. The results indicate that hemoglobin F level can be used as an indicator of the frequency and duration of blood donation. Though blood donation has some health benefits, the disadvantages of frequent donation outweigh these benefits and should be discouraged.

Exogenous Menadione Sodium Bisulphite Increases Pigments, Osmoprotectants and Alters Metabolism to Attenuate Cadmium Toxicity on Growth and Yield in Summer Squash (Cucurbita pepo)

The menadione sodium bisulphite (MSB) is hydrophilic and has been suggested a defensive molecule against different biotic and abiotic stresses. Cadmium (Cd) is a highly mobile element and even its minute amount causes toxicity in different organisms including plants. This experiment was conducted to elucidate whether seed priming with MSB could induce Cd tolerance in summer squash. The seed were primed with 0, 10 and 20 mM MSB and sown in pots filled with clean and dried sand saturated with Hoagland’s nutrients solution supplemented with different Cd concentrations (0 and 0.1 mM). The Cd stress reduced growth and contents of chlorophyll (Chl), osmoprotectants (soluble sugars, free amino acids, soluble proteins) and yield while increased oxidants such as hydrogen peroxide (H2O2) and malondialdehyde (MDA) and secondary metabolites (total phenolics and flavonoids). The Cd stress increased root and shoot Fe (4−18%, respectively) and Ca2+ (24−93%, respectively) concentration while decreased root and shoot Mg2+ concentration (31−39%, respectively). The summer squash transported Cd to shoot and compartmentalized it in the cells to avoid Cd toxicity. However, the plants raised from seed primed with MSB had higher contents of photosynthetic pigments (17−23% total Chl), secondary metabolites and osmoprotectants when grown under Cd stress. Further, MSB-priming attenuated the toxicity of Cd on nutrients acquisition and increased growth and yield in the summer squash. The MSB-priming reduced Cd uptake (84%) and also altered Cd compartmentalization at sub-cellular level, and mediated its accumulation in the cell wall and soluble fraction (vacuole) rather than in the chloroplasts and cell membranes. Overall, MSB-priming (10 mM) was much more effective and increased growth and yield of summer squash under Cd stress. © 2021 Friends Science Publishers

Synthesis of SnO2/CuO/SnO2 Multi-layered Structure for Photoabsorption: Compositional and Some Interfacial Structural Studies

Many metal oxide heterostructures have been synthesized as mixed oxides or layered structures for photocatalytic, photodegradation of pollutants and light-harvesting applications. However, in the layered structures the effects of interfacial properties and composition have largely not been explored. Hence, the effects of interfacial mixing and diffusion of sandwiched thin CuO layer on optical absorption of as-deposited and heat-treated multi-layered structured SnO2/CuO/SnO2 films were studied. The RBS analysis of the as-deposited films showed the presence of a minute amount of Cu in the surface and bottom SnO2 layers of the structure. We attributed this to inhomogeneous layer thickness evidenced by very low Sn/Cu atoms ratio of the CuO layer. However, the thermal treatment of the layered structure led to pronounced interlayer mixing and consequent formation of SnO2-CuO solid solutions throughout the layered structure. The layer integrity of the inserted CuO of the as-deposited films was very high and the as-deposited structure was far more optically absorbing. However, the annealed structure showed lesser optical absorption because of the onset of interfacial mixing and improved crystallization. This reflected in the optical bandgap variations of the as-deposited and annealed multilayered structures. The significance of this result is that the multi-layered films possess band narrowing – evidence of increased photon absorption - making it a better candidate than pure SnO2 oxide for photocatalysis, photodegradation and photodetection applications. It also pointed to the fact that attention must be paid to effects of heat treatments or annealing when inserting an absorbing layer into a photocatalyst or a material meant for photodegradation or any light-harvesting material.

Transferability of a Convolutional Neural Network (CNN) to Measure Traffic Density

Whereas detecting individual vehicles in a video image using a convolutional neural network (CNN) prevails for traffic surveillance, CNNs also have been successfully adapted to counting vehicles via a regression method, which conveys the advantages of simplifying the model structure, and inference time can be reduced in the field. This model also demands much less human effort to tag images with labels. The number of vehicles in an image becomes the label, rather than bounding boxes drawn around every single vehicle. Nonetheless, the labeling task takes considerable time whenever a CNN model is trained and tested for a new road segment. There are two ways to alleviate the human effort involved in using this method. A previous study used a pseudo label pre-training method, and another study employed an image synthesis method to solve the problem. Besides these two methods, we investigated the model transferability to reduce the labeling effort. Using a CNN that was fully trained on images of a road segment, we devised a robust way to utilize the trained model for another site by transforming the model output with a simple quadratic equation. The utility of the proposed method was confirmed at the expense of a minute amount of deterioration in accuracy.

Ferroelectric and Dielectric Properties of BaZr0.2[Ti(1-x)Mgx/3Ta2x/3]0.8O3 Solid Solution

BaZr0.2[Ti(1-x)Mgx/3Ta2x/3]0.8O3 (x = 0.0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0) (BZTMT) ceramics were prepared through conventional solid state ceramic route. The crystal structure and microstructure of the compounds were investigated respectively using XRD and SEM. The dielectric properties were measured in the frequency range of 100 Hz–1 MHz. The ferroelectric Curie temperature of BaZr0.2Ti0.8O3 (x = 0) shifted from 21°C to -10°C with the addition of minute amount of dopant (x = 0.025) and the paraelectric transition temperature is diffusive in nature. The relative permittivity and dielectric loss of BZTMT at 1 MHz varies from 5205 to 24 and 1.8 × 10–2 to 2.0 × 10–5 respectively, as the value of x increases from 0 to 1.

Experimental observation of the elastic range scaling in turbulent flow with polymer additives

A minute amount of long-chain flexible polymer dissolved in a turbulent flow can drastically change flow properties, such as reducing the drag and enhancing mixing. One fundamental riddle is how these polymer additives interact with the eddies of different spatial scales existing in the turbulent flow and, in turn, alter the turbulence energy transfer. Here, we show how turbulent kinetic energy is transferred through different scales in the presence of the polymer additives. In particular, we observed experimentally the emerging of a previously unidentified scaling range, referred to as the elastic range, where increasing amount of energy is transferred by the elasticity of the polymers. In addition, the existence of the elastic range prescribes the scaling of high-order velocity statistics. Our findings have important implications to many turbulence systems, such as turbulence in plasmas or superfluids where interaction between turbulent eddies and other nonlinear physical mechanisms are often involved.

Tailoring the resolution of single-cell RNA sequencing for primary cytotoxic T cells

Single-cell RNA sequencing in principle offers unique opportunities to improve the efficacy of contemporary T-cell based immunotherapy against cancer. The use of high-quality single-cell data will aid our incomplete understanding of molecular programs determining the differentiation and functional heterogeneity of cytotoxic T lymphocytes (CTLs), allowing for optimal therapeutic design. So far, a major obstacle to high depth single-cell analysis of CTLs is the minute amount of RNA available, leading to low capturing efficacy. Here, to overcome this, we tailor a droplet-based approach for high-throughput analysis (tDrop-seq) and a plate-based method for high-performance in-depth CTL analysis (tSCRB-seq). The latter gives, on average, a 15-fold higher number of captured transcripts per gene compared to droplet-based technologies. The improved dynamic range of gene detection gives tSCRB-seq an edge in resolution sensitive downstream applications such as graded high confidence gene expression measurements and cluster characterization. We demonstrate the power of tSCRB-seq by revealing the subpopulation-specific expression of co-inhibitory and co-stimulatory receptor targets of key importance for immunotherapy.