The Recognition of Sweat Latent Fingerprints with Green-Emitting Carbon Dots

The recognition of fingerprints has played an extremely important role in criminal investigations, due to its uniqueness. This paper reports on the recognition of sweat latent fingerprints using green-emitting, environment-friendly carbon dots prepared with DL-malic acid and ethylenediamine, and the exploration of impacting factors in the development process of fingerprints. The experiments showed that better fingerprint images could be obtained when the latent fingerprints are developed in green-emitting carbon dots with pH 9 for 30 min, at room temperature. The reported method was also effective for latent fingerprints on a variety of substrates, as well as for those water-immersed ones, where the developed fingerprint remained stable after long-term preservation. Furthermore, the fluorescent three-dimensional fingerprint image could provide direct and simple evidence on pressing habits. The objective of this paper was to present this method. The method may help to narrow the range of suspects during criminal investigations and in forensic science

LncRNA DANCR reduces anoxia-induced rat myocardial cell line H9c2 injury by targeting miR-3646

Objective To study the role of long non-coding RNA (lncRNA) differentiation antagonizing non-coding RNA (DANCR) in myocardial ischemia and the targeted regulation of microRNA-3646 (miR-3646). Methods H9c2 cells(rat cardiomyocytes cell line)were separated into 6 groups: control group, anoxia group, pc-DANCR (DANCR over-expression) group, pc-NC (DANCR over-expression control) group, miR-3646 mimic (miR-3646 mimicry) group, mimic NC (miR-3646 mimic control) group, and pc-DANCR+miR-3646 mimic group; RT-qPCR method was implemented to measure the expression of lncRNA DANCR and miR-3646 to determine the transfection effect; Flow cytometry was performed to measure the rate of apoptosis; CCK-8 assay was implemented to cell measure survival; Electron microscopy was applied to observe the structural injury of H9c2 cells; Western blot was performed to measure the expression of activated cleaved caspase-3 (cleaved caspase-3) and heme oxygenase-1 (Ho-1). Dual-luciferase experiments were performed to verify the targeting relationship of miR-3646 with lncRNA DANCR and Ho-1. RNA interference Ho-1 (ShHo-1) and pc-DANCR were co-transfected into H9c2 cells, and the cell viability was measured. Results Compared with the control group, the injury and apoptosis of H9c2 cells in the anoxia group were serious, the survival rate and the expression of lncRNA DANCR were decreased, and the expression of miR-3646 was increased (PPPPConclusions LncRNA DANCR can down-regulate the expression of miR-3646 and promote the expression of Ho-1 to alleviate anoxia-induced H9c2 cells injury and improve cell survival

Reservoir Permeability Calculation under Flow Unit Control

The No. 2 gas field in the X depression is a low-permeability tight reservoir with a complex lithology, pore structure, and strong physical heterogeneity, and the conventional core porosity–permeability regression method does not meet the requirements of fine evaluation in terms of the accuracy of permeability calculation. The flow unit method has great advantages in improving the accuracy of permeability calculation, but the FZI calculation method is too ideal and weakens the influence of the pore structure’s heterogeneity, and it needs to be verified that the FZI in the study area has a good correlation with the pore structure before it can be used. Therefore, based on analyzing the permeability control factors of low-permeability tight reservoirs, we analyze the correlation between three pore structure characterization parameters and the flow unit index FZI, which proves that the flow unit index FZI in this area can characterize the permeability difference within different flow units. Based on FZI theory and the cumulative frequency division method, we establish a fine evaluation model of four types of reservoirs in the study area. Through the response characteristics and correlation analysis of the conventional logging curves, we select three combined curves, establish a multi-parameter equation, and apply it to the permeability evaluation of the cored section that is not involved in modeling. The application results show that the calculated permeability is in good agreement with the core analysis results, which provides a theoretical basis for the fine evaluation of low-permeability tight reservoirs

The One-Step Preparation of Green-Emissioned Carbon Dots through Hydrothermal Route and Its Application

This paper reports the preparation of green-emissioned CDs by a one-step hydrothermal route with DL-malic acid and ethylenediamine as raw materials and further explored the impacts of the amount of reactants, the reaction time, and temperature upon the optical properties of prepared CDs, to select the optimal preparation parameters. The optical properties, surface groups, and element components of the prepared CDs have been systematically studied by UV-Vis absorption spectra, fluorescence spectra, FTIR, EDS, and XPS. The prepared CDs have been applied to realize the fingerprint development, fluorescence ink, and, specifically, the detection of Fe2+ through an inner filter effect with its detection range at 2.0×10−7−2.3×10−5 mol/L

Reservoir Permeability Calculation under Flow Unit Control

The No. 2 gas field in the X depression is a low-permeability tight reservoir with a complex lithology, pore structure, and strong physical heterogeneity, and the conventional core porosity–permeability regression method does not meet the requirements of fine evaluation in terms of the accuracy of permeability calculation. The flow unit method has great advantages in improving the accuracy of permeability calculation, but the FZI calculation method is too ideal and weakens the influence of the pore structure’s heterogeneity, and it needs to be verified that the FZI in the study area has a good correlation with the pore structure before it can be used. Therefore, based on analyzing the permeability control factors of low-permeability tight reservoirs, we analyze the correlation between three pore structure characterization parameters and the flow unit index FZI, which proves that the flow unit index FZI in this area can characterize the permeability difference within different flow units. Based on FZI theory and the cumulative frequency division method, we establish a fine evaluation model of four types of reservoirs in the study area. Through the response characteristics and correlation analysis of the conventional logging curves, we select three combined curves, establish a multi-parameter equation, and apply it to the permeability evaluation of the cored section that is not involved in modeling. The application results show that the calculated permeability is in good agreement with the core analysis results, which provides a theoretical basis for the fine evaluation of low-permeability tight reservoirs

One-Step Hydrothermal Synthesis of Yellow and Green Emitting Silicon Quantum Dots with Synergistic Effect

The concept of synergistic effects has been widely applied in many scientific fields such as in biomedical science and material chemistry, and has further attracted interest in the fields of both synthesis and application of nanomaterials. In this paper, we report the synthesis of long-wavelength emitting silicon quantum dots based on a one-step hydrothermal route with catechol (CC) and sodium citrate (Na-citrate) as a reducing agent pair, and N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAMO) as silicon source. By controlling the reaction time, yellow-emitting silicon quantum dots and green-emitting silicon quantum dots were synthesized with quantum yields (QYs) of 29.4% and 38.3% respectively. The as-prepared silicon quantum dots were characterized by fluorescence (PL) spectrum, UV–visible spectrum, high resolution transmission electron microscope (HRTEM), Fourier transform infrared (FT-IR) spectrometry energy dispersive spectroscopy (EDS), and Zeta potential. With the aid of these methods, this paper further discussed how the optical performance and surface characteristics of the prepared quantum dots (QDs) influence the fluorescence mechanism. Meanwhile, the cell toxicity of the silicon quantum dots was tested by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium (MTT) bromide method, and its potential as a fluorescence ink explored. The silicon quantum dots exhibit a red-shift phenomenon in their fluorescence peak due to the participation of the carbonyl group during the synthesis. The high-efficiency and stable photoluminescence of the long-wavelength emitting silicon quantum dots prepared through a synergistic effect is of great value in their future application as novel optical materials in bioimaging, LED, and materials detection

Industrialization of a FeSiBNbCu nanocrystalline alloy with high B-s of 1.39T and outstanding soft magnetic properties

High Fe content Fe76Si13B8Nb2Cu1 alloy ribbons with excellent quality and width of 20-55mm were successfully produced with industrial processes and raw materials, showing the superb manufacturability and impurity tolerance. It is found that impurities and ribbon width have a negligible influence on crystallization behavior, by comparing with samples prepared with high purity materials. The wide annealing time window can be over 50min in the optimal temperature range of 500-600 degrees C. Besides, industrialized Fe76Si13B8Nb2Cu1 alloy ribbons exhibit outstanding magnetic properties, including high saturation magnetic flux density (B-s) of 1.39T, high effect permeability of 28.8x10(3) at 1kHz and low coercivity of 3.5A/m, which are equivalent to ribbon prepared with pure materials. Extreme low core losses of 0.91W/kg at 1T and 1kHz, 5.30W/kg at 0.5T and 10kHz were also obtained in ring samples. It is found that fine nanostructure and wide stripe domains are the origins of excellent magnetic properties. This alloy with excellent performance has great potential in applications of high working B and frequency devices and will also be a new reference for industrialization of nanocrystalline alloy

Industrialization of a FeSiBNbCu nanocrystalline alloy with high B-s of 1.39T and outstanding soft magnetic properties

High Fe content Fe76Si13B8Nb2Cu1 alloy ribbons with excellent quality and width of 20-55mm were successfully produced with industrial processes and raw materials, showing the superb manufacturability and impurity tolerance. It is found that impurities and ribbon width have a negligible influence on crystallization behavior, by comparing with samples prepared with high purity materials. The wide annealing time window can be over 50min in the optimal temperature range of 500-600 degrees C. Besides, industrialized Fe76Si13B8Nb2Cu1 alloy ribbons exhibit outstanding magnetic properties, including high saturation magnetic flux density (B-s) of 1.39T, high effect permeability of 28.8x10(3) at 1kHz and low coercivity of 3.5A/m, which are equivalent to ribbon prepared with pure materials. Extreme low core losses of 0.91W/kg at 1T and 1kHz, 5.30W/kg at 0.5T and 10kHz were also obtained in ring samples. It is found that fine nanostructure and wide stripe domains are the origins of excellent magnetic properties. This alloy with excellent performance has great potential in applications of high working B and frequency devices and will also be a new reference for industrialization of nanocrystalline alloy