An inversion method for calculating formation and borehole parameters in X-ray lithology density logging.

The use of X-ray sources in place of the 137Cs sources used in traditional lithology density logging methods has become a new trend in the development of nuclear logging techniques. How to eliminate the effects of drilling fluids or mudcake in the measurement process is a key question that determines the accuracy of measurement. In order to reduce the effects of mudcake and improve the accuracy of measurement of formation parameters, this paper presents an inversion method that can accurately calculate formation and borehole parameters and is suitable for X-ray lithology density logging. The general process of this inversion method is described below. First, a response model for broad-beam attenuation during X-ray lithology density logging is derived. Subsequently, the responses of four detectors under various formation and borehole conditions are studied by means of Monte Carlo simulation, and the energy spectra measured by each detector are divided into four energy windows (ranges) depending on the correlation with formation parameters. Finally, accurate values of formation and borehole parameters are obtained through iterative inversion using the Levenberg-Marquardt (LM) algorithm. The results of this study show that compared with previously established analysis methods, the inversion method based on forward modeling can effectively improve the accuracy of measurement of formation density and lithology index during X-ray lithology density logging, reduce the influence of the borehole environment, and overcome the deficiencies of data processing techniques based on the spine and ribs plot.

Bovine Serum Albumin Molecularly Imprinted Electrochemical Sensors Modified by Carboxylated Multi-Walled Carbon Nanotubes/CaAlg Hydrogels.

In this paper, sodium alginate (NaAlg) was used as functional monomers, bovine serum albumin (BSA) was used as template molecules, and calcium chloride (CaCl2) aqueous solution was used as a cross-linking agent to prepare BSA molecularly imprinted carboxylated multi-wall carbon nanotubes (CMWCNT)/CaAlg hydrogel films (MIPs) and non-imprinted hydrogel films (NIPs). The adsorption capacity of the MIP film for BSA was 27.23 mg/g and the imprinting efficiency was 2.73. The MIP and NIP hydrogel film were loaded on the surface of the printed electrode, and electrochemical performance tests were carried out by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) using the electrochemical workstation. The loaded MIP film and NIP film effectively improved the electrochemical signal of the bare carbon electrode. When the pH value of the Tris HCl elution solution was 7.4, the elution time was 15 min and the adsorption time was 15 min, and the peak currents of MIP-modified electrodes and NIP-modified electrodes reached their maximum values. There was a specific interaction between MIP-modified electrodes and BSA, exhibiting specific recognition for BSA. In addition, the MIP-modified electrodes had good anti-interference, reusability, stability, and reproducibility. The detection limit (LOD) was 5.6 × 10-6 mg mL-1.

Machine learning-assisted flexible wearable device for tyrosine detection.

Early diagnosis of pathological markers can significantly shorten the rate of viral transmission, reduce the probability of infection, and improve the cure rate of diseases. Therefore, analytical techniques for identifying pathological markers and environmental toxicants have received considerable attention from researchers worldwide. However, the most popular techniques used in clinical settings involve expensive precision instruments and complex detection processes. Thus, a simpler, more efficient, rapid, and intelligent means of analysis must be urgently developed. Electrochemical biosensors have the advantages of simple processing, low cost, low sample preparation requirements, rapid analysis, easy miniaturization, and integration. Thus, they have become popular in extensive research. Machine learning is widely used in material-assisted synthesis, sensor design, and other fields owing to its powerful data analysis and simulation learning capabilities. In this study, a machine learning-assisted carbon black-graphene oxide conjugate polymer (CB-GO/CP) electrode, in conjunction with a flexible wearable device, is proposed for the smart portable detection of tyrosine (Tyr). Input feature value data are obtained for the artificial neural network (ANN) and support vector machines (SVM) model learning via multiple data collections in artificial urine and by recording the pH and temperature values. The results reveal that a machine-learning model that integrates multiple external factors is more accurate for the prediction of Tyr concentration.

Echocardiographic parameters predicting spontaneous closure of ductus arteriosus in preterm infants.

Objective: To evaluate the value of echocardiographic parameters in predicting early spontaneous closure of ductus arteriosus in premature infants. Methods: 222 premature infants admitted to the neonatal ward of our hospital were selected, and patent ductus arteriosus was detected by echocardiography 48 h after birth. On the 7th day, whether the ductus arteriosus was closed naturally in this cohort was observed. The infants whose ductus arteriosus were not closed were identified as the PDA group (n = 109), and the other infants were included in the control group (n = 113). The echocardiographic parameters of the two groups of premature infants at 48 h after birth were single-factor statistically and Pearson correlation analyzed, and the parameters with statistically significant differences in single-factor analyzed were selected for multivariate logistic stepwise regression analysis. Results: The ductus arteriosus shunt velocity and the pressure difference between the descending aorta and the pulmonary artery (ΔPs) in the PDA group were lower than those in the control group (P < 0.05). The pulmonary artery pressure (PASP) in the PDA group was higher than that in the control group (P < 0.05). According to the multivariate logistic stepwise regression analysis, only the maximum shunt velocity of ductus arteriosus was correlated with early spontaneous closure of ductus arteriosus in 48 h first echocardiographic parameters (P = 0.049). The receiver operating characteristic (ROC) curve indicates the optimal critical point of echocardiographic ductus arteriosus shunt velocity in premature infants 48 h after birth was 1.165 m/s. Conclusion: Echocardiographic parameters are of great value in predicting the early spontaneous closure of ductus arteriosus in premature infants. In particular, the ductus arteriosus shunt velocity is correlated with the early spontaneous closure of ductus arteriosus.

A Time-Division Multiplexing Multi-Channel Micro-Electrochemical Workstation with Carbon-Based Material Electrodes for Online L-Trosine Detection.

In the background of the rapid development of artificial intelligence, big data, IoT, 5G/6G, and other technologies, electrochemical sensors pose higher requirements for high-throughput detection. In this study, we developed a workstation with up to 10 channels, which supports both parallel signal stimulation and online electrochemical analysis functions. The platform was wired to a highly integrated Bluetooth chip used for wireless data transmission and can be visualized on a smartphone. We used this electrochemical test platform with carbon-graphene oxide/screen-printed carbon electrodes (CB-GO/SPCE) for the online analysis of L-tyrosine (Tyr), and the electrochemical performance and stability of the electrodes were examined by differential pulse voltammetry (DPV). The CB-GO-based screen-printed array electrodes with a multichannel electrochemical platform for Tyr detection showed a low detection limit (20 µM), good interference immunity, and 10-day stability in the range of 20-200 µM. This convenient electrochemical analytical device enables high-throughput detection and has good economic benefits that can contribute to the improvement of the accuracy of electrochemical analysis and the popularization of electrochemical detection methods in a wide range of fields.

Electrochemical biosensor based on antibody-modified Au nanoparticles for rapid and sensitive analysis of influenza A virus.

To cope with the easy transmissibility of the avian influenza A virus subtype H1N1, a biosensor was developed for rapid and highly sensitive electrochemical immunoassay. Based on the principle of specific binding between antibody and virus molecules, the active molecule-antibody-adapter structure was formed on the surface of an Au NP substrate electrode; it included a highly specific surface area and good electrochemical activity for selective amplification detection of the H1N1 virus. The electrochemical test results showed that the BSA/H1N1 Ab/Glu/Cys/Au NPs/CP electrode was used for the electrochemical detection of the H1N1 virus with a sensitivity of 92.1 µA (pg/mL)-1 cm2, LOD of 0.25 pg/ml, linear ranges of 0.25-5 pg/mL, and linearity of (R 2 = 0.9846). A convenient H1N1 antibody-based electrochemical electrode for the molecular detection of the H1N1 virus will be of great use in the field of epidemic prevention and raw poultry protection. Supplementary Information: The online version contains supplementary material available at 10.1007/s11581-023-04944-w.

One-step synthesis of nanosilver embedding laser-induced graphene for H2O2 sensor.

During the novel coronavirus pandemic, hydrogen peroxide (H2O2) played an important role as a disinfectant. However, high concentrations of H2O2 can also cause damage to the skin and eyes. Therefore, the quantitative and qualitative detection of H2O2 is an important research direction. In this work, we report a one-step laser-induced synthesis of graphene doped with Ag NPs composites. It directly trims screen printed electrodes (SPE). Firstly, we did the timekeeping current method (CA) test on H2O2 using a conventional platinum sheet as the counter electrode, and obtained linear ranges of 1-110 µM and 110-800 µM with a sensitivity of 118.7 and 96.3 µAmM-1cm-2 and a low detection limit of (LOD) 0.24 µM and 0.31 µM. On this basis we have also achieved a good result in CA testing using Screen printed carbon electrodes (SPCE), laying the foundation for portable testing. The sensor has excellent interference immunity and high selectivity.

Water-soluble dinuclear iridium(III) and ruthenium(II) bis-terdentate complexes: photophysics and electrochemiluminescence.

The synthesis, photophysics, and electrochemiluminescence (ECL) of four water-soluble dinuclear Ir(III) and Ru(II) complexes (1-4) terminally-capped by 4'-phenyl-2,2':6',2''-terpyridine (tpy) or 1,3-di(pyrid-2-yl)-4,6-dimethylbenzene (N^C^N) ligands and linked by a 2,7-bis(2,2':6',2''-terpyridyl)fluorene with oligoether chains on C9 are reported. The impact of the tpy or N^C^N ligands and metal centers on the photophysical properties of 1-4 was assessed by spectroscopic methods including UV-vis absorption, emission, and transient absorption, and by time-dependent density functional theory (TDDFT) calculations. These complexes exhibited distinct singlet and triplet excited-state properties upon variation of the terminal-capping terdentate ligands and the metal centers. The ECL properties of complexes 1-3 with better water solubility were investigated in neutral phosphate buffer solutions (PBS) by adding tripropylamine (TPA) as a co-reactant, and the observed ECL intensity followed the descending order of 3 > 1 > 2. Complex 3 bearing the [Ru(tpy)2]2+ units displayed more pronounced ECL signals, giving its analogues great potential for further ECL study.

MC-GAT: multi-layer collaborative generative adversarial transformer for cholangiocarcinoma classification from hyperspectral pathological images.

Accurate histopathological analysis is the core step of early diagnosis of cholangiocarcinoma (CCA). Compared with color pathological images, hyperspectral pathological images have advantages for providing rich band information. Existing algorithms of HSI classification are dominated by convolutional neural network (CNN), which has the deficiency of distorting spectral sequence information of HSI data. Although vision transformer (ViT) alleviates this problem to a certain extent, the expressive power of transformer encoder will gradually decrease with increasing number of layers, which still degrades the classification performance. In addition, labeled HSI samples are limited in practical applications, which restricts the performance of methods. To address these issues, this paper proposed a multi-layer collaborative generative adversarial transformer termed MC-GAT for CCA classification from hyperspectral pathological images. MC-GAT consists of two pure transformer-based neural networks including a generator and a discriminator. The generator learns the implicit probability of real samples and transforms noise sequences into band sequences, which produces fake samples. These fake samples and corresponding real samples are mixed together as input to confuse the discriminator, which increases model generalization. In discriminator, a multi-layer collaborative transformer encoder is designed to integrate output features from different layers into collaborative features, which adaptively mines progressive relations from shallow to deep encoders and enhances the discriminating power of the discriminator. Experimental results on the Multidimensional Choledoch Datasets demonstrate that the proposed MC-GAT can achieve better classification results than many state-of-the-art methods. This confirms the potentiality of the proposed method in aiding pathologists in CCA histopathological analysis from hyperspectral imagery.

Research on advanced methods of electrochemiluminescence detection combined with optical imaging analysis for the detection of sulfonamides.

In this study, a novel method that combines electrochemiluminescence (ECL) analysis and digital image processing was developed for the detection of sulfonamides. This method is based on the ECL system of ruthenium terpyridine, with 1 mM tripropylamine as a co-reactant to enhance the performance. Under the optimal conditions comprising a solution of pH 7 and a scanning rate of 0.08 V s-1, the Pt electrode has an excellent linear detection range from 5 µM to 5 mM, with a detection limit of 0.85 µM (S/N = 3). A wireless camera is used to record the light-emitting process. The recordings are processed, and the digital images are extracted using image-processing algorithms implemented in Python to calculate the brightness value of the image, which has a linear relationship with the logarithm of the sulfonamide concentration. Image analysis simplifies and improves the stability of the ECL analysis process, while also increasing the speed of analysis. The results indicate that the method can successfully detect a sulfonamide concentration of 5 µM. Thus, the analysis method of ECL combined with image processing is feasible for the detection of sulfonamides, thereby displaying its potential applicability as a novel method in drug and food safety, for instance, for sulfonamide detection in antibiotics.

In situ detection of heavy metal ions in sewage with screen-printed electrode-based portable electrochemical sensors.

The rapid development of industrial technologies continuously increases the heavy metal pollution of water resources. Recently, portable electrochemical analysis-based devices for detecting heavy metal ions have attracted much attention due to their excellent performance and low fabrication costs. However, it has proven difficult to accommodate complex testing needs in a cost-effective manner. To address these limitations, we propose a new system for the in situ detection of heavy metals in wastewater using an organic light-emitting diode-based panel to display data in real time and Bluetooth to transmit data to a smartphone for rapid analysis. The fabricated device integrates an in situ signal analysis circuit, a Bluetooth chip, a photocured 3D-printed shell, and an electrode sleeve interface. In addition, a fully screen-printed functional electrode plate containing chitosan/PANi-Bi nanoparticle@graphene oxide multi-walled carbon nanotubes is utilized for the rapid detection of heavy metal ions. This device can perform wireless data transmission and analysis and in situ signal acquisition and processing. The sensor exhibits a high sensitivity (Hg2+: 88.34 µA ppm-1 cm-2; Cu2+: 0.956 µA ppm-1 cm-2), low limit of detection (Hg2+: 10 ppb, Cu2+: 0.998 ppm) and high selectivity during the detection of copper and mercury ions in tap water under non-laboratory conditions, and the results of real-time tests reveal that parameters measured in the field and laboratory environments are identical. Hence, this small, portable, electrochemical sensor with a screen-printed electrode can be effectively used for the real-time detection of copper and mercury ions in complex water environments.

Electrochemiluminescence Detection of Sunset Yellow by Graphene Quantum Dots.

Use of food additives, such as colorants and preservatives, is highly regulated because of their potential health risks to humans. Therefore, it is important to detect these compounds effectively to ensure conformance with industrial standards and to mitigate risk. In this paper, we describe the preparation and performance of an ultrasensitive electrochemiluminescence (ECL) sensor for detecting a key food additive, sunset yellow. The sensor uses graphene quantum dots (GQDs) as the luminescent agent and potassium persulfate as the co-reactant. Strong and sensitive ECL signals are generated in response to trace amounts of added sunset yellow. A detection limit (signal-to-noise ratio = 3) of 7.6 nM and a wide linear range from 2.5 nM to 25 µM are demonstrated. A further advantage of the method is that the luminescent reagents can be recycled, indicating that the method is sustainable, in addition to being simple and highly sensitive.

Intelligent Detection Platform for Simultaneous Detection of Multiple MiRNAs Based on Smartphone.

As a marker of malignant tumors, miRNA is closely related to the occurrence and metastasis of tumors. How to achieve rapid and sensitive real-time detection is important for clinical prevention and treatment of cancer. In this study, an intelligent detection platform based on smartphone image processing technology made point-of-care testing a reality. This new smart approach could detect multiple targets simultaneously and sensitively. Hydrogel microparticles of different coding modes (shapes, numbers) were prepared by flow lithography to detect different miRNAs. After sandwich immunoassays, different shapes of hydrogels showed different fluorescence intensities depending on their targets. Images were captured by a smartphone and then analyzed by image recognition processing software installed on the smartphone. The concentration of miRNA was obtained within 10 s. The entire reaction process did not exceed 2 h. This intelligent and portable detection platform for miRNAs was reliable and the limit of detection reached the femtomole level. This work provided a demonstration of intelligent, portable, real-time detection of tumor markers.

Adsorption and Electrochemical Detection of Bovine Serum Albumin Imprinted Calcium Alginate Hydrogel Membrane.

In this paper, bovine serum albumin (BSA)-imprinted calcium alginate (CaAlg) hydrogel membrane was prepared using BSA as a template, sodium alginate (NaAlg) as a functional monomer, and CaCl2 as a cross-linker. The thickness of the CaAlg membrane was controlled by a glass rod enlaced with brass wires (the diameter was 0.1, 0.2, 0.3, 0.4, and 0.5 mm). The swelling properties of the CaAlg membranes prepared with different contents of NaAlg were researched. Circular dichroism indicated that the conformation of BSA did not change during the preparing and eluting process. The thinner the CaAlg hydrogel membrane was, the larger the adsorption capacity and the higher the imprinting efficiency of the CaAlg. The maximum adsorption capacity of molecularly imprinted polymer (MIP) and non-imprinted CaAlg hydrogel membrane (NIP) was 38.6 mg·g-1 and 9.2 mg·g-1, respectively, with an imprinting efficiency of 4.2. The MIP was loaded on the electrode to monitor the selective adsorption of BSA by voltammetry curve.

Shape Coding Microhydrogel for a Real-Time Mycotoxin Detection System Based on Smartphones.

How to create a portable and quick way to detect multiple coexisting toxins is closely related to everyone's health. In this paper, we have established a real-time mycotoxin detection system that combined shape-encoded hydrogel particle preparation technology and image processing technology with smartphone portable devices. First, hydrogel microparticles containing a specific recognition toxin aptamer were programmable synthesized by stop-flow lithography. The hydrogel particles prepared by us had clear, variable signals and high coding capacity. Then, the indirect competitive detection based on aptamers was simple and rapid; the total reaction time was no more than 1 h 45 min and the image processing process was no more than 10 s. Finally, images could be captured by cameras on portable devices and smartphones. The self-built Android app that used the image recognition program installed on the smartphone would analyze the image and return the results in real time. The results showed that the detection limit reached 0.1 ng/mL, which was lower than the standard. In summary, this platform provides a fast, portable, high-throughput detection solution for real-time detection of mycotoxins, with excellent application prospects.

Low-Operating-Voltage Resistive Memory Based on Bi1+δFe0.95Zn0.05)O3 Films.

A resistive memory device based on the Ag/Bi1+δ(Fe0.95Zn0.05)O3/SRO/Pt/TiO2/SiO2/Si(100) structure was prepared using radio frequency magnetron sputtering. The composition of the thin film element was analyzed by X-ray photoelectron spectroscopy and the thickness of the thin film was characterized by scanning electron microscope. Through the electrical test, we found that the device exhibited low operating voltage, which included VSET of about 0.1 V, VRESET of about -0.1 V, and VF of about 0.25 V. This facilitated the perfect integration of the device with the circuit design. Testing for 10,000 s at a substrate temperature of 85 °C, the device showed excellent retention. The I-V fitting curves of the resistive devices were analyzed. The low resistance state was in line with the ohmic mechanism and the high resistance state was in accordance with the Space Charge Limited Current mechanism. The resistance change of the device was attributed to the formation of Ag conductive filaments.

Highly Flexible Resistive Switching Memory Based on the Electronic Switching Mechanism in the Al/TiO2/Al/Polyimide Structure.

A highly flexible resistive switching (RS) memory was fabricated in the Al/TiO2/Al/polyimide structure using a simple and cost-effective method. An electronic-resistive-switching-based flexible memory with high performance that can withstand a bending strain of up to 3.6% was obtained. The RS properties showed no obvious degradation even after the bending tests that were conducted up to 10 000 times, and over 4000 writing/erasing cycles were confirmed at the maximally bent state. The superior electrical properties against the mechanical stress of the device can be ascribed to the electronic RS mechanism related to electron trapping/detrapping, which can prevent the inevitable degradation in the case of the RS related with the ionic defects.

Facile Synthesis of MoS2/Reduced Graphene Oxide@Polyaniline for High-Performance Supercapacitors.

The molybdenum disulfide/reduced graphene oxide@polyaniline (MoS2/RGO@PANI) was facilely and effectively prepared through a two-stage synthetic method including hydrothermal and polymerized reactions. The rational combination of two components allowed polyaniline (PANI) to uniformly cover the outer face of molybdenum disulfide/reduced graphene oxide (MoS2/RGO). The interaction between the two initial electrode materials produced a synergistic effect and resulted in outstanding energy storage performance in terms of greatest capacitive property (1224 F g(-1) at 1 A g(-1)), good rate (721 F g(-1) at 20 A g(-1)), and cyclic performance (82.5% remaining content after 3000 loops). The symmetric cell with MoS2/RGO@PANI had a good capacitive property (160 F g(-1) at 1 A g(-1)) and energy and power density (22.3 W h kg (-1) and 5.08 kW kg(-1)).

Synthesis of Large-Area Highly Crystalline Monolayer Molybdenum Disulfide with Tunable Grain Size in a H2 Atmosphere.

Large-area and highly crystalline monolayer molybdenum disulfide (MoS2) with a tunable grain size was synthesized in a H2 atmosphere. The influence of introduced H2 on MoS2 growth and grain size, as well as the corresponding mechanism, was tentatively explored by controlling the H2 flow rate. The as-grown monolayer MoS2 displays excellent uniformity and high crystallinity evidenced by Raman and high-resolution transmission electron microscopy. The Raman results also give an indication that the quality of the monolayer MoS2 synthesized in a H2 atmosphere is comparable to that synthesized by using seed or mechanical exfoliation. In addition, the electronic properties and dielectric inhomogeneity of MoS2 monolayers were also detected in situ via scanning microwave microscopy, with measurements on impedance and differential capacitance (dC/dV). Back-gated field-effect transistors based on highly crystalline monolayer MoS2 shows a field-effect mobility of ∼13.07 cm2 V(-1) s(-1) and an Ion/Ioff ratio of ∼1.1×10(7), indicating that the synthesis of large-area and high-quality monolayer MoS2 with H2 is a viable method for electronic and optoelectronic applications.

Prenatal ultrasound screening for external ear abnormality in the fetuses.

OBJECTIVES: To investigate the best time of examination and section chosen of routine prenatal ultrasound screening for external ear abnormalities and evaluate the feasibility of examining the fetal external ear with ultrasonography. METHODS: From July 2010 until August 2011, 42118 pregnant women with single fetus during 16-40 weeks of pregnancy were enrolled in the study. Fetal auricles and external auditory canal in the second trimester of pregnancy were evaluated by routine color Doppler ultrasound screening and systematic screening. Ultrasound images of fetal external ears were obtained on transverse-incline view at cervical vertebra level and mandible level and on parasagittal view and coronal view at external ear level. RESULTS: Five fetuses had anomalous ears including bilateral malformed auricles with malformed external auditory canal, unilateral deformed external ear, and unilateral microtia. The detection rate of both auricles was negatively correlated with gestational age. Of the 5843 fetuses undergoing a routine ultrasound screening, 5797 (99.21%) had bilateral auricles. Of the 4955 fetuses following systematic screening, all fetuses (100%) had bilateral auricles. The best time for fetal auricles observation with ultrasonography is 20-24 weeks of pregnancy. CONCLUSIONS: Detection of external ear abnormalities may assist in the diagnosis of chromosomal abnormalities.