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The binder jetting (BJ) forming process is an additive manufacturing method based on discrete stacking and microdrop jetting technology. It has the advantages of low cost and high degree of automation; further, it has no special requirements pertaining to the shapes or structures of machining parts. However, at the present stage, all BJ processes involve hot curing, which leads to high molding and maintenance costs. To solve this problem, polyvinyl alcohol powder was used as the main material of the binder formed via the BJ process. The wetting of the powder bed by ink droplets was simulated, and the ink formula and printing process parameters were optimized. The final metal part was formed via defatting and sintering, resulting in a tensile strength of 323 MPa and density of 85.6%.

Balancing the benefits and risks of antimicrobials in health care requires an understanding of their effects on antimicrobial resistance at the population scale. Therefore, we aimed to investigate the association between the population antibiotics use and resistance rates and further identify their critical thresholds.Data for monthly consumption of six antibiotics (daily defined doses [DDDs]/1000 inpatient-days) and the number of cases caused by five common drug-resistant bacteria (occupied bed days [OBDs]/10,000 inpatient-days) from inpatients during 2009-2020 were retrieved from the electronic prescription system at Nanjing Drum Tower Hospital, a tertiary hospital in Jiangsu Province, China. Then, a nonlinear time series analysis method, named generalized additive models (GAM), was applied to analyze the pairwise relationships and thresholds of these antibiotic consumption and resistance.The incidence densities of carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Klebsiella pneumoniae (CRKP), and aminoglycoside-resistant Pseudomonas aeruginosa were all strongly synchronized with recent hospital use of carbapenems and glycopeptides. Besides, the prevalence of carbapenem-resistant Escherichia coli was also highly connected the consumption of carbapenems and fluoroquinolones. To lessen resistance, we determined a threshold for carbapenem and glycopeptide usage, where the maximum consumption should not exceed 31.042 and 25.152 DDDs per 1000 OBDs, respectively; however, the thresholds of fluoroquinolones, third-generation cephalosporin, aminoglycosides, and β-lactams have not been identified.The inappropriate usage of carbapenems and glycopeptides was proved to drive the incidence of common drug-resistant bacteria in hospitals. Nonlinear time series analysis provided an efficient and simple way to determine the thresholds of these antibiotics, which could provide population-specific quantitative targets for antibiotic stewardship.

Exosomes are potential biomarkers, which play an important role in early diagnosis and prognosis prediction of cancer-related diseases. Nevertheless, direct quantification of exosomes in biological fluid, especially in point-of-care tests (POCTs), remains extremely challenging. Herein, we developed a sensitive and portable electrochemical biosensor in combination with smartphones for quantitative analysis of exosomes. The improved double-antibody sandwich method-based poly-enzyme signal amplification was adopted to detect exosomes. We could detect as low as 7.23 ng of CD63-positive exosomes in 5 μL of serum within 2 h. Importantly, we demonstrated that the biosensor worked well with microliter-level serum and cell culture supernatant. The biosensor holds great potential for the detection of CD-63-expressing exosomes in early diagnosis of prostate disease because CD63-positive exosomes were less detected from the prostate patient serum. Also, the biosensor was used to monitor the secretion of exosomes with the drug therapy, showing a close relationship between the secretion of exosomes and the concentration of cisplatin. The biosensing platform provides a novel way toward POCT for the diagnosis and prognosis prediction of prostate disease and other diseases via biomarker expression levels of exosomes.

The developed biosensor detection system can complete the detection of air samples by collecting exhaled breath condensate, greatly reducing the time to diagnose tuberculosis.

The immunosensor can complete the sputum detection directly within a few minutes, which greatly shortens the diagnosis time of TB.

Nowadays, superhydrophobicity has been the limelight of the academic community owing to the plethora of applications. In this work, the downhill motion of liquid drops and liquid marbles was investigated by two distinct particle-laden interfaces. Liquid drops and liquid marbles accelerate firstly and then move on the slope with a steady velocity which decreases with the liquid viscosity. The steady velocity of liquid marbles is lower than that of liquid drops while the maximum aspect ratio of liquid marbles is higher than that of liquid drops, due to different interface interactions. The particles on the solid substrate enhance the motion of liquid drops while those on the liquid surface reduce the surface tension of liquid marbles. Both liquid drops on non-stick solid surface and non-stick liquid marbles on solid substrate could provide theoretical basis for the precisely targeted transportation of small quantities of liquids by particle-laden interfaces, especially in chemical and biomedical applications.

Tuberculosis (TB) mostly spreads from person to person through Mycobacterium tuberculosis (MTB). However, the majority of conventional detection methods for MTB cannot satisfy the requirements for actual TB detection. As one of the most promising powerful platforms, a silicon nanowire field-effect transistor (SiNW-FET) biosensor shows good prospect in TB detection. In this study, an enhanced SiNW-FET biosensor was developed for the rapid and sensitive detection of MTB. The surface functional parameters of the biosensor were explored and optimized. The SiNW-FET biosensor has good sensitivity with a detection limit of 0.01 fg/mL toward protein. The current change value shows a linear upward trend with the increase in protein concentration in the range of 1 fg/mL to 100 μg/mL. One whole test cycle can be accomplished within only 30 s. More importantly, a good distinction was realized in the sputum without pretreatment between normal people and TB patients, which greatly shortened the TB detection time (only 2-5 min, considering the dilution of sputum). Compared with other methods, the SiNW-FET biosensor can detect MTB with a remarkably broad dynamic linear range in a shorter time.

The growing demand for rare earth elements (REEs) necessitates cheap and environmentally friendly technologies for REEs recovery. Herein, we fabricated a pyrrolic-N doped activated carbon electrode (PPyN-AC) via two facile steps of in-situ polymerization of pyrrole monomers and further carbonization. Capacitive deionization (CDI) using PPyN-AC as electrodes is the first time applied for REEs capture from aqueous solution. PPyN-AC possesses a high N doping rate (9.55 at.%) and excellent capacitance (128.98 F/g). The CDI flow-by tests shows that the electrosorption capacity of La(III) by PPyN-AC electrode was 23.66 mg/g within 25 min at optimal conditions. The rapid and efficient La(III) electrosorption performance is attributed to the pyrrole-N configuration in the carbon matrix. Beyond that, the PPyN-AC electrode could selectively capture La(III) from a quaternary-component system of La(III), Fe(III), Ca(II) and Na(I) in aqueous solution. The REE selectivity mechanism, which involves the ionic charge, hydrated radii of metal ions, and hard-soft Lewis acid-base principle, was proposed. Overall, this work demonstrates a new efficient approach for the selective recovery of REEs from aqueous solution with minimal land and energy demands.

The addition of Ti and its compounds particles has the potential to effectively enhance the fracture toughness of B4C ceramics. However, the influence of different Ti-based compounds on B4C ceramics has not been extensively studied. In this work, B4C–TiB2 multiphase ceramics were prepared by adding 5% Ti or its compounds (TiO2, TiB2 or TiC) in B4C and the effects of the additives on the B4C ceramics were studied. For this purpose, we adopted a sintering process carried out in situ in the absence of pressure at a temperature of 2250 °C for 1 h. It was evident from the results that the additives are capable of enhancing the sintering densification characteristics and the properties exhibited by B4C, as opposed to single-phase B4C ceramics. Additionally, different additives have varied effects on the microstructures and mechanical properties of B4C–TiB2 multiphase ceramics. The results of the study indicate that the TiC-added sample exhibits the most optimal mechanical properties, with 4.52 MPa m1/2 fracture toughness, 344.0 MPa flexural strength, 26.2 GPa hardness, and 516.0 GPa elastic modulus.

Silicon nanowire devices employed traditional MEMS technology has the advantages of low cost and easy to batch fabricated, which can be applied for high‐sensitivity biological and chemical species detection. In the preparation process, the device performance would be greatly influenced by the BOE corrosion process of silicon oxide outside silicon nanowires, which will define the performance of devices in subsequent test. In this paper, pH solution test was used to characterize the response sensitivity of silicon nanowires in different etching times, with the help of SEM and I–V characteristics before and after corrosion, it can be found that the thickness of silicon oxide layer enclosed nanowires was gradually reduced until completely etched in about five minutes to expose the silicon nanowires, which revealed that the silicon nanowires could start to sense and respond to external stimulus only when the silicon oxide was very thin even disappeared. The effect of corrosion could be equivalent to the influence of silicon oxide thickness on device performance. It provides an effective way to control the fabrication process of high performance devices.

In this study, boron carbide-metallic boride (B4C-MeBx, Me = Ti, Zr, Nb, Ta, or W) multiphase ceramics were fabricated via in situ pressureless sintering at 2250 °C for 1 h. The effects of transition metal carbides, namely, TiC, ZrC, NbC, TaC, and WC, on the phase composition, microstructure, and mechanical properties of the ceramics were investigated. The results showed that MeC could facilitate the sintering densification of B4C by distributing second-phase particles uniformly throughout the B4C. Additionally, the main phases observed were B4C and (Me, W)Bx (Me = Ti, Zr, Nb, or Ta) due to the doping of a small amount of WC during the ball milling process. As a result, the mechanical properties of B4C-MeBx showed significant improvements when compared with those of single-phase B4C ceramics. B4C–NbB2 ceramics were found to exhibit the best mechanical properties, with an elastic modulus of 393.0 GPa, a hardness of 28.7 GPa, a flexural strength of 368.0 MPa, and a fracture toughness of 6.94 MPa m1/2.

Rapid and comprehensive diagnostic methods are necessary for early identification and monitoring of SARS-CoV-2. Here, we have developed a universal and portable three-in-one biosensor linked to a smartphone for co-detection of SARS-CoV-2 viral RNA, antigen, and antibody. In combination with a smartphone, the online monitoring of SARS-CoV-2 virus-infected patients from infection to immunization could be intelligently achieved.

Traditional detection methods have shortcomings such as time-consumption and requirement of large instruments, which cannot meet the demands for on-site detection or analysis. Silicon nanowire-field-effect transistor (SiNW-FET) biosensors have the advantages of high speed, high sensitivity, strong specificity, and ease of integration. However, SiNW-FET biosensors also have some demerits: they are too sensitive, environmental factors such as light, temperature, and pH easily cause interference, and their performance uniformity needs to be calibrated in advance. In this work, we constructed a self-contained and integrated microfluidic nano-detection system containing a SiNW-FET biosensor for bio-detection and analysis. All analysis processes including liquid sample delivery, optical modulation, constant temperature control, signal amplification and data acquisition, and result display were automatically performed. In series tests including light-guided ones by analyzing various types of samples with an automatic sample injection mode, the system shows good stability and robustness. Its signal accuracy was verified using a commercial high-precision ammeter (

In this paper, we propose a new strategy for the sensitive and specific detections of dimethyl methylphosphonate (DMMP), as a simulant of nerve agent Sarin. Our silicon nanowire based sensor is modified with carboxyphenylboronic acid (CPBA) to demonstrate great efficiency. The response time is less than 100 seconds to recognize the DMMP, which is a key ability for on-site monitoring. The sensor exhibits a good reversibility during the repeated measurements between DMMP vapor and air. The sensor still performs well after being exposed in high concentration of DMMP vapor with excellent recovery for 3 times. The sensor is demonstrated to have a linear behavior in detecting DMMP within the concentration of 13~65 ppm in gaseous phase with the limit of detection (LOD) of 100 ppb. It is expected that the proposed sensor enables the testing system accurate, rapid, sensitive and reversible for on-site detection of nerve agents in the future.

Since the preparation of TNT is always proceeded in acid solution, it is very difficult to accurately detect it at the production stage. Developing a TNT sensor which can work in sulfuric acid solution will be very helpful. This paper presents a TNT sensor based on SiNWs-FET which can quickly detect TNT in sulfuric acid. The detection mechanism is based on the fact that TNT molecules can selectively bond to the amino group of nanowires, which act as grid elements and modulate the conductance of the silicon nanowires, leading to the variation of SiNWs-FET drain-source current. The SiNWs-FET devices were fabricated on a (111) silicon-on-insulator wafer using controllable silicon anisotropy etching and self-limiting oxidation. The silicon nanowires were treated with oxygen plasma and 3-aminopropyltriethoxysilane (APTES) to form hydroxyl and amino groups on the surface of the nanowires, respectively. The SiNWs-FET sensor demonstrated highly sensitive detection to TNT molecule in aqueous solution with 0.1% dimethyl sulfoxide (DMSO) and sulfuric acid solutions. These experimental results show that the SiNWs-FET sensor can work stably and reliably in some harsh environment, even in high concentration of sulfuric acid. The rapid response time also reflected the advantages of SiNWs-FET sensors in TNT fast detection. In addition, the SiNWs-FET sensor showed selectivity to TNT, due to the specific bind between amino groups and nitro groups.

Tuberculosis (TB) mostly spreads from person to person through

Scenes play a crucial role in breaking the storyline of movies and TV episodes into semantically cohesive parts. However, given their complex temporal structure, finding scene boundaries can be a challenging task requiring large amounts of labeled training data. To address this challenge, we present a self-supervised shot contrastive learning approach (ShotCoL) to learn a shot representation that maximizes the similarity between nearby shots compared to randomly selected shots. We show how to apply our learned shot representation for the task of scene boundary detection to offer state-of-the-art performance on the MovieNet dataset while requiring only ~25% of the training labels, using 9x fewer model parameters and offering 7x faster runtime. To assess the effectiveness of ShotCoL on novel applications of scene boundary detection, we take on the problem of finding timestamps in movies and TV episodes where video-ads can be inserted while offering a minimally disruptive viewing experience. To this end, we collected a new dataset called AdCuepoints with 3,975 movies and TV episodes, 2.2 million shots and 19,119 minimally disruptive ad cue-point labels. We present a thorough empirical analysis on this dataset demonstrating the effectiveness of ShotCoL for ad cue-points detection., Accepted to CVPR 2021

Silicon nanowires (SiNWs) field effect transistor (FET) sensor has been considered to be one of the most promising candidates in the low cost detection of biological and chemical molecules. However, because of silicon nanowires' size distribution, the responses to the same sample of different SiNWs FET sensors show obvious fluctuation. Such problem brings great obstacles to used SiNWs FET sensors in high-precision detection. Here, we proposed a new strategy to calibrate SiNWs FET sensors by using its photoresponse. The foundation of this method is the similar relationship between SiNWs FET sensor response to the target and its own response to the illumination. The validity of this method were confirmed through the results of experiments that calibrated SiNWs FET sensor can accurately get the concentration results of the target in serum samples from patients with breast cancer. This work represents an important step toward the using of SiNWs FET sensor for accurate quantitative biochemical sensing and is expected to open up exciting opportunities for widely clinical application in the future.

Biosensing interface based on screen-printed carbon electrodes (SPCE) has been widely used for electrochemical biosensors in the field of medical diagnostics, food safety, and environmental monitoring. Nevertheless, SPCE always has a rough surface, which is easy to result in the disorder of nucleic acid capture probes, the nonspecific adsorption of signaling probes, the steric hindrance of target binding, and decrease in the signal-to-noise ratio and sensitivity of biosensors. So far, it still remains extremely challenging to develop high-efficiency carbon-based biosensing interfaces, especially for DNA probe-based assembly and functionalization. In this paper, we first used a specific DNA framework, DNA tetrahedron to solve the defects of the carbon interface, improving the biosensing ability of SPCE. With covalent coupling, the DNA tetrahedron could be immobilized on the carbon surface. Biosensing probe sequences extending from the DNA tetrahedron can be changed for different target molecules. We demonstrated that the improved SPCE could be applied for the detection of a variety of bioactive molecules. Typically, we designed gap hybridization, aptamer "sandwich" and aptamer competition reduction strategy for the detection of miRNA-141, thrombin, and ATP, respectively. High signal-to-noise ratio, sensitivity, and specificity were obtained for all of these kinds. Especially, the DNA tetrahedron-modified SPCE can work well with serum samples. The carbon-based DNA framework nano-bio interface would expand the use of SPCE and make electrochemical biosensors more available and valuable in clinical diagnosis.

Aiming at the problem of solder joint opening between front wheel cover plate and auxiliary water tank mounting bracket assembly in the process of PAVE test of a vehicle body structure, this paper finds out the failure reason of solder joint through structural stress analysis, and investigates several types of vehicle, combines CAE simulation analysis and vehicle’s own characteristic structure, puts forward two improved design schemes, considers each factor synthetically, and chooses the development scheme. A scheme with better cost and development cycle. The validation of the improved scheme shows that it not only effectively solders the solder joint opening problem between the front wheel cover plate and the auxiliary water tank mounting bracket assembly, meets the vehicle PAVE road test target requirements and improves the vehicle body reliability, but also takes into account the structural weight, setting cost and other factors, which is conducive to the lightweight design of the car body in white, and proves the effectiveness of the improved scheme.

Epigenetic alterations hold great promise as biomarkers for early stage cancer diagnosis. Nevertheless, direct identification of rare methylated DNA in the genome remains challenging. Here, we report an ultrasensitive framework nucleic acid-based electrochemical sensor for quantitative and highly selective analysis of DNA methylation. Notably, we can detect 160 fg of methylated DNA in million-fold unmethylated DNA samples using this electrochemical methylation-specific polymerase chain reaction (E-MSP) method. The high sensitivity of E-MSP enables one-step detection of low-abundance methylation at two different genes in patient serum samples. By using a combination test with two methylation alterations, we achieve high accuracy and sensitivity for reliable differentiation of prostate cancer and benign prostate hypertrophy (BPH). This new method sheds new light on translational use in early cancer diagnosis and in monitoring patients' responses to therapeutic agents.

In this study, we investigated the temporal association between carbapenems usage and antimicrobial resistance among major Gram-negative bacteria, using the data of quarterly carbapenems consumptions and percentages of antibiotic resistance for Gram-negative bacteria from inpatients from 2013 to 2017 in a tertiary hospital from Jiangsu Province, China. First, carbapenems consumption showed an increasing trend in the past 5 years, accompanied with the rising rates of A. baumannii and P. aeruginosa resistance against imipenem. In A. baumannii, we identified correlations between carbapenems consumption and antimicrobial resistance against piperacillin/tazobactam, ceftazidime, ciprofloxacin and imipenem, respectively. Additionally, close correlations were observed between carbapenems consumption and antimicrobial resistance against ceftazidime and ciprofloxacin in E. coli. Our data indicated that a significant positive correlation between the usage of carbapenems and the rate of antimicrobial resistance among A. baumannii and E. coli, respectively. Carbapenems should be cautiously prescribed to prevent antimicrobial resistance outbreak in A. baumannii and E. coli.

The practical applications of ZrC are restricted by its low fracture toughness and resistance to sintering densification. This study reports the in-situ precipitation behavior of (Zr,W)C solid solution precipitates induced by Ti. The (Zr0.7W0.3)C solid solution powder was prepared via carbothermic reduction using pressureless sintering at 2200 °C for 1 h. Varying quantities of TiH2 were reacted with the (Zr0.7W0.3)C matrix, to precipitate the second phase in-situ, via hot-pressing sintering (50 MPa) at 1600 °C for 1 h. When the content of TiH2 was 10 mol%, W and W2C were the second phases precipitated. As the TiH2 concentration increased, the precipitates converted into W2C and the (Ti,Zr)C solid solution. Furthermore, nano-scale dot-like W precipitates gradually increased inside the crystal grains of the (Zr,W,Ti)C matrix. The optimized comprehensive mechanical properties of (Zr,W,Ti)C-based multiphase ceramics were obtained by adding 40 mol% TiH2; the relative density was 99.7%, the Vickers hardness was 24.68 GPa, and the fracture toughness was 5.76 MPa·m1/2. The precipitates (of varying type and concentration) exhibited distinct toughening effects relative to the (Zr,W)C solid solution.