Poor Homogeneity Research Articles

Effect of initial microstructure on microstructure and properties of bainitic steels achieved by rapid heat treatment

Rapid heat treatment is essential in manufacturing advanced high-strength steels. The initial microstructure significantly influences the steel's microstructure and properties after rapid heat treatment. The present study investigated how the initial microstructure affected phase transformation, microstructure, and properties of bainite in high-carbon low-alloy steel during rapid heat treatment. Under rapid heating, ultrafine bainite (UB) sample with homogeneous composition exhibits the lowest austenitization temperature, while globular pearlite (GP) sample with poor composition homogeneity has a higher austenitization temperature. After rapid heat treatment, the compositional distribution of the initial microstructure was partially retained in the final sample. The increase of alloying elements inhibits the nucleation of bainitic ferrite, making it easier for bainitic ferrite to grow at low-alloy positions. Finally, a large amount of retained austenite is obtained in the alloying element-rich area. The difference in microstructure results in samples with different initial microstructures having similar strengths but differing plasticities. In samples with an initial lamellar pearlite (LP) microstructure, there was a substantial amount of thicker, filmy retained austenite, with an average thickness of 96.8 nm. This led to a small increase in Kernel Average Misorientation (KAM) with strain during the tensile process. This improvement in coordinated deformation during straining indicates that the sample has achieved excellent performance, with a tensile strength of 1483 MPa and a uniform elongation of 23 %. When the initial microstructure was GP, the sample contained a large amount of crumbly retained austenite with a low aspect ratio. This structure poorly coordinated deformation with higher strain, resulting in numerous microcracks.

Microstructural Tuning of High‐Performance Bacterial Cellulose Anion Exchange Membranes via Constrained In Situ Polymerization and Double Chemical Cross‐Linking

AbstractHigh electrochemical and durability anion exchange membranes (AEMs) are a vital material for Flexible zinc‐air batteries (F‐ZAB) and AEM water electrolysis (AEMWE) to achieve green economy and environmental protection. However, the existing AEMs possess the disadvantages of a complicated preparation process, poor homogeneity, and unsatisfactory electrochemical performance. Here, a novel alkaline exchange membrane is synthesized using bacterial cellulose (BC) as the matrix, incorporating constrained in situ Poly (diallyldimethylammonium chloride) (PDDA) polymerization and double chemical cross‐linking techniques. By adjusting the microstructure, a unique long‐range order and dense internal structure to address the issue of loose bonding between PDDA and BC is established and achieve the purpose of rapid OH− conduction. The membranes exhibit excellent application properties, with excellent ionic conductivity (145.12 mS cm−1) and superb mechanical strength (73.26 MPa). Consequently, the membrane is assembled into the F‐ZAB, and the unprecedented power density of 258.7 mW cm−2 can be achieved at room temperature. Moreover, the membrane also can reach 3.0 A cm−2 at 2.3 V, indicating good prospects in the field of water electrolysis in 6 m KOH. The approach paves a new path for manufacturing AEMs for green energy and environmental applications.

Ultra-low-field magnetization transfer imaging at 0.055T with low specific absorption rate.

To demonstrate magnetization transfer (MT) effects with low specific absorption rate (SAR) on ultra-low-field (ULF) MRI. MT imaging was implemented by using sinc-modulated RF pulse train (SPT) modules to provide bilateral off-resonance irradiation. They were incorporated into 3D gradient echo (GRE) and fast spin echo (FSE) protocols on a shielding-free 0.055T head scanner. MT effects were first verified using phantoms. Brain MT imaging was conducted in both healthy subjects and patients. MT effects were clearly observed in phantoms using six SPT modules with total flip angle 3600° at central primary saturation bands of approximate offset ±786 Hz, even in the presence of large relative B0 inhomogeneity. For brain, strong MT effects were observed in gray matter, white matter, and muscle in 3D GRE and FSE imaging using six and sixteen SPT modules with total flip angle 3600° and 9600°, respectively. Fat, cerebrospinal fluid, and blood exhibited relatively weak MT effects. MT preparation enhanced tissue contrasts in T2-weighted and FLAIR-like images, and improved brain lesion delineation. The estimated MT SAR was 0.0024 and 0.0008 W/kg for two protocols, respectively, which is far below the US Food and Drug Administration (FDA) limit of 3.0 W/kg. Robust MT effects can be readily obtained at ULF with extremely low SAR, despite poor relative B0 homogeneity in ppm. This unique advantage enables flexible MT pulse design and implementation on low-cost ULF MRI platforms to achieve strong MT effects in brain and beyond, potentially augmenting their clinical utility in the future.

Atomic layer deposition of Al-doped ZnO nanomembrane with in situ monitoring

Due to shortcomings such as poor homogeneity of Al doping, precisely controlling the thickness, inability to conformally deposit on high aspect ratio devices and high pinhole rate, the applications of Al-doped ZnO (AZO) nanomembrane in integrated optoelectronic devices are remarkably influenced. Here, we report in situ monitoring during the atomic layer deposition (ALD) of AZO nanomembrane by using an integrated spectroscopic ellipsometer. AZO nanomembranes with different compositions were deposited with real-time and precise atomic level monitoring of the deposition process. We specifically investigate the half-reaction and thickness evolution during the ALD processes and the influence of the chamber temperature is also disclosed. Structural characterizations demonstrate that the obtained AZO nanomembranes without any post-treatment are uniform, dense and pinhole-free. The transmittances of the nanomembranes in visible range are >94%, and the optimal conductivity can reach up to 1210 S cm−1. The output of current research may pave the way for AZO nanomembrane to become promising in integrated optoelectronic devices.

White-light activatable organic NIR-II luminescence nanomaterials for imaging-guided surgery

While second near-infrared (NIR-II) fluorescence imaging is a promising tool for real-time surveillance of surgical operations, the previously reported organic NIR-II luminescent materials for in vivo imaging are predominantly activated by expensive lasers or X-ray with high power and poor illumination homogeneity, which significantly limits their clinical applications. Here we report a white-light activatable NIR-II organic imaging agent by taking advantages of the strong intramolecular/intermolecular D-A interactions of conjugated Y6CT molecules in nanoparticles (Y6CT-NPs), with the brightness of as high as 13315.1, which is over two times that of the brightest laser-activated NIR-II organic contrast agents reported thus far. Upon white-light activation, Y6CT-NPs can achieve not only in vivo imaging of hepatic ischemia reperfusion, but also real-time monitoring of kidney transplantation surgery. During the surgery, identification of the renal vasculature, post-reconstruction assessment of renal allograft vascular integrity, and blood supply analysis of the ureter can be vividly depicted by using Y6CT-NPs with high signal-to-noise ratios upon clinical laparoscopic LED white-light activation. Our work provides efficient molecular design guidelines towards white-light activatable imaging agent and highlights an opportunity for precision imaging theranostics.

Optimization of tracheoesophageal fistula model established with T-shaped magnet system based on magnetic compression technique.

The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula (TEF), but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control. We designed a T-shaped magnet system to overcome these problems and verified its effectiveness via animal experiments. To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs. Twelve beagles were randomly assigned to groups in which magnets of the T-shaped scheme (study group, n = 6) or normal magnets (control group, n = 6) were implanted into the trachea and esophagus separately under gastroscopy. Operation time, operation success rate, and accidental injury were recorded. After operation, the presence and timing of cough and the time of magnet shedding were observed. Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing, and gross specimens of TEFs were obtained. Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery, and gross specimens were obtained. Fistula size was measured in all animals, and then harvested fistula specimens were examined by hematoxylin and eosin (HE) and Masson trichrome staining. The operation success rate was 100% for both groups. Operation time did not differ between the study group (5.25 min ± 1.29 min) and the control group (4.75 min ± 1.70 min; P = 0.331). No bleeding, perforation, or unplanned magnet attraction occurred in any animal during the operation. In the early postoperative period, all dogs ate freely and were generally in good condition. Dogs in the control group had severe cough after drinking water at 6-9 d after surgery. X-ray indicated that the magnets had entered the stomach, and gastroscopy showed TEF formation. Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm ± 1.29 mm (range, 3.52-6.56 mm). HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas. Dogs in the study group did not exhibit obvious coughing after surgery. X-ray examination 2 wk after surgery indicated fixed magnet positioning, and gastroscopy showed no change in magnet positioning. The magnets were removed using a snare under endoscopy, and TEF was observed. Gross specimens showed well-formed fistulas with a diameter of 6.11 mm ± 0.16 mm (range, 5.92-6.36 mm), which exceeded that in the control group (P < 0.001). Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining, and the structure was more regular than that in the control group. Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets. Most importantly, this model offers better controllability, which improves the flexibility of follow-up studies.

Surface Energy-Assisted Patterning of Vapor Deposited All-Inorganic Perovskite Arrays for Wearable Optoelectronics.

Solution-based methods for fabricating all-inorganic perovskite film arrays often suffer from limited control over nucleation and crystallization, resulting in poor homogeneity and coverage. To improve film quality, advanced vapor deposition techniques are employed for continuous film. Here, the vapor deposition strategy to the all-inorganic perovskite films array, enabling area-selective deposition of perovskite through substrate modulation is expanded. It can yield a high-quality perovskite film array with different pixel shapes, various perovskite compositions, and a high resolution of 423dpi. The resulting photodetector arrays exhibit remarkable optoelectronic performance with an on/off ratio of 13 887 and responsivity of 47.5AW-1. The device also displays long-term stability in a damp condition for up to 12h. Moreover, a pulse monitoring sensor based on the perovskite films array demonstrates stable monitoring for pulse signals after being worn for 12h and with a low illumination of 0.055mWcm-2, highlighting the potential application in wearable optoelectronic devices.

Optimizing cell deposition for inkjet-based bioprinting

Although inkjet-based bioprinting enables precise drop-on-demand cell deposition within three-dimensional (3D) tissue constructs and facilitates critical cell&amp;ndash;cell and cell&amp;ndash;matrix interactions, it faces challenges such as poor cell homogeneity and low cell viability. To date, there is a lack of comprehensive review papers addressing the optimization of cell deposition in inkjet-based bioprinting. This review aims to fill that gap by providing an overview of various critical aspects in bioprinting, ranging from bio-ink properties to the impact of printed droplets. The bio-ink section begins by exploring how cells influence the physical properties of bio-inks and emphasizes the significance of achieving cell homogeneity within bio-inks to ensure consistent and reliable printing. The discussion then delves into inkjet-based printing chambers (thermal and piezoelectric), the effect of shear stress on printed cells, droplet formation dynamics, the influence of polymer-based and cell-laden droplets on the underlying substrate surface, and the dynamics of droplet impact. Beyond droplet formation and impact, the review highlights the importance of biophysical and biological cues within 3D hydrogel matrices for cell proliferation and differentiation. Finally, the paper highlights current and potential applications, with a specific focus on skin and lung tissue engineering using inkjet-based bioprinting techniques, and provides insights into the emerging role of machine learning in optimizing the cell deposition process for inkjet-based bioprinting.

Editors’ Choice—Alleviating the Kinetic Limitations of the Li-In Alloy Anode in All-Solid-State Batteries

Li-In electrodes are widely applied as counter electrodes in fundamental research on Li-metal all-solid-state batteries. It is commonly assumed that the Li-In anode is not rate limiting, i.e. the measurement results are expected to be representative of the investigated electrode of interest. However, this assumption is rarely verified, and some counterexamples were recently demonstrated in literature. Herein, we fabricate Li-In anodes in three different ways and systematically evaluate the electrochemical properties in two- and three-electrode half-cells. The most common method of pressing Li and In metal sheets together during cell assembly resulted in poor homogeneity and low rate performance, which may result in data misinterpretation when applied for investigations on cathodic phenomena. The formation of a Li-poor region on the separator side of the anode is identified as a major kinetic bottleneck. An alternative fabrication of a Li-In powder anode resulted in no kinetic benefits. In contrast, preparing a composite from Li-In powder and sulfide electrolyte powder alleviated the kinetic limitation, resulted in superior rate performance, and minimized the impedance. The results emphasize the need to fabricate optimized Li-In anodes to ensure suitability as a counter electrode in solid-state cells.

Comprehensive and full-cycle cancer health management

In order to realize the "Healthy China 2030" strategic plan, it is necessary to create a new model of all-round and full-cycle cancer health management in line with China's national conditions and the characteristics of the times. Comprehensively strengthen the construction of the whole-chain tumor prevention and control system, shift the front of cancer prevention and treatment to the precancerous cycle, and realize the full-cycle management of accurate screening, regular follow-up, early diagnosis, early treatment and rehabilitation follow-up of cancer patients; all-round interdisciplinary cooperation, strengthen the management of patients with accompanying diseases, and encourage patients to return to society and families in the best condition; comprehensively deploy tumor big data and smart medical care, promote the construction of Internet outpatient clinics and regional medical centers, and develop a three-level linkage palliative care model, Solve a series of problems such as shortage of medical resources and poor homogeneity of medical care.

턱관절 장애에 대한 근에너지 기법의 효과

Objectives : This study aimed to conduct a systematic review evaluating the effec- tiveness of muscle energy technique(MET) in temporomandibular joint disorders (TMD).&#x0D; Methods : Searches were conducted in 11 electronic databases until October 2023. Randomized controlled trials(RCT) comparing the effect of MET for TMD were included. All studies were evaluated using the Cochrane Risk of Bias tool.&#x0D; Results : Nine documents that fulfilled all the criteria were obtained for analysis. All studies showed some concerns in high risk of bias, but showed a significant improve- ment in pain and maximum mouth opening compared to baseline of MET or control group. MET was not better than extracorporeal shock wave therapy or myofascial re- lease in some outcomes.&#x0D; Conclusions : MET seems to be an effective treatment for TMD in some regards, however, can be considered as an adjunct therapy which has weak evidence. Further studies are required due to the inconclusive data and poor homogeneity found in this review.

Synthesis of a homogeneous CeO2–ZrO2-Al2O3 composite material by a novel hydrothermal assisted precipitation method

CeO2-ZrO2-Al2O3(CZA) composites, combining the advantages of CeO2-ZrO2 (CZ) and Al2O3, are widely used in three-way catalyst as an indispensable support material. However, due to the adverse Zr-Al interaction and the different precipitation conditions for Ce3+/Ce4+ and Zr4+, the CZA prepared by conventional co-precipitation method has poor compositional homogeneity, resulting in degradation of redox properties. In this study, a homogeneous CZA composite is synthesized by a novel hydrothermal assisted precipitation method, in which the CZ-precipitates and Al-precipitates will be controlled separately. A quantitative EDX points analysis reveals that the Ce/Zr ratio in the resulting CZA material exhibits slight fluctuations between 0.72 and 0.91, which is much narrow than that from conventional precipitation method (0.38∼0.83). As a result, the resulting CZA material exhibits the better redox property, higher specific surface area, and more importantly, its supported Pd/CZA catalyst exhibit superior three-way catalytic activity, the T50 (temperature for 50% conversion) for CO, NO, C3H6 and C3H8 over which is 41 ℃, 26 ℃, 28 ℃ and 12 ℃, respectively, lower than that from conventional method.

Concordance of ctDNA and tissue mutations in NSCLC: A meta-analysis.

Systematic evaluation of the consistency between circulating tumor DNA (ctDNA) in plasma and tumor tissue samples in mutations in non-small cell lung cancer (NSCLC) patients. To collect publicly published literature from numerous important international medical databases through computer retrieval. To compare the differences in literature data related to gene mutations between plasma ctDNA and tumor tissue samples, a meta-analysis was performed using Stata 12.0 software while taking into account the inclusion and exclusion criteria. This article includes a total of 15 research data and collected data reports from 15 groups of NSCLC patients. The results are displayed using tissue samples as the gold standard. The Pearson correlation coefficients of sensitivity and specificity were used to calculate rho=0.044, and P=0.893. The Q-test found poor homogeneity and high heterogeneity in sensitivity and specificity among research data from various literature studies (I2>50%, P<0.1). The area under the SROC curve is 0.97 (95% CI: 0.96~0.99). The small sample subgroup has high heterogeneity, and the combined diagnosis effect size is 26[6~111], lower than the large sample subgroup 185320 [0~2.7×1012]. When taking 200 as the cut-off point, the combined effect size of the small sample subgroup is 46 [12~183], still lower than that of the large sample subgroup 429 [52~3574]. From this, it can be concluded that the consistency of small-sample studies is higher than the quality of large-sample studies, and the heterogeneity is relatively low. From the perspective of mutation types, the heterogeneity of literature with EGFR gene mutations alone is higher than that of literature with non-EGFR mutations alone, and the consistency is lower. The consistency of using plasma ctDNA to detect mutations in NSCLC patients with tumor tissue samples is influenced by the type of mutation gene and sample size measured by the patient, and there is a significant bias in related studies.

Assessment of deep levels with selenium concentration in Cd1–xZnxTe1–ySey room temperature detector materials

Incorporation of Se into Cd1−xZnxTe (CZT) to form the quaternary compound semiconductor Cd1−xZnxTe1–ySey (CZTS) has proven to be an effective solution for compensating the major flaws associated with CZT, including poor homogeneity and high concentrations of electronically active deep levels that limit the performance of CZT detectors. In order to investigate how deep levels are affected by the Se concentration in CZTS, we performed photoinduced current transient spectroscopy (PICTS) measurements on CZTS crystals grown by the traveling heater method (THM) with 10% atomic Zn and varying atomic percentage of Se from 1.5% to 7.0%. The PICTS scans for up to 4% Se showed an exponential reduction in the capture cross section of deep levels associated with Te secondary phases in conjunction with an increase in a deep level positioned near the mid-gap, which initially increases the electron trapping time before degrading again at higher Se concentrations. The PICTS peaks present in 7% Se were anomalous relative to the other crystals and are expected to originate from transition metal impurities found in the lower-purity CdSe precursor material.

Workability Properties of Specified Density Concrete with Municipal Solid Waste Incinerator Tailings Added as a Lightweight Aggregate

The application of municipal solid waste incineration tailings lightweight aggregate (MSWI-TLA) for reducing carbon emissions, energy consumption, and environmental pollution of bulk solid waste treatment has received extensive attention. As a new type of green lightweight aggregate, MSWI-TLA exhibits considerably good performance and broad prospects; however, its working performance in cement-based materials is not as good as that of ordinary aggregates. In this study, a standardized municipal solid waste incineration tailings lightweight fine aggregate (MSWI-TLFA) with a fineness modulus of 3.1 and a municipal solid waste of 10 mm were utilized as substitutes for the common aggregate. The incineration tailings lightweight coarse aggregate (MSWI-TLCA) with the particle size ranging from 5 to stirring process and the fluidity and filling properties were improved, and stratification was slowed down. Based on the slump, fluidity, and stratification data of municipal solid waste incineration tailings lightweight aggregate specific density concrete (MSWI-TLA-SDC), the internal and external stacking structure model, matrix density three-phase diagram, and stratification function relationship were established, and the formation mechanism of fluidity and homogeneity under the synergistic effect of MSWI-TLA-SDC matrix density was revealed. Simultaneously, the qualitative analysis of homogeneity was carried out intuitively and visualized using computed tomography (CT) technology, and the accurate quantitative analysis model of stratification degree and aggregate separation factor was established using the principle of fluid mechanics, and the optimization effect was verified. The results show that the fluidity of MSWI-TLA-SDC decreases by 3.3%–30.5% and the delamination degree increases by 4.9%–22.9% compared with ordinary concrete. The main reason for the poor fluidity and homogeneity of MSWI-TLA-SDC is the poor density synergy between tailings lightweight aggregate, ordinary aggregate, and mortar matrix. The preabsorbed gravel-type small-size tailings lightweight aggregate along with technical measures like combining water-reducing agent, fine tailings aggregate, and tailings powder can be used to reduce the difference in matrix density and fully exploit the synergistic effects of matrix density. For the closed-loop absorption of tailings lightweight aggregate as well as the technical advancement and promotion of MSWI-TLA-SDC, it is crucial to increase the fluidity and homogeneity of MSWI-TLA-SDC.

Manufacture and rheological behavior of all recycled PET/PP microfibrillar blends

AbstractFor several years, new plastic bottles made from opaque polyethylene terephtalate (PET) have been on the market. When their waste is mixed to those of recycled clear PET, the obtained material cannot be recycled anymore due to a loss of properties. Moreover, because of an important grade variety, the large number of additives used and poor homogeneity, the processing and recycling of opaque PET appears as a challenge. The way chosen to revalue this recycled opaque PET (r‐OPET) is its microfibrillation in a recycled polypropylene (rPP) matrix. The effects of the concentration of r‐OPET were studied by rheology, supported by scanning electron microscope images and related to the morphology of the mixture. It was demonstrated that (20/80)w r‐OPET/rPP blend was the best ratio to favor microfibrillation, as it offers the appropriate amount of solid filler to obtain a sea‐island morphology.Thereafter, the influence of the temperature of microfibrillation is presented. The thermomechanical curve of the (20/80)w r‐OPET/rPP blend suggests that microfibrillation should be more effective around the Tg of r‐OPET. The optimum temperature was found, where an improvement of rheological and mechanical properties is observed. A Cross model with yield stress is proposed to describe the rheological behavior of this material.

Synthesis of a nanosized homogeneous Al2O3–CeO2–ZrO2 composite as an oxygen-storage material for highly improved thermal durability

Al2O3–CeO2–ZrO2 (ACZ) is widely used in automotive catalysts as an oxygen-storage material. However, ACZ prepared by conventional synthesis methods has poor compositional homogeneity, resulting in thermal degradation of the oxygen storage capacity (OSC) because of the sintering of CeO2–ZrO2 (CZ) crystals. In this study, a nanosized homogeneous ACZ composite is synthesized by an improved co-precipitation method that uses a high-shear agitation reactor and a polyamine dispersant. The sol obtained using the abovementioned method is a monodisperse colloid with an average particle size of 3.2 nm. A quantitative analysis of transmission electron microscopy images reveals that the distribution of Al2O3 and CZ after calcination at 500 °C is 1.6 times more homogeneous in the resulting ACZ than that in the ACZ powder obtained by conventional co-precipitation. Such excellent homogeneity of Al2O3 and CZ distribution results in smaller CZ crystals (11.2 nm) than the conventional one (14.6 nm) obtained after calcination at 1100 °C. The smaller CZ crystals have 1.3 times higher OSC than that of the conventional one. Therefore, the developed method yields homogeneous and thermally stable ACZ that can be used as an efficient automotive catalyst. Furthermore, this method would also be useful for synthesizing homogeneous nano-composites with various elemental combinations.

Large-area flexible colloidal-quantum-dot infrared photodiodes for photoplethysmogram signal measurements

Epitaxially grown photodiodes are the foundation of infrared photodetection technology; however, their rigid structure and limited area scaling limit their use in advanced applications. Colloidal-quantum-dot (CQD) infrared photodiodes have increased active areas through solution processing, and are thus potential candidates for large-area flexible photodetection, but these large-area photodiodes have disadvantages such as large dark current density, poor homogeneity, and poor stability. Therefore, this study established a fabrication strategy for large-area flexible CQD photodiodes that involves introducing polyimide to CQD ink to improve CQD passivation, monodisperse ink persistence, and film morphology. The resulting CQD photodiodes exhibited reduced dark current density and improved homogeneity and work stability. Furthermore, the as-prepared photodiodes exhibited a detectivity (D*) of greater than 1013 Jones, which was higher than other reported CQD photodetectors. The CQD photodiodes developed in this study can be used for wearable photoplethysmogram (PPG) signal measurement under ambient light at reduced cost and power consumption.

Tandem Multimerization Can Enhance the Structural Homogeneity and Antifungal Activity of the Silkworm Protease Inhibitor BmSPI39

Previous studies have shown that BmSPI39, a serine protease inhibitor of silkworm, can inhibit virulence-related proteases and the conidial germination of insect pathogenic fungi, thereby enhancing the antifungal capacity of Bombyx mori. The recombinant BmSPI39 expressed in Escherichia coli has poor structural homogeneity and is prone to spontaneous multimerization, which greatly limits its development and application. To date, the effect of multimerization on the inhibitory activity and antifungal ability of BmSPI39 remains unknown. It is urgent to explore whether a BmSPI39 tandem multimer with better structural homogeneity, higher activity and a stronger antifungal ability can be obtained by protein engineering. In this study, the expression vectors of BmSPI39 homotype tandem multimers were constructed using the isocaudomer method, and the recombinant proteins of tandem multimers were obtained by prokaryotic expression. The effects of BmSPI39 multimerization on its inhibitory activity and antifungal ability were investigated by protease inhibition and fungal growth inhibition experiments. In-gel activity staining and protease inhibition assays showed that tandem multimerization could not only greatly improve the structural homogeneity of the BmSPI39 protein, but also significantly increase its inhibitory activity against subtilisin and proteinase K. The results of conidial germination assays showed that tandem multimerization could effectively enhance the inhibitory ability of BmSPI39 on the conidial germination of Beauveria bassiana. A fungal growth inhibition assay showed that BmSPI39 tandem multimers had certain inhibitory effects on both Saccharomyces cerevisiae and Candida albicans. The inhibitory ability of BmSPI39 against these the above two fungi could be enhanced by tandem multimerization. In conclusion, this study successfully achieved the soluble expression of tandem multimers of the silkworm protease inhibitor BmSPI39 in E. coli and confirmed that tandem multimerization can improve the structural homogeneity and antifungal ability of BmSPI39. This study will not only help to deepen our understanding of the action mechanism of BmSPI39, but also provide an important theoretical basis and new strategy for cultivating antifungal transgenic silkworms. It will also promote its exogenous production and development and application in the medical field.

Miniature Hierarchical DNA Hybridization Circuit for Amplified Multiplexed MicroRNA Imaging.

Accurate diagnosis requires the development of multiple-guaranteed DNA circuits. Nevertheless, for reliable multiplexed molecular imaging, existing DNA circuits are limited by poor cell-delivering homogeneity due to their cumbersome and dispersive reactants. Herein, we developed a compact-yet-efficient hierarchical DNA hybridization (HDH) circuit for in situ simultaneous analysis of multiple miRNAs, which could be further exploited for specifically discriminating cancer cells from normal ones. By integrating the traditional hybridization chain reaction and catalytic hairpin assembly reactants into two highly organized hairpins, the HDH circuit is fitted with condensed components and multiple response domains, thus permitting the programmable multiple microRNA-guaranteed sequential activations and the localized cascaded signal amplification. The synergistic multi-recognition and amplification features of the HDH circuit facilitate the magnified detection of multiplex endogenous miRNAs in living cells. The in vitro and cellular imaging experimental results revealed that the HDH circuit displayed a reliable sensing performance with high selective cell-identification capacity. We anticipate that this compact design can provide a powerful toolkit for accurate diagnostics and pathological evolution.