The robust detection of small targets is one of the key techniques in infrared search and tracking applications. A novel small target detection method in a single infrared image is proposed in this ...paper. Initially, the traditional infrared image model is generalized to a new infrared patch-image model using local patch construction. Then, because of the non-local self-correlation property of the infrared background image, based on the new model small target detection is formulated as an optimization problem of recovering low-rank and sparse matrices, which is effectively solved using stable principle component pursuit. Finally, a simple adaptive segmentation method is used to segment the target image and the segmentation result can be refined by post-processing. Extensive synthetic and real data experiments show that under different clutter backgrounds the proposed method not only works more stably for different target sizes and signal-to-clutter ratio values, but also has better detection performance compared with conventional baseline methods.
The viable but nonculturable (VBNC) state has been recognized as a strategy for bacteria to cope with stressful environments; in this state, bacteria fail to grow on routine culture medium but are ...actually alive and can resuscitate into a culturable state under favorable conditions. The VBNC state may pose a great threat to food safety and public health. To date, more than 100 VBNC microorganism species have been proven to exist in fields of food safety, environmental application, and agricultural diseases. Most harsh conditions can induce these microorganisms into the VBNC state, including food processing and preservation methods, adverse environmental conditions, and plant‐disease controlling means. The characteristics of VBNC state cells differ from those of normally growing cells and dead cells, based on which of the various detection methods are developed, and they are of great significance for potential risk assessment. To provide molecular level insights into this state, many studies on induction and resuscitation mechanisms have emerged over the past three decades, including research on omics, specific genes, or proteins involved in VBNC state formation and the roles of promoters in resuscitation from the VBNC state. In this review, microorganism species, induction and resuscitation factors, detection methods, and formation and resuscitation mechanisms of the VBNC state are comprehensively and systematically summarized.
Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), a well-known vanilloid, which is the main spicy component in chili peppers, showing several biological activities and the potential applications ...range from food flavorings to therapeutics. Traditional extraction of capsaicin by organic solvents was time-consuming, some new methods such as aqueous two-phase method and ionic liquid extraction method have been developed. During past few decades, an ample variety of biological effects of capsaicin have been evaluated. Capsaicin can be used in biofilms and antifouling coatings due to its antimicrobial activity, allowing it has a promising application in food packaging, food preservation, marine environment and dental therapy. Capsaicin also play a crucial role in metabolic disorders, including weight loss, pressure lowing and insulin reduction effects. In addition, capsaicin was identified effective on preventing human cancers, such as lung cancer, stomach cancer, colon cancer and breast cancer by inducing apoptosis and inhibiting cell proliferation of tumor cells. Previous research also suggest the positive effects of capsaicin on pain relief and cognitive impairment. Capsaicin, the agonist of transient receptor potential vanilloid type 1 (TRPV1), could selectively activate TRPV1, inducing Ca
2+
influx and related signaling pathways. Recently, gut microbiota was also involved in some diseases therapeutics, but its influence on the effects of capsaicin still need to be deeply studied. In this review, different extraction and purification methods of capsaicin, its biological activities and pharmacological effects were systematically summarized, as well as the possible mechanisms were also deeply discussed. This article will give an updated and better understanding of capsaicin-related biological effects and provide theoretical basis for its further research and applications in human health and manufacture development.
Chiral phosphoric acid-catalyzed enantioselective aza-Friedel–Crafts reaction of trifluoromethyl benzoxazinones with pyrroles is reported. Under mild conditions, a range of enantioenriched ...dihydrobenzoxazinones bearing trifluoromethylated quaternary stereocenters could be obtained in good to excellent yield and ee. A remarkable fluorine effect is observed, and preliminary mechanistic studies combined with theory calculations suggest that triple-hydrogen-bonding interactions hold the transition structure rigidly and allow the bulky substituents of the catalyst to influence the enantioselectivity.
Cell chirality has been demonstrated to be important for controlling cell functions. However, it is not clear how the chirality of the extracellular microenvironment regulates cell adhesion and ...cytoskeletal structures and therefore affects gene transfection. In this study, the chirality of focal adhesions and the cytoskeleton of single human mesenchymal stem cells (hMSCs) was controlled by specially designed micropatterns, and its influence on gene transfection was investigated. Micropatterns with different cell adhesion areas and swirling stripe lines were prepared by micropatterning fibronectin on polystyrene surfaces. The chiral micropatterns induced the formation of chiral focal adhesions and chiral cytoskeletal structures. Gene transfection efficiency was enhanced with increasing adhesion area, while hMSCs on left-handed and right-handed swirling micropatterns showed the same level of gene transfection. When the swirling angle was changed from 0°, 30°, and 60° to 90°, the gene transfection efficiency at a swirling angle of 60° was the lowest. The influence of cell chirality on gene transfection was strongly associated with cellular uptake capacity, DNA synthesis and cytoskeletal mechanics. The results demonstrated that cytoskeletal swirling had a significant influence on gene transfection.
Display omitted
•Chiral micropatterns were prepared from photo-reactive PVA through photolithography.•Cell chirality was controlled by the micropatterns.•The influence of cell chirality on exogenous gene transfection was investigated.•The swirling angle of cell chirality significantly affected transfection efficiency.•Different transfection efficiency was associated with cell mechanics and activity.
Accurately measuring the dielectric constant of soil and modeling it during freezing and thawing processes are important foundations of estimating the physical and chemical properties and moisture ...transfer characteristics of soil. In this study, a new test method was developed by combining five temperature probes and a 5TM sensor. Based on this method, a series of experiments for measuring the dielectric constant were conducted using silty clay as an example. The effects of freezing and thawing processes, water content, and salt on the dielectric constant of soil were comprehensively compared and analyzed. The results showed that the trends of soil dielectric constant as a function of temperature can be divided into a linear stage and a nonlinear stage. The soil dielectric constant measured during the freezing process was larger than that measured during the thawing process at the same negative temperature. However, the differences between them were related to the water content of the soil sample in the positive temperature range. In addition, the soil dielectric constant increased with the increase in water, NaCl, and K
2
SO
4
contents, which was particularly major in the positive temperature range. Finally, a new empirical model was proposed to calculate the dielectric constant of soil. The verification results demonstrated that the calculated dielectric constants agreed well with the measured results. This work can provide references for the measurement and prediction of soil dielectric constant.
Transmembrane transport of exogenous genes is widely investigated because of high demand for gene therapy. Both gene carriers and cellular conditions can affect gene transfection efficiency. Although ...cell morphology has been reported to affect cell functions, the influence of cell adhesion area and cell spreading area on the transfection of exogenous genes remains unclear because it is difficult to separate the individual influence of these areas during normal cell culture. In this study, micropatterns were prepared to separately control the adhesion and spreading areas of human bone marrow-derived mesenchymal stem cells (hMSCs). Transfection efficiency of the green fluorescent protein gene to hMSCs cultured on the micropatterns was compared. Cells with a larger adhesion area showed higher transfection efficiency, while cell spreading area hardly affected gene transfection efficiency. Cell adhesion area had dominant influence on gene transfection. Microparticle uptake and BrdU staining showed that the cellular uptake capacity and DNA synthesis activity increased with the increase in cell adhesion area, but were not affected by cell spreading area. The different influence of cell adhesion area and cell spreading area on gene transfection was correlated with their influence on cellular uptake capacity, DNA synthesis activity, focal adhesion formation, cytoskeletal mechanics, and mechanotransduction signal activation. The results suggest that cell adhesion area and cell spreading area had different influence on gene transfection; this finding should provide useful information for the manipulation of cell functions in gene therapy, protein modification, and cell reprogramming.
Cell adhesion and spreading are important morphological factors during the interaction of cells with biomaterial surfaces or interfaces. However, the predominant morphological factor that affects cellular functions such as gene transfection remains unclear. In the present study, special micropatterns were used to precisely control cell adhesion and spreading areas independently. Mesenchymal stem cells cultured on the micropatterns were transfected with the green fluorescent protein gene to compare the different influence of cell adhesion and spreading areas on gene transfection efficiency. Cell adhesion area showed dominant influence on gene transfection, while cell spreading area did not affect gene transfection. The dominant influence of cell adhesion area could be explained by cellular uptake capacity and DNA synthesis activity through the formation of FAs, cytoskeletal mechanics, and YAP/TAZ nuclear localization. The results provide new insights of correlation between cell morphology and cellular functions for designing functional biomaterials.
Display omitted
Abstract
The reduction of carbon dioxide using electrochemical cells is an appealing technology to store renewable electricity in a chemical form. The preferential adsorption of oxygen over carbon ...atoms of intermediates could improve the methanol selectivity due to the retention of C–O bond. However, the adsorbent-surface interaction is mainly related to the
d
states of transition metals in catalysts, thus it is difficult to promote the formation of oxygen-bound intermediates without affecting the carbon affinity. This paper describes the construction of a molybdenum-based metal carbide catalyst that promotes the formation and adsorption of oxygen-bound intermediates, where the
sp
states in catalyst are enabled to participate in the bonding of intermediates. A high Faradaic efficiency of 80.4% for methanol is achieved at −1.1 V vs. the standard hydrogen electrode.
In this paper, we present a nutrient solution control system, designing a nutrient solution electrical conductivity (EC) sensing system composed of multiple long-range radio (LoRa) slave nodes, ...narrow-band Internet of Things (NB-IoT) master nodes, and a host computer, building a nutrient solution EC control model and using the particle swarm optimization (PSO) algorithm to optimize the initial weights of a back-propagation neural network (BPNN). In addition, the optimized best weights are put into the BPNN to adjust the proportional–integral–derivative (PID) control parameters Kp, Ki, and Kd so that the system performance index can be optimized. Under the same initial conditions, we input EC = 2 mS/cm and use the particle swarm optimization BP neural network PID (PSO-BPNN-PID) to control the EC target value of the nutrient solution. The optimized scale factors were Kp = 81, Ki = 0.095, and Kd = 0.044; the steady state time was about 43 s, the overshoot was about 0.14%, and the EC value was stable at 1.9997 mS/cm–2.0027 mS/cm. Compared with the BP neural network PID (BPNN-PID) and the traditional PID control approach, the results show that PSO-BPNN-PID had a faster response speed and higher accuracy. Furthermore, we input 1 mS/cm, 1.5 mS/cm, 2 mS/cm, and 2.5 mS/cm, respectively, and simulated and verified the PSO-BPNN-PID system model. The results showed that the fluctuation range of EC was 0.003 mS/cm~0.119 mS/cm, the steady-state time was 40 s~60 s, and the overshoot was 0.3%~0.14%, which can meet the requirements of the rapid and accurate integration of water and fertilizer in agricultural production.
BACKGROUND: Changes in activity of polyphenol oxidase (PPO), peroxidase (POD) and β-glucosidase, individual phenolic compounds other than anthocyanins, total phenols, monomeric anthocyanins, ...polymeric color and instrumental color of strawberry pulps were assessed after high hydrostatic pressure (HHP) (400-600 MPa 5-25 min⁻¹) at room temperature. RESULTS: β-Glucosidase was activated by 4.7-16.6% at 400 MPa 5-25 min⁻¹ and inactivated by 8.0-41.4% at 500 or 600 MPa. PPO and POD were inactivated at all pressures, the largest reduction in activity being 41.4%, 51.5% and 74.6%, respectively. The individual phenolic compounds and total phenols decreased at 400 MPa, but total phenols increased at 500 or 600 MPa. However, the monomeric anthocyanins, polymeric color and redness (a*) exhibited no change. HHP induced a decrease in lightness (L*) and an increase in yellowness (b*) at 400 MPa, but no significant alteration in L* value and b* value at 500 or 600 MPa was observed; this was attributed to higher residual activity of PPO, POD and β-glucosidase at 400 MPa. Total color difference (ΔE) was ≥ 5 at 400 MPa and ⩽3 at 500 or 600 MPa. CONCLUSION: HHP effectively retained anthocyanins, phenolic compounds and color of strawberry pulps, and partly inactivated enzymes. Copyright
PDF
