Passive source localization based on multipath arrival angles with a vertical line array using sparse Bayesian learning.

In deep water, multipath time delays or frequency-domain interference periods of the acoustic intensity combined with multipath arrival angles are typically used for source localization. However, depth estimate is hard to achieve for a narrowband source at a remote part of the direct arrival zone as the required bandwidth increases with the source range. In this paper, a passive source localization method with a vertical line array, suitable for both broadband and narrowband sources, is proposed. Based on the variation trends of multipath angles with source range and depth, source localization is achieved by only matching the measured angles of the direct path and surface-reflected path with model-based values of a predefined grid of potential source locations. Considering the angle resolution limited by the array aperture and the presence of coherent multipath, sparse Bayesian learning is used and compared with the conventional beamforming and the minimum-variance distortionless-response beamforming to resolve and estimate the multipath angles. Simulations and experimental data of explosive sources collected by a vertical line array in the South China Sea are carried out to illustrate the method and demonstrate the performance.

Biomechanical improvement of anterior talofibular ligament by augmentation repair of ligament advance reinforcement system: a cadaver study.

BACKGROUND: Ankle sprain are one of the most frequent sports injuries. Some individuals will develop chronic lateral ankle instability (CLAI) after ankle sprain and suffer from recurrent ankle sprain. Current surgical treatment of CAI with anterior talofibular ligament (ATFL) rupture fails to restore the stability of the native ATFL. Ligament Advance Reinforcement System (LARS) augmentation repair of ATFL was developed to improve its primary stability after repaired. METHODS: This study was performed to evaluate whether LARS augmentation repair of ATFL had similar stability as the modified Broström repair and the intact ATFL to maintain ankle construct stability. Standardized surgical techniques were performed on eighteen fresh frozen cadaver ankle specimens. The intact ATFL group has just undergone an ATFL exploratory surgery. The modified Broström procedure is based on anatomical repair of the ATFL with a 2.9 mm suture anchor, and the LARS procedure is an augmentation procedure of the ATFL using LARS ligaments based on the modified Broström procedure. A dynamic tensile test machine was used to assess load-to-failure testing in the three groups. The ultimate failure load and stiffness were calculated and reported from the load-displacement curve. A one-way analysis of variance was used to detect significant differences (p < 0.05) between the LARS augmentation repair, the modified Broström repair and the intact ATFL, followed by least significant difference (LSD) post-hoc tests. RESULTS: The LARS augmentation repair group showed an increased in ultimate failure to load and stiffness compared to the other two groups. There were no significant differences in ultimate failure to load and stiffness between the modified Broström and the intact ATFL, the LARS ligament for ATFL augmentation allows for improved primary stability after repair and reduced stress on the repaired ATFL, which facilitates healing of the remnant ligament. CONCLUSIONS: The LARS augmentation repair of ATFL represents a stable technique that may allow for the ankle stability to be restored in patients with CAI after surgery.

A sensitive multimode dot-filtration strip for the detection of Salmonella typhimurium using MoS2@Fe3O4.

A sensitive, accurate, and rapid multimode dot-filtration immunoassay (MDFIA) was established for the detection of Salmonella typhimurium using the intrinsic color, catalytic property, and photothermal effect of magnetic molybdenum disulphide (MoS2@Fe3O4). The critical performance parameters of MDFIA were optimized in detail. The sensitivity of MDFIA can be improved by the catalytic color development and photothermal conversion of MoS2@Fe3O4 with a limit of detection (LOD) of 101 CFU·mL-1, which is an order of magnitude lower than direct visual detection (102 CFU·mL-1). Besides, the magnetic property of MoS2@Fe3O4 was used for the rapid enrichment and separation of the target allowing detection of trace concentrations of Salmonella typhimurium. The selectivity and applicability of the MDFIA were verified in spiked samples, indicating that the established assay may have bright application prospects for the detection and control of foodborne pathogens. A multimode dot-filtration immunoassay was constructed for Salmonella typhimurium rapid detection based on the peroxidase-like activity, magnetic property, and photothermal effect of MoS2@Fe3O4.

Passive broadband source depth estimation in the deep ocean using a single vector sensor.

For an acoustic receiver deployed at the bottom of the direct arrival zone of a submerged source at short horizontal ranges in deep ocean, the interference pattern of the direct and surface-reflected acoustic arrivals shows periodic modulation, which is directly related to the source depth, source frequency, and vertical arrival angle. In this work, the interference cycle presented in the frequency domain is used to extract the broadband source depth, with the vertical arrival angle obtained from the ratio of vertical acoustic intensity and horizontal acoustic intensity from the signal recorded by a single vector sensor. Experimental results demonstrate the source depth estimation without requiring knowledge of the ocean environment.

Observation and inversion of very-low-frequency seismo-acoustic fields in the South China Sea.

Very-low-frequency (VLF) sound has significant potential for underwater detection and estimation of geoacoustic models of the ocean bottom structure. In marine settings, one type of VLF sound is the interface wave. These waves, trapped near the fluid-solid interface, are called Scholte waves, and this is the subject of this study. A field experiment was carried out in the South China Sea with the objective of exciting Scholte waves and investigating the propagation. The data were acquired by an ocean bottom seismometer, deployed on the seafloor. A large volume airgun array near the sea surface provided the sound source. The fundamental and three higher-order mode Scholte waves were excited. The Scholte waves are investigated by seismograms and a phase velocity inversion. The observed frequencies are in the range of 1.0-2.9 Hz. The energy attenuation is proportional to 1/r at the peak frequency 1.4 Hz. The shear wave speed structure, down to 600 m beneath the seafloor, is revealed from the dispersion curves by a least-squares inversion algorithm. The inversion result shows that the shear wave speed is below 300 m/s in the uppermost layer, which explains well the weak excitation of Scholte waves in this experiment.

Salmonella typhimurium detector based on the intrinsic peroxidase-like activity and photothermal effect of MoS2.

A multimode dot-filtration immunoassay (MDFIA) was established for rapid and accurate detection of the target (Salmonella typhimurium), which was based on the intrinsic color, peroxidase-like activity and photothermal effect of molybdenum disulfide (MoS2). Obviously, multimode detection can improve detection accuracy compared to the direct visual detection in test strips. A thermal imaging camera was used as detector to record the temperature change (ΔT) of MoS2 and establish the standard curve of ΔT and the concentration of Salmonella typhimurium to realize quantitative determination. The main parameters that affect the analytical performance of MDFIA were optimized. Under the optimal experimental conditions, the limit of detection (LOD) of photothermal detection reached 102 CFU mL-1 and was one order of magnitude lower than the limit of direct visual detection and catalytic color development detection (103 CFU mL-1). The accuracy and analytical sensitivity were enhanced by intrinsic peroxidase-like activity and the huge photothermal effect of MoS2. Moreover, this method exhibited high selectivity, good repeatability, and acceptable stability and the entire process was simple to be accomplished in 30 min, which generally meets the need of rapid detection. The successful implementation in real samples with the recovery being between 99.5 and 119.2% showed that it could be used as a promising quality control strategy for detection of other foodborne pathogens. The peroxidase-like activity and excellent photothermal effect of MoS2 was used to develop a multimode dot-filtration immunoassay for rapid detection of Salmonella typhimurium.

Nano-gold capillary immunochromatographic assay for parvalbumin.

A novel non-instrumental bioanalysis based on colloidal-gold immunochromatography in a modified glass capillary was developed and named capillary immunochromatographic assay (CICA). In this report, glass capillary was proposed as a support in immunochromatographic assay because of its excellent characteristics. Goat anti-rabbit IgG and parvalbumin (PV) were immobilized on the inner wall of the glass capillary as control zone and test zone, respectively. The CICA was constructed, and main variables for the performance were optimized. Using an important allergen of fish products (parvalbumin, PV) as the target, the analytical efficiency of the developed technique was investigated and the visual detection limit (VDL) and semi-quantitative limit of detection (LOD) were estimated to be 70 ng mL(-1) and 40 ng mL(-1), respectively. The coefficient of variation (CV) for the intra-assay and inter-assay was calculated for the PV concentration of 50 ng mL(-1), and the entire operation, including sample preparation, was consistently performed in 30 min. The developed technique was implemented and validated with different foodstuffs, including Scophthalmus maximus (Linnaeus), surimi products, and livestock, confirming sufficient accuracy and precision of results and verifying the method to be efficacious. These results enabled us to propose CICA as a new and promising technique for simple, rapid, and on-site screening of PV in biological samples.

A gas-driven capillary based on the synergy of the catalytic and photothermal effect of PB@Au for Salmonella typhimurium detection.

Rapid detection method for Salmonella typhimurium is vital to prevent the spread of food-borne diseases. In this work, a gas-driven capillary detection method was established to achieve sensitive and rapid detection of Salmonella typhimurium using the catalytic and photothermal synergy of Prussian blue-nanogold (PB@Au) nanomaterials. The immuno-PB@Au probe attached to the capillary by specific identification of target bacteria catalyzed the H2O2 under laser irradiation, driving the H2O2 liquid column to move (ΔL) by producing gas, and achieving the quantitative detection of Salmonella typhimurium. After detailed optimization of the critical performance parameters of the gas-driven capillary assay, the limit of detection (LOD) after laser irradiation and being catalyzed by PB@Au was calculated to be 37 CFU mL-1 through the determination of different concentrations of target bacteria. Furthermore, the detection performances of the gas-driven capillary method were evaluated in detail, and the recoveries ranging from 92.9 ± 4.7 % to 107.7 ± 4.1 % were achieved using the spiked actual samples with complex matrices, indicating that the established rapid assay can offer promising strategies for the monitoring and controlling of food-borne pathogenic bacteria.

Selection and application of highly specific Salmonella typhimurium aptamers against matrix interference.

In practical applications, the structure and performance of aptamers can be influenced by the presence of sample matrices, which interferes with the specific binding between the aptamer and its target. In this work, to obtain aptamer chains resistant to matrix interference, four typical food matrices were introduced as negative selection targets and selection environments in the process of selecting aptamers for Salmonella typhimurium using the systematic evolution of ligands by exponential enrichment (SELEX) technology. As a result, some highly specific candidate aptamers for Salmonella typhimurium (BB-34, BB-37, ROU-8, ROU-9, ROU-14, ROU-24, DAN-3, NAI-12, and NAI-21) were successfully obtained. Based on the characterization results of secondary structure, affinity, and specificity of these candidate aptamers, ROU-24 selected in the pork matrix and BB-34 selected in the binding buffer were chosen to develop label-free fluorescence aptasensors for the sensitive and rapid detection of the Salmonella typhimurium and verify the performance against matrix interference. The ROU-24-based aptasensor demonstrated a larger linear range and better specificity compared to the BB-34-based aptasensor. Meanwhile, the recovery rate of the ROU-24-based aptasensor in real sample detection (ranging from 94.2% to 110.7%) was significantly higher than that of the BB-34-based aptasensor. These results illustrated that the negative selection of food matrices induced in SELEX could enhance specific binding between the aptamer and its target and the performance against matrix interference. Overall, the label-free fluorescence aptasensors were developed and successfully validated in different foodstuffs, demonstrating a theoretical and practical basis for the study of aptamers against matrix interference.

[Effectiveness analysis of double EndoButton suture fixation Latarjet procedure for treatment of anterior shoulder dislocation with glenoid bone defect caused by military training injuries].

Objective: To investigate the effectiveness of double EndoButton suture fixation Latarjet procedure in the treatment of shoulder anterior dislocation with glenoid bone defect caused by military training injuries. Methods: The clinical data of 14 patients with anterior shoulder dislocation with glenoid bone defect due to military training injuries who met the selection criteria and admitted between August 2021 and December 2022 were retrospectively analyzed. All patients were male, the age ranged from 21 to 38 years, with an average of 26.8 years. The time from initial dislocation to operation was 6-15 months, with an average of 10.2 months. Anterior shoulder dislocation occurred 5-12 times, with an average of 8.2 times. All glenoid bone defects were more than 10%, including 5 cases of 10%-15%, 8 cases of 15%-20%, and 1 case of 24%. All patients were treated by double EndoButton suture fixation Latarjet procedure. The operation time and complications were recorded. The shoulder function and pain were evaluated by the American Association for Shoulder and Elbow Surgery (ASES) score, Rowe score, Instability Severity Index Score (ISIS), and visual analogue scale (VAS) score before and after operation. The range of motion of the shoulder was recorded, including forward flexion, 0° external rotation, and abduction 90° external rotation. The position, healing, and resorption of the bone mass were evaluated by three-dimensional CT of shoulder joint after operation. Results: All patients successfully completed the operation, and the operation time was 100-150 minutes, with an average of 119.7 minutes. There was no complications such as infection, vascular and nerve injury. All patients were followed up 12-20 months, with an average of 15.6 months. During the follow-up, 4 patients had bone mass separation, absorption, and recurrent anterior dislocation, and the shoulder joint fear test was positive. Imaging of the remaining patients showed that the bone mass healed well, no anterior dislocation recurrence occurred, and the healing time was 3-7 months (mean, 4.7 months). At last follow-up, the range of motion, ASES score, Rowe score, ISIS score, and VAS score of the patients significantly improved when compared with those before operation ( P<0.05). Conclusion: The effectiveness of double EndoButton suture fixation Latarjet procedure for the treatment of anterior shoulder dislocation with glenoid bone defect caused by military training injury is satisfactory.

Cochaperonin CPN20 negatively regulates abscisic acid signaling in Arabidopsis.

Previous study showed that the magnesium-protoporphyrin IX chelatase H subunit (CHLH/ABAR) positively regulates abscisic acid (ABA) signaling. Here, we investigated the functions of a CHLH/ABAR interaction protein, the chloroplast co-chaperonin 20 (CPN20) in ABA signaling in Arabidopsis thaliana. We showed that down-expression of the CPN20 gene increases, but overexpression of the CPN20 gene reduces, ABA sensitivity in the major ABA responses including ABA-induced seed germination inhibition, postgermination growth arrest, promotion of stomatal closure and inhibition of stomatal opening. Genetic evidence supports that CPN20 functions downstream or at the same node of CHLH/ABAR, but upstream of the WRKY40 transcription factor. The other CPN20 interaction partners CPN10 and CPN60 are not involved in ABA signaling. Our findings show that CPN20 functions negatively in the ABAR-WRKY40 coupled ABA signaling independently of its co-chaperonin role, and provide a new insight into the role of co-chaperones in the regulation of plant responses to environmental cues.

The Mg-chelatase H subunit of Arabidopsis antagonizes a group of WRKY transcription repressors to relieve ABA-responsive genes of inhibition.

The phytohormone abscisic acid (ABA) plays a vital role in plant development and response to environmental challenges, but the complex networks of ABA signaling pathways are poorly understood. We previously reported that a chloroplast protein, the magnesium-protoporphyrin IX chelatase H subunit (CHLH/ABAR), functions as a receptor for ABA in Arabidopsis thaliana. Here, we report that ABAR spans the chloroplast envelope and that the cytosolic C terminus of ABAR interacts with a group of WRKY transcription factors (WRKY40, WRKY18, and WRKY60) that function as negative regulators of ABA signaling in seed germination and postgermination growth. WRKY40, a central negative regulator, inhibits expression of ABA-responsive genes, such as ABI5. In response to a high level of ABA signal that recruits WRKY40 from the nucleus to the cytosol and promotes ABAR-WRKY40 interaction, ABAR relieves the ABI5 gene of inhibition by repressing WRKY40 expression. These findings describe a unique ABA signaling pathway from the early signaling events to downstream gene expression.

Roles of the different components of magnesium chelatase in abscisic acid signal transduction.

The H subunit of Mg-chelatase (CHLH) was shown to regulate abscisic acid (ABA) signaling and the I subunit (CHLI) was also reported to modulate ABA signaling in guard cells. However, it remains essentially unknown whether and how the Mg-chelatase-catalyzed Mg-protoporphyrin IX-production differs from ABA signaling. Using a newly-developed surface plasmon resonance system, we showed that ABA binds to CHLH, but not to the other Mg-chelatase components/subunits CHLI, CHLD (D subunit) and GUN4. A new rtl1 mutant allele of the CHLH gene in Arabidopsis thaliana showed ABA-insensitive phenotypes in both stomatal movement and seed germination. Upregulation of CHLI1 resulted in ABA hypersensitivity in seed germination, while downregulation of CHLI conferred ABA insensitivity in stomatal response in Arabidopsis. We showed that CHLH and CHLI, but not CHLD, regulate stomatal sensitivity to ABA in tobacco (Nicotiana benthamiana). The overexpression lines of the CHLD gene showed wild-type ABA sensitivity in Arabidopsis. Both the GUN4-RNA interference and overexpression lines of Arabidopsis showed wild-type phenotypes in the major ABA responses. These findings provide clear evidence that the Mg-chelatase-catalyzed Mg-ProtoIX production is distinct from ABA signaling, giving information to understand the mechanism by which the two cellular processes differs at the molecular level.

The Mg-chelatase H subunit is an abscisic acid receptor.

Abscisic acid (ABA) is a vital phytohormone that regulates mainly stomatal aperture and seed development, but ABA receptors involved in these processes have yet to be determined. We previously identified from broad bean an ABA-binding protein (ABAR) potentially involved in stomatal signalling, the gene for which encodes the H subunit of Mg-chelatase (CHLH), which is a key component in both chlorophyll biosynthesis and plastid-to-nucleus signalling. Here we show that Arabidopsis ABAR/CHLH specifically binds ABA, and mediates ABA signalling as a positive regulator in seed germination, post-germination growth and stomatal movement, showing that ABAR/CHLH is an ABA receptor. We show also that ABAR/CHLH is a ubiquitous protein expressed in both green and non-green tissues, indicating that it might be able to perceive the ABA signal at the whole-plant level.

Screening of Estrogenic-Disrupting Compounds in Dairy Products Based on the Estrogen Receptor Cocktail.

The residue of estrogenic-disrupting compounds (EDCs) that are secreted by cows, added as drugs, and present in the feed may exist in dairy products. A gold nanoparticles (AuNPs)-estrogen receptor (ER) cocktail colorimetric assay equipped with ER cocktail solid phase extraction (SPE) was established to screen EDCs. Nine EDCs with high, moderate, and low estrogenic activity were selected to be the representative targets. The recognition range of the colorimetric assay combined with the ER cocktail SPE was wider than that of a single ERα or ERß. The lowest detection limit of the established assay was about 10-9 mg·mL-1. The detection limits of estrone, bisphenol A, and bisphenol B were about one order of magnitude lower than the method based on a single ER. The recoveries of the spiked nine EDCs were between 80.0% and 110.0%, and daidzein was identified in the dairy product. The developed method has potential application prospects in food safety and environmental monitoring.

Salmonella typhimurium strip based on the photothermal effect and catalytic color overlap of PB@Au nanocomposite.

This work reports a sensitive and accurate multimode detection method to detect Salmonella typhimurium using inherent color, photothermal and catalytic properties of Prussian blue@gold nanoparticles (PB@Au). The inherent color of PB@Au can realize direct visual detection while the temperature increase (ΔT) of it can realize sensitive and quantitative photothermal detection. Moreover, catalytic coloration detection is applied to further amplify detection signal. The risk limit, prevention and control of Salmonella typhimurium can be more intuitively displayed through catalytic color overlap degree between PB@Au and catalytic product. The sensitivity of method is improved through photothermal and catalytic coloration detection (101 CFU·mL-1) compared with direct visual detection (102 CFU·mL-1). The multimode detection improves the accuracy of method, and exhibits good repeatability, acceptable selectivity and stability. This method is also successfully applied in real samples, displaying its good practical applicability.

A label-free electrochemical immunosensor for carbofuran detection based on a sol-gel entrapped antibody.

In this study, an anti-carbofuran monoclonal antibody (Ab) was immobilized on the surface of a glassy carbon electrode (GCE) using silica sol-gel (SiSG) technology. Thus, a sensitive, label-free electrochemical immunosensor for the direct determination of carbofuran was developed. The electrochemical performance of immunoreaction of antigen with the anti-carbofuran monoclonal antibody was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), in which phosphate buffer solution containing [Fe(CN)(6)](3-/4-) was used as the base solution for test. Because the complex formed by the immunoreaction hindered the diffusion of [Fe(CN)(6)](3-/4-) on the electrode surface, the redox peak current of the immunosensor in the CV obviously decreased with the increase of the carbofuran concentration. The pH of working solution, the concentration of Ab and the incubation time of carbofuran were studied to ensure the sensitivity and conductivity of the immunosensor. Under the optimal conditions, the linear range of the proposed immunosensor for the determination of carbofuran was from 1 ng/mL to 100 µg/mL and from 50 µg/mL to 200 µg/mL with a detection limit of 0.33 ng/mL (S/N = 3). The proposed immunosensor exhibited good high sensitivity and stability, and it was thus suitable for trace detection of carbofuran pesticide residues.

Anomalous dispersion observed in signal arrivals at a deep-sea floor receiver.

An anomalous dispersion, e.g., when low frequencies arrive earlier whereas the high frequencies arrive later, was observed in the signal arrivals recorded by a single deep-sea bottom-mounted vector sensor. Numerical simulations and modal analyses, based on a three-layer range-independent model, are applied to interpret the anomalous dispersion. Results indicate that the arrival with anomalous dispersion corresponds to trapped modes in the low sound speed sediment and can be observed when both the source and receiver are deployed near the seafloor. Furthermore, the cutoff frequencies, dispersion characteristics, and energy distributions of trapped modes are also performed in this paper.

Overview of Rapid Detection Methods for Salmonella in Foods: Progress and Challenges.

Salmonella contamination in food production and processing is a serious threat to consumer health. More and more rapid detection methods have been proposed to compensate for the inefficiency of traditional bacterial cultures to suppress the high prevalence of Salmonella more efficiently. The contamination of Salmonella in foods can be identified by recognition elements and screened using rapid detection methods with different measurable signals (optical, electrical, etc.). Therefore, the different signal transduction mechanisms and Salmonella recognition elements are the key of the sensitivity, accuracy and specificity for the rapid detection methods. In this review, the bioreceptors for Salmonella were firstly summarized and described, then the current promising Salmonella rapid detection methods in foodstuffs with different signal transduction were objectively summarized and evaluated. Moreover, the challenges faced by these methods in practical monitoring and the development prospect were also emphasized to shed light on a new perspective for the Salmonella rapid detection methods applications.

A portable immune-thermometer assay based on the photothermal effect of graphene oxides for the rapid detection of Salmonella typhimurium.

Previously reported photothermal strip test methods generally used a membrane as the antibody carrier and a thermal imaging camera or sensor as detector. To further simplify the detection device, a modified mercury head of the glass thermometer can act as the antibody carrier. Meanwhile, the temperature variation signal (ΔT) generated by the photothermal effect of labeled nanomaterials can be detected by the thermometer directly. Thus, the antibody carrier and detector can be integrated on a portable and cheap thermometer, which greatly simplified the device and detection steps of the photothermal method. The excellent photothermal effect of graphene oxides was used to improve the detection sensitivity. The main parameters of the performance of immune-thermometer assay were optimized and the Salmonella typhimurium was chosen as the representative target. Under the optimized conditions, the ΔT and the different number of Salmonella typhimurium were plotted to establish the standard curve. The detection limit was estimated to be 103 CFU·mL-1. The entire detection operation was consistently finished in 15 min. Overall, the proposed immune-thermometer exhibited good precision, selectivity and acceptable stability. The immune-thermometer assay was also successfully implemented and validated in different foodstuffs, which showed that it can be used as a novel and promising technique for rapid, simple and on-site screening of hazards in food, biological, clinical or environmental samples.