Line-Based 6-DoF Object Pose Estimation and Tracking With an Event Camera.

Pose estimation and tracking of objects is a fundamental application in 3D vision. Event cameras possess remarkable attributes such as high dynamic range, low latency, and resilience against motion blur, which enables them to address challenging high dynamic range scenes or high-speed motion. These features make event cameras an ideal complement over standard cameras for object pose estimation. In this work, we propose a line-based robust pose estimation and tracking method for planar or non-planar objects using an event camera. Firstly, we extract object lines directly from events, then provide an initial pose using a globally-optimal Branch-and-Bound approach, where 2D-3D line correspondences are not known in advance. Subsequently, we utilize event-line matching to establish correspondences between 2D events and 3D models. Furthermore, object poses are refined and continuously tracked by minimizing event-line distances. Events are assigned different weights based on these distances, employing robust estimation algorithms. To evaluate the precision of the proposed methods in object pose estimation and tracking, we have devised and established an event-based moving object dataset. Compared against state-of-the-art methods, the robustness and accuracy of our methods have been validated both on synthetic experiments and the proposed dataset. The source code is available at https://github.com/Zibin6/LOPET.

Event-based depth estimation with dense occlusion.

Occlusions pose a significant challenge to depth estimation in various fields, including automatic driving, remote sensing observation, and video surveillance. In this Letter, we propose a novel, to the best of our knowledge, depth estimation method for dense occlusion to estimate the depth behind occlusions. We design a comprehensive procedure using an event camera that consists of two steps: rough estimation and precise estimation. In the rough estimation, we reconstruct two segments of the event stream to remove occlusions and subsequently employ a binocular intersection measurement to estimate the rough depth. In the precise estimation, we propose a criterion that the maximum total length of edges of reconstructed images corresponds to the actual depth and search for the precise depth around the rough depth. The experimental results demonstrate that our method is implemented with relative errors of depth estimation below 1.05%.

Motion measurements of explosive shock waves based on an event camera.

Shock wave measurement is vital in assessing explosive power and designing warheads. To obtain satisfactory observation data of explosive shock waves, it is preferable for optical sensors to possess high-dynamic range and high-time resolution capabilities. In this paper, the event camera is first employed to observe explosive shock waves, leveraging its high dynamic range and low latency. A comprehensive procedure is devised to measure the motion parameters of shock waves accurately. Firstly, the plane lines-based calibration method is proposed to compute the calibration parameters of the event camera, which utilizes the edge-sensitive characteristic of the event camera. Then, the fitted ellipse parameters of the shock wave are estimated based on the concise event data, which are gained by utilizing the characteristics of the event triggering and shock waves' morphology. Finally, the geometric relationship between the ellipse parameters and the radius of the shock wave is derived, and the motion parameters of the shock wave are estimated. To verify the performance of our method, we compare our measurement results in the TNT explosion test with the pressure sensor results and empirical formula prediction. The relative measurement error compared to pressure sensors is the lowest at 0.33% and the highest at 7.58%. The experimental results verify the rationality and effectiveness of our methods.

Interferometric-scale full-field vibration measurement by a combination of digital image correlation and laser vibrometer.

Digital Image Correlation (DIC) is a crucial noncontact full-field optical measurement method used in various fields. However, in practical applications, DIC is affected by systematic and random noises, leading to experimental resolutions lower than theoretical ones. In this study, we proposed a laser Doppler vibrometer guided DIC to perform vibration measurements. 3D-DIC obtains a sequence of out of displacement field initially. A three-dimensional frequency domain collaborative filtering (3D-FDCF) method that utilizes Laser Doppler vibrometer (LDV) single-point data to assist in processing of the displacement field sequence pixel-wise is adopted. The 3D-FDCF method combines lowpass filtering in the spatial frequency domain with LDV-guided bandpass filtering in the temporal frequency domain. The effectiveness of the 3D-FDCF method is demonstrated through a comparison among DIC data, the filtered DIC data, and continuously scanning LDV data. The experiment results demonstrate the 3D-FDCF method's capability in measuring vibration amplitudes of several hundred nanometers with the size of a test sample of about 100 mm × 100 mm, supporting the statement of interferometric scale full-field vibration measurement by DIC with the guidance of the LDV data.

Therapy management and outcome of acute hydrocephalus secondary to intraventricular hemorrhage in adults.

BACKGROUND: Intraventricular hemorrhage (IVH) refers to bleeding within the brain's ventricular system, and hydrocephalus is a life-threatening complication of IVH characterized by increased cerebrospinal fluid accumulation in the ventricles resulting in elevated intracranial pressure. IVH poses significant challenges for healthcare providers due to the complexity of the underlying pathophysiology and lack of standardized treatment guidelines. Herein, we performed a systematic review of the treatment strategies for hydrocephalus secondary to IVH. METHODS: This systematic review was prospectively registered with PROSPERO (CRD42023450786). The search was conducted in PubMed, Cochrane Library, and Web of Science on July 15, 2023. We included original studies containing valid information on therapy management and outcome of hydrocephalus secondary to primary, spontaneous, and subarachnoid or intracranial hemorrhage following IVH in adults that were published between 2000 and 2023. Glasgow Outcome Scale (GOS) or modified Ranking Scale (mRS) scores during follow-up were extracted as primary outcomes. The risk of bias was assessed using the Newcastle-Ottawa Scale for Cohort Studies or Cochrane Risk of Bias 2.0 Tool. RESULTS: Two hundred and seven patients from nine published papers, including two randomized controlled trials, were included in the analysis. The GOS was used in five studies, while the mRS was used in four. Seven interventions were applied, including craniotomy for removal of hematoma, endoscopic removal of hematoma with/without endoscopic third ventriculostomy (ETV), traditional external ventricular drainage (EVD), and various combinations of EVD, lumbar drainage (LD), and intraventricular fibrinolysis (IVF). Endoscopic removal of hematoma was performed in five of nine studies. Traditional EVD had no obvious benefit compared with new management strategies. Three different combinations of EVD, LD, and IVF demonstrated satisfactory outcomes, although more studies are required to confirm their reliability. Removal of hematoma through craniotomy generated reliable result. Generally, endoscopic removal of hematoma with ETV, removal of hematoma through craniotomy, EVD with IVF, and EVD with early continuous LD were useful. CONCLUSION: EVD is still crucial for the management of IVH and hydrocephalus. Despite a more reliable result from the removal of hematoma through craniotomy, a trend toward endoscopic approach was observed due to a less invasive profile.

Dietary Flavonoid Quercetin Supplement Promotes Antiviral Innate Responses Against Vesicular Stomatitis Virus Infection by Reshaping the Bacteriome and Host Metabolome in Mice.

SCOPE: Active ingredients in functional foods exhibit broad-spectrum antiviral activity. The objective of this study is to investigate the protective effect of quercetin derived from bee propolis, a natural product with antiviral activity and modulating effects on the gut microbiota, against vesicular stomatitis virus (VSV) infection. METHODS AND RESULTS: Through a cellular-based study, this study demonstrates that quercetin can modulate the activity of interferon-regulating factor 3 (IRF3). In vivo, it shows that quercetin protects mice from VSV infection by enhancing interferon production and inhibiting the production of proinflammatory cytokines. The study conducts 16S rRNA-based gut microbiota and nontargets metabolomics analyses to elucidate the mechanisms underlying quercetin-mediated bidirectional communication between the gut microbiome and host metabolome during viral infection. Quercetin not only ameliorates VSV-induced dysbiosis of the intestinal flora but also alters serum metabolites related to lipid metabolism. Cross-correlations between the gut bacteriome and the serum metabolome indicate that quercetin can modulate phosphatidylcholine (16:0/0:0) and 5-acetylamino-6-formylamino-3-methyluracil to prevent VSV infection. CONCLUSION: This study systematically elucidates the anti-VSV mechanism of quercetin through gut bacteriome and host metabolome assays, offering new insights into VSV treatment and revealing the mechanisms behind a novel disease management strategy using dietary flavonoid supplements.

Pro-endothelialization of nitinol alloy cardiovascular stents enhanced by the programmed assembly of exosomes and endothelial affinity peptide.

Stent implantation is one of the most effective methods for the treatment of atherosclerosis. Nitinol stent is a type of stent with good biocompatibility and relatively mature development; however, it cannot effectively achieve long-term anticoagulation and early endothelialization. In this study, nitinol surfaces with the programmed assembly of heparin, exosomes from endothelial cells, and endothelial affinity peptide (REDV) were fabricated through layer-by-layer assembly technology and click-chemistry, and then exosomes/REDV-modified nitinol interface (ACC-Exo-REDV) was prepared. ACC-Exo-REDV could promote the rapid proliferation and adhesion of endothelial cells and achieve anticoagulant function in the blood. Besides, ACC-Exo-REDV had excellent anti-inflammatory properties and played a positive role in the transformation of macrophage from the pro-inflammatory to anti-inflammatory phenotype. Ex vivo and in vivo experiments demonstrated the effectiveness of ACC-Exo-REDV in preventing thrombosis and hyperplasia formation. Hence, the programmed assembly of exosome interface could contribute to endothelialization and have potential application on the cardiovascular surface modification to prevent stent thrombosis and restenosis.

Analysis of emission characteristics associated with vessel activities states in port waters.

This study investigates AIS data from March 2019 to February 2020 in Shanghai Port waters. The ship activities of berthing, waiting, and ingress/egress are extracted in detail to elucidate the emission characteristics of ships in Shanghai Port, differentiating emissions patterns across various ship activity. The findings reveal that the top three pollutants within Shanghai Port are CO2, NOX, and SO2. Container ships have the highest emissions, followed by bulk carriers. Berthed container ships and oil tankers exhibit the highest emission. Waiting container ships emit the most, followed by oil tankers and bulk carriers. Among ships entering and leaving the port, low-speed navigation produces the most emissions, followed by maneuvering and steady-speed navigation. Emission hotspots include the Yangtze River Estuary Anchorage and the main navigation channel into and out of the port. This study offers robust data support for an in-depth understanding and evaluation of ship emission characteristics in Shanghai Port.

Efficacy and safety of odevixibat in patients with Alagille syndrome (ASSERT): a phase 3, double-blind, randomised, placebo-controlled trial.

BACKGROUND: In patients with Alagille syndrome, cholestasis-associated clinical features can include high serum bile acids and severe pruritus that can necessitate liver transplantation. We aimed to evaluate the efficacy and safety of the ileal bile acid transporter inhibitor odevixibat versus placebo in patients with Alagille syndrome. METHODS: The ASSERT study was a phase 3, double-blind, randomised, placebo-controlled trial that enrolled patients at 21 medical centres or hospitals in ten countries (Belgium, France, Germany, Italy, Malaysia, the Netherlands, Poland, Türkiye, the UK, and the USA). Eligible patients had a genetically confirmed diagnosis of Alagille syndrome, a history of significant pruritus, and elevated serum bile acids. Patients were randomly assigned (2:1) to receive oral odevixibat 120 µg/kg per day or placebo for 24 weeks (in a block size of six and stratified by age: <10 years and ≥10 years to <18 years) via a web-based system. Patients, clinicians, study staff, and people analysing the data were masked to treatment allocation. The primary efficacy endpoint was change in caregiver-reported scratching score (on the PRUCISION instrument; range 0-4) from baseline to weeks 21-24. The prespecified key secondary efficacy endpoint was change in serum bile acid concentration from baseline to the average of weeks 20 and 24. Outcomes were analysed in patients who received at least one dose of study drug (the full analysis set for efficacy outcomes and the safety analysis set for safety outcomes). This trial is registered on ClinicalTrials.gov (NCT04674761) and EudraCT (2020-004011-28), and is completed. FINDINGS: Between Feb 26, 2021, and Sept 9, 2022, 52 patients were randomly assigned to receive odevixibat (n=35) or placebo (n=17), all of whom were included in the analysis sets. The median age was 5·5 years (IQR 3·2 to 8·9). 27 (52%) of 52 patients were male and 25 (48%) were female. The mean scratching score was elevated at baseline in both groups (2·8 [SD 0·5] for odevixibat vs 3·0 [0·6] for placebo). Mean scratching scores at weeks 21-24 were 1·1 (0·9) for odevixibat and 2·2 (1·0) for placebo, representing a least-squares (LS) mean change of -1·7 (95% CI -2·0 to -1·3) for odevixibat and -0·8 (-1·3 to -0·3) for placebo, which was significantly greater for odevixibat than for placebo (difference in LS mean change from baseline -0·9 [95% CI -1·4 to -0·3]; p=0·0024). Odevixibat also resulted in significantly greater reductions in mean serum bile acids from baseline versus placebo (237 µmol/L [SD 115] with odevixibat vs 246 µmol/L [121] with placebo) to the average of weeks 20 and 24 (149 µmol/L [102] vs 271 µmol/L [167]; LS mean change -90 µmol/L [95% CI -133 to -48] with odevixibat vs 22 µmol/L [-35 to 80] with placebo; difference in LS mean change -113 µmol/L [95% CI -179 to -47]; p=0·0012). The most common treatment-emergent adverse events were diarrhoea (ten [29%] of 35 patients in the odevixibat group vs one [6%] of 17 in the placebo group) and pyrexia (eight [23%] vs four [24%]). Seven patients had serious treatment-emergent adverse events during the treatment period: five (14%) in the odevixibat group and two (12%) in the placebo group. No patients discontinued treatment and there were no deaths. INTERPRETATION: Odevixibat could be an efficacious non-surgical intervention to improve pruritus, reduce serum bile acids, and enhance the standard of care in patients with Alagille syndrome. Longer-term safety and efficacy data of odevixibat in this population are awaited from the ongoing, open-label ASSERT-EXT study. FUNDING: Albireo Pharma, an Ipsen company.

Improving energy efficiency: a highly efficient coaxial design for a laser ranging system with a splicing lens.

Light detection and ranging (LiDAR) systems have made significant contributions in different applications. The laser ranging (LR) system is one of the core components of LiDARs. However, existing coaxial LR systems suffer from low energy efficiency due to obstruction of the reflection mirror. In this study, we carefully design a laser transmitter and receiver subsystem and consequently propose a highly energy-efficient coaxial design for a time of light-based LR system, where a perforated mirror and splicing lens account for the promotion of energy efficiency. The small hole in the perforated mirror is located on the object focus of the focusing lens to ensure the laser beam will pass through the perforated mirror without obstructions. The ring-shape splicing lens, consisting of two parts, is used for laser collimation and laser reception simultaneously. Laboratory experiments proved that the proposed design eliminates the complex calibration process for noncoaxial LR systems while reaching a comparable energy efficiency, which is higher than 98%. We believe it is an economical yet efficient way to promote the energy efficiency of coaxial LR systems.

Optimizing the design of axial flow pump blades based on fluid characteristics.

Non-physiological blood flow conditions in axial blood pumps lead to some complications, including hemolysis, platelet activation, thrombosis, and embolism. The high speed of the axial blood pump destroys large amounts of erythrocytes, thereby causing hemolysis and thrombosis. Thus, this study aims to reduce the vortices and reflux in the flow field by optimizing the axial blood pump. The axial blood pump and arterial flow field were modeled by the finite element method. The blood was assumed to be incompressible, turbulent, and Newtonian. The SST k-ω turbulence model was used. The frozen rotor method was also used to calculate the snapshot of motion. Many vortices and reflux exist in the flow field of the blood pump without optimization. The improved flow field had almost no vortex and reflux, thereby reducing the exposure time of blood. The optimized blood pump had little influence on the pressure field and shear stress field. The optimized blood pump mainly reduced the vortex, reflux, and the risk of thrombosis in the flow field. The flow field characteristics of an axial blood pump were studied, and the results showed the risk of thrombosis and hemolysis in the blood pump. In accordance with the relationship between the blade shape and the flow field, the blade of the blood pump was optimized, reducing the vortex and reflux of the flow field, as well as the risk of thrombosis.

Image-registration-based solar meridian detection for accurate and robust polarization navigation.

Skylight polarization, inspired by the foraging behavior of insects, has been widely used for navigation for various platforms, such as robots, unmanned aerial vehicles, and others, owing to its stability and non-error-accumulation. Among the characteristics of skylight-polarized patterns, the angle of polarization (AOP) and the degree of polarization (DOP) are two of the most significant characteristics that provide abundant information regarding the position of the sun. In this study, we propose an accurate method for detecting the solar meridian for real-time bioinspired navigation through image registration. This method uses the AOP pattern to detect the solar meridian and eliminates the ambiguity between anti-solar meridian and solar meridian using the DOP pattern, resulting in an accurate heading of the observer. Simulation experiments demonstrated the superior performance of the proposed method compared to the alternative approaches. Field experiments demonstrate that the proposed method achieves real-time, robust, and accurate performance under different weather conditions with a root mean square error of 0.1° under a clear sky, 0.18° under an overcast sky with a thin layer of clouds, and 0.32° under an isolated thick cloud cover. Our findings suggest that the proposed method can be potentially used in skylight polarization for real-time and accurate navigation in GPS-denied environments.

Zabramski classification in predicting the occurrence of symptomatic intracerebral hemorrhage in sporadic cerebral cavernous malformations.

OBJECTIVE: The authors aimed to investigate the evolutionary characteristics of the Zabramski classification of cerebral cavernous malformations (CCMs) and the value of the Zabramski classification in predicting clinical outcome in patients with sporadic CCM. METHODS: This retrospective study consecutively included cases of sporadic CCM that had been untreated from January 2001 through December 2021. Baseline and follow-up patient information was recorded. The evolution of the Zabramski classification of a sporadic CCM was defined as the initial lesion type changing into another type for the first time on MRI follow-up. The primary outcome was the occurrence of a hemorrhage event, which was defined as a symptomatic event with radiological evidence of overt intracerebral hemorrhage. RESULTS: Among the 255 included cases, 55 (21.6%) were classified as type I CCM, 129 (50.6%) as type II CCM, and 71 (27.8%) as type III CCM, based on initial MRI. During a mean follow-up of 58.8 ± 33.6 months, 51 (20.0%) patients had lesion classification transformation, whereas 204 (80.0%) patients maintained their initial type. Among the 51 transformed lesions, 29 (56.9%) were type I, 11 (21.6%) were type II, and 11 (21.6%) were type III. Based on all follow-up imaging, of the initial 55 type I lesions, 26 (47.3%) remained type I and 27 (49.1%) regressed to type III because of hematoma absorption; 91.5% of type II and 84.5% of type III lesions maintained their initial type during MRI follow-up. The classification change rate of type I lesions was statistically significantly higher than those of type II and III lesions. After a total follow-up of 1157.7 patient-years, new clinical hemorrhage events occurred in 40 (15.7%) patients. The annual cumulative incidence rate for symptomatic hemorrhage in all patients was 3.4 (95% CI 2.5-4.7) per 100 person-years. Kaplan-Meier survival analysis showed that the annual cumulative incidence rate for symptomatic hemorrhage of type I CCM (15.3 per 100 patient-years) was significantly higher than those of type II (0.6 per 100 patient-years) and type III (2.3 per 100 patient-years). CONCLUSIONS: This study suggests that the Zabramski classification is helpful in estimating clinical outcome and can assist with surgical decision-making in patients with sporadic CCM.

A Sequential Dual Functional Supramolecular Hydrogel with Promoted Drug Release to Scavenge ROS and Stabilize HIF-1α for Myocardial Infarction Treatment.

Myocardial infarction (MI) has a characteristic inflammatory microenvironment due to the overproduction of reactive oxygen species (ROS) and causes the extraordinary deposition of collagen and thereby fibrosis. An on-demand adaptive drug releasing hydrogel is designed to modulate the inflammatory microenvironment and inhibit cardiac fibroblasts (CFs) proliferation post MI by scavenging the overproduced ROS and releasing 1,4-dihydrophenonthrolin-4-one-3-carboxylic acid (DPCA) to maintain the expression of hypoxia-inducible factor 1α (HIF-1α). DPCA is prefabricated to a prodrug linked with disulfide bond (DPCA-S-S-OH). The DPCA-S-S-OH and carboxylated calixarene (CSAC4A) are grafted onto the backbone of methacrylated hyaluronic acid (HAMA) to obtain HAMA-S-S-DPCA and HAMA-CA, respectively, which are further reacted to form a dual network hydrogel (R+ /DPCA(CA)) with covalent linking and host-guest interaction between DPCA and CSAC4A. The ROS-triggered hydrolysis of ester bond and subsequently sustaining release of DPCA from the cavity of CSAC4A jointly cause the constant expression of HIF-1α, which significantly restricts the CFs proliferation, leading to suppressed fibrosis and promoted heart repair.

Calibration method for monocular laser speckle projection system.

This paper proposes a novel calibration method for the monocular laser speckle projection system. By capturing images of a calibration board with speckles under different poses, projector's optical axis is fitted and utilized to calibrate the rotation between the camera and projector. The translation is solved in closed form subsequently and projector's virtual image is recovered via homography. After calibration, the system can be regarded and operated as a binocular stereo vision system with speckle pattern. The proposed method is efficient and convenient, without need of reference image or high-precision auxiliary equipment. Validated by experiments on Astra-s and Astra-pro, it presents significant improvement in depth-estimation compared to the traditional method.

Two large-exposure-ratio image fusion by improved morphological segmentation.

The fusion of two large-exposure-ratio images, especially in the rocket launch field, is a challenging task because of fast-moving objects and differential features from daily scenes. Based on the large-exposure-ratio images, we propose a principle of halo formation at the boundaries of over-exposed areas. To avoid the halos in the fusion images, an improved morphological segmentation (IMS) method is developed to segment the over-exposed regions and boundaries. The IMS method is inspired by the mountain topography and builds a bridge between the 3D patches and quadratic polynomial coefficients. An improved multiscale method with segmentation in high-exposed images is proposed. In the rocket launch observation experiment, we constructed a two-camera simultaneous imaging system to avoid the dynamic scenes. The result of our proposed fusion method could best preserve the details and colors of the flames in low-exposed images and has the best subjective observation. The objective matrices also demonstrate superior edge and contrast performances over mainstream methods.

Interim results from an ongoing, open-label, single-arm trial of odevixibat in progressive familial intrahepatic cholestasis.

Background & Aims: PEDFIC 2, an ongoing, open-label, 72-week study, evaluates odevixibat, an ileal bile acid transporter inhibitor, in patients with progressive familial intrahepatic cholestasis. Methods: PEDFIC 2 enrolled and dosed 69 patients across two cohorts; all received odevixibat 120 µg/kg per day. Cohort 1 comprised children from PEDFIC 1, and cohort 2 comprised new patients (any age). We report data through 15 July 2020, with Week 24 of PEDFIC 2 the main time point analysed. This represents up to 48 weeks of cumulative exposure for patients treated with odevixibat from the 24-week PEDFIC 1 study (cohort 1A) and up to 24 weeks of treatment for those who initiated odevixibat in PEDFIC 2 (patients who received placebo in PEDFIC 1 [cohort 1B] or cohort 2 patients). Primary endpoints for this prespecified interim analysis were change from baseline to Weeks 22-24 in serum bile acids (sBAs) and proportion of positive pruritus assessments (≥1-point drop from PEDFIC 2 baseline in pruritus on a 0-4 scale or score ≤1) over the 24-week period. Safety monitoring included evaluating treatment-emergent adverse events (TEAEs). Results: In cohort 1A, mean change from PEDFIC 1 baseline to Weeks 22-24 of PEDFIC 2 in sBAs was -201 µmol/L (p <0.0001). For cohort 1B and cohort 2, mean changes from odevixibat initiation to weeks 22-24 in sBAs were -144 and -104 µmol/L, respectively. The proportion of positive pruritus assessments in the first 24-week period of PEDFIC 2 was 33%, 56%, and 62% in cohorts 1A, 1B, and 2, respectively. Most TEAEs were mild or moderate. No drug-related serious TEAEs occurred. Conclusions: Odevixibat in patients with progressive familial intrahepatic cholestasis was generally well tolerated and associated with sustained reductions in sBAs and pruritus. Clinical Trials Registration: This study is registered at ClinicalTrials.gov (NCT03659916). Impact and Implications: Disrupted bile flow is a hallmark feature of patients with progressive familial intrahepatic cholestasis and can result in build-up of bile constituents in the liver with spill over into the bloodstream; other effects that patients can experience include extremely itchy skin, and because not enough bile reaches the gut, patients can have problems digesting food, which may lead to poor growth. Odevixibat is an orally administered medication that shunts bile acids away from the liver. The current study, called PEDFIC 2, suggested that odevixibat can improve the problematic signs and symptoms of progressive familial intrahepatic cholestasis and was generally safe for patients.

An Efficient Method for Laser Welding Depth Determination Using Optical Coherence Tomography.

Online monitoring of laser welding depth is increasingly important, with the growing demand for the precise welding depth in the field of power battery manufacturing for new energy vehicles. The indirect methods of welding depth measurement based on optical radiation, visual image and acoustic signals in the process zone have low accuracy in the continuous monitoring. Optical coherence tomography (OCT) provides a direct welding depth measurement during laser welding and shows high achievable accuracy in continuous monitoring. Statistical evaluation approach accurately extracts the welding depth from OCT data but suffers from complexity in noise removal. In this paper, an efficient method coupled DBSCAN (Density-Based Spatial Clustering of Application with Noise) and percentile filter for laser welding depth determination was proposed. The noise of the OCT data were viewed as outliers and detected by DBSCAN. After eliminating the noise, the percentile filter was used to extract the welding depth. By comparing the welding depth determined by this approach and the actual weld depth of longitudinal cross section, an average error of less than 5% was obtained. The precise laser welding depth can be efficiently achieved by the method.

Systematic evaluation of the toxicological effects of deltamethrin exposure in zebrafish larvae.

Deltamethrin (DM) is a widely used pesticide and has been generally detected in aquatic systems. To systematically investigate the toxic effects, zebrafish embryos were treated with various concentrations of DM for 120 h. The LC50 was determined to be 102 µg L-1. Lethal concentrations of DM induced severe morphological defects in the surviving individuals. Under non-lethal concentrations, DM suppressed the development of neurons in the larvae, which was associated with the reduction in locomotor activity. DM exposure induced cardiovascular toxicity, including suppressed growth of blood vessels and enhanced heart rates. DM also disrupted the development of bones in the larvae. Moreover, liver degeneration, apoptosis and oxidative stress were observed in the larvae treated with DM. Correspondingly, the transcriptional levels of the genes related to the toxic effects were altered by DM. In conclusion, the results obtained in this study provided evidence that DM showed multiple toxic effects on aquatic organisms.