Search

To address the limitations of low node utilization and inadequate adaptability in complex environments encountered by Rapidly-exploring Random Tree (RRT) algorithms during the expansion phase, this study presents an enhanced path planning algorithm—AODA-PF-RRT* (Adaptive Obstacle Density Adjustment-PF-RRT*). The proposed algorithm implements a random extension strategy for nodes that fail collision detection, thereby improving node efficiency. Furthermore, it dynamically partitions the area surrounding sampling points and calculates local obstacle density in real time. By leveraging this density information, the algorithm flexibly adjusts both the number of expansion points and the dichotomy threshold, significantly enhancing its responsiveness to environmental changes. We rigorously demonstrate the algorithm's probabilistic completeness and asymptotic optimality. Simulation and benchmarking results demonstrate that the AODA-PF-RRT* algorithm not only generates smooth and high-quality paths compared to existing algorithms but also maintains low computational costs in complex environments, showcasing exceptional stability and robustness. [ABSTRACT FROM AUTHOR]

With the acceleration of urbanization and the growing demand for traffic safety, developing intelligent systems capable of accurately recognizing and tracking pedestrian trajectories at night or under low-light conditions has become a research focus in the field of transportation. This study aims to improve the accuracy and real-time performance of nighttime pedestrian-detection and -tracking. A method that integrates the multi-object detection algorithm YOLOP with the multi-object tracking algorithm DeepSORT is proposed. The improved YOLOP algorithm incorporates the C2f-faster structure in the Backbone and Neck sections, enhancing feature extraction capabilities. Additionally, a BiFormer attention mechanism is introduced to focus on the recognition of small-area features, the CARAFE module is added to improve shallow feature fusion, and the DyHead dynamic target-detection head is employed for comprehensive fusion. In terms of tracking, the ShuffleNetV2 lightweight module is integrated to reduce model parameters and network complexity. Experimental results demonstrate that the proposed FBCD-YOLOP model improves lane detection accuracy by 5.1%, increases the IoU metric by 0.8%, and enhances detection speed by 25 FPS compared to the baseline model. The accuracy of nighttime pedestrian-detection reached 89.6%, representing improvements of 1.3%, 0.9%, and 3.8% over the single-task YOLO v5, multi-task TDL-YOLO, and the original YOLOP models, respectively. These enhancements significantly improve the model's detection performance in complex nighttime environments. The enhanced DeepSORT algorithm achieved an MOTA of 86.3% and an MOTP of 84.9%, with ID switch occurrences reduced to 5. Compared to the ByteTrack and StrongSORT algorithms, MOTA improved by 2.9% and 0.4%, respectively. Additionally, network parameters were reduced by 63.6%, significantly enhancing the real-time performance of nighttime pedestrian-detection and -tracking, making it highly suitable for deployment on intelligent edge computing surveillance platforms. [ABSTRACT FROM AUTHOR]

The Ni60 alloy cladding layer with different La2O3 content was prepared by laser cladding technology on 35CrMoV surface. The phase composition, element distribution, micro-structure and tribological properties of the coating with different addition of La2O3 were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Microscopic Vickers hardness tester, MicroXAM-800 optical surface photometer and friction testing machine. The results show that the main phases of the cladding layer are (Ni, Fe), CrB, CrMn, Cr7C3 and Cr23C6. The diffraction peak shifted to the left in XRD with the addition of La2O3, which indicates that there is a certain lattice distortion in the cladding phase. The microstructure of the cladding layer is refined, the friction coefficient and the depth of wear trace are decreased to varying degrees, and the wear resistance of the cladding layer is greatly improved. The results show that the addition of 1.6%La2O3 can effectively refine grain, inhibit the formation of cracks and pores, and improve the wear performance of the cladding layer. [ABSTRACT FROM AUTHOR]

In the present work, a WC particle-reinforced CoCrFeMnNi high-entropy alloy (HEA) was fabricated by laser melting deposition (LMDed). The LMDed CoCrFeMnNi high-entropy alloy (CoCrFeMnNi) composite is primarily comprised of a face-centered cubic (FCC) crystal structure. However, in the case of CoCrFeMnNi with 2.5 wt.% WC, it exhibits a combination of an FCC matrix and a ceramic phase known as M23C6. The corrosion behavior of CoCrFeMnNi and CoCrFeMnNi with 2.5 wt.% WC particle in 0.5 M H2SO4 was comparatively investigated. Compared with CoCrFeMnNi, the passive film formed on the CoCrFeMnNi with 2.5 wt.% WC had a more stable and stronger protective property. The corrosion current density of the CoCrFeMnNi with 2.5 wt.% WC dropped by 149.1% compared to that of the CoCrFeMnNi, indicating that the CoCrFeMnNi with 2.5 wt.% WC had better corrosion resistance than that of the CoCrFeMnNi. [ABSTRACT FROM AUTHOR]

Ni-WC composite coatings on 35CrMoV alloy surface were successfully prepared by mechanical vibration field-assisted laser cladding technology. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to study the microstructure of the composite coatings without vibration and at different vibration frequencies; the phase composition of the cladding layer was studied by X-ray diffraction (XRD); and an energy dispersive spectrometer (EDS) was used for elemental plane scanning analysis. The grain growth trend under different convection directions was simulated. The wear resistance and mechanical properties of the composite coating were analyzed by friction and wear testing machine, three-dimensional surface profiler, and microhardness tester. The vibration field generated by the self-improved shaking table device is used to assist laser cladding. The effect of mechanical vibration on the quality of the cladding layer was studied. The results show that compared with the coating without mechanical vibration, an appropriate increase in vibration frequency contributes to the refinement of the grains. The original coarse dendrite structure becomes a fine needle-like structure, and the fine grain size gradually decreases. The application of vibration can improve the effect of grain refinement. The vibration makes the grain size distribution more uniform and the microhardness fluctuation of the cladding layer decreases. The experimental results show that mechanical vibration can improve the microstructure uniformity of the coating by selecting suitable vibration parameters. The average friction coefficient and wear width are reduced, and the microhardness is also increased. [ABSTRACT FROM AUTHOR]

Diffusion-weighted imaging (DWI) has been proven to be effective in detecting breast malignancies and has been widely implemented for breast imaging. However, the exact association between certain DWI biomarkers and well-known prognostic factors remains to be fully elucidated. By studying the association between the apparent diffusion coefficient (ADC) and prognostic factors, the present study aimed to explore the diagnostic value and prognostic potential of the ADC in breast lesions. The study included 539 female subjects with histopathologically confirmed breast lesions who underwent DWI of the breast tissue. The diagnoses comprised 307 subjects with malignant breast tumors and 232 with benign breast tumors. The maximum ADC and mean ADC (ADCmean) values of the breast lesions were calculated. For malignant tumors, the association between ADC and major prognostic factors, including histological grade, nuclear grade and lymph node status, as well as estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2) and proliferation marker protein Ki-67.(Ki-67) status, were evaluated. The ADCmean demonstrated the best diagnostic performance in distinguishing between malignant and benign lesions. With the optimum cut-off value at 1.30×10−3 mm2/sec, ADCmean had a sensitivity and specificity of 84.1 and 90.2%, respectively. In those patients with malignant breast lesions, a decreased ADC was associated with breast lesions with high nuclear and histological grades, and lymph node-positive, ER-negative, PR-negative and HER-2-negative status, and Ki-67 ≥14%. In conclusion, the ADC is a useful imaging biomarker for differentiating between benign and malignant breast tumors. The marked association between the ADC and prognostic factors also demonstrated its value in evaluating the malignancy of breast lesions. [ABSTRACT FROM AUTHOR]

Ureteropelvic junction obstruction (UPJO) is a common congenital malformation of the urinary system, which is mostly unilateral and frequently combined with hydronephrosis and kidney stones. The incidence of kidney stones is ~20%, which markedly increases the difficulty and risk of surgery. The present report describes a rare case of bilateral UPJO combined with bilateral renal stones. Laparoscopy and ureteroscopy one-stage surgery was performed creatively. CT urography demonstrated that the hydronephrosis was markedly reduced after the surgery, the ureteropelvic junction was patent without stone residue and the surgical outcome was ideal. [ABSTRACT FROM AUTHOR]

Titanium for additive manufacturing presents a challenge in the control of costs in the fabrication of products with expanding applications compared with cast titanium. In this study, hydrogenated–dehydrogenated (HDH) titanium powder with a low cost was employed to produce spherical Ti powder using the radiofrequency plasma (RF) technique. The spherical Ti powder was used as the raw material for laser directed energy deposition (LDED) to produce commercially pure titanium (CP-Ti). Microstructural analyses of the powder revealed that RF treatment, not only optimized the shape of the titanium powder, but also benefited in the removal of the residual hydride phase of the powder. Furthermore, the LDED-HDH-RF-produced samples showed an excellent combination of tensile strength and tensile ductility compared to the cast and the LDED-HDH-produced samples. Such an enhancement in the mechanical properties was attributed to the refinement of the α grain size and the dense microstructure. The present work provides an approach for LDED-produced CP-Ti to address the economic and mechanical properties of the materials, while also providing insights into the expanding application of HDH titanium powder. [ABSTRACT FROM AUTHOR]

• Parallel microgrooves are fabricated on the bottom of five parallel microchannels (W=200 µm, H=250 µm, L=10 mm) to enhance the boiling heat transfer without sacrificing pressure drop. • A highly desirable periodic rewetting mechanism was observed to substantially delay CHF conditions and enhance heat transfer rates. • Compared to plain-wall microchannels, HTC is enhanced up to ~50% at a mass flux of 303 kg/m2s due to the sustainable thin film evaporation. Moreover, CHF is substantially enhanced by ~155% at a mass flux of 389 kg/m2s due to the rapid and periodic rewetting enabled by these decorated microgrooves. • The enhancement in nucleate boiling was investigated under heat pulse with heating period of 0.5 s. Flow boiling in microchannels is one of the most desirable cooling solutions for high power electronics. However, it is challenging to promote the flow boiling performance, particularly critical heat flux (CHF), due to their unfavorable liquid rewetting. Inlet restrictors (IRs) have been successfully used to manage two-phase instabilities in flow boiling in microchannels. However, IRs would result in extremely high pressure drop. In this study, without using IRs, parallel microgrooves (W=50 µm, H=250 µm, L=10 mm) are fabricated on the bottom surface of five parallel microchannels (W=200 µm, H=250 µm, L=10 mm) to effectively manage two-phase flow instabilities without sacrificing pressure drop. Our visualization study shows that these microgrooves can enable rewetting at highhigh frequencies up to 151 Hz and enhance thin film evaporation with the highest thin film ratio of 0.65. A highly desirable periodic rewetting mechanism can substantially delay CHF conditions and enhance heat transfer rates. Flow boiling in the present microchannel configuration has been systematically characterized with mass flux ranging from 100 kg/m2s to 600 kg/m2s. Compared to plain-wall microchannels, flow boiling heat transfer coefficient (HTC) is enhanced up to ~72% at a mass flux of 210 kg/m2s due to the sustainable thin film evaporation. Moreover, CHF is substantially enhanced by ~155% at a mass flux of 389 kg/m2s due to the rapid and periodic rewetting enabled by these decorated microgrooves. We also observed that the enhancement of HTC fades when mass flux exceeds 346 kg/m2s due to flooding. [ABSTRACT FROM AUTHOR]

MiR-16-5p, a member of the miR-16 family, has been reported to be abnormal expression in tumor tissues and blood of tumor patients, and also downregulated in most cancer cell lines. Aberrant expression of miR-16-5p promotes tumor cell proliferation, invasion, metastasis, angiogenesis, and can also affect the treatment sensitivity, such as radiotherapy and chemotherapy. Generally, miR-16-5p plays an anti-tumor role and these diverse functions of miR-16-5p in tumors collectively indicate that miR-16-5p may become an attractive target for novel anticancer therapies and a powerful diagnostic and prognostic biomarker for early tumor detection and population risk screening. Herein we review the role and utilization of miR-16-5p in malignant tumor in detail. [Display omitted] • MiR-16-5p is abnormally expressed in tumor bulk, blood and cell lines. • MiR-16-5p plays an anti-cancer role in most malignant solid tumors. • MiR-16-5p is a powerful diagnostic and prognostic biomarker for malignant solid tumors. [ABSTRACT FROM AUTHOR]

• Alternating Nucleate Boiling of water is examined in this study. • The HTC and CHF are significantly enhanced on the present design. • The enhancements of HTC and CHF are without escalating pressure drop. • HTC and CHF can be substantially enhanced up to 111% and 24%. • A CHF value of 810 W/cm2 is achieved at a moderate mass flux of 430 kg/m2∙s. Flow boiling in parallel and isolated microchannels has been extensively studied. In this study, five parallel microchannels (W = 200 µm, H = 250 µm, L = 10 mm) are interconnected by 28 micro-slots (20 µm wide and 250 µm deep) starting from the outlet. These micro-slots serve as nucleation sites to greatly enhance nucleate boiling. More importantly, the alternating and enhanced nucleate boiling in neighboring microchannels can generate additional pressure drop during the bubble growth-departure cycle and hence enable highly desirable periodic rewetting inside channels, particularly near outlet regions. This new microchannel configuration can substantially enhance nucleate boiling during flow boiling processes. Coupling with the enhanced nucleate boiling and the induced thin film evaporation, heat transfer coefficient (HTC) in present microchannel configuration can be enhanced up to ~107.6% at mass flux 250 kg/m2∙s with a ~17% higher critical heat flux (CHF) compared to the plain-wall microchannels with inlet restrictors (IRs). In addition, we achieve a CHF value of 810 W/cm2 at a moderate mass flux of 430 kg/m2∙s. All these enhancements are realized without compromising two-phase pressure drop compared to plain wall microchannels with inlet restrictors (IRs). Two-phase flow instabilities in terms of temperature and pressure drop fluctuations are also significantly suppressed. [ABSTRACT FROM AUTHOR]

Introduction The problem of population aging is intensifying worldwide. Osteoporosis has become an important cause affecting the health status of older populations. However, the diagnosis of osteoporosis and people's understanding of it are seriously insufficient. We aim to develop a deep learning model to automatically measure bone mineral density (BMD) and improve the diagnostic rate of osteoporosis. Methods The images of 801 subjects with 2080 vertebral bodies who underwent abdominal paired computer tomography (CT) and quantitative computer tomography (QCT) scanning was retrived from June 2020 to January 2022. The BMD of T11-L4 vertebral bodies was measured by QCT. Developing a multi-stage deep learning-based model to simulate the segmentation of the vertebral body and predict BMD. The subjects were randomly divided into training dataset, validation dataset and test dataset. Analyze the fitting effect between the BMD measured by the model and the standard BMD by QCT. Accuracy, precision, recall and f1- score were used to analyze the diagnostic performance according to categorization criterion measured by QCT. Results 410 males (51.2%) and 391 females (48.8%) were included in this study. Among them, there were 154 (19.2%) males and 118 (14.7%) females aged 23-44; 182 (22.7%) males and 205 (25.6%) females aged 45-64; 74 (9.2%) males and 68 (8.5%) females aged 65-84. The number of vertebral bodies in the training dataset, the validation dataset, and the test dataset was 1433, 243, 404, respectively. In each dataset, the BMD of males and females decreases with age. There was a significant correlation between the BMD measured by the model and QCT, with the coefficient of determination (r2) 0.95-0.97. The diagnostic accuracy based on the model in the three datasets was 0.88, 0.91, and 0.91, respectively. Conclusion The proposed multi-stage deep learning-based model can achieve automatic measurement of vertebral BMD and performed well in the prediction of osteoporosis., (S. Karger AG, Basel.)

Background: Brown adipose tissue (BAT) is involved both in energy production and bone metabolism. The purpose of this study was to analyze the relationship between BAT and microarchitecture at cancellous and cortical bone using Kunming mice and the methods of 7T magnetic resonance imaging (MRI) combined with micro-CT., Methods: Twenty-four female Kunming mice were examined by 7T MRI and measured T2* relaxation time on the deep and superficial interscapular BAT (iBAT) and subcutaneous white adipose tissue (sWAT). Cancellous bone microarchitecture of the distal femur and cortical bone of the middle femur were examined by micro-CT. A paired t-test was used to analyze the differences in T2* values between iBAT and sWAT. The correlation between BAT T2* values and bone microstructure parameters were analyzed using Pearson's correlation., Results: T2* values of the deep and superficial iBAT (6.36±3.31 ms and 6.23±2.61 ms) were significantly shorter than those of sWAT (16.30±3.05 ms, t(deep) iBAT=-10.816), t(superficial) iBAT =-12.276, p<0.01). Deep iBAT T2* values were significantly and negatively correlated with bone volume, cancellous thickness, and bone thickness (Th) and trabecular thickness (Tb.Th) of the cancellous bone of femur. Deep iBAT T2* values were significantly and positively correlated with the structural model index of cancellous bone of femur. Deep iBAT T2* values were significantly and negatively correlated with bone mineral density of the cortical bone of femur., Conclusions: MRI can distinguish the two adipose tissues from each other. T2* values of BAT were lower than WAT on MRI. BAT related bone remodeling was more correlated with the microstructure of cancellous bone than that of cortical bone., (©The Author(s) 2022. Open Access. This article is licensed under a Creative Commons CC-BY International License.)