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For studying the effect of nitriding treatment on the microstructure and wear properties of HVOF sprayed Al1-xCoCrFeNiTix(x＝0，0.125，0.250) high-entropy alloy coatings，the HVOF technology was employed to prepare Al1-xCoCrFeNiTix(x＝0，0.125，0.250) highentropy alloy coating on 35CrMo steel substrate，which were further nitrided.The effects of nitriding treatment on the microstructure and wear properties of Al1-xCoCrFeNiTix(x＝0，0.125，0.250) high-entropy alloy coating prepared by HVOF were studied via characterization methods such as SEM，XRD，3D white light interferometer and EDS.Results showed that the high-entropy alloy coating of Al1-xCoCrFeNiTix(x＝0，0.125，0.250) after nitriding treatment had a dense microstructure with a typical thermal spray coating-like structure.The coating thickness was about 300～350 μm，the nitriding layer thickness was about 10 μm，and the nitriding layer phase structure was FCC phase and AlN，CrN and other nitriding phases.Meanwhile，the microhardness of the nitriding layer was 981 HV2N(x＝0)，1 090 HV2N(x＝0.125) and 1 194 HV2N(x＝0.250)，respectively，which was significantly improved compared with the microhardness of 479 HV2N(x＝0)，506 HV2N(x＝0.125) and 548 HV2N(x＝0.250) of the unnitrided high-entropy alloy coating.With the increase of Ti content，the wear resistance of the nitriding layer increased，and Al0.750CoCrFeNiTi0.250nitriding layer possessed the best wear resistance [(2.17×10-6mm3/(N·m)].Besides，the wear failure mechanism of Al1-xCoCrFeNiTix(x＝0，0.125，0.250) nitriding layer was mainly abrasive wear，oxidation wear and adhesive wear.

Plasma dynamics are essential in high-power electron beam diodes, as they influence the current density and can even cause gap closure because of fast expansion velocity during operation. In this study, the formation and expansion of the cathode plasma in a high-power planar diode has been investigated by particle-in-cell simulations. The results indicate that the expansion velocity of the cathode plasma in the planar diode is ∼2.5 cm/μs operating with a 340 kV peak voltage and 1.5 kA current, which possesses a maximum pressure of 1 Torr pressure and a gas desorption rate of 38 molecules per electron. Moreover, the enhanced emission on the edge causes a faster growth rate of the gas pressure and formation of plasma, which possesses a higher plasma density than other regions. A higher gas desorption rate and total amount of outgoing gas can cause a larger velocity of plasma expansion, and the expansion velocity is proportional to the logarithm of the rising speed of the diode voltage, while the amplitude of diode voltage did not show a clear correlation with plasma velocity. Finally, a combined dependence of the plasma velocity on the gas desorption rate, total gas volume, rising speed of the diode voltage, and diode voltage is concluded. This work provides new insights into the dynamics of cathode plasma in high-power diodes and may be helpful for engineering design. [ABSTRACT FROM AUTHOR]

Frequency‐sweeping laser sources play a critical role in the accurate 3D mapping of frequency‐modulated continuous‐wave (FMCW) LiDAR systems, whose chirp linearity greatly impacts the measurement precision. Although various pre‐distortion algorithms have been proposed to reduce chirp nonlinearity, these open‐loop methods can rapidly suppress the chirp nonlinearity but they are susceptible to environmental variations and often exhibit subpar performance in long‐range detection scenarios. In contrast, the electro–optical phase‐locked loop (EO‐PLL) serves as a real‐time linearizing solution for FMCW LiDAR, enabling high‐precision, high‐resolution, and long‐distance measurement capabilities. In this study, a III/V‐Si3N4 hybrid‐integrated external cavity laser (ECL) is used to generate an FMCW signal over a large wavelength tuning range of 68 nm. The maximum output optical power is 15.8 mW, and the intrinsic linewidth is 0.9 kHz. By modulating the phase shifter, an FMCW signal with a chirp bandwidth of 0.7 GHz is generated at a repetition rate of 1 kHz. The pre‐distortion algorithm is combined with the gain‐tunable EO‐PLL system to suppress the chirp nonlinearity and frequency noise across multiple wavelengths, leading to a remarkable improvement in range precision from 202 to 4.2 cm when targeting a distance of 200 m. [ABSTRACT FROM AUTHOR]

Due to the inability to restore the original performance, a significant portion of retired mechanical products is often replaced with new ones and discarded or recycled as low-value materials. This practice leads to energy waste and a decline in their residual value. The generalized growth remanufacturing model (GGRM) presents opportunities to enhance the residual value of retired products and parts. It achieves this by incorporating a broader range of growth modes compared to traditional restorative remanufacturing approaches. The selection of the growth mode is a crucial step to achieve GGRM. However, there is a limited number of growth mode selection methods that are specifically suitable for GGRM. The capacity and efficiency of the method are also significant factors to consider. Therefore, we propose a growth mode selection method based on association rule mining. This method consists of three main steps: Firstly, the ReliefF method is used to select the core failure characteristics of retired parts. Secondly, a genetic algorithm (GA) is employed to identify the association between core failure characteristics, repair technology, and maximum recoverability. Finally, based on the maximum recoverability, the appropriate growth mode is selected for each retired part. We conduct a case study on retired automobile universal transmission, and the results demonstrate the feasibility, efficiency, and accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

Cancer-associated fibroblasts (CAFs) are considered one of the most critical stromal cells that interact with pancreatic ductal adenocarcinoma (PDAC) and promote tumor growth, metastasis, and treatment resistance. Previous studies illustrated macroautophagy/autophagy contributes to CAF activation during tumor progression. Here in our study, we found that autophagy deficiency in CAFs impedes CAF activation by inhibiting proline biosynthesis and collagen production. Furthermore, we uncovered that autophagy promotes proline biosynthesis through mitophagy-mediated regulation of NADK2 (NAD kinase 2, mitochondrial), an enzyme responsible for production of mitochondrial NADP(H). Using an orthotopic mouse model of PDAC, we found that inhibiting mitophagy by targeting PRKN (parkin RBR E3 ubiquitin protein ligase) in the stroma reduced tumor weight. Thus, inhibition of CAFs mitophagy might be an attractive strategy for stroma-focused anti-cancer intervention. Abbreviations: ACTA2/α-SMA: actin alpha 2, smooth muscle, aorta; ACTB/β-actin: actin, beta; ALDH18A1/P5CS: aldehyde dehydrogenase 18 family, member A1; ATG3: autophagy related 3; ATG5: autophagy related 5; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CAFs:cancer-associated fibroblasts; COL1A1: collagen, type I, alpha 1; DES: desmin; ECM: extracellular matrix; FABP4: fatty acid binding protein 4, adipocyte; FAP/FAPα: fibroblast activation protein; IHC: immunohistochemical staining; LAMP1: lysosomal-associated membrane protein 1; NADK2: NAD kinase 2, mitochondrial; PC1: pro-collagen 1; PDAC: pancreatic ductal adenocarcinoma; PDGFR: platelet derived growth factor receptor; PDPN: podoplanin; PRKN: parkin RBR E3 ubiquitin protein ligase; PSCs: pancreatic stellate cells; VIM: vimentin; WT: wild-type [ABSTRACT FROM AUTHOR]

We report a wavelength widely-tunable hybrid integrated external cavity laser (ECL) with synchronous tuning to achieve a large frequency chirp bandwidth and high chirp linearity. Si3N4 Vernier microring resonators (MRRs) in the ECL function as an optical bandpass filter to offer strong wavelength selectivity and fast frequency tunability. The wavelength tuning range is 56 nm, the maximum output optical power is 22.5 mW, the minimum intrinsic linewidth is 2.9 kHz, and the static frequency sweep bandwidth is 56 GHz. A frequency-modulated continuous-wave (FMCW) signal is generated under synchronous modulation with a chirp bandwidth of 7.68 GHz at a 1 kHz repetition rate, much larger than that produced by modulating the phase shifter or the Vernier filter alone. A chirp linearization method based on a non-uniform sampling algorithm and an iterative learning algorithm is employed to reduce the chirp nonlinearity to 1.02×10-7, allowing for a detection resolution of 2.47 cm. [ABSTRACT FROM AUTHOR]

Background: Cell survival or death is one of the key scientific issues of inflammatory response. To regulate cell death during the occurrence and development of periodontitis, various forms of programmed cell death, such as pyroptosis, ferroptosis, necroptosis, and apoptosis, have been proposed. It has been found that ferroptosis characterized by iron-dependent lipid peroxidation is involved in cancer, degenerative brain diseases and inflammatory diseases. Furthermore, NCOA4 is considered one of ferroptosis-related genes (FRGs) contributing to butyrate-induced cell death in the periodontitis. This research aims to analyze the expression of FRGs in periodontitis tissues and to explore the relationship between ferroptosis and periodontitis. Method: Genes associated with periodontitis were retrieved from two Gene Expression Omnibus datasets. Then, we normalized microarray data and removed the batch effect using the R software. We used R to convert the mRNA expression data and collected the expression of FRGs. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), transcription factor (TF) and protein-protein interaction (PPI) network analyses were used. In addition, we constructed a receiver operating characteristic curve and obtained relative mRNA expression verified by quantitative reverse-transcription polymerase chain reaction (PCR). Results: Eight and 10 FRGs related to periodontitis were upregulated and downregulated, respectively. GO analysis showed that FRGs were enriched in the regulation of glutathione biosynthetic, glutamate homeostasis, and endoplasmic reticulum-nucleus signaling pathway. The top TFs included CEBPB, JUND, ATF2. Based on the PPI network analysis, FRGs were mainly linked to the negative regulation of IRE1-mediated unfolded protein response, regulation of type IIa hypersensitivity, and regulation of apoptotic cell clearance. The expression levels of NCOA4, SLC1A5 and HSPB1 using PCR were significantly different between normal gingival samples and periodontitis samples. Furthermore, the diagnostic value of FRGs for periodontitis were "Good". Conclusions: We found significant associations between FRGs and periodontitis. The present study not only provides a new possible pathomechanism for the occurrence of periodontitis but also offers a new direction for the diagnosis and treatment of periodontitis. [ABSTRACT FROM AUTHOR]

Chip-scale lasers with a wide tunable range and a narrow linewidth have rich applications in optical communications, sensing, and light detection and ranging systems. External cavity lasers (ECLs) have the advantage of a wide tuning range and a narrow linewidth compared with their counterparts such as distributed feedback lasers and distributed Bragg reflector lasers because the passive filter separated from the gain section can be widely tuned and the low-loss external cavity extends the photon lifetime. However, so far, the tuning range achieved by the chip-scale ECLs is in the range of 80–120 nm, smaller than that of the bulk free-space ECL (typically >160 nm). The bottleneck in reaching an ultrabroad tuning range for chip-scale ECLs lies in the unsuppressed side modes of the external cavity. Here, we demonstrate a hybrid-integrated ECL consisting of a broadband III–V reflective semiconductor optical amplifier and a low-loss Si3N4 wavelength-selective reflector. A record 172-nm lasing wavelength tuning range together with a more than 40 dB side-mode suppression ratio is achieved beyond the free spectral range of the Vernier ring filter due to the enhanced lasing mode selection from a tunable Sagnac loop reflector. The Si3N4 platform enables a low-loss external cavity, facilitating laser linewidth reduction below 4 kHz over the full tuning range. The on-chip output power reaches 26.7 mW at a wavelength of 1550 nm. [ABSTRACT FROM AUTHOR]

Silicon nitride (Si3N4) has a higher nonlinear threshold compared to silicon, which reduces the effect of two-photon absorption. However, the low thermo-optic coefficient and the reduced refractive index contrast of thin Si3N4 waveguides lead to a low thermal tuning speed and low thermal efficiency. This paper demonstrates a widely tunable III-V/Si3N4 hybrid-integrated external cavity laser with a relatively faster switching time. The Si3N4 external feedback circuit is based on 800-nm-thick Si3N4 waveguides with an optical confinement factor of 87%. It allows the reduction of the oxide under-cladding layer thickness to 4 μm and the oxide upper-cladding layer to 1.7 μm without additional loss. The switching time between two non-adjacent lasing wavelengths is 60.7 μs. The maximum output power is 34 mW under 500 mA injection current. The side mode suppression ratio is more than 70 dB over the tuning range of 58.5 nm. The laser intrinsic linewidth is 2.5 kHz. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate a method to generate a low-chirp ultra-wideband pulse (UWB) signal based on a silicon single-drive push-pull segmented Mach-Zehnder modulator (SMZM). The concept is analyzed theoretically and demonstrated experimentally. We get positive monocycle pulses with different relative time delays between the two driving signals. The center frequency and fractional bandwidth of the generated positive monocycle pulse is 5.97 GHz and 161% with a relative time delay of 56 ps. By changing the operating point of the SMZM, we can get negative monocycle pulses. We modulate the UWB signals with on-off keying and pulse position formats by properly coding the driving signal. As far as we know, this is the first time to realize low-chirp UWB signals using only one silicon modulator. The successful generation of UWB signals poses a significant step in realizing a compact low-cost and low-chirp UWB generator on the silicon photonics platform. [ABSTRACT FROM AUTHOR]

Rising global temperatures have resulted in urban heat waves in recent years, endangering residents' health and even their lives. As a result, accurate outdoor thermal comfort prediction is critical. The goal of this research is to develop highly accurate and interpretable machine learning models of outdoor thermal comfort. We created a summer outdoor thermal comfort dataset for cold regions using microclimate parameter measurements and questionnaires, and divided it into two datasets: without and with shading. The prediction performance of nine machine learning models was compared, as well as their prediction performance following Bayesian optimization. Finally, the SHAP model was used to explain the important features of the best machine learning models and their impact on thermal comfort. The results show that after partitioning the dataset by shading, the accuracy of the best machine learning prediction models for Thermal sensation vote (TSV), Thermal acceptable vote (TA), and Thermal comfort vote (TCV) in the unshaded space improves by 9.2%, 9.31%, and 6.16%, respectively, while the prediction accuracy in the shaded space remains basically unchanged. Extreme gradient boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), and categorical boosting (CatBoost) outperform other methods. After Bayesian optimization (BO), the machine learning models' TSV, TA, and TCV prediction accuracies improved by 6.83%, 4.05%, and 2.55%, respectively. CatBoost model with Bayesian optimization (CatBoost + BO) was the best model in most cases. TSV, TA, and TCV predictions were heavily influenced by microclimate parameters, with mean radiant temperature being the most important in unshaded spaces and air temperature being critical in shaded spaces. Furthermore, age, body mass index, and emotional state all had a significant impact on TA and TCV. This research will contribute to improving the quality of life of urban residents by providing a scientific foundation for the design and planning of urban open space. [Display omitted] • Outdoor thermal comfort models considered shade were built using nine ML algorithms. • The optimal model is Categorical Boosting combined with Bayesian optimization. • SHAP used to explain feature importance and positive/negative effects of models. [ABSTRACT FROM AUTHOR]

We demonstrate novel phase-coded microwave signal generation based on a two-segment single-drive push–pull silicon Mach–Zehnder modulator. The coding signal and the microwave frequency are each applied to one of the separate segments. The phase-coded microwave signal is generated by properly setting the working point of the modulator. The precise π phase shift is determined by the sign of the coding signal. Both theoretical analysis and experimental demonstration are performed to verify the concept. The modulator successfully generates a 10-GHz (20-GHz) phase-coded microwave signal with a 5-Gb/s (10-Gb/s) coding data rate and the measured pulse compression ratio is 133.0 (156.8). [ABSTRACT FROM AUTHOR]

Autophagy is an essential degradation and recycling process that maintains cellular homeostasis during stress or nutrient deprivation. However, certain types of tumors such as pancreatic cancers can circumvent autophagy inhibition to sustain growth. The mechanism that autophagy-deficient pancreatic ductal adenocarcinoma (PDAC) uses to grow under nutrient deprivation is poorly understood. Our data show that nutrient deprivation in PDAC results in UDP-glucose dehydrogenase (UGDH) degradation, which is dependent on autophagic cargo receptor sequestosome 1 (p62). Moreover, we demonstrate that accumulated UGDH is indispensable for autophagy-deficient PDAC cells proliferation by promoting hyaluronic acid (HA) synthesis upon energy deprivation. Using an orthotopic mouse model of PDAC, we find that inhibition of HA synthesis by targeting UGDH in PDAC reduces tumor weight. Thus, the combined inhibition of HA and autophagy might be an attractive strategy for PDAC treatment. [Display omitted] • UGDH is degraded by autophagic process dependent on p62 • Autophagy-deficient PDAC upregulates UGDH to promote hyaluronic acid synthesis • Hyaluronic acid maintains autophagy-deficient PDAC proliferation under nutrient starvation Fan et al. report that UGDH is degraded by p62-mediated autophagy, and it accumulates in autophagy-deficient PDAC. UGDH increases hyaluronic acid (HA) synthesis to sustain proliferation of autophagy-deficient PDAC. The combined inhibition of UGDH/HA with autophagy results in reduction of PDAC growth. [ABSTRACT FROM AUTHOR]

The local regions of complex gyration class mechanical parts are largely different, which results in the problem that their surface images are partially clear. This problem directly affects the effectiveness of vision methods on detecting surface defects. To tackle this problem, a large depth-of-field (DoF) surface image fusion method is proposed to obtain a full-focus image of complex mechanical parts, such as gyration class mechanical parts. We design an image acquisition platform based on the characteristics of gyration class parts to acquire their surface images accurately and clearly. We then propose a feature detection-based image registration method, by which the registered image can represent the surface information of the part completely and accurately. Additionally, we adopt a convolutional neural network-based image fusion method to achieve a fused large DoF surface image. Experimental studies were conducted to evaluate the performance of the deep-learning-based methods. The experimental results show that the proposed method can completely and clearly fuse the large DoF surface images of complex gyration class mechanical parts. The quality of the fused images has a significant improvement, and the proposed method is significantly more efficient than traditional fusion methods and other deep-learning methods. [ABSTRACT FROM AUTHOR]

Radiant heating systems typically created a non-uniform thermal environment. The effect of radiant asymmetry on human thermal comfort was the main consideration in its application. However, previous studies did not emphasize the method of supplying fresh air and its impact on the asymmetric thermal environment. In this study, flow field distribution in a radiant heating room with diffuse ceiling ventilation system which had different porous ceiling opening rates was studied by numerical simulations. Meanwhile, subjective experiments were conducted to evaluate the influence on human thermal comfort. The results revealed that under different porous ceiling opening rates, non-uniform opening on the porous ceiling could optimize the indoor asymmetric thermal environment and reduce local draft discomfort. Furthermore, the neutral level in the room could be maintained at the same height by adjusting ceiling opening rates. The method of supplying fresh air into the radiant heating room had a certain impact on the asymmetric thermal environment. This paper served as a reference for the future design of the radiant system combined with a fresh air system. • DCV aided fresh air supply together with sidewall radiant asymmetric heating • Non-uniform distribution of buoyancy driven airflow • Neutral level control by DCV with non-uniform intensity [ABSTRACT FROM AUTHOR]

With the development of urbanization, the development of deep underground spaces has become increasingly important. The purpose of this research is to study how the combined effects of thermal and acoustic environments affect psychological and physiological stress of workers in deep undergrounds spaces. A randomized crossover chamber study with 16 subjects was carried out in this study. Participants were exposed to two different temperatures (30 and 34 °C), two different relative humidity levels (65 and 85%), and three different noise levels (55, 70 and 85 dBA). The experimental protocol included subjective thermal sensation, emotion, heart rate variability, skin temperature and cognitive performance tests. Results showed that temperature and relative humidity affected the change of emotion via their influence on thermal responses. In deep underground spaces, participants were always in a state of tension. The effect of temperature on low to high frequency ratio (LF/HF) was more pronounced at high noise levels. Low relative humidity could compensate for the discomfort caused by high temperatures. In general, temperature had the greatest influence, and the combined effect was significantly greater than the individual effect on workers' psychological and physiological stresses. • Combined effects of thermal and acoustic environments in deep underground spaces. • Using emotion and heart rate variability to explore to subjects' psychological and physiological stress. • Temperature and relative humidity will indirectly affect emotion changes. • The combined effects of temperature, relative humidity and noise are greater than the individual effect. [ABSTRACT FROM AUTHOR]

The application of stratified ventilation systems for winter heating brings out the doubt of draught issues on the lower part of body. The purpose of this study is to quantify the thermal sensation and air movement acceptability of occupants in an occupied space with the stratified convective–heating systems. Twenty subjects participated in eighteen trials and they were blinded to test conditions. Three air temperatures of 20.5, 21.5 and 23.0 °C and three local air speeds of 0.4, 0.6 and 0.8 m/s are chosen as the examined parameters in the warm air lake. Two shoe types of low–cut and high–top being considered for providing different protection on ankles were also used. Local and overall thermal sensation, thermal comfort and acceptability, air movement acceptability, the preference on thermal environment and air movement were collected. Perceived indoor air quality and dry eye symptoms were also acquired. Results demonstrated that subjects were sensitive to local air movement at both calves and ankles rather than the ankles only. Low air temperature (<23.0 °C) and high air speed (>0.4 m/s) in warm air lake may cause 20–65% of subjects to complain about the unacceptable air movement. High–top shoes could increase the air movement acceptability on ankles by 15% but little effects on calves were discovered. Only 7% of the subjects reported eye dryness in all tested conditions and almost all subjects could accept the indoor air quality. This work may help improve the understanding of draught sensation on lower body parts in an occupied space with the stratified convective–heating system. • Winter draught sensation assessment under attachment ventilation with relayed fans were studied. • The recommended air temperature in air lake should be higher than 23 °C and the air speed should be less than 0.6 m/s. • High–top shoes can provide a maximum improvement on air movement acceptability by 15% from unacceptable to acceptable. [ABSTRACT FROM AUTHOR]

• FAM20C phosphorylates regulatory proteins involved in bone development. • A novel Osx-Cre; FAM20Cflox/flox knockout (oKO) mouse model is established. • oKO has lower bone mineralization, along with greater hypertrophic cartilage. • oKO has up-regulation of osteoclast differentiation genes Sirpb1a-c and Mapk13. • Osteogenesis-related genes Osx, Alp, Ocn, Mepe, and Col2 are downregulated in oKO. Family with sequence similarity 20 member C (FAM20C) is a Golgi casein kinase that phosphorylates extracellularly-secreted regulatory proteins involved in bone development and mineralization, but its specific role in bone development is still largely unknown. In this study, to examine the specific mechanisms that FAM20C influences bone development, we cross-bred Osx-Cre with FAM20Cflox/flox mice to establish a Osx-Cre; FAM20Cflox/flox knockout (oKO) mouse model; FAM20C was KO in pre-osteoblasts. oKO development was examined at 1–10 weeks, in which compared to control FAM20Cflox/flox, they had lower body weights and bone tissue mineralization. Furthermore, oKO had lower bone volume fractions, thickness, and trabecular numbers, along with higher degrees of trabecular separation. These mice also had decreased femoral metaphyseal cartilage proliferation layer, along with thickened hypertrophic layer and increased apoptotic cell counts. Transcriptomic analysis found that differentially-expressed genes in oKO were concentrated in the osteoclast differentiation pathway, in line with increased osteoclast presence. Additionally, up-regulation of osteoclast-related, and down-regulation of osteogenesis-related genes, were identified, in which the most up-regulated genes were signal regulatory protein β-1 family (Sirpb1a-c) and mitogen-activated protein kinase 13. Overall, FAM20C KO in pre-osteoblasts leads to abnormal long bone development, likely due to subsequent up-regulation of osteoclast differentiation-associated genes. [ABSTRACT FROM AUTHOR]