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Abstract Objective To investigate the effect of bone cement on the vertebral body and biomechanical properties in percutaneous cement discoplasty (PCD) for degenerative lumbar disc disease. Methods Three-dimensional reconstruction of L2 ~ L3 vertebral bodies was performed in a healthy volunteer, and the corresponding finite element model of the spine was established. Biomechanical analysis was performed on the changes in stress distribution in different groups of models by applying quantitative loads. Results Models with percutaneous discoplasty (PCD) showed improved stability under various stress conditions, and intervertebral foraminal heights were superior to models without discoplasty. Conclusion Cement discoplasty can improve the stability of the vertebral body to a certain extent and restore a certain height of the intervertebral foramen, which has a good development prospect and potential.

BackgroundIntervertebral Disc Degeneration (IDD) is a major cause of lower back pain and a significant global health issue. However, the specific mechanisms of IDD remain unclear. This study aims to identify key genes and pathways associated with IDD using bioinformatics and machine learning algorithms.MethodsGene expression profiles, including those from 35 LDH patients and 43 healthy volunteers, were downloaded from the GEO database (GSE124272, GSE150408, GSE23130, GSE153761). After merging four microarray datasets, differentially expressed genes (DEGs) were selected for GO and KEGG pathway enrichment analysis. Weighted Gene Co-expression Network Analysis (WGCNA) was then applied to the merged dataset to identify relevant modules and intersect with DEGs to discover candidate genes with diagnostic value. A LASSO model was established to select appropriate genes, and ROC curves were drawn to elucidate the diagnostic value of genetic markers. A Protein-Protein Interaction (PPI) network was constructed and visualized to determine central genes, followed by external validation using qRT-PCR.ResultsDifferential analysis of the preprocessed dataset identified 244 genes, including 183 upregulated and 61 downregulated genes. WGCNA analysis revealed the most relevant module intersecting with DEGs, yielding 9 candidate genes. The lasso-cox method was used for regression analysis, ultimately identifying 6 genes: ASPH, CDC42EP3, FOSL2, IL1R1, NFKBIZ, TCF7L2. A Protein-Protein Interaction (PPI) network created with GENEMANIA identified IL1R1 and TCF7L2 as central genes.ConclusionOur study shows that IL1R1 and TCF7L2 are the core genes of IDD, offering new insights into the pathogenesis and therapeutic development of IDD.

Investigating the flow performance of Francis turbines from model to prototype is a complex but essential process for ensuring reliable and efficient turbine operation in hydropower plants. It ensures that Francis turbine designs operate efficiently under various operating conditions, extending from laboratory reduced-scale models to full-scale prototype installations. In this investigation, a Francis turbine model was tested under different operating conditions, and its properties were measured, including torque, hydraulic efficiency, power output, cavitation coefficient, rotational speed, flow rate, and pressure pulsations. The results of the Francis turbine model test indicate that it achieved the maximum torque with the designed discharge and designed head. The cavitation coefficient consistently remained higher than the critical cavitation coefficient. The initial cavitation bubbles were observed at 50% partial load but disappeared at full load. Pressure pulsations under different operating conditions showed the maximum peak-to-peak amplitude appearing at the turbine inlet domain and the minimum amplitude occurring at the draft tube elbow. A hill chart shows that the model’s best efficiency was 93.66%, and the estimated best efficiency of the prototype was 95.03% at the design head. The conclusions and methodology of this study can be generalized to other similar hydraulic turbines, especially prototype Francis turbines that lack experimental results.

Sediment erosion of hydraulic turbines is a significant challenge in hydropower plants in mountainous regions like the European Alps, the Andes, and the Himalayan region. The erosive wear of Pelton runner buckets is influenced by a variety of factors, including the size, hardness, and concentration of silt particles; the velocity of the flow and impingement angle of the jet; the properties of the base material; and the operating hours of the turbine. This research aims to identify the locations most susceptible to erosion and to elucidate the mechanisms of erosion propagation in two distinct designs of Pelton runner buckets. The Pelton runner buckets were subjected to static condition tests with particle sizes of 500 microns and a concentration of 14,000 mg/L. The buckets were coated with four layers of paint, sequentially applied in red, yellow, green, and blue. The two Pelton buckets, D1 and D2, were evaluated for their erosion resistance properties. D2 demonstrated superior erosion resistance, attributed to its geometrical features and material composition, lower erosion rates, less material loss, and improved surface integrity compared with D1. This difference is primarily attributed to factors such as the splitter’s thickness, the jet’s impact angle, the velocity at which particles strike, and the concentration of sand. D2 exhibits a great performance in terms of erosion resistance among the two designs. This study reveals that the angle of jet impingement influences erosion progression and material loss, which is important to consider during a Pelton turbine’s design and operating conditions.

The shaft system, transferring the kinetic energy of water flow into electrical energy, is the most critical component in hydropower plants. Installation deviations of the shaft system for a giant hydro-generator unit can have significant impacts on its dynamic characteristics and overall performance. In this investigation, a three-dimensional geometry of the shaft system of an operating hydro-generator unit prototype with a rated power of 1 GW is established. Then, the calculation model of the shaft system is generated accordingly with tetrahedral and hexahedral elements. By applying different boundary conditions, the finite-element method is used to analyze the influences of installation deviations, including shaft radial misalignment and angular misalignment, on the dynamic characteristics of the shaft system. The calculation results reveal that the installation deviations change the natural frequencies, critical speeds, and mode shapes of the shaft system to a certain degree. The natural frequencies of the backward precession motion with installation deviations are reduced by 23% and 38% for the rated speed and the maximum runaway speed. Furthermore, for the forward precession motion, they increased by 30% and 48%, respectively. The critical speeds for the shaft system with radial and angular deviations are 3.2% and 3% larger than the critical speed of the shaft system without any mounting deviations. The radial and angular installation deviations below the maximum permissible values will not result in the structural performance degradation of the 1 GW hydro-generator shaft system. The conclusion drawn in this research can be used as a valuable reference for installing other rotating machinery.

Abstract Background Adelphocoris suturalis (Hemiptera: Miridae) is a notorious agricultural pest, which causes serious economic losses to a diverse range of agricultural crops around the world. The poor understanding of its genomic characteristics has seriously hindered the establishment of sustainable and environment-friendly agricultural pest management through biotechnology and biological insecticides. Results Here, we report a chromosome-level assembled genome of A. suturalis by integrating Illumina short reads, PacBio, 10x Chromium, and Hi-C mapping technologies. The resulting 1.29 Gb assembly contains twelve chromosomal pseudomolecules with an N50 of 1.4 and 120.6 Mb for the contigs and scaffolds, respectively, and carries 20,010 protein-coding genes. The considerable size of the A. suturalis genome is predominantly attributed to a high amount of retrotransposons, especially long interspersed nuclear elements (LINEs). Transcriptomic and phylogenetic analyses suggest that A. suturalis-specific candidate effectors, and expansion and expression of gene families associated with omnivory, insecticide resistance and reproductive characteristics, such as digestion, detoxification, chemosensory receptors and long-distance migration likely contribute to its strong environmental adaptability and ability to damage crops. Additionally, 19 highly credible effector candidates were identified and transiently overexpressed in Nicotiana benthamiana for functional assays and potential targeting for insect resistance genetic engineering. Conclusions The high-quality genome of A. suturalis provides an important genomic landscape for further investigations into the mechanisms of omnivory, insecticide resistance and survival adaptation, and for the development of integrated management strategies.

Pump–turbine units with high heads are subjected to strong pressure pulsations from the unsteady transient flow in fluid channels, which can produce severe vibrations and high stresses on the pump–turbine structural components. Therefore, reducing transient flow-induced stresses on prototype reversible pump–turbine units is an important measure for ensuring their safe and efficient operation. A high-head prototype reversible pump–turbine with a rated head of 440 m was used to investigate the transient flow characteristics and the flow-induced-stresses in this study. First, the flow passages of the pump–turbine unit and the structure of the reversible pump–turbine runner were constructed with CAD tools. Next, CFD simulations at the full load were performed to investigate the pressure pulsation characteristics of the pump turbine in both the time domain and the frequency domain. After this, the pressure files calculated by the CFD were exported and applied to a finite element model of the pump–turbine runner to calculate the transient flow-induced dynamic stresses. The results show that the pressure pulsations in the flow passage are closely related to the rotational speed, the guide vane number, and the runner blade number of the pump–turbine unit. The maximum flow-induced stresses on the pump–turbine runner at the full load were below 2 MPa and lower than the allowable value, which reveals that the designs of the pump–turbine runner and the flow passage are acceptable. The conclusions can be used as a reference to evaluate the design of high-head pump–turbines units. The approaches used to carry out the transient flow-induced stress calculations can be applied not only to pump–turbines units but also to other types of fluid turbomachinery such as pumps, turbines, fans, compressors, turbochargers, etc.

This paper presents an automatic optimization system for the heat source layout of multi-chip modules, referred to as IOS. The system aims to optimize the heat source layout of multi-chip modules through the integration of multiple software tools. The IOS utilizes an optimization algorithm, WINDOW DOS, and other methods to achieve this goal. Initially, two optimization strategies are introduced which are utilized in conjunction with the Non-dominated Sorting Genetic Algorithm-II(NSGA-II). Subsequently, a simplified thermal model of the multi-chip module is applied to the IOS. The automatic optimization module is then used to optimize the heat source layout. In the end, we simulated and analyzed the application results. The simulation analysis reveals that when the temperature extreme value index is optimized, the PCB board’s transient temperature range falls within [343.14 K, 344.09 K]. Similarly, when the temperature homogeneity index is optimized, the PCB board’s transient temperature range falls within [343.39 K, 344.21 K]. Comparing these results with the experience layout, the temperature difference is reduced by 76.36% and 79.60%, respectively. The optimization results demonstrate that the IOS has a significant impact, offering remarkable optimization effects, low cost, high efficiency, and a more uniform temperature distribution. These findings indicate that the IOS holds promising potential for applications and provides value in optimizing the heat source layout of multi-chip modules.

In order to reduce the influence of temperature deformation of large-size body-mounted radiators on the observation accuracy of space station telescopes and adapt to launch vibration loads, this paper proposes a floating combination stress release mechanism. Firstly, based on the dimensions, operating conditions, and stress directions of the radiator, an “orthogonal + parallel” layout of the radiator stress release mechanism is designed. To verify whether the layout design complies with the fully constrained theory, the layout design model is simplified into a four-point model, including one fixed support, two line-degree-of-freedom release mechanisms, and one plane-degree-of-freedom release mechanism. Degree-of-freedom analysis is conducted, and the statically determinate support goal is successfully achieved. Then, through the layout design of the stress release mechanism, specific modeling designs are carried out for the fixed support, line-degree-of-freedom release mechanisms, and plane-degree-of-freedom release mechanism using three-dimensional modeling software. Finally, the feasibility of the design scheme is verified through finite element simulation and mechanical testing. The results show that under sine and random vibrations, the maximum response amplification factor is 4.2, which meets the design requirement of being less than five. The maximum stress is 192 MPa, which is lower than the material’s yield limit. Under the application of an 80 °C temperature difference, the displacement response value of the radiator is 3.28 mm. This value falls within the allowable movement range of the stress release mechanism and meets the design criteria.

Tb3+-activated LTA zeolite-derived boro-aluminosilicate glass samples with a composition of xTb2O3-68(Na2O-Al2O3-SiO2)–32B2O3 (x = 0.2, 1.0 and 10 extra wt%) were prepared using the melt-quenching method. The emission spectra recorded upon ultraviolet (UV) excitation with two different wavelengths of 193 and 378 nm showed blue light (5D3 to 7FJ=6,5,4 and 5D4 to 7F6 transitions of Tb3+) and green light (5D4 to 7F5 transition of Tb3+) emissions with comparable intensities up to a Tb3+ concentration of 10 extra wt%. Of note, the mean decay times of the green luminescence of the glass samples were relatively fast (

Objective: To investigate whether mineralized collagen modified polymethyl methacrylate (MC-PMMA) bone cement impacts the implanted vertebral body and adjacent segments and the feasibility of biomechanical properties compared with common bone cement in the treatment of osteoporotic vertebral compression fractures (OVCF).Methods: A healthy volunteer was selected to perform a three-dimensional reconstruction of the T11-L1 vertebral body to establish the corresponding finite element model of the spine, and the changes in the stress distribution of different types of cement were biomechanically analyzed in groups by applying quantitative loads.Results: The stress distribution of the T11-L1 vertebral body was similar between the two bone types of cement under various stress conditions.Conclusion: Mineralized collagen modified bone cement had the advantages of promoting bone regeneration, good biocompatibility, good transformability, and coupling, and had support strength not inferior to common PMMA bone cement, indicating it has good development prospects and potential.

Curcumenol, an effective ingredient of Wenyujin, has been reported that exerted its antitumor potential in a few cancer types. However, the effect and molecular mechanism of curcumenol in lung cancer are largely unknown. Here, we found that curcumenol induced cell death and suppressed cell proliferation in lung cancer cells. Next, we demonstrated that ferroptosis was the predominant method that contributed to curcumenol-induced cell death of lung cancer in vitro and vivo for the first time. Subsequently, using RNA sequencing, we found that the long non-coding RNA H19 (lncRNA H19) was significantly downregulated in lung cancer cells treated with curcumenol, when compared to untreated controls. Overexpression of lncRNA H19 eliminated the anticancer effect of curcumenol, while lncRNA H19 knockdown promoted ferroptosis induced by curcumenol treatment. Mechanistically, we showed that lncRNA H19 functioned as a competing endogenous RNA to bind to miR-19b-3p, thereby enhanced the transcription activity of its endogenous target, ferritin heavy chain 1 (FTH1), a marker of ferroptosis. In conclusion, our data show that the natural product curcumenol exerted its antitumor effects on lung cancer by triggering ferroptosis, and the lncRNA H19/miR-19b-3p/FTH1 axis plays an essential role in curcumenol-induced ferroptotic cell death. Therefore, our findings will hopefully provide a valuable drug for treating lung cancer patients.

During the operation of the water transportation pipelines in the upstream of the Yellow River, varying degrees of sand deposition often occur under a low flow rate. Taking into account the effect of different pipe inclinations, pipe diameters, and inlet sand content, the Eulerian–Eulerian two-phase model was applied in the numerical simulation of sediment-laden flow in a V-inclined pipe. The results indicate that there is a significant difference between a V-inclined pipe and horizontal pipe affected by gravity. Compared with the downward inclined pipe, sand deposition is evident in the upward inclined pipe. The high-velocity region moves upward and the asymmetry of the cross-sectional velocity increases. As the pipe diameter increases, the interaction between sand and the wall as well as the degree of turbulence decrease, so that the distribution of sand volume concentration across the cross section will be more uniform. Under different inlet sand content, the lowest point of the pipe experiences the most sand deposition, with sand volume concentration and velocity distribution across the cross-sections becoming uneven as inlet sand content increases. The location of the maximum liquid velocity varies from section to section. When the inlet sand content increases from 0.42% to 5%, the liquid velocity of the pipe cross-section no longer satisfies the rule of high velocity for middle and low velocity near the wall.

This paper focuses on a 1000 MW Francis turbine and conducts a numerical analysis of the entire flow passage using computational fluid dynamics (CFD) under steady-state conditions. Building upon prior research, we further investigate the impact of an uneven gap distribution caused by radial co-directional installation deviations of 0.1 mm, 0.3 mm, 0.5 mm, 1.5 mm, and 2.5 mm on the pressures and radial forces at various locations of the turbine, including the upper crown chamber, the vaneless zone, and the bottom ring chamber, all under steady-state rated operating conditions. By examining the maximum and minimum pressure values under different conditions, we determined that different pressure reading methods should be applied to distinct surfaces. Additionally, we derived the patterns illustrating how different components are affected by radial installation deviations. The significance of this study lies in its comprehensive exploration of the influence of radial installation deviations on the performance of a Francis turbine, particularly under steady-state rated conditions. Through numerical analysis, we elucidated the specific effects of various deviation magnitudes on the pressures and radial forces at different turbine locations. These findings provide valuable insights for the optimization of turbine design and operation. The novelty of this work stems from its in-depth investigation of radial co-directional installation deviations and the extensive results obtained through numerical simulations. These results hold significant implications for improving turbine performance and reliability, surpassing previous efforts in the literature.

This study proposes a random forest algorithm to evaluate water poverty. It shows how the machine learning technique can be used to classify the degree of water poverty into five levels: very severe, severe, moderate, mild, and very mild. The strengths of the proposed random forest method include a high classification accuracy, good operational efficiency, and the ability to handle high-dimensional datasets. The success of the proposed method is empirically illustrated through a case study in Gansu, Northwest China. The analysis shows that from 2000 to 2017, the severity of water poverty in the study area declined. In 2000, most municipalities were classified as level 1 (very severe) or level 2 (severe). In 2017, level 1 water poverty disappeared, with most municipalities classified in as level 3 (moderate) and level 4 (mild). Spatially, there is a significant difference between the water poverty levels of the western, central, and eastern parts of Gansu, and the eastern part is affected by serious water poverty problems. HIGHLIGHTS This study proposes a random forest algorithm to classify the level of water poverty.; The proposed method is empirically illustrated through a case study in Gansu, Northwest China.; The strengths of the proposed method include a high classification accuracy, good operational efficiency, and the ability to handle high-dimensional datasets.;

Accumulating evidence suggests that chronic inflammation may play a critical role in various malignancies, including bladder cancer. This hypothesis stems in part from inflammatory cells observed in the urethral microenvironment. Chronic inflammation may drive neoplastic transformation and the progression of bladder cancer by activating a series of inflammatory molecules and signals. Recently, it has been shown that the microbiome also plays an important role in the development and progression of bladder cancer, which can be mediated through the stimulation of chronic inflammation. In effect, the urinary microbiome can play a role in establishing the inflammatory urethral microenvironment that may facilitate the development and progression of bladder cancer. In other words, chronic inflammation caused by the urinary microbiome may promote the initiation and progression of bladder cancer. Here, we provide a detailed and comprehensive account of the link between chronic inflammation, the microbiome and bladder cancer. Finally, we highlight that targeting the urinary microbiome might enable the development of strategies for bladder cancer prevention and personalized treatment.

Background: Recent studies demonstrate that N6-methyladenosine (m6A) methylation plays a crucial role in colorectal cancer (CRC). Therefore, we conducted a comprehensive analysis to assess the m6A modification patterns and identify m6A-modified genes in patients with CRC recurrence.Methods: The m6A modification patterns were comprehensively evaluated by the NMF algorithm based on the levels of 27 m6A regulators, and tumor microenvironment (TME) cell-infiltrating characteristics of these modification patterns were systematically assessed by ssGSEA and CIBERSORT algorithms. The principal component analysis algorithm based on the m6A scoring scheme was used to explore the m6A modification patterns of individual tumors with immune responses. The weighted correlation network analysis and univariable and multivariable Cox regression analyses were applied to identify m6A-modified gene signatures. The single-cell expression dataset of CRC samples was used to explore the tumor microenvironment affected by these signatures.Results: Three distinct m6A modification patterns with significant recurrence-free survival (RFS) were identified in 804 CRC patients. The TME characterization revealed that the m6A modification pattern with longer RFS exhibited robust immune responses. CRC patients were divided into high- and low-score subgroups according to the m6A score individually, which was obtained from the m6A-related signature genes. The patients with low m6A scores had both longer RFS and overall survival (OS) with altered immune cell infiltration. Notably, m6A-modified genes showed significant differences related to the prognosis of CRC patients in the meta-GEO cohort and TCGA cohort. Single-cell expression indicated that ALVRL1 was centrally distributed in endothelial tip cells and stromal cells.Conclusion: The m6A modification plays an indispensable role in the formation of TME diversity and complexity. Importantly, the signatures (TOP2A, LRRC58, HAUS6, SMC4, ACVRL1, and KPNB1) were identified as m6A-modified genes associated with CRC recurrence, thereby serving as a promising predictive biomarker or therapeutic target for patients with CRC recurrence.

Transient processes that occur in pumped storage power plants can cause high-pressure conditions, which in turn can result in vibrations in the pump–turbine structure and even damage to structural components. It is therefore crucial to research the transient process of the large pump–turbine units and the flow-induced vibrations of the structural components. The three-dimensional flow field and structural field models of a high-head prototype pump–turbine were constructed to study its flow characteristics and structural characteristics under the turbine start-up. Calculations and analyses were performed on the pressure variation and the flow-induced stress concentrations of the pump–turbine during start-up in turbine mode. The simulated pressure distributions during the turbine start-up were mapped onto the finite element calculation model of the structures of the pump–turbine to calculate the flow-induced stress concentrations. This study provides a reference to improve the design and operation of high-head prototype pump–turbines based on the findings of the flow and structural characteristics.

The thrust bearing, as the only part bearing the axial load, is extremely important in vertical hydroelectric generating units. Its working condition directly affects the safe and reliable operation of the hydroelectric generating unit. However, during operation, the oil film is easily damaged under the influence of complex factors. Installation deviation is a key point that can cause temperature and pressure changes in the oil film, affecting the force on the bearing. This article takes the thrust bearing model of the 1000 MW Francis turbine unit of the Baihetan Power Station as the research object. Based on the fluid–solid coupling theory and CFD technology, the oil film characteristics of thrust bearings are analyzed, and the influence of inclination angles and installation deviation on the oil film flow performance of thrust bearings is discussed. The results show that as the inclination angle changes from 0.0030° to 0.0048°, the axial force changes from 856 t to 368 t, and there is an approximate linear correlation between them. The radial installation deviation has an effect on the axial force. Under the optimal working condition of an inclination angle of 0.0039°, when the radial deviation of the pad changes from 0 mm to 1 mm, the axial force changes from 1573 t to 1275 t. In the process of unit installation, it is necessary to pay attention to the installation deviation of the pad. The results provide guidance for the installation of the bearing, which helps to ensure the safe and stable operation of the station.

In this paper, a 1000 MW Francis turbine was used to study the influences of uneven clearance distribution caused by various radial installation deviations on the hydraulic thrust of a runner under the rated operating condition with steady-state CFD analysis. Then, the influences of radial installation deviation on the pressure pulsations of the runner and the fluid domains most affected by the deviation were investigated via unsteady CFD calculation. The results show that the radial hydraulic force on the chambers increased linearly with the increase in the radial installation deviation. Additionally, the high-pressure zone was not located in the same position as the radial deviation. With increasing values of the radial installation deviation, the high-pressure zone rotated along the opposite direction of the rotating direction of the runner. This study also found that the flow in the upper crown chamber was most affected by radial installation deviation and that the percentage of high frequencies of the pressure pulsations increased with the flow in the clearances.

BackgroundColorectal cancer (CRC) is one of the most common malignancies and its incidence and mortality are increasing yearly. 5-Fluorouracil (5-FU) has long been used as a standard first-line treatment for CRC patients. Although 5-FU-based chemotherapy is effective for advanced CRC, the consequent resistance remains a key problem and causes the poor prognosis of CRC patients. Thus, there is an urgent need to identify new biomarkers to predict the response to 5-FU-based chemotherapy.MethodsCRC samples were retrieved from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). The immune-related genes were retrieved from the ImmPort database. Single-cell sequencing results from colorectal cancer were obtained by the ArrayExpress database. 5-FU resistance-related genes were filtered and validated by R packages. ESTIMATE algorithms were used to assess the tumor microenvironment (TME). KEGG and GO analysis were performed to explore the biological signaling pathway for resistant-response patients and sensitive-response patients in the tumor microenvironment. pRRophetic algorithms were used to predict 5-FU sensitivity. GSEA and GSVA analysis was performed to excavate the biological signaling pathway of the RBP7 gene.ResultsNine immune-related genes were identified to be associated with 5-FU resistance and poor disease-free survival (DFS) of CRC patients and the signature of these genes was developed in a DFS-prognostic model. Four immune-related genes were determined to be associated with 5-FU resistance and overall survival (OS) of CRC patients. The signature of these genes was developed an OS-prognostic model. ESTIMATE scores showed a significant difference between 5-FU resistant and 5-FU sensitive CRC patients. Resistant-response patients and sensitive-response patients to 5-FU based chemotherapy showed different GO and KEGG enrichment on the tumor microenvironment. RBP7, as a tumor immune microenvironment (TIME) related gene, was found to have the potential of predicting chemotherapy resistance and poor prognosis of CRC patients. GSEA analysis showed multiple signaling differences between the high and low expression of RBP7 in CRC patients. Hypoxia and TNFα signaling via NFκB gene sets were significantly different between chemotherapy resistant (RBP7High) and chemotherapy sensitive (RBP7Low) patients. Single-cell RNA-seq suggested RBP7 was centrally distributed in endothelial stalk cells, endothelial tip cells, and myeloid cells.ConclusionsImmune-related genes will hopefully be potential prognostic biomarkers to predict chemotherapy resistance for CRC. RBP7 may function as a tumor microenvironment regulator to induce 5-FU resistance, thereby affecting the prognosis of CRC patients.

To study the influence of the axial installation deviation of the runner on the hydraulic axial force of the 1000 MW Francis turbine unit, geometric models of the full flow passage of the Francis turbine with the runner sinking in the axial direction by 0, 0.5, 1, 1.5, 2.5, 4, and 5.5 mm were established. The geometric models of the upper crown clearance, lower band clearance, and pressure balance pipes were also built. The SST turbulence model was used in the CFD setup to numerically simulate the flow in the Francis turbine with different runner installation sinking values. The results show that the hydraulic axial force on the inner surface of the runner remains stable when the runner is lowered. The hydraulic axial force on the entire runner surface and the outer surface of the lower band decreases, and the hydraulic axial force on the outer surface of the upper crown clearance increases. All of these hydraulic axial forces gradually tend to stabilize as the amount descending from the runner increases. To study the reasons for the changes in hydraulic axial forces, the streamlines and fluid fields of different sections in the flow passage were analyzed in detail. It was found that periodic changes of vortices were generated in the clearance due to the influences of the geometric shape and wall rotation. These vortices affect the distribution of velocity and pressure and, thus, determine the hydraulic axial forces. The runner axial installation deviation has little influence on the streamlines, pressure, and velocity distribution in each flow passage, and only changes the velocity and pressure in the upper crown clearance and lower band clearance. Therefore, the axial installation deviation of the runner has a great effect on the hydraulic axial force on the outer surface of the upper crown and lower band and has a smaller impact on the runner passage and the hydraulic axial force on the inner surface of the runner. The conclusions in this study can be adopted as references for the installation accuracy control of other hydraulic Francis turbine units.

Objective: In this study, we aimed to develop an amino-terminal fragment (ATF) peptide-targeted liposome carrying β-elemene (ATF24-PEG-Lipo-β-E) for targeted delivery into urokinase plasminogen activator receptor-overexpressing bladder cancer cells combined with cisplatin (DDP) for bladder cancer treatment. Methods: The liposomes were prepared by ethanol injection and high-pressure microjet homogenization. The liposomes were characterized, and the drug content, entrapment efficiency, and in vitro release were studied. The targeting efficiency was investigated using confocal microscopy, ultra-fast liquid chromatography, and an orthotopic bladder cancer model. The effects of ATF24-PEG-Lipo-β-E combined with DDP on cell viability and proliferation were evaluated by a Cell Counting Kit-8 (CCK-8) assay, a colony formation assay, and cell apoptosis and cell cycle analyses. The anticancer effects were evaluated in a KU-19-19 bladder cancer xenograft model. Results: ATF24-PEG-Lipo-β-E had small and uniform sizes (˜79 nm), high drug loading capacity (˜5.24 mg/mL), high entrapment efficiency (98.37 ± 0.95%), and exhibited sustained drug release behavior. ATF24-PEG-Lipo-β-E had better targeting efficiency and higher cytotoxicity than polyethylene glycol (PEG)ylated β-elemene liposomes (PEG-Lipo-β-E). DDP, combined with ATF24-PEG-Lipo-β-E, exerted a synergistic effect on cellular apoptosis and cell arrest at the G2/M phase, and these effects were dependent on the caspase-dependent pathway and Cdc25C/Cdc2/cyclin B1 pathways. Furthermore, the in vivo antitumor activity showed that the targeted liposomes effectively inhibited the growth of tumors, using the combined strategy. Conclusions: The present study provided an effective strategy for the targeted delivery of β-elemene (β-E) to bladder cancer, and a combined strategy for bladder cancer treatment.

Objective: This study aimed to develop a new polyethylene glycol (PEG)ylated β-elemene liposome (PEG-Lipo-β-E) and evaluate its characterization, pharmacokinetics, antitumor effects and safety in vitro and in vivo. Methods: The liposomes were prepared by ethanol injection and high-pressure micro-jet homogenization. Characterization of the liposomes was conducted, and drug content, entrapment efficiency (EE), in vitro release and stability were studied by ultra-fast liquid chromatography (UFLC) and a liquid surface method. Blood was drawn from rats to establish the pharmacokinetic parameters. The anticancer effect was evaluated in a KU-19-19 bladder cancer xenograft model. Histological analyses were performed to evaluate safety. Results: The PEG-Lipo-β-E showed good stability and was characterized as 83.31 ± 0.181 nm in size, 0.279 ± 0.004 in polydispersity index (PDI), −21.4 ± 1.06 mV in zeta potential, 6.65 ± 0.02 in pH, 5.024 ± 0.107 mg/mL in β-elemene (β-E) content, and 95.53 ± 1.712% in average EE. The Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) indicated the formation of PEG-Lipo-β-E. Compared to elemene injection, PEG-Lipo-β-E demonstrated a 1.75-fold decrease in clearance, a 1.62-fold increase in half-life, and a 1.76-fold increase in area under the concentration-time curves (AUCs) from 0 hour to 1.5 hours (P < 0.05). PEG-Lipo-β-E also showed an enhanced anticancer effect in vivo. Histological analyses showed that there was no evidence of toxicity to the heart, kidney, liver, lung or spleen. Conclusions: The present study demonstrates PEG-Lipo-β-E as a new formulation with ease of preparation, high EE, good stability, improved bioavailability and antitumor effects.

A significant number of processing cores in any many-core systems nowadays and likely in the future have to be switched off or forced to be idle to become dark cores, in light of ever increasing power density and chip temperature. Although these dark cores cannot make direct contributions to the chip's throughput, they can still be allocated to applications currently running in the system for the sole purpose of heat dissipation enabled by the temperature gradient between the active and dark cores. However, allocating dark cores to applications tends to add extra waiting time to applications yet to be launched, which in return can have adverse implications on the overall system performance. Another big issue related to dark core allocation stems from the fact that application characteristics are prone to undergo rapid changes at runtime, making a fixed dark core allocation scheme less desirable. In this paper, a runtime dark core allocation and dynamic adjustment scheme is thus proposed. Built upon a dynamic programming network (DPN) framework, the proposed scheme attempts to optimize the performance of currently running applications and simultaneously reduce waiting times of incoming applications by taking into account both thermal issues and geometric shapes of regions formed by the active/dark cores. The experimental results show that the proposed approach achieves an average of 61% higher throughput than the two state-of-the-art thermal-aware runtime task mapping approaches, making it the runtime resource management of choice in many-core systems.

It is not uncommon for pump-turbine units in pumped storage power plants to experience load rejections due to the sudden disconnection of the generator from the power grid. Load rejection can suddenly increase the rotating speed of the pump-turbine and cause strong pressure fluctuations in the flow passage of the pump-turbine unit. During load rejection, the strong pressure fluctuations caused by the water hammer effect can cause strong structural vibrations, high stresses and even damage to the turbine runner, head cover, stay ring, bottom ring, head cover bolts and bottom ring bolts. In order to study, in detail, the flow-induced stress characteristics of the prototype pump-turbine unit, and the pressure variations during load rejection in a high-head pumped storage power plant were measured first. Then the measured data were used to set up computational fluid dynamics (CFD) simulations in the entire flow passage of the prototype pump-turbine and to calibrate the simulation results. The calculated pressure distributions in the flow passage during load rejection were exported and mapped on the finite element model of the stationary structures of the pump-turbine unit so that the flow-induced stresses on the head cover, stay ring, bottom ring, head cover bolts and bottom ring bolts can be calculated. The results of the analysis show that the maximum stresses in the head cover bolts and bottom ring bolts are located on the rounded corner of the bolt near the stay ring and that the stresses in the bolts vary with time during load rejection. The maximum stresses of the head cover bolts are higher than the maximum stresses of the bottom ring bolts, and the maximum stresses of the bolts are above two-thirds of the yield strength of the bolt material. It is recommended to use larger nominal diameter bolts to avoid damage to the connecting bolts of the pump-turbine unit.

In order to ensure stable grid operatiFon and improve power quality, active or passive load rejection of pumped storage power stations (PSPS) inevitably occurs from time to time. The rapid closing of the guide vanes will cause drastic changes in pressure pulsations in the flow channel of the pump-turbine (PT) unit. The high-level pressure pulsations during load rejection transfer to the entire flow passage of the PT unit and generate strong vibrations on the head-cover and the connecting bolts. In this study, the 1D/3D joint simulation of the pipeline in a pumped storage power station and the turbine flow channels including the flow domains of the runner, crown chamber, band chamber, upper and lower labyrinths and pressure balance tubes is carried out first. Then, by applying the calculated pressure loads on the head-cover, stay vanes and bottom ring of the PT unit, the flow-induced dynamic behavior of the structures including the head-cover bolts is analyzed in detail. The results demonstrate that pressure loads on head-cover bolts change dramatically during the load rejection process. The flow-induced deformation of the inner head-cover during the load rejection is larger than that of other structures, and the flow-induced displacement and stress of different head-cover bolts are not uniform. The achieved conclusions in this study can be a useful reference for the design and operation of head-cover bolts for other PT units and high-head Francis turbine units.

Pumped storage-power plants play an extremely important role in the modern smart grid due to their irreplaceable advantages in load peak-valley regulation, frequency modulation, and phase modulation. The number of start-stops per day of pump-turbine units is therefore also increasing. During the start-up transient process in turbine mode, the complex flow in runner passage, crown and band chambers, and seal labyrinth is able to induce severe vibration of non-rotating structures such as head cover, stay-ring, and pose a threat to the safe operation of the pump-turbine unit. In this article, the flow-induced vibration of the structures of a pump-turbine unit during its start-up process in turbine mode is studied. In the first place, this investigation establishes a three-dimensional model of the full flow passage and carries out a full three-dimensional CFD calculation based on one-dimensional pipeline calculation results for the start-up transient process. In the next place, by applying the fluid–structure interaction calculation method, the finite element analysis of non-rotating components of the pump-turbine unit is carried out. The flow-induced stresses and deformations of head cover, stay-ring, etc., are obtained and analyzed. The results reveal that the maximum deformation of the non-rotating structures is located at the inner edge of the head cover while the maximum stress appears at the trailing edge fillet of a stay vane. In summary, the dynamic stress of the non-rotating structures changes largely during the start-up process. The stress is strongly related to the axial thrust caused by the fluid flow. The achieved results can provide guidance for further fatigue life assessment of non-rotating structures and contribute to the structural safety design of pump-turbine units.

Understanding the dynamics of vegetation responses to climate change can provide important information for environmental management. The Qilian Mountain Nature Reserve in Northwest China, a high-altitude mountainous region that is of critical ecological importance, has been affected by drastic climate change. However, the response of vegetation to climate change in this area has not been established. This study aims to address three unanswered questions. First, what is the relative importance of temperature and precipitation change in driving regional vegetation change? Second, how does this vegetation–climate relationship manifest itself across different timescales (e.g., seasonal)? Third, what is the spatial heterogeneity of the vegetation–climate relationship? Based on MODIS data and daily meteorological data from 41 stations within and adjacent to the reserve, we used Ensemble Empirical Mode Decomposition (EEMD), Theil-Sen median trend analysis, the Mann-Kendall nonparametric test, and Pearson correlation analysis to study the evolution of temperature, precipitation, and the normalized difference vegetation index (NDVI). The key results are as follows: (1) during 1985–2019, the temperature in the reserve has increased by an average of 0.048 ℃/a, with the largest average annual increases occurring in spring (0.069 ℃) and summer (0.056 ℃); (2) during the same period, precipitation in the reserve increased by an average of 1.17 mm/a, with the largest annual increases occurring in autumn (0.669 mm) and summer (0.545 mm); (3) during 2001–2019, the NDVI increased by an average of 0.004/a; an average annual increase was experienced in all seasons, although the largest increase occurred in summer; (4) there is a statistically significant positive correlation (0.619) between the NDVI and temperature at the annual scale; (5) in contrast, the correlation between the NDVI and precipitation is weaker and not statistically significant (0.368), which indicates that temperature is the dominant factor affecting vegetation changes in the reserve; (6) there exist seasonal differences in the vegetation–climate relationship. The positive correlation between NDVI and temperature is strongest in spring whereas the positive correlation between NDVI and precipitation is strongest in summer; (7) the vegetation–climate relations demonstrate a degree of spatial heterogeneity driven by variability in climate factors and ecosystems. The value of this research is that it analyzes the response characteristics of vegetation to climate change using multiple methods and at multiple scales, providing a useful reference for understanding vegetation changes and their response to climate change in high-altitude mountain regions.

Cancer progression and metastases are the leading causes of poor outcomes in patients with colon cancer. Colon cancer metastasis is a multigene, multistep, multistage complex process in which target genes, microRNAs, epithelial-stromal transformation, tumour stem cells, the tumour microenvironment, and various cell signalling pathways are implicated in the progression and metastasis of colon cancer. Although conventional therapies have made significant advances in treating the progression and metastasis of colorectal cancer, they have failed to improve survival outcomes. Natural compounds may have more significant potential in preventing and treating colon cancer. Active natural compounds exert their antitumor effects by inducing tumour cell differentiation, promoting tumour cell apoptosis, inhibiting tumour vascular growth, and regulating immunity. Natural compounds, combined with conventional therapies, can target mutant genes and various cellular signalling pathways, inhibit epithelial-stromal transformation, and improve the tumour microenvironment to inhibit tumour progression and metastasis. The synergism of natural compounds and conventional therapeutics has the potential to become a promising therapy for treating colorectal cancer progression and metastases.

Adelphocoris suturalis Jakovlev (Hemiptera: Miridae) is an omnivorous agricultural pest that has severe economic impacts on a diverse range of agricultural crops. Although the targeted disruption of reproductive development among insects has been proposed as a novel control strategy for pest species, the current understanding of the physiology and molecular mechanisms of A. suturalis reproduction is very limited. In this study, we isolated a putative A. suturalisaspartic protease (AsAP) gene that is highly expressed in the fat body and ovaries of sexually mature females. The double-stranded RNA (dsRNA)-mediated knockdown of AsAP suppressed ovarian development and negatively impacted female fertility, which suggested that it plays an essential role in A. suturalis reproduction. The results of this study could help to expand our understanding of A. suturalis reproductive development and have the potential to facilitate the development of effective strategies for the better control of this pest species.

The Yellow River has a high sand content, and sand deposition in the pipelines behind the pumping station occurs from time to time. It is of great significance to reasonably predict the critical velocity of the small-angled V-inclined water transportation pipes. In this study, a Eulerian multiphase model was employed to simulate the solid–liquid two-phase flow. Based on the conservation of the sand transport rate, the critical velocity of the V-inclined pipe was predicted. The effects of simulated pipeline length, pipe inclination and particle size were investigated. The results show that when the simulated pipeline length reached a certain value, it did not affect the prediction of the critical velocity of the overall pipeline. The ±2∘ pipe inclination had a negligible effect on the critical velocity for transporting small-sized particles, but it led to the nonuniform and asymmetrical distribution of liquid velocity and sand deposition at the different cross-sections. As the particle size increased, the critical velocity also increased. However, the influence of particle size on the critical velocity is currently complicated, resulting in a large difference between numerical simulation and empirical formulas when transporting large-sized particles. Accurate prediction of critical velocity is important for long-distance water transportation pipelines to prevent sand deposition and reduce costs.

In recent years, large-capacity, high-head pump–turbine units have been developed for pumped storage power plants to effectively utilise water energy and store large amounts of electricity. Compared with the traditional Francis turbine unit, the radial distance between the trailing edge of the guide vanes and the leading edge of runner blades of high-head pump–turbine unit is smaller, so the rotor–stator interaction and the corresponding pressure fluctuations in the vaneless space of pumped storage units are more intense. The pressure fluctuations with high amplitudes and high frequencies induced by rotor–stator interaction (RSI) become the main hydraulic excitation source for the structures of the unit and may cause violent vibration and fatigue damage to structural components, and seriously affect the safe operation of the units. In this paper, the RSI of a high-head pump–turbine in turbine mode of operation is studied in detail by means of site measurement and full three-dimensional unsteady simulations. The results of RSI-induced pressure fluctuations in turbine mode are analysed experimentally and numerically. The accuracy of the numerical calculations is verified by comparing with the measured results, and the variation law of RSI is deeply analysed. The results show that the pressure fluctuations in the vaneless space are affected by the wake of the guide vane, the rotating excitation of the runner, the low-frequency excitation of the draft tube, and the asymmetric characteristics of the incoming flow of the spiral case, and shows significant differences in spatial position. The findings of the investigation are an important and valuable reference for the design and safe operation of the pumped storage power station. It is recommended to design the runner with inclined inlets to reduce the amplitudes of RSI-induced pressure fluctuations and to avoid operating the pump–turbine units under partial load for long periods of time to reduce the risk of pressure fluctuation induced severe vibration on the structures.

During the load rejection transient process of the prototype pump turbine units, the pressure fluctuations of the entire flow passage change drastically due to the rapid closing of guide vanes. The extremely unsteady pressure distribution in the flow domains including the crown chamber and the band chamber may cause a strong vibration on the stationary structures of the unit and result in large dynamic stress on the head cover, stay ring and bottom ring. In this paper, the numerical fluid dynamic analysis of the entire flow passage of a reversible prototype pump turbine during load rejection was performed. The flow characteristics in the runner passage, crown chamber, band chamber, seal labyrinths and balance tubes are analysed. The corresponding unsteady flow-induced dynamic behaviour of the head cover, stay vanes and bottom ring was investigated in detail. The analysed results show that the total deformation of the inner edge of the head cover closed to the main shaft is larger than that of other stationary structures of the unit during the load rejection. The maximum stress of the stay ring is larger than that of the head cover and the bottom ring and the maximum equivalent stress is located at the fillet of the stay vane trailing edge. The fluid–structure coupling calculation method and the analysed results can provide guidance for the design of stationary components of hydraulic machinery such as pump turbines, Francis turbines and centrifugal pumps with different heads.

Nowadays, pump-turbine units have to experience multiple start-stops every day to balance the power production and consumption on the grid. During the transient process of turbine start-up, the hydraulic forces applied to the head-cover would change dramatically and induce high-level stresses on the head-cover bolts. As key components of large hydraulic turbine units, the head-cover bolts are subjected to tens of thousands of tonnes of hydraulic excitation force during operation. Special attention should be paid to the design of the head-cover bolts of large hydraulic pump-turbine units because these units have high water heads and high hydraulic excitation forces. Therefore, the safe design of the head-cover bolts is extremely important to maintain the operational safety of the whole unit. This paper investigates the flow-induced stress characteristics of the head-cover bolts during turbine start-up in a large prototype pump-turbine unit. A complete 3D fluid model and a corresponding 3D structural model, including the head-cover bolts of the pump-turbine unit, were created. The fluid–structure coupling method was used to calculate the structural stresses caused by fluid flow during turbine start-up. The pressure files during turbine start-up calculated by the CFD tool were transferred and mapped to the finite element model of the structural components of the pump-turbine unit. Subsequently, the flow-induced stress characteristics of the head-cover bolts were numerically simulated. The simulation results showed that the hydraulic excitation force on the head-cover bolts increased significantly during turbine start-up, and the displacement and the stress distributions of different head-cover bolts were not uniform. The calculation methods and conclusions in this paper can also be applied to evaluate the flow-induced stress characteristics of head-cover bolts for similar hydraulic pump-turbine units.

ObjectiveColorectal cancer is a malignant tumor of the digestive system with high morbidity and mortality. 5-fluorouracil remains a widely used chemotherapeutic drug in the treatment of advanced colorectal cancer, but chemotherapy drugs are prone to develop drug resistance, p53 deletion or mutation is an important reason for the resistance of colorectal cancer cells to 5-fluorouracil. β-elemene has been proved to have the potential of reverse chemotherapy drug resistance, but the mechanism is unknown. This study aimed to investigate the effect of β-elemene to 5-fluorouracil in drug-resistant p53-deficient colorectal cancer cells HCT116p53–/–, and determine the possible molecular mechanism of β-elemene to reverse 5-fluorouracil resistance.MethodsThe effect of β-elemene on HCT116p53–/– cell activity was detected by Cell counting Kit-8. Cell proliferation was detected by monoclonal plate. The apoptosis was detected by flow cytometry and western blot. The autophagy was detected by western blot, immunofluorescence and transmission electron microscope. Determine the role of Cyclin-related protein Cyclin D3 in β-elemene reversing the resistance of HCT116p53–/– to 5-fluorouracil was detected by overexpression of Cyclin D3. The effect of β-elemene on the tumorigenic ability of p53-deficient colorectal cancer cells was detected establishing HCT116p53–/– all line xenograft model.ResultsFor p53 wildtype colorectal cancer cells, β-elemene could augment the sensitivity of 5-fluorouracil, for p53-deficient colorectal cancer cells, β-elemene significantly inhibited cell proliferation in a concentration-dependent manner, and reversed the resistance of HCT116p53–/– to 5-fluorouracil by inducing pro-death autophagy and Cyclin D3-dependent cycle arrest.Conclusionβ-elemene enhances the sensitivity of p53 wild-type cells to 5-fluorouracil, β-elemene can reverse the resistance of HCT116p53–/– to 5-fluorouracil by inducing pro-death autophagy and Cyclin D3-dependent cycle arrest in p53-deficient colorectal cancer, which will provide a new method for the treatment of p53 deletion colorectal cancer patients.

Balancing the relationship between rural development and the protection of water resources is a challenging undertaking. This study develops a coupling coordination degree (CCD) model to examine the non-linear interaction between rural development and water environment in the 11 prefectures of Gansu, northwestern China. There are three key findings. First, economic development is the key driver of rural development, whereas social development has relatively little impact. For the water environment subsystem, improved water efficiency has been the key contributor, whereas environmental carrying capacity is secondary. Second, the CCD increased steadily in the studied period, which suggests that the relationship between rural development and water environment has gradually changed from antagonistic to mutually beneficial. However, this change is not occurring rapidly and in fact shows signs of slowing. Third, the complex spatial differences of the CCD are related to the level of economic and social development, the process of urban–rural integration, and regional natural conditions. The findings of this study have great significance for further quantitative analysis of the interaction and mutual feedback mechanism between the rural economy and the water environment in China and support evidence-based policymaking.

The human oral cavity is a complex ecosystem harboring hundreds species of microbes that are largely living on the tooth surfaces as dental biofilms. Most microbes in dental biofilms promote oral health by stimulating the immune system or by preventing invasion of pathogens. Species diversity, high cell density and close proximity of cells are typical of life in dental biofilms, where microbes interact with each other and develop complex interactions that can be either competitive or cooperative. Competition between species is a well-recognized ecological force to drive microbial metabolism, species diversity and evolution. However, it was not until recently that microbial cooperative activities are also recognized to play important roles in microbial physiology and ecology. Importantly, these interactions profoundly affect the overall biomass, function, diversity and the pathogenesis in dental biofilms. It is now recognized that every human body contains a personalized oral microbiome that is essential to maintaining the oral health. Remarkably, the indigenous species in dental biofilms often maintain a relatively stable and harmless relationship with the host, despite regular exposure to environmental perturbations and the host defense factors. Such stability or homeostasis results from a dynamic balance of microbial-microbial and microbial-host interactions. Under certain circumstances, however, the homeostasis may breakdown, predisposing a site to diseases. In this review, we describe several examples of microbial interactions and their impacts on the homeostasis and pathogenesis of dental biofilms. We hope to encourage research on microbial interactions in the regulation of the homeostasis in biofilms.

Ferroptosis is an iron-dependent, oxidative cell death, and is characterized by iron-dependent accumulation of reactive oxygen species (ROS) within the cell. It has been implicated in various human diseases, including cancer. Recently, ferroptosis, as a non-apoptotic form of cell death, is emerging in specific cancer types; however, its relevance in colorectal cancer (CRC) is unexplored and remains unclear. Here, we showed that ferroptosis inducer RSL3 initiated cell death and ROS accumulation in HCT116, LoVo, and HT29 CRC cells over a 24 h time course. Furthermore, we found that ROS levels and transferrin expression were elevated in CRC cells treated with RSL3 accompanied by a decrease in the expression of glutathione peroxidase 4 (GPX4), indicating an iron-dependent cell death, ferroptosis. Overexpression GPX4 resulted in decreased cell death after RSL3 treatment. Therefore, RSL3 was able to induce ferroptosis on three different CRC cell lines in vitro in a dose- and time-dependent manner, which was due to increased ROS and an increase in the cellular labile iron pool. Moreover, this effect was able to be reversed by overexpression of GPX4. Taken together, our results suggest that the induction of ferroptosis contributed to RSL3-induced cell death in CRC cells and ferroptosis may be a pervasive and dynamic form of cell death for cancer treatment.

A new GaN light-emitting diode (LED) structure, which has a 300-nm aluminum-doped zinc oxide transparent current spreading layer epitaxial layer grown on a standard GaN LED epistack used in commercial GaN LED products, shows improved power vs. voltage (P-V) linearity and is suitable for high-data rate visible light communication. Experimentally, a single GaN-based blue LED with a mesa diameter of 150 μm and a maximum optical power of 42 mW demonstrates a 3-Gb/s free-space data transmission speed. The modulation bandwidth reaches 600 MHz under the present experimental setup. The present work proves the practicability of enhancing the LED's free-space data transmission ability through a P-V linearity improvement at the chip level.

In this paper, for the first time, we propose the use of a hybrid post equalizer in a high-order carrierless-amplitude-and-phase-modulation-based visible light communication (VLC) system. The hybrid equalizer consists of a linear equalizer, a Volterra-series-based nonlinear equalizer, and a decision-directed least mean squares equalizer to simultaneously mitigate the linear and nonlinear distortions of the VLC system. A commercially available red-blue-green-yellow light-emitting diode (RBGY LED) is utilized for four-wavelength multiplexing. By the hybrid equalizer, an aggregate data rate of 8 Gb/s is experimentally achieved over a 1-m indoor free-space transmission with the bit error rate (BER) below the 7% forward error correction (FEC) limit of 3.8 × 10-3. To the best of our knowledge, this is the highest data rate ever reported in high-speed VLC systems.

The light-emitting diode nonlinearity in visible light communication (VLC) systems is considered to be a major problem that deteriorates system performance. In this paper, we experimentally demonstrate a high-speed WDM CAP64 VLC system employing a Volterra series-based nonlinear equalizer to mitigate the nonlinear effect. A modified cascaded multimodulus algorithm (M-CMMA) is utilized to calculate the error function and update the weights of the nonlinear equalizer without using training symbols. An aggregate data rate of 4.5 Gb/s is successfully achieved over 2-m indoor free-space transmission with a bit error rate (BER) below the 7% forward error correction limit of 3.8 × 10-3. With the Volterra nonlinear equalizer, the Q factor of the VLC system is 1. 6 dB better than that without using the nonlinear equalizer, and the transmission distance is also increased by about 110 cm at the BER of 3.8 × 10-3. To the best of our knowledge, this is the first time that the Volterra nonlinear equalizer is utilized for high-speed carrierless amplitude and phase (CAP) modulation-based VLC systems.

In this paper, we present a high-speed visible light communication (VLC) system based on a single commercially available phosphorescent white light-emitting diode (LED). In this system, a preequalization circuit is used to extend the modulation bandwidth, and a differential output receiver is utilized to reduce the system noise. With adaptive bit and power allocation and orthogonal frequency-division multiplexing (OFDM), we experimentally demonstrated a 2.0-Gb/s visible light link over 1.5-m free-space transmission, and the BER is under a preforward error correction limit of 3.8×10-3. To the best of our knowledge, this is the highest white-light VLC data rate using a single phosphorescent white LED.

To have a safe structural design, an analysis of the dynamic behavior of a Francis turbine runner with consideration of the added mass effects of surrounding water is necessary during design phase. Both in design and at off-design operations, large-scale forms of attached cavitation may appear on runner blades and can change the added mass effects of the surrounding fluid in relation to a single water domain. Consequently, a numerical investigation of the modal response of a Francis runner has been carried out by reproducing the presence of various sizes of leading edge cavitation (LEC) and trailing edge cavitation (TEC). The fluid−structure interaction problem has been solved by means of an acoustic-structural coupling method. The calculated added mass effects with cavitation have been compared with those corresponding to the pure water condition without cavitation. Firstly, a single blade has been investigated to evaluate the level of significance for the proposed cavity shapes and dimensions. Afterwards, based on the results obtained, the complete runner structure has been considered, factoring in similar cavity shapes and locations. The results prove that significant added mass effects are induced on the entire runner by the attached cavitation that increase the natural frequencies of the first modes. Moreover, the added mass effects increase with cavity size and amplitude of blade deformation below the cavity.