Search

In order to solve the cold-starting problem and improve the intake and exhaust pipe temperatures of diesel engines under cold-starting and low- and medium-speed conditions, this paper proposes a twice-open control method for a hydraulic variable valve system. First, a hydraulic variable valve system that can realize a fully variable valve lift and phase angle is applied to replace the original intake system in order to meet the air intake requirements of different conditions. Then, a twice-open control method in which the intake valve opens two times at the exhaust stroke and intake stroke is proposed to improve the intake pipe temperature and solve the cold-starting problem. This paper contains a numerical work analysis. A GT-POWER model is constructed to validate the intake valve twice-open control method. The cylinder pressure, cylinder temperature, intake pipe pressure, and intake pipe temperature are obtained and compared between the original intake valve system and the hydraulic variable valve system with the proposed intake valve twice-open control method. The results show that the twice-open control method can increase the intake pipe temperature to 260 K or even higher, which can improve the cold-starting performance and the exhaust temperature at low and medium speeds. At the same time, the performance under low- and medium-speed conditions is improved. [ABSTRACT FROM AUTHOR]

Phosphates play a crucial role in drug design, but their negative charge and high polarity make the transmembrane transport of phosphate species challenging. This leads to poor bioavailability of phosphate drugs. Combretastatin-A4 phosphate (CA4P) is such an anticancer monoester phosphate compound, but its absorption and clinical applicability are greatly limited. Therefore, developing carrier systems to effectively deliver phosphate drugs like CA4P is essential. Anion receptors have been found to facilitate the transmembrane transport of anions through hydrogen bonding. In this study, we developed a tripodal hexaurea anion receptor (L1) capable of binding anionic CA4P through hydrogen bonding, with a binding constant larger than 104 M−1 in a DMSO/water mixed solvent. L1 demonstrated superior binding ability compared to other common anions, and exhibited negligible cell cytotoxicity, making it a promising candidate for future use as a carrier for drug delivery. [ABSTRACT FROM AUTHOR]

Hessenberg differential algebraic equations (Hessenberg-DAEs) with a high index play a critical role in the modeling of mechanical systems and multibody dynamics. Motivated by the widely used Lie-group differential algebraic equation (LGDAE) method, which handles index-2 systems, we first propose a modified extended Lie-group differential algebraic equation (MELGDAE) method for solving index-3 Hessenberg-DAEs and then provide a theoretical analysis to deepen the foundation of the MELGDAE method. Moreover, the performance of the MELGDAE method is compared with the standard methods RADAU and MEBDF on index-2 and -3 DAE systems, and it is demonstrated that the MELGDAE integrator exhibits a competitive performance in terms of high accuracy and the preservation of algebraic constraints. In particular, all differential variables in index-3 Hessenberg-DAEs achieve second-order convergence using the MELGDAE method, which suggests the potential for extension to Hessenberg-DAEs with an index of 4 or higher. [ABSTRACT FROM AUTHOR]

The study of litter can provide an important reference for understanding patterns of forest nutrient cycling and sustainable management. Here, we measured litterfall (leaves, branches, etc.) from a wet, evergreen, broad-leaved forest in Ailao Mountains of southwestern China on a monthly basis for 11 years (2005–2015). We measured the total biomass of litter fall as well as its components, and estimated the amount of C, N, P, K, S, Ca, and Mg in the amount of litterfall. We found that: The total litter of evergreen, broadleaved forest in Ailao Mountains from 2005 to 2015 was 7.70–9.46 t/ha, and the output of litterfall differed between years. This provides a safeguard for the soil fertility and biodiversity of the area. The total amount of litterfall and its components showed obvious seasonal variation, with most showing a bimodal pattern (peak from March to May and October to November). The majority of litterfall came from leaves, and the total amount as well as its components were correlated with meteorological factors (wind speed, temperate and precipitation) as well as extreme weather events. We found that among years, the nutrient concentration was sorted as C > Ca > N > K > Mg > S > P. The nutrient concentration in the fallen litter and the amount of nutrients returned showed a decreasing trend, but the decreasing rate was slowed through time. Nutrient cycling was influenced by meteorological factors, such as temperature, precipitation, and wind speed, but the nutrient utilization efficiency is high, the circulation capacity is strong, and the turnover time is short. Our results showed that although there was nutrient loss in this evergreen, broad-leaved forest, the presence of forest litterfall can effectively curb potential ecological problems in the area. [ABSTRACT FROM AUTHOR]

Ecosystem services (ES) has an important place in sustainability science research as a powerful bridge between society and nature. Based on 513 papers correlated with ES in the field of green sustainable science and technology (GSST) indexed in ISI Web of Science database, we employ the bibliometric methods to analyze the disciplinary co-occurrence, keyword co-occurrence, partnerships, publication characteristics, co-citation, research themes, and transformative potential of these papers. The results show that innovation in research themes of the ES research in the GSST field is increasing rapidly in 2015–2018, while innovation in research themes is decreasing in 2018–2021. Moreover, keyword co-occurrence analysis indicates that the hot topics of previous research with respect to "environmental service", "capacity", "perception", "landscape", "forest management", "carbon sequestration", "contingent valuation", and "sustainable development". Recent hotspots include "blue carbon", "environmental impact", "coastal", "ecosystem services mapping", and "use/land cover change". Finally, the cluster analysis of co-cited references abstract thirteen largest clusters. The top six clusters are "mapping ecosystem service", "spatial gradient difference", "ecosystem service value", "water-related ecosystem service", "linking forest landscape model", and "culture ecosystem service". Moreover, the integration of spatial, value, environmental, and sociocultural dimensions may help to develop supportive policies, which is a future direction of ES research in the GSST field. [ABSTRACT FROM AUTHOR]

This paper constructs a mathematical model to study China's urban real estate markets, in which there are different types of demands from house buyers, and housing suppliers adopt the strategy of quality differentiation second-degree price discrimination. Our theoretical result shows that, in China's case, without government intervention in the housing market, it is almost inevitable that the prices of both housing and the related resources will rocket. To achieve the goal of "houses built for inhabitance", we put forward a policy scheme to achieve "houses built for inhabitance" in China's cities from the perspectives of "speculation limitation" and "price control". We also conduct a numerical analysis to consider the macroeconomic effects of these two policy solutions on the housing market, and we conclude that Chinese authorities should introduce a resale tax in the housing market and learn from Singapore's experience in housing market regulation. [ABSTRACT FROM AUTHOR]

Src family kinases (SFKs) are non-receptor tyrosine kinases and play a key role in regulating signal transduction. The mechanism of SFKs in various tumors has been widely studied, and there are more and more studies on its role in the kidney. Acute kidney injury (AKI) is a disease with complex pathogenesis, including oxidative stress (OS), inflammation, endoplasmic reticulum (ER) stress, autophagy, and apoptosis. In addition, fibrosis has a significant impact on the progression of AKI to developing chronic kidney disease (CKD). The mortality rate of this disease is very high, and there is no effective treatment drug at present. In recent years, some studies have found that SFKs, especially Src, Fyn, and Lyn, are involved in the pathogenesis of AKI. In this paper, the structure, function, and role of SFKs in AKI are discussed. SFKs play a crucial role in the occurrence and development of AKI, making them promising molecular targets for the treatment of AKI. [ABSTRACT FROM AUTHOR]

Metal salen/salophen complexes have been used as fluorescent probes for cell imaging with various metal centers. Herein we synthesized cryptand-type aluminum salophen complexes LAl3 and the corresponding mononuclear compound LAl. X-ray crystal diffraction verifies the cryptand-type structure of LAl3 with C3h symmetry. Both LAl3 and LAl show moderate green fluorescence with quantum yields of 0.17 and 0.05, respectively. The hydrophilic and cationic nature of these aluminum salophen complexes renders them enhanced cellular uptake. Both complexes are internalized into cells by energy-dependent pathways and they distribute in lysosomal organelles. [ABSTRACT FROM AUTHOR]

Although remanufacturing has great economic and environmental potential, internal cannibalization, and lack of consumer acceptance of remanufactured products prevent original equipment manufacturer (OEM) from realizing the full potential value through remanufacturing. Practices show that remanufactured products can realize their value by the donation, besides resale. Thus, this paper incorporates the donation of remanufactured products with government subsidy and presents an upgraded remanufacturing strategy to expand the demand for remanufactured products and weaken the internal cannibalization of remanufactured products. We respectively construct the two-period game model with and without upgraded remanufacturing and explore the effect of upgraded remanufacturing on production decision, economic and environmental benefits. The main conclusions are as follows. The donation subsidy is negatively related with the sale quantity of remanufactured products, but is positively related with the donation quantity of remanufactured products and the quantity of new products. The donation subsidy expands the demand for remanufactured products and weakens internal cannibalization of remanufactured products. Whether the upgraded remanufacturing strategy is profitable depends on the fixed cost of the remanufacturing. When consumers consider remanufactured products environmentally friendly, the government can realize an OEM's win-win situation where the economic and environmental benefits get improved by adjusting the donation subsidy. Otherwise, introducing upgraded remanufacturing makes the environment worse. Comparatively speaking, a low-cost and environmentally friendly manufacturer is relatively easier to achieve the win-win situation through donation subsidy. [ABSTRACT FROM AUTHOR]

The k-means problem has been paid much attention for many applications. In this paper, we define the uncertain constrained k-means problem and propose a (1 + ϵ) -approximate algorithm for the problem. First, a general mathematical model of the uncertain constrained k-means problem is proposed. Second, the random sampling properties of the uncertain constrained k-means problem are studied. This paper mainly studies the gap between the center of random sampling and the real center, which should be controlled within a given range with a large probability, so as to obtain the important sampling properties to solve this kind of problem. Finally, using mathematical induction, we assume that the first j − 1 cluster centers are obtained, so we only need to solve the j-th center. The algorithm has the elapsed time O ((1891 e k ϵ 2) 8 k / ϵ n d) , and outputs a collection of size O ((1891 e k ϵ 2) 8 k / ϵ n) of candidate sets including approximation centers. [ABSTRACT FROM AUTHOR]

Tourists' perceptions of various risks at their travel destinations have crucial implications for destination management organizations and other tourism industry practitioners, which is growing into an unprecedented concern in the post-pandemic era. The Internet has boosted the global homestay industry. The perceived risk of homestay tourists requires further attention from researchers to promote the sustainable development of the homestay industry, especially in the post-pandemic era. To supplement and enrich the literature, this study aims to explore the relationships between tourists' perceived risk, three dimensions of tourists' emotional solidarity with hosts (feeling welcome, sympathetic understanding, and emotional closeness), and their customer loyalty towards the homestay industry in the post-pandemic era by taking the homestay industry of Guangzhou, China as the context, and employing SmartPLS for the empirical analysis. The results indicate that perceived risk has a significantly negative impact on emotional solidarity and customer loyalty, while emotional solidarity has a significantly positive impact on customer loyalty and plays a partial mediating role in the relationship between perceived risk and customer loyalty. The theoretical contributions of the article and the practical implications of the findings for the sustainable development of the homestay industry are discussed. [ABSTRACT FROM AUTHOR]

A new generation of universal tools and languages for modeling and simulation multi-physical domain applications has emerged and became widely accepted; they generate large-scale systems of differential algebraic equations (DAEs) automatically. Motivated by the characteristics of DAE systems with large dimensions, high index or block structures, we first propose a modified Pantelides' algorithm (MPA) for any high order DAEs based on the Σ matrix, which is similar to Pryce's Σ method. By introducing a vital parameter vector, a modified Pantelides' algorithm with parameters has been presented. It leads to a block Pantelides' algorithm (BPA) naturally which can immediately compute the crucial canonical offsets for whole (coupled) systems with block-triangular form. We illustrate these algorithms by some examples, and preliminary numerical experiments show that the time complexity of BPA can be reduced by at least O (ℓ) compared to the MPA, which is mainly consistent with the results of our analysis. [ABSTRACT FROM AUTHOR]

Aberrant expression of programmed death ligand 1 (PD-L1) on tumor cells impedes antitumor immunity and instigates immune evasion. The remarkable efficacy of immune checkpoint blockade has been confirmed in various solid tumors. However, the correlation between PD-L1 expression and host immunological landscape remains of considerable controversy in non-small cell lung cancer (NSCLC). In the present study, PD-L1 expression and CD8+ tumor-infiltrating lymphocyte (TIL) infiltration levels were determined by immunohistochemistry (IHC) in tumor sections of 138 NSCLC patients. The expression level of PD-L1 was positively correlated with the abundance of CD8 + TILs (p < 0.0001). Furthermore, no constitutive expression of PD-L1 was observed in the majority of six NSCLC cell lines detected by Western blot; but exposure to interferon-γ (IFN-γ), a primary cytokine secreted by activated CD8+ T cells, prominently increased PD-L1 expression. Notably, a significantly positive association was determined within PD-L1, CD8 and IFN-γ gene expression by qRT-PCR, which was corroborated by RNA-sequencing from TCGA lung cancer dataset. These findings demonstrate that PD-L1 expression indicates an adaptive immune resistance mechanism adopted by tumor cells in the aversion of immunogenic destruction by CD8+ TILs. Both higher expression of PD-L1 and infiltration of CD8+ TILs were correlated with superior prognosis (p = 0.044 for PD-L1; p = 0.002 for CD8). Moreover, Cox multivariate regression analysis showed that the combination of PD-L1 and CD8 were independent prognostic factors, which was more accurate in prediction of prognosis in NSCLC than individually. Finally, we found that IFN-γ induced the upregulation of PD-L1 in NSCLC cells, mainly through the JAK/STAT1 signaling pathway. In conclusion, PD-L1 expression is mainly induced by activated CD8+ TILs via IFN-γ in the immune milieu and indicates pre-existing adaptive immune response in NSCLC. [ABSTRACT FROM AUTHOR]

Blockade of the immunosuppressive checkpoint receptors cytotoxic T-lymphocyte-associated protein 4 (CTLA4) or programmed death 1 (PD-1) and its cognate ligand, programmed death 1 ligand (PD-L1), has altered the landscape of anti-tumor immunotherapy. B7 family and tumor necrosis factor receptor (TNFR) superfamily play a crucial role in T cell activation, tolerance, and anergy through co-stimulatory and inhibitory signal transduction. Investigating the immune molecular landscapes of the B7 and TNFR families is critical in defining the promising responsive candidates. Herein, we performed comprehensive alteration analysis of the B7 and TNFR family genes across six hepatocellular carcinoma (HCC) datasets with over 1000 patients using cBioPortal TCGA data. About 16% of patients had both B7 and TNFR gene alterations. TNFR gene amplifications were relatively more common (1.73–8.82%) than B7 gene amplifications (1.61–2.94%). Analysis of 371 sequenced samples revealed that all genes were upregulated: B7 and TNFR mRNA were upregulated in 23% of cases (86/371) and 28% of cases (105/371), respectively. Promoter methylation analysis indicated an epigenetic basis for B7 and TNFR gene regulation. The mRNA levels of B7 and TNFR genes were inversely correlated with promoter methylation status. B7-H6 expression was significantly associated with worse overall survival, and B7-H6 mRNA was increased gradually in cases with gene copy number alterations. B7-H6 overexpression was associated with aggressive clinicopathologic features and poor prognosis in HCC. Downregulation of B7-H6 in HCC cells significantly inhibited cell adhesion, proliferation, migration, and invasion. Knockdown of B7-H6 in HCC cells inhibited tumor growth and metastasis in vivo. B7-H6 promoted HCC metastasis via induction of MMP-9 expression and STAT3 activation. B7-H6 and STAT3 performed functional overlapping roles on enhancing the MMP-9 promoter activity in HCC cells. These results suggest that alterations of the immunologic co-stimulator B7 and TNFR families correlate with HCC metastasis and prognosis, and especially B7-H6 plays a critical role in promoting metastasis of HCC. [ABSTRACT FROM AUTHOR]

In this paper, the effect of ultraviolet light on the [CuL](ClO4)2–glucose (Glu)–acetone (Act)–sodium bromate (NaBrO3)–sulfuric acid (H2SO4) oscillation system was studied. The reaction mechanism and Oregonator model were established to verify the mechanism. Comparison of the bromide ion electrode–platinum electrode correlation diagrams with and without ultraviolet light reveals a nontracking phenomenon in the bromide ion electrode–platinum electrode correlation diagram under illumination, indicating that the illumination will affect the changes in the bromide ion concentration in the system. During the process, as UV intensity increases, the concentration of bromide ions in the system increases, and bromide ions can inhibit chemical oscillations, resulting in a decrease in the amplitude of chemical oscillations, further verifying that the proposed mechanism is reasonable. [ABSTRACT FROM AUTHOR]

D-dot sensors meet the development trend towards the downsizing, automation and digitalization of voltage sensors and is one of research hotspots for new voltage sensors at present. The traditional voltage measurement system of D-dot sensors makes possible the reverse solving of wire potentials according to the computational principles of the electric field inverse problem by measuring electric field values beneath the transmission line. Nevertheless, as it is limited by the solving method of the electric field inverse problem, the D-dot sensor voltage measurement system is struggling with solving difficulties and poor accuracy. To solve these problems, this paper suggests introducing a Gaussian integral into the D-dot sensor voltage measurement system to accurately measure the voltage of transmission lines. Based on studies of D-dot sensors, a transmission line voltage measurement method based on Gaussian integrals is proposed and used for the simulation of the electric field of a 220 kV and a 20 kV transmission line. The feasibility of the introduction of the Gaussian integral to solve transmission line voltage was verified by the simulation results. Finally, the performance of the Gaussian integral was verified by an experiment using the transmission line voltage measurement platform. The experimental results demonstrated that the D-dot sensor measurement system based on a Gaussian integral achieves high accuracy and the relative error is lower than 0.5%. [ABSTRACT FROM AUTHOR]

Aberrant expression of programmed death ligand 1 (PD-L1) on tumor cells impedes antitumor immunity and instigates immune evasion. The remarkable efficacy of immune checkpoint blockade has been confirmed in various solid tumors. However, the correlation between PD-L1 expression and host immunological landscape remains of considerable controversy in non-small cell lung cancer (NSCLC). In the present study, PD-L1 expression and CD8 + tumor-infiltrating lymphocyte (TIL) infiltration levels were determined by immunohistochemistry (IHC) in tumor sections of 138 NSCLC patients. The expression level of PD-L1 was positively correlated with the abundance of CD8 + TILs ( p < 0.0001). Furthermore, no constitutive expression of PD-L1 was observed in the majority of six NSCLC cell lines detected by Western blot; but exposure to interferon-γ (IFN-γ), a primary cytokine secreted by activated CD8 + T cells, prominently increased PD-L1 expression. Notably, a significantly positive association was determined within PD-L1, CD8 and IFN-γ gene expression by qRT-PCR, which was corroborated by RNA-sequencing from TCGA lung cancer dataset. These findings demonstrate that PD-L1 expression indicates an adaptive immune resistance mechanism adopted by tumor cells in the aversion of immunogenic destruction by CD8 + TILs. Both higher expression of PD-L1 and infiltration of CD8 + TILs were correlated with superior prognosis ( p = 0.044 for PD-L1; p = 0.002 for CD8). Moreover, Cox multivariate regression analysis showed that the combination of PD-L1 and CD8 were independent prognostic factors, which was more accurate in prediction of prognosis in NSCLC than individually. Finally, we found that IFN-γ induced the upregulation of PD-L1 in NSCLC cells, mainly through the JAK/STAT1 signaling pathway. In conclusion, PD-L1 expression is mainly induced by activated CD8 + TILs via IFN-γ in the immune milieu and indicates pre-existing adaptive immune response in NSCLC.

Environmentally friendly handling and efficient recycling of waste electrical on Waste Electrical and Electronic Equipment (WEEE) have grown to be a global social problem. As holders of WEEE, consumers have a significant effect on the recycling process. A consideration of and attention to the influence of consumer behavior in the recycling process can help achieve more effective recycling of WEEE. In this paper, we built a dual-channel closed-loop supply chain model composed of manufacturers, retailers, and network recycling platforms. Based on the influence of customer bargaining behavior, we studied several different scenarios of centralized decision-making, decentralized decision-making, and contract coordination, using the Stackelberg game theory. The results show that retailers and network recycling platforms will reduce the direct recovery prices to maintain their own profit when considering the impact of consumer bargaining behavior, while remanufacturers will improve the transfer payment price for surrendering part of the profit under revenue and the expense sharing contract. Using this contract, we can achieve supply chain coordination and eliminate the effect of consumer bargaining behavior on supply chain performance. It can be viewed from the parameter sensitivity analysis that when we select the appropriate sharing coefficient, the closed-loop supply chain can achieve the same system performance under a centralized decision., Competing Interests: The authors declare no conflict of interest.

S100A12 is involved in the inflammatory response and is considered an important marker for many inflammatory diseases in humans. Our previous studies indicated that the S100A12 gene was abundant in the immune tissues of pigs and was significantly upregulated during infection with Haemophilus parasuis (HPS) or porcine circovirus type 2 (PCV2). In this study, the mechanism of transcriptional regulation of S100A12 was investigated in pigs. Our results showed that S100A12, CCAAT/enhancer-binding protein beta (C/EBPβ) and activator protein-1 (AP-1) genes were up-regulated in PK-15 (ATCC, CCL-33) cells when treated with LPS or Poly I: C. Additionally, the promoter activity and expression level of the S100A12 gene were significantly upregulated when C/EBPβ or AP-1 were overexpressed. We utilized electromobility shift assays (EMSA) to confirm that C/EBPβ and AP-1 could directly bind the S100A12 gene promoter. We also found that the transcriptional activity and expression levels of C/EBPβ and AP-1 could positively regulate each other. Furthermore, the promoter activity of the S100A12 gene was higher when C/EBPβ and AP-1 were cotransfected than when they were transfected individually. We concluded that the S100A12 gene was cooperatively and positively regulated by C/EBPβ and AP-1 in pigs. Our study offers new insight into the transcriptional regulation of the S100A12 gene.