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A homogeneous polysaccharide named as LJW2F2 was extracted and purified from the flowers of Lonicera japonica Thunb. Structural characteristic indicated that LJW2F2 was a homogalacturonan composed of α-1,4-D-galacturonic acid with a molecular weight of 7.2 kDa. Previous investigation suggested that homogalacturonan might impede angiogenesis, however the mechanism is still vague. Here we reported that LJW2F2 significantly disrupted capillary-like tube formation of human microvascular endothelia cells (HMEC-1) on matrigel as well as the cells migration. Mechanism study revealed that LJW2F2 might inactivate phosphorylation of epidermal growth factor receptor (EGFR), subsequently suppress Raf, mitogen-activated protein kinase (MEK) and extracellular-related kinase (ERK) phosphorylation. Moreover, LJW2F2 markedly decreased the expression of Notch1 and Delta-like ligand 4 (Dll4). Therefore, our results suggested that LJW2F2 might be a potential angiogenesis inhibitor via disturbing multiple signaling pathways.

Magnesium is considered to play a role in preventing cancer. However, the association between serum magnesium and papillary thyroid cancer (PTC) remains unknown. We retrospectively reviewed records of all patients who underwent thyroidectomy with thyroid nodules confirmed pathologically as benign nodule or PTC at our institution from January 2016 to December 2020. Data including demographic characteristics, laboratory tests, and pathological features were analyzed in 5709 adult patients eventually. The subjects with benign nodules had a higher mean serum magnesium level than those with PTC (P 0.001), and the proportions of PTCs decreased across quartiles of serum magnesium within the normal range. After adjustment for confounders, patients with the lowest quartile of serum magnesium had a higher prevalence of PTC than those with the highest quartile (OR = 1.421, 95%CI: 1.125-1.795, P for trend = 0.005), and the risk of PTC was 0.863 (95%CI: 0.795-0.936) for a per-SD change in serum magnesium. The contribution of serum magnesium remained in subgroup analysis (P for interaction for all analyses 0.05). Based on the ROC curve, the cut-off value of serum magnesium used to differentiate benign nodules from PTCs was 935 μmol/L. Combining serum magnesium with other clinical indicators can improve the efficacy of predicting PTC. Our results showed that lower serum magnesium within the normal range was associated with a greater risk of PTC among patients with thyroid nodules considering thyroidectomy. Serum magnesium may be an independent protective factor against PTC and provide additional information on the odds of malignancy in uncertain thyroid nodules in combination with other clinical factors.

Atomic thickness thin films are critical functional materials and structures in atomic and close-to-atomic scale manufacturing. However, fast, facile, and highly sensitive precision measurement of atomic film thickness remains challenging. The reflected light has a dramatic phase change and extreme reflectivity considering the Brewster angle, indicating the high sensitivity of the optical signal to film thickness near this angle. Hence, the precision polarization measurement method focusing on Brewster angle is vital for the ultrahigh precision characterization of thin films. A precision polarization measurement method based on a liquid crystal variable retarder (LCVR) is proposed in this paper, and a measurement system with a high angular resolution is established. A comprehensive measurement system calibration scheme is also introduced to accommodate ultrahigh precision film thickness measurement. Repeatable measurement accuracy to the subnanometer level is achieved. Standard silicon oxide film samples of different thicknesses were measured around Brewster angle using the self-developed system and compared with a commercial ellipsometer to verify the measurement accuracy. The consistency of the thickness measurement results demonstrates the feasibility and robustness of the measurement method and calibration scheme. This study also demonstrates the remarkable potential of the LCVR-based polarization method for atomic film thickness measurement in ultraprecision manufacturing.

The cultivation mode of planting offseason crops, such as cucumber, with drip irrigation has been widely used in greenhouses in North China to achieve high yields, obtain large economic benefits, and improve water use efficiency. The objectives of this study were to evaluate the effects of drip irrigation on the irrigation water amount, irrigation water use efficiency (IWUE), and cucumber yield and the corresponding economic benefits. These objectives were achieved using data from a seven-season experiment in a commercial greenhouse with cucumber plants in North China. Local furrow irrigation was used as the control. The results showed that the cucumber yields and income with drip irrigation were 4.3% and 3.1% higher than those under furrow irrigation, respectively. However, the seasonal total irrigation depth for drip irrigation was approximately 50% lower than that for furrow irrigation. The IWUE averaged 0.41 in furrow irrigation but increased to 0.79 in drip irrigation. The irrigation water productivity and the economic irrigation water productivity for drip irrigation were approximately 100% higher than those for furrow irrigation. The mean economic irrigation water productivity was 19.8 US$ m−3 for drip irrigation, which is 7 times higher than the 2019 value of 2.7 US$ m−3 in the agricultural sector in China, indicating potential high economic benefits. In conclusion, drip irrigation is recommended in greenhouses to reduce irrigation water by approximately 50% and increase cucumber yield and economic benefits by approximately 3–4% compared to traditional furrow irrigation in North China.

The process of lubricant penetration into frictional interfaces has not been fully established, hence compromising their tribological performance. In this study, the penetration characteristics of deionized water (DI water) containing an electroosmotic suppressant (cetyltrimethylammonium bromide (CTAB)) and an electroosmotic promoter (sodium lauriminodipropionate (SLI)), were investigated using steel-on-steel friction pairs. The results indicated that the lubricant with electroosmotic promoter reduced the coefficient of friction and wear scar diameter, whereas that with an electroosmotic suppressant exhibited an opposite behavior compared with DI water. The addition of SLI promoted the penetration of the DI water solution, thus resulting in the formation of a thick lubricating film of iron oxide at the sliding surface. This effectively reduced the abrasion damage, leading to a lower coefficient of friction and wear loss.

Flash memories and semiconductor p-n junctions are two elementary but incompatible building blocks of most electronic and optoelectronic devices. The pressing demand to efficiently transfer massive data between memories and logic circuits, as well as for high data storage capability and device integration density, has fueled the rapid growth of technique and material innovations. Two-dimensional (2D) materials are considered as one of the most promising candidates to solve this challenge. However, a key aspect for 2D materials to build functional devices requires effective and accurate control of the carrier polarity, concentration and spatial distribution in the atomically thin structures. Here, a non-volatile opto-electrical doping approach is demonstrated, which enables reversibly writing spatially resolved doping patterns in the MoTe2 conductance channel through a MoTe2/hexagonal boron nitride (h-BN) heterostructure. Based on the doping effect induced by the combination of electrostatic modulation and ultraviolet light illumination, a 3-bit flash memory and various homojunctions on the same MoTe2/BN heterostructure are successfully developed. The flash memory achieved 8 well distinguished memory states with a maximum on/off ratio over 104. Each state showed negligible decay during the retention time of 2,400 s. The heterostructure also allowed the formation of p-p, n-n, p-n, and n-p homojunctions and the free transition among these states. The MoTe2 p-n homojunction with a rectification ratio of 103 exhibited excellent photodetection and photovoltaic performance. Having the memory device and p-n junction built on the same structure makes it possible to bring memory and computational circuit on the same chip, one step further to realize near-memory computing.

This paper establishes several sufficient conditions for the weak Pareto optimality of Nash equilibria in nonatomic routing games on single- and multi-commodity networks, where a Nash equilibrium (NE) is weakly Pareto optimal (WPO) if under it no deviation of all players could make everybody better off. The results provide theoretical and technical bases for characterizing graphical structures for nonatomic routing games to admit WPO NEs. We prove that the NE of every nonatomic routing game on a single or multi-commodity network is WPO (regardless of the choices of nonnegative, continuous, nondecreasing latency functions on network links) if the network does not have two links x, y and three paths each of which goes from some origin to some destination such that the intersections of the three paths with $$\{x,y\}$$ are $$\{x\},\{y\}$$ and $$\{x,y\}$$, respectively. This sufficient condition leads to an alternative proof of the recent result that the NE of every 2-commodity nonatomic routing game on any undirected cycle is WPO. We verify a general property satisfied by all feasible 2-commodity routings (not necessarily controlled by selfish players) on undirected cycles, which roughly says that no feasible routing can “dominate” another in some sense. The property is crucial for proving the weak Pareto optimality associated to the building blocks of undirected graphs on which all NEs w.r.t. two commodities are WPO.

Background Patrinia scabra Bunge is a well-known herbal medicine for its favorable treatment on inflammatory diseases owing to its effective ingredients, in which iridoid glycoside plays an extremely significant role. This article aimed to improve the content of total iridoid glycosides in crude extract through a series optimization of extraction procedure. Moreover, considering that both pain and inflammation are two correlated responses triggered in response to injury, irritants or pathogen, the article investigated the anti-inflammatory and analgesic activities of P. scabra to screen out the active fraction. Method P. scabra was extracted by ultrasonic-microwave synergistic extraction (UMSE) to obtain total iridoid glycosides (PSI), during which a series of conditions were investigated based on single-factor experiments. The extraction process was further optimized by a reliable statistical method of response surface methodology (RSM). The elution fractions of P. scabra extract were prepared by macroporous resin column chromatography. Through the various animal experiment including acetic acid-induced writhing test, formalin induced licking and flinching, carrageenan-induced mice paw oedema test and xylene-induced ear edema in mice, the active fractions with favorable analgesic and anti-inflammatory effect were reasonably screen out. Results The content of PSI could reach up to 81.42 ± 0.31 mg/g under the optimum conditions as follows: ethanol concentration of 52%, material-to-liquid ratio of 1:18 g/mL, microwave power at 610 W and extraction time of 45 min. After gradient elution by the macroporous resin, the content of PSI increased significantly. Compared with other concentrations of elution liquid, the content of PSI in 30 and 50% ethanol eluate was increased to reach 497.65 and 506.90 mg/g, respectively. Owing to the pharmacology experiment, it was reasonably revealed that 30 and 50% ethanol elution fractions of P. scabra could relieve pain centrally and peripherally, exhibiting good analgesic and anti-inflammatory activities. Conclusion Patrinia scabra possessed rich iridoids and exhibited significant analgesic and anti-inflammatory activities.

Magnetic seizure therapy (MST) has established efficacy in the treatment of depression and a growing evidence base in the treatment of depression. We conducted the first systematic review and meta-analysis of the efficacy of MST in anti-depressive treatment and its impact on cognitive function (INPLASY registration number: INPLASY202170061). We searched for controlled trials published in English between 1 January 2001 to 31 December 2020 in PubMed, EMBASE, Cochrane Library, Web of Science, and PsycINFO databases. The evaluation process strictly followed the Cochrane bias risk assessment tool into the literature, and Meta-analysis was performed according to the Cochrane System Reviewer’s Manual. Data from a total of 285 patients from 10 studies were retained in the quantitative synthesis. The results showed no significant difference between MST and ECT in the antidepressant effect (SDM −0.13 [−0.78;0.52]). Compared with ECT, MST showed shorter recovery time (MD −5.67 [−9.75; −1.60]) and reorientation time (MD −14.67 [−27.96; −1.41]); and MST showed less cognitive impairment on the immediate recall of words (SDM 0.80 [0.35;1.25]), delayed recall of words (SDM 0.99 [0.01;0.74]), visual-spatial immediate memory (SDM 0.51 [0.20;0.83]), visual-spatial delayed memory (SDM 0.57 [0.11;1.02]), and the verbal fluency (SDM 0.51 [0.20;0.83]). Our evidence-based study is the first meta-analysis on the efficacy of MST in anti-depressive treatment and its effect on cognitive function. It showed that the curative effect of MST in anti-depressive treatment is equivalent to that of ECT. Besides, depressive patients with MST benefit more from cognitive function compared with ECT.

The occurrence, seasonal variation and emission of nine widely used phosphorus flame retardants (PFRs) were investigated in a wastewater treatment plant (WWTP) located in Guangzhou, China, over 1 year. Results showed that PFRs were widely detected in wastewater and sewage sludge. Tris(2-chloroisopropyl) phosphate (TCIPP) was the most dominant PFRs in influent, effluent, and sludge. Significant seasonal variation of total PFRs in the influent was observed (p

Prevailing tissue degeneration caused by musculoskeletal maladies poses a great demand on bioscaffolds, which are artificial, biocompatible structures implanted into human bodies with appropriate mechanical properties. Recent advances in additive manufacturing, i.e., 3D printing, facilitated the fabrication of bioscaffolds with unprecedented geometrical complexity and size flexibility and allowed for the fabrication of topologies that would not have been achieved otherwise. In our work, we explored the effect of porosity on the mechanical properties of a periodic cellular structure. The structure was derived from the mathematically created triply periodic minimal surface (TPMS), namely the Sheet-Diamond topology. First, we employed a series of software including MathMod, Meshmixer, Netfabb and Cura to design the model. Then, we utilized additive manufacturing technology to fabricate the cellular structures with designated scale. Finally, we performed compressive testing to deduce the mechanical properties of each cellular structure. Results showed that, in comparison with the high-porosity group, the yield strength of the low-porosity group was 3 times higher, and the modulus was 2.5 times larger. Our experiments revealed a specific relationship between porosity and Young’s modulus of PLA-made Sheet-Diamond TPMS structure. Moreover, it was observed that the high- and low-porosity structures failed through distinctive mechanisms, with the former breaking down via buckling and the latter via micro-fracturing.

Accumulating studies have shown that long noncoding RNAs (lncRNAs) are involved in cancer occurrence and development. Recently a new lncRNA LINC00460 has been reported to be upregulated in several types of cancers. In this study, we investigated the role of LINC00460 in invasion and metastasis of nasopharyngeal carcinoma (NPC). In NPC cell lines named C666-1 and 5-8F, LINC00460 overexpression promoted cancer cell migration, invasion and epithelial-mesenchymal transition (EMT), while depletion of LINC00460 exhibited opposite effects. We further demonstrated that LINC00460 regulated Rap1A expression through competitively binding to miR-30a-3p. LINC00460 knockdown suppressed NPC metastasis in a xenograft mouse model. Taken together, our findings suggested LINC00460 functioned as an oncogene in NPC which promoted invasion and metastasis, shedding lights on LINC00460 as a potential therapeutic target for NPC therapeutics from bench to clinic.

Inefficient sample preparation methods hinder the performance of high-throughput single-molecule force spectroscopy (H-SMFS) for viscous damping among reactants and unstable linkage. Here, we demonstrated a sample preparation method for H-SMFS systems to achieve a higher ratio of effective target molecules per sample cell by gas-phase silanization and reactant hydrophobization. Digital holographic centrifugal force microscopy (DH-CFM) was used to verify its performance. The experimental result indicated that the DNA stretching success ratio was improved from 0.89% to 13.5%. This enhanced efficiency preparation method has potential application for force-based DNA stretching experiments and other modifying procedures.

Here, we prepared nano-SiO2-coated graphite films using a novel laser-assisted sol–gel method. The SiO2 sol–gel prepositioned on the graphite substrate was irradiated by the fiber laser at different energy densities. The growth mechanism of the coatings under laser irradiation was studied and the effects of processing parameters on the coating structure were systematically investigated. In addition, the high-temperature oxidation resistance of these samples was examined. Surface morphology and elemental composition were examined using scanning electron microscopy and energy-dispersive spectrometer. Phase constituents and microstructure were identified by x-ray diffraction and transmission electron microscopy. The oxidation resistance was analyzed by thermal gravimetric analysis. The results found that laser irradiation significantly modifies the sol–gel-deposited nano-SiO2 layer. A uniform and compact nano-SiO2 coating was obtained when irradiated by laser energy density of 14.4 kJ/cm2. Optimum high-temperature oxidation resistance was achieved for the two-layer SiO2-coated films.

A green manufacturing technology named “electrostatic minimum quantity lubrication (EMQL)” with water-based Al2O3 nanoparticle fluids as cutting fluids was developed in order to improve the cutting property and minimize oil mist concentration during the machining process. The capillary penetration mechanism, oil mist concentration, and heat transfer property of Al2O3 fluid EMQL were investigated. The cutting performance of Al2O3 fluid EMQL and traditional minimum quantity lubrication (MQL) was compared. The results showed that EMQL could improve the penetrability and heat transfer capacity of the lubricant effectively. Compared with Al2O3 fluid MQL and oil-based MQL, Al2O3 fluid EMQL reduced oil mist concentration and cutting temperature remarkably and showed similar cutting performances compared with the oil-based MQL. The excellent performance of this water-based Al2O3 fluid EMQL technology was mainly due to that EMQL could promote a further penetration of the charged Al2O3 nanofluid droplets into the cutting region, which thus reduced the friction force, and the tool durability was maintained obviously and finally presented better machining performance.

We address the metric ring star problem with fixed edge-cost ratio, abbreviated as RSP. Given a complete graph $$G=(V,E)$$ with a specified depot node $$d\in V$$ , a nonnegative cost function $$c\in \mathbb {R}_+^E$$ on E which satisfies the triangle inequality, and an edge-cost ratio $$M\ge 1$$ , the RSP is to locate a ring $$R=(V',E')$$ in G, a simple cycle through d or d itself, aiming to minimize the sum of two costs: the cost for constructing ring R, i.e., $$M\cdot \sum _{e\in E'}c(e)$$ , and the cost for attaching nodes in $$V{\setminus } V'$$ to their closest ring nodes (in R), i.e., $$\sum _{u\in V{\setminus } V'}\min _{v\in V'}c(uv)$$ . We show that the singleton ring d is an optimal solution of the RSP when $$M\ge (|V|-1)/2$$ . This particularly implies a $$\sqrt{|V|-1}$$ -approximation algorithm for the RSP with any $$M\ge 1$$ . We present randomized 3-approximation algorithm and deterministic 5.06-approximation algorithm for the RSP, by adapting algorithms for the tour-connected facility location problem (tour-CFLP) and single-source rent-or-buy problem due to Eisenbrand et al. and Williamson and van Zuylen, respectively. Building on the PTAS of Eisenbrand et al. for the tour-CFLP, we give a PTAS for the RSP with $$|V|/M=O(1)$$ . We also consider the capacitated RSP (CRSP) which puts an upper limit k on the number of leaf nodes that a ring node can serve, and present a $$(10+6M/k)$$ -approximation algorithm for this capacitated generalization. Heuristics based on some natural strategies are proposed for both the RSP and CRSP. Simulation results demonstrate that the proposed approximation and heuristic algorithms have good practical performances.

As a typical representative of green lubrication/cooling mode, minimum quantity lubrication (MQL) is widely recognized by the industry for its excellent machining performance. However, the oil mist generated from oil-based MQL machining process has a direct impact on the ambient air quantity and then does harm those who permanently work in this environment. To alleviate this defect, a novel lubrication strategy named magnetic minimum quantity lubrication (mMQL) allocated with water-based Fe3O4 nanofluid as cutting fluid was proposed. The effect of different magnetic induction on the kinetic viscosity and atomization performance of water-based Fe3O4 nanofluid was investigated. The deposition property of water-based Fe3O4 nanofluid droplets produced by mMQL and LB-2000 vegetable oil droplets produced by MQL were compared, and the corresponding oil mist concentrations (PM10, PM2.5) were also measured. Eventually, the machining performances of water-based Fe3O4 nanofluid mMQL and LB-2000 vegetable oil MQL applied in milling of 430 stainless steel were compared. Results exhibited that water-based Fe3O4 nanofluid presented higher kinetic viscosity and larger droplet size under higher magnetic induction intensity. Water-based Fe3O4 nanofluid mMQL with magnetic induction intensity of 60–100 mT displayed lower PM10 and PM2.5 concentrations, tool flank wear value, milling force, and surface roughness value in comparison with LB-2000 vegetable oil applied in MQL. This water-based Fe3O4 nanofluid used in mMQL showed higher kinetic viscosity and atomized larger droplet-size and thus presented further deposition quantity, which demonstrated alternative cutting performance and lessened the oil mist particles floating in the operating environment.

Thermal spallation may be economically advantageous for the drilling of deep wells and is of strong interest for the development of oil, gas and geothermal energy. The lowest required surface temperature (LRST) represents the minimal surface temperature that can induce the spallation of rock. A deeper understanding of the LRST can be used to determine when thermal spallation can be successfully initiated. However, to the best of our knowledge, comparisons of LRST in sandstone and granite have not been performed. Based on experiments and simulations, this study investigated the LRST of one type of granite and one type of sandstone in thermal spallation. First, we conducted thermal spallation experiments using rock specimens and measured the LRST by an infrared thermometer. Then, the heat flux was evaluated and compared between the sandstone and granite specimens. Meanwhile, a three-dimensional numerical model was built to simulate the heat transfer and stress distribution in the granite and sandstone specimens. The temperature and von Mises stress between the granite and sandstone specimens were compared, and then the breakage-probability factors were investigated to compare the experimental results and simulation results. This study clarifies the differences in LRST between one type of granite and one type of sandstone.

This paper provides an x-ray scatter correction method for cone beam computed tomography (CT) to reduce cupping artifacts and image inhomogeneity of metal additive manufacturing (AM) components. Firstly, projections in 360° were obtained by a cone beam CT system. Secondly, the corresponding virtual CT system was built on Geant4 to obtain scatter photons. Different from previous studies, the geometry of the metal AM component was set by importing a CAD model of the component into Geant4, which can not only assure the accuracy of geometry but also simplify the definition of the geometry. Finally, the corresponding scatter photons were subtracted from the experimental projections in 360° to obtain corrected projections. Corrected reconstruction images were acquired via an FDK algorithm. In the corrected images, the average sum of squares of deviation of regions of interest was about 79.5% of that in the uncorrected images. Corrected images showed that cupping-shaped artifacts and image inhomogeneity were effectively reduced.

Geographical thematic mapping based on spatial information can effectively support scientific decision-making in Geosciences. To obtain finer spatial decision information, this paper proposes a geo-parcel-based thematic mapping methodology for evaluating cash crop planting suitability using C5.0 decision tree (DT). In this study, geo-parcels are utilized as basic mapping units. Multi-source data are firstly employed to increase geo-parcel units’ attributes and a decision table then is constructed under a multi-attribute index system. Next, rules are mined using a C5.0 DT algorithm according to local geo-parcels in this decision table. Finally, rules are referred as thematic-distinguishing knowledge for inferential mapping in global geo-parcels. A case study of sugarcane planting suitability evaluation is conduct based on the proposed methodology. The experimental results showed that the cross-validation accuracy of the rules is 81.34% and the sum of the very suitable area and suitable area in the generated evaluation map is close to that of historical selected high-yield and high-sugar-content sugarcane bases, which indicated that the mapping result is in good agreement with the actual selection situation. These also demonstrate the effectiveness of our method and thus may be extended to other domains requiring fine geographical thematic mapping of cash crop planting suitability.

In high-resolution remote sensing image processing, segmentation is a crucial step that extracts information within the object-based image analysis framework. Because of its robustness, mean-shift segmentation algorithms are widely used in the field of image segmentation. However, the traditional implementation of these methods cannot process large volumes of images rapidly under limited computing resources. Currently, parallel computing models are generally employed for segmentation tasks with massive remote sensing images. This paper presents a parallel implementation of the mean-shift segmentation algorithm based on an analysis of the principle and characteristics of this technique. To avoid the inconsistency on the boundaries of adjacent data chunks, we propose a novel buffer-zone-based data-partitioning strategy. Employing the proposed data-partitioning strategy, two intensively computation steps are performed in parallel on different data chunks. The experimental results show that the proposed algorithm effectively improves the computing efficiency of image segmentation in a parallel computing environment. Furthermore, they demonstrate the practicality of massive image segmentation when computer resources are limited.

Let G = (V, E) be a simple graph and $\mathbf {w}\in \mathbb {Z}^{E}_{>0}$ assign each edge e ∈ E a positive integer weight w(e). A subset of E that intersects every triangle of G is called a triangle cover of (G, w), and its weight is the total weight of its edges. A collection of triangles in G (repetition allowed) is called a triangle packing of (G, w) if each edge e ∈ E appears in at most w(e) members of the collection. Let τ t (G, w) and ν t (G, w) denote the minimum weight of a triangle cover and the maximum cardinality of a triangle packing of (G, w), respectively. Generalizing Tuza’s conjecture for unit weight, Chapuy et al. conjectured that τ t (G, w)/ν t (G, w) ≤ 2 holds for every simple graph G and every $\mathbf {w}\in \mathbb {Z}^{E}_{>0}$ . In this paper, using a hypergraph approach, we design polynomial-time combinatorial algorithms for finding triangle covers of small weights. These algorithms imply new sufficient conditions for the conjecture of Chapuy et al. More precisely, given (G, w), suppose that all edges of G are covered by the set ${\mathscr {T}}_{G}$ consisting of edge sets of triangles in G. Let $|E|_{w}={\sum }_{e\in E}w(e)$ and $|{\mathscr {T}}_{G}|_{w}={\sum }_{\{e,f,g\}\in {\mathscr {T}}_{G}}w(e)w(f)w(g)$ denote the weighted numbers of edges and triangles in (G, w), respectively. We show that a triangle cover of (G, w) of weight at most 2ν t (G, w) can be found in strongly polynomial time if one of the following conditions is satisfied: (i) $\nu _{t}(G,\mathbf {w})/|{\mathscr {T}}_{G}|_{w}\ge \frac {1}{3}$ , (ii) $\nu _{t}(G,\mathbf {w})/|E|_{w}\ge \frac {1}{4}$ , (iii) $|E|_{w}/|{\mathscr {T}}_{G}|_{w}\ge 2$ .

Minimum quantity lubrication (MQL) technologies using vegetable oil lubricants as cutting fluids have attracted much attention as they have excellent machining performance and are environmentally friendly. Nevertheless, oil-based MQL tends to produce high cutting temperatures owning to the low cooling capability of oil lubricants. In this work, an MQL technology that utilizes graphene oxide/silicon dioxide (GO/SiO2) hybrid nanoparticle water-based lubricants as cutting fluids was developed, and its tribological and machining characteristics were comparatively investigated using four-ball and milling testing units. The mass ratio of GO to SiO2 was also varied to achieve optimal performance. The results showed that GO/SiO2 water-based MQL reduced coefficient of friction (COF) and worn scar diameter (WSD) significantly, and improved machining performance compared with individual GO and SiO2 water-based MQLs, as well as showed a comparative performance with traditional vegetable oil-based MQL. The superior performance of GO/SiO2 water-based MQL was attributed to the fact that GO/SiO2 hybrid nanoparticle additives entered the rubbing interface and formed a composite protecting film consisting of a self-lubrication layer of GO and a tribo-thin layer of SiO2, which prevented the interface from direct contact and smoothened asperities.

Recognizing capture position for non-cooperative targets is an important component of on-orbit service. Traditional machine learning works could not satisfy the requirements of space mission, which demands universality, accuracy and real-time performance. To meet those requirements, an innovative job based on deep learning called Faster Region-based Convolutional Neural Network (Faster RCNN) is introduced for space robot capture position recognizing. Based on the principle of similar training, a minimal dataset construction trick is proposed in order to solve the problem of fewer training samples in space environment. Firstly, the Deep Neural Network is pre-trained through ImageNet training set. Then, using the trained weights as the initial weight of the network, the network is fine-tuned by 1000 training samples in space environment. Finally, a simulation experiment is designed, and the experimental results indicate that the similar training principle can solve the problem of capture position recognition of non-cooperative targets.

PURPOSE: The purpose of this study was to determine the heterotopic pregnancy rate using fresh versus frozen-thawed embryo transfers and factors associated with heterotopic pregnancy (HP). Management and clinical outcomes after heterotopic pregnancy were also evaluated. METHODS: In this retrospective cohort study, we included 12,484 women who had clinical pregnancies after in vitro fertilization treatment at our fertility center between 2012 and 2017. Patients received fresh day 3 embryos (F-D3 group), fresh day 5 blastocysts (F-D5 group), frozen-thawed day 3 embryos (T-D3 group), or frozen-thawed day 5 or 6 blastocysts (T-D5/6 groups) transfers. The primary outcome measure was the occurrence of heterotopic pregnancy. Factors associated with heterotopic pregnancy were analyzed using logistic regression. RESULTS: The heterotopic pregnancy rates were 0.58% in the F-D3, 0.39% in F-D5, 0.56% in T-D3, and 0.33% in T-D5/6 groups, but no differences were found between groups. The risk factors of HP included a history of previous ectopic pregnancy (odds ratio [OR] 5.805, 95% CI 4.578–9.553, P = 0.016) and pelvic inflammation diseases (OR 1.129, 95% CI 1.021–3.178, P = 0.047). Salpingectomy was performed in 62.9% patients either through laparoscopy or through laparotomy. The early abortion rate and late abortion rate were 29.03% and 1.61%, respectively. In total, 66.13% of the patients had a live birth, either a singleton (90.24%) or twins (9.76%). CONCLUSION: No significant difference in the incidence of heterotopic pregnancy in fresh IVF cycles vs. frozen-thawed cycles could be demonstrated in a large cohort of patients. The risk factors of HP included history of ectopic pregnancy and PID. The clinical outcome after heterotopic pregnancy appears to be favorable.

High-quality GaN micro/nano columns were prepared with self-organized catalytic-free method. Young’s modulus of GaN nanocolumns were measured under both compressive stress and tensile stress. It was found that the Young’s modulus decreases with the increasing of nanocolumn diameter due to the increase of face defect density. Furthermore, we measured the piezoelectric properties and found that there was a 1000-fold current increase under a strain of 1% with a fixed bias voltage of 10 mV. Based on the Schottky Barrier Diode model, we modified it with the effect of polarization charge, image charge and interface state to analyze the experiment results which reveals that the strong piezopolarization effect plays an important role in this phenomenon. Therefore, the GaN nanocolumns has a great prospect to be applied in high-efficiency nanogenerators and high-sensitivity nanosensors.

Braess's paradox exposes a counterintuitive phenomenon that when travelers selfishly choose their routes in a network, removing links can improve the overall network performance. Under the model of nonatomic selfish routing, we characterize the topologies of k-commodity undirected and directed networks in which Braess's paradox never occurs. Our results strengthen Milchtaich's series-parallel characterization (Milchtaich, Games Econom. Behav. 57(2), 321---346 (2006)) for the single-commodity undirected case.

Recombinant SjCystatin (rSjCystatin), a recombinant protein of Schistosoma japonicum cystatin, has been reported to have an effect on immunoregulation mediated by IL-10 induction. Rheumatoid arthritis (RA) is a common autoimmune inflammatory arthropathy, and recombinant immune-modulating drugs for RA treatment are under development. We aimed to study the putative immune regulation of rSjCystatin and its prophylactic/therapeutic effects on murine collagen-induced arthritis (CIA). CIA was induced in DBA/1 mice by inoculation with bovine collagen II (CII). rSjCystatin was administered prior or post development of CIA. The severity of CIA was assessed using established clinical and histopathological scoring systems. The incidence was also determined. The CII-specific antibodies in sera and cytokines in splenocyte culture supernatants were measured by ELISA. Th1/Th2/Th17 cells and Tregs development in splenocytes were monitored by flow cytometry. The inflammatory mediators in the diseased joint were semiquantitated by qPCR. Prophylactic injection of rSjCystatin attenuated paw clinical scores, incidence, and histopathology scores of joints in CIA mice. The arthritis-alleviative effects were closely associated with the augmentation of IL-4, IL-10, and collagen-specific IgG1, and with the distinct reduction of IFN-γ, collagen-specific IgG2a, and the marked decrease of proinflammatory cytokines IL-6, IL-17, and TNF-α and RANKL. The data indicate that rSjCystatin may prevent cartilage destruction and inflammation of joints in CIA mice. The effects are related to the inhibitory modulation of Th1 and Th17 and upregulation of Tregs and Th2 via a shift of cytokines profiling from Th1 to Th2 response.

Six MnIII(porphyrin)-based porous coordination polymers, MnIII(F5CPp)–MnII (CP1, F5CPp=5-(pentafluorophenyl)-10,15,20-tri(4-carboxyphenyl)porphyrin dianion), MnIII(F5CPp)–CoII (CP2), MnIII(F5CPp)–NiII (CP3), MnIII(F10CPp)–MnII (CP4, F10CPp=5,15-bis(pentafluorophenyl)-10,20-bis(4-carboxyphenyl)porphyrin dianion), MnIII(F10CPp)–CoII (CP5), and MnIII(F10CPp)–NiII (CP6), were prepared and characterized. The precursors were identified by UV–Vis, GC–MS, infrared spectra and elemental analysis in the procedures of MnIII(porphyrin)-based polymers synthesis. CP1, CP4, CP3 and CP6 are amorphous aggregation supported by SEM, TEM and powder XRD. CP2 and CP5 are rod-like microcrystalline particles supported by powder XRD and SAED. These polymers exhibit high catalytic activities and selectivities toward the oxidation of ethylbenzene to acetophenone in quantitative over 70 % yields, and can be reused by filtration with only slight decreasing of catalytic activities.

We study the problems of pricing an indivisible product to consumers who are embedded in a given social network. The goal is to maximize the revenue of the seller by the so-called iterative pricing that offers consumers a sequence of prices over time. The consumers are assumed to be impatient in that they buy the product as soon as the seller posts a price not greater than their valuations of the product. The product's value for a consumer is determined by two factors: a fixed consumer-specified intrinsic value and a variable externality that is exerted from the consumer's neighbors in a linear way. We focus on the scenario of negative externalities, which captures many interesting situations, but is much less understood in comparison with its positive externality counterpart. Assuming complete information about the network, consumers' intrinsic values, and the negative externalities, we prove that it is NP-hard to find an optimal iterative pricing, even for unweighted tree networks with uniform intrinsic values. Complementary to the hardness result, we design a 2-approximation algorithm for general weighted networks with (possibly) nonuniform intrinsic values. We show that, as an approximation to optimal iterative pricing, single pricing works fairly well for many interesting cases, such as forests, Erdźs---Renyi networks and Barabasi---Albert networks, although its worst-case performance can be arbitrarily bad in general networks.

Saliency can be modeled as spatially localized and contrasted structures with higher blob density and higher blob evenness across scales in images. And it is likely to contain regions and objects of interest. So saliency detection is desired before further image processing and analysis. This paper presented an automatic and effective method for saliency detection in satellite images, based on multi-scale blob information. Firstly, multi-scale blob information were extracted from input images, to produce a blob map. Then, in the blob map, multi-level distance transform spread the blob information to the entire image, to generate a saliency map. Finally the saliency map was segmented to detect salient regions and to locate object centers. The experimental results illustrated its accuracy and stability for detecting salient regions (such as residential areas, parking lots and airplane docks) and for locating object centers in various satellite images.

Recent studies have indicated that long non-coding RNAs (lncRNAs) could act as non-invasive tumor markers in both diagnosis and predicting the prognosis. In this study, we focused to determine the expression of circulating lncRNAs in patients suffering from non-small-cell lung cancer (NSCLC), aiming to found the potential lncRNA as predictor. Twenty-one lncRNAs which previously identified were selected as candidate targets for subsequent circulating lncRNA assay. The candidate lncRNAs were validated by qRT-PCR arranged in the training and validation sets. Circulating SPRY4-IT1, ANRIL, and NEAT1 were significantly increased in plasma samples of NSCLC patients during training set and validation set. Receiver operating characteristic curve (ROC) analysis revealed that plasma ANRIL provided the highest diagnostic performance with an area under ROC curve value (AUC) of 0.798. Further combination with the three factors indicated a higher power (AUC, 0.876; sensitivity, 82.8 %; specificity, 92.3 %). The stableness detection of the three factors indicated that circulating SPRY4-IT1, ANRIL, and NEAT might serve as a predictor for the early warning of non-small-cell lung cancer.

We report the theoretical investigation of an electrically injected plasmonic nanolaser in visible regime. The green nanolaser is based on a hybrid waveguide which employs semiconductor nanowire gain medium to compensate the loss in metallic cavity. Two-dimensional sub-wavelength confinements (mode area about λ 2/100) and net modal gain are simultaneously achieved for quasi-one-dimensional surface plasmon mode supported in such waveguide. The device structure is further optimized for room temperature operation with achievable injected current density about several kilo ampere/square centimetres (kA/cm2). The approach is also beneficial to developing other nanophotonic devices on sub-wavelength scale.

Automatic information extraction from optical remote sensing images is still a challenge for large-scale remote sensing applications. For instance, artificial sample collection cannot achieve an automatic remote sensing imagery classification. Based on this, this paper resorts to the technologies of change detection and transfer learning, and further proposes a prior knowledge-based automatic hierarchical classification approach for detailed land cover updating. To establish this method, an automatic sample collection scheme for object-oriented classification is presented. Unchanged landmarks are first located. Prior knowledge of these categories from previously interpreted thematic maps is then transferred to the new target task. The knowledge is utilized to rebuild the relationship between landmark classes and their spatial-spectral features for land cover updating. A series of high-resolution remote sensing images are experimented for validating the effectiveness of the proposed approach in rapidly updating detailed land cover. The results show that, with the assistance of preliminary thematic maps, the approach can automatically obtain reliable object samples for object-oriented classification. Detailed land cover information can be excellently updated with a competitive accuracy, which demonstrates the practicability and effectiveness of our method. It creates a novel way for employing the technologies of knowledge discovery into the field of information extraction from optical remote sensing images.

The potential of a plasmonic nanolaser using semiconductor gain to compensate the metal loss was investigated theoretically in multilayer planar structure geometry. The propagation constant of surface plasmon (SP) mode, Purcell factor, and modal gain were calculated via transfer matrix method. Near SP resonance, the Purcell factor shows sensitive frequency dependence and exponential decay with distance. The huge Purcell factor leads to an impractical current density about several hundreds kiloampere/square centimeter (kA/cm2). When the spectra peak of optical gain in a semiconductor is shifted about 0.7 eV below SP resonance, the moderate Purcell factor shows a rather broadband enhancement. Net modal gain was achieved at an injected current density of 12.1 kA/cm2, comparable to that of conventional photonic laser diodes. The structure is further optimized by inserting a (low permittivity) dielectric spacer between the semiconductor active region and metal.

Given a connected graph G = (V,E) with a nonnegative cost on each edge in E, a nonnegative prize at each vertex in V, and a target set V′ ⊆ V, the Prize Collecting Steiner Tree (PCST) problem is to find a tree T in G interconnecting all vertices of V′ such that the total cost on edges in T minus the total prize at vertices in T is minimized. The PCST problem appears frequently in practice of operations research. While the problem is NP-hard in general, it is polynomial-time solvable when graphs G are restricted to series-parallel graphs.

In order to solve the problems of GaN heteroepitaxy on sapphire substrate, some techniques were explored. Freestanding GaN substrates have been made by hydride vapor phase epitaxy (HVPE), laser lift-off (LLO), and chemical mechanical polishing techniques. Wafer bending and cracking in the HVPE growth were partly settled by pulsed flow modulation method. High-crystal quality was established for 1.2 mm thick GaN substrate by X-ray diffraction measurement, in which the full width of half maximum values were 72, 110 arcsec for (102), (002) peaks. A novel micro-size patterned sapphire substrate (PSS) and a nano PSS were also fabricated. High-power vertical structure light emitting diodes (VSLEDs) have been developed by Au–Sn eutectic wafer bonding, homemade micro-area LLO, and light extraction structure preparation. The high-injection-level active region with low temperature GaN sandwiched layers was used for low-efficiency droop. The light output power of VSLED was achieved as 400 mW driven at 350 mA, and the dominant wavelength is about 460 nm. The structures and properties of strain modulated superlattices (SLs) and quantum wells as well as advanced simulation of carriers transport across the electron blocking layer were investigated in laser diodes. The hole concentration was achieved as high as 1.6 × 1018 cm−3 in AlGaN/GaN SLs:Mg by inserting an AlN layer. High-quality AlGaN epilayers and structures were grown by MOCVD. Some device structures of UV LEDs and detectors were demonstrated. The emission wavelength of 262 nm UV LED has been successfully fabricated. At last, high-quality InN and InGaN materials for solar cell were grown by boundary-temperature-controlled epitaxy and growth-temperature-controlled epitaxy. Hall-effect measurement showed a recorded electron mobility of 3,280 cm2/(V s) and a residual electron concentration of 1.47 × 1017 cm−3 at 300 K.

AlN with different thicknesses were grown as in- terlayers (ILs) between GaN and p-type Al0.15Ga0.85N/GaN superlattices (SLs) by metal organic vapor phase epitaxy (MOVPE). It was found that the edge-type threading dis- location density (TDD) increased gradually from the mini- mum of 2.5 × 10 9 cm −2 without AlN IL to the maximum of 1 × 10 10 cm −2 at an AlN thickness of 20 nm, while the screw-type TDD remained almost unchanged due to the interface-related TD suppression and regeneration mech- anism. We obtained that the edge-type dislocations acted as acceptors in p-type AlxGa1−xN/GaN SLs, through the comparison of the edge-type TDD and hole concentration with different thicknesses of AlN IL. The Mg activation en- ergy was significantly decreased from 153 to 70 meV with a 10-nm AlN IL, which was attributed to the strain modula- tion between AlGaN barrier and GaN well. The large acti- vation efficiency, together with the TDs, led to the enhanced hole concentration. The variation trend of Hall mobility was also observed, which originated from the scattering at TDs.

Two ultraviolet InGaN/GaN light emitting diodes (LEDs) with and without InGaN underlying layer beneath the multiple quantum wells (MQWs) were grown by metal-organic vapor phase epitaxy. Based on the photoluminescence excitation measurements, it was found that the Stokes shift of the sample with a 10-nm-thick In0.1Ga0.9N underlying layer was about 64 meV, which was smaller than that of the reference sample without InGaN underlying layer, indicating a reduced quantum-confined Stark effect (QCSE) due to the decrease of the piezoelectric polarization field in the MQWs. In addition, by fitting the photon energy dependence of carrier lifetime values, the radiative recombination lifetime of the sample with and without InGaN underlying layer were obtained about 1.22 and 1.58 ns at 10 K, respectively. The shorter carrier lifetime also confirmed that the QCSE in the MQWs was weakened after inserting the InGaN underlying layer. In addition, although the depth of carrier localization in the sample with InGaN underlying layer became smaller, the nonradiative recombination centers (NRCs) inside it decreased, and thus suppressed the nonradiative recombination process significantly according to the electroluminescence measurement results. Compared to the reference sample, the efficiency droop behavior was delayed in the sample with InGaN underlying layer and the droop effect was also effectively alleviated. Therefore, the enhanced light-emission efficiency of ultraviolet InGaN/GaN MQW LEDs could be attributed to the decrease of QCSE and NRCs.

Consider a connected graph G=(V,E). For a pair of nodes u and v, denote by M uv the set of intermediate nodes of a shortest path between u and v. We are intertested in minimization of the union ? u,v?V M uv . We will show that this problem is NP-hard and cannot have polynomial-time ?ln?-approximation for 0<1 unless NP?DTIME(n O(loglogn)) where ? is the maximum node degree of input graph. We will also construct a polynomial-time $H(\frac{\delta (\delta -1)}{2})$ -approximation for the problem where H(?) is the harmonic function.

Object-oriented remotely sensed images processing method has been accepted by more and more experts of remote sensing. To advance the efficiency of data processing, parallel image computing is a good choice since large volumes of data need be analyzed efficiently and rapidly. This paper presents the information extraction method based on per-parcel extraction of high-resolution remotely sensed image; to extract efficiently different information from remotely sensed image, this paper gives the research idea of image rough-classification based on large-scale and subtle-segmentation based on small-scale; to improve the efficiency of image processing, we adapt parallel computing method to solve this problem by presenting an new data-partition method. At last this paper gives the implementation of the research idea based on Message Passing Interface (MPI) and analyzes our experimental system efficiency, and the results show that the new methods can improve the efficiency of high-resolution remotely sensed image data processing efficiently and have a good application.

In the application of multiple-processor systems some processors or links in a system may not function properly, thus the fault diagnosis is one of the most important issues in the analysis and maintenance of those systems. For the practical fault diagnosis systems, the probability that all neighboring processors of a processor are faulty simultaneously is very small. Thus, the conditional diagnosability, which is a new metric for evaluating such systems, assumes that every fault set does not contain all neighbors of any processor in the system. In this paper, the authors show that the n-dimensional shuffle-cube has the conditional diagnosability of 4n − 15 for n ≡ 2 (mod4) and n ≥ 10.

A wide range of applications for wireless ad hoc networks are time-critical and impose stringent requirement on the communication latency. One of the key communication operations is to broadcast a message from a source node. This paper studies the minimum latency broadcast scheduling problem in wireless ad hoc networks under collision-free transmission model. The previously best known algorithm for this NP-hard problem produces a broadcast schedule whose latency is at least 648(rmax/rmin)2 times that of the optimal schedule, where rmax and rmin are the maximum and minimum transmission ranges of nodes in a network, respectively. We significantly improve this result by proposing a new scheduling algorithm whose approximation performance ratio is at most (1 + 2rmax/rmin)2 + 32. Moreover, under the proposed scheduling each node just needs to forward a message at most once.

In this paper we consider how to collect data from sensors deployed in the Euclidean plane in a time-efficient way. We assume that all sensors could adjust their transmission ranges and aggregate data received from other sensors. We adopt a collision-free transmission model using proper schedules for data transmission. We study the problem of finding the schedule under which data from all sensors could be transmitted to the data sink in the minimal time. We propose an approximation algorithm for this NP-hard problem whose performance ratio is bounded by a constant. This significantly improves the existing approximation algorithm that does not have a constant performance ratio.