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We introduce a density-based clustering method called skeleton clustering that can detect clusters in multivariate and even high-dimensional data with irregular shapes. To bypass the curse of dimensionality, we propose surrogate density measures that are less dependent on the dimension but have intuitive geometric interpretations. The clustering framework constructs a concise representation of the given data as an intermediate step and can be thought of as a combination of prototype methods, density-based clustering, and hierarchical clustering. We show by theoretical analysis and empirical studies that the skeleton clustering leads to reliable clusters in multivariate and high-dimensional scenarios.

Molybdenum sulfide (MoS2) with well-designed porous structure has the potential to be great electrode materials in sodium-ion batteries due to its high theoretical capacity and abundant resource, however, hindered by its intrinsic low conductivity and stability. Herein, MoS2 with 3D macroporous foam structure and high conductivity was obtained through SiO2 templates and integrated with carbon paper (3D F-MoS2/CP). It has showed superior specific capacity (225 mA h g−1, 0.4–3 V) and cycling stability (1000 cycles) at high rate (2000 mA g−1), with a low decay rate (0.033% per cycle) in sodium-ion batteries. The excellent electrochemical performance may originate from its unique integrated structure: 3D MoS2 macropores providing high surface area and abundant transfer channels while carbon paper enhancing the conductivity of MoS2 and avoiding unnecessary side reactions brought by binder addition.

CircHIPK3 is a type of endogenous circular RNA, which contains a covalently closed circular structure and cannot encode protein or polypeptide. CircHIPK3 is unusually expressed in varieties of tumors and plays dual roles of tumor promotion or tumor inhibition in tumorigenesis and development of tumors by serving as the sponge for miRNA in multiple tumors. Here, we reviewed the differential expression, the dual functions, the regulation mechanism, and the network in a variety of tumors as well as the potential value for the diagnosis and treatment of tumors, which are of great significance for our comprehensive understanding of the roles and mechanisms of circHIPK3 in tumors.

Noise exposure and aging can cause subclinical hearing problems that are not identified with conventional audiometry. Nerve damage among the normal hearing could reduce afferent auditory-nerve activity consequently reducing the middle ear muscle reflex (MEMR). It was hypothesized that normal-hearing individuals reporting more noise exposure would have slower growth of MEMR with increasing levels. Data were analyzed from sixty-one young, normal-hearing people. Each completed the four MEMR assessments and the Life-Time Exposure to Noise and Solvents Questionnaire. Reflex amplitudes were measured as a function of sound level using clinical equipment. High-pass noise stimuli (1.5-4.0 kHz) and a 1-KHz tone were used as elicitors with a 226-Hz probe tone. Data were analyzed using a linear mixed effects model. Individuals reporting higher noise exposure with the LENS-Q had significantly reduced growth of MEMR with level, supporting the hypothesis. Independent effects of age and gender were also observed. The effect of the pure-tone average on MEMR growth functions did not reach significance at the 5% level (p = 0.052). No significant relationships were observed between the MEMR measures and extended high-frequency thresholds nor with word recognition in noise. The results suggest that the MEMR could indicate subclinical nerve damage.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most important diseases in pigs. MicroRNAs (miRNAs) have emerged as an important regulator of virus-host cell interactions and miR-30c has been found to facilitate PRRSV replication. Here, we found that the interferon-alpha/beta receptor beta chain (IFNAR2) was down-regulated, while miR-30c was up-regulated during HV (a highly pathogenic type 2 PRRSV strain) and CH-1a (a classic type 2 PRRSV strain) infection. Subsequently, using bioinformatics analysis, we predicted that the IFNAR2 was targeted by miR-30c. A luciferase assay verified that the 3' UTR of IFNAR2 was targeted by miR-30c, as a mutation on either the target sequence or the miR-30c seed sequence reversed the luciferase activity. In addition, miR-30c and IFNAR2 mRNA were physically co-localized in RNA-induced silencing complex (RISC). Importantly, we showed that miR-30c also impaired the induction of IFN-stimulated genes (ISGs) by targeting IFNAR2. Our findings further reveal the mechanism of miR-30c promoting PRRSV replication.

The construction of integrated solar storage and charging power stations has become the key issue in the development of new energy. The effects of insufficient power supply, effective charging time, load uncertainty and user evaluation during the operation of charging stations are comprehensively considered in this paper, and a safety evaluation index system based on fuzzy comprehensive evaluation theory is proposed. In order to ensure the accuracy of the comprehensive evaluation results, a two-layer evaluation model is used for fuzzy comprehensive evaluation to avoid too small weight values of evaluation factors. Finally, an example is given to prove the effectiveness of the evaluation model.

In a previous study, we have shown that highly-pathogenic PRRSV (HP-PRRSV) nonstructural protein 4 (nsp4) antagonizes type I IFN expression induced by poly(I:C). Here, we demonstrated that the mutation of Aspartic acid 185 (Asp185) impaired the ability of nsp4 to inhibit IFN-I production induced by poly(I:C). Subsequently, we verified that all the mutants at the residue 185, regardless of amino acid size (including Cys and Ser) and charge (including Glu and Lys), impaired nsp4 catalytic activity. However, when Asp185 in nsp4 was replaced by a similar structure amino acid Asparagine 185 (Asn185), nsp4 stayed but with a decreased protease activity. Importantly, the recombinant virus with Asn185 mutation in HP-PRRSV-nsp4 exhibited slower replication rate and higher ability to induce IFN-I expression compared with wild-type (wt) HP-PRRSV.

Noise exposure and aging can cause subclinical hearing problems that are not identified with conventional audiometry. Potential clinical assessments were studied that could identify subclinical hearing deterioration: (1) Electrocochleography (ECoG); (2) Middle Ear Muscle Reflex (MEMR); (3) Extended High Frequency (EHF) thresholds (10–16 kHz); and (4) word recognition in noise. Sixty-one young, normal-hearing people were recruited. Each completed the four auditory assessments and the Life-Time Exposure to Noise Solvents Questionnaire (LENS-Q). ECoG and MEMR measurements were measured as a function of sound level using clinical equipment. Word recognition in noise was measured with a diotic, closed-set, 12-alternative spondees-in-noise test. It was hypothesized that normal-hearing individuals reporting more noise exposure would have slower growth of the ECoG measures and MEMR magnitudes with increasing levels. Individuals reporting higher noise exposure with the LENS-Q had significantly reduced MEMR magnitudes and smaller slopes, supporting the hypothesis. Gender effects were observed. No significant effect of self-report noise-exposure was seen with ECoG AP growth functions or SP/AP ratios, though modest age effects were observed. EHF thresholds were the only significant predictor of word recognition in noise. The results suggest that word recognition in noise, EHF audiometry, and MEMR could indicate subclinical hearing problems.

Porcine reproductive and respiratory syndrome virus (PRRSV) is widely prevalent in pigs, resulting in significant economic losses worldwide. A compelling impact of PRRSV infection is severe pneumonia. In the present study, we found that interleukin-17 (IL-17) was upregulated by PRRSV infection. Subsequently, we demonstrated that PI3K and p38MAPK signaling pathways were essential for PRRSV-induced IL-17 production as addition of phosphatidylinositol 3-kinase (PI3K) and p38MAPK inhibitors dramatically reduced IL-17 production. Furthermore, we show here that deleting the C/EBPβ and CREB binding motif in porcine IL-17 promoter abrogated its activation and that knockdown of C/EBPβ and CREB remarkably impaired PRRSV-induced IL-17 production, suggesting that IL-17 expression was dependent on C/EBPβ and CREB. More specifically, we demonstrate that PRRSV nonstructural protein 11 (nsp11) induced IL-17 production, which was also dependent on PI3K-p38MAPK-C/EBPβ/CREB pathways. We then show that Ser74 and Phe76 amino acids were essential for nsp11 to induce IL-17 production and viral rescue. In addition, IRAK1 was required for nsp11 to activate PI3K and enhance IL-17 expression by interacting with each other. Importantly, we demonstrate that PI3K inhibitor significantly suppressed IL-17 production and lung inflammation caused by HP-PRRSV in vivo, implicating that higher IL-17 level induced by HP-PRRSV might be associated with severe lung inflammation. These findings provide new insights onto the molecular mechanisms of the PRRSV-induced IL-17 production and help us further understand the pathogenesis of PRRSV infection. IMPORTANCE Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) associated with severe pneumonia has been one of the most important viral pathogens in pigs. IL-17 is a proinflammatory cytokine that might be associated with the strong inflammation caused by PRRSV. Therefore, we sought to determine whether PRRSV infection affects IL-17 expression, and if so, determine this might partially explain the underlying mechanisms for the strong inflammation in HP-PRRSV-infected pigs, especially in lungs. Here, we show that PRRSV significantly induced IL-17 expression, and we subsequently dissected the molecular mechanisms about how PRRSV regulated IL-17 production. Furthermore, we show that Ser74 and Phe76 in nsp11 were indispensable for IL-17 production and viral replication. Importantly, we demonstrated that PI3K inhibitor impaired IL-17 production and alleviated lung inflammation caused by HP-PRRSV infection. Our findings will help us for a better understanding of PRRSV pathogenesis.

Many techniques in harmonic analysis use the fact that a continuous object can be written as a sum (or an intersection) of dyadic counterparts, as long as those counterparts belong to an adjacent dyadic system. Here we generalize the notion of adjacent dyadic system and explore when it occurs, leading to some new and perhaps surprising classifications. In particular, we show that every dyadic grid is determined by two parameters, the \emph{shift} and the \emph{location}; moreover two dyadic grids form an adjacent dyadic system if and only if their shifts and locations satisfy readily verifiable conditions., Final revised version to appear in Mathematische Annalen

Trough collectors are laid out in rows in a field withrow spacing. Wind and sandstorm loads on the collectors will be influenced by surrounding collectors. This paper presents analyzed results from a combined wind tunnel and sandstorm tunnel study on a trough collector field with seven rows and five spans. In wind tunneltests, the measured model with pressure taps was installed in the field to measure wind pressures on the surfaces. Mean and fluctuating pressures on the model were measured by the synchronous multi-pressure sensing system under typical boundary layer wind flow field. In sandstorm tunneltests,a isolated trough collector model was measured by the high-frequency force balance technique under wind-blown sand flow field.

Truncated electrodes with different cone angle are widely used in vehicle body assembly. However, the effect of the cone angle on welding process still keeps unclear. In this paper, a multi-physics finite element model, which considered the coupling of electric field, magnetic field, fluid flow and heat transfer, was used to study the effect of the cone angle variation on resistance spot welding. Four kinds of cone angles, including 15°, 30°, 45°, and 60°, were studied systematically. Research results showed that the cone angle variation affects not only weld quality but also electrode life. Specifically, the lower cone angle, the more severe current density singularity at the tip edge, the stronger electromagnetic stirring in the molten nugget, and thus the stronger fluid flow and more uniform temperature field in the weld nugget, which would produce a positive effect on the weld quality. At the same time, the low cone angles would enhance the cooling ability of the electrode for the increased mass and present lower electrode temperature, and thus have a better electrode life, which was also verified with electrode wear experiments. However, the low cone angle electrodes would produce smaller nuggets and consume more coppers. Moreover, for the small cone angle electrode, a larger welding current has to be applied to compensate the heat dissipated by the electrodes due to their excellent cooling capability. As a result, considering the effects of the electrode cone angle on electrode life, weld quality and production cost, the 30° and 45° cone angle would be recommended in vehicle body production.

Implementation of lightweight low-ductility materials such as aluminum alloys, magnesium alloys and composite materials has become urgently needed for automotive manufacturers to improve the competitiveness of their products. However, the hybrid use of these materials poses big challenges to joining processes. Self-piercing riveting (SPR) is currently the most popular technique for joining dissimilar materials and has been widely used in joining all-aluminum and multi-material vehicle bodies. However, in riveting magnesium alloys, cracks always occur for its low ductility. In this paper, a hybrid joining process named friction self-piercing riveting (F-SPR), which combines mechanical joining mechanism of SPR with solid-state joining mechanism of friction stir spot welding (FSSW) by making rivet rotating at high speed in riveting process, was proposed aiming at joining the low ductility materials. 1-mm-thick AA6061-T6 and 2-mm-thick AZ31B were used to validate the effectiveness of the F-SPR process. The results showed that the F-SPR process could significantly improve the rivetability of magnesium alloys, and greatly increase the joint strength, comparing with traditional SPR process.Copyright © 2013 by ASME

Implementation of lightweight low-ductility materials such as aluminum alloys, magnesium alloys and composite materials has become urgently needed for automotive manufacturers to improve the competitiveness of their products. However, hybrid use of these materials poses big challenges to traditional joining process. Self-piercing riveting (SPR) is currently the most popular technique for joining dissimilar materials and has been widely used in joining all-aluminum and multimaterial vehicle bodies. However, in riveting magnesium alloys, cracks always occur for its low ductility. In this paper, a hybrid joining process named friction self-piercing riveting (F-SPR), which combines mechanical joining mechanism of SPR with solid-state joining mechanism of friction stir spot welding (FSSW) by making rivet rotating at high speed in riveting process, was proposed aiming at joining the low-ductility materials. The effectiveness of the F-SPR process was validated via riveting 1 mm thick AA6061-T6 and 2 mm thick AZ31B. The results showed that the F-SPR process could significantly improve the rivetability of magnesium alloys, and greatly increase the joint strength, comparing with the traditional SPR process.