Grid Multiscroll Hyperchaotic Attractors Based on Colpitts Oscillator Mode with Controllable Grid Gradient and Scroll Numbers

AbstractThrough introducing two piecewise-linear triangular wave functions in a three-dimensional spiral chaotic Colpitts oscillator model, a four-dimensional grid multiscroll hyperchaotic system is constructed. Interestingly, by adjusting a build-in parameter in a variable of one triangle wave function, the control of the gradient of the multiscroll grid is achieved. Whereas by deploying the zero points of the two triangular wave functions to extend the saddle-focus equilibrium points with index-2 in phase space the scroll numbers do not only increase along with the number of turning points, but they can also generate arbitrary multiples of products. The basic dynamical behaviors of the proposed four-dimensional multiscroll hyperchaotic system are analyzed. Finally, the hardware experimental circuit is designed and the interrelated circuit implementation is realized. The experimental results are in agreement with both theoretical analyses and numerical simulations, which verify the feasibility of the design methods

Characteristics and variations of the picophytoplankton community in the Arctic Ocean

Picophytoplankton are responsible for much of the carbon fixation process in the Arctic Ocean, and they play an important role in active microbial food webs. The climate of the Arctic Ocean has changed in recent years, and picophytoplankton, as the most vulnerable part of the high-latitude pelagic ecosystem, have been the focus of an increasing number of scientific studies. This paper reviews and summarizes research on the characteristics of picophytoplankton in the Arctic Ocean, including their abundance, biomass, spatial distribution, seasonal variation, community structure, and factors influencing their growth. The impact of climate change on the Arctic Ocean picophytoplankton community is discussed, and future research directions are considered

Distinct biogeographic patterns for archaea, bacteria, and fungi along the vegetation gradient at the continental scale in Eastern China

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in mSystems 2 (2017): e00174-16, doi:10.1128/mSystems.00174-16.The natural forest ecosystem in Eastern China, from tropical forest to boreal forest, has declined due to cropland development during the last 300 years, yet little is known about the historical biogeographic patterns and driving processes for the major domains of microorganisms along this continental-scale natural vegetation gradient. We predicted the biogeographic patterns of soil archaeal, bacterial, and fungal communities across 110 natural forest sites along a transect across four vegetation zones in Eastern China. The distance decay relationships demonstrated the distinct biogeographic patterns of archaeal, bacterial, and fungal communities. While historical processes mainly influenced bacterial community variations, spatially autocorrelated environmental variables mainly influenced the fungal community. Archaea did not display a distance decay pattern along the vegetation gradient. Bacterial community diversity and structure were correlated with the ratio of acid oxalate-soluble Fe to free Fe oxides (Feo/Fed ratio). Fungal community diversity and structure were influenced by dissolved organic carbon (DOC) and free aluminum (Ald), respectively. The role of these environmental variables was confirmed by the correlations between dominant operational taxonomic units (OTUs) and edaphic variables. However, most of the dominant OTUs were not correlated with the major driving variables for the entire communities. These results demonstrate that soil archaea, bacteria, and fungi have different biogeographic patterns and driving processes along this continental-scale natural vegetation gradient, implying different community assembly mechanisms and ecological functions for archaea, bacteria, and fungi in soil ecosystems.This research was financially supported by the National Natural Science Foundation of China (grant number 41520104001), the 111 Project, and the Fundamental Research Funds for the Central Universities

Efficacy and safety of pembrolizumab with preoperative neoadjuvant chemotherapy in patients with resectable locally advanced head and neck squamous cell carcinomas

BackgroundThis study aimed to explore the efficacy and safety of pembrolizumab combined with chemotherapy as neoadjuvant therapy in patients with resectable locally advanced head and neck squamous cell carcinomas (LA-HNSCCs).MethodsIn this prospective, single-arm, single-centre clinical trial, patients meeting the inclusion criteria were treated with preoperative neoadjuvant therapy with 200 mg pembrolizumab combined with 75 mg/m2 cisplatin and 175 mg/m2 paclitaxel. This was followed by surgery and postoperative adjuvant therapy. The primary endpoint was the postoperative pathological complete response (pCR) rate. All statistical analyses were performed using SPSS 26.ResultsA total of 22 patients were enrolled. The location of primary lesion showed: hypopharynx were 15 (68.2%), oropharynx were 6 (27.3%) and oral cavity was 1 (4.5%). The postoperative pCR rate, was 36.4% (8/22), and there was no delay to surgery due to adverse drug reactions. The rate of laryngeal function preservation was 90.9% (20/22). Delayed wound healing was the main surgical complication, with an incidence of 22.7% (5/22). The median follow-up time was 9.5 months, and only 1 patient (4.55%) suffered a regional recurrence.ConclusionPreoperative treatment with pembrolizumab and chemotherapy in resectable LA-HNSCC has a high pCR rate with no significant impact on surgical safety. This treatment was found to increase the rate of laryngeal function preservation. However, the effects of neoadjuvant immunotherapy on long-term prognosis in LA-HNSCCs require further study

Spatial distribution of per- and polyfluoroalkyl compounds in coastal waters from the East to South China Sea

The spatial distribution of per- and polyfluoroalkyl compounds (PFCs) were investigated in coastal waters collected onboard research vessel Snow Dragon from the East to South China Sea in 2010. All samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(-)ESI-MS/MS). Concentrations of 9 PFCs, including C4 and C8 (PFBS, PFOS) perfluoroalkyl sulfonate (PFSAs), C 5-C9 and C13 (PFPA, PFHxA, PFHpA, PFOA, PFNA, PFTriDA) perfluoroalkyl carboxylates (PFCAs), and N-ethyl perfluorooctane sulfonamide (EtFOSA) were quantified. The 危PFC concentrations ranged from 133 pg/L to 3320 pg/L, with PFOA (37.5-1541 pg/L), PFBS (23.0-941 pg/L) and PFHpA (0-422 pg/L) as dominant compounds. Concentrations of PFCs were greater in coastal waters along Shanghai, Ningbo, Taizhou, Xiamen and along coastal cities of the Guangdong province compared to less populated areas along the east Chinese coast. Additionally, the comparison with other seawater PFC measurements showed lower levels in this study. 漏 2011 Elsevier Ltd. All rights reserved

Occurrence of Perfluoroalkyl Compounds in Surface Waters from the North Pacific to the Arctic Ocean

Chinese Arctic and Antarctic Administration; National Natural Science Foundation of China [40776003]Perfluoroalkyl compounds (PFCs) were determined in 22 surface water samples (39-76 degrees N) and three sea ice core and snow samples (77-87 degrees N) collected from North Pacific to the Arctic Ocean during the fourth Chinese Arctic Expedition in 2010. Geographically, the average concentration of Sigma PFC in surface water samples were 560 +/- 170 pg L-1 for the Northwest Pacific Ocean, 500 +/- 170 pg L-1 for the Arctic Ocean, and 340 +/- 130 pg L-1 for the Bering Sea, respectively. The perfluoroalkyl carboxylates (PFCAs) were the dominant PFC class in the water samples, however, the spatial pattern of PFCs varied. The C-5, C-7 and C-8 PFCAs (i.e., perfluoropentanoate (PFPA), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA)) were the dominant PFCs in the Northwest Pacific Ocean while in the Bering Sea the PFPA dominated. The changing in the pattern and concentrations in Pacific Ocean indicate that the PFCs in surface water were influenced by sources from the East-Asian (such as Japan and China) and North American coast, and dilution effect during their transport to the Arctic. The presence of PFCs in the snow and ice core samples indicates an atmospheric deposition of PFCs in the Arctic. The elevated PFC concentration in the Arctic Ocean shows that the ice melting had an impact on the PFC levels and distribution. In addition, the C-4 and C-5 PFCAs (i.e., perfluorobutanoate (PFBA), PFPA) became the dominant PFCs in the Arctic Ocean indicating that PFBA is a marker for sea ice melting as the source of exposure

The Generalized 4-Connectivity of Cube-Connected-Cycle and Hierarchical Hypercube

The connectivity is an important measurement for the fault tolerance of a network. Let G=VG,EG be a connected graph with the vertex set VG and edge set EG. An S-tree of graph G is a tree T that contains all the vertices in S subject to S⊆VG. Two S-trees T and T′ are internally disjoint if and only if ET∩ET′=∅ and VT∩VT′=S. Denote κGS by the maximum number of internally disjoint S-trees in graph G. The generalized k-connectivity is a natural generalization of the classical connectivity, which is defined as κrG=minκGS|S⊆VGandS=r. In this paper, we mainly focus on the generalized connectivity of cube-connected-cycle CCCn and hierarchical hypercube HHCn, which were introduced for massively parallel systems. We show that for n=2m+2m≥1, κ4HHCn=m and κ4CCCn=2, that is, for any four vertices in CCCn (or HHCn), there exist 2 (or m) internally disjoint S-trees connecting them in CCCn (or HHCn)

Spatial Spillover of House Prices: An Empirical Study of the Yangtze Delta Urban Agglomeration in China

This study investigates the spatial dependence of house prices in the Yangtze Delta Urban Agglomeration since the year 2000. According to Moran’s I index and the LISA scatter plot derived from a cross-section data set, the spatial dependence of house prices can be traced across the 25 cities in the agglomeration and became more evident after 2005. This study develops a spatial panel model with geographical distance and economic distance weight matrices. Spatial effects significantly influenced house prices in both cases but the intensity of the former was weaker than for the latter. Income, proportion of the tertiary industry, and amenity exhibited significant indirect effects on house prices in other cities in the inner region of the agglomeration, while competition of population between cities with economic proximity exerted negative indirect effects. Furthermore, urban industrial structure, innovation capability, and urbanization degree revealed differences in terms of spatial dependence among various city groups

Antioxidant Activity, Functional Properties, and Cytoprotective Effects on HepG2 Cells of Tree Peony (Paeonia suffruticosa Andr.) Seed Protein Hydrolysate as Influenced by Molecular Weights Fractionation

In recent years, plant protein hydrolysates have gained increased attention due to their superior antioxidant activity and potential to prevent several chronic diseases associated with oxidative stress. This study aimed to investigate the antioxidant activity, functional properties, and cytoprotective effects of the tree peony seed protein hydrolysate (TPSPH) with different molecular weights (MWs). The antioxidant activities were evaluated by DPPH, hydroxyl radicals scavenging, Fe2+ chelating, and inhibition of the β-carotene oxidation abilities. The protective effects and mechanism against oxidative stress were determined using H2O2-stressed HepG2 cells. MW > 30 kDa of TPSPH showed the highest radical scavenging (DPPH IC50 = 0.04, hydroxyl IC50 = 0.89 mg/mL) and inhibition of β-carotene oxidation (80.07% at 2.0 mg/mL) activity. Moreover, MW > 30 kDa possessed high hydrophobicity, emulsifying capacity, and abundant antioxidant amino acids (28.22% of hydrophobic amino acids and 8.3% of aromatic amino acids). MW 5–10 kDa exhibited more effective protection against H2O2-induced HepG2 cells, by reducing reactive oxygen species (ROS), malonaldehyde (MDA), lactate dehydrogenase (LDH), and activating antioxidant enzymes (superoxide dismutase and catalase). These results indicated the potential application of TPSPH as an antioxidant in food and functional foods

Numerical Simulation of a New Porous Medium Burner with Two Sections and Double Decks

Porous medium burners are characterized by high efficiency and good stability. In this study, a new burner was proposed based on the combustion mechanism of the methane-air mixture in the porous medium and the preheating effect. The new burner is a two-section and double-deck porous medium with gas inlets at both ends. A mathematical model for the gas mixture combustion in the porous medium was established. The combustion performance of the burner was simulated under different equivalence ratios and inlet velocities of premixed gas. The methane combustion degree, as well as the temperature and pressure distribution, was estimated. In addition, the concentrations of emissions of NOx for different equivalence ratios were investigated. The results show that the new burner can not only realize sufficient combustion but also save energy. Furthermore, the emission concentration of NOx is very low. This study provides new insights into the industrial development and application of porous medium combustion devices