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To enhance the accuracy of hydrodynamic forces predictions for underwater vehicle within certain resource constraints, this study integrates high and low-fidelity samples using the Co-Kriging method, combined with an expected improvement (EI) sequential infill criterion to construct a hydrodynamic forces prediction model. Different grid densities of computational fluid dynamics (CFD) calculations are used to distinguish high and low-fidelity samples. Taking the Joubert BB2 underwater vehicle as the research object, hydrodynamic forces predictions are conducted for various angles of attack and speeds. The effectiveness of the EI infill criterion in improving model prediction accuracy is validated. Furthermore, compared to the traditional Kriging model under the same computational resources, the Co-Kriging method, which integrates high and low-fidelity samples, significantly outperforms the Kriging model constructed solely from high or low-fidelity samples in overall prediction accuracy for underwater vehicle hydrodynamic forces. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Key message: The resistance of Huaidao5 results from the high constitutive expression of tolerance genes, while that of Huaidao9 is due to the cold-induced resistance in flag leaves and panicles. The regulation mechanism of rice seedlings' cold tolerance is relatively clear, and knowledge of its underlying mechanisms at the reproductive stage is limited. We performed differential expression and co-expression network analyses to transcriptomes from panicle and flag leaf tissues of a cold-tolerant cultivar (Huaidao5), and a sensitive cultivar (Huaidao9), under reproductive-stage cold stress. The results revealed that the expression levels of genes in stress-related pathways such as MAPK signaling pathway, diterpenoid biosynthesis, glutathione metabolism, plant–pathogen interaction and plant hormone signal transduction were constitutively highly expressed in Huaidao5, especially in panicles. Moreover, the Hudaidao5's panicle sample-specific (under cold) module contained some genes related to rice yield, such as GW5L, GGC2, SG1 and CTPS1. However, the resistance of Huaidao9 was derived from the induced resistance to cold in flag leaves and panicles. In the flag leaves, the responses included a series of stress response and signal transduction, while in the panicles nitrogen metabolism was severely affected, especially 66 endosperm-specific genes. Through integrating differential expression with co-expression networks, we predicted 161 candidate genes (79 cold-responsive genes common to both cultivars and 82 cold-tolerance genes associated with differences in cold tolerance between cultivars) potentially affecting cold response/tolerance, among which 85 (52.80%) were known to be cold-related genes. Moreover, 52 (65.82%) cold-responsive genes (e.g., TIFY11C, LSK1 and LPA) could be confirmed by previous transcriptome studies and 72 (87.80%) cold-tolerance genes (e.g., APX5, OsFbox17 and OsSTA109) were located within QTLs associated with cold tolerance. This study provides an efficient strategy for further discovery of mechanisms of cold tolerance in rice. [ABSTRACT FROM AUTHOR]

1,2,4-trichlorobenzene (1,2,4-TCB) pollution in fields has become a potential threat to rice growth, yet little is known about the different response of many rice cultivars. This study evaluated the 1,2,4-TCB resistance characteristics of 114 generalized rice cultivars by investigating 44 phenotypic and physiological indices across their whole growth periods. Principal component analysis, subordinate function analysis, and cluster analysis were integrated to comprehensively identify 1,2,4-TCB tolerance of rice cultivars for individual as well as whole growth periods. Results demonstrated that the 1,2,4-TCB tolerance of rice was complex and varied with traits, developmental stages, and cultivars. To be specific, 1,2,4-TCB stress decreased rice growth in both seedling and tillering periods. The main resistant responses to 1,2,4-TCB stress were increasing the chlorophyll content, root growth, tiller number and secondary branch number mostly at jointing-booting stage. It implied that the jointing-booting stage was the key period for the development of 1,2,4-TCB resistance in rice. We further classified five groups of rice cultivars according to the levels of 1,2,4-TCB-tolerance based on the comprehensive evaluation value (D) across whole period. We identified 7 high-tolerant, 14 tolerant, 34 moderately tolerant, 44 sensitive and 15 high-sensitive cultivars. Notably, the two high-tolerant cultivars (Nanfan 1604 and Shengdao 2620) showed significant tolerant at individual growth stages, and the five high-sensitive cultivars (Zhongshufengjing 3227, Guang 8 you 165, Ningjing 040, Songzaoxiang 1 and Xindao 22) exhibited sensitivity at individual growth stages, indicating that their tolerance/sensitivity were consistent across the whole growth stages. Finally, one index at seedling stage, five indices at jointing-booting, two indices at heading and four indices at maturity were integrated to measure the tolerance of rice in whole growth periods. The results are useful for evaluating and breeding 1,2,4-TCB-tolerant of rice cultivars, which lay a foundation for further safe rice production in 1,2,4-TCB contaminated paddy soil. [ABSTRACT FROM AUTHOR]

In this paper we consider a breathing circle billiard which is described as a particle that travels inside a time-dependent circular domain and elastically reflecting from the boundary. Between collisions the particle moves with a constant speed along straight lines connecting the collision points. We show that in high energy situation, the dynamics of the system can be studied by constructing an area-preserving monotone twist map. Under appropriate assumptions, it is proved that there exist infinitely many bounded complete orbits, and a large class of periodic and quasi-periodic orbits for the system. This gives a description of the global dynamical behavior of the system. [ABSTRACT FROM AUTHOR]

The aim of quantum metrology is to exploit quantum effects to improve the precision of parameter estimation beyond its classical limit. In this paper, we investigate the quantum parameter estimation problem with multiple channels. It is related but not limited to the following two important and practical quantum metrology problems: (i) Quantum enhanced metrology with control, whose aim is to improve the precision of quantum sensing by utilizing feedback or open-loop control; (ii) Practical quantum metrology where the underlying evolution of quantum probes may change from a unitary dynamics to an open system dynamics, owing to the inevitable decoherence during the quantum sensing operation. For various kinds of quantum multiple channels, the corresponding quantum channel Fisher information is derived. To demonstrate the results, some illustrative examples are given. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

2-(2-Phenylethyl)chromones (PECs) are the principal constituents contributing to the distinctive fragrance of agarwood. How PECs are biosynthesized is currently unknown. In this work, we describe a diarylpentanoid-producing polyketide synthase (PECPS) identified from Aquilaria sinensis. Through biotransformation experiments using fluorine-labeled substrate, transient expression of PECPS in Nicotiana benthamiana, and knockdown of PECPS expression in A. sinensis calli, we demonstrate that the C6–C5–C6 scaffold of diarylpentanoid is the common precursor of PECs, and PECPS plays a crucial role in PECs biosynthesis. Crystal structure (1.98 Å) analyses and site-directed mutagenesis reveal that, due to its small active site cavity (247 Å3), PECPS employs a one-pot formation mechanism including a "diketide-CoA intermediate-released" step for the formation of the C6–C5–C6 scaffold. The identification of PECPS, the pivotal enzyme of PECs biosynthesis, provides insight into not only the feasibility of overproduction of pharmaceutically important PECs using metabolic engineering approaches, but also further exploration of how agarwood is formed. 2-(2-Phenylethyl)chromones (PECs) contribute to the distinctive fragrance of agarwood. Here the authors identify a diarylpentanoid-producing polyketide synthase from Aquilaria sinensis and show how it catalyzes PEC formation. [ABSTRACT FROM AUTHOR]

In this study, protein from Porphyra haitanensis was used as raw material to prepare an antioxidant peptide, and its antioxidant activity was evaluated in vitro. A model of H2O2-induced oxidative damage in HepG2 cells was established, and the effects of Porphyra haitanensis hydrolysates (PHHs) on superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were detected. Finally, the structure of PHHs was identified by ESI-MS/MS. The results showed that the 1,1-diphenyl-2-pyridylhydrazine (DPPH)-free radical-scavenging ability of PHHs was the strongest (59.28% at 1.0 mg mL−1) when hydrolyzed with an acidic protease for 4 h. PHHs with different concentrations had protective effects on H2O2-induced damage to HepG2 cells, and the protective effect was enhanced with increasing concentrations. When the level was 400 µg mL−1, the cell survival rate was as high as 88.62%. Moreover, PHHs can significantly reduce oxidative damage to HepG2 cells by H2O2, improve SOD activity, and reduce MDA content. The tetrapeptide Asp-Lys-Ser-Thr, with a molecular weight of 448 Da, was identified as an important fraction of PHHs by high-resolution mass spectrometry. [ABSTRACT FROM AUTHOR]

The Liulin Spring catchment in Shanxi Province has abundant karst groundwater resources that play a supporting role in the economic and social development of the Lvliang region. Research on the factors controlling the chemical evolution of karst groundwater can be of great significance for the sustainable utilization and effective protection of groundwater resources in the basin. In this study, the major ions of karst groundwater have been studied to identify the hydrogeochemical processes and regional evolution using 29 samples that were collected in 2014 from the recharge area, throughflow area, discharge area and stagnant area of the catchment. The results showed that the temperature and the concentrations of Na+, Ca2+, Mg2+, Cl−, HCO3− and SO42− increased with the increasing distance from the recharge area to the throughflow area, to the discharge area and then to the stagnant area. The chemical composition of karst groundwater in both recharge area and throughflow area was mainly derived from carbonate dissolution, while it was largely controlled by the weathering of silicate minerals in the discharge area, and dominated by the dissolution of both silicates and gypsum in the stagnant areas. The K+, Na+ and Cl− were mainly sourced from the dissolution of salt rock, while the Ca2+, Mg2+, HCO3−, and SO42− were mainly derived from the dissolution of calcite, dolomite, and gypsum. The hydrochemical types of karst groundwater changed from HCO3-Ca • Mg type in the recharge area to HCO3 • SO4-Ca • Mg type in the throughflow area and to HCO3 • SO4-Ca • Na • Mg type in the discharge area, and finally evolved into Cl • HCO3-Na • Ca, Cl • HCO3-Na type and Cl-Na • Ca type in the stagnant area. The results of this study will be useful to effectively guide the sustainable utilization and the integrated planning of water resources in the Liulin Spring catchment. [ABSTRACT FROM AUTHOR]

Objective: To explore the mechanisms of crocin against glycocalyx damage and inflammatory injury in lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) mice and LPS-stimulated human umbilical vein endothelial cells (HUVECs). Methods: Mice were randomly divided into control, LPS, and crocin + LPS (15, 30, and 60 mg/kg) groups. HUVECs were separated into eight groups: control, crocin, matrix metalloproteinase 9 inhibitor (MMP-9 inhib), cathepsin L inhibitor (CTL inhib), LPS, MMP-9 inhib + LPS, CTL inhib + LPS, and crocin + LPS. The potential cytotoxic effect of crocin on HUVECs was mainly evaluated through methylthiazolyldiphenyl-tetrazolium bromide assay. Histological changes were assessed via hemotoxylin and eosin staining. Lung capillary permeability was detected on the basis of wet–dry ratio and through fluorescein isothiocyanate-albumin assay. Then, protein levels were detected through Western blot analysis, immunohistochemical staining, and immunofluorescence. Results: This study showed that crocin can improve the pulmonary vascular permeability in mice with LPS-induced ARDS and inhibit the inflammatory signaling pathways of high mobility group box, nuclear factor κB, and mitogen-activated protein kinase in vivo and in vitro. Crocin also protected against the degradation of endothelial glycocalyx heparan sulfate and syndecan-4 by inhibiting the expressions of CTL, heparanase, and MMP-9 in vivo and in vitro. Overall, this study revealed the protective effects of crocin on LPS-induced ARDS and elaborated their underlying mechanism. Conclusion: Crocin alleviated LPS-induced ARDS by protecting against glycocalyx damage and suppressing inflammatory signaling pathways. [ABSTRACT FROM AUTHOR]

Previous studies have shown that personality types may lead to different health status. The current study aims to refine a previous typological profile of strength using a heterogeneous sample (N = 5776) and clarify further the associations between strength profiles and mental wellbeing (e.g., flourishing), mental illbeing (e.g., depression, anxiety, and stress), strength knowledge, and strength use. Latent profile analysis was implemented to distinguish subgroups on the basis of the three-dimensional inventory of character strengths (e.g., self-control, inquisitiveness, and caring). Results refined previous findings and indicated three specific profiles, namely, Strength, Common, and Risk Groups. The Strength Group scored relatively high on self-control and inquisitiveness but low on caring; the Common Group scored relatively high on caring; and the Risk Group had relatively high scores on self-control. As expected, the Strength Group had the highest strength knowledge and strength use, whereas the Risk Group had the least strength knowledge and strength use. The three proposed profiles have significant differences of anxiety, stress, and flourishing; however, the difference of depression between the Strength and Risk Groups was insignificant compared with the Common Group. This study can be helpful in refining strength typologies for future effective strength-based interventions. [ABSTRACT FROM AUTHOR]

The existing interventional therapy robots for the microwave ablation of liver tumors have a poor clinical applicability with a large volume, low positioning speed and complex automatic navigation control. To solve above problems, a composite configuration interventional therapy robot with passive and active joints is developed. The design of composite configuration reduces the size of the robot under the premise of a wide range of movement, and the robot with composite configuration can realizes rapid positioning with operation safety. The cumulative error of positioning is eliminated and the control complexity is reduced by decoupling active parts. The navigation algorithms for the robot are proposed based on solution of the inverse kinematics and geometric analysis. A simulation clinical test method is designed for the robot, and the functions of the robot and the navigation algorithms are verified by the test method. The mean error of navigation is 1.488 mm and the maximum error is 2.056 mm, and the positioning time for the ablation needle is in 10 s. The experimental results show that the designed robot can meet the clinical requirements for the microwave ablation of liver tumors. The composite configuration is proposed in development of the interventional therapy robot for the microwave ablation of liver tumors, which provides a new idea for the structural design of medical robots. [ABSTRACT FROM AUTHOR]

We investigate electron transport inside a ring system composed of a quantum dot (QD) coupled to two Majorana bound states confined at the ends of a one-dimensional topological superconductor nanowire. By tuning the magnetic flux threading through the ring, the model system we consider can be switched into states with or without zero-energy modes when the nanowire is in its topological phase. We find that the Fano profile in the conductance spectrum due to the interference between bound and continuum states exhibits markedly different features for these two different situations, which consequently can be used to detect the Majorana zero-energy mode. Most interestingly, as a periodic function of magnetic flux, the conductance shows 2 π periodicity when the two Majorana bound states are nonoverlapping (as in an infinitely long nanowire) but displays 4 π periodicity when the overlapping becomes nonzero (as in a finite length nanowire). We map the model system into a QD-Kitaev ring in the Majorana fermion representation and affirm these different characteristics by checking the energy spectrum. [ABSTRACT FROM AUTHOR]

Epoxy composites with biphenyl liquid crystalline polyester (BLCP)-grafted graphene oxides (GO) as inclusions were prepared successfully. The thermal and texture analyses of BLCP were characterized by DSC and POM. The results show that the texture structure of BLCP turned into fan texture from woven texture with increasing temperature and present double texture structure. More importantly, the thermal and mechanical properties of epoxy composites could be improved by incorporating BLCP-grafted GO (BLCP-GO). The epoxy composite with only 0.5 wt% BLCP-GO produced an increase in the initial decomposition temperature ( T ) by 28 °C and glass transition temperature ( T ) by 17.2 °C when compared with the neat epoxy. Moreover, for the mechanical properties tests, the composites with 1.0 wt% BLCP-GO exhibit an increase in impact strength, tensile strength, flexural strength and flexural modulus by 103, 52, 66, and 56 %, respectively, compared with the neat epoxy resin. These excellent performances of the graphene-epoxy composites have a great potential for applications in aerospace and other electrical devices. [ABSTRACT FROM AUTHOR]

Aiming at the fact that distributed multi-channel hybrid network-induced delays and noise interference may deteriorate the control performance of hybrid networked control systems, distributed event-triggered hybrid wired-wireless networked control with $${H_2}/{H_\infty }$$ filtering is proposed. A distributed event-triggered mechanism is firstly employed to reduce communication burden, and two Markov chains are used to respectively describe different characters of network-induced delays of hybrid wired-wireless networks. Then, a $${H_2}/{H_\infty }$$ filter is employed to improve the input signal precision of the controller, where a general closed-feedback filtering and control system model with distributed event-triggered parameters and network-induced delays of hybrid wired-wireless networks is proposed. Furthermore, the designed filter and controller enable the closed-feedback filtering and control system to be stochastic stability and to achieve a prescribed $${H_2}/{H_\infty }$$ performance, and the relationships between the stability criteria and the maximum network-induced delays, distributed event-triggered parameters, the filter and controller parameters and the system performance parameter are established. Finally, simulation results confirm the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Sthenoteuthis oualaniensis is a species of cephalopod that is becoming economically important in the South China Sea. As, Cd, Cr, Cu, Hg, Pb, and Zn concentrations were determined in the mantle, arms, and digestive gland of S. oualaniensis from 31 oceanographic survey stations in the central and southern South China Sea. Intraspecific and interspecific comparisons with previous studies were made. Mean concentrations of trace elements analyzed in arms and mantle were in the following orders: Zn > Cu > Cd > Cr > As > Hg. In digestive gland, the concentrations of Cd and Cu exceed that of Zn. All the Pb concentrations were under the detected limit. [ABSTRACT FROM AUTHOR]

Dispersion stability of nanoparticles in the liquid media is of great importance to the utilization in practice. This study aims to investigate the effects of mechanical dispersion method on the dispersibility of functionalized TiO nanoparticles in the transformer oil. Dispersion methods, including stirring, ultrasonic bath, and probe processes, were systematically tested to verify their versatility for preparing stable nanofluid. The test results reveal that the combination of ultrasonic bath process and stirring method has the best dispersion efficiency and the obtained nanofluid possesses the highest AC breakdown strength. Specifically, after aging for 168 h, the size of nanoparticles in the nanofluid prepared by the combination method has no obvious change, while those obtained by the other three paths are increased obviously. [ABSTRACT FROM AUTHOR]

A plastidic ATP/ADP transporter (AATP) is responsible for importing ATP from the cytosol into plastids. Increasing the ATP supply is a potential way to facilitate anabolic synthesis in heterotrophic plastids of plants. In this work, a gene encoding the AATP protein, named SlAATP, was successfully isolated from tomato. Expression of SlAATP was induced by exogenous sucrose treatment in tomato. The coding region of SlAATP was cloned into a binary vector under the control of 35S promoter and then transformed into Arabidopsis to obtain transgenic plants. Constitutive expression of SlAATP significantly increased the starch accumulation in the transgenic plants. Real-time quantitative PCR (qRT-PCR) analysis showed that constitutive expression of StAATP up-regulated the expression of phosphoglucomutase ( AtPGM), ADP-glucose pyrophosphorylase ( AtAGPase), granule-bound starch synthase ( AtGBSS I and AtGBSS II), soluble starch synthases ( AtSSS I, AtSSS II, AtSSS III and AtSSS IV) and starch branching enzyme ( AtSBE I and AtSBE II) genes involved in starch biosynthesis in the transgenic Arabidopsis plants. Meanwhile, enzymatic analyses indicated that the major enzymes (AGPase, GBSS, SSS and SBE) involved in the starch biosynthesis exhibited higher activities in the transgenic plants compared to the wild-type (WT). These findings suggest that SlAATP may improve starch content of Arabidopsis by up-regulating the expression of the related genes and increasing the activities of the major enzymes invovled in starch biosynthesis. The manipulation of SlAATP expression might be used for increasing starch accumulation of plants in the future. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate whether metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) can be used as a potential therapy target for human esophageal squamous cell carcinoma. MALAT-1 expression levels were detected in 137 paired EC samples and adjacent nonneoplastic tissues. Human esophageal carcinoma cell lines EC9706 and KYSE150 were transfected with MALAT-1 small interference RNA. Cell proliferation, migration/invasion ability, cell cycle, and apoptosis were assessed. MALAT-1 expressed higher levels in esophageal cancer tissues when compared with paired adjacent normal tissues. This high expression was associated with a decreased survival rate. MALAT-1 knockdown induced a decrease in proliferation-enhanced apoptosis, inhibited migration/invasion, and reduced colony formation and led to cell cycle arrest at the G2/M phase. These data indicates that MALAT-1 could be exploited for therapeutic benefit. [ABSTRACT FROM AUTHOR]

In order to compensate for the weaknesses of the sensory evaluation method for the quality of crisp grass carp fish and to establish an objective and practical method based on instrumental texture analysis, two experiments were carried out: (1) tracking the quality evolution of crisp grass carp during the whole culture period with both instrumental analysis and sensory evaluation in order to find out which instrumental texture parameter make greater contribution to the formation of crisp, compact quality and (2) determining the quality of crisp grass carp in different markets to investigate the real quality distribution and then grading the quality based on this survey with method of cluster analysis. Results showed that the instrumental hardness and chewiness of crisp grass carp showed a significant correlation with its sensory crispness evaluation and made greater contribution to the formation of quality characteristics of crisp grass carp than the instrumental springiness and instrumental cohesiveness. So, the quality of crisp grass carp was finally classified into three grades based on the instrumental hardness and the instrumental chewiness with method of cluster analysis. [ABSTRACT FROM AUTHOR]

The graphene oxide (GO) sheets are chemically grafted with γ-etheroxygentrimethoxysilane (KH560) and liquid crystalline epoxy (LCE) is synthesized from 4,4′-bis(2-hydroxyhexoxy)biphenyl (BP) and epichlorohydrin before being incorporated into epoxy matrix. Then we present a novel approach to the fabrication of advanced polymer composites from epoxy matrix by incorporation of two modifiers, which are grafted GO (g-GO) and LCE. The mechanical properties of epoxy composites are greatly improved by incorporating LCE/g-GO hybrid fillers. For instance, the addition of 3 wt% hybrid filler (2 wt% g-GO and 1 wt% LCE) into the epoxy matrix resulted in the increases in impact strength by 132.6 %, tensile strength by 27.6 % and flexural strength by 37.5 %. Moreover, LCE/g-GO hybrid fillers are effective to increase thermal decomposition temperature, glass transition temperature, and storage modulus by strong affinity between the fillers and epoxy matrix. [ABSTRACT FROM AUTHOR]

The effect of two alkylpyridinium ionic liquids (py-iLs) including N-butylpyridinium hydrogen sulfate (BpyHSO) and N-hexylpyridinium hydrogen sulfate (HpyHSO) on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on Cu electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope (SEM) and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of (111), (200) and (311) planes. [ABSTRACT FROM AUTHOR]

Quantum key distribution (QKD) provides the only intrinsically unconditional secure method for communication based on the principle of quantum mechanics. Compared with fibre-based demonstrations, free-space links could provide the most appealing solution for communication over much larger distances. Despite significant efforts, all realizations to date rely on stationary sites. Experimental verifications are therefore extremely crucial for applications to a typical low Earth orbit satellite. To achieve direct and full-scale verifications of our set-up, we have carried out three independent experiments with a decoy-state QKD system, and overcome all conditions. The system is operated on a moving platform (using a turntable), on a floating platform (using a hot-air balloon), and with a high-loss channel to demonstrate performances under conditions of rapid motion, attitude change, vibration, random movement of satellites, and a high-loss regime. The experiments address wide ranges of all leading parameters relevant to low Earth orbit satellites. Our results pave the way towards ground-satellite QKD and a global quantum communication network. [ABSTRACT FROM AUTHOR]

In this letter, we propose an improved Quasi-orthogonal space-time block code (QOSTBC) with full rate, full diversity, linear decoding and better peak-to-average power ratio (PAPR). Constellation rotation is used to the input symbol vector to ensure full diversity, and then the information symbol vector is interleaved in coordinates and pre-grouped by using a Given rotation matrix. The performance is evaluated by numerical experiments. The PAPR of our proposed QOSTBC is lower than that of CI-QOSTBC in Khan and Rajan (IEEE Trans Inf Theory 52(5):2062-2091, ). Meanwhile, the Bit-error-rate versus Signal-to-noise-ratio of our proposed QOSTBC is better than those of OSTBC (Tarokh et al. in IEEE Trans Inf Theory 45(5):1456-1467, ) QOSTBC (Jafarkhani in IEEE Trans Wirel Commun 49(1):1-4, ), G-QOSTBC (Park et al. in IEEE Commun Lett 12(12):868-870, ), slightly better that of the CI-QOSTBC, and as same as that of the recently proposed Minimum Decoding Complexity QOSTBCs (MDC-QOSTBC) in Yuen et al.(IEEE Trans Wirel Commun 4(5):2089-2098, ), Wang and Xia (IEEE Trans Inf Theory 55(3):1104-1130, ). Compared with MDC-QOSTBC, the proposed QOSTBC has simpler code construct and lower decoding complexity. [ABSTRACT FROM AUTHOR]

The stability of ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO) during zinc electrowinning from acidic sulfate solution was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. Compared with the traditional industrial additives, gelatine and gum arabic, [BMIM]HSO has more excellent chemical and thermal stabilities. The inhibition effects of gelatine and gum arabic on the zinc electrocrystallization are observed to markedly weaken due to their part degradation after 12 h longtime successive electrolysis and high temperature (90 °C) treatments. In contrast, the activity of [BMIM]HSO is practically unaffected after 24 h longtime successive electrolysis and high temperature treatments. These results are corroborated with the corresponding morphological analysis of the cathodic deposits. [ABSTRACT FROM AUTHOR]

ALKBH2 is a direct DNA repair dioxygenase guarding the mammalian genome against N1-methyladenine, N3-methylcytosine and 1,N6-ethenoadenine damage. A prerequisite for repair is to identify these lesions in the genome. Here we present crystal structures of human ALKBH2 bound to different duplex DNAs. Together with computational and biochemical analyses, our results suggest that DNA interrogation by ALKBH2 has two previously unknown features: (i) ALKBH2 probes base-pair stability and detects base pairs with reduced stability, and (ii) ALKBH2 does not have nor need a damage-checking site, which is critical for preventing spurious base cleavage for several glycosylases. The demethylation mechanism of ALKBH2 insures that only cognate lesions are oxidized and reversed to normal bases, and that a flipped, non-substrate base remains intact in the active site. Overall, the combination of duplex interrogation and oxidation chemistry allows ALKBH2 to detect and process diverse lesions efficiently and correctly. [ABSTRACT FROM AUTHOR]

Paraoxonase is an HDL-associated enzyme that plays a preventive role against oxidative stress, which is thought to contribute to cancer development. PON1 activity varies widely among individuals, which is in part related to two common nonsynonymous polymorphisms in the PON1 gene (Q192R and L55M). The polymorphisms in PON1 have been implicated in cancer risk. However, results from the studies to date have been conflicting. To clarify the association, a meta-analysis was performed for 7,073 cases and 9,520 controls from 25 published case-control studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. Significant associations between PON1-L55M but not Q192R polymorphism and total cancer were observed from all the comparisons. In stratified analyses, PON1-55M allele was a risk factor for breast cancer. Similarly, increased risk was observed for prostate cancer (OR = 1.18, 95% CI: 1.01-1.36, P = 0.260) and Caucasian population (OR = 1.18, 95% CI: 1.02-1.38, P = 0.1) of the LM genotype, compared with the LL genotype. For PON1-Q192R polymorphism, PON1-192R allele was a decreased risk factor for cancer in the Asian group (RR vs QQ: OR = 0.61, 95% CI: 0.38-0.98, P = 0.268; QR vs QQ: OR = 0.71, 95% CI: 0.52-0.96, P = 0.130; RR + QR vs QQ: OR = 0.71, 95% CI: 0.53-0.95, P = 0.135). Although some modest bias could not be eliminated, this meta-analysis suggests that the PON1- 55M allele is a risk factor for the development of cancer, in particular for breast cancer. Future studies with larger sample sizes are warranted to further evaluate these associations. [ABSTRACT FROM AUTHOR]

The mechanical performance of a flexible riser is more outstanding than other risers in violent environmental conditions. Based on the lumped mass method, a steep wave flexible riser configuration attached to a Floating Production Storage and Offloading (FPSO) has been applied to a global analysis in order to acquire the static and dynamic behavior of the flexible riser. The riser was divided into a series of straight massless line segments with a node at each end. Only the axial and torsional properties of the line were modeled, while the mass, weight, and buoyancy were all lumped to the nodes. Four different buoyancy module lengths have been made to demonstrate the importance of mode selection, so as to confirm the optimum buoyancy module length. The results in the sensitivity study show that the flexible riser is not very sensitive to the ocean current, and the buoyancy module can reduce the Von Mises stress and improve the mechanical performance of the flexible riser. Shorter buoyancy module length can reduce the riser effective tension in a specific range of the buoyancy module length when other parameters are constant, but it can also increase the maximum curvature of the riser. As a result, all kinds of the riser performances should be taken into account in order to select the most appropriate buoyancy module length. [ABSTRACT FROM AUTHOR]

The nature of the quantum trajectories, described by stochastic master equations, may be jump-like or diffusive, depending upon different measurement processes. There are many different unravelings corresponding to different types of stochastic master equations for a given master equation. In this paper, we study the relationship between the quantum stochastic master equations and the quantum master equations in the Markovian case under feedback control. We show that the corresponding unraveling no longer exists when we further consider feedback control besides measurement. It is due to the fact that the information gained by the measurement plays an important role in the control process. The master equation governing the evolution of ensemble average cannot be restored simply by eliminating the noise term unlike the case without a control term. By establishing a fundamental limit on performance of the master equation with feedback control, we demonstrate the differences between the stochastic master equation and the master equation via theoretical proof and simulation, and show the superiority of the stochastic master equation for feedback control. [ABSTRACT FROM AUTHOR]

A novel method for laser beam straightness error measurements based on common-path compensation is proposed. The basic principle of the method is described and the math-model is established. Furthermore, the influence of laser beam drift on straightness error measurements is analyzed. The experimental results show that the measurement accuracy can be greatly improved by using the common-path compensation for laser beam drift. [ABSTRACT FROM AUTHOR]

The effects of temperature and current density on cathodic current efficiency, specific energy consumption, and zinc deposit morphology during zinc electrodeposition from sulfate electrolyte in the presence of 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO4) as additive were investigated. The highest current efficiency (93.7%) and lowest specific energy consumption (2,486 kWh t−1) were achieved at 400 A m−2 and 313 K with addition of 5 mg dm−3 [BMIM]HSO4. In addition, the temperature dependence of some kinetic parameters for the zinc electrodeposition reaction was experimentally determined. Potentiodynamic polarization sweeps were carried out to obtain the expression for each parameter as a function of temperature. In the condition studied, the exchange current density depended on temperature as ln( i0) = − a/ T + b and the charge transfer coefficient was constant. Moreover, the adsorption of the additive on cathodic surface obeyed the Langmuir adsorption isotherm. The associated thermodynamic parameters indicated the adsorption to be chemical. [ABSTRACT FROM AUTHOR]

The efficacy of radiotherapy prior to surgery for the treatment of maxillofacial tumours is compared with and without sensitization with haematoporphyrin derivative (HPD). Residual tumour was found in the resected tissue in 92% of unsensitized but only 52% of sensitized cases, suggesting considerable enhancement of tumour destruction by use of the HPD. [ABSTRACT FROM AUTHOR]

Adaptive techniques have great potential for wide application in enhancing the precision of quantum parameter estimation. We present an adaptive quantum state tomography protocol for finite dimensional quantum systems and experimentally implement the adaptive tomography protocol on two-qubit systems. In this adaptive quantum state tomography protocol, an adaptive measurement strategy and a recursive linear regression estimation algorithm are performed. Numerical results show that our adaptive quantum state tomography protocol can outperform tomography protocols using mutually unbiased bases and the two-stage mutually unbiased bases adaptive strategy, even with the simplest product measurements. When nonlocal measurements are available, our adaptive quantum state tomography can beat the Gill–Massar bound for a wide range of quantum states with a modest number of copies. We use only the simplest product measurements to implement two-qubit tomography experiments. In the experiments, we use error-compensation techniques to tackle systematic error due to misalignments and imperfection of wave plates, and achieve about a 100-fold reduction of the systematic error. The experimental results demonstrate that the improvement of adaptive quantum state tomography over nonadaptive tomography is significant for states with a high level of purity. Our results also show that this adaptive tomography method is particularly effective for the reconstruction of maximally entangled states, which are important resources in quantum information. Quantum tomography: Adaptivity improves precision Quantum state tomography is an essential task in the development of quantum technology. The key problem is to find a strategy that has a high level of estimation accuracy and is easy to experimentally implement. A group of international scientists from China and Australia presented, and experimentally tested, such a strategy, called recursively adaptive quantum state tomography (RAQST). In RAQST, no prior assumption on the state is made. Numerical results show that RAQST, even with the simplest product measurements, outperforms other proposed protocols wherein nonlocal measurements are involved. With error-compensation techniques, the authors experimentally demonstrated its superiority for two-qubit optical tomography. RAQST is particularly effective when reconstructing states with high purity, which are important resources in quantum information. Their method offers a new basis for designing effective approaches for determining a quantum state and can be widely used in quantum information experiments. [ABSTRACT FROM AUTHOR]

Superconducting quantum systems are promising candidates for quantum information processing due to their scalability and design flexibility. However, the existence of defects, fluctuations, and inaccuracies is unavoidable for practical superconducting quantum circuits. In this paper, a sampling-based learning control (SLC) method is used to guide the design of control fields for manipulating superconducting quantum systems. Numerical results for one-qubit systems and coupled two-qubit systems show that the 'smart' fields learned using the SLC method can achieve robust manipulation of superconducting qubits, even in the presence of large fluctuations and inaccuracies. [ABSTRACT FROM AUTHOR]