46 research outputs found

    Waveform-Controlled Terahertz Radiation from the Air Filament Produced by Few-Cycle Laser Pulses

    Full text link
    Waveform-controlled Terahertz (THz) radiation is of great importance due to its potential application in THz sensing and coherent control of quantum systems. We demonstrated a novel scheme to generate waveform-controlled THz radiation from air plasma produced when carrier-envelope-phase (CEP) stabilized few-cycle laser pulses undergo filamentation in ambient air. We launched CEP-stabilized 10 fs-long (~ 1.7 optical cycles) laser pulses at 1.8 {\mu}m into air and found that the generated THz waveform can be controlled by varying the filament length and the CEP of driving laser pulses. Calculations using the photocurrent model and including the propagation effects well reproduce the experimental results, and the origins of various phase shifts in the filament are elucidated.Comment: 5pages, 5 figure

    Biologically Inspired Design of Context-Aware Smart Products

    Get PDF
    The rapid development of information and communication technologies (ICTs) and cyber–physical sys-tems (CPSs) has paved the way for the increasing popularity of smart products. Context-awareness isan important facet of product smartness. Unlike artifacts, various bio-systems are naturally characterizedby their extraordinary context-awareness. Biologically inspired design (BID) is one of the most commonlyemployed design strategies. However, few studies have examined the BID of context-aware smart prod-ucts to date. This paper presents a structured design framework to support the BID of context-awaresmart products. The meaning of context-awareness is defined from the perspective of product design.The framework is developed based on the theoretical foundations of the situated function–behavior–structure ontology. A structured design process is prescribed to leverage various biological inspirationsin order to support different conceptual design activities, such as problem formulation, structure refor-mulation, behavior reformulation, and function reformulation. Some existing design methods and emerg-ing design tools are incorporated into the framework. A case study is presented to showcase how thisframework can be followed to redesign a robot vacuum cleaner and make it more context-aware.Ó2019 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering andHigher Education Press Limited Company. This is an open access article under the CC BY-NC-ND licens

    Cancer type-specific modulation of mitochondrial haplogroups in breast, colorectal and thyroid cancer

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Mitochondrial DNA (mtDNA) haplogroups and single nucleotide polymorphisms (mtSNP) have been shown to play a role in various human conditions including aging and some neurodegenerative diseases, metabolic diseases and cancer.</p> <p>Methods</p> <p>To investigate whether mtDNA haplogroups contribute to the occurrence of cancer in a specific Chinese population, we have carried out a comprehensive case-control study of mtDNA from large cohorts of patients with three common cancer types, namely, colorectal cancer (n = 108), thyroid cancer (n = 100) and breast cancer (n = 104), in Wenzhou, a southern Chinese city in the Zhejiang Province.</p> <p>Results</p> <p>We found that patients with mtDNA haplogroup M exhibited an increased risk of breast cancer occurrence [OR = 1.77; 95% CI (1.03-3.07); P = 0.040], and that this risk was even more pronounced in a sub-haplogroup of M, D5 [OR = 3.11; 95%CI (1.07-9.06); p = 0.030]. In spite of this, in patients with breast cancer, haplogroup M was decreased in the metastatic group. On the other hand, our results also showed that haplogroup D4a was associated with an increased risk of thyroid cancer [OR = 3.00; 95%CI (1.09-8.29); p = 0.028]. However, no significant correlation has been detected between any mtDNA haplogroups and colorectal cancer occurrence.</p> <p>Conclusion</p> <p>Our investigation indicates that mitochondrial haplogroups could have a tissue-specific, population-specific and stage-specific role in modulating cancer development.</p

    Embankment seismic fragility assessment: A case study on Xi'an-Baoji expressway (China).

    No full text
    Although embankment seismic damages are very complex, there has been little seismic fragility research yet. Researches on seismic fragility of bridges, dams and reinforced concrete (RC) structures have achieved fruitful results, which can provide references for embankment seismic fragility assessment. Meanwhile, the influencing degrees of retaining structures, such as retaining walls on the embankment seismic performances are still unclear. The K1025+470 embankment of the Xi'an-Baoji expressway was selected as the research object, and the finite difference models of the embankment fill-soil foundation system and embankment fill-soil foundation-retaining wall system were established. The ground-motion records for Incremental Dynamic Analysis (IDA) were selected and the dynamic response analysis were conducted. Probabilistic Seismic Demand Analysis (PSDA) was used to deal with the IDA results and the seismic fragility curves were generated. Based on the assessment results, the influences of the retaining wall on the embankment seismic fragility were further verified. The research results show that regardless of which seismic damage parameter is considered or the presence or absence of the retaining wall, larger PGAs always correspond to higher probabilities of each seismic damage grade. Seismic damages to the embankment fill-soil foundation-retaining wall system are always lower than those of the embankment fill-soil foundation system under the same PGA actions, thus, the retaining wall can decrease the embankment seismic fragility significantly

    Production, purification and cytotoxity of soluble human Fas ligand expressed by Escherichia coli and Dictyostelium discoideum

    No full text
    Human Fas ligancl (hFasL) is a type II membrane protein that induces apoptosis in the Fas-bearing cells. Its special biological activity has the potential for the therapeutic use as an anti-cancer agent directed at enhancing apoptosis in tumor cells. In this study Escherichia coli and eukaryotic Dictyostelium discoideum were used to produce a soluble form of hFasL in large amounts. An expression vector for hFasL production in E. coli was constructed based on plasmid pET32a(+). By cultivation of the hFasL-producing E. coli clone on LB medium and induction with IPTG, a hFasL concentration of 1.0 mg L-1 was achieved. D. discoideum strain AX3-hFasL-H was cultured in a conventional stirred bioreactor on an improved synthetic medium using a simple fed-batch strategy, and cell densities of up to 8.3 x 10(7) cells/mL and a maximum hFasL concentration of 420 mu g/L were obtained. Using Ni-NTA affinity chromatography purification, two kinds of recombinant hFasLs from E. coli and D. discoideum were purified with a purity of 94% and 90%, respectively. They showed similar biological activities in inducing apoptosis in Fas-expressing cells. (C) 2012 Elsevier B.V. All rights reserved.Program for New Century Excellent Talents in Fujian Province, PR China; National Natural Science Foundation of China [31071488, 20736008, 20928006

    The impulsive online shopper: effects of COVID-19 burnout, uncertainty, self-control, and online shopping trust

    No full text
    Abstract Consumerism during the COVID-19 pandemic has been characterized by impulsive buying. Using the theoretical lens of uncertainty avoidance and ego-depletion to identify the mediating mechanisms and moderating factors for online impulse buying, we surveyed young consumers across two relevant periods for high consumerism—the week preceding the 2021 Chinese Spring Festival (Study 1; February 4–9, 2021, n = 1495) and the weeks during and after the festival (Study 2; February 12 to March 2, 2021, n = 923). Perception of COVID-19 variant uncertainty was both directly and indirectly (via online shopping trust) positively associated with online impulse buying. COVID-19 burnout was consistently indirectly associated with online impulse buying via self-regulation and self-appraised impulsivity but inconsistently directly associated. Self-regulation was surprisingly positively associated with online impulse buying, possibly reflecting evidence of already depleted resources from prolonged regulatory exertion among high self-regulators. Self-appraised impulsivity negatively interacted with perception of COVID-19 variant uncertainty, suggesting that as trait impulsivity increases, individuals are less incentivized by peripheral drivers of online impulse buying
    corecore