4,388 research outputs found
Improved mechanical and electrical properties in electrospun polyimide/multiwalled carbon nanotubes nanofibrous composites
Highly aligned polyimide (PI) and PI/multi-walled carbon nanotubes (PI/MWCNTs) nanofibrous composites by incorporating poly(ethylene oxide) as the dispersing medium were fabricated using electrospinning technique. The morphology, mechanical, and electrical properties of the electrospun nanofibrous composites were investigated. Scanning electron microscope showed that the functionalized MWCNTs (f-MWCNTs) were well dispersed and oriented along the nanofiber axis. Analysis of electrical properties indicated a remarkable improvement on the alternating current conductivity by introduction of the aligned f-MWCNTs. Besides, with addition of 3 vol.% f-MWCNTs, the obvious enhancement of tensile modulus and strength was achieved. Thus, the electrospun PI/MWCNTs nanofibrous composites have great potential applications in multifunctional engineering materials
2-[1-(4-Chlorobenzoyl)pyrrolidin-2-yl]-4,4,5,5-tetramethyl-4,5-dihydroimidazole-1-oxyl-3-oxide
In the title compound, C18H23ClN3O3, the imidazole ring system has an envelope conformation, whereas the nitronyl nitroxide unit displays a half-chair or twisted conformation. In the crystal, C—H⋯O hydrogen bonds build up a three-dimensional network
Sex-Specific Correlations of Individual Heterozygosity, Parasite Load, and Scalation Asymmetry in a Sexually Dichromatic Lizard
Heterozygosity-fitness correlations (HFCs) provide insights into the genetic bases of individual fitness variation in natural populations. However, despite decades of study, the biological significance of HFCs is still under debate. In this study, we investigated HFCs in a large population of the sexually dimorphic lizard Takydromus viridipunctatus (Lacertidae). Because of the high prevalence of parasitism from trombiculid mites in this lizard, we expect individual fitness (i.e., survival) to decrease with increasing parasite load. Furthermore, because morphological asymmetry is likely to influence individuals\u27 mobility (i.e., limb asymmetry) and male biting ability during copulation (i.e., head asymmetry) in this species, we also hypothesize that individual fitness should decrease with increasing morphological asymmetry. Although we did not formally test the relationship between morphological asymmetry and fitness in this lizard, we demonstrated that survival decreased with increasing parasite load using a capture-mark-recapture data set. We used a separate sample of 140 lizards to test the correlations between individual heterozygosity (i.e., standardized mean d2 and HL based on 10 microsatellite loci) and the two fitness traits (i.e., parasite load and morphological asymmetry). We also evaluated and excluded the possibility that single-locus effects produced spurious HFCs. Our results suggest male-only, negative correlations between individual heterozygosity and parasite load and between individual heterozygosity and asymmetry, suggesting sex-specific, positive HFCs. Male T. viridipunctatus with higher heterozygosity tend to have lower parasite loads (i.e., higher survival) and lower asymmetry, providing a rare example of HFC in reptiles
Self-reported Evaluation of Psychosocial Effects of Fluorosis among Inhabitants Living in a Rural Fluorosis Epidemic Area in China: Psychosocial Effects of Dental Fluorosis
Objective: The purpose of this study was to investigate the psychosocial effects of fluorosis on the patients in the fluorosis epidemic area. Methods: In the rural fluorosis epidemic areas in Hebei province of China, 416 inhabitants were randomly selected to be examined using Dean’s Index (DI). Surface Index of Fluorosis (TSIF) was used in 178 recruited participants who were also involved in a psychosocial questionnaire investigation. Demographic information and six five-point subscales about “Attitude to Teeth”, “Index of Well-Being”, “Index of General Affect”, “Interaction Anxiousness Scale” (IAS), “Self-Esteem Scale” (SES) and “Impact on Behavior” were included in the questionnaire. SPSS12.0 software was used to analyze the data
Investigating the use of a hybrid plasmonic–photonic nanoresonator for optical trapping using finite-difference time-domain method
We investigate the use of a hybrid nanoresonator comprising a photonic crystal (PhC) cavity coupled to a plasmonic bowtie nanoantenna (BNA) for the optical trapping of nanoparticles in water. Using finite difference time-domain simulations, we show that this structure can confine light to an extremely small volume of ~30,000 nm3 (~30 zl) in the BNA gap whilst maintaining a high quality factor (5400–7700). The optical intensity inside the BNA gap is enhanced by a factor larger than 40 compared to when the BNA is not present above the PhC cavity. Such a device has potential applications in optical manipulation, creating high precision optical traps with an intensity gradient over a distance much smaller than the diffraction limit, potentially allowing objects to be confined to much smaller volumes and making it ideal for optical trapping of Rayleigh particles (particles much smaller than the wavelength of light)
A User-Centered Mapping Design for Geomorphological Hazard Thematic Map
Numerous studies have concentrated on developing user-centered designs for hazard zone maps but rarely for hazard-oriented geomorphological maps, named as Geomorphological Hazard Thematic Maps (GHTMs) in this study, which provide more detailed information about natural hazards. This study developed a user-centered mapping design for GHTMs for nonexperts in geomorphology. We invited civil engineers and high school educators to evaluate a sample GHTM\u27s design in group and focus group panel interviews. The civil engineers preferred maps with more geomorphological features, whereas the educators preferred simple designs. Both groups indicated that the inclusion of essential facilities and road networks is essential. The map was also adjusted by adding hillshade layer and by changing the symbology for mass wasting, fault scarps, and fluvial features to increase clarity and simplicity. This case study is the first step toward developing user-centered mapping designs for hazard communication that will deepen their understanding of natural hazards
First fossil frog and snake assemblage from southern Taiwan: a window into Pleistocene herpetofauna and palaeoenvironments in subtropical East Asia
Herpetofauna, particularly amphibians and reptiles, exhibit high levels of endemism and distinct diversity pattern on Taiwan island. However, the biogeographic history of these groups remains obscure, in part due to the lack of a herpetofaunal fossil record. Here, we report the first fossil record of frogs and snakes from Taiwan, based on Middle Pleistocene vertebrate assemblage recovered from the Chochen–Tsailiao area in southern Taiwan. The collection includes a vertebra of a bufonid frog and multiple vertebrae of colubrid and viperid snakes. Despite their fragmentary preservation, several vertebrae are identifiable, including a toad (Duttaphrynus melanostictus), rat snakes (Ptyas mucosa and P. cf. mucosa), a wolf snake (Lycodon rufozonatum), and a pit viper (Protobothrops sp.). Additional vertebrae are attributed to Colubridae indet. and Alethinophidia indet. The preservation of these delicate skeletal elements in a tectonically active and humid subtropical setting highlights the exceptional nature of this discovery. Palaeoenvironmental reconstruction based on ecological preferences of extant analogues suggests that the region supported a humid fluvial and open woodland environment with abundant water bodies
A Security-Awareness Virtual Machine Management Scheme Based on Chinese Wall Policy in Cloud Computing
Cloud computing gets increasing attention for its capacity to leverage developers from infrastructure management tasks. However, recent works reveal that side channel attacks can lead to privacy leakage in the cloud. Enhancing isolation between users is an effective solution to eliminate the attack. In this paper, to eliminate side channel attacks, we investigate the isolation enhancement scheme from the aspect of virtual machine (VM) management. The security-awareness VMs management scheme (SVMS), a VMs isolation enhancement scheme to defend against side channel attacks, is proposed. First, we use the aggressive conflict of interest relation (ACIR) and aggressive in ally with relation (AIAR) to describe user constraint relations. Second, based on the Chinese wall policy, we put forward four isolation rules. Third, the VMs placement and migration algorithms are designed to enforce VMs isolation between the conflict users. Finally, based on the normal distribution, we conduct a series of experiments to evaluate SVMS. The experimental results show that SVMS is efficient in guaranteeing isolation between VMs owned by conflict users, while the resource utilization rate decreases but not by much
- …
