11,241 research outputs found
Location verification for future wireless vehicular networks: Research directions and challenges
No full textVehicle location information obtained through the global navigation satellite system (GNSS) will play a pivotal role in emerging vehicular networks. This vital information is, however, susceptible to a host of unwanted manipulations, especially if a malicious entity is involved. The most obvious example of such manipulations is the forwarding by a malicious vehicle of false GNSS locations to other members of the network. Such events can lead to poor operational outcomes for the vehicular network, and in extreme cases even lead to catastrophic safety violations. Here, we highlight research efforts pursued in the past few years that have attempted to address this weakness in vehicular networks. We also discuss the importance of location verification in the wake of emerging wireless technologies, such as those being proposed for beyond 5G (B5G) wireless vehicular networks. In particular, we detail an opportunity to conduct location reporting and verification simultaneously with the aid of mmWave technology and discuss how emerging machine learning (ML) techniques will provide for location verification solutions where reliability levels will be commensurate with that required by the vehicular network paradigm. We close by discussing the potential enhancements for location verification within a future combined B5G-ML architecture
Effects of Exogenous Melatonin on Sun-Compass Orientation of Homing Pigeons
No full textExperiments were performed to test whether melatonin plays a role in sun-compass orientation of homing pigeons. Birds were kept for a period of time in dim continuous light (LL) or in artificial light-dark (LD) cycles and then released under the sun from unfamiliar sites. Control birds in dim LL were oriented homeward in all cases. Birds with melatonin implants in LD were capable of a correct use of the sun compass at release. Birds with melatonin implants in dim LL, on the contrary, performed very poorly in orientation. The present results demonstrate for the first time that melatonin is involved in the control of the circadian rhythms underlying sun-compass orientation in birds. © 1990, Sage Publications. All rights reserved
Natalia LL - artystka neoawangardowa
No full textThe paper shows Natalia Lach-Lachowicz (Natalia LL) as a neo avant-garde artist whose works in a specific maximalistic way are very close to the main currents of avant-garde trends: new mediality (photography), minimalism, conceptualism, performance, bodyart, pop-art, and feminist art. The author of the article concentrates mainly on the mutual influences of conceptualism, consumptionism, and feminism in Natalia LL’s works and pays attention to the emancipatory potential of her works of the seventies and the eighties
Pier and Sun Pavilion
No full textChildren play on beach in front of Pine Avenue Pier, built in 1893. The original Pavilion, built in 1899, was built on the shore side of the Pier. When it was destroyed by fire in 1904, Long Beach built the Sun Pavilion at the far end of the Pier. It was supposed to be a temporary structure, but it remained in operation for thirty years. Note on photograph notes: 'Copyright 1905 by G. C. Hovey
.'ll: 'by G. C. Hove
Transmembrane Pores Formed by Human Antimicrobial Peptide LL-37
No full textAbstractHuman LL-37 is a multifunctional cathelicidin peptide that has shown a wide spectrum of antimicrobial activity by permeabilizing microbial membranes similar to other antimicrobial peptides; however, its molecular mechanism has not been clarified. Two independent experiments revealed LL-37 bound to membranes in the α-helical form with the axis lying in the plane of membrane. This led to the conclusion that membrane permeabilization by LL-37 is a nonpore carpet-like mechanism of action. Here we report the detection of transmembrane pores induced by LL-37. The pore formation coincided with LL-37 helices aligning approximately normal to the plane of the membrane. We observed an unusual phenomenon of LL-37 embedded in stacked membranes, which are commonly used in peptide orientation studies. The membrane-bound LL-37 was found in the normal orientation only when the membrane spacing in the multilayers exceeded its fully hydrated value. This was achieved by swelling the stacked membranes with excessive water to a swollen state. The transmembrane pores were detected and investigated in swollen states by means of oriented circular dichroism, neutron in-plane scattering, and x-ray lamellar diffraction. The results are consistent with the effect of LL-37 on giant unilamellar vesicles. The detected pores had a water channel of radius 23–33 Å. The molecular mechanism of pore formation by LL-37 is consistent with the two-state model exhibited by magainin and other small pore-forming peptides. The discovery that peptide-membrane interactions in swollen states are different from those in less hydrated states may have implications for other large membrane-active peptides and proteins studied in stacked membranes
(An) experiment with LL(1) parser
No full text학위논문 (석사) - 한국과학기술원 : 전산학과, 1979.2, [ [2], 42, vii p. ]The aim of this thesis is to experiment and implement a practical high level language compiler using LL(1) parser.
The programming language pl/O is selected for experiment. Implementation of PL/O compiler is explained as follows:
(1) Description of syntax analysis containing lexical scanning, parsing, and error recovery
(2) Design of PL/O machine and code generation
(3) Translation of PL/O code into 8080 assembly language.한국과학기술원 : 전산학과
LL-37 expression in the skin in systemic lupus erythematosus
No full text The objective of this study was to investigate the expression and relationship of LL-37, plasmacytoid dendritic cells (pDCs) and interferon-alpha (IFN-α) in skin in systemic lupus erythematosus (SLE), and their role in SLE pathogenesis. Skin biopsies were taken from nine SLE patients and six healthy volunteers. Expression of LL-37, pDCs and IFN-α in skin specimens and consecutive sections of skin was detected with an immunohistochemical technique (IH); the expression of LL-37 and pDCs in the samples was detected with in situ hybridization (ISH). The expression levels of LL-37, pDCs and IFN-α were significantly higher in SLE skin than in that of healthy controls ( p < 0.001) with either the IH or the ISH technique, and the location of positive expression in consecutive sections was similar. Correlation analysis showed that the expression levels of LL-37, pDCs and IFN-α correlated positively with each other. In conclusion, the expression of LL-37, pDCs and IFN-α was increased in the skin of patients with active SLE. It is necessary to study further the role of LL-37 in the pathogenesis of SLE, and the exact relationship among LL-37, pDCs and IFN-α. </jats:p
Vitamin D and LL-37 in children with pneumonia
No full textBackground: Vitamin D is involved in the regulation of about1000 human genes. Recent studies suggest that vitamin D may have other actions outside of its classic functions related to bone and calcium homeostasis. The only human cathelicidin, LL 37, enhances microbial killing against a broad range of respiratory pathogens and has a defined vitamin D- dependent mechanism. Objective: evaluate the association between vitamin D status and plasma LL-37 levels in children with pneumonia. Study design: Forty consecutive children admitted to the chest unit of the Pediatric Department of Zagazig University Hospital with proven diagnosis of pneumonia were included in the study. They were 22 males and 18 females, of ages ranging from 2 to 5 years. In addition, 40 age and sex matched apparently healthy children served as a control group. A verbal consent was obtained from parent(s) of each child before inclusion to the study. All children were subjected to history taking, clinical examination, routine investigations (CBC, CRP and ESR) and chest X-ray done for patients only, as well as determination of serum 25-OH vitamin D and plasma LL-37. Results: The study revealed a highly significant increase of WBCs, ESR and CRP and a highly significant decrease in hemoglobin of patients. Absence of history of sun exposure, increased WBCs counts and low levels of vitamin D and LL-37 were considered as risk factors for pneumonia while site of residence, hemoglobin level and platelets count were not. Both vitamin D and LL-37 were significantly lower in patients than controls (P < 0.001). There were significant positive correlations between vitamin D and LL-37 in studied groups. Conclusion: Appropriate concentrations of vitamin D facilitate the ability of immune system to defend against respiratory tract infections through enhancing LL-37 production. Keywords: vitamin D- LL 37- pneumoniaEgypt J Pediatr Allergy Immunol 2010;8(2):81-8
Human antimicrobial peptide LL-37 modulates proinflammatory responses induced by cytokine milieus and double-stranded RNA in human keratinocytes
No full textEpidermal keratinocytes produce proinflammatory cytokines/chemokines upon stimulation with cytokine milieus and Toll-like receptor ligands, which are considered to reflect epidermal environments in inflamed skin. The human antimicrobial peptide LL-37, besides having microbicidal functions, plays multiple roles as a "host defense peptide" in the immune system. Here, we examined the effect of LL-37 on proinflammatory responses induced by double-stranded RNA (dsRNA) and cytokines in primary human keratinocytes. LL-37 inhibited dsRNA-induced production of thymic stromal lymphopoietin (TSLP), CCL5/RANTES, CXCL10/IP-10, and CXCL8/1-8, which was attributable to interaction between LL-37 and dsRNA, although LL-37 upregulated CXCL8 expression at an earlier time point (8 h). LL-37 inhibited the increase of CXCL10 and CCL5 induced by TNF-alpha- and/or IFN-gamma but enhanced that of CXCL8. LL-37 and Th17 cytokines (IL-17 and IL-22) synergistically upregulated the expression of CXCL8 and IL-6. LL-37 showed the effects above at a high concentration (25 mu g/ml, 5.6 mu M). We also examined effects of a peptide with a scrambled LL-37 sequence, which has been frequently used as a negative control, and those of another peptide with the reversed LL-37 sequence, activities of which have not been well investigated. Interestingly, the reversed LL-37 had effects similar to LL-37 but the scrambled LL-37 did not. The modulation by LL-37 of the keratinocyte proinflammatory responses induced by cytokine milieus and dsRNA suggests novel roles for LL-37 in skin inflammation such as the promotion of IL17/IL-22/IL-6-associated psoriasis and suppression of TSLP-associated atopic dermatitis. (C) 2013 Elsevier Inc. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000318259100030&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Biochemistry & Molecular BiologyBiophysicsSCI(E)26ARTICLE4532-53743
Energy flux in isotropic turbulence under large variations of external forcing
No full textWe investigate the response of energy flux in isotropic turbulence to step-function like perturbation in external forcing at large length scales. From both physical experiments and direct numerical simulations, we measured the evolution of the Eulerian velocity structure functions, such as , , before and after the perturbation in forcing. In both cases, we observed the cascade of the energy excess at large scales cascade through scales to the dissipative range, which can be used to study the dynamics of the cascade, and in particular, to estimate the relevant time scales
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