20,288 research outputs found
Experimental study on heat transfer characteristics of metal foam/paraffin composite PCMs in large cavities: Effects of material types and heating configurations
No full textThis study explores the effects of material types and structural parameters of metal foam, and heating config-urations on the evolution of melting front, heat transfer characteristics, and temperature distribution of metal foam/paraffin composite phase change materials (PCMs) in large cavities. Copper and iron foams were used as the heat transfer enhancement medium, while paraffin with a melting point of 45 C was chosen as the PCM to store heat. This study identified the heat transfer regimes in large cavities during the melting process. The experimental results on different heating configurations indicated that different from small cavities, both con-duction and convection regimes played a fundamental role in the melting process. In addition, the heating configuration controlled the evolution of the melting front of the pure PCM and composite PCM. On the basis of these results, a non-dimensional correlation validated against a large dataset of experiments was fitted to model the melting process of the composite PCMs
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
Antimicrobial Mechanism of Antimicrobial Peptide LL-1 against Salmonella
No full textTo explore the antibacterial effect and mechanism of antimicrobial peptide LL-1 against Salmonella, the minimum inhibitory concentration (MIC) was determined by the doubling dilution method, and the antibacterial effect was evaluated by the growth inhibition curve. Then, the bacterial morphology was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of LL-1 on the cell wall and cell membrane of Salmonella was evaluated by detecting the leakage of intracellular nucleic acids, proteins and alkaline phosphatase (ALP) as well as by conducting propidium iodide (PI) staining experiments. The binding of LL-1 to Salmonella DNA was detected by nucleic acid gel electrophoresis. Finally, the effect of LL-1 on the energy metabolism of Salmonella was evaluated by measuring the activities of intracellular succinate dehydrogenase (SDH), NADP-malate dehydrogenase (NADP-MDH) and ATP levels. The results showed that the MIC was 6.25 μg/mL, and LL-1 had a good antibacterial effect in dose- and time-dependent manners. Salmonella treated with LL-1 showed morphological changes such as cell shrinkage, cell membrane dissolution, and plasmolysis. LL-1 resulted in the leakage of intracellular nucleic acids, proteins and ALP and an increase in the fluorescence intensity of PI-stained bacterial cells. Additionally, LL-1 could bind to bacterial DNA. Increasing LL-1 concentration resulted in a decrease in the intracellular ATP content, SDH and NADP-MDH activities. In conclusion, LL-1 could exert its antibacterial activity against Salmonella by increasing the permeability of the cell membrane and cell wall, thereby causing the leakage of intracellular contents, binding to DNA, and affecting bacterial energy metabolism. This study lays the foundation for further research on the antibacterial mechanism and application of LL-1
40Ar-39Ar Ages of L and LL Chondrites from Allan Hills, Antarctica: ALHA77015,77214 AND 77304
No full textP(論文)^(Ar)-^(Ar) ages have been determined for three chondrites (ALHA77015,77214,77304) from Allan Hills, Antarctica. Although younger ages have been observed at lower and higher temperatures for ALHA77015 (L3), the intermediate plateau-like age indicates a value of 4514±48 (1σ) Ma, though the plateau range is relatively narrow about 27% of the total ^(Ar). ALHA77304 (LL3) shows a typical plateau age of 4503±52 Ma at higher temperatures, covering about 46% of the total ^(Ar). Seriously weathered ALHA77214 (L or LL) exhibits a typical stair-case age pattern, increasing from about 1600 Ma up to about 4450 Ma. When coupled with reported data on other chondrites, there may be a rough correlation between the ^(Ar)-^(Ar) age and the degree of metamorphism defined from their petrologic type for unshocked L chondrites. However, such a trend is not clear for H and LL chondrites and a more systematic survey is required to settle the problem.departmental bulletin pape
GC-selective DNA-binding antibiotic, Mithramycin A, reveals multiple points of control in the regulation of Hdm2 protein synthesis
No full textThe primary role of the Hdm2/Mdm2 oncoprotein is to regulate the levels and activity of the transcription factor p53. Hdm2 synthesis is itself tightly controlled and, as demonstrated by a recently described SNP (SNP309) in the hdm2-P2 promoter, minor variations in Hdm2 expression have phenotypic consequences on radiation sensitivity and cancer predisposition. To further define mechanisms regulating Hdm2 expression, we have investigated the effects of the GC-selective DNA-binding drug, Mithramycin A (MA) on hdm2 mRNA transcription, trafficking, and translation. Firstly we show that the constitutive hdm2-P1 promoter is inhibited by MA. We define, for the first time, the minimal sequence elements that are required for P1-promoter activity and identify those which confer MA sensitivity. Secondly, MA induces p53-dependent transcription from the hdm2-P2 promoter. Thirdly, and critically, MA also inhibits Hdm2 synthesis at the post-transcriptional level, with negative effects on hdm2 mRNA nuclear export and translation. This study highlights the complex interplay between the pathways that regulate Hdm2 protein synthesis in cancer cells, and furthermore emphasizes the export of hdm2 mRNA from the nucleus to the cytoplasm as a key point of control in this process.<br/
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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Some rhetorical strategies in later nineteenth-century laboring-class poetry
No full textStructural and functional analysis of the pro-domain of human cathelicidin, LL-37
No full textCathelicidins form a family of small host defense peptides distinct from another class of cationic antimicrobial peptides, the defensins. They are expressed as large precursor molecules with a highly conserved pro-domain known as the cathelin-like domain (CLD). CLDs have high degrees of sequence homology to cathelin, a protein isolated from pig leukocytes and belonging to the cystatin family of cysteine protease inhibitors. In this report, we describe for the first time the X-ray crystal structure of the human CLD (hCLD) of the sole human cathelicidin, LL-37. The structure of hCLD, determined at 1.93 Å resolution, shows the cystatin-like fold and is highly similar to the structure of the CLD of the pig cathelicidin, protegrin-3. We assayed the in vitro antibacterial activities of hCLD, LL-37 and the precursor form, pro-cathelicidin (also known as hCAP18), and we found that the unprocessed protein inhibited the growth of Gramnegative bacteria with efficiencies comparable to the mature peptide, LL-37. In addition, the antibacterial activity of LL-37 was not inhibited by hCLD intermolecularly, since exogenously added hCLD had no effect on the bactericidal activity of the mature peptide. hCLD itself lacked antimicrobial function and did not inhibit the cysteine protease, cathepsin L. Our results contrast with previous reports of hCLD activity. A comparative structural analysis between hCLD and the cysteine protease inhibitor stefin A showed why hCLD is unable to function as an inhibitor of cysteine proteases. In this respect, the cystatin scaffold represents an ancestral structural platform from which proteins evolved divergently, with some losing inhibitory functions
Ak ll kentlerin afet yönetiminde dijital ikiz teknolojisi
No full textBu çal ma, ak ll kentlerin afet yönetiminde dijital ikiz teknolojisinin kullan m n incelemeyi amaçlamaktad r. Çal man n önemi, dijital ikiz teknolojisinin sundu u ileri seviye veri analizi ve simülasyon olanaklar n n, afetlere haz rl k, müdahale ve iyile tirme süreçlerindeki potansiyelini ortaya koymas ndan kaynaklanmaktad r. Bu sayede, afet yönetiminde daha etkili ve verimli çözümler geli tirilmesi hedeflenmektedir. Çal man n kapsam , ak ll kentler ve bu kentlerde dijital ikiz teknolojisinin nas l entegre edilebilece ini ele alarak, çe itli sektörlerdeki uygulamalar n ve do al afetlerle ba lant lar n de erlendirmekle s n rland r lm t r. Ayr ca, Türkiye'deki mevcut afet yönetim sistemleri ve dijital ikiz teknolojisinin bu sistemlere nas l entegre edilebilece i üzerinde de durulmaktad r. Çal man n amac , ak ll kentlerin afet yönetiminde dijital ikiz teknolojisinin potansiyel faydalar n bu alanda konuyu yeni yakla mlarla yorumlamaktad r. Bu çal mada ki amaç, dijital ikiz teknolojisinin afet yönetimindeki uygulanabilirli ini ve bu teknolojinin gelecekte nas l daha etkin bir ekilde kullan labilece ini belirlemektir. Böylece, ak ll kentlerde afet ve acil durumuna dikkat çekmektedir ve bu alan n daha da ileriye ta nmas amaçlanmaktad r. Bu kapsamda Türkiye'de ya anan 6-7 ubat depremleri öncesi ve sonras nda bu teknolojiden etkin yararlan lsayd nas l olurdu sorusuna k tutmaktad r
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