142 research outputs found
Fysisch-mechanisch materiaalonderzoek waterbouwasfaltbeton.
No full textINHOUDSOPGAVE: Voorwoord 1. Inleiding 2. Beproevingstechnieken en monstergegevens 2.1. Mogelijkheden 2.2 Variabelen 2.3. Herkomst monsters 3. Beproevingsschema 3.1. Algemeen 3.2. Vervormingsges tuurde proeven naar bezwijken 3.3. Spanningsrelaxatle-proeven 3.4. Hoogfrequente vervormingsgestuurde proef 4. Resultaten 4.1. Vervormingsges tuurde proeven naar bezwijken 4.2. Spanningsrelaxatie-proeven 4.3. Hoogfrequente vervormingsgestuurde proef ConcluslesTAW A4 Asfalttoepassinge
Literatuurstudie naar het fysisch-mechanisch materiaalgedrag van asfaltbeton
No full textIn deze paragraaf worden de specifieke materiaaleigenschappen cq. kenmerken van asfaltbeton, zoals deze uit eerder onderzoek bekend zijn, weergegeven. - Het materiaal asfaltbeton heeft verschillende materiaalkarakteristieken voor trek- dan wel drukspanning. - De waarde van diverse materiaalparameters, zoals elasticiteitsmoduli en viscositeitscoëfficienten zijn sterk afhankelijk van de heersende temperatuur. - De steundruk is van duidelijk minder belang voor het materiaalgedrag dan bijvoorbeeld de temperatuur en de vervormingssnelheid. De invloed is echter wel groter naarmate de temperatuur van het asfalt toeneemt. - Voor trekspanningen lijkt het Burgers-model, eventueel aangevuld met plastische term(en) een redelijke benadering. Dit geldt echter alleen zolang er nog geen scheurvorming in het materiaal heeft plaatsgevonden. - De breukspanning van het materiaal is sterk afhankelijk van zowel de temperatuur als de vervormingssnelheid. De breukrek kan echter als onafhankelijk van de vervormingssnelheid worden beschouwd. Een scheurcriterium dient men dus altijd te relateren aan de opgetreden rek. - Met de name de methode van verwerken (verdichten) zorgt voor een anisotroop materiaalgedrag, dit komt het sterkst naar voren bij de stijfheid van het materiaal. - Bij het bepalen van de materiaalparameters dient men zeer gericht voor een bepaalde beproevingsmethode te kiezen, daar in het verleden is gebleken dat de verkregen waarden afhankelijk zijn van de gekozen methode. - Bij vervormingen onder drukspanning (kruipproeven DWW) wordt een niet-lineair materiaalgedrag aangetroffen. Het correcte materiaalgedrag onder drukspanning dient nader te worden onderzocht. - Het al dan niet volumebestendig zijn van het materiaal asfaltbeton is sterk afhankelijk van zowel het percentage aan holle ruimte dat in het mengsel aanwezig is als de grootte van de steundruk.TAW A4 Asfalttoepassinge
Role of fire in preventing bush encroachment in the Eastern Cape
No full textA serious bush encroachment problem has developed in the Eastern Cape and it has been suggested that this is partly the result of the elimination of regular, fierce veld fires. The author is of the opinion that it was rather the interaction of burning and wild browsing animals that played the major role in maintaining the original grasslands and preventing the encroachment of bush in the past. After a controlled burn had been applied to an area of dense, sweet grassveld, moderately encroached by Acacia karoo and other bush species, most of the bushes suffered a kill of stems and branches but coppiced from the base of the stem. Stocking lightly with goats controlled this coppice growth with no detrimental effect to the grass. These results indicate that a system of burning and browsing could be used in combating bush encroachment in certain situations.Keywords: sweetveld|goats|coppice growth|browsing|fires|bush encroachments|Eastern Cape Province|fire effects|browsers|grasslands|bushes|controlled burning
Tachinus (Tachinoderus) centralis Chang & Li & Yin & Schülke 2019, new species
No full text<i>Tachinus</i> (<i>Tachinoderus</i>) <i>centralis</i> Chang, Li, Yin & Schülke, new species <p>Chinese Common Name: 华中圆胸隐翅虫</p> <p>(Figs 3–4, 12)</p> <p> <b>Type material</b> (25 exs). <b>Holotype: CHINA:</b> Ƌ: ‘ China: Shaanxi, Ningshaan (宁陕县), Qinling, Ping-he-liangding (平河梁顶), N33.28.386, E108.29.612, alt. 2107 m, 1.v.2008, Huang Hao & Xu Wang leg.’ (SNUC). <b>Paratypes: CHINA:</b> 1 Ƌ, 2 ♀♀: ‘ China: Shaanxi Prov., Hanzhong city (汉中市), Nanzheng Country (南郑县), Yuanba Town, Liping (黎平) National F.P., 32°50’N, 106°36’E, alt. 1400–1600 m, 16.vii.2012, Chen, Li, Ma & Zhao leg.’ (SNUC); 1 ♂, 1 ♀: same label data, except ‘ Li Li-Zhen leg.’ (SNUC); 1 ♀: same label date, except ‘ 15.vii.2012 ’ (SNUC); 1 ♀: ‘ CHINA: (S-Shaanxi) Qinling Shan, river bank above Houzhenzi (厚畛子), 115 km WSW Xi’an, 1450 m, 33°50’N / 107°47’E (mixed deciduous forest, moss/leaves-sifted) 4.VII.2001 Wrase [06b]’ (cSch); 1 ♀: ‘ China: Shaanxi, Qin Ling Shan, 110.06 E, 34.27 N, Hua Shan Mt. N Valley, 1200-1400 m, 118 km E Xian, sifted, 18./ 20.08.1995, leg. A. Pütz’ (cPüt); 1 ♀: ‘ CHINA: Shaanxi Qinling Shan above Houzhenzi 115 km WSW Xi’an / 1450 m, 33°50’N 107°47’E 5.VII.2001 A. Smetana [C95b]’ (cSme); 1 ♀: ‘ CHINA: Shaanxi Qinling Shan pass rd. Zhouzhi Foping (周至佛坪) 105 km SW Xi’an / N-slope 1700 m 33°46’N 107°58’E 3.VII.2001 A. Smetana [C91]’ (cSme); 1 ♂, 1 ♀: ‘ CHINA: W-Hubei (Daba Shan) creek valley 8 km NW Muyuping (木鱼坪) 31°29’N, 110°22’E, 1550–1650 m, 18.VII.2001, leg. M. Schülke [CH01-16A] / creek valley, deciduous forest, moss (sifted) [CH 01-16A]’ (cSch); 2 ♂♂, 1 ♀: ‘ China: Chongqing city, Chengkou Coun (城口县), Gaonan xiang (高楠乡), West Da-ba-Shan (西大巴山), Guo Di Tang (锅底凼), N32.08.300, E108.37.022, alt. 1830 m, 24.iv.2008, Huang Hao & Xu Wang leg.’ (SNUC); 2 ♀♀: also from Gaonan xiang, except ‘ East Da-ba-Shan, upper Huang’an Gou (黄安沟), N31.51.785, E109.09.459, alt. 2039 m, 22–23.iv.2008, Huang Hao & Xu Wang leg.’ (SNUC); 1 ♂, 2 ♀♀: ‘ China: Sichuan Prov., Bazhong city (巴中市), Nanjiang Coun (南江县), Micang shan (米仓山), Daxiaolan Gou (大小兰沟), N32.40.021, E106.54.578, alt. 1350 m, 29.iv.2008, Huang Hao & Xu Wang leg.’ (SNUC); 2 ♂♂, 2 ♀♀: ‘ CHINA: SE Sichuan Jinfo Shan, 29°01’N 107°14’E, 1800 m, 27.VI.1998, A. Smetana [C72] / 1998 China Expedition J. Farkač, D. Král, J. Schneider & A. Smetana’ (1 ♂, 1 ♀ in cSme; 1 ♂, 1 ♀ in cSch).</p> <p> <b>Diagnostic description.</b> Male. Habitus as in Fig. 3A; TBL 3.34–4.05 mm, FBL 2.07–2.36 mm; head black, pronotal disc, elytra, abdomen and most parts of legs reddish-brown, antennomeres I–IV, mouthparts, and tarsi yellowish-brown. Head sub-triangular, HL 0.38–0.47 mm, HW 0.66–0.71 mm, with fine punctures; eyes prominent, EyL 0.14 mm; antenna elongate, AnL 1.46–1.65 mm, relative lengths of antennomeres I–XI: 1.25: 1: 1.25: 1.25: 1.25: 1: 1: 1: 1: 1: 1.5. Pronotum strongly transverse, PL 0.6 6– 0.75 mm, PW 1.27–1.32 mm, PI 0.52–0.57. Elytra slightly transverse, EL 0.81–0.99 mm, EW 1.18–1.27 mm, EI 0.76–0.78. Abdominal surface with microsculpture consisting of transverse waves; tergite VIII (Fig. 4A) with four relatively long lobes, inner lobes much longer than outer ones; sternite VII (Fig. 4B) shallowly and narrowly emarginate at middle along posterior margin, granules sparsely arranged in sub-rectangular area; sternite VIII (Fig. 4C) with four lobes, deeply and broadly incised between inner lobes, median length of sternite 0.75 times as long as depth. Length of aedeagus (Fig. 4 D–E) 0.60 mm, parameres short and broad, each slightly angulate at apex, strongly constricted at middle in lateral view.</p> <p>Female. General habitus (Fig. 3B) similar to male. Measurements: TBL 3.63–4.0 mm, FBL 2.26–2.40 mm, HL 0.38–0.47 mm, HW 0.66–0.71 mm, EyL 0.14 mm, AnL 1.55–1.70 mm, PL 0.71–0.75 mm, PW 1.32–1.41 mm, PI 0.53–0.54, EL 0.94–1.08 mm, EW 1.27–1.37 mm, EI 0.74–0.79. Tergite VIII (Fig. 4F) with four lobes, inner lobes slightly longer than outer ones, with additional pair of processes along inner margins; sternite VIII (Fig. 4G) with six lobes, fimbriate lobes longer than others.</p> <p> <b>Comparative notes.</b> <i>Tachinus centralis</i> is most similar to <i>T. striatulus</i> Ullrich, described based on a single female from northeastern Myanmar, in sharing an additional pair of processes along the inner margins of the inner lobes of female tergite VIII. Females of these two species can be tentatively separated by the incisions between the inner and outer lobes being distinctly deeper than that between the inner lobes, and the relatively much longer median and outer lobes of sternite VIII in the new species.</p> <p> <b>Distribution.</b> China: Shaanxi, Hubei, Chongqing, Sichuan (Fig. 12).</p> <p> <b>Etymology.</b> The specific epithet indicates the distribution of this species in central China.</p>Published as part of <i>Chang, Yuan, Li, Li-Zhen, Yin, Zi-Wei & Schülke, Michael, 2019, A review of the Tachinus longicornis - group of the subgenus Tachinoderus Motschulsky (Coleoptera: Staphylinidae: Tachyporinae) from China, pp. 478-494 in Zootaxa 4545 (4)</i> on page 482, DOI: 10.11646/zootaxa.4545.4.2, <a href="http://zenodo.org/record/2618275">http://zenodo.org/record/2618275</a>
FIGURE 7. Parapercis muronis. A. CSIRO H.6570-35, 115 in Three new species of Parapercis (Perciformes: Pinguipedidae) and first records of P. muronis (Tanaka, 1918) and P. rubromaculata Ho, Chang & Shao, 2012 from Australia
No full textFIGURE 7. Parapercis muronis. A. CSIRO H.6570-35, 115 mm SL, NW of Cape Leveque, WA, Australia (Photo: CSIRO); B. NMV A.29653-002, 81.6 mm SL, WSW of Barrow Island, WA, Australia (Photo: D. Bray); C. KAUM I.59514, 101 mm SL, Tosa Bay, Kochi, Japan. (Photo: KAUM) D. KAUM I.56085, 94.5 mm, off Iloilo, Panay Island, Philippines (Photo: KAUM).Published as part of Johnson, Jeffrey W. & Wilmer, Jessica Worthington, 2018, Three new species of Parapercis (Perciformes: Pinguipedidae) and first records of P. muronis (Tanaka, 1918) and P. rubromaculata Ho, Chang & Shao, 2012 from Australia, pp. 151-181 in Zootaxa 4388 (2) on page 177, DOI: 10.11646/zootaxa.4388.2.1, http://zenodo.org/record/118788
Synergistic anticancer effects of ganciclovir thymidine kinase and 5-fluorocytosine cytosine deaminase gene therapies
No full text[[alternative]]Small-molecule peptides inhibit Z alpha(1)-antitrypsin olymerization
No full text[[abstract]]The Z variant of α1-antitrypsin (AT) polymerizes within the liver and gives rise to liver cirrhosis and the associated plasma deficiency leads to emphysema. In this work, a combinatorial approach based on the inhibitory mechanism of α1-AT was developed to arrest its pathogenic polymerization. One peptide, Ac-TTAI-NH2, emerged as the most tight-binding ligand for Z α1-AT. Characterization of this tetrapeptide by gel electrophoresis and biosensor analysis revealed its markedly improved binding specificity and affinity compared with all previously reported peptide inhibitors. In addition, the peptide is not cytotoxic to lung cell lines. A model of the peptide-protein complex suggests that the peptide interacts with nearby residues by hydrogen bonds, hydrophobic interactions, and cavity-filling stabilization. The combinatorially selected peptide not only effectively blocks the polymerization but also promotes dissociation of the oligomerized α1-AT. These results are a significant step towards the potential treatment of Z α1-AT related diseases
[[alternative]]Characterization of novel α-ketoamide derivatives as potent inhibitors against cathepsin S induced by acidic extracellular pH in pancreatic cancer cells
No full text[[abstract]]Extracellular acidification is known to be a driving force in pancreatic cancer growth and metastasis. Thus, manipulation of acidic peritumoral pH or blockage of key proteins stimulated by acidic extracellular microenvironment may offer considerable potential for pancreatic cancer therapy. Cathepsin S, also known as CTSS or CatS, is a critical proteolytic enzyme found to be up-regulated in malignant cells and secreted into the extracellular milieu to degrade surrounding matrix components. By examining the effect of low pH (6.7) on various pancreatic tumor cell lines, we detected a consistently increased CTSS expression associated with augmented cell migration and invasion. Other features such as CTSS-mediated proteolysis and ECM degradation were also observed under mildly acidic condition. Based on these findings, we designed and synthesized some new small molecules bearing an α-ketoamide warhead to evaluate their ability to inhibit CTSS. Kinetic study revealed these compound inhibitors possess very low Ki values and high specificity against target CTSS enzyme. Further in vitro and in vivo analyses demonstrated these agents not only could protect fibronectin from CTSS-mediated degradation but also induce tumor cell autophagy under extracellular acidification. Together these results indicate the potential of α-ketoamide derivatives as antitumor agents against pancreatic cancer
Lysosomal cysteine proteinase cathepsin S as a potential target for anti-cancer therapy
No full text[[abstract]]In mammalian cells, cysteine proteinases are localized mainly in the cytoplasm and lysosomal compartments. For lysosomal cysteine proteinases, they are synthesized as inactive zymogens and converted to active forms occurred in the acidic and reducing conditions of late endosomes or lysosomes. Here we review the roles of active lysosomal cysteine proteinases in particular cathepsin S and its importance to many physiological or pathological processes including tumor growth, angiogenesis, and metastasis. Biochemical and clinical studies have shown significant changes in the levels of mRNA expression and enzyme activity of cathepsin S in various cancer tissues and cell lines. Immunologic, molecular and pharmaceutical approaches to alter the expression and proteolytic activity of cathepsin S all provided strong evidence for a causal role of this proteolytic enzyme in tumor progression and invasion. Determination of the X-ray structures of either cathepsin S alone or complexed with inhibitors further offered insights of the active site pocket of cathepsin S, thereby making the rational design of low-molecular weight synthetic inhibitors feasible for anti-cancer drug development and treatment
Tissue-specific cancer-related serpin gene cluster at human chromosome band 3q26
No full text[[abstract]]Approximately one quarter of the identified human serpin genes are cancer-related and clustered mainly at two distinct loci: 6p25 and 18q21. We have studied a novel serpin gene cluster at 3q26 containing at least two recently identified members: the pancreas-specific protease inhibitor, pancpin (PI14), and the brain-associated protease inhibitor, neuroserpin (PI12). In this, unlike a previous study, both PI14 and PI12 at 3q26 were found to consist of 9 exons and 8 introns and to share a perfectly conserved gene organization whose pattern is very different from that of the ov-serpin family. This distinct pattern appears identical in the genomic structures of human plasminogen activator inhibitor-1 (PA11) at 7q21 and protease nexin 1 (PI7) at 2q33-35, confirming that these four genes in three different chromosomes form a discrete subset within the serpin superfamily. As in the other three members whose gene expression is altered during tumorigenesis, PI12 expression was found to be down-regulated in tumor brain tissues and in two brain cancer cell lines: U-87 MG and H4, By screening genomic libraries, we isolated two overlapping clones showing that the marker SGC32223 (centromere) is located within intron F of PI12 and the marker WI-10077 (telomere) is located downstream of the 3'-flanking region of PI14. This finding indicates that the distance between human PI14 and PI12 is similar to 100 kb, and hence we speculate that other tissue-specific cancer-related serpin genes are likely to reside within this 3q26.1 cluster region. (C) 2000 Wiley-Liss, Inc
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