393 research outputs found
A Study on High Performance Fine-Grained Concrete Containing Rice Husk Ash
Rice husk ash (RHA) is classified as a highly reactive pozzolan. It has a very high silica content similar to that of silica fume (SF). Using less-expensive and locally available RHA as a mineral admixture in concrete brings ample benefits to the costs, the technical properties of concrete as well as to the environment. An experimental study of the effect of RHA blending on workability, strength and durability of high performance fine-grained concrete (HPFGC) is presented. The results show that the addition of RHA to HPFGC improved significantly compressive strength, splitting tensile strength and chloride penetration resistance. Interestingly, the ratio of compressive strength to splitting tensile strength of HPFGC was lower than that of ordinary concrete, especially for the concrete made with 20 % RHA. Compressive strength and splitting tensile strength of HPFGC containing RHA was similar and slightly higher, respectively, than for HPFGC containing SF. Chloride penetration resistance of HPFGC containing 10–15 % RHA was comparable with that of HPFGC containing 10 % SF
Surface waves control bacterial attachment and formation of biofilms in thin layers
Formation of bacterial biofilms on solid surfaces within a fluid starts when bacteria attach to the substrate. Understanding environmental factors affecting the attachment and the early stages of the biofilm development will help develop methods of controlling the biofilm growth. Here, we show that biofilm formation is strongly affected by the flows in thin layers of bacterial suspensions controlled by surface waves. Deterministic wave patterns promote the growth of patterned biofilms, while wave-driven turbulent motion discourages patterned attachment of bacteria. Strong biofilms form under the wave antinodes, while inactive bacteria and passive particles settle under nodal points. By controlling the wavelength, its amplitude, and horizontal mobility of the wave patterns, one can shape the biofilm and either enhance the growth or discourage the formation of the biofilm. The results suggest that the deterministic wave-driven transport channels, rather than hydrodynamic forces acting on microorganisms, determine the preferred location for the bacterial attachment
Characterisation of Bombyx mori odorant-binding proteins reveals that a general odorant-binding protein discriminates between sex pheromone components
In many insect species, odorant-binding proteins (OBPs) are thought to be responsible for the transport of pheromones and other semiochemicals across the sensillum lymph to the olfactory receptors (ORs) within the antennal sensilla. In the silkworm Bombyx mori, the OBPs are subdivided into three main subfamilies; pheromone-binding proteins (PBPs), general odorant-binding proteins (GOBPs) and antennal-binding proteins (ABPs). We used the MotifSearch algorithm to search for genes encoding putative OBPs in B. mori and found 13, many fewer than are found in the genomes of fruit flies and mosquitoes. The 13 genes include seven new ABP-like OBPs as well as the previously identified PBPs (three), GOBPs (two) and ABPx. Quantitative examination of transcript levels showed that BmorPBP1, BmorGOBP1, BmorGOBP2 and BmorABPx are expressed at very high levels in the antennae and so could be involved in olfaction. A new two-phase binding assay, along with other established assays, showed that BmorPBP1, BmorPBP2, BmorGOBP2 and BmorABPx all bind to the B. mori sex pheromone component (10E,12Z)-hexadecadien-1-ol (bombykol). BmorPBP1, BmorPBP2 and BmorABPx also bind the pheromone component (10E,12Z)-hexadecadienal (bombykal) equally well, whereas BmorGOBP2 can discriminate between bombykol and bombykal. X-ray structures show that when bombykol is bound to BmorGOBP2 it adopts a different conformation from that found when it binds to BmorPBP1. Binding to BmorGOBP2 involves hydrogen bonding to Arg110 rather than to Ser56 as found for BmorPBP1
The Novel Object and Unusual Name (NOUN) database: a collection of novel images for use in experimental research
Many experimental research designs require images of novel objects. Here we introduce the Novel Object and Unusual Name (NOUN) Database. This database contains 64 primary novel object images and additional novel exemplars for ten basic- and nine global-level object categories. The objects’ novelty was confirmed by both self-report and a lack of consensus on questions that required participants to name and identify the objects. We also found that object novelty correlated with qualifying naming responses pertaining to the objects’ colors. Results from a similarity sorting task (and subsequent multidimensional scaling analysis on the similarity ratings) demonstrated that the objects are complex and distinct entities that vary along several featural dimensions beyond simply shape and color. A final experiment confirmed that additional item exemplars comprise both sub- and superordinate categories. These images may be useful in a variety of settings, particularly for developmental psychology and other research in language, categorization, perception, visual memory and related domains
Deletion of parasite immune modulatory sequences combined with immune activating signals enhances vaccine mediated protection against filarial nematodes
<p>Background: Filarial nematodes are tissue-dwelling parasites that can be killed by Th2-driven immune effectors, but that have evolved to withstand immune attack and establish chronic infections by suppressing host immunity. As a consequence, the efficacy of a vaccine against filariasis may depend on its capacity to counter parasite-driven immunomodulation.</p>
<p>Methodology and Principal Findings: We immunised mice with DNA plasmids expressing functionally-inactivated forms of two immunomodulatory molecules expressed by the filarial parasite Litomosoides sigmodontis: the abundant larval transcript-1 (LsALT) and cysteine protease inhibitor-2 (LsCPI). The mutant proteins enhanced antibody and cytokine responses to live parasite challenge, and led to more leukocyte recruitment to the site of infection than their native forms. The immune response was further enhanced when the antigens were targeted to dendritic cells using a single chain Fv-αDEC205 antibody and co-administered with plasmids that enhance T helper 2 immunity (IL-4) and antigen-presenting cell recruitment (Flt3L, MIP-1α). Mice immunised simultaneously against the mutated forms of LsALT and LsCPI eliminated adult parasites faster and consistently reduced peripheral microfilaraemia. A multifactorial analysis of the immune response revealed that protection was strongly correlated with the production of parasite-specific IgG1 and with the numbers of leukocytes present at the site of infection.</p>
<p>Conclusions: We have developed a successful strategy for DNA vaccination against a nematode infection that specifically targets parasite-driven immunosuppression while simultaneously enhancing Th2 immune responses and parasite antigen presentation by dendritic cells.</p>
Hemodynamic and clinical onset in patients with hereditary pulmonary arterial hypertension and BMPR2 mutations
Background: Mutations in the bone morphogenetic protein receptor 2 (BMPR2) gene can lead to idiopathic pulmonary arterial hypertension (IPAH). This study prospectively screened for BMPR2 mutations in a large cohort of PAH-patients and compared clinical features between BMPR2 mutation carriers and non-carriers. Methods: Patients have been assessed by right heart catheterization and genetic testing. In all patients a detailed family history and pedigree analysis have been obtained. We compared age at diagnosis and hemodynamic parameters between carriers and non-carriers of BMPR2 mutations. In non-carriers with familial aggregation of PAH further genes/gene regions as the BMPR2 promoter region, the ACVRL1, Endoglin, and SMAD8 genes have been analysed. Results: Of the 231 index patients 22 revealed a confirmed familial aggregation of the disease (HPAH), 209 patients had sporadic IPAH. In 49 patients (86.3% of patients with familial aggregation and 14.3% of sporadic IPAH) mutations of the BMPR2 gene have been identified. Twelve BMPR2 mutations and 3 unclassified sequence variants have not yet been described before. Mutation carriers were significantly younger at diagnosis than non-carriers (38.53 ± 12.38 vs. 45.78 ± 11.32 years, p < 0.001) and had a more severe hemodynamic compromise. No gene defects have been detected in 3 patients with HPAH. Conclusion: This study identified in a large prospectively assessed cohort of PAH- patients new BMPR2 mutations, which have not been described before and confirmed previous findings that mutation carriers are younger at diagnosis with a more severe hemodynamic compromise. Thus, screening for BMPR2 mutations may be clinically useful
Successful surgical excision of primary right atrial angiosarcoma
Primary cardiac angiosarcoma is a rare and aggressive tumor with a high incidence of metastatic spread (up to 89%) at the time of diagnosis, which restricts the indication for surgical resection to a small number of patients. We report the case of a 50-year old Caucasian woman with non-metastatic primary right atrial angiosarcoma, who underwent successful surgical excision of the tumor (with curative intent) and reconstruction of the right atrium with a porcine pericardial patch. However, after a symptom-free survival of five months the patient presented with bone and liver metastases without evidence of local tumor recurrence
- …