Soil-structure Interaction Under Dynamic Loads

A theoretical study of the soil-structure interaction effects on the dynamic behaviour of structures is presented. The substructure approach is employed for which foundation impedance functions are derived from static and dynamic continuum theories. Both rigid and flexible structures supported by various types of foundations are investigated. The free vibration analysis of the soil-structure interaction system indicates that the damped natural frequencies of structures on flexible foundation may be lower or higher than the undamped natural frequencies. It also shows that the foundation flexibility provides damping to the structure due to energy dissipation in soil and modifies the original structural damping. The effect of the foundation on the damping of structures is calculated using an energy consideration and by means of the complex eigenvalue analysis. Both methods give almost the same results for the first mode but may give considerably different results for the higher vibration modes.;The dynamic response of the soil-structure interaction system excited by shock, earthquake and wind loading is investigated. The analysis of hammer foundations, the most typical of the shock experiencing structures, proves that the complex eigenvalue method is an efficient and accurate method of response prediction. Using this approach, the response of hammer foundations to either initial velocity of the anvil or pulse loading can be treated for any number of degrees of freedom.;Seismic loading and response of buildings depend on the flexibility of the foundation and its type. Shallow flexible foundations may increase the response and decrease the seismic forces of the structure, as compared to the response of the same structure on a rigid base. For pile foundations, the number and type of piles, their arrangement and the pile connection with the cap come into play. The study shows that, for small buildings and/or low intensity of earthquakes, the rigid connection of piles with the cap may not be necessary. The response of rigid structures to seismic loading is dealt with efficiently using the direct random vibration analysis.;Finally, the effect of foundation flexibility on structural response to gusting wind is explored using the gust factor approach. The parametric study indicates that while the gust effect factor may or may not be sensitive to soil flexibility, the resultant vibration may be substantially modified

Characterization of the glycocalyx of the human chondrocyte cell lines C-28/I2 and T/C-28a2 using lectins

Für ein besseres Verständnis des Knorpelaufbaus und des Entstehens von degenerativen Gelenkserkrankungen wie beispielsweise Osteoarthritis könnten in-vitro Studien an Chondrozyten-Zellkulturen einen wichtigen Beitrag leisten. Menschliche Primärzellen eines einzelnen Spenders sind aber in entsprechender Menge für groß angelegte Studienreihen nur schwierig zu erhalten und Zellkulturen unterschiedlicher Spender können in Abhängigkeit des Gesundheitszustandes und Alters der Spender sehr unterschiedliche Eigenschaften aufweisen. Darüber hinaus besitzen primäre Zellen meist nur eine stark begrenzte Lebensdauer. Allerdings reagieren sie sehr viel ursprünglicher als immortalisierte Zelllinien und entsprechen daher eher den Verhältnissen im Organismus. Da primäre Zellen aber eine in-vivo-ähnliche Umgebung benötigen, ist ihre Kultivierung sehr komplex und erfordert zahlreiche Adaptionen, wie z.B. die der Medienzusammensetzung oder der entsprechenden Kultivierungsoberfläche. Aus all diesen Gründen sollten in der vorliegenden Arbeit immortalisierte Zelllinien eingesetzt werden. Diese Zelllinien haben den Vorteil, dass auf Grund der besseren Verfügbarkeit und Vergleichbarkeit die Durchführung standardisierter und reproduzierbarer Experimente wesentlich einfacher ist. Da aber über deren Charakteristika noch immer relativ wenig bekannt ist, lag das Ziel der vorliegenden Diplomarbeit darin, die Glycocalyx der immortalisierten humanen Chondrozyten-Zelllinien C-28/I2 und T/C-28a2 näher zu untersuchen. Dazu wurden Monolayer dieser Zellkulturen mit fluoreszenzmarkierten Lektinen definierter Bindungsaffinität für verschiedene Zuckerstrukturen inkubiert. Anschließend sollten anhand des gebundenen Anteils der Lektine spektrofluorimetrisch Rückschlüsse auf die Saccharid-Strukturen in der pericellulären Matrix gezogen werden.To date, little is known about the composition of carbohydrate residues present in the extracellular matrix (ECM) of cultured human chondrocytes. However, this information might be of relevance for studies on cartilage tissue engineering or drug targeting. Therefore, the present study was performed to evaluate the binding patterns and specificities of selected lectins with affinity for distinct carbohydrate structures on C-28/I2 and T/C-28a2 chondrocyte monolayer cultures. Moreover, experiments involving enzymatic pre-treatment of the chondrocyte monolayers aimed at a further characterization of the cultured chondrocyte extracellular matrix. The bioadhesive properties of a panel of fluorescein-labelled lectins with specificities for different carbohydrate structures were investigated by spectrofluorometry. To ascertain the specificity of the lectin-cell interaction competitive inhibition assays using complementary carbohydrates were performed. As compared to that of other lectins, highest binding capacity in both cell lines was yielded with wheat germ agglutinin (WGA), which indicates a notable presence of N-acetyl-D-glucosamine structures as contained in hyaluronan chains. To further specify the binding characteristics of the lectins to the chondrocyte ECM confluent T/C-28a2 cells were pretreated with neuraminidase for digestion of sialic acids prior to incubation with a constant amount of WGA, PNA and STL. After sialic acid digestion only the binding capacity of PNA significantly increased and remained constant upon elevation of neuraminidase concentration. This explicit increase in binding capacity of PNA indicates the successful enzymatic removal of sialic groups, since it is known that PNA is only specific for terminal 2-acetamido-2-deoxy-3-O-ß-D-galactopyranosyl-D-galactose residues which are known to be present in keratan sulfate and masked with sialic acid groups. As compared to PNA, the WGA binding capacity of the chondrocyte ECM only slightly increased. These findings suggest that N-acetylneuraminic acid, the predominant sialic acid, is involved only in low-affinity interactions of WGA. Using N-acetyl-D-glucosamine (GlcNAc) as corresponding carbohydrate in competitive assays high inhibition values were observed for both cell lines, indicating a high specificity of WGA for GlcNAc. The results of another assay using chitotriose as competitive inhibitor indicates that WGA seems to bind to internal GlcNAc residues in large oligosaccharides with high affinity. Due to this reason hyaluronidase-digested hyaluronic acid consisting mainly of hyaluronan tetrasaccharides was prepared and used for competitive inhibition. IC50 values observed with these oligosaccharides were several times lower in case of both cell lines as compared to the monosaccharide GlcNAc. We therefore hypothesize that hyaluronan might represent a target structure for WGA in the glycocalyx of cultured chondrocytes. In conclusion, this study could be used as a basis for a more detailed evaluation of the properties of the chondrocyte glycocalyx

Glucosinolates, Glycosidically Bound Volatiles and Antimicrobial Activity of Brassica oleraceae Var. Botrytis, (Soultany Cultivar)

Background: Egyptian cauliflower Brassica oleracea, L. var. Botrytis L. Soultany cultivar, is an important edible plant in Mediterranean countries. Only a few researches were focused on antimicrobial activity of its volatiles and glucosinolates. Objective: To evaluate the antimicrobial activity of volatiles and glucosinolates of Egyptian Cauliflower and identify them by GC/MS and HPLC/MS designs. Materials and Methods: The semi-volatile and volatile constituents of were extracted by hydrodistillation from leaves, stems and inflorescences, using a Likens –Nickerson-type apparatus. The extracts from fresh and frozen vegetables were investigated by GC/MS and HPLC/MS. the volatile samples containing glucosinolate degradation products were evaluated for antimicrobial activity using the disc diffusion method. Results: From the fresh leaves extract, a total of 49 compounds were identified, representing 98.79% of the oil. The major constituent was found to be hex-3(Z)-enol (18.86%). From fresh disrupted inflorescence tissues of Egyptian cauliflower 45 compounds were detected, representing 93.37% of the extract. Nonacosane and 11-methoxy   benz(a)anthracene-7,12-dione   were   identified  as  major constituents   of   the hydrodistillation products, representing, respectively, 17.7 and 8.31% of the volatiles.   From frozen inflorescence tissues, dimethyl trisulfide and butylated hydroxy toluene were detected as predominant components representing 15.88 and 9.69% respectively. In the latter, hex-3(Z)-enol was not found to be the major constituent as happened in fresh leaves, but representing 3.88%. From fresh stem tissues, dimethyl trisulphide was detected as major constituent representing a percentage (24.06%) more than present in frozen inflorescence tissues. Twenty two compounds were identified by triple quad HPLC/MS. Volatile samples expressed a wide range of growth inhibition activity against both Gram-positive and Gram-negative bacteria and fungi, showing the highest inhibitory effects against E .coli and K. pneumonia strains. Conclusion: Hydrodistilled compounds present in the stems, leaves and inflorescence tissues of this cultivar has a highly promising antimicrobial activity. Keywords: Cauliflower, Brassica oleraceae, Glucosinolates, GC/MS, HPLC/MS, Antimicrobial activity.

¹H-NMR metabolic profiling, antioxidant activity, and docking study of common medicinal plant-derived honey

The purpose of this investigation was to determine ¹H-NMR profiling and antioxidant activity of the most common types of honey, namely, citrus honey (HC1) (Morcott tangerine L. and Jaffa orange L.), marjoram honey (HM1) (Origanum majorana L.), and clover honey (HT1) (Trifolium alexandrinum L.), compared to their secondary metabolites (HC2, HM2, HT2, respectively). By using a ¹H-NMR-based metabolomic technique, PCA, and PLS-DA multivariate analysis, we found that HC2, HM2, HC1, and HM1 were clustered together. However, HT1 and HT2 were quite far from these and each other. This indicated that HC1, HM1, HC2, and HM2 have similar chemical compositions, while HT1 and HT2 were unique in their chemical profiles. Antioxidation potentials were determined colorimetrically for scavenging activities against DPPH, ABTS, ORAC, 5-LOX, and metal chelating activity in all honey extract samples and their secondary metabolites. Our results revealed that HC2 and HM2 possessed more antioxidant activities than HT2 in vitro. HC2 demonstrated the highest antioxidant effect in all assays, followed by HM2 (DPPH assay: IC50 2.91, 10.7 μg/mL; ABTS assay: 431.2, 210.24 at 50 ug/mL Trolox equivalent; ORAC assay: 259.5, 234.8 at 50 ug/mL Trolox equivalent; 5-LOX screening assay/IC50: 2.293, 6.136 ug/mL; and metal chelating activity at 50 ug/mL: 73.34526%, 63.75881% inhibition). We suggest that the presence of some secondary metabolites in HC and HM, such as hesperetin, linalool, and caffeic acid, increased the antioxidant activity in citrus and marjoram compared to clover honey

Induction of antibacterial metabolites by co-cultivation of two Red-Sea-sponge-associated actinomycetes <i>Micromonospora</i> sp. UR56 and <i>Actinokinespora</i> sp. EG49

Liquid chromatography coupled with high resolution mass spectrometry (LC-HRESMS)-assisted metabolomic profiling of two sponge-associated actinomycetes, Micromonospora sp. UR56 and Actinokineospora sp. EG49, revealed that the co-culture of these two actinomycetes induced the accumulation of metabolites that were not traced in their axenic cultures. Dereplication suggested that phenazine-derived compounds were the main induced metabolites. Hence, following large-scale co-fermentation, the major induced metabolites were isolated and structurally characterized as the already known dimethyl phenazine-1,6-dicarboxylate (1), phenazine-1,6-dicarboxylic acid mono methyl ester (phencomycin; 2), phenazine-1-carboxylic acid (tubermycin; 3), N-(2-hydroxyphenyl)-acetamide (9), and p-anisamide (10). Subsequently, the antibacterial, antibiofilm, and cytotoxic properties of these metabolites (1&ndash;3, 9, and 10) were determined in vitro. All the tested compounds except 9 showed high to moderate antibacterial and antibiofilm activities, whereas their cytotoxic effects were modest. Testing against Staphylococcus DNA gyrase-B and pyruvate kinase as possible molecular targets together with binding mode studies showed that compounds 1&ndash;3 could exert their bacterial inhibitory activities through the inhibition of both enzymes. Moreover, their structural differences, particularly the substitution at C-1 and C-6, played a crucial role in the determination of their inhibitory spectra and potency. In conclusion, the present study highlighted that microbial co-cultivation is an efficient tool for the discovery of new antimicrobial candidates and indicated phenazines as potential lead compounds for further development as antibiotic scaffold

The genus <i>Micromonospora</i> as a model microorganism for bioactive natural product discovery

This review covers the development of the genus Micromonospora as a model for natural product research and the timeline of discovery progress from the classical bioassay-guided approaches through the application of genome mining and genetic engineering techniques that target specific products. It focuses on the reported chemical structures along with their biological activities and the synthetic and biosynthetic studies they have inspired. This survey summarizes the extraordinary biosynthetic diversity that can emerge from a widely distributed actinomycete genus and supports future efforts to explore under-explored species in the search for novel natural products

Management of hepatitis C virus genotype 4: recommendations of an international expert panel.

HCV has been classified into no fewer than six major genotypes and a series of subtypes. Each HCV genotype is unique with respect to its nucleotide sequence, geographic distribution, and response to therapy. Genotypes 1, 2, and 3 are common throughout North America and Europe. HCV genotype 4 (HCV-4) is common in the Middle East and in Africa, where it is responsible for more than 80% of HCV infections. It has recently spread to several European countries. HCV-4 is considered a major cause of chronic hepatitis, cirrhosis, hepatocellular carcinoma, and liver transplantation in these regions. Although HCV-4 is the cause of approximately 20% of the 170 million cases of chronic hepatitis C in the world, it has not been the subject of widespread research. Therefore, this document, drafted by a panel of international experts, aimed to review current knowledge on the epidemiology, natural history, clinical, histological features, and treatment of HCV-4 infections

Conception de station d'épuration

A l’échelle mondiale, le traitement des eaux usées constitue le premier enjeu de santé publique.Au Liban le problème d’eau usée est devenue très répandue et très graves c’est pourquoi le ministère d’eau a lancé une série des projets qui servent à traiter l’eau résidentielle et industrielle dans plusieurs régions au Liban.La plupart des stations existant comme celle à Beyrouth (Ghadire) font seulement le traitement préliminaire et celle au Saida et après le traitement l’eau est déchargée dans la mer à distance de 2 Km de la côte. Ceci à cause de manque d’expérience et des connaissances chez les entrepreneurs libanais dans le domaine de conception et de réalisation des stations d’épuration complète par conséquence le traitement n’a pu dépassé la première phase.Au sein de mon entreprise, un projet de conception et de réalisation de station d’épuration d’eaux usées dont la finalité est la protection du milieu naturel est en voie de réalisation.Selon la nature ou l’importance de la pollution, différents procédés peuvent être mises en oeuvre pour l’épuration des rejets résidentiels et industriels en fonction des caractéristiques spécifiques de ces derniers et de degré d’épuration désiré. Il faut noter d’ailleurs que pour un même type de pollution, on peut envisager des solutions d’épuration diverses. Le choix de celles à retenir doit faire intervenir non seulement des considérations d’ordre technique, liéespar exemple à l’efficacité relative des divers procédés possibles, mais aussi au point de vue économique portant sur l’estimation des frais d’investissement de fonctionnement et d’exploitation.Enfin la solution choisie doit être suffisamment souple pour permettre des aménagements ultérieurs qui tiendront compte de l’évolution rapide de technique de dépollution et d’une réglementation plus sévère