181 research outputs found
Antifouling strategy for marine transport efficiency in Nigeria: The isothiazolone option
Get PDFThe sustainability of Nigerian maritime industry is threatened by drag and deterioration caused by biofilms on painted marine structures. The bacterial population of scrapings from twenty boat hulls on Ojo waterside shores, Lagos, Nigeria and the antibacterial activity of in-can isothiazolone biocide against the isolated biofilm bacteria were investigated. The disc diffusion technique using Mueller Hinton agar (MHA) media and sterile filter paper discs immersed into the biocides was employed. Bacterial population density of the scrapings ranged from 1.3 to 2.2 x 10-5CFU/g. They were identified as Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus using the analytical profile index (API). All the isolates were susceptible to isothiazolone biocide with the highest inhibition zone of 24.75mm (P. mirabilis) and the lowest inhibition zone of 4.63mm (S. aureus). The MIC was observed as 15μl/ml (S. aureus), 5μl/ml (P. aeruginosa) and 5μl/ml (P. mirabilis) while MBC was 20μl/ml (S. aureus), 5 μl/ml (P. aeruginosa) and 15μl/ml (P. mirabilis). Results showed that isothiazolone biocide has broad spectrum antibacterial activity against bacterial biofilms on marine structures.Keywords: Biofouling; boat; isothiazolone biocides; maritime industry; Nigeri
Effect of fungi on dyes used in making Nigerian tie and dye cloths ('Adire') and shelf-life determination
Get PDFDye quality and fastness properties could only be guaranteed for a finite period of time on shelf. In this study, the shelf-life of natural indigo dye and indigo VAT dye was studied for 360 days. Physico-chemical parameters monitored includes; total viable count, viscosity, pH, specific gravity, absorbance and transmittance from 360 days. Fungi isolated from the dyes on shelf were Achaetomium strumarium, Aspergillus niger, Aspergillus flavus, Duitina rugosa, Penicillium citrinum and Peyronellaea prosopidis. The fungal population count was monitored monthly throughout the shelf-life study period. Multiple linear regression model was used to predict the shelf-life of the dyes from the growth data of the isolated organisms and the physico-chemical parameters. The total fungal viable counts ranged from 1.267×105 -3.213×105 spores ml-1 for indigo VAT dye and 1.453×105 - 3.347×105 spores ml-1 for natural indigo dye over the 12 months study period. The changes in the physico-chemical parameters ranged from pH 12.94±0.00-10.39±0.01 and 12.54±0.00-10.01±0.01, specific gravity 1.279±0.00-1.106±0.005 and 1.445±0.00-1.176±0.001, viscosity 1.288±0.00-1.215±0.001 cSt and 1.283±0.00- 1.176±0.001 cSt, optical density 1.627±0.002-3.323±0.001 and 1.705±0.001- 3.315±0.002, transmittance 5.573±0.003-2.652±0.001 and 6.124±0.002-2.108±0.001 for indigo VAT dye and natural indigo dye respectively. The percentage dye exhaustion of the shelf-life products determined after the study period peaked at 88±0.001 and 90±0.001 % for indigo VAT dye and natural indigo dye respectively. The shelf-life were found to be 17 months and 10 months for indigo VAT dye and natural indigo dye respectively. The synthetic indigo VAT dye has a higher shelf-life than the natural indigo dye. Imported indigo VAT dye is however recommended based on its longer shelf-life. The results further buttressed the trend where textile dyers in Nigeria and indeed the West African region largely employ imported indigo VAT dye than locally produced natural indigo dye.Keywords: Shelf-life; Nigerian tie and dye cloths 'Adire'; indigo VAT dye; natural indig
The Antibacterial Activity of ZrO2 Nanoparticles on Biocide Resistant Bacilli in Paints.
No full textThe antibacterial activity of four biocides against members of the class Bacilli isolated from paint and paint scrapings was investigated using the disc diffusion technique. Bacillus species were selected for this study amongst other organisms isolated from paint and paint scrapings because they were regularly isolated in highest populations when compared with other isolates detected. The biocides were made up of benzimidazole carbamate/2-n-octyl-4-isothiazolin -3-one (OIT)/Urea derivative), (5-Chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (CIT/MCIT); (Carbendazim octylisothiazolone and Diuron) and (Chloromethyl and methylisothiazolone). Bacillus cereus and B. coagulans had 0% inhibition of all the biocides tested. Similar experiments with ZrO2 nanoparticles yielded 65% inhibition of Bacillus sphaericus and 80% of Brevibacillus choshinensis. The result of this study indicates the need for more sophisticated antimicrobials and underscores the superior efficacy of nano-structured antimicrobials over conventional biocides used in the paint industry. These findings will enhance efforts geared towards combating biocide-resistant microorganisms in the paint industry
Hierarchy in Meritocracy: Community Building and Code Production in The Apache Software Foundation
No full textThis research is about code production in top-level open source communities of The Apache Software Foundation (ASF). We extensively analyzed Subversion repository logs from 70 top-level Apache open source projects in the ASF from 2004 to 2009. Based on interactions in code production during one-year periods we constructed networks of file co-authorship that gave us access to the organization of Apache open source communities. This allowed us to measure graph level properties, like hier- archy and clustering, and their influence on the outputs of code production. Apache communities are groups of individuals that organize their code production efforts in order to develop enterprise-grade open source software. The ASF explains the success of its communities and the software they produce by claiming to have instituted a meritocracy that brings contributors together in a way that significantly influences code production, namely by building communities instead of only focusing on technical properties of the source code like modularity. Self-organization theory has found that the role of institutions is minor. In this research we test and confirm the theory of self-organization, and find that the meritocracy institution does not influence code production.Management of TechnologyPolicy, Organization, Law and GamingTechnology, Policy and Managemen
Preferential crystallization of a racemic compound via its conglomerate co-crystals
No full textPreferential crystallization, as a powerful chiral resolution technique, is intrinsically limited to chiral molecules that crystallize as conglomerates. Many studies have been conducted on using chemical reactions to convert the target molecules, which originally form racemic compounds, into conglomerate-forming derivatives salts or by creating solvate, for the application of preferential crystallization. Up to this date conglomerate co-crystals of racemic compounds have never been applied as the intermediate for chiral resolution. In this study, preferential crystallization of the model compound Ibuprofen (IBU), originally a racemic compound, was carried out via its conglomerate co-crystal with 2,4-bipyridine ethylene (BPE) in heptane. Suitable operation conditions were selected based on pseudobinary phase diagram of the model compound system constructed under different IBU-BPE ratio. A unique measurement method combining polarimeter and Nuclear Magnetic Resonance (NMR) measurements was developed to identify the enantiopurity and the yield of the final product, which was a mixture of racemic IBU and IBU-BPE co-crystals, a likely result from this complex system. With respect to the results, preferential crystallization of IBU was successfully performed by slowly cooling down a saturated solution of racemic IBU-BPE, initially at T=57.5°C, after seeding it with S-IBU/BPE crystals to T=53°C with a cooling rate of 0.3°C/min. The recovered crystalline product contained pure IBU and a mixture of R-co-crystals and S-co-crystals with a yield of 44%, with the amount of S-co-crystals recovered four times higher than the amount of R-co-crystals present in the final product. The existence of R-IBU/BPE indicates that the primary nucleation of the undesired enantiomer still took place. This can be minimized by performing the experiment at bigger scale, where samples of the mother liquor can be taken during the process in order to monitor the evolution of the enantiomeric excess enabling the defining of an optimum filtration time. The crystallization of racemic IBU along with the cocrystals lowered the purity of S-IBU. By using new ratios of IBU/BPE close to the stoichiometric co-crystal ratio and with IBU in excess, this impurity can be diminished. Additionally a comprehensive study of the Metastable Zone Width (MSZW) in a bigger volume and the exploration of mixture of solvents can improve the definition of the final temperature in order to avoid the presence of racemic IBU and R-co-crystals in the crystals produced.Mechanical, Maritime and Materials EngineeringProcess and Energ
Leptoplana tremellaris O.F. Muller 1774
No full textLeptoplana tremellaris (O.F. Muller, 1774) (Figures 4–5) Distribution in Tunisia: 15 specimens were collected from under rocks in the lagoon of Tunis (36 ° 49 ' 06.61" N; 10 ° 17 ' 23.37" E). Other localities: United Kingdom: Fleming (1823), Gamble (1893), Faubel (1983), Faubel & Warwick (2005). France: Keferstein (1868). Belgium: Beneden (1860). Egypt: Palombi A (1928). Italy: Steinböck (1933). Croatia: Steinböck (1933). c v d: common vas deferens, f p: female pore, o v: oviduct, p h: pharynx, v: vagina, v d: vasa deferentia. c: circular muscle, c v d: common vas deferens, d: diagonal muscle, f p: female pore, l: longitudinal muscle, mp: male pore, o v: oviduct, p v: prostatic vesicle, s g: shell glands, s v: seminal vesicle, v: vagina. Material examined: 5 mature specimens were sectioned sagittally. The material examined was deposited in the Museo Nacional de Ciencias Naturales de Madrid (Spain). Description: Externally very similar to Echinoplana celerrima. Length up to about 30 mm, body shape broadly oval. Dorsal surface yellowish-brown with a dark band in the median line (Fig. 4 A). Tentacles lacking. With about 36 cerebral eyes arranged in two clusters, and about 60 lateral tentacular eyes. The cerebral eyes are smaller and more anterior than the tentacular eyes (Fig. 4 B). The ruffled pharynx is situated in the anterior half of body (Fig. 4 C). It opens onto the outside by a mouth located in the posterior third of the pharyngeal cavity. The two genital pores are well separated and situated in the last third of the body. Between them and closer to the male pore, a fold of the ventral wall, lined by a thickening of the body musculature is present. It corresponds to the so-called “sucker” present in some species of the genus Leptoplana (Figs. 4 F; 5 A). Male copulatory apparatus: The male copulatory apparatus is directed backwards. The coiled vasa deferentia appear on either side of the posterior end of the pharynx, continue anteriorly near the posterior quarter of the pharynx, then diverge laterally and run posteriorly to converge into the proximal end of the seminal vesicle. The anterior, frontally oriented branches of vasa deferentia may anastomose with the caudally oriented ducts (Fig. 4 C). The muscular seminal vesicle is located dorsally and very close to the pharynx. The prostatic organ is interpolated and tubular in shape (Fig. 5 c). It is subdivided into three compartments characterized by different epithelium lining. The whole size of the prostatic vesicle is relative to the volume of seminal vesicle. From the distal end of the prostatic vesicle, a narrow canal oriented obliquely and anteriorly acts as an eversible unarmed cirrus, provided distally with a penis papilla. This opens into a relatively large penial cavity. The male copulatory complex is enclosed within a thick muscular bulb, which can be seen by transparency in gently squashed living animals. Female copulatory apparatus: The female genital pore leads into a shallow antrum feminum or vagina externa, which extends dorsally to open into the widened vagina media. The vagina media runs dorsally and turns posteriorly to form the vagina interna, which receives the common oviduct (Figs. 4 E; 5 B). Large amounts of eosinophilous mucous secretion of glandular origin were observed inside the vagina. In two specimens fixed just after copulation, the vagina was expanded and filled with a mass of sperm (Fig. 5 B). Remarks. Leptoplana tremellaris, the type species of the genus Leptoplana, has a worldwide distribution, and was extensively re-described by Bock (1913) and Faubel (1983). The latter author placed the species within the family Leptoplanidae Stimpson, 1857. Prudhoe (1985) accepted the taxonomic position within the Leptoplanidae, in the subfamily Leptoplaninae Marcus, 1947. L. tremellaris is usually confused with E. celerrima and also with species of the genus Notoplana to which it is similar in shape and color. Living specimens of E. celerrima and L. tremellaris can nonetheless be easily distinguished, as in the ventral face of E. celerrima the cirrus and the “H” shaped vasa deferentia can be seen by transparency (Fig. 1 C). On the contrary, in L. tremellaris the cirrus is missing and the vasa deferentia are “M” shaped (Fig. 4 C). The majority of sectioned specimens of L. tremellaris showed an invagination between the male and female pore, known as “sucker” (Figs. 4 F; 5 A), distinct from the true sucker of the Cotylea, located behind the female pore and clearly evaginated. One specimen was seen to be without this structure. This specimen showed nonetheless a well developed seminal vesicle and was fully sexually mature (Fig. 5 C). It has to be noted that some species of the genus Leptoplana were described as being without a sucker (Boone, 1929; Hyman, 1953). Based on observations above, we suppose that the presence of a sucker between genital pores in Leptoplanidae, being subject to intrapopulational variation, possibly linked to maturity/ copulation stages, could not be used for systematic purposes.Published as part of Gammoudi, Mehrez, Tekaya, Saïda & Noreña, Carolina, 2009, Contribution to the knowledge of Acotylean Polyclads (Platyhelminthes, Polycladida) from Tunisian Coasts, pp. 43-60 in Zootaxa 2195 on pages 49-52, DOI: 10.5281/zenodo.27510
Innovative solution – key factor for sustainable development of modern business
No full textThe article examines the approaches of modern scientists to the definitions of "decision" and "administrative decision". The author offered a definition of "innovative solution", and the principles of innovation decision-making and the role of the adoption of innovative solutions in the economic activities of modern enterprises
Ein überflüssiger Gelehrtenstreit aus den Jahren 1983–1991
No full textIn the artcile the author deals with a controversis between the Turkologist, Mongolist, Tungusologist and Altaicist G. Doerfer and the Turkologist O.F. Sertkaya from the years 1983–1991. The whole matter was starting with a paper written by Doerfer to demonstrate the principles of writing reviews which led to the unnecessary dispute between the two scholars based on deeeply misunderstandings
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