240 research outputs found
Design of a Computer Code To Evaluate the Influence of the Harmonics in the Electrical Networks
This paper aims to present the design of a computer code (HPFCODE), forcalculate a power flow and power losses in power systems under theinfluence of harmonics, using the GUI in MATLAB. After described theprogram was run for two networks IEEE 6 nodes and IEEE 14 nodes. Thepower flow by Newton-Raphson method was calculated as the losses ofactive and reactive power in the lines, respectively, where the loads arelinear and nonlinear (Static Var Compensator(SVC), Thyristor controlledReactor(TCR), and Unified Power Flow Controller ((UPFC)), The resultswere almost consistent and show the influence of higher harmonics onpower losses in electrical networks.DOI:http://dx.doi.org/10.11591/ijece.v2i5.146
Downy Mildew of Sunflowers in Tunisia and evaluation of four fungicides
Plasmopara halstedii, the downy mildew pathogen of sunflower (Helianthus annuus L.) causes significant economic losses world-wide, mostly through soilborne systemic infection of seedlings. Natural infection of sunflower with P. halstedii was monitored in sunflower fields cultivated in many regions of Beja, during a survey in the spring of 2010. P. halstedii were obtained from diseased sunflowers seeds in 2010 and characterized by virulence and by reaction to four fungicides: Ridomil MZ 58, Ridomil Gold 48%, Aliette 80% and Triziman 80%. These fungicides have significantly reduced the colony growth of the fungi compared to the control. The significant reduction of mycelia growth were obtained with Ridomil M, Triziman 80% and Aliette 80% with acompletely inhibition
Changes in the composition and fatty acid profile of Najdi ewes’ milk before and after weaning
This trial aimed to study the changes in the yield, composition, and fatty acid (FA) profile of ewes’ milk during suckling and milking periods. Nineteen multiparous Najdi ewes were kept under identical management and feeding conditions during a 12-week trial that was divided into two periods. Milk samples were collected on each sampling day from the total yield during the suckling (3rd, 6th, and 9th week) and milking (12th week) periods. The milk yield and the total solids, fat, protein, and lactose contents of the milk remained constant throughout the suckling weeks, but the protein content increased and milk yield and lactose content decreased after weaning. There were no differences in milk saturated FA (SFA), unsaturated FA (UFA), and monounsaturated FA (MUFA) contents during the suckling and milking periods, whereas the polyunsaturated FA content increased during the milking period. There were no differences in the individual milk SFA during the weeks of suckling, but the contents of caproic acid (C6:0), caprylic acid (C8:0), margaric acid (C17:0), and stearic acid (C18:0) decreased. However, myristic acid (C14:0), lauric acid (C12:0), and isomers of pentadecanoic (C15:0) acid increased during the milking period. The percentage of vaccenic acid (C18:1△11t), rumenic acid (C18:2△9c,11t; conjugated linoleic acid (CLA)), ω-3 FA group, and the atherogenicity index did not differ during the suckling period, but increased after weaning in the 12th week of lactation. This study demonstrated that weaning lambs in Najdi ewes is probably a factor that strongly affects milk traits by changing yield, composition, and FA profile.Keywords: CLA, dairy ewes, milk fat, milk yield, stage of lactatio
Clonal diversity of Acinetobacter baumannii from diabetic patients in Saudi Arabian hospitals
Carbapenem-resistant Acinetobacter baumannii (CR-AB) represents a major health-care problem causing high rates of morbidity and mortality. This study investigated the clonality of CR-AB isolated from diabetic patients from different regions in Saudi Arabia as well as the relatedness of the β lactamases genes. A total of 64 non-repetitive CR-AB clinical isolates were collected from 16 different regions in Saudi Arabia from intensive care patients. Isolates were identified phenotypically by Vitek 2 compact system and genotypically by amplification of blaOXA-51-like gene. The target sequences were amplified by PCR and the clonal diversity of the isolates was explored by PFGE. Resistance studies revealed that the prevalence of imipenem and meropenem resistance was 92% and 96%, respectively, while the vast majority of the isolates were susceptible to tigecycline and colistin. In addition, blaVIM and blaOXA-23 were the most prevalent genes in the isolates under investigation while ISAba1 was the most dominant insertion sequence. PFGE results showed 13 clusters; clone H was dominant comprising 20 isolates from four hospitals followed by clones C and F comprising 11 isolates each from 3 and 6 hospitals, respectively. Moreover, the current study signified the clonal diversity of CR-AB in Saudi Arabia and showed the ability of some clones to infect patients in many different cities
Composición bioquímica y potencial antioxidante del pepino del mar Mediterráneo comestible Holothuria tubulosa
The sea cucumber or holothurian is a marine species which has been prized in some Asian countries for its nutritional qualities. The purpose of this work was to study the biochemical composition and free radical scavenging and antioxidant activities of Holothuria tubulosa tegument from the Bizerta lagoon in northern Tunisia. The obtained data demonstrated that the extract of sea cucumber teguments exhibited high biochemical levels (such as moisture 80.77%, protein 7.07%, lipids 10.21%, energy value 13.64 Kcal/g ww), and an important nutritional value (including n-3/n-6: 2.11, EPA+DHA: 20.96, AI: 1.38 and TI: 0.54). High antioxidant activities were recorded in the integument by the radical scavenging tests of ABTS and DPPH as well as by the total antioxidant capacity and the FRAP in comparison with the BHT standard. Our results showed that H. Tubulosa tegument has high nutritional value with high antioxidant activities and could be considered a nutraceutical product.El pepino de mar o la holoturia es una especie marina apreciada en algunos países asiáticos por sus cualidades nutricionales. El propósito de este trabajo fue estudiar la composición bioquímica y las actividades antioxidantes y de eliminación de radicales libres del tegumento de Holothuria tubulosa de la laguna de Bizerta, en el norte de Túnez. Los datos obtenidos demuestran que el extracto de tegumentos de pepino de mar mostró altos niveles bioquímicos (como humedad 80,77%, proteína 7,07%, lípidos 10,21%, valor energético 13,64 Kcal/gww) y un valor nutricional importante (incluyendo n-3/ n-6: 2,11, EPA+DHA: 20,96, AI: 1,38 y TI: 0,54). Se registraron altas actividades antioxidantes en el tegumento mediante las pruebas de eliminación de radicales de ABTS y DPPH, así como por la capacidad antioxidante total y el FRAP, y esto, en comparación con el estándar BHT. Nuestros resultados mostraron que el tegumento de H. Tubulosa tiene un valor nutricional importante con una alta actividad antioxidante y podría considerarse un producto nutracéutico
Diversity of the Pythium community infecting crown and roots apple in Tunisia
The genus Pythium is important in agriculture, since it contains many plant pathogenic species. Little is known about the diversity of Pythium species causing apple dicline. Therefore, the aim of the study was to characterize 21 Pythium isolates collected from root and collar rot apple trees in Tunisia from 2006 through to 2009. The isolates were characterized morphologically as well as through sequence analyze of the internal transcribed spacer region (ITS). Three Pythium species were identified in this study P. rostratifingens, P. undulatum and P. sterilum. In virulence assays on excised apple twigsand in the fields, representative isolates of the different Pythium species isolated were pathogenic on the Anna, Lorka and Meski varieties and the MM106 rootstock. Results obtained show the great susceptibility of the MM106 rootstock to the infections for the different Pythium species tested
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What are the limitations on the wider therapeutic use of phage?
Bacterial resistance to antibiotics poses a serious health threat. Since research into new antibiotics is not progressing at the same rate as the development of bacterial resistance, widespread calls for alternatives to antibiotics have been made. Phage therapy is an ideal alternative candidate to be investigated. However the success of phage therapy may be hampered by a lack of investment support from large pharmaceutical companies, due to their narrow spectrum of activity in antibiotics, very large costs associated with clinical trials of the variety of phages needed, and regulatory requirements remaining unclear. Intellectual property is difficult to secure for therapeutic phage products for a variety of reasons, and patenting procedures vary widely between the US and the EU. Consequently, companies are more likely to invest in phage products for decontamination or veterinary use, rather than clinical use in humans. Some still raise questions as to the safety of phage therapy overall, suggesting the possibility of cytotoxicity and immunogenicity, depending on the phage preparation and route. On the other hand, with patients dying because of infections untreatable with conventional antibiotics, the question arises as to whether it is ethical not to pursue phage therapy more diligently. A paradigm shift about how phage therapy is perceived is required, as well as more rigorous proof of efficacy in the form of clinical trials of existing medicinal phage products. Phage therapy potential may be fulfilled in the meantime by allowing individual preparations to be used on a named-patient basis, with extensive monitoring and multidisciplinary team input. The National Health Service and academia have a role in carrying out clinical phage research, which would be beneficial to public health, but not necessarily financially rewarding
A step-by-step synthesis of triazole-benzimidazole-chalcone hybrids: Anticancer activity in human cells+
Novel series of triazole-benzimidazole-chalcone hybrid compounds have been synthesized via click chemistry, between different azide derivatives and substituted benzimidazole terminal alkynes bearing a chalcone moiety. The starting alkynes are prepared via base-catalysed nitrogen alkylation of pre-synthetized benzimidazole-chalcone substrates. All the intermediates as well as the final products are fully characterized by 1D and 2D NMR and mass spectrometry techniques. HMBC correlations permits the identification of a unique 1,4-disubstitued triazole-benzimidazole-chalcone isomer. Evaluation of the anti-proliferative potential in breast and prostate cancer cell lines showed that the presence of chloro substituents at the chalcone ring of the triazole-benzimidazole-chalcone skeleton enhanced the cytotoxic effects. The benzyl group linked to the 1,2,3-triazole moiety provides more antiproliferative potential.publishe
Investing in antibiotics to alleviate future catastrophic outcomes : what is the value of having an effective antibiotic to mitigate pandemic influenza?
Over 95% of post-mortem samples from the 1918 pandemic, which caused 50 to 100 million deaths, showed bacterial infection complications. The introduction of antibiotics in the 1940s has since reduced the risk of bacterial infections, but growing resistance to antibiotics could increase the toll from future influenza pandemics if secondary bacterial infections are as serious as in 1918, or even if they are less severe. We develop a valuation model of the option to withhold wide use of an antibiotic until significant outbreaks such as pandemic influenza or foodborne diseases are identified. Using real options theory, we derive conditions under which withholding wide use is beneficial, and calculate the option value for influenza pandemic scenarios that lead to secondary infections with a resistant Staphylococcus aureus strain. We find that the value of withholding an effective novel oral antibiotic can be positive and significant unless the pandemic is mild and causes few secondary infections with the resistant strain or if most patients can be treated intravenously. Although the option value is sensitive to parameter uncertainty, our results suggest that further analysis on a case-by-case basis could guide investment in novel agents as well as strategies on how to use them
Evaluating synergy between marbofloxacin and gentamicin in Pseudomonas aeruginosa strains isolated from dogs with otitis externa
The aim of this study was to determine antimicrobial susceptibility of Pseudomonas aeruginosa strains to marbofloxacin and gentamicin, and investigate the possible synergistic, additive, indifferent or antagonistic effects between the two agents. P. aeruginosa strains can develop resistance quickly against certain antibiotics if used alone, thus the need emerges to find synergistic combinations. A total of 68 P. aeruginosa strains isolated from dogs were examined. In order to describe interactions between marbofloxacin and gentamicin the checkerboard microdilution method was utilized. The MICs (minimum inhibitory concentrations) for marbofloxacin and gentamicin were in the range 0.25–64 mg/L and 0.25–32 mg/L, respectively. The combination of marbofloxacin and gentamicin was more effective with a MIC range of 0.031–8 mg/L and a MIC90 of 1 mg/L, compared to 16 mg/L for marbofloxacin alone and 8 mg/L for gentamicin alone. The FIC (fractional inhibitory concentration) indices ranged from 0.0945 (pronounced synergy) to 1.0625 (indifference). Synergy between marbofloxacin and gentamicin was found in 33 isolates. The mean FIC index is 0.546, which represents a partial synergistic/additive effect close to the full synergy threshold. In vitro results indicate that marbofloxacin and gentamicin as partially synergistic agents may prove clinically useful in combination therapy against P. aeruginosa infections. Although marbofloxacin is not used in the human practice, the interactions between fluoroquinolones and aminoglycosides may have importance outside the veterinary field
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