2,104 research outputs found
A Study on Mass Spectrometry of Methylated [60] Fullerenes Using the âIn-beamâ Electron Impact Technique
Mass spectra of the methylated [60]fullerenes were obtained by EI mass spectrometry using âdesorptionâ or âin-beamâ technique. The mass spectra of the methylated fullerenes, C60Men, have the molecular ion peak M+ indicating that the product is stable under the MS (EI) conditions. The appearance of an intense peak at m/z 360 was assigned to the formation of fullerene dication C60++. The remaining peaks were assigned to successive loss of methyl groups from molecular monocation and dication
The Shakespearean Poetic Rosary: The âSacred Numbersâ in Shakespeareâs Sonnets
In human culture there are certain numbers of special importance. They are mostly used in old and modern writings as âsacred numbersâ of religious and literary significance. They are present in the Greek myths, in Egyptian Pharaonic culture, in ancient Persian, in the Indian culture, and in Arab traditions; then (Islamic) culture as well as in the Biblical Western culture. These numbers are of two kinds: even and uneven or odd. The odd numbers 1, 3, 5, 7and 9 play a far more important part than the even numbers. One is Deity, three the Trinity, five the chief division, seven is the sacred number, and nine is three times three. These numbers have good function and been looked at as âSacredâ or âPerfectâ numbers either of good omen or evil. There is another forth number, which is â10â, it comes mainly in Jewish and Islamic education in very few cases having similar religious suggestion. Shakespeare has used the number Ten in Sonnet 6 Then let not winter's ragged hand deface. âSacred Numbersâ have become a part of religion and even of modern belief, and mostly represented in the popular rituals. Shakespeare has used the âSacred Numbersâ in his works either prose or poetry, and this article is restricted to deal only with three Shakespearean sonnets where I imagine Shakespeare reciting his Latin Rosary in a poetic religious tone and drawing the cross sign on his chest and on the forehead of his sonnets in order to invoke divine protection. It seems that Shakespeareâs date of birth and death (1564 -1616) carries a certain secret of his fondness for sacred numbers; thus: The sum of the date of his birth (1564=16) is doubled in the date of his death (1616)
Optical signatures of intrinsic electron localization in amorphous SiO2
We measure and analyse the optical absorption spectra of three silica glass samples irradiated with 1 MeV electrons at 80 K, where self-trapped holes are stable, and use ab initio calculations to demonstrate that these spectra contain a signature of intrinsic electron traps created as counterparts to the holes. In particular, we argue that optical absorption bands peaking at 3.7, 4.7, and 6.4âeV belong to strongly localised electrons trapped at precursor sites in amorphous structure characterized by strained SiâO bonds and OâSiâO angles greater than 132°. These results are important for our understanding of the properties of silica glass and other silicates as well as the reliability of electronic and optical devices and for luminescence dating
A new inversion free iteration for solving the equation X+Aâ X-1A=Q
AbstractIn this paper, we introduce a new inversion free variant of the basic fixed point iteration method for obtaining a maximal positive definite solution of the nonlinear matrix equation X+Aâ
X-1A=Q. It is more accurate than Zhan's algorithm (J. Sci. Comput. 17 (1996) 1167) and has less number of operations than the algorithm of Guo and Lancaster (Math. Comput. 68 (1999) 1589). We derive convergence conditions of the iteration and existence conditions of a solution to the problem. Finally, we give some numerical results to illustrate the behavior of the considered algorithm
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Novel salted anionic-cationic polymethacrylate polymer blends for sustained release of acidic and basic drugs
Background: Since a unique matrix tablet formulation that independently controls the release of various drug types is in a great demand, the objective of this research was to develop a sustained release matrix tablet as a universal dosage form using a binary mixture of the salt forms of Eudragit polymers rather than their interpolyelectrolyte complexes.
Methods: Tablets were prepared by wet granulation and compressed at different compression forces, depending on drug type. Dissolution tests were conducted using USP XXII rotating paddle apparatus at 50 rpm at 37°C in consecutive pH stages.
Results: Tablets containing Ibuprofen (IB) as a model acidic drug and Metronidazole (MD) as a model basic drug showed controlled/sustained release behavior. For IB tablets containing 80% Ibuprofen and 5% (w/w) polymeric combination; the time for 50% of the drug release was about 24 hours compared to 8.5 hours for plain tablets containing 80% IB. In case of MD, the drug release extended to about 7 hours for tablets containing 80% MD and 5% (w/w) polymeric combination, compared to about 1 hour for plain tablets containing 80% MD. In terms of extending the release of medications, the dissolution profiles of the tablets containing polymeric salts forms were found to be statistically superior to tablets prepared by direct compression of the polymers in their powdered base forms, and superior to tablets containing the same polymers granulated using isopropyl alcohol.
Conclusion: The findings indicated the significance of combining the polymers in their salt forms in controlling the release of various drug types from matrices
Bacterial Exopolysaccharides as New Natural Coagulants for Surface Water Treatment
Abstract: Coagulation-flocculation step is one of the most important steps during surface w ate r tre atm e n t. Che m ic al co ag ul an ts are o rdin ary use d such as al um . Howe ve r, the se chemical coagulants are dangerous to environment and human health. Natural coagulants derived from natural sources receive much attention during last years. This study aimed to isolate new bacterial exopolysaccharides from Bacillus licheniformis, B. insolitus and B. alvei to be used as natural coagulants during coagulation-flocculation process. Efficiency of extracted bacterial exopolysaccharides was examined through removal ability of bacterial indicators and some physicochemical parameters of River Nile water samples. Bacterial exopolysaccharides showed great removal percent when used as sole coagulant materials. Addition of alum to bacterial exopolysaccharides enhance removal efficiency
Fuel cell as an effective energy storage in reverse osmosis desalination plant powered by photovoltaic system
A hybrid renewable energy systems (HRESs) comprises of photovoltaic (PV), and self-charging fuel cells (SCFC) is designed for securing electrical energy required to operate brackish water pumping (BWP) and reverse osmosis desalination (RO) plant of 150âŻm3âŻd-1 for irrigation purposes in remote areas. An optimal configuration of the proposed design is determined based on minimum cost of energy (COE) and the minimum total net present cost (NPC). Moreover, a comparison with a stand-alone diesel generation (DG) or grid extension is carried out against the optimal configuration of PV/SCFC HRES. The modeling, simulation, and techno-economic evaluation of the different proposed systems, including the PV/SCFC system are done using HOMER software. Results show that PV array (66âŻkW), FC (9âŻkW), converter (25âŻKW) âElectrolyzer (15âŻkW), Hydrogen cylinder (70âŻkg) are the viable economic option with a total NPC of 0.062 unit cost of electricity. The COE for the stand-alone DG system is 0.206 $/kWh, which is 69.90% higher than that of the PV/SCFC system. The PV/SCFC system is cheaper than grid extension. This study opens the way for using a fuel cell as an effective method for solving the energy intermittence/storage problems of renewable energy sources
Modelling dependency networks to inform data structures in BIM and smart cities
The pervasive deployment of "smart city" and "smart building" projects in cities world-wide is driving innovation on many fronts including; technology, telematics, engineering and entrepreneurship. This paper focuses on the technical and engineering perspectives of BIM and smart cities, by extending building and urban morphology studies as to respond to the challenges posed by Big Data, and smart infrastructure. The proposed framework incorporates theoretical and modelling descriptions to verify how network-based models can act as the backbone skeletal representation of both building and urban complexity, and yet relate to environmental performance and smart infrastructure. The paper provides some empirical basis to support data information models through building dependency networks as to represent the relationships between different existing and smart infrastructure components. These dependency networks are thought to inform decisions on how to represent building and urban data sets in response to different social and environmental performance requirements, feeding that into void and solid descriptions of data maturity models. It is concluded that network-based models are fundamental to comprehend and represent the complexity of cities and inform urban design and public policy practices, in the design and operation phases of infrastructure projects
Management of arrhythmogenic right ventricular cardiomyopathy
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disease characterised by fibrofatty replacement of the ventricular myocardium due to specific mutations, leading to ventricular arrhythmias and sudden cardiac death. Treating this condition can be challenging due to progressive fibrosis, phenotypic variations and small patient cohorts limiting the feasibility of conducting meaningful clinical trials. Although widely used, the evidence base for anti-arrhythmic drugs is limited. Beta-blockers are theoretically sound, yet their efficacy in reducing arrhythmic risk is not robust. Additionally, the impact of sotalol and amiodarone is inconsistent with studies reporting contradictory results. Emerging evidence suggests that combining flecainide and bisoprolol may be efficacious.Radiofrequency ablation has shown some potential in disrupting ventricular tachycardia circuits, with combined endo and epicardial ablation yielding better results which could be considered at the index procedure. In addition, stereotactic radiotherapy may be a future option that can decrease arrhythmias beyond simple scar formation by altering levels of Nav1.5 channels, Connexin 43 and Wnt signalling, potentially modifying myocardial fibrosis.Future therapies, such as adenoviruses and GSk3b modulation, are still in early-stage research. While implantable cardioverter-defibrillator implantation is a key intervention for reducing arrhythmic death, the risks of inappropriate shocks and device complications must be carefully considered
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