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1.
Summary The number and positions of the i.r. active modes in ethylenediamine complexes of M(SO3Cl)2 (M = Mn, Fe, Co, Ni or Cu) suggest that the SO3Cl– anion is covalently bound in these non-electrolytic complexes. Magnetic moments and ligand field data suggest that each SO3Cl– group is monodentate, giving an octahedral geometry around the metal ions. 相似文献
2.
Norimah Yusof Asnah Hassan M.N. Firdaus Abd Rahman Suzina A. Hamid 《Radiation Physics and Chemistry》2007,76(11-12):1756-1759
Most of the tissue banks in the Asia Pacific region have been using ionising radiation at 25 kGy to sterilise human tissues for save clinical usage. Under tissue banking quality system, any dose employed for sterilisation has to be validated and the validation exercise has to be a part of quality document. Tissue grafts, unlike medical items, are not produced in large number per each processing batch and tissues relatively have a different microbial population. A Code of Practice established by the International Atomic Energy Agency (IAEA) in 2004 offers several validation methods using smaller number of samples compared to ISO 11137 (1995), which is meant for medical products. The methods emphasise on bioburden determination, followed by sterility test on samples after they were exposed to verification dose for attaining of sterility assurance level (SAL) of 10−1. This paper describes our experience in using the IAEA Code of Practice in conducting the validation exercise for substantiating 25 kGy as sterilisation dose for both air-dried amnion and those preserved in 99% glycerol. 相似文献
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Improved Spectral Coverage and Fluorescence Quenching in Donor–acceptor Systems Involving Indolo[3‐2‐b]carbazole and Boron‐dipyrromethene or Diketopyrrolopyrrole 下载免费PDF全文
Adis Khetubol Sven Van Snick Melissa L. Clark Eduard Fron Eduardo Coutiño‐González Arvid Cloet Koen Kennes Yuliar Firdaus Maarten Vlasselaer Volker Leen Wim Dehaen Mark Van der Auweraer 《Photochemistry and photobiology》2015,91(3):637-653
A novel π‐conjugated triad and a polymer incorporating indolo[3,2‐b]‐carbazole (ICZ) and 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) were synthesized via a Sonogashira coupling. Compared to the parent BODIPY the absorption and fluorescence spectrum were for both compounds broader and redshifted. The redshift of the fluorescence and the decrease of the fluorescence quantum yield and decay time upon increasing solvent polarity were attributed to the formation of a partial charge‐transfer state. Upon excitation in the ICZ absorption band the ICZ fluorescence was quenched in both compounds mainly due to energy transfer to the BODIPY moiety. In a similar ICZ–π–DPP polymer (where DPP is diketopyrrolopyrrole), a smaller redshift of the absorption and fluorescence spectra compared to the parent DPP was observed. A less efficient quenching of the ICZ fluorescence in the ICZ–π–DPP polymer could be related to the unfavorable orientation of the transition dipoles of ICZ and DPP. The rate constant for energy transfer was for all compounds an order of magnitude smaller than predicted by Förster theory. While in a solid film of the triad a further redshift of the absorption maximum of nearly 100 nm was observed, no such shift was observed for the ICZ–π–BODIPY polymer. 相似文献
4.
Mohammad Shakir Shahul Hameed Farha Firdaus Saji P. Varkey 《Transition Metal Chemistry》1995,20(2):142-143
Summary Adducts of dichlorosulphato bis(1,3-propylenediamine)-metal(II) complexes with dialkyltin dichlorides, [R2Sn(MeCN) 2]2[M(NH(CH2)3NH)2(SO3Cl)2] (M = Cr, Fe, Co, Ni or Cu; R = Me or n-Bu) have been prepared. The positive shift in the symmetric SO3 stretch and splitting of the doubly degenerate (E) modes in their i.r. spectra suggest a covalent linkage for the SO3Cl– group. The adducts are non-electrolytes; magnetic moments and ligand field data suggest that each SO3Cl– group is monodentate, generating an octahedral geometry around the metal ions, except for NiII where tetragonal distortion is observed.Author to whom all correspondence should be directed. 相似文献
5.
Firdaus Jahan Vinod Kumar Garima Rawat R. K. Saxena 《Applied biochemistry and biotechnology》2012,167(5):1157-1171
This study presents the production of bacterial cellulose (BC) by a bacterium isolated from a rotten fruit and its process optimization. Here, isolation and screening of potent cellulose producers were carried out from different natural sources, viz., soil, rotten fruits, and vegetables and vinegar. A total of 200 bacterial isolates were obtained, which were screened for cellulose production using Hestrin?CSchramm medium. A novel and potent cellulose-producing bacterium was newly isolated from a rotten fruit and identified as Gluconacetobacter sp. F6 through 16S ribosomal DNA sequencing and morphological, cultural, and biochemical characteristics. After optimization of culture conditions, including pH, temperature, agitation, carbon/nitrogen sources, and inducers, the BC production was greatly increased from 0.52 to 4.5?g/l (8.65-fold increase). The optimal culture medium contained 1% (w/v) glucose, 1.5% (w/v) yeast extract, 0.5% (w/v) peptone, 0.27% (w/v) disodium hydrogen phosphate, 0.115% (w/v) citric acid, and 0.4% (w/v) ethanol. BC produced was analyzed for the presence of cellulose fibrils by epiflourescent microscopy using Calcofluor white stain and scanning electron microscopy and confirmed by NMR. There are very scanty reports about the optimization of BC production by bacteria isolated from rotten fruits. 相似文献
6.
Mohamad Firdaus Mohamad Yusop Mohd Azmier Ahmad Nur Ayshah Rosli Mohd Edeerozey Abd Manaf 《Arabian Journal of Chemistry》2021,14(6):103122
This study assesses the performance of optimized acacia wood-based activated carbon (AWAC) as an adsorbent for methylene blue (MB) dye removal in aqueous solution. AWAC was prepared via a physicochemical activation process that consists of potassium hydroxide (KOH) treatment, followed by carbon dioxide (CO2) gasification under microwave heating. By using response surface methodology (RSM), the optimum preparation conditions of radiation power, radiation time, and KOH-impregnation ratio (IR) were determined to be 360 W, 4.50 min, and 0.90 g/g respectively, which resulted in 81.20 mg/g of MB dye removal and 27.96% of AWAC’s yield. Radiation power and IR had a major effect on MB dye removal while radiation power and radiation time caused the greatest impact on AWAC’s yield. BET surface area, mesopore surface area, and pore volume of optimized AWAC were found to be 1045.56 m2/g, 689.77 m2/g, and 0.54 cm3/g, respectively. Adsorption of MB onto AWAC followed Langmuir and pseudo-second order for isotherm and kinetic studies respectively, with a Langmuir monolayer adsorption capacity of 338.29 mg/g. Mechanism studies revealed that the adsorption process was controlled by film diffusion mechanism and indicated to be thermodynamically exothermic in nature. 相似文献
7.
Firdaus E. Udwadia 《International Journal of Non》1996,31(6):951-958
This paper presents a unified framework from which emerge the Lagrange equations, the Gibbs-Appell Equations and the Generalized Inverse Equations for describing the motion of constrained mechanical systems. The unified approach extends the applicability of the first two approaches to systems where the constraints are non-linear functions of the generalized velocities and are not necessarily independent. Furthermore, the approach leads to the Explicit Gibbs-Appell Equations. 相似文献
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Firdaus E. Udwadia 《Applied mathematics and computation》2010,217(3):1253-1265
This paper deals with an explanation of a paradox posed by Hamel in his 1949 book on Theoretical Mechanics. The explanation deals with the foundations of mechanics and points to new insights into analytical dynamics. 相似文献
10.
Adam A. Y. Oumer A. N. Najafi G. Ishak M. Firdaus M. Aklilu T. B. 《Journal of Thermal Analysis and Calorimetry》2020,139(4):2739-2768
Journal of Thermal Analysis and Calorimetry - The need for better thermal–hydraulic performance of heat exchangers remains the primary reason for further improving the design of heat... 相似文献