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Method B (method + b)
Selected AbstractsQuantifying prehistoric soil erosion,A review of soil loss methods and their application to a Celtic square enclosure (Viereckschanze) in Southern GermanyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2007Matthias Leopold This paper discusses the strengths and weaknesses of three different methods for quantifying prehistoric soil erosion. Method A estimates erosion by determining the amount of colluvium stored downhill. Method B involves reconstructing a former erosion surface using truncated soil horizons. Method C compares the elevation of a paleosol beneath an earthwork with the modern surface in the surrounding area. Each method was applied to a Celtic earthwork (Viereckschanze) at Poign (near Regensburg) in Southern Germany in order to cross-check the different results. For an erosion area of 3.6 ha and during 300 years of agricultural usage, Method A calculates a minimum erosion rate of 20.8 t/ha/a. Method B computes 10 t/ha/a of soil loss. Method C yields the highest rate of erosion with 24.2 t/ha/a. We have confidence in Method C, which implies an underassesment of soil loss in using methods A or B. © 2007 Wiley Periodicals, Inc. [source] Data Sparseness and On-Line Pretest Item Calibration-Scaling Methods in CATJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 3 2002Jae-Chun Ban The purpose of this study was to compare and evaluate three on-line pretest item calibration-scaling methods (the marginal maximum likelihood estimate with one expectation maximization [EM] cycle [OEM] method, the marginal maximum likelihood estimate with multiple EM cycles [MEM] method, and Stocking's Method B) in terms of itern parameter recovery when the item responses to the pretest items in the pool are sparse. Simulations of computerized adaptive tests were used to evaluate the results yielded by the three methods. The MEM method produced the smallest average total error in parameter estimation, and the OEM method yielded the largest total error. [source] Prediction of human blood-to-plasma drug concentration ratioBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 5-6 2010Takahide Uchimura Abstract The objective of this study was to predict Rb (blood/plasma ratio) in humans using a simple method. Human and rat Rb and free fraction in plasma (fp) values were obtained from the literature. The ratio of total red blood cell concentration to the free concentration in plasma (Kb) was calculated using fp and Rb. Four methods were used for the prediction of Rb: (A) use of rat Rb; (B) use of Rb calculated from rat Kb and human fp; (C) correlation of human log ((1,fp)/fp) and human log Kb; and (D) correlation of log D with human log Kb. The Rb of 96 compounds in humans ranged from 0.52 to 2.00, with an average of 0.89. A significant correlation was observed among human log Kb, human log ((1,fp)/fp), and log D; however, no obvious correlation was observed among human Rb, human log ((1,fp)/fp), and log D. The errors within 1.25-fold for methods A,D were 68.3%, 77.6%, 61.5% and 64.8%, respectively. All predictive methods considered here were superior to the use of the average value of human Rb or Rb=1. Rat Rb corrected by human fp improved the accuracy of the prediction. Method B was the most accurate of the four methods. Copyright © 2010 John Wiley & Sons, Ltd. [source] Simultaneous determination of metronidazole and spiramycin in bulk powder and in tablets using different spectrophotometric techniquesDRUG TESTING AND ANALYSIS, Issue 1 2010Fatma I. Khattab Abstract Metronidazole (MZ) is an anti-infective drug used in the treatment of anaerobic bacterial and protozoa infections in humans. It is also used as a vetinary antiparasitic drug. Spiramycin (SP) is a medium-spectrum antibiotic with high effectiveness against Gram-positive bacteria. Three simple, sensitive, selective and precise spectrophotometric methods were developed and validated for the simultaneous determination of MZ and SP in their pure form and in pharmaceutical formulations. In methods A and B, MZ was determined by the application of direct spectrophotometry and by measuring its zero-order (D0) absorption spectra at its ,max = 311 nm. In method A, SP was determined by the application of first derivative spectrophotometry (D1) and by measuring the amplitude at 218.3 nm. In method B, the first derivative of the ratio spectra (DD1) was applied, and SP was determined by measuring the peak amplitude at 245.6 nm. Method C entailed mean centring of the ratio spectra (MCR), which allows the determination of both MZ and SP. The methods developed were used for the determination of MZ and SP over a concentration range of 5,25 µg ml,1. The proposed methods were used to determine both drugs in their pure, powdered forms with mean percentage recoveries of 100.16 ± 0.73 for MZ in methods A and B, 101.10 ± 0.90 in method C, 100.09 ± 0.70, 100.02 ± 0.88 and 100.49 ± 1.26 for SP in methods A, B and C, respectively. The proposed methods were proved using laboratory-prepared mixtures of the two drugs and were successfully applied to the analysis of MZ and SP in tablet formulation without any interference from each other or from the excipients. The results obtained by applying the proposed methods were compared statistically with a reported HPLC method and no significant difference was observed between these methods regarding both accuracy and precision. Copyright © 2010 John Wiley & Sons, Ltd. [source] Wet granulation as innovative and fast method to prepare controlled release granules based on an ion-exchange resinJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2008Beatrice Albertini Abstract The goal of this work was to evaluate the suitability of wet granulation as an innovative and fast method for the preparation of granules containing a drug,resin complex (resinate), having cholestyramine as resin and potassium diclofenac (KD) as drug. Resinate and granules were prepared directly by steam granulation in high shear mixer (method A), using two different amount of resin (granules 1 and 2). For comparison granules 1 were also prepared by conventional batch method followed by steam granulation (method B). All granules showed quite irregular shape, main size fractions between 75 and 500 µm, good flowability and uniform KD distribution. Granules 1A exhibited controlled release profiles at pH 7.4, while granules 2A showed a burst effect due to KD free crystals. FT-IR studies confirmed the complete complexation between resin and KD during the granulation process with method A for granules 1. Finally, the dissolution test of granules 1A in different media revealed a controlled drug release in 12 h, providing the utility of this system for enteric drug delivery. Granules 1B evidenced similar characteristics to those of granules 1A; the drawback of the multistep procedure was related to the long processing time. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1313,1324, 2008 [source] Combination of Er:YAG laser and photodynamic therapy in the treatment of nodular basal cell carcinomaLASERS IN SURGERY AND MEDICINE, Issue 2 2008Roman, mucler PhD Abstract Backgrounds and Objectives Photodynamic therapy (PDT), via topical aminolevulinic acid (ALA) is an effective treatment for basal cell carcinomas not exceeding a depth of 2 mm. This limits the treatment of basal cell carcinoma (non-melanoma skin cancer) to superficial forms and nodular therapy (only in aesthetically desired locations). This paper addresses the effectiveness of reducing tumor mass via initial Er:YAG laser ablation to depths that are therapeutically responsive to PDT with ALA. Study Design/Materials and Methods This study compared three methods for the treatment of recurring nodular basal cell carcinomas (r nBCC). Method A utilized PDT with topical application of ALA methyl ester, method B with solitary Er:YAG laser ablation, and method C combined Er:YAG laser ablation reducing tumor size below 2 mm (method B) with subsequent ALA methyl ester PDT (method A). All three methods were used to treat to each patient, all subjects presenting with three or more basal cell carcinomas in order to eliminate differences in patient responsiveness to treatment. Patients were monitored and interviewed at 3, 6, and 12 month intervals to examine the progress of tumor elimination, aesthetic results as well as the patient's preference of treatment method. In all, 286 patients were treated, of whom 194 were checked at the prescribed intervals and then evaluated. Results Statistically, the combination therapy demonstrated the most effective treatment at all time intervals, with a final efficacy of 98.97% versus 94.85% (PDT only) and 91.75% (Er:YAG laser only). The combined method also provided the best aesthetic results (scale: 1,best; 4,worst) of 1.23±1.23, compared to 1.67±0.76 (PDT only) and 1.83±0.95 (Er:YAG laser only). Conclusions Although 67% patients preferred solitary Er:YAG laser treatment over the PDT method (20%) and the combined treatment (13%), because of the simplicity of the treatment, the combination therapy has proven to be both clinically and aesthetically superior. Solitary Er:YAG laser ablation will remain however a fast, effective, and economical treatment alternative for simple manifestations of superficial basal cell carcinoma and has replaced PDT for uncomplicated cases at our facility. The combination of Er:YAG laser ablation and ALA,PDT aspires to be therapy of choice for BCC. Lesers Surg. Med. 40:153,158, 2008. © 2008 Wiley-Liss, Inc. [source] Modified technique of ureteroureterostomy in rat kidney transplantationMICROSURGERY, Issue 4 2004Alexander Pietsch Dr. Med. Different strain combinations of rats are available to study immunological and transplant-related problems in the models of kidney transplantation. Although numerous modifications of surgical techniques for ureteric reconstruction are evaluated in order to reduce complications and to extend long-term survival, ureteric complications still occur frequently, especially when the difference in diameter of both donor and host ureters is disproportionate. Instead of using the current nonsplinted ureteroureterostomy (method A), a versatile and rapid technical modification (method B) was developed to perform reconstruction of ureters with disproportionate diameters. The overall incidence of ureteric complications was 80% (8/10) using method A, whereas this rate was significantly reduced to 15% (3/20) using method B (P < 0.001). Our modification proves the feasibility of nonsplinted ureteroureterostomy in a technical, highly demanding rat model of kidney transplantation with an acceptable rate of ureteric complication, considering the disproportionate difference in diameter between the host and donor ureters. © 2004 Wiley-Liss, Inc. [source] Multiple Inert Gas Elimination Technique For Determining Ventilation/Perfusion Distributions In Rat During Normoxia, Hypoxia And HyperoxiaCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2001V Alfaro SUMMARY 1. The use of the multiple inert gas elimination technique (MIGET) in quantifying ventilation/perfusion distributions (V,A/Q,) in small animals, such as the rat, may cause results to be biased due to haemodilution produced by the large volume of liquid infused intravenously. 2. We tested two methods of administering inert gases in rats using the MIGET: (i) standard continuous intravenous administration of inert gases (method A); and (ii) a new method based on the physicochemical properties of each inert gas (method B). This method included acute simultaneous inert gas administration using three pathways: inhalation, intravenous infusion and rectal infusion. Both MIGET methods were applied to obtain data while breathing three different inspiratory fractions of oxygen (FIO2): normoxia, hypoxia and hyperoxia. 3. Inert gas levels obtained from blood or expired air samples were sufficient for chromatographic measurement, at least during a 2 h period. The V,A/Q, distributions reported using both methods were acceptable for all the physiological conditions studied; therefore, the alternative method used here may be useful in further MIGET studies in rats because haemodilution resulting from continuous intravenous infusion of less-soluble gases can be avoided. 4. Normoxic rats showed lower mean values of the V,A/Q, ratio of ventilation distribution and higher mean values of the V,A/Q, ratio of perfusion distribution with the usual method of inert gas administration (method A). These non-significant differences were observed under almost all physiological conditions studied and they could be caused by haemodilution. Nevertheless, the effect of interindividual differences cannot be discarded. An additional effect of the low haematocrit on cardiovascular changes due to low FIO2, such as pulmonary vasoconstriction or increased cardiac output, may explain the lower dispersion of perfusion distributions found in group A during hypoxia. 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