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A preconcentration technique for manganese in water samples by adsorption on a tantalum wire was investigated for tungsten tube atomizer electrothermal atomization atomic absorption spectrometry. After preconcentration, the tantalum wire was directly inserted into the tungsten tube atomizer. In the preconcentration (adsorption) process for manganese, the optimal immersion time was 60 sec and the best pH was 9. Under the optimal conditions, the detection limit for manganese by the tantalum wire preconcentration method was 6.3 pg mL−1 (3S/N) and the relative standard deviation was 7.6%. The influences of concomitants on the preconcentration of manganese were evaluated. Even though 103 to 104-fold excess of matrix elements existed in aqueous solution, the manganese absorption signal was not significantly affected by the matrix elements. The method with preconcentration on a tantalum wire was applied to the determination of manganese in river waters and proved to be sensitive, simple, and convenient. Because this preconcentration method can be utilized in the in-situ treatment of trace manganese in environmental water samples, it was unnecessary to carry the water samples to the analytical work place. The technique was shown to be useful for the determination of manganese in environmental water samples at 0.1–1 g L−1 levels.

A preconcentration method of lead in waters by adsorption on a tantalum wire was developed for electrothermal atomization atomic absorption spectrometry with a tungsten tube atomizer. After the preconcentration, the tantalum wire was directly inserted into the tungsten tube atomizer. In the preconcentration (adsorption) process for lead, the optimal immersing time was 90 s and the best pH was 4. Under the optimal conditions, the detection limit for lead by the tantalum wire preconcentration method was 6.0 pg mL − 1 (3S/N) and the relative standard deviation was 6.1%. The influences of large amounts of concomitants on the preconcentration of lead were evaluated. Even though 10 3 to 10 4 -fold excess of matrix elements existed in aqueous solution, the lead absorption signal was not significantly affected by the matrix elements. The method with preconcentration on a tantalum wire was applied to the determination of lead in river waters and proved to be sensitive, simple, and convenient. Because this preconcentration method can be utilized in the in-situ treatment of trace lead in environmental water samples, it was unnecessary to carry the water samples to the analytical work place. The present technique was shown to be useful for the determination of lead in environmental water samples at 0.1−1 μg L − 1 .

Noise is considered as a sound of independent loudness and an environmental pollutant, produces in conjunction with various anthropogenic activities and becomes hazardous to all living being. In this aspect, the research determined a noise inventory for urban and rural settings in Khulna District of Bangladesh and identified the relevant sources from which the noise produced such as urbanization, industrialization and motorization activities. Sound level meters and questionnaires were used for noise measurement and public perceptions regarding noise pollution in 2005 respectively. The research finds out higher values than the Bangladesh standard almost every sensitive areas like hospitals and schools. The identified noise-levels have the significant impacts on physical and mental health of the stakeholders particularly to the senior citizens, students and children. In addition, the research makes a comparison of noise levels between urban and rural settings, where the comparison shows that noise-levels are closely related with traffic volume, vehicles number, its quality and composition such as trucks, buses, auto rickshaws, construction activities, various machineries and other such tools and activities. The research also analyzes the people’s perception on the noise effects of both urban and rural areas to find out a sustainable remedial measure. The health effects include suffering from headache, bad-temper, sleeplessness, aggravation, hearing problems and other relevant diseases.

The determination of alkali metal chloride in river waters by sequential molecular vapor elution analysis (SMVEA) using a molecular absorption detector (MA) is reported. An improved molybdenum column was developed for SMVEA. An optimum flow rate of carrier gas (pure argon or nitrogen) for separation of metal vapors was 12.0 ml min −1 . Lithium chloride and sodium chloride peaks completely separated from potassium, rubidium, and cesium chlorides but CaCl 2 , FeCl 2 , MgCl 2 , and MnCl 2 peaks did not appear at a column temperature of 1000 °C and vaporization temperature of 1000 °C. The appearing order of these metal chlorides was LiCl, NaCl, KCl, RbCl, and CsCl. It was not understood by considering the boiling points of these metal chlorides. The delay of appearing time is due to an interaction between the molecular vapors and inside surface of the column. Under the experimental conditions, the number of theoretical plates was 247 for LiCl and 268 for NaCl in the improved column. Under the optimal experimental conditions, river waters were analyzed for lithium and sodium chlorides. The analytical results agreed well with the recoveries were in the range of 94–105%. By SMVEA, it was found that lithium and sodium chlorides in waters were determined without interference of matrix elements, no chemical treatment for river water samples.

Because lead pollution was recently reported in the fresh water Dhanmondi Lake, in Bangladesh the concentration of selected elements in the flesh of three species of fish, Tilapia nilotica , Cirrhina mrigala and Clarius batrachus , were investigated. The elemental concentrations were determined using atomic absorption spectrometry and the following results (in μg/g-dry weight) were obtained: calcium 4999, sodium 3183, magnesium 2193, iron 131, zinc 60.1, manganese 17.5, copper 5.07, lead 2.08 and nickel 1.91. Since the commission regulation setting maximum lead level for the muscle meat of fish, released from the European Communities (EC), followed by the European Union (EU), is 0.2 mg/kg wet weight, corresponding to 0.96 μg/g dry weight, considerable attention should be paid to the lead content in freshwater fish species in Bangladesh. Furthermore, continuous monitoring of heavy metal concentration in edible freshwater fish will be needed in Bangladesh.

A preconcentration method for silver in environmental waters involving adsorption on a tungsten wire, followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The optimal immersing time was 90s. The best pH for the adsorption of silver was 3. Under the optimal conditions, the detection limit for silver by the tungsten wire preconcentration method was 5.0ngl(-1) (3S/N) and the relative standard deviation was 8.2%. The effects of large amounts of concomitants on the preconcentration of silver were evaluated. Even though 10(3)- to 10(4)-fold excess of matrix elements existed in water, the silver response was not significantly affected by the matrix elements. The method with preconcentration on a tungsten wire was applied to the determination of silver in waters and proved to be sensitive, simple, and convenient. This adsorption method can be utilized in in situ sampling of ultra-trace silver in environmental samples (waters). Furthermore, after sampling it is easy to carry and store the tungsten wire without contamination for a long time.

Ibrahim Cardiac Medical Journal 2011; 1(2): 7-9 DOI: http://dx.doi.org/10.3329/icmj.v1i2.13544

Ultrasonic slurry sampling electrothermal atomic absorption spectrometry with a molybdenum tube atomizer has been applied for the determination of cadmium in vegetable samples in Bangladesh. The suspension-stabilizing medium was 10% glycerol solution. The optimum pyrolysis temperature was 300°C. The detection limit was 13 fg (3S/N). Matrix element interference was studied and it was found that thiourea as a chemical modifier eliminated the interference. The results for the determination of cadmium in vegetable samples by the proposed method were in good agreement with those measured in dissolved acid-digested samples. The method enables rapid calibration, and simple and rapid analysis of cadmium in vegetable samples at low cost.

An ultrasonic slurry sampling electrothermal atomic absorption spectrometric method with a molybdenum tube atomizer has been developed for the determination of copper in herbal medicine samples. Glycerol solution (10%) was used as the slurry medium. The optimum pyrolysis temperature was 760 °C. The detection limit was 72 fg (3×S/N ratio). Matrix element interference was investigated and it was found that glycerol as a chemical modifier eliminated the interference. The amounts of copper in herbal medicines determined by the method proposed are in good accordance with those measured in dissolved acid-digested samples. The method enables rapid calibration, and simple and rapid analysis of copper in herbal medicine samples at low cost.

A preconcentration method for antimony in waters involving adsorption on a tantalum wire, followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The best pH for the adsorption of antimony was 2. The optimal immersing time was 120 s. Under the optimal conditions, the detection limit for antimony by the tantalum wire preconcentration method was 50 pg/mL (3S/N) and the relative standard deviation was 9.4%. The effects of large amounts of concomitants on the preconcentration of antimony were evaluated. Even though 103–104 fold excess of matrix elements existed in water, the antimony response was not significantly affected by the matrix elements. The method with preconcentration on a tantalum wire was applied to the determination of antimony in waters and proved to be sensitive, simple, and convenient. This adsorption method can be utilized in in-situ sampling of ultra-trace antimony in environmental samples (water). Furthermore, after sampling it is easy to carry and store the tantalum wire without contamination for a long time. The technique developed was shown to be useful for the determination of Sb in waste waters at the 1–5 µg/L level.

High-quality radiation therapy using highly conformal dose distributions and image-guided techniques requires optimum machine delivery performance. In this work, a monitoring system for multileaf collimator (MLC) performance, integrating semiautomated MLC quality control (QC) tests and statistical process control tools, was developed. The MLC performance monitoring system was used for almost a year on two commercially available MLC models. Control charts were used to establish MLC performance and assess test frequency required to achieve a given level of performance. MLC-related interlocks and servicing events were recorded during the monitoring period and were investigated as indicators of MLC performance variations.The QC test developed as part of the MLC performance monitoring system uses 2D megavoltage images (acquired using an electronic portal imaging device) of 23 fields to determine the location of the leaves with respect to the radiation isocenter. The precision of the MLC performance monitoring QC test and the MLC itself was assessed by detecting the MLC leaf positions on 127 megavoltage images of a static field. After initial calibration, the MLC performance monitoring QC test was performed 3-4 times/week over a period of 10-11 months to monitor positional accuracy of individual leaves for two different MLC models. Analysis of test results was performed using individuals control charts per leaf with control limits computed based on the measurements as well as two sets of specifications of ± 0.5 and ± 1 mm. Out-of-specification and out-of-control leaves were automatically flagged by the monitoring system and reviewed monthly by physicists. MLC-related interlocks reported by the linear accelerator and servicing events were recorded to help identify potential causes of nonrandom MLC leaf positioning variations.The precision of the MLC performance monitoring QC test and the MLC itself was within ± 0.22 mm for most MLC leaves and the majority of the apparent leaf motion was attributed to beam spot displacements between irradiations. The MLC QC test was performed 193 and 162 times over the monitoring period for the studied units and recalibration had to be repeated up to three times on one of these units. For both units, rate of MLC interlocks was moderately associated with MLC servicing events. The strongest association with the MLC performance was observed between the MLC servicing events and the total number of out-of-control leaves. The average elapsed time for which the number of out-of-specification or out-of-control leaves was within a given performance threshold was computed and used to assess adequacy of MLC test frequency.A MLC performance monitoring system has been developed and implemented to acquire high-quality QC data at high frequency. This is enabled by the relatively short acquisition time for the images and automatic image analysis. The monitoring system was also used to record and track the rate of MLC-related interlocks and servicing events. MLC performances for two commercially available MLC models have been assessed and the results support monthly test frequency for widely accepted ± 1 mm specifications. Higher QC test frequency is however required to maintain tighter specification and in-control behavior.

The early detection of rebar corrosion in reinforced concrete is difficult using current methods. This pilot study investigated the viability of using nonlinear ultrasound to detect the effects of rebar corrosion in its early stages. The study utilized three accelerated corrosion specimens and one control specimen. Results showed that when corrosion developed in the area isonified by a Rayleigh wave, nonlinear parameters increased. As corrosion progressed, these nonlinear parameters also increased.

The preconcentration of chromium on tantalum wire followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The preconcentration is accomplished by adsorbing chromium on a tantalum wire. The optimal immersion time was 3 mm. The best pH for chromium adsorption was 3. Under optimal conditions, the detection limit was 15 pg mU1 (3 x SIN). The effects on the preconcentration of chromium by large amounts of contaminants were evaluated. Even though matrix elements existed in 10(3)-10(4)-fold excess in water, the chromium absorption signal was not affected by the matrix elements. The method with preconcentration on tantalum wire was applied to the determination of chromium in river water.

We studied the clinical, histologic and immunologic features of 32 pemphigus patients evaluated in Dhaka. The diagnosis was pemphigus vulgaris (PV) in 72% of cases, and pemphigus foliaceous (PF) in 28%, with male to female ratios of 1.3 : 1 and 1.25 : 1, respectively. Only 25% of PV patients had vesicles or bullae involving mucous membranes as the initial presentation. Direct (DIF) and indirect (IIF) immunofluorescence tests were positive in all 32 patients. The DIF testing of tissue demonstrated intercellular substance (ICS) deposition of IgG (59%) or IgG plus C3 (41%). Serum ICS antibody titers ranged from 1 : 20-40 in PV and from 1 : 10-20 in patients with PF. To our knowledge, this is the first report concerning the characteristics of pemphigus in Bangladesh.

政策分析プログラム / Policy Analysis Program, 論文審査委員: 園部 哲史（主査）, 大山 達雄, Jonna P. Estudillo, 大塚 啓二郎, 岡田 羊祐（一橋大学）