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AbstractSome cases of occurrence of matrix effects (mostly ion suppression) in protein‐precipitated plasma samples, and their influence on the validity of plasma concentrations and pharmacokinetic parameters, are discussed. The comparison of matrix effects using either electrospray (TurboIonspray, TISP) or atmospheric pressure chemical ionization (APCI) indicated that APCI is less prone to matrix effects. Nevertheless, TISP is usually the first choice of ionization technique since unknown thermally labile metabolites might be present in the plasma samples causing erroneous results. A high impact of ion suppression on the plasma concentrations after intravenous (i.v.) administration was found, depending on the drug formulation (vehicle). Since ion suppression caused significantly lower plasma concentrations (by a factor of up to 5.5) after i.v. dosing, the area under the curve (AUC) was underestimated and the plasma clearance was consequently erroneously high, with an impact on drug candidate selection. By simple stepwise dilution (e.g. 10‐fold and 50‐fold) of the supernatant of protein‐precipitated plasma samples, including all calibration and quality control samples, the matrix effects were recognized and eliminated. Copyright © 2003 John Wiley & Sons, Ltd.

AbstractSome cases of occurrence of matrix effects (mostly ion suppression) in protein‐precipitated plasma samples, and their influence on the validity of plasma concentrations and pharmacokinetic parameters, are discussed. The comparison of matrix effects using either electrospray (TurboIonspray, TISP) or atmospheric pressure chemical ionization (APCI) indicated that APCI is less prone to matrix effects. Nevertheless, TISP is usually the first choice of ionization technique since unknown thermally labile metabolites might be present in the plasma samples causing erroneous results. A high impact of ion suppression on the plasma concentrations after intravenous (i.v.) administration was found, depending on the drug formulation (vehicle). Since ion suppression caused significantly lower plasma concentrations (by a factor of up to 5.5) after i.v. dosing, the area under the curve (AUC) was underestimated and the plasma clearance was consequently erroneously high, with an impact on drug candidate selection. By simple stepwise dilution (e.g. 10‐fold and 50‐fold) of the supernatant of protein‐precipitated plasma samples, including all calibration and quality control samples, the matrix effects were recognized and eliminated. Copyright © 2003 John Wiley & Sons, Ltd.

Abstract An orange and an apple juice each containing 250–385 ppm tin were under suspicion of having caused an outbreak of food poisoning in Kuwait in 1967 but did not cause any toxic signs when fed to pigeons, cats and dogs. One cat out of 11 vomited when fed an orange juice containing 540 ppm tin derived from the container, and with juices containing 1370 ppm tin, 20–30% of the cats vomited but none of the dogs was affected. Fruit juices containing 2000 ppm tin caused vomiting in up to 40% of the cats. Modification of orange juices with a high tin content by addition of nitrate or ethanol or by adjustment of the pH from 3 to 6 did not affect the incidence of vomiting. No toxic signs were produced in rats given fruit juices containing added tin salts up to a level of 995 ppm or in rats and cats given aqueous solutions of tin salts (up to 1200 ppm tin) in citric acid. Solid foods containing tin derived from the containers up to the highest level obtainable (470 ppm) had no toxic effect when fed to dogs and cats. Five human volunteers showed no toxic signs after drinking fruit juices containing 498, 540 or 730 ppm tin derived from the containers, but all five had some gastro-intestinal disturbance after drinking a fruit juice containing 1370 ppm tin. A repeat experiment with the latter juice had no effect in four of the volunteers and only mild symptoms in the fifth. In rats and cats, there was no evidence of tin absorption 24 hr after ingestion of fruit juices containing high levels of tin. No tin was recovered from the urine and in the rats 99% was recovered from the faeces. Only minute amounts of tin could be found in the body, apart from the alimentary tract, of a rat that had been given orange juice with a high tin content ad lib. instead of drinking water for 7 days. It is concluded that toxic signs follow the drinking of tin-containing fruit juices by man and cats only with tin levels of approximately 1400 ppm and above, that there is no evidence from these experiments that toxicity is due to the absorption of tin and that the most likely cause is local irritation of the mucous membrane of the alimentary tract.

Abstract An orange and an apple juice each containing 250–385 ppm tin were under suspicion of having caused an outbreak of food poisoning in Kuwait in 1967 but did not cause any toxic signs when fed to pigeons, cats and dogs. One cat out of 11 vomited when fed an orange juice containing 540 ppm tin derived from the container, and with juices containing 1370 ppm tin, 20–30% of the cats vomited but none of the dogs was affected. Fruit juices containing 2000 ppm tin caused vomiting in up to 40% of the cats. Modification of orange juices with a high tin content by addition of nitrate or ethanol or by adjustment of the pH from 3 to 6 did not affect the incidence of vomiting. No toxic signs were produced in rats given fruit juices containing added tin salts up to a level of 995 ppm or in rats and cats given aqueous solutions of tin salts (up to 1200 ppm tin) in citric acid. Solid foods containing tin derived from the containers up to the highest level obtainable (470 ppm) had no toxic effect when fed to dogs and cats. Five human volunteers showed no toxic signs after drinking fruit juices containing 498, 540 or 730 ppm tin derived from the containers, but all five had some gastro-intestinal disturbance after drinking a fruit juice containing 1370 ppm tin. A repeat experiment with the latter juice had no effect in four of the volunteers and only mild symptoms in the fifth. In rats and cats, there was no evidence of tin absorption 24 hr after ingestion of fruit juices containing high levels of tin. No tin was recovered from the urine and in the rats 99% was recovered from the faeces. Only minute amounts of tin could be found in the body, apart from the alimentary tract, of a rat that had been given orange juice with a high tin content ad lib. instead of drinking water for 7 days. It is concluded that toxic signs follow the drinking of tin-containing fruit juices by man and cats only with tin levels of approximately 1400 ppm and above, that there is no evidence from these experiments that toxicity is due to the absorption of tin and that the most likely cause is local irritation of the mucous membrane of the alimentary tract.

Endocrinological research on wild animals inhabiting remote areas has been hampered by the need to store plasma samples at subzero temperatures. In an attempt to remedy this logistical issue, we here investigate the use of ethanol as an alternative to freezing for the preservation of steroid and indoleamine hormones in avian plasma. Known quantities of the steroids 5alpha-dihydrotestosterone (DHT), testosterone, 17beta-estradiol, corticosterone, and the indoleamine melatonin were added to a stripped pool of chicken plasma. Samples were either immediately frozen at -40 degrees C, or treated with pure ethanol. Ethanol-treated samples were either immediately frozen, or-to simulate storage conditions at various field locations-left sitting at room temperature for one to two months, or incubated at 36 degrees C for one month before all treatment groups were frozen at -40 degrees C. All samples were then analyzed by radioimmunoassay. For DHT and estradiol there were no differences among treatment groups suggesting that ethanol-treatment is as effective as immediate freezing in preserving plasma steroid concentrations. For testosterone, corticosterone and melatonin ethanol-treated samples differed significantly from immediately frozen samples suggesting that caution is needed when comparing absolute concentrations of hormones between samples preserved in different ways. However, differences among ethanol-treated samples in general were small, demonstrating the feasibility of this preservation method in the field at remote locations.

Endocrinological research on wild animals inhabiting remote areas has been hampered by the need to store plasma samples at subzero temperatures. In an attempt to remedy this logistical issue, we here investigate the use of ethanol as an alternative to freezing for the preservation of steroid and indoleamine hormones in avian plasma. Known quantities of the steroids 5alpha-dihydrotestosterone (DHT), testosterone, 17beta-estradiol, corticosterone, and the indoleamine melatonin were added to a stripped pool of chicken plasma. Samples were either immediately frozen at -40 degrees C, or treated with pure ethanol. Ethanol-treated samples were either immediately frozen, or-to simulate storage conditions at various field locations-left sitting at room temperature for one to two months, or incubated at 36 degrees C for one month before all treatment groups were frozen at -40 degrees C. All samples were then analyzed by radioimmunoassay. For DHT and estradiol there were no differences among treatment groups suggesting that ethanol-treatment is as effective as immediate freezing in preserving plasma steroid concentrations. For testosterone, corticosterone and melatonin ethanol-treated samples differed significantly from immediately frozen samples suggesting that caution is needed when comparing absolute concentrations of hormones between samples preserved in different ways. However, differences among ethanol-treated samples in general were small, demonstrating the feasibility of this preservation method in the field at remote locations.

Abstract Amorphous and microcrystalline silicon single layers and p–i–n solar cells were produced dynamically using an inline deposition system called “line source”. A highly uniform deposition of thin-film silicon layers with layer-thickness variations of less than ±5% was achieved. Amorphous and microcrystalline silicon single junction solar cells were dynamically fabricated with initial efficiencies of 8.3% and 6.3%, respectively. The dynamic deposition rate of these solar cells is 6.75 nm m/min in case of a-Si:H and 3.3 nm m/min for μc-Si:H. In this work it will be shown that an enhancement of the deposition rate up to 15.6 nm m/min during the i-layer deposition of a-Si:H solar cells has only a weak negative influence on the initial efficiencies of the cells. Further on, the effect of substrate velocity on solar cell characteristics of a-Si:H solar cells is investigated. Finally, a productivity estimation of the line source concept is presented.

Abstract Amorphous and microcrystalline silicon single layers and p–i–n solar cells were produced dynamically using an inline deposition system called “line source”. A highly uniform deposition of thin-film silicon layers with layer-thickness variations of less than ±5% was achieved. Amorphous and microcrystalline silicon single junction solar cells were dynamically fabricated with initial efficiencies of 8.3% and 6.3%, respectively. The dynamic deposition rate of these solar cells is 6.75 nm m/min in case of a-Si:H and 3.3 nm m/min for μc-Si:H. In this work it will be shown that an enhancement of the deposition rate up to 15.6 nm m/min during the i-layer deposition of a-Si:H solar cells has only a weak negative influence on the initial efficiencies of the cells. Further on, the effect of substrate velocity on solar cell characteristics of a-Si:H solar cells is investigated. Finally, a productivity estimation of the line source concept is presented.

Abstract Solutions containing hydrofluoric acid (HF), hydrochloric acid (HCl), and hydrogen peroxide (H2O2) were investigated as novel acidic, NOx-free etching mixtures for texturing of monocrystalline silicon wafers. High etch rates of up to 13.3 nm s−1 were observed at room temperature, which are comparable to the etch rates of KOH-IPA solutions. The silicon surface was investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), indicating pyramidal textures for diamond wire and SiC-slurry sawn as well as saw-damage etched (polished) wafers. Non-stirred baths generate random pyramidal structures while constantly stirred solutions generate novel random inverted pyramidal surface structures. The light trapping efficiency of wafers etched by the HF-HCl-H2O2 solutions was compared by UV/vis-reflectivity measurements to KOH/i-propanol specimens indicating lower reflectivities for the HF-HCl-H2O2-treated samples. Using the ‘wafer ray tracer’ (pvlighthouse.com) the light absorption properties of monomodal and random inverted pyramid structures were simulated and compared to well-known random and monomodal textures for PERC solar cells, clearly indicating the best performance for random inverted pyramids. Besides, simulation of a PERC solar cell on a roof top at our university was performed, indicating improved performance, especially for random inverted pyramid textures.