bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Headspace-Solid Phase Microextraction-Gas Chromatography Method to Determine Organohalogen Contamination in Drinking Water
Authors: Mariani Maurizio Boccacci , Giannetti Vanessa , Testani Elena , D'Aiuto Virginia
Published: February 2012

The formation of organohalogen compounds in waters treated by chlorination has drawn increasing scientific attention due to the potentially hazardous health effects of this class of substances. Today, chlorination is the most widely used technology for civil water disinfection. In this study, headspace- solid phase microextraction coupled with GC-electron capture detector was used to determine organohalogen compounds in drinking water sampled from aqueducts and artesian wells in Italy. Experimental parameters, such as sample volume, stirring, salting out, extraction temperature, and extraction time, were evaluated and optimized. The LODs ranged from 1 to 10 ng/L and LOQs from 5 to 50 ng/L. A linear response was confirmed by correlation coefficients ranging from 0.9443 to 0.9999. Quantifiable organohalogen residues were found in 11 water samples, with concentration up to 11.3 ± 0.5 μg/L for the sum of all trihalomethanes and 0.66 ± 0.03 μg/L for the sum of trichloroethylene and tetrachloroethylene. These concentrations are lower than the current regulatory limits in Italy.
Extension of the Validation of AOAC Official MethodSM 2005.06 for dc-GTX2,3: Interlaboratory Study
Authors: Ben-Gigirey Begoña , Rodríguez-Velasco María L , Gago-Martínez Ana
Published: February 2012

AOAC Official MethodSM 2005.06 for the determination of saxitoxin (STX)-group toxins in shellfish by LC with fluorescence detection with precolumn oxidation was previously validated and adopted First Action following a collaborative study. However, the method was not validated for all key STX-group toxins, and procedures to quantify some of them were not provided. With more STX-group toxin standards commercially available and modifications to procedures, it was possible to overcome some of these difficulties. The European Union Reference Laboratory for Marine Biotoxins conducted an interlaboratory exercise to extend AOAC Official Method 2005.06 validation for dc-GTX2,3 and to compile precision data for several STX-group toxins. This paper reports the study design and the results obtained. The performance characteristics for dc-GTX2,3 (intralaboratory and interlaboratory precision, recovery, and theoretical quantification limit) were evaluated. The mean recoveries obtained for dc-GTX2,3 were, in general, low (53.1–58.6%). The RSD for reproducibility (RSDr%) for dc-GTX2,3 in all samples ranged from 28.2 to 45.7%, and HorRat values ranged from 1.5 to 2.8. The article also describes a hydrolysis protocol to convert GTX6 to NEO, which has been proven to be useful for the quantification of GTX6 while the GTX6 standard is not available. The performance of the participant laboratories in the application of this method was compared with that obtained from the original collaborative study of the method. Intralaboratory and interlaboratory precision data for several STX-group toxins, including dc-NEO and GTX6, are reported here. This study can be useful for those laboratories determining STX-group toxins to fully implement AOAC Official Method 2005.06 for official paralytic shellfish poisoning control. However the overall quantitative performance obtained with the method was poor for certain toxins.
Interlaboratory Comparison of an Analytical Method for the Determination of Semduramicin in Poultry Feed at the Authorized Level Using High-Performance Liquid Chromatography Coupled to Postcolumn Derivatization and Spectrophotometric Detection
Authors: de la Huebra María José González , Vincent Ursula , Serano Federica , von Holst Christoph
Published: February 2012

The performance characteristics of a method based on HPLC with postcolumn derivatization and spectrophotometric detection for the quantification of semduramicin in poultry feedingstuffs have been determined via a collaborative study. Semduramicin is a feed additive that is authorized for fattening chickens within the European Union at a minimum and maximum content of 20 and 25 mg/kg in feedingstuffs, respectively. The target concentration of semduramicin in the test samples ranged from 11.5 to 45.0 mg/kg. The study has been conducted with two different types of test material, namely, feedingstuff samples that have been previously ground in our laboratory and pelleted feedingstuffs. In the latter case, the laboratories participating in the study had to grind the samples prior to analysis. The obtained RSD for repeatability (RSDr) ranged from 2 to 10% for the ground materials, and from 2 and 7% for the pelleted materials. The RSD for reproducibility (RSDR) varied between 11 and 16% for the ground materials, and between 12 and 15% for the pelleted materials. These data indicated that grinding as an additional step in the analytical procedure did not influence the precision profile of the method. In addition, the HorRat values for all test materials were below or equal to 1.5, thus demonstrating that the obtained precision data were acceptable for the purpose of the method. Furthermore, an estimation of trueness based on statistical treatment of the results reported from the laboratories for spiked samples revealed acceptable mean recovery values of 88 ± 4%. Based on the obtained performance profile, the method can be considered fully validated and transferable to control laboratories to be used within the framework of official control.
Developing a Modified Preservative Efficacy Testing Approach as a Predictive Tool for the Evaluation of Preservative Systems in Liquid Home Care Products Under Variable Test Conditions
Authors: Hoyt Anne L , Bushman Don , Lewis Nathan , Faber Robert
Published: February 2012

How can a formulator have confidence that a preservative system will perform as expected under adverse conditions? Extreme conditions that can lead to the development of “off odors” in the product can be a serious challenge for companies providing home care products in the global market. Formulation and stability testing occur under controlled parameters that simulate limited environmental conditions and microbial challenges are typically performed with a standard inoculum level. While this is an acceptable and dependable process, it does not necessarily assess how well a preservative system can perform under extreme environmental conditions or against unusually high levels of bacterial challenges. This is especially true when formulations are diluted and stored by the end-user. By modifying microbial challenge testing of a liquid dishwashing product to include unexpected dilution schemes, increased microbial assaults, and elevated temperatures, a pattern of preservative efficacy was established. The resulting approach proved to be a useful tool when developing use directions, recommended dilution levels, the overall surfactant system, preservative type, and storage restrictions.
BIOTECON Diagnostics foodproof®Listeria monocytogenes Detection Kit, 5′ Nuclease in Combination with the foodproof ShortPrep II Kit
Authors: Junge Benjamin , Grönewald Cordt , Berghof-Jäger Kornelia
Published: February 2012

A method was developed for the detection of Listeria monocytogenes in food. The method is based on real-time PCR using hydrolysis probes (5′ Nuclease). This advanced PCR method was designed to reduce the time necessary to achieve results from PCR reactions and to enable the user to monitor the amplification of the PCR product simultaneously, in real-time. After DNA isolation using the BIOTECON food proof® ShortPrep II Kit designed for the rapid preparation of L. monocytogenes DNA for direct use in PCR, the real- time detection of L. monocytogenes DNA is carried out using the food proof Listeria monocytogenes Detection Kit. The kit provides primers and hydrolysis probes for sequence-specific detection, convenient premixed reagents, and controls for reliable interpretation of results. For the internal comparison study, three different foods (soft cheese, coalfish, and smoked ham) were analyzed, chosen from the 15 food groups recommended by the AOAC Research Institute for detection of L. monocytogenes. From each food, 20 samples were inoculated with a low level (1–10 CFU/25 g) and 20 samples with a high level (10–50 CFU/25 g) of L. monocytogenes. Additionally, five nonspiked samples were prepared from each food. Depending on the matrix, the food samples were examined with the test kits and compared with the cultural methods according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual or the U.S. Department of Agriculture/Food Safety and Inspection Service Microbiology Laboratory Guidebook.
Development and Validation of Rapid Ion-Pair RPLC Method for Simultaneous Determination of Certain B-Complex Vitamins Along with Vitamin C
Authors: Patil Suyog S , Srivastava Ashwini K
Published: February 2012

A rapid, simple, and accurate ion-pair RPLC method has been developed for simultaneous analysis of vitamin C and major B-complex vitamins. An RP C18 column thermostated at 30°C was used with gradient elution of mobile phase comprising 10 mM potassium dihydrogen phosphate buffer (containing 3 mM sodium hexane-1-sulfonate, adjusted to pH 2.80 with o-phosphoric acid) and methanol at a flow rate of 1.0 mL/min to achieve the best possible separation and resolution of all vitamins in about 11.00 min. The detection was performed at 274 nm. The method has been implemented successfully for simultaneous determination of vitamins present in 12 multivitamin/multimineral pharmaceutical preparations, as well as in human urine. Typical validation characteristics were evaluated in accordance with International Conference on Harmonization guidelines. Good linearity over the investigated concentration levels was observed. Intraday repeatability was ≤2.0%, and interday variation was ≤2.6%, for all vitamins. The method can be used for assay of these vitamins over a wide concentration range with good precision and accuracy; hence, it would be appropriate for routine QC as well as in clinical analysis.
Variances and Uncertainties of the Sample Laboratory-to-Laboratory Variance (sL2) and Standard Deviation (sL) Associated with an Interlaboratory Study
Authors: McClure Foster D , Lee Jung K
Published: February 2012

The validation process for an analytical methodusually employs an interlaboratory study conducted as a balanced completely randomized model involving a specified number of randomly chosen laboratories, each analyzing a specified number of randomly allocated replicates. For such studies, formulas to obtain approximate unbiased estimates of the variance and uncertainty of the sample laboratory-to-laboratory (lab-to-lab) STD (sL) have been developed primarily to account for the uncertainty of sL when there is a need to develop an uncertainty budget that includes the uncertainty of sL. For the sake of completeness on this topic, formulas to estimate the variance and uncertainty of the sample lab-to-lab variance (sL2) were also developed. In some cases, it was necessary to derive the formulas based on an approximate distribution for sL2.
Validation of a New Enzyme-Linked Immunosorbent Assay to Detect the Triggering Proteins and Peptides for Celiac Disease: Interlaboratory Study
Authors: Mujico Jorge R , Dekking Liesbeth , Kooy-Winkelaar Yvonne , Verheijen Ron , Wichen Piet van , Streppel Lucia , Sajic Nermin , Drijfhout Jan W , Koning Frits
Published: February 2012

The performance of Gluten-Tec® (EuroProxima, Arnhem, The Netherlands) was tested through an interlaboratory study in accordance with AOAC guidelines. Gluten-Tec is a competitive ELISA that detects an immunostimulatory epitope of α-gliadin in dietary food for celiacs. Fifteen laboratories, representing 14 different countries, announced their interest in taking part in this study. Of the 12 laboratories that sent the results within the established timeframe, two submitted inappropriate standard curves and were excluded from the statistical analysis. Four different food matrixes (rice-based baby food, maize bread, chocolate cake mix, and beer) were selected for preparing the test samples. Two gliadin extraction procedures were used: the conventional 60% ethanol, and a new method based on the reducing reagent dithiothreitol. The 38 samples (19 blind duplicates) tested in this study were prepared by diluting the different extracts in order to cover a wide range of gliadin levels. Both sample extraction and dilution were performed by EuroProxima; the present interlaboratory study was focused only on testing the ELISA part of the Gluten-Tec kit protocol. Repeatability values (within-laboratory variance), expressed as RSDr, ranged from 6.2 to 25.7%, while reproducibility values (interlaboratory variance), expressed as RSDR, ranged from 10.6 to 45.9%. Both statistical parameters were in the acceptable range of ELISAs under these conditions, and the method will be presented to the Codex Alimentarius as a preferred method for gluten analysis.
Detection of Hazelnut in Foods Using ELISA: Challenges Related to the Detectability in Processed Foodstuffs
Authors: Cucu Tatiana , Devreese Bart , Trashin Stanislav , Kerkaert Barbara , Rogge Maarten , De Meulenaer Bruno
Published: February 2012

Hazelnuts are widely used nowadays, and can pose a serious threat to allergic consumers due to cross-contamination that may occur during processing. This might lead to the presence of hidden hazelnut in foods. Therefore, reliable tests are needed to detect hazelnut, especially in processed foods. A hazelnut-specific indirect competitive ELISA based on polyclonal chicken antibodies was developed. The polyclonal antibodies were raised against modified hazelnut proteins in order to improve the detectability of hazelnut proteins in processed foods. The assay showed a detection limit of 1.36 μg hazelnut protein/mL of 5 mM urea in phosphate-buffered saline buffer (pH 7.4). Limited cross-reactivity with walnut and pecan nut was observed; no cross-reactivity was observed with other food ingredients. Blank cookies spiked before analysis showed recoveries of 73–107%. However, cookies spiked before baking showed that the detectability was severely decreased. Addition of lactose to the cookies, which led to more severe modification through the Maillard reaction, led to an increase in the detectability. These results indicate that using antibodies developed toward allergens modified through food processing-simulating reactions is a better approach for detection.
Validation of the Delvotest SP NT DA
Authors: Hennart Stephen L A , Faragher John
Published: February 2012

Delvotest® SP NT DA is designed to test milk for the presence of antibacterial substances, such as antibiotics. The test is made of an agar gel containing bacterial spores and a color indicator. The milk sample is added onto the agar gel, and the test is incubated at 64°C. The principle of the test is based on the diffusion of possible inhibitory substances that may be present in the milk sample into agar. This reduces growth and acid production by the test organism, and delays or prevents the agar from changing color from purple to yellow. The Delvotest Accelerator is an automated system in which the plates containing the milk to be analyzed are placed for incubation. The Accelerator automatically detects the end of the incubation and reads the results. A sample containing antibiotic will be noted as “positive.” A sample without antibiotics or with antibiotics at concentrations below detection level will be noted as “negative.” The present report includes all technical details about the Delvotest SP NT DA, and the results of the validation study. The validation study demonstrates that the Delvotest SP NT DA conforms to the product performance claims and confirms the robustness of the test. The Delvotest SP NT DA is, therefore, granted Performance Tested MethodSM certification.
Quantitative HPLC Method for Determining Two of the Major Active Phthalides from Ligusticum porteri Roots
Authors: Rivero Isabel , Juárez Krutzkaya , Zuluaga Magda , Bye Robert , Mata Rachel
Published: February 2012

Z-Ligustilide (1) and Z-6,6′,7,3′-α-diligustilide (2), two of the major active phthalides of the medicinal plant Ligusticum porteri (osha), were chosen for the development and validation of an HPLC–diode array detection method suitable for QC of the crude drug. The method used gradient elution to achieve separation on a Hibar RT LiChrospher® 100 C18 column. The LOD values were 29 and 45 μg/mL, and the LOQs were 89 and 125 μg/mL, respectively. The method showed good intraday precision (%RSD: 0.7 for 1 and 3.1 for 2) and interday precision (%RSD: 1.2 for 1 and 1.8 for 2). The method was used for the analysis of 1 and 2 in crude drug samples and several herbal preparations from Mexico and the United States. Quantitative analysis showed that the content of the two phthalides varied significantly among the samples. All the samples contained higher concentrations of 1 (0.15–2.5%) than 2 (0.002–1.0%). The profiles of volatile compounds in the essential oil obtained by hydrodistillation and solid-phase microextraction of L. porteri roots were analyzed by GC-MS. Thirty one chemical constituents (>99.7% of the total content) were identified in the essential oil, which was characterized by the presence of a high percentage of phthalides (44.61%) and sesquiterpenes (10.69%). The major light volatile components extracted by solid-phase microextraction were monoterpenes.
Composition of Pomegranate Juice
Authors: Krueger Dana A
Published: February 2012

A database of 793 commercial pomegranate juices was analyzed to produce a profile for authentication of pure pomegranate juice. The database consisted of data from a mix of authentic and adulterated samples. Statistical tools were used to reduce the database to a stable sample set of 477 presumably authentic samples. The profile obtained (mean, SD at 16 Brix) are as follows: fructose (g/100 g) 6.83, 0.50; glucose (g/100 g) 6.66, 0.44; sucrose (g/100 g) 0.00, 0.00; sorbitol (g/100 g) 0.00, 0.01; acidity (g/100 g as citric acid) 1.25, 0.32; citric acid (g/100 g) 1.19, 0.30; malic acid (g/100 g) 0.065, 0.034; tartaric acid (g/100 g) 0.00, 0.00; isocitric acid (mg/kg) 63, 21; potassium (mg/kg) 2320, 400; proline (mg/kg) 7, 5; formol value [milliequivalents/100 g] 1.00, 0.24; 13C/12C ratio [o/oo Pee Dee belemnite]–26.4, 0.8. The profile samples had a consistent anthocyanin pattern consisting of four major peaks corresponding to delphinidin-3,5-diglucoside, delphinidin-3-glucoside, cyanidin-3,5-diglucoside, and cyanidin-3-glucoside. Minor peaks corresponding to pelargonidin-3,5-diglucoside and pelargonidin-3-glucoside were also generally present. No maltose, D-malic acid, or tartaric acid were detected in any of the samples. The profile obtained corresponds closely with previously published data.
Spectrophotometric Determination of Mercury in Water Samples After Preconcentration Using Dispersive Liquid–Liquid Microextraction
Authors: Lemos Valfredo Azevedo , Santos Liz Oliveira dos , Silva Eldevan dos Santos , Vieira Emanuel Vitor dos Santos
Published: February 2012

A simple method for the determination of mercury in water samples after preconcentration using dispersive liquid–liquid microextraction is described. The procedure is based on the extraction of mercury in the form of a complex and its subsequent determination by spectrophotometry. The complex is formed between Hg(II) and 2-(2-benzothiazolylazo)-p-cresol. The detection at 650 nm is performed directly in the metal-rich phase, which is spread on a triacetylcellulose membrane. The method eliminates the need to use a cuvet or large quantities of samples and reagents. The parameters that influence the preconcentration were studied, and the analytical characteristics were determined. The enrichment factor and the consumptive index for this method were 64 and 0.16 mL, respectively. The LOD (3.3 μg/L) and LOQ (11.1 μg/L) were also determined. The accuracy of the method was tested by the determination of mercury in certified reference materials BCR 397 (Human Hair) and SRM 2781 (Domestic Sludge). The method was applied to the determination of mercury in samples of drinking water, sea water, and river water.
Probability of Identification: A Statistical Model for the Validation of Qualitative Botanical Identification Methods
Authors: LaBudde Robert A , Harnly James
Published: February 2012

A qualitative botanical identification method (BIM) is an analytical procedure that returns a binary result (1 = Identified, 0 = Not Identified). A BIM may be used by a buyer, manufacturer, or regulator to determine whether a botanical material being tested is the same as the target (desired) material, or whether it contains excessive nontarget (undesirable) material. The report describes the development and validation of studies for a BIM based on the proportion of replicates identified, or probability of identification (POI), as the basic observed statistic. The statistical procedures proposed for data analysis follow closely those of the probability of detection, and harmonize the statistical concepts and parameters between quantitative and qualitative method validation. Use of POI statistics also harmonizes statistical concepts for botanical, microbiological, toxin, and other analyte identification methods that produce binary results. The POI statistical model provides a tool for graphical representation of response curves for qualitative methods, reporting of descriptive statistics, and application of performance requirements. Single collaborator and multicollaborative study examples are given.
Determination of Total Iodine in Foods and Dietary Supplements Using Inductively Coupled Plasma–Mass Spectrometry
Authors: Sullivan Darryl , Zywicki Richard
Published: February 2012

A method was developed and validated for the determination of total iodine in a wide variety of food products and dietary supplements. The method involves a unique sample digestion with a KOH solution in an oven or by using an open-vessel microwave system. After digestion, a stabilizer is added and the solution is taken to volume, then filtered and analyzed either directly or after dilution. The amount of iodine is determined with inductively coupled plasma–mass spectrometry (ICP-MS). The method was validated by experiments to determine its precision, accuracy, linearity, specificity, ruggedness, and robustness. The LOQ of this method is 25–50 μg/kg. The method demonstrated an average RSD of 2.27% during analysis of milk powder and 4.30% during analysis of a dietary supplement tablet reference material. The accuracy of the method as determined with these same reference materials was 100 and 94.2%, respectively. The method has been used successfully on commodity foods, processed foods, dairy products, pet food, infant formula, animal feed, mineral premixes, and a variety of dietary supplements.
Determination of Calcium, Copper, Iron, Magnesium, Manganese, Potassium, Phosphorus, Sodium, and Zinc in Fortified Food Products by Microwave Digestion and Inductively Coupled Plasma-Optical Emission Spectrometry: Single-Laboratory Validation and Ring Trial
Authors: Poitevin Eric
Published: February 2012

A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official MethodSM 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official MethodSM 984.27 for fortified food products, including infant formula.
Gut Microbiota, Diet, and Heart Disease
Authors: Wong Julia M W , Esfahani Amin , Singh Natasha , Villa Christopher R , Mirrahimi Arash , Jenkins David J A , Kendall Cyril W C
Published: February 2012

Modulation of the gut microbiota is an area of growing interest, particularly for its link to improving and maintaining the systemic health of the host. It has been suggested to have potential to reduce risk factors associated with chronic diseases, such as elevated cholesterol levels in coronary heart disease (CHD). Diets of our evolutionary ancestors were largely based on plant foods, high in dietary fiber and fermentable substrate, and our gut microbiota has evolved against a background of such diets. Therapeutic diets that mimic plant-based diets from the early phases of human evolution may result in drug-like cholesterol reductions. In contrast, typical Western diets low in dietary fiber and fermentable substrate, and high in saturated and trans fatty acids, are likely contributors to the increased need for pharmacological agents for cholesterol reduction. The gut microbiota of those consuming a Western diet are likely underutilized and depleted of metabolic fuels, resulting in a less than optimal gut microbial profile. As a result, this diet is mismatched to our archaic gut microbiota and, therefore, to our genome, which has changed relatively little since humans first appeared. While the exact mechanism by which the gut microbiota may modulate cholesterol levels still remains uncertain, end products of bacterial fermentation, particularly the short chain fatty acids (i.e., propionate), have been suggested as potential candidates. While more research is required to clarify the potential link between gut microbiota and CHD risk reduction, consuming a therapeutic diet rich in plant foods, dietary fiber, and fermentable substrate would be a useful strategy for improving systemic health, possibly by altering the gut microbiota.
Characterization of paper mill effluent using indicators and source tracking methods
Authors: Long Sharon C. , Stietz Jamie R. , Olstadt Jeremy , Hedman Curtis J. , Plummer Jeanine D.
Published: February 2012

Monitoring of indicator organisms is conducted to assess potential risk of pathogen exposure from freshwaters such as recreational waters and drinking water sources. Total coliforms, fecal coliforms, Escherichia coli and enterococci are the most commonly measured indicator organisms. Their presence can indicate the potential presence of fecally transmitted pathogens. In Wisconsin, E. coli are used for determining potential human health risk in recreational waters. However, it has been shown that E. coli can survive and reproduce in a variety of aquatic environments, including in the activated sludge process of paper mills. Previous monitoring in a river in Wisconsin receiving paper mill effluent indicated that the mill was contributing to elevated E. coli levels that could affect the number of closings at a public beach located downstream from the mill. The goal of this study was to understand the public health implications of the E. coli at the beach. Samples were collected upstream and downstream of the paper mill's wastewater treatment plant discharge as well as within the mill processes. Samples were analyzed for indicator organisms (coliforms, E. coli, and enterococci) and microbial source tracking (MST) targets. Although indicator concentrations were typically below detection limits in the mill process water, indicators regrew in the activated sludge wastewater treatment process such that fecal coliforms and E. coli were detected in all wastewater treatment plant effluent samples. Although the paper mill effluent periodically appears to affect the E. coli levels at the downstream beach, MST results demonstrate that E. coli from the mill is not of human fecal origin, and therefore not likely a cause for health concerns.
Inactivation of Naegleria Fowleri by chlorine and ultraviolet light
Authors: Sarkar Payal , Gerba Charles P.
Published: February 2012

Naegleria fowleri is a free‐living protozoan that causes the fatal disease primary amoebic meningoencephalitis. The only cases associated with drinking water have occurred in Australia and Arizona. One study found N. fowleri in 8% (n = 143) of all municipal untreated drinking water wells tested. The C × T values (concentration × contact time) for chlorine inactivation of N. fowleri trophozoites and cysts at an average disinfectant concentration of 1 mg/L were determined using the efficiency factor Hom kinetic model. The estimated C × T values for N. fowleri cysts are comparable to the published values for Giardia lamblia cysts, but are lower than those for Cryptosporidium parvum oocysts. In this study, the ultraviolet light dosage required to inactivate the cyst stage of N. fowleri was determined to be greater than that of Cryptosporidium oocysts but less than that of Acanthamoeba cysts.
Antifoaming Agents
Authors: Hilberer Alain , Chao Sung‐Hsuen
Published: February 2012

A review is presented of the materials used to control or eliminate foam in industrial processes and how these materials function. These materials are classified by their chemical type. The main active liquid‐phase components are hydrocarbon oils, polyethers, and silicone fluids; the main solid‐phase components are waxy hydrocarbons and hydrophobic silica. Formulating the antifoam active into a suitable delivery system is essential to ensure optimal performance in terms of activity, physical and chemical stability, cost, ease of use and for preventing negative side, and downstream effects. Examples of formulations for antifoams delivery in dispersions, emulsions, or powders are described. The mechanisms of foaming and defoaming are outlined with an emphasis on surface behavior such as entering, spreading, bridging, stretching, and dewetting phenomena. The importance of entry barrier on the rapidity of antifoaming action, the role of dispersed hydrophobic solids, and the mechanism of antifoam deactivation are highlighted. Applications in various areas are briefly reviewed, including pulp and paper, fermentation, paints, coatings and inks, oil and petrochemicals, cleaning compounds, wastewater treatment, metal working, polymerization, construction, textiles, fertilizers, food and beverages, leather, adhesives and sealants, chemical processing, and, medical and pharmaceuticals. Economic and health and safety factors are considered. Test methods, such as pneumatic, dynamic, shaking, pouring, stirring, and blending methods, are also briefly reviewed.
Metal‐Free Growth of Nanographene on Silicon Oxides for Transparent Conducting Applications
Authors: Medina Henry , Lin Yung‐Chang , Jin Chuanhong , Lu Chun‐Chieh , Yeh Chao‐Hui , Huang Kun‐Ping , Suenaga Kazu , Robertson John , Chiu Po‐Wen
Published: February 2012

Conventional methods to prepare large‐area graphene for transparent conducting electrodes involve the wet etching of the metal catalyst and the transfer of the graphene film, which can degrade the film through the creation of wrinkles, cracks, or tears. The resulting films may also be obscured by residual metal impurities and polymer contaminants. Here, it is shown that direct growth of large‐area flat nanographene films on silica can be achieved at low temperature (400 °C) by chemical vapor deposition without the use of metal catalysts. Raman spectroscopy and TEM confirm the formation of a hexagonal atomic network of sp2‐bonded carbon with a domain size of about 3–5 nm. Further spectroscopic analysis reveals the formation of SiC between the nanographene and SiO2, indicating that SiC acts as a catalyst. The optical transmittance of the graphene films is comparable with transferred CVD graphene grown on Cu foils. Despite the fact that the electrical conductivity is an order of magnitude lower than CVD graphene grown on metals, the sheet resistance remains 1–2 orders of magnitude better than well‐reduced graphene oxides.
Ultrasensitive, Biocompatible, Quantum‐Dot‐Embedded Silica Nanoparticles for Bioimaging
Authors: Jun Bong‐Hyun , Hwang Do Won , Jung Heung Su , Jang Jaeho , Kim Hyunsoo , Kang Homan , Kang Taegyu , Kyeong San , Lee Hyeokjae , Jeong Dae Hong , Kang Keon Wook , Youn Hyewon , Lee Dong Soo , Lee Yoon‐Sik
Published: February 2012

The successful development of highly sensitive, water‐compatible, nontoxic nanoprobes has allowed nanomaterials to be widely employed in various applications. The applicability of highly bright quantum dot (QD)‐based probes consisting of QDs on 120 nm silica nanoparticles (NPs) with silica shells is investigated. Their substantial merits, such as their brightness and biocompatibility, for effective bioimaging are demonstrated. Silica‐coated, QD‐embedded silica NPs (Si@QDs@Si NPs) containing QDs composed of CdSe@ZnS (core‐shell) are prepared to compare their structure‐based advantages over single QDs that have a similar quantum yield (QY). These Si@QDs@Si NPs exhibit approximately 200‐times stronger photoluminescence (PL) than single QDs. Cytotoxicity studies reveal that the Si@QDs@Si NPs are less toxic than equivalent numbers of silica‐free single quantum dots. The excellence of the Si@QDs@Si NPs with regard to in vivo applications is illustrated by significantly enhanced fluorescence signals from Si@QDs@Si‐NP‐tagged cells implanted in mice. Notably, a more advanced version of QD‐based silica NPs (Si@mQDs@Si NPs), containing multishell quantum dots (mQDs) composed of CdSe@CdS@ZnS, are prepared without significant loss of QY during surface modification. In addition, the Si@mQDs@Si NPs display a fivefold higher fluorescence activity than the Si@QDs@Si NPs. As few as 400 units of Si@mQDs@Si‐ NP‐internalized cells can be detected in the cell‐implanted mouse model.
Effect of Elastic Network of Ceramic Fillers on Thermal Cycle Stability of a Solid Oxide Fuel Cell Stack
Authors: Lee Jong‐Ho , Kim Hyoungchul , Kim Sung Moon , Noh Tae‐Wook , Jung Hwa‐Young , Lim Hyun‐Yup , Jung Hun‐Gi , Son Ji‐Won , Kim Hae‐Ryoung , Kim Byung‐Kook , Je Hae‐June , Lee Jae‐Chun , Song Huesup , Lee Hae‐Weon
Published: February 2012

Glass‐based seals for planar solid‐oxide fuel‐cell (SOFC) stacks are open to uncontrolled deformation and mechanical damages, limiting both sealing integrity and stack reliability, particularly in thermal cycle operations. If the glass‐based seals work like an elastomer‐based compressive seal, SOFC stacks may survive unprecedented numbers of thermal cycles. A novel composite sealing gasket is successfully developed to mimic the unique features of the elastomer‐based compressive seal by controlling the composition and packing behavior of binary ceramic fillers. A single‐cell SOFC stack undergoes more than 100 thermal cycles with little performance loss, during which the sealing integrity is lost/recovered repeatedly upon cooling and reheating, corresponding to unloading/loading of the elastomer‐based compressive seal. The thermal‐cycle responses of the SOFC stack are explained in sequence by the concurrent events of elastic deformation/recovery of ceramic filler network and corresponding redistribution of sealing glass.
Association between copy number variants in 16p11.2 and major depressive disorder in a German case–control sample
Authors: Degenhardt Franziska , Priebe Lutz , Herms Stefan , Mattheisen Manuel , Mühleisen Thomas W. , Meier Sandra , Moebus Susanne , Strohmaier Jana , Groß Magdalena , Breuer René , Lange Christoph , Hoffmann Per , Meyer‐Lindenberg Andreas , Heinz Andreas , Walter Henrik , Lucae Susanne , Wolf Christiane , Müller‐Myhsok Bertram , Holsboer Florian , Maier Wolfgang , Rietschel Marcella , Nöthen Markus M. , Cichon Sven
Published: February 2012

The majority of genetic risk factors for major depressive disorder (MDD) still await identification. Since copy number variants (CNVs) have been implicated in various neuropsychiatric disorders, the question arises as to whether CNVs also play a role in MDD. We performed a genome‐wide CNV study using Illumina's SNP array data from 604 MDD patients and 1,643 controls. Putative CNVs were detected with the CNV algorithms QuantiSNP and PennCNV. CNVs with ≥30 consecutive SNPs and a log Bayes Factor/confidence value of ≥30 were statistically analyzed using PLINK. Further analyses and technical verification were only performed in the case of regions for which CNV calls from both programs showed nominal significance. Set‐based tests were used to test whether common variants in the CNV regions showed association in two GWAS datasets of MDD. CNVs from four chromosomal regions were associated with MDD. The following were more frequent in patients than controls: microdeletions in 7p21.3 (P = 0.033) and 18p11.32 (P = 0.030); microduplications in 15q26.3 (P = 0.033); and the combination of microdeletion/duplications in 16p11.2 (P ≤ 0.018). SNPs in CNV region 16p11.2 showed significant association in a set‐based test (P = 0.026). Microdeletions/duplications in 16p11.2 are the most promising CNVs, since these affect genes and CNVs in this region have been implicated in other neuropsychiatric disorders. The association finding for common SNPs provides further support for the hypothesis that this region is involved in the development of MDD. © 2012 Wiley Periodicals, Inc.
Niedermolekulare organische Halbleiter auf dem Vormarsch – Ausblick auf künftige Solartechniken
Authors: Mishra Amaresh , Bäuerle Peter
Published: February 2012

Wir bieten hier aus der Sicht von Organikern einen aktuellen Überblick über organische Solarzellen, deren Absorberschicht auf niedermolekularen Molekülen oder Oligomeren basiert, und behandeln im Detail Planar‐Heteroübergangs‐ sowie Bulk‐Heteroübergangs‐Solarzellen mit organischen Donor‐ (p‐Halbleiter) und Akzeptormaterialien (n‐Halbleiter). Dabei liegt das Hauptaugenmerk auf dem Design und der Entwicklung von molekularen Materialien und auf deren Leistung in entsprechenden Solarzellen. In den vergangenen Jahren wurde in großem Umfang akademische und industrielle Forschung in Richtung organischer Solarzellen betrieben. Kurz vor der geplanten Kommerzialisierung von organischen Solarzellen liefern wir hier einen Überblick über Effizienzen, die bisher in solchen Solarzellen erzielt wurden, und präsentieren Materialien und Solarzellenkonzepte, die in den letzten zehn Jahren entwickelt wurden. Darüber hinaus werden Ansätze zur Erhöhung der Effizienz von organischen Solarzellen analysiert.
Small Molecule Organic Semiconductors on the Move: Promises for Future Solar Energy Technology
Authors: Mishra Amaresh , Bäuerle Peter
Published: February 2012

This article is written from an organic chemist’s point of view and provides an up‐to‐date review about organic solar cells based on small molecules or oligomers as absorbers and in detail deals with devices that incorporate planar‐heterojunctions (PHJ) and bulk heterojunctions (BHJ) between a donor (p‐type semiconductor) and an acceptor (n‐type semiconductor) material. The article pays particular attention to the design and development of molecular materials and their performance in corresponding devices. In recent years, a substantial amount of both, academic and industrial research, has been directed towards organic solar cells, in an effort to develop new materials and to improve their tunability, processability, power conversion efficiency, and stability. On the eve of commercialization of organic solar cells, this review provides an overview over efficiencies attained with small molecules/oligomers in OSCs and reflects materials and device concepts developed over the last decade. Approaches to enhancing the efficiency of organic solar cells are analyzed.
Mechanical properties of functionally graded carbon black–styrene butadiene rubber composites: Effect of modifying gradation and average filler loading
Authors: Ahankari Sandeep , Kar Kamal K.
Published: February 2012

The mechanical properties of functionally graded polymeric composites (FGPCs) with varying carbon black loading and the effect of stacking sequence in styrene butadiene rubber (SBR) matrix were studied. For a given average amount of nanofiller, the modulus of FGPCs for any given stacking sequence of layers is higher when compared with its uniformly dispersed polymeric composites (UDPCs) counterpart. Tensile strength, elongation at break, and tear strength either increase or decrease depending on the stacking sequence and average loading of the filler in FGPCs. In addition, the smoother gradation (i.e., lesser difference in the amounts of CB content in adjacent layers) and a wide gap of difference in CB content in a stack has a profound effect on the modulus and tensile strength of FGPCs. Dynamic mechanical analysis shows lesser damping in FGPCs than UDPCs. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The Pulmonary Anatomy of Alligator mississippiensis and Its Similarity to the Avian Respiratory System
Authors: Sanders R. Kent , Farmer C.G.
Published: February 2012

Using gross dissections and computed tomography we studied the lungs of juvenile American alligators (Alligator mississippiensis). Our findings indicate that both the external and internal morphology of the lungs is strikingly similar to the embryonic avian respiratory system (lungs + air sacs). We identified bronchi that we propose are homologous to the avian ventrobronchi (entobronchi), laterobronchi, dorsobronchi (ectobronchi), as well as regions of the lung hypothesized to be homologous to the cervical, interclavicular, anterior thoracic, posterior thoracic, and abdominal air sacs. Furthermore, we suggest that many of the features that alligators and birds share are homologous and that some of these features are important to the aerodynamic valve mechanism and are likely plesiomorphic for Archosauria. Anat Rec, 2012. © 2012 Wiley Periodicals Inc.
Distribution Change of Mast Cells in Human Nasal Polyps
Authors: Zhang Guimin , Shao Jie , Su Chao , Zhao Xiulan , Wang Xinting , Sun Xiaoming , Shi Wenjie , Sun Peiyong , Yao Zhi , Yang Jie
Published: February 2012

Recent studies have shown that mast cells are involved in pathophysiologic processes of chronic inflammation. However, little is known about the distribution of mast cells in nasal polyps, which is a chronic inflammatory disease of the upper airways. Biopsy specimens from patients with nasal polyps (n = 20) and control patients without nasal polyps (n = 8) were included in this study. The distribution of mast cells in nasal polyps was determined by immunohistochemistry. Meanwhile, we detected the expression of chemokines (CCL5, CCL11, CX3CL1, IL‐8, IL‐6) in the epithelial cells of normal nasal mucosa and nasal polyps. In addition, the expression of these chemokines was investigated by western bolting in airway epithelial cells line (A549 cells) under inflammatory condition. Mast cells migrated toward intraepithelium in nasal polyps and the expression of chemokines (CCL5, CCL11, CX3CL1, IL‐8) was up‐regulated in the epithelial cells of nasal polyps compared with normal nasal mucosa. The expression of chemokines was also up‐regulated in A549 cells after Lipopolysaccharide (LPS)‐treatment for 3 hr and 6 hr. Our findings showed that mast cells migrate toward intraepithelium in nasal polyps and the overexpression of chemokines (CCL5, CCL11, CX3CL1, IL‐8) suggested that they might be responsible for mast cells migration. It implies that mast cell play potential roles in the development of nasal polyps. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Pharmacokinetics and metabolism of jatrorrhizine, a gastric prokinetic drug candidate
Authors: Shi Rong , Zhou Hui , Ma Bingliang , Ma Yueming , Wu Dazheng , Wang Xinhong , Luo Hongfeng , Cheng Nengneng
Published: February 2012

Jatrorrhizine, a protoberberine alkaloid derived from Coptis chinensis, is currently under investigation as a natural gastric prokinetic drug candidate. In vitro and in vivo studies were conducted to characterize its pharmacokinetics and metabolism. After intravenous administration, the plasma concentration kinetics and major metabolites in rats were investigated. The metabolic kinetics, key cytochrome P450 enzymes and UDP‐glucuronosyltransferase isoforms (UGTs) of jatrorrhizine were studied in rat liver microsomes (RLMs). After intravenous administration, plasma jatrorrhizine concentrations showed a biphasic decline, dose‐independent clearance and half‐life of terminal elimination phase, and a relatively large distribution volume. The metabolic pathway for the conversion of jatrorrhizine was important for its elimination. In addition, the demethylated and glucuronidated products were found to be the major metabolites in rats. The enzyme kinetics for both demethylation and glucuronidation were fitted to the hyperbolic Michaelis‐Menten equation in RLMs. CYP3A1/2 and CYP2D2 were mainly responsible for demethylation, and UGT 1A1 and 1A3 were responsible for glucuronidation in RLMs. The metabolic properties of jatrorrhizine suggest multiple metabolic pathways. These results will contribute to promote further research and development of jatrorrhizine. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis of Dibenzothiophene‐Containing Ladder Polysilsesquioxane as a Blue Phosphorescent Host Material
Authors: Ren Zhongjie , Sun Dianming , Li Huihui , Fu Qiang , Ma Dongge , Zhang Jianming , Yan Shouke
Published: February 2012

A ladder polysilsesquioxanes with side chain of dibenzothiophene groups (BS‐LPSQ) was successfully synthesized. The ladder structure of BS‐LPSQ was characterized by MALDI‐TOF MS, XRD, and 1H NMR spectroscopy. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and spectroscopic analyses revealed that the BS‐LPSQ has good film‐forming ability, high thermal and morphological stability, and good miscibility to the dopant iridium bis(4,6‐difluorophenyl)pyridinato‐N,C2‐picolinate (FIrpic), high triplet energy, and a wide bandgap. In addition, compared with the ringed polysiloxane BS‐PSQ phosphorescent host material reported previously, the ladder structure of BS‐LPSQ has not only a higher thermal resistance, but also could prevent molecular aggregation and effectively avoid quenching of fluorescence. Thus, the BS‐LPSQ may be used as a better host for the blue‐light‐emitting iridium complex FIrpic. The performance of the electrophosphorescent device, based on the ladder BS‐LPSQ as the active layer, is superior to that of ringed BS‐PSQ and any other polyhedral oligomeric silsesquioxane (POSS)‐based or polymer host materials.
Solution‐phase synthesis and evaluation of tetraproline chiral stationary phases
Authors: Dai Zhi , Ye Guozhong , Pittman Charles U. , Li Tingyu
Published: February 2012

A protocol was developed for the solution‐phase synthesis of multigram amounts of two 9‐fluorenylmethoxycarbonyl (Fmoc)‐protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution‐phase‐synthesized tetraproline CSPs with that prepared by stepwise solid‐phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution‐phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid‐phase synthesis of oligoproline CSPs. Chirality, 2012. © 2012 Wiley Periodicals, Inc.