Thiosulphate In Gelatin Determination By Extraction And Polarography

A proportion of the thiosulphate in gelatin may be bound to the gelatin by cations so that all thiosulphate is not removed by aqueous extraction. After exchange of cations for sodium, a quantitative extraction of thiosulphate can be obtained. This conclusion rests on the following evidence:

(1) all thiosulphate added to deionized gelatin was extracted;

(2) exchange of cations in gelatin for sodium increased the yield of thiosulphate on extraction by an amount that varied between different gelatin samples;

(3) when anions (including thiosulphate) in gelatin were exchanged for chloride, a proportion of any further thiosulphate added remained bound to the gelatin apparently by the residual cations.

It was found that 200 p.p.m. of aluminium ion added to deionized gelatins reduced the fraction of added thiosulphate that could be extracted.

The amount of tetrathionate found was considerably less than the amount of thiosulphate and appears to have been formed during the extraction procedure.     

Multi-technique comparison of immobilized and hybridized oligonucleotide surface density on commercial amine-reactive microarray slides

To establish a quantitative, corroborative understanding of observed correlations between immobilized probe DNA density on microarray surfaces and target hybridization efficiency in biological samples, we have characterized amine-terminated, single-stranded DNA probes attached to amine-reactive commercial microarray slides and complementary DNA target hybridization using fluorescence imaging, X-ray photoelectron spectroscopy (XPS) and 32P-radiometric assays. Importantly, we have reproduced DNA probe microarray immobilization densities in macroscopic spotted dimensions using high ionic strength, high-concentration DNA probe solutions to permit direct XPS surface analysis of DNA surface chemistry with good reliability and reproducibility. Target capture hybridization efficiency with complementary DNA exhibited an optimum value at intermediate DNA probe immobilization densities. The macroscopic array model provides a new platform for the study of DNA surface chemistry using highly sensitive, quantitative surface analytical techniques (e.g., XPS, ToF-SIMS). Sensitive 32P-DNA radiometric density measurements were calibrated with more routine XPS DNA signals, facilitating future routine DNA density determinations without the use of a hazardous radioactive assay. The objective is to provide new insight into different surface chemistry influences on immobilized DNA probe environments that affect target capture efficiency from solution to improve microarray assay performance.     

Masked partial-word priming in visual word recognition: Effects of positional letter frequency.

In 4 primed lexical decision experiments, it was found that the positional frequencies of letters shared by the prime and target relative to the overall positional letter frequency of the target determined the magnitude of priming effects. The lower the positional frequency of shared letters, the stronger the facilitatory effect observed. Both an interactive and noninteractive semistochastic version of the interactive activation model captured the principal trends in the data. It is argued that masked partial-word priming arises from a trade-off between the facilitation generated by prime–target letter overlap and the inhibition generated from all lexical representations activated by letters in the prime that receive further support on target presentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Barriers to advancing nanotechnology to better improve and translate nanomedicines

Engineered nanomaterials and nanotechnologies promise many benefits to enhance both in vitro and in vivo performance. This is now manifest in the increasing number of reported biomedical products under development and testing that contain nanotechnologies as their distinguishing performance—enhancing components. In many cases, nano-sized materials are selected to provide a specific functional aspect that contributes to improved medical performance, either in vitro or in vivo. Nanoparticles are most commonly exploited in diverse roles in topical lotions and creams, solubilization aids, for in vitro and in vivo diagnostic and targeting agents in nanomedicines and theranostics. Despite fundamental scientific excitement and many claims to nanotechnology-based improvements in new biomedical applications, several fundamental and long-standing challenges remain to be addressed using nanomedicines to make clinically important progress. This review addresses several issues that must be fairly and objectively reported and then overcome to provide truly credible performance for nanomedicines.     

A comparative study on the use of black box modelling for piezoelectric actuators

In this article, different approaches of the use of black box modelling techniques for piezoelectric actuators are particularly addressed, regardless of the employed technique/algorithm. A modelling approach in this paper refers to two matters: the first, the role of black box techniques in modelling (i.e. if physics-based techniques are also involved in modelling; if so, how and to what extent). From this aspect, the spectrum of approaches ranges from those merged with/inspired by classical phenomenological models to an approach based on purely system identification-based techniques. The second aspect of modelling approaches, in this article, is the input variables to the model. Current and previous values of input voltage, previous values of the output (displacement), derivatives and extremum values of the system's input/output have been used as the inputs to the model so far. Both aforementioned aspects of modelling approaches are addressed appropriately in this article, and various modelling approaches in the literature are categorized and presented in a uniform and comparable manner, so that readers can easily identify research trends in this area and the gaps in the literature. One of the identified unanswered questions in the literature is whether the extremum values of the system's input/output should/should not be used as an input to black box models of piezoelectric actuators. There are works in the literature which have/have not used the aforementioned input variables, but there is no published investigation to evidently answer the proposed question. This article, in the last section, answers this question by reporting and discussing an experimental study.     

POLYCYCLIC AROMATIC HYDROCARBON REFERENCE RANGE LEVELS IN THE U.S. POPULATION BY MEASUREMENT OF URINARY MONOHYDROXY METABOLITES

We developed a gas chromatography/isotope dilution high- resolution mass spectrometry (GC/ID-HRMS) method for measuring 18 PAH metabolites representing 8 parent PAHs in 3 mL of urine at low part-per-trillion levels. We applied this method to the analysis of urine specimens from approximately 2400 people who participated in the National Health and Nutrition Examination Survey for the years 1999 and 2000 to determine levels for 14 PAH hydroxy metabolites of 7 parent compounds. Using this GC/ID-HRMS method, we found detectable concentrations for monohydroxy metabolite isomers of fluorene, phenanthrene, fluoranthene, and pyrene, and for chrysene, benzo[c]phenanthrene, and benz[a]anthracene. Some monohydroxy metabolite isomers of chrysene, benzo[c]phenanthrene, and benz[a]anthracene exhibited low detection frequencies which did not allow for geometric mean calculations. From our study, we established a reference range for the targeted PAHs in the general U.S. population.     

A parametric statistical approach to FDI for the industrial actuator benchmark

A parametric statistical approach to the industrial actuator fault-detection and isolation benchmark is presented. An algorithm for detecting a change in the dynamics of a linear system is formulated as a set of sequential probability ratio tests of the innovations from a bank of Kalman filters. The algorithm is extended to allow estimation of a disturbance using a generalised likelihood ratio test. Modifications are proposed for when the model is nonlinear and the modeling error is significant. The algorithm is evaluated using the benchmark test data and is shown to provide low detection delays while being robust to noise, disturbances and model error.     

Some aspects of the safety of high speed catamarans

A high speed catamaran was involved in an accident off Jersey. No one was injured as a result of the actual accident itself but there were a number of serious injuries sustained by passengers during the evacuation of the vessel. A number of deficiencies in the design of the vessel were identified as a result of the accident and the evacuation of passengers and crew. Access routes and the number of exits were important causes of concern. Lifejackets and life rafts were found to have problems in their use and their specification seemed not to be well adapted to their possible use. Life rafts in particular were found not to be sufficiently robust. The low crew to passenger ratio required passengers to take on roles for which they had neither the expertise nor the training. Crew and passengers all responded to the best of their ability but unnecessary strain was placed on all due to lack of sufficient trained people being available. Hypothermia was not a major problem but if the rescue had taken much longer then there would have been a rapidly increasing number of people affected. Rescue equipment should be improved to cope with this life threatening condition.