Insights into the cITP process using on-line NMR spectroscopy

Recently, capillary isotachophoresis (cITP) has been coupled on-line with nuclear magnetic resonance (NMR) to enhance analysis of dilute charged analytes through sample concentration and separation. This study focuses on the unique detection capabilities of NMR to noninvasively examine the cITP process and obtain diagnostic information. With their enhanced mass sensitivity, microcoil NMR probes provide optimal detection for cITP/NMR. Whereas previous studies used deuterated buffers, a 1H NMR observable leading electrolyte, tetramethylammonium acetate, is employed here to better track cITP progression. Fortuitously, the 1H chemical shift of the acetate methyl resonance depends on pD. Hence, by using a calibration curve, the solution pD can be determined on-line during cITP. Similarly, intracapillary temperature can be measured in cITP/NMR by observing the HOD chemical shift. To obtain accurate chemical shift measurements, charge-neutral tert-butyl alcohol is added to all cITP electrolyte solutions as an internal reference. As an ancillary benefit, line width measurements of the ubiquitous tert-butyl alcohol enable NMR spectral resolution to be examined throughout the experiment. Capable of providing quantitative results, NMR simultaneously determines the concentrations of the leading ion, sample, and counterion over the course of the cITP experiment.     

Control principles in flexible manufacturing

Flexible manufacturing systems present a setting in which application of control concepts can be crucial. Today, some concepts are in place where needed, some are waiting to be applied, and some are yet to be created. This paper is a status report on FMS control technology, based on ongoing work at the The Charles Stark Draper Laboratory in the development of decision support systems for FMSs.     

Heritability and psychological tests.

Comments on M. B. Jones's (see record 1971-07242-001) article advocating the use of heritability (HER) as a criterion in psychological test construction, pointing out a disadvantage of using HER as a criterion. One cannot maximize the HER of an intelligence test and then use that test to demonstrate that intelligence is inherited. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of cuing on recall from categorized word lists.

Explored the retrieval-deficit hypothesis by comparing free-recall under cued and noncued conditions in 2 groups of 36 5- and 8-yr-olds. On a 16-word list containing either 2, 4, or 8 categories, Ss received 2 trials of noncued recall. The 2nd trial was immediately followed by a test for cued recall. A comparison between cued recall performance and noncued recall performance on Trial 2 indicates that the younger children benefited more than the older children from the cuing procedure. For both age groups, there were effects of cuing on both the number of categories recalled and the number of items per category recalled. Clustering was observed at both age-levels but appeared unrelated to recall performance. Some of the results are discussed in connection with a retrieval deficit hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A picture integration task for measuring iconic memory in schizophrenics.

Two previous studies by the 1st author et al (1977) and G. Sperling (1960) using different techniques (partial report and backward masking) have found at least some subgroups of schizophrenics deficient in iconic memory. Both hypothesized that the icon in some schizophrenics might be either weakly formed, limited in capacity, or abnormal in duration, but neither study was able to test the qualities of the icon independent of possible transfer difficulties. The present study with 50 male 18–55 yr old psychiatric patients (35 schizophrenics and 15 nonpsychotics) developed a picture integration task that was analogous to C. W. Eriksen and J. F. Collins's (1973) random dot integration. With this task, the capacity and decay of the icon independent of transfer to short-term store was assessed. The icon itself was found intact in all schizophrenics. Other explanations are suggested for schizophrenics' inadequate partial report and backward masking performance. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of parametric material, energy, and emission inventories for wafer fabrication in the semiconductor industry

Currently available data suggest that most of the energy and material consumption related to the production of an integrated circuit is due to the wafer fabrication process. The complexity of wafer manufacturing, requiring hundreds of steps that vary from product to product and from facility to facility and which change every few years, has discouraged the development of material, energy, and emission inventory modules for the purpose of insertion into life cycle assessments. To address this difficulty, a flexible, process-based system for estimating material requirements, energy requirements, and emissions in wafer fabrication has been developed. The method accounts for mass and energy use atthe unit operation level. Parametric unit operation modules have been developed that can be used to predict changes in inventory as the result of changes in product design, equipment selection, or process flow. A case study of the application of the modules is given for energy consumption, but a similar methodology can be used for materials, individually or aggregated.     

A homology model of penicillin acylase from Alcaligenes faecalis and in silico evaluation of its selectivity

A three-dimensional model of the relatively unknown penicillin acylase from Alcaligenes faecalis (PA-AF) was built up by means of homology modeling based on three different crystal structures of penicillin acylase from various sources. An in silico selectivity study was performed to compare this homology model to the structure of the Escherichia coli enzyme (PA-EC) in order to find any selectivity differences between the two enzymes. The program GRID was applied in combination with the principal component analysis technique to identify the regions of the active sites where the PAs potentially engage different interactions with ligands. These differences were further analyzed and confirmed by molecular docking simulations. The PA-AF homology model provided the structural basis for the explanation of the different enantioselectivities of the enzymes previously demonstrated experimentally and reported in the literature. Different substrate selectivities were also predicted for PA-AF compared to PA-EC. Since no crystallographic data are available for PA-AF to date, the three-dimensional homology model represents a useful and efficient tool for fully exploiting this attractive and efficient biocatalyst, particularly in enantioselective acylations of amines.