Comment and discussion on digital processing of PD pulses

Some of the more salient aspects of the digital processing technology of PD signals are examined. Most of the efforts in this field are concentrated on the application of digital analyzers for pulse height analysis, pattern recognition and identification of the physical phenomena. It is demonstrated that errors in the signal processing unit can lead to dominant mistakes in the interpretation of the test results     

Assessing declarative memory in schizophrenia using Wisconsin Card Sorting Test stimuli: the Paired Associate Recognition Test

The Paired Associate Recognition Test (PART) was developed to measure declarative memory using Wisconsin Card Sorting Test (WCST) stimuli, so that both tasks could be administered during functional neuroimaging to differentiate memory and executive function, and associated frontal and temporal lobe activation in schizophrenia. The current study was designed to compare PART and WCST performance in schizophrenic patients and to examine effects of medication and symptomatology. The PART, WCST, and standard declarative memory tasks were administered to 30 chronic schizophrenic patients and 30 matched healthy control subjects. Supporting task validity was the finding that patients were equally impaired on the PART and the WCST. Neuroleptics did not appear to affect performance. The effect of anticholinergic medication correlated negatively with WCST performance in a small subsample. Severity of schizophrenia-specific symptoms measured at intake on the Brief Psychiatric Rating Scale correlated negatively with performance on the WCST. These results support the application of the PART and WCST in future functional neuroimaging studies.     

Assessment of iron bioavailability from twenty elite late‐maturing tropical maize varieties using an in vitro digestion/Caco‐2 cell model

An in vitro digestion/Caco‐2 cell model was used to assess iron bioavailability of twenty elite late‐maturing tropical maize varieties grown in three diverse agroecologies in West and Central Africa (WCA). Kernel‐iron concentration of the varieties, averaged across locations, varied from 19.2 to 24.4 mg kg^?1, while mean kernel‐zinc concentration ranged between 19.4 and 24.6 mg kg^?1. Significant differences in iron bioavailability were observed among varieties, but the environment had no significant effect. Mean bioavailable iron ranged between 14% below and 43% above the reference control variety, TZB‐SR. Variety DMR‐LSR‐Y with the highest concentrations of kernel‐iron and ‐zinc of 24–25 mg kg^?1 across the three locations had a similar quantity of bioavailable iron as the reference control, TZB‐SR. In the long run this variety could be potentially effective in reducing iron deficiency because of its high kernel‐iron. The most promising varieties were Mid‐altitude STR synthetic and ACR91SUWAN‐1‐SRC1. They had kernel‐iron and ‐zinc levels of 22–24 mg kg^?1 and bioavailable iron 24–36% higher than the reference control, TZB‐SR. Additional research is necessary to determine if the increases in kernel‐iron concentration and bioavailable iron observed in this study can significantly improve the iron status of individuals in WCA at risk for iron deficiency. Copyright © 2004 Society of Chemical Industry     

PET regional cerebral blood flow change during working and declarative memory: relationship with task performance

Functional and anatomical relationships between working and declarative memory were investigated by contrasting regional cerebral blood flow (rCBF) change during standard working (Wisconsin Card Sorting Test, WCST) and declarative memory (Paired Associate Recognition Test, PART) tasks using identical stimulus-response modalities. The tasks and a resting baseline were administered to 30 participants (16 men, 14 women) during successive 10-min positron emission tomography 15O-water measures of rCBF. For both tasks, rCBF increased over baseline in inferior frontal and occipitotemporal regions, with more consistent dorsolateral prefrontal activation for WCST than PART. Additional orbitofrontal increases and dorsomedial decreases were seen for the PART. Activation patterns diverged when performance was considered. For the WCST, high performers activated dorsolateral and inferior frontal regions, whereas top PART performers activated only the occipitotemporal region. These results suggest operation of a frontotemporal network subserving both types of memory function that becomes more focal as performance increases.     

Effect of tea phenolics on iron uptake from different fortificants by Caco-2 cells

The in vitro effects of tea phenolics on Fe uptake from different fortificants (FeSO₄, FeCl₃, FeEDTA) by Caco-2 cells were compared. Cell cultures were exposed to catechin, tannic acid, green or black tea solutions, added within Fe-containing solution, or used to pre-treat cell cultures before Fe-exposure. Cell ferritin formation was used as a measure of Fe uptake. Reverse phase chromatography was used to identify specific phenolics in tea solutions, and the Fe-binding catechol and galloyl groups were determined spectrophotometrically. The results showed a positive effect of catechin on Fe uptake only from dissociable Fe sources, and a marked inhibitory effect of tannic acid regardless of the Fe source. Tea phenolics exhibit similar inhibitory patterns on Fe uptake from FeCl₃ and FeEDTA solutions; however, the Fe uptake from FeSO₄ solutions was significantly less affected. These data improve the understanding of interactions by which tea phenolics affect Fe uptake at the intestinal level.     

Modernized risk management in offshore development

Ten years of intensive technical development of the Condeep concrete platforms for the offshore industry has resulted in the development of a corporate management system that provides management with a comprehensive view of all risks and possibilities listed in order of priority, based on their consequences. Not only is this information provided in minimum time, but it also includes the traditional taboos of traditional risk management, which are normally hidden. The new risk management principles applied are outlined.     

Frontotemporal cerebral blood flow change during executive and declarative memory tasks in schizophrenia: A positron emission tomography study.

Schizophrenia affects prefrontal and temporal-limbic networks. These regions were examined by contrasting regional cerebral blood flow (rCBF) during executive (Wisconsin Card Sorting Test [WCST]), and declarative memory tasks (Paired Associate Recognition Test [PART]). The tasks, and a resting baseline, were administered to 15 patients with schizophrenia and 15 healthy controls during 10 min positron emission tomography 1?O-water measures of rCBE Patients were worse on both tasks. Controls activated inferior frontal, occipitotemporal, and temporal pole regions for both tasks. Similar results were obtained for controls matched to level of patient performance. Patients showed no activation of hypothesized regions during the WCST and activated the dorsolateral prefrontal cortex during the PART. On the PART, occipitotemporal activation correlated with better performance for controls only. Better WCST performance correlated with CBF increase in prefrontal regions for controls and in the parahippocampal gyrus for patients. Results suggest that schizophrenia may involve a breakdown in the integration of a frontotemporal network that is responsive to executive and declarative memory demands in healthy individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Calcium, zinc, and iron bioavailabilities from a commercial human milk fortifier: a comparison study

Adding human milk fortifiers (HMF) to human milk (HM) is one way of overcoming the nutrient deficits found in the latter. In this study, the bioavailabilities of calcium, zinc, and iron in S-26/SMA HMF added to HM were compared with those in HM fortified with various bovine milk proteins: alpha-lactalbumin, colostrum, caseinate, casein phosphopeptides, and whey protein concentrate. The bioavailability of each mineral was assessed using an in vitro digestion/Caco-2 cell culture model. Calcium and zinc uptake by the cells was traced with radioisotopes; iron uptake was assessed via cell ferritin levels. Samples were prepared on an equal protein content basis and with added calcium, but no zinc or iron was added. Results revealed that calcium uptake from HM + S-26/SMA was not different from any of the HM fortified with the bovine milk proteins, except for unfortified HM and HM + colostrum in which calcium uptake was significantly lower (-89 and -38%, respectively). Uptake of zinc and iron were significantly higher for HM + S-26/SMA than for the other HM + fortifiers.     

Continuous recording and stochastic analysis of PD

We describe the design and use of a digital partial discharge (PD) data recording system capable of continuous real-time recording of PD pulse trains. The recording system consists of a custom two-channel PD digitizer coupled to a personal computer via a 10-bit parallel interface. The digitizer is under software control with the resulting data being stored in binary files on the computer's hard disk. The stored data subsequently are subjected to stochastic analysis using appropriate computer software. Because all data are retained and the computer provides the desired stochastic analysis of data files, the new system is well suited to investigate non-stationary PD behavior such as encountered in aging studies. By way of illustration, the new system was used to determine the time-varying stochastic behavior of ac-generated PD from point-to-dielectric gaps in air where the insulation material was cast epoxy with aluminum oxide filler. The results confirm and extend previous measurements made with an analog stochastic analyser. With these sample results, we demonstrate how the system allows detailed stochastic analyses not possible with data obtained from existing conventional PD measurement systems     

Reliability, performance characteristics, construct validity, and an initial clinical application of a visual object learning test (VOLT)

Whereas verbal learning has received considerable attention by cognitive neuropsychology, spatial object learning has been more resistant to study. The paucity of visual learning data has hampered attempts to clarify if visual learning has unique features with specialized neural substrates. In schizophrenia, severe verbal learning impairment has been established, but lack of comparable visual learning measures has thwarted the dissociation of verbal and visual abilities. The Visual Object Learning Test (VOLT) was developed to examine aspects of visual-spatial learning and memory in a manner analogous to available verbal tests. Studies were performed to establish normative performance characteristics, convergent and divergent validity, and the sensitivity of the VOLT to detection of individual differences in normal (through sex and age) and pathologic variability (through persons with schizophrenia). The results indicated excellent internal consistency, convergent and divergent validity, and sensitivity to the effects of aging and pathology. Persons with schizophrenia were impaired in both learning and retention. The authors conclude that memory impairment in schizophrenia may not be specific to verbal learning.