Is it PAO-GAO competition or metabolic shift in EBPR system? Evidence from an experimental study

Reduced EBPR performance in full and bench-scale EBPR studies was linked to the proliferation of GAOs but often time with the lack of any evidence. In this study, a detailed enzymatic study was coupled with batch tests and electron microscopy results for a realistic explanation. The results eliminated the possibility of population shift from PAO to GAO or other non-PAO due to the short batch test period provided which would not allow a population shift and further justified with the electron microscopy results. The results indicate that glycogen serves not only as source of reducing power for PHA production but also serves as an alternative energy source when the poly-P pool of the PAOs is depleted. Slow generation of ATP via glycolytic pathway at 5 degrees C cannot satisfy energy requirements of EBPR cells to complete several cell functions including acetate uptake and PHA storage. However, the glycolytic pathway is efficiently operable at warm temperatures (> 20 degrees C). The reduced performance of enhanced EBPR facilities operated at warm temperature may not be a result of GAO proliferation; instead it may be related the efficient use of the glycolytic pathway by PAOs which results in more glycogen storage and less P uptake, thereby reducing the EBPR performance.     

Effect of Cr additions on the electrical properties of Ni–BaTiO3 ultra-thin multilayer capacitors

Multilayer ceramic capacitors based on BaTiO₃ dielectric compositions and Ni inner electrodes have complex interfacial reactions that impact the continuity of the inner electrode microstructure. Previously we demonstrated that through the addition of Cr to Ni, a significant improvement in the continuity of ultra-thin Ni electrodes in Ni–BaTiO₃ multilayer capacitors could be achieved. Here, the effect of the Cr addition to the nickel electrode pastes is studied with regard to the electrical properties. Low-field electrical measurements demonstrate no major differences between Cr doped Ni and undoped Ni. However, high-field measurements show a significant decrease to the total capacitor resistance. Under a critical electrical bias the conductivity significantly increases due to a Fowler–Nordheim tunneling conduction though the interfacial Schottky barrier at the dielectric–electrode interface; the onset voltage of this conduction is much lower than with the undoped nickel. Based on these results, we evaluate criteria for the selection of an appropriate refractory metal in order to improve the Ni electrode continuity.     

Master Sintering Curve Formulated from Constitutive Models

The classical master sintering curve (MSC) is derived from empirical sintering model and is applicable over a range of heating rates and temperatures. For simplicity, the MSC approach was modified by assuming one dominant densification mechanism to evaluate and predict densification response. However, the concept of MSC can be extended well beyond the original formulation or the subsequent simplifications. To this effect, generalized formulations are proposed based on several constitutive equations including both grain growth and densification. These formulations can be used very effectively to obtain material properties that in turn can be used in finite-element method to improve the accuracy of the simulations.     

Suffix interference in the recall of linguistically coherent speech.

In Exp 1, definitions of low-frequency words were presented for on-line written recall. Each definition was followed by a nonword speech suffix presented in the same voice as the definition, the same nonword presented in a different voice, or a tone. There was a significant reduction in the recall of the terminal words of the definitions in the speech suffix conditions compared with the tone control. This pattern was replicated in Exp 2, in which Ss did not begin their recall until the suffix item or tone was presented, although the magnitude of the suffix effect was reduced in this experiment. In Exp 3, the suffix effect was considerably reduced compared with the suffix effect found with the definitions presented in Exps 1 and 2. This pattern was replicated in Exp 4, in which Ss did not begin their recall of the story sentences until the speech suffix or tone was presented. Results suggest that auditory memory interference can take place for linguistically coherent speech, although the magnitude of the interference decreases as one increases the level of linguistic structure in the to-be-recalled materials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role play for assessing the social competence of psychiatric patients.

This study examined the validity and utility of role play for assessing social competence of chronic psychiatric patients. Demographically matched groups of patients with schizophrenia (n?=?57), schizoaffective disorder (n?=?16), major affective disorder (n?=?33), and a nonpatient control group (n?=?20) were assessed on a role-play test, interview measures of role functioning in the community, and a problem-solving discussion with a significant other. A subsample was reassessed on the same instruments 6 months later. Behavior on the role-play test discriminated the groups, was highly correlated with ratings on the other measures, and was relatively stable over the retest interval. The results were interpreted as providing strong support for the value of role play as a general measure of social functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is "working memory capacity" just another name for word knowledge?

This study is concerned with whether the correlation between complex working memory spans and reading comprehension occurs because the complex spans reflect the capacity of a structural working memory that plays a causal role in comprehension or because a 3rd factor, word knowledge, plays a causal role in both the span tasks and comprehension. If the latter hypothesis is correct, the correlation between word span and reading comprehension should be large when span is tested with low-frequency words but should not occur when span is tested with very familiar words. 90 college students were tested on a simple and a complex version of the word span task with high- and low-frequency words. The Verbal Scholastic Aptitude Test (VSAT) was used as a measure of reading comprehension. The correlation between span and VSAT was somewhat higher when span was tested with low-frequency words, but was significant with both low- and high-frequency words. This suggests that both word knowledge and a content-free working memory play a causal role in the relationship between word span and higher level cognitive tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contrasting biophysical and pharmacological properties of T-type and R-type calcium channels

In contrast to other kinds of voltage-gated Ca2+ channels, the underlying molecular basis of T-type and R-type channels is not well-understood. To facilitate comparisons with cloned Ca2+ channel subunits, we have carried out a systematic analysis of the properties of T-type currents in undifferentiated NG108-15 cells and R-type currents in cerebellar granule neurons. Marked differences were found in their biophysical and pharmacological features under identical recording conditions. T-type channels became activated at potentials approximately 25 mV more negative than R-type channels; however, T-type channels required potentials approximately 15 mV less negative than R-type channels to be available. Accordingly, T-type channels display a much larger overlap between the curves describing inactivation and activation, making them more suitable for generating sustained Ca2+ entry in support of secretion or pacemaker activity. In contrast, R-type channels are not equipped to provide a steady current, but are very capable of supplying transient surges of Ca2+ influx. In response to a series of increasingly strong depolarizations T-type and R-type Ca2+ channels gave rise to very different kinetic patterns. T-type current records crossed each other in a characteristic pattern not found for R-type currents. These biophysical distinctions were independent of absolute membrane potential and were, therefore, complementary to the conventional categorization of T- and R-type Ca2+ channels as low- and high-voltage activated. R-type channels deactivated approximately eight-fold more quickly than T-type channels, with clear consequences for the generation of divalent cation influx during simulated action potentials. Pharmacological comparisons revealed additional contrasts. R-type current was responsive to block by omega-Aga IIIA but not nimodipine, while the opposite was true for T-type current. Both channel types were potently inhibited by the non-dihydropyridine compound mibefradil. In all respects examined, R-type currents were similar to currents derived from expression of the alpha1E subunit whereas T-type currents were not.     

Working-memory capacity and the control of attention: The contributions of goal neglect, response competition, and task set to Stroop interference.

Individual differences in working-memory (WM) capacity predicted performance on the Stroop task in 5 experiments, indicating the importance of executive control and goal maintenance to selective attention. When the Stroop task encouraged goal neglect by including large numbers of congruent trials (RED presented in red), low WM individuals committed more errors than did high WM individuals on the rare incongruent trials (BLUE in red) that required maintaining access to the "ignore-the-word" goal for accurate responding. In contrast, in tasks with no or few congruent trials, or in high-congruency tasks that followed low-congruency tasks, WM predicted response-time interference. WM was related to latency, not accuracy, in contexts that reinforced the task goal and so minimized the difficulty of actively maintaining it. The data and a literature review suggest that Stroop interference is jointly determined by 2 mechanisms, goal maintenance and competition resolution, and that the dominance of each depends on WM capacity, as well as the task set induced by current and previous contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of thromboelastography with heparinase or protamine sulfate added in vitro during heparinized cardiopulmonary bypass

Thromboelastography (TEG) has been used after cardiopulmonary bypass (CPB) to diagnose excessive postoperative hemorrhage. Conventional TEG during CPB is not possible due to the sensitivity of the TEG to even small amounts of heparin, which produces a nondiagnostic tracing. The purpose of this study was to compare heparin neutralization using heparinase or protamine in TEG blood samples obtained during CPB. TEG testing was performed on 48 patients before, during and after CPB. Tissue plasminogen activator activity and antigen were measured on a subset of 32 patients. We found: 1) heparinase neutralized at least 10 IU/ml heparin while 1.6 ug/ml protamine neutralized up to 7 IU/ml heparin, 2) in samples with complete heparin neutralization by both methods, there was no significant difference in the R values, 3) while there was good correlation for other TEG parameters between heparinase and protamine treated samples, heparinase treatment produced shorter K values and higher angle, MA and A60, 4) while fibrinolysis was detected using both methods, heparinase treatment suppressed fibrinolysis in the TEG in both samples from patients and after in vitro addition of tissue plasminogen activator, 5) TEG was not a sensitive indicator of t-PA activity, detecting only 21% of samples with increased t-PA activity during bypass, and 5) heparinase was at least 100 times more expensive than protamine. We conclude that while both heparinase and protamine can be used to neutralize heparin in TEG samples obtained during CPB, protamine neutralization is more sensitive to fibrinolysis and less expensive, but the protamine dose must be carefully selected to match the heparin level used at individual institutions.     

A 1000-measurement frames/second ERT data capture system with real-time visualization

This paper describes the design of a 16-electrode high-speed (1000 frames/s) electrical resistance tomography system with real-time visualization. The instrument utilizes a switched dc current pulse technique in conjunction with parallel data acquisition to achieve the high-data capture rates. The reconstruct algorithm is implemented using a single iteration Newton-Raphson method, which executes in under 1 ms. Data sets are presented that verify its operation. A calibration technique is described which improves the sensitivity of the current pulse measuring system and allows phenomena such as the dynamics of nonuniform slurries and gas distribution in aeration systems to be investigated. Furthermore, the calibration scheme described compensates significantly for the effect of impellers and baffles present in the measuring tank and allows more accurate reconstructions to be performed in the areas of interest.