Voltage sag distributions caused by power system faults

Voltage sag distributions caused by faults at different voltage levels and experienced by low-voltage customers were established for four different power system areas. The shares of different fault types at each voltage level and the sag propagation throughout the power system were taken into account. The results show that the origin of sags in urban and rural areas tends to be different. These data are needed when, for example, planning measures for sag mitigation in different parts of the power system.     

Dynamic thermal modeling of distribution transformers

A comprehensive test program was performed on a 2500-kVA oil natural-air natural cooling mode (ONAN) transformer without external cooling. It is shown that the hot-spot to top-oil temperature gradient depends on the transformer construction. The top-oil time constant formula, which has already been defined and validated in the authors' previous work related to transformers with external cooling, is modified in order to take into account the basic design differences. The results are verified by thermocouple measurements and tests at varying loading current. The hot-spot and top-oil temperature responses predicted by the IEEE Loading Guide, Annex G, are also compared to the measured values.     

Antimicrobial resistance of fecal aerobic gram-negative bacilli in different age groups in a community

We measured the occurrence of antimicrobial resistance in fecal aerobic gram-negative bacilli by age in community subjects. For none of the eight antimicrobial agents studied were there any statistically significant differences in the carriage rates of resistance in different age groups. Bacterial resistance was common in all age groups, including the children, and occurred for all antimicrobial agents tested.     

Diagnosis of meningococcal meningitis by broad-range bacterial PCR with cerebrospinal fluid

We used broad-range bacterial PCR combined with DNA sequencing to examine prospectively cerebrospinal fluid (CSF) samples from patients with suspected meningitis. Fifty-six CSF samples from 46 patients were studied during the year 1995. Genes coding for bacterial 16S and/or 23S rRNA genes could be amplified from the CSF samples from five patients with a clinical picture consistent with acute bacterial meningitis. For these patients, the sequenced PCR product shared 98.3 to 100% homology with the Neisseria meningitidis sequence. For one patient, the diagnosis was initially made by PCR alone. Of the remaining 51 CSF samples, for 50 (98.0%) samples the negative PCR findings were in accordance with the negative findings by bacterial culture and Gram staining, as well as with the eventual clinical diagnosis for the patient. However, the PCR test failed to detect the bacterial rRNA gene in one CSF sample, the culture of which yielded Listeria monocytogenes. These results invite new research efforts to be focused on the application of PCR with broad-range bacterial primers to improve the etiologic diagnosis of bacterial meningitis. In a clinical setting, Gram staining and bacterial culture still remain the cornerstones of diagnosis.     

Ganciclovir and Its Hemocompatible More Lipophilic Derivative Can Enhance the Apoptotic Effects of Methotrexate by Inhibiting Breast Cancer Resistance Protein (BCRP)

Efflux transporters, namely ATP-binding cassette (ABC), are one of the primary reasons for cancer chemoresistance and the clinical failure of chemotherapy. Ganciclovir (GCV) is an antiviral agent used in herpes simplex virus thymidine kinase (HSV-TK) gene therapy. In this therapy, HSV-TK gene is delivered together with GCV into cancer cells to activate the phosphorylation process of GCV to active GCV-triphosphate, a DNA polymerase inhibitor. However, GCV interacts with efflux transporters that are responsible for the resistance of HSV-TK/GCV therapy. In the present study, it was explored whether GCV and its more lipophilic derivative (1) could inhibit effluxing of another chemotherapeutic, methotrexate (MTX), out of the human breast cancer cells. Firstly, it was found that the combination of GCV and MTX was more hemocompatible than the corresponding combination with compound 1. Secondly, both GCV and compound 1 enhanced the cellular accumulation of MTX in MCF-7 cells, the MTX exposure being 13–21 times greater compared to the MTX uptake alone. Subsequently, this also reduced the number of viable cells (41–56%) and increased the number of late apoptotic cells (46–55%). Moreover, both GCV and compound 1 were found to interact with breast cancer resistant protein (BCRP) more effectively than multidrug-resistant proteins (MRPs) in these cells. Since the expression of BCRP was higher in MCF-7 cells than in MDA-MB-231 cells, and the cellular uptake of GCV and compound 1 was smaller but increased in the presence of BCRP-selective inhibitor (Fumitremorgin C) in MCF-7 cells, we concluded that the improved apoptotic effects of higher MTX exposure were raised mainly from the inhibition of BCRP-mediated efflux of MTX. However, the effects of GCV and its derivatives on MTX metabolism and the quantitative expression of MTX metabolizing enzymes in various cancer cells need to be studied more thoroughly in the future.     

Online classification of single EEG trials during finger movements.

Many offline studies have explored the feasibility of EEG potentials related to single limb movements for a brain-computer interface (BCI) control signal. However, only few functional online single-trial BCI systems have been reported. We investigated whether inexperienced subjects could control a BCI accurately by means of visually-cued left versus right index finger movements, performed every 2 s, after only a 20-min training period. Ten subjects tried to move a circle from the center to a target location at the left or right side of the computer screen by moving their left or right index finger. The classifier was updated after each trial using the correct class labels, enabling up-to-date feedback to the subjects throughout the training. Therefore, a separate data collection session for optimizing the classification algorithm was not needed. When the performance of the BCI was tested, the classifier was not updated. Seven of the ten subjects were able to control the BCI well. They could choose the correct target in 84%-100% of the cases, 3.5-7.7 times a minute. Their mean single trial classification rate was 80% and bit rate 10 bits/min. These results encourage the development of BCIs for paralyzed persons based on detection of single-trial movement attempts.     

Expert evaluation of traffic signs: conventional vs. alternative designs

Traffic sign comprehension is significantly affected by their compliance with ergonomics design principles. Despite the UN Convention, designs vary among countries. The goal of this study was to establish theoretical and methodological bases for evaluating the design of conventional and alternative signs. Thirty-one conventional signs and 1–3 alternatives for each conventional sign were evaluated for their compliance with three ergonomics guidelines for sign design: physical and conceptual compatibility, familiarity and standardisation. Twenty-seven human factors and ergonomics experts from 10 countries evaluated the signs relative to their compliance with the guidelines. Analysis of variance across alternatives revealed that for 19 of the 31 signs, an alternative design received a significantly higher rating in its ergonomics design than the conventional sign with the same meaning. We also found a very high correlation between the experts’ ratings and comprehension from previous studies. In conclusion, many countries use signs for which better alternative designs exist, and therefore UN Convention signs should be re-examined, and ergonomics experts evaluation can serve as a good surrogate for road users’ comprehension surveys.

Practitioner summary: This study presents theoretical and methodological bases for evaluating the design of UN Conventional and alternative traffic signs. Human factors and ergonomics experts evaluated 31 conventional and 68 alternative road signs, based on ergonomics principles for sign design. Results indicated the need to re-examine poorly designed UN Convention signs.     

HMG-17, a chromosomal non-histone protein, shows developmental regulation during organogenesis

A significant portion of patients who present with non-muscle invasive "superficial" bladder cancer develop the muscle "invasive" life-threatening form of the disease during subsequent follow-up. In clinical studies, overexpression of the epidermal growth factor receptor (EGFR) and the p21 ras oncogene have been strongly associated with this phenotypic tumor transition. The marked difference in incidence of invasive bladder cancer in Asia compared to the United States has made us hypothesize that, among other factors, dietary influences have an impact on such tumor progression. A significantly higher dietary consumption of soy products exists in Asia and has led to the notion that the isoflavones present in this diet may contribute to a reduction in the number of invasive transitional cell bladder cancers. In this regard, we sought to determine the effect of genistein, a naturally occurring dietary protein tyrosine kinase (PTK) inhibitor, on the growth and motility of human bladder cancer cell lines with diverse EGFR and p21ras expression phenotypes and corresponding invasive behaviors. These effects were compared with those of tyrphostin, a pure synthetic EGFR inhibitor. Our results indicate that both genistein and tyrphostin are effective inhibitors of bladder cancer motility and growth, key factors in the development of muscle invasive disease. In addition, the growth and motility inhibitory effects of genistein and tyrphostin are observed preferentially in cells that overexpress the EGFR. Cells that have a mutated p21ras but do not overexpress the EGFR are less inhibited by these 2 compounds, suggesting that their effect is primarily directed at the EGFR signal transduction pathways proximal to the p21ras gene. Our results would seem to corroborate the notion that a high dietary intake of isoflavones is a likely explanation for the decreased incidence of invasive bladder cancer.     

Decomposing road freight energy use in the United Kingdom

Applying the techniques of decomposition analysis we estimate the relative contribution of ten variables (termed ‘key ratios’) plus GDP to the change in UK road freight energy use over the period 1989–2004 inclusive. The results are best interpreted as an estimate of the percentage growth in energy consumption that would have resulted from the change in the relevant factor (e.g. length of haul) had the other factors remained unchanged. The results demonstrate that the main factor contributing to the decoupling of UK road freight energy consumption from GDP was the decline in the value of domestically manufactured goods relative to GDP. Over the period 1989–2004 this largely offset the effect of increases in GDP on road freight energy consumption. While the decline in domestic manufacturing was to some extent displaced by increases in imports, the net effect of these supply factors, together with shifts in the commodity mix, has been to reduce UK road freight energy consumption by 30.1%. The net effect on global carbon dioxide (CO₂) emissions is likely to be somewhat less beneficial, since many freight movements associated with the manufacture of imported goods have simply been displaced to other countries.     

Studies on psychomotoric effects and pharmacokinetic interactions of the new calcium sensitizing drug levosimendan and ethanol

Levosimendan (CAS 141505-33-1) is a calcium sensitizing drug intended for the treatment of congestive heart failure. In animal experiments levosimendan has potentiated the sedative effects of ethanol. Due to poor water solubility of the compound, ethanol is used as a diluent in the intravenous formulation. In this study the possible interactions between levosimendan and ethanol in human have been studied. Twelve healthy male volunteers were included in this double-blind, randomized, cross-over study. The study consisted of three treatment periods: levosimendan 1 mg intravenously, levosimendan combined with ethanol orally and ethanol 0.8 g/kg alone. Blood samples for determination of levosimendan and ethanol concentrations were collected for 8 h after the dosing. To observe possible pharmacodynamic interactions psychomotoric tests were made before drug administration and 1h, 2h, 3h and 6h thereafter. These tests included Digit symbol substitution test, Maddox wing, Critical Flicker fusion and VAS-test for subjective assessment of performance status. Plasma levosimendan concentrations were not changed by the concomitant ethanol administration. Ethanol did not alter the pharmacokinetics of levosimendan except the volume of distribution of central compartment which was decreased. Levosimendan did neither affect elimination of ethanol. Levosimendan did not potentiate the psychomotoric effects of ethanol neither did it have any psychomotoric effects itself. In conclusion, levosimendan is not likely to have any psychomotoric adverse effects or any clinically significant interactions with ethanol.