Behavioral influences of proximal alarms

Confidence in and responses to an unreliable test alarm were studied in the presence of nearby unspecified alarms. The test alarm's reliability rate was represented as averaging "true" only 50% or 60% of the time. Confidence or response rates ranged proportionately from 23% to 97% with the number of active alarms within 5, 6, 7, or 9 annunciator arrays. Adjacent alarms resulted in confidence estimates that were higher (by about 10%) than those with the same number of active alarms spaced up to 3 positions away. Simultaneously activated alarms resulted in a more than 20% increase in "true" responses compared with the same number of alarms offset in time by up to 32 s, regardless of which came first. Active alarms "known" to be functionally related to, or independent of, the test alarm substantially raised or lowered responding but did not completely overcome prior effects. These findings indicate that presumptions that operators' responses are not influenced by nearby alarms, regardless of their function, may be unwarranted. Applications of this research include suggestions to improve responding and training recommendations.     

Packed capillary reversed-phase liquid chromatography with high-performance electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry for proteomics

In this study, high-efficiency packed capillary reversed-phase liquid chromatography (RPLC) coupled on-line with high-performance Fourier transform ion cyclotron resonance (FTICR) mass spectrometry has been investigated for the characterization of complex cellular proteolytic digests. Long capillary columns (80-cm) packed with small (3-micron) C18 bonded particles provided a total peak capacity of approximately 1000 for cellular proteolytic polypeptides when interfaced with an ESI-FTICR mass spectrometer under composition gradient conditions at a pressure of 10,000 psi. Large quantities of cellular proteolytic digests (e.g., 500 micrograms) could be loaded onto packed capillaries of 150-micron inner diameter without a significant loss of separation efficiency. Precolumns with suitable inner diameters were found useful for improving the elution reproducibility without a significant loss of separation quality. Porous particle packed capillaries were found to provide better results than those containing nonporous particles because of their higher sample capacity. Two-dimensional analyses from the combination of packed capillary RPLC with high-resolution FTICR yield a combined capacity for separations of > 1 million polypeptide components and simultaneously provided information for the identification of the separated components based upon the accurate mass tag concept previously described.     

Design and performance of an ESI interface for selective external ion accumulation coupled to a Fourier transform ion cyclotron mass spectrometer

The coupling of Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with electrospray ionization has advanced the analysis of large biopolymers and provided the basis for high-throughput protein characterization (e.g., for rapid "proteome" analyses). In this work, the combination of high-performance capillary liquid chromatography with FTICR mass spectrometry and external ion accumulation has been shown to increase both sensitivity and analysis duty cycle. Instrument versatility is further improved by ion preselection followed by ion accumulation in an external linear quadrupole ion trap. The interface was tested with a 3.5-T FTICR mass spectrometer and evaluated with a number of peptides and proteins whose molecular weights ranged from 500 to 66000. A significant increase in the sensitivity, duty cycle, and dynamic range over that of the previously used accumulated trapping was achieved, exhibiting a detection limit of approximately 10 zmol (approximately 6000 molecules) for smaller proteins such as cytochrome c. Capillary LC external accumulation interface with FTICR was successfully applied for the study of whole-proteome mouse tryptic digests.     

Short communication: effects of X-rays on growth and germinal tissue of calves

A study was carried out to measure the growth and germinal tissue responses of young bull calf whose testicles were exposed to different levels of high energy, pulsed beams (X rays). Treatments (absorbed doses) were 0, 1530, 1980, 3060, or 6300 rads. Body weights were measured monthly for 10 mo; testosterone concentrations were measured in mo 2 and 5. At the end of the study, scrotal circumferences were measured, and testes were removed and weighed. Sections of testes were taken, processed, and evaluated for effects on germinal epithelium. Treatments did not affect body weights or weight gains. Testosterone concentrations at mo 5 generally decreased with increased energy dose. Testicular weights were not different among treatments; generally, scrotal circumferences decreased and germinal tissue degeneration increased as the absorbed dose was increased.     

Molecular cloning and structural analysis of the gene encoding Bacillus cereus exochitinase Chi36

The chi36 gene encoding exochitinase Chi36 was cloned from a Bacillus cereus 6E1 subgenomic library. The chi36 open reading frame is 1080 bp long encoding a Chi36 precursor protein of 360 amino acids, consisting of a 27 amino acid N-terminal signal peptide and a 333 amino acid sequence found in the mature Chi36 protein of 36.346 kDa. Chi36 shows significant amino acid sequence similarity to many bacterial chitinases, but has highest similarity to B. circulans WL-12 chitinase D. Chi36 belongs to subfamily B of bacterial chitinases in family 18 of glycosyl hydrolases. Chi36 shows a simple and compact structural organization composed of an N-terminal signal peptide and a C-terminal (beta/alpha)8-barrel catalytic domain (CaD). The Chi36 signal peptide is recognized by Escherichia coli, allowing Chi36 secretion. Chi36 is the first one-domain (CaD) bacterial chitinase cloned from B. cereus.     

Evaluation of a second derivative UV/visible spectroscopy technique for nitrate and total nitrogen analysis of wastewater samples

A method for nitrate analysis based on second derivative UV/Visible spectroscopy was developed by Simal et al. (1985: Simal J., Lage M. A., and Iglesias I. (1985) Second derivative ultraviolet spectroscopy and sulfamic acid method for determination of nitrates in water. J. Assoc. Analyt. Chem. 68, 962-964) and Suzuki and Kuroda (1987: Suzuki, N. and Kuroda R. (1987) Direct simultaneous determination of nitrate and nitrite by ultraviolet second-derivative spectrophotometry. Analyst 112, 1077-1079), and later modified for the analysis of total nitrogen in aqueous samples of varying nitrate:organic nitrogen ratios (Crumpton et al., 1992: Crumption W. G., Isenhart T. M. and Mitchell P. D. (1992) Nitrate and organic N analyses with second-derivative spectroscopy. Limnol. Oceanogr. 37, 907-913). The procedure uses the second derivative of the absorption spectrum for nitrate (NO3-), which has a peak at approximately 224 nm that is proportional to the NO3- concentration. Samples for total N analysis are first oxidized to NO3- by persulfate digestion. The objectives of this study were to: (1) test the accuracy and precision of the second derivative method through the use of NIST-traceable wastewater check samples; (2) determine whether the second derivative method for nitrate analysis can be used for wastewater samples and whether the method compares favorably with other currently used nitrate analysis methods; and (3) use the method to analyze wastewater samples containing a range of nitrate and total nitrogen concentrations. Our results indicated that the method needed to be modified to include a longer digestion time (60 min) and dilution of samples prior to digestion (if needed). With the modified method, nitrogen recoveries were not significantly different (P > or = 0.05) from samples with known N concentrations. In addition, nitrate concentrations in constructed wetland and wastewater samples analyzed by both second derivative spectroscopy and ion chromatography were not significantly different. Total nitrogen concentrations in wastewater samples also compared favorably to the same samples analyzed by Kjeldahl digestion. The method is faster, simpler, requires smaller sample volumes, and generates less waste than many EPA-approved methods of N analysis, and may offer a suitable alternative to current methods for analysis of nitrate and total N in wastewater samples.     

Wastewater treatment sludge as a raw material for the production of Bacillus thuringiensis based biopesticides

Seven wastewater sludges of different origins and types were used as an alternate culture medium for producing Bacillus thuringiensis variety kurstaki HD-1. The sludge samples were used under three different preparations: without pre-treatment, with acid treatment (hydrolysed sludge) and the supernatant obtained after centrifugation of the hydrolysed sludge. The sludge composition varied widely with origin and the type of sludge. Growth and sporulation were evaluated by the total viable cell count and spore count of the preparations. Growth, sporulation and endotoxin production were affected by the sludge origin. Hydrolysed sludge gave the highest viable cell and spore counts while the liquid phase (supernatant) gave the lowest. Non-hydrolysed primary sludge from Valcartier was unable to sustain bacterial growth because of its low pH. Bioassays were conducted against larvae of spruce budworm to evaluate entomotoxic potential of the preparations obtained. In general, sludge hydrolysis increased the entomotoxicity yields. Similar entomotoxicity was observed in Black Lake secondary sludge (4100 IU/microL) as that obtained in the reference soya medium (3800 IU/microL). The use of the sludge supernatant (liquid phase) was not recommended due to the low entomotoxic potential obtained.     

低成本高性能的数字阀

电与液结合所带来的好处已有许多资料证明。这种结合产生的极高精度及控制的灵活性,远远超出了全机械的结构。然而,这种系统的价格往往达到数千美元。所以,在许多情况下,使它们的应用限制在与所要求的性能相比,成本是次要的场合。以上这样的情况可以通过一种新的方法——流体传动伺服技术得到改变。凭借今天的微处理机的本领及速度,就有可能使相对简单的机械元件成为高性能的液压和气动系统,而成本大大降低。