Antimicrobial properties of 1‐monoacylglycerols prepared from undecanoic (C11:0) and undecenoic (C11:1) acid

Antimicrobial activity of monoacylglycerols (MAG) with odd number of carbons prepared from undecanoic (MAG C11:0) and undecenoic (MAG C11:1) was investigated. Data showed that both studied substances successfully inhibited Gram‐positive cocci (Staphylococcus aureus) and spore‐forming rods (Bacillus cereus). Gram‐negative bacteria were highly resistant against MAG C11:0 and showed considerable tolerance against MAG C11:1. Minimum inhibitory concentration (MIC) of MAG C11:1 was possible to determine for Escherichia coli only. Complete inhibition of three fungi genera (Alternaria, Cladosporium, Trichothecium) was achieved using MAG C11:1 with a concentration higher than 750 µg/mL. The growth of Aspergillus niger, Mucor racemosus, Phoma, Scopulariopsis, Trichoderma was significantly reduced. Generally, MAG C11:1 was more efficient than MAG C11:0 against all tested microorganisms. Due to a rich production of degradation enzymes, some fungi species surprisingly adapted their metabolism during growth and were even able to utilise tested MAG as a source of carbon. Practical applications: MAG composed of fatty acids with odd number of carbons in molecule are a promising group of substances applicable in food industry and cosmetics. They represent materials with broad spectrum of antimicrobial activity, especially against Gram‐positive bacteria. More efficient MAG C11:1 with a double bond in molecule can be recommended for reduction of S. aureus that cause food enterotoxicosis.     

Transmission of video telephony images over wireless channels

In this paper, the effects of digital transmission errors on H.263 codecs are analyzed and the transmission of H.263 coded video over a TDMA radio link is investigated. The impact of channel coding and interleaving on video transmission quality is simulated for different channel conditions. Fading on radio channels causes significant transmission errors and H.263 coded bit streams are very vulnerable to erros. Powerful Forward Error Correction (FEC) codes are therefore necessary to protect the data so that it can be successfully transmitted at acceptable signal power levels. FEC, however, imposes a high bandwidth overhead. In order to make best use of the available channel bandwidth and to alleviate the overall impact of errors on the video sequence, a twolayer data partitioning and unequal error protection scheme based on H.263 is also studied. The scheme can tolerate more transmission errors and leads to more graceful degradation in quality when the channel SNR decreases. In lossy environments, it can improve the video transmission quality at no extra bandwidth cost.Part of this paper was presented at IS&T/SPIE Symposium on Electronic Imaging, San Jose, CA, USA, January 1996.     

Effect of freeze storage on the volatiles of butter

The changes in the volatile components of three butter samples were studied during freeze storage for 7.5 months. The amount of carbonyl increased and reached a maximum after 4.5 months of storage. Afterwards the carbonyl decreased. The lactons reached its maximum after storage of 3 month. The increase of the carbonyls caused by peroxidation of unsaturated fatty acids was taken as indication for the deterioration of the butter samples during storage.     

Using a pulse generator to check flux meters

Measurement Techniques -     

Power quality affects teacher wellbeing and student behavior in three Minnesota Schools

BACKGROUND: Poor power quality (dirty electricity) is ubiquitous especially in schools with fluorescent lights and computers. Previous studies have shown a relationship between power quality and student behavior/teacher health. OBJECTIVES: The purpose of this study is to determine the ability of power line filters to reduce dirty electricity in a school environment and to document changes in health and behavior among teachers and students. METHOD: We installed Graham Stetzer filters and dummy filters and measured power quality in three Minnesota Schools. Teachers completed a daily questionnaire regarding their health and the behavior of their students for an 8-week period. Teachers were unaware of which filters were installed at any one time (single blind study). RESULTS: Dirty electricity was reduced by more than 90% in the three schools and during this period teacher health improved as did student behavior in the middle/elementary schools. Headaches, general weakness, dry eyes/mouth, facial flushing, asthma, skin irritations, overall mood including depression and anxiety improved significantly among staff. Of the 44 teachers who participated 64% were better, 30% were worse, and 6% did not change. Behavior of high school students did not improve but elementary/middle school students were more active in class; more responsive, more focused; had fewer health complaints; and had a better overall learning experience. CONCLUSIONS: Dirty electricity in schools may be adversely affecting wellbeing of teachers and behavior of their students, especially younger students in middle and elementary school. Power line filters improve power quality and may also protect those who are sensitive to this energy. Work on electric and magnetic field metrics with and without Stetzer filters urgently needs to be carried out to determine just what characteristics of the dirty electricity may be interacting with the people.     

Nano-sized ceramic inks for drop-on-demand ink-jet printing in quadrichromy

Nano-sized ceramic inks suitable for ink-jet printing have been developed for the four-colours CMYK (cyan, magenta, yellow, black) process. Nano-inks of different pigment composition (Co(1-x)O, Au(0), Ti(1-x-y)Sb(x)Cr(y)O2, CoFe2O4) have been prepared with various solid loadings and their chemicophysical properties (particle size, viscosity, surface tension, zeta-potential) were tailored for the ink-jet application. The pigment particle size is in the 20-80 nm range. All these nano-suspensions are stable for long time (i.e., several months) due to either electrostatic (high zeta-potential values) or steric stabilization mechanisms. Both nanometric size and high stability avoid problems of nozzle clogging from particles agglomeration and settling. Nano-inks have a Newtonian behaviour with relatively low viscosities at room temperature. More concentrated inks fulfil the viscosity requirement of ink-jet applications (i.e., < 35 mPa x s) for printing temperatures in between 30 and 70 degrees C. Surface tension constraints for ink-jet printing are fulfilled by nano-inks, being in the 35-45 mN x m(-1) range. The nano-sized inks investigated behave satisfactorily in preliminary printing tests on several unfired industrial ceramic tiles, developing saturated colours in a wide range of firing temperatures (1000-1200 degrees C).     

An integrated LC-ESI-MS platform for quantitation of serum peptide ladders. Application for colon carcinoma study

Mounting evidence indicates that MS analysis of the human blood peptidome allows to distinguish between cancer and non-cancer samples, giving promise for a new MS-based diagnostic tool. However, several aspects of already published work have been criticized and demand for more methodical approach has been formulated. Motivated by this we undertook a systematic study of the plasma and serum peptidome using an integrated ESI-LC-MS-based platform, equipped with new data analysis tools for relative and absolute peptide quantitation. We used a high resolution LC-ESI-MS to analyze well-separated MS signals corresponding to peptides, and measured the variability of >1000 peptide signal amplitudes across a set of plasma and serum samples from healthy individuals. By spiking serum samples with known amounts of isotopically labeled versions of a selected set of peptides we measured the variability of their absolute concentration in this sample set and demonstrated a strong influence of clotting time on the concentration of these peptides in serum. Finally, we used this new LC-ESI-MS analytical platform for the differential analysis of healthy versus colon cancer serum samples and found that it was possible to distinguish the two groups with 89.8% sensitivity and 94.6% specificity.     

Preparation of dialdehyde cellulose hydrazone derivatives andevaluating their efficiency for sewage wastewater treatment

The cellulose hydrazone derivative is a novel product prepared from dialdehyde cellulose with 2-hydrazino-3,5,6,7tetrahydrocyclopentanethieno[2,3-d]-pyrimidin-4(4H)-one under suitably selected conditions. It was found that the reaction of dialdehyde cellulose with the 2-hydrazino derivative decreased progressively in the series cellulose powder, viscose wood pulp and cotton linter. The principal objective of this research was to evaluate the effectiveness of dialdehyde cellulose hydrazone derivatives on sewage wastewater settling, percentage of total suspended solids (TSS), carbon oxygen demand (COD), and iron and chromium removal. About 30-50% of chlorine was removed after treatment using dialdehyde cellulose hydrazone derivatives, thus indicating their good efficiency for halogen removal. Cellulose hydrazone derivatives were recommended as good coagulants and removed Fe and Cr by 73.9% and 66.7%, respectively. Jar tests revealed that the wastewater was best treated with the addition of chemical coagulants such as FeCl₃ or Al₂(SO₄)₃ combined with cellulose hydrazone derivatives at optimum doses. The optimum conditions produced better cleaning-up and improved removal of COD and TSS up to 77% and 97%, respectively.