Conformational dynamics of cytochrome P-450cam as monitored by photoacoustic calorimetry

Conformational transitions of cytochrome P-450cam following the dissociation of CO from the ferrous heme were investigated by using photoacoustic calorimetry. The effect of substrate association on the acoustic signal was also examined. Results show that the conformational dynamics of cytochrome P-450cam substrate-free protein occur faster than 10 ns, which is the time scale of the instrument response. The enthalpy and volume change for the dissociation reaction are 2.2 kcal mol-1 and 1.8 mL mol-1, respectively. Upon addition of camphor, the reaction is markedly slowed. An intermediate is formed whose lifetime is 130 ns at 17 degrees C. The overall enthalpy and volume changes are -15.9 kcal mol-1 and 10.3 mL mol-1, respectively. These results, together with published transient Raman spectra [Wells, A. V., Pusheng, L., Champion, P. M., Martinis, S. A., & Sligar, S. G. (1992) Biochemistry 31, 4384-4393] suggest that camphor leaves the heme pocket concomitant with the photoinduced expulsion of CO into the solvent and induces a considerable conformational change in the protein.     

Optimized design and fabrication of a microfluidic platform to study single cells and multicellular aggregates in 3D

A microfluidic platform for cell motility analysis in a three-dimensional environment is presented. The microfluidic device is designed to study migration of both single cells and cell spheroids, in particular under spatially and temporally controlled chemical stimuli. A layout based on a central microchannel confined by micropillars and two lateral reservoirs was selected as the most effective. The microfluidics have an internal height of 350 μm to accommodate cell spheroids of a considerable size. The chip is fabricated using well-established micromachining techniques, by obtaining the polydimethylsiloxane replica from a Si/SU-8 master. The chip is then bonded on a 170-μm-thick microscope glass slide to allow high spatial resolution live microscopy. In order to allow the cost-effective and highly repeatable production of chips with high aspect ratio (5:1) micropillars, specific design and fabrication processes were optimized. This design permits spatial confinement of the gel where cells are grown, the creation of a stable gel–liquid interface and the formation of a diffusive gradient of a chemoattractant (>48 h). The chip accomplishes both the tasks of a microfluidic bioreactor system and a cell analysis platform avoiding critical handling of the sample. The experimental fluidic tests confirm the easy handling of the chip and in particular the effectiveness of the micropillars to separate the Matrigel? from the culture media. Experimental tests of (i) the stability of the gradient, (ii) the biocompatibility and (iii) the suitability for microscopy are presented.     

Intelligent Space as a Framework for Fire Detection and Evacuation

This article discusses the application of Intelligent Space (iSpace) for fire related purposes. Both fire detection and fire evacuation are studied. It is shown that iSpace can improve current fire detection algorithms and offers a situation adaptable fire evacuation at the same time. As in future more and more factories and homes are expected to be of the iSpace concept, fire related application of iSpace is simply an addition of appropriate software and is therefore extremely easy and inexpensive.     

Photo-Fenton process as an efficient alternative to the treatment of landfill leachates

Advanced oxidation processes (AOPs), namely photo-Fenton, Fenton-like, Fenton and UV/H(2)O(2), have been investigated in the removal of organic matter and colour from landfill leachates. The leachate was characterised by high COD, low biodegradability and intense dark colour. Evaluation of COD removal as a function of the operation variables (H(2)O(2), Fe(2+), Cu(2+), UV) led to results that ranged between 30% and 77% and it was observed that the removal efficiencies decreased in the order: photo-Fenton>Fenton-like>Fenton>UV/H(2)O(2)>UV. Thus, a detailed experimental analysis was carried out to analyse the effect of the hydrogen peroxide and iron concentrations and the number of reagent additions in the photo-Fenton process, observing that: (i) the COD removal ranged from 49% to 78% depending on the H(2)O(2) dose, (ii) the total amount of organic matter removed was increased by adding the reagent in multiple steps (86%), (iii) iron concentration corresponding to a Fe(2+)/COD mass ratio=0.33 was found to be the most favourable and, (iv) after a neutralization step, the colour and residual concentrations of iron and H(2)O(2) were practically negligible in the final leachate solution.     

Composition, coagulation properties and Parmigiano-Reggiano cheese yield of Italian Brown and Italian Friesian herd milks

The authors report the results of a study aimed at the comparison of the basic chemical composition, the main protein fractions distribution, rennet coagulation properties and Parmigiano-Reggiano cheese yield of vat milk from Italian Brown and Italian Friesian herds. Parmigiano-Reggiano cheese factories which manufacture milk separately from Italian Brown herds and Italian Friesian herds were used in the study. Thirteen cheesemaking trials were performed at 10 different commercial cheese factories. The study was carried out from March to October 2003. For each cheesemaking trial in each factory, approximately 1100 kg milk from Italian Brown cows and from Italian Friesian cows were processed in parallel. The animals involved in the study came from farms with comparable management practices, size, location, number of lactation and days in milking. Each vat contained milk obtained by combining milk collected during the evening milking (partially skimmed milk by natural creaming) and the following morning milking (full-cream milk), from at least 2 dairy herds. Milk from Italian Brown cows is characterised by a higher casein content (27.1 v. 23.7 g/kg; P < or = 0.0001) than Italian Friesian cows' milk. Curd firming time (k20) of Italian Brown cows' milk was markedly lower than that of Italian Friesian cows' milk (6.6 v. 10.0 min; P < or = 0.001). This implies a higher rate of aggregation of para-casein micelles for Italian Brown cows' milk. The coagulum of Italian Brown cows' milk had better rheological properties and lower losses of fat in the cheese whey. Parmigiano-Reggiano cheese yield at 24 h was also higher for Italian Brown cows' milk, + 0.99 kg cheese for every 100 kg vat milk.     

A systematic approach to configurable functional verification of HW IP blocks at transaction level

With demand growing by the day, the complexity of electronic devices is constantly increasing. Since simulation is still the most used approach, functional verification has become one of the major bottlenecks in the design and verification flow.     

A method of production fine layout planning based on self-organising neural network clustering

Organising and optimising production in small and medium enterprises with batch production and many different products can be very difficult due to high complexity of possible solutions. The paper presents a method of fine layout planning that rearranges production resources and minimises work and material flow transfer between production cells. The method is based on self-organising map clustering which organises the production cells into groups sharing similar product properties. The proposed method improves the internal layout of each cell with respect to a material flow diagram and a from-to matrix, and fine workspace positioning also considers various restrictions on placement, specifications and types of transportation. The method is particularly suitable for improving the existing layouts. The method was applied in the Slovenian company KGL d.o.o. and promising results were achieved. A reduction by more than 40% in the total transport length with respect to the current production layout was observed.