Crystallization and preliminary X-ray diffraction analysis of recombinant chlorocatechol 1,2-dioxygenase from Pseudomonas putida

Chlorocatechol 1,2-dioxygenase from the Gram-negative bacterium Pseudomonas putida (Pp 1,2-CCD) is considered to be an important biotechnological tool owing to its ability to process a broad spectrum of organic pollutants. In the current work, the crystallization, crystallographic characterization and phasing of the recombinant Pp 1,2-CCD enzyme are described. Reddish-brown crystals were obtained in the presence of polyethylene glycol and magnesium acetate by utilizing the vapour-diffusion technique in sitting drops. Crystal dehydration was the key step in obtaining data sets, which were collected on the D03B-MX2 beamline at the CNPEM/MCT - LNLS using a MAR CCD detector. Pp 1,2-CCD crystals belonged to space group P6(1)22 and the crystallographic structure of Pp 1,2-CCD has been solved by the MR-SAD technique using Fe atoms as scattering centres and the coordinates of 3-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus (PDB entry 2boy) as the search model. The initial model, which contains three molecules in the asymmetric unit, has been refined to 3.4 A resolution.

A preliminary study of the incorparation of NPK fertilizer into chitosan nanoparticles

The use of slow release fertilizer has become a new trend to save fertilizer consumption and to minimize environmental pollution. Due to its polymeric cationic, biodegradable, bioabsorbable, and bactericidal characteristics, chitosan (CS) nanoparticle is an interesting material for use in controlled release systems. However, there are no attempts to explore the potential of chitosan nanoparticles as controlled release for NPK fertilizers. In this work chitosan nanoparticles were obtained by polymerizing methacrylic acid for the incorporation of NPK fertilizers. The interaction and stability of chitosan nanoparticle suspensions containing nitrogen (N), phosphorus (P) and potassium (K) were evaluated by FTIR spectroscopy, particle size analysis and zeta-potential. The FTIR results indicated the existence of electrostatic interactions between chitosan nanoparticles and the elements N, P and K. The stability of the CS-PMAA colloidal suspension was higher with the addition of nitrogen and potassium than with the addition of phosphorus, due to the higher anion charge from the calcium phosphate than the anion charges from the potassium chloride and urea. The mean diameter increase of the CS-PMAA nanoparticles in suspension with the addition of different compounds indicated that the elements are being aggregated on the surface of the chitosan nanoparticles.

Preliminary studies of laser-induced breakdown spectrometry for the determination of Ba, Cd, Cr and Pb in toys

The performance of laser-induced breakdown spectrometry (LIBS) for the determination of Ba, Cd, Cr and Pb in toys has been evaluated by using a Nd:YAG laser operating at 1064 nm and an Echelle spectrometer with intensified charge-coupled device detector. Samples were purchased in different cities of Sao Paulo State market and analyzed directly without sample preparation. Laser-induced breakdown spectrometry experimental conditions (number of pulses, delay time. integration time gate and pulse energy) were optimized by using a Doehlert design. Laser-induced breakdown spectrometry signals correlated reasonably well with inductively coupled plasma optical emission spectrometry (ICP OES) concentrations after microwave-assisted acid digestion of selected samples. Thermal analysis was used for polymer identification and scanning electron microscopy to Visualize differences in crater geometry of different polymers employed for toy fabrication. Results indicate that laser-induced breakdown spectrometry can be proposed as a rapid screening method for investigation of potentially toxic elements in toys. The unique application of laser-induced breakdown spectrometry for identification of contaminants in successive layers of ink and polymer is also demonstrated. (C) 2009 Elsevier B.V. All rights reserved.

DOES THE CHRONOTYPE CLASSIFICATION NEED TO BE UPDATED? PRELIMINARY FINDINGS

Traditionally, chronotype classification is based on the Morningness-Eveningness Questionnaire (MEQ). It is implicit in the classification that intermediate individuals get intermediate scores to most of the MEQ questions. However, a small group of individuals has a different pattern of answers. In some questions, they answer as ""morning-types"" and in some others they answer as ""evening-types,"" resulting in an intermediate total score. ""Evening-type"" and ""Morning-type"" answers were set as A(1) and A(4), respectively. Intermediate answers were set as A(2) and A(3). The following algorithm was applied: Bimodality Index = (Sigma A(1) x Sigma A(4))(2) - (Sigma A(2) x Sigma A(3))(2). Neither-types that had positive bimodality scores were classified as bimodal. If our hypothesis is validated by objective data, an update of chronotype classification will be required. (Author correspondence: brunojm@ymail.com)

Temporomandibular Disorder in Brazilian Patients: A Preliminary Study

The objective of the current study was to evaluate disease-related beliefs, adherence to treatment, quality of life, coping strategies and cognitive status in a group of Brazilian patients with Temporomandibular Disorder (TMD). Thirty patients were evaluated with a semi-directed interview, the Coping Strategies Inventory, and a Mini-Mental State Examination. Although half (50%) of the patients had known their diagnosis long term, 40% of the sample were not correctly following proposed treatment. All patients had a similar pattern of pain behavior related to TMD, while disease-related beliefs, quality of life and coping strategies were variable. Expectations about treatment also had significant association with treatment adherence. The findings of this study suggest that a more thorough understanding of individual differences in TMD is warranted.

The importance of scientific literacy in fostering education for sustainability: Theoretical considerations and preliminary findings from a Brazilian experience

Scientific literacy can be considered as a new demand of post-industrial society. It seems necessary in order to foster education for sustainability throughout students` academic careers. Universities striving to teach sustainability are being challenged to integrate a holistic perspective into a traditional undergraduate curriculum, which aims at specialization. This new integrative, inter- and transdisciplinary epistemological approach is necessary to cultivate autonomous citizenship, i.e., that each citizen be prepared to understand and participate in discussions about the complex contemporary issues posed by post-industrial society. This paper presents an epistemological framework to show the role of scientific literacy in fostering education for sustainability. We present a set of 26 collaborative concept maps (CCmaps) in order to illustrate an instance of theory becoming practice. During a required course for first-year undergraduate students (ACH 0011, Natural Sciences), climate change was presented and discussed in broad perspective by using CCmaps. We present students` CCmaps to show how they use concepts from quantitative and literacy disciplines to deal with the challenges posed by the need of achieving a sustainable development. (C) 2009 Elsevier Ltd. All rights reserved.

Organized Crime and Terrorism: From the Cells Towards Political Communication, A Case Study

During the first half of 2006 the city of Sao Paulo suffered three series of violent attacks against the security forces, civilians, and the government. The violent campaign also included a massive rebellion in prisons and culminated in the kidnapping of a journalist and the broadcast of a manifesto from the criminal organization PCC threatening the police and the government. Right after, the main device used to contain organized crime in the prisons was declared unconstitutional. This episode represents a prototypical example of the use of media-focused terrorism by organized crime for projection into the political communication arena.

A Cost-Benefit Analysis on Modulation Formats for 40-Gb/s Optical Communication Systems

This article discusses possible approaches for optical network capacity upgrade by considering the use of different modulation formats at 40 Gb/s. First, a performance evaluation is carried out regarding tolerance to three impairments: spectral narrowing due to filter cascading, chromatic dispersion, and self-phase modulation. Next, a cost-benefit analysis is conducted, considering the specific optoelectronic components required for the optical transmitter/receiver configuration of each format.

Chaotic communication based on the particle-in-a-box electronic circuit

A secure communication system based on the error-feedback synchronization of the electronic model of the particle-in-a-box system is proposed. This circuit allows a robust and simple electronic emulation of the mechanical behavior of the collisions of a particle inside a box, exhibiting rich chaotic behavior. The required nonlinearity to emulate the box walls is implemented in a simple way when compared with other analog electronic chaotic circuits. A master/slave synchronization of two circuits exhibiting a rich chaotic behavior demonstrates the potentiality of this system to secure communication. In this system, binary data stream information modulates the bifurcation parameter of the particle-in-a-box electronic circuit in the transmitter. In the receiver circuit, this parameter is estimated using Pecora-Carroll synchronization and error-feedback synchronization. The performance of the demodulation process is verified through the eye pattern technique applied on the recovered bit stream. During the demodulation process, the error-feedback synchronization presented better performance compared with the Pecora-Carroll synchronization. The application of the particle-in-a-box electronic circuit in a secure communication system is demonstrated.

Remote control of CNC machines using the CyberOPC communication system over public networks

During the last few years, the evolution of fieldbus and computers networks allowed the integration of different communication systems involving both production single cells and production cells, as well as other systems for business intelligence, supervision and control. Several well-adopted communication technologies exist today for public and non-public networks. Since most of the industrial applications are time-critical, the requirements of communication systems for remote control differ from common applications for computer networks accessing the Internet, such as Web, e-mail and file transfer. The solution proposed and outlined in this work is called CyberOPC. It includes the study and the implementation of a new open communication system for remote control of industrial CNC machines, making the transmission delay for time-critical control data shorter than other OPC-based solutions, and fulfilling cyber security requirements.

Friction coefficient and abrasive wear modes in ball-cratering tests conducted at constant normal force and constant pressure-Preliminary results

The micro-scale abrasive wear test by rotative ball has gained large acceptance in universities and research centers, being widely used in studies on the abrasive wear of materials. Two wear modes are usually observed in this type of test: ""rolling abrasion"" results when the abrasive particles roll on the surface of the tested specimen, while ""grooving abrasion"" is observed when the abrasive particles slide; the type of wear mode has a significant effect on the overall behaviour of a tribological system. Several works on the friction coefficient during abrasive wear tests are available in the literature, but only a few were dedicated to the friction coefficient in micro-abrasive wear tests conducted with rotating ball. Additionally, recent works have identified that results may also be affected by the change in contact pressure that occurs when tests are conducted with constant applied force. Thus, the purpose of this work is to study the relationship between friction coefficient and abrasive wear modes in ball-cratering wear tests conducted at ""constant normal force"" and ""constant pressure"". Micro-scale abrasive wear tests were conducted with a ball of AISI52100 steel and a specimen of AISIH10 tool steel. The abrasive slurry was prepared with black silicon carbide (SiC) particles (average particle size of 3 mu m) and distilled water. Two constant normal force values and two constant pressure values were selected for the tests. The tangential and normal loads were monitored throughout the tests and their ratio was calculated to provide an indication of the friction coefficient. In all cases, optical microscopy analysis of the worn craters revelated only the presence of grooving abrasion. However, a more detailed analysis conducted by SEM has indicated that different degrees of rolling abrasion have also occurred along the grooves. The results have also shown that: (i) for the selected values of constant normal force and constant pressure, the friction coefficient presents, approximately, the same range of values and (ii) loading conditions play an important role on the occurrence of rolling abrasion or grooving abrasion and, consequently, on the average value and scatter of the friction coefficient in micro-abrasive wear tests. (C) 2009 Elsevier B.V. All rights reserved.

Signals in Communication Engineering History

This paper is a study of various electric signals, which have been employed throughout the history of communication engineering in its two main landmarks: the telegraph and the telephone. The signals are presented in their time and frequency domain representations. The historical order has been followed in the presentation: wired systems, spark gap wireless, continuous wave (CW) and amplitude modulation (AM), detection by rectification, and frequency modulation (FM). The analysis of these signals is meant to lead into a better understanding of the evolution of communication technology. The material presented in this work could be used to illustrate ""Signals and Systems"" and ""Communication Systems"" courses by taking advantage of its technical as well as historical contents.

Short communication: An evaluation of the effectiveness of Lactobacillus buchneri 40788 to alter fermentation and improve the aerobic stability of corn silage in farm silos

The objective of this study was to determine if the effects of inoculation with Lactobacillus buchneri 40788 were detectable when applied to whole-plant corn stored in farm silos. Corn silage was randomly sampled from farms in Wisconsin, Minnesota, and Pennsylvania, and was untreated (n = 15) or treated with an inoculant (n = 16) containing L. buchneri 40788 alone or this organism combined with Pediococcus pentosaceus during May and June 2007. Corn silage that was removed from the silo face during the morning feeding was sampled, vacuum-packed, and heat sealed in polyethylene bags and shipped immediately to the University of Delaware for analyses. Silage samples were analyzed for dry matter (DM), nutrient composition, fermentation end-products, aerobic stability, and microbial populations. The population of L. buchneri in silages was determined using a real-time quantitative PCR method. Aerobic stability was measured as the time after exposure to air that it took for a 2 degrees C increase above an ambient temperature. The DM and concentrations of lactic and acetic acids were 35.6 and 34.5, 4.17 and 4.85, and 2.24 and 2.41%, respectively, for untreated and inoculated silages and were not different between treatments. The concentration of 1,2-propanediol was greater in inoculated silages (1.26 vs. 0.29%). Numbers of lactic acid bacteria determined on selective agar were not different between treatments. However, the numbers of L. buchneri based on measurements using real-time quantitative PCR analysis were greater and averaged 6.46 log cfu-equivalents/g compared with 4.89 log cfu-equivalent for inoculated silages. There were fewer yeasts and aerobic stability was greater in inoculated silages (4.75 log cfu/g and 74 h of stability) than in untreated silages (5.55 log cfu/g and 46 h of stability). This study supports the effectiveness of L. buchneri 40788 on dairy farms.

Short communication: Evaluation of an on-farm test to estimate somatic cell count

The objective of this study was to compare the results of an on-farm test, named Somaticell, with results of electronic cell counting and for milk somatic cell count (SCC) among readers. The Somaticell test correctly determined the SCC in fresh quarter milk samples. Correlation between Somaticell and electronic enumeration of somatic cells was 0.92 and. coefficient 0.82. Using a threshold of 205,000 cells/mL, the sensitivity and specificity for determination of intramammary infections were 91.3 and 96.0%, respectively. The SCC was greater for milk samples from which major mastitis pathogens were recovered. Minor variation among readers was observed and most likely associated with the mixing procedure. However, the final analysis indicated that this variation was not significant and did not affect the amount of samples classified as having subclinical mastitis. The on-farm test evaluated in this study showed adequate capacity of determining SCC on quarter milk samples and may be considered as an alternative for on-farm detection of subclinical mastitis.