Micro-Scale Restraint Methodology for Humidity Induced Swelling Investigated by Phase Contrast X-Ray Tomography

A new methodology for restraining the swelling of spruce wood samples in the micrometre range is developed and presented. We show that the restraining device successfully prevents the free swelling of wood during moisture adsorption, thus modifying significantly the anisotropy of swelling and provoking the intended collapse and large deformations of the wood cells at the edges of the sample in contact with the restraining device. The device consists in a slotted cube designed to restrain swelling and is made of PMMA manufactured by laser ablation. The sample undergoing the restraining experiment is imaged with high-resolution synchrotron radiation phase contrast X-Ray Tomographic Microscopy. The deformation of the restraining device itself is only approximately 2μm with respect to a 500μm width in cubes containing latewood samples and half of that in the case of cubes containing earlywood

One ligand, two regulators and three binding sites: How KDPG controls primary carbon metabolism in Pseudomonas

Effective regulation of primary carbon metabolism is critically important for bacteria to successfully adapt to different environments. We have identified an uncharacterised transcriptional regulator; RccR, that controls this process in response to carbon source availability. Disruption of rccR in the plant-associated microbe Pseudomonas fluorescens inhibits growth in defined media, and compromises its ability to colonise the wheat rhizosphere. Structurally, RccR is almost identical to the Entner-Doudoroff (ED) pathway regulator HexR, and both proteins are controlled by the same ED-intermediate; 2-keto-3-deoxy-6-phosphogluconate (KDPG). Despite these similarities, HexR and RccR control entirely different aspects of primary metabolism, with RccR regulating pyruvate metabolism (aceEF), the glyoxylate shunt (aceA, glcB, pntAA) and gluconeogenesis (pckA, gap). RccR displays complex and unusual regulatory behaviour; switching repression between the pyruvate metabolism and glyoxylate shunt/gluconeogenesis loci depending on the available carbon source. This regulatory complexity is enabled by two distinct pseudo-palindromic binding sites, differing only in the length of their linker regions, with KDPG binding increasing affinity for the 28 bp aceA binding site but decreasing affinity for the 15 bp aceE site. Thus, RccR is able to simultaneously suppress and activate gene expression in response to carbon source availability. Together, the RccR and HexR regulators enable the rapid coordination of multiple aspects of primary carbon metabolism, in response to levels of a single key intermediate

Cancer therapy and cardiotoxicity: The need of serial Doppler echocardiography

Cancer therapy has shown terrific progress leading to important reduction of morbidity and mortality of several kinds of cancer. The therapeutic management of oncologic patients includes combinations of drugs, radiation therapy and surgery. Many of these therapies produce adverse cardiovascular complications which may negatively affect both the quality of life and the prognosis. For several years the most common noninvasive method of monitoring cardiotoxicity has been represented by radionuclide ventriculography while other tests as effort EKG and stress myocardial perfusion imaging may detect ischemic complications, and 24-hour Holter monitoring unmask suspected arrhythmias. Also biomarkers such as troponine I and T and B-type natriuretic peptide may be useful for early detection of cardiotoxicity. Today, the widely used non-invasive method of monitoring cardiotoxicity of cancer therapy is, however, represented by Doppler-echocardiography which allows to identify the main forms of cardiac complications of cancer therapy: left ventricular (systolic and diastolic) dysfunction, valve heart disease, pericarditis and pericardial effusion, carotid artery lesions. Advanced ultrasound tools, as Integrated Backscatter and Tissue Doppler, but also simple ultrasound detection of "lung comet" on the anterior and lateral chest can be helpful for early, subclinical diagnosis of cardiac involvement. Serial Doppler echocardiographic evaluation has to be encouraged in the oncologic patients, before, during and even late after therapy completion. This is crucial when using anthracyclines, which have early but, most importantly, late, cumulative cardiac toxicity. The echocardiographic monitoring appears even indispensable after radiation therapy, whose detrimental effects may appear several years after the end of irradiation

The effect of autonomy, training opportunities, age and salaries on job satisfaction in the South East Asian retail petroleum industry

South East Asian petroleum retailers are under considerable pressure to improve service quality by reducing turnover. An empirical methodology from this industry determined the extent to which job characteristics, training opportunities, age and salary influenced the level of job satisfaction, an indicator of turnover. Responses are reported on a random sample of 165 site employees (a 68% response rate) of a Singaporean retail petroleum firm. A restricted multivariate regression model of autonomy and training opportunities explained the majority (35.4%) of the variability of job satisfaction. Age did not moderate these relationships, except for employees >21 years of age, who reported enhanced job satisfaction with additional salary. Human Capital theory, Life Cycle theory and Job Enrichment theory are invoked and explored in the context of these findings in the South East Asian retail petroleum industry. In the South East Asian retail petroleum industry, jobs providing employees with the opportunity to undertake a variety of tasks that enhanced the experienced meaningfulness of work are likely to promote job satisfaction, reduce turnover and increase the quality of service

SREB, a GATA Transcription Factor That Directs Disparate Fates in Blastomyces dermatitidis Including Morphogenesis and Siderophore Biosynthesis

Blastomyces dermatitidis belongs to a group of human pathogenic fungi that exhibit thermal dimorphism. At 22°C, these fungi grow as mold that produce conidia or infectious particles, whereas at 37°C they convert to budding yeast. The ability to switch between these forms is essential for virulence in mammals and may enable these organisms to survive in the soil. To identify genes that regulate this phase transition, we used Agrobacterium tumefaciens to mutagenize B. dermatitidis conidia and screened transformants for defects in morphogenesis. We found that the GATA transcription factor SREB governs multiple fates in B. dermatitidis: phase transition from yeast to mold, cell growth at 22°C, and biosynthesis of siderophores under iron-replete conditions. Insertional and null mutants fail to convert to mold, do not accumulate significant biomass at 22°C, and are unable to suppress siderophore biosynthesis under iron-replete conditions. The defect in morphogenesis in the SREB mutant was independent of exogenous iron concentration, suggesting that SREB promotes the phase transition by altering the expression of genes that are unrelated to siderophore biosynthesis. Using bioinformatic and gene expression analyses, we identified candidate genes with upstream GATA sites whose expression is altered in the null mutant that may be direct or indirect targets of SREB and promote the phase transition. We conclude that SREB functions as a transcription factor that promotes morphogenesis and regulates siderophore biosynthesis. To our knowledge, this is the first gene identified that promotes the conversion from yeast to mold in the dimorphic fungi, and may shed light on environmental persistence of these pathogens

Electrical conductivity of strontium bismuth titanate under controlled oxygen partial pressure

The electrical conductivity of SrBi4Ti4O15 (SBT) has been measured under controlled oxygen partial pressure. Both acceptor and donor doping effects were studied using de conductivity and impedance measurements. In addition to the ceramic samples with random grain orientation, grain oriented samples were prepared by hot forging. It has been shown that the conductivity of SBT is electronic p type in air at low temperature and it is n type at high temperature (greater than or equal to 700 degrees) up to 1 atm pO(2). The conductivity is increased by Mn doping and decreased by Nb doping at low temperatures (less than or equal to 220 degrees C) and decreased by Mn coping and increased by Nb doping at high temperatures (700-1000 degrees C). The slope of the conductivity versus pO(2) curve is significantly decreased by Mn coping above 700 degrees C in the pO(2) range from 1 atm to 10(-5) atm. (C) 1999 Elsevier Science Limited. All rights reserved

Finding socio-Textual associations among locations

An increasing amount of user-generated content on the Web is geotagged. This often results in the formation of user trails, e.g., sequences of photos, check-ins, or text messages, that users generate while visiting various locations. In this paper, we introduce and study the problem of identifying sets of locations that are strongly associated under social and textual criteria. We say that a location set is associated with a set of keywords if there exists a user with posts around these locations whose textual descriptions cover all keywords. We measure the strength of this association by the number of users with posts that support it. Although the problem reminisces frequent itemset mining, we show that our support measure does not satisfy the necessary anti-monotonicity property, which is used to effectively prune the search space. Nonetheless, by studying the characteristics of the support measure, we are able to devise an efficient approach. We present a basic and two optimized algorithms, exploiting an inverted or a spatio-textual index to increase efficiency. Finally, we conduct an experimental evaluation using geotagged Flickr photos in three major cities. From a qualitative perspective, the results indicate that the introduced type of query returns meaningful and interesting location sets, which are not discovered by other existing approaches. Furthermore, the proposed optimizations and the use of appropriate indexes significantly reduce computation time

Quantitative calorimetric investigation of fed-batch cultures of Bacillus sphaericus 1593M

For many years, calorimetry has been recognized as a powerful and universal tool for monitoring chem. and biol. processes. A lab.-scale reaction calorimeter (RC1, Mettler-Toledo), initially developed for chem. reaction studies with a sensitivity of 100-150 mW/l, has been improved to enable the monitoring of very low heat prodn. rates (<10 mW/l). A major limitation to successful process control, has been the inability to achieve real-time quant. calorimetry. This is in part due to the operating principle of the RC1, in which the measured heat signal is calcd. from the temp. difference between the reaction mass and the jacket oil and the heat transfer coeff. (UA). The latter frequently varies during a reaction, particularly a bioreaction, due to changes in vol., viscosity and cell d., and is difficult to det. accurately during the process.In the present study, this problem has been solved by a tech. modification to the reactor vessel of the RC1. This involves forcing the heat transfer to occur through a well defined and const. area through the creation of a large resistance to heat transfer in the upper part of the reactor vessel. This was achieved by creating an air gap between the reactor contents and the reactor wall through the insertion of a PTFE sleeve. Control expts. undertaken with this modified system, in the absence of any reaction, showed that UA remained const. for vol. changes as large as 50% of the working vol. Similarly, a simulated fed-batch expt. with monitoring of the stirring power, showed that the baseline heat signal could be accurately and quant. cor. for large dynamic variations of the vol.Using monitoring of the oxygen uptake rate as a ref., this modified system was validated by application to fed-batch cultures of Bacillus sphaericus 1593M. This strictly aerobic bacterium produces parasporal insecticidal crystal proteins which are toxic to mosquito larvae. In these fed-batch cultures, the nutrient feed was controlled using measurement of the metabolic heat release, since the latter is proportional to the substrate uptake rates for a given metabolic state. A culture, composed of two repetitive fed-batch cycles followed by a batch cycle, demonstrated that real-time and quant. signals could be obtained, even for highly dynamic processes in which the vol. and agitation rate may vary significantly and where quick repetitive inoculations can be made. The result of this work is a modified RC1 (or Bio-RC1) which is as easy to use as any conventional bioreactor yet has the unique feature of being able to provide an accurate measurement of the energy dissipated as heat in chem. or biol. processes, over a wide range of operating conditions. [on SciFinder (R)