Lymphoma: role of whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) PET in nodal staging

PURPOSE: To compare 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) in primary nodal staging of malignant lymphoma. MATERIALS AND METHODS: Sixty consecutive patients with untreated, histopathologically proved malignant lymphoma (aged 7-72 years; 33 with non-Hodgkin lymphoma, 27 with Hodgkin disease) underwent FDG PET and contrast material-enhanced CT for nodal staging. Lymph node regions identified at both CT and PET were regarded as actual locations of disease. Discordant results were verified with biopsy or clinical follow-up whenever possible. RESULTS: One hundred sixty of 740 evaluated lymph node regions were identified as diseased at both CT and PET. Of the 25 additional regions seen with PET, seven were true-positive; two, false-positive; and 16, unresolved. CT showed six additional disease manifestations; three were false-positive, and three were unresolved. Staging was changed in the four patients with the seven confirmed additional PET findings: from stage I to II in one patient and from stage II to III in three patients. Staging was changed from stage II to I in one of the three patients with false-positive CT findings. CONCLUSION: FDG PET may be more accurate for detecting nodal lymphoma than incremental CT.     

DNA-templated synthesis optimization

In chemistry, synthesis is the process in which a target compound is produced in a step-wise manner from given base compounds. A recent, promising approach for carrying out these reactions is DNA-templated synthesis, since, as opposed to more traditional methods, this approach leads to a much higher effective molarity and makes much desired (sequential) one-pot synthesis possible. With this method, compounds are tagged with DNA sequences and reactions can be controlled by bringing two compounds together via their tags. This leads to new cost optimization problems of minimizing the number of different tags or strands to be used under various conditions. We identify relevant optimization criteria, provide the first computational approach to automatically inferring DNA-templated programs, and obtain efficient optimal and near-optimal results, and also provide a brute-force integer linear programming approach for complete solutions to smaller instances.     

Reconstitution and anchoring of cytoskeleton inside giant unilamellar vesicles

Among the requirements for all life forms is the ability to self-replicate. In eukaryotic cellular systems, this division is achieved through cytokinesis, and is facilitated by the (re)arrangement and interaction of cytoskeletal proteins with lipids and other proteins localized to the plasma membrane. A fascinating challenge of modern synthetic biology is the bottom-up reconstitution of such processes for the generation of an artificial cell. One crucial step towards this goal is the functional reconstitution of the protein-anchoring machinery to facilitate cytokinesis into lipid vesicles. True to the ideal of a minimal cell-like system, we here describe the formation of an actin-based cytoskeleton within giant unilamellar vesicles (GUVs) made from porcine brain lipid extracts. We demonstrate that the actin filaments are localised and anchored to the interior walls of the GUVs through the spectrin/ankyrin proteins, and produce tightly packed actin bundles. These studies allow for the examination of cytoskeletal rearrangements within a cell-like model membrane system and represent important first steps in reconstituting the minimal machinery required for the division of an artificial cell. In addition, the study of such minimal systems can shed light on protein functions that are commonly unobservable or hidden within the overwhelming complexity of cells.     

Discovery of complex mixtures of novel long-chain quorum sensing signals in free-living and host-associated marine alphaproteobacteria

More than 100 bacterial isolates from various marine habitats were screened for AHL production by using gfp reporter constructs based on the lasR system of Pseudomonas aeruginosa and the luxR system of Vibrio fischeri. Of the 67 Alphaproteobacteria tested, most of which belonged into the so-called Roseobacter clade, 39 induced fluorescence in either one or both sensor strains up to 103-fold compared to controls. Acylated homoserine lactones were identified by GC-MS analysis and shown to have chain lengths of C8, C10, C13-C16, and C18. One or two double bonds were often present, while a keto or hydroxyl group occurred only rarely in the side chain. Most strains produced several different AHLs. C18-en-HSL and C18-dien-HSL were produced by Dinoroseobacter shibae, an aerobic anoxygenic phototrophic bacterium isolated from dinoflagellates, and are among the longest AHLs found to date. Z7-C14-en-HSL, which has previously been detected in Rhodobacter sphaeroides, was produced by Roseovarius tolerans and Jannaschia helgolandensis. This signal molecule was synthesised and shown to induce a similar response to the culture supernatant in the respective sensor strain. The widespread occurrence of quorum-sensing compounds in marine Alphaproteobacteria, both free-living strains and those associated to eukaryotic algae, points to a great importance of this signalling mechanism for the adaptation of the organisms to their widely different ecological niches.     

Intelligent backtracking in deduction systems by means of extended unification graphs

A method for unification as the basis for intelligent backtracking in deduction systems is described. This method is based on the unification graphs introduced by Cox. In this paper, unification graphs are used in an extended form such that they represent all the information which can be gained from the unification constraints, i.e., the expression to be unified, their subterms which, as a consequence, are to be unified, the number of deduction steps which cause the unification of two terms, and the term-subterm relation as far as necessary. If a unification conflict occurs from this information, the deduction steps which have led to these conflicts can be determined and reset. This is done by searching for loop-free paths or loops with certain properties in the extended unification graph, according to the type of unification conflict. Algorithms for the handling of the unification graph and for the extraction information from it are described and proved as correct.     

Threshold energy surface and frenkel pair resistivity for Cu

In-situ electrical resistivity damage-rate measurements in the high voltage electron microscope have been used to study electron irradiation induced defect production in copper single crystals at $\text{T < 10 K}$. Analysis of the directional and energy dependence yields a threshold energy surface that is significantly different from those of previous investigations: two pockets of low threshold energy centered at 〈100〉 and 〈110〉 surrounded by regions of much higher threshold energy. The corresponding damage function exhibits a plateau at 0.6 Frenkel pairs. The present results imply a Frenkel pair resistivity for Cu of (2.75 ^+0.6_?0.2) × 10^?4 Ω cm.     

Archaeological contributions of skeletal lead analysis

We developed a chemical method to quantitate lead in small skeletal specimens and used it to establish lead distribution and quantitation in modern skeletons for all age groups to standardize sampling sites. Application of the method to excavated ancient skeletal collections enabled prediction of socioeconomic status among Colonial Americans, as well as identification of lead poisoning in ancient Rome as related to lead production and in an 18th century Caribbean epidemic as related to distillation of rum. Depending upon the conditions of burial, bones may be contaminated by surrounding material. This can be a limiting factor for interpretation of lead levels, but multielement analysis and procedural modifications can permit continuing application of bone lead analysis to appropriately selected archaeological skeletal collections.     

Vakuumtechnologie für die chemische Verfahrenstechnik

Vacuum technology for the chemical industry process engineering – New developments – established principles Vacuum technology in chemical process engineering has evolved constantly over the past decades. In the beginning, liquid ring vacuum pumps were used in almost all chemical processes. But this all changed in the 1960s with the introduction of the once-through oil-lubricated rotary vane vacuum pump. The development of the dry screw vacuum pump in the 1990s represented another milestone. These are the three main types of technology available to chemical engineers today. They therefore have the choice between the traditional but proven technology of the liquid ring vacuum pump, the once-through oil-lubricated rotary vane vacuum pump and the modern screw vacuum pump that requires no operating fluids whatsoever. The decision as to which type is the right choice should be left to a proven vacuum specialist. Each and every critical parameter – from the process conditions, process gases and integration into process control right through to assessing the economic efficiency, safety and reliability of the future vacuum generation – must be taken into consideration.     

Modelling speech emotion recognition using logistic regression and decision trees

Speech emotion recognition has been one of the interesting issues in speech processing over the last few decades. Modelling of the emotion recognition process serves to understand as well as assess the performance of the system. This paper compares two different models for speech emotion recognition using vocal tract features namely, the first four formants and their respective bandwidths. The first model is based on a decision tree and the second one employs logistic regression. Whereas the decision tree models are based on machine learning, regression models have a strong statistical basis. The logistic regression models and the decision tree models developed in this work for several cases of binary classifications were validated by speech emotion recognition experiments conducted on a Malayalam emotional speech database of 2800 speech files, collected from ten speakers. The models are not only simple, but also meaningful since they indicate the contribution of each predictor. The experimental results indicate that speech emotion recognition using formants and bandwidths was better modelled using decision trees, which gave higher emotion recognition accuracies compared to logistic regression. The highest accuracy obtained using decision tree was 93.63%, for the classification of positive valence emotional speech as surprised or happy, using seven features. When using logistic regression for the same binary classification, the highest accuracy obtained was 73%, with eight features.