Miniaturized devices for isothermal DNA amplification addressing DNA diagnostics

Microfluidics is an emerging technology enabling the development of lab-on-a-chip systems for clinical diagnostics, drug discovery and screening, food safety and environmental analysis. Currently, available nucleic acid diagnostic tests take advantage of polymerase chain reaction that allows exponential amplification of portions of nucleic acid sequences that can be used as indicators for the identification of various diseases. At the same time, isothermal methods for DNA amplification are being developed and are preferred for their simplified protocols and the elimination of thermocycling. Here, we present a low-cost and fast DNA amplification device for isothermal helicase dependent amplification implemented in the detection of mutations related to breast cancer as well as the detection of Salmonella pathogens. The device is fabricated by mass production amenable technologies on printed circuit board substrates, where copper facilitates the incorporation of on-chip microheaters, defining the thermal zone necessary for isothermal amplification methods.     

A Trainable System for Object Detection

This paper presents a general, trainable system for object detection in unconstrained, cluttered scenes. The system derives much of its power from a representation that describes an object class in terms of an overcomplete dictionary of local, oriented, multiscale intensity differences between adjacent regions, efficiently computable as a Haar wavelet transform. This example-based learning approach implicitly derives a model of an object class by training a support vector machine classifier using a large set of positive and negative examples. We present results on face, people, and car detection tasks using the same architecture. In addition, we quantify how the representation affects detection performance by considering several alternate representations including pixels and principal components. We also describe a real-time application of our person detection system as part of a driver assistance system.     

Myomectomy during pregnancy and caesarean section

Myomectomy was performed on a 31 year old primigravida during the 15th week of pregnancy due to a large myoma which was 23 cm in diameter. At the 39th week of pregnancy, during the Caesarean section, eight fibroids obstructing the lower part of the uterus were removed. There were no maternal or fetal complications.     

Low-Temperature Synthesis and Thermoelectric Properties of n-Type PbTe

n-Type PbTe compounds were synthesized at temperatures as low as 430°C. After synthesis, the materials were ground, cold pressed, and sintered at 600°C. The effect of this low-temperature synthesis on the structural features and thermoelectric properties of as-prepared and PbI₂-doped materials was investigated for the first time. The Seebeck coefficient, and electrical and thermal conductivity were measured in the temperature range 2 K ≤ T ≤  610 K. The results show that all materials exhibit n-type conduction and the thermoelectric properties are improved by doping. ZT values reach 0.5 at 610 K, and the discrepancies with the literature are discussed.     

Cutoff frequencies in optical fibers of arbitrary refractive index profile using the resonance technique

We present a very simple and accurate numerical method for calculating the cutoff frequencies of arbitrary refractive index profile optical fibers, including discrete numerical data from profile measurements. From Maxwell's equations we derive a transmission line equivalent circuit for any mode of an optical fiber which is cutoff frequency dependent. The problem of finding the cutoff frequency of a mode is transformed into finding the resonance frequency of the equivalent circuit. The algorithm uses no Bessel or other complicated functions and could be implemented on small microcomputers.     

Tailoring the release rates of fluconazole using solid dispersions in polymer blends

Formulations of the drug Fluconazole with different release characteristics were prepared by dispersing the active pharmaceutical ingredient (API) in various polymeric carriers, and especially in polymer blends. Fluconazole was tested as a model drug with low solubility in water. First solid dispersions in pure polymers were studied. Use of pure polyvinylpyrrolidone (PVP) as carrier even for high drug load (30 wt%) resulted in rapid release. The drug release rates decreased by increasing the API content. The dissolution rate enhancement was attributed to drug amorphization, particle size reduction, and possible improvement of the drug wetting characteristics. Hydroxypropyl methylcellulose (HPMC) gave solid dispersions, from which the release rates of the drug varied from immediate to sustaining. As the drug amount increased, the rates became higher. Similar behavior also was found when Chitosan was used as carrier, with much more controlled rates close to those for sustained release. These differences were mainly attributed to the limited solubility and swelling of HPMC and Chitosan in aquatic media. To study the effectiveness of polymer blends in adjusting the release rates of the drug, solid dispersions in PVP/HPMC and PVP/Chitosan miscible blends were studied. The release rates of Fluconazole were adequately adjusted by differentiating the weight ratio of the polymers in the blends. PVP/HPMC blends with high PVP content can be used for immediate release formulations but PVP/Chitosan blends are inappropriate for such formulations and can only be used for controlled release.     

Optimal maintenance planning and crew allocation for multipurpose batch plants

A mathematical programming approach to optimize process plant performance subject to equipment failure is presented. The optimal production planning and scheduling in multipurpose process plants involves the efficient utilization of assets and resources to produce a number of products so as to satisfy market demands while optimizing a performance criterion. However, the degree of utilization of process plant components, within the time horizon of operation, critically depends on the level of equipment availability. The interactions between production and maintenance planning as well as the necessary links to quantify the strong interactions between them are studied. The preventive maintenance planning and crew allocation problem are used to demonstrate the effectiveness of the proposed approach. The overall problem is first formulated as an optimal control problem by integrating an aggregate production planning model with a continuous time Markov chain maintenance model. The resulting problem is then transformed into a mixed-integer linear programming model by using an Euler discretization scheme and appropriate linearizations of bilinear terms. Finally, extensions to include design aspects are also discussed. The applicability of the proposed approach is demonstrated by a number of illustrative examples.     

Heavy metal sorption by calcium alginate beads from Laminaria digitata

Alginate with a high M/G ratio, extracted from Laminaria digitata, was evaluated for Cu(2+), Cd(2+) and Pb(2+) sorption in acidic solutions, in the form of calcium cross-linked beads. The high M/G ratio of alginate extracted from this algal species is most likely the determining factor for the increased adsorption capacity of the investigated metals, indicating that the mannuronic acid is responsible for the ion exchange mechanism. The data obtained from the batch experiments have been interpreted with Langmuir, Freundlich and Sips models. The Sips equation provided the best fit with the experimental results, indicating sorption sites heterogeneity for the material. The pH was found to have a significant effect on the process, with sorption capacity reaching a maximum at pH 4.5, indicating a competition mechanism between H(+) and metal ions. Kinetic experiments were performed at the optimum pH. For the interpretation of the kinetic experiments the Linear Adsorption Model was employed and diffusion coefficients were determined. The model fits the experimental data at higher concentrations, where the adsorbed quantity remains almost constant. Finally, a simplified expression of the batch kinetic adsorption model was employed. The model, predicts adequately, not only the diffusivity values, but also the concentration profiles inside the spherical particles.     

Rupture of an abdominal aortic aneurysm following acute descending thoracic aortic dissection. Case report

The coexistence of an abdominal aortic aneurysm and an acute aortic dissection seems to be rare and only a few reports are to be found in the literature. We report a case of a patient with acute aortic dissection of the descending thoracic aorta that caused rupture of a pre-existing abdominal aortic aneurysm. The literature is also thoroughly reviewed.     

Extensive apoptosis of bone marrow cells as evaluated by the in situ end-labelling (ISEL) technique may be the basis for ineffective haematopoiesis in patients with myelodysplastic syndromes

By using data from the Bremer Adolescent Study, this report presents findings on the frequency, comorbidity, and psychosocial impairment of panic disorder and panic attacks among 1,035 adolescents. The adolescents were randomly selected from 36 schools in the province of Bremen, Germany. Panic disorder and other psychiatric disorders were coded based on DSM-IV criteria using the computerized-assisted personal interview of the Munich version of the Composite International Diagnostic Interview. Panic disorder occurred rather rare, with only 0.5% of all the adolescents met the DSM-IV criteria for this disorder sometimes in their live. Panic attack occurred more frequently, with 18% of the adolescents reported having had at least one panic attack. Slightly more girls than boys had panic attack and panic disorder. The occurrence of panic attack and panic disorder were the greatest among the 14-15 year olds. The experience of having a panic attack was associated with a number of problems, the most frequent being avoiding the situation for fear of having another attack. Four most common symptoms associated with a panic attack were that of palpitations, trembling/shaking, nausea or abdominal distress, and chills or hot flushes. Panic disorder comorbid highly with other psychiatric disorder covered in our study, especially with that of major depression. Among those with a panic disorder, about 40% of them were severely impaired during the worst episode of their illness. Only one out of five adolescents with panic disorder sought professional help for emotional and psychiatric problems. The implication of our findings for research and clinical practice are discussed.