44 research outputs found

    Methods for direct determination of mitomycin C in aqueous solutions and in urine

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    Stripping voltammetry (SV) is used to quantitatively determine concentrations of the anti-neoplastic drug mitomycin C (MMC) alone and in mixtures with 5-fluorouracil and cisplatin, both of which are used in combined chemotherapy with MMC. If the accumulation is performed at the potentials of MMC reduction (-0.35 V vs. SCE), reduced MMC is strongly adsorbed at the electrode. It is possible to prepare a MMC-modified electrode, which, after a washing step, is transferred to the background electrolyte to determine MMC by voltammetry. This procedure, which is termed transfer stripping voltammetry (TSV), helps to eliminate interferences and can be applied for a direct determination of MMC alone or in mixtures with other drugs in urine

    Achievements and Challenges in the Science of Space Weather

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    In June 2016 a group of 40 space weather scientists attended the workshop on Scientific Foundations of Space Weather at the International Space Science Institute in Bern. In this lead article to the volume based on the talks and discussions during the workshop we review some of main past achievements in the field and outline some of the challenges that the science of space weather is facing today and in the future.Peer reviewe

    On the constraints violation in forward dynamics of multibody systems

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    It is known that the dynamic equations of motion for constrained mechanical multibody systems are frequently formulated using the Newton-Euler’s approach, which is augmented with the acceleration constraint equations. This formulation results in the establishment of a mixed set of partial differential and algebraic equations, which are solved in order to predict the dynamic behavior of general multibody systems. The classical resolution of the equations of motion is highly prone to constraints violation because the position and velocity constraint equations are not fulfilled. In this work, a general and comprehensive methodology to eliminate the constraints violation at the position and velocity levels is offered. The basic idea of the described approach is to add corrective terms to the position and velocity vectors with the intent to satisfy the corresponding kinematic constraint equations. These corrective terms are evaluated as function of the Moore-Penrose generalized inverse of the Jacobian matrix and of the kinematic constraint equations. The described methodology is embedded in the standard method to solve the equations of motion based on the technique of Lagrange multipliers. Finally, the effectiveness of the described methodology is demonstrated through the dynamic modeling and simulation of different planar and spatial multibody systems. The outcomes in terms of constraints violation at the position and velocity levels, conservation of the total energy and computational efficiency are analyzed and compared with those obtained with the standard Lagrange multipliers method, the Baumgarte stabilization method, the augmented Lagrangian formulation, the index-1 augmented Lagrangian and the coordinate partitioning method.The first author expresses his gratitude to the Portuguese Foundation for Science and Technology through the PhD grant (PD/BD/114154/2016). This work has been supported by the Portuguese Foundation for Science and Technology with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio

    Soft X-ray Astronomy Payload for Use with Satellites

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    144-145General system considerations for the design of a payload for observations in soft X-ray astronomy using satellites are presented. Analysis of such a system is carried out under three broad aspects: the design of a thin window gas proportional counter system with the associated collimator, the gas control unit with its electronics and the pulse processing circuitry including the telemetry interface. Based on the requirements of sensitivity and low secondary background effects as well as the constraints imposed by spinning satellites from observational standpoint, a viable system is evolved

    Recurrent alpha-fetoprotein secreting Sertoli-Leydig cell tumor of ovary with an unusual presentation

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    Alpha-fetoprotein secreting (AFP) Sertoli-Leydig cell tumors of ovary (SLCT) are now identified as a distinct entity among the uncommon group of sex cord tumors of ovary. We report an unusual case of recurrent AFP secreting ovarian tumors and as ileocecal mesenteric cyst in a 25-year-old patient resulting in difficulty in initial diagnosis of AFP producing SLCT. Although six recurrent cases were described out of the 25 reported cases of AFP secreting SLCTs, this patient with an unusual presentation of recurrence is the second case in the literature to the best of our knowledge

    Recurrent alpha-fetoprotein secreting Sertoli-Leydig cell tumor of ovary with an unusual presentation

    No full text
    Alpha-fetoprotein secreting (AFP) Sertoli-Leydig cell tumors of ovary (SLCT) are now identified as a distinct entity among the uncommon group of sex cord tumors of ovary. We report an unusual case of recurrent AFP secreting ovarian tumors and as ileocecal mesenteric cyst in a 25-year-old patient resulting in difficulty in initial diagnosis of AFP producing SLCT. Although six recurrent cases were described out of the 25 reported cases of AFP secreting SLCTs, this patient with an unusual presentation of recurrence is the second case in the literature to the best of our knowledge

    Transglutaminase activity in equine strongyles and its potential role in growth and development

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    Transglutaminases (E.C. 2.3.3.13) are a family of Ca2+-dependent enzymes that stabilize protein structure by catalyzing the formation of isopeptide bonds. A novel form of transglutaminase has been identified and characterized that seem to play an important role in growth, development, and molting in adult and larval stages of filarial nematodes. The aim of this study was to identify the ubiquitous nature of this enzyme in other nematodes and to measure its significance to larval growth, molting, and development. For this purpose, equine Strongylus spp. were used. Activity of this enzyme was identified in extracts of larvae and adults of Strongylus vulgaris, S. edentatus, Parascaris equorum and Cylicocyclus insigne. The significance of transglutaminase in the early growth and development of Strongylus vulgaris, S. edentatus and S. equinus was tested by adding specific inhibitors, monodansylcadaverine (MDC) or cystamine (CS), to in vitro cultures of third (L3) and fourth stage larvae (L4). The viability, molting and growth of these nematode species were affected by both inhibitors. Cystamine promoted abnormal development of Strongylus edentatus L3, resulting in an aberrant expansion of the anterior end. Addition of these inhibitors to cultures of L4 also reduced growth of the three species. The results indicated that transglutaminase is present in a wide array of nematode parasites and may be important in growth and development of their larval stages

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    Not AvailableSalinity and sodicity of soils and irrigation waters is an environmental problem in the arid and semi-arid regions of the world. While this problem is natural in its genesis in the coastal regions, it occurs primarily due to anthropogenic activities in the irrigation command areas resulting from faulty-irrigation. It is the product of complex interaction of many variables, which reduce the current and the potential capability of soils to produce goods and services. In India, reports have indicated occurrence of 6.73 million ha of salt-affected soils. Vast areas are in imminent danger of turning barrenand production and productivity have simply declined due to secondary salinization. Soil salinity problems are further compounded where the ground water is highly saline and such areas by and large remain barren for want of economically feasible technological interventions thereby affecting the livelihood of the farmers because of low productivity of the existing farming practices. While both saline and sodic Vertisols, occurring in black cotton soil, can be brought under production system through diverse agro-interventions. Research conducted on saline Vertisols brought successful results involving field crops like cotton, wheat, forages including halophytic grasses, economic halophytes like Salvadara persica, seed spices like dill, medicinal and aromatic plants, agroforestry with forest and fruit species, biofuel species like Jatropha curcas, and farming system models. For sodic soils, rice and wheat systems were given priority under amendment application. These interventions along with their impacts are discussed in this chapter.Not Availabl
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