Model-driven engineering for mobile robotic systems: a systematic mapping study

Software and Systems Modeling - Mobile robots operate in various environments (e.g. aquatic, aerial, or terrestrial), they come in many diverse shapes and they are increasingly becoming parts of...     

2-Phenyloxazole-4-carboxamide as a Scaffold for Selective Inhibition of Human Monoamine Oxidase B

A series of 2-phenyloxazoles bearing an amide group at position 4 were designed and synthesized for evaluation as potential inhibitors of human recombinant monoamine oxidases (hrMAOs). Results of kinetics experiments demonstrated that all compounds behave as competitive MAO inhibitors, with good selectivity toward the MAO-B isoform. The most potent and selective derivatives are characterized by inhibition constant (K_i) values in the sub-micromolar range and a good selectivity index (K_{i MAO-A}/K_{i MAO-B}>50). Some derivatives were also found to be able to inhibit MAO activity in nerve growth factor (NGF)-differentiated PC12 cells, taken as a model of neuronal cells. In particular, 2-(2-hydroxyphenyl)-N-phenyloxazole-4-carboxamide (compound 4 a ) may be a promising new scaffold, exerting the highest selectivity and inhibitory effect toward MAOs in NGF-differentiated PC12 cell lysates, without compromising cell viability. Molecular docking analysis allowed a rationalization of the experimentally observed binding affinity and selectivity.     

Ultrasonographic semiology of biliary prostheses

Pigeon hemoglobin has eight reactive sulphydryl groups per (tetramer) molecule, as determined by Boyer titration with p-chloromercuribenzoate. However, only four of these are titratable with 5,5'-dithiobis(2-nitrobenzoate) under the same experimental conditions. The time course of the reaction of pigeon hemoglobin with 5,5'-dithiobis(2-nitrobenzoate) is biphasic. In the pH range 6-9, the fast phase is between one and two orders of magnitude faster than the slow phase. For the fast phase, kapp, the apparent second-order rate constant, increases monotonously with pH. Quantitative analysis reveals that the reaction of the sulphydryl group responsible for this phase is coupled to the ionization of two groups with pKa values of 6.15 +/- 0.1 and 8.5 +/- 0.1. These pKa values are assigned to HisHC3(146) beta and to the CysF9(93) beta sulphydryl group, respectively. For the slow phase the kapp vs. pH profiles are bowl-shaped. Analysis reveals that the reaction of the sulphydryl group to which this phase may be attributed is coupled to the ionization of two groups with mean pKa values of 6.53 +/- 0.1 and 8.25 +/- 0.1. Examination of the structure of hemoglobin allows us to assign these values to HisG19(117) beta and CysB5(23) beta, respectively. The CysB5(23) beta sulphydryl is in the region of the molecule where amino acid substitutions have been found to give rise to significant changes in the oxygen affinity of hemoglobin [Huang et al. (1990), Biochemistry 29, 7020-7023].     

In-utero transplantation of parental CD34 haematopoietic progenitor cells in a patient with X-linked severe combined immunodeficiency (SCIDXI)

BACKGROUND: X-linked severe combined immunodeficiency (SCIDXI) is an inherited immune defect which leads to death in infancy from severe infections. The defect is caused by mutations of the IL-2RG gene that encodes for the common gamma chain shared by several cytokine receptors. The disease is characterised by lack of T and NK cells with normal numbers of B cells. SCIDXI can be cured by bone marrow transplantation (BMT) or prevented by abortion after prenatal diagnosis. METHODS: A male fetus was diagnosed as having SCIDXI by molecular, immunophenotypic, and functional analyses. The fetus was injected intraperitoneally under ultrasound guidance with CD34 haematopoietic progenitor cells purified from paternal bone marrow and T-cell depleted by E rosetting. Chimerism analysis was by HLA-DQ alpha typing and gamma-chain staining on cord blood. FINDINGS: A healthy 3.6 kg boy was delivered by caesarean section at 38 weeks of gestation with no clinical or laboratory signs of graft-versus-host disease. Engraftment of donor-derived CD2 cells was found at birth. At 3.5 months of age the infant is well and his T-cell counts and function are normal. INTERPRETATION: In-utero transplantation of haematopoietic progenitor cells allowed immune reconstitution of a fetus with SCIDXI and may be an alternative to elective abortion. Our report should encourage applications of this method to other inherited disorders curable by BMT.     

Plasma mevalonate concentrations in uremic patients

Mevalonic acid (mevalonate or MVA), is an obligate precursor in the biosynthetic pathway of cholesterol. It is partially metabolized by the kidneys and its plasma concentrations are an index of endogenous cholesterol synthesis. The aim of the present study was to evaluate plasma MVA concentrations in uremic patients with different degrees of chronic renal failure (CRF; group A), and the effects of a single hemodialysis treatment on plasma MVA in a group of patients with end-stage renal disease (ESRD; group B). CRF patients exhibited a higher mean basal mevalonate concentration (13.3 +/- 6.5 ng/ml) than control subjects (4.68 +/- 1.32 ng/ml; P < 0.001). A statistically significant direct correlation was evident in CRF patients between mevalonate and creatinine plasma levels (r = 0.86; P < 0.001). A single hemodialysis treatment was associated with a significant reduction of plasma mevalonate concentrations four hours after the hemodialysis session (-57%; P < 0.001) and an increase up to the basal values 24 hours after the end of the treatment. In conclusion, our results demonstrated: (i) higher plasma MVA concentrations in patients with decreased renal function; (ii) a direct relationship between plasma MVA levels and the degree of kidney failure as expressed by creatinine plasma concentrations; and (iii) a clear cut reduction of elevated plasma MVA levels after a single hemodialysis treatment.     

On the cramer-rao bound for carrier frequency estimation in the presence of phase noise

We consider the carrier frequency offset estimation in a digital burst-mode satellite transmission affected by phase noise. The corresponding Cramer-Rao lower bound is analyzed for linear modulations under a Wiener phase noise model and in the hypothesis of knowledge of the transmitted data. Even if we resort to a Monte Carlo average, from a computational point of view the evaluation of the Cramer-Rao bound is very hard. We introduce a simple but very accurate approximation that allows to carry out this task in a very easy way. As it will be shown, the presence of the phase noise produces a remarkable performance degradation of. the frequency estimation accuracy. In addition, we provide asymptotic expressions of the Cramer-Rao bound, from which the effect of the phase noise and the dependence on the system parameters of the frequency offset estimation accuracy clearly result. Finally, as a by-product of our derivations and approximations, we derive a couple of estimators specifically tailored for the phase noise channel that will be compared with the classical Rife and Boorstyn algorithm, gaining in this way some important hints on the estimators to be used in this scenario     

Experimental and theoretical investigation on unburned coal char burnout in a pilot-scale rotary kiln

Oxidation reactivity studies are imperative for improving carbon re-burn technologies and valuing the heat content of unburned carbon within coal combustion ashes. Non-isothermal, thermal gravimetric analysis (TGA) was used to examine the oxidation kinetics of unburned carbon in coal combustion fly ashes having different particle size distributions; TGA results were related to combustion efficiencies as measured in a bench-scale rotary kiln. The activation energy and pre-exponential factor were determined for the chemically-controlled reaction regime; the transition temperatures between chemically-controlled and partially diffusion-controlled combustion regimes were obtained for unburned carbon particles of different sizes. After the oxidation reaction rates were evaluated, the residence time distribution (RTD) of fly ashes in the rotary kiln were experimentally measured and the mean residence times related to process parameters, including the rotating velocity and kiln inclination. By comparing these results with an advective-dispersive model, the axial dispersion coefficient of fly ashes was determined. The reaction rates obtained by thermal analyses and the RTDs were used to predict combustion efficiencies within the kiln and oxidation conditions of unburned carbon using various processing options.