HIV heterosexual transmission to stable sexual partners of HIV-infected Brazilian hemophiliacs

Nineteen Brazilian HIV-infected hemophiliacs and their stable heterosexual sexual partners were studied with the aim of assessing the rate of HIV transmission in this at risk group. The mean length of relationship between couples was 7.4 years. The hemophiliac men were Class II (n = 6), III (n = 11) and IVa (n = 2) of the CDC classification. They had decreased CD4+ and elevated CD8+ cell numbers; five had p24 antigenemia. We found 3 HIV-infected women (15.8 percent) by routine and confirmatory tests, a prevalence similar to that seen in other countries. They were asymptomatic and had no detectable p24 antigenemia. The 3 seropositive women's partners were Class II and III-CDC, and had normal CD4+ and CD8+ values and no p24 antigenemia. All seronegative women also had normal CD4+ and CD8+ numbers, except for elevated CD8+ cells in three of them, but immune abnormalities had already been seen in some seronegative partners at high risk for HIV infection. Our results reinforce previous suggestions that heterosexual transmission to stable female partners occurs preferentially early after initiation of sexual exposure, and possibly when the transmitter had high levels of viremia and regular sexual activity.     

Gallstone ileus resulting in strong intestinal obstruction

Mechanic intestinal obstruction, caused by the passage of biliary calculus from vesicle to intestine, through fistulization, although not frequent, deserve study due to the morbi-mortality rates. Incidence in elder people explains the association with chronic degenerative diseases, increasing complexity in terms of therapy decision. Literature discusses the need and opportunity for the one or two-phase surgical attack of the cholecyst-enteric fistule, in front of the resolution on the obstructive urgency and makes reference to Gallstone Ileus as an exception for strong intestinal obstruction. The more frequent intestinal obstruction observed is when it occurs a Gallstone Ileus impacting in terms of ileocecal valve. The authors submit a Gallstone Ileus manifestation as causing strong intestinal obstruction, discussing aspects regarding diagnostic and treatment.     

Geodesics, Parallel Transport & One-Parameter Subgroups for Diffeomorphic Image Registration

Computational anatomy aims at developing models to understand the anatomical variability of organs and tissues. A widely used and validated instrument for comparing the anatomy in medical images is non-linear diffeomorphic registration which is based on a rich mathematical background. For instance, the “large deformation diffeomorphic metric mapping” (LDDMM) framework defines a Riemannian setting by providing a right invariant metric on the tangent spaces, and solves the registration problem by computing geodesics parametrized by time-varying velocity fields. A simpler alternative based on stationary velocity fields (SVF) has been proposed, using the one-parameter subgroups from Lie groups theory. In spite of its better computational efficiency, the geometrical setting of the SVF is more vague, especially regarding the relationship between one-parameter subgroups and geodesics. In this work, we detail the properties of finite dimensional Lie groups that highlight the geometric foundations of one-parameter subgroups. We show that one can define a proper underlying geometric structure (an affine manifold) based on the canonical Cartan connections, for which one-parameter subgroups and their translations are geodesics. This geometric structure is perfectly compatible with all the group operations (left, right composition and inversion), contrarily to left- (or right-) invariant Riemannian metrics. Moreover, we derive closed-form expressions for the parallel transport. Then, we investigate the generalization of such properties to infinite dimensional Lie groups. We suggest that some of the theoretical objections might actually be ruled out by the practical implementation of both the LDDMM and the SVF frameworks for image registration. This leads us to a more practical study comparing the parameterization (initial velocity field) of metric and Cartan geodesics in the specific optimization context of longitudinal and inter-subject image registration.Our experimental results suggests that stationarity is a good approximation for longitudinal deformations, while metric geodesics notably differ from stationary ones for inter-subject registration, which involves much larger and non-physical deformations. Then, we turn to the practical comparison of five parallel transport techniques along one-parameter subgroups. Our results point out the fundamental role played by the numerical implementation, which may hide the theoretical differences between the different schemes. Interestingly, even if the parallel transport generally depends on the path used, an experiment comparing the Cartan parallel transport along the one-parameter subgroup and the LDDMM (metric) geodesics from inter-subject registration suggests that our parallel transport methods are not so sensitive to the path.     

Production and characterization of membranes of recycled waste materials: Cellulose acetate,obtained from sugarcane bagasse with polystyrene from plastics cups

Membranes of cellulose acetate from sugarcane bagasse (CA), as well as blends of this cellulose acetate and polystyrene from plastic cups (CA/PS) were produced by casting utilizing dichloromethane as solvent at the concentration 12% w/w. The membranes were characterized regarding ion diffusion by dialysis and properties of pure water permeation rate, PEG rejection (utilizing an aqueous solution 1% w/v of polyethylene glycol (PEG), 45 and 80 kDa). Thermal characterization by thermogravimetric analysis and differential scanning calorimetry were also performed. The morphology of the membranes' cross‐sections was evaluated by scanning electron microscopy. The experiment of ion diffusion by dialysis showed that the ion diffusion coefficient of CA membrane is comparable to that found in the literature for membranes of commercial cellulose triacetate, 8.47 × 10^?8 cm² s^?1, while the ion diffusion coefficient of blends decreased as PS was added to the system. Regarding transport driven by pressure, CA membrane presented low rejection of PEG 80 kDa. These results showed that CA membrane could be used in a range of application comprehending the process of ultrafiltration or microfiltration. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.     

Dynamic Pareto fronts and optimal control of geometry in a problem of transient magnetic diffusion

The feasibility of dynamic multi-objective optimisation in computational electromagnetism is proved and a relevant benchmark of inverse magnetic diffusion is defined and solved. Accordingly, the optimal control of the geometry of a magnetic pole under step excitation has been proposed as a dynamic optimisation problem, characterised by two constrained objective functions that are both time- and field-dependent; the non-dominated solutions at steady state are to be determined. The benchmark has been solved numerically as a problem of transient magnetic diffusion, whereas the associated Pareto front has been identified by means of an enumerative search method in the time domain. In particular, the effect of a time-dependent energy constraint on the front at steady state has been determined. The theory of dynamic multi-objective optimisation in electromagnetism is discussed.     

Recent improvements to the ITER neutral beam system design

The ITER [1] fusion device is expected to demonstrate the feasibility of magnetically confined deuterium–tritium plasma as an energy source which might one day lead to practical power plants. Injection of energetic beams of neutral atoms (up to 1 MeV D⁰ or up to 870 keV H⁰) will be one of the primary methods used for heating the plasma, and for driving toroidal electrical current within it, the latter being essential in producing the required magnetic confinement field configuration. The design calls for each beamline to inject up to 16.5 MW of power through the duct into the tokamak, with an initial complement of two beamlines injecting parallel to the direction of the current arising from the tokamak transformer effect, and with the possibility of eventually adding a third beamline, also in the co-current direction. The general design of the beamlines has taken shape over the past 17 years [2], and is now predicated upon an RF-driven negative ion source based upon the line of sources developed by the Institute for Plasma Physics (IPP) at Garching during recent decades [3], [4], [5], and a multiple-aperture multiple-grid electrostatic accelerator derived from negative ion accelerators developed by the Japan Atomic Energy Agency (JAEA) across a similar span of time [6], [7], [8]. During the past years, the basic concept of the beam system has been further refined and developed, and assessment of suitable fabrication techniques has begun. While many design details which will be important to the installation and implementation of the ITER beams have been worked out during this time, this paper focuses upon those changes to the overall design concept which might be of general interest within the technical community.     

Potential failure mode and effects analysis for the ITER NB injector

The failure mode and effects analysis (FMEA) is a widely used analytical technique that helps in identifying and reducing the risks of failure in a system, component or process.The application of a systematic method like the FMEA was deemed necessary and adequate to support the design process of the ITER NBI (neutral beam injector). The approach adopted was to develop a FMEA at a general “system level”, focusing the study on the main functions of the system and ensuring that all the interfaces and interactions are covered among the various subsystems. The FMEA was extended to the whole NBI system taking into account the present design status. The FMEA procedure will be then applied to the detailed design phase at the component level, in particular to identify (or define) the ITER Class of Risk.Several important failure modes were evidenced, and estimates of subsystems and components reliability are now available. FMEA procedure resulted essential to identify and confirm the diagnostic systems required for protection and control, and the outcome of this analysis will represent the baseline document for the design of the NBI and NBTF integrated protection system.In the paper, rationale and background of the FMEA for ITER NBI are presented, methods employed are described and most interesting results are reported and discussed.     

A new approach to passive protection against high energy and high current breakdowns in the ITER NBI accelerator

The energy stored in the 1 MV ITER Neutral Beam Injector power supply system will exceed by far the energy stored in the existing largest NB Injectors; as a consequence, the limitation of the grid breakdown effects–grids damage and Electro Magnetic Interference emission–are critical issues. In the present ITER NBI reference design the mitigation system is based on the concept of the concentrated core snubber which, due to the large amount of stored energy, is a huge component. Furthermore, in the NBI a relatively large part of HV capacitance to ground remains downstream the core snubber, so neither the arc peak current nor the high-frequency oscillations can be effectively limited. Moreover, the concentrated core snubber is ineffective in limiting the voltage reversal caused by internal insulation fault, increasing the risk of cascade failures in components like HV bushing and transmission line. The paper proposes an alternative approach to limit the grid breakdown effects, based on the concepts of Damper Resistor- substituting the direct connection to ground of the zero-potential accelerating grid – and of Distributed Core Snubber (DCS) – installed along the whole length of the transmission lines. The DCS concept has been subjected also to experimental validation by a small scale setup supported by electrical modelling.     

Leaching and Solubility Analysis of Porcelain-Recycled Tile Residues in Clay Bricks

In this study, a porcelain tile residue was used to produce clay bricks. The residue was characterized (XRF, PSD, dilatometry, solubility, and leaching analyses) and was added to a brick paste, forming compositions that were extruded, dried, and fired at 1000°C. The fired specimens were tested [compressive strength, shrinkage, apparent density, water absorption, phase analysis (XRD), microstructure (SEM), leaching, and solubility]. The results showed that the porcelain residue was a noninert material. When added to the brick paste, the residue shows an improvement of some properties due to its alkaline content acting as a flux in the clay paste and causing the vitrification of the structure.     

Simple Preparation of Dimeric Cinchona Alkaloid Derivatives on Polystyrene Supports and a Highly Enantioselective Catalytic Heterogeneous Dimerization of Ketenes

A convenient route for the covalent immobilization of quinidine and hydroquinidine pyridazine ethers on insoluble polystyrene supports is described, which avoids the need of chromatographic purifications at any stage. The use of the heterogeneized alkaloid derivatives in the asymmetric organocatalytic dimerization of ketenes afforded high enantioselectivity values (90–97% ee) in the course of 20 reaction cycles.