The standards of care in laparoscopic surgery. The specific case of cholecystectomy

Legal suits against visceral surgeons have increased since the advent of laparoscopic surgery. The duties of physicians have not however changed with the development of laparoscopic techniques. Since the decree promulgated in 1936, physicians have a legal commitment to provide the means required for patient care. This obligation has been recalled in different court judgements and in the new deontology code. In addition, jurisprudence tends more and more towards responsibility without risk. Laparoscopic cholecystectomy is not risk-free. Although morbidity and mortality have not risen with laparoscopic procedures, the types of complications encountered have changed. Reported accidents have become more frequent. The number of suits against surgeons has also increased. Surgeons must therefore be highly prudent and diligent. Precautions concerning personnel management, the choice of material and its upkeep. Special care must be given to the peroperative pneumoperitoneum and the use of monopolar electrocoagulation. A peroperative cholangiogram should be obtained. A careful operative report is very important. The surgeon must be able to justify his competence. Finally, the surgical community should publish more results concerning the rate of complications in order to establish reference material for experts.     

Optimisation of extraction of phenolics and antioxidants from black currant leaves and buds and of stability during storage

Health benefits of a diet rich in fruits and vegetables are attributed in part to their contents of phenolics and other antioxidant compounds. In this research, the extraction of phenolics and antioxidant compounds from black currant was optimised for different plant organs. The extraction solvent affected yield: aqueous acetone was better than methanol and acetate or glycine buffer. In aqueous buffer, maximum yields of total phenolics and antioxidant activities were obtained at pH 3. Extraction from lyophilised materials yielded extracts with higher phenolic contents and antioxidant activities.     

Synthesis of N-acryloxysuccinimide copolymers by RAFT polymerization, as reactive building blocks with full control of composition and molecular weights

The reversible addition-fragmentation chain transfer (RAFT) polymerization process was used to synthesize well-defined N-acryloxysuccinimide (NAS) based copolymers, very useful reactive building blocks for various applications. Kinetic studies of RAFT copolymerization of NAS with a bi-substituted acrylamide derivative, N-acryloylmorpholine (NAM), were performed in the presence of tert-butyl dithiobenzoate (tBDB). An excellent control was reached with very high conversions (>95%), molecular weights (MW) up to 80?000 g mol⁻¹ and very narrow molecular weight distributions (MWD) (polydispersity indices, PDI<1.1), as determined by aqueous size exclusion chromatography with on-line light scattering detector (SEC/LS). In addition, the comparison of RAFT and conventional NAM/NAS free radical copolymerization indicated that the apparent reactivity ratios in RAFT are similar to the reactivity ratios determined from conventional copolymerization. An identical azeotropic composition (60/40 NAM/NAS molar ratio) was obtained providing perfectly random poly(NAM-co-NAS) copolymers with full control of composition and MW. These copolymer chains with regularly-distributed reactive functions can be integrated into more complex architectures. As an example, poly[(NAM-co-NAS)-b-NAM] block copolymers with length-varying poly(NAM) block were synthesized with a very efficient control over MW, MWD and composition.     

Implementation of a third-generation 1.1-GHz 64-bit microprocessor

This third-generation 1.1-GHz 64-bit UltraSPARC microprocessor provides 1-MB on-chip level-2 cache, 4-Gb/s off chip memory bandwidth, and a new 200 MHz JBus interface that supports one to four processors. The 87.5-million transistor chip is implemented in a seven-layer-metal copper 0.13-/spl mu/m CMOS process and dissipates 53 W at 1.3 V and 1.1 GHz.     

Signals Induced by Charge Carrier Trapping

Cryogenic germanium detectors used in dark matter searches operate at ranges of low temperature \(<\) 100 \(\mathrm {mK}\) and electric field \(\sim \) 1 \(\mathrm {V/cm}\) such that charge trapping in the bulk of the detector plays a significant role in the net charge collected following a particle interaction. It is shown that in EDELWEISS FID800 detectors, these trapped charges induce residual charge signals that perturb the measurement of the total charge, significantly degrading the energy resolution at high energy. It is also shown that, by reading out the signal on all the electrodes, it is possible to clearly identify these effects and correct the total charge measurement accordingly, resulting in a \(\sim \) 30 % improvement of the resolution at high energy. This effect is demonstrated with data. A simple analytical model based on Shockley-Ramo’s theorem is presented, whereby this effect is due to the position dependence of signals induced by trapped charges.     

Ultrasonic welding of thermoplastic composites: a numerical analysis at the mesoscopic scale relating processing parameters,flow of polymer and quality of adhesion

Ultrasonic continuous welding of thermoplastic composite plates is a very promising process of particular interest for the assembly of aeronautics large parts. Its modeling and simulation however suffers from the difficulty of accounting for the very different time scales that rule the thermo-mechanical phenomena at the level of the adhesion zone. This problem was addressed in our previous works and led to an original simulation tool presented in Levy et al. (Eur J Mech A, Solids 30(4):501–509, 2011a). In this paper, the adopted time-homogenized multiphysical modeling of the flow at the mesoscopic scale of the energy directors is first presented. Then, using the numerical software in a 2D approach, an extensive numerical parametric study of the process is presented. The phenomena allowing welding are confirmed to be an initial strain concentration in the energy director, and the formation of a flowing fold. The influence of the following process parameters are finally investigated: amplitude of vibrations, holding force of the sonotrode, thickness of the plates, radius of curvature at the tip of the director, angle of the director. Process efficiency and weld quality is evaluated through simple indicators such as the equivalent stiffness analysis, the healing degree and the risk of porosity entrapment. The present study, carried at the mesoscopic scale, provides a better understanding of the complex interactions between physical and process parameters and enables to draw important technological conclusions for the design of energy directors.     

Selective metallization of polymers using laser induced surface activation (LISA)��characterization and optimization of porous surface topography

Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was performed on the laser-machined polymer using an Alicona InfiniteFocus? microscope. Based on previous experiments, bearing area curve and its parameters are chosen to characterize the surface. In this paper, by comparison of plateable and non-plateable surfaces, and two types of plateable surface made by different lasers, it is found that the normalized bearing area curve is an effective method to characterize porous surface for the subsequent plating. The normalized parameters are available to make a quantitative analysis.     

Simulation of low rigidity part machining applied to thin-walled structures

The aim of this study is to evaluate the modelling of machining vibrations of thin-walled aluminium workpieces at high productivity rate. The use of numerical simulation is generally aimed at giving optimal cutting conditions for the precision and the surface finish needed. The proposed modelling includes all the ingredients needed for real productive machining of thin-walled parts. It has been tested with a specially designed machining test with high cutting engagement and taking into account all the phenomena involved in the dynamics of cutting. The system has been modelled using several simulation techniques. On the one hand, the milling process was modelled using a dynamic mechanistic model, with time domain simulation. On the other hand, the dynamic parameters of the system were obtained step by step by finite element analysis; thus the variation due to metal removal and the cutting edge position has been accurately taken into account. The results of the simulations were compared to those of the experiments; the discussion is based on the analysis of the cutting forces, the amplitude and the frequency of the vibrations evaluating the presence of chatter. The specific difficulties to perfect simulation of thin-walled workpiece chatter have been finely analysed.