Fitting a woven cloth model to a curved surface: dart insertion

If a woven cloth composite “ply” cannot fit a surface exactly, “darts” must be cut. Algorithms that define these darts for a CAD system resolve anomalies in the 3D ply     

Comparison of "catheter" and conventional arthroscopy in the diagnosis of knee derangements

The diagnostic efficiency of the Optical Catheter System (OCS), which uses a 1.7-mm arthroscope, was compared with that of conventional arthroscopy in 50 patients with various knee derangements in standard arthroscopic conditions. Correct diagnoses were obtained with the OCS in 98% of anterior cruciate ligament derangements--92%-98% of those involving the medial and lateral meniscus, respectively--and 96% of cartilage disorders. No false-positives were noted for anterior cruciate ligament and meniscus injuries. False-negatives were caused by abundant intraarticular bleeding (no tourniquet was applied) and peripheral meniscus tears and false-positives by synovial superposition resulting in a mistaken diagnosis of patellar chondromalacia. The OCS proved a good diagnostic tool. Its employment, especially in an outpatient setting, should be restricted to a small number of patients and entrusted to expert arthroscopists.     

Two family outbreaks of Chlamydia pneumoniae infection

During autumn 1992, we observed two unrelated family outbreaks of Chlamydia pneumoniae infection. Family A consisted of grandmother (aged 77 yrs), father (aged 41 yrs), mother (aged 38 yrs), daughter (aged 10 yrs), and two sons (aged 6 yrs and 3 months, respectively). The grandmother and daughter suffered from pneumonia, father from pharyngitis and bronchitis and the older son from mild bronchitis. No symptoms were recorded in the mother and younger son. Symptomatic subjects showed a fourfold increase in immunoglobulin G (IgG) titre for Chlamydia pneumoniae, determined by a microimmunofluorescence test with specific antigen (TW-183). Other serological studies against Mycoplasma pneumonia, Legionella pneumophila, influenza virus type A and B, adenovirus and respiratory syncytial virus (RSV) were negative. Sputum culture gave a positive result for Haemophilus influenzae, colony forming units (cfu) = 10(4).ml-1 in the grandmother. No serum positivity was recorded in the mother and younger son, who remained asymptomatic. All symptomatic patients were successfully treated with macrolides. Family B consisted of mother (aged 63 yrs) and daughter (aged 36 yrs). Both suffered from Chlamydia pneumoniae pneumonia. Diagnosis was made by means of serological microimmunofluorescence test, and direct identification using an indirect immunofluorescence test on pharyngeal swab. Sputum culture and other serological tests remained negative. Both patients were successfully treated with macrolides. These observations emphasize the relevance of Chlamydia pneumoniae in family cluster respiratory infections.     

Optical properties of high-density dispersions of particles: application to intralipid solutions

We propose to study the scattering properties of dense distributions of spherical scatterers by resorting to an iterative solution of the Foldy-Twersky equation for the propagation of the coherent field. As a result of the first step of the iterative procedure, the host medium is substituted by an effective medium of complex refractive index to account for the multiple-scattering processes that occur among the particles. Although we truncate the above-mentioned iterative procedure to the second step, the results of our calculations are in excellent agreement with previous experimental results of Zaccanti et al. ("Measurement of optical properties of high-density media," to be published in Applied Optics) for the scattering coefficient of Intralipid solutions up to a volume density of 15% and show a limited disagreement at a volume density of 22%.     

Electroactive Ionic Soft Actuators with Monolithically Integrated Gold Nanocomposite Electrodes

Electroactive ionic gel/metal nanocomposites are produced by implanting supersonically accelerated neutral gold nanoparticles into a novel chemically crosslinked ion conductive soft polymer. The ionic gel consists of chemically crosslinked poly(acrylic acid) and polyacrylonitrile networks, blended with halloysite nanoclays and imidazolium‐based ionic liquid. The material exhibits mechanical properties similar to that of elastomers (Young's modulus ≈ 0.35 MPa) together with high ionic conductivity. The fabrication of thin (≈100 nm thick) nanostructured compliant electrodes by means of supersonic cluster beam implantation (SCBI) does not significantly alter the mechanical properties of the soft polymer and provides controlled electrical properties and large surface area for ions storage. SCBI is cost effective and suitable for the scaleup manufacturing of electroactive soft actuators. This study reports the high‐strain electromechanical actuation performance of the novel ionic gel/metal nanocomposites in a low‐voltage regime (from 0.1 to 5 V), with long‐term stability up to 76 000 cycles with no electrode delamination or deterioration. The observed behavior is due to both the intrinsic features of the ionic gel (elasticity and ionic transport capability) and the electrical and morphological features of the electrodes, providing low specific resistance (<100 Ω cm^?2), high electrochemical capacitance (≈mF g^?1), and minimal mechanical stress at the polymer/metal composite interface upon deformation.     

Estimation of the linewidth enhancement factor for a PbCdS diodelaser

An estimation of the linewidth enhancement factor α for a PbCdS diode laser is reported. The measurement method, which is an extension of an earlier procedure involving studies of mode spectra, was devised particularly for this lead-salt diode laser of very low output power. A quite low α of 1.3 was obtained, well below the values for other types of diode lasers