Particle systems have many applications, with the most popular being to produce special effects in video games and films. To permit particle systems to be created quickly and easily, Particle System Interfaces (PSIs) have been developed. A PSI is a piece of software designed to perform common tasks related to particle systems for clients, while providing them with a set of parameters whose values can be adjusted to create different particle systems. Most PSIs are inflexible, and when clients require functionality that is not supported by the PSI they are using, they are forced to either find another PSI that meets their requirements or, more commonly, create their own particle system or PSI from scratch. This paper presents three original contributions. First, it identifies 18 features that a PSI should provide in order to be capable of creating diverse effects. If these features are implemented in a PSI, clients will be more likely to be able to accomplish all desired effects related to particle systems with one PSI. Secondly, it introduces a novel use of events to determine, at run time, which particle system code to execute in each frame. Thirdly, it describes a software architecture called the Dynamic Particle System Framework (DPSF). Simulation results show that DPSF possesses all 18 desirable features.

The purpose of this study was to describe a simplified arytenoid rotation technique and to test its applicability in excised human larynges. A non-absorbable monofilament thread is slung around the muscular process of the arytenoid cartilage through an external approach. During visual control through flexible endoscopy, two needles and a wire loop needle threader are the only instruments needed. Thread tensioning and fixation results in a stabilized arytenoid adduction. This technique avoids cricothyroid joint disarticulation and leaves the thyroid cartilage intact. The practicability of the technique was proven in five excised larynx experiments. In two clinical cases, the muscular process was slung and pulled with a monofilament thread. Tension in the vector direction parallel to the LCA muscle showed an effective and stable arytenoid rotation with complete closure of the posterior glottis. The rotational effect following sling arytenoid adduction (SAA) is similar to conventional arytenoid adduction surgery outcome. However, SAA is performed from an external approach and avoids dissection of cartilage. Challenging dissections to reach the muscular process are avoided. In some cases of unilateral vocal fold immobility, arytenoid rotation may be performed by using the SAA technique, which allows for an external and extralaryngeal approach. Further studies should assess the clinical value of this technique. In principal, the wire loop needle threader can also be employed for external vocal fold lateralization procedures.

Clinical Infectious Diseases 2010; 50(12):1635 2010 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2010/5012-0013$15.00 DOI: 10.1086/652858 In September 2008, a 48-year-old Portuguese man presented to our institution with a 6-week history of dysphonia and a 10-day history of progressive dysphagia and dyspnea. This human immunodeficiency virus (HIV)–infected patient, who was receiving antiretroviral therapy, had an undetectable plasma HIV load and had had a CD4 cell count 1350 cells/mm for the previous 2 years (nadir CD4 cell count, 201 cells/mm). In 2004, the patient had been treated for 2 mucosal carcinomas—a floor of the mouth (pT1 cN0 M0) carcinoma and an oropharyngeal (cT3 cN1 M0) carcinoma—with surgery and radiochemotherapy, and he experienced a subsequent postradiation esophageal stenosis. At physical examination, the patient presented with a good general status, absence of fever, no lymphadenopathy, and no splenomegaly. The results of a full blood count and the patient’s C-reactive protein level were within the normal range. A laryngoscopic examination showed an irregular burgeoning lesion (Figure 1A) spreading from above the posterior laryngeal commissure to the left posterior false vocal cord and left vocal cord palsy. Biopsies of the lesion were performed, and biopsy specimens were examined after May-Grünwald Giemsa staining (Figure 1B). What is your diagnosis?

The purpose of the study was to examine the morphology and biomechanical characteristics of in vivo cultured tissue-engineered human septal cartilage as a prospective autogenous transplant material for subcutaneous implantation in reconstructive procedures. Chondrocytes were enzymatically isolated from human septal cartilage biopsies. The cell number was expanded in monolayer culture. Chondrocytes were then fixed on a non-woven poly-lactide-poly-glycolide (PGLA) polymer scaffold by means of fibrin glue. The PGLA-polymer construct was implanted subcutaneously on the back of athymic mice and allowed to mature for 6 or 12 weeks. After killing the mice, the formed cartilage was tested on a material testing machine with a highly standardized reproducible setting. Biomechanical testing consisted of an indentation test, which revealed the failure load and compressive modulus of the neocartilage. The failure load shows the upper limit of supported stress. The compressive modulus is a measure of the templates' stiffness. After testing, the templates were histologically stained. Native human septal cartilage served as a control group. Histological and macroscopic examination showed cartilage formation of a hyaline-like morphology. Histological staining revealed the synthesis of abundant mucopolysaccharid matrix. The biomechanical characteristics of neocartilage proved to be of no statistical difference compared to native human septal cartilage. The failure load and compressive modulus were initially somewhat lower and reached the control group's results after 12 weeks in-vivo. Summarizing, tissue engineered nasal cartilage matches typical mechanical characteristics of native hyaline cartilage. Its elasticity and failure load are of sufficient quality to meet the clinical requirements for reconstructive surgery.

We present a preliminary free-flying occulter design using existing technology to move in formation with NGST, the Umbral Mission Blocking Radiating Astronomical Sources (UMBRAS). The purpose of the occulter is to reduce and redistribute light entering NGST. UMBRAS enhances the contrast between faint objects and bright sources allowing planet searches by imaging within a few tenths of an arcsecond of nearby stars. The occulting spacecraft would range from thousands to tens of thousands of kilometers from NGST using solar electric propulsion. Operational constraints for UMBRAS are compatible with NGST. Observing rates between a few dozen and a hundred targets per year with mission lifetimes of 2-6 years are achievable.

Traumatic events are a primary cause for local lesions of articular cartilage. If treated early, restoration of the initial joint geometry and integrity may be achieved. In large defects, sufficient material is not available to bridge the affected area. Heterologeous transplantation is not well accepted due to the risk of infection and immune response. Alternatives are cartilage-like structures, which may be cultured in vitro and transplanted into the defect site. Critical to the success of these new tissues are their mechanical properties. Goals of this study were to generate a hyaline-like cartilage structure, to evaluate its performance in vivo and to verify that its cellular and material properties meet those of native cartilage. Hyaline-like cartilage specimens were generated in vitro and implanted in the backs of nude mice. Specimens were explanted after 6 and 12 weeks, mechanically tested using an indentation test and histologically examined. In mechanical testing, stiffness and failure load significantly increased between weeks 6 and 12. At 12 weeks, mechanical properties of the hyaline-like cartilage were comparable to those of native nasal septal cartilage. Compared to native articular cartilage, the engineered tissue achieved up to 30-50% in strength and mechanical stiffness. In histological examination, specimens showed neocartilage formation. The mechanical testing procedure proved to be sufficiently sensitive to identify differences in properties between cartilage specimens of different origin and at different stages of healing. As an adjunct to histological analysis, mechanical testing may be a valuable tool for judging the utility of engineered cartilage prior to a broad clinical usage.

The isotope shift in 31 spectral lines in the nickel arc spectrum has been determined by the use of a Fabry-Perot interferometer. The normal mass shifts were calculated (\ensuremath{\approx}+0.025 ${\mathrm{cm}}^{\ensuremath{-}1}$ between ${\mathrm{Ni}}^{58}$ and ${\mathrm{Ni}}^{64}$) and subtracted from the observed isotope shifts. The differences were attributed to the specific mass and field effects. The relative shifts of levels of four configurations were deduced from the observed line shifts, these being the "complex" configurations $3{d}^{8}4{s}^{2}$ and $3{d}^{8}4s4p$ and the two-electron configurations $3{d}^{9}4s$ and $3{d}^{9}4p$. It was shown that the shifts due to the specific mass effect are a significant part of the observed shifts. Perturbations due to interconfiguration interactions were postulated to explain some of the observed shifts. The isotope shift to be expected between ${\mathrm{Ni}}^{58}$ and ${\mathrm{Ni}}^{64}$ on the basis of field effect calculations is about -0.02 ${\mathrm{cm}}^{\ensuremath{-}1}$ for a single $4s$ electron, while the shifts observed are as large as +0.190 ${\mathrm{cm}}^{\ensuremath{-}1}$. A large fraction of this shift must therefore be attributed to the specific mass effect. By noting the deviations of the relative shifts between adjacent pairs of even isotopes from those predicted by mass effect theory, it was possible to deduce the relative field effect. The relative level shift resulting from the field effect is nearly the same for the adjacent isotope pairs 60-62 and 62-64 while the relative level shift for the isotope pair 58-60 is approximately 0.004 ${\mathrm{cm}}^{\ensuremath{-}1}$ larger than that for the other adjacent isotope pairs. The arrangement of neutrons in the outermost nuclear shells is believed to account for this difference. Within the experimental error the level shift of the ${\mathrm{Ni}}^{61}$ relative to the neighboring even isotopes is such that there is no odd-even staggering of the levels.