An unusual embolization of a projectile in the superficial femoral artery

The authors present an account on a gunshot wound which penetrated into the lateral side of the distal chest on the right. They describe acute treatment of severe haemorrhagic shock by suture of a lacerated with liver segment and resection of the upper pole of the right kidney. The projectile was not searched for because of the patients general serious condition. After 30 days the patient was discharged in a good condition. Shortly after discharge, i.e. cca one month after the injury, the patient developed signs of chronic ischaemia of the left lower extremity-finally claudications after 150 meters. Based on peripheral arteriography, which revealed the projectile in the area of the beginning of the superficial femoral artery and an ample collateral circulation, surgery was initiated. The bullet was extracted from the lumen of the superficial femoral artery from longitudinal arteriotomy. The artery was then treated by thrombectomy and a venous patch. Peroperative arteriography indicates satisfactory passage into the periphery. The authors try to reconstruct the pathway of the shot and in particular how the projectile penetrated into the artery. They emphasize the necessity to look for the projectice at the site of the shot wound. The objective of the paper is to make readers familiar with a case of uncommon embolization of a projectile into the superficial femoral artery and mistakes which may occur during treatment of a gunshot wound. The result is that the patient is quite free from complaints, as was confirmed by repeated out-patient check-ups.     

Frictional Response of PTFE Sliding Bearings at High Frequencies

Dynamic tests were done on polytetrafluoroethylene (PTFE) sliding bridge bearings to evaluate their frictional characteristics at frequencies above 1 Hz. High frequency seismic responses of PTFE bearings are expected to occur in bridge structures in eastern North America, where the estimated ground motion is well above 1 Hz. Three different PTFE-steel interfaces were tested at frequencies ranging from 0.02 Hz to 5 Hz, with displacement amplitudes of up to ±70 mm and under confining pressures ranging from 5 MPa to 45 MPa. The experimental results showed a significant initial transient frictional response at frequencies above 1 Hz before the dynamic, steady-state, frictional behavior was achieved. This transient response is characterized by an initial high static coefficient of friction that slowly decreases to a dynamic steady-state coefficient of friction after several response cycles. Modifications to an existing mathematical friction model are proposed to take into account this initial transient frictional response.     

Influence of ZnCl2 on the structure and mechanical properties of polyacrylonitrile fibers

The structure and mechanical properties of polyacrylonitrile fibers containing small amounts of Zn²⁺ were investigated. It is possible to interpret the influence of ZnCl₂ on the fibers by diffusion. Fibers spun from spinning dope containing ZnCl₂ may have a denser and finer structure because ZnCl₂ in the spinning dope retards the coagulation rate. The tensile strength and modulus of the fibers are much improved because of the retardation of coagulation. It is probable that the complexation between Zn²⁺ and CN groups does not contribute to the improvement of the mechanical properties because the amount of ZnCl₂ added in a spinning dope is extremely small.     

Robust Approximation of Offsets,Bisectors, and Medial Axes of Plane Curves

Most methods for computing offsets, bisectors, and medial axes of parametric curves in the plane are based on a local formulation of the distance to a curve. As a consequence, the computed objects may contain spurious parts and components, and have to be trimmed. We approach these problems as global optimization problems, and solve them using interval arithmetic, thus generating robust approximations that need not be trimmed.     

BIACORE analysis of histidine-tagged proteins using a chelating NTA sensor chip

While BIACORE instruments are routinely used for kinetic measurements and for the determination of binding constants, the immobilization of a ligand onto the sensor chip surface has to be individually optimized for every system. We show here that the histidine (His) tag, routinely used in protein purification and in detection is an ideal tag for immobilization, despite the intrinsically low affinity between an immobilized metal ion and the His tag. This is due to strong rebinding effects caused by the high surface density of immobilized Ni2+-nitrilotriacetic acid (NTA) on the chips used here. The immobilization of the ligand can be adjusted to a low level using the same chip, such that mass transport limitation and rebinding of the analyte to the immobilized ligand is minimal. Nine different proteins with different numbers of His tags were tested for stable binding to the Ni2+-NTA surface. Most proteins with one His tag dissociate very rapidly from the Ni2+-NTA surface, and the KD for the interaction between His tag and Ni2+-NTA was estimated to about 10(-6) m at neutral pH. In contrast, two His tags are usually found to be sufficient for stable binding. The kinetics of the chaperonin system of Escherichia coli GroEL and GroES were analyzed as a model using this system and found to be very similar to those obtained with covalently immobilized ligands. The sensor chip can be reused many times, because of the powerful regeneration methods. The ligand can be freshly immobilized after each cycle, thus eliminating potential denaturation upon regeneration as a source of error.     

View specificity, array specificity, and egocentrism in young children's drawings.

Examined the concept of egocentrism in an experiment in which 80 children (aged 6 yrs 1 mo to 7 yrs 2 mo) were asked to draw 2 pictures of an array of 2 objects, one characterizing their own view and the other characterizing the view of another child seated in a different position. Ss were able to represent their partner's view when the latter presented few problems in graphic complexity or mental rotation. Ss who were asked to draw their own view after drawing their partner's produced more view specific drawings than Ss asked to draw their own view first. It is concluded that the production of array-specific representations of spatial relations in young children's drawings should not be seen as a manifestation of egocentrism. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biased Language Use in Stereotype Maintenance: The Role of Encoding and Goals.

In 4 studies, the authors investigated the relative impact of biased encoding of information and communication goals on biased language use. A category label (linguistic expectancy bias, Study 1) or a group label (linguistic intergroup bias, Study 2) was presented either before or after a story that participants were asked to communicate. Biased language use only emerged when participants learned about the group membership of the actor or the category label before hearing the story. However, communication goals had an effect on language use at the retrieval stage, independent of encoding (Studies 3 and 4). Although communication goal effects seemed to overwhelm encoding effects, encoding still influenced language use under externally imposed time pressure (Study 3) and self-imposed time constraints (Study 4). This research reaffirms the importance of both cognitive and communicative processes in stereotype maintenance and highlights the conditions under which they each operate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)