High precision quantitative angiography

Statistical considerations on the precision in the determination of blood vessel dimensions from digitized cine angiographic images are described. The resolution requirements related to "point measurements" and segmental diameter curve evaluations are discussed. The error associated with inaccurate determination of the vessel's centerline is analyzed. The concepts have been implemented on a high-speed image analyzing system, which measures blood vessel diameters with advanced automation. The performance of the system was evaluated with blood vessel phantoms, ranging in diameter from 0.88 to 6.26 mm. For these phantoms the minimum measurable change in vessel dimension over 20-pixel (-1.1 mm) long segments ranged from 3.4 to 0.2 percent, respectively.     

Versatile Macroscale Concentration Gradients of Nanoparticles in Soft Nanocomposites

Nanocomposite materials benefit from the diverse physicochemical properties featured by nanoparticles, and the presence of nanoparticle concentration gradients can lend functions to macroscopic materials beyond the realm of classical nanocomposites. It is shown here that linearity and time‐shift invariance obtained via the synergism of two independent physical phenomena—translational self‐diffusion and shear‐driven dispersion—may give access to an exceptionally high degree of flexibility in the design of scalable and programmable long‐range concentration gradients of nanoparticles in solidifiable liquid matrices.     

NONLINEAR RESPONSE OF FLAT AND CURVED PANELS SUBJECTED TO THERMOMECHANICAL LOADS

The results of an analytical study of the nonlinear response of flat and curved panels subjected to pre-existing, nondestabilizing lateral pressure and thermal loads and to mechanical edge loads are presented. The mechanical loads include uniaxial compression loads and combinations of uniaxial compression and transverse tension or compression loads that are increased monotonically into the postbuckling response range of the panels. The structural model used to analyze the panels is based on a higher order shell theory that includes transverse-shear flexibility, initial geometric imperfections, and von Karman_type geometric nonlinearities. The edges of a panel are modeled as simply supported edges with the displacement normal to the edge face either unrestrained or fully restrained. Results are presented for transversely isotropic single-layer panels and three-layer sandwich panels that illustrate how the temperature field, initial imperfections, lateral pressure loads, and mechanical edge loads interact to change the character of the nonlinear panel response. Some response curves are presented that have classic unstable, asymmetric bifurcation behavior and intense snap-through instabilities. Other results show that, for some cases, these interactions can reduce the intensity of snap-through instabilities and even eliminate this form of instability altogether for certain ranges of loading and structural parameters. In addition, results are presented that show how transverse-shear flexibility affects the interactions of the temperature field, the initial imperfections, the lateral pressure loads, and, thus, the character of the nonlinear panel response. One important finding of the present study is that linear bifurcation buckling analyses may not indicate adequately the onset of significant nonlinear deformations of a geometrically perfect, shallow curved panel for certain combined mechanical loading conditions. This finding may affect current preliminary design practice.     

Mapping the future of supply chain management: a Delphi study

Supply chain management, a field that developed from business practice and research, is undergoing a major transformation. It is changing from tactical in nature (where the major focus is on cost and delivery) to a field that is strategic in nature. However, the future issues and challenges facing managers and executives are just now becoming understood. This paper reports these issues by drawing on the findings generated by a three-phase study consisting of a literature review, a two-round Delphi study, and a workshop. Unique in this Delphi study is that it brings together leading practitioners in supply chain management with leading supply chain management researchers. The findings show that while the focus of the current tactical supply chain view is relatively limited to issues of delivery, risk, and leadership, the supply chain view of the future (i.e., five years from now) is more complex and demanding. The findings also show that there is generally no difference between researchers and practitioners in terms of how they view the issues. Finally, the study uncovers major obstacles that must be resolved before the strategic potential of future-state supply chains can be realised.     

Quasi-superactivation of classical capacity of zero-capacity quantum channels

One of the most surprising recent results in quantum Shannon theory is the superactivation of the quantum capacity of a quantum channel. This phenomenon has its roots in the extreme violation of additivity of the channel capacity and enables reliable transmission of quantum information over zero-capacity quantum channels. In this work we demonstrate a similar effect for the classical capacity of a quantum channel which previously was thought to be impossible. We show that a nonzero classical capacity can be achieved for all zero-capacity quantum channels and it only requires the assistance of an elementary photon–atom interaction process – stimulated emission.     

Lifting the curtain on the Wizard of Oz: Biased voice-based impressions of speaker size.

The consistent, but often wrong, impressions people form of the size of unseen speakers are not random but rather point to a consistent misattribution bias, one that the advertising, broadcasting, and entertainment industries also routinely exploit. The authors report 3 experiments examining the perceptual basis of this bias. The results indicate that, under controlled experimental conditions, listeners can make relative size distinctions between male speakers using reliable cues carried in voice formant frequencies (resonant frequencies, or timbre) but that this ability can be perturbed by discordant voice fundamental frequency (F?, or pitch) differences between speakers. The authors introduce 3 accounts for the perceptual pull that voice F? can exert on our routine (mis)attributions of speaker size and consider the role that voice F? plays in additional voice-based attributions that may or may not be reliable but that have clear size connotations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Double immunochemical screening test (hemoglobin and albumin) for the detection of occult intestinal bleeding

BACKGROUND AND OBJECTIVES: Chlamydia trachomatis antigen testing of clinical specimens is replacing culture as the test of choice. Because of a potential for false positive results in low prevalence populations, there is an apparent need for confirming specimens positive by enzyme immunoassay (EIA). GOAL OF THIS STUDY: To examine specimens falsely positive in the Chlamydiazyme EIA assay according to gender and specimen type. STUDY DESIGN: Testing of genitourinary specimens from men and women consecutively enrolled from five health care delivery sources in an urban Canadian population. All specimens were initially tested in the Chlamydiazyme test and all positives repeated in a confirmatory blocking assay provided by the manufacturer. Additional confirmatory testing was performed using immunofluorescence (IF) staining for C. trachomatis elementary bodies (EB's) and polymerase chain reaction (PCR). RESULTS: From Jan. 1, 1990 to June 1, 1991, multiple specimens from 656 men and 5,628 women of varying population prevalences were screened. EIA-positive specimens from women had a repeat negative rate of 22% to 27% from cervical swabs and 29% from urethral swabs. Male urethral swabs had a high repeat negative rate of 22% when EIA was the only positive test, but 2.4% when the specimen was positive by EIA and culture. EIA-positive first void urine (FVU) specimens from men had a repeat negative rate of 8.7% as opposed to 17% to 32% from women. Only 1.7% (2/115) of male FVU did not block compared to rates of 47% (22/47) to 80% (4/5) in FVU from women. Analysis of EIA optical densities (OD's) and EB counts showed an association between the absorbance range 0.1 to 1.4 OD and 0-85 EB's. The greatest number of EB's and highest OD's were seen with cervical specimens, followed by urine and urethral specimens in women infected at all three specimens. All 55 specimens that did not confirm in the blocking test had no EB's and a convenience sample of seven were negative by PCR. All of a subset of 50 blocked specimens contained EB's or were positive by PCR. CONCLUSIONS: Although a variable proportion of specimens may not repeat positive in the EIA, use of the blocking reagent to confirm the repeat positives is highly recommended and the rate of blocking may be heavily influenced by gender and specimen type.     

Antimicrobial treatment options in the management of odontogenic infections

Most acute orofacial infections are of odontogenic origin. In normal hosts, however, they usually do not occur without some type of predisposing condition. Early recognition and management of acute orofacial infections is critical, because rapid systemic involvement can occur, especially in children. Antimicrobial therapy has an essential role in the management of these infections. If it is initiated before surgery, it can shorten the period of infection and minimize associated risks. The etiology of odontogenic infections is usually attributed to the endogenous flora of the mouth, and not to the introduction of non-resident bacteria. Odontogenic infections are typically polymicrobial; however, anaerobes generally outnumber aerobes by at least four fold. The penicillins have historically been used as the first-line therapy in these cases, but increasing rates of resistance have lowered their usefulness. Bacterial resistance to this class of agents is predominately achieved through the production of beta-lactamases. Clindamycin, because of its broad spectrum of activity and resistance to beta-lactamase degradation, is an attractive first-line therapy in the treatment of odontogenic infections.