Evaluation of polycaprolactone − poly‐D,L‐lactide copolymer as biomaterial for breast tissue engineering

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry     

A graphics simulator for a robotic arm

A graphics robot simulator designed for an IBM PC/XT/AT or PS/2 personal computer is presented. The simulator is a terminate-and-stay resident (TSR) program that runs in the background and intercepts commands that would normally go to the robot controller through the COM1 serial communication device. With the use of the simulator, students can develop and test robot control programs offline without a physical robot present, using the language of their choice. The status of the simulated robot is available through a 3-D graphics display and a one-line text window, each of which can be activated from the keyboard or from within a user program. Data files are used to specify the robot to be simulated and the environment or workcell within which it is to operate. Currently supported robots include the Rhino XR-3 educational robot and the Adept One and Inteledex 660 industrial robots. The workcell features an overhead camera and objects that can be sensed by the camera and manipulated by the robot.<>     

Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water

We present a new hybrid numerical method for computing the transport of a passive pollutant by a flow. The flow is modeled by the Saint-Venant system of shallow water equations and the pollutant propagation is described by a transport equation. The idea behind the new finite-volume-particle (FVP) method is to use different schemes for the flow and the pollution computations: the shallow water equations are numerically integrated using a finite-volume scheme, while the transport equation is solved by a particle method. This way the specific advantages of each scheme are utilized at the right place. This results in a significantly enhanced resolution of the computed solution     

Image quality evaluation based on recognition times for fast image browsing applications

Mean squared error (MSE) and peak signal-to-noise-ratio (PSNR) are the most common methods for measuring the quality of compressed images, despite the fact that their inadequacies have long been recognized. Quality for compressed still images is sometimes evaluated using human observers who provide subjective ratings of the images. Both SNR and subjective quality judgments, however, may be inappropriate for evaluating progressive compression methods which are to be used for fast browsing applications. In this paper, we present a novel experimental and statistical framework for comparing progressive coders. The comparisons use response time studies in which human observers view a series of progressive transmissions, and respond to questions about the images as they become recognizable. We describe the framework and use it to compare several well-known algorithms (JPEG, set partitioning in hierarchical trees (SPIHT), and embedded zerotree wavelet (EZW)), and to show that a multiresolution decoding is recognized faster than a single large-scale decoding. Our experiments also show that, for the particular algorithms used, at the same PSNR, global blurriness slows down recognition more than do localized "splotch" artifacts.     

Phase function encoding of diffractive structures

We analyzed the direct sampling (DS) method for diffractive lens encoding, using exact electromagnetic diffraction theory. In addition to previously published research [Pure Appl. Opt. 7, 565 (1998)] we present what we believe to be new results for TM polarization. We found that the validity of the scalar-based DS method is even more extended for TM than for TE polarization. Additionally, we fabricated and characterized DS-encoded blazed gratings and found good agreement between the experimental and theoretical diffraction efficiencies. We analyzed quantitatively the influence of the encoding schemes DS and analytic quantization (AQ) on the quality of the focal spot. We also investigated the focal spot sizes (FWHM) and the Strehl ratios of the DS- and the AQ-encoded cylindrical lenses.     

Cardiac syncope due to transient coronary artery occlusion: the role of percutaneous angioplasty

A case of cardiac syncope is presented, associated with single vessel coronary disease. The mechanism of the syncope would appear to be a ventricular arrhythmia with transmural myocardial ischaemia due to transient occlusion of the diseased coronary artery. The symptoms and electrocardiographic abnormalities were reproduced and subsequently abolished by percutaneous coronary angioplasty.     

Helicobacter pylori infection: prevalence and clinical relevance in a large company

Although gastrointestinal (GI) illnesses account for considerable sick absenteeism, there have been few workplace studies of GI disorders. We determined the prevalence of Helicobacter pylori infection by serology and assessed its relation to upper GI tract complaints, personal ulcer history, and family history of stomach cancer in 6,143 employees (mean age, 40.4 years) at BASF's main chemical production facilities in Ludwigshafen, Germany. Employees were recruited during occupational health clinic visits (n = 4,488) and through broad communications efforts (n = 1,655). Participation among clinic attendees was 66%, and this recruitment method was particularly effective in reaching shift employees. Positive immunoglobulin G (IgG) serology (38.2%), ulcers (4.9%), nonulcer dyspepsia (20.4%), and a family history of stomach cancer (6.1%) were common occurrences in this work setting. Further diagnostic evaluation and eradication therapy was recommended for 795 employees (12.9%), based on a combination of positive serology and either upper GI tract complaints or family stomach cancer history, and has been completed for 541 employees. A weak but consistent association was seen between positive serology and cigarette smoking, and shift work was found to be associated with positive serology, but not with ulcer or nonulcer dyspepsia occurrence.     

Yersinia arthritis (author's transl)

Yersinia arthritis is an acute oligo- or, more rarely, polyarthritis. It occurs after pyrexic diarrhoea of several days, often associated with right-sided lower abdominal pain. The disease is caused by Yersinia enterocolitica and four such cases, confirmed serologically in three, are described. In one case fluid from the knee-joint was antibody-positive. It was not possible to culture the causative organism, probably because all patients had previously been treated with an antibiotic. Rheumatic fever and Reiter's disease must be considered in the differential diagnosis. Because pharyngitis, transitory ECG changes and conjunctivitis may occur in the early stages of Yersinia arthritis, the diagnosis may be missed. Prognosis of Yersinia arthritis is good, with complete cure within weeks or months. Demonstration of HLA-B 27 in all four cases points to a genetic disposition.     

Therapeutic death: A look at Oregon's law.

Oregon voters approved the first American statute authorizing physician-assisted suicide, the Oregon Death With Dignity Act, in 1994. The authors of this article identify some positive and negative psychological effects of laws such as Oregon's on patients. Generally, they conclude, on the basis of psychological theory and the available data, that laws such as Oregon's benefit patients psychologically. Undoubtedly, however, there exist important possible antitherapeutic effects on patients, and the authors hope that discussion of both therapeutic and antitherapeutic consequences will stimulate future research by social scientists in this area. (PsycINFO Database Record (c) 2010 APA, all rights reserved)