The influence of structural properties on the dye diffusion and dyeabilty of PA 6 fibres

The relationships were investigated between the structural and dyeing properties of different structurally modified PA 6 fibers. PA 6 monofilament yarn samples were applied having different crystalline degrees and different content of alpha, respectively gamma crystalline modification. The diffusion coefficients of two different acid dyes were determined together with the content of dyestuff absorbed (under specific conditions) by fiber samples. In order to estimate colorimetry method from the viewpoint of polymer structural change detection, the colors of the dyed PA 6 samples were determined (L*, a*, b*, C*, h coordinates) and the color differences (L*, a*, b*, C*, H*, E*) were calculated between untreated standard and structurally modified samples. The dyeability of PA 6 fibers depended mainly on the way in which crystallinity had been achieved, i.e. on the material's history. Different crystalline modifications caused different sorption properties and fiber dyeability. Smaller increases (app 20%) of crystallinity degree caused a decrease in diffusion coefficients. Contrary to expectations, the significant increase of crystallinity degree (app 50%) had an influence on the increase of dyeability, presumably owing to the formation of larger empty spaces in the structure. The results achieved by colorimetry were in good correlation with dye absorption measurements. The colorimetry of dyed fiber samples was sensitive enough to detect even small differences in the quantities of absorbed dyestuff.     

Costlets: A Generalized Approach to Cost Functions for Automated Optimization of IMRT Treatment Plans

We present the creation and use of a generalized cost function methodology based on costlets for automated optimization for conformal and intensity modulated radiotherapy treatment plans. In our approach, cost functions are created by combining clinically relevant “costlets”. Each costlet is created by the user, using an “evaluator” of the plan or dose distribution which is incorporated into a function or “modifier” to create an individual costlet. Dose statistics, dose-volume points, biological model results, non-dosimetric parameters, and any other information can be converted into a costlet. A wide variety of different types of costlets can be used concurrently. Individual costlet changes affect not only the results for that structure, but also all the other structures in the plan (e.g., a change in a normal tissue costlet can have large effects on target volume results as well as the normal tissue). Effective cost functions can be created from combinations of dose-based costlets, dose-volume costlets, biological model costlets, and other parameters. Generalized cost functions based on costlets have been demonstrated, and show potential for allowing input of numerous clinical issues into the optimization process, thereby helping to achieve clinically useful optimized plans. In this paper, we describe and illustrate the use of the costlets in an automated planning system developed and used clinically at the University of Michigan Medical Center. We place particular emphasis on the flexibility of the system, and its ability to discover a variety of plans making various trade-offs between clinical goals of the treatment that may be difficult to meet simultaneously.     

Assignment of swimmers to dual meet events

Every fall, thousands of high school swimming coaches across the country begin the arduous process of preparing their athletes for competition. With a grueling practice schedule and a dedicated group of athletes, a coach can hone the squad into a cohesive unit, poised for any competition. However, oftentimes all preparation is in vain, as coaches assign swimmers to events with a lineup that is far from optimal. This paper provides a model that may help a high school (or other level) swim team coach make these assignments. Following state and national guidelines for swim meets, we describe a binary integer model that determines an overall assignment that maximizes the total number of points scored by the squad based on the times for swimmers on the squad and for the expected opponent.     

When redundant on-screen text in multimedia technical instruction can interfere with learning

It is frequently assumed that presenting the same material in written and spoken form benefits learning and understanding. The present work provides a theoretical justification based on cognitive load theory, and empirical evidence based on controlled experiments, that this assumption can be incorrect. From a theoretical perspective, it is suggested that if learners are required to coordinate and simultaneously process redundant material such as written and spoken text, an excessive working memory load is generated. Three experiments involving a group of 25 technical apprentices compared the effects of simultaneously presenting the same written and auditory textual information as opposed to either temporally separating the two modes or eliminating one of the modes. The first two experiments demonstrated that nonconcurrent presentation of auditory and visual explanations of a diagram proved superior, in terms of ratings of mental load and test scores, to a concurrent presentation of the same explanations when instruction time was constrained. The 3rd experiment demonstrated that a concurrent presentation of identical auditory and visual technical text (without the presence of diagrams) was significantly less efficient in comparison with an auditory-only text. Actual or potential applications of this research include the design and evaluation of multimedia instructional systems and audiovisual displays.     

SIOP Working Committee on psychosocial issues in pediatric oncology: guidelines for communication of the diagnosis

A 44-year-old man with a St. Jude mitral valve was admitted because of progressive pulmonary edema. He was diagnosed with prosthetic heart valve thrombosis (PHVT) based on the findings of "muffled" prosthetic valve clicks. Doppler echocardiographic evidence of severe mitral stenosis and transesophageal echocardiographic evidence of limited mitral valve motility. Because the patient hesitated to undergo our recommended surgical treatment, he was immediately treated with intravenous recombinant tissue plasminogen activator (100 mg over 3 h) followed by heparinization. Two hours after the thrombolytic therapy, the prosthetic valve clicks became clearly audible and his congestive symptoms were dramatically improved. Follow-up echocardiography no longer-showed significant mitral valve obstruction. A transient cerebral ischemic attack occurred at the end of thrombolytic therapy but there were no neurologic sequalae. The patient, on warfarin therapy, was well at follow-up 8 months after discharge. Surgical intervention has long been the standard therapy for patients with PHVT. Our case experience suggests that thrombolytic therapy may be considered as an effective alternative to surgical intervention for selected patients with PHVT. In this report, we also review the current literature regarding the indications, effectiveness and safety of thrombolytic therapy in PHVT.     

Multiple aspect-ratio structural integration in single crystal silicon (MASIS) for fabrication of transmissive MOEMS modulators

A novel fabrication process, named MASIS (multiple aspect ratio structural integration in single-crystal-silicon), is introduced for the implementation of single-crystal-silicon microstructures characterized by distinct aspect ratios to be fabricated in the same device layer. The MASIS process was especially designed for fabrication of transmissive MOEMS (Micro-Opto-Electro-Mechanical-Systems) modulators incorporating large field areas, and driven by long-stroke comb-drive actuators combined with folded suspensions. The comb-drive actuators were designed to achieve large amplitude of vibration and high natural frequencies, which allow large aperture areas at high operational frequency. The MASIS process consists of selective thinning of the device thickness in the shutter area, reducing payload mass, while preserving higher thickness of the suspension springs and comb-drive transducer fingers, thereby increasing the natural frequency of the device and reducing actuation voltages. A modulator was successfully fabricated, demonstrating maximum displacement of 50 μm at 1 kHz in resonance using an actuation voltage of 15 Vpp in air. The MOEMS modulator was adapted as integral part of a solid-state photodetection system to overcome the low-frequency noise.     

Positional Scanning Synthesis of a Peptoid Library Yields New Inducers of Apoptosis that Target Karyopherins and Tubulin

We describe the synthesis of a library of 11 638 N‐alkylglycine peptoid trimers in a positional scanning format with adjustment of reaction conditions to account for different reactivities of the monomer building blocks. Evaluation of the library by high‐content phenotypic screening for modulators of the cytoskeleton and mitosis resulted in the identification of two apoptosis‐inducing peptoids, which, despite their structural similarity, target different proteins and cellular mechanisms. Whereas one peptoid binds to karyopherins, which mediate nuclear transport, the other N‐alkylglycine trimer binds tubulin at the vinca alkaloid binding site.     

Influence of bifunctionality of reactive dyes on the bending rigidity of viscose printed with polysaccharide thickeners

The bending rigidity and colour depth of viscose printed with a number of reactive dyes in the presence of alginate and guar gum thickeners has been investigated. Interactions between the fabric, the dyes and the thickener were evaluated to determine the bending rigidity of the printed substrate. The results show that mono- or bi-functional reactive dyes cause undesired stiff fabric handle depending on the structure (the type of the reactive system and the reactive group), the reactivity and the concentration of the reactive dye used. These interactions differ to a greater degree when guar gum thickeners are used.     

Theoretical and experimental studies of Schottky diodes that use aligned arrays of single-walled carbon nanotubes

We present theoretical and experimental studies of Schottky diodes that use aligned arrays of single-walled carbon nanotubes. A simple physical model, taking into account the basic physics of current rectification, can adequately describe the single-tube and array devices. We show that for as-grown array diodes, the rectification ratio, defined by the maximum-to-minimum-current-ratio, is low due to the presence of metallic-single-walled nanotube (SWNT) shunts. These tubes can be eliminated in a single voltage sweep resulting in a high rectification array device. Further analysis also shows that the channel resistance, and not the intrinsic nanotube diode properties, limits the rectification in devices with channel length up to 10 μm.