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Electrospun nanofibers were captured directly between two steel rods that functioned as the “grips” of the tensile testing apparatus. Tension was applied to the selected nanofiber by displacing one of the grips at controlled rates or in steps. The stress was revealed by the deflection of a nanofiber, caused by the drag force from a broad stream of air, which flowed perpendicular to the fiber at a known velocity. The deflected position and shape of the nanofiber was observed with a light arrangement optimized to produce bright glints that were photographed with a camcorder. Image analysis of the catenary shapes of the nanofibers was combined with scanning electron microscopy measurements of the diameter of the ends of the tested fibers to evaluate the mechanical properties. Measurements of properties, including tensile strength, tensile modulus and elongation-to-break, of thin electrospun fibers were obtained on six chemically different polymers: nylon 6 , poly(ethylene oxide), polyvinylpyrrolidone, poly(2-ethyl-2-oxazoline), Tecoflex ® and Tecophilic ® polyurethanes. To the best of our knowledge, this is the first report of tensile data on single polyvinylpyrrolidone and poly(2-ethyl-2-oxazoline) nanofibers. These soft nanofibers with low strain to break rarely survive the sample loading procedures where single fiber manipulation is involved. This method complements difficult mechanical measurements of polymer nanofibers and low strength microfibers made on miniature mechanical testing devices. Mechanical hysteresis curves were attained that show the recoverable and non-recoverable tensile deformation of PEO , nylon and Tecophilic ® polyurethane fibers.

Rotary letterpress and flexographic printing were investigated for their potential use in making electrically conductive structures. A variety of test patterns were designed to determine some of the printing process capabilities. Antennas for radio frequency identification tags were printed using these techniques. The ink used in this study was a dispersion of silver flakes, and organosilver compounds in an organic vehicle. A variety of printing parameters (inking time, inking speed, printing speed, and printing force) were studied. The printed test patterns and antennas were characterized by a profilometry, electron and optical microscopy, and electrical measurements.

The convergence of materials science, printing, and electronics promises to offer low cost and high volume production of devices such as transistors, RFID tags, wearable electronics and other novel applications. Although a number of “soft lithographic” techniques have been used to make these devices, they are slow and have a limited production volume [5], [14-15].Here high volume printing processes like rotary letterpress, flexography and offset lithography have been investigated for patterning conductive materials [1]. The synthesis and development of conducting inks using electrically functional polymers has been studied. The feasibility of using such inks in high volume printing processes has been studied. An attempt has been made to print conductive interdigitated electrodes using these inks to obtain uniform coating properties and appropriate electrical characteristics. Various process parameters like type of substrate, inking time and speed, printing pressure, printing force and ink formulation have been investigated.

Printing is a promising technique to fabricate commercial organic electronic devices such as OLED, TFT, solar cells and sensors. In this investigation, we report the application of high volume flexographic printing, which makes low cost and batch production possible. Commercial RFID tags have been printed using metallic inks with organic compounds in the Printing Applications Lab (PAL) at Rochester Institute of Technology (RIT). Polyaniline ink was prepared and printed by flexography in the form of test targets and Interdigitated electrodes (IDE). The conductivity can be controlled by different levels of doping. Furthermore, multiple impression printing was used to print overlapping functional layers to obtain all printed organic electronic devices like chemical vapor and humidity sensors. Optical profilometry and SEM were used to analyze the surface and interface structure. Sensitivity was measured and compared with commercial devices.

WITH two American and five foreign companies now engaged in the manufacture of therapy tubes, the selection of one which will operate most efficiently and economically under a given set of circumstances may be a confusing and difficult task. Too often the problem resolves into an argument on the relative merits of the various mechanical principles and construction details advocated by different manufacturers. Unbiased opinions of experienced men are not easy to obtain, simply because their experience is usually confined to one make. The reliability of all the present manufacturers is rather well established; it is, therefore, safe to conclude that the product of any of them, given proper care and operated under the conditions and within the capacity for which it is designed, will give satisfactory service. There are more practical considerations. Before attempting to select a tube, one should know definitely the factors of voltage and milliamperage under which it is to operate. This will be determined by ...

Spontaneous pneumothorax is not commonly seen in children. Scott (4), in a review of the literature in 1929, collected 177 cases in children of various ages. The rarity of the condition during the first year of life, however, is indicated by the fact that Rogatz and Rosenberg (1) could find only 12 recorded cases up to 1931. Since that time about ten more have been reported. The following two cases have come to our attention during the past year. Case 1. Baby N., white, male, age 4 weeks, admitted to St. Francis Hospital June 24, 1933, on the service of Dr. W. E. Johnson. Present Complaint.—Cyanosis and difficult, rapid breathing. Past History.—The infant had a normal delivery. Respiration began without difficulty and apparently was entirely normal. After the customary two weeks' period the child was removed from the hospital in excellent condition. Present Illness.—For the past four or five days the patient has had a “cold.” On the day of admittance the child suddenly became cyanotic and there was marked...

Background Screening and determining the immune status of individuals for hepatitis B is usually done by detecting hepatitis B surface antigen (HBsAg) and hepatitis B surface antigen-specific antibodies (HBsAb). In some countries with the highest viral burden, performing these assays is currently impractical. This paper explores the use of filter paper as a blood specimen transport medium. Methods Samples, chosen from routine clinical laboratory pool, were applied and dried onto filter paper. Eluates, from the paper samples, were analyzed as routine clinical specimens on ADVIA Centaur 5634® immunoassay analyzers using the standard HBsAg and HBsAb kits. Dried blood samples were subjected to a range of environmental conditions in order to assess stability. Results After drying and elution the assays showed linearity and precision comparable to clinical assays performed on fresh serum. Elutions at various times during a 149 day incubation period showed very little variability in the Index numbers. All analytes were temperature stable except for a decrease in the HBsAg signal at 42°C. Conclusions Filter paper is an acceptable storage and transport medium for serum to be used in the detection of hepatitis B markers if atmospheric variability can be controlled. HBsAg, HBsAb and HBcAb are all stable for at least five months under storage conditions below room temperature. Drying specimens, particularly serum, on filter paper at remote locations, offers a reasonable solution to the problem of hepatitis surveillance in underdeveloped regions, although some attempt at temperature control might be desirable.

The most conspicuous defect in the present accepted methods for the management of peptic ulcer is the lack of any dependable means of establishing that the lesion is healed. The interval between the onset of symptomatic relief, which is usually effected within a few days after the institution of medical treatment, and the complete healing of the ulcer undoubtedly varies greatly, and the time at which the latter takes place in individual cases cannot be established by any known procedure. Besides enabling one to answer the patient's persistent question "Is my ulcer healed," such a procedure, if it could be brought to light, would result in other advantages. By its employment in a sufficiently large number of controlled cases, information might be gathered as to the relative effectiveness of the widely varying methods of treatment now in vogue, thus ending many an argument. The patient would be benefited more directly