Inkjet Printing of Polymers: State of the Art and Future Developments

Inkjet printing is considered to be a key technology in the field of defined polymer deposition. This article provides an introduction to inkjet printing technology and a short overview of the available instrumentation. Examples of polymer inkjet printing are given, including the manufacturing of multicolor polymer light‐emitting diode displays, polymer electronics, three‐dimensional printing, and oral dosage forms for controlled drug release. Special emphasis is placed upon the utilized polymers and conditions, such as polymer structure, molar mass, solvents, and concentration. Studies on viscoelastic fluid jets and the formation of viscoelastic droplets under gravity indicate that strain hardening is the key parameter that determines the inkjet printability of polymer solutions.     

Relative susceptibilities of XPA knockout mice and their heterozygous and wild-type littermates to UVB-induced skin cancer

Sensitometric techniques for performing processor quality control in laser imaging systems are analyzed in this study. The sensitivity of conventional x-ray films using simulated screen-light sensitometry is compared with helium-neon (HeNe) laser film exposed with a simulated red-light sensitometer, a standalone (reference) laser sensitometer, an experimental (unstable) laser sensitometer, and laser printers. Infrared (IR) laser film exposed with an IR laser diode and a simulated IR sensitometer are also evaluated. It is demonstrated that laser-generated step tablets provide an easy and reliable method of performing laser film processor quality control.     

Zerkleinerung von Abfällen mittels Rotorscheren,Rotorreißern und Schraubenreißern

Starting from the properties of the materials constituting waste, approaches suitable for size reduction of tough materials are considered. The rotary shears, rotary shredders, and screw shredders that have recently come into use for preliminary, coarse, and medium-level size reduction of bulky household waste, scrap wood, used tyres, biological waste, old documents are now widespread. The forces exerted by these machines and their design and important design parameters are examined. A necessary detailed comparison of the three basic types of machine depending upon the nature of the material handled (systematic size-reduction studies) has yet to be performed.     

Michaelis-Menten kinetics model of oxygen consumption by rat brain slices following hypoxia

In the present study, we have measured partial pressure of oxygen (pO2) profiles through rat brain slices before and after periods of hypoxia (5 and 10 min) to determine its effect on tissue oxygen demand. Tissue pO2 profiles were measured through rat cerebral cortex slices superfused with phosphate buffer using oxygen (O2)-sensitive microelectrodes at different times in controls [40% O2 balance nitrogen (N2)], and at different times before and after 5 or 10 min of hypoxia (100% N2). A one-dimensional, steady-state model of ordinary diffusion with a Michaelis-Menten model of O2 consumption where the maximal O2 consumption (Vmax) and the rate at half-maximal O2 consumption (Km) were allowed to vary was used to determine the kinetics of O2 consumption. Actual pO2 profiles through tissue were fitted to theoretical profiles by a least-squares method. Vmax varied among penetrations in a control slice and among slices. Vmax seemed to decrease after hypoxic insult, but the change was not statistically significant. The Km value measured before hypoxia was lower than the first Km value measured after the end of hypoxia, indicating that hypoxia induced a compensatory change in the metabolic state of the tissue. Km increased immediately after both 5- and 10-min hypoxic insults and returned to normal after recovery for each case. It seems that during and immediately after short periods of hypoxia, Km increases from near zero but returns to normal values within a few minutes.     

3D reconstruction by high resolution MR tomography of the inner ear

By means of modern 3D-visualization systems it is possible to render detailed reconstructions of very small morphological structures such as the inner ear. Aim of the present study was to demonstrate the imaging quality of a new 3D-segmentation program developed in the University of Hamburg. The investigation was carried out on a high-resolution MR-tomography of the author's labyrinth and facial nerve. The images were obtained with a fast-field-echo technique using a surface coil. 32 axial slices of 1.0 mm thickness were used for reconstruction. Thus it was possible to completely visualize cochlea, semicircular canals and facial nerve. Especially the filiform substructures of the inner ear could reliably be reconstructed. So the content of information of the MR-investigation could be increased by the 3D-technique applied.     

Immunochemical detection of cyclobutane thymine dimers in epidermal Langerhans cells of ultraviolet B-irradiated hairless mice

Integrity of sensory and motor function is essential in the maintenance of continence. The pudendal nerve assumes a central role being a mixed sensory and motor nerve. Neuropathic changes may therefore lead to incontinence and stretch injury to the pudendal nerve has been implicated as an aetiological factor. However pudendal neuropathy, altered anal sensation and perineal descent do not always correlate in the same patient. To investigate this further we evaluated the effect of a simulated defaecation strain on pelvic floor neurological function in a group of patients with constipation and incontinence. Pudendal nerve terminal motor latency (PNTML) and anal electrosensitivity (AS) were measured at rest and after a simulated defaecation strain of 1 minute. At rest PNTML correlated with AS (r = 0.461, P = 0.003). Twenty-five patients had perineal descent of more than 1 cm on straining, and 13 had descent below the ischial tuberosities. After 1 minute of straining AS was significantly (P < 0.001) blunted and PNTML was significantly (P < 0.001) prolonged both changes returning to normal after 3 minutes. AS was significantly (P = 0.01) more blunted in patients with perineal descent of more than 1 cm. PNTML was significantly (P = 0.01) more prolonged in patients with perineal descent of more than 2 cm. Age was significantly correlated with AS (r = 0.45, P = 0.004) and PNTML (r = 0.49, P = 0.002). Anal sensation and PNTML are acutely affected by defaecation straining, and changes may occur in patients without perineal descent. Functional changes occur equally in constipated and incontinent patients.     

Secure anastomoses of the large intestine (especially with transanal drainage

The results of colonic resections were investigated in 356 patients in a retrospective analysis. Special attention was directed to the effectiveness of a transrectal tube, leading to decompression of the anastomosis for the first five days. Under elective conditions, the overall complication-rate was 12.7%. In emergency cases, these complications were 51.5% (one third of these cases had a decompression-tube). The clinical relevant leakage-rate under elective conditions ranged to 1.7%. Postoperative mortality related to surgical complications turned out to be 1.5% under elective conditions. The emergency operations had a high mortality which ranged to approximately 15.2%. No patient with leakage of a colorectal anastomosis died when the transrectal decompression-tube was applied. Such a safety in anastomotic healing of colon and rectum anastomoses can otherwise only be achieved by using the protection of a diverting colostomy or ileostomy. The use of the transrectal decompression-tube also avoids stomal complications and the second operation. There is no indication for the decompression-tube in emergency operations with purulent or faecal peritonitis. In these cases a fundamentally different treatment is mandatory.