Mechanism of the fatigue life increment due to dynamic strain ageing during hold time

The effect of hold time on the low-cycle fatigue behaviour of AlSl 4140 steel at 303 to 473 K was investigated in air and argon gas. All tests were conducted under a constant total strain amplitude of 0.5, 0.65, 1.0, 1.3 and 1.6×10^–2 with zero mean level. Experimental results show that dynamic strain ageing is occurring during the hold time period and that piled-up dislocations near the carbides are locked by the Cottrell atmosphere. Formation of the Cottrell atmosphere around dislocations near the carbides induces the redistribution of carbon or carbides in the matrix. These randomly dispersed grown up carbides behave like the increased number of dislocation pile-up sites from which fatigue cracks may initiate. Therefore, as the hold time is applied in fatigue cycles under constant strain amplitude the dislocation density at each site will be lowered to retard the fatigue damage or improve the fatigue life.     

The optical recording and thermal analysis of compact disc-recordable

Recently various types of optical discs have been developed and used. Compact Disc Recordable (CD-R) is a disc where enormous amounts of digital data can be recorded and played in currently used CD player or CD-ROM drive. The reflection and absorption rate of the laser beam in the layers of CD-R were numerically calculated. The laser beam energy absorbed in the recording layer is converted to heat, and this is transferred to the neighboring layers. The transient temperature distributions in the layers on recording were obtained numerically using ANSYS software. The written spot in the recording layer was heated far above its decomposition temperature and part of the polycarbonate substrate was heated above its glass transition temperature. After optical recording, the image of the recorded area was obtained by using an atomic forces microscope (AFM). The recording mechanism of CD-R was discussed with these numerical calculations and experimental observations.     

Synthesis, DNA binding, cytotoxicity and sequence specificity of a series of imidazole-containing analogs of the benzoic acid mustard distamycin derivative tallimustine containing an alkylating group at the C-terminus

In an attempt to produce additional alkylation and crosslinking in the minor groove of DNA, imidazole-containing analogs of distamycin were synthesized with benzoic acid mustard (BAM) and methoxyaziridinyl moieties present at the N- and C-termini, respectively. Analogs 1a-c differed in the number of methylene units (2-4 respectively) between the C-terminal carbonyl group and the methoxyaziridinyl moiety. DNA binding affinity to several polynucleotides decreased with increasing linker length, whereas DNA interstrand crosslinking ability, as measured by a plasmid gel based assay, increased. The in vitro cytotoxicity in human chronic myeloid leukemia K562 cells and the panel of human tumor cell lines at the National Cancer Institute decreased with increasing number of methylene units, and no increase in cytotoxicity was observed over compound AR-1-122 which did not contain the methoxyaziridinyl moiety. 1a-c had the same sequence selectivity of alkylation as AR-1-122, showing alkylation only at 5'-TTTTGPu sequences. The relative binding to these sequences decreased with increasing number of methylene units. The addition of a methoxyaziridinyl moiety in this group of imidazole and BAM-containing compounds can, therefore, increase crosslinking ability to naked DNA but this does not result in an increase in cytotoxicity. In contrast the cytotoxicity was related to their ability to produce sequence specific alkylation at 5'-TTTTGPu sequences.     

History of healing; bath treatment as psychiatric therapy (1900-1950)

During the first decade of the twentieth century the prolonged bath treatment was introduced as a therapy for restless patients in Dutch psychiatric institutions. They were kept for hours or days at a stretch in lukewarm water, in order to calm them down. It became a common treatment, which nevertheless was gradually replaced by occupational therapy. The rise of psychopharmacology during the fifties of this century marked the end of the prolonged bath treatment.     

Least squares subspace projection approach to mixed pixelclassification for hyperspectral images

An orthogonal subspace projection (OSP) method using linear mixture modeling was recently explored in hyperspectral image classification and has shown promise in signature detection, discrimination, and classification. In this paper, the OSP is revisited and extended by three unconstrained least squares subspace projection approaches, called signature space OSP, target signature space OSP, and oblique subspace projection, where the abundances of spectral signatures are not known a priori but need to be estimated, a situation to which the OSP cannot be directly applied. The proposed three subspace projection methods can be used not only to estimate signature abundance, but also to classify a target signature at subpixel scale so as to achieve subpixel detection. As a result, they can be viewed as a posteriori OSP as opposed to OSP, which can be thought of as a priori OSP. In order to evaluate these three approaches, their associated least squares estimation errors are cast as a signal detection problem ill the framework of the Neyman-Pearson detection theory so that the effectiveness of their generated classifiers can be measured by receiver operating characteristics (ROC) analysis. All results are demonstrated by computer simulations and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data     

Transient post-renal obstruction may protect the kidney against nephrotoxic damage--a case report

In critically ill patients, acute renal failure is mostly multifactorial in origin. In general, the simultaneous presence of several deleterious factors tends to aggravate the renal damage. The present case report describes a patient with multifactorial acute renal failure, in whom one of the factors contributing to the renal failure, i.e. transient unilateral post-renal obstruction, apparently protected the obstructed kidney against damage from other causes.     

Inhibitory action of YJA20379, a new proton pump inhibitor on Helicobacter pylori growth and urease

The use of an episiotomy for vaginal delivery is a controversial topic in modern obstetrics. If one is done, however, correct technique of perineal trauma repair is important. The usual episiotomy has traditionally been closed with interrupted suture. The use of a less reactive material, e.g. polyglycolic acid (Dexon), seem to be suitable for subcutaneous skin closure and beneficial in terms of acute postpartum discomfort and healing. The comparison of healing and patient comfort parameters between interrupted and subcutis polyglycolic acid suture used for episiotomy repair after delivery was done. Patients had follow-up during hospital stay, and two months after delivery a self administered questionnaire was sent to all women who participated, enquiring about perineal pain, resumption of sexual intercourse and cosmetics of suture line. Of 52 patients who had repair with interrupted suture, 21 were lost to follow-up. Of 65 gravidas who had repair with subcutis suture, 23 were lost to follow-up. At the 3rd day postpartum examination, patients with subcutis sutures had significantly better healing. An inflammatory process was present in 2 of 52 patients with interrupted sutures comparable with 1 of 65 in the subcutis group, and a gaping wound in 0 of 52 and 1 of 65, respectively. Recovery of function, measured by resumption of sexual activity by 8 weeks, was demonstrated in 5 of 31 patients with interrupted sutures versus 24 of 42 patients who had subcutis sutures. Episiotomy repair with subcutis polyglycolic acid (Dexon) offers significant advantages over traditional interrupted suture, both in terms of wound healing and resumption of sexual activity.     

Downregulation of BDNF mRNA and protein in the rat hippocampus by corticosterone

Previously, we showed that corticosterone regulates BDNF mRNA levels in the hippocampus. In the present study, we have investigated the time course and dose-dependency of this effect at both the mRNA and the protein level. Corticosterone was administered in doses of 30 and 1000 microgram/kg b.w. subcutaneously to adrenalectomized animals. At 3, 6, 12 and 24 h after administration BDNF and trkB mRNA levels in hippocampal subfields were measured by in situ hybridization. Our results show a dose-dependent decrease in BDNF mRNA in dentate gyrus and CA1 at 3 h. After the high dose, this decrease was 70% and 40% respectively. In addition, ELISA was performed to study if this downregulation is also detectable at the protein level. Hippocampal tissue was used from adrenalectomized animals which had received 1000 microgram/kg b.w. corticosterone 4 and 6 h before decapitation. At both time points, a decrease in BDNF protein was observed; 17% at 4 h and 14% at 6 h after corticosterone, as compared to the vehicle injected controls. TrkB mRNA levels were not affected by corticosterone. However, between 6 and 24 h after treatment, increases in trkB mRNA were observed. In conclusion, we have found a transient, dose-dependent decrease in BDNF mRNA and protein in the hippocampus, which may underly changes in neuronal plasticity in the hippocampus after short-term changes in corticosterone concentrations.     

Filter‐Free Wavelength Conversion Using Mach‐Zehnder Interferometer with Integrated Multimode Interference Semiconductor Optical Amplifiers

We propose a filter‐free wavelength conversion using a Mach‐Zehnder interferometer with monolithically integrated 2×2 multimode interference semiconductor optical amplifiers (MMI‐SOAs). The device has been optimized by considering a non‐homogeneous carrier distribution due to the self‐imaging properties of the MMI‐SOA. Static measurements show an extinction ratio of up to 18 dB and an input signal rejection ratio of up to 20 dB.