Carrier-induced ferromagnetism in n-type ZnMnAlO and ZnCoAlO thin films at room temperature

The realization of semiconductors that are ferromagnetic above room temperature will potentially lead to a new generation of spintronic devices with revolutionary electrical and optical properties. Transition temperatures in doped ZnO are high but, particularly for Mn doping, the reported moments have been small. We show that by careful control of both oxygen deficiency and aluminium doping the ferromagnetic moments measured at room temperature in n-type ZnMnO and ZnCoO are close to the ideal values of 5mB and 3mB respectively. Furthermore a clear correlation between the magnetisation per transition metal ion and the ratio of the number of carriers to the number of transition metal donors was established as is expected for carrier induced ferromagnetism for both the Mn and Co doped films. The dependence of the magnetisation on carrier density is similar to that predicted for the transition temperature for a dilute magnetic semiconductor in which the exchange between the transition metal ions is through the free carriers.Comment: 14 pages pd

Impact of melatonin supplementation in the rat spermatogenesis subjected to forced swimming exercise

Oxygen consumption increases many times during exercise, which can increase reactive oxygen species. It negatively affects fertility in male athletes. Melatonin is exerting a regulatory role at different levels of the hypothalamic-pituitary-gonadal axis. However, there is no evidence that the protective effects of melatonin persist after long duration exercise on the spermatogenesis. Therefore, this study was conducted to examine the impacts of melatonin on the testis following the administration of swimming exercise. Rats were separated into five different groups, including Control, sham M: received the solvent of melatonin, M: received melatonin, S: the exercise protocol, MS: received melatonin and the exercise protocol. After 8weeks, animals were scarified and antioxidant enzymes levels of testes, spermatogenic cells apoptosis and sperm quality were measured. Swimming decreased all parameters of spermatozoa. Nevertheless, melatonin could significantly improve the progressive motility of spermatozoa in MS rats. Swimming caused an increased apoptosis of S group and decreased all antioxidant enzymes. Melatonin could drastically reduce apoptosis and increased these enzymes. Therefore, melatonin seems to induce the production of antioxidant enzymes of testicular tissues and diminish the extent of apoptotic changes caused by forced exercise on the testis, which can, in turn, ameliorate the sperm parameters

Impact of automatic identification system (AIS) on safety of marine navigation

Automatic Identification System (AIS) was introduced with the overall aim to promote efficiency and safety of navigation, protection of environment, and safety of life at sea. Consequently, ship-borne AIS was implemented on a mandatory basis by IMO in 2000 and later amendments to chapter V of Safety of Life at Sea (SOLAS) Convention. Therefore SOLAS Convention vessels were required to carry AIS in a phased approach, from I" July 2002 to end of December 2004. The intention is to provide more precise information and a clear traffic view in navigation operations, particularly in anti-collision operation. This mandatory implementation of AIS has raised a number of issues with respect to its success in fulfilment of the intended role. In order to improve the efficiency of the AIS in navigation operation, this research mainly focused on the accuracy of AIS information, and practical use of the technology on board the ships. The intentions were to assess reliability of data, level of human failure associated with AIS, and the degree of actual use of the technology by navigators. This research firstly provided impressions about AIS technology for anti-collision operation and other marine operation and, about a system's approach to the issue of human failure in marine risk management. Secondly, this research has assessed reliability of AIS data by examination of data collected through three AIS data studies. Thirdly, it has evaluated navigators' attitude and behaviour to AIS usage by analysing the data from navigators' feedback collected through the AIS questionnaire survey focused on their perceptions about different aspects of AIS related to its use. This research revealed that some aspects of the AIS technology and some features of its users need further attention and improvement, so as to achieve its intended objectives in navigation. This study finally contributed in proposing the AIS User Satisfaction Model as a suitable framework for evaluation of navigators' satisfaction and extent of the use of AIS. This model can probably be used as the basis for measuring navigators' attitude and behaviour about other similar maritime technologies

The results of biplanar distal femoral osteotomy; a case series study

Background: Distal femur wedge osteotomies for varus or valgus alignment of the lower extremity could be done in either uniplanar or biplanar fashion. Union time and stability of the osteotomy site has been considered important in this anatomic region. In this study, clinical and radiographic findings of biplane distal femur osteotomy were reported. Methods: Clinical, functional, and radiological findings of eight patients (10 knees) underwent biplane distal femur osteotomy were evaluated. Visual analogue score (VAS) and Lysholm-Tegner knee score were used for the assessment of pain and function before and three months after surgery. Results: In this study, eight patients were included. All patients were female. The mean age was 28±6.3. The mean pre-operative mechanical angle was 8.7±2.2° and the post-operative angle was 1.4±0.53° in patients with valgus alignment whileit was 7.0±1.0°preoperatively and 0.66±1.2° postoperatively in patients with varus alignment. The mean lateral distal femoral angle (LDFA) was 85±8.0° before surgery and was 88±1.3° after surgery. According to Lysholm-Tegner knee score, in the post-operative visit, six knees were good and four were excellent. The mean union time was 9.2±2.3 weeks. Conclusions: Biplane distal femur osteotomy is a reliable technique that creates larger surfaces and more stability at the osteotomy site with further rapid union. © 2015 BY THE ARCHIVES OF BONE AND JOINT SURGERY

Accuracy of working length determination with root ZX apex locator and radiography: An in vivo and ex vivo study

The purpose of this study was to clinically compare working length (WL) determination with root ZX apex locator and radiography, and then compare them with direct visualization method ex vivo. A total of 75 maxillary central and lateral incisors were selected. Working length determination was carried out using radiographic and electronic apex locator methods. Subsequently, the tooth under study was extracted and actual working length was determined directly under a stereomicroscope. Data were analyzed by Wilcoxon signed-rank, Spearman’s correlation coefficient and intra-class correlation tests. All the statistical analyses were set with a significance level of α = 0.05. The absolute measurement errors of the two methods were compared using Wilcoxon signed test, exhibiting no statistically significant difference in measurement errors between the two methods. Descriptive evaluation revealed that in 72% (n = 54) of the specimens, both methods had errors in the same direction and in 28% (n = 21) of the specimens, the two methods had errors in opposite directions. Intra-class correlation coefficient test demonstrated a high degree of agreement between the two methods. In conclusion, this study did not show any difference between radiography, root ZX and direct visualization in WL determination.Key words: Working length, electronic apex locator, root ZX, radiography