Oxides for Rectenna Technology.

The quest to harvest untapped renewable infrared energy sources has led to significant research effort in design, fabrication and optimization of a self-biased rectenna that can operate without external bias voltage. At the heart of its design is the engineering of a high-frequency rectifier that can convert terahertz and infrared alternating current (AC) signals to usable direct current (DC). The Metal Insulator Metal (MIM) diode has been considered as one of the ideal candidates for the rectenna system. Its unparalleled ability to have a high response time is due to the fast, femtosecond tunneling process that governs current transport. This paper presents an overview of single, double and triple insulator MIM diodes that have been fabricated so far, in particular focusing on reviewing key figures of merit, such as zero-bias responsivity (ß0), zero-bias dynamic resistance (R0) and asymmetry. The two major oxide contenders for MInM diodes have been NiO and Al2O3, in combination with HfO2, Ta2O5, Nb2O5, ZnO and TiO2. The latter oxide has also been used in combination with Co3O4 and TiOx. The most advanced rectennas based on MI2M diodes have shown that optimal (ß0 and R0) can be achieved by carefully tailoring fabrication processes to control oxide stoichiometry and thicknesses to sub-nanometer accuracy.

Evaluation of the frequency and characteristics of hypercementosis in the turkish population with cone-beam computed tomography.

AIMS: The aim of this study was to evaluate the frequency and characteristics of hypercementosis in the Turkish population using cone-beam computed tomography (CBCT). SETTINGS AND DESIGN: A retrospective study was performed using CBCT (I-CAT Vision TM Imaging Science International) in 1263 patients admitted to the Faculty of Dentistry at the University of Dicle (Diyarbakir, Turkey) between January 2013 and January 2015. SUBJECTS AND METHODS: A total of 1152 patient and 29,606 teeth were evaluated with CBCT. The age, gender, location (left vs. right side, maxillary vs. mandibular teeth, incisors, premolars, and molars), and missing teeth were recorded for all patients. STATISTICAL ANALYSIS USED: The Pearson Chi-squared test was used to determine the potential differences. RESULTS: Hypercementosis was observed with a frequency of 2.4%. Of these, 18 of 28 (64.3%) had only 1 tooth with hypercementosis and 10 (35.7%) had more than 1 tooth. It was identified in 42 of the 29,606 teeth examined (0.14%). The lesion was found in 2.47% (n = 14) of females and 2.38% (n = 14) of males. The lesion was detected in 28 molars and 14 premolars, but hypercementosis was not detected in incisors. Of the 42 teeth, 12 (28.6%) maxillary and 30 (71.4%) mandibular teeth were associated with hypercementosis. Of the 28 cases, 20 (59.0%) were unilateral and 8 (41.0%) were bilateral. Of the 20 unilateral cases, 12 (69.6%) were on the right and 8 (30.4%) were on the left side. CONCLUSIONS: In our study, the prevalence of hypercementosis has been found 2.4% in the Turkish population. Besides, the lesion has been found more in the mandible than the maxilla, in the molars than the premolars and in the unilateral distribution than the bilateral distribution.

30 years of contact lens prescribing for keratoconic patients in Turkey.

PURPOSE: To assess retrospectively the course, the rate of bilateralness, prognosis, visual acuity with contact lenses, and corneal changes of a cohort with keratoconus. METHODS: Patients applying to Istanbul Faculty of Medicine, Department of Ophthalmology, Contact Lens Division during the period 1975-2005 with the diagnosis of keratoconus were recruited. The follow-up time ranged from 1.5 years to 25 years. This cohort consisted of 273 male, 245 female patients. The patients' ages ranged from 12 years to 54 years (mean age 34.8+/-10.1 years). 518 cases' 1004 eyes were divided into four groups according to their mean keratometry values. The changes in visual acuity, keratometry values and the measurements of the used contact lenses were compared with each other, and statistical significance was sought. RESULTS: By self-report, the mean starting age of keratoconus was found to be 22.5+/-7.6 years (range 7-35 years). 59 (11.4%) of 518 patients had unilateral keratoconus occurrence. The acute hydrops rate was found to be 0.3% (5 patients). In patients with advanced keratoconus, new contact lenses were applied with steeper radius of curvature. Penetrating keratoplasty was applied to 15 eyes (1.5%). Visual acuity examination on the patients' last visit, when compared to previous examinations, was found to have decreased by 2-3 Snellen lines due to advancing keratoconus. CONCLUSION: Keratoconus has shown to be a self-limited disease and in our study, with the use of contact lenses, successful outcomes which delayed the need for surgery were achieved in 98.9% of eyes (989/1004 eyes).

The role of hepatocyte growth factor in the differentiation of dendritic cells from peripheral blood monocytes.

OBJECTIVE: To find out the effects of hepatocyte growth factor (HGF) in the development of dendritic cells (DC) from the peripheral monocytes. METHODS: The study was carried out in Black Sea Technical University Hospital, Trabzon, Turkey between 2003-2004. Seven different cytokine combinations were employed to assess phenotypical and functional differences of DCs from the peripheral monocytes in serum free culture media. Peripheral monocytes were incubated in media with cytokines for 5 days. The tumor necrosis factor-alpha (TNF-alpha) was added to the cell culture on day 5 and incubated for another 2 days. Surface and co-stimulating molecules on the cells were assessed by flowcytometry. The functional capacity of the DCs was evaluated on day 7 by purified protein derivative loading and subsequent lymphoproliferation test using methyl tetrazolium staining. RESULTS: On the 5th day of incubation DC development was observed in all cytokine groups, but cells were superior in cultures maintained in the presence of interleukin-4 combinations with granulocyte-macrophage colony stimulating factor (GM-CSF) or with GM-CSF+HGF. Moreover, the expression of surface and co-stimulating molecules increased significantly after incubation with TNF-alpha. The effect of PPD loaded-DCs on proliferation of lymphocytes was more striking in HGF containing groups. CONCLUSION: It was concluded that HGF supplemented cultures exert some additive effects in relation to function of monocyte-derived DCs. But HGF alone does not seem to augment monocyte-derived DC proliferation and maturation significantly.

Mesenchymal stem cells in iatrogenic facial nerve paralysis: a possible role in the future.

Iatrogenic facial nerve paralysis is one of the major and drastic complications of ear surgery. We report a case of a 20-year-old female patient with simple chronic otitis media who underwent mastoidectomy and tympanoplasty. During the mastoidectomy process the facial nerve was unintentionally destroyed, leaving a gap of 8-10 mm in the third segment of the intratemporal facial nerve. The nerve was repaired with a nerve cable graft obtained from the vicinity. On the 42nd day, autologous mesenchymal stem cell transplantation was performed after facial nerve trauma. The patient's facial nerve paralysis has recovered from House-Brackmann grade VI to IV within a week and then to III in the fifth month. The rapid, postoperative progress, and the early follow-up results are discussed. This case represents the first bone marrow stem cell application in a peripheral nerve, namely the facial nerve.

Predictors of occupational exposure to styrene and styrene-7,8-oxide in the reinforced plastics industry.

OBJECTIVE: To identify demographic and work related factors that predict blood levels of styrene and styrene-7,8-oxide (SO) in the fibreglass reinforced plastics (FRP) industry. METHODS: Personal breathing-zone air samples and whole blood samples were collected repeatedly from 328 reinforced plastics workers in the Unuted States between 1996 and 1999. Styrene and its major metabolite SO were measured in these samples. Multivariable linear regression analyses were applied to the subject-specific levels to explain the variation in exposure and biomarker levels. RESULTS: Exposure levels of styrene were approximately 500-fold higher than those of SO. Exposure levels of styrene and SO varied greatly among the types of products manufactured, with an 11-fold range of median air levels among categories for styrene and a 23-fold range for SO. Even after stratification by job title, median exposures of styrene and SO among laminators varied 14- and 31-fold across product categories. Furthermore, the relative proportions of exposures to styrene and SO varied among product categories. Multivariable regression analyses explained 70% and 63% of the variation in air levels of styrene and SO, respectively, and 72% and 34% of the variation in blood levels of styrene and SO, respectively. Overall, air levels of styrene and SO appear to have decreased substantially in this industry over the last 10-20 years in the US and were greatest among workers with the least seniority. CONCLUSIONS: As levels of styrene and SO in air and blood varied among product categories in the FRP industry, use of job title as a surrogate for exposure can introduce unpredictable measurement errors and can confound the relation between exposure and health outcomes in epidemiology studies. Also, inverse relations between the intensity of exposure to styrene and SO and years on the job suggest that younger workers with little seniority are typically exposed to higher levels of styrene and SO than their coworkers.

Autologous peripheral stem cell transplantation in patients with congestive heart failure due to ischemic heart disease.

OBJECTIVE: Ischemic heart disease accounts for 50% of all cardiovascular deaths and is the leading cause of congestive heart failure. Medical therapy, cardiac assist devices and surgical procedures including heart transplantation have limited efficiency and availability. Stem cell transplantation represents a new therapeutic opportunity for such patients. METHOD: Six patients with the diagnosis of ischemic cardiomyopathy were included in this study. All of the patients had clinical, radiological and echocardiographic signs of heart failure, and reduced left ventricular ejection fraction (LVEF< or =25%). They underwent coronary angiography and stress tests with dobutamine echocardiography, thallium scintigraphy and positron emission tomography to assess myocardial ischemia and viability. Peripheral stem cells were mobilized and collected by apheresis. They were transplanted into areas of injury with open-heart surgery. To increase blood flow to the engrafted areas, coronary artery by-pass surgery was also performed. RESULTS: The patients were followed at least for 4 months. Echocardiography, thallium scintigraphy and positron emission tomography were repeated after at least 6 weeks following surgery. There was a significant increase in life quality and NYHA class. Some benefit was documented on echocardiography, thallium scintigraphy, and positron emission tomography. CONCLUSION: This approach opens a new window in the treatment of 'no hope' patients with congestive heart failure.

Health care systems in transition: Turkey

The Health Systems in Transition (HiT) series provide detailed descriptions of health systems in the countries of the WHO European Region as well as some additional OECD countries. An individual health system review (HiT) examines the specific approach to the organization, financing and delivery of health services in a particular country and the role of the main actors in the health system. It describes the institutional framework, process, content, and implementation of health and health care policies. HiTs also look at reforms in progress or under development and make an assessment of the health system based on stated objectives and outcomes with respect to various dimensions (health status, equity, quality, efficiency, accountability).

MACH : a methodology for analysing contracting in health care

A central theme underlying the proposals for reform of health systems worldwide is the introduction of market incentives. In the United Kingdom, the experience of an internal market with the separation of functions between purchasers and providers and the use of contracts, has been followed with interest by many governments. In countries such as Germany, separation of functions and contracting negotiations have been the norm for many decades. In the countries of central and eastern Europe and the newly independent states, the implementation of contracting is being considered in many reform proposals. This study suggests that there is a need to improve the understanding of contracting, its links with health policy, and the functions and characteristics of contracts, and proposes a methodology for analysing contracting in health care (MACH). Focusing on the context, the contracting process and on management of change for the development of contracting, the study applies the MACH to the experience of Germany and the United Kingdom. In Kyrgyzstan, where contracting mechanisms have not yet been implemented, the study uses the MACH for disucssing proposals for the development of contracting. Some of the strengths and weaknesses of the MACH identified during its application are discussed, major conclusions about contracting are presented and, in the light of the lessons learnt from the application of the methodology, recommendations for the development of contracting in Kyrgyzstan are made