Growth of graphene on cylindrical copper conductors as an anticorrosion coating: a microscopic study.

We have successfully grown graphene film on the surface of cylindrical copper conductors by chemical vapour deposition. The quality and number of graphene layers have been investigated using Raman spectroscopy, Raman mapping and scanning electron microscopy, as a function of methane gas flow rate and of growth temperature. Transmission electron microscopy analysis has been performed to verify the number of graphene layers, confirming the results obtained by Raman spectroscopy. The results open up the possibility of using graphene as an anticorrosion coating for copper cables and earth grids.

Spin-relaxation anisotropy in a GaAs quantum dot.

We report that the electron spin-relaxation time T_{1} in a GaAs quantum dot with a spin-1/2 ground state has a 180° periodicity in the orientation of the in-plane magnetic field. This periodicity has been predicted for circular dots as being due to the interplay of Rashba and Dresselhaus spin orbit contributions. Different from this prediction, we find that the extrema in the T_{1} do not occur when the magnetic field is along the [110] and [11[over ¯]0] crystallographic directions. This deviation is attributed to an elliptical dot confining potential. The T_{1} varies by more than 1 order of magnitude when rotating a 3 T field, reaching about 80 ms for the optimal angle. We infer from the data that in our device the signs of the Rashba and Dresselhaus constants are opposite.

Feasibility study of plasma pyrolysis on dairy waste.

Considering the ever-increasing necessity of the disposal of industrial and household waste and using mechanisms through which the utmost potential of the waste is directed to the efficient recycling of materials or forms of energy, the current study aims to investigate plasma pyrolysis as an eco-friendly and appropriate approach that leads to the production of value-added products. The novelty of this study lies in its development of a method for spoiled milk disposal since no efficient solution has been provided yet in this respect. The other benefit of implementing the proposed disposal method is the production of high-quality syngas. The maximum produced hydrogen percentage and syngas rate during the process under study in this research were obtained as 60.396 % and 2.166, respectively. A plasma method is a rare approach to yielding products with such values. The obtained results revealed that the transferred thermal plasma could efficiently dispose of the spoiled milk waste and be used as a novel approach to the green synthesis of hydrogen through plasma pyrolysis.

Resolving spin-orbit- and hyperfine-mediated electric dipole spin resonance in a quantum dot.

We investigate the electric manipulation of a single-electron spin in a single gate-defined quantum dot. We observe that so-far neglected differences between the hyperfine- and spin-orbit-mediated electric dipole spin resonance conditions have important consequences at high magnetic fields. In experiments using adiabatic rapid passage to invert the electron spin, we observe an unusually wide and asymmetric response as a function of the magnetic field. Simulations support the interpretation of the line shape in terms of four different resonance conditions. These findings may lead to isotope-selective control of dynamic nuclear polarization in quantum dots.

Simultaneous spin-charge relaxation in double quantum dots.

We investigate phonon-induced spin and charge relaxation mediated by spin-orbit and hyperfine interactions for a single electron confined within a double quantum dot. A simple toy model incorporating both direct decay to the ground state of the double dot and indirect decay via an intermediate excited state yields an electron spin relaxation rate that varies nonmonotonically with the detuning between the dots. We confirm this model with experiments performed on a GaAs double dot, demonstrating that the relaxation rate exhibits the expected detuning dependence and can be electrically tuned over several orders of magnitude. Our analysis suggests that spin-orbit mediated relaxation via phonons serves as the dominant mechanism through which the double-dot electron spin-flip rate varies with detuning.

The effect of PRP and hyperosmolarity simultaneous use on expression profile alteration of miRNAs associated with cartilage differentiation in human adipose tissue-derived mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cells (MSC) are a type of multipotent stem cell whose differentiation into cartilage cells has been considered in recent years. Platelet-rich plasma (PRP) may impair cartilage differentiation due to its richness in growth factors and hyperosmolarity due to its proximity to the required cartilage environment. OBJECTIVES: The main purpose of this study was to treat human adipose tissue-derived MSCs concurrently with PRP and hyperosmolarity to investigate the expression profile of micro-RNA (miRNA) involved in the cartilage process differentiation. We examined the effect of PRP and the increase in osmolarity on the expression of miR-27, miR-101, miR-140, miR-145, miR-146, and miR-199. METHODS: Mesenchymal stem cells were extracted from human adipose tissue and differentiated into chondrocytes and the effect of baseline cultures (diff), PRP (prp), hyperosmolarity (os), base plus hyperosmolarity (diff + os), PRP plus hyperosmolarity (prp + os) next to the control group were studied in cartilage differentiation using specific stains such as Alcian blue, hematoxylin and eosin, and collagen type 2 and 10 immunohistochemistry. In addition, the expression of miR-27, miR-140, miR-199, miR-146, miR-101, and miR-145 was evaluated using real-time PCR. CONCLUSION: Human adipose tissue-derived MSCs with the ability to differentiate into adipocytes and osteocytes showed the properties of chondrocytes in all differentiation groups. Alkaline phosphatase (ALP) enzyme activity and calcium deposition were lower in the diff + os group than in other groups. Therefore, the diff + os group may be a more suitable environment for cartilage differentiation. Furthermore, 5% PRP concentration and hyperosmolarity showed a positive effect on miR-140, miR-199, miR-27, and, miR-146 and a negative effect on miR-101 and miR-145 on cartilage differentiation.

Lipid-lowering effect of Rhus coriaria L. (sumac) fruit extract in hypercholesterolemic rats.

Hyperlipidemia is a major risk factor for development of atherosclerosis. In the present study, the hypolipidemic effects of sumac (Rhus coriaria L.) fruits in high cholesterold diet (HCD)-fed rats was investigated. There was a significant (p < 0.001) increase in the levels of total cholesterol (TC) and triglycerides (TG) along with augmented activities of serum aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase. Treatment with aqueous methanol extract of sumac fruits reduced the above alterations observed in hypercholesterolemic rats. Sumac extract also reversed the hypertrophic cardiac histology. Furthermore, in vivo toxicological studies showed no evidence of acute toxicity of the extract in male Wistar rats. In conclusion, sumac fruit extract intervention minimized the lipid abnormalities and abnormal biochemical changes induced in HCD fed rats. This shows that sumac fruit extract possesses cardioprotective and hepatoprotective activities which will be beneficial in hypercholesterolemic condition.

Risk factors and control strategies for silicotuberculosis as an occupational disease.

Silicotuberculosis is critical in community settings among workers and employees exposed to silica dust. Older age of entry (>30 years), male sex, infection with human immunodeficiency virus (HIV), exposure duration, smoking, chronic obstructive pulmonary disease, migration, the severity of the silicosis and the intensity of the exposure are potential risk factors. Lack of timely diagnosis and treatment for tuberculosis (TB) may also raise the rate of infection; previous treatment of TB is possibly associated with the development of silicotuberculosis in more than half of patients, increasing with age (>40 years). Identification of risk factors benefits not only the academic research community, but also the workers or employees and policy making. Some strategies can be implemented, such as controlling or reducing exposure to silica dust, ensuring continuity of treatment of TB or extended anti-TB treatment, management of the situation by occupational health professionals, prevention of oscillating migration, providing workers with compensation, training and education in occupational health, improving the quality of life of miners and workers, intensive medical surveillance and TB screening in routine health check ups, and policy making for higher immunity to inhibit inhalation of dust by workers or employees.

Reperfusion injury and inflammatory responses following acute lower limb revascularization surgery.

After revascularization of an acute arterial occlusion the development of a serious ischaemic-reperfusion injury is a menacing challenge and a hard task in peripheral vascular surgery. A whale of evidences point to oxidative stress, as an important trigger, in the complex chain of events leading to reperfusion injury. In the present study authors aimed to examine oxidative stress parameters, antioxidant-prooxidant state and leukocyte adhesion molecules (CD11a and CD18) expression following acute revascularization surgery of lower limb.10 patients were examined in the prospective randomized study. Peripheral blood sample was collected in ischaemic period, and after reperfusion in the 2nd and 24th hours, and on 7th day. Superoxide-dismutase activity, reduced glutathion concentration and leukocytes free radical production were measured. The degree of lipidperoxidation was marked with the quantity of malondialdehyde. The expressions of adhesion molecules were measured with flowcytometry.The speed and rate of free radical production significantly increased in the early reperfusion (p<0.05). The level of antioxidant enzymes decreased after revascularization. The CD11a and CD18 expression of the granulocytes significantly (p<0.05) decreased right after the revascularization, but with a gradual elevation until the 7th day they exceed the ischaemic value. Our results showed a time specific turnover of the sensitive antioxidant-prooxidant balance after revascularization operation.

Ischaemic postconditioning reduces peroxide formation, cytokine expression and leukocyte activation in reperfusion injury after abdominal aortic surgery in rat model.

OBJECTIVE: We studied the protective effects of ischaemic postconditioning (PS) on ischemia-reperfusion injury of the lower extremities in a rat model of abdominal aortic intervention. We aimed to examine the evoked oxidative stress, cytokine expression and leukocyte activation after revascularisation surgery. METHODS: Anesthetized animals (48 Whistar rats) underwent a 60 min infrarenal aorta cross-clamping. After the ischaemic period, an intermittent 4 times 15 s reperfusion--15 seconds ischaemic episodes--were applied (ischaemic postconditioning: group PS). Then we started a 120 min reperfusion in the aorta. In untreated group animals underwent a long ischaemia (60 min) and the following reperfusion (group IR). Peripherial blood samples were collected before operation, and in early (5, 10, 15, 30, 60 and 120 min) reperfusion periods. Serum peroxide level, TNF-alpha concentration, myeloperoxidase (MPO) activity and PMA-induced leukocyte ROS production were measured. RESULTS: In PS group, plasma peroxide level elevation was significantly lower in very early reperfusion (5-30 min) comparing to non-conditioned IR group (10.04+/-1.9 microM/l vs. 16.91+/-3.67 microM/l, p<0.05). PS also reduced serum TNF-alpha concentration (167.41+/-31.26 microg/ml vs. 116.55+/-12.04 microg/ml, p<0.05), MPO activity (1.759+/-0.239 microM/ml vs. 1.22+/-0.126 microM/ml, p<0.05) and leukocyte activation detected by PMA-induced leukocyte ROS production (5.7+/-0.96 AU/10(3) cells vs. 4.63+/-0.69 AU/10(3) cells). CONCLUSIONS: Ischaemic postconditioning could reduce ROI production after IR in early reperfusion period, thus limiting ROI mediated tissue lesion, cytokine-leukocyte activation and inflammatory responses. PS seems to be an effective tool in vascular surgery to reduce reperfusion injuries after revascularization interventions.

Confirmation of hydrazone formation in HYNIC-peptide conjugate preparation, and its hydrolysis during labeling with (99m)Tc.

Because of its monodenticity, 6-hydrazinopyridine-3-carboxylic acid (HYNIC) is of interest as a bifunctional chelator for labeling peptide with (99m)Tc. Here, we confirm the formation of hydrazone in HYNIC-conjugated peptide. The preparative HPLC was used to purify the HYNIC conjugated somatostatin-based peptide and the result showed two peaks, even after two consecutive purifications. Analysis of these peaks by mass spectrometry indicated the presence of hydrazone, produced during preparation conjugate. Further, we have shown that presence of hydrazone really does not matter because under (99m)Tc-labeling conditions, hydrazone is hydrolyzed back to HYNIC that then chelates (99m)Tc. A HYNIC-peptide conjugate freeze-dried kit was also prepared in a mildly acidic or neutral condition with a final pH of 6-7. The kit was then labeled by (99m)Tc and incubated in 100 degrees C for 10min, and a labeling yield of >95% was obtained.

The Parametric Study and Fine-Tuning of Bow-Tie Slot Antenna with Loaded Stub.

A printed Bow-Tie slot antenna with loaded stub is proposed and the effects of changing the dimensions of the slot area, the stub and load sizes are considered in this paper. These parameters have a considerable effect on the antenna characteristics as well as its performance. An in-depth parametric study of these dimensions is presented. This paper proposes the necessary conditions for initial approximation of dimensions needed to design this antenna. In order to achieve the desired performance of the antenna fine tuning of all sizes of these parameters is required. The parametric studies used in this paper provide proper trends for initiation and tuning the design. A prototype of the antenna for 1.7GHz to 2.6GHz band is fabricated. Measurements conducted verify that the designed antenna has wideband characteristics with 50% bandwidth around the center frequency of 2.1GHz. Conducted measurements for reflection coefficient (S11) and radiation pattern also validate our simulation results.

Effects of low-powered RF sweep between 0.01-20 GHz on female Aedes Aegypti mosquitoes: A collective behaviour analysis.

There are many products claiming to be an electronic solution towards repelling mosquitoes. Several reviews were published in debunking these claims. However, there is a lack of a systematic study on effects of electromagnetic (EM) or more specifically, radio frequency (RF) waves against mosquitoes due to the conclusions made in those years. Therefore, we attempt to establish a fundamental study on female Aedes Aegypti (Linnaeus) mosquitoes by quantifying the collective behavior of the mosquitoes against a continuous stream of low-powered RF signals via a broadband horn antenna using image processing methods. By examining the average lateral and vertical positions of the mosquitoes versus frequency and time, the data shows negligible consistency in the reactions of the mosquitoes toward the different frequencies ranging from 10 to 20,000.00 MHz, with a step of 10 MHz. This was done by examining 33 hours of spatiotemporal data, which was divided into three sessions. All three sessions showed totally different convolutions in the positions in arbitrary units based on the raster scan of the image processing output. Several frequencies apparently showed up to 0.2-70% shift in both lateral and vertical components along the spectrum, without repeatability for all three sessions. This study contributes to the following: A pilot study for establishing the collective effects of RF against mosquitoes, open-source use, and finally a low-cost and easily adaptable platform for the study of EM effects against any insects.

Single-spin CCD.

Spin-based electronics or spintronics relies on the ability to store, transport and manipulate electron spin polarization with great precision. In its ultimate limit, information is stored in the spin state of a single electron, at which point quantum information processing also becomes a possibility. Here, we demonstrate the manipulation, transport and readout of individual electron spins in a linear array of three semiconductor quantum dots. First, we demonstrate single-shot readout of three spins with fidelities of 97% on average, using an approach analogous to the operation of a charge-coupled device (CCD). Next, we perform site-selective control of the three spins, thereby writing the content of each pixel of this 'single-spin charge-coupled device'. Finally, we show that shuttling an electron back and forth in the array hundreds of times, covering a cumulative distance of 80 µm, has negligible influence on its spin projection. Extrapolating these results to the case of much larger arrays points at a diverse range of potential applications, from quantum information to imaging and sensing.

Histochemical assessment of nitric oxide synthase activity in aortic endothelial cells of streptozotocin-induced diabetic rats.

Impaired endothelium-dependent relaxation of blood vessels is a common feature in diabetes, but the exact underlying mechanisms have not yet been clarified. In present study, endothelium-dependent vasorelaxation of aortic rings were evaluated in vitro in streptozotocin (STZ)-induced diabetic and age-matched control rats. Moreover, nitric oxide synthase (NOS) activity of aortic endothelial cells was assessed in both diabetic and healthy rats using histochemical staining for nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity. The results showed a significant decrease of endothelium-dependent relaxation in response to acetylcholine (ACh) in diabetic rings, compared with controls, that was accompanied by a remarkable attenuation of NOS activity in diabetic sections of rat aorta stained for NADPH-diaphorase. Furthermore, a membrane disruption of some endothelial cells was also observed in all diabetic sections. It can be concluded that a decrease in NOS activity together with a disruption of endothelial cell membrane play a major role in endothelial dysfunction observed in diabetes.

Robust stabilization of uncertain nonlinear slowly-varying systems: application in a time-varying inertia pendulum.

This paper considers the problem of robust stabilization of nonlinear slowly-varying systems, in the presence of model uncertainties and external disturbances. The main contribution of this paper is an extension of the Slowly-Varying Control Lyapunov Function (SVCLF) technique to design a robust stabilizing controller for nonlinear slowly-varying systems with matched uncertainties. In the proposed strategy, the Lyapunov redesign method is utilized to design a robust control law. This method, originally, leads to a discontinuous controller which suffers from chattering. In this paper, this problem is removed by using a saturation function with a high slope, as an approximation of the signum function. Since, using the saturation function leads to loss of asymptotic stability and, instead, guarantees only the boundedness of the system's states; therefore, some sufficient conditions are proposed to guarantee the asymptotic stability of the closed-loop uncertain nonlinear slowly-varying system (without chattering). Also, in order to show the applicability of the proposed method, it is applied to a time-varying inertia pendulum. The efficiency of the designed controller is demonstrated through analysis and simulations.

Application of partial sliding mode in guidance problem.

In this paper, the problem of 3-dimensional guidance law design is considered and a new guidance law based on partial sliding mode technique is presented. The approach is based on the classification of the state variables within the guidance system dynamics with respect to their required stabilization properties. In the proposed law by using a partial sliding mode technique, only trajectories of a part of states variables are forced to reach the partial sliding surfaces and slide on them. The resulting guidance law enables the missile to intercept highly maneuvering targets within a finite interception time. Effectiveness of the proposed guidance law is demonstrated through analysis and simulations.

Partial stabilization-based guidance.

A novel nonlinear missile guidance law against maneuvering targets is designed based on the principles of partial stability. It is demonstrated that in a real approach which is adopted with actual situations, each state of the guidance system must have a special behavior and asymptotic stability or exponential stability of all states is not realistic. Thus, a new guidance law is developed based on the partial stability theorem in such a way that the behaviors of states in the closed-loop system are in conformity with a real guidance scenario that leads to collision. The performance of the proposed guidance law in terms of interception time and control effort is compared with the sliding mode guidance law by means of numerical simulations.

Two-year experience of orthotopic liver transplantation in afzalipoor hospital, kerman, southeastern iran.

BACKGROUND: End-stage liver diseases are common in Iran. The only therapeutic option for these patients is liver transplantation. OBJECTIVE: To present our 2-year experience of liver transplantations in Afzalipoor Hospital, Kerman, southeastern Iran. METHODS: From November 2009 to September 2011, 12 patients underwent orthotopic liver transplantation in our center. Their data including demographics, indications for transplantation, MELD scores, post-operative complications and their management were collected. RESULTS: Patients (7 women and 5 men) aged between 14 and 55 years. Indications for the transplantation included HBV infection (n=5), cryptogenic cirrhosis (n=2), Wilson's disease, alcoholism (n=1), HCV infection (n=1), Budd-Chiari syndrome (n=1), and autoimmune hepatitis (n=1). MELD score of patients ranged from 16 to 30. All patients received tacrolimus, mycophenolate mofetile and corticosteroid, postoperatively. 2 patients died of pulmonary and intra-abdominal infections with resultant to multiple organ failure. Nonfunctioning of transplanted liver and ongoing bleeding resulted in death in another patients. 9 patients are well doing and have excellent liver functions. CONCLUSION: We had relatively successful results in our experience of orthotopic liver transplantation. Vicinity of our center to Shiraz Transplant Center would be an important factor in this success.

Influence of magnetic field on the electric breakdown in penning ion source.

A cold-cathode penning-type ion source has been developed in our laboratory to study the electric breakdown in this type of sources. The breakdown voltage was measured as a function of axial magnetic field, in the range of 440-600 G, and anode length, in steps of 14, 20, and 24 mm. The measurement was performed with stainless steel cathodes in argon gas at pressure of 4 × 10(-2) mbar. Furthermore, a model was developed to explain the breakdown voltage data. In the construction of the model, the first Townsend coefficient was not directly used to avoid difficulties originating from the non-uniformity of the electric field. The empirical parameters of the model were obtained using the experimental data. The equation γ = c × (E(z)/N)(n), expressing the effective secondary emission coefficient in terms of reduced electric field, which was needed in the modeling process, was inspired from previous works. The parameters c and n were then calculated from the empirical parameters of the model. The n parameter turned out to be 0.59, which differs from the value reported by other authors merely by 1.6%. Three values, 0.010, 0.013, and 0.017 corresponding to the three anodes were obtained for the c parameter. These numbers are in good agreement with 0.01, which has been reported in the previous works. It was also found that the value of n has a decisive impact on the breakdown voltage curve in the high breakdown voltage region.