New heat treatment to prepare high quality polycrystalline and single crystal MgB2 in single process

We report here on a new heat treatment to prepare both dense polycrystalline and single crystal MgB2 high quality samples in one single process. Resistivity measurements for polycrystalline part of the sample gives a residual resistivity ratio RRR=16.6 and a very low normal state resistivity rho(40K)= 0.28 microOhmcm. Both SEM and SQUID study on polycrystals reveal the high quality, dense character and well coupling of grain boundaries. On the other hand, the high quality single crystals have a unique shape that resembles the hexagonal crystal structure. SQUID measurements reveals very weak flux pinning character implying our single crystals to be very clean. In this study, we conclude that heat treatment is playing a major rule on the characteristics of both polycrystalline and single crystal MgB2. Samples are thoroughly characterized by x-ray, resistivity, dc SQUID and SEM

Power System Stabilizer Driven by an Adaptive Fuzzy Set for Better Dynamic Performance

This paper presents a novel application of a fuzzy logic controller (FLC) driven by an adaptive fuzzy set (AFS) for a power system stabilizer (PSS).The proposed FLC, driven by AFS, is compared with a classical FLC, driven by a fixed fuzzy set (FFS). Both FLC algorithms use the speed error and its rate of change as input vectors. A single generator equipped with FLC-PSS and connected to an infinite bus bar through double transmission lines is considered. Both FLCs, using AFS and FFS, are simulated and tested when the system is subjected to different step changes in the reference value. The simulation results of the proposed FLC, using the adaptive fuzzy set, give a better dynamic response of the overall system by improving the damping coefficient and decreasing the rise time and settling time compared with classical FLC using FFS. The proposed FLC using AFS also reduces the computational time of the FLC as the number of rules is reduced.

Hepatocellular proliferation in response to agonists of peroxisome proliferator-activated receptor alpha: a role for kupffer cells?

BACKGROUND: It has been proposed that PPARα agonists stimulate Kupffer cells in rodents which in turn, release mitogenic factors leading to hepatic hyperplasia, and eventually cancer. However, Kupffer cells do not express PPARα receptors, and PPARα agonists stimulate hepatocellular proliferation in both TNFα- and TNFα receptor-null mice, casting doubt on the involvement of Kupffer cells in the mitogenic response to PPARα agonists. This study was therefore designed to investigate whether the PPARα agonist PFOA and the Kupffer cell inhibitor methylpalmitate produce opposing effects on hepatocellular proliferation and Kupffer cell activity in vivo, in a manner that would implicate these cells in the mitogenic effects of PPARα agonists. METHODS: Male Sprague-Dawley rats were treated intravenously via the tail vein with methylpalmitate 24 hrs prior to perfluorooctanoic acid (PFOA), and were sacrificed 24 hrs later, one hr after an intraperitoneal injection of bromodeoxyuridine (BrdU). Sera were analyzed for TNFα and IL-1β. Liver sections were stained immunohistochemically and quantified for BrdU incorporated into DNA. RESULTS: Data show that PFOA remarkably stimulated hepatocellular proliferation in the absence of significant changes in the serum levels of either TNFα or IL-1β. In addition, methylpalmitate did not alter the levels of these mitogens in PFOA-treated animals, despite the fact that it significantly blocked the hepatocellular proliferative effect of PFOA. Correlation between hepatocellular proliferation and serum levels of TNFα or IL-1β was extremely poor. CONCLUSION: It is unlikely that mechanisms involving Kupffer cells play an eminent role in the hepatic hyperplasia, and consequently hepatocarcinogenicity attributed to PPARα agonists. This conclusion is based on the above mentioned published data and the current findings showing animals treated with PFOA alone or in combination with methylpalmitate to have similar levels of serum TNFα and IL-1β, which are reliable indicators of Kupffer cell activity, despite a remarkable difference in hepatocellular proliferation

Fuzzy Algorithm for Supervisory Voltage/Frequency Control of a Self Excited Induction Generator

This paper presents the application of a Fuzzy Logic Controller (FLC) to regulate the voltage of a Self Excited Induction Generator (SEIG) driven by Wind Energy Conversion Schemes (WECS). The proposed FLC is used to tune the integral gain (KI) of a Proportional plus Integral (PI) controller. Two types of controls, for the generator and for the wind turbine, using a FLC algorithm, are introduced in this paper. The voltage control is performed to adapt the terminal voltage via self excitation. The frequency control is conducted to adjust the stator frequency through tuning the pitch angle of the WECS blades. Both controllers utilize the Fuzzy technique to enhance the overall dynamic performance.  The simulation result depicts a better dynamic response for the system under study during the starting period, and the load variation. The percentage overshoot, rising time and oscillation are better with the fuzzy controller than with the PI controller type.

Dentists\u27 Attitudes Towards Chairside Medical Conditions Screening in a Dental Setting in Saudi Arabia: An Exploratory Cross-Sectional Study.

BACKGROUND: Screening for medical conditions (MCs) of public health importance is a first step in disease prevention and control. Prior studies in the United States found oral health care providers (OHCPS) embrace screening for increased risk of medical conditions in the dental setting. Our objectives were to assess Saudi Arabian (SA) dentist\u27s attitudes, willingness and perceived barriers towards implementing screening for MCs into their dental practices. METHODS: A self-administered, 5-point Likert Scale (1 = very important/willing to 5 = very unimportant/unwilling) questionnaire was given to a convenience sample of 190 practicing dentists. Friedman nonparametric analysis of variance was used to compare responses within each question. RESULTS: Of the 143 responding dentists the mean age was 31 years; 102 (71%) were men. The majority felt it was important for a dentist to screen for cardiovascular disease (98.6%), hypertension (97.9%), diabetes (97.9%), human immunodeficiency virus (HIV) (97.9%), and hepatitis C virus (98.6%). Respondents were willing to refer a patient to a physician (97.9%); send samples to an outside laboratory (96.1%); conduct screening that yields immediate results (96.2%); and discuss results immediately with the patient (93.7%). Respondents were willing to measure/collect blood pressure (67.2%); weight and height (63.7%); and finger stick blood (54.6%). The whole responding dentists (100%) reported time as an important barrier. Respondents were significantly more willing to refer a patient for consultation than send samples to an outside laboratory (mean ranks: 2.32, 2.81, P \u3c 0.001); significantly more willing to measure blood pressure than take oral fluids for salivary diagnostics (mean ranks 2.22, 2.75, p = 0.003). Insurance was significantly (P \u3c 0.05) less important barrier than time, cost, patients\u27 willingness or liability (mean ranks 3.56, 2.63, 3.00, 2.79, 3.02, respectively). CONCLUSIONS: The majority of dentists in this study reported positive attitudes towards and willingness to perform medical screenings in their practice. Time was an important factor

Dentists\u27 Attitudes Towards Chairside Medical Conditions Screening in a Dental Setting in Saudi Arabia: An Exploratory Cross-Sectional Study

BACKGROUND: Screening for medical conditions (MCs) of public health importance is a first step in disease prevention and control. Prior studies in the United States found oral health care providers (OHCPS) embrace screening for increased risk of medical conditions in the dental setting. Our objectives were to assess Saudi Arabian (SA) dentist\u27s attitudes, willingness and perceived barriers towards implementing screening for MCs into their dental practices. METHODS: A self-administered, 5-point Likert Scale (1 = very important/willing to 5 = very unimportant/unwilling) questionnaire was given to a convenience sample of 190 practicing dentists. Friedman nonparametric analysis of variance was used to compare responses within each question. RESULTS: Of the 143 responding dentists the mean age was 31 years; 102 (71%) were men. The majority felt it was important for a dentist to screen for cardiovascular disease (98.6%), hypertension (97.9%), diabetes (97.9%), human immunodeficiency virus (HIV) (97.9%), and hepatitis C virus (98.6%). Respondents were willing to refer a patient to a physician (97.9%); send samples to an outside laboratory (96.1%); conduct screening that yields immediate results (96.2%); and discuss results immediately with the patient (93.7%). Respondents were willing to measure/collect blood pressure (67.2%); weight and height (63.7%); and finger stick blood (54.6%). The whole responding dentists (100%) reported time as an important barrier. Respondents were significantly more willing to refer a patient for consultation than send samples to an outside laboratory (mean ranks: 2.32, 2.81, P \u3c 0.001); significantly more willing to measure blood pressure than take oral fluids for salivary diagnostics (mean ranks 2.22, 2.75, p = 0.003). Insurance was significantly (P \u3c 0.05) less important barrier than time, cost, patients\u27 willingness or liability (mean ranks 3.56, 2.63, 3.00, 2.79, 3.02, respectively). CONCLUSIONS: The majority of dentists in this study reported positive attitudes towards and willingness to perform medical screenings in their practice. Time was an important factor

Analytical modeling for the heat transfer in sheared flows of nanofluids

We developed a model for the enhancement of the heat flux by spherical and elongated nano- particles in sheared laminar flows of nano-fluids. Besides the heat flux carried by the nanoparticles the model accounts for the contribution of their rotation to the heat flux inside and outside the particles. The rotation of the nanoparticles has a twofold effect, it induces a fluid advection around the particle and it strongly influences the statistical distribution of particle orientations. These dynamical effects, which were not included in existing thermal models, are responsible for changing the thermal properties of flowing fluids as compared to quiescent fluids. The proposed model is strongly supported by extensive numerical simulations, demonstrating a potential increase of the heat flux far beyond the Maxwell-Garnet limit for the spherical nanoparticles. The road ahead which should lead towards robust predictive models of heat flux enhancement is discussed.Comment: 14 pages, 10 figures, submitted to PR

Glucocorticoid-like effects of antihepatocarcinogen Rotenone are mediated via enhanced serum corticosterone levels: Molecular Fitting and Receptor Activation Studies

BACKGROUND: Recent studies suggest that rotenone alters cell signal transduction pathways in a manner similar to glucocorticoids. Histological and biochemical markers of glucocorticoid effects in vivo, evaluated in our laboratories, provide further evidence for similarities in the activity of glucocorticoids and rotenone. The purpose of this study was to investigate the mechanism by which rotenone produces glucocorticoid-like effects. METHODS: Male B6C3F1 mice were treated for 7 days with rotenone (600 ppm in diet), the glucocorticoid antagonist RU486 (2 mg/kg/day, ip), corticosterone (2 mg/kg/day, ip), or both rotenone and RU 486. Control mice received drug-free diet and the vehicle (corn oil, ip). Following preservation in 10% neutral buffered formalin, tissues were embedded in paraffin. Sections were stained with hematoxylin, eosin, and were examined by light microscopy. Tissue sections were processed for in situ enzymatic end labeling of 3'-hydroxy-DNA strand breaks, a measure of apoptosis. Corticosterone was quantified in sera, using a solid phase radioimmunoassay kit. Cells (cell line 1470.2 derived from C127 mouse mammary adenocarcinoma cells) were transiently transfected with 5 μg of pLTRLuc and 1 μg of β-Galactosidase expression vectors using a BTX square-wave pulser at 155 V, 4 pulses (40 ms each). Cells were then treated with dexamethasone, rotenone, or a mixture of both for 6 hr, harvested and assayed for luciferase and β-Galactosidase activity. Using Root Mean Square (RMS) fit analysis (Alchemy™, Tripose, Inc., St Louis, MO), we assessed possible structural similarities between rotenone and corticosterone, dehydrocorticosterone, glucocorticoid antagonists ZK 98.299, and RU 486. RMS fit was calculated by selecting three atoms in each of the molecules, followed by calculating the distance between these atoms. An RMS value of zero between two molecules indicates identical molecular characteristics. A positive value suggests diminished similarity with a value of 1 or higher excluding any such similarities. RESULTS: Although the stimulatory effect exerted by rotenone on hepatocellular apoptosis was in the opposite direction of that produced by the glucocorticoid antagonist RU 486, data suggested that rotenone does not directly activate the glucocorticoid receptor. Molecular fitting of rotenone to glucocorticoid receptor agonists and antagonists as well as examination of the transcriptional activation of a glucocorticoid-responsive reporter gene (Mouse MammaryTumorVirus) in response to rotenone indicated that it is highly unlikely that rotenone interacts directly with the glucocorticoid receptor. However, feeding male B6C3F1 mice a diet containing rotenone (600 ppm for 7 days) resulted in a 3-fold increase in serum levels of corticosterone relative to control animals. Corticosterone is the major glucocorticoid in rodents. CONCLUSION: Rotenone does not interact directly with the glucocorticoid receptor. Elevation of serum corticosterone levels in response to rotenone may explain the glucocorticoid-like effects of this compound, and may play a role in its anti-hepatocarcinogenic effect

The Topical Ocular Delivery of Rapamycin to Posterior Eye Tissues and the Suppression of Retinal Inflammatory Disease

Treatment of posterior eye diseases with intravitreal injections of drugs, while effective, is invasive and associated with side effects such as retinal detachment and endophthalmitis. In this work, we have formulated a model compound, rapamycin (RAP), in nanoparticle-based eye drops and evaluated the delivery of RAP to the posterior eye tissues in a healthy rabbit. We have also studied the formulation in experimental autoimmune uveitis (EAU) mouse model with retinal inflammation. Aqueous RAP eye drops were prepared using N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan (Molecular Envelope Technology - MET) containing 0.23 ± 0.001% w/v RAP with viscosity, osmolarity, and pH within the ocular comfort range, and the formulation (MET-RAP) was stable in terms of drug content at both refrigeration and room temperature for one month. The MET-RAP eye drops delivered RAP to the choroid-retina with a Cmax of 145 ± 49 ng/g (tmax = 1 hour). The topical application of the MET-RAP eye drops to the EAU mouse model resulted in significant disease suppression compared to controls, with activity similar to dexamethasone eye drops. The MET-RAP eye drops also resulted in a reduction of RORγt and an increase in both Foxp3 expression and IL-10 secretion, indicating a mechanism involving the inhibition of Th17 cells and the up-regulation of T-reg cells. The MET-RAP formulation delivers RAP to the posterior eye segments, and the formulation is active in EAU