Engineering tunability through electro-optic effects to manifest a multifunctional metadevice

Ultrafast modulation of the refractive index exhibits either linear or nonlinear electro-optic (EO) effect, which is extensively utilized in tunable photonic circuits. Silicon, a mature material for on-chip devices, lacks a strong electro-optic (EO) Pockels effect. Utilization of the Pockels effect alters the intrinsic property (refractive index) of the material that manifests tunability and offers expanded functionalities. Driven by the limited space constraints in data storage, sensing, and imaging applications, we propose an electrically tunable meta-device whose resonance wavelength and focal length can be tuned by varying applied electric fields in the visible range. The fundamental unit of a metalens is the barium titanate (BTO) diffractive optical element placed on indium titanium oxide (which serves as an electrode) with SiO₂ as the substrate. The metalens'' tunability is characterized by point spread function (PSF), full-width half-maximum (FWHM), and imaging bandwidth that demonstrates the tuning of resonance wavelength and focal length. Moreover, polarization-insensitive meta-holograms are realized at a wavelength of 633 nm without utilizing propagation and Pancharatnam–Berry (PB) phase. The proposed study can find exciting applications in machine vision, broadband microscopy, and spectroscopy.

Engineering tunability through electro-optic effects, which demonstrates a multifunctional metadevice by controlling resonance wavelength tuning and zoom focusing.     

Concentrations and Source Assessment of Some Atmospheric Trace Elements in Northwestern Region of Tehran, Iran

Outdoor concentrations of some elements such as iron, aluminum, magnesium, titanium, copper, zinc, lead, manganese, sulfur, chromium and arsenic in PM₁₀ and PM_2.5, was evaluated at four points in north-western part of Tehran in winter 2007. The total concentration of the elements in PM₁₀ and PM_2.5 at the north Karegar avenue found to be as high as 82.05 and 60.64 μg/m³, respectively, while at the Arjantin square it was measured to be 34.30 and 28.03 μg/m³. The emission sources of the trace elements were attributed to the adjoining local industries in the west parts of Tehran.     

Effect of Water Extract of Cardiospermum grandiflorum Swartz on the Gravid Female Rat Uterus

The effect of a water extract of Cardiospermum grandiflorum Swartz (Sapindaceae) was investigated on a gravid female rat uterus. This extract showed a strong elevation in contractile activity, inhibited by atropine, of the female (pregnant) Wistar rat uterus. It was found to be dose dependent.     

Lateral rectus resection versus medial rectus re-recession for residual esotropia: early results of a randomized clinical trial

PURPOSE: To compare lateral rectus muscle resection with medial rectus muscle re-recession for patients with residual esotropia. METHODS: This randomized controlled clinical trial included 25 patients (mean age, 18.8 +/- 8.7 years) with residual esotropia who were candidates for reoperation. They were randomly assigned into two groups: re-recession group (n = 12), in which the medial rectus muscle was recessed again, and the resection group (n = 13), in which lateral rectus muscle resection was performed. Postoperative deviation < or =10 prism dioptres was considered to be treatment success. RESULTS: The success rate of the re-recession group and the resection group was 67% and 54%, respectively; this difference was not statistically significant. Each 1 mm of medial rectus re-recession and lateral rectus resection corrected 7.5 +/- 1.2 and 2.5 +/- 0.5 prism dioptres of residual esotropia, respectively. In 50% of the re-recession group, mild medial rectus muscle underaction occurred; however, only 16.5% developed an increase in the near point of convergence. Major intraoperative and postoperative complications, including overcorrection and slippage or a lost muscle, did not occur in any of the patients. CONCLUSIONS: Medial rectus muscle re-recession can be a substitute for lateral rectus muscle resection in patients with residual esotropia. The resultant underaction of the medial rectus muscle after re-recession is relatively mild and causes no major problems.     

Findings of bilateral coronary to pulmonary artery fistula in 64-multislice computed tomographic angiography: correlation with catheter angiography

A 63-year-old man, who underwent conventional coronary angiography, because of a finding of a confusing vascular structure, was referred for 64-multislice spiral computed tomography (MSCT). His MSCT showed bilateral coronary-pulmonary artery fistula from both right and left coronary arteries via a dilated fistulous vascular malformation. Considering its reasonably high spatial and temporal resolutions, MSCT is regarded as a valuable technique to clarify the diagnosis in incidentally found equivocal cases of coronary fistula in conventional coronary angiography.     

c-myc and skp2 coordinate p27 degradation, vascular smooth muscle proliferation, and neointima formation induced by the parathyroid hormone-related protein

Parathyroid hormone-related protein (PTHrP) contains a classical bipartite nuclear localization signal. Nuclear PTHrP induces proliferation of arterial vascular smooth muscle cells (VSMC). In the arterial wall, PTHrP is markedly up-regulated in response to angioplasty and promotes arterial restenosis. PTHrP overexpression exacerbates arterial restenosis, and knockout of the PTHrP gene results in decreased VSMC proliferation in vivo. In arterial VSMC, expression of the cell cycle inhibitor, p27, rapidly decreases after angioplasty, and replacement of p27 markedly reduces neointima development. We have shown that PTHrP overexpression in VSMC leads to p27 down-regulation, mostly through increased proteosomal degradation. Here, we determined the molecular mechanisms through which PTHrP targets p27 for degradation. S-phase kinase-associated protein 2 (skp2) and c-myc, two critical regulators of p27 expression and stability, and neointima formation were up-regulated in PTHrP overexpression in VSMC. Normalization of skp2 or c-myc using small interfering RNA restores normal cell cycle and p27 expression in PTHrP overexpression in VSMC. These data indicate that skp2 and c-myc mediate p27 loss and proliferation induced by PTHrP. c-myc promoter activity was increased, and c-myc target genes involved in p27 stability were up-regulated in PTHrP overexpression in VSMC. In primary VSMC, PTHrP overexpression led to increased c-myc and decreased p27. Conversely, knockdown of PTHrP in primary VSMC from PTHrP(flox/flox) mice led to cell cycle arrest, p27 up-regulation, with c-myc and skp2 down-regulation. Collectively, these data describe for the first time the role of PTHrP in the regulation of skp2 and c-myc in VSMC. This novel PTHrP-c-myc-skp2 pathway is a potential target for therapeutic manipulation of the arterial response to injury.     

Comparison of Abbott IMx total homocysteine assay with a high pressure liquid chromatography method for the measurement of total homocysteine in plasma and serum from a Norwegian population.

In this study 189 samples were analysed for the measurement of homocysteine by the Abbott IMx homocysteine assay and an HPLC method. A strong correlation was obtained between the homocysteine measurements performed by the Abbott IMx homocysteine assay and the HPLC method (coefficient of correlation, r2 = 0.947, p < 0.0001). The plot of the difference for the homocysteine measurements between the two methods against the average of the two measurements resulted a mean difference of 0.80 +/- 6.66 (mean +/- 2SD), and 0.008 +/- 0.126 (mean +/- 2SD) for log converted values of homocysteine. The concentrations of homocysteine measured in all the samples by the two methods were not significantly different. However, the Abbott IMx homocysteine assay measured the concentrations of total homocysteine in hyperhomocysteinemia as significantly higher than the HPLC method (25.00 micromol/l vs. 23.12 micromol/l, p < 0.0001). More studies may be required to explore factors that may influence measurements of homocysteine by the Abbott IMx homocysteine assay and the HPLC method.     

Direct comparison of an intravascular and an extracellular contrast agent for quantification of myocardial perfusion

A direct comparison of extracellular and intravascular contrast agents for the assessment of myocardial perfusion was carried out in a porcine model (N = 5) with a flow-limiting occluder on the left anterior descending coronary artery. Rapid imaging during the first pass of an extracellular or intravascular contrast agent with a saturation-recovery-prepared TurboFLASH sequence showed comparable peak contrast-to-noise enhancements in myocardial tissue regions with flows averaging 1.1 ± 0.2 at baseline to 4.8 ± 0.6 ml/min/g during hyperemia. The coefficient of variation between the MR estimates of blood flow with Gadomer-17 and the microsphere blood flow measurements was 11 ± 11, while the corresponding coefficient of variation for blood flow estimates with the extracellular CA was 23 ± 11. Blood volume differences between rest and hyperemia observed with the intravascular tracer were significant (V _vasc(rest) = 0.078 ± 0.013 ml/g, versus V _vasc(hyperemia) = 0.102 ± 0.019 ml/g; p < 0.05). The effects of water exchange were minimized through the choice of pulse sequence parameters to provide blood volume estimates consistent with the changes expected between rest and hyperemia. This study represents the first application of multiple indicators in first pass imaging studies for the assessment of myocardial perfusion. The use of an intravascular instead of an extracellular contrast agent allows a reduction of the degrees of freedom for modeling tissue residue curves and results in improved accuracy of blood flow estimates.     

Evaluation of a pharmacist vs. Haematologist-managed anticoagulation clinic: A retrospective cohort study

IntroductionWarfarin is the core component in the management of various thromboembolic disorders, which requires specialized expertise to optimize outcomes. There is limited data comparing a pharmacist vs. a haematologist-managed anticoagulation clinic in our setting, and in the Middle East. We aimed to evaluate the effectiveness and safety of a pharmacist vs. a haematologist-managed anticoagulation clinic in the Ambulatory Care Center at King Abdulaziz Medical City, Jeddah, Saudi Arabia.MethodsA retrospective cohort study was conducted from 2016 to 2018, which included adult patients who have been followed-up for at least six months and who received warfarin for an extended period. The primary outcome was the proportion of time the patients in the two arms were in the therapeutic range. The secondary outcomes were the differences in expanded time in the therapeutic range, as well as the frequency of bleeding and thromboembolic events between the two arms.ResultsWe enrolled 104 and 124 patients in the pharmacist and haematologist arms respectively. The median time in the therapeutic range for the pharmacist arm was 71.4%, IQR (60.8–83.8) vs. 65%, IQR (43.5–79.1), in the haematologist arm (p = 0.0049). The median expanded time in the therapeutic range was 86.4%, IQR (77.5–95.3) vs. 81.21%, IQR (67.1–93.3) in the pharmacist vs. haematologist arm (p = 0.015) respectively. Major bleeding events occurred in 5.7 % vs. 3.2 %, and thromboembolic events in 5.7% vs. 4%, in the pharmacist vs. haematologist arm respectively.ConclusionsOur results demonstrated that the time in the therapeutic range was significantly higher in the pharmacist arm, with no significant difference in bleeding and thromboembolic events compared to the haematologist arm.