98 research outputs found

    The results of photorefractive keratectomy with Mitomycin-C in myopia correction after five years

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    Objective: To evaluate the results of photorefractive keratectomy (PRK) with mitomycin C in myopia correction after five years. Methods: This is a cross sectional study which included 145 eyes of 74 patients in 18 to 51 years age group that were undergoing Photorefractive keratectomy with mitomycin C using Allegretto Wave Eye-Q 400-Hz excimer laser platform in Markazi Eye Center, Tehran, Iran. All the surgical procedures were performed by the same surgeon. After five years follow-up evaluation including BCVA, UCVA, Refractive error measurement and external eye examination was performed. Results: The mean diopter of spherical equivalent before surgery was -3.40±1.73. The following findings were obtained after 5 years follow up visit: The mean spherical equivalent value: -0.08±0.40, the mean Log MARUCVA: 0.02±0.07, the mean Log MAR BCVA: 0.00±0.04. Conclusion: PRK is an effective, safe and predictable method used to correct myopia. The wave frontoptimized algorithm of the Allegretto Wave Eye-Q 400-Hz excimer laser platform demonstrated good refractive and visual results. Presence of variables such as gender, age and astigmatism before operation have no significant impact on the result of this operation. © 2016, Professional Medical Publications. All rights reserved

    Targeting delivery of lipocalin 2-engineered mesenchymal stem cells to colon cancer in order to inhibit liver metastasis in nude mice

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    One of the major obstacles in cancer therapy is the lack of anticancer agent specificity to tumor tissues. The strategy of cell-based therapy is a promising therapeutic option for cancer treatment. The specific tumor-oriented migration of mesenchymal stem cells (MSCs) makes them a useful vehicle to deliver anticancer agents. In this study, we genetically manipulated bone marrow-derived mesenchymal stem cells with their lipocalin 2 (Lcn2) in order to inhibit liver metastasis of colon cancer in nude mice. Lcn2 was successfully overexpressed in transfected MSCs. The PCR results of SRY gene confirmed the presence of MSCs in cancer liver tissue. This study showed that Lcn2-engineered MSCs (MSC-Lcn2) not only inhibited liver metastasis of colon cancer but also downregulated the expression of vascular endothelial growth factor (VEGF) in the liver. Overall, MSCs by innate tropism toward cancer cells can deliver the therapeutic agent, Lcn2, and inhibit cancer metastasis. Hence, it could be a new modality for efficient targeted delivery of anticancer agent to liver metastasis. © 2015, International Society of Oncology and BioMarkers (ISOBM)

    Effects of cadmium on spermatogonia, spermatocytes and sperm motility of Caspian kutum, Rutilus frisii kutum

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    Cadmium is one the common heavy metals that usually enters the Caspian Sea and the riverine ecosystems. Effect of Cadmium on spermatogenesis in Caspian kutum and motility of spermatozoa were studied. At first, kutum testis was exposed to Cadmium using in vitro testis culture in 10-5, 10-6 and 10-7 M concentration of CdCl2 solution for 3 and 6 days and in the second experiment, spermatozoa motility was evaluated after exposure to 0, 0.01, 0.1, 1, 10, 100 and 1000 mg/l of CdCl2 solutions. With the increase in Cadmium concentration, due to the reclining effect of Cadmium on spermatogenesis, the number of spermatocytes and size of germ cells decreased significantly. Motility of spermatozoa decreased significantly with increasing Cadmium concentration and its motility stopped in 1000 mg/l. Reduction in quality and quantity of germ cells could impair offspring production and recline their viability and thus posing threats on valuable kutums stocks

    Determination of some seminal plasma indices, sperm density and sperm motility in the Persian sturgeon Acipenser persicus

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    Some biological aspects of semen were investigated in the Persian sturgeon, Acipenser persicus, by determination of seminal plasma indices (ionic composition and osmolality), sperm density and their relationships with sperm motility. The osmolality of seminal plasma ranged from 42.00 to 111.00 mOsmol Kg-1. The concentrations of Sodium (Na+), Potassium (K+), Chloride (Cl-), Calcium (Ca2+) and Magnesium (Mg2+) ions were 62.44±6.82, 6.92±0.88, 21.11±5.41, 0.79± 0.03 and 0.52±0.03mM L-1, respectively. The sperm density was 8.34±1.38×109 spz/ml. The Sodium/Potassium and Calcium/Potassium ratios were 9.02 and 0.13, respectively. The following significant positive correlations were found between seminal plasma indices; osmolality - Cl- (r2= 0.492, P0.05). No relationship was observed between sperm density and its motility at the concentrations tested (r2= 0.015, P>0.05). The ionic composition and osmolality of seminal plasma reveals an inter-species specific as well high secretory activity of sperm duct. The clear differences observed in A. persicus should be considered when cryopreservation methods for sperm are developed in Acipenseridae species

    SPIDER: Probing the Early Universe with a Suborbital Polarimeter

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    We evaluate the ability of SPIDER, a balloon-borne polarimeter, to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological signal with r=0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the SPIDER field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all SPIDER frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the "Southern Hole." We show that two ~20-day flights of the SPIDER instrument can constrain the amplitude of the B-mode signal to r<0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight.Comment: 29 pages, 8 figures, 4 tables; v2: matches published version, flight schedule updated, two typos fixed in Table 2, references and minor clarifications added, results unchange

    Factors Associated with Anxiety in Premature Coronary Artery Disease Patients : THC-PAC Study

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    Anxiety may negatively affect the course of coronary artery disease (CAD). The aim of this study was to assess which factors are associated with anxiety in young adults with CAD. A cohort of individuals with premature coronary artery disease was formed between 2004-2011, as the Tehran Heart Center's Premature Coronary Atherosclerosis Cohort (THC-PAC) study. Patients (men 6445-year-old, and women 6455-year-old) were visited between March 2013 and February 2014. All participants were examined, and their demographic, clinical, and laboratory data were collected. Then, all participants filled in the Beck Anxiety Inventory. Logistic regression models were used to identifying factors related to anxiety in both sexes. During the study, 708 patients (mean [SD] age: 45.3 [5.8] y, men:48.2%) were visited. Anxiety was present in 53.0% of participants (66.0% of women and 39.0% of men). The logistic regressions model showed that the associated factors for anxiety in men were opium usage (OR=1.89, 95% CI: 1.09-3.27), positive family history (OR=1.49, 95% CI:0.94-2.35), and creatinine serum level (OR=1.17, 95% CI:1.05-1.303); and in women were major adverse cardiac events (MACE) during follow-up (OR=2.30, 95% CI:1.25-4.23), hypertension (OR=1.71, 95% CI:1.07-2.73) and the duration of CAD (OR=0.99, 95% CI:0.98-1.00). In premature CAD patients, the determinants of anxiety seem to be different in each sex. Opium usage, positive family history of CAD, and creatinine serum levels in men, and MACE, hypertension, and duration of CAD in women appear the relevant factors in this regard

    2022 Upgrade and Improved Low Frequency Camera Sensitivity for CMB Observation at the South Pole

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    Constraining the Galactic foregrounds with multi-frequency Cosmic Microwave Background (CMB) observations is an essential step towards ultimately reaching the sensitivity to measure primordial gravitational waves (PGWs), the sign of inflation after the Big-Bang that would be imprinted on the CMB. The BICEP Array telescope is a set of multi-frequency cameras designed to constrain the energy scale of inflation through CMB B-mode searches while also controlling the polarized galactic foregrounds. The lowest frequency BICEP Array receiver (BA1) has been observing from the South Pole since 2020 and provides 30 GHz and 40 GHz data to characterize the Galactic synchrotron in our CMB maps. In this paper, we present the design of the BA1 detectors and the full optical characterization of the camera including the on-sky performance at the South Pole. The paper also introduces the design challenges during the first observing season including the effect of out-of-band photons on detectors performance. It also describes the tests done to diagnose that effect and the new upgrade to minimize these photons, as well as installing more dichroic detectors during the 2022 deployment season to improve the BA1 sensitivity. We finally report background noise measurements of the detectors with the goal of having photon noise dominated detectors in both optical channels. BA1 achieves an improvement in mapping speed compared to the previous deployment season.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 2022 (AS22
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