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Dadmehr M, Shahi SC, Malekkiani M, Korouzhdehi B, Tavassoli A. A stem-loop like aptasensor for sensitive detection of aflatoxin based on graphene oxide/AuNPs nanocomposite platform. Food Chem 2023; 402:134212. [DOI: 10.1016/j.foodchem.2022.134212] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 08/27/2022] [Accepted: 09/09/2022] [Indexed: 01/10/2023]
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2
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Esmaeilian Y, Amiri MB, Tavassoli A, Caballero-Calvo A, Rodrigo-Comino J. Replacing chemical fertilizers with organic and biological ones in transition to organic farming systems in saffron (Crocus sativus) cultivation. Chemosphere 2022; 307:135537. [PMID: 35850217 DOI: 10.1016/j.chemosphere.2022.135537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
To evaluate the response of saffron to animal manure, and biological and chemical fertilizer in an arid climate, an experiment was performed as split plots based on a randomized complete blocks design with three replications during three consecutive crop growth seasons (2015-2018) at the Research Farm of University of Gonabad, Iran. The experimental treatments included application (60 t ha-1) and non-application (control) of manure as the main plot and the use of biosulfur (5 kg ha-1), biophosphate (3 L ha-1), nitroxin (3 L ha-1), chemical fertilizer (150, 100, and 100 kg ha-1 of urea, triple superphosphate, and potassium sulfate, respectively), and no fertilizer application (control) as the sub-plot. The results showed a highly significant response of the quantitative traits of saffron to the application of manure, which increased the leaf, flower, and corm indices of saffron by a mean of 15.1-35.7% than control. The interaction effect of manure with biological and chemical fertilizers for leaf, flower, and weeds indices of saffron was significant. There was no significant difference between the interaction treatments of manure and chemical fertilizer with nitroxin and biophosphorus fertilizers in most of the mentioned traits in the three experiment years. The simultaneous application of these fertilizers increased the average by about 60, 105, 135, 110, 165, and 55% of the leaf dry weight, the number of flowers, fresh flower yield, dry flower yield, dry stigma yield, and weed dry weight of saffron, respectively as compared to control. There was no significant difference between the chemical fertilizer with nitroxin or biophosphate in terms of the effect on the traits related to saffron corm so the use of these fertilizers, as compared to control, increased replacement corm weight, replacement corm size, and bud number per corm by, respectively, about 35, 60, and 40% on average. The chemical and biological fertilizers improved the content of crocin, picrocrocin, and safranal of saffron stigma. The best results were obtained from the use of chemical fertilizers, although no significant difference was observed between this treatment and the nitroxin and biophosphate treatments. Overall, the results of this three-year experiment show a very high response of the saffron plant to the simultaneous use of manure and biological fertilizers and, therefore, it is possible to replace chemical fertilizers with organic and biological fertilizers in saffron cultivation to implement organic agriculture and achieve acceptable quantitative and qualitative yields in areas similar to the experiment location.
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Affiliation(s)
| | | | | | - Andrés Caballero-Calvo
- Department of Regional Geographic Analysis and Physical Geography, Faculty of Philosophy and Letters, Campus Universitario de Cartuja, University of Granada, 18071, Granada, Spain.
| | - Jesús Rodrigo-Comino
- Department of Regional Geographic Analysis and Physical Geography, Faculty of Philosophy and Letters, Campus Universitario de Cartuja, University of Granada, 18071, Granada, Spain.
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3
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Dadmehr M, Korouzhdehi B, Tavassoli A, Malekkiani M. Photocatalytic activity of green synthesized cadmium sulfide quantum dots on the removal of RhB dye and its cytotoxicity and antibacterial studies. Nanotechnology 2022; 33:395101. [PMID: 35714520 DOI: 10.1088/1361-6528/ac79bc] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Presence of inorganic pollutants in water reservoirs is the treating factor for human health and environment. Semiconductor quantum dots (QDs) has been regarded as one of the most efficient nanoparticles for their enhanced photocatalytic activity. Medicinal plants are the safe sources to provide green template for biosynthesis of inorganic nanoparticles such as quantum dots. In order to determine the photocatalytic and biological application of cadmium sulfide quantum dots (CdS QDs), a biosynthesis approach was employed using saffron (Crocus sativus L.) stigma extract as the green reaction substrate. The biosynthesis process was evaluated at different pH condition to obtain the most efficient CdS QDs. Characterization of prepared CdS QDs were determined through UV-vis and fluorescence spectroscopy, FTIR and TEM analysis. The obtained results showed well dsispersed and uniform QDs during green synthesis at the optimum condition. The absorption and electrical properties of green synthesized CdS QDs showed the lowest energy bandgap of 2.4 at pH 11. Photocatalytic activity of CdS QDs on Rhodamine B degradation showed 92% degradation after 80 min under UV light irradiation. The antibacterial and cell cytotoxicity of green synthesized CdS QDs were assayed by disk diffusion and MTT assays respectively. Obtained results showed significant antibacterial effect of CdS QDs against gram-positive and gram-negative bacteria includingB. subtilis(90%) andE. coli(96%) respectively. Moreover, cytotoxicity of prepared CdS Qds through MTT assay indicated 79% apoptosis induction on MCF-7 breast cancer cells.
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Affiliation(s)
- Mehdi Dadmehr
- Department of Biology, Payame Noor University, Tehran, Iran
| | - Behnaz Korouzhdehi
- Department of Biotechnology, College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
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Cheraghi Shahi S, Dadmehr M, Korouzhdehi B, Tavassoli A. A novel colorimetric biosensor for sensitive detection of aflatoxin mediated by bacterial enzymatic reaction in saffron samples. Nanotechnology 2021; 32:505503. [PMID: 34488207 DOI: 10.1088/1361-6528/ac23f7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 09/06/2021] [Indexed: 05/28/2023]
Abstract
Aflatoxin is regarded as the potent carcinogenic agent which is secreted from fungi and present in some food products. So far, many detection methods have been developed to determine the trace amounts of aflatoxin in foods. In the present study a colorimetric competitive assay for detection of aflatoxin B1 (AFB1) has been developed based on interaction of gelatin functionalized gold nanoparticles (AuNPs@gelatin) in specific enzymatic reaction. Bacterial supernatant containing gelatinase enzyme were used as the substrate that could digest the coated gelatin on the surface of AuNPs and following in the presence of NaCl medium ingredient resulted to color change of AuNPs colloidal solution from red to purple. It was observed that with addition of aflatoxin to the bacterial supernatant, aflatoxin could interfere in aggregation of AuNPs and inhibited the process which subsequently prevent the expected color change induced by AuNPs aggregation. The supernatant containing AuNPs were investigated to analyze their induced surface plasmon resonance spectra through UV-visible spectroscopy. The absorption values were directly proportional with the applied AFB1 concentration. The experiment conditions including incubation time, AuNPs concentration and pH were investigated. The obtained results showed that through this approach we could detect the AFB1 in a linear range from 10 to 140 pg ml-1, with detection limit of 4 pg ml-1. Real sample assay in saffron samples showed recoveries percentage of 92.4%-95.3%. The applied approach proposed simple, cost effective and specific method for detection of AFB1 toxin in food samples.
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Affiliation(s)
| | - Mehdi Dadmehr
- Department of Biology, Payame Noor University, Tehran, Iran
| | - Behnaz Korouzhdehi
- Department of Biotechnology, College of Agriculture & Natural Resources, University of Tehran, Karaj, Iran
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Asby DJ, Radigois MG, Wilson DC, Cuda F, Chai CLL, Chen A, Bienemann AS, Light ME, Harrowven DC, Tavassoli A. Triggering apoptosis in cancer cells with an analogue of cribrostatin 6 that elevates intracellular ROS. Org Biomol Chem 2018; 14:9322-9330. [PMID: 27722456 DOI: 10.1039/c6ob01591c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Elevation of reactive oxygen species (ROS) is both a consequence and driver of the upregulated metabolism and proliferation of transformed cells. The resulting increase in oxidative stress is postulated to saturate the cellular antioxidant machinery, leaving cancer cells susceptible to agents that further elevate their intracellular oxidative stress. Several small molecules, including the marine natural product cribrostatin 6, have been demonstrated to trigger apoptosis in cancer cells by increasing intracellular ROS. Here, we report the modular synthesis of a series of cribrostatin 6 derivatives, and assessment of their activity in a number of cell lines. We establish that placing a phenyl ring on carbon 8 of cribrostatin 6 leads to increased potency, and observe a window of selectivity towards cancer cells. The mechanism of activity of this more potent analogue is assessed and demonstrated to induce apoptosis in cancer cells by increasing ROS. Our results demonstrate the potential for targeting tumors with molecules that enhance intracellular oxidative stress.
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Affiliation(s)
- D J Asby
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
| | - M G Radigois
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK. and Institute of Chemical and Engineering Sciences, A*Star, 138665, Singapore
| | - D C Wilson
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
| | - F Cuda
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
| | - C L L Chai
- Institute of Chemical and Engineering Sciences, A*Star, 138665, Singapore and Department of Pharmacy, National University of Singapore, 117543, Singapore
| | - A Chen
- Institute of Chemical and Engineering Sciences, A*Star, 138665, Singapore
| | - A S Bienemann
- School of Clinical Sciences, University of Bristol, Southmead Hospital, Bristol, BS10 5NB, UK
| | - M E Light
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
| | - D C Harrowven
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
| | - A Tavassoli
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK. and The Institute for Life Sciences, University of Southampton, Southampton, UK
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Tavassoli A, Grytsiv A, Rogl G, Romaka VV, Michor H, Reissner M, Bauer E, Zehetbauer M, Rogl P. The half Heusler system Ti1+xFe1.33−xSb–TiCoSb with Sb/Sn substitution: phase relations, crystal structures and thermoelectric properties. Dalton Trans 2018; 47:879-897. [DOI: 10.1039/c7dt03787b] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Phase equilibria for Heusler Phase Ti1+xFe1.33−xSb at 800 °C and calculated isosurfaces (ϒ = 0.42) of the electron localization function in TiFe1.25Sb.
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Affiliation(s)
- A. Tavassoli
- Institute of Materials Chemistry and Research
- University of Vienna
- A-1090 Wien
- Austria
- Physics of Nanostructured Materials
| | - A. Grytsiv
- Institute of Materials Chemistry and Research
- University of Vienna
- A-1090 Wien
- Austria
- Institute of Solid State Physics
| | - G. Rogl
- Institute of Materials Chemistry and Research
- University of Vienna
- A-1090 Wien
- Austria
- Institute of Solid State Physics
| | - V. V. Romaka
- Department of Materials Science and Engineering
- Lviv Polytechnic National University
- 79013 Lviv
- Ukraine
| | - H. Michor
- Institute of Solid State Physics
- TU Wien
- A-1040 Wien
- Austria
| | - M. Reissner
- Institute of Solid State Physics
- TU Wien
- A-1040 Wien
- Austria
| | - E. Bauer
- Institute of Solid State Physics
- TU Wien
- A-1040 Wien
- Austria
- Christian Doppler Laboratory for Thermoelectricity
| | - M. Zehetbauer
- Physics of Nanostructured Materials
- Faculty of Physics
- University of Vienna
- A-1090 Wien
- Austria
| | - P. Rogl
- Institute of Materials Chemistry and Research
- University of Vienna
- A-1090 Wien
- Austria
- Christian Doppler Laboratory for Thermoelectricity
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Vahidnezhad H, Youssefian L, Baghdadi T, Sotoudeh S, Tavassoli A, Zeinali S, Afsharaalam S, Uitto J. Phenotypic heterogeneity in PIK3CA-related overgrowth spectrum. Br J Dermatol 2016; 175:810-4. [PMID: 27037860 DOI: 10.1111/bjd.14618] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- H Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, U.S.A.,Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.,Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - L Youssefian
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, U.S.A.,Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - T Baghdadi
- Department of Orthopedic Surgery, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - S Sotoudeh
- Department of Dermatology, Children's Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - A Tavassoli
- Aliasghar Pediatric Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - S Zeinali
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - S Afsharaalam
- Department of Biology, Islamic Azad University, Tehran, Iran
| | - J Uitto
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, U.S.A..
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Jones DC, Mistry IN, Tavassoli A. Post-translational control of protein function with light using a LOV-intein fusion protein. Mol Biosyst 2016; 12:1388-93. [PMID: 26940144 DOI: 10.1039/c6mb00007j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Methods for the post-translational control of protein function with light hold much value as tools in cell biology. To this end, we report a fusion protein that consists of DnaE split-inteins, flanking the light sensitive LOV2 domain of Avena sativa. The resulting chimera combines the activities of these two unrelated proteins to enable controlled formation of a functional protein via upregulation of intein splicing with blue light in bacterial and human cells.
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Affiliation(s)
- D C Jones
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
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9
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Mistry IN, Smith PJS, Wilson DI, Tavassoli A. Probing the epigenetic regulation of HIF-1α transcription in developing tissue. Mol BioSyst 2015; 11:2780-5. [DOI: 10.1039/c5mb00281h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
HIF-1-mediated hypoxia signalling in embryonic tissue is probed by assessing the methylation status of the HIF-1α and EPO HRE promoters using bisulfite sequencing.
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Affiliation(s)
| | - P. J. S. Smith
- Institute for Life Sciences
- University of Southampton
- Southampton
- UK
| | - D. I. Wilson
- Human Development and Health
- Faculty of Medicine
- University of Southampton
- Southampton
- UK
| | - A. Tavassoli
- Chemistry
- University of Southampton
- Southampton
- UK
- Institute for Life Sciences
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Asby DJ, Cuda F, Hoakwie F, Miranda E, Tavassoli A. HIF-1 promotes the expression of its α-subunit via an epigenetically regulated transactivation loop. ACTA ACUST UNITED AC 2014; 10:2505-8. [DOI: 10.1039/c4mb00351a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A HIF-1 protein–protein interaction inhibitor is used to establish the presence of a HIF-1α transactivation loop in hypoxia.
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Affiliation(s)
- D. J. Asby
- Chemistry
- University of Southampton
- Southampton, UK
| | - F. Cuda
- Chemistry
- University of Southampton
- Southampton, UK
| | - F. Hoakwie
- Chemistry
- University of Southampton
- Southampton, UK
| | - E. Miranda
- Chemistry
- University of Southampton
- Southampton, UK
| | - A. Tavassoli
- Chemistry
- University of Southampton
- Southampton, UK
- Cancer Sciences
- Faculty of Medicine
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Frey J, Tavassoli A, Ringach D. Relative contributions of stimulus motion and VOR to eye movement during gaze pursuit. J Vis 2012. [DOI: 10.1167/12.9.993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Tavassoli A, Noorshafiee S, Nazarzadeh R. Comparison of excision with primary repair versus Limberg flap. Int J Surg 2011; 9:343-6. [DOI: 10.1016/j.ijsu.2011.02.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 02/15/2011] [Accepted: 02/16/2011] [Indexed: 11/25/2022]
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van der Linde I, Tavassoli A, Bovik AC, Cormack LK. Classification images reveal observer templates underlying the direct tilt illusion. J Vis 2010. [DOI: 10.1167/6.6.451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Tavassoli A, van der Linde I, Bovik AC, Cormack LK. Noise unveils spatial frequency and orientation selectivity during visual search. J Vis 2010. [DOI: 10.1167/6.6.450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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15
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Tavassoli A, van der Linde I, Bovik A, Cormack L. Selectivity for multiple orientations in visual search. J Vis 2010. [DOI: 10.1167/8.6.1078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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16
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Tavassoli A, Palmer CR, Cormack LK. Frequency and space domain classification images for motion detection. J Vis 2010. [DOI: 10.1167/3.9.397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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17
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Bagheri R, Tavassoli A, Sadrizadeh A, Mashhadi MR, Shahri F, Shojaeian R. The role of thoracoscopy for the diagnosis of hidden diaphragmatic injuries in penetrating thoracoabdominal trauma. Interact Cardiovasc Thorac Surg 2009; 9:195-7; discussion 197-8. [DOI: 10.1510/icvts.2008.195685] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Tavassoli A, Linde IVD, Bovik AC, Cormack LK. Eye movements selective for spatial frequency and orientation during active visual search. Vision Res 2008; 49:173-81. [PMID: 18992270 DOI: 10.1016/j.visres.2008.10.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 09/21/2008] [Accepted: 10/01/2008] [Indexed: 11/16/2022]
Abstract
Visual search can simply be defined as the task of looking for objects of interest in cluttered visual environments. Typically, the human visual system succeeds at this by making a series of rapid eye movements called saccades, interleaved by discrete fixations. However, very little is known on how the brain programs saccades and selects fixation loci in such naturalistic tasks. In the current study, we use a technique developed in our laboratory based on reverse-correlation(1) and stimuli that emulate the natural visual environment to examine observers' strategies when seeking low-contrast targets of various spatial frequency and orientation characteristics. We present four major findings. First, we provide strong evidence of visual guidance in saccadic targeting characterized by saccadic selectivity for spatial frequencies and orientations close to that of the search target. Second, we show that observers exhibit inaccuracies and biases in their estimates of target features. Third, a complementarity effect is generally observed: the absence of certain frequency components in distracters affects whether they are fixated or mistakenly selected as the target. Finally, an unusual phenomenon is observed whereby distracters containing close-to-vertical structures are fixated in searches for nonvertically oriented targets. Our results provide evidence for the involvement of band-pass mechanisms along feature dimensions (spatial frequency and orientation) during visual search.
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Affiliation(s)
- A Tavassoli
- Center for Perceptual Systems, The University of Texas at Austin, TX 78712, USA.
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Haghighi B, Tavassoli A. Flow-injection analysis of nitrate by reduction to nitrite and gas-phase molecular absorption spectrometry. Fresenius J Anal Chem 2001; 371:1113-8. [PMID: 11798108 DOI: 10.1007/s002160101070] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two flow-injection manifolds have been investigated for the determination of nitrate. These manifolds are based on the reduction of nitrate to nitrite and determination of nitrite by gas-phase molecular absorption spectrophotometry. Nitrate sample solution (300 microL) which is injected to the flow line, is reduced to nitrite by reaction with hydrazine or passage through the on-line copperized cadmium (Cd-Cu) reduction column. The nitrite produced reacts with a stream of hydrochloric acid and the evolved gases are purged into the stream of O2 carrier gas. The gaseous phase is separated from the liquid phase using a gas-liquid separator and then swept into a flow-through cell which has been positioned in the cell compartment of an UV-visible spectrophotometer. The absorbance of the gaseous phase is measured at 204.7 nm. A linear relationship was obtained between the intensity of absorption signals and concentration of nitrate when Cd-Cu reduction method was used, but a logarithmic relationship was obtained when the hydrazine reduction method was used. By use of the Cd-Cu reduction method, up to 330 microg of nitrate was determined. The limit of detection was 2.97 microg nitrate and the relative standard deviations for the determination of 12.0, 30.0 and 150 microg nitrate were 3.32, 3.87 and 3.6%, respectively. Maximum sampling rate was approximately 30 samples per hour. The Cd-Cu reduction method was applied to the determination of nitrate and the simultaneous determination of nitrate and nitrite in meat products, vegetables, urine, and a water sample.
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Affiliation(s)
- B Haghighi
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan, Iran.
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Pixley JS, Tavassoli M, Zanjani ED, Shaft DM, Futamachi KJ, Sauter T, Tavassoli A, MacKintosh FR. Transplantation in utero of fetal human hematopoietic stem cells into mice results in hematopoietic chimerism. Pathobiology 1994; 62:238-44. [PMID: 7541206 DOI: 10.1159/000163916] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Allogeneic and xenogeneic hematolymphoid chimerism has been achieved in large and small animals using varied techniques to circumvent immune mediated graft rejection by the recipient. We show here the establishment of long-term chimerism in normal mice transplanted in utero with human fetal hematopoietic stem cells (HSC). HSCs from fetal (13-20 weeks' gestation) human livers were injected into fetal mouse peritoneal cavities on days 11-13 of gestation. Histologic examination demonstrated human chimerism in 29% of 38 live born mice using fluorescein conjugated antibodies to both the CD45 and CD14 antigens present on human peripheral blood (PB) cells. Further investigation using flow cytometric analysis of cells from 70 mice transplanted in utero revealed 28% of mice greater than 16 weeks of age contained human cells in at least one organ at the following frequencies: 14% PB, 8% bone marrow, 8% spleen and 12% thymus. These data indicate that human fetal HSC can be engrafted into mouse fetuses. Additionally, the identification of circulating human cells 18 months following transplantation supports the engraftment and proliferation of a primitive hematopoietic progenitor.
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Affiliation(s)
- J S Pixley
- Ioannis A. Lougaris VA Medical Center, Reno, NV 89520, USA
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