24 research outputs found
Assessing the contamination level, sources and risk of potentially toxic elements in urban soil and dust of Iranian cities using secondary data of published literature
Research in urban geochemistry has been expanding globally in recent years, following the trend of the ever-increasing human population living in cities. Environmental problems caused by non-degradable pollutants such as metals and metalloids are of particular interest considering the potential to affect the health of current and future urban residents. In comparison with the extensive global research on urban geochemistry, Iranian cities have not received sufficient study. However, rapid and often uncontrolled urban expansion in Iran over recent years has contributed to an increasing number of studies concerning contamination of urban soil and dust. The present work is based on a comprehensive nationwide evaluation and intercomparison of published quantitative datasets to determine the contamination levels of Iranian cities with respect to potentially toxic elements (PTEs) and assess health risks for urban population. Calculation of geoaccumulation, pollution, and integrated pollution indices facilitated the identification of the elements of most concern in the cities, while both carcinogenic and non-carcinogenic risks have been assessed using a widely accepted health-risk model. The analysis of secondary, literature data revealed a trend of contamination, particularly in old and industrial cities with some alarming levels of health risks. Among the elements of concern, As, Cd, Cu, and Pb were found to be most enriched in soils and dusts of the studied cities based on the calculated geochemical indices. The necessity of designing strategic plans to mitigate possible adverse effects of elevated PTE concentrations in urban environments is emphasized considering the role of long-term exposure in the occurrence of chronic carcinogenic and non-carcinogenic health problems. © 2021, The Author(s), under exclusive licence to Springer Nature B.V
Genesis of the Eastern Iranian bentonite deposits
Numerous bentonite deposits are located in Southern Khorasan (Eastern Iran), especially in Ferdows and Sarayan counties. We studied the genesis of these bentonites at seven deposits (Chah-Taleb, Chah-Keshmir, Chah-Golestan, Chah-Pirouz, Gholeh-Gelia, Kharman-Sar and Khal-Kooh) using petrological, mineralogical and geochemical data (including X-ray diffraction and fluorescence, and inductively coupled plasma-mass spectrometry) from both bentonites and parent rock samples. The deposits mainly consist of Na-montmorillonite and opaline silica, with lesser amounts of quartz, feldspars, carbonates, halite, zeolites, and illite. The studied deposits formed in a volcanic arc setting and their magma series are calc-alkaline, except for the Kharman-Sar deposit, which is tholeiitic in composition. The presence of significant amounts of opaline silica indicates a low fluid flow rate in these systems, in spite of the high leaching of alkalis. The strata-bound nature of the studied deposits, as well as the high amount of montmorillonite, the presence of gypsum layers alternating with those of bentonite and the lack of hydrothermal alteration suggest that these Iranian bentonite deposits were formed through diagenetic processes in lagoon environments, by means of the alteration of intermediate to acidic precursors, trachy-andesite to rhyolite, belonging to two volcanic provinces: one pyroclastic realm in Ferdows, and another volcaniclastic in Sarayan.This research was partly funded by the Iran National Science Foundation (contract no. 90004849 ), Spanish Group CTS-946 (Junta de Andalucia) and MINECO project CGL2016-80833-R . We also acknowledge the School of Geology of the University of Tehran for sample preparation and some geochemical tests
Safety, effectiveness, and cost-effectiveness of Argus II in patients with retinitis pigmentosa: A systematic review
AIM: To assess the effectiveness, safety, and cost-effectiveness of the Argus II in treatment of the retinitis pigmentosa (RP) patients. METHODS: The ProQuest, Web of Science, EMBASE, MEDLINE (via PubMed) were searched using combinations of the keywords of Argus, safety, effectiveness, bionic eye, retinal prosthesis, and RP through March 2018. The retrieved records were screened and then assessed for eligibility. RESULTS: Totally 926 records were retrieved from the searched databases and finally 12 studies included. The RP patients showed improvements in visual function after receiving the prosthesis, compared to the time before the prosthesis or the time it was off. This was measured by square localization, direction of motion, and grating visual acuity tests. No major adverse effect was reported for the Argus II prosthesis itself and/or the surgery to implement it, but the most frequently reported items were hypotony, and conjunctival dehiscence. The incremental cost-effectiveness ratio (ICER) was calculated to be �14603 per quality-adjusted life year (QALY) in UK and 207 616 per QALY in Canada. CONCLUSION: The available evidence shows that the Argus II prosthesis in RP patients is effective in improvement of their visual function. Some minor adverse effects are reported for the prosthesis. The cost-effectiveness studies show that the technology is cost-effective only at high levels of willingness-to-pay. © 2021 International Journal of Ophthalmology (c/o Editorial Office). All rights reserved
Genesis of the Eastern Iranian bentonite deposits
Numerous bentonite deposits are located in Southern Khorasan (Eastern Iran), especially in Ferdows and Sarayan
counties. We studied the genesis of these bentonites at seven deposits (Chah-Taleb, Chah-Keshmir, Chah-
Golestan, Chah-Pirouz, Gholeh-Gelia, Kharman-Sar and Khal-Kooh) using petrological, mineralogical and geochemical
data (including X-ray diffraction and fluorescence, and inductively coupled plasma-mass spectrometry)
from both bentonites and parent rock samples. The deposits mainly consist of Na-montmorillonite and opaline
silica, with lesser amounts of quartz, feldspars, carbonates, halite, zeolites, and illite. The studied deposits
formed in a volcanic arc setting and their magma series are calc-alkaline, except for the Kharman-Sar deposit,
which is tholeiitic in composition. The presence of significant amounts of opaline silica indicates a low fluid flow
rate in these systems, in spite of the high leaching of alkalis.
The strata-bound nature of the studied deposits, as well as the high amount of montmorillonite, the presence
of gypsum layers alternating with those of bentonite and the lack of hydrothermal alteration suggest that these
Iranian bentonite deposits were formed through diagenetic processes in lagoon environments, by means of the
alteration of intermediate to acidic precursors, trachy-andesite to rhyolite, belonging to two volcanic provinces:
one pyroclastic realm in Ferdows, and another volcaniclastic in Sarayan
Investigation of Geological and Environmental Factors of Airborne Suspended Particles from Sand and Gravel Quarries in The West of Tehran, Iran
Introduction: Particulate matter (PM) is known as the most common cause of air pollution in the world. Activities of sand quarries are known as one of the emission sources in Tehran. This study aimed at investigating the geological and environmental factors of airborne particles in an active quarry in the west of Tehran. Material and Methods: Three methods of dust sampling were used. totally, 32 samples were analyzed by Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX). The data were analyzed through Principal Component Analysis (PCA), Enrichment Factor (EF) and Geo-accumulation Index (Igeo). Results: The results showed the presence of Si, Ca, Al, Na, Fe, K, Zn, Pb, P, S, Mg, Cu, Ti, Mn, Cl and V in dust of the quarry. Also, the elements of Mn, V, Zn, Cu and Pb were shown to have moderate to extremely enrichment and contamination from anthropogenic origin. The silicon and potassium were found to have a natural source originated from igneous and alluvial rocks. Conclusion: In this study, it was shown that fugitive dust generated from sand quarries and related activities have higher concentration of elements than those in the Earth crust due to anthropogenic activities. Further studies on transfer of fugitive dust from sand and gravel quarries to Tehran and assessment of its health impact are suggested
Petrogenesis of Miocene igneous rocks in the Tafresh area (central Urumieh‐Dokhtar magmatic arc, Iran): Insights into mantle sources and geodynamic processes
Cenozoic tectono-magmatism in Iran is widely considered to be related to subduction
of the Neo-Tethys Ocean. We employed whole-rock and mineral geochemistry and
isotopic data of intrusive rocks from Tafresh, central Urumieh-Dokhtar magmatic arc,
to evaluate the role of the mantle in magmatism, to assess the timing of emplacement,
and to interpret the tectonic setting. Rock compositions range from gabbro or
gabbro-diorite (plagioclase + pyroxene ± olivine), to diorite (plagioclase + amphibole
± pyroxene), to granodiorite (quartz + plagioclase + K-feldspar + amphibole + biotite),
exhibiting high-alumina calc-alkaline affinity. Major oxide and trace element variations
vary systematically from less to more evolved rocks suggesting a major role
for fractional crystallization processes. Zircon LA-ICP-MS U–Pb ages of major rock
types are in the range of 24–19 Ma, whereas those of gabbroic dikes are ~17.5 Ma.
ԐNd values range between -1.8 and 3.7, and (87Sr/86Sr)i is narrowly restricted to
0.705–0.706, suggesting a common mantle source. The enrichment in light rare earth
element (REE) enrichment and flat heavy REE patterns couple depletion of Nb–Ta–Ti
indicate that subducting oceanic crust had interacted with the overlying mantle
wedge. High-alumina, mid-Mg# Tafresh plutonic rocks formed from hydrous melts
from which Ca-pyroxene and magnetite crystallized earlier than plagioclase, whereas
late-crystallizing zircon nucleated while magma traversed through lithospheric mantle
and Cadomian crust. Modelling of isotope and incompatible-element patterns suggests
the contribution of no more than ~5% molten sediment or other crustal components
in Tafresh magma, at a developmental stage before most plagioclase and
amphibole had crystallized. The Miocene Tafresh plutons originated during the final
stages of subduction, before the collision between the Arabian and Eurasian plates
Circular RNAs: New players in thyroid cancer
The prevalence of thyroid cancer the most frequent endocrine malignancy, is rapidly increasing. Most of thyroid cancers are relatively indolent, however, some cases still possess a risk of developing into lethal types of thyroid cancer. Regarding its multistep tumorigenesis, the determination of the underlying mechanisms is a vital issue for thyroid cancer therapy. Circular RNAs (circRNAs) are a type of non-coding RNAs with a closed loop structure. Numerous circRNAs have been identified in cancerous tissues. Mounting data recommends that the biological activities of circRNAs, such as serving as microRNA or ceRNAs sponges, interacting with proteins, modulating gene translation and transcription, suggesting that circRNAs will be potential targets as well as agents for the prognosis and diagnosis of diseases, including cancer. Given that circular RNAs acts as oncogenes or tumor suppressors in the thyroid cancer. Several studies documented that circular RNAs via microRNA and protein sponges could regulate a sequences of cellular and molecular mechanisms e.g., apoptosis, angiogenesis, tumor growth, and invasion that are involved in thyroid cancer pathogenesis. Herein, we summarized the role of circular RNAs as therapeutic and diagnostic biomarkers in the thyroid cancer. Moreover, we highlighted the role of these molecules in the pathogenesis of various cancers. © 2020 Elsevier Gmb
Synthesis and characterization of exopolysaccharide encapsulated PCL/gelatin skin substitute for full-thickness wound regeneration.
International audienc
Recent and future trends in sea surface temperature across the Persian Gulf and Gulf of Oman
Abstract
Climate change’s effect on sea surface temperature (SST) at the regional scale vary due to driving forces that include potential changes in ocean circulation and internal climate variability, ice cover, thermal stability, and ocean mixing layer depth. For a better understanding of future effects, it is important to analyze historical changes in SST at regional scales and test prediction techniques. In this study, the variation in SST across the Persian Gulf and Gulf of Oman (PG&GO) during the past four decades was analyzed and predicted to the end of 21st century using a proper orthogonal decomposition (POD) model. As input, daily optimum interpolation SST anomaly (DOISSTA) data, available from the National Oceanic and Atmospheric Administration of the United States, were used. Descriptive analyses and POD results demonstrated a gradually increasing trend in DOISSTA in the PG&GO over the past four decades. The spatial distribution of DOISSTA indicated: (1) that shallow parts of the Persian Gulf have experienced minimum and maximum values of DOISSTA and (2) high variability in DOISSTA in shallow parts of the Persian Gulf, including some parts of southern and northwestern coasts. Prediction of future SST using the POD model revealed the highest warming during summer in the entire PG&GO by 2100 and the lowest warming during fall and winter in the Persian Gulf and Gulf of Oman, respectively. The model indicated that monthly SST in the Persian Gulf may increase by up to 4.3 °C in August by the turn of the century. Similarly, mean annual changes in SST across the PG&GO may increase by about 2.2 °C by 2100