Preconcentration of Trace Amounts of Pb(II) Ions without Any Chelating Agent by Using Magnetic Iron Oxide Nanoparticles prior to ETAAS Determination

This work investigates the potential of magnetic Fe3O4 nanoparticles as an adsorbent for separation and preconcentration of trace amounts of lead from water samples prior to electrothermal atomic absorption spectrometry (ETAAS) determination. No chemical modifier is required in graphite furnace. Pb(II) ion was adsorbed on magnetic Fe3O4 nanoparticles in the pH range of 5.5–6.5, and then magnetic nanoparticles (MNPs) were easily separated from the aqueous solution by applying an external magnetic field; so, no filtration or centrifugation was necessary. After extraction and collection of MNPs, the analyte ions were eluted using HNO3 1.0 mol L−1. Several factors that may affect the preconcentration and extraction process, such as pH, type, and volume of eluent, amount of MNPs, sample volume, salting out effect, and interference ions were studied and optimized. Under the best experimental conditions, linearity was maintained between 0.005–0.5 ng mL−1. Detection limits for lead were 0.8 ng L−1 based on 3Sb. The relative standard deviation of seven replicate measurements of 0.05 ng mL−1 of Pb(II) ions was 3.8%. Finally, the method was successfully applied to extraction and determination of lead ions in the water and standard samples

Lost and found: the radial quantum number of Laguerre-Gauss modes

We introduce an operator linked with the radial index in the Laguerre-Gauss modes of a two-dimensional harmonic oscillator in cylindrical coordinates. We discuss ladder operators for this variable, and confirm that they obey the commutation relations of the su(1,1) algebra. Using this fact, we examine how basic quantum optical concepts can be recast in terms of radial modes.Comment: Some minor typos fixed

Influence of Nanosized Silicon Carbide on Dimensional Stability of Al/SiC Nanocomposite

This study concentrated on the role of particle size of silicon carbide (SiC) on dimensional stability of aluminum. Three kinds of Al/SiC composite reinforced with different SiC particle sizes (25 μm, 5 μm, and 70 nm) were produced using a high-energy ball mill. The standard samples were fabricated using powder metallurgy method. The samples were heated from room temperature up to 500∘C in a dilatometer at different heating rates, that is, 10, 30, 40, and 60∘C/min. The results showed that for all materials, there was an increase in length change as temperature increased and the temperature sensitivity of aluminum decreased in the presence of both micro- and nanosized silicon carbide. At the same condition, dimensional stability of Al/SiC nanocomposite was better than conventional Al/SiC composites

Light intensity effects on production and antioxidant activity of flavonoids and phenolic compounds in leaves, stems and roots of three varieties of Labisia pumila Benth

This research was performed to evaluate the effect of light intensity (310 and 630 μmol m-2s-1) on production and antioxidant activity of flavonoids and phenolic compounds from the leaves, stems and roots in three varieties of Labisia pumila Benth. The experiment was carried out base on randomized complete block design with a factorial arrangement. The results revealed that total phenolic and flavonoid content as well as antioxidant activity in all three varieties had consistently higher values when exposed to high irradiance (70% IR). The highest amount of these components was accumulated in the leaves followed by the roots and stems in all three varieties. The results showed that total flavonoid accumulation was highest in the leaves of L. pumila var pumila (2.94±0.11 mg rutin equivalent /g DW) under 630 μmol m-2s-1 light intensity and total phenolics was highest in L. pumila var alata (3.92±0.06 mg Galic acid equivalent (GAE)/g DW) under the same light intensity. HPLC analyses of phenolics and flavonoids in all three varieties revealed the presence of gallic acid, caffeic acid, kaempferol, naringin and myricetin in the leaves of all three varieties of L. pumila Benth and these compounds increased under 630 μmol m-2s -1 light intensity. Antioxidant activities determined by 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) and ferric reduction antioxidant power (FRAP) assays in all varieties. The results showed significantly (p ≤ 0.05) higher activity with increasing total phenolics and flavonoids in all plant organs under 630 μmol m-2s -1 light intensity compared to 310 μmol m-2s-1. This study indicates the ability of different light intensities to enhance the secondary metabolites such as flavonoid and phenolic compounds as well as their antioxidant activities in all three varieties of L. pumila Benth

Phytochemical screening and antioxidant activity assessment of the leaf stem and root of (Labisia paucifolia)

Researches have focused on medicinal plants in order to extract natural and low cost antioxidants that can help to protect the human body against oxidative stress and replace the synthetic additives that might be carcinogenic. In the present study, the crude extracts of leaves, stems and roots of Labisia paucifolia were investigated for their phytochemical constituents and antioxidant activities. The chemical compositions of bioactive compounds were determined using HPLC and GC-MS and the antioxidant activities measured by DPPH and FRAP methods. The results indicated that leaves methanolic extract had highest total phenolic and flavonoid contents with respective values of 2.51 mg gallic acid equivalent g DW-1 and 1.29 mg rutin equivalent g DW-1, compared to roots and stems. Meanwhile, the HPLC analysis showed the presence of gallic acid and kaempferol as the major phenolic and flavonoid compounds in all parts of L. paucifolia. Other metabolites were detected by GC-MS screening including 9,12,15-Octadecatrienoic acid, methyl ester (22.72%), 4H-Pyran-4-0ne,2,3-dihydro-35-dihydroxy-6-methyl (7.93%) and acetic acid (9.02%) as the main compounds in the leaf, stem and root extracts of L. paucifolia. The extracts possess antioxidant activity because the free radical scavenging and ferric reducing power activities were higher in leaf extract at a concentration of 500 μg mL-1 with values of 53% and 51%, respectively, as compared to the stem and root, but the activities were around 32-53% lower than those of antioxidant standards such as BHT and α-tocopherol. The present result revealed that L. paucifolia extracts contain variable patterns of flavonoids, phenolics and various bioactive volatile compounds and it could be applied as a natural antioxidant source for industrial purposes

Adaptive compressive tomography with no a priori information

Quantum state tomography is both a crucial component in the field of quantum information and computation, and a formidable task that requires an incogitably large number of measurement configurations as the system dimension grows. We propose and experimentally carry out an intuitive adaptive compressive tomography scheme, inspired by the traditional compressed-sensing protocol in signal recovery, that tremendously reduces the number of configurations needed to uniquely reconstruct any given quantum state without any additional a priori assumption whatsoever (such as rank information, purity, etc) about the state, apart from its dimension.Comment: 6 pages, 4 figure

Quantum metrology at the limit with extremal Majorana constellations

Quantum metrology allows for a tremendous boost in the accuracy of measurement of diverse physical parameters. The estimation of a rotation constitutes a remarkable example of this quantum-enhanced precision. The recently introduced Kings of Quantumness are especially germane for this task when the rotation axis is unknown, as they have a sensitivity independent of that axis and they achieve a Heisenberg-limit scaling. Here, we report the experimental realization of these states by generating up to 21-dimensional orbital angular momentum states of single photons, and confirm their high metrological abilities

Morphological and molecular characteristics of spheroid formation in HT-29 and Caco-2 colorectal cancer cell lines

Background: Relapse and metastasis in colorectal cancer (CRC) are often attributed to cancer stem-like cells (CSCs), as small sub-population of tumor cells with ability of drug resistance. Accordingly, development of appropriate models to investigate CSCs biology and establishment of effective therapeutic strategies is warranted. Hence, we aimed to assess the capability of two widely used and important colorectal cancer cell lines, HT-29 and Caco-2, in generating spheroids and their detailed morphological and molecular characteristics. Methods: CRC spheroids were developed using hanging drop and forced floating in serum-free and non-attachment conditions and their morphological features were evaluated by scanning electron microscopy (SEM). Then, the potential of CSCs enrichment in spheroids was compared to their adherent counterparts by analysis of serial sphere formation capacity, real-time PCR of key stemness genes (KLF4, OCT4, SOX2, NANOG, C-MYC) and the expression of potential CRC-CSCs surface markers (CD166, CD44, and CD133) by flow cytometry. Finally, the expression level of some EMT-related (Vimentin, SNAIL1, TWIST1, N-cadherin, E-cadherin, ZEB1) and multi-drug resistant (ABCB1, ABCC1, ABCG2) genes was evaluated. Results: Although with different morphological features, both cell lines were formed CSCs-enriched spheroids, indicated by ability to serial sphere formation, significant up-regulation of stemness genes, SOX2, C-MYC, NANOG and OCT4 in HT-29 and SOX2, C-MYC and KLF4 in Caco-2 spheroids (p-value < 0.05) and increased expression of CRC-CSC markers compared to parental cells (p-value < 0.05). Additionally, HT-29 spheroids exhibited a significant higher expression of both ABCB1 and ABCG2 (p-value = 0.02). The significant up-regulation of promoting EMT genes, ZEB1, TWIST1, E-cadherin and SNAIL1 in HT-29 spheroids (p-value = 0.03), SNAIL1 and Vimentin in Caco-2 spheroids (p-value < 0.05) and N-cadherin down-regulation in both spheroids were observed. Conclusion: Enrichment of CSC-related features in HT-29 and Caco-2 (for the first time without applying special scaffold/biochemical) spheroids, suggests spheroid culture as robust, reproducible, simple and cost-effective model to imitate the complexity of in vivo tumors including self-renewal, drug resistance and invasion for in vitro research of CRC-CSCs. © 2021, The Author(s)