A tandem ionic liquid-based dispersive microextraction method using in-syringe air-assisted vesicle system for rapid determination of lead and cadmium in artificial sweat extract of facial cosmetic products

In the present study an innovative tandem ionic liquid-based dispersive microextraction method using an in-syringe air-assisted vesicle system was developed to determine the ultra-trace levels of lead (Pb^II) and cadmium (Cd^II) ions in synthetic sweat extract of branded and nonbranded facial cosmetic products. This method is based on injecting 2-amino-3-sulfhydrylpropanoic acid (l -cysteine) (as an eco-friendly chelating agent), hexafluorophosphate ion [PF₆⁻] (as an ion pair agent) and 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM] [PF₆] (as an acceptor phase) into the synthetic sweat extract of facial cosmetic products (branded and nonbranded). The acceleration of the dispersion process was carried out by rapid pressure in the syringe through the back-and-forth movement of plunger. The sediment phase was removed following centrifugation, and then hydrophobic complexes of analyte were back-extracted into HNO₃ and finally injected into a flame atomic absorption spectrometer. Several factors were systematically optimized. The validity of the methodology was tested by analyzing spiked known standards of both metals in a real sample. The proposed method was applied to the artificial sweat extracts of face makeup products, indicating how much toxic metals from different cosmetics are directly absorbed into skin.     

Novel oxidation of tetrasubstituted furans by pyridinium chlorochromate

A novel oxidation of tetrasubstituted furans with pyridinium chlorochromate has been studied and this has led to a convenient synthesis of 4-acetoxy-3-acetyl- or methoxycarbonyl-4-substituted phenylbut-3-en-2-one.     

Enhancing single-molecule magnet behavior of linear Co<Superscript>II</Superscript>-Dy<Superscript>III</Superscript>Co<Superscript>II</Superscript> complex by introducing bulky diamagnetic moiety

Single-molecule magnets (SMMs) are regarded as promising candidates for ultrahigh-density storage, quantum information processing and molecular spintronics. It is a crucial challenge for chemists to modulate magnetic dynamics of SMMs. Here, we successfully synthesized two 3d-4f polynuclear compounds [Co₂Dy(TTTT^Cl)₂(MeOH)]NO₃·3MeOH (1) and [Co₂Dy(TTTT^Cl)₂ (MeOH)][Co(HTTTT^Cl)](NO₃)₂·2.5MeOH·2H₂O (2), where H₃TTTT^Cl=2,2′,2′′-(((nitrilotris(ethane-2,1-diyl)) tris(azanediyl)) tris(methylene))tris-(4-chlorophenol). On applying the approach by co-crystallization of bulky diamagnetic moiety, the effective energy barrier enhances from 401 K (1) to 536 K (2), which are both among the highest d-f heterometallic SMMs.     

A perspective on non-enzymatic electrochemical nanosensors for direct detection of pesticides

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Removal of the phosphate group in mechanism-based inhibitors of inositol monophosphatase leads to unusual inhibitory activity

Inositol monophosphatase is widely held to be the therapeutic target for inhibition by lithium ion in the treatment of bipolar disorder. In a continued effort to improve the bioavailability of alternative inhibitors, we have designed and tested two new series of compounds; phosphonates and product-like mimics. Phosphonate substrate mimics were competitive inhibitors of reduced potency as compared to phosphate based inhibitors. Product mimics however, showed various inhibitory modes of action. The 6-butylamino derivative 6p was an uncompetitive inhibitor when acting alone (K(i)= 0.3 mM) but displayed non-competitive inhibition in the presence of inorganic phosphate. This compound represents a new lead in the search for a viable replacement for lithium ion therapy.     

On the use of sensitivity analysis in model reduction to predict flows for varying inflow conditions

The proper orthogonal decomposition (POD)‐based model reduction method is more and more successfully used in fluid flows. However, the main drawback of this methodology rests in the robustness of these reduced order models (ROMs) beyond the reference at which POD modes have been derived. Any variation in the flow or shape parameters within the ROM fails to predict the correct dynamics of the flow field. To broaden the spectrum of these models, the POD modes should have the global characteristics of the flow field over which the predictions are required. Mixing of snapshots with varying parameters is one way to improve the global nature of the modes but is computationally demanding because it requires full‐order solutions for a number of parameter values in order to assemble atextitrich enough database on which to perform POD. Instead, we have used sensitivity analysis (SA) to include the flow and shape parameters influence during the basis selection process to develop more robust ROMs for varying viscosity (Reynolds number), changing orientation and shape definition of bodies. This study aims at extending these ideas to inflow conditions to demonstrate the effectiveness of the proposed approach in capturing the effect of varying inflow on the dynamics of the flow over an elliptic cylinder. Numerical experiments show that the newly derived models allow for a more accurate representation of the flows when exploring the parameter space. Copyright © 2011 John Wiley & Sons, Ltd.     

Hybrid anion exchange membrane of hydroxyl-modified polysulfone incorporating guanidinium-functionalized graphene oxide

Incorporating nanofillers is an effective method to balance conductivity and mechanical strength of anion exchange membranes (AEMs). In this work, a series of AEMs were prepared via embedding guanidinium-functionalized graphene oxide (GGO) into un-quaternized, diethanolamine-modified polysulfone (HPSf). The improved hydrophilicity of HPSf allows for better compatibility between GGO and polymer and also gives higher water uptake, which is beneficial for facilitating ion transport and alleviating hydroxide attack. AEM of HPSf embedding an optimized amount of GGO (0.88 mmol g^?1) exhibits the highest conductivity of 11 mS cm^?1 at 30 °C, which is 38% higher than that of pristine PSf-GGO membrane. It also possesses excellent anti-swelling stability (9% swelling ratio at 60 °C). When treated with 1 M NaOH at 60 °C for 120 h, HPSf-GGO-25% experienced a conductivity decay by 25%. Our work provides a route to fabrication of hybrid AEMs with improved interface properties and well-balanced conductivity and robustness.