Novel Zn-Fe LDH/MWCNTs and Graphene/MWCNTs Nanocomposites Based Potentiometric Sensors for Benzydamine Determination in Biological Fluids and Real Water Samples

Two sensitive and selective potentiometric sensors based on zinc-iron layered double hydroxides/multiwalled carbon nanotubes (Zn−Fe LDH/MWCNTs) (sensor I) and graphene/multiwalled carbon nanotubes (Gr/MWCNTs) (sensor II) nanocomposites were developed for benzydamine hydrochloride (Benz) determination. The investigated sensors displayed excellent Nernstian slopes 58.5±0.7 and 59.5±0.5 mV decade⁻¹, detection limits 8.3×10⁻⁷ and 1.9×10⁻⁷ mol L⁻¹, long lifetimes, adequate selectivity, high chemical, and thermal stability within pH range of 2.4–8.5 for sensors І and ІІ, respectively. The surface morphology of sensors was analyzed using a Transmission Electron Microscope (TEM). The analytical method was efficiently implemented for Benz determination in biological fluids and surface water samples.     

Novel diphenylamine 2,4'-dicarboxamide based azoles as potential epidermal growth factor receptor inhibitors: synthesis and biological activity

Several hybrid molecules of diphenylamine-2,4'-dicarboxamide with various azolidinones and related heterocyclic rings have been synthesized and explored as epidermal growth factor receptor (EGFR) kinase inhibitors. Most of them displayed promising in vitro tyrosine kinase inhibition as well as potent cellular antiproliferative activity in the EGFR over-expressing breast cancer cell line (MCF-7). Compounds 12b and 13b that exhibited the highest inhibition in the kinase assay (89, 81% inhibition at 10 μM, respectively), showed potent antiproliferative effect against MCF-7 tumor cell line (IC(50) 1.04, 0.91 μM respectively). Molecular docking studies revealed that these compounds can bind to ATP binding site of the EGFR kinase domain and were involved in H-bonding with Met 793, in analogy to the known EGFR tyrosine kinase inhibitors. Moreover, compounds 15a-c possessed profound antitumor activity (IC(50) 0.59-0.73 μM) and significant EGFR-TK inhibition, making them of particular interest. In summary, the newly synthesized compounds provide promising new lead for the future design and development of anticancer agents of potential EGFR-TK inhibitory activity.     

Improving weak efficiency frontiers in the fuzzy data envelopment analysis models

Evaluating the performance of activities or organization by common data envelopment analysis models requires crisp input/output data. However, the precise inputs and outputs of production processes cannot be always measured. Thus, the data envelopment analysis measurement containing fuzzy data, called “fuzzy data envelopment analysis”, has played an important role in the evaluation of efficiencies of real applications. This paper focuses on the fuzzy CCR model and proposes a new method for determining the lower bounds of fuzzy inputs and outputs. This improves the weak efficiency frontiers of the corresponding production possibility set. Also a numerical example illustrates the capability of the proposed method.     

Characterization of mediastinal lymphadenopathy with diffusion-weighted imaging

Purpose

To predict malignancy of mediastinal lymphadenopathy with diffusion-weighted imaging.

Material and methods

A prospective study was conducted on 35 patients with mediastinal lymphadenopathy (28 malignant and seven benign nodes). They underwent echoplanar diffusion-weighted magnetic resonance imaging of the mediastinum with b-factors of 0, 300 and 600 s/mm². The apparent diffusion coefficient (ADC) values of the mediastinal lymph nodes were calculated. The ADC values were correlated with the biopsy results and statistical analysis was done. A value of P<.05 was considered significant.

Results

The mean ADC value of malignant mediastinal lymphadenopathy (1.06±0.3×10⁻³ mm²/s) was significantly lower (P=.001) than that of benign lymphadenopathy (2.39±0.7×10⁻³ mm²/s). There was an insignificant difference in the ADC values between metastatic and lymphomatous mediastinal lymph nodes (P=.32) as well as within benign nodes (P=.07). When an ADC value of 1.85×10⁻³ mm²/s was used as a threshold value for differentiating malignant mediastinal nodes from benign nodes, the best results were obtained with an accuracy of 83.9%, a sensitivity of 96.4%, a specificity of 71.4%, a negative predictive value of 95.2% and a positive predictive value of 77.1%. The area under the curve was 0.98.

Conclusion

Diffusion weighted magnetic resonance imaging is a promising noninvasive imaging modality that can be used for characterization of mediastinal lymphadenopathy and differentiation of malignant from benign mediastinal lymph nodes.     

Chemically Orthogonal Three‐Patch Microparticles

Compared to two‐dimensional substrates, only a few methodologies exist for the spatially controlled decoration of three‐dimensional objects, such as microparticles. Combining electrohydrodynamic co‐jetting with synthetic polymer chemistry, we were able to create two‐ and three‐patch microparticles displaying chemically orthogonal anchor groups on three distinct surface patches of the same particle. This approach takes advantage of a combination of novel chemically orthogonal polylactide‐based polymers and their processing by electrohydrodynamic co‐jetting to yield unprecedented multifunctional microparticles. Several micropatterned particles were fabricated displaying orthogonal click functionalities. Specifically, we demonstrate novel two‐ and three‐patch particles. Multi‐patch particles are highly sought after for their potential to present multiple distinct ligands in a directional manner. This work clearly establishes a viable route towards orthogonal reaction strategies on multivalent micropatterned particles.     

Up-conversion enhancement in Er3 +-Ag co-doped zinc tellurite glass: Effect of heat treatment

The melt quenching method was used to synthesize the Ag⁰ nanoparticles and Er^3 + ions co-doped zinc tellurite glass. The glasses were characterized by differential thermal analyzer, UV–VIS-IR absorption, photoluminescence spectroscopy and TEM imaging. Heat treatment at different annealing time intervals above the glass transition temperature was applied to reduce the Ag⁺ ions to Ag⁰ NPs. The influence of heat treatment on structural and optical properties is examined. Intense and broad up-conversion emissions of silver are recorded in the visible region. Up-conversion luminescence spectra revealed three major emission peaks at 520, 550 and 650 nm originating from ²H_11/2, ⁴S_3/2 and ⁴F_9/2 levels, respectively. An efficient enhancement in visible region is observed for samples containing silver NPs. The absorption plasmon peaks are evidenced around 560 and 594 nm. The effect of localized surface plasmon resonance and the energy transfer from the surface of silver NP to trivalent erbium ions are described as the sources of enhancement.     

Density Functional Theory Studies on the Oxidation of 5'-dGMP and 5'-dAMP by a Platinum(IV) Complex

Density functional theory has been used to investigate the oxidation of a guanine nucleotide by platinum(IV), a process that can be important in the degradation of DNA. For the first time, we have provided a comprehensive mechanism for all of the steps in this process. A number of intermediates are predicted to occur but with short lifetimes that would make them difficult to observe experimentally. A key step in the mechanism is electron transfer from guanine to platinum(IV), and we show that this is driven by the loss of a chloride ligand from the platinum complex after nucleophilic attack of 5'-phosphate to C8 of guanine. We have investigated several different initial platinum(IV) guanine adducts and shown that the adduct formed from replacement of an axial chlorine ligand in the platinum(IV) complex undergoes oxidation more easily. We have studied adenine versus guanine adducts, and our results show that oxidation of the former is more difficult because of disruption of the aromatic π system that occurs during the process. Finally, our results show that the acidic hydrolysis step to form the final oxidized product occurs readily via an initial protonation of N7 of the guanine.     

Complexes of 2-hydroxynaphthalene-1-carboxaldehyde with transition metal ions

New 2-hydroxynaphthalene-1-carboxaldehyde (Hhnca) complexes M(hnca)₃ (M = Cr, Fe,Ru or Rh), M(hnca)₂ (M=Co, Ni,Cu or Pd),trans-MO₂(hnca)₂(M = Os, U), [Ag(hnca)₂]^-, ReO(PPh₃)(hnca)₂I, [Cu(py)₂(hnca)]⁺, [Ni(bipy)₂(hnca)]⁺ and [CoL₂(hnca)]⁺ (L=bipy or py₂) are described. Their i.r., Raman, ¹H-n.m.r. and electronic spectra and magnetic moments have been measured and are discussed. The proton–ligand formation constant (pK^*_A) of the ligand has been determined potentiometrically.     

A theoretical study of electronic effects in alkyne‐linked reactive intermediates: (nitrenoethynyl)methylenes, (nitrenoethynyl)silylenes,and (nitrenoethynyl)germylenes

Acetylene‐linked reactive intermediates of (nitrenoethynyl)‐X‐methylenes, (nitrenoethynyl)‐X‐silylenes, and (nitrenoethynyl)‐X‐germylenes are almost experimentally unreachable (X–M–C≡C–N; X=H ( 1 ), CN ( 2 ), OH ( 3 ), NH₂ ( 4 ), NO₂ ( 5 ), and CHO ( 6 ); M=C, Si, and Ge). The effects of the electron‐donating and electron withdrawing groups were compared and contrasted at seven levels of theory. All singlet species as ground states with one local open‐shell singlet carbene subunit (π¹π¹) and another local open‐shell singlet nitrene subunit (π¹π¹) were found to be more stable than their corresponding triplets including one local open‐shell singlet carbene (δ¹π¹) (or one local closed‐shell singlet carbene [δ²π⁰]) and another local triplet nitrene subunit (π¹π¹) with 45.94–77.996 kcal/mol singlet–triplet energy gap (ΔE_s‐t). Their relative silylenes and germylenes made reduction of ΔE_s‐t, so the triplet ground states were found for species 3 _Si , 4 _Si , 5 _Si , 2 _Ge , 3 _Ge , 4 _{Ge ,} and 5 _Ge . All the singlet silylenes/germylenes formed by one local closed‐shell singlet silylenes/germylenes (δ²π⁰) and one local closed‐shell singlet nitrene subunit (π²π⁰). Also, one local closed‐shell singlet silylene/germylene subunit (δ²π⁰) and one local triplet nitrene subunit (π¹π¹) were observed for triplet silylenes/germylenes. The singlet and triplet species 3 _Si , 4 _Si , 3 _Ge , and 4 _Ge , due to their electrophilic (Si₄/Ge₄) and nucleophilic (X₅) centers, could be identified as intermediates in chemical reactions.     

Synthesis of novel rhodanine based functionalized furans from the reaction of tert-butyl isocyanide with acetylenic esters in the presence of rhodanine acetic acid derivatives

The reactive 1:1 intermediate produced from the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by rhodanine-N-acetic acid derivatives to generate polyfunctionalized furan rings in fairly good yields.