T3P-promoted synthesis of a series of novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones

A series of 11 novel 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-aryl-C-phenyl imines with thiosalicylic acid. This provides simple and ready access to N-aryl compounds in this family, which have been generally difficult to prepare.     

Multivariate Versus Classical Univariate Calibration Methods for Spectrofluorimetric Data: Application to Simultaneous Determination of Olmesartan Medoxamil and Amlodipine Besylate in their Combined Dosage Form

Olmesartan medoxamil (OLM, an angiotensin II receptor blocker) and amlodipine besylate (AML, a dihydropyridine calcium channel blocker), are co-formulated in a single-dose combination for the treatment of hypertensive patients whose blood pressure is not adequately controlled on either component monotherapy. In this work, four multivariate and two univariate calibration methods were applied for simultaneous spectrofluorimetric determination of OLM and AML in their combined pharmaceutical tablets in all ratios approved by FDA. The four multivariate methods are partial least squares (PLS), genetic algorithm PLS (GA-PLS), principal component ANN (PC-ANN) and GA-ANN. The two proposed univariate calibration methods are, direct spectrofluorimetric method for OLM and isoabsorpitive method for determination of total concentration of OLM and AML and hence AML by subtraction. The results showed the superiority of multivariate calibration methods over univariate ones for the analysis of the binary mixture. The optimum assay conditions were established and the proposed multivariate calibration methods were successfully applied for the assay of the two drugs in validation set and combined pharmaceutical tablets with excellent recoveries. No interference was observed from common pharmaceutical additives. The results were favorably compared with those obtained by a reference spectrophotometric method.     

Acacetin Inhibits Cell Proliferation and Induces Apoptosis in Human Hepatocellular Carcinoma Cell Lines

Human hepatocellular carcinoma (HCC) is the fifth most common cancer and the third leading cause of death across the world. Recent evidence suggests that STAT3 regulates proliferative, survival, metastasis, and angiogenesis genes in HCC. Novel agents that suppress STAT3 activation can be used to prevent or treat HCC. We used a functional proteomics tumor pathway technology platform and multiple HCC cell lines to investigate the effects of acacetin (ACN) on STAT3 activation, protein kinases, phosphatases, products of STAT3-regulated genes, and apoptosis. ACN was found to inhibit STAT3 activation in a dose- and time-dependent manner in HCC cells. Upstream kinases c-Src, Janus-activated kinase 1, and Janus-activated kinase 2 were also inhibited. The ACN inhibition of STAT3 was abolished by vanadate treatment, suggesting the involvement of tyrosine phosphatase activity. ACN was found to suppress the protein expression of genes involved in proliferation, survival, and angiogenesis via STAT3 inhibition. ACN appears to be a novel STAT3 inhibitor and may be a promising therapeutic compound for application in the treatment of HCC and other cancers.     

New Polymer Syntheses Part 60: A Facile Synthetic Route to Polyamides Based on Thieno[2,3-b]thiophene and Their Corrosion Inhibition Behavior

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer 1 a with different kinds of diacid chlorides(including oxalyl, adipoyl, sebacoyl, isophthaloyl,terephthaloyl, 4,4′-azodibenzoyl, 3,3′-azodibenzoyl, p-phenylene diacryloyl) in the presence of Li Cl and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy(including ~1H-NMR and ~(13)C-NMR) and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis(TGA), wide-angle X-ray diffraction analysis(WAXD) and scanning electron microscopy(SEM). Also, the corrosion inhibition behavior of selected examples of polyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol·L~(-1) HCl was studied using potentiodynamic polarization(PDP) and electrochemical impedance spectroscopy(EIS) methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency(P, %) was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer.The adsorption of these polymers was found to obey Langmuir adsorption isotherm.     

Novel Cellulose Derivatives Containing Metal (Cu,Fe, Ni) Oxide Nanoparticles as Eco-Friendly Corrosion Inhibitors for C-Steel in Acidic Chloride Solutions

Novel environmentally-friendly corrosion inhibitors based on primary aminated modified cellulose (PAC) containing nano-oxide of some metals (MONPs), for instance iron oxide nanoparticles (Fe₃O₄NPs), copper oxide nanoparticles (CuONPs), and nickel oxide nanoparticles (NiONPs), were successfully synthesized. The as-prepared PAC/MONPs nanocomposites were categorized using Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and selected area diffraction pattern (SAED) techniques. The data from spectroscopy indicated that successful formation of PAC/MONPs nanocomposites, as well as the TEM images, declared the synthesized PAC/Fe₃O₄NPs, PAC/CuONPs, and PAC/NiONPs with regular distribution with particle size diameters of 10, 23 and 43 nm, respectively. The protection performance of the as-prepared PAC and PAC/MONPs nanocomposites on the corrosion of C-steel in molar HCl was studied by the electrochemical and weight-loss approaches. The outcomes confirmed that the protection power increased with a rise in the [inhibitor]. The protection efficiency reached 88.1, 93.2, 96.1 and 98.6% with 250 ppm of PAC/CuONP, PAC/Fe₃O₄NPs, and PAC/NiONPs, respectively. PAC and all PAC/MONPs nanocomposites worked as mixed-kind inhibitors and their adsorption on the C-steel interface followed the isotherm Langmuir model. The findings were reinforced by FT-IR, FE-SEM and EDX analyses.     

Synthesis of Cationic and Ampholytic Starch Graft Acrylamide and their Aqueous Salt Absorption

Acrylamide was grafted onto starch using ceric(IV) ion as initiator. Starch–graft-polyacrylamide was then modified through Mannich reaction using formaldehyde and diethylamine to give poly(N, N′-[(diethylamino) methyl]-acrylamide). The modified-graft copolymer was quaternized using different reagents; methyl iodide, n-butylbromide, sodium chloroacetate and propane sultone to give cationic and ampholytic graft materials. The absorbing properties of the produced materials toward deionized water and aqueous salt solutions were investigated. Studies of the absorbing properties of polyampholytes have revealed that these materials do not shrink upon increasing salt concentration. Kinetics of swelling in deionized water is also discussed.     

Sample indexed spatial orthogonal frequency division multiplexing

Optical spatial modulation(OSM) is a multiple-transmitter technique that can provide higher data rates with low system complexity as compared with single-input single-output systems. Orthogonal frequency division multiplexing(OFDM) is widely implemented to achieve better spectral efficiency in wireless channels. Asymmetrically clipped optical OFDM(O-OFDM) and DC-biased O-OFDM are two well-known O-OFDM techniques suitable for intensity-modulation direct-detection optical systems. In this work, sample indexed spatial OFDM(SIS-OFDM) is proposed to combine OSM and O-OFDM in a novel way and achieve significant performance gain. By assigning time-domain samples of the O-OFDM transmit symbol to different transmitters, SIS-OFDM achieves much better spectral efficiency and reduces computational complexity at the transmitter as compared with previous work that combines OSM with O-OFDM in the frequency domain. We also consider the impact of optical source biasing on overall performance, and the relative performance of imaging receiver(ImR) versus non-imaging receiver(NImR) design for our proposed SIS-OFDM technique. Results indicate that for an Ntx × Nrx multiple-input multiple-output configuration where Ntx = Nrx = 4, SIS-OFDM using ImR can achieve up to 135 dB of signal-to-noise ratio gain over comparable system using a NImR. Also, using Nsc number of O-OFDM subcarriers provides up to Nsc × log2(Ntx) additional bits per symbol of spectral efficiency over techniques that combine OSM and O-OFDM in the frequency domain.     

Experimental investigation of commercially available lead composite aprons used for diagnostic X-rays

One of the principal diagnostic methods used in all fields of medical services is radiographic examination. To keep the radiation dose received by hospital personnel under normal working conditions as low as reasonably achievable, lead composite apron shields are provided as valuable aids. Intensive use of these accessories could lead to softening and surface defects due to poor handling and being worn-out over time, giving rise to multiple defects across the entire apron. Without routine control, these lead aprons will, within time, contribute significantly to the over-radiation burden to the wearer. However, local defects are highly likely to lead to gross changes in the radiation dose received by the wearer. For this reason, we evaluate the exposure dose resulting from diagnostic X-ray radiation during different imaging procedures. In this study, we used TLD LiF-700 chips to measure the attenuation percentage for four groups of commercial lead composite aprons and to calculate the effective doses to different organs during diagnostic radiological procedures. The results show the importance of lead composite aprons in minimizing effective doses, and the attenuation percentage varied for different vendors; this is due to variations in the constituent material. The average attenuation for lead composite aprons varies from 93.3% to 96.7%, and the average attenuation (%)/weight varies from 16.7% to 20.5%. Acceptance testing of lead composite aprons is essential to ensure that lead composite aprons meet their manufacturers’ specifications and provide the necessary radiation protection for their intended use. The combined and expanded uncertainties accompanying these measurements are 2.78% and 5.57%, respectively.     

Synthesis of tri-substituted biaryl based trianglimines: formation of C3-symmetrical and non-symmetrical regioisomers

2-Functionalised aromatic monoaldehydes were synthesised in good to excellent yields by reacting 4-bromo-2-fluorobenzaldehyde with different secondary amines and phenol. The Suzuki-coupling reaction of the newly functionalised aromatic monoaldehydes with 4-formylphenylboronic acid afforded the corresponding 2-functionalised-4,4'-biphenyldialdehydes in good yields (47-85%). The [3+3]-cyclocondensation reactions of the 2-functionalised-4,4'-biphenyldialdehydes with (1R,2R)-1,2-diaminocyclohexane afforded a mixture of regioisomeric C(3)-symmetrical and non-symmetrical trianglimines. Reduction of the C(3)-symmetrical and the non-symmetrical trianglimines with NaBH(4) in a mixture of THF and MeOH afforded the corresponding trianglamines in high yields.