FimH antagonists: structure-activity and structure-property relationships for biphenyl α-D-mannopyranosides

Urinary tract infections (UTIs) are caused primarily by uropathogenic Escherichia coli (UPEC), which encode filamentous surface‐adhesive organelles called type 1 pili. FimH is located at the tips of these pili. The initial attachment of UPEC to host cells is mediated by the interaction of the carbohydrate recognition domain (CRD) of FimH with oligomannosides on urothelial cells. Blocking these lectins with carbohydrates or analogues thereof prevents bacterial adhesion to host cells and therefore offers a potential therapeutic approach for prevention and/or treatment of UTIs. Although numerous FimH antagonists have been developed so far, few of them meet the requirement for clinical application due to poor pharmacokinetics. Additionally, the binding mode of an antagonist to the CRD of FimH can switch from an in‐docking mode to an out‐docking mode, depending on the structure of the antagonist. In this communication, biphenyl α‐D ‐mannosides were modified to improve their binding affinity, to explore their binding mode, and to optimize their pharmacokinetic properties. The inhibitory potential of the FimH antagonists was measured in a cell‐free competitive binding assay, a cell‐based flow cytometry assay, and by isothermal titration calorimetry. Furthermore, pharmacokinetic properties such as log D, solubility, and membrane permeation were analyzed. As a result, a structure–activity and structure–property relationships were established for a series of biphenyl α‐D ‐mannosides.     

Rheological Properties of Soybean β-Conglycinin in Aqueous Dispersions: Effects of Concentration,Ionic Strength and Thermal Treatment

Steady shear and dynamic oscillatory measurements were used to investigate the effect of concentration, ionic strength and thermal treatment on rheological properties of soybean β-conglycinin in aqueous dispersions. SDS-PAGE and Differential Scanning Calorimetry (DSC) showed that β-conglycinin exhibited partial denaturation and formation of aggregates during isolation. Under steady shear flow, strong shear-thinning behavior was observed with increasing shear rate from 0.001 to 1200 s^?1. A dispersion of β-conglycinin (≥5% w/v, without applying thermal treatment) exhibited gel-like dynamic mechanical spectra at 20°C. This suggested that β-conglycinin in aqueous dispersions showed rheological properties of typical weak gel-like (entanglement) or semi diluted polymeric solution. Weak gel network of β-conglycinin was susceptible to ionic strength, suggesting that electrostatic forces play an important role in the formation of weak gel network. These properties of β-conglycinin have practical significance for the food processors in the formulation of new products.     

Effect of CuO-, SiO2-, and Al2O3-based nanofluids on automotive cooling systems from laminar to turbulent flow regime—A CFD study

In recent studies, much attention has been given to nanofluids suggesting that adding nanoparticles in base fluids offers a higher heat transfer rate compared with conventional fluids. This study is based on the numerical investigation of different types of nanofluids, consisting of CuO (50 nm), SiO₂ (40 nm), and Al₂O₃ (15 nm) nanoparticles at different volume concentrations. Several simulations were performed from low to high Reynolds numbers, corresponding to laminar and turbulent flow regimes using ANSYS-Fluent CFD solver. Results suggest that under a laminar flow regime with the same Reynolds number of 2000, CuO-based nanofluids perform better as compared with SiO₂ and Al₂O₃-based nanofluids with Nusselt number (Nu) having percentage increase of 90% and 60% comparing with SiO₂- and Al₂O₃-based nanofluids, respectively. However, at higher Reynolds numbers when the flow is turbulent, Al₂O₃-based nanofluids demonstrate better performance having a percentage increase in Nusselt numbers equal to 40% and 23% as compared with CuO and SiO₂-based nanofluids respectively under the same Reynolds number of 15,000. This implies that turbulence has a significant effect on heat transfer rate, and is not only related to thermal conductivity. This study will help in designing more compact cooling systems for engines and the internal environment of motor vehicles.     

Effects of individual and combined administration of ochratoxin A and aflatoxin B1 in tissues and eggs of White Leghorn breeder hens

BACKGROUND: Mycotoxins, the secondary fungal metabolites, are unavoidable contaminants of human and animal food and feeds. The objectives of this study were to evaluate the effect of concurrent feeding of ochratoxin A (OTA) and aflatoxin B₁ (AFB₁) to breeder hens, upon their deposition in different tissues and eggs. RESULTS: Residues of OTA and AFB₁ in (ng g^?1) were significantly higher in liver followed by kidneys and breast muscles by 22.54 ± 1.48, 4.22 ± 0.93 and 0.56 ± 0.06 for OTA (group fed OTA at 5 mg kg^?1 diet) and 1.44 ± 0.21, 0.25 ± 0.01 and 0.03 ± 0.01 for AFB₁ (group fed AFB₁ at 5 mg kg^?1 diet), respectively. Residues of OTA and AFB₁ in eggs appeared at days 3 and 5 of toxin feeding and disappeared at days 5 and 6 of withdrawal of mycotoxins contaminated feed, respectively. The residues of OTA and AFB₁ were significantly lower in the tissues of hens fed these toxins concurrently compared with the groups fed OTA and AFB₁ independently. CONCLUSIONS: Residues of OTA and AFB₁ appeared in the tissues and eggs of laying hens kept on OTA‐ and AFB₁‐contaminated diets. Concurrent feeding of OTA and AFB₁ to hens significantly decreased the concentration of OTA and AFB₁ residues in the tissues and eggs. Copyright © 2011 Society of Chemical Industry     

An investigation into gamma-ray treatment of shellfish using electron paramagnetic resonance spectroscopy

BACKGROUND: Gamma irradiation is a safe method for the decontamination of shellfish, and its technical feasibility and safety have been endorsed (FAO/IAEA/WHO). In order to implement proper food‐processing regulations, the identification of radiation treatment is required. In this study, electron paramagnetic resonance (EPR) spectroscopy was employed to identify the irradiation of seven different types of commonly consumed shellfish. RESULTS: Characteristics (g factor and signal intensity) of the EPR spectra of control and irradiated samples were recorded in order to clarify the gamma‐ray treatment of shellfish. Radiation‐specific signals around g = 2.0038 ± 0.0006 (g₁) and g = 1.9996 ± 0.0002 (g₂ and g₃) were observed for all shellfish samples irradiated with absorbed doses of 3 and 6 kGy. The X‐ray diffraction (XRD) spectra of some shellfish samples were recorded to investigate their mineral profiles. CONCLUSION: The EPR spectroscopic results indicated that carbonate minerals were the source of the paramagnetic species that were produced upon irradiation, entrapped in the shellfish and showed radiation‐specific asymmetric signals whose intensities increased quantitatively with the absorbed radiation dose. The XRD analysis revealed that aragonite and calcite minerals were present in the shells of shellfish. Copyright © 2011 Society of Chemical Industry     

Surface modification of polypropylene waste by the radiation grafting of styrene and upcycling into a cation-exchange resin

In this study, we radiation-grafted polypropylene waste (PPw) powder obtained from the accelerated aging of pristine polypropylene with styrene (St) using γ rays from a Co-60 source at dose rate of 4.78 kGy/h. The influence of the variation of the γ absorbed dose, solvent types, and monomer concentration on the grafting yield was investigated. Solution grafting in methanol resulted in a higher grafting yield of 162.6% at 30 kGy in contrast to the 69.5% obtained in the absence of solvent. Grafting was found to be enhanced with the increased dilution of St with methanol. The grafted St units were incorporated with sulfonic ( SO₃H) groups by a sulfonation reaction with sulfuric acid. Fourier transform infrared spectroscopy, X-ray diffraction spectrometry, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and thermogravimetric analysis were used to characterize the grafted and sulfonated products. Sulfonation of 162.6% grafted PPw powder exhibited a maximum ion-exchange capacity (IEC) of 3.56 mequiv/g. The utilization of PPw and its conversion into sulfonated PPw with comparable IECs is a new addition to already existing radiation grafting systems. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47145.     

Creep of Single Crystals of Nickel-Based Superalloys at Ultra-High Homologous Temperature

The creep behavior of single crystals of the nickel-based superalloy CMSX-4 was investigated at 1288 °C, which is the temperature of the hot isostatic pressing treatment applied to this superalloy in the industry. It was found that at this super-solvus temperature, where no γ′-strengthening occurs, the superalloy is very soft and rapidly deforms under stresses between 4 and 16 MPa. The creep resistance was found to be very anisotropic, e.g., the creep rate of [001] crystals was about 11 times higher than that of a [111] crystal. The specimens of different orientations also showed a very different necking behavior. The reduction of the cross-sectional area ψ of [001] crystals reached nearly 100 pct, while for a [111] crystal ψ?=?62 pct. The EBSD analysis of deformed specimens showed that despite such a large local strain the [001] crystals did not recrystallize, while a less deformed [111] crystal totally recrystallized within the necking zone. The recrystallization degree was found to be correlated with deformation behavior as well as with dwell time at high temperature. From the analysis of the obtained results (creep anisotropy, stress dependence of the creep rate, traces of shear deformation, and TEM observations), it was concluded that the main strain contribution resulted from 〈\( 0 1\bar{1} \)〉{111} octahedral slip.     

A genetic algorithm for solving no-wait flexible flow lines with due window and job rejection

This paper addresses a no-wait multi-stage flexible flow shop problem. There are n jobs to complete in a predetermined due window; hence, some jobs may be rejected. A mixed integer linear programming model with the objective of maximizing the total profit gained from scheduled jobs is introduced. Since the problem is NP-hard and difficult to find an optimal solution in a reasonable computational time, an efficient genetic algorithm is presented as the solution procedure. A heuristic mechanism is proposed to use in each generation of the genetic algorithms to assure the feasibility and superior quality of the obtained solutions. Computational results show that the presented approach performs considerably in terms of both quality of solutions and required runtimes.     

Sintering/shrinkage kinetics of metal injection molded copper brown body

The sintering shrinkage kinetics of metal injection molded copper brown parts was investigated at three different heating rates up to 1050 °C using a high temperature pushrod dilatometer. Non-isothermal and isothermal measurements were simultaneously used in the multivariate non-linear regression analysis to determine the kinetic reaction parameters. A four-step kinetic model was established using “Jander” diffusion equation. Using the rate control sintering, the temperature-time profile for the predefined shrinkage was achieved with respect to time saving. The temperature-time profile was confirmed by performing an experimental run in the production furnace. The metallographic analysis of the microstructure and determination of the sintered density revealed the validation of calculated temperature-time profile.